阅读说明：本技术 显示面板、显示装置、显示模块、电子设备及显示面板的制造方法 (Display panel, display device, display module, electronic device, and method for manufacturing display panel ) 是由 中村太纪 江口晋吾 青山智哉 杉泽希 丸山纯矢 藤田一彦 佐藤将孝 川岛进 于 2018-11-19 设计创作，主要内容包括：抑制显示面板的显示不均匀。提供一种像素的开口率高的显示面板。该显示面板包括第一像素电极、第二像素电极、第三像素电极、第一发光层、第二发光层、第三发光层、第一公共层、第二公共层、公共电极以及辅助布线。第一公共层位于第一像素电极及第二像素电极上。第一公共层具有与第一发光层重叠的部分以及与第二发光层重叠的部分。第二公共层位于第三像素电极上。第二公共层具有与第三发光层重叠的部分。公共电极具有隔着第一公共层及第一发光层与第一像素电极重叠的部分、隔着第一公共层及第二发光层与第二像素电极重叠的部分、隔着第二公共层及第三发光层与第三像素电极重叠的部分、以及与辅助布线的顶面接触的部分。(Display unevenness of the display panel is suppressed. A display panel having a high aperture ratio of pixels is provided. The display panel comprises a first pixel electrode, a second pixel electrode, a third pixel electrode, a first light-emitting layer, a second light-emitting layer, a third light-emitting layer, a first common layer, a second common layer, a common electrode and an auxiliary wiring. The first common layer is located on the first pixel electrode and the second pixel electrode. The first common layer has a portion overlapping with the first light-emitting layer and a portion overlapping with the second light-emitting layer. The second common layer is on the third pixel electrode. The second common layer has a portion overlapping with the third light emitting layer. The common electrode has a portion overlapping the first pixel electrode with the first common layer and the first light-emitting layer interposed therebetween, a portion overlapping the second pixel electrode with the first common layer and the second light-emitting layer interposed therebetween, a portion overlapping the third pixel electrode with the second common layer and the third light-emitting layer interposed therebetween, and a portion in contact with the top surface of the auxiliary wiring.)

1. A display panel, comprising:

a first pixel electrode;

a second pixel electrode;

a third pixel electrode;

a first light-emitting layer;

a second light emitting layer;

a third light emitting layer;

a first common layer;

a second common layer;

a common electrode; and

the auxiliary wiring is arranged on the outer side of the circuit board,

wherein the first light emitting layer is positioned on the first pixel electrode,

the second light emitting layer is positioned on the second pixel electrode,

the third light emitting layer is positioned on the third pixel electrode,

the first light-emitting layer is configured to emit light of a color different from that of light emitted from the second light-emitting layer,

the first light-emitting layer is configured to emit light of the same color as that emitted from the third light-emitting layer,

the first common layer is located on the first pixel electrode and the second pixel electrode,

the first common layer includes a portion overlapping with the first light emitting layer and a portion overlapping with the second light emitting layer,

the second common layer is positioned on the third pixel electrode,

the second common layer includes a portion overlapping with the third light emitting layer,

the common electrode includes a portion overlapping with the first pixel electrode such that the first common layer and the first light-emitting layer are between the common electrode and the first pixel electrode, a portion overlapping with the second pixel electrode such that the first common layer and the second light-emitting layer are between the common electrode and the second pixel electrode, a portion overlapping with the third pixel electrode such that the second common layer and the third light-emitting layer are between the common electrode and the third pixel electrode, and a portion in contact with a top surface of the auxiliary wiring.

2. The display panel according to claim 1, wherein,

wherein the first common layer includes a portion in contact with the second common layer.

3. The display panel according to claim 1, wherein,

wherein the first common layer includes a portion overlapping the second common layer.

4. The display panel according to any one of claims 1 to 3,

the first common layer is located between the first pixel electrode and the first light emitting layer.

5. The display panel according to any one of claims 1 to 3,

the first common layer is located between the first light emitting layer and the common electrode.

6. The display panel according to any one of claims 1 to 3,

wherein the auxiliary wiring and the first pixel electrode are located on the same plane.

7. The display panel according to any one of claims 1 to 3, further comprising a transistor,

wherein the auxiliary wiring and a gate electrode or a source electrode of the transistor are located on the same plane.

8. The display panel according to any one of claims 1 to 3,

wherein the first pixel electrode, the second pixel electrode, and the third pixel electrode all include a reflective electrode and a transparent electrode on the reflective electrode.

9. The display panel according to any one of claims 1 to 3,

wherein the common electrode has visible light transmittance and visible light reflectance.

10. The display panel according to any one of claims 1 to 3,

wherein the auxiliary wiring does not overlap with the first pixel electrode, the second pixel electrode, or the third pixel electrode.

11. A display module, comprising:

the display panel of any one of claims 1 to 3; and

at least one of a connector and an integrated circuit.

12. A display device, comprising:

a first display panel; and

a second display panel having a second display area,

wherein the first display panel and the second display panel are both the display panel of any one of claims 1 to 3,

the first display panel includes a first display region,

the second display panel includes a second display region and a visible light transmitting region,

the second display region is adjacent to the visible light transmitting region,

the first display region includes a portion overlapping the visible light transmission region.

13. An electronic device, comprising:

the display device of claim 12; and

at least one of an antenna, a battery, a casing, a camera, a speaker, a microphone, and an operation button.

14. A display panel, comprising:

a first pixel electrode;

a second pixel electrode;

a third pixel electrode;

a first organic compound layer;

a second organic compound layer;

a common electrode; and

the auxiliary wiring is arranged on the outer side of the circuit board,

wherein the first organic compound layer is located on the first pixel electrode and the second pixel electrode,

the second organic compound layer is on the third pixel electrode,

the first organic compound layer is configured to emit light of the same color as that emitted from the second organic compound layer,

the common electrode includes a portion overlapping with the first pixel electrode such that the first organic compound layer is between the common electrode and the first pixel electrode, a portion overlapping with the second pixel electrode such that the first organic compound layer is between the common electrode and the second pixel electrode, a portion overlapping with the third pixel electrode such that the second organic compound layer is between the common electrode and the third pixel electrode, and a portion in contact with a top surface of the auxiliary wiring.

15. The display panel of claim 14, wherein the first and second electrodes are electrically connected,

wherein the first organic compound layer includes a portion in contact with the second organic compound layer.

16. The display panel of claim 14, wherein the first and second electrodes are electrically connected,

wherein the first organic compound layer includes a portion overlapping with the second organic compound layer.

17. The display panel according to any one of claims 14 to 16,

wherein the first organic compound layer and the second organic compound layer each include a stack of a plurality of light emitting layers.

18. The display panel according to any one of claims 14 to 16,

wherein the first organic compound layer and the second organic compound layer are configured to emit white light.

19. The display panel according to any one of claims 14 to 16,

wherein the auxiliary wiring and the first pixel electrode are located on the same plane.

20. The display panel according to any one of claims 14 to 16, further comprising a transistor,

wherein the auxiliary wiring and a gate electrode or a source electrode of the transistor are located on the same plane.

21. The display panel according to any one of claims 14 to 16,

wherein the first pixel electrode, the second pixel electrode, and the third pixel electrode all include a reflective electrode and a transparent electrode on the reflective electrode.

22. The display panel according to any one of claims 14 to 16,

wherein the common electrode has visible light transmittance and visible light reflectance.

23. The display panel according to any one of claims 14 to 16,

wherein the auxiliary wiring does not overlap with the first pixel electrode, the second pixel electrode, or the third pixel electrode.

24. A display module, comprising:

the display panel of any one of claims 14 to 16; and

at least one of a connector and an integrated circuit.

25. A display device, comprising:

a first display panel; and

a second display panel having a second display area,

wherein the first display panel and the second display panel are both the display panel of any one of claims 14 to 16,

the first display panel includes a first display region,

the second display panel includes a second display region and a visible light transmitting region,

the second display region is adjacent to the visible light transmitting region,

the first display region includes a portion overlapping the visible light transmission region.

26. An electronic device, comprising:

the display device of claim 25; and

at least one of an antenna, a battery, a casing, a camera, a speaker, a microphone, and an operation button.

27. A manufacturing method of a display panel includes the following steps:

forming a first pixel electrode, a second pixel electrode, and a third pixel electrode on the insulating surface;

forming a first common layer on the first pixel electrode and the second pixel electrode;

forming a second common layer on the third pixel electrode through a process different from the process of forming the first common layer;

forming a first light emitting layer on the first pixel electrode and a third light emitting layer on the third pixel electrode using a first mask;

forming a second light emitting layer on the second pixel electrode using a second mask through a process different from the process of forming the first light emitting layer; and

forming a common electrode on the first common layer, the second common layer, the first light emitting layer, the second light emitting layer, and the third light emitting layer.

28. The display panel manufacturing method according to claim 27,

wherein the first common layer is formed using a third mask,

and after the first common layer is formed, moving the third mask parallel to the insulating surface by a distance equivalent to one pixel, and then forming the second common layer using the third mask.

29. The display panel manufacturing method according to claim 27,

wherein the first common layer is formed using a third mask,

a second common layer is formed using a fourth mask,

and the aperture pattern of the third mask is shifted from the aperture pattern of the fourth mask by a distance corresponding to one pixel.

30. A manufacturing method of a display panel includes the following steps:

forming a first pixel electrode, a second pixel electrode, and a third pixel electrode on the insulating surface;

forming a first organic compound layer on the first pixel electrode and the second pixel electrode;

forming a second organic compound layer on the third pixel electrode through a process different from the process of forming the first organic compound layer; and

forming a common electrode on the first organic compound layer and the second organic compound layer,

wherein the first organic compound layer is configured to emit light of the same color as light emitted from the second organic compound layer.

31. The display panel manufacturing method according to claim 30,

wherein the first organic compound layer is formed using a first mask,

and after the first organic compound layer is formed, the first mask is moved in parallel to the insulating surface by a distance equivalent to one pixel, and then the second organic compound layer is formed using the first mask.

32. The display panel manufacturing method according to claim 30,

wherein the first organic compound layer is formed using a first mask,

a second organic compound layer is formed using a second mask,

and the opening pattern of the first mask is shifted from the opening pattern of the second mask by a distance corresponding to one pixel.

33. The display panel manufacturing method according to any one of claims 27 to 30,

and forming an auxiliary wiring by the step of forming the first pixel electrode, the second pixel electrode, and the third pixel electrode.

34. A display device, comprising:

a display panel having flexibility;

a first impact-relaxation layer;

a second impact-relaxation layer;

a first support;

a second support;

a first gear; and

a second gear wheel is arranged on the first gear wheel,

wherein the display panel is positioned between the first impact mitigation layer and the second impact mitigation layer,

the first support body overlaps the display panel with the first impact mitigation layer therebetween, the second support body overlaps the display panel with the first impact mitigation layer therebetween,

the first supporting body is connected with the first gear,

the second supporting body is connected with the second gear,

the first gear and the second gear are engaged with each other, so that the first support body and the second support body operate in synchronization,

the first impact-relaxing layer includes a region fixed to the first support, a region fixed to the second support, and a region not fixed to the first support and the second support,

the display device is configured to be changed from one state to the other of an expanded state in which the first support and the second support are located on substantially the same plane and a folded state in which the first support and the second support are overlapped with each other,

in the folded state, the display panel is bent such that a display surface of the display panel faces inward.

35. The display device as set forth in claim 34,

wherein each of the first and second impact-mitigating layers comprises at least one of urethane, acrylic, and silicone.

Technical Field

One embodiment of the present invention relates to a display panel, a display device, a display module, an electronic apparatus, and a method for manufacturing a display panel.

In addition, one embodiment of the present invention is not limited to the above-described technical field. Examples of the technical field of one embodiment of the present invention include a semiconductor device, a display device, a light-emitting device, an electronic device, an illumination device, an input/output device (for example, a touch panel), a method for driving these devices, and a method for manufacturing these devices.

Background

In recent years, a display panel having a high resolution has been demanded, and for example, a display panel having a large number of pixels, such as a full high-definition (pixel number 1920 × 1080) display panel, a 4K (pixel number 3840 × 2160, 4096 × 2160, or the like) display panel, and an 8K (pixel number 7680 × 4320, 8192 × 4320, or the like) display panel, has been developed.

In addition, the display panel is required to be large. For example, a television device having a screen size exceeding 50 inches in diagonal is mainstream as a home television device. As the screen size increases and the number of pixels increases, the amount of information that can be displayed at one time increases, and there is a demand for further increasing the screen size of a digital signage or the like.

A light-emitting element utilizing an electroluminescence phenomenon (also referred to as an "E L element") has characteristics such as easiness in achieving thinning and weight reduction, capability of responding to an input signal at high speed, and capability of being driven by a direct-current low-voltage power supply, and is therefore considered to be applied to a display panel, and for example, patent document 1 discloses a light-emitting device having flexibility to which an organic E L element is applied.

[ reference documents ]

[ patent document ]

[ patent document 1] Japanese patent application laid-open No. 2014-197522

Disclosure of Invention

Since a transistor, a capacitor, a wiring, and the like can be arranged in the display panel having the top emission structure so as to overlap with a light-emitting region of the light-emitting element, the display panel can achieve a higher pixel aperture ratio than the display panel having the bottom emission structure. On the other hand, in the display panel of the top emission structure, since light emitted from the light emitting element is taken out to the outside through the common electrode, the common electrode needs to transmit visible light. The use of a conductive material that transmits visible light causes a problem that the resistance of the common electrode increases. When a voltage drop due to the resistance of the common electrode occurs, the potential distribution in the display surface becomes uneven, and the luminance of the light-emitting element becomes uneven, so that the display quality is degraded.

One of the objects of one embodiment of the present invention is to suppress display unevenness or luminance unevenness of a display panel or a display device. It is another object of one embodiment of the present invention to provide a display panel or a display device having high display quality. It is another object of one embodiment of the present invention to provide a display panel or a display device having a high aperture ratio of pixels. It is another object of one embodiment of the present invention to provide a display panel or a display device with high reliability.

Further, one of the objects of the embodiment of the present invention is to increase the size of a display device. Further, it is an object of one embodiment of the present invention to provide a display device having a large display area in which a seam is not easily visible. Another object of one embodiment of the present invention is to reduce the thickness and weight of a display device. It is another object of an embodiment of the present invention to provide a display device capable of displaying along a curved surface. It is another object of one embodiment of the present invention to provide a display device having excellent visibility. Further, it is an object of one embodiment of the present invention to provide a novel display panel or a display device.

Note that the description of the above object does not hinder the existence of other objects. An embodiment of the present invention need not achieve all of the above objectives. Objects other than the above objects can be derived from the description of the specification, drawings, and claims.

One embodiment of the present invention is a display panel including a first pixel electrode, a second pixel electrode, a third pixel electrode, a first light emitting layer, a second light emitting layer, a third light emitting layer, a first common layer, a second common layer, a common electrode, and an auxiliary wiring. The first light emitting layer is positioned on the first pixel electrode. The second light emitting layer is positioned on the second pixel electrode. The third light emitting layer is positioned on the third pixel electrode. The first light-emitting layer has a function of emitting light of a different color from the second light-emitting layer. The first light-emitting layer has a function of emitting light of the same color as the third light-emitting layer. The first common layer is located on the first pixel electrode and the second pixel electrode. The first common layer has a portion overlapping with the first light-emitting layer and a portion overlapping with the second light-emitting layer. The second common layer is on the third pixel electrode. The second common layer has a portion overlapping with the third light emitting layer. The common electrode has a portion overlapping the first pixel electrode with the first common layer and the first light-emitting layer interposed therebetween, a portion overlapping the second pixel electrode with the first common layer and the second light-emitting layer interposed therebetween, a portion overlapping the third pixel electrode with the second common layer and the third light-emitting layer interposed therebetween, and a portion in contact with the top surface of the auxiliary wiring. The first common layer may also have a portion in contact with the second common layer. The first common layer may also have a portion overlapping the second common layer.

The first common layer may also be positioned between the first pixel electrode and the first light emitting layer. The first common layer may also be positioned between the first light emitting layer and the common electrode.

Further, one embodiment of the present invention is a display panel including a first pixel electrode, a second pixel electrode, a third pixel electrode, a first organic compound layer, a second organic compound layer, a common electrode, and an auxiliary wiring. The first organic compound layer is located on the first pixel electrode and the second pixel electrode. The second organic compound layer is on the third pixel electrode. The first organic compound layer has a function of emitting light of the same color as the second organic compound layer. The common electrode has a portion overlapping with the first pixel electrode via the first organic compound layer, a portion overlapping with the second pixel electrode via the first organic compound layer, a portion overlapping with the third pixel electrode via the second organic compound layer, and a portion in contact with a top surface of the auxiliary wiring. The first organic compound layer may also have a portion in contact with the second organic compound layer. The first organic compound layer may also have a portion overlapping with the second organic compound layer.

The first organic compound layer and the second organic compound layer may each include a stack of a plurality of light emitting layers. The first organic compound layer and the second organic compound layer may also have a function of emitting white light.

The auxiliary wiring may also be located on the same plane as the first pixel electrode.

The display panel having each of the above structures may further include a transistor, and the auxiliary wiring may be located on the same plane as a gate electrode or a source electrode included in the transistor.

