阅读说明：本技术 发光二极管显示面板、具有其的显示装置及制造其的方法 (Light emitting diode display panel, display device having the same, and method of manufacturing the same ) 是由 张成逵 李剡劤 申讃燮 李豪埈 于 2020-04-23 设计创作，主要内容包括：根据一实施例的显示面板包括：电路基板,具有垫；发光元件,电连接于所述垫而整齐排列于所述电路基板上；以及缓冲物质层,布置于所述电路基板与所述发光元件之间而填充所述电路基板与所述发光元件之间的空间,其中,所述缓冲物质层位于所述发光元件的上表面的下侧。(A display panel according to an embodiment includes: a circuit substrate having a pad; light-emitting elements electrically connected to the pads and arranged on the circuit substrate in order; and a buffer substance layer disposed between the circuit substrate and the light emitting element to fill a space between the circuit substrate and the light emitting element, wherein the buffer substance layer is located on a lower side of an upper surface of the light emitting element.)

1. A display panel, comprising:

a circuit substrate having a pad;

light-emitting elements electrically connected to the pads and arranged on the circuit substrate in order; and

a buffer substance layer arranged between the circuit substrate and the light emitting element to fill a space between the circuit substrate and the light emitting element,

wherein the buffer substance layer is located on the lower side of the upper surface of the light emitting element.

2. The display panel of claim 1,

the buffer substance layer covers a surface of the circuit substrate between the light emitting elements, and has a plurality of grooves in a region between two light emitting elements.

3. The display panel of claim 1,

each of the light emitting elements includes an electrode pad,

the electrode pad is electrically connected to the pad.

4. The display panel of claim 3, further comprising:

conductive particles arranged between pads on the circuit substrate and electrode pads of the light emitting element,

wherein the pad and the electrode pad are electrically connected through the conductive particles.

5. The display panel of claim 4,

the buffer layer further includes conductive particles spaced apart from each other in regions between the light emitting elements.

6. The display panel of claim 3, further comprising:

and a light blocking substance layer disposed in a region between the light emitting elements to block light emitted through side surfaces of the light emitting elements.

7. The display panel of claim 6,

the light blocking substance layer covers a portion of an upper surface of the buffer substance layer.

8. The display panel of claim 3, further comprising:

a solder layer formed between the pad and the electrode pad,

wherein the pad and the electrode pad are electrically connected through the solder layer.

9. The display panel of claim 1,

a first LED lamination layer, a second LED lamination layer and a third LED lamination layer which emit light with different wavelengths;

the light emitting element includes: an electrode pad electrically connected to the first to third LED stacks; and

a bump pad disposed on the electrode pad,

wherein the bump pad is electrically connected to a pad on the circuit substrate.

10. The display panel according to claim 9,

further comprising a bonding layer between the pads of the circuit substrate and the bump pads,

the bonding layer comprises In, Pb, AuSn, CuSn or solder.

11. The display panel of claim 1,

the buffer substance layer is cured resin, polymer, BCB or SOG.

12. The display panel of claim 1,

the light emitting elements respectively include a first LED lamination layer, a second LED lamination layer and a third LED lamination layer, and the first LED lamination layer to the third LED lamination layer emit light with different wavelengths.

13. The display panel of claim 12,

the light emitting element emits light generated in the first to third LED laminated layers through the third LED laminated layer.

14. The display panel of claim 13,

the third LED stack is separated from the growth substrate.

15. The display panel of claim 1,

the spacing between the light emitting elements is greater than the width of the light emitting elements.

16. The display panel of claim 1,

the buffer substance layer covers the surface of the circuit substrate between the light emitting elements,

the buffer substance layer includes electrically conductive particles,

the conductive particles are more densely arranged in a region between the circuit substrate and the light emitting elements than in a region between the light emitting elements.

17. A display device is a display device including a display panel, wherein,

the display panel includes:

a circuit substrate having a pad;

light-emitting elements electrically connected to the pads and arranged on the circuit substrate in order; and

a buffer substance layer arranged between the circuit substrate and the light emitting element to fill a space between the circuit substrate and the light emitting element,

wherein the buffer substance layer is located on the lower side of the upper surface of the light emitting element.

18. The display device according to claim 17,

the buffer substance layer covers a surface of the circuit substrate between the light emitting elements, and has a plurality of grooves in a region between two light emitting elements.

19. The display device according to claim 17,

each of the light emitting elements includes an electrode pad,

the electrode pad is electrically connected to the pad.

20. The display device according to claim 17,

the light emitting elements include a first LED stack, a second LED stack, and a third LED stack, respectively, and the first to third LED stacks emit light of different wavelengths from each other,

the light emitting element emits light generated in the first to third LED laminated layers through the third LED laminated layer.

21. The display device according to claim 17, further comprising:

and a light blocking substance layer disposed in a region between the light emitting elements to block light emitted through side surfaces of the light emitting elements.

Technical Field

The present invention relates to a light emitting diode display panel capable of securely transferring a plurality of light emitting elements for display, a display device having the same, and a method of manufacturing the same.

Background

Light emitting diodes are used as inorganic light sources in various fields such as display devices, vehicle lamps, and general lighting. Light emitting diodes have the advantages of long life, low power consumption, and fast response speed, and are therefore rapidly replacing existing light sources.

In addition, conventional light-emitting elements are mainly used as backlights in display devices. However, recently, LED displays for directly implementing images using light emitting diodes are being developed.

Display devices generally realize various colors by using a mixture of blue, green, and red colors. The display device includes a plurality of pixels in order to realize various images, each pixel is provided with sub-pixels of blue, green, and red, and the color of a specific pixel is determined by the colors of the sub-pixels, and an image is realized by a combination of the pixels.

The LED may emit light of various colors according to its material, so that a display device may be provided by arranging individual LED chips emitting blue, green, and red colors on a two-dimensional plane.

After the LEDs used in the existing large electronic screen are manufactured into packages, the LED packages are arranged in order in pixel units, and thus, a single package is attached to the circuit substrate. However, in order to achieve a clear image quality, a display of a small electronic product such as a smart watch, a mobile phone, a VR helmet, AR glasses, or the like, or a display of a TV, or the like, needs to be mounted with a micro LED having a smaller size than a conventional LED package.

Since the small-sized LED is difficult to handle, it is difficult to individually attach the LED to the circuit substrate. Therefore, a method of forming a plurality of LEDs using a semiconductor layer grown on a substrate and collectively transferring them onto a display circuit substrate corresponding to a pixel interval is being studied. However, if a failure occurs in some of the LEDs while the plurality of LEDs are collectively transferred, it is difficult to replace them. In particular, when the LED is separated from the growth substrate by a technique such as laser lift-off, a defect such as a crack may occur in the LED due to an impact caused by the laser. Therefore, there is a need for a display device capable of safely transferring collectively transferred LEDs to a circuit substrate without causing defects.

