Optical panel

Abstract

To provide an optical panel with which it is possible to suppress characteristic unevenness in the state of being installed obliquely with respect to the ground surface.SOLUTION: An optical panel 100 comprises a first translucent substrate 10, a second translucent substrate 30, and a liquid crystal 50 or an electrophoretic medium held between the first translucent substrate 10 and the second translucent substrate 30. The optical panel 100 is installed in such a manner that its front face including a variable region 102 is oblique with respect to the ground surface. When applying a voltage to the liquid crystal 50 or the electrophoretic medium to place the variable region 102 into one of two states, a voltage higher than the voltage applied to the liquid crystal 50 or the electrophoretic medium in an upper region 102A of the variable region 102 that is located vertically upward is applied to the liquid crystal 50 or the electrophoretic medium in at least a section of a lower region 102B of the variable region 102 that is located vertically downward.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to an optical panel.

Background Art

[0002] Display panels, spatial light modulators, light control elements, etc. using liquid crystals or electrophoretic media (a light-transmissive dispersion medium and electrophoretic particles) are known. In these optical panels, the liquid crystal or electrophoretic medium is sandwiched between light-transmissive substrates.

[0003] For example, when a liquid crystal display panel is installed perpendicular to the ground, the liquid crystal is biased downward vertically inside the liquid crystal display panel by gravity, and the cell thickness on the vertically lower side of the liquid crystal display panel becomes thicker than the cell thickness on the vertically upper side of the liquid crystal display panel. When the cell thickness of the liquid crystal display panel becomes non-uniform, display unevenness occurs in the liquid crystal display panel.

[0004] Therefore, in Patent Document 1, by changing the elastic modulus per unit area of the spacer that maintains the cell thickness within the plane of the light-transmissive substrate (color filter substrate or array substrate), the non-uniformity of the cell thickness is suppressed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In Patent Document 1, since the elastic modulus per unit area of the spacer is changed within the plane of the light-transmissive substrate, the manufacturing process of the liquid crystal display panel becomes complicated. Also, in elements with a thick cell thickness, such as liquid crystal lens elements and light control elements using electrophoretic media, it is difficult to improve the uniformity of the cell thickness by improving the element structure.

[0007] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide an optical panel capable of suppressing unevenness in characteristics in a state where it is installed inclined with respect to the ground.

Means for Solving the Problems

[0008] The optical panel according to the first aspect is a first light-transmissive substrate, a second light-transmissive substrate facing the first light-transmissive substrate, and an electrophoretic medium including liquid crystal or a light-transmissive dispersion medium and electrophoretic particles, sandwiched between the first light-transmissive substrate and the second light-transmissive substrate. The front surface including a variable region in which the optical characteristics change to two states over the entire surface is installed inclined with respect to the ground. In the installed state, the variable region is bisected into an upper region located vertically above and a lower region located vertically below. When a voltage is applied to the liquid crystal or the electrophoretic medium to set the variable region to one of the two states, a voltage higher than the voltage applied to the liquid crystal or the electrophoretic medium in the upper region is applied to at least a part of the liquid crystal or the electrophoretic medium in the lower region.

[0009] The optical panel according to the second aspect is an electrophoretic medium including a light-transmissive dispersion medium and electrophoretic particles, a first light-transmissive substrate and a second light-transmissive substrate sandwiching the electrophoretic medium, and a plurality of electrodes for applying a voltage to the electrophoretic medium. The front surface including a variable region in which the optical characteristics change to two states over the entire surface is installed inclined with respect to the ground. In the installed state, the variable region is bisected into an upper region located vertically above and a lower region located vertically below. The arrangement pitch of the electrodes arranged in at least a part of the lower region is narrower than the arrangement pitch of the electrodes arranged in the upper region.

Advantages of the Invention

[0010] Since a voltage higher than the voltage applied to the liquid crystal or electrophoretic medium in the upper region located vertically above is applied to at least a part of the lower region located vertically below in the liquid crystal or electrophoretic medium, unevenness in characteristics can be suppressed in a state where it is installed inclined with respect to the ground. Further, since the arrangement pitch of the electrodes arranged in at least a part of the lower region located vertically below is narrower than the arrangement pitch of the electrodes arranged in the upper region located vertically above, unevenness in characteristics can be suppressed in a state where it is installed inclined with respect to the ground.

Brief Description of the Drawings

[0011]

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Mode for Carrying Out the Invention

[0012] Hereinafter, the optical panel according to the embodiment will be described with reference to the drawings.

[0013] <Embodiment 1> With reference to FIGS. 1 to 10, the optical panel 100 according to this embodiment will be described. The optical panel 100 functions as a liquid crystal lens (liquid crystal light deflection element). For example, as shown in FIG. 1, the optical panel 100 is disposed on the display surface side of the liquid crystal display panel 200, and together with the liquid crystal display panel 200, constitutes a display device 300 that displays a planar image and a stereoscopic image. Note that the display light of the liquid crystal display panel 200 is linearly polarized light with a polarization direction in the Y direction.

