阅读说明：本技术 光学装置 (Optical device ) 是由 真野智秀 岩本宜久 于 2021-05-21 设计创作，主要内容包括：提供光学装置,能够切换对光进行反射的状态和出射光的状态,抑制光反射像的显示质量的降低。该光学装置具备：具有光出射面的光出射装置；与所述光出射装置的所述发光面相对配置的吸收型偏光片；配置在所述光出射装置与所述吸收型偏光片之间的液晶光学元件；配置在所述光出射装置与所述液晶光学元件之间的反射型偏光片；以及设置在所述反射型偏光片的朝向所述光出射装置的表面的粘接层。(Provided is an optical device capable of switching between a state of reflecting light and a state of emitting light and suppressing degradation of display quality of a light reflection image. The optical device includes: a light exit device having a light exit face; an absorption type polarizer arranged opposite to the light emitting surface of the light emitting device; a liquid crystal optical element disposed between the light exit device and the absorptive polarizer; a reflective polarizer disposed between the light emitting device and the liquid crystal optical element; and an adhesive layer provided on a surface of the reflection type polarizer facing the light exit device.)

1. An optical device capable of switching between a state of emitting light and a state of reflecting light,

the optical device has:

a light exit device having a light exit face;

an absorption-type polarizer disposed opposite to the light exit surface of the light exit device;

a liquid crystal optical element disposed between the light exit device and the absorptive polarizer;

a reflective polarizer disposed between the light emitting device and the liquid crystal optical element; and

an adhesive layer disposed on a surface of the reflection type polarizer facing the light exit device.

2. The optical device of claim 1,

the adhesive layer adheres the reflection type polarizer and the light exit device.

3. The optical device of claim 1,

the optical device further comprises a light-transmitting plate arranged between the light exit means and the adhesive layer,

the adhesive layer is adhered to the reflection-type polarizer and the light-transmitting plate.

4. The optical device according to any one of claims 1 to 3,

the optical device further includes an optical film attached to a surface of the liquid crystal optical element facing the reflective polarizer.

5. The optical device according to any one of claims 1 to 3,

the light exit device includes:

a liquid crystal display element opposed to the reflective polarizer;

a light source for irradiating the liquid crystal display element with light; and

a polarizing film disposed between the liquid crystal display element and the light source.

6. The optical device of claim 4,

the light exit device includes:

a liquid crystal display element opposed to the reflective polarizer;

a light source for irradiating the liquid crystal display element with light; and

a polarizing film disposed between the liquid crystal display element and the light source.

Technical Field

The present disclosure relates to an optical device capable of switching between a state functioning as a mirror and a state functioning as a display device.

Background

Patent document 1 discloses a device capable of switching between a state functioning as a mirror (also referred to as a state of displaying a mirror image or a state of reflecting external light) and a state functioning as a display device (also referred to as a state of displaying a predetermined image or a state of emitting display light). The device is provided with: a display device that displays a predetermined image; an absorptive polarizer disposed opposite to the display device; a liquid crystal optical element disposed between the display device and the absorptive polarizer; and a reflective polarizer disposed between the display device and the liquid crystal optical element.

[ Prior art documents ]

[ patent document ]

[ patent document 1] patent No. 3419766

Disclosure of Invention

[ problems to be solved by the invention ]

In the device disclosed in patent document 1, the display quality of the mirror image can be greatly reduced due to the fixing method of the reflective polarizer.

The present disclosure has been made in view of the above problems, and a main object thereof is to suppress a reduction in display quality of a light reflection image in an optical device capable of switching between a state of reflected light and a state of emitted light.

[ means for solving problems ]

In order to solve the above problem, an optical device according to an embodiment of the present disclosure is an optical device capable of switching between a state of emitted light and a state of reflected light, the optical device including: a light exit device having a light exit face; an absorption-type polarizer disposed opposite to the light exit surface of the light exit device; a liquid crystal optical element disposed between the light exit device and the absorptive polarizer; a reflective polarizer disposed between the light emitting device and the liquid crystal optical element; and an adhesive layer provided on a surface of the reflection type polarizer facing the light exit device.