In addition, since the sub-pixels are arranged on a two-dimensional plane, the area occupied by one pixel including the blue, green, and red sub-pixels is relatively large. Therefore, in order to arrange the sub-pixels within a limited area, the area of each LED chip must be reduced. However, reducing the size of the LED chip may cause difficulty in mounting the LED chip, resulting in a reduction in light emitting area.

Disclosure of Invention

Technical problem

The present invention addresses the problem of providing an LED display device that can safely transfer a plurality of light-emitting elements to a circuit board.

Another object of the present invention is to provide a light-emitting element transfer method capable of easily transferring light-emitting elements manufactured on a wafer collectively to a circuit board.

Another object of the present invention is to provide a method of securely transferring a light emitting element for display, which can increase the area of each sub-pixel within a limited pixel area, and a display device.

Technical scheme

A display panel according to an embodiment of the present invention includes: a circuit substrate having a pad; light-emitting elements electrically connected to the pads and arranged on the circuit substrate in order; and a buffer substance layer disposed between the circuit substrate and the light emitting element to fill a space between the circuit substrate and the light emitting element, wherein the buffer substance layer is located on a lower side of an upper surface of the light emitting element.

A display device according to an embodiment of the present invention includes a display device of a display panel including: a circuit substrate having a pad; light-emitting elements electrically connected to the pads and arranged on the circuit substrate in order; and a buffer substance layer disposed between the circuit substrate and the light emitting element to fill a space between the circuit substrate and the light emitting element, wherein the buffer substance layer is located on a lower side of an upper surface of the light emitting element.

Drawings

Fig. 1 is a schematic perspective view for explaining a display device according to an embodiment of the present invention.

Fig. 2 is a schematic plan view for explaining a display panel according to an embodiment of the present invention.

Fig. 3 is a schematic enlarged sectional view taken along a section line a-a of fig. 2.

Fig. 4 is a schematic plan view for explaining a light emitting element according to an embodiment of the present invention.

Fig. 5 is a schematic sectional view taken along a section line B-B of fig. 4 for explaining a light emitting element according to an embodiment of the present invention.

Fig. 6 is a schematic circuit diagram for explaining a light emitting element according to an embodiment of the present invention.

Fig. 7 is a schematic circuit diagram for explaining a light emitting element according to still another embodiment of the present invention.

Fig. 8 is a schematic plan view for explaining a light emitting element according to still another embodiment of the present invention.

Fig. 9 is a schematic sectional view taken along a cut-off line C-C of fig. 8 for explaining a light emitting element according to still another embodiment of the present invention.

Fig. 10 is a schematic circuit diagram for explaining a light emitting element according to still another embodiment of the present invention.

Fig. 11 is a schematic circuit diagram for explaining a light emitting element according to still another embodiment of the present invention.

Fig. 12a, 12b, 12c, 12d, and 12e are schematic cross-sectional views for explaining a method of manufacturing a display panel according to an embodiment of the present invention.

Fig. 13a, 13b, 13c, 13d, and 13e are schematic cross-sectional views for explaining a method of manufacturing a display panel according to still another embodiment of the present invention.

Fig. 14a, 14b, 14c, and 14d are schematic cross-sectional views for explaining a method of manufacturing a display panel according to still another embodiment of the present invention.

Fig. 15a, 15b, 15c, and 15d are schematic cross-sectional views for explaining a method of manufacturing a display panel according to still another embodiment of the present invention.

Fig. 16a, 16b, 16c, 16d and 16e are schematic cross-sectional views for explaining a method of manufacturing a display panel according to still another embodiment of the present invention.

Fig. 17a, 17b, 17c, 17d, and 17e are schematic cross-sectional views for explaining a method of manufacturing a display panel according to still another embodiment of the present invention.

Fig. 18a, 18b, 18c, and 18d are schematic cross-sectional views for explaining a method of manufacturing a display panel according to still another embodiment of the present invention.

Best mode for carrying out the invention

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below are provided as examples in order to fully convey the concept of the present invention to those skilled in the art to which the present invention pertains. Therefore, the present invention is not limited to the following embodiments, and may be embodied in other forms. In the drawings, the widths, lengths, thicknesses, and the like of the components may be exaggerated for convenience. When a description is made that one component is located "on" or "above" another component, the description includes not only a case where each part is located "directly on" or "above" another part, but also a case where another component is interposed between each component and another component. Like reference numerals denote like constituent elements throughout the specification.

A display panel according to an embodiment of the present invention includes: a circuit substrate having a pad; light-emitting elements electrically connected to the pads and arranged on the circuit substrate in order; and a buffer substance layer disposed between the circuit substrate and the light emitting element to fill a space between the circuit substrate and the light emitting element, wherein the buffer substance layer is located on a lower side of an upper surface of the light emitting element.

By filling the space between the light emitting elements with the buffer substance layer, the impact applied to the light emitting elements when the light emitting elements are transferred to the circuit substrate can be relieved. Accordingly, the light emitting elements can be safely and collectively transferred to the circuit substrate.

The buffer substance layer may cover a surface of the circuit substrate between the light emitting elements, and may have a plurality of grooves in a region between two light emitting elements.

In an embodiment, each light emitting element may include an electrode pad, which may be electrically connected to the pad. Further, the groove may have a shape corresponding to a shape of the electrode pad.

In an embodiment, the display panel may further include: and conductive particles arranged between pads on the circuit substrate and electrode pads of the light emitting element, wherein the pads and the electrode pads can be electrically connected through the conductive particles.

Further, the buffer substance layer may further include conductive particles spaced apart from each other in a region between the light emitting elements.

In addition, the display panel may further include: and a light blocking substance layer disposed in a region between the light emitting elements to block light emitted through side surfaces of the light emitting elements.

The contrast of the display panel can be improved by the light blocking substance layer.

The light blocking substance layer may cover a portion of an upper surface of the buffer substance layer.

In an embodiment, the display panel may further include: and a solder layer formed between the pad and the electrode pad, wherein the pad and the electrode pad may be electrically connected through the solder layer.

In addition, the light emitting element may include: a first LED lamination layer, a second LED lamination layer and a third LED lamination layer which emit light with different wavelengths; an electrode pad electrically connected to the first to third LED stacks; and a bump pad disposed on the electrode pad, wherein the bump pad may be electrically connected to a pad on the circuit substrate. The plurality of grooves may have a shape corresponding to a shape of the protrusion pad.

Furthermore, the display panel may further include a bonding layer between the pads of the circuit substrate and the bump pads, and the bonding layer may include In, Pb, AuSn, CuSn, or solder.

The buffer layer may be a cured resin, polymer, BCB, or SOG.

The light emitting elements may include first, second, and third LED stacked layers, respectively, and the first to third LED stacked layers may emit light of different wavelengths from each other.

The light emitting element can emit light generated by the first to third LED laminated layers through the third LED laminated layer.