[0014] The optical panel 100 (display device 300) has its front surface 101 installed perpendicular to the ground. In this embodiment, for ease of understanding, the vertical direction is defined as the Y-axis direction, the direction parallel to the ground and the front surface 101 of the optical panel 100 is defined as the X-axis direction, and the front direction perpendicular to both the X-axis direction and the Y-axis direction is defined as the Z-axis direction for explanation. Also, since the +Y direction becomes upward when the optical panel 100 is installed, the +Y direction is also described as upward or vertically upward, and the -Y direction is described as downward or vertically downward. These definitions are the same in other embodiments.

[0015] The optical panel 100 has a variable region 102 with a changing refractive index distribution and a peripheral region 104 surrounding the variable region 102. The variable region 102 is bisected into an upper region 102A located vertically above and a lower region 102B located vertically below in the installed state. The variable region 102 changes between a state where the refractive index distribution is uniform over the entire surface and a state where the refractive index distribution changes in a predetermined period along the X-axis direction. In this embodiment, the state where the refractive index distribution is uniform over the entire surface is described as the first state, and the state where the refractive index distribution changes in a predetermined period along the X-axis direction is described as the second state.

[0016] When the variable region 102 of the optical panel 100 is in the first state, the display device 300 displays a planar image. When the variable region 102 of the optical panel 100 is in the second state, the optical panel 100 functions as a lenticular lens array in which cylindrical lenses extending in the Y-axis direction are arranged in the X-axis direction, and the display device 300 displays a stereoscopic image.

[0017] The specific configuration of the optical panel 100 will be described. As shown in FIG. 2, the optical panel 100 includes a first light-transmissive substrate 10, a second light-transmissive substrate 30, and liquid crystal 50. The first light-transmissive substrate 10 and the second light-transmissive substrate 30 sandwich the liquid crystal 50.

[0018] The first light-transmissive substrate 10 transmits visible light. The first light-transmissive substrate 10 is, for example, a flat glass substrate. As shown in FIG. 2, the first light-transmissive substrate 10 has a plurality of drive electrodes 12 and an alignment film 14.

[0019] As shown in FIGS. 2 and 3, the drive electrode 12 is provided on the main surface 10a on the liquid crystal 50 side of the first light-transmissive substrate 10. The drive electrode 12 has a rectangular shape and extends along the Y-axis direction, and is disposed in the variable region 102 at a predetermined interval in the X-axis direction. The drive electrode 12 is bisected into a first drive electrode 12A and a second drive electrode 12B.

[0020] The first drive electrode 12A has a rectangular shape and extends along the Y-axis direction, and is located in the upper region 102A of the variable region 102. The second drive electrode 12B has a rectangular shape and extends along the Y-axis direction, and is located in the lower region 102B of the variable region 102. The first drive electrode 12A and the second drive electrode 12B are arranged side by side along the Y-axis direction. Each of the first drive electrode 12A and the second drive electrode 12B is connected to the control unit 310 via a wiring (not shown). The drive electrode 12 (the first drive electrode 12A and the second drive electrode 12B) is formed of a conductive film that transmits visible light. The drive electrode 12 is formed of, for example, ITO (Indium Tin Oxide).

[0021] The alignment film 14 is provided on the main surface 10a, the first drive electrode 12A, and the second drive electrode 12B. The alignment film 14 aligns the liquid crystal 50 in the Y-axis direction. The alignment film 14 is, for example, an alignment-treated polyimide alignment film.

[0022] The second light-transmissive substrate 30 transmits visible light. The second light-transmissive substrate 30 is, for example, a flat glass substrate. As shown in FIG. 2, the second light-transmissive substrate 30 faces the first light-transmissive substrate 10 and is bonded to the first light-transmissive substrate 10 by a sealing material 70. The second light-transmissive substrate 30 has a common electrode 32 and an alignment film 34.

[0023] The common electrode 32 is provided on the main surface 30a on the liquid crystal 50 side of the second light-transmissive substrate 30. As shown in FIGS. 2 and 4, the common electrode 32 is formed in a rectangular shape and faces the first drive electrode 12A and the second drive electrode 12B. The common electrode 32 is connected to the control unit 310 via a wiring (not shown). The common electrode 32 is formed of a conductive film that transmits visible light. The common electrode 32 is formed of, for example, ITO.

[0024] The alignment film 34 is provided on the common electrode 32. The alignment film 34 aligns the liquid crystal 50 in the Y-axis direction. The alignment film 34 is, for example, an alignment-treated polyimide alignment film.

[0025] The liquid crystal 50 is sandwiched between the first light-transmissive substrate 10 and the second light-transmissive substrate 30. The liquid crystal 50 is, for example, a positive nematic liquid crystal. The liquid crystal 50 is aligned in the Y-axis direction by the alignment films 14 and 34.