[ Effect of the invention ]

According to the optical device having the above configuration, it is possible to suppress a reduction in display quality of the light reflection image.

Drawings

Fig. 1 is a cross-sectional view schematically showing an optical device of a comparative system.

Fig. 2 is a photomicrograph showing defects that may occur in a light reflection image in the comparative mode.

Fig. 3 is a sectional view schematically showing the optical device of embodiment 1.

Fig. 4 is a sectional view schematically showing an optical device according to embodiment 2.

Fig. 5 is a sectional view schematically showing an optical device according to embodiment 3.

Fig. 6 is a cross-sectional view showing an optical device according to a modification of embodiment 1.

Description of the reference symbols

10 light emitting device (organic EL display device)

11 light emergent surface (display surface)

21 reflection type polarizer

22 absorption type polarizer

30 liquid crystal optical element

31f front base plate

31b rear substrate

32f front electrode

32b rear electrode

33f front alignment film

Post 33b alignment film

34 liquid crystal layer

40 cover part

51 to 54 adhesive layer

60 light-transmitting board

70 light emitting device

71 liquid crystal display element

72 light source

73 polarizing film

81, 82 optical film

100 optical device (comparison type)

101 optical device (embodiment 1)

102 optical device (embodiment 2)

103 optical device (embodiment 3)

200 control device

Detailed Description

(comparative mode)

Before describing the embodiments of the present disclosure, a basic configuration and a function of an optical device capable of switching between a state functioning as a mirror and a state functioning as a display device will be described with reference to a comparative embodiment. Such an optical device generally functions as a mirror, and can be used for, for example, interior mirrors and side mirrors for vehicles, which display the interior temperature, the traveling speed, and the like, if necessary.

Fig. 1 shows a comparative optical device 100. Referring to fig. 1, the structure of the optical device 100 will be described first, and the function and operation thereof will be described next.

For convenience, an XYZ rectangular coordinate system including X and Y axes constituting a plane parallel to the horizontal plane and a Z axis orthogonal to the X and Y axes is set. Among the linearly polarized light (electromagnetic wave) traveling along the X axis, the linearly polarized light whose electric field (or magnetic field) vibrates along the Y axis is referred to as Y polarized light, and the linearly polarized light whose electric field (or magnetic field) vibrates along the Z axis is referred to as Z polarized light.

The optical device 100 has a structure in which the following components are arranged in this order: a display device 10 for displaying characters, images, and the like, a reflection type polarizer 21 for reflecting Y-polarized light and transmitting Z-polarized light, for example, a liquid crystal optical element 30 capable of rotating the oscillation direction (polarization direction) of an electric field and a magnetic field in the polarized light, an absorption type polarizer 22 for absorbing Y-polarized light and transmitting Z-polarized light, for example, and a cover member 40 made of a glass member having light permeability.

The display device 10 corresponds to a light emitting device, and is a display device using an organic EL (electro-luminescence) element, for example. Whether or not an image is displayed on the display surface 11 of the display device 10, that is, whether or not the display light Ld is emitted from the display surface 11 is controlled by the control device 200.

The display device 10 may be referred to as a light emitting device that emits the display light Ld. The display surface 11 may be referred to as a light emitting surface.

As the reflective polarizer 21, for example, a wire grid type, a multilayer film type, or the like polarizer may be used. The reflective polarizer 21 is disposed, for example, such that its reflection axis is along the Y axis and its transmission axis is along the Z axis. In the comparative embodiment, the reflective polarizer 21 is bonded to the liquid crystal optical element 30 (rear substrate 31b) via the adhesive layer 51.

The liquid crystal optical element 30 is an optical element capable of rotating the polarization direction of polarized light. Specifically, for example, the optical element can convert Z-polarized light into Y-polarized light. Whether or not to rotate the polarization direction of the polarized light transmitted through the liquid crystal optical element 30 is controlled by the control device 200.

