Optical panel

Abstract

An optical panel includes a first light-transmissive substrate, a second light-transmissive substrate, and a liquid crystal or electrophoretic medium sandwiched between the first and second light-transmissive substrates. The optical panel is mounted with a front surface including a variable region inclined with respect to the ground. When a voltage is applied to the liquid crystal or the electrophoretic medium to set the variable region to one of the two states, the voltage is applied to the liquid crystal or the electrophoretic medium located in at least a partial region of a vertically downward lower region in the variable region, the voltage is higher than a voltage applied to the liquid crystal or the electrophoretic medium in a vertically upward upper region in the variable region.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to Japanese Patent Application No. 2023 - 222810, filed on December 28, 2023, the entire disclosure of which is incorporated herein by reference. Technical field

[0003] The present invention generally relates to an optical panel. Background art

[0004] Display panels, spatial modulation elements, light control elements, etc. using liquid crystals or electrophoretic media (light - transmissive dispersion media and electrophoretic particles) are known in the related art. In these optical panels, the liquid crystal or electrophoretic medium is sandwiched between light - transmissive substrates.

[0005] For example, when a liquid crystal display panel is mounted perpendicular to the ground, due to gravity, the liquid crystal is biased to the vertically downward side in the liquid crystal display panel, and the cell thickness on the vertically downward side of the liquid crystal display panel is greater than the cell thickness on the vertically upward side of the liquid crystal display panel. When the cell thickness of the liquid crystal display panel is uneven, display non - uniformity occurs in the liquid crystal display panel.

[0006] To solve this problem, in Japanese Patent Application Laid - Open No. 2005 - 215113, by changing the elastic modulus per unit area of the spacers that hold the cell thickness within the plane of the light - transmissive substrate (color filter substrate or array substrate), the unevenness of the cell thickness is suppressed.

[0007] In Japanese Patent Application Laid - Open No. 2005 - 215113, the elastic modulus per unit area of the spacers varies within the plane of the light - transmissive substrate, and this complicates the manufacturing process of the liquid crystal display panel. In addition, for elements with a large 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.

[0008] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide an optical panel that can suppress non - uniformity of characteristics when the optical panel is mounted inclined with respect to the ground. Summary of the invention

[0009] The optical panel according to the first aspect includes:

[0010] A first light - transmissive substrate;

[0011] A second light - transmissive substrate facing the first light - transmissive substrate; and

[0012] A liquid crystal or an electrophoretic medium including a light - transmissive dispersion medium and electrophoretic particles, the liquid crystal or electrophoretic medium being sandwiched between the first light - transmissive substrate and the second light - transmissive substrate, wherein

[0013] The front surface including the variable region is installed inclined with respect to the ground, in which the optical properties vary between two states over the entire surface.

[0014] In the installed state, the variable region is bisected into an upper region placed vertically upward and a lower region placed vertically downward, and

[0015] In the case of applying a voltage to the liquid crystal or electrophoretic medium to set the variable region to one of the two states,

[0016] A voltage higher than the voltage applied to the liquid crystal or electrophoretic medium in the upper region is applied to the liquid crystal or electrophoretic medium in at least a part of the lower region.

[0017] The optical panel according to the second aspect includes:

[0018] An electrophoretic medium including a light-transmitting dispersion medium and electrophoretic particles;

[0019] A first light-transmitting substrate and a second light-transmitting substrate sandwiching the electrophoretic medium; and,

[0020] A plurality of electrodes applying a voltage to the electrophoretic medium, wherein

[0021] The front surface including the variable region is installed inclined with respect to the ground, in which the optical properties vary between two states over the entire surface.

[0022] In the installed state, the variable region is bisected into an upper region placed vertically upward and a lower region placed vertically downward, and

[0023] The arrangement pitch of the electrodes provided in at least a part of the lower region is narrower than the arrangement pitch of the electrodes provided in the upper region.

[0024] It should be understood that the above general description and the following detailed description are both exemplary and explanatory, and not restrictive of the present disclosure.

[0025] A voltage is applied to the liquid crystal or electrophoretic medium in at least a part of the lower region placed vertically downward, and this voltage is higher than the voltage applied to the liquid crystal or electrophoretic medium in the upper region placed vertically upward. Therefore, when the optical panel is installed inclined with respect to the ground, the inconsistency of the characteristics can be suppressed. In addition, the arrangement pitch of the electrodes provided in at least a part of the lower region placed vertically downward is narrower than the arrangement pitch of the electrodes provided in the upper region placed vertically upward. Therefore, when the optical panel is installed inclined with respect to the ground, the inconsistency of the characteristics can be suppressed. Description of the Drawings

[0026] The present application can be more comprehensively understood when considering the following detailed description in conjunction with the following drawings, in which:

[0027] Figure 1 is a schematic diagram showing an optical panel, a liquid crystal display panel, and a display device according to Embodiment 1;

[0028] Figure 2 is Figure 1 a cross-sectional view taken along line A-A of the shown optical panel;