[0026] Here, the operation of the optical panel 100 will be described. The optical panel 100 functions as a lenticular lens array due to the change in the alignment of the liquid crystal 50.

[0027] For example, when the control unit 310 sets the potentials of the drive electrodes 12 (the first drive electrodes 12A and the second drive electrodes 12B) of the first light-transmissive substrate 10 and the potential of the common electrode 32 of the second light-transmissive substrate 30 to the same potential (for example, the ground potential), no voltage is applied to the liquid crystal 50, so the liquid crystal 50 maintains its alignment in the Y-axis direction. In this case, the variable region 102 has a uniform refractive index distribution over the entire surface (that is, the first state), and the optical panel 100 does not function as a lenticular lens array.

[0028] On the other hand, when the potential of the common electrode 32 is set to the ground potential and the potentials of the drive electrodes 12a to 12e arranged in the X-axis direction are increased in the order of drive electrode 12a, 12e > drive electrode 12b, 12d > drive electrode 12c, as shown in FIG. 5, the rising of the liquid crystal molecules M with respect to the main surface 10a of the first light-transmissive substrate 10 increases from the drive electrode 12c toward the drive electrode 12a or the drive electrode 12e. In this case, the variable region 102 has a state in which the refractive index distribution changes in a predetermined period along the X-axis direction (that is, the second state), and the optical panel 100 functions as a lenticular lens array extending in the Y-axis direction and arranged in the X-axis direction.

[0029] The optical panel 100 has a front surface 101 including a variable region 102, and is installed perpendicular to the ground. As a result, as shown in FIG. 6, the liquid crystal 50 is biased by gravity to the lower region 102B of the variable region 102, and the thickness (cell thickness) D2 of the liquid crystal 50 in the lower region 102B of the optical panel 100 becomes greater than the thickness D1 of the liquid crystal 50 in the upper region 102A of the optical panel 100. When the thickness D2 of the liquid crystal 50 in the lower region 102B is greater than the thickness D1 of the liquid crystal 50 in the upper region 102A, if the same voltage is applied to the liquid crystal 50 in the lower region 102B and the liquid crystal 50 in the upper region 102A, a difference occurs in the focal length (retardation) of the lenticular lens in the upper region 102A and the lower region 102B. Due to the difference between the focal length of the upper region 102A and the focal length of the lower region 102B, the image quality of the stereoscopic image displayed by the display device 300 deteriorates.

[0030] Note that in FIG. 6, for ease of understanding, the alignment films 14 and 34 are omitted, and the hatching of each part is also omitted. In the following figures, the alignment films 14, the alignment film 34, etc. may be omitted, and the hatching of each part may also be omitted.

[0031] Therefore, in the present embodiment, a voltage higher than the voltage applied to the liquid crystal 50 in the upper region 102A is applied to the liquid crystal 50 in the lower region 102B by the common electrode 32 and the second drive electrode 12B. Thereby, unevenness in optical characteristics (that is, unevenness in focal length, unevenness in retardation, etc.) between the upper region 102A and the lower region 102B can be suppressed.

[0032] Hereinafter, taking the case of forming one lenticular lens (lens pitch: 147 μm) with 13 driving electrodes 12 (first driving electrode 12A or second driving electrode 12B) arranged in the X direction, with the refractive index anisotropy Δn of the liquid crystal 50 being 0.2556, the thickness D1 of the liquid crystal 50 in the upper region 102A being 50 μm, and the thickness D2 of the liquid crystal 50 in the lower region 102B being 55 μm as an example, the distribution of retardation R in the upper region 102A and the lower region 102B will be described. The distribution of retardation R is formed by applying a voltage to the liquid crystal 50 to generate a distribution of the refractive index anisotropy Δn with respect to the incident light (display light of the liquid crystal display panel 200). In the present embodiment, as described above, the rising of the liquid crystal molecules M changes along the X-axis direction due to the application of the voltage, and as a result, a distribution of the refractive index anisotropy Δn with respect to the incident light occurs.

[0033] With the potential of the common electrode 32 being the ground potential, and the potentials of the first to thirteenth first driving electrodes 12A or second driving electrodes 12B being controlled to the potentials as shown in FIG. 7 in order from the -X direction, when the same voltage is applied to the liquid crystal 50 in the lower region 102B and the liquid crystal 50 in the upper region 102A (comparative example), as shown in FIG. 8, a difference (non-uniformity) in retardation R occurs between the upper region 102A and the lower region 102B.

[0034] In the present embodiment, as shown in FIG. 9, the potential of the second driving electrode 12B is controlled to be higher than the potential of the first driving electrode 12A, and a voltage higher than the voltage applied to the liquid crystal 50 in the upper region 102A is applied to the liquid crystal 50 in the lower region 102B. In this case, as shown in FIG. 10, the retardation R in the lower region 102B can be made to match the retardation R in the upper region 102A.