The first pixel electrode, the second pixel electrode and the third pixel electrode may also include a reflective electrode and a transparent electrode on the reflective electrode.

The common electrode may also have visible light transmittance and visible light reflectance.

The auxiliary wiring preferably does not overlap the first pixel electrode, the second pixel electrode, or the third pixel electrode.

Further, an embodiment of the present invention is a display module including: a display panel having any one of the above structures; and at least one of a connector and an integrated circuit.

One embodiment of the present invention is a display device including a first display panel and a second display panel. The first display panel and the second display panel are display panels having any one of the above structures. The first display panel includes a first display region. The second display panel includes a second display region and a visible light transmission region. The second display region is adjacent to the visible light transmission region. The first display region includes a portion overlapping the visible light transmission region.

Further, one embodiment of the present invention is a display device including a flexible display panel, a first impact relaxing layer, a second impact relaxing layer, a first support, a second support, a first gear, and a second gear. The display panel is located between the first impact mitigation layer and the second impact mitigation layer. The first support and the second support are respectively overlapped with the display panel through the first impact relaxation layer. The first supporting body is connected with the first gear. The second support is connected with the second gear. Since the first gear and the second gear are engaged with each other, the operation of the first support body and the operation of the second support body are synchronized. The first impact-mitigating layer has a region fixed to the first support, a region fixed to the second support, and a region not fixed to the first support and the second support. The display device is configured to be changed from one state to the other state from an expanded state in which the first support and the second support are located on substantially the same plane and a folded state in which the first support and the second support are overlapped with each other. In the folded state, the display panel is bent so that the display surface of the display panel faces inward. The first and second impact relaxing layers preferably include at least one of urethane, acrylic, and silicone.

Further, an embodiment of the present invention is an electronic apparatus including: a display device having any one of the above structures; and at least one of an antenna, a battery (secondary battery or the like), a housing, a camera, a speaker, a microphone, and an operation button.

Further, one embodiment of the present invention is a method for manufacturing a display panel, including the steps of: forming a first pixel electrode, a second pixel electrode, and a third pixel electrode on the insulating surface; forming a first common layer on the first pixel electrode and the second pixel electrode; forming a second common layer on the third pixel electrode through a process different from the process of forming the first common layer; forming a first light emitting layer on the first pixel electrode and a third light emitting layer on the third pixel electrode using a first mask; forming a second light emitting layer on the second pixel electrode using a second mask through a process different from the process of forming the first light emitting layer; and forming a common electrode on the first common layer, the second common layer, the first light emitting layer, the second light emitting layer, and the third light emitting layer.

In the above manufacturing method, the first common layer may be formed using a third mask, and after the first common layer is formed, the third mask may be moved parallel to the insulating surface by a distance corresponding to one pixel, and then the second common layer may be formed using the third mask. In addition, in the above-described manufacturing method, the first common layer may be formed using a third mask, and the second common layer may be formed using a fourth mask. At this time, the aperture pattern of the third mask is shifted from the aperture pattern of the fourth mask by a distance corresponding to one pixel.

Further, one embodiment of the present invention is a method for manufacturing a display panel, including the steps of: forming a first pixel electrode, a second pixel electrode, and a third pixel electrode on the insulating surface; forming a first organic compound layer on the first pixel electrode and the second pixel electrode; forming a second organic compound layer on the third pixel electrode through a process different from the process of forming the first organic compound layer; and forming a common electrode on the first organic compound layer and the second organic compound layer. The first organic compound layer has a function of emitting light of the same color as the second organic compound layer.

In the above-described manufacturing method, the first organic compound layer may be formed using a first mask, the first mask may be moved parallel to the insulating surface by a distance equivalent to one pixel after the first organic compound layer is formed, and then the second organic compound layer may be formed using the first mask. In addition, in the above-described manufacturing method, the first organic compound layer may be formed using a first mask, and the second organic compound layer may be formed using a second mask. At this time, the aperture pattern of the first mask is shifted from the aperture pattern of the second mask by a distance corresponding to one pixel.

In the above-described manufacturing methods, the auxiliary wiring may be formed through a step of forming the first pixel electrode, the second pixel electrode, and the third pixel electrode.

According to one embodiment of the present invention, display unevenness or luminance unevenness of a display panel or a display device can be suppressed. According to one embodiment of the present invention, a display panel or a display device with high display quality can be provided. According to one embodiment of the present invention, a display panel or a display device with a high aperture ratio of pixels can be provided. According to one embodiment of the present invention, a display panel or a display device with high reliability can be provided.

According to one embodiment of the present invention, a display device can be increased in size. According to one embodiment of the present invention, a display device having a large display area in which a seam is not easily visible can be provided. According to one embodiment of the present invention, the display device can be made thin or light. According to one embodiment of the present invention, a display device capable of displaying along a curved surface can be provided. According to one embodiment of the present invention, a display device having excellent visibility can be provided. According to an embodiment of the present invention, a novel display panel or display device can be provided.

Note that the description of the above effects does not hinder the existence of other effects. An embodiment of the present invention does not necessarily need to have all of the above-described effects. The effects other than the above effects can be derived from the description of the specification, the drawings, and the claims.

Drawings

In the drawings:

fig. 1A is a plan view showing an example of a display panel, and fig. 1B and 1C are sectional views showing an example of a display panel;

fig. 2A and 2B are plan views illustrating examples of the display panel, and fig. 2C and 2D are sectional views illustrating examples of the display panel;

fig. 3A to 3E are sectional views showing one example of a manufacturing method of a display panel;

fig. 4A to 4C are plan views showing an example of a manufacturing method of a display panel;

fig. 5A to 5D are sectional views showing an example of a manufacturing method of a display panel;

fig. 6A to 6C are sectional views showing one example of a manufacturing method of a display panel;

fig. 7A and 7C are plan views showing an example of a display panel, and fig. 7B is a sectional view showing an example of a display panel;

fig. 8A and 8B are plan views showing examples of pixels;

fig. 9A and 9C are plan views showing a display panel of a comparative example, and fig. 9B is a sectional view showing the display panel of the comparative example;

fig. 10A is a plan view showing an example of a display panel, and fig. 10B is a sectional view showing an example of a display panel;

fig. 11 is a sectional view showing one example of a display panel;

fig. 12A is a plan view showing an example of a display panel, and fig. 12B and 12C are perspective views showing a configuration example of the display panel;

fig. 13A and 13B are plan views showing examples of the display panel. Fig. 13C is a sectional view showing an example of a display panel;

fig. 14 is a sectional view showing one example of a display device;

fig. 15A to 15D are plan views showing one example of a display panel;

fig. 16A and 16B are sectional views showing examples of display panels;

fig. 17A is a plan view showing an example of the display panel, and fig. 17B is a sectional view showing an example of the display panel.

Fig. 18A, 18B1, 18B2, 18C1, and 18C2 are sectional views showing an example of a manufacturing method of a display panel;

fig. 19A and 19B are sectional views showing one example of a transistor;

fig. 20A is a block diagram of an example of a pixel, and fig. 20B is a diagram showing an example of a pixel;

fig. 21A and 21B are timing charts showing an example of the operation of the pixel;

fig. 22A to 22D are diagrams showing examples of electronic apparatuses;

fig. 23 is a sectional STEM image of the connection portion;

fig. 24A to 24F are sectional views showing an example of a manufacturing method of a display panel;

fig. 25A and 25B are sectional STEM images of the auxiliary wiring;

fig. 26A is a sectional view showing an example of a display panel, and fig. 26B is a plan view showing an example of a display panel;

fig. 27A to 27C are sectional STEM images of the connection portion;

fig. 28A and 28B are perspective views showing samples of a preservation test of a panel, and fig. 28C to 28F are diagrams showing results of the preservation test of a display panel;

fig. 29A, 29B, 29C1, and 29D are photographs showing an example of a method of bonding a display panel, fig. 29C2 is a side view showing an example of a method of bonding a display panel, and fig. 29E is a photograph showing a display panel;

fig. 30 is a side view showing an example of a display device;

fig. 31A and 31B are photographs showing a display device of the embodiment;

fig. 32 is a rear view showing an example of a display device;

fig. 33A and 33C are bottom views showing examples of the display panel, fig. 33B and 33D are top views showing examples of the display panel, and fig. 33E is a side view showing one example of the display device;

fig. 34A to 34C are photographs showing a display device of the embodiment;

fig. 35 is a diagram showing the estimation result of the aperture ratio of the pixel;

fig. 36A and 36B are perspective views showing a display device of the embodiment;

fig. 37A to 37D are photographs showing the display device of the embodiment.

Detailed Description

The embodiments are described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following description, and those skilled in the art can easily understand that the mode and details thereof can be changed into various forms without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments shown below.

Note that in the following description of the present invention, the same reference numerals are used in common in different drawings to denote the same portions or portions having the same functions, and repetitive description thereof will be omitted. Further, the same hatching is sometimes used when portions having the same function are displayed, and no reference numeral is particularly attached.

For convenience of understanding, the positions, sizes, ranges, and the like of the respective components shown in the drawings may not show the actual positions, sizes, ranges, and the like. Accordingly, the disclosed invention is not necessarily limited to the positions, sizes, ranges, etc., disclosed in the drawings.

In addition, the "film" and the "layer" may be exchanged with each other depending on the situation or state. For example, the "conductive layer" may be converted into a "conductive film". Further, the "insulating film" may be converted into an "insulating layer".

(embodiment mode 1)

In this embodiment, a display panel and a display device according to one embodiment of the present invention will be described with reference to fig. 1A to 18A, 18B1, 18B2, 18C1, and 18C 2.

The display panel of this embodiment mode is a display panel having a top emission structure including a light-emitting element as a display element.

Specifically, one embodiment of the present invention is a display panel including a first pixel electrode, a second pixel electrode, a third pixel electrode, a first light-emitting layer, a second light-emitting layer, a third light-emitting layer, a first common layer, a second common layer, a common electrode, and an auxiliary wiring. The first light emitting layer is positioned on the first pixel electrode. The second light emitting layer is positioned on the second pixel electrode. The third light emitting layer is positioned on the third pixel electrode. The first light-emitting layer has a function of emitting light of a different color from the second light-emitting layer. The first light-emitting layer has a function of emitting light of the same color as the third light-emitting layer. The first common layer is located on the first pixel electrode and the second pixel electrode. The first common layer has a portion overlapping with the first light-emitting layer and a portion overlapping with the second light-emitting layer. The second common layer is on the third pixel electrode. The second common layer has a portion overlapping with the third light emitting layer. The common electrode has a portion overlapping the first pixel electrode with the first common layer and the first light-emitting layer interposed therebetween, a portion overlapping the second pixel electrode with the first common layer and the second light-emitting layer interposed therebetween, a portion overlapping the third pixel electrode with the second common layer and the third light-emitting layer interposed therebetween, and a portion in contact with the top surface of the auxiliary wiring.

By connecting the auxiliary wiring to the common electrode of the light-emitting element, voltage drop due to resistance of the common electrode can be suppressed, and a display panel with high display quality can be realized. By dividing the common layer of the light emitting element into the first common layer and the second common layer, the aperture ratio of the pixel can be increased. Therefore, the reduction of the aperture ratio of the pixel due to the provision of the auxiliary wiring in the pixel portion of the display panel can be suppressed. The higher the aperture ratio of a pixel, the lower the luminance of the sub-pixel required to obtain a given luminance in the display panel. This makes it possible to prolong the life of the light-emitting element. In addition, the display panel can realize high luminance.

[ comparative example of display Panel ]

A display panel including auxiliary wirings as a comparative example will be described with reference to fig. 9A to 9C. Fig. 9A is a plan view of the pixel electrode 111 and the auxiliary wiring 120 included in the display panel. Fig. 9B shows a sectional view along the chain line X-Y shown in fig. 9A.

As shown in fig. 9A, the auxiliary wiring 120 of the common electrode 113 and the pixel electrode 111 may be provided on the same surface (the insulating layer 101 in fig. 9B) as shown in fig. 9B, an opening portion of the insulating layer 104 is formed on the auxiliary wiring 120, and all the E L layers 112 are formed by coating respectively according to colors, whereby the auxiliary wiring 120 and the common electrode 113 can be connected in the connection portion 122.

Here, a case where one pixel 130 is composed of three subpixels of red, green, and blue (R, G, B) is considered, when it is desired to form all the E L layers 112 by applying color respectively, the number of deposition processes is very large, and therefore, when the light emitting layers are formed by applying color respectively, it is preferable to form layers which can have a common structure among the subpixels of three colors, among the hole injection layer, the hole transport layer, the electron transport layer, and the electron injection layer, etc., in the same process.

Fig. 9C shows an example of a metal mask that can be used in the formation of the E L layer 112 by using the mask 150, a layer (common layer) having a common structure between three sub-pixels can be simultaneously formed, and the E L layer 112 is not formed in the connection portion 122, however, when using a mask, blurring or misalignment of a pattern occurs due to deposition of an evaporation material in a shadow region of the mask, and therefore, a large non-opening portion of the mask 150 (refer to a width W1 of the non-opening portion in fig. 9C) exists between two pixels 130 to prevent the E L layer 112 from being formed in the connection portion 122, and thus the aperture ratio of the mask 150 becomes low.

In this case, in one embodiment of the present invention, the common layer included in the E L layer is formed twice, and thus the aperture ratio of the pixel can be higher than that in the case where the common layer is formed once, and therefore, even if the auxiliary wiring is provided in the pixel portion of the display panel, the aperture ratio of the pixel can be suppressed from decreasing.

[ concrete example 1 of display Panel ]

A display panel including auxiliary wirings according to an embodiment of the present invention will be described with reference to fig. 1A to 7C.

Fig. 1A, 2A, and 2B each show a top view of a common layer 161A and a common layer 161B included in the display panel. Fig. 2A and 2B can be said to be a modification example of fig. 1A. FIG. 1B shows a cross-sectional view along the dotted line A1-A2 shown in FIG. 1A. FIG. 1C shows a cross-sectional view along the dotted line A11-A12 shown in FIG. 1A. FIG. 2C shows a cross-sectional view along the dotted line A3-A4 shown in FIG. 2A. FIG. 2D shows a cross-sectional view along the dotted line A5-A6 shown in FIG. 2A.

As shown in fig. 1A, fig. 1B is a cross-sectional view of a red sub-pixel R and a green sub-pixel G included in a pixel 130a, and a blue sub-pixel B included in a pixel 130B adjacent to the pixel 130 a. Fig. 1C is a cross-sectional view of a red subpixel R and a green subpixel G included in the pixel 130a, and a red subpixel R included in the pixel 130C adjacent to the pixel 130 a.

The display panel shown in fig. 1B includes a pixel electrode 111 and an auxiliary wiring 120 over an insulating layer 101, an end portion of the pixel electrode 111 and an end portion of the auxiliary wiring 120 are covered with an insulating layer 104, an E L layer is provided over the pixel electrode 111 through an opening of the insulating layer 104, a common electrode 113 is provided over the auxiliary wiring 120 and the E L layer, and the common electrode 113 is shared between sub-pixels of a plurality of colors or even between a plurality of pixels.

The E L layer includes a common layer (the common layer 161 and the common layer 165 in fig. 1B) shared by sub-pixels of a plurality of colors and a layer (the light-emitting layer 163 in fig. 1B) provided for each color, note that the common layer 161a and the common layer 161B are sometimes collectively referred to as the common layer 161, similarly, the light-emitting layer included in each sub-pixel is sometimes collectively referred to as the light-emitting layer 163, and the common layer 165a and the common layer 165B are sometimes collectively referred to as the common layer 165.

In this embodiment mode, an example is shown in which the light-emitting element includes the common layer 161 between the pixel electrode 111 and the light-emitting layer 163 and the common layer 165 between the light-emitting layer 163 and the common electrode 113, but the light-emitting element may include only one of the common layer 161 and the common layer 165.

As shown in fig. 1A to 1C, a plurality of light emitting elements in the same pixel include the same common layer 161 (common layer 161A or 161b), one of two light emitting elements in adjacent pixels includes the common layer 161A, and the other of two light emitting elements in adjacent pixels includes the common layer 161 b.

When a voltage higher than the threshold voltage of the light-emitting element is applied between the pixel electrode 111 and the common electrode 113, holes are injected into the E L layer from the anode side, and electrons are injected into the E L layer from the cathode side, the injected electrons and holes are recombined in the E L layer, and a light-emitting substance included in the E L layer emits light.

The auxiliary wiring 120 is in contact with the common electrode 113 in the connection portion 122. That is, the auxiliary wiring 120 is electrically connected to the common electrode 113. Since the common electrode 113 is electrically connected to the auxiliary wiring 120, a voltage drop due to the resistance of the common electrode 113 can be suppressed. This can suppress the luminance unevenness of the display panel and improve the display quality of the display panel. Note that the auxiliary wiring 120 does not overlap with the pixel electrode 111. In addition, the auxiliary wiring 120 is electrically insulated from the pixel electrode 111.

In the pixel 130a and the pixel 130d, the red subpixel R includes the light-emitting element 110R shown in fig. 1B. The light-emitting element 110R includes a pixel electrode 111, a common layer 161a, a light-emitting layer 163R, a common layer 165a, and a common electrode 113. On the other hand, in the pixels 130b and 130C, the light-emitting element included in the red sub-pixel R does not include the common layer 161a and the common layer 165a, but includes the common layer 161b and the common layer 165b (see fig. 1C).