[0029] Figure 3 is a plan view showing a first driving electrode and a second driving electrode according to Embodiment 1;

[0030] Figure 4 is a plan view showing a common electrode according to Embodiment 1;

[0031] Figure 5 is a schematic diagram showing the alignment of liquid crystal molecules in a second state according to Embodiment 1;

[0032] Figure 6 is a schematic diagram showing a cross-section of the optical panel in an installed state according to Embodiment 1;

[0033] Figure 7 is a graph showing the potential of a first driving electrode or a second driving electrode according to a comparative example;

[0034] Figure 8 is a graph showing the retardation distribution in an upper region and a lower region according to a comparative example;

[0035] Figure 9 is a graph showing the potential of a first driving electrode or a second driving electrode according to Embodiment 1;

[0036] Figure 10 is a graph showing the retardation distribution in an upper region and a lower region according to Embodiment 1;

[0037] Figure 11 is a plan view showing a first driving electrode and a second driving electrode according to Embodiment 2;

[0038] Figure 12 is a schematic diagram showing a cross-section of the optical panel in an installed state according to Embodiment 2;

[0039] Figure 13 is a schematic diagram showing a cross-section of an optical panel according to Embodiment 3;

[0040] Figure 14 is a schematic diagram showing a cross-section of the optical panel in an installed state according to Embodiment 3;

[0041] Figure 15 is a schematic diagram showing the dispersion state of electrophoretic particles according to Embodiment 3;

[0042] Figure 16 is a plan view showing the third driving electrode and the fourth driving electrode according to Embodiment 4;

[0043] Figure 17 is a plan view showing the third pair of electrodes and the fourth pair of electrodes according to Embodiment 4;

[0044] Figure 18 is a schematic diagram showing a cross section of an optical panel according to a modification example;

[0045] Figure 19 is a diagram showing the potentials of a driving electrode and a common electrode according to a modification example;

[0046] Figure 20 is a plan view showing a driving electrode according to a modification example;

[0047] Figure 21 is a plan view showing a driving electrode according to a modification example; and

[0048] Figure 22 is a diagram for explaining the function of an optical panel according to a modification example. DETAILED DESCRIPTION

[0049] The following describes an optical panel according to various embodiments with reference to the drawings.

[0050] Embodiment 1

[0051] Reference Figures 1 - 10 describes the optical panel 100 according to the present embodiment. The optical panel 100 serves as a liquid crystal lens (liquid crystal light deflection element). For example, as Figure 1 shown, the optical panel 100 is provided on the display surface side of the liquid crystal display panel 200, and together with the liquid crystal display panel 200, forms a display device 300 for displaying two-dimensional images and three-dimensional images. The display light of the liquid crystal display panel 200 is linearly polarized light with the Y direction as the polarization direction.

[0052] The optical panel 100 (display device 300) has a front surface 101 perpendicular to the ground. In the present embodiment, for ease of understanding, a description is given in which the vertical direction is referred to as the "Y-axis direction", the direction parallel to the ground and the front surface 101 of the optical panel 100 is referred to as the "X-axis direction", and the front surface direction perpendicular to the X-axis direction and the Y-axis direction is referred to as the "Z-axis direction". In addition, when the optical panel 100 is installed, the +Y direction is upward, so the +Y direction can also be referred to as upward or vertically upward, and the -Y direction can also be referred to as downward or vertically downward. These constraints also apply to other embodiments.

[0053] The optical panel 100 includes a variable region 102 where the refractive index distribution changes and a peripheral region 104 surrounding the variable region 102. In the installed state, the variable region 102 is bisected into an upper region 102A placed vertically upward and a lower region 102B placed vertically downward. The variable region 102 varies between a state where the refractive index distribution is uniform over the entire surface and a state where the refractive index distribution changes periodically in the X-axis direction. In the present embodiment, the state where the refractive index distribution is uniform over the entire surface is referred to as the "first state", and the state where the refractive index distribution changes periodically in the X-axis direction is referred to as the "second state".

[0054] When the variable region 102 of the optical panel 100 is in the first state, the display device 300 displays a two-dimensional 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 three-dimensional image.

[0055] Next, the specific configuration of the optical panel 100 is described. As Figure 2 shown, the optical panel 100 includes a first light-transmitting substrate 10, a second light-transmitting substrate 30, and a liquid crystal 50. The first light-transmitting substrate 10 and the second light-transmitting substrate 30 sandwich the liquid crystal 50.

[0056] The first light-transmitting substrate 10 transmits visible light. In one example, the first light-transmitting substrate 10 is implemented as a flat glass substrate. As Figure 2 shown, the first light-transmitting substrate 10 includes a plurality of drive electrodes 12 and an alignment film 14.

