Optical element

Abstract

Provided is an optical element capable of reducing moire and well controlling light distribution. An optical element (10) includes at least two liquid crystal cells (110, 120) stacked, each of the at least two liquid crystal cells including: a first substrate (111-1, 121-1) in which a first transparent electrode (112-1, 122-1) and a second transparent electrode (112-2, 122-2) are alternately arranged in a first direction; a second substrate (111-2, 121-2) in which a third transparent electrode (112-3, 122-3) and a fourth transparent electrode are alternately arranged in a second direction intersecting the first direction; and a liquid crystal layer (113, 123) between the first substrate and the second substrate, the second transparent electrode including a first bent portion bent toward the first direction, and the fourth transparent electrode including a second bent portion bent toward the second direction.

Description

TECHNICAL FIELD

[0001] One embodiment of the present application relates to an optical element using liquid crystal. BACKGROUND

[0002] Conventionally, an optical element adjusting a voltage applied to liquid crystal to utilize a refractive index change of the liquid crystal, a so-called liquid crystal lens, is known. In addition, development of an illuminating device using a light source and the liquid crystal lens is being promoted (for example, refer to Patent Document 1, Patent Document 2, or Patent Document 3).

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-317879

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2010-230887

[0007] Patent Document 3: Japanese Patent Application Laid-Open No. 2014-160277 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] However, in a case where liquid crystal cell layers constituting a liquid crystal lens are stacked, if the shape and the arrangement of electrodes applying a voltage to liquid crystal are the same, the distribution of the direction in which light is refracted becomes the same, and as a result, according to the stacking manner of the liquid crystal cell, a Moire fringe due to interference of light or coloring due to wavelength dependence of the refractive index is sometimes generated. Although a configuration in which electrodes are formed in a manner different in the distance between electrodes is also proposed in a case where linear electrodes are arranged in parallel, if the distance between electrodes is too large, liquid crystal of the liquid crystal cell becomes difficult to orient, and thus, the diffusion performance of light (i.e., the light distribution of light) can possibly decrease.

[0010] One embodiment of the present application is made in view of the above problem, and an object thereof is to provide an optical element capable of reducing a Moire fringe while controlling light distribution well.

[0011] TECHNICAL SOLUTION FOR SOLVING THE PROBLEMS

[0012] An optical element according to one embodiment of the present application includes at least two liquid crystal cells stacked, each of the at least two liquid crystal cells including: a first substrate in which a first transparent electrode and a second transparent electrode are alternately arranged in a first direction; a second substrate in which a third transparent electrode and a fourth transparent electrode are alternately arranged in a second direction intersecting the first direction; and a liquid crystal layer between the first substrate and the second substrate, the second transparent electrode including a first bent portion bent toward the first direction, and the fourth transparent electrode including a second bent portion bent toward the second direction. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a schematic perspective view of an optical element according to an embodiment of the present application.

[0014] Figure 2A is a schematic cross-sectional view of an optical element according to an embodiment of the present application.

[0015] Figure 2B is a schematic cross-sectional view of an optical element according to an embodiment of the present application.

[0016] Figure 3A is a schematic cross-sectional view showing alignment of liquid crystals of a liquid crystal layer in an optical element according to an embodiment of the present application.

[0017] Figure 3B is a schematic cross-sectional view showing alignment of liquid crystals of a liquid crystal layer in an optical element according to an embodiment of the present application.

[0018] Figure 4A is a schematic cross-sectional view showing alignment of liquid crystal molecules of a liquid crystal layer in an optical element according to an embodiment of the present application when a voltage is applied.

[0019] Figure 4B is a schematic cross-sectional view showing alignment of liquid crystal molecules of a liquid crystal layer in an optical element according to an embodiment of the present application when a voltage is applied.

[0020] Figure 5A is a schematic cross-sectional view illustrating control of light distribution by an optical element according to an embodiment of the present application.

[0021] Figure 5B is a schematic cross-sectional view illustrating control of light distribution by an optical element according to an embodiment of the present application.

[0022] Figure 6 is a timing chart showing applied potentials to each transparent electrode included in an optical element according to an embodiment of the present application.

[0023] Figure 7 is a graph showing front surface relative luminance with respect to d / p in a liquid crystal cell of an optical element according to an embodiment of the present application.

[0024] Figure 8 is a schematic view illustrating shapes and arrangement of a first transparent electrode and a second transparent electrode of a first liquid crystal cell of an optical element according to an embodiment of the present application.

[0025] Figure 9is a schematic view illustrating shapes and configurations of a first transparent electrode, a second transparent electrode, a third transparent electrode, and a fourth transparent electrode of a first liquid crystal cell of an optical element according to an embodiment of the present application.

[0026] Figure 10 is a schematic view illustrating shapes and configurations of a first transparent electrode and a second transparent electrode of a first liquid crystal cell of an optical element according to an embodiment of the present application.

[0027] Figure 11 is a schematic view illustrating shapes and configurations of a first transparent electrode and a second transparent electrode of a first liquid crystal cell of an optical element according to an embodiment of the present application.

[0028] Figure 12 is a schematic view illustrating shapes and configurations of a first transparent electrode and a second transparent electrode of a first liquid crystal cell of an optical element according to an embodiment of the present application.

[0029] Figure 13 is a schematic view illustrating shapes and configurations of a first transparent electrode and a second transparent electrode of a first liquid crystal cell of an optical element according to an embodiment of the present application.

[0030] Figure 14 is a schematic view illustrating configurations in a stack of a first transparent electrode and a second transparent electrode of a first liquid crystal cell and a first transparent electrode and a second transparent electrode of a second liquid crystal cell of an optical element according to an embodiment of the present application. DETAILED DESCRIPTION

[0031] Hereinafter, in each embodiment of the present application, description will be made with reference to the drawings and the like. However, the present application can be implemented in various ways within a range not departing from the gist of the technical idea thereof, and is not to be construed as being limited to the contents described in the following embodiments.

[0032] In order to make the description clearer, the width, the thickness, the shape, and the like of each portion are schematically shown in the drawings, but are merely one example, and the illustrated shapes themselves do not limit the explanation of the present application. In addition, in the drawings, the same reference numerals are attached to elements having the same function as those described with reference to the already appearing drawings, even in other drawings, and sometimes the repeated description is omitted.

[0033] In a case where a plurality of structures are formed by processing a certain film, each structure sometimes has a different function or role, and in addition, the substrate for forming each structure is sometimes different. However, the plurality of structures originate from a film formed as the same layer in the same process, and have the same material. Thus, the plurality of films are defined as films present in the same layer.

[0034] When expressing a manner in which another structure is arranged on a certain structure, in the case of only being expressed as "on", unless otherwise specified, both a case in which another structure is arranged in direct contact with a certain structure and a case in which another structure is further arranged above a certain structure with another structure interposed are included.

[0035] <First Embodiment>

[0036] Reference Figures 1-7 An optical element 10 according to an embodiment of the present application will be described.

[0037] [1. Configuration of Optical Element]

[0038] Figure 1 is a schematic perspective view of the optical element 10 according to an embodiment of the present application. As shown in Figure 1 , the optical element 10 includes a first liquid crystal cell 110, a second liquid crystal cell 120, and an optically elastic resin layer 130. The optically elastic resin layer 130 is provided between the first liquid crystal cell 110 and the second liquid crystal cell 120. That is, the first liquid crystal cell 110 and the second liquid crystal cell 120 are stacked in the z-axis direction in such a manner that the optically elastic resin layer 130 is interposed therebetween.

[0039] The optically elastic resin layer 130 can bond and fix the first liquid crystal cell 110 and the second liquid crystal cell 120. As the optically elastic resin layer 130, an optically elastic resin, such as a bonding material including an acrylic resin having light-transmitting properties, can be used.

[0040] Figure 2A and Figure 2B is a schematic cross-sectional view of the optical element 10 according to an embodiment of the present application. Specifically, Figure 2A is a schematic cross-sectional view in the zx plane after being cut along the A1-A2 line shown in Figure 1 , and Figure 2B is a schematic cross-sectional view in the yz plane after being cut along the B1-B2 line shown in Figure 1 . Note that hereinafter, the x-axis direction and the y-axis direction will be sometimes referred to as a first direction and a second direction, respectively.

[0041] The first liquid crystal cell 110 includes a first substrate 111-1, a second substrate 111-2, a first transparent electrode 112-1, a second transparent electrode 112-2, a third transparent electrode 112-3, a fourth transparent electrode 112-4, a liquid crystal layer 113, a first alignment film 114-1, a second alignment film 114-2, and a sealing material 115. The second liquid crystal cell 120 includes a first substrate 121-1, a second substrate 121-2, a first transparent electrode 122-1, a second transparent electrode 122-2, a third transparent electrode 122-3, a fourth transparent electrode 122-4, a liquid crystal layer 123, a first alignment film 124-1, a second alignment film 124-2, and a sealing material 125.

[0042] In Figure 1 In the present embodiment, the optical element 10 including two liquid crystal cells (the first liquid crystal cell 110 and the second liquid crystal cell 120) is shown, but the number of liquid crystal cells included in the optical element 10 is not limited to two. The optical element 10 can include at least two liquid crystal cells. In addition, the plurality of liquid crystal cells included in the optical element 10 need not necessarily have the same structure and be stacked in the same direction, but in the following, the first liquid crystal cell 110 and the second liquid crystal cell 120 are assumed to have the same structure and be stacked in the same direction for convenience. Thus, in the following, only the configuration of the first liquid crystal cell 110 will be described, and the description of the configuration of the second liquid crystal cell 120 will be omitted at times for convenience.