In the pixel 130a and the pixel 130d, the green sub-pixel G includes the light-emitting element 110G shown in fig. 1B. The light-emitting element 110G includes a pixel electrode 111, a common layer 161a, a light-emitting layer 163G, a common layer 165a, and a common electrode 113. On the other hand, in the pixels 130b and 130c, the light-emitting element included in the green sub-pixel G does not include the common layer 161a and the common layer 165a, but includes the common layer 161b and the common layer 165 b.

In the pixel 130B and the pixel 130c, the sub-pixel B of blue includes the light emitting element 110B shown in fig. 1B. The light-emitting element 110B includes a pixel electrode 111, a common layer 161B, a light-emitting layer 163B, a common layer 165B, and a common electrode 113. On the other hand, in the pixel 130a and the pixel 130d, the light-emitting element included in the sub-pixel B for blue does not include the common layer 161B and the common layer 165B, but includes the common layer 161a and the common layer 165 a.

The common layer 161a and the common layer 161b are in contact in the region 170. Likewise, common layer 165a and common layer 165b are in contact in region 170. The common layer 165a is in contact with the common layer 161a in the region 170. Likewise, the common layer 165b is in contact with the common layer 161b in the region 170.

As shown in fig. 1A, the region where the common layer 161A and the common layer 161b are not provided is only the connection portion 122 and its periphery. In other words, it can be said that the plurality of regions of the common layer 161 are not provided so as to exist separately from each other. When the common layer 161 is formed at one time using a metal mask, it is structurally difficult to form a plurality of regions where the common layer 161 is not formed separately from each other. Therefore, it can be said that the top surface layout of the common layer 161 shown in fig. 1A is a unique layout obtained by forming the common layer 161 in multiple times, that is, a unique layout of one embodiment of the present invention.

Note that, due to misalignment of a mask during film formation, as shown in fig. 2A to 2D, a portion where the common layer 161a and the common layer 161b overlap and a portion where the common layer 161a and the common layer 161b are separated may occur.

Fig. 2A illustrates an example in which the common layer 161a included in the pixel 130a overlaps the common layer 161b included in the pixel 130b, and the common layer 161b included in the pixel 130c is separated from the common layer 161a included in the pixel 130 d.

In the region 171 shown in fig. 2C, the common layer 161b is located on the common layer 161 a. Likewise, in region 171, common layer 165b is located on common layer 165 a.

In the region 172 shown in fig. 2D, the common layer 161a and the common layer 161b are separated. Likewise, in region 172, common layer 165a and common layer 165b are separated.

In fig. 2B, the common layer 161a included in each of the pixels 130a and 130d overlaps the common layer 161B included in the pixel 130B, and is separated from the common layer 161B included in the pixel 130 c.

In fig. 2A and 2B, the common layer 161a and the common layer 161B are not provided in the connection portion 122 and the periphery thereof. That is, a plurality of regions where the common layer 161 is not provided exist separately from each other. Therefore, it can be said that the top surface layout of the common layer 161 shown in fig. 2A and 2B is also a unique layout obtained by forming the common layer 161a plurality of times, that is, a unique layout of an embodiment of the present invention.

Note that in fig. 1B, 2C, and 2D, an example in which the end portion of the common layer 161 and the end portion of the common layer 165 are aligned is shown, but not limited thereto.

Since the display panel of one embodiment of the present invention has a top emission structure, the pixel electrode 111 is an electrode on the side where light is not extracted. The pixel electrode 111 preferably includes a conductive film that reflects visible light. When the light emitting element adopts an optical microcavity resonator (microcavity) structure, the pixel electrode 111 is preferably a reflective electrode. The reflectance of the reflective electrode with respect to visible light is 40% to 100%, preferably 70% to 100%.

In the display panel according to the embodiment of the present invention, the pixel electrode 111 and the auxiliary wiring 120 can be manufactured by processing the same conductive film. The resistivity of the material for the pixel electrode 111 and the auxiliary wiring 120 is preferably lower than the resistivity of the material for the common electrode 113.

The conductive film that reflects visible light may be formed using a metal material such as aluminum, gold, platinum, silver, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, or palladium, or an alloy containing such a metal material, and further, lanthanum, neodymium, or germanium may be added to the metal material or alloy.

The E L layer includes at least a light-emitting layer, the E L layer may include a plurality of light-emitting layers, the E L layer may include a layer including a substance having a high hole injecting property, a substance having a high hole transporting property, a hole-blocking material, a substance having a high electron transporting property, a substance having a high electron injecting property, a bipolar substance (a substance having a high electron transporting property and a high hole transporting property), or the like in addition to the light-emitting layer, the E L layer includes one or a plurality of light-emitting substances, and the light-emitting substance may be an organic compound or an inorganic compound.

The common layer 161 preferably includes a hole injection layer. The common layer 161 may further include a hole transport layer. The common layer 165 preferably includes an electron injection layer. The common layer 165 may further include an electron transport layer.

The hole injection layer is a layer for injecting holes from the anode into the layer E L and is a layer containing a material having a high hole-injecting property.

The hole transport layer is a layer that transports holes injected from the anode through the hole injection layer to the light-emitting layer, and is a layer containing a hole-transporting material.

The light-emitting layer is a layer containing a light-emitting substance. As the light-emitting substance, a substance exhibiting a light-emitting color such as blue, violet, bluish-violet, green, yellowish green, yellow, orange, or red is suitably used. Further, by using different light-emitting substances in each of the plurality of light-emitting layers, a structure in which different light-emitting colors are present can be obtained (for example, white light can be obtained by combining light-emitting colors in a complementary color relationship). Further, a stacked structure in which one light-emitting layer includes different light-emitting substances may be employed. The light-emitting substance that can be used in the light-emitting layer is not particularly limited, and a light-emitting substance that converts singlet excitation energy into light in the visible light region or a light-emitting substance that converts triplet excitation energy into light in the visible light region can be used. As a light-emitting substance which converts a single excitation energy into light emission, a substance which emits fluorescence (fluorescent material) can be given. Examples of the light-emitting substance which converts triplet excitation energy into light emission include a substance which emits phosphorescence (phosphorescent material) and a Thermally Activated Delayed Fluorescence (TADF) material which exhibits thermally activated delayed fluorescence. When a light-emitting substance that converts singlet excitation energy into light in the visible light region is used as the blue light-emitting substance and a light-emitting substance that converts triplet excitation energy into light in the visible light region is used as the green and red light-emitting substances, the balance of the RGB spectra is favorably exhibited. In addition, the light-emitting layer may contain one or more compounds (host material and assist material) in addition to the light-emitting substance (guest material). As the host material and the auxiliary material, one or more kinds of substances having a larger energy gap than that of the light-emitting substance (guest material) are used. As the host material and the auxiliary material, a compound forming an exciplex is preferably used in combination. In order to efficiently form an exciplex, it is particularly preferable to combine a compound which easily accepts holes (hole-transporting material) and a compound which easily accepts electrons (electron-transporting material).

The electron transport layer is a layer that transports electrons injected from the cathode by the electron injection layer to the light emitting layer, and is a layer containing an electron transporting material.

The electron injection layer is a layer that injects electrons from the cathode into the E L layer, and is a layer containing a material having a high electron injection property.

When the light-emitting element has a microcavity structure, optical adjustment can be performed using an electrode or an E L layer, and when optical adjustment is performed using at least one of the layers constituting the E L layer, the layers may be provided separately for each color, similarly to the light-emitting layer.

The E L layer may be formed using any of a low-molecular compound and a high-molecular compound, or may contain an inorganic compound (such as a quantum dot material), and the layer constituting the E L layer may be formed by a method such as vapor deposition (including vacuum vapor deposition), transfer, printing, inkjet, or coating.

The light-emitting element may be a single element including one E L layer, or may be a series element in which a plurality of E L layers are stacked with a charge generation layer interposed therebetween.

In one embodiment of the present invention, a light-emitting element using an inorganic compound such as a quantum dot may be used.

The common electrode 113 is an electrode on the light extraction side. The common electrode 113 preferably includes a conductive film that transmits visible light. When the light emitting element adopts a microcavity structure, the common electrode 113 preferably has visible light transmittance and visible light reflectance. The reflectance of the semi-transmissive/semi-reflective electrode with respect to visible light is 20% or more and 80% or less, preferably 40% or more and 70% or less.

The conductive film that transmits visible light can be formed using, for example, indium oxide, ITO, indium zinc oxide, zinc oxide (ZnO), gallium zinc oxide (Ga — Zn oxide), aluminum zinc oxide (Al — Zn oxide), or the like. Further, a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, an alloy containing such a metal material, or a nitride (e.g., titanium nitride) of such a metal material may be formed to be thin so as to have light-transmitting properties. Further, a stacked film of the above materials can be used as the conductive film. For example, a laminated film of an alloy of silver and magnesium and ITO is preferably used because the conductivity can be improved. In addition, graphene or the like may also be used.

The pixel electrode 111 and the common electrode 113 can be formed by an evaporation method or a sputtering method. In addition, the ink can be formed by an ejection method such as an ink jet method, a printing method such as a screen printing method, or a plating method.

A method for manufacturing the display panel shown in fig. 1B will be described with reference to fig. 3A to 6C.

Thin films (an insulating film, a semiconductor film, a conductive film, and the like) constituting the display panel can be formed by a sputtering method, a Chemical Vapor Deposition (CVD) method, a vacuum evaporation method, a pulsed laser deposition (P L D) method, an atomic layer deposition (a L D) method, or the like.

The thin films (insulating films, semiconductor films, conductive films, and the like) constituting the display panel can be formed by a method such as a spin coating method, a dipping method, a spray coating method, an ink jet method, a dispensing method, a screen printing method, an offset printing method, a doctor blade method, a slit coating method, a roll coating method, a curtain coating method, or a doctor blade coating method.

When a thin film constituting a display panel is processed, the processing may be performed by photolithography or the like. In addition, the island-shaped thin film may be formed by a deposition method using a shadow mask. In addition, the thin film can be processed by a nanoimprint method, a sandblast method, a peeling method, or the like. The following methods are used in photolithography: a method of forming a resist mask on a thin film to be processed and removing the resist mask by processing the thin film by etching or the like; a method in which a photosensitive film is formed, and then the film is processed into a desired shape by exposure and development.

When light is used in the photolithography, for example, i-line (wavelength 365nm), g-line (wavelength 436nm), h-line (wavelength 405nm), or a mixture of these lights can be used as the light used for exposure. In addition, ultraviolet rays, KrF laser, ArF laser, or the like can be used. Further, exposure may be performed by an immersion exposure technique. As the light for exposure, Extreme Ultraviolet (EUV) or X-ray may also be used. In addition, an electron beam may be used instead of the light for exposure. When extreme ultraviolet rays, X-rays, or electron beams are used, extremely fine processing can be performed, and therefore, such is preferable. Note that a photomask is not required when exposure is performed by scanning or the like with a beam such as an electron beam.

As a method for etching the thin film, a dry etching method, a wet etching method, a sandblasting method, or the like can be used.

First, a conductive film 131 is formed over the insulating layer 101 (fig. 3A).

Next, the conductive film 131 is processed, whereby the pixel electrode 111 and the auxiliary wiring 120 are formed over the insulating layer 101 (fig. 3B). Next, the insulating layer 104 is formed so as to cover the end portion of the pixel electrode 111 and the end portion of the auxiliary wiring 120 (fig. 3C). An opening is formed in the insulating layer 104 to expose the top surface of the pixel electrode 111 and the top surface of the auxiliary wiring 120.

The common layer 161a is formed using the mask 155 (fig. 3C, 4A). As shown in fig. 4A, the mask 155 is formed with openings so as to form a common layer 161a every other pixel in the column direction and the row direction. When the common layer 161a is formed in the pixel 130a shown in fig. 4A, the common layer 161a is not formed in four pixels adjacent to the pixel 130 a. For example, the common layer 161a is formed in a region corresponding to the pixel 130a and the pixel 130d, but is not formed in a region corresponding to the pixel 130b, the pixel 130c, and the connection portion 122. Mask 155 is preferably a metal mask.

The mask 155 is moved parallel to the insulating layer 101 by a distance corresponding to one pixel. The direction of moving the mask 155 is a direction which may be either a column direction in the pixel arrangement or a row direction in the pixel arrangement.

The common layer 161B is formed using the mask 155 (fig. 3D and 4B). As shown in fig. 4B, the common layer 161B is formed in a pixel where the common layer 161a is not formed by shifting the mask 155 by a distance corresponding to one pixel. For example, the common layer 161b is formed in a region corresponding to the pixel 130b and the pixel 130c, but is not formed in a region corresponding to the pixel 130a, the pixel 130d, and the connection portion 122.

Note that, in the formation of the common layer 161b, another mask having an opening pattern shifted by a distance corresponding to one pixel from the opening pattern of the mask 155 may be used.

As shown in fig. 4C, by forming the common layer 161 in two times, the common layer 161 can be formed in all the pixels and not in the connection portion 122. By forming the common layer 161 twice, the aperture ratio of the pixel can be higher than the case where the common layer 161 is formed once.

Next, the light-emitting layer 163B, the light-emitting layer 163G, and the light-emitting layer 163R are formed in different steps (fig. 3E and 5A). There is no limitation on the order of formation of the light emitting layer. Fig. 3E shows an example in which the light-emitting layer 163B is formed first. By forming the layer from a color having a short wavelength, even if a light-emitting material or the like unintentionally enters a pixel of another color, a display defect may be less likely to occur.

Further, layers other than the light-emitting layer may be formed according to colors. For example, after a hole injection layer is formed as the common layer 161, a hole transport layer and a light emitting layer may be formed according to colors. In this case, by continuously forming the hole transport layer and the light-emitting layer, the reliability of the light-emitting element can be improved. Specifically, as shown in fig. 6A, the blue light-emitting layer 163B _2 is formed after the blue hole transport layer 163B _1 is formed, then, as shown in fig. 6B, the green light-emitting layer 163G _2 is formed after the green hole transport layer 163G _1 is formed, and then, as shown in fig. 6C, the red light-emitting layer 163R _2 is formed after the red hole transport layer 163R _1 is formed. The hole transport layer can be provided with an optical adjustment function by making the thickness of the hole transport layer different depending on the color.

The common layer 165a is formed using the mask 155 (fig. 5B). The common layer 165a is formed in the regions corresponding to the pixels 130a and 130d, and is not formed in the regions corresponding to the pixels 130b, 130c, and the connection portion 122, as in the common layer 161 a.

The mask 155 is moved by a distance equivalent to one pixel and in parallel to the insulating layer 101.

The common layer 165b is formed using the mask 155 (fig. 5C). The common layer 165b is formed in the regions corresponding to the pixels 130b and 130c, and is not formed in the regions corresponding to the pixels 130a, 130d, and the connection portion 122, as in the common layer 161 b.

Note that, in the formation of the common layer 165b, another mask having an opening pattern which is shifted from the opening pattern of the mask 155 by a distance corresponding to one pixel may be used.

Then, the common electrode 113 is formed so as to cover the auxiliary wiring 120, the common layer 165a, and the common layer 165b (fig. 5D). Thereby, the auxiliary wiring 120 and the common electrode 113 are connected in the connection portion 122.

As described above, not only the light emitting layers 163 are formed separately according to colors, but also the common layer 161 and the common layer 165 are formed in two times, whereby the aperture ratio of the pixel can be made higher than in the case where the common layer is formed at one time. Therefore, even if the auxiliary wiring 120 is provided in the pixel portion of the display panel, the aperture ratio of the pixel of the display panel can be increased. Therefore, the luminance of the sub-pixel required for obtaining the predetermined luminance of the display panel can be reduced, and the lifetime of the light emitting element can be extended. Further, since the width of the non-opening portion of the mask 155 can be sufficiently secured, a sufficiently large tension can be applied to the mask 155, and the accuracy of the mask 155 can be improved.

The E L layer may also comprise all layers that are common to multiple color sub-pixels.

Fig. 7A illustrates a top view of the E L layer 112a and the E L layer 112B included in the display panel, and fig. 7B illustrates a cross-sectional view along the chain line a7-a8 illustrated in fig. 7A.

As shown in fig. 7A, fig. 7B is a cross-sectional view of a sub-pixel R including red and a sub-pixel G including green included in the pixel 130a, and a sub-pixel B including blue included in the pixel 130B adjacent to the pixel 130 a.

In the display panel shown in fig. 7B, the pixel electrode 111 and the auxiliary wiring 120 are provided over the insulating layer 101, the end of the pixel electrode 111 and the end of the auxiliary wiring 120 are covered with the insulating layer 104, the E L layer 112a or the E L layer 112B is provided over the pixel electrode 111 through the opening of the insulating layer 104, the common electrode 113 is provided over the auxiliary wiring 120 and the E L layer 112a or the E L layer 112B, the auxiliary wiring 120 and the common electrode 113 are in contact with each other at the connection portion 122, that is, the auxiliary wiring 120 and the common electrode 113 are electrically connected, the pixel electrode 111 overlaps the common electrode 113 with the E L layer 112a or the E L layer 112B interposed therebetween, the colored layer CFR, the colored layer CFG, the colored layer CFB, and the light-shielding layer BM are located on one surface side of the counter substrate 121, and a polarizing plate such as a hard substrate, a film substrate.