[0035] As described above, by applying a voltage higher than the voltage applied to the liquid crystal 50 in the upper region 102A to the liquid crystal 50 in the lower region 102B, the non-uniformity in the optical characteristics between the upper region 102A and the lower region 102B can be suppressed.

[0036] <Embodiment 2> In Embodiment 1, a voltage higher than the voltage applied to the liquid crystal 50 in the upper region 102A is applied to the liquid crystal 50 in the lower region 102B. In the optical panel 100, a voltage higher than the voltage applied to the liquid crystal 50 in the upper region 102A may be applied to the liquid crystal 50 in a partial region of the lower region 102B.

[0037] Similar to the optical panel 100 of Embodiment 1, the optical panel 100 of the present embodiment is installed with the front surface 101 perpendicular to the ground. Also, similar to the optical panel 100 of Embodiment 1, the optical panel 100 of the present embodiment has a variable region 102 and a peripheral region 104, and includes a first light-transmissive substrate 10, a second light-transmissive substrate 30, and a liquid crystal 50. Since the operation of the optical panel 100 of the present embodiment and the configurations of the second light-transmissive substrate 30 and the liquid crystal 50 are the same as those of Embodiment 1, the first light-transmissive substrate 10 and the region to which a voltage higher than the voltage applied to the liquid crystal 50 in the upper region 102A is applied will be described.

[0038] Similar to the first light-transmissive substrate 10 of Embodiment 1, the first light-transmissive substrate 10 of the present embodiment has a plurality of drive electrodes 12 and an alignment film 14. The configuration of the alignment film 14 is the same as that of Embodiment 1.

[0039] Similar to the drive electrode 12 of Embodiment 1, the drive electrode 12 of the present embodiment is provided on the main surface 10a of the first light-transmissive substrate 10. Also, the drive electrode 12 of the present embodiment has a rectangular shape, extends along the Y-axis direction, and is arranged at a predetermined interval in the X-axis direction. The drive electrode 12 of the present embodiment is divided into two, a first drive electrode 12A and a second drive electrode 12B.

[0040] As shown in FIGS. 11 and 12, the first drive electrode 12A of the present embodiment extends along the Y-axis direction and is arranged in a 2 / 3 region 102C located vertically above in the variable region 102 including the upper region 102A. Also, the second drive electrode 12B of the present embodiment extends along the Y-axis direction and is arranged in a 1 / 3 region 102D located vertically below in the variable region 102. The region 102D corresponds to a 2 / 3 region located vertically below in the lower region 102B.

[0041] When the optical panel 100 is installed with the front surface 101 perpendicular to the ground, depending on the materials of the first light-transmissive substrate 10 and the second light-transmissive substrate 30, the thickness of the liquid crystal 50, etc., the thickness of the liquid crystal 50 in the narrow region vertically below in the lower region 102B may become thicker. Therefore, in the present embodiment, a voltage higher than the voltage applied to the liquid crystal 50 in the region 102C by the common electrode 32 and the first drive electrode 12A is applied to the liquid crystal 50 in the region 102D by the common electrode 32 and the second drive electrode 12B. Thereby, similar to the upper region 102A and the lower region 102B of the first embodiment, unevenness in the optical characteristics (unevenness in retardation R) between the region 102C and the region 102D can be suppressed.

[0042] <Embodiment 3> In the first embodiment and the second embodiment, the first light-transmissive substrate 10 and the second light-transmissive substrate 30 sandwich the liquid crystal 50. The first light-transmissive substrate 10 and the second light-transmissive substrate 30 may sandwich an electrophoretic medium.

[0043] The optical panel 100 of the present embodiment is installed with the front surface 101 perpendicular to the ground in the same manner as the optical panel 100 of the first embodiment. Further, the optical panel 100 of the present embodiment has a variable region 102 and a peripheral region 104 and includes a first light-transmissive substrate 10 and a second light-transmissive substrate 30 in the same manner as the optical panel 100 of the first embodiment. The optical panel 100 of the present embodiment includes an electrophoretic medium 80 containing a light-transmissive dispersion medium 82 and electrophoretic particles 84 instead of the liquid crystal 50.

[0044] In the present embodiment, the variable region 102 changes between a state of blocking light over the entire surface and a state in which regions blocking light and regions transmitting light occur over the entire surface. That is, the optical panel 100 of the present embodiment functions as a light control element. In the present embodiment, the state of blocking light over the entire surface is referred to as the first state, and the state in which regions blocking light and regions transmitting light occur over the entire surface is referred to as the second state.

[0045] The first light-transmissive substrate 10 of the present embodiment transmits visible light, similar to the first light-transmissive substrate 10 of Embodiments 1 and 2. As shown in FIG. 13, the first light-transmissive substrate 10 of the present embodiment has a plurality of drive electrodes 12 and an insulating layer 16.