The liquid crystal optical element 30 mainly includes: a rear substrate 31b and a front substrate 31f disposed to face each other; a rear electrode 32b and a front electrode 32f provided on the respective opposing surfaces of the rear substrate 31b and the front substrate 31 f; a rear alignment film 33b and a front alignment film 33f provided on the respective opposing surfaces of the rear electrode 32b and the front electrode 32 f; and a liquid crystal layer 34 interposed between the rear alignment film 33b and the front alignment film 33f, and including liquid crystal molecules having different refractive indices (dielectric constants) depending on directions.

For example, a transparent glass substrate is used as the rear substrate 31b and the front substrate 31 f. For the rear electrode 32b and the front electrode 32f, for example, a light-transmitting conductive member containing indium tin oxide is used.

The rear alignment film 33b and the front alignment film 33f are subjected to uniaxial alignment treatment (e.g., rubbing treatment) using, for example, polyimide. The rear alignment film 33b is subjected to, for example, uniaxial alignment along the Y axis, and the front alignment film 33f is subjected to, for example, uniaxial alignment along the Z axis.

The liquid crystal layer 34 uses, for example, a twisted nematic liquid crystal material.

When no voltage is applied to the liquid crystal layer 34 (normal state), the liquid crystal molecules located near the rear alignment film 33b are aligned along the Y axis, and the liquid crystal molecules located near the front alignment film 33f are aligned along the Z axis. Further, the liquid crystal molecules positioned between the rear alignment film 33b and the front alignment film 33f are aligned in such a manner as to be twisted by about 90 ° from the rear alignment film 33b toward the front alignment film 33 f.

When a voltage is applied to the liquid crystal layer 34 via the rear electrode 32b and the front electrode 32f (driving state), the liquid crystal molecules aligned substantially parallel to the YZ plane are aligned along the X axis. That is, the liquid crystal molecules rise substantially perpendicularly to the rear electrode 32b and the front electrode 32 f.

In a normal state, the liquid crystal optical element 30 rotates the polarization direction of the transmitted polarized light. That is, for example, when the Z-polarized light enters, the Y-polarized light is emitted. In the driven state, the liquid crystal optical element 30 does not rotate the polarization direction of the transmitted polarized light. That is, for example, when the Z-polarized light is incident, the Z-polarized light is still emitted.

As the absorption type polarizer 22, for example, a dye-based polarizer, an iodine-based polarizer, or the like can be used. The absorptive polarizer 22 is arranged such that its absorption axis is along the Y axis and its transmission axis is along the Z axis, for example. In the comparative embodiment, the absorptive polarizer 22 is bonded to the liquid crystal optical element 30 (front substrate 31f) via the adhesive layer 52.

The adhesive layers 51 and 52 are made of an adhesive having light transmittance. The adhesive layers 51, 52 have a thickness of, for example, 5 to 10_μAnd m is about.

Next, the function and operation of the optical device 100 of the comparative method will be described. First, a case where the optical apparatus 100 functions as a display device will be described, and next, a case where the optical apparatus functions as a mirror will be described.

The optical device 100 displays an image on the display surface 11 of the display device 10, and functions as a display device when a voltage is applied to the liquid crystal layer 34 to set the liquid crystal optical element 30 in a driving state.

When the display light Ld emitted from the display device 10 is incident on the reflective polarizer 21, only the Z-polarized light of the display light Ld is transmitted through the reflective polarizer 21. When the Z-polarized light transmitted through the reflective polarizer 21 enters the liquid crystal optical element 30 in a driven state, the polarization direction of the Z-polarized light is not rotated, and the Z-polarized light is directly transmitted through the liquid crystal optical element 30. The Z-polarized light transmitted through the liquid crystal optical element 30 passes through the absorption polarizer 22 and the cover member 40 and reaches the viewer. This allows the observer to recognize the display light Ld emitted from the display device 10, that is, the image displayed on the display surface 11.

On the other hand, the optical device 100 functions as a mirror when the liquid crystal optical element 30 is in a normal state without displaying an image on the display surface 11 of the display device 10 and without applying a voltage to the liquid crystal layer 34.