In the pixels 130a and 130d, the red sub-pixel R includes the light-emitting element 110R shown in fig. 7B the light-emitting element 110R includes the pixel electrode 111, the E L layer 112a, and the common electrode 113, light from the light-emitting element 110R is extracted to the counter substrate 121 side through the coloring layer CFR, and on the other hand, in the pixels 130B and 130c, the light-emitting element included in the red sub-pixel R includes not the E L layer 112a but the E L layer 112B.

In the pixels 130a and 130d, the green sub-pixel G includes the light-emitting element 110G shown in fig. 7B, the light-emitting element 110G includes the pixel electrode 111, the E L layer 112a, and the common electrode 113, light from the light-emitting element 110G is extracted to the counter substrate 121 side through the coloring layer CFG, and on the other hand, in the pixels 130B and 130c, the light-emitting element included in the green sub-pixel G does not include the E L layer 112a and includes the E L layer 112B.

In the pixels 130B and 130c, the sub-pixel B of blue includes the light-emitting element 110B shown in fig. 7B, the light-emitting element 110B includes the pixel electrode 111, the E L layer 112B, and the common electrode 113, light from the light-emitting element 110B is extracted to the counter substrate 121 side through the coloring layer CFB, and on the other hand, in the pixel 130a and the pixel 130d, the light-emitting element included in the sub-pixel B of blue includes not the E L layer 112B but the E L layer 112 a.

The light-emitting elements included in the sub-pixels of each color preferably emit white light.

The E L layer 112A and the E L layer 112b are in contact in the region 170, similarly to the structure shown in fig. 2A to 2D, a portion where the E L layer 112A and the E L layer 112b overlap and a portion where the E L layer 112A and the E L layer 112b are separated are sometimes generated due to misalignment of a mask at the time of deposition or the like.

Depending on the size of the opening of the mask 155, the common layer 161a and the common layer 161b may not be in contact. Even in such a case, it is possible to determine whether the common layer 161 is formed at one time or at a plurality of times. For example, a slight shift may occur between the position of the common layer 161a formed in the first step and the position of the common layer 161b formed in the second step. Therefore, as shown in fig. 7C, a difference may occur between a distance Wa between the common layer 161a included in the pixel 130a and the common layer 161b included in the pixel 130b and a distance Wb between the common layer 161a included in the pixel 130d and the common layer 161b included in the pixel 130C. By forming the common layer 161 in two times in this manner, a unique layout in which the pitch of the common layer 161 is different for each column or each row is sometimes obtained. As described above, depending on the pitch of the common layer 161, it may be confirmed that the common layer 161 is formed in a plurality of times.

Note that when the E L layer includes a layer having high conductivity, a current may leak to an adjacent light-emitting element through the layer having high conductivity, and light-emitting elements other than a desired light-emitting element emit light (also referred to as a crosstalk phenomenon).

Note that the arrangement of the sub-pixels is not limited to the structure of fig. 1A, but the structure of fig. 1A can improve the aperture ratio, and is therefore preferable. Fig. 8A and 8B show an arrangement of sub-pixels different from that of fig. 1A. Fig. 8A shows an example of a stripe arrangement, and fig. 8B shows an example of a matrix arrangement. In addition to this, as the arrangement of the sub-pixels, an S stripe arrangement, a PenTile arrangement, a bayer arrangement, or the like can be employed.

The colored layer is a colored layer that transmits light in a specific wavelength region. For example, a color filter or the like that transmits light in a wavelength region of red, green, blue, or yellow may be used. Examples of materials that can be used for the colored layer include metal materials, resin materials, and resin materials containing pigments or dyes.

The light-shielding layer BM is provided between adjacent colored layers. The light-shielding layer BM shields light emitted from adjacent light-emitting elements, thereby suppressing color mixing between the adjacent light-emitting elements. Here, by providing the colored layer so that the end portion thereof overlaps the light-shielding layer BM, light leakage can be suppressed. The light-shielding layer BM may be formed of a material that shields light emitted from the light-emitting element, and may be formed of, for example, a metal material or a resin material containing a pigment or a dye. Further, when the light-shielding layer BM is provided in a region other than the pixel portion of the driver circuit or the like, unintended light leakage due to waveguide light or the like can be suppressed, which is preferable.

[ concrete example 2 of display Panel ]

Fig. 10A shows a top view of the display panel 10A. Fig. 10B illustrates a cross-sectional view of the display panel 10A. Fig. 10B corresponds to a sectional view taken along the chain line B1-B2 shown in fig. 10A.

The display panel 10A shown in fig. 10A includes a pixel portion 71 and a driver circuit 78. The display panel is connected with an FPC 74. A connector such as an fpc (flexible Printed circuit) or an IC (integrated circuit) may be connected to the display panel. For example, a display module may be manufactured by incorporating a scanning line driver circuit in a display panel and externally incorporating a signal line driver circuit.

The display panel 10A is a display panel having a top emission structure in a separate coating manner, since the display panel 10A includes the auxiliary wiring, it is possible to suppress a voltage drop caused by the resistance of the common electrode 113 to reduce display unevenness, and further, the common layer included in the E L layer is formed twice, and thus the aperture ratio of the pixel is high even if the display panel 10A includes the auxiliary wiring in the pixel portion 71.

As shown in fig. 10B, the display panel 10A includes a substrate 361, an insulating layer 367, a transistor 301, a transistor 303, a conductive layer 307, an insulating layer 314, a light-emitting element 20A, a light-emitting element 20B, a light-emitting element 21A, an insulating layer 104, a protective layer 109, an auxiliary wiring 120A, an auxiliary wiring 120B, an adhesive layer 318, a substrate 371, and the like.

Each of the light-emitting elements 20A, 20B, and 21A includes pixel electrodes 111A and 111B, an E L layer, and a common electrode 113.

The pixel electrode 111a is electrically connected to the source or drain of the transistor 303. They are connected directly or through other conductive layers.

The pixel electrodes 111B included in the light-emitting elements 20A, 20B, and 21A function as optical adjustment layers. When the microcavity structure is applied to a light-emitting element, light with high color purity can be extracted from the display panel. The structure of the pixel electrode is not limited to the stacked structure, and may have a single-layer structure.

The insulating layer 104 covers end portions of the pixel electrodes 111a and 111 b. Adjacent two pixel electrodes are electrically insulated by an insulating layer 104. The pixel electrode is also electrically insulated from the auxiliary wiring by the insulating layer 104.

The E L layer includes a common layer (the common layer 161 and the common layer 165 in fig. 10B) shared by sub-pixels of a plurality of colors and layers (the light-emitting layers 163 in fig. 10B) respectively provided according to colors here, the light-emitting element 20A shown in fig. 10B is included in the same pixel as the light-emitting element 20B and is included in a pixel different from the light-emitting element 21A the pixel including the light-emitting element 21A is adjacent to the pixel including the light-emitting element 20A both the light-emitting element 20A and the light-emitting element 20B included in the same pixel, the light-emitting element 21A included in a pixel adjacent to the pixel including these two light-emitting elements includes the common layer 161B and the common layer 165B in the region 172, the common layer 161A and the common layer 161B are separated, the common layer 165a and the common layer 165B are separated similarly, the light-emitting element 20A and the light-emitting element 21A include 163A, the light-emitting element 20B includes 163B, that the light-emitting element 20A includes a contact sub-emitting layer 113A and the common layer 113B, that is shown to be a contact with the pixel 20A, the pixel, the wiring 113B covers the end of the same color of the light-emitting element 113A and the end of the sub-emitting layer L, the wiring 113B is exposed outside the pixel, the sub-electrode 113B, the wiring L, and the wiring 113B is exposed at the end portion of the wiring L.

The protective layer 109 covers an end portion of the common electrode 113 and is in contact with the insulating layer 104 outside the end portion of the common electrode 113. The protective layer 109 covers the end portion of the insulating layer 314 and the end portion of the insulating layer 104 at the end portion of the display panel 10A and the vicinity thereof, and is in contact with the insulating layer 313 outside the end portion of the insulating layer 314 and the end portion of the insulating layer 104. In the various insulating layers and the protective layer 109 of the display panel of the present embodiment, the end portion of the inorganic film (or the inorganic insulating film) is preferably located outside the end portion of the organic film, and the inorganic films (or the inorganic insulating films) are preferably stacked in contact with each other at the end portion of the display panel and in the vicinity thereof. Accordingly, impurities such as moisture are less likely to enter from the outside of the display panel, and deterioration of the transistor and the light-emitting element can be suppressed.

The auxiliary wirings 120a and 120b are electrically connected to the common electrode 113 through the opening of the insulating layer 104. The auxiliary wiring 120a may be formed using the same material as the pixel electrode 111a in the same process as the pixel electrode 111 a. The auxiliary wiring 120b may be formed using the same material as the pixel electrode 111b in the same process as the pixel electrode 111 b.

Note that the auxiliary wiring of the common electrode 113 is not limited to being formed in the same process as the pixel electrode. The auxiliary wiring may be formed using the same material as at least one of the various wirings and electrodes included in the display panel, for example, in the same process as at least one of the various wirings and electrodes included in the display panel. By forming the auxiliary wiring in the same layer as the other conductive layers included in the display panel, the auxiliary wiring can be formed in the display panel without increasing the number of steps for forming the display panel. On the other hand, by forming the auxiliary wiring in a layer different from another conductive layer included in the display panel, the area of the auxiliary wiring can be increased, and thus voltage drop due to the resistance of the common electrode 113 can be more effectively suppressed.

Fig. 11 shows an example in which the auxiliary wiring 120 is formed using the same material as the source and the drain of the transistor in the same step as the source and the drain of the transistor.

In fig. 11, an example is shown in which all layers included in the E L layer are common layers shared by sub-pixels of a plurality of colors, the E L layer includes at least a light emitting layer, the light emitting element 20A is included in the same pixel as the light emitting element 20B and is included in a pixel different from the light emitting element 21A, a pixel including the light emitting element 21A is adjacent to a pixel including the light emitting element 20A, the light emitting element 20A and the light emitting element 20B included in the same pixel each include an E L layer 112a, the light emitting element 21A included in a pixel adjacent to a pixel including these two light emitting elements includes an E L1 layer 112B, in the region 172, the E L layer 112a and an E L layer 112B are separated, the end of the E L layer is covered with a common electrode 113, the common electrode 113 covers the end of the E L layer and is in contact with the insulating layer 104 outside of the end of the E L layer, and the common electrode 113 is in contact with the auxiliary wiring 120, fig. 11 shows an example in which the E5635 layer having a three-layer structure and the light emitting element 20A, the same color of the light emitting element 20A, the pixel 20A, the light emitting element 20B, and the light emitting element 20B, and the light emitting element 20B are included in the same color layer 20B.

As for the light-emitting element and the auxiliary wiring, the description of specific example 1 of the display panel can be referred to.

The display panel preferably includes a protective layer 109 covering the light emitting elements. By using a film having high barrier properties as the protective layer 109, impurities such as moisture and oxygen can be suppressed from entering the light-emitting element. This can suppress deterioration of the light-emitting element and improve the reliability of the display panel.

Since the light emission of the light-emitting element is extracted to the outside of the display panel through the protective layer 109, the protective layer 109 is preferably highly transparent to visible light.

The protective layer 109 preferably includes an inorganic film (or an inorganic insulating film). By covering the light-emitting element with the inorganic film, impurities such as moisture and oxygen that enter the light-emitting element from the outside can be suppressed. An organic compound or a metal material constituting a light-emitting element reacts with impurities to cause deterioration of the light-emitting element. Therefore, by adopting a structure in which impurities do not easily intrude into the light-emitting element, deterioration of the light-emitting element is suppressed, and reliability of the light-emitting element can be improved.

The inorganic film (or inorganic insulating film) preferably has high moisture resistance and makes water not easily diffuse and pass through. Further, the inorganic film (or inorganic insulating film) is preferably such that one or both of hydrogen and oxygen do not easily diffuse and pass through. Thereby, the inorganic film (or inorganic insulating film) can be made to function as a barrier film. Further, impurities diffusing from the outside to the light emitting element can be effectively suppressed, and a highly reliable display panel can be realized.

The protective layer 109 preferably includes 1 or more insulating films. As the protective layer 109, an oxide insulating film, a nitride insulating film, an oxynitride insulating film, a nitride oxide insulating film, or the like can be used. Examples of the oxide insulating film include a silicon oxide film, an aluminum oxide film, a gallium oxide film, a germanium oxide film, an yttrium oxide film, a zirconium oxide film, a lanthanum oxide film, a neodymium oxide film, a hafnium oxide film, a tantalum oxide film, and the like. Examples of the nitride insulating film include a silicon nitride film and an aluminum nitride film. Examples of the oxynitride insulating film include a silicon oxynitride film and the like. Examples of the oxynitride insulating film include a silicon oxynitride film and the like.

In this specification and the like, oxynitride refers to a material having more oxygen content than nitrogen content in its composition, and oxynitride refers to a material having more nitrogen content than oxygen content in its composition.

In particular, since the silicon nitride film, the silicon oxynitride film, and the aluminum oxide film have high moisture resistance, they are suitable for the protective layer 109.

Further, as the protective layer 109, an inorganic film containing ITO, Ga-Zn oxide, Al-Zn oxide, In-Ga-Zn oxide, or the like can be used. The inorganic film preferably has a high resistance, and specifically, the inorganic film preferably has a higher resistance than the common electrode 113. The inorganic membrane may also include nitrogen.

The protective layer 109 can be formed by a CVD method, a sputtering method, an a L D method, or the like, and two or more insulating films formed by different deposition methods may be stacked as the protective layer 109.

Since the E L layer included in the light-emitting element has low heat resistance, the protective layer 109 formed after the light-emitting element is manufactured is preferably formed at a relatively low temperature, typically 100 ℃.

The thickness of the inorganic film formed by the sputtering method is preferably 50nm or more and 1000nm or less, and more preferably 100nm or more and 300nm or less.

The thickness of the inorganic film formed by the a L D method is preferably 1nm or more and 100nm or less, and more preferably 5nm or more and 50nm or less.

The protective layer 109 has a water vapor transmission rate of less than 1 × 10^-2g/(m²Day), preferably 5 × 10^-3g/(m²Day), more preferably 1 × 10^-4g/(m²Day), more preferably 1 × 10^-5g/(m²Day), more preferably 1 × 10^-6g/(m²Day) below. The lower the water vapor transmission rate, the less the diffusion of water from the outside to the transistor and the light-emitting element can be reduced.

The thickness of the protective layer 109 is 1nm or more and 1000nm or less, preferably 50nm or more and 500nm or less, and more preferably 100nm or more and 300nm or less. The smaller the thickness of the insulating layer, the more the total thickness of the display panel can be reduced, and is therefore preferable. The smaller the thickness of the insulating layer, the more the yield can be improved, and thus the productivity of the display panel can be improved.

Examples of the organic insulating material that can be used for the insulating layer 104 include acrylic resin, epoxy resin, polyimide resin, polyamide resin, polyimide amide resin, polysiloxane resin, benzocyclobutene resin, and phenol resin. In addition, an inorganic insulating layer may be used instead of the insulating layer 104. The inorganic insulating layer may employ an inorganic insulating film that can be used for the protective layer 109.

When an inorganic insulating film is used as an insulating layer covering an end portion of the pixel electrode, impurities are less likely to enter the light-emitting element than in the case of using an organic insulating film, and reliability of the light-emitting element can be improved. When an organic insulating film is used as an insulating layer covering the end portion of the pixel electrode, the step coverage is high and is less likely to be affected by the shape of the pixel electrode than when an inorganic insulating film is used. Therefore, short-circuiting of the light emitting element can be prevented.

In addition, both the insulating layer 104 and the protective layer 109 may have a single-layer structure or a stacked-layer structure using one or both of an inorganic insulating film and an organic insulating film.

The substrate 361 and the substrate 371 are bonded by an adhesive layer 318. The space 105 sealed by the substrate 361, the substrate 371, and the adhesive layer 318 is preferably filled with an inert gas such as nitrogen or argon, or a resin.

The substrate 361 and the substrate 371 can be made of glass, quartz, resin, metal, alloy, semiconductor, or the like. A substrate on the side from which light is extracted from the light-emitting element is made of a material which transmits the light. As the substrate 361 and the substrate 371, flexible substrates are preferably used. As the substrate 361 or the substrate 371, a polarizing plate can be used.

When the circularly polarizing plate is superimposed on the display panel, a substrate having high optical isotropy is preferably used as a substrate included in the display panel. A substrate having high optical isotropy has a low birefringence (that is, a small amount of birefringence).

The absolute value of the retardation value of the substrate having high optical isotropy is preferably 30nm or less, more preferably 20nm or less, and still more preferably 10nm or less.

Examples of the film having high optical isotropy include a cellulose Triacetate (TAC) film, a cycloolefin polymer (COP) film, a cycloolefin copolymer (COC) film, and an acrylic film.

When a thin film is used as a substrate, there is a possibility that a shape change such as a wrinkle of a display panel occurs due to water absorption of the thin film. Therefore, a thin film having low absorption rate is preferably used as the substrate. For example, a film having an absorption rate of 1% or less is preferably used, a film having an absorption rate of 0.1% or less is more preferably used, and a film having an absorption rate of 0.01% or less is even more preferably used.