[0046] The drive electrode 12 of the present embodiment has a rectangular shape and extends along the Y-axis direction, similar to the drive electrode 12 of Embodiment 2. Further, the drive electrode 12 of the present embodiment is arranged in the variable region 102 at a predetermined interval in the X-axis direction. Furthermore, similar to Embodiment 2, the drive electrode 12 is divided into two, a first drive electrode 12A and a second drive electrode 12B. The first drive electrode 12A is arranged in the region 102C, and the second drive electrode 12B is arranged in the region 102D (FIG. 11). Also in the present embodiment, each of the first drive electrode 12A and the second drive electrode 12B is connected to the control unit 310 via wiring (not shown). The drive electrode 12 of the present embodiment is formed of a metal such as aluminum (Al) or molybdenum (Mo).

[0047] The insulating layer 16 is provided on the main surface 10a, the first drive electrode 12A, and the second drive electrode 12B. The insulating layer 16 is formed of, for example, silicon oxide (SiO2).

[0048] The second light-transmissive substrate 30 of the present embodiment transmits visible light, similar to the second light-transmissive substrate 30 of Embodiments 1 and 2. The second light-transmissive substrate 30 faces the first light-transmissive substrate 10 and is bonded to the first light-transmissive substrate 10 by a sealing material 70. The second light-transmissive substrate 30 and the first light-transmissive substrate 10 sandwich the electrophoretic medium 80. As shown in FIG. 13, the second light-transmissive substrate 30 of the present embodiment has a plurality of counter electrodes 33 and an insulating layer 36.

[0049] As shown in FIGS. 13 and 14, the counter electrode 33 has a rectangular shape and extends in the Y-axis direction. In the present embodiment, one counter electrode 33 faces one drive electrode 12 (the first drive electrode 12A and the second drive electrode 12B divided from one drive electrode 12). The counter electrode 33 is formed of a metal such as aluminum (Al) or molybdenum (Mo) and is connected to the control unit 310.

[0050] The insulating layer 36 is provided on the main surface 30a of the second translucent substrate 30 and on the counter electrode 33. The insulating layer 36 is formed of, for example, silicon oxide (SiO2).

[0051] The electrophoretic medium 80 is sandwiched between the first translucent substrate 10 and the second translucent substrate 30. The electrophoretic medium 80 includes a translucent dispersion medium 82 and electrophoretic particles 84.

[0052] The translucent dispersion medium 82 transmits visible light. The translucent dispersion medium 82 disperses the electrophoretic particles 84.

[0053] The electrophoretic particles 84 are dispersed in the translucent dispersion medium 82 and absorb visible light. The electrophoretic particles 84 are charged positively or negatively, and the dispersion state in the translucent dispersion medium 82 changes due to the voltage applied by the first drive electrode 12A or the second drive electrode 12B and the counter electrode 33. The electrophoretic particles 84 are, for example, charged carbon black particles. In the present embodiment, it is assumed that the electrophoretic particles 84 are negatively charged.

[0054] Here, the operation of the optical panel 100 of the present embodiment will be described. The optical panel 100 of the present embodiment functions as a light control element due to the change in the dispersion state of the electrophoretic particles 84.

[0055] For example, when the control unit 310 makes the potentials of the drive electrodes 12 (the first drive electrode 12A and the second drive electrode 12B) of the first translucent substrate 10 and the potential of the counter electrode 33 of the second translucent substrate 30 the same potential, the electrophoretic particles 84 that absorb visible light are uniformly dispersed over the entire variable region 102. Therefore, the variable region 102 of the optical panel 100 of the present embodiment absorbs visible light and becomes a state of shielding visible light over the entire surface (that is, the first state).

[0056] On one hand, when the potential of the driving electrodes 12 (the first driving electrode 12A and the second driving electrode 12B) of the first light-transmissive substrate 10 is made higher than the potential of the counter electrode 33 of the second light-transmissive substrate 30, as shown in FIG. 15, the electrophoretic particles 84 gather at the driving electrodes 12 (the first driving electrode 12A or the second driving electrode 12B). As a result, a region 112 that shields visible light and a region 114 that transmits visible light, where the electrophoretic particles 84 have gathered at the driving electrodes 12, are formed. Therefore, the variable region 102 of the optical panel 100 of the present embodiment is in a state (i.e., the second state) where the region 112 that shields visible light and the region 114 that transmits visible light are formed over the entire surface.

[0057] The front surface 101 including the variable region 102 of the optical panel 100 of the present embodiment is also installed perpendicular to the ground. As a result, the electrophoretic medium 80 (the light-transmissive dispersion medium 82 and the electrophoretic particles 84) biases toward the vertically lower region (region 102D in the present embodiment) of the variable region 102, and the thickness (cell thickness) D2 of the electrophoretic medium 80 in the vertically lower region (region 102D) becomes thicker than the thickness D1 of the electrophoretic medium 80 in the upper region 102A.