Additionally, the third LED stack may be an LED stack separated from the growth substrate. That is, the light emitting element may not include a growth substrate used for growing the third LED stack.

In one embodiment, the spacing between the light emitting elements may be greater than the width of the light emitting elements.

In addition, the buffer substance layer may cover a surface of the circuit substrate between the light emitting elements, and the buffer substance layer may include conductive particles. Further, the conductive particles may be more densely arranged in a region between the circuit substrate and the light emitting elements than in a region between the light emitting elements.

A display device according to an embodiment of the present invention includes a display panel including: a circuit substrate having a pad; light-emitting elements electrically connected to the pads and arranged on the circuit substrate in order; and a buffer substance layer disposed between the circuit substrate and the light emitting element to fill a space between the circuit substrate and the light emitting element, wherein the buffer substance layer is located on a lower side of an upper surface of the light emitting element.

The buffer substance layer may cover a surface of the circuit substrate between the light emitting elements, and may have a plurality of grooves in a region between two light emitting elements.

In addition, each light emitting element may include an electrode pad, which may be electrically connected to the pad.

In an embodiment, the groove may have a shape corresponding to a shape of the electrode pad.

The light emitting elements may include a first LED stack, a second LED stack, and a third LED stack, and the first to third LED stacks may emit light having different wavelengths from each other, and the light emitting elements may emit light generated in the first to third LED stacks through the third LED stack.

In an embodiment, the third LED stack may be a LED stack separated from the growth substrate. In another embodiment, the display device may further include a growth substrate disposed on the third LED stack.

The display device may further include: and a light blocking substance layer disposed in a region between the light emitting elements to block light emitted through side surfaces of the light emitting elements.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

Fig. 1 is a schematic perspective view for explaining a display device according to an embodiment of the present invention.

The light emitting element of the present invention is not particularly limited, but may be used in particular in a smart watch 1000a, a VR display device such as a virtual reality helmet (VR headset)1000b, or an AR display device such as augmented reality glasses 1000 c.

The display device is internally attached with a display panel used for presenting images. Fig. 2 is a schematic plan view for explaining a display panel 1000 according to an embodiment of the present invention, and fig. 3 is a sectional view taken along a cut-off line a-a of fig. 2.

Referring to fig. 2 and 3, the display panel includes a circuit substrate 1001, a light-emitting element 100, and a buffer substance layer 1005.

The circuit substrate 1001 or the panel substrate may include a circuit for passive matrix driving or active matrix driving. In one embodiment, the circuit substrate 1001 may include wiring and resistors therein. In another embodiment, the circuit substrate 1001 may include a wiring, a transistor, and a capacitor. The circuit substrate 1001 may also have pads 1003 on the upper surface for allowing electrical connection to circuits arranged inside.

The plurality of light emitting elements 100 are arranged in order on the circuit board 1001. The light-emitting element 100 may be a small-sized light-emitting element having a micro unit size, and the width W1 may be 300 μm or less, further 200 μm or less, and more specifically 100 μm or less. The light-emitting element 100 may have a size of 200 μm × 200 μm or less, for example, and may further have a size of 100 μm × 100 μm or less. In one embodiment, in the direction in which the light emitting elements 100 are aligned, the interval L1 between the light emitting elements 100 may be greater than the width W1 of the light emitting elements 100 in the interval direction.

The light-emitting element 100 has electrode pads 101, and the electrode pads 101 are electrically connected to the circuit board 1001. For example, the electrode pads 101 may be bonded to pads 1003 exposed on the circuit substrate 1001. The electrode pads 101 may have the same size as each other or different sizes from each other. The electrode pads 101 may have a relatively large area, and the maximum width of each electrode pad may be about 1/4 to about 3/4 or less of the maximum width of the light emitting element 100. In addition, the minimum width of each electrode pad may be about 1/5 to about 3/4 or less of the minimum width of the light emitting element 100. The interval between the electrode pads 101 may be about 3 μm or more, specifically 5 μm or more, and further 10 μm or more.

Each light emitting element 100 constitutes one pixel. For example, each light emitting element 100 may include blue, green, and red sub-pixels.

A specific configuration of the light-emitting element 100 will be described with reference to fig. 4, 5, and 6. Fig. 4 is a schematic plan view for explaining the light emitting element 100 according to an embodiment of the present invention, fig. 5 is a schematic sectional view taken along a cut-off line B-B of fig. 4 for explaining the light emitting element 100 according to an embodiment of the present invention, and fig. 6 is a schematic circuit diagram for explaining the light emitting element 100 according to an embodiment of the present invention. For convenience of explanation, fig. 4 and 5 illustrate and explain a case where the electrode pads 101a, 101b, 101c, 101d are disposed on the upper side, but the light emitting element 100 is flip-chip bonded to the circuit substrate 1001 as illustrated in fig. 3, in which case the electrode pads 101a, 101b, 101c, 101d are disposed on the lower side.

First, referring to fig. 4 and 5, the light emitting element 100 may include a first LED stack 23, a second LED stack 33, a third LED stack 43, a first bonding layer 30, a second bonding layer 40, a first insulating layer 51, and electrode pads 101a, 101b, 101c, 101 d.

The first LED stack 23, the second LED stack 33, and the third LED stack 43 may be formed using semiconductor layers grown on different growth substrates, respectively, and all the growth substrates may be removed from the first LED stack 23, the second LED stack 33, and the third LED stack 43. Therefore, the light emitting element 100 may not include a substrate used for growing the first LED stack 23, the second LED stack 33, and the third LED stack 43. However, the present invention is not limited to this, and at least one growth substrate may remain without being removed.

In the embodiment of the present invention, the first LED stack 23, the second LED stack 33, and the third LED stack 43 are stacked in the vertical direction. The first LED stack 23, the second LED stack 33 and the third LED stack 43 each comprise a first conductivity type semiconductor layer 23a, 33a, 43a, a second conductivity type semiconductor layer 23c, 33c, 43c and an active layer 23b, 33b, 43b interposed therebetween. The active layer may particularly have a multiple quantum well structure.

A second LED stack 33 is arranged below the first LED stack 23 and a third LED stack 43 is arranged below the second LED stack 33. For convenience of explanation, a case where the second LED stack 33 is disposed below the first LED stack 23 and the third LED stack 43 is disposed below the second LED stack 33 is explained in this specification, but it is to be noted that the light emitting element may be flip-chip bonded, and thus the up-down positions of these first to third LED stacks may be interchanged.

The light generated in the first LED stack 23, the second LED stack 33, and the third LED stack 43 is finally emitted to the outside through the third LED stack 43. Thus, the first LED stack 23 emits light at a longer wavelength than the second LED stack 33 and the third LED stack 43, and the second LED stack 33 emits light at a longer wavelength than the third LED stack 43. For example, the first LED stack 23 may be a red emitting inorganic light emitting diode, the second LED stack 33 may be a green emitting inorganic light emitting diode, and the third LED stack 43 may be a blue emitting inorganic light emitting diode. The first LED stack 23 may include a well layer of AlGaInP series, the second LED stack 33 may include a well layer of AlGaInP series or AlGaInN series, and the third LED stack 43 may include a well layer of AlGaInN series.