As the pressure-sensitive adhesive layer, various curable pressure-sensitive adhesives such as a photo-curable pressure-sensitive adhesive such as an ultraviolet curable pressure-sensitive adhesive, a reaction curable pressure-sensitive adhesive, a thermosetting pressure-sensitive adhesive, and an anaerobic pressure-sensitive adhesive can be used. Further, an adhesive sheet or the like may also be used.

The driver circuit 78 includes a transistor 301. The pixel portion 71 includes a transistor 303.

Each transistor includes a gate electrode, a gate insulating layer 311, a semiconductor layer, a back gate electrode, a source electrode, and a drain electrode. The gate electrode (the lower gate electrode in fig. 10B and 11) overlaps with the semiconductor layer with the gate insulating layer 311 interposed therebetween. The back gate (the upper gate in fig. 10B and 11) overlaps with the semiconductor layer with the insulating layer 312 and the insulating layer 313 interposed therebetween.

The transistors 301 and 303 each have a structure in which a semiconductor layer forming a channel is sandwiched between two gate electrodes. The transistor is preferably driven by connecting the two gates and supplying them with the same signal. Such a transistor can achieve a higher field effect mobility than other transistors, and thus can increase the on-current. As a result, a circuit capable of high-speed driving can be manufactured. Further, the occupied area of the circuit portion can be reduced. By using a transistor with a large on-current, signal delay of each wiring can be reduced even if the number of wirings is increased when a display panel or a display panel is increased in size or high definition, and display unevenness can be suppressed. Alternatively, the threshold voltage of the transistor can be controlled by applying a potential for controlling the threshold voltage to one of the two gates and applying a potential for driving to the other gate.

The driver circuit 78 and the pixel portion 71 may have different transistor structures from each other. The driver circuit 78 and the pixel portion 71 may each include a plurality of transistors.

By disposing a transistor, a capacitor, a wiring, and the like so as to overlap with a light-emitting region of the light-emitting element, the aperture ratio of the pixel portion 71 can be increased.

It is preferable to use a material in which impurities such as water or hydrogen do not easily diffuse for at least one of the insulating layer 312, the insulating layer 313, and the insulating layer 314. This can effectively suppress diffusion of impurities from the outside into the transistor, and can improve the reliability of the display panel. The insulating layer 314 is used as a planarization layer.

The insulating layer 367 functions as a base film. The insulating layer 367 is preferably made of a material in which impurities such as water and hydrogen do not easily diffuse.

The connection portion 306 includes a conductive layer 307. The conductive layer 307 can be formed using the same material and the same process as those of the source and the drain of the transistor. The conductive layer 307 is electrically connected to an external input terminal for transmitting a signal or a potential from the outside to the driver circuit 78. Here, an example is shown in which an FPC74 is provided as an external input terminal. The FPC74 and the conductive layer 307 are electrically connected by a connector 319.

As the connector 319, various Anisotropic Conductive Films (ACF), Anisotropic Conductive Paste (ACP), or the like can be used.

[ specific examples of display devices ]

Next, a display device including a plurality of display panels is described with reference to fig. 12A to 12C.

Fig. 12A shows a top view of the display panel DP. Fig. 12B and 12C illustrate perspective views of a display device including four display panels DP.

By arranging the plurality of display panels DP in one or more directions (for example, in a row, a matrix, or the like), a display device including a large display area can be manufactured.

In manufacturing a large-sized display device using a plurality of display panels DP, the size of one display panel DP does not need to be large. Therefore, the manufacturing apparatus for manufacturing the display panel DP may not be increased in size, and the space may be saved. Further, since the manufacturing apparatus for the small and medium-sized display panel can be used, it is not necessary to use a novel manufacturing apparatus in accordance with the increase in size of the display device, and the manufacturing cost can be suppressed. In addition, a decrease in yield accompanying an increase in size of the display panel DP can be suppressed.

In the case where the display panels DP have the same size, the display area of the display portion including the plurality of display panels DP is larger than that of the display portion including one display panel DP, thereby having effects of a larger amount of information that can be simultaneously displayed, and the like.

Here, a case where the display panel DP includes a non-display region so as to surround the pixel portion 71 is considered. For example, in the case where one image is displayed using the output images of the plurality of display panels DP, the images are separated as viewed from the user of the display apparatus.

Although it is possible to suppress the display of each display panel DP from being seen separately by reducing the non-display area of each display panel DP (using a display panel DP with a narrow frame), it is difficult to completely eliminate the non-display area of the display panel DP.

Further, when the area of the non-display region of the display panel DP is small, the distance between the end portion of the display panel DP and the element in the display panel DP is short, and thus the element may be easily deteriorated by an impurity entering from the outside of the display panel DP.

In one embodiment of the present invention, the plurality of display panels DP are arranged so that a part thereof overlaps with each other. Of the two display panels DP that overlap, at least the display panel DP located on the display surface side (upper side) has the visible light transmission region 72 adjacent to the pixel portion 71. In one embodiment of the present invention, the pixel portion 71 of the display panel DP disposed on the lower side overlaps the region 72 of the display panel DP disposed on the upper side, through which visible light is transmitted. Therefore, the non-display area between the pixel portions 71 of the two display panels DP that overlap can be reduced, and even eliminated. Thereby, a large display device in which the user hardly sees the joint of the display panel DP can be realized.

At least a part of the non-display region of the display panel DP located on the upper side is the visible light transmission region 72, and may overlap with the pixel portion 71 of the display panel DP located on the lower side. At least a part of the non-display region of the lower display panel DP may overlap the pixel portion 71 of the upper display panel DP or the region 73 blocking visible light. These portions do not affect the reduction of the frame width of the display device (reduction of the area other than the pixel portion), and therefore the reduction of the area may not be performed.

For example, in the case where the organic E L element is used as the display element, the longer the distance between the end of the display panel DP and the organic E L element, the less likely the impurities such as moisture and oxygen will enter (or reach) the organic E L element from the outside of the display panel DP.

In this manner, when a plurality of display panels DP are provided in the display device, it is preferable that the plurality of display panels DP are arranged so that the pixel portions 71 are arranged consecutively between the adjacent display panels DP.

The display panel DP shown in fig. 12A includes a pixel portion 71, a visible light transmission region 72, and a region 73 blocking visible light. The visible light transmission region 72 and the visible light blocking region 73 are both provided adjacent to the pixel portion 71. Fig. 12A illustrates an example in which the display panel DP is provided with the FPC 74.

The pixel section 71 includes a plurality of pixels. The visible light transmission region 72 may be provided with a pair of substrates constituting the display panel DP, a sealant for sealing the display element interposed between the pair of substrates, and the like. In this case, as a member provided in the visible light transmission region 72, a material having transparency to visible light is used. The region 73 blocking visible light may be provided with a wiring or the like electrically connected to the pixels included in the pixel portion 71. In the region 73 that blocks visible light, one or both of a scanning line driver circuit and a signal line driver circuit may be provided. In the region 73 that blocks visible light, terminals connected to the FPC74, wirings connected to the terminals, and the like may be provided.

Fig. 12B and 12C are examples in which the display panels DP shown in fig. 12A are arranged in a matrix of 2 × 2 (two display panels DP are arranged in the vertical direction and the horizontal direction, respectively), fig. 12B is a perspective view of the display surface side of the display panel DP, and fig. 12C is a perspective view of the display panel DP on the side opposite to the display surface.

The four display panels DP (display panels DPa, DPb, DPc, DPd) are arranged so as to include regions overlapping each other. Specifically, the display panels DPa, DPb, DPc, and DPd are arranged such that the visible light transmission region 72 included in one display panel DP includes a region overlapping the pixel portion 71 (display surface side) included in the other display panel DP. The display panels DPa, DPb, DPc, and DPd are arranged so that the region 73 for blocking visible light included in one display panel DP does not overlap the pixel portion 71 of the other display panel DP. In a portion where the four display panels DP are overlapped, the display panel DPb is overlapped on the display panel DPa, the display panel DPc is overlapped on the display panel DPb, and the display panel DPd is overlapped on the display panel DPc.

The short sides of the display panel DPa and the display panel DPb overlap each other, and a part of the pixel portion 71a and a part of the visible light transmission region 72b overlap each other. The long sides of the display panel DPa and the display panel DPc overlap each other, and a part of the pixel portion 71a and a part of the visible light transmission region 72c overlap each other.

A part of the pixel portion 71b overlaps with a part of the visible light transmission region 72c and a part of the visible light transmission region 72 d. In addition, a part of the pixel portion 71c overlaps a part of the visible light transmission region 72 d.

Therefore, a region where the pixel portions 71a to 71d are arranged with almost no seams can be used as the display region 79 of the display device.

Here, the display panel DP preferably has flexibility. For example, a pair of substrates constituting the display panel DP preferably have flexibility.

Thus, for example, as shown in fig. 12B and 12C, the vicinity of the FPC74a of the display panel DPa can be bent, and a part of the display panel DPa and a part of the FPC74a can be arranged below the pixel portion 71B of the display panel DPb adjacent to the FPC74 a. As a result, the FPC74a and the back surface of the display panel DPb can be physically prevented from interfering with each other. Further, when the display panel DPa and the display panel DPb are fixed to overlap with each other, since it is not necessary to consider the thickness of the FPC74a, the difference in height between the top surface of the visible light transmission region 72b and the top surface of the display panel DPa can be reduced. As a result, the end of the display panel DPb located above the pixel portion 71a can be made less visible.

Further, by making each display panel DP flexible, for example, the display panel DPb can be gently curved so that the height of the top surface of the pixel portion 71b of the display panel DPb coincides with the height of the top surface of the pixel portion 71a of the display panel DPa. Accordingly, the heights of the display regions can be made uniform except in the vicinity of the region where the display panel DPa and the display panel DPb overlap, and the display quality of the image displayed in the display region 79 can be improved.

Although the relationship between the display panel DPa and the display panel DPb is described as an example in the above description, the relationship between the other two adjacent display panels DP is the same.

In addition, in order to reduce the step between two adjacent display panels DP, the thickness of the display panel DP is preferably small. For example, the thickness of the display panel DP is preferably 1mm or less, more preferably 300 μm or less, and further preferably 100 μm or less.

[ concrete example 3 of display Panel ]

Fig. 13A and 13B show top views of the display panel 15A. FIG. 13C shows a cross-sectional view along the dotted line C1-C2 of FIG. 13A.

The display panel shown in fig. 13A and 13B includes a pixel portion 71, a visible light transmitting region 72, and a driver circuit 78. The display panel is connected with an FPC 74. Fig. 13A and 13B show an example in which the visible light transmission region 72 is disposed adjacent to the pixel portion 71 along both sides of the pixel portion 71.

The corner of the display panel shown in fig. 13A is angular, while the corner of the display panel shown in fig. 13B is arc-shaped. A display panel using a thin film substrate may have various top plan shapes. For example, when the corners of the display panel have a curvature, cracks are less likely to occur during the division of the display panel, and the display panel may be easily manufactured.

The display panel 15A is a display panel having a top emission structure in a separately applied manner, the display panel 15A includes visible light transmission regions 72 along both sides, a routing wiring of the common electrode 113 cannot be arranged in the visible light transmission regions 72, and therefore, the influence of voltage reduction is more significant, when a voltage is reduced, in the case of manufacturing the display device shown in fig. 12A to 12C using a plurality of display panels 15A, discontinuity of luminance of adjacent display panels is easily perceived as luminance unevenness of the entire display device, however, since the display panel 15A includes an auxiliary wiring, voltage reduction caused by resistance of the common electrode 113 can be suppressed to reduce display unevenness, and further, the common layer included in the E L layer is formed twice, and therefore, even if the display panel 15A includes an auxiliary wiring in the pixel portion 71, the aperture ratio of the pixel is high.

As shown in fig. 13C, the display panel 15A includes a substrate 361, an adhesive layer 363, an insulating layer 365, a transistor 301, a transistor 303, a conductive layer 307, an insulating layer 314, a light-emitting element 20A, a light-emitting element 20B, a light-emitting element 21A, an insulating layer 104, a protective layer 109, an auxiliary wiring 120A, an auxiliary wiring 120B, an adhesive layer 317, a substrate 371, and the like.

The substrate 361 and the substrate 371 are bonded by an adhesive layer 317. Further, the substrate 361 and the insulating layer 365 are bonded with an adhesive layer 363.

In the method for manufacturing the display panel 15A, a transistor, a light-emitting element, or the like formed over a substrate for formation is transferred over the substrate 361.

Each of the light-emitting elements 20A, 20B, and 21A includes pixel electrodes 111A and 111B, an E L layer, and a common electrode 113.

The pixel electrode 111a is electrically connected to the source or drain of the transistor 303. They are connected directly or through other conductive layers.

The pixel electrodes 111B included in the light-emitting elements 20A, 20B, and 21A function as optical adjustment layers. Although fig. 10B and the like show an example in which the pixel electrode 111B covers the pixel electrode 111a, the pixel electrode 111B may not cover the side surface of the pixel electrode 111a as shown in fig. 13C.

The driver circuit 78 includes a transistor 301. The pixel portion 71 includes a transistor 303.

Each transistor includes a back gate, a gate insulating layer 311, a semiconductor layer, a gate insulating layer, a gate, an insulating layer 315, a source, and a drain. The semiconductor layer includes a channel formation region and a pair of low-resistance regions. The back gate (lower gate in fig. 13C) overlaps with the channel formation region with the gate insulating layer 311 interposed therebetween. The gate electrode (the upper gate electrode in fig. 13C) overlaps with the channel formation region with the gate insulating layer interposed therebetween. The source and drain electrodes are electrically connected to the low-resistance region through an opening formed in the insulating layer 315.

The pixel portion 71, the driver circuit 78, and the connection portion 306 of the display panel 15A shown in fig. 13C are similar in configuration to the display panel 10A (fig. 10B) in most parts, and therefore, the above description can be referred to.

The layers included in the visible light transmission region 72 transmit visible light. Fig. 13C shows an example in which the visible light transmission region 72 includes a substrate 361, an adhesive layer 363, an insulating layer 365, a gate insulating layer 311, an insulating layer 315, a protective layer 109, an adhesive layer 317, and a substrate 371. In this laminated structure, it is preferable that the materials of the respective layers are selected so that the difference in refractive index between the interfaces is small. By reducing the refractive index of the two layers in contact with each other, the seam of the two display panels is not readily visible to the user.

The number of insulating layers in the visible light transmission region 72 is preferably smaller than the number of insulating layers in the portion of the pixel portion 71 near the visible light transmission region 72. By reducing the number of insulating layers included in the visible light transmission region 72, the interface having a large difference in refractive index can be reduced. This can suppress reflection of external light in the visible light transmission region 72. Further, the transmittance of visible light in the visible light transmission region 72 can be increased, and the difference in luminance (brightness) between the portion of the display panel disposed on the lower side where the display is viewed through the visible light transmission region 72 and the portion of the display panel not viewed through the visible light transmission region can be reduced. Therefore, display unevenness or luminance unevenness of the display device can be suppressed.

Fig. 14 shows an example of a cross-sectional view of a display device in which two display panels 15A shown in fig. 13C are overlapped.

In the display device shown in fig. 14, the display panel located on the display surface side (upper side) includes a visible light transmission region 72 adjacent to the pixel portion 71. The pixel portion 71 of the lower display panel overlaps the visible light transmission region 72 of the upper display panel. The region of the lower display panel that blocks visible light (the driver circuit 78, the connection portion 306, and the like) overlaps the pixel portion 71 of the upper display panel. Therefore, the non-display area between the pixel portions of the two display panels that overlap can be reduced, and even eliminated. Thus, a large display device in which the seams of the display panel are not easily visible to the user can be realized.

The display device shown in fig. 14 includes a light-transmitting layer 102 which has a refractive index higher than that of air and transmits visible light between the pixel portion 71 of the lower display panel and the visible light-transmitting region 72 of the upper display panel. Accordingly, air can be suppressed from entering between the two display panels, and reflection at the interface due to the difference in refractive index can be reduced. Also, display unevenness or luminance unevenness of the display device can be suppressed.

Next, the structure of the common layer in the region N shown in fig. 13A is explained using fig. 15A to 15C. Here, a case where the common layer 161a and the common layer 161b are formed using one mask 155 will be described.

As shown in fig. 15A, after the common layer 161a is formed using the mask 155, the common layer 161b may also be formed using the mask 155 by moving the mask 155 in the X direction or the Y direction by a distance equivalent to one pixel. Fig. 15B shows a case where the common layer 161B is formed by moving the mask 155 by a distance equivalent to one pixel in the X direction. Here, as shown in fig. 15B, the common layer 161B is also formed in every other pixel in the Y direction in the visible light transmission region 72. Fig. 15C shows a top view of the common layer 161a and the common layer 161 b. At this time, as shown in fig. 15D, it is preferable that the common electrode 113 covers the common layer 161b formed in the visible light transmission region 72, and an end portion of the common electrode 113 is provided so as to be positioned outside an end portion of the common layer 161 b. In particular, the end of the common electrode 113 is preferably in contact with the inorganic film. This can suppress impurities from entering the common layer 161b in the visible light transmission region 72.