[0043] The first transparent electrode 112-1 and the second transparent electrode 112-2 are provided on the first substrate 111-1. The first transparent electrode 112-1 and the second transparent electrode 112-2 each extend in the y-axis direction, and the first transparent electrode 112-1 and the second transparent electrode 112-2 are alternately arranged in the x-axis direction. In other words, the first transparent electrode 112-1 and the second transparent electrode 112-2 are formed in a comb shape on the first substrate 111-1. In addition, the first alignment film 114-1 is provided on the first substrate 111-1 so as to cover the first transparent electrode 112-1 and the second transparent electrode 112-2.

[0044] The third transparent electrode 112-3 and the fourth transparent electrode 112-4 are provided on the second substrate 111-2. The third transparent electrode 112-3 and the fourth transparent electrode 112-4 each extend in the x-axis direction, and the third transparent electrode 112-3 and the fourth transparent electrode 112-4 are alternately arranged in the y-axis direction. In other words, the third transparent electrode 112-3 and the fourth transparent electrode 112-4 are formed in a comb shape on the second substrate 111-2. In addition, the second alignment film 114-2 is provided on the second substrate 111-2 so as to cover the third transparent electrode 112-3 and the fourth transparent electrode 112-4.

[0045] The first substrate 111-1 and the second substrate 111-2 are arranged such that the first transparent electrode 112-1 and the second transparent electrode 112-2 on the first substrate 111-1 face the third transparent electrode 112-3 and the fourth transparent electrode 112-4 on the second substrate 111-2. Thus, the extending directions of the first transparent electrode 112-1 and the second transparent electrode 112-2 cross the extending directions of the third transparent electrode 112-3 and the fourth transparent electrode 112-4. Note that the extending directions of the first transparent electrode 112-1 and the second transparent electrode 112-2 can also be orthogonal to the extending directions of the third transparent electrode 112-3 and the fourth transparent electrode 112-4. Further, a sealant 115 is provided at the periphery of each of the first substrate 111-1 and the second substrate 111-2. That is, the first substrate 111-1 and the second substrate 111-2 are bonded by the sealant 115. Further, a liquid crystal is enclosed in a space surrounded by the first substrate 111-1 (more specifically, a first alignment film 114-1), the second substrate 111-2 (more specifically, a second alignment film 114-2), and the sealant 115, and a liquid crystal layer 113 is formed. Note that a spacer or a photo spacer can be dispersed on the first substrate 111-1 or the second substrate 111-2, and the first substrate 111-1 and the second substrate 111-2 can be attached. In this case, the gap of the liquid crystal layer 113 can be maintained by the photo spacer.

[0046] As each of the first substrate 111-1 and the second substrate 111-2, a rigid substrate having light-transmitting properties such as a glass substrate, a quartz substrate, or a sapphire substrate is used, for example. Further, as each of the first substrate 111-1 and the second substrate 111-2, a flexible substrate having light-transmitting properties such as a polyimide resin substrate, an acrylic resin substrate, a silicone resin substrate, or a fluorine resin substrate can be used, for example.

[0047] The first transparent electrode 112-1, the second transparent electrode 112-2, the third transparent electrode 112-3, and the fourth transparent electrode 112-4 each function as an electrode for forming an electric field in the liquid crystal layer 113. As each of the first transparent electrode 112-1, the second transparent electrode 112-2, the third transparent electrode 112-3, and the fourth transparent electrode 112-4, a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) is used, for example.

[0048] The liquid crystal layer 113 can refract the transmitted light or change the polarization state of the transmitted light according to the alignment state of the liquid crystal molecules. As the liquid crystal of the liquid crystal layer 113, for example, a nematic liquid crystal or the like can be used. The liquid crystal is of a positive type in this embodiment, but can be of a negative type by changing the initial alignment direction of the liquid crystal molecules or the like. In addition, it is preferable that the liquid crystal contain a chiral agent that imparts a twist to the liquid crystal molecules.

[0049] The first alignment film 114-1 and the second alignment film 114-2 each align the liquid crystal molecules in the liquid crystal layer 113 in a prescribed direction. The first alignment film 114-1 and the second alignment film 114-2 each can use, for example, a polyimide resin or the like. Note that the first alignment film 114-1 and the second alignment film 114-2 each can be given an alignment property by an orientation treatment such as a rubbing method or a photo-alignment method. The rubbing method is a method of rubbing the surface of the alignment film in one direction. In addition, the photo-alignment method is a method of irradiating the alignment film with linearly polarized ultraviolet rays.

[0050] The sealing material 115 bonds and fixes the first substrate 111-1 and the second substrate 111-2. As the sealing material 115, for example, an epoxy resin adhesive material or an acrylic resin adhesive material or the like can be used. The adhesive material can be of an ultraviolet curing type or a heat curing type.

[0051] The optical element 10 can control the light distribution of non-polarized light by including at least two liquid crystal cells (the first liquid crystal cell 110 and the second liquid crystal cell 120). Thus, it is not necessary to provide a pair of polarizing plates such as those provided on the front and back surfaces of a liquid crystal display element on the outer surfaces of the substrates. In addition, in the first liquid crystal cell 110, different voltages are applied to the first transparent electrode 112-1, the second transparent electrode 112-2, the third transparent electrode 112-3, and the fourth transparent electrode 112-4, respectively, so that the alignment of the liquid crystal of the liquid crystal layer 113 can be controlled. The same applies to the second liquid crystal cell 120.

[0052] [2. Control of alignment of liquid crystal]

[0053] Reference Figure 3A and Figure 3B The alignment of the liquid crystal of the liquid crystal layer 113 is described in detail.

[0054] Figure 3A and Figure 3B are schematic cross-sectional views showing the alignment of the liquid crystal molecules of the liquid crystal layer 113 in the optical element 10 according to an embodiment of the present application. Figure 3A and Figure 3B correspond to a part of the cross-sectional view of the first liquid crystal cell 110 shown in Figure 2A and Figure 2B , respectively.

[0055] As Figure 3A and Figure 3B shown, the first substrate 111-1 and the second substrate 111-2 are attached with an inter-substrate distance d. In addition, the first alignment film 114-1 of the first substrate 111-1 and the second alignment film 114-2 of the second substrate 111-2 are subjected to alignment processing in the x-axis direction and the y-axis direction, respectively. Thus, in the liquid crystal layer 113, the liquid crystal molecules on the first substrate 111-1 side are oriented with their long axes in the x-axis direction in a state where no voltage is applied to the transparent electrodes (in Figure 3A and Figure 3B , the orientation direction of the liquid crystal molecules oriented in the lateral direction of the paper is indicated by an arrow symbol for convenience). That is, the orientation direction of the liquid crystal molecules on the first substrate 111-1 side is orthogonal to the extension direction of the first and second transparent electrodes 112-1 and 112-2. In addition, the liquid crystal molecules on the second substrate 111-2 side are oriented with their long axes in the y-axis direction in a state where no voltage is applied to the transparent electrodes (in Figure 3A and Figure 3B , the orientation direction of the liquid crystal molecules oriented in the normal direction of the paper is indicated by a symbol with a cross in a circle for convenience). That is, the orientation direction of the liquid crystal molecules on the second substrate 111-2 side is orthogonal to the extension direction of the third and fourth transparent electrodes 112-3 and 112-4. Thus, the liquid crystal molecules of the liquid crystal layer 113 are oriented in a state where they are twisted by 90 degrees as they go from the first substrate 111-1 toward the second substrate 111-2 in the z-axis direction. More specifically, in Figure 4A , the liquid crystal molecules on the first substrate 111-1 side are oriented in a state where their long axes are oriented toward the x-axis direction (the lateral direction of the paper) along the orientation direction of the first alignment film 114-1. In addition, the liquid crystal molecules on the second substrate 111-2 side are oriented in a state where their long axes are oriented toward the y-axis direction (the normal direction of the paper) along the orientation direction of the second alignment film 114-2. In addition, the liquid crystal molecules located therebetween gradually change the orientation of their long axes from the x-axis direction to the y-axis direction as they go from the first substrate 111-1 toward the second substrate 111-2.

[0056] Next, the orientation of the liquid crystal of the liquid crystal layer 113 when a voltage is applied will be described in detail with reference to Figure 4A and Figure 4B .

[0057] Figure 4A and Figure 4B are schematic cross-sectional views showing the orientation of the liquid crystal molecules of the liquid crystal layer 113 in the optical element 10 according to the embodiment of the present application when a voltage is applied. In Figure 4A and Figure 4B , the same reference numerals as in Figure 3A and Figure 3BThe orientation directions of the first alignment film 114-1 and the second alignment film 114-2 are illustrated by arrows or symbols with a cross in a circle, as well.

[0058] In Figure 4A and Figure 4B , a low (Low) potential is applied to the first transparent electrode 112-1 and the third transparent electrode 112-3, and a high (High) potential is applied to the second transparent electrode 112-2 and the fourth transparent electrode 112-4 (in Figure 4A and Figure 4B , the symbols of "-" and "+" are used to illustrate the low (Low) potential and the high (High) potential, respectively, for convenience.) That is, a potential difference is generated between the first transparent electrode 112-1 and the second transparent electrode 112-2 and between the third transparent electrode 112-3 and the fourth transparent electrode 112-4. In this case, the liquid crystal molecules on the first substrate 111-1 side are oriented in accordance with the electric field (potential distribution) generated between the first transparent electrode 112-1 and the second transparent electrode 112-2. That is, the long axes of the liquid crystal molecules on the first substrate 111-1 side are oriented in the direction from the first transparent electrode 112-1 toward the second transparent electrode 112-2. Similarly, the liquid crystal molecules on the second substrate 111-2 side are oriented in the direction from the third transparent electrode 112-3 toward the fourth transparent electrode 112-4. Note that hereinafter, the electric field generated between adjacent transparent electrodes on the same substrate will be referred to as a lateral electric field.