[0057] As Figure 2 and Figure 3As shown, the driving electrodes 12 are arranged on the main surface 10a on the liquid crystal 50 side of the first light-transmissive substrate 10. Each driving electrode 12 has a rectangular shape and extends along the Y-axis direction. The driving electrodes 12 are arranged in the variable region 102 at a predetermined pitch in the X-axis direction. Each driving electrode 12 is bisected into a first driving electrode 12A and a second driving electrode 12B.

[0058] Each first driving electrode 12A has a rectangular shape. The first driving electrode 12A extends along the Y-axis direction and is located in the upper region 102A of the variable region 102. Each second driving electrode 12B has a rectangular shape. The second driving electrode 12B extends along the Y-axis direction and is located in the lower region 102B of the variable region 102. The first driving electrode 12A and the second driving electrode 12B are arranged along the Y-axis direction. Both the first driving electrode 12A and the second driving electrode 12B are connected to the controller 310 via wirings (not shown). The driving electrodes 12 (the first driving electrode 12A and the second driving electrode 12B) are formed as a conductive film that transmits visible light. In one example, the driving electrodes 12 are formed of indium tin oxide (ITO).

[0059] The alignment film 14 is arranged on the main surface 10a, the first driving electrode 12A, and the second driving electrode 12B. The alignment film 14 aligns the liquid crystal 50 in the Y-axis direction. In one example, the alignment film 14 is implemented as a polyimide alignment film that has been subjected to an alignment process.

[0060] The second light-transmissive substrate 30 transmits visible light. In one example, the second light-transmissive substrate 30 is implemented as a flat glass substrate. As Figure 2 shown, the second light-transmissive substrate 30 faces the first light-transmissive substrate 10. The second light-transmissive substrate 30 is fixed to the first light-transmissive substrate 10 by a sealing material 70. The second light-transmissive substrate 30 includes a common electrode 32 and an alignment film 34.

[0061] The common electrode 32 is arranged on the main surface 30a on the liquid crystal 50 side of the second light-transmissive substrate 30. As Figure 2 and Figure 4 shown, the common electrode 32 is formed in a rectangular shape. The common electrode 32 faces the first driving electrode 12A and the second driving electrode 12B. The common electrode 32 is connected to the controller 310 via wirings (not shown). The common electrode 32 is formed as a conductive film that transmits visible light. In one example, the common electrode 32 is formed of ITO.

[0062] The alignment film 34 is arranged on the common electrode 32. The alignment film 34 aligns the liquid crystal 50 in the Y-axis direction. In one example, the alignment film 34 is implemented as a polyimide alignment film that has been subjected to an alignment process.

[0063] The liquid crystal 50 is sandwiched between the first light-transmissive substrate 10 and the second light-transmissive substrate 30. In one example, the liquid crystal 50 is implemented as a positive nematic liquid crystal. The liquid crystal 50 is aligned by the alignment films 14 and 34 in the Y-axis direction.

[0064] Next, the operation of the optical panel 100 is described. Due to the change in the alignment of the liquid crystal 50, the optical panel 100 functions as a lenticular lens array.

[0065] In one example, when the potential 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 are set to the same potential (e.g., ground potential) by the controller 310, no voltage is applied to the liquid crystal 50. Therefore, the liquid crystal 50 remains aligned in the Y-axis direction. In this case, the variable region 102 is in a state where the refractive index distribution is uniform over the entire surface (i.e., the first state), and the optical panel 100 does not function as a lenticular lens array.

[0066] At the same time, as Figure 5 shown, when the potential of the common electrode 32 is set to ground potential and the potentials of the drive electrodes 12a - 12e arranged in the X-axis direction increase in the order of drive electrodes 12a, 12e > drive electrodes 12b, 12d > drive electrode 12c, the rise 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 is in a state where the refractive index distribution changes in the X-axis direction at a predetermined period (i.e., 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.

[0067] The optical panel 100 is mounted with the front surface 101 including the variable region 102 perpendicular to the ground. Therefore, as Figure 6 shown, the liquid crystal 50 is biased by gravity to the lower region 102B in 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 is greater than the thickness D1 of the liquid crystal 50 in the upper region 102A of the optical panel 100. 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 in the case where 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, a difference in the focal length (delay) of the lenticular lens appears between the upper region 102A and the lower region 102B. The difference between the focal length of the upper region 102A and the focal length of the lower region 102B causes a deterioration in the quality of the three-dimensional image displayed by the display device 300.

[0068] Note that for ease of understanding,Figure 6 The alignment films 14 and 34 and the shading of various components are omitted. The shading of the alignment films 14 and 34 and / or various components may also be omitted from the following drawings.

[0069] Therefore, in the present embodiment, a voltage is applied to the liquid crystal 50 in the lower region 102B by the common electrode 32 and the second driving electrode 12B, and this voltage is higher than the voltage applied to the liquid crystal 50 in the upper region 102A by the common electrode 32 and the first driving electrode 12A. As a result, the inconsistency of the optical characteristics (specifically, the focal length inconsistency, retardation inconsistency, etc.) between the upper region 102A and the lower region 102B can be suppressed.