[0058] The moving speed v of the electrophoretic particles 84 is expressed by the following formula (1), where the mobility is μ, the electric field strength (voltage per unit distance) is E, the effective charge is Q, the radius of the electrophoretic particles 84 is r, the viscosity of the light-transmissive dispersion medium 82 is η, the applied voltage is V, and the distance between the driving electrode 12 and the counter electrode 33 is L.

[0059]

Equation

[0060] When the thickness (cell thickness) of the electrophoresis medium 80 increases, the distance L between the drive electrode 12 and the counter electrode 33 becomes longer, and from Equation (1), the moving speed v of the electrophoresis particles 84 becomes slower. Therefore, when the same voltage is applied to the electrophoresis medium 80 in region 102C and the electrophoresis medium 80 in region 102D, the movement of the electrophoresis particles 84 in region 102D becomes slower than the movement of the electrophoresis particles 84 in region 102C. As a result, a difference occurs in the response time for transitioning from the first state to the second state between region 102C and region 102D.

[0061] In the present embodiment, a voltage higher than the voltage applied to the electrophoresis medium 80 in region 102C by the counter electrode 33 and the first drive electrode 12A is applied to the electrophoresis medium 80 in region 102D by the counter electrode 33 and the second drive electrode 12B. Thereby, the difference in response time (non-uniformity of response characteristics) between region 102C and region 102D can be suppressed. In one example, when the thickness D1 of region 102C (upper region 102A) is 25 μm and the thickness D2 of region 102D is 30 μm, by applying 24.0 V to the electrophoresis medium 80 in region 102C and 28.8 V to the electrophoresis medium 80 in region 102D, the difference in response time between region 102C and region 102D can be suppressed.

[0062] <Embodiment 4> In Embodiment 3, the drive electrode 12 (the first drive electrode 12A and the second drive electrode 12B) and the counter electrode 33 are arranged in the X-axis direction with the same array pitch, and a voltage is applied to the electrophoresis medium 80. The array pitch of the drive electrode 12 and the counter electrode 33 arranged in the X-axis direction in region 102C and the array pitch of the drive electrode 12 and the counter electrode 33 arranged in the X-axis direction in region 102D may be different.

[0063] The optical panel 100 of the present embodiment is installed with the front surface 101 perpendicular to the ground in the same manner as the optical panel 100 of Embodiment 3. Also, the optical panel 100 of the present embodiment has a variable region 102 and a peripheral region 104 and includes a first light-transmissive substrate 10, a second light-transmissive substrate 30, and an electrophoresis medium 80, in the same manner as the optical panel 100 of Embodiment 3. Furthermore, the optical panel 100 of the present embodiment functions as a light control element.

[0064] The configuration of the optical panel 100 of this embodiment is the same as that of the optical panel 100 in Embodiment 3, except that the first translucent substrate 10 has a third driving electrode 18 and a fourth driving electrode 19 instead of the driving electrodes 12 (the first driving electrode 12A and the second driving electrode 12B), and the second translucent substrate 30 has a third counter electrode 38 and a fourth counter electrode 39 instead of the counter electrode 33. Here, the third driving electrode 18 and the fourth driving electrode 19 of the first translucent substrate 10, and the third counter electrode 38 and the fourth counter electrode 39 of the second translucent substrate 30 will be described.

[0065] As shown in FIG. 16, the third driving electrode 18 of the first translucent substrate 10 is provided on the main surface 10a of the first translucent substrate 10. The third driving electrode 18 has a rectangular shape and extends along the Y-axis direction. The third driving electrode 18 is disposed in the region 102C and is arranged in the X-axis direction at a predetermined first arrangement pitch P1.

[0066] Similar to the third driving electrode 18, the fourth driving electrode 19 of the first translucent substrate 10 is provided on the main surface 10a of the first translucent substrate 10 and extends along the Y-axis direction. The fourth driving electrode 19 is disposed in the region 102D. The fourth driving electrode 19 is arranged in the X-axis direction at a predetermined second arrangement pitch P2 that is narrower than the first arrangement pitch P1 of the third driving electrode 18.

[0067] As shown in FIG. 17, the third counter electrode 38 of the second translucent substrate 30 is provided on the main surface 30a of the second translucent substrate 30. The third counter electrode 38 has a rectangular shape and extends along the Y-axis direction. The third counter electrode 38 is arranged in the region 102C in the X-axis direction at the same arrangement pitch as the first arrangement pitch P1 of the third driving electrode 18. Each of the third counter electrodes 38 faces each of the third driving electrodes 18.

[0068] The fourth counter electrode 39 of the second light-transmissive substrate 30 is provided on the main surface 30a of the second light-transmissive substrate 30 and extends along the Y-axis direction, similarly to the third counter electrode 38. The fourth counter electrode 39 is arranged in the X-axis direction with the same arrangement pitch as the second arrangement pitch P2 of the fourth driving electrode 19 in the region 102D. Each of the fourth counter electrodes 39 faces each of the fourth driving electrodes 19.