Since the first LED stack 23 emits light of a longer wavelength than the second LED stack 33 and the third LED stack 43, the light generated in the first LED stack 23 can be transmitted through the second LED stack 33 and the third LED stack 43 and emitted to the outside. Further, since the second LED stack 33 emits light of a longer wavelength than the third LED stack 43, the light generated in the second LED stack 33 can be transmitted through the third LED stack 43 and emitted to the outside.

In each of the LED stacks 23, 33, and 43, the first conductive type semiconductor layers 23a, 33a, and 43a are n-type semiconductor layers, and the second conductive type semiconductor layers 23c, 33c, and 43c are p-type semiconductor layers. In the present embodiment, the first LED stack 23, the second LED stack 33, and the third LED stack 43 are illustrated as having the first conductive type semiconductor layer on all of the lower surfaces thereof and the second conductive type semiconductor layer on all of the upper surfaces thereof, but the order of at least one LED stack may be changed. For example, the top surface of the first LED stack 23 may be the first-type semiconductor layer 23a, and the top surfaces of the second LED stack 33 and the third LED stack 43 may be all the second-conductivity-type semiconductor layers 33c and 43 c.

In the present embodiment, the first LED stack 23, the second LED stack 33, and the third LED stack 43 overlap each other. Also, as shown, the first LED stack 23, the second LED stack 33, and the third LED stack 43 may have substantially the same size of light emitting area. However, since the first LED stack 23 and the second LED stack 33 may have through holes for allowing electrical connection, they may have a smaller light emitting area than the second LED stack 33.

The first bonding layer 30 bonds the first LED stack 23 to the second LED stack 33. The first bonding layer 30 may be disposed between the first-type semiconductor layer 23a and the second-conductivity-type semiconductor layer 33 c. The first bonding layer 30 may be formed using a transparent organic layer, or may be formed using a transparent inorganic layer. The organic layer may be, for example, SU8, poly (methyl methacrylate), polyimide, parylene, Benzocyclobutene (BCB), or the like, and the inorganic layer may be, for example, Al₂O₃、SiO₂、SiN_xAnd the like. Also, the first bonding layer 30 may also be formed using Spin On Glass (SOG).

The second bonding layer 40 bonds the second LED stack 33 to the third LED stack 43. As shown, the second bonding layer 40 may be disposed between the first-type semiconductor layer 33a and the second conductive type semiconductor layer 43 c. The second bonding layer 40 may be formed using the same material as that described above with respect to the first bonding layer 30, and a detailed description is omitted to avoid redundancy.

The first insulating layer 51 may cover the first LED stack 23. The first insulating layer 51 may cover the side surfaces of the first LED stack 23, the second LED stack 33, and the third LED stack 43. The first insulating layer 51 may be formed using a silicon oxide film or a silicon nitride film.

Electrode pad 101: 101a, 101b, 101c, 101d may be arranged on the first insulating layer 51. The electrode pads 101a, 101b, 101c, 101d may be electrically connected to the first LED stack 23, the second LED stack 33, and the third LED stack 43 through the first insulating layer 51.

Referring to fig. 6, electrode pads 101a, 101b, and 101c may be electrically connected to anodes of the first LED stack 23, the second LED stack 33, and the third LED stack 43, respectively, and an electrode pad 101d is commonly connected to cathodes of the first LED stack 23, the second LED stack 33, and the third LED stack 43. In order to electrically connect the electrode pads 101a, 101b, and 101c to the anodes of the first LED stack 23, the second LED stack 33, and the third LED stack 43, a transparent electrode may be formed on at least one of the second conductive type semiconductor layers 23c, 33c, and 43c of the first LED stack 23, the second LED stack 33, and the third LED stack 43.

In addition, in the present embodiment, the description has been given of the case where the electrode pad 101d is commonly connected to the cathodes of the first LED stack 23, the second LED stack 33, and the third LED stack 43, but as shown in fig. 7, the electrode pad 101d may be commonly connected to the anodes of the first LED stack 23, the second LED stack 33, and the third LED stack 43. In this case, the electrode pads 101a, 101b, 101c may be connected to cathodes of the first, second, and third LED stacks 23, 33, 43, respectively.

In the present embodiment, the first LED stack 23, the second LED stack 33 and the third LED stack 43 may be driven individually through the electrode pads 101a, 101b, 101c, 101 d. For stable electrical connection, the electrode pads 101a, 101b, 101c, 101d may be formed to have a relatively large area. For example, the electrode pads 101a, 101b, 101c, 101d may have an area greater than 1/4 of the upper surface of the light emitting element 100, respectively.

Referring again to fig. 2 and 3, a buffer substance layer 1005 fills a region between the light-emitting element 100 and the circuit substrate 1001. Further, the buffer substance layer 1005 may cover the circuit substrate 1001 between the light emitting elements 100. The buffer material layer 1005 may cover the side surface of the electrode pad 101 and be attached to the lower surface of the light emitting element 100. The upper surface of the buffer substance layer 1005 is located substantially below the upper surface of the light emitting element 100. A part of the buffer material layer 1005 may partially cover the side surface of the light-emitting element 100. However, a part of the buffer material layer 1005 covering the side surface of the light emitting element does not exceed the height of the upper surface of the light emitting element 100.

As shown in fig. 3, the buffer substance layer 1005 may include conductive particles 1005a, 1005b dispersed in a matrix. The conductive particles 1005a are arranged apart from each other in the region between the pads 1003, and thus do not provide an electrical path. The conductive particles 1005a may have a substantially spherical shape, but are not necessarily limited thereto.

In addition, conductive particles 1005b are arranged between the pad 1003 and the electrode pad 101 to electrically connect them. The conductive particles 1005b may be pressed by pressure to have a shape having a width in a horizontal direction greater than a thickness in a vertical direction. The conductive particles 1005b may be spaced apart from each other, but may also be in contact with each other.

The conductive particles 1005a and 1005b may be, for example, metal particles such as Ni, Au, and Sn, conductive nanoparticles such as nanotubes or nanowires, or the like. The conductive particles 1005a and 1005b may be formed by coating polymer particles with a metal layer.

Since the conductive particles of polymer coated with a metal layer are easily deformed by pressure, it is suitable to electrically connect them between the pad 1003 and the electrode pad 101.

Also, the buffer substance layer 1005 may include a matrix transparent to light, but the present invention is not limited thereto. For example, the buffer substance layer 1005 can reflect light or absorb light, and a matrix having a light reflecting property or a matrix having a light absorbing property can be used for this purpose. Alternatively, a light absorbing material such as carbon black or a light scattering material such as silica may be contained in the matrix.