When the external light Lo transmitted through the cover member 40 enters the absorptive polarizer 22, only the Z-polarized light of the external light Lo transmits through the absorptive polarizer 22. When the Z-polarized light transmitted through the absorption polarizer 22 is incident on the liquid crystal optical element 30 in a normal state, particularly the liquid crystal layer 34 thereof, the Z-polarized light is converted into Y-polarized light and is transmitted through the liquid crystal layer 34.

When the Y polarized light converted by the liquid crystal layer 34 is incident on the reflective polarizer 21, the Y polarized light is reflected by the reflective polarizer 21. When the Y-polarized light reflected by the reflective polarizer 21 is incident on the liquid crystal layer 34, the Y-polarized light is converted into Z-polarized light again. The Z-polarized light converted again by the liquid crystal layer 34 passes through the absorptive polarizer 22 and the cover member 40, and reaches the viewer. This allows the observer to recognize a light reflection image (mirror image) obtained by reflection by the reflective polarizer 21.

The light reflection image obtained by reflection by the reflection type polarizer 21 is preferably free from distortion, defects, and the like. However, when the reflective polarizer 21 is bonded to the liquid crystal optical element 30 via the adhesive layer 51, foreign substances such as dirt and dust may be mixed between the reflective polarizer 21 and the liquid crystal optical element 30 (i.e., between the adhesive layer 51 and the rear substrate 31b), and the foreign substances may be observed as defects in the light reflection image.

Fig. 2 shows a state in which a defect in a light reflection image that occurs when a foreign substance is mixed between the reflective polarizer 21 and the liquid crystal optical element 30 is observed from the liquid crystal optical element 30 side in the comparative method. If foreign matter is mixed between the reflective polarizer 21 and the liquid crystal optical element 30, a portion where the adhesive layer 51 becomes relatively thick or thin, a portion where the reflective polarizer 21 or the liquid crystal optical element 30 is peeled off from the adhesive layer 51 (mixed with air bubbles), or the like is generated around the foreign matter. As a result, a defect having a size 10 times or more the size of the foreign matter may appear in the light reflection image.

In the optical device 100, it is preferable to suppress the occurrence of such defects, and it is preferable to suppress at least the size of the defects to the same extent as the size of the foreign matter so that the defects are inconspicuous. Hereinafter, an optical device in which such a defect of the light reflection image is not conspicuous will be described as an embodiment.

(embodiment 1)

Fig. 3 shows a structure of an optical device 101 according to embodiment 1. The optical device 101 of embodiment 1 has the same configuration and structure as the optical device 100 of the comparative embodiment except for the method of fixing the reflective polarizer 21.

In the optical device 101, the reflective polarizer 21 is bonded to the display surface 11 of the display device 10. The adhesive layer 53 is provided on a surface of the reflective polarizer 21 facing the display device 10, and the reflective polarizer 21 and the display device 10 are bonded by the adhesive layer 53.

In embodiment 1, the polarized light reflected by the reflective polarizer 21 does not pass through the adhesion interface between the reflective polarizer 21 and the display device 10 or the adhesive layer 53 adhering them. Therefore, even when foreign matter is mixed between the reflective polarizer 21 and the display device 10, defects corresponding to the foreign matter, bubbles in the adhesive layer 53 due to the mixing of the foreign matter, and the like do not occur in the light reflection image.

By providing the adhesive layer 53 on the surface of the reflective polarizer 21 facing the display device 10 in this way, the influence of foreign matter that may be mixed into the adhesive layer 53 on the light reflection image can be reduced. This makes it difficult to make a defect of the light reflection image, which is caused by the mixing of the foreign matter, conspicuous, and thus can suppress a reduction in the display quality of the light reflection image.

(embodiment 2)

In embodiment 1, the reflective polarizer 21 is attached to the display device 10. However, the reflection type polarizer 21 may be attached to a separately prepared light transmitting plate. Hereinafter, an optical device in which a reflective polarizer 21 is attached to a light-transmitting plate will be described as embodiment 2.

Fig. 4 shows the structure of the optical device 102 of embodiment 2. The optical device 102 of embodiment 2 has the same configuration and structure as the optical device 101 of embodiment 1, except for the method of fixing the reflective polarizer 21.