[0069] In this embodiment, the second arrangement pitch P2 of the fourth driving electrode 19 and the fourth counter electrode 39 arranged in the region 102D is smaller than the first arrangement pitch P1 of the third driving electrode 18 and the third counter electrode 38 arranged in the region 102C. Thereby, even if the voltage applied to the electrophoretic medium 80 by the third driving electrode 18 and the third counter electrode 38 is the same as the voltage applied to the electrophoretic medium 80 by the fourth driving electrode 19 and the fourth counter electrode 39, the intensity of the electric field acting on the thick electrophoretic medium 80 in the region 102D can be made closer to the intensity of the electric field acting on the thin electrophoretic medium 80 in the region 102C, and the difference in response time (non-uniformity of response characteristics) between the region 102C and the region 102D can be suppressed.

[0070] <Modification example> Although the embodiments have been described above, the present disclosure can be variously modified without departing from the gist thereof.

[0071] In Embodiments 1 to 4, the optical panel 100 is installed with the front surface 101 perpendicular to the ground. The optical panel 100 may be installed with the front surface 101 inclined with respect to the ground.

[0072] In Embodiment 1, a voltage higher than the voltage applied to the liquid crystal 50 in the upper region 102A is applied to the liquid crystal 50 in the lower region 102B. Also, in Embodiment 2 and Embodiment 3, a voltage higher than the voltage applied to the liquid crystal 50 or the electrophoretic medium 80 in the upper region 102A is applied to the liquid crystal 50 or the electrophoretic medium 80 in the region 102D (the lower two-thirds region located vertically below the lower region 102B). In the optical panel 100, a voltage higher than the voltage applied to the liquid crystal 50 or the electrophoretic medium 80 in the upper region 102A may be applied to at least a part of the liquid crystal 50 or the electrophoretic medium 80 in the lower region 102B according to the thickness of the liquid crystal 50 or the electrophoretic medium 80 in the lower region 102B.

[0073] The optical panel 100 of Embodiment 3 may not include the insulating layers 16 and 36.

[0074] In Embodiment 4, the second arrangement pitch P2 of the fourth driving electrode 19 and the fourth counter electrode 39 arranged in the region 102D is narrower than the first arrangement pitch P1 of the third driving electrode 18 and the third counter electrode 38 arranged in the region 102C. In the optical panel 100, the arrangement pitch of the driving electrodes arranged in at least a part of the lower region 102B may be narrower than the arrangement pitch of the driving electrodes arranged in the upper region 102A according to the thickness of the electrophoretic medium 80 in the lower region 102B.

[0075] In Embodiments 1 to 3, the driving electrode 12 is divided into a first driving electrode 12A and a second driving electrode 12B. In the optical panels 100 of Embodiments 1 and 2, the common electrode 32 is divided into two, and the driving electrode 12 may not be divided. For example, as shown in FIG. 18, the first light-transmissive substrate 10 has a driving electrode 12 that is not divided, and the second light-transmissive substrate 30 may have a common electrode 32 divided into a first common electrode 32A located in the upper region 102A and a second common electrode 32B located in the lower region 102B. In this case, as shown in FIG. 19, by setting the potential of the first common electrode 32A to zero and inverting the potential of the second common electrode 32B with respect to the potential of the driving electrode 12, a voltage higher than the voltage applied to the liquid crystal 50 in the upper region 102A may be applied to the liquid crystal 50 in the lower region 102B.

[0076] In Embodiment 3, the counter electrode 33 is divided into two, and the driving electrode 12 does not necessarily have to be divided.

[0077] The driving electrode 12 may be divided into three or more. For example, as shown in FIG. 20, the driving electrode 12 is divided into four, and the first driving electrode 12A is disposed in the upper region 102A of the first light-transmissive substrate 10, and the driving electrodes 12C to 12E may be disposed in the lower region 102B of the first light-transmissive substrate 10. In this case, voltages higher than the voltage applied to the liquid crystal 50 or the electrophoretic medium 80 in the upper region 102A and different from each other may be applied to the liquid crystal 50 or the electrophoretic medium 80 in the region corresponding to each of the driving electrodes 12C to 12E, according to the thickness of the liquid crystal 50 or the electrophoretic medium 80. Thereby, unevenness in the optical characteristics or unevenness in the response characteristics of the optical panel 100 can be further suppressed.

[0078] Furthermore, the common electrode 32 or the counter electrode 33 may also be divided into three or more. Thereby, unevenness in the optical characteristics or unevenness in the response characteristics of the optical panel 100 can be further suppressed.