In one embodiment, the buffer material layer 1005 may have grooves 101g concavely formed in regions between the light emitting elements 100. The grooves 101g correspond to the shape of the electrode pads 101. In particular, the groove 101g may be formed by the electrode pad 101. For example, in the case where the light emitting element 100 has four electrode pads 101a, 101b, 101c, 101d as shown in fig. 4, at least four grooves 101g may be formed between two light emitting elements 100. However, the present invention is not limited thereto, and the buffer material layer 1005 may be removed in a region between the light emitting elements 100.

In addition, in an embodiment, the buffer material layer 1005 may be formed by using an Anisotropic Conductive Film (ACF), for example. The conductive particles 1005a may be distributed substantially uniformly over the entire region of the buffer material layer 1005. The conductive particles 1005b are arranged close to each other so as to be more densely arranged than the conductive particles 1005 a.

In another embodiment, the buffer substance layer 1005 may be formed using an Anisotropic Conductive Paste (ACP), and further, the buffer substance layer 1005 may be formed using a self-assembled anisotropic conductive paste (SAP) including solder particles. Therefore, the conductive particles 1005a can be aggregated between the pads 1003 and the electrode pads 101, and the conductive particles 1005a can remain very rarely or not in the region between the light emitting elements 100.

In yet another embodiment, buffer substance layer 1005 may be a non-conductive substance layer that does not include conductive particles 1005a, 1005b, and pad 1003 and electrode pad 101 may be bonded using In, Pb, AuSn, CuSn, or solder bonding. For example, the buffer substance layer 1005 may be formed using Spin On Glass (SOG), BCB, or the like.

Although not shown in fig. 2 and 3, a light-blocking material layer may be disposed in a region between the light-emitting elements 100. The light blocking substance layer absorbs light or reflects light, and thus prevents light interference between the light emitting elements from occurring, thereby improving the contrast of the display. The light-blocking substance layer may also cover the light-emitting element 100. The light blocking material layer will be described in detail later by a display panel manufacturing method.

Fig. 8 is a schematic plan view for explaining a light emitting element 100a according to still another embodiment of the present invention, and fig. 9 is a schematic sectional view taken along a cut-off line C-C of fig. 8.

Referring to fig. 8 and 9, the light emitting element 100a according to the present embodiment is different in that bump pads 103a, 103b, 103c, 103d are respectively added on the electrode pads 101a, 101b, 101c, 101 d. Further, the second insulating layer 61 may cover the first insulating layer 51 and the electrode pads 101a, 101b, 101c, and 101 d. The second insulating layer 61 may be formed using a silicon oxide film or a silicon nitride film.

The second insulating layer 61 may have an opening portion exposing the electrode pads 101a, 101b, 101c, 101d, and the bump pads 103a, 103b, 103c, 103d may be arranged on the exposed electrode pads.

The bump pads 103a, 103b, 103c, 103d may be arranged in the opening portions of the second insulating layer 61, and the upper surfaces of the bump pads may be flat surfaces. For example, the bump pads 103a, 103b, 103c, 103d may be formed of Au/In, for example, Au may be formed to a thickness of 3 μm, and In may be formed to a thickness of about 1 μm. The light emitting element 100 may be bonded to a pad 1003 on the circuit substrate 1001 with In. In the present embodiment, although the case of bonding a bump pad with In is described, bonding with Pb or AuSn is not limited to In.

In the present embodiment, the case where the upper surfaces of the bump pads 103a, 103b, 103c, 103d are flat is explained and illustrated, but the present invention is not limited thereto. For example, the upper surfaces of the bump pads 103a, 103b, 103c, and 103d may be irregular surfaces, and a part of the bump pads may be located on the second insulating layer 61.

As shown in fig. 10, the first LED stack 23 can be electrically connected to the bump pads 103a, 103d, the second LED stack 33 is electrically connected to the bump pads 103b, 103d, and the third LED stack 43 is electrically connected to the bump pads 103c, 103 d. That is, the cathodes of the first LED stack 23, the second LED stack 33, and the third LED stack 43 are electrically connected to the bump pad 103d in common, and the anodes are electrically connected to the bump pads 103a, 103b, and 103c, respectively. Thus, the first LED stack 23, the second LED stack 33, and the third LED stack 43 can be driven independently.

As shown in fig. 11, anodes of the first LED stack 23, the second LED stack 33, and the third LED stack 43 may be electrically connected to the bump pad 103d in common, and cathodes may be electrically connected to the bump pads 103a, 103b, and 103c, respectively.

Hereinafter, a method of manufacturing the display panel will be described, and accordingly, the structure of the display panel 1000 will be understood in more detail.

In the case where the light emitting element 100 is to be transferred to the circuit substrate 1001, the bump pads 103a, 103b, 103c, 103d may be connected to the pads 1003 of the circuit substrate 1001.

Fig. 12a, 12b, 12c, 12d, and 12e are schematic cross-sectional views for explaining a method of manufacturing a display panel according to an embodiment of the present invention.

Referring to fig. 12a, a plurality of light emitting elements 100 are formed on a substrate 41. The light emitting element 100 includes electrode pads 101. Since the light-emitting element 100 is the same as that described with reference to fig. 4 and 5, detailed description thereof is omitted to avoid redundancy.

The substrate 41 may be a growth substrate for growing the semiconductor layers 43a, 43b, 43c of the third LED stack 43. For example, the substrate 41 may be a gallium nitride substrate, a SiC substrate, a sapphire substrate, or a patterned sapphire substrate.

The second LED stack 33 may be bonded to the third LED stack 43 by a second bonding layer 40 and the first LED stack 23 may be bonded to the second LED stack 33 by a first bonding layer 30.

In an embodiment, after bonding the first LED stack 23, the second LED stack 33, and the third LED stack 43, a patterning process may be performed to separate into a plurality of light emitting element regions. Next, the first insulating layer 51 and the electrode pad 101 may be formed. Although not shown and described in detail, in order to electrically connect the electrode pad 101 to the first LED stack 23, the second LED stack 33, and the third LED stack 43, through holes may be formed in the first LED stack 23 and the second LED stack 33, and the second conductive type semiconductor layer 43c and the active layer 43b of the third LED stack 43 may be partially patterned. As described above, the transparent electrode may be formed on the second conductive type semiconductor layers 23c, 33c, and 43c of the first LED stack 23, the second LED stack 33, and the third LED stack 43.

Referring to fig. 12b, an anisotropic conductive film 1005 is attached to the circuit substrate 1001 having the pads 1003 formed in the pixel regions. The anisotropic conductive film 1005 includes conductive particles 1005a and 1005b in a matrix. An anisotropic conductive film 1005 covers the pads 1003 on the circuit substrate 1001. The conductive particles 1005b in the anisotropic conductive film 1005 are located on the pad 1003.