The above-described structure can be applied not only to the region N shown in fig. 13A but also to the region N shown in fig. 10A. That is, when the common layer 161a and the common layer 161b are formed using one mask, the common layer 161a or the common layer 161b is disposed at substantially equal pitches outside the pixel section 71 of the display panel. This is also a feature obtained by forming the common layer 161 in multiple times, which is a feature of one embodiment of the present invention.

Fig. 16A and 16B show a modification example of the display panel. The display panel shown in fig. 16A and 16B is formed by transferring the protective layer 375 and the light-shielding layer BM formed over the formation substrate to the substrate 371. The substrate 371 and the protective layer 375 are attached by an adhesive layer 373. In this manner, the protective layer 109 over the light-emitting element can be omitted and the protective layer can be provided on the counter substrate side.

In fig. 16A, a source or a drain of the transistor 303 and the pixel electrode 111a of the light-emitting element are electrically connected through the conductive layer 128 a. In this manner, a layer of a conductive layer can be provided between the light-emitting element and the transistor. Specifically, the conductive layer 128a is provided over the insulating layer 314a covering the transistor 303, the insulating layer 314b is provided over the conductive layer 128a, and the pixel electrode 111a is provided over the insulating layer 314 b. The pixel electrode 111a is connected to the conductive layer 128a through an opening in the insulating layer 314b, and the conductive layer 128a is connected to the source or the drain of the transistor 303 through an opening in the insulating layer 314 a. Further, a conductive layer 128b is provided over the insulating layer 314 a. The conductive layer 128b can be formed using the same material as the conductive layer 128a in the same process as the conductive layer 128 a. The conductive layer 128b can be used as an auxiliary wiring of the common electrode 113 because it is electrically connected to the common electrode 113. In the connection portion 122, the common electrode 113 is connected to the auxiliary wiring 120b through the opening of the insulating layer 104. The auxiliary wiring 120b is in contact with the auxiliary wiring 120 a. The auxiliary wiring 120a is connected to the conductive layer 128b through an opening of the insulating layer 314 b. As such, the common electrode 113 may be electrically connected to a conductive layer in the same layer as the pixel electrode and conductive layers in other layers. Further, the common electrode 113 and the conductive layer 128b may be directly connected without providing the auxiliary wirings 120a and 120 b.

Fig. 16B shows an example in which the layer of the auxiliary wiring 120 is different from the layers of the transistor, the wiring, and the light-emitting element. By providing a layer including only the auxiliary wiring 120, the auxiliary wiring 120 can be provided in a large area. This can more effectively suppress a voltage drop due to the resistance of the common electrode 113. In fig. 16B, the conductive layer 128 is provided over the insulating layer 314a, the insulating layer 314B is provided over the conductive layer 128, the auxiliary wiring 120 is provided over the insulating layer 314B, and the insulating layer 314c is provided over the auxiliary wiring 120. The common electrode 113 is electrically connected to the auxiliary wiring 120 through the opening formed in the insulating layer 104 and the insulating layer 314 c. The transistor is electrically connected through the opening conductive layer 128 formed in the insulating layer 314 a. The pixel electrode is electrically connected to the conductive layer 128 through openings formed in the insulating layer 314b and the insulating layer 314 c.

[ concrete example 4 of display Panel ]

Fig. 17A shows a top view of the display panel 15B. Fig. 17B shows a sectional view along the chain line C3-C4 in fig. 17A.

The display panel 15B shown in fig. 17A includes a pixel portion 71, a visible light transmission region 72, and a driver circuit 78. The display panel 15B is connected with an FPC 74. The display panel 15A (fig. 13A) has a structure in which an FPC74 is connected to the display surface side, and the display panel 15B has a structure in which an FPC74 is connected to the side opposite to the display surface (the back surface side). Fig. 17A shows an example in which the visible light transmission region 72 is adjacent to the pixel portion 71 and is arranged along both sides of the pixel portion 71.

The main difference between the display panel 15A and the display panel 15B is the structure of the connection portion 306.

In the connection portion 306 of the display panel 15B, the conductive layer 309 and the FPC74 are electrically connected through the connection body 319. Conductive layer 309 is electrically connected to conductive layer 308 through an opening in insulating layer 365.

Next, a method for manufacturing the display panel 15B will be described focusing on the connection portion 306 with reference to fig. 18A, 18B1, 18B2, 18C1, and 18C 2.

First, a peeling layer 353 is formed over a formation substrate 351, and a layer to be peeled is formed over the peeling layer 353 (fig. 18A). As a layer to be peeled, first, a conductive layer 309 is formed over the peeling layer 353, an insulating layer 365 is formed over the peeling layer 353 and the conductive layer 309, and an opening which overlaps with the conductive layer 309 is formed in the insulating layer 365. Further, a conductive layer 308 connected to the conductive layer 309 through an opening is formed. The conductive layer 308 can be formed using the same material as the gate of the transistor in the same process as the gate of the transistor. Note that the conductive layer 308 can be formed using the same material as the source and the drain of the transistor in the same step as the source and the drain of the transistor. Then, the gate insulating layer 311 is sequentially formed to the substrate 371.

Next, the formation substrate 351 is peeled off. Fig. 18B1 shows an example in which peeling occurs at the interface between the peeling layer 353 and the conductive layer 309 and the insulating layer 365. This can expose the conductive layer 309. As shown in fig. 18C1, the conductive layer 309 and an FPC74 can be electrically connected to each other using a connecting body 319.

Further, as shown in fig. 18B2, peeling may occur in the peeling layer 353. At this time, the peeling layer 353a remains on the formation substrate 351 side, and the peeling layer 353b remains in contact with the conductive layer 309. When the conductive layer 309 is not exposed after the formation substrate 351 is peeled off, a part of the peeling layer 353b is preferably removed to expose the conductive layer 309. Then, as shown in fig. 18C2, the conductive layer 309 and an FPC74 can be electrically connected using the connector 319.

The formation substrate 351 has rigidity enough to be easily transported, and has heat resistance against the temperature in the manufacturing process. Examples of a material that can be used for the substrate 351 include glass, quartz, ceramics, sapphire, resin, a semiconductor, a metal, an alloy, and the like. Examples of the glass include alkali-free glass, barium borosilicate glass, and aluminoborosilicate glass.

The peeling layer 353 may be formed using an organic material or an inorganic material.

Examples of the organic material that can be used for the release layer 353 include polyimide resin, acrylic resin, epoxy resin, polyamide resin, polyimide amide resin, siloxane resin, benzocyclobutene resin, phenol resin, and the like.

Examples of the inorganic material that can be used for the separation layer 353 include a metal containing an element selected from tungsten, molybdenum, titanium, tantalum, niobium, nickel, cobalt, zirconium, zinc, ruthenium, rhodium, palladium, osmium, iridium, and silicon, an alloy containing the element, a compound containing the element, and the like. The crystalline structure of the layer containing silicon may be any of amorphous, microcrystalline, or polycrystalline.

The formation substrate 351 can be peeled by irradiating laser light to the peeling interface. As the laser, an excimer laser, a solid laser, or the like can be used. For example, a semiconductor pumped solid state laser (DPSS) may also be used. Alternatively, the formation substrate 351 may be peeled off by applying a pull-up force in the vertical direction.

An FPC74 is connected to the display panel 15B on the side opposite to the display surface (back surface side). For example, by using the display panel 15B, the multi-screen display of fig. 32 to be described in embodiment 2 can be manufactured.

[ example of Structure of transistor ]

Next, a transistor which can be used for a display panel or a display device will be described.

The transistor structure included in the display panel or the display device is not particularly limited. For example, a planar transistor, a staggered transistor, or an inverted staggered transistor may be used. In addition, the transistors may have a top gate structure or a bottom gate structure. Alternatively, gate electrodes may be provided above and below the channel.

Fig. 19A and 19B show a structure example of a transistor. Each transistor is provided between the insulating layer 141 and the insulating layer 208. The insulating layer 141 is preferably used as a base film. The insulating layer 208 is preferably used as a planarization film.

The transistors 220 shown in fig. 19A are all transistors of a bottom-gate structure including metal oxide in the semiconductor layer 204. A metal oxide may be used as the oxide semiconductor.

As a semiconductor of the transistor, an oxide semiconductor is preferably used. It is preferable to use a semiconductor material having a wider band gap and a lower carrier density than silicon because off-state current (off-state current) of the transistor can be reduced.

The transistor 220 includes a conductive layer 201, an insulating layer 202, a conductive layer 203a, a conductive layer 203b, and a semiconductor layer 204. The conductive layer 201 is used as a gate. The insulating layer 202 is used as a gate insulating layer. The semiconductor layer 204 overlaps with the conductive layer 201 with the insulating layer 202 interposed therebetween. The conductive layer 203a and the conductive layer 203b are electrically connected to the semiconductor layer 204. Transistor 220 is preferably covered by insulating layer 211 and insulating layer 212. Various inorganic insulating films can be used for the insulating layer 211 and the insulating layer 212. In particular, an oxide insulating film is preferably used for the insulating layer 211, and a nitride insulating film is preferably used for the insulating layer 212.

The transistor 230 shown in fig. 19B is a transistor of a bottom-gate structure including polycrystalline silicon in a semiconductor layer.

The transistor 230 includes a conductive layer 201, an insulating layer 202, a conductive layer 203a, a conductive layer 203B, a semiconductor layer, and an insulating layer 213, the conductive layer 201 is used as a gate, the insulating layer 202 is used as a gate insulating layer, the semiconductor layer includes a channel formation region 214a and a pair of low-resistance regions 214B, the semiconductor layer may also include an L DD (L ighty do drain) region, fig. 19B illustrates an example in which a L DD region 214c is included between the channel formation region 214a and the low-resistance regions 214B, the channel formation region 214a overlaps the conductive layer 201 with the insulating layer 202 interposed therebetween, the conductive layer 203a is electrically connected to one of the pair of low-resistance regions 214B through openings provided in the insulating layer 202 and the insulating layer 213, and similarly, the conductive layer 203B is electrically connected to the other of the pair of low-resistance regions 214B.

[ Metal oxide ]

A metal oxide used as an oxide semiconductor is preferably used for the semiconductor layer. Hereinafter, a metal oxide which can be used for the semiconductor layer will be described.

The metal oxide preferably contains at least indium or zinc. Particularly preferably indium and zinc. In addition, aluminum, gallium, yttrium, tin, or the like is preferably contained. Alternatively, one or more of boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, or the like may be contained.

Here, a case where the metal oxide is an In-M-Zn oxide containing indium, an element M, and zinc is considered. Note that the element M is aluminum, gallium, yttrium, tin, or the like. As other elements which can be used as the element M, there are boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium and the like. Note that as the element M, a plurality of the above elements may be combined.

In this specification and the like, a metal oxide containing nitrogen is also sometimes referred to as a metal oxide (metal oxide). In addition, a metal oxide containing nitrogen may also be referred to as a metal oxynitride (metal oxynitride). For example, a metal oxide containing nitrogen such as zinc oxynitride (ZnON) can be used for the semiconductor layer.

Oxide semiconductors (metal oxides) are classified into single crystal oxide semiconductors and non-single crystal oxide semiconductors. Examples of the non-single crystal oxide semiconductor include a CAAC-OS (c-oxide aligned crystalline oxide semiconductor), a polycrystalline oxide semiconductor, an nc-OS (nanocrystalline oxide semiconductor), an a-likeOS (amorphous oxide semiconductor), and an amorphous oxide semiconductor.

CAAC-OS has c-axis orientation, and a plurality of nanocrystals are connected in the a-b plane direction, and the crystal structure is distorted. Note that the distortion is a portion in which the direction of lattice alignment changes between a region in which lattice alignments coincide and a region in which other lattice alignments coincide among regions in which a plurality of nanocrystals are connected.

Although the nanocrystals are substantially hexagonal, they are not limited to regular hexagonal shapes, and there are cases where they are not regular hexagonal shapes. In addition, the distortion may have a lattice arrangement such as a pentagonal or heptagonal shape. In the CAAC-OS, no clear grain boundary (grain boundary) is observed even in the vicinity of the distortion. That is, it is found that the formation of grain boundaries can be suppressed due to the distortion of the lattice arrangement. This is because CAAC-OS can contain distortion due to low density of oxygen atom arrangement in the a-b plane direction, or due to change in bonding distance between atoms caused by substitution of metal elements.

CAAC-OS tends to have a layered crystal structure (also referred to as a layered structure) In which a layer containing indium and oxygen (hereinafter referred to as an In layer) and a layer containing the elements M, zinc, and oxygen (hereinafter referred to as an (M, Zn) layer) are stacked. In addition, indium and the element M may be substituted for each other, and In the case where the element M In the (M, Zn) layer is substituted with indium, the layer may also be displayed as an (In, M, Zn) layer. In addition, In the case where indium In the In layer is substituted with the element M, the layer may be shown as an (In, M) layer.

CAAC-OS is a metal oxide with high crystallinity. On the other hand, in CAAC-OS, it is not easy to observe a clear grain boundary, and therefore, a decrease in electron mobility due to the grain boundary does not easily occur. In addition, the crystallinity of the metal oxide may be lowered by the entry of impurities, the generation of defects, or the like, and thus the CAAC-OS may be said to be impurities or defects (oxygen vacancies (also referred to as V)_O(oxygen vaccy)), etc.). Therefore, the metal oxide including CAAC-OS is stable in physical properties. Therefore, the metal oxide including the CAAC-OS has high heat resistance and high reliability.

In nc-OS, the atomic arrangement in a minute region (for example, a region of 1nm to 10nm, particularly 1nm to 3 nm) has periodicity. In addition, no regularity in crystallographic orientation was observed between different nanocrystals for nc-OS. Therefore, orientation was not observed in the entire film. Therefore, sometimes nc-OS is not different from a-likeOS or an amorphous oxide semiconductor in some analysis methods.

In addition, indium-gallium-zinc oxide (hereinafter, IGZO), which is one of metal oxides including indium, gallium, and zinc, may have a stable structure when composed of the above-described nanocrystal. In particular, IGZO tends to be less likely to undergo crystal growth in the atmosphere, and therefore, it is sometimes structurally stable when IGZO is formed of small crystals (for example, the nanocrystals described above) as compared with when IGZO is formed of large crystals (here, crystals of several mm or crystals of several cm).

The a-likeOS is a metal oxide having a structure between nc-OS and an amorphous oxide semiconductor. The a-likeOS contains holes or low density regions. That is, the crystallinity of a-likeOS is lower than that of nc-OS and CAAC-OS.

Oxide semiconductors (metal oxides) have various structures and various characteristics. The oxide semiconductor according to one embodiment of the present invention may include two or more of an amorphous oxide semiconductor, a polycrystalline oxide semiconductor, a-likeOS, nc-OS, and CAAC-OS.

The metal oxide film used as the semiconductor layer may be formed using either or both of an inert gas and an oxygen gas. Note that the oxygen flow rate ratio (oxygen partial pressure) when forming the metal oxide film is not particularly limited. However, in the case of obtaining a transistor with high field-effect mobility, the oxygen flow rate ratio (oxygen partial pressure) in forming the metal oxide film is preferably 0% or more and 30% or less, more preferably 5% or more and 30% or less, and further preferably 7% or more and 15% or less.

The energy gap of the metal oxide is preferably 2eV or more, more preferably 2.5eV or more, and further preferably 3eV or more. Thus, by using a metal oxide having a wide energy gap, the off-state current of the transistor can be reduced.

The metal oxide film may be formed by a sputtering method, or a P L D method, a PECVD method, a thermal CVD method, an a L D method, a vacuum deposition method, or the like.

As described above, the display panel of this embodiment mode includes the auxiliary wiring connected to the common electrode of the light emitting element, and the aperture ratio of the pixel is high. This can suppress the luminance unevenness of the display panel and improve the display quality of the display panel. Further, a display panel which has high reliability and can perform high-luminance display can be realized.

This embodiment mode can be combined with any of the other embodiment modes and embodiments as appropriate. In the present specification, when a plurality of configuration examples are shown in one embodiment, the configuration examples may be appropriately combined.

(embodiment mode 2)

In this embodiment, a display panel according to an embodiment of the present invention will be described with reference to fig. 20A, 20B, 21A, and 21B.

Fig. 20A shows a block diagram of a pixel the pixel of this embodiment includes a Memory (Memory) in addition to a switching transistor (switching tr), a driving transistor (DrivingTr), and a light emitting element (O L ED).

The memory is supplied with DATA _ W. When the pixels are supplied with DATA _ W in addition to the display DATA, the current flowing through the light emitting elements increases, and thus the display panel can exhibit high luminance.

When the potential of the DATA DATA _ W is represented as V_wThe potential of the display DATA DATA is represented as V_dataThe capacitance of the memory is denoted as C_wWhen, the gate voltage V of the driving transistor can be expressed by formula (1)_g。

[ equation 1]

When V is_w＝V_dataWhen is taken as V_gApplication of more than V_dataA larger current can flow. That is, the current flowing through the light emitting element becomes large and the luminance becomes high.

Fig. 20B shows a specific circuit diagram of the pixel.

The pixel shown in fig. 20B includes a transistor M1, a transistor M2, a transistor M3, a transistor M4, a transistor M5, a capacitor Cs, a capacitor Cw, and a light-emitting element 124.