[0070] Hereinafter, the case where a single lenticular lens (lens pitch: 147 μm) is formed by 13 driving electrodes 12 (the first driving electrode 12A and the second driving electrode 12B) arranged in the X direction is used as an example to describe the distribution of the retardation R in the upper region 102A and the lower region 102B, where the refractive index anisotropy Δn of the liquid crystal 50 is set to 0.2556, the thickness D1 of the liquid crystal 50 in the upper region 102A is set to 50 μm, and the thickness D2 of the liquid crystal 50 in the lower region 102B is set to 55 μm. The distribution of the 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 (the display light of the liquid crystal display panel 200). In the present embodiment, as described above, the rise of the liquid crystal molecules M changes along the X-axis direction according to the applied voltage, and as a result, a distribution of the refractive index anisotropy Δn with respect to the incident light is generated.

[0071] As Figure 7 shown, in the case where the potential of the common electrode 32 is set to the ground potential and the potentials of the first to thirteenth first driving electrodes 12A or second driving electrodes 12B are controlled in order from the -X direction (comparative example), so that 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, as Figure 8 shown, a difference (inconsistency) in the retardation R appears between the upper region 102A and the lower region 102B.

[0072] In the present embodiment, as Figure 9 shown, 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 is applied to the liquid crystal 50 in the lower region 102B, and this voltage is higher than the voltage applied to the liquid crystal 50 in the upper region 102A. In this case, as Figure 10 shown, the retardation R in the lower region 102B can be made to match the retardation R in the upper region 102A.

[0073] As described above, a voltage is applied to the liquid crystal 50 in the lower region 102B, which is higher than the voltage applied to the liquid crystal 50 in the upper region 102A. Therefore, the inconsistency in optical characteristics between the upper region 102A and the lower region 102B can be suppressed.

[0074] Embodiment 2

[0075] In Embodiment 1, a voltage is applied to the liquid crystal 50 in the lower region 102B, which is higher than the voltage applied to the liquid crystal 50 in the upper region 102A. However, in the optical panel 100, it is possible to configure the liquid crystal 50 in a partial region of the lower region 102B to have a voltage higher than the voltage applied to the liquid crystal 50 in the upper region 102A.

[0076] Similar to the optical panel 100 of Embodiment 1, the optical panel 100 of this embodiment is provided with a front surface 101 perpendicular to the ground. In addition, similar to the optical panel 100 of Embodiment 1, the optical panel 100 of this embodiment includes a variable region 102 and a surrounding region 104. The optical panel 100 of this embodiment includes a first light-transmitting substrate 10, a second light-transmitting substrate 30, and a liquid crystal 50. The operation of the optical panel 100 of this embodiment and the configuration of the second light-transmitting substrate 30 and the liquid crystal 50 are the same as those in Embodiment 1. Therefore, the first light-transmitting substrate 10 and the region where a voltage higher than the voltage applied to the liquid crystal 50 in the upper region 102A is applied are described.

[0077] Similar to the first light-transmitting substrate 10 of Embodiment 1, the first light-transmitting substrate 10 of this embodiment includes a plurality of driving electrodes 12 and an alignment film 14. The configuration of the alignment film 14 is the same as that in Embodiment 1.

[0078] Similar to the driving electrode 12 of Embodiment 1, the driving electrode 12 of this embodiment is provided on the main surface 10a of the first light-transmitting substrate 10. Each of the driving electrodes 12 has a rectangular shape. The driving electrode 12 of this embodiment extends along the Y-axis direction and is arranged at a predetermined interval in the X-axis direction. The driving electrode 12 of this embodiment is divided into two regions, namely a first driving electrode 12A and a second driving electrode 12B.

[0079] As Figure 11 and Figure 12 shown, the first driving electrode 12A of this embodiment extends along the Y-axis direction and is provided in the 2 / 3 region 102C located on the vertically upper side in the variable region 102 including the upper region 102A. The second driving electrode 12B of this embodiment extends along the Y-axis direction and is provided in the 1 / 3 region 102D located on the vertically lower side in the variable region 102. The region 102D corresponds to the 2 / 3 region located on the vertically lower side in the lower region 102B.

[0080] When the optical panel 100 is installed with the front surface 101 perpendicular to the ground, depending on the materials of the first light-transmitting substrate 10 and the second light-transmitting substrate 30, the thickness of the liquid crystal 50, etc., the thickness of the liquid crystal 50 in the narrow area on the vertically downward side in the lower region 102B can increase. Therefore, in this embodiment, a voltage is applied to the liquid crystal 50 in the region 102D by the common electrode 32 and the second driving electrode 12B, and this voltage is higher than the voltage applied to the liquid crystal 50 in the region 102C by the common electrode 32 and the first driving electrode 12A. As a result, similar to the upper region 102A and the lower region 102B in Embodiment 1, the inconsistency of the optical characteristics (inconsistency of retardation R) between the region 102C and the region 102D can be suppressed.