In the optical device 102, the reflective polarizer 21 is bonded to the light-transmitting plate 60. The adhesive layer 53 is provided on a surface of the reflective polarizer 21 facing the display device 10, and the reflective polarizer 21 and the light-transmitting plate 60 are bonded together by the adhesive layer 53.

The light-transmitting plate 60 is made of, for example, a translucent glass member. The light-transmitting plate 60 may be any member as long as it has light-transmitting properties and can support the reflective polarizer 21.

The reflective polarizer 21 may be fixed as such. By using the light-transmitting plate 60 having a relatively large thickness, the rigidity (resistance to deformation or flexure) of the entire optical device 102 can be improved.

(embodiment 3)

In embodiment 1 and embodiment 2, a display device 10 using organic EL elements is exemplified as a unit for displaying a desired image. However, as a means for displaying a desired image, a light emitting device including a liquid crystal display element may be used. Hereinafter, an optical device using a light emitting device including a liquid crystal display element will be described as embodiment 3.

Fig. 5 shows the configuration of the optical device 103 of embodiment 3. The optical device 103 of embodiment 3 has the same configuration and structure as the optical device 101 of embodiment 1, except that the display device 10 is replaced with a light exit device 70.

In the optical device 103, the light emitting device 70 is used instead of the display device 10. The light exit device 70 includes: a liquid crystal display element 71 bonded to the reflection type polarizer 21; a light source 72 for irradiating the liquid crystal display element 71 with light; and a polarizing film 73 arranged between the liquid crystal display element 71 and the light source 72.

The liquid crystal display element 71 has an electrode structure of 7-segment type, dot matrix type, or the like, and is driven by a driving method such as VA (Vertical Alignment) or IPS (In Plane Switching). The polarizing film 73 is arranged so as to intersect the reflective polarizer 21, for example, in nicol, and the light emitting device 70 functions as a unit for displaying an image in combination with the reflective polarizer 21.

In this way, instead of the display device 10, the light emitting device 70 functioning as a unit for displaying an image by combining with the reflective polarizer 21 may be used.

(modification example)

Fig. 6 shows an optical device 104 according to a modification of embodiment 1. Note that this modification can be applied to embodiment 2 and embodiment 3.

In embodiment 1, the reflective polarizer 21 is attached to the display device 10. In this case, an optical film 81 such as a viewing angle compensation film or an antiglare film may be attached to the liquid crystal optical element 30.

Usually, such an optical film 81 is laminated on the reflective polarizer 21 and attached to the liquid crystal optical element 30. The optical film 81 and the reflective polarizer 21 generally have flexibility or flexibility, and when they are laminated on the liquid crystal optical element 30, the flatness of the reflective polarizer 21 is impaired, and a light reflection image obtained by reflection by the reflective polarizer 21 may be deformed.

By attaching the optical film 81 and the reflective polarizer 21 to different members, the flatness of the reflective polarizer 21 can be maintained, and the distortion of the light reflection image obtained by the reflection of the reflective polarizer 21 can be prevented. In addition, as a method of attaching the optical film, it is easier to attach the optical film 81 and the reflective polarizer 21 to different members than to attach the optical film 81 and the reflective polarizer 21 to the same member in a superposed manner.

In embodiment 1, the absorptive polarizer 22 is attached to the liquid crystal optical element 30. However, the absorptive polarizer 22 may be attached to the cover member 40 instead of the liquid crystal optical element 30.

In this case, an optical film 82 such as a viewing angle compensation film or an antiglare film may be attached to the liquid crystal optical element 30. As described above, as a method of attaching the optical film, it is easier to attach the optical film 82 and the absorptive polarizer 22 to different members than to attach the optical film 82 and the absorptive polarizer 22 to the same member in a manner of overlapping them. The absorptive polarizer 22 may be attached to the liquid crystal optical element 30, and the optical film 82 may be attached to the cover member 40.

The present invention has been described above with reference to the embodiments and modifications thereof, but the present disclosure is not limited thereto. Various modifications, improvements, combinations, and the like will occur to those skilled in the art.