One of a source and a drain of the transistor M1 is electrically connected to one electrode of the capacitor Cw. The other electrode of the capacitor Cw is electrically connected to one of the source and the drain of the transistor M4. One of a source and a drain of the transistor M4 is electrically connected to the gate of the transistor M2. The gate of the transistor M2 is electrically connected to one electrode of the capacitor Cs. The other electrode of the capacitor Cs is electrically connected to one of the source and the drain of the transistor M2. One of a source and a drain of the transistor M2 is electrically connected to one of a source and a drain of the transistor M5. One of a source and a drain of the transistor M5 is electrically connected to one of a source and a drain of the transistor M3. The other of the source and the drain of the transistor M5 is electrically connected to one electrode of the light-emitting element 124. Each transistor shown in fig. 20B includes a back gate electrically connected to the gate, but the connection manner of the back gate is not limited thereto. In addition, a back gate may not be provided in the transistor.

Here, a node to which the other electrode of the capacitor Cw, one of the source and the drain of the transistor M4, the gate of the transistor M2, and one electrode of the capacitor Cs are connected is referred to as a node NM. Note that a node to which the other of the source and the drain of the transistor M5 and one electrode of the light-emitting element 124 are connected is referred to as a node NA.

The gate of the transistor M1 is electrically connected to the wiring G1. The gate of the transistor M3 is electrically connected to the wiring G1. The gate of the transistor M4 is electrically connected to the wiring G2. The gate of the transistor M5 is electrically connected to the wiring G3. The other of the source and the drain of the transistor M1 is electrically connected to the wiring DATA. The other of the source and the drain of the transistor M3 is electrically connected to the wiring V0. The other of the source and the drain of the transistor M4 is electrically connected to the wiring DATA _ W.

The other of the source and the drain of the transistor M2 is electrically connected to the power supply line 127 (high potential). The other electrode of the light-emitting element 124 is electrically connected to a common wiring 129. Note that an arbitrary potential can be supplied to the common wiring 129.

The wirings G1, G2, and G3 can be used as signal lines for controlling the operation of the transistors. The wiring DATA may be used as a signal line for supplying an image signal to the pixel. Further, the wiring DATA _ W may be used as a signal line for writing DATA to the memory circuit MEM. The wiring DATA _ W may be used as a signal line for supplying a correction signal to the pixel. The wiring V0 is used as a monitor line for obtaining electrical characteristics of the transistor M4. Writing of an image signal can be stabilized by supplying a specific potential from the wiring V0 to one electrode of the capacitor Cs through the transistor M3.

The transistor M2, the transistor M4, and the capacitor Cw form a memory circuit MEM. The node NM is a storage node, and by turning on the transistor M4, a signal supplied to the wiring DATA _ W can be written to the node NM. By using a transistor with a very small off-state current as the transistor M4, the potential of the node NM can be held for a long time.

As the transistor M4, for example, a transistor using a metal oxide for a channel formation region (hereinafter, referred to as an OS transistor) can be used. This makes it possible to minimize the off-state current of the transistor M4 and to maintain the potential of the node NM for a long time. In this case, an OS transistor is preferably used as another transistor constituting the pixel. As a specific example of the metal oxide, the contents of embodiment 1 can be referred to.

The OS transistor has a large energy gap and exhibits a characteristic of extremely small off-state current. Unlike a transistor including Si in a channel formation region (hereinafter, referred to as an Si transistor), an OS transistor does not cause impact ionization, avalanche breakdown, a short channel effect, or the like, and thus a highly reliable circuit can be formed.

Further, a Si transistor may be used as the transistor M4. In this case, a Si transistor is preferably used as another transistor constituting a pixel.

Examples of the Si transistor include a transistor containing amorphous silicon, a transistor containing crystalline silicon (typically, low-temperature polysilicon), a transistor containing single crystal silicon, and the like.

One pixel may also include an OS transistor and a Si transistor.

In the pixel, a signal written to the node NM is capacitively coupled with an image signal supplied from the wiring DATA and output to the node NA. The transistor M1 may have a function of selecting a pixel. The transistor M5 may have a function as a switch for controlling light emission of the light emitting element 124.

For example, when the signal written from the wiring DATA _ W to the node NM is larger than the threshold voltage (V2) of the transistor M2_th) Then, the transistor M2 is turned on before the image signal is written, and the light-emitting element 124 emits light. Therefore, it is preferable to provide the transistor M5 and toAfter the potential of the node NM is fixed, the transistor M5 is turned on, and the light-emitting element 124 emits light.

That is, the correction signal may be added to the supplied image signal as long as the desired correction signal is stored to the node NM. Note that, since the correction signal may be attenuated due to factors on the transmission path, it is preferable to generate the correction signal in consideration of the attenuation.

The operation of the pixel shown in fig. 20B will be described in detail with reference to the timing charts shown in fig. 21A and 21B, a positive signal or a negative signal may be used as the correction signal (Vp) supplied to the wiring DATA _ W, and a case where a positive signal is supplied will be described here.

First, an operation of writing the correction signal (Vp) to the node NM is described with reference to fig. 21A. This operation may be performed every frame, and at least one writing operation may be performed before the image signal is supplied. Further, the refresh operation is appropriately performed to rewrite the correction signal to the node NM.

At time T1, when the potential of the wiring G1 is set to "H", the potential of the wiring G2 is set to "L", the potential of the wiring G3 is set to "L", and the potential of the wiring DATA is set to "L", the transistor M1 is turned on, and the potential of the other electrode of the capacitor Cw is set to "L".

This operation is a reset operation performed before capacitive coupling. Before time T1, light emitting element 124 emits light in the previous frame. However, since the potential of the reset operation node NM changes and the current flowing through the light-emitting element 124 changes, it is preferable that the transistor M5 be turned off to stop the light-emitting element 124 from emitting light.

At time T2, when the potential of the wiring G1 is "H", the potential of the wiring G2 is "H", the potential of the wiring G3 is "L", and the potential of the wiring DATA is "L", the transistor M4 is turned on, and the potential of the wiring DATA _ W (correction signal (Vp)) is written into the node NM.

At time T3, when the potential of the wiring G1 is "H", the potential of the wiring G2 is "H", the potential of the wiring G3 is "L", and the potential of the wiring DATA is "L", the transistor M4 is turned off, and the correction signal (Vp) is held at the node NM.

At time T4, when the potential of the wiring G1 is "L", the potential of the wiring G2 is "L", the potential of the wiring G3 is "L", and the potential of the wiring DATA is "L", the transistor M1 is turned off, and the writing operation of the correction signal (Vp) is completed.

Next, an operation of correcting the image signal (Vs) and an operation of causing the light emitting element 124 to emit light will be described with reference to fig. 21B.

At time T11, when the potential of the wiring G1 is "H", the potential of the wiring G2 is "L", the potential of the wiring G3 is "L", and the potential of the wiring DATA _ W is "L", the transistor M1 is turned on, and the potential of the wiring DATA is added to the potential of the node NM by the capacitive coupling of the capacitor Cw.

At time T12, when the potential of the wiring G1 is "L", the potential of the wiring G2 is "L", the potential of the wiring G3 is "L", and the potential of the wiring DATA _ W is "L", the transistor M1 is turned off, and the potential of the node NM is fixed to Vs + Vp.

At time T13, when the potential of the wiring G1 is "L", the potential of the wiring G2 is "L", the potential of the wiring G3 is "H", and the potential of the wiring DATA _ W is "L", the transistor M5 is turned on, the potential of the node NA is Vs + Vp, and the light-emitting element 124 emits light, strictly speaking, the potential of the node NA corresponds to a value obtained by subtracting the threshold voltage (V + Vp) of the transistor M2 from Vs + Vp_th) Here, V_thIs a negligible minimum.

The above is the operation of correcting the image signal (Vs) and the operation of causing the light emitting element 124 to emit light. Note that, although the writing operation of the correction signal (Vp) and the input operation of the image signal (Vs) described above may be performed continuously, it is preferable that the writing operation of the correction signal (Vp) is performed on all pixels before the input operation of the image signal (Vs) is performed. In one embodiment of the present invention, since the same image signal can be supplied to a plurality of pixels at the same time, the operation speed is increased by writing the correction signal (Vp) to all the pixels first, and details will be described later.

As described above, by causing the light emitting element to emit light using the image signal and the correction signal, the current flowing through the light emitting element can be increased, and thus high luminance can be expressed. Since a voltage equal to or higher than the output voltage of the source driver can be applied as the gate voltage of the driving transistor, power consumption of the source driver can be reduced.

This embodiment mode can be combined with any of the other embodiment modes and embodiments as appropriate.

(embodiment mode 3)

In this embodiment, an electronic device according to an embodiment of the present invention will be described with reference to fig. 22A to 22D.

The electronic device of the present embodiment includes the display device of one embodiment of the present invention in a display portion. In the display device according to the embodiment of the present invention, the area of the display region can be increased without limitation by increasing the number of display panels. Therefore, the Display device of one embodiment of the present invention may be adapted to a digital signage or a PID (public information Display) or the like.

The display portion of the electronic device of the present embodiment can display, for example, a video image having a resolution of 4K2K, 8K4K, 16K8K or higher with full high definition. The screen size of the display portion may be 20 inches or more, 30 inches or more, 50 inches or more, 60 inches or more, or 70 inches or more in diagonal.

Examples of electronic devices include electronic devices having a large screen such as a television set, a desktop or notebook personal computer, a display for a computer or the like, a large-sized game machine such as a digital signage or a pachinko machine, and a digital camera, a digital video camera, a digital photo frame, a mobile phone, a portable game machine, a portable information terminal, and an audio reproducing device.

The electronic device of the present embodiment can be assembled along a curved surface of an inner wall or an outer wall of a house or a tall building, an interior trim or an exterior trim of an automobile.

The electronic device of this embodiment may also include an antenna. By receiving the signal through the antenna, an image, data, or the like can be displayed on the display unit. In addition, when the electronic device includes an antenna and a secondary battery, the antenna can be used for non-contact power transmission.

The electronic device of the present embodiment may include a sensor (the sensor has a function of measuring a force, a displacement, a position, a velocity, an acceleration, an angular velocity, a rotational speed, a distance, light, liquid, magnetism, temperature, a chemical substance, sound, time, hardness, an electric field, current, voltage, electric power, radiation, a flow rate, humidity, inclination, vibration, odor, or infrared rays).

The electronic device of this embodiment mode can have various functions. For example, the following functions may be provided: a function of displaying various information (still image, moving image, character image, and the like) on the display unit; a function of a touch panel; a function of displaying a calendar, date, time, or the like; functions of executing various software (programs); a function of performing wireless communication; a function of reading out a program or data stored in a storage medium; and the like.

Fig. 22A shows an example of a television device. In the television set 7100, a display portion 7000 is incorporated in a housing 7101. Here, a structure in which the housing 7101 is supported by a bracket 7103 is shown.

The display device according to one embodiment of the present invention can be applied to the display portion 7000.

The television device 7100 shown in fig. 22A can be operated by using an operation switch provided in the housing 7101 or a remote controller 7111 provided separately. Further, a touch sensor may be provided in display portion 7000, or operation of television set 7100 may be performed by touching display portion 7000 with fingers or the like. The remote controller 7111 may be provided with a display unit for displaying data output from the remote controller 7111. By using the operation keys or the touch panel provided in the remote controller 7111, the channel and the volume can be operated, and the video displayed on the display portion 7000 can be operated.

The television device 7100 includes a receiver, a modem, and the like. General television broadcasting can be received by using a receiver. Further, the television device is connected to a communication network of a wired or wireless system via a modem, and information communication is performed in one direction (from a sender to a receiver) or in two directions (between a sender and a receiver or between receivers).

Fig. 22B shows an example of a notebook personal computer. The notebook personal computer 7200 includes a housing 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, and the like. A display portion 7000 is incorporated in the housing 7211.

The display device according to one embodiment of the present invention can be applied to the display portion 7000.

Fig. 22C and 22D show examples of the digital signage.

Digital signage 7300 shown in fig. 22C includes a housing 7301, a display portion 7000, a speaker 7303, and the like, and may further include L ED lamps, operation keys (including a power switch and an operation switch), connection terminals, various sensors, a microphone, and the like.

Fig. 22D shows the digital signage 7400 disposed on a cylindrical post 7401. The digital signage 7400 includes a display 7000 provided along the curved surface of the pillar 7401.

In fig. 22C and 22D, the display device according to one embodiment of the present invention can be applied to the display portion 7000.

The larger the display 7000 is, the larger the amount of information that can be provided at a time. The larger the display 7000 is, the more attractive the attention is, and for example, the advertisement effect can be improved.

The use of a touch panel for the display portion 7000 is preferable because not only a still image or a moving image can be displayed on the display portion 7000 but also a user can intuitively perform an operation. Further, when the device is used for providing information such as route information and traffic information, usability can be improved by intuitive operation.

As shown in fig. 22C and 22D, digital signage 7300 or digital signage 7400 can be linked with information terminal device 7311 such as a smartphone or information terminal device 7411 carried by a user, preferably by wireless communication. For example, the advertisement information displayed on display portion 7000 may be displayed on the screen of information terminal device 7311 or information terminal device 7411. Further, by operating information terminal device 7311 or information terminal device 7411, the display of display unit 7000 can be switched.

Further, a game can be executed on digital signage 7300 or digital signage 7400 with the screen of information terminal device 7311 or information terminal device 7411 as an operation unit (controller). Thus, a plurality of users can participate in the game at the same time, and enjoy the game.

This embodiment mode can be combined with other embodiment modes as appropriate.

[ example 1]

In this example, the results of actually manufacturing a display panel after studying the structure of the auxiliary wiring will be described.

[ example 1 of auxiliary Wiring ]

First, the pixel 130a shown in fig. 1A and the connection portion 122 shown in fig. 1B described in specific example 1 of the display panel will be examined. Then, the display panel was actually manufactured based on the study results, and the interface of the connection portion 122 of the display panel was observed.

First, the connection portion 122 was studied. As a result, when the pixel size was 225 μm □ (13 inches, high definition (hd)), and the distance between the open end of the metal mask and the open end of the pixel and the distance between the open end of the metal mask and the central portion of the connection portion 122 were 20 μm, the aperture ratio of the pixel 130a was estimated to be 41.1%. The aperture ratio when the common layer was formed once was estimated to be about 30%, and it was found that the aperture ratio was significantly improved by forming the common layer twice.

Next, fig. 23 shows a Scanning Transmission Electron Microscope (STEM) image of the connection portion 122 of the display panel actually manufactured. As shown in fig. 23, in the connection part 122, the common electrode 113 may be connected to the auxiliary wiring 120.

[ example 2 of auxiliary Wiring ]

Further, the following methods were studied: even if a common layer shared by sub-pixels of a plurality of colors is formed over the entire display region of the display panel, the auxiliary wiring and the common electrode can be electrically connected. Then, the display panel was actually manufactured, and whether or not the auxiliary wiring and the common electrode were electrically connected was confirmed. A specific method will be described with reference to fig. 24A to 24F.

First, as shown in fig. 24A, the reflective electrode 125a and the transparent electrode 125b are sequentially formed on the insulating layer 101. Next, as shown in fig. 24B, only the transparent electrode 125B is processed to form the pixel electrode 111B and the auxiliary wiring 120B. Then, as shown in fig. 24C, the reflective electrode 125a is processed to form the pixel electrode 111a and the auxiliary wiring 120 a. At this time, the etching time is adjusted so that the end of the auxiliary wiring 120a is positioned inside the end of the auxiliary wiring 120b, thereby forming an eave-shaped auxiliary wiring. In the processing, wet etching which can perform isotropic etching is used. Fig. 25A shows a STEM image of actually manufactured eave-shaped auxiliary wirings. As can be seen from fig. 25A, the eave-shaped auxiliary wiring in which the end portion of the auxiliary wiring 120a is located inside the end portion of the auxiliary wiring 120b is formed.

Next, the insulating layer 104 was formed (fig. 24D), the insulating layer 104 was formed so as to cover the end portions of the pixel electrode 111a and the pixel electrode 111b and not to cover the end portions of the auxiliary wiring 120a and the auxiliary wiring 120b, the E L layer 112 was formed so as to be cut off by the eave-shaped auxiliary wiring as shown in fig. 24E, the common electrode 113 was formed so as to be connected to the side surface of the auxiliary wiring 120b as shown in fig. 24E, and resistance measurement was performed after the E L layer 112 and the common electrode 113 were actually formed, and as a result, it was confirmed that the auxiliary wiring and the common electrode 113 were electrically connected.

Fig. 25B shows a STEM image of an eave-shaped auxiliary wiring that is actually manufactured, note that the sample shown in fig. 25B is a sample different from that of fig. 25A, in fig. 25B, the auxiliary wiring 120a and the auxiliary wiring 120B are collectively referred to as the auxiliary wiring 120, and as shown in fig. 25B, it is confirmed that the E L layer 112 is cut and the auxiliary wiring 120 and the common electrode 113 are connected to each other.

[ example 3 of auxiliary Wiring ]

In addition, a structure in which an auxiliary wiring is provided on the counter substrate side was studied, and a cross section of a connection portion between the auxiliary wiring and the common electrode was observed while actually manufacturing a display panel. A specific method will be described with reference to fig. 26A and 26B.