[0059] Further, the orientation of the liquid crystal molecules will be described in detail. The liquid crystal molecules on the first substrate 111-1 side are oriented in the x-axis direction in the absence of an electric field, but the orientation of the liquid crystal molecules is the same as the direction of the lateral electric field between the first transparent electrode 112-1 and the second transparent electrode 112-2. Therefore, the liquid crystal molecules located substantially at the center between the first transparent electrode 112-1 and the second transparent electrode 112-2 hardly change their orientation even under the action of the lateral electric field when viewed from above. In addition, the liquid crystal molecules closer to the first transparent electrode 112-1 or the second transparent electrode 112-2 than the center are oriented with a tilt in the z-axis direction in correspondence with the lateral electric field. Therefore, as illustrated in FIG. 6A, the liquid crystal molecules on the first substrate 111-1 side are oriented in the direction from the first transparent electrode 112-1 toward the second transparent electrode 112-2. Figure 4AAs shown, due to the influence of the lateral electric field between the first transparent electrode 112-1 and the second transparent electrode 112-2, the liquid crystal molecules on the first substrate 111-1 side are oriented in a convex circular arc shape from the first transparent electrode 112-1 toward the second transparent electrode 112-2 as a whole between each adjacent transparent electrode as viewed from the first substrate 111-1. Likewise, the liquid crystal molecules on the second substrate 111-2 side are oriented in the y-axis direction, but the orientation of the liquid crystal molecules is the same as the orientation of the lateral electric field between the third transparent electrode 112-3 and the fourth transparent electrode 112-4. Therefore, the liquid crystal molecules located approximately in the center between the third transparent electrode 112-3 and the fourth transparent electrode 112-4 are hardly oriented even under the influence of the lateral electric field. In addition, the liquid crystal molecules closer to the third transparent electrode 112-3 or the fourth transparent electrode 112-4 than the center are oriented with a tilt in the z-axis direction. Therefore, as shown, the light incident on the liquid crystal layer 113 is diffused in accordance with the refractive index distribution of the liquid crystal molecules on the first substrate 111-1 side or the second substrate 111-2 side oriented in a convex circular arc shape. Figure 4B As shown, due to the influence of the lateral electric field between the third transparent electrode 112-3 and the fourth transparent electrode 112-4, the liquid crystal molecules on the second substrate 111-2 side are oriented in a convex circular arc shape from the third transparent electrode 112-3 toward the fourth transparent electrode 112-4 as a whole between each adjacent transparent electrode as viewed from the second substrate 111-2. Thus, the light incident on the liquid crystal layer 113 is diffused in accordance with the refractive index distribution of the liquid crystal molecules on the first substrate 111-1 side or the second substrate 111-2 side oriented in a convex circular arc shape.

[0060] The first substrate 111-1 and the second substrate 111-2 have a sufficiently separated inter-substrate distance d, and therefore the lateral electric field between the first transparent electrode 112-1 and the second transparent electrode 112-2 of the first substrate 111-1 does not affect the orientation of the liquid crystal molecules on the second substrate 111-2 side, or the effect is small enough to be negligible. Likewise, the lateral electric field between the third transparent electrode 112-3 and the fourth transparent electrode 112-4 of the second substrate 111-2 does not affect the orientation of the liquid crystal molecules on the first substrate 111-1 side, or the effect is small enough to be negligible.

[0061] Note that, in the present specification, the liquid crystal layer 113 (or liquid crystal molecules) on the first substrate 111-1 side refers to the liquid crystal layer (or liquid crystal molecules) up to d / 2 from the surface of the first substrate 111-1. Likewise, the liquid crystal layer 113 (or liquid crystal molecules) on the second substrate 111-2 side refers to the liquid crystal layer (or liquid crystal molecules) up to d / 2 from the surface of the second substrate 111-2.

[0062] In the first liquid crystal cell 110, the orientation of the liquid crystal molecules in the liquid crystal layer 113 can be changed by controlling the voltages applied to the first transparent electrode 112-1, the second transparent electrode 112-2, the third transparent electrode 112-3, and the fourth transparent electrode, respectively. As the orientation of the liquid crystal molecules changes, the refractive index distribution of the liquid crystal layer 113 changes. Therefore, the first liquid crystal cell 110 can diffuse transmitted light. The optical element 10 can control the light distribution transmitted through it by utilizing the changes in the refractive index distribution of the liquid crystal layer 113 of the first liquid crystal cell 110 and the liquid crystal layer 123 of the second liquid crystal cell 120.

[0063] [3. Control of light distribution by optical components]

[0064] Reference Figure 5A and Figure 5B The optical element 10 provides a detailed description of its control over the distribution of light.

[0065] Figure 5A and Figure 5B This is a schematic cross-sectional view illustrating the control of light distribution by the optical element 10 according to an embodiment of the present invention. Figure 5A and Figure 5B The optical element 10 shown is Figure 2A The cross-sectional views of the first liquid crystal cell 110 and the second liquid crystal cell 120 shown correspond to a portion of the view. Figure 5A In the optical element 10 shown, no potential is applied to any transparent electrodes. Additionally, in Figure 5B In the optical element 10 shown, a low potential is applied to the first transparent electrode 112-1 and the third transparent electrode 112-3 of the first liquid crystal cell 110, and a high potential is applied to the second transparent electrode 112-2 and the fourth transparent electrode 112-4. Similarly, a low potential is applied to the first transparent electrode 122-1 and the third transparent electrode 122-3 of the second liquid crystal cell 120, and a high potential is applied to the second transparent electrode 122-2 and the fourth transparent electrode 122-4. It should be noted that in Figure 5B For convenience, the symbols “-” and “+” are used to represent low potential and high potential, respectively.

[0066] exist Figure 5A and Figure 5BIn the illustrated optical element 10, the first alignment film 114-1 of the first liquid crystal cell 110 and the first alignment film 124-1 of the second liquid crystal cell 120 are subjected to orientation processing in the x-axis direction. On the other hand, the second alignment film 114-2 of the first liquid crystal cell 110 and the second alignment film 124-2 of the second liquid crystal cell 120 are subjected to orientation processing in the y-axis direction. Thus, in the first liquid crystal cell 110, the orientation direction of the first alignment film 114-1 is the x-axis direction, and the orientation direction of the second alignment film 114-2 is the y-axis direction. Likewise, in the second liquid crystal cell 120, the orientation direction of the first alignment film 124-1 is the x-axis direction, and the orientation direction of the second alignment film 124-2 is the y-axis direction.

[0067] In Figure 5A and Figure 5B , light is incident from a direction perpendicular to the first substrate 111-1 of the first liquid crystal cell 110 and is emitted from the second substrate 121-2 of the second liquid crystal cell 120. The light incident on the first substrate 111-1 of the first liquid crystal cell 110 has a polarization in the x-axis direction (P-polarization component) and a polarization in the y-axis direction (S-polarization component). Therefore, in the following, for convenience, the polarization component in the x-axis direction in the light emitted from the light source is set as a first polarization component 310, and the polarization component in the y-axis direction is set as a second polarization component 320 to describe the process of the light passing through the optical element 10. Figure 5B

[0068] The first polarization component 310 and the second polarization component 320 correspond to the P-polarization component and the S-polarization component of the light emitted from the light source, respectively (see (1) in Figure 5B . Note that, in Figure 5A and Figure 5B , the P-polarization component is illustrated using an arrow (an arrow indicating the horizontal direction of the paper surface), and the S-polarization component is illustrated using a symbol with a cross in a circle (an arrow indicating the normal direction of the paper surface).

[0069] The liquid crystal molecules of the liquid crystal layer 113 on the first substrate 111-1 side of the first liquid crystal cell 110 are oriented with their long axes in the x-axis direction, and thus, as illustrated in Figure 5B , when a transverse electric field is generated between the first transparent electrode 112-1 and the second transparent electrode 112-2, the liquid crystal molecules have a refractive index distribution in the x-axis direction. In addition, the liquid crystal molecules of the liquid crystal layer 113 on the second substrate 111-2 side of the first liquid crystal cell 110 are oriented with their long axes in the y-axis direction, and thus, when a transverse electric field is generated between the third transparent electrode 112-3 and the fourth transparent electrode 112-4, the liquid crystal molecules have a refractive index distribution in the y-axis direction.