[0081] Embodiment 3

[0082] In Embodiments 1 and 2, the first light-transmitting substrate 10 and the second light-transmitting substrate 30 sandwich the liquid crystal 50. However, a configuration in which the first light-transmitting substrate 10 and the second light-transmitting substrate 30 sandwich the electrophoretic medium is also possible.

[0083] Similar to the optical panel 100 of Embodiment 1, the optical panel 100 of this embodiment is installed with the front surface 101 perpendicular to the ground. In addition, similar to the optical panel 100 of Embodiment 1, the optical panel 100 of this embodiment includes a variable region 102 and a peripheral region 104. The optical panel 100 of this embodiment includes a first light-transmitting substrate 10 and a second light-transmitting substrate 30. Instead of the liquid crystal 50, the optical panel 100 of this embodiment includes an electrophoretic medium 80 containing a light-transmitting dispersion medium 82 and electrophoretic particles 84.

[0084] In this embodiment, the variable region 102 varies between a state where light is blocked on the entire surface and a state where regions blocking light and regions transmitting light appear on the entire surface. That is, the optical panel 100 of this embodiment functions as a light control element. In this embodiment, the state where light is blocked on the entire surface is referred to as the "first state", and the state where regions blocking light and regions transmitting light appear on the entire surface is referred to as the "second state".

[0085] Similar to the first light-transmitting substrate 10 of Embodiments 1 and 2, the first light-transmitting substrate 10 of this embodiment transmits visible light. As Figure 13 shown, the first light-transmitting substrate 10 of this embodiment includes a plurality of driving electrodes 12 and an insulating layer 16.

[0086] Similar to the driving electrode 12 of Embodiment 2, each of the driving electrodes 12 in this embodiment has a rectangular shape and extends along the Y-axis direction. In addition, the driving electrodes 12 in this embodiment are arranged in the variable region 102 at a predetermined interval in the X-axis direction. Further, similar to Embodiment 2, the driving electrode 12 is divided into two regions, namely the first driving electrode 12A and the second driving electrode 12B. The first driving electrode 12A is arranged in the region 102C, and the second driving electrode 12B is arranged in the region 102D( Figure 11 ). Similarly in this embodiment, each of the first driving electrode 12A and the second driving electrode 12B is connected to the controller 310 via wiring (not shown). The driving electrode 12 in this embodiment is formed of a metal such as aluminum (Al), molybdenum (Mo), etc.

[0087] The insulating layer 16 is provided on the main surface 10a, the first driving electrode 12A, and the second driving electrode 12B. In one example, the insulating layer 16 is formed of silicon oxide (SiO2).

[0088] Similar to the second light-transmitting substrate 30 of Embodiments 1 and 2, the second light-transmitting substrate 30 in this embodiment transmits visible light. The second light-transmitting substrate 30 faces the first light-transmitting substrate 10. The second light-transmitting substrate 30 is fixed to the first light-transmitting substrate 10 by a sealing material 70. The second light-transmitting substrate 30 and the first light-transmitting substrate 10 sandwich the electrophoretic medium 80. As Figure 13 shown, the second light-transmitting substrate 30 in this embodiment includes a plurality of counter electrodes 33 and an insulating layer 36.

[0089] As Figure 13 and Figure 14 shown, each of the counter electrodes 33 has a rectangular shape and extends in the Y-axis direction. In this embodiment, one of the counter electrodes 33 faces one of the driving electrodes 12 (the first driving electrode 12A and the second driving electrode 12B obtained by dividing one of the driving electrodes 12). The counter electrode 33 is formed of a metal such as aluminum (Al), molybdenum (Mo), etc. The counter electrode 33 is connected to the controller 310.

[0090] The insulating layer 36 is provided on the main surface 30a of the second light-transmitting substrate 30 and on the counter electrode 33. In one example, the insulating layer 36 is formed of silicon oxide (SiO2).

[0091] The electrophoretic medium 80 is sandwiched between the first light-transmitting substrate 10 and the second light-transmitting substrate 30. The electrophoretic medium 80 includes a light-transmitting dispersion medium 82 and electrophoretic particles 84.

[0092] The light-transmitting dispersion medium 82 transmits visible light. The light-transmitting dispersion medium 82 disperses the electrophoretic particles 84.

[0093] The electrophoretic particles 84 are dispersed in the light-transmitting dispersion medium 82 and absorb visible light. The electrophoretic particles 84 are positively or negatively charged. The dispersion state of the electrophoretic particles 84 in the light-transmitting dispersion medium 82 changes according to the voltage applied from the first drive electrode 12A or the second drive electrode 12B and the counter electrode 33. In one example, the electrophoretic particles 84 are implemented as charged carbon black particles. In this embodiment, it is assumed that the electrophoretic particles 84 are negatively charged.

[0094] Next, the operation of the optical panel 100 of the present embodiment is described. Due to the change in the dispersion state of the electrophoretic particles 84, the optical panel 100 of the present embodiment functions as a light control element.