[0079] The direction in which the electrodes such as the driving electrode 12 (the first driving electrode 12A, the second driving electrode 12B), the third driving electrode 18, etc. extend is arbitrary. For example, in the optical panel 100 of Embodiment 1, the driving electrode 12 (the first driving electrode 12A, the second driving electrode 12B) may be inclined at an angle θ counterclockwise with respect to the Y-axis direction, as shown in FIG. 21. In this case, the optical panel 100 including the liquid crystal 50 functions as a lenticular lens array inclined at an angle θ with respect to the arrangement direction (Y-axis direction) of the pixels (viewpoint pixels that display a plurality of viewpoint images) 202 of the liquid crystal display panel 200, as shown in FIG. 20. Thereby, the optical panel 100 can distribute the display light not only from the pixels 202 arranged in the X-axis direction but also from the pixels 202 arranged in the Y-axis direction in different directions. In the example shown in FIG. 22, six viewpoint images can be presented. The numbers attached to the pixels 202 in FIG. 22 indicate the numbers of the viewpoint images.

[0080] In Embodiment 1, the display device 300 displays a planar image and a stereoscopic image. The display device 300 may be a multi-screen display device that presents different images to observers located at different positions by means of a lenticular lens array.

[0081] As described above, the preferred embodiments have been explained. However, the present disclosure is not limited to such specific embodiments, and the present disclosure includes the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0082] 10 First light-transmissive substrate, 10a Main surface, 12, 12a to 12e Driving electrodes, 12A First driving electrode, 12B Second driving electrode, 12C to 12E Driving electrodes, 14 Alignment film, 16 Insulating layer, 18 Third driving electrode, 19 Fourth driving electrode, 30 Second light-transmissive substrate, 30a Main surface, 32 Common electrode, 33 Counter electrode, 34 Alignment film, 36 Insulating layer, 38 Third counter electrode, 39 Fourth counter electrode, 50 Liquid crystal, 70 Sealing material, 80 Electrophoretic medium, 82 Light-transmissive dispersion medium, 84 Electrophoretic element, 100 Optical panel, 102 Variable region, 102A Upper region, 102B Lower region, 102C, 102D Regions, 104 Peripheral region, 112 Region that shields light, 114 Region that transmits light, 200 Liquid crystal display panel, 202 Pixel, 300 Display device, 310 Control unit, Δn Refractive index anisotropy, θ Angle, D1, D2 Thickness, P1 First array pitch, P2 Second array pitch, R Retardation, M Liquid crystal molecules

Claims

1. a first light-transmissive substrate; a second light-transmissive substrate facing the first light-transmissive substrate; a liquid crystal or an electrophoretic medium including a light-transmissive dispersion medium and electrophoretic particles, sandwiched between the first light-transmissive substrate and the second light-transmissive substrate; a front surface including a variable region whose optical characteristics change between two states over the entire surface is installed inclined with respect to the ground; in the installed state, the variable region is bisected into an upper region located vertically above and a lower region located vertically below; when a voltage is applied to the liquid crystal or the electrophoretic medium to set the variable region to one of the two states; a voltage higher than the voltage applied to the liquid crystal or the electrophoretic medium in the upper region is applied to at least a part of the liquid crystal or the electrophoretic medium in the lower region; an optical panel.

2. when a voltage is applied to the liquid crystal or the electrophoretic medium to set the variable region to one of the two states; a voltage higher than the voltage applied to the liquid crystal or the electrophoretic medium in the upper region is applied to the liquid crystal or the electrophoretic medium in two-thirds of the region located vertically below in the lower region; The optical panel according to claim 1.

3. the electrophoretic medium is sandwiched between the first light-transmissive substrate and the second light-transmissive substrate; in one state of the variable region, light is transmitted; in the other state of the two states of the variable region, light is blocked; The optical panel according to claim 1 or 2.

4. the liquid crystal is sandwiched between the first light-transmissive substrate and the second light-transmissive substrate; in one state of the variable region, the refractive index distribution by the liquid crystal changes at a predetermined period along a direction parallel to the ground; The optical panel according to claim 1 or 2.

5. having a driving electrode and a common electrode for applying a voltage to the liquid crystal or the electrophoretic medium; the driving electrode or the common electrode is divided according to the position of the region to which a voltage higher than the voltage applied to the liquid crystal or the electrophoretic medium in the upper region is applied to the liquid crystal or the electrophoretic medium; The optical panel according to claim 1 or 2.

6. an electrophoretic medium including a light-transmissive dispersion medium and electrophoretic particles; a first light-transmissive substrate and a second light-transmissive substrate sandwiching the electrophoretic medium; a plurality of electrodes for applying a voltage to the electrophoretic medium. The front surface including a variable region whose optical properties change between two states over the entire surface is installed inclined with respect to the ground. In the installed state, the variable region is bisected into an upper region located vertically above and a lower region located vertically below. The arrangement pitch of the electrodes arranged in at least a part of the lower region is narrower than the arrangement pitch of the electrodes arranged in the upper region. Optical panel. Claim 7 The arrangement pitch of the electrodes arranged in the 2 / 3 region located on the vertically lower side of the lower region is narrower than the arrangement pitch of the electrodes arranged in the upper region. The optical panel according to claim 6. Claim 8 In one of the two states of the variable region, light is transmitted. In the other of the two states of the variable region, light is blocked. The optical panel according to claim 6 or 7.

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