Here, the conductive particles 1005a indicate conductive particles located outside the upper region of the pad 1003, and the conductive particles 1005b indicate conductive particles located above the pad 1003. The conductive particles 1005a and 1005b have the same structure and shape. In addition, the thickness of the anisotropic conductive film 1005 located on the upper portion of the pad 1003 is similar to or greater than that of the electrode pad 101.

Referring to fig. 12c, light-emitting element 100 formed on substrate 41 is bonded to pad 1003 via anisotropic conductive film 1005. At this time, the light emitting elements 100 of the substrate 41 may be more densely arranged than the pixel region. Therefore, as shown, a part of the light emitting elements 100 on the substrate 41 may be located between the pixel regions and not bonded to the pads 1003.

The pads 1003 and the electrode pads 101 are electrically connected by conductive particles 1005b in the anisotropic conductive film 1005. The substrate 41 may be pressurized toward the circuit substrate 1001, and thus the conductive particles 1005b may be deformed by the pressure. Further, heat may be applied during bonding of the light-emitting element 100 to the anisotropic conductive film 1005. For example, the matrix of anisotropic conductive films 1005 may be cured by heat.

A part of the anisotropic conductive film 1005 may at least partially fill a gap between the light emitting elements 100, and thus may at least partially cover the side surface of the light emitting element 100.

After the light-emitting element 100 is attached to the anisotropic conductive film 1005, laser light is irradiated to the light-emitting element 100 connected to the pad 1003 through the substrate 41, and the light-emitting element 100 is separated from the substrate 41.

Referring to fig. 12d, when the substrate 41 is separated from the anisotropic conductive film 1005, the light-emitting element 100 connected to the pad 1003 is transferred onto the circuit substrate 1001, and the light-emitting element 100 not irradiated with the laser light is separated from the anisotropic conductive film 1005. Thus, the display panel 1000 is manufactured in which the light-emitting element 100 is bonded to the pixel region of the circuit board 1001.

Further, as the light-emitting element 100 not irradiated with the laser light is separated from the anisotropic conductive film 1005, grooves 101g formed by the electrode pads 101 may be formed on the surface of the anisotropic conductive film 1005.

Further, referring to fig. 12e, a light blocking substance layer 1007 filling a region between the light emitting elements 100 may also be formed. The light blocking substance layer 1007 may cover a side surface of the light emitting element 100, and further, may cover an upper surface of the light emitting element 100. The light blocking substance layer 1007 may cover the buffer substance layer 1005 covering the circuit substrate 1001, and may fill the groove 101 g.

The light blocking substance layer 1007 absorbs or reflects light emitted through the side surface of the light emitting element 100, thereby preventing light interference between the light emitting elements. For this, the light blocking substance layer 1007 may be formed using, for example, a black molding agent such as black epoxy resin or black silicone resin. In another embodiment, the light blocking substance layer 1007 may also be formed using a light reflecting substance such as white epoxy or white silicone.

In the present embodiment, although a case where the light blocking substance layer 1007 covers the upper surface of the light emitting element 100 is illustrated, the light blocking substance layer 1007 may be formed to fill the region between the light emitting elements 100 and expose the upper surface of the light emitting element 100. At this time, the height of the light blocking substance layer 1007 may be uniform with the height of the upper surface of the light emitting element 100.

According to this embodiment, the anisotropic conductive film 1005 is used, so that the impact applied to the light-emitting element 100 during irradiation with laser light for laser lift-off can be reduced by the anisotropic conductive film 1005. That is, the anisotropic conductive film 1005 functions as a buffer material layer for alleviating a shock applied to the light-emitting element 100, and therefore, it is possible to prevent a failure of the element during transfer of the light-emitting element 100.

In this embodiment, although the case where the anisotropic conductive film 1005 is attached to the circuit substrate 1001 side is illustrated and described, the anisotropic conductive film 1005 may be attached to the substrate 41 so as to cover the light-emitting element 100.

In this embodiment, the case where the anisotropic conductive film 1005 is attached to the circuit board 1001 side is described, but an anisotropic conductive paste may be used.

Fig. 13a, 13b, 13c, 13d, and 13e are schematic cross-sectional views for explaining a method of manufacturing a display panel according to still another embodiment of the present invention.

Referring to fig. 13a, as described with reference to fig. 12a, a plurality of light emitting elements 100 are formed on a substrate 41.

Referring to fig. 13b, a self-assembled anisotropic conductive paste (SAP)2005 is formed on the circuit substrate 1001 on which the pads 1003 are formed in each pixel region. The SAP 2005 has a structure in which conductive particles 2005a are dispersed in a resin such as an epoxy resin. The SAP 2005 can be formed on the circuit substrate 1001 by, for example, a screen printing technique.

The conductive particles 2005a may be solder particles, for example. Specifically, the solder particles may contain Sn, and may contain at least one selected from Au, Ag, Bi, Cu, and In. The melting point of the solder particles may be lower than the curing temperature of the resin.

Referring to fig. 13c, the substrate 41 on which the light emitting element 100 is formed is placed on the SAP 2005. No additional pressure needs to be applied to the substrate 41. Next, heat is applied to the SAP 2005. Heat may be applied by the oven using a hot plate, and may also be applied locally using spot heating. As heat is applied to the SAP 2005, the conductive particles 2005a are aggregated at the pad 1003 and the electrode pad 101 to form an aggregated conductive particle layer 2005 c. The temperature at which the conductive particles 2005a are aggregated may be lower than the curing temperature of the resin, and thus the conductive particles are aggregated before the resin is cured.

In addition, a portion of the SAP 2005 may at least partially fill the gap between the light emitting elements 100, and thus may at least partially cover the side between the light emitting elements 100.

As the conductive particles 2005a aggregate, the pad 1003 and the electrode pad 101 are electrically connected. Although the conductive particles 2005a may remain in the region between the light-emitting elements 100, the density decreases as a large number of conductive particles 2005a are aggregated on the pad 1003.

Next, the resin is cured, so that the light emitting element 100 is attached to the SAP 2005. The conductive particle layer 2005c aggregated between the pad 1003 and the electrode pad 101 may retain a particle shape, but the particle shape disappears and becomes a single layer by maintaining a temperature higher than the melting point of the conductive particle 2005 a.

Referring to fig. 13d, thereafter, the light emitting element 100 connected to the pad 1003 is separated from the substrate 41 by a laser lift-off technique of selectively irradiating laser light, so that the light emitting element 100 is transferred to the circuit substrate 1001.

In addition, the light emitting element 100 not connected to the pad 1003 may be separated from the SAP 2005 together with the substrate 41, thereby forming the groove 101g on the surface of the SAP 2005.

Further, referring to fig. 13e, as described with reference to fig. 12e, the light blocking substance layer 1007 may fill the region between the light emitting elements 100. The height of the upper surface of the light blocking substance layer 1007 may be the same as the height of the upper surface of the light emitting element 100. In another embodiment, the light blocking substance layer 1007 may also cover the upper surface of the light emitting element 100.