[0070] ​Therefore, the first polarization component 310 that has entered the optical element 10 (more specifically, the first liquid crystal cell 110) changes its polarization component according to the twist of the liquid crystal orientation as it goes toward the second substrate 111-2 after entering the first substrate 111-1 (refer to (2) to (4) in FIG. 12). More specifically, the first polarization component 310 has a polarization axis in the x-axis direction on the first substrate 111-1 side, but its polarization axis gradually changes as it passes through the thickness direction of the liquid crystal layer 113 to become a polarization axis in the y-axis direction on the second substrate 111-2 side, and then exits from the second substrate 111-2 side (refer to (5) in FIG. 12). Here, as shown in (1) in FIG. 12, when a lateral electric field is generated between the first transparent electrode 112-1 and the second transparent electrode 112-2, the orientation state of the liquid crystal molecules changes as shown in (2) in FIG. 12, and the refractive index distribution changes. In addition, the first polarization component 310 has its polarization axis parallel to the orientation direction of the liquid crystal molecules of the liquid crystal layer 113 on the first substrate 111-1 side, so it spreads in the x-axis direction according to the change in the refractive index distribution of the liquid crystal molecules. In addition, the first polarization component 310 has its polarization axis changed from the x-axis direction to the y-axis direction within the liquid crystal layer 113, so on the second substrate 111-2 side, its polarization axis is parallel to the orientation direction of the liquid crystal molecules of the liquid crystal layer 113 on the second substrate 111-2 side. Here, as shown in (3) in FIG. 12, when a lateral electric field is generated between the third transparent electrode 112-3 and the fourth transparent electrode 112-4, the orientation state of the liquid crystal molecules changes as shown in (4) in FIG. 12, and the refractive index distribution changes. Therefore, the first polarization component 310 spreads in the y-axis direction according to the change in the refractive index distribution of the liquid crystal molecules. Figure 5B Figure 5B Figure 5B Figure 4A Figure 5B Figure 4B

[0071] In addition, as shown in (1) in FIG. 13, the second polarization component 320 that is an S-polarization component before entering the optical element 10 (more specifically, the first liquid crystal cell 110) changes its polarization component according to the twist of the liquid crystal orientation as it goes toward the second substrate 111-2 after entering the first substrate 111-1 (refer to (2) to (4) in FIG. 13). More specifically, the second polarization component 320 has a polarization axis in the y-axis direction on the first substrate 111-1 side, but its polarization axis gradually changes as it passes through the thickness direction of the liquid crystal layer 113 to become a polarization axis in the x-axis direction on the second substrate 111-2 side, and then exits from the second substrate 111-2 side (refer to (5) in FIG. 13). Here, as shown in (1) in FIG. 13, when a lateral electric field is generated between the first transparent electrode 112-1 and the second transparent electrode 112-2, the orientation state of the liquid crystal molecules changes as shown in (2) in FIG. 13, and the refractive index distribution changes. In addition, the second polarization component 320 has its polarization axis parallel to the orientation direction of the liquid crystal molecules of the liquid crystal layer 113 on the first substrate 111-1 side, so it changes its polarization component to a P-polarization component according to the change in the refractive index distribution of the liquid crystal molecules. In addition, the second polarization component 320 has its polarization axis changed from the y-axis direction to the x-axis direction within the liquid crystal layer 113, so on the second substrate 111-2 side, its polarization axis is parallel to the orientation direction of the liquid crystal molecules of the liquid crystal layer 113 on the second substrate 111-2 side. Here, as shown in (3) in FIG. 13, when a lateral electric field is generated between the third transparent electrode 112-3 and the fourth transparent electrode 112-4, the orientation state of the liquid crystal molecules changes as shown in (4) in FIG. 13, and the refractive index distribution changes. Therefore, the second polarization component 320 spreads in the x-axis direction according to the change in the refractive index distribution of the liquid crystal molecules. Figure 5B Figure 5B Figure 5B ​​​​​​​​In this case, even if a lateral electric field is generated between the first transparent electrode 112-1 and the second transparent electrode 112-2, the second polarized component 320 is orthogonal to the orientation direction of the liquid crystal molecules of the liquid crystal layer 113 on the first substrate 111-1 side, and thus is not affected by the refractive index distribution of the liquid crystal molecules and passes through as it is without being diffused. In addition, the second polarized component 320 changes its polarization axis from the y-axis direction to the x-axis direction within the liquid crystal layer 113, and thus is also orthogonal to the orientation direction of the liquid crystal molecules on the second substrate 111-2 side, and thus is not affected by the refractive index distribution of the liquid crystal molecules and passes through as it is without being diffused.

[0072] That is, the second polarized component 320, which is an S-polarized component before entering the optical element 10, changes its polarization axis from the y-axis direction to the x-axis direction within the first liquid crystal cell 110 to become a P-polarized component, but does not diffuse as the first polarized component 310 does.

[0073] The liquid crystal molecules of the liquid crystal layer 123 of the second liquid crystal cell 120 also have the same refractive index distribution as the liquid crystal molecules of the liquid crystal layer 113 of the first liquid crystal cell 110. Therefore, substantially the same phenomenon as in the first liquid crystal cell 110 also occurs within the second liquid crystal cell 120. On the other hand, the polarization axes of the first polarized component 310 and the second polarized component 320 are exchanged as they pass through the first liquid crystal cell 110, and thus the polarization components affected by the refractive index distribution of the liquid crystal molecules of the liquid crystal layer 113 are also exchanged. That is, as shown in FIG. 5, even if a lateral electric field is generated between the first transparent electrode 122-1 and the second transparent electrode 122-2 and between the third transparent electrode 122-3 and the fourth transparent electrode 112-4 of the second liquid crystal cell 120, the first polarized component 310 passing through the second liquid crystal cell 120 changes its polarization axis from the y-axis direction to the x-axis direction again (see (6) to (8) in FIG. 5), but does not diffuse. On the other hand, the second polarized component 320 passing through the second liquid crystal cell 120 changes its polarization axis from the x-axis direction to the y-axis direction again (see (6) to (8) in FIG. 5) and is affected by the refractive index distribution of the liquid crystal molecules of the liquid crystal layer 123 and diffuses. Figure 5B Figure 5B Figure 5B

[0074] As described above, in the optical element 10, the polarization direction of light entering the optical element 10 is changed twice by stacking two liquid crystal cells (the first liquid crystal cell 110 and the second liquid crystal cell 120), and as a result, the polarization direction before entering and after entering can be made constant (see FIG. 6). Figure 5B ​​​(1) and (9) in the above). On the other hand, the optical element 10 can change the refractive index distribution of the liquid crystal molecules in the liquid crystal layer of the liquid crystal cell, and can refract the transmitted light. More specifically, the first liquid crystal cell 110 diffuses the light of the first polarization component 310 (P polarization component) in the x-axis direction, the y-axis direction, or both the x-axis and the y-axis, and the second liquid crystal cell 120 diffuses the light of the second polarization component 320 (S polarization component) in the x-axis direction, the y-axis direction, or both the x-axis and the y-axis. Therefore, in the case of diffusing light without changing the polarization state of unpolarized light, it is preferable that the number of layers of the optical element 10 is even.

[0075] In addition, the above mainly uses Figure 5A This explains the process by which various polarization components diffuse and the polarization axis changes as they pass through the optical element 10. Figure 5B The optical element 10 is in a state where no potential is applied to each transparent electrode (a state where there is no potential difference between adjacent transparent electrodes), except that it does not cause the polarization component to diffuse. Figure 5A Similarly, optical elements cause a change in the polarization axis of the polarization component. To avoid repetition, regarding the use of... Figure 5B Description and labeling of the polarization components of optical elements. Figure 5A The same reference numerals (1) to (9) are used, and their descriptions are omitted.

[0076] It should be noted that, as Figure 5B and Figure 6 As shown, an optical elastic resin layer 130 is disposed between the first liquid crystal cell 110 and the second liquid crystal cell 120. Light is also refracted at the interface between the second substrate 111-2 of the first liquid crystal cell 110 and the optical elastic resin layer 130, or at the interface between the first substrate 121-1 of the second liquid crystal cell 120 and the optical elastic resin layer 130. Therefore, the refractive index of the optical elastic resin in the optical elastic resin layer 130 is preferably close to the refractive index of the second substrate 111-2 of the first liquid crystal cell 110 and the first substrate 121-1 of the second liquid crystal cell 120. In addition, since the optical element 10 is disposed close to the light source, its temperature may rise due to heat from the light source. In this case, in order to mitigate the effect of thermal expansion of the optical elastic resin in the optical elastic resin layer 130, the thickness of the optical elastic resin layer 130 is preferably greater than the inter-substrate distance d between the first substrate 111-1 and the second substrate 111-2 of the first liquid crystal cell 110 or between the first substrate 121-1 and the second substrate 121-2 of the second liquid crystal cell 120.

[0077] The optical element 10 can control the light distribution of transmitted light by applying a potential to each transparent electrode. That is, the optical element 10 can form a predetermined light distribution pattern. Here, as an example, refer to... Figure 6An optical element 10 using two liquid crystal cells (a first liquid crystal cell 110 and a second liquid crystal cell 120) is described below.

[0078] Figure 6 is a timing chart showing the potential applied to each transparent electrode included in the optical element 10 according to an embodiment of the present application. Note that, Figure 6 the reference numerals (V 11 ) of the potentials described below are shown in Table 1.

[0079] [Table 1]

[0080]

[0081] In the following, for the sake of convenience, the potential applied to each transparent electrode is described as a first potential (a variable potential, for example, 0 V for a low potential and 30 V for a high potential), a second potential (a variable potential, for example, 0 V for a low potential and 30 V for a high potential) having a phase opposite to that of the first potential, and a third potential (an intermediate potential, for example, 15 V). The third potential is a potential between the low potential and the high potential, and can be a fixed potential or a variable potential. Note that the values of the voltages are not limited to Figure 4A 0 V, 15 V, and 30 V described below.

[0082] In the first liquid crystal cell 110, the first transparent electrode 112-1 and the second transparent electrode 112-2 are applied with the first potential and the second potential, respectively. In addition, the third transparent electrode 112-3 and the fourth transparent electrode 112-4 are each applied with the third potential. The phase of the first potential applied to the first transparent electrode 112-1 is opposite to that of the second potential applied to the second transparent electrode 112-2. Thus, a potential difference (for example, +30 V or -30 V) is generated between the first transparent electrode 112-1 and the second transparent electrode 112-2. In contrast, the third transparent electrode 112-3 and the fourth transparent electrode 112-4 on the second substrate 111-2 side are in a state of no potential. In addition, the third transparent electrode 112-3 and the fourth transparent electrode 112-4 on the second substrate 111-2 side are in a state of +15 V or -15 V with respect to the first transparent electrode 112-1 or the second transparent electrode 112-2 on the first substrate 111-1 side, and there is no bias in the potential difference between the transparent electrode on one side of the first substrate 111-1 and the transparent electrode on the other side in terms of absolute value.