As shown in fig. 26A, the spacer 108 and the auxiliary wiring 106 are formed on the counter substrate 121 side so as to be aligned with the position of the insulating layer 101 side where the insulating layer 104 is provided. Further, spacers 107 are formed on the insulating layer 104. That is, the spacer 107, the spacer 108, and the auxiliary wiring 106 are formed so as to be disposed between two sub-pixels. The counter substrate 121 and the insulating layer 101 are bonded to each other with the adhesive layer 103 so that the auxiliary wiring 106 is in contact with the common electrode 113.

Fig. 26B shows a top view of the display panel. The display panel includes a pixel portion 71, a visible light transmission region 72, and a region 73 (routing wiring) which shields visible light. The cross sections of three portions in the pixel portion 71 are observed. As shown in fig. 27A to 27C, it was confirmed that: in any of the above three portions, the auxiliary wiring 106 is in contact with the common electrode 113.

[ example 2]

In this example, a result of manufacturing a display device according to one embodiment of the present invention is described.

[ preservation test of display Panel ]

Flexible displays sometimes deform due to temperature changes and humidity changes. Then, as shown in fig. 28A and 28B, a storage test was performed by bonding a display panel 190 as a flexible display to a support 195.

The display panel 190 includes the visible light transmission regions 72 along both sides, similarly to the display panel DP shown in fig. 12A. At least a part of the visible light transmission region 72 overlaps with other display panels and therefore does not overlap with the support 195.

As shown in fig. 28A, in the comparative sample (Ref), the display panel 190 is fixed to the support 195 by attaching the display panel 190 to only four sides around the support 195 and the vicinity thereof. As shown in fig. 28B, in the Sample (Sample), the display panel 190 was attached to one surface of the support 195 and the display panel 190 was fixed to the support 195. An aluminum plate having a Coefficient of Thermal Expansion (CTE) of 24 ppm/DEG C was used as the support 195.

In the storage test, the samples and the comparative samples were stored at 30 ℃ for 12 hours and then at 0 ℃ for 12 hours.

Fig. 28C shows a comparative Sample (Ref) before the preservation test, and fig. 28D shows a Sample (Sample) before the preservation test. Fig. 28E shows the comparative Sample (Ref) after the preservation test, and fig. 28F shows the Sample (Sample) after the preservation test.

As shown in fig. 28E, wrinkles were generated on the display surface of the comparative sample (Ref) after the preservation test. On the other hand, as shown in fig. 28D and 28F, no difference was observed between the Sample before the preservation test (Sample) and the Sample after the preservation test (Sample).

Accordingly, it is understood that the display panel 190 is bonded to the entire surface of the support 195, thereby suppressing the change in shape of the flexible display.

Further, the display panel was bonded to the entire surface of the support having a CTE different from that of the sample, and the same storage test as described above was performed. When an acrylic plate having a CTE of 70 ppm/c is used, wrinkles are generated on the display surface even if the display panel 190 is attached to the entire surface of the support 195. On the other hand, when a Glass Fiber Reinforced Plastic (GFRP) sheet having a CTE of 60 ppm/DEG C in the resin sheet is used, the occurrence of wrinkles on the display surface is suppressed.

As described above, the flexible display is bonded to the entire surface of the support having a small CTE, whereby the change in shape of the flexible display can be further suppressed.

In addition, a shape change of the flexible display sometimes occurs due to water absorption of the film for the flexible display. It was confirmed that the display panel 190 shown in fig. 28A and 28B has a portion which does not overlap with the support 195, and this portion is more likely to be swollen by absorption than the other portions, and wrinkles are more likely to occur. From this, it is found that a film having a low absorption rate is preferably used.

[ method of bonding display Panel ]

When a plurality of display panels are arranged, an alignment mechanism may be used to finely adjust the positions of the plurality of display panels. On the other hand, when the alignment mechanism is used, a space for the alignment mechanism is required, which leads to an increase in size of the display device and even an increase in size of the electronic apparatus. Accordingly, jigs for bonding display panels to support bodies with high accuracy are manufactured so that a plurality of display panels can be arranged at desired positions without using an alignment mechanism.

A method and jig for bonding the display panel 190 to the support 195 with high accuracy will be described with reference to fig. 29A, 29B, 29C1, 29C2, and 29D.

The jig shown in fig. 29A includes a plurality of panel brackets 416. The jig includes a suction hole at a portion overlapping the panel holder 416, and the display panel 190 can be vacuum-sucked by turning on the switch 417. Also, the panel holder 416 may press the display panel 190 from above. In this manner, by using the panel holder 416, the side (long side in the present embodiment) of the display panel 190 that does not overlap the support 195 can be fixed.

First, the release film of the double-sided tape bonded to the support 195 is peeled off, and the double-sided tape is bonded to the entire one surface of the support 195. Note that the release film to be attached to the display panel side was not peeled off. As shown in fig. 29A, the support 195 to which the double-sided tape is attached is disposed at a predetermined position in the jig.

Next, as shown in fig. 29B, the display panel 190 is disposed on the support 195. The display panel 190 is placed in contact with the adjuster 415, and the display panel 190 is arranged along the broken line shown in fig. 29B. Then, the display panel 190 is sucked by the on switch 417, and the display panel 190 is pressed from above by using the panel holder 416.

Next, as shown in fig. 29C1 and 29C2, in a state where the display panel 190 is lifted up, the display panel 190 is gradually attached to the support 195 from the side where the display panel 190 is fixed (the side of the panel holder 416) while the release film is peeled off. Here, in order to attach the display panel 190 to the support 195 with high accuracy, it is important to peel off the release film from the side where the display panel 190 is fixed by the panel holder 416.

Fig. 29D shows a state where the display panel 190 is attached to the support 195 and detached from the jig. The calculation result of the deviation in the θ direction was about 0.02 ° or less, and it was confirmed that the degree of the deviation was small. The display panel 190 can be attached to the support 195 with high accuracy by using a jig. Fig. 29E shows a state where the display panel 190 attached to the support 195 displays an image. As shown in fig. 29E, it was confirmed that the display panel 190 bonded to the support 195 can display a normal image.

[ display device ]

Then, four sets of the support and the display panel (2 × 2) bonded with high accuracy with the shape change suppressed were manufactured to produce two kinds of display devices.

The first is a multi-screen display in which a display panel and a driving circuit are modularized. Fig. 30 shows a side view of the multi-screen display. Fig. 31A shows the result of the display, and fig. 31B shows a side photograph.

As shown in fig. 30, the display panel 190 is attached to one surface of a support 195 (aluminum plate). The display panel 190 is bonded to the support 195 by the method for bonding a display panel described with reference to fig. 29A, 29B, 29C1, 29C2, 29D, and 29E. The support 195 has a curved surface with a radius of curvature R of 5mm, along which the display panel 190 is curved. The display panel 190 has a portion beyond the support 195. The portion overlaps with the adjacent display panel 190. A drive circuit 372 is fixed to the other surface of the support 195. The display panel 190 and the driving circuit 372 are electrically connected through an FPC 374. Since the support 195 and the display panel 190 are attached to each other with high accuracy, an alignment mechanism is not required, and only the display panel 190 is fixed to a designed frame, and a seamless image can be obtained. The total thickness (thickness T in fig. 30) of the support 195 and the display panel 190 is 35mm or less.

The optical member 240 includes a support member 292, a circularly polarizing plate 295, and an antireflection member 296 in this order from the display panel 190 side. An acrylic plate is used as the support member 292. As the circularly polarizing plate 295, a linearly polarizing plate 295a is located on the viewer side and an 1/4 λ plate 295b is located on the display panel 190 side. An antireflection film (also referred to as an AR film) is used as the antireflection member 296.

Further, the multi-screen display may have a function as a touch panel by incorporating a touch sensor in the display panel 190 or the optical member 240 or attaching a touch panel to the display panel 190 or the optical member 240.

As shown in fig. 31A, the joints of the manufactured multi-screen display are not easily visible, and a natural image is obtained.

The second is a multi-panel display provided with a drive circuit apart from the display panel. First, the structures of three types of display panels will be described with reference to fig. 32 and fig. 33A to 33E.

FIG. 32 is a rear view of the multi-screen display. In the multi-screen display shown in fig. 32, one end of an FPC374s and one end of an FPC374g are connected to the back surfaces of the display panels 190a to 190 d. As in the display panel 15B shown in fig. 17A and 17B, by exposing the conductive layer on the back surface of the display panel, an FPC can be connected to the back surface of the display panel.

The other end of the FPC374s is connected to one end of the long FPC374a, the other end of the FPC374g is connected to one end of the long FPC374b, and the other ends of the FPCs 374a and 374b are connected to the driver circuit (any of the driver circuits 372a to 372 d). In this way, when the power supply lines or the signal lines are guided using a long FPC, only the FPC exists on the back surface of the display panel, and a display using the features of a thin and lightweight display panel can be realized. The display is suitable for a wall display, for example.

Fig. 33A to 33E illustrate display panels having other structures. Fig. 33A and 33C are bottom views of the display panel, fig. 33B and 33D are top views of the display panel, and fig. 33E is a side view of the display device using the display panel shown in fig. 33C and 33D. As shown in fig. 33A and 33B, when the FPC is attached to the display surface side of the display panel 15C, the FPC may be bent toward the back surface side of the display panel 15C. Further, as shown in fig. 33C to 33E, an FPC may be attached to the display surface side of the display panel 15D, and the display panel 15D itself may be bent to the back surface side. It is preferable to bend the connection portion of the FPC of the display panel, or even the connection portion of the IC, toward the back side, because the non-display area of the display panel can be reduced and a display with a narrow frame can be realized. In this way, even if the FPC is connected to the display surface side of the display panel, the power supply lines or the signal lines are guided by using the long FPC, and a display device having the characteristics of a thin and lightweight display panel for use, in which only the FPC is provided on the rear surface side of the display panel, can be manufactured. Note that the bending angle of the FPC and the display panel is not limited to 180 °.

Table 1 shows specifications of a display panel having a pixel structure similar to the pixel 130a shown in fig. 1A, and a common layer of E L layers is formed twice, the display panel includes an auxiliary wiring electrically connected to a common electrode of a light emitting element, the auxiliary wiring 120 has a structure similar to the connection part 122 shown in fig. 1A and 1B, the auxiliary wiring 120 provided in the same layer as the pixel electrode 111 is electrically connected to the common electrode 113, and the display panel includes the pixel shown in fig. 20B.

[ Table 1]

The display panel is bent along the curved surface, as shown in fig. 33C to 33E, and the connection portion of the FPC and the connection portion of the IC of the display panel are bent to the back surface side of the display panel, and the display panel and the support are sandwiched by a pair of acrylic plates, the acrylic plate (support member 292) on the display surface side is provided with a circular polarizing plate 295 and an AR film (anti-reflection member 296) (refer to an optical member 240 of fig. 33E), fig. 34A and 34C show the results of display, fig. 34B shows a side photograph, as shown in fig. 34B, the total thickness T (refer to fig. 33E) of the display panel and the display panel is about 13mm, that is, a display thinner than the first multi-screen display (fig. 31A and 31B) is realized, as shown in fig. 34A and 34C, and the seam of the support is not easily visible, and natural image of the seam of the multi-screen display is obtained.

Further, using one of the display panels, light emission was performed in an area of 4% of the display area, and the measurement result of the luminance at that time was shown. The measurement was performed by a circular polarizer. The luminance when the display is performed using only the display DATA DATA shown in FIG. 20B is 918cd/m²The luminance when the display DATA DATA additional DATA DATA _ W is displayed is 3149cd/m². As a result, it is possible to realize display with high luminance by combining the display DATA and the DATA _ W.

[ example 3]

In this example, the results of estimating the aperture ratio of the pixel of the display panel according to the embodiment of the present invention and the aperture ratio of the pixel of the display panel according to the comparative example are described.

In this example, the pixel 130a shown in fig. 4A is used as a pixel of a display panel according to an embodiment of the present invention, and the pixel 130 shown in fig. 9A is used as a pixel of a display panel according to a comparative example.

In this embodiment, the aperture ratio of the pixel is estimated under the conditions of a screen size of 13 inches in diagonal, a pixel count of 1280(H) × 720(V), a resolution of HD, and a pixel size of 225 μm □, in this embodiment, the aperture ratio of each pixel is estimated when the shortest distance (margin) between the metal mask and the sub-pixel is 10 μm, 15 μm, and 20 μm.

Fig. 35 shows the result of estimating the aperture ratio of a pixel, the abscissa in fig. 35 shows the shortest distance (room) between the metal mask and the sub-pixel, and the ordinate shows the aperture ratio of a pixel, since the common layer included in the E L layer is formed twice in the display panel according to the embodiment of the present invention, the panel is described as "twice-formed (Two-step)" in fig. 35, and on the other hand, since the common layer included in the E L layer is formed once in the display panel according to the comparative example, the panel is described as "once-formed (One-step)" in fig. 35.

The aperture ratio of the pixels of the display panel of the comparative example was estimated to be about 23% to about 52%. On the other hand, the aperture ratio of the pixel of the display panel according to the embodiment of the present invention is estimated to be about 40% to about 65%. From the above results, it is estimated that the aperture ratio of the pixel of the display panel according to the embodiment of the present invention can be higher by about 15% than the aperture ratio of the pixel of the display panel according to the comparative example.

From the results of the present embodiment, it was confirmed that the aperture ratio of the pixel when the common layer included in the E L layer was formed twice can be higher than the aperture ratio of the pixel when the common layer was formed once.

[ example 4]

In this embodiment, a result of manufacturing a display device including a flexible display panel is described. The display device of the present embodiment can be folded in half with its display surface facing inward.

Fig. 36A illustrates a perspective view of the display device. The display device of the present embodiment includes a support 401a, a support 401b, a display panel 402, a support 403a, a support 403b, a gear 404a, a gear 404b, and a housing 405.

The support 401a and the support 401b are positioned on the back surface (surface opposite to the display surface) side of the display panel 402.

The display panel 402 has a portion fixed to the support 401a and a portion fixed to the support 401 b. For example, the display panel 402 may be fixed to the support by using an adhesive (including an adhesive tape or the like) or an adsorption film or the like.

The display panel 402 includes an organic E L element as a light-emitting element, and a transistor for driving as a light-emitting element includes a transistor including a metal oxide in a semiconductor layer, and the display panel 402 has flexibility.

The support 403a and the support 403b are positioned on the display surface side of the display panel 402 so as not to overlap with the display region of the display panel 402 (so as not to overlap with the non-display region). The support 403a is formed using three members, and each member is fixed to the support 401a with screws. Similarly, the support 403b is formed of three members, and each member is fixed to the support 401b with screws. The structure of the supports 403a and 403b is not limited to the structure shown in fig. 36A, and the supports 403a and 403b may be formed using one or more members.

The non-display region of the display panel 402 has a region between the support 401a and the support 403a and a region between the support 401b and the support 403 b.

An FPC, an IC, a battery, and the like can be housed in the housing 405.

Fig. 36B shows an exploded view of the display device of the present embodiment. In fig. 36B, the support 403a, the support 403B, and the like are not illustrated.

The support 401a is connected to the gear 404a, and the support 401b is connected to the gear 404 b. Since the gear 404a and the gear 404b are engaged with each other, the movement of the support 401a and the movement of the support 401b are synchronized, and the shape change of the display device (the shape change from the unfolded state to the folded state) is predetermined. Therefore, the display panel 402 is curved with a predetermined radius of curvature. The display panel 402 can be prevented from being bent at a radius of curvature smaller than a predetermined radius of curvature, and therefore: when the display device is folded, the display panel 402 is applied with an unexpectedly large pressure, which causes breakage of the display panel 402.

When the display device is in the unfolded state, the support 401a and the support 401b are in contact with each other. Therefore, the support 401a and the support 401b can support the entire display panel 402, and the impact strength or scratch hardness of the display panel 402 can be improved.

In the midway state in which the display device is changed from the unfolded state to the folded state, the support 401a and the support 401b are separated from each other, and therefore, a region which is not in contact with the support 401a and the support 401b is generated in the display panel 402. Since the support 401a and the support 401b are not supported, the impact strength and the scratch in this region may be reduced.

In order to increase the impact strength and scratch hardness of the display panel 402, it is preferable to provide an impact-relaxing layer on one surface or both surfaces of the display panel 402. Examples of the material of the impact-relaxing layer include silicone, urethane, and acrylic. The impact-relaxing layer is preferably rubber-like. The impact-relaxing layer may be in the form of a gel. In this example, a display device in which a silicone sheet is disposed only on the display surface of the display panel 402 and a display device in which a urethane sheet is disposed on both surfaces of the display panel 402 were manufactured.

Fig. 37A to 37D show photographs of the display device of the present embodiment. In the display device shown in fig. 37A and 37B, urethane sheets having a thickness of about 0.22mm are disposed on both surfaces of the display panel 402. In the display devices shown in fig. 37C and 37D, a silicone sheet having a thickness of about 0.5mm is disposed on the display surface of the display panel 402. The display of both the display devices was good, and it was confirmed that both the display devices had high endurance.

Description of the symbols

The pixel electrode includes a pixel electrode layer composed of p 1, p 2, p 1, p 2, p 1, p 2, p 1.

The present application is based on japanese patent application No.2017-230849 filed on 30.11.2017 and japanese patent application No.2018-095869 filed on 18.5.2018, which are incorporated herein by reference in their entirety.