According to the present embodiment, by using the self-assembled anisotropic conductive paste 2005, the pads 1003 and the electrode pads 101 can be stably electrically connected and an electrical short can be prevented from occurring. Further, since the impact can be relieved by the SAP 2005, it is possible to prevent a defect such as a crack from occurring in the light emitting element 100 due to the impact by the laser lift-off, and thus it is possible to safely and collectively transfer the light emitting element 100 onto the circuit substrate 1001.

Fig. 14a, 14b, 14c, and 14d are schematic cross-sectional views for explaining a method of manufacturing a display panel according to still another embodiment of the present invention.

Referring to fig. 14a, as described with reference to fig. 12a, a plurality of light emitting elements 100 are formed on a substrate 41.

Referring to fig. 14b, an insulating material layer 3005 is formed on the circuit substrate 1001 having the pad 1003. The insulating material layer 3005 may be formed using epoxy, polymer, Spin On Glass (SOG), BCB, or the like. The insulating substance layer 3005 is formed to expose the pad 1003. For example, the insulating material layer 3005 may be patterned by using photolithography and etching techniques.

Referring to fig. 14c, a substrate 41 on which the light emitting element 100 is formed is disposed on a circuit substrate 1001. The pads 1003 and the electrode pads 101 may be bonded to each other by a bonding layer 3007. Bonding layer 3007 may be formed of, for example, AuIn, AuSn, CuSn, Au, Ni, or the like.

The bonding layer 3007 may be formed by forming a bonding substance on the pads 1003 or the electrode pads 101 and bonding the pads and the electrode pads to each other.

Insulating material layer 3005 may be cured after bonding of pads 1003 with electrode pads 101. A portion of the insulating substance layer 3005 may at least partially fill the gap between the light emitting elements 100.

Referring to fig. 14d, the light-emitting element 100 is separated from the substrate 41 by the selective laser lift-off technique and transferred onto the circuit substrate 1001.

Since a part of the light-emitting element 100 is separated from the insulating material layer 3005, the groove 101g can be formed in the surface of the insulating material layer 3005.

Although not shown, as shown in fig. 12e or 13e, the light blocking substance layer 1007 may fill the region between the light emitting elements 100.

According to the present embodiment, an impact applied to the light emitting element 100 during irradiation of laser light can be relieved by the insulating material layer 3005, and therefore, a situation in which a defect such as a crack occurs in the light emitting element 100 can be prevented.

Fig. 15a, 15b, 15c, and 15d are schematic cross-sectional views for explaining a method of manufacturing a display panel according to still another embodiment of the present invention.

Referring to fig. 15a, as described with reference to fig. 12a, a plurality of light emitting elements 100 are formed on a substrate 41.

Referring to fig. 15b, the substrate 41 on which the light emitting element 100 is formed is disposed on the circuit substrate 1001 on which the pad 1003 is formed in the pixel region. The electrode pad 101 of the light emitting element 100 may be bonded to the pad 1003 through the bonding layer 3007. Bonding layer 3007 may be formed of, for example, AuIn, AuSn, CuSn, Au, Ni, or the like. The bonding layer 3007 may be formed by forming a bonding substance on the pads 1003 or the electrode pads 101 and bonding the pads and the electrode pads to each other.

Referring to fig. 15c, a region between the substrate 41 and the circuit substrate 1001 is filled with an insulating substance layer 4005. The insulating material layer 4005 may be formed using epoxy, polymer, BCB, or the like. The insulating material layer 4005 may be in contact with the lower surface of the light emitting element 100, and may cover the side surfaces of the pad 1003 and the electrode pad 101. Further, a part of the insulating substance layer 4005 may at least partially fill a gap between the light emitting elements 100. Next, the insulating substance layer 4005 may be cured.

Referring to fig. 15d, the light-emitting element 100 is separated from the substrate 41 by the selective laser lift-off technique and transferred onto the circuit substrate 1001.

Since a part of the light-emitting element 100 is separated from the insulating material layer 4005, a groove 101g can be formed in the surface of the insulating material layer 4005.

Although not shown, as shown in fig. 12e or 13e, the light blocking substance layer 1007 may fill the region between the light emitting elements 100.

According to the present embodiment, an impact applied to the light emitting element 100 during irradiation of laser light can be relieved by the insulating material layer 4005, and therefore, a situation in which a defect such as a crack occurs in the light emitting element 100 can be prevented.

Fig. 16a, 16b, 16c, 16d and 16e are schematic cross-sectional views for explaining a method of manufacturing a display panel according to still another embodiment of the present invention.

Referring to fig. 16a, as described with reference to fig. 12a, a plurality of light emitting elements 100 are formed on a substrate 41.

Referring to fig. 16b, as described with reference to fig. 14b, an insulating material layer 3005 is formed on the circuit board 1001 having the pads 1003. The insulating material layer 3005 may be formed using epoxy, polymer, Spin On Glass (SOG), BCB, or the like. However, in the present embodiment, the insulating substance layer 3005 may be formed so as to expose not only the pads 1003 but also a part of the circuit substrate 1001. In particular, the insulating substance layer 3005 may be patterned to expose the circuit substrate 1001 in a region between the pads 1003, whereby the opening 3005a may be formed. For example, the insulating material layer 3005 may be patterned by using photolithography and etching techniques.

Referring to fig. 16c, a substrate 41 on which the light emitting element 100 is formed is disposed on the circuit substrate 1001. The pads 1003 and the electrode pads 101 may be bonded to each other by a bonding layer 3007. Bonding layer 3007 may be formed of, for example, AuIn, AuSn, CuSn, Au, Ni, or the like.

The bonding layer 3007 may be formed by forming a bonding substance on the pads 1003 or the electrode pads 101 and bonding the pads and the electrode pads to each other.

Insulating material layer 3005 may be cured after bonding of pads 1003 with electrode pads 101. A part of the insulating substance layer 3005 may cover the side surface between the light emitting elements 100 at least partially.

In addition, the light emitting elements located between the light emitting elements 100 bonded to the circuit substrate 1001 are located on the opening 3005a of the insulating substance layer 3005 on the circuit substrate 1001.

Referring to fig. 16d, the light-emitting element 100 is separated from the substrate 41 by the selective laser lift-off technique and transferred onto the circuit substrate 1001.

In addition, a part of the light-emitting element 100 is removed from the circuit board 1001 together with the substrate 41. Here, since the light emitting element 100 removed together with the substrate 41 is disposed above the opening 3005a of the insulating substance layer 3005, the groove 101g as in the above embodiment is not formed in the insulating substance layer 3005.

Referring to fig. 16e, as described with reference to fig. 12e or 13e, the light blocking substance layer 1007 may fill the region between the light emitting elements 100. The light-blocking substance layer 1007 may cover a part of the upper surface of the insulating substance layer 3005. As described above, the light blocking substance layer 1007 may cover the upper surface of the light emitting element 100.