[0083] Thus, the liquid crystal molecules on the first substrate 111-1 side change the orientation state in accordance with the potential difference between the first transparent electrode 112-1 and the second transparent electrode 112-2 (see FIG. 2B). In addition, the liquid crystal molecules on the second substrate 111-2 side change the orientation state in accordance with the potential difference between the third transparent electrode 112-3 and the fourth transparent electrode 112-4 (see FIG. 2C). Figure 4B and Figure 4AOn the other hand, since no potential difference is generated between the third transparent electrode 112-3 and the fourth transparent electrode 112-4, and further, the first substrate 111-1 and the second substrate 111-2 are sufficiently separated to the extent that the potential on the first substrate 111-1 side does not affect, the liquid crystal molecules on the second substrate 111-2 side do not change the alignment direction from the initial alignment direction. Further, the third potential applied to the third transparent electrode 112-3 and the fourth transparent electrode 112-4 is an intermediate potential between the first potential and the second potential, and thus even if the low potential and the high potential are alternately applied to the first transparent electrode 112-1 and the second transparent electrode 112-2, no capacitance is accumulated, and the alignment state of the liquid crystal molecules on the second substrate 111-2 side does not change.

[0084] In the second liquid crystal cell 120, the first potential and the second potential are applied to the first transparent electrode 122-1 and the second transparent electrode 122-2, respectively. Further, the third potential is applied to each of the third transparent electrode 122-3 and the fourth transparent electrode 122-4. The first potential applied to the first transparent electrode 122-1 and the second potential applied to the second transparent electrode 122-2 are opposite in phase. Thus, a potential difference (for example, +30 V or -30 V) is generated between the first transparent electrode 122-1 and the second transparent electrode 122-2. In contrast to this, the third transparent electrode 122-3 and the fourth transparent electrode 122-4 on the second substrate 121-2 side become a state of no potential. Further, the third transparent electrode 122-3 and the fourth transparent electrode 122-4 on the second substrate 121-2 side generate +15 V or -15 V in either state between the first transparent electrode 122-1 on the first substrate 121-1 side or between the second transparent electrode 122-2, and in the case of looking at the absolute value, the potential difference between the transparent electrode on one side of the first substrate 121-1 side and the transparent electrode on the other side is not biased.

[0085] Thus, the liquid crystal molecules on the first substrate 121-1 side change the alignment state in accordance with the potential difference between the first transparent electrode 122-1 and the second transparent electrode 122-2 (refer to FIG. 6B). On the other hand, the liquid crystal molecules on the second substrate 121-2 side do not change the alignment direction from the initial alignment direction, and the alignment state is maintained. Figure 4B and Figure 6On the other hand, since no potential difference is generated between the third transparent electrode 122-3 and the fourth transparent electrode 122-4, and in addition, the first substrate 121-1 and the second substrate 121-2 are sufficiently separated to the extent that the potential on the first substrate 121-1 side does not affect, the liquid crystal molecules on the second substrate 121-2 side do not change the alignment direction from the initial alignment direction. In addition, the third potential applied to the third transparent electrode 122-3 and the fourth transparent electrode 122-4 is an intermediate potential between the first potential and the second potential, and thus even if the low potential and the high potential are alternately applied to the first transparent electrode 122-1 and the second transparent electrode 122-2, no capacitance is accumulated, and the alignment state of the liquid crystal molecules on the second substrate 121-2 side does not change.

[0086] In addition, as shown in FIG. 6, the potential variation of the first transparent electrode 112-1 and the second transparent electrode 112-2 of the first liquid crystal cell 110 is synchronized with the potential variation of the first transparent electrode 122-1 and the second transparent electrode 122-2 of the second liquid crystal cell 120, respectively. Figure 6

[0087] In the case where the above-described potential is applied to each transparent electrode, the liquid crystal molecules of the liquid crystal layer 113 on the first substrate 111-1 side of the first liquid crystal cell 110 refract light having a polarization in the x-axis direction to the x-axis direction. Therefore, the first liquid crystal cell 110 diffuses light having a polarization in the x-axis direction to the x-axis direction.

[0088] In addition, the liquid crystal molecules of the liquid crystal layer 123 on the first substrate 121-1 side of the second liquid crystal cell 120 also refract light having a polarization in the x-axis direction to the x-axis direction. Therefore, the second liquid crystal cell 120 also diffuses light having a polarization in the x-axis direction to the x-axis direction.

[0089] That is, when the potential of each transparent electrode is the potential shown in FIG. 6, in the optical element 10, if light is incident from the first substrate 111-1 side of the first liquid crystal cell 110 (as shown in FIG. 7A), the light is refracted to the x-axis direction by the liquid crystal molecules of the liquid crystal layer 113 on the first substrate 111-1 side of the first liquid crystal cell 110. Figure 5A Figure 5B Figure 7 ​​​indicates that light is irradiated toward the first substrate 111-1 from the lower side of the first liquid crystal cell 110. In this case, the first polarization component 310 having a polarization axis in the x-axis direction is diffused in the x-axis direction on the first substrate 111-1 side while changing the polarization axis to the y-axis direction during passing through the first liquid crystal cell 110. On the other hand, the second polarization component 320 having a polarization in the y-axis direction changes the polarization axis from the y-axis direction to the x-axis direction without diffusion. Then, these polarization components are injected into the second liquid crystal cell 120 as they are. The second polarization component 320 changing the polarization axis from the y-axis direction to the x-axis direction without diffusion in the first liquid crystal cell 110 is diffused in the x-axis direction during passing through the second liquid crystal cell 120, and then changes the polarization axis to the y-axis direction. On the other hand, the first polarization component 310 changing the polarization axis from the x-axis direction to the y-axis direction while diffusing in the first liquid crystal cell 110 changes the polarization axis from the y-axis direction to the x-axis direction without diffusion. In this way, light injected into the optical element 10 is diffused in the x-axis direction during passing through the first liquid crystal cell 110 or the second liquid crystal cell 120. Thus, light transmitted through the optical element 10 can form a light distribution pattern spread in the x-axis direction.

[0090] The distribution of the light distribution of the indicating light can be controlled by the magnitude of the voltage applied to the transparent electrode. For example, when the voltage applied to the transparent electrode is increased, the light distribution angle becomes large, and light is further diffused. In addition, the light distribution angle can also be controlled by the distance d between the substrates or the pitch p between the adjacent transparent electrodes, for example.

[0091] [4. Correlation between the distance between the substrates and the pitch]

[0092] Reference Signs Figure 7 The correlation between the distance d between the substrates and the pitch p is described in detail.

[0093] Figures 3A-4B is a graph showing the front surface relative luminance (relative luminance (luminance) at 0 degrees) with respect to d / p in the liquid crystal cell of the optical element 10 according to the embodiment of the present application. As shown in the graph, the relative luminance at 0 degrees is the highest when d / p is 1.0, and the relative luminance at 0 degrees is the lowest when d / p is 0.5 or 2.0. Figure 7The inter-substrate distance d is the distance between the first substrate 111-1 and the second substrate 111-2 of the first liquid crystal cell 110 (or the distance between the first substrate 121-1 and the second substrate 121-2 of the second liquid crystal cell 120). Further, the pitch p is the distance between the centers of two adjacent transparent electrodes on the first substrate 111-1 (or the first substrate 121-1) or the second substrate 111-2 (or the second substrate 121-2). Further, the front surface relative luminance is the luminance of light emitted in the vertical direction (0 degrees) from the second substrate 111-2 from among light emitted from the first substrate 111-1 (or the first substrate 121-1) and light emitted from the second substrate 111-2 (or the second substrate 121-2). Figure 7 The graph shown normalizes the luminance of light in the case where there is no optical element 10 (only a light source) to 1. Thus, Figure 7 The y-axis of the graph shown can also be said to be the relative luminance ratio in the case where the luminance in the case where there is no optical element 10 is set to 1.

[0094] Note that the data shown in the graph were obtained Figure 7 The liquid crystal cell of the data shown in the graph has the first transparent electrode 112-1 and the second transparent electrode 112-2 formed on the first substrate 111-1, but does not have the third transparent electrode 112-3 and the fourth transparent electrode 112-4 formed on the second substrate 111-2. Further, when the luminance was measured, a low potential (0 V) was applied to the first transparent electrode 112-1, and a high potential (30 V) was applied to the second transparent electrode 112-2.

[0095] As Figure 8 As shown, as d / p becomes larger, the front surface relative luminance decreases, but the proportion of decrease in the front surface relative luminance is greatly different between the case where d / p < 1 and the case where d / p > 1. In the case where d / p < 1, although the front surface relative luminance greatly decreases as it approaches d / p = 1, the front surface luminance was measured to be about 0.2 to 0.4. This indicates a decrease in luminance due to diffusion of light by the liquid crystal cell, but also indicates that the diffusion is not sufficient. In contrast, in the case where d / p > 1, the front surface relative luminance becomes 0.1 or less, and thereafter, even if d / p is increased, the front surface relative luminance is stable. This indicates that diffusion of light by the liquid crystal cell is sufficient in the case where d / p > 1. That is, in the case where d / p > 1, excellent diffusion of light is obtained. Thus, in the optical element 10, it is preferable that the inter-substrate distance d and the pitch p satisfy d / p > 1, and it is further preferable that d / p > 2 be satisfied.

[0096] Further, the transparent electrode material has a high refractive index, which sometimes affects the transmittance of the liquid crystal cell. Therefore, the width of the transparent electrode is preferably small. That is, the electrode distance b between the two adjacent transparent electrodes is preferably equal to or smaller than the width a of the transparent electrode. For example, if the electrode distance b is expressed in relation to the pitch p, it is preferable that p / 2 ≤ b is satisfied.

[0097] As explained above, the optical element 10 according to the present embodiment can control the light distribution of the light transmitted through the optical element 10 by controlling the voltage applied to each transparent electrode. However, in the case where each transparent electrode simply extends in a straight line, moire fringes due to interference of light or coloring due to wavelength dependence of the refractive index can occur. Therefore, the optical element 10 according to the present embodiment has a shape and a configuration of the transparent electrode that can reduce moire fringes or coloring.

[0098] [5. Shape and configuration of transparent electrode]

[0099] Figure 8 is a schematic view illustrating the shape and the configuration of the first transparent electrode 112-1 and the second transparent electrode 112-2 of the first liquid crystal cell 110 of the optical element 10 according to an embodiment of the present application.

[0100] As illustrated in Figure 8 , the first transparent electrode 112-1 and the second transparent electrode 112-2 on the first substrate 111-1 of the first liquid crystal cell 110 are alternately arranged in the x-axis direction, and each of the first transparent electrode 112-1 and the second transparent electrode 112-2 is provided so as to extend in the y-axis direction. The first transparent electrode 112-1 is provided in a straight line shape in the y-axis direction. In contrast, the second transparent electrode 112-2 is provided in a kana shape having a first bent portion 116-1 bent toward the x-axis direction. That is, the second transparent electrode 112-2 includes a straight portion having a prescribed angle with respect to the extension direction (y-axis direction) of the first transparent electrode 112-1 and the first bent portion 116-1 connecting the straight portion. Note that the prescribed angle is 0 degrees or more and 4 degrees or less, which is very small. Therefore, the side edge of the first transparent electrode 112-1 is perpendicular to the orientation direction (y-axis direction) of the first alignment film 114-1, whereas the side edge of the second transparent electrode 112-2 is inclined to the orientation direction of the first alignment film 114-1 by the prescribed angle. Further, in the case where the width (distance between long sides) of the straight portion of the second transparent electrode 112-2 provided so as to have an angle with respect to the y-axis direction is a1, although the length of the second transparent electrode 112-2 in the x-axis direction is slightly larger than a1, the length of the straight portion in the x-axis direction can be regarded as a1. Thus, hereinafter, for convenience, the length of the second transparent electrode 112-2 in the x-axis direction is assumed to be a1.

[0101] In addition, the extension direction of the electrode in the following text refers to the direction parallel to the extension direction of the electrode that extends in a straight line. More specifically, it is the y-axis direction on the first substrate 111-1 side and the x-axis direction on the second substrate 111-2 side.

[0102] Two second transparent electrodes 112-2 adjacent to the first transparent electrode 112-1 are arranged symmetrically about the extending direction of the first transparent electrode 112-1. Therefore, as... Figure 8 As shown, the first buckled portions 116-1 of the left-hand second transparent electrode 112-2 and the middle second transparent electrode 112-2 are located at the farthest point when viewed from the middle first transparent electrode 112-1. Conversely, the first buckled portions 116-1 of the middle second transparent electrode 112-2 and the right-hand second transparent electrode 112-2 are located at the closest point when viewed from the right first transparent electrode 112-1. Figure 8 In the shape and configuration of the transparent electrodes shown, the pitch between the first transparent electrode 112-1 and the second transparent electrode 112-2, and the inter-electrode distance between them, gradually change in the y-axis direction. Furthermore, the electric field formed between adjacent first transparent electrodes 112-1 and second transparent electrodes 112-2 due to the tilt of the second transparent electrode 112-2 relative to the y-axis direction also subtly changes in the y-axis direction. Therefore, it is possible to reduce moiré fringes caused by light interference and wavelength-dependent coloration.

[0103] The first transparent electrode 112-1 and the second transparent electrode 112-2 have a first maximum pitch p1 and a first maximum inter-electrode distance b1 at the first buckling portion 116-1. That is, p1 = a1 + b1. As described above, the orientation of light, i.e., the beam angle, can also be controlled by the inter-substrate distance d and the pitch p. Figure 8 In the shape and arrangement of the transparent electrodes shown, it is preferable to satisfy d / p1≥1, and more preferably to satisfy d / p1≥2. Furthermore, in the relationship between the first maximum pitch p1 and the first maximum distance b1 between the electrodes, it is preferable to satisfy p1 / 2≤b1. By satisfying these conditions, the first liquid crystal cell 110 can control the voltage applied to the first transparent electrode 112-1 and the second transparent electrode 112-2, thereby ensuring sufficient diffusion of transmitted light.

[0104] It should be noted that, in Figure 9 In this configuration, the first buckling portion 116-1 is configured to be provided only at point 1 in the length direction (y-axis direction) of the second transparent electrode 112-2, but it is also possible to provide multiple first buckling portions 116-1 in the length direction.

[0105] Figure 9is a schematic view illustrating the shapes and configurations of the first transparent electrode 112-1, the second transparent electrode 112-2, the third transparent electrode 112-3, and the fourth transparent electrode of the first liquid crystal cell 110 of the optical element 10 according to the embodiment of the present application.

[0106] The third transparent electrode 112-3 and the fourth transparent electrode 112-4 on the second substrate 111-2 of the first liquid crystal cell 110 have the same shapes and configurations as the first transparent electrode 112-1 and the second transparent electrode 112-2 after being rotated by 90 degrees. That is, the third transparent electrode 112-3 and the fourth transparent electrode 112-4 are alternately arranged in the y-axis direction, and each of the third transparent electrode 112-3 and the fourth transparent electrode 112-4 is arranged so as to extend in the x-axis direction. The third transparent electrode 112-3 is arranged in a straight line shape in the x-axis direction. In contrast, the fourth transparent electrode 112-4 is arranged in a kana shape having a second bent portion 116-2 bent toward the y-axis direction. In addition, two fourth transparent electrodes 112-4 adjacent to the third transparent electrode 112-3 are arranged symmetrically with the extension direction of the third transparent electrode 112-3 as an axis. Thus, in the optical element 10 according to the embodiment of the present application, the pitch and the electrode distance in each transparent electrode are changed, and thus the occurrence of Moire fringes and coloring can be reduced.

[0107] The third transparent electrode 112-3 and the fourth transparent electrode 112-4 have a second maximum pitch p2 and a second maximum electrode distance b2 at the second bent portion 116-2. The width of each of the third transparent electrode 112-3 and the fourth transparent electrode 112-4 is a2, and p2 = a2 + b2 is satisfied. In addition, the first maximum pitch p1 and the second maximum pitch p2 satisfy p1 > p2. Figure 10 In the shapes and configurations of the transparent electrodes shown, it is also preferable that d / p2≥1 be satisfied, and it is further preferable that d / p2≥2 be satisfied. In addition, in the relationship between the second maximum pitch p2 and the second maximum electrode distance b2, it is preferable that p2 / 2≤b2 be satisfied. By satisfying these conditions, the first liquid crystal cell 110 can control the voltage applied to the third transparent electrode 112-3 and the fourth transparent electrode 112-4, and can sufficiently diffuse the transmitted light.

[0108] As described above, the optical element 10 according to the embodiment of the present application can control the voltage applied to each transparent electrode and control the light distribution of the transmitted light. In addition, in the optical element 10 according to the embodiment of the present application, the pitch and the electrode distance in each transparent electrode are changed, and thus the occurrence of Moire fringes and coloring can be reduced.

[0109] <Second Embodiment>

[0110] Reference Signs List Figure 10The shapes and configurations of the first transparent electrode 112A-1 and the second transparent electrode 112A-2, which differ from those of the first transparent electrode 112-1 and the second transparent electrode 112-2 described in the first embodiment, will be described.

[0111] Figure 10 This is a schematic diagram illustrating the shape and arrangement of the first transparent electrode 112A-1 and the second transparent electrode 112A-2 of the first liquid crystal cell 110 of the optical element 10 according to an embodiment of the present invention. It should be noted that, hereinafter, when the configuration of the first transparent electrode 112A-1 and the second transparent electrode 112A-2 is the same as that described in the first embodiment, its description may sometimes be omitted.

[0112] like Figure 10 As shown, the first transparent electrode 112A-1 and the second transparent electrode 112A-2 are alternately arranged in the x-axis direction, and each of the first transparent electrode 112A-1 and the second transparent electrode 112A-2 is arranged to extend in the y-axis direction. The first transparent electrode 112A-1 is configured as a straight line in the y-axis direction. In contrast, the second transparent electrode 112A-2 is configured as a curved shape with a bend in the x-axis direction. That is, the second transparent electrode 112A-2 includes a curved portion that bends relative to the extending direction (y-axis direction) of the first transparent electrode 112A-1 and a first top 116A-1 whose orientation changes in the curved portion in the x-axis direction. It should be noted that the two second transparent electrodes 112A-2 adjacent to the first transparent electrode 112A-1 are arranged symmetrically about the extending direction of the first transparent electrode 112A-1. Therefore, the side edge of the first transparent electrode 112A-1 is perpendicular to the orientation direction (y-axis direction) of the first alignment film 114-1, while the side edge of the second transparent electrode 112-2 is bent relative to the orientation direction of the first alignment film 114-1.

[0113] The first transparent electrode 112A-1 and the second transparent electrode 112A-2 have a first maximum pitch p1 and a first maximum inter-electrode distance b1 at the first top 116A-1. The widths of the first transparent electrode 112A-1 and the second transparent electrode 112A-2 are each a1, satisfying p1 = a1 + b2. Figure 11 In the shape and arrangement of the transparent electrodes shown, it is preferable to satisfy d / p1≥1, and more preferably to satisfy d / p1≥2. Furthermore, in the relationship between the first maximum pitch p1 and the first maximum distance b1 between the electrodes, it is preferable to satisfy p1 / 2≤b1. By satisfying these conditions, the first liquid crystal cell 110 can control the voltage applied to the first transparent electrode 112A-1 and the second transparent electrode 112A-2, thereby ensuring sufficient diffusion of transmitted light.

[0114] As explained above, the optical element 10 according to the present embodiment is capable of controlling the voltage applied to each transparent electrode and controlling the light distribution of the transmitted light. In addition, in the optical element 10 according to the present embodiment, the pitch and the inter-electrode distance in each transparent electrode gradually change in the y-axis direction, and the electric field formed between the adjacent first transparent electrode 112-1 and the second transparent electrode 112-2 due to the bending of the second transparent electrode 112-2 with respect to the y-axis direction also subtly changes in the y-axis direction. Therefore, it is possible to reduce the occurrence of moire fringes and coloration.

[0115] THIRD EMBODIMENT

[0116] REFERENCE Figure 11 The shape and configuration of the first transparent electrode 112B-1 and the second transparent electrode 112B-2, which are different from the shape and configuration of the transparent electrodes explained in the first embodiment and the second embodiment, will be explained.

[0117] Figure 11 FIG. 7 is a schematic view illustrating the shape and configuration of the first transparent electrode 112B-1 and the second transparent electrode 112B-2 of the first liquid crystal cell 110 of the optical element 10 according to an embodiment of the present application. Note that, hereafter, when the configuration of the first transparent electrode 112B-1 and the second transparent electrode 112B-2 is the same as the configuration of the first transparent electrode 112-1 and the second transparent electrode 112-2 explained in the first embodiment, the explanation thereof will be omitted at times.

[0118] As Figure 11 illustrated in FIG. 7, the first transparent electrode 112B-1 and the second transparent electrode 112B-2 are alternately arranged in the x-axis direction, and each of the first transparent electrode 112B-1 and the second transparent electrode 112B-2 is provided in a manner extending in the y-axis direction. The first transparent electrode 112B-1 is provided in a linear shape in the y-axis direction. In contrast, the second transparent electrode 112B-2 is provided in a kana shape having a first bent portion 116B-1 bent toward the x-axis direction. Therefore, in the optical element 10 according to the present embodiment, too, the pitch and the inter-electrode distance in each transparent electrode change, and thus it is possible to reduce the occurrence of moire fringes and coloration.

[0119] In addition, in the Figure 11In the shape and configuration of the transparent electrodes shown, the two second transparent electrodes 112B-2 adjacent to the first transparent electrode 112B-1 are disposed asymmetrically with the extension direction of the first transparent electrode 112B-1 as the axis. Specifically, the first bent portions 116B-1 of the two second transparent electrodes 112B-2 adjacent to the first transparent electrode 112B-1 are disposed at different positions. Thus, the symmetry of the configuration of the transparent electrodes can be reduced, and thus the occurrence of Moire fringes or coloring can be further reduced.

[0120] The first transparent electrode 112B-1 and the second transparent electrodes 112B-2 have a first maximum pitch pi and a first maximum inter-electrode distance bi at the first bent portion 116B-1. The width of each of the first transparent electrode 112B-1 and the second transparent electrodes 112B-2 is ai, and pi = ai + b2 is satisfied. In the shape and configuration of the transparent electrodes shown, the first maximum pitch pi and the first maximum inter-electrode distance bi satisfy pi / 2 < bi. Figure 12 In the shape and configuration of the transparent electrodes shown, it is also preferable that d / pi ≥ 1 be satisfied, and it is further preferable that d / pi ≥ 2 be satisfied. In addition, in the relationship between the first maximum pitch pi and the first maximum inter-electrode distance bi, it is preferable that pi / 2 ≤ bi be satisfied. By satisfying these conditions, the first liquid crystal cell 110 of the optical element 10 according to the present embodiment can control the voltage applied to the first transparent electrode 112B-1 and the second transparent electrodes 112B-2, and cause the transmitted light to be sufficiently diffused.

[0121] As described above, the optical element 10 according to the present embodiment can control the voltage applied to each transparent electrode and control the light distribution of the transmitted light. In addition, in the optical element 10 according to the present embodiment, since the pitch and the inter-electrode distance in each transparent electrode vary, the occurrence of Moire fringes and coloring can be reduced.

[0122] <Fourth Embodiment>

[0123] Reference Signs Figure 12 The shape and configuration of the first transparent electrode 112C-1 and the second transparent electrodes 112C-2 of the first liquid crystal cell 110 of the optical element 10 according to an embodiment of the present application will be described.

[0124] Figure 12 is a schematic view illustrating the shape and configuration of the first transparent electrode 112C-1 and the second transparent electrodes 112C-2 of the first liquid crystal cell 110 of the optical element 10 according to an embodiment of the present application. Note that hereinafter, when the configuration of the first transparent electrode 112C-1 and the second transparent electrodes 112C-2 is the same as that of the first transparent electrode 112-1 and the second transparent electrodes 112-2 described in the first embodiment, the description thereof will be omitted at times.

[0125] As Figure 12As shown, the first transparent electrodes 112C-1 and the second transparent electrodes 112C-2 are alternately arranged in the x-axis direction, and each of the first transparent electrodes 112C-1 and the second transparent electrodes 112C-2 is provided in a manner extending in the y-axis direction. The first transparent electrodes 112C-1 are provided in a linear shape in the y-axis direction. In contrast, the second transparent electrodes 112C-2 are provided in a zigzag shape including a plurality of first curved portions 116C-1 curved in the x-axis direction. Thus, in the optical element 10 according to the present embodiment, the pitch and the electrode-to-electrode distance in each transparent electrode are varied, and thus the occurrence of Moire fringes and coloring can be reduced.

[0126] In addition, in the shape and arrangement of the transparent electrodes shown in FIG. 12, the two second transparent electrodes 112C-2 adjacent to the first transparent electrode 112C-1 are asymmetrically arranged with the extension direction of the first transparent electrode 112C-1 as an axis. Specifically, the two second transparent electrodes 112C-2 adjacent to the first transparent electrode 112C-1 each have a different number of the first curved portions 116C-1. Thus, the symmetry of the arrangement of the transparent electrodes can be reduced, and thus the occurrence of Moire fringes or coloring can be further reduced. Figure 12 In the shape and arrangement of the transparent electrodes shown in FIG. 12, the two second transparent electrodes 112C-2 adjacent to the first transparent electrode 112C-1 are asymmetrically arranged with the extension direction of the first transparent electrode 112C-1 as an axis. Specifically, the two second transparent electrodes 112C-2 adjacent to the first transparent electrode 112C-1 each have a different number of the first curved portions 116C-1. Thus, the symmetry of the arrangement of the transparent electrodes can be reduced, and thus the occurrence of Moire fringes or coloring can be further reduced.

[0127] The first transparent electrodes 112C-1 and the second transparent electrodes 112C-2 have a first maximum pitch p1 and a first maximum electrode-to-electrode distance b1 at one of the plurality of first curved portions 116C-1. The width of each of the first transparent electrodes 112C-1 and the second transparent electrodes 112C-2 is a1, and p1 = a1 + b1 is satisfied. In the shape and arrangement of the transparent electrodes shown in FIG. 12, the first maximum pitch p1 and the first maximum electrode-to-electrode distance b1 are preferably related to each other as p1 / 2 ≤ b1. Figure 13 In the shape and arrangement of the transparent electrodes shown in FIG. 12, it is also preferable that d / p1 ≥ 1 be satisfied, and it is further preferable that d / p1 ≥ 2 be satisfied. In addition, in the relationship between the first maximum pitch p1 and the first maximum electrode-to-electrode distance b1, it is preferable that p1 / 2 ≤ b1 be satisfied. By satisfying these conditions, the first liquid crystal cell 110 of the optical element 10 according to the present embodiment can control the voltage applied to the first transparent electrodes 112B-1 and the second transparent electrodes 112B-2 to sufficiently diffuse the transmitted light.

[0128] As described above, the optical element 10 according to the present embodiment can control the voltage applied to each transparent electrode and control the light distribution of the transmitted light. In addition, in the optical element 10 according to the present embodiment, the pitch and the electrode-to-electrode distance in each transparent electrode are varied, and thus the occurrence of Moire fringes and coloring can be reduced.

[0129] < Fifth Embodiment >

[0130] Referring to FIG. 13, the optical element 10 according to the present embodiment includes a first liquid crystal cell 110, a second liquid crystal cell 120, and a third liquid crystal cell 130. The first liquid crystal cell 110, the second liquid crystal cell 120, and the third liquid crystal cell 130 are arranged in this order from the light source 100 side. Figure 13The shape and configuration of the first and second transparent electrodes 112D-1 and 112D-2 different from those of the transparent electrodes explained in the first to fourth embodiments will be explained.

[0131] Figure 13 Fig. 11 is a schematic view illustrating the shape and configuration of the first and second transparent electrodes 112D-1 and 112D-2 of the first liquid crystal cell 110 of the optical element 10 according to an embodiment of the present application. Note that, hereafter, when the configuration of the first and second transparent electrodes 112D-1 and 112D-2 is the same as that of the first and second transparent electrodes 112-1 and 112-2 explained in the first embodiment, the explanation thereof will be omitted at times.

[0132] As shown in Fig. 11, the first and second transparent electrodes 112D-1 and 112D-2 are alternately arranged in the x-axis direction, and each of the first and second transparent electrodes 112D-1 and 112D-2 is arranged so as to extend in the y-axis direction. The first transparent electrode 112D-1 is arranged in a straight line shape in the y-axis direction. In contrast, the second transparent electrode 112D-2 is arranged in a zigzag shape including a plurality of first curved portions 116D-1 curved in the x-axis direction. Thus, in the optical element 10 according to the present embodiment, the pitch and the inter-electrode distance in each of the transparent electrodes are varied, and thus the occurrence of moire and coloring can be reduced. Figure 13

[0133] In addition, in the shape and configuration of the transparent electrodes shown in Fig. 11, two second transparent electrodes 112D-2 adjacent to the first transparent electrode 112D-1 are arranged asymmetrically with the extension direction of the first transparent electrode 112D-1 as the axis. Specifically, the positions of the first curved portions 116D-1 of the second transparent electrodes 112D-2 are randomly arranged. Thus, the symmetry of the arrangement of the transparent electrodes can be reduced, and thus the occurrence of moire or coloring can be further reduced. Here, the positions of the first curved portions 116D-1 in the second transparent electrodes 112D-2 are randomly arranged means that, in each of the second transparent electrodes 112D-2, the number, the positions of the first curved portions 116D-1, and the positions between the first curved portions 116D-1 and the first transparent electrode 112D-1 adjacent thereto are different, and in other words, means that the shape of each of the second transparent electrodes 112D-2 is different. Note that, in this case, it is preferable that the shapes of the plurality of second transparent electrodes 112D-2 on the first substrate 111-1 are all different, but a group in which the shapes are different can be repeatedly arranged in a plurality of rows adjacent to each other. The same applies to the fourth transparent electrode 112D-4. Figure 13

[0134] ​​In the case where the first bend 116D-1 is formed randomly, the minimum electrode-to-electrode distance b between the first transparent electrode 112D-1 and the second transparent electrode 112D-2 s The minimum electrode-to-electrode distance b can be set to a prescribed set value. For example, the minimum electrode-to-electrode distance b s The minimum electrode-to-electrode distance b can be a value set by the user or a value determined in accordance with the precision of photolithography or the like.

[0135] The first transparent electrode 112D-1 and the second transparent electrode 112D-2 have a first maximum pitch pi and a first maximum electrode-to-electrode distance bi at one of the plurality of first bends 116D-1. The width of each of the first transparent electrode 112D-1 and the second transparent electrode 112D-2 is ai, and pi = ai + bi is satisfied. In Figure 13 In the shape and configuration of the transparent electrodes illustrated, it is also preferable that di / pi ≥ 1 be satisfied, and it is further preferable that di / pi ≥ 2 be satisfied. However, in the shape and configuration of the transparent electrodes illustrated, it is preferable that ai + bi < pi ≤ di be satisfied. Figure 13 In the shape and configuration of the transparent electrodes illustrated, the minimum electrode-to-electrode distance b s is set, and it is necessary that pi > ai + bi s be satisfied. Therefore, in the shape and configuration of the transparent electrodes illustrated, it is preferable that ai + bi s < pi ≤ di, and it is further preferable that ai + bi s < pi ≤ di / 2 be satisfied. Figure 14

[0136] In addition, in the relationship between the first maximum pitch pi and the first maximum electrode-to-electrode distance bi, it is preferable that pi / 2 ≤ bi be satisfied. By satisfying these conditions, the first liquid crystal cell 110 of the optical element 10 according to the present embodiment is able to control the voltage applied to the first transparent electrode 112D-1 and the second transparent electrode 112D-2 and cause the transmitted light to sufficiently spread.

[0137] As described above, the optical element 10 according to the present embodiment is able to control the voltage applied to each transparent electrode and control the light distribution of the transmitted light. In addition, in the optical element 10 according to the present embodiment, since the pitch and the electrode-to-electrode distance in each transparent electrode vary, it is possible to reduce the occurrence of moire fringes and coloring.

[0138] < Sixth Embodiment >

[0139] Reference will be made to Figure 14 The configuration of the transparent electrodes in the stack of the first liquid crystal cell 110 and the second liquid crystal cell 120 will be described.

[0140] Figure 14 ​is a schematic view of the configuration in the lamination of the first transparent electrode 112-1 and the second transparent electrode 112-2 of the first liquid crystal cell 110 and the first transparent electrode 122-1 and the second transparent electrode 122-2 of the second liquid crystal cell 120, which is related to the optical element 10 of an embodiment of the present application.

[0141] In ​ , the first liquid crystal cell 110 and the second liquid crystal cell 120 are not laminated so that the positions of the transparent electrodes in plan view coincide. That is, the first liquid crystal cell 110 and the second liquid crystal cell 120 are laminated so as to have an angle α between the extension direction of the first transparent electrode 112-1 of the first liquid crystal cell 110 and the extension direction of the first transparent electrode 122-1 of the second liquid crystal cell 120. The angle α is, for example, 0 degrees or more and 4 degrees or less. By staggering the extension direction of the transparent electrode of the first liquid crystal cell 110 and the extension direction of the transparent electrode of the second liquid crystal cell 120, the symmetry between the liquid crystal cells can also be reduced. Thus, the occurrence of Moire fringes and coloring can be reduced. Note that it is preferable that the first meandering portion of the first transparent electrode 112-1 of the first liquid crystal cell 110 and the first meandering portion of the first transparent electrode 112-1 of the second liquid crystal cell 120 do not overlap. The same applies to the second meandering portion. The symmetry between the liquid crystal cells can be further reduced, and the occurrence of Moire fringes and coloring can be further reduced.

[0142] As explained above, the optical element 10 related to the present embodiment can control the voltage applied to each transparent electrode and control the light distribution of the transmitted light. In addition, in the optical element 10 related to the present embodiment, the pitch and the inter-electrode distance in each transparent electrode also vary in the lamination direction of the liquid crystal cells, and thus the occurrence of Moire fringes and coloring can be further reduced.

[0143] Various changes and modifications are conceivable to those skilled in the art within the scope of the idea of the present application, and it should be understood that such changes and modifications also belong to the scope of the present application. For example, for each of the above-described embodiments, a scheme obtained by appropriately adding, deleting, or changing the design of a constituent element, or a scheme obtained by adding, omitting, or changing a condition of a process, as long as the spirit of the present application is possessed, is also included in the scope of the present application.

[0144] In addition, as for other effects brought about by the schemes in the present embodiment, it can be explained that the effects explicitly described from the description of the present specification, or the effects that can be appropriately thought of by those skilled in the art are of course brought about by the present application.

[0145] Explanation of Reference Signs

[0146] 10: optical element, 110: first liquid crystal cell, 111-1: first substrate, 111-2: second substrate, 112-1, 112A-1, 112B-1, 112C-1, 112D-1: first transparent electrode, 112-2, 112A-2, 112B-2, 112C-2, 112D-2: second transparent electrode, 112-3: third transparent electrode, 112-4: fourth transparent electrode, 113: liquid crystal layer, 114-1: first alignment film, 114-2: second alignment film, 115: sealing material, 116-1, 116B-1, 116C-1, 116D-1: first bent portion, 116A-1: first top portion, 116-2: second bent portion, 120: second liquid crystal cell, 121-1: first substrate, 121-2: second substrate, 122-1: first transparent electrode, 122-2: second transparent electrode, 122-3: third transparent electrode, 122-4: fourth transparent electrode, 123: liquid crystal layer, 124-1: first alignment film, 124-2: second alignment film, 125: sealing material, 130: optically elastic resin layer, 310: first polarization component, 320: second polarization component.

Claims

1. An optical element comprising at least two stacked liquid crystal cells, Each of the at least two liquid crystal cells includes: A first substrate has a first transparent electrode and a second transparent electrode alternately disposed in a first direction; A second substrate has a third transparent electrode and a fourth transparent electrode alternately disposed in a second direction intersecting the first direction; and The liquid crystal layer between the first substrate and the second substrate The second transparent electrode includes a first buckled portion that buckles in the first direction. The fourth transparent electrode includes a second buckled portion that buckles in the second direction. The at least two liquid crystal units include a first liquid crystal unit and a second liquid crystal unit. The first buckled portion of the first liquid crystal cell does not overlap with the first buckled portion of the second liquid crystal cell. The second buckled portion of the first liquid crystal cell does not overlap with the second buckled portion of the second liquid crystal cell.

2. The optical element according to claim 1, wherein, The second direction is orthogonal to the first direction.

3. The optical element according to claim 1 or 2, wherein, The second transparent electrode has a く shape.

4. The optical element according to claim 1 or 2, wherein, A pair of second transparent electrodes adjacent to the first transparent electrode are arranged symmetrically with respect to the extension direction of the first transparent electrode.

5. The optical element according to claim 1 or 2, wherein, A pair of second transparent electrodes adjacent to the first transparent electrode are arranged asymmetrically with respect to the extension direction of the first transparent electrode.

6. The optical element according to claim 1 or 2, wherein, The number of the first buckling portions of a pair of second transparent electrodes adjacent to the first transparent electrode is different.

7. The optical element according to claim 1 or 2, wherein, The substrate distance d between the first substrate and the second substrate and the first maximum pitch p1 between the first transparent electrode and the second transparent electrode satisfy d / p1≥1.

8. The optical element according to claim 7, wherein, The optical element satisfies d / p1≥2.

9. The optical element according to claim 7, wherein, The first maximum pitch p1 and the first maximum inter-electrode distance b1 between the first transparent electrode and the second transparent electrode satisfy p1 / 2≤b1.

10. The optical element according to claim 7, wherein, The distance d between the substrates and the second maximum pitch p2 between the third transparent electrode and the fourth transparent electrode satisfy d / p2≥1.

11. The optical element according to claim 10, wherein, The optical element satisfies d / p²≥2.

12. The optical element according to claim 10, wherein, The second maximum pitch p2 and the second maximum inter-electrode distance b2 between the third transparent electrode and the fourth transparent electrode