[0095] In one example, when the potential of the driving electrode 12 (the first driving electrode 12A and the second driving electrode 12B) of the first light-transmitting substrate 10 and the potential of the counter electrode 33 of the second light-transmitting substrate 30 are set to the same potential by the controller 310, the electrophoretic particles 84 that absorb visible light are uniformly dispersed throughout the variable region 102. Therefore, the variable region 102 of the optical panel 100 of the present embodiment absorbs visible light and is in a state where visible light is blocked over the entire surface (specifically, the first state).

[0096] At the same time, if Figure 15 As shown, when the potential of the driving electrode 12 (the first driving electrode 12A and the second driving electrode 12B) of the first light-transmitting substrate 10 is set to be higher than the potential of the counter electrode 33 of the second light-transmitting substrate 30, the electrophoretic particles 84 gather on the driving electrode 12 (the first driving electrode 12A or the second driving electrode 12B). As a result, the electrophoretic particles 84 have gathered on the driving electrode 12 to block the visible light and the region 112 and the region 114 that transmits the visible light appear. Therefore, the variable region 102 of the optical panel 100 of the present embodiment presents a state (specifically, the second state) in which the region 112 that blocks the visible light and the region 114 that transmits the visible light appear on the entire surface.

[0097] The optical panel 100 of the present embodiment is also provided with a front surface 101 including a variable region 102 perpendicular to the ground. Therefore, the electrophoretic medium 80 (light-transmitting dispersion medium 82 and electrophoretic particles 84) is biased to a vertically downward region (region 102D in the present embodiment) in the variable region 102, and a thickness (box thickness) D2 of the electrophoretic medium 80 in the vertically downward region (region 102D) becomes greater than a thickness D1 of the electrophoretic medium 80 in the upper region 102A.

[0098] When the mobility is μ, the electric field strength (voltage per unit distance) is E, the effective charge is Q, the radius of the electrophoretic particle 84 is r, the viscosity of the light-transmitting 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, the moving speed v of the electrophoretic particle 84 is represented by the following equation (1).

[0099]

[0100] When the thickness (cell thickness) of the electrophoretic medium 80 increases, the distance L between the driving electrode 12 and the counter electrode 33 increases, and based on Equation (1), the moving speed v of the electrophoretic particle 84 decreases. Therefore, when the same voltage is applied to the electrophoretic medium 80 in the region 102C and the electrophoretic medium 80 in the region 102D, the movement of the electrophoretic particles 84 in the region 102D is slower than the movement of the electrophoretic particles 84 in the region 102C. This causes a difference in the response time for the transition from the first state to the second state between the region 102C and the region 102D.

[0101] In the present embodiment, a voltage higher than the voltage applied to the electrophoretic medium 80 in the region 102C by the counter electrode 33 and the first driving electrode 12A is applied to the electrophoretic medium 80 in the region 102D by the counter electrode 33 and the second driving electrode 12B. As a result, the difference in the response time (inconsistent response characteristics) between the region 102C and the region 102D can be suppressed. For example, when the thickness D1 of the region 102C (upper region 102A) is set to 25 μm and the thickness D2 of the region 102D is set to 30 μm, by applying 24.0 V to the electrophoretic medium 80 in the region 102C and 28.8 V to the electrophoretic medium 80 in the region 102D, the difference in the response time between the region 102C and the region 102D can be suppressed.

[0102] Example 4

[0103] In Example 3, the driving electrode 12 (the first driving electrode 12A and the second driving electrode 12B) and the counter electrode 33 are arranged in the X-axis direction at the same arrangement pitch, and a voltage is applied to the electrophoretic medium 80. However, it is possible to have a configuration in which the arrangement pitch of the driving electrode 12 and the counter electrode 33 arranged in the X-axis direction in the region 102C is different from the arrangement pitch of the driving circuit 12 and the counter electrode 33 arranged in the X-axis direction in the region 102D.

[0104] Similar to the optical panel 100 of Embodiment 3, the optical panel 100 of this embodiment is mounted with a front surface 101 perpendicular to the ground. In addition, similar to the optical panel 100 of Embodiment 3, the optical panel 100 of this embodiment includes a variable region 102 and a surrounding region 104. The optical panel 100 of this embodiment includes a first light-transmissive substrate 10, a second light-transmissive substrate 30, and an electrophoretic medium 80. The optical panel 100 of this embodiment serves as a light control element.

[0105] Except that the first light-transmissive substrate 10 includes a third driving electrode 18 and a fourth driving electrode 19 instead of the driving electrode 12 (the first driving electrode 12A and the second driving electrode 12B), and the second light-transmissive substrate 30 includes a third pair of electrodes 38 and a fourth pair of electrodes 39 instead of the pair of electrodes 33, the configuration of the optical panel 100 of this embodiment is the same as that of the optical panel 100 of Embodiment 3. Here, the third driving electrode 18 and the fourth driving electrode 19 of the first light-transmissive substrate 10, and the third pair of electrodes 38 and the fourth pair of electrodes 39 of the second light-transmissive substrate 30 are described.

[0106] As Figure 16 shown, the third driving electrode 18 of the first light-transmissive substrate 10 is provided on the main surface 10a of the first light-transmissive substrate. Each of the third driving electrodes 18 has a rectangular shape and extends along the Y-axis direction. The third driving electrodes 18 are provided in the region 102C and are arranged along the X-axis direction at a predetermined first arrangement pitch P1.

[0107] Similar to the third driving electrode 18, the fourth driving electrode 19 of the first light-transmissive substrate 10 is provided on the main surface 10a of the first light-transmissive substrate 10 and extends along the Y-axis direction. The fourth driving electrode 19 is provided in the region 102D. The fourth driving electrodes 19 are arranged along the X-axis direction at a predetermined second arrangement pitch P2 that is narrower than the first arrangement pitch P1 of the third driving electrodes 18.

[0108] As Figure 17 shown, the third pair of electrodes 38 of the second light-transmissive substrate 30 is provided on the main surface 30a of the second light-transmissive substrate 30. Each of the third pair of electrodes 38 has a rectangular shape and extends along the Y-axis direction. In the region 102C, the third pair of electrodes 38 are arranged along the X-axis direction at the same arrangement pitch as the first arrangement pitch P1 of the third driving electrodes 18. Each of the third pair of electrodes 38 faces each of the third driving electrodes 18.

[0109] Like the third pair of electrodes 38, the fourth pair of electrodes 39 of the second light-transmissive substrate 30 are provided on the main surface 30a of the second light-transmissive substrate 30 and extend along the Y-axis direction. In the region 102D, the fourth pair of electrodes 39 are arranged along the X-axis direction at the same arrangement pitch as the second arrangement pitch P2 of the fourth driving electrodes 19. Each of the fourth pair of electrodes 39 faces each of the fourth driving electrodes 19.

[0110] In the present embodiment, the second arrangement pitch P2 of the fourth driving electrodes 19 and the fourth pair of electrodes 39 provided in the region 102D is narrower than the first arrangement pitch P1 of the third driving electrodes 18 and the third pair of electrodes 38 provided in the region 102C. Therefore, even when the voltage applied to the electrophoretic medium 80 by the third driving electrodes 18 and the third pair of electrodes 38 is the same as the voltage applied to the electrophoretic medium 80 by the fourth driving electrodes 19 and the fourth pair of electrodes 39, the electric field intensity acting on the thick electrophoretic medium 80 in the region 102D can be close to the electric field intensity acting on the thin electrophoretic medium 80 in the region 102C, and the difference in response time (inconsistent response characteristics) between the region 102C and the region 102D can be suppressed.

[0111] Modification example

[0112] Although the embodiments have been described above, various modifications can be made to the present disclosure without departing from the spirit and scope of the present disclosure.

[0113] In Embodiments 1-4, the front surface 101 of the optical panel 100 is installed perpendicular to the ground. However, it is sufficient that the front surface 101 of the optical panel 100 is installed inclined with respect to the ground.

[0114] 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. Further, in Embodiments 2 and 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 2 / 3 region vertically downward in the lower region 102B). However, in the optical panel 100, it is sufficient to apply a voltage higher than the voltage applied to the liquid crystal 50 or the electrophoretic medium 80 in the upper region 102A 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.

[0115] It is possible that the optical panel 100 of Embodiment 3 does not include the configurations of the insulating layers 16 and 36.

[0116] In Embodiment 4, the second arrangement pitch P2 of the fourth driving electrode 19 and the fourth pair of electrodes 39 provided in the region 102D is narrower than the first arrangement pitch P1 of the third driving electrode 18 and the third pair of electrodes 38 provided in the region 102C. However, for the optical panel 100, it is sufficient that the arrangement pitch of the driving electrodes provided in at least a part of the lower region 102B is narrower than the arrangement pitch of the driving circuit provided in the upper region 102A according to the thickness of the electrophoretic medium 80 in the lower region 102B.

[0117] In Embodiments 1-3, the driving electrode 12 is divided into a first driving electrode 12A and a second driving electrode 12B. In the optical panel 100 of Embodiments 1 and 2, it is possible to configure the common electrode 32 to be divided into two sections and not divide the driving electrode 12. As Figure 18 shown, for example, it is possible to configure the first light-transmissive substrate 10 to include the undivided driving electrode 12, and the second light-transmissive substrate 30 to include the 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 Figure 19 shown, by setting the potential of the first common electrode 32A to zero and reversing 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 can be applied to the liquid crystal 50 in the lower region 102B.

[0118] In addition, in Embodiment 3, it is possible to configure the counter electrode 33 to be divided into two sections and not divide the driving electrode 12.

[0119] It is possible to configure the driving electrode 12 to be divided into three or more sections. As Figure 20 shown, for example, it is possible to configure the driving electrode 12 to be divided into four sections, with the first driving electrode 12A provided in the upper region 102A of the first light-transmissive substrate 10 and the driving electrodes 12C-12E provided in the lower region 102B of the first light-transmissive substrate 10. In this case, according to the thickness of the liquid crystal 50 or the electrophoretic medium 80, it is sufficient to apply mutually different voltages to the liquid crystal 50 or the electrophoretic medium 80 in the regions corresponding to each of the driving electrodes 12C-12E, which is higher than the voltage applied to the liquid crystal 50 or the electrophoretic medium 80 in the upper region 102A. Such a configuration makes it possible to further suppress the inconsistency of the optical characteristics or the response time of the optical panel 100.

[0120] In addition, it is possible to configure the common electrode 32 or the counter electrode 33 to be divided into three or more sections. Such a configuration makes it possible to further suppress the inconsistency of the optical characteristics or the response time of the optical panel 100.

[0121] The extending direction of electrodes such as the driving electrode 12 (the first driving electrode 12A and the second driving electrode 12B), the third driving electrode 18, etc. can be set as required. For example, as Figure 21 shown, in the optical panel 100 of Embodiment 1, it is possible to configure the driving electrode 12 (the first driving electrode 12A and the second driving electrode 12B) to be inclined counterclockwise by an angle θ with respect to the Y-axis direction. In this case, as Figure 22 shown, the optical panel 100 including the liquid crystal 50 functions as a lenticular lens array, in which the lenticular lenses are inclined by an angle θ with respect to the arrangement direction (Y-axis direction) of the pixels (viewpoint pixels for displaying multiple viewpoint images) 202 of the liquid crystal display panel 200. Therefore, the optical panel 100 can not only distribute the display light from the pixels 202 arranged along the X-axis direction in different directions, but also distribute the display light from the pixels 202 arranged along the Y-axis direction in different directions. In Figure 22 the example shown, the viewpoint images can be presented in six directions. In Figure 22 the numbers attached to each of the pixels 202 indicate the numbers of the viewpoint images.

[0122] In Embodiment 1, the display device 300 displays two-dimensional images and three-dimensional images. However, it is possible to configure the display device 300 as a multi-screen display device in which the lenticular lens array presents different images to observers at different positions.

[0123] For purposes of explanation, some example embodiments have been described above. Although the above discussion has given specific embodiments, those skilled in the art will recognize that changes may be made in form and detail without departing from the broader spirit and scope of the invention. Therefore, the specification and drawings are to be regarded as illustrative rather than restrictive. Thus, this detailed description should not be considered restrictive, and the scope of the invention is defined only by the included claims and all equivalents thereto.

Claims

1. An optical panel, comprising: a first light-transmitting substrate; a second light-transmitting substrate facing the first light-transmitting substrate; Liquid crystal or electrophoretic medium including a light-transmitting dispersion medium and electrophoretic particles, wherein the liquid crystal or the electrophoretic medium is sandwiched between the first light-transmitting substrate and the second light-transmitting substrate, wherein a front surface including a variable area in which the optical properties vary between two states over the entire surface, mounted obliquely relative to the ground, In the installed state, the variable area is divided into an upper area placed vertically upward and a lower area placed vertically downward, and In the case where 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 a 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 at least a portion of the lower region.

2. The optical panel according to claim 1, wherein In the case where a voltage is applied to the liquid crystal or electrophoretic medium to set the variable region to one of the two states, A voltage higher than a voltage applied to the liquid crystal or the electrophoretic medium in the upper region is applied to the liquid crystal or the electrophoretic medium located in a 2 / 3 region located vertically downward in the lower region.

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

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

5. The optical panel according to claim 1 or 2, further comprising: A driving electrode and a common electrode, which apply a voltage to the liquid crystal or the electrophoretic medium, wherein The driving electrode and the common electrode are divided according to the position of the area where a voltage higher than a voltage applied to the liquid crystal or the electrophoretic medium in the upper area is applied to the liquid crystal or the electrophoretic medium.

6. An optical panel, comprising: An electrophoretic medium, comprising a light-transmitting dispersion medium and electrophoretic particles; A first light-transmitting substrate and a second light-transmitting substrate sandwiching the electrophoretic medium; and, A plurality of electrodes for applying a voltage to the electrophoretic medium, wherein a front surface including a variable area in which the optical properties vary between two states over the entire surface, mounted obliquely relative to the ground, In the installed state, the variable area is divided into an upper area placed vertically upward and a lower area placed vertically downward, and An arrangement pitch of the electrodes disposed in at least a portion of the lower region is narrower than an arrangement pitch of the electrodes disposed in the upper region.

7. The optical panel according to claim 6, wherein: The arrangement pitch of the electrodes disposed in a 2 / 3 region located vertically downward in the lower region is narrower than the arrangement pitch of the electrodes disposed in the upper region.

8. The optical panel according to claim 6 or 7, wherein In one of the two states of the variable region, light is transmitted, and In the other of the two states of the variable region, light is blocked.

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