According to the present embodiment, an impact applied to the light emitting element 100 during irradiation of laser light can be relieved by the insulating material layer 3005, and therefore, a situation in which a defect such as a crack occurs in the light emitting element 100 can be prevented.

Fig. 17a, 17b, 17c, 17d, and 17e are schematic cross-sectional views for explaining a method of manufacturing a display panel according to still another embodiment of the present invention.

Referring to fig. 17a, 17b, 17c, 17d, and 17e, the method for manufacturing a display panel according to the present embodiment is substantially similar to the method for manufacturing a display panel described with reference to fig. 12a, 12b, 12c, 12d, and 12e, but is different in that the anisotropic conductive film 1005 or the anisotropic conductive paste is patterned before the light emitting elements 100 are bonded. Hereinafter, in order to avoid redundant description, the manufacturing method of the present embodiment will be described in detail with respect to the matters different from the above embodiment.

As shown in fig. 17b, the anisotropic conductive film 1005 or the anisotropic conductive paste may be patterned to have an opening 1005c that exposes the surface of the circuit substrate 1001 between the pads 1003. In particular, in the case of using an anisotropic conductive paste, patterning can be performed by a screen printing technique or the like. In another embodiment, the anisotropic conductive film 1005 or the anisotropic conductive paste may be formed using a photosensitive polymer or the like, and then patterned using photolithography or etching.

As shown in fig. 17c, the anisotropic conductive film 1005 or the anisotropic conductive paste may be patterned to have a width greater than that of the light emitting element 100, and thus, the lower surface of the light emitting element 100 may be entirely attached to the anisotropic conductive film 1005 or the anisotropic conductive paste. Further, the side surface of the light-emitting element 100 may be partially covered with the anisotropic conductive film 1005 or the anisotropic conductive paste.

Since the entire lower surface of the light-emitting element 100 is in contact with the anisotropic conductive film 1005 or the anisotropic conductive paste, when the light-emitting element 100 is irradiated with laser light, the impact applied to the light-emitting element 100 can be relieved by the anisotropic conductive film 1005 or the anisotropic conductive paste.

Referring to fig. 17d, the light emitting elements 100 may be transferred onto the circuit substrate 1001, and the circuit substrate 1001 is exposed at the region between the light emitting elements 100. Therefore, unlike the above embodiment, the groove 101g is not formed.

Further, referring to fig. 17e, the region between the light emitting elements 100 may be filled with a light blocking substance layer 1007. In this embodiment, the light blocking substance layer 1007 may be attached to the surface of the circuit substrate 1001. Further, the light blocking substance layer 1007 may partially cover the upper surface of the anisotropic conductive film 1005 or the anisotropic conductive paste. Although not shown, the light blocking material layer 1007 may cover the upper surface of the light emitting element 100 as described with reference to fig. 12 e.

Fig. 18a, 18b, 18c, and 18d are schematic cross-sectional views for explaining a method of manufacturing a display panel according to still another embodiment of the present invention.

The above-described embodiments relate to the case where the light-emitting elements 100 on the substrate 41 are selectively transferred onto the circuit substrate 1001 by the laser lift-off technique to manufacture the display panel. Here, the substrate 41 may be a growth substrate used for growing the third LED stack 43, and may be a sapphire substrate, for example.

However, the present invention is not limited to transferring the light emitting element 100 using the laser lift-off technique. That is, the light emitting elements may be transferred to the circuit board 1001 by a temporary tape after the individual light emitting element chips are rearranged at intervals of the pads 1003 in advance. Fig. 18a, 18b, 18c, and 18d illustrate a method of transferring the light emitting element chips rearranged in advance to the circuit substrate 1001 by a tape (tape).

First, referring to fig. 18a, light-emitting element chips in which light-emitting elements 100 are formed on a substrate 41 are arranged in order on a tape 121. The light-emitting element chips may be aligned so as to correspond to the intervals of the pads 1003 of the circuit board 1001. The tape 121 may also be provided on a temporary substrate (not shown). The light-emitting element chip can be provided by dividing the substrate 41 into individual chip units after the light-emitting elements 100 are formed on the substrate 41.

Referring to fig. 18b, as described with reference to fig. 12b, an anisotropic conductive film 1005 is formed on the circuit board 1001. Instead of the anisotropic conductive film 1005, an anisotropic conductive paste may be used.

Referring to fig. 18c, the light-emitting element chip attached to the tape 121 is bonded to the pad 1003 via an anisotropic conductive film 1005. In this embodiment, since the light emitting element chips are aligned in advance so as to correspond to the pixel region, the light emitting element chips are bonded to the pads 1003 corresponding to the pixel region as shown in the drawing.

The pads 1003 and the electrode pads 101 are electrically connected by conductive particles 1005b in the anisotropic conductive film 1005. The substrate 41 may be pressurized toward the circuit substrate 1001, and thus the conductive particles 1005b may be deformed by the pressure. Heat may be applied during the bonding of the light-emitting element 100 to the anisotropic conductive film 1005. For example, the matrix of anisotropic conductive films 1005 may be cured by heat. At this time, as shown in the figure, a part of the anisotropic conductive film 1005 may cover at least a part of the side surface of the light emitting element 100.

Referring to fig. 18d, the tape 121 is separated from the light emitting elements, and the light emitting element chips are transferred onto the circuit substrate 1001, thereby manufacturing the display panel 1000 in which the light emitting element chips are bonded to the pixel regions of the circuit substrate 1001. Here, the light emitting element chips may include the light emitting element 100 and the substrate 41, respectively.

Further, a light-blocking substance layer may be arranged in a region between the light-emitting element chips. The light blocking material layer may cover the side surface of the light emitting element 100, and further may cover the side surface of the substrate 41. Further, the light blocking material layer may cover the surface of the substrate 41.

In this embodiment, although the case where the light-emitting element chips aligned on the tape 121 are transferred to the circuit board 1001 by the anisotropic conductive film 1005 or the anisotropic conductive paste is described, the present invention is not limited thereto. For example, the above embodiments described with reference to fig. 13a to 13e, 14a to 14d, 15a to 15d, 16a to 16e, and 17a to 17e may be applied with a method of transferring light-emitting element chips aligned on the tape 121.

In the embodiment described above, the case where the electrode pads 101 are connected to the pads 1003 has been illustrated and described, but the present invention is not limited thereto. For example, since the light-emitting element 100a described with reference to fig. 8 and 9 may be transferred to the circuit board 1001, the bump pads 103a, 103b, 103c, and 103d of the light-emitting element 100a may be connected to the pad 1003. In this case, the grooves 101g formed in the buffer substance layers 1005, 2005, 3005, 4005 between the light emitting elements 100 may be formed by the bump pads 103a, 103b, 103c, 103 d.

Various examples of the present invention have been described above, but the present invention is not limited to these examples. Further, matters or constituent elements described in one embodiment may be applied to other embodiments without departing from the scope of the technical idea of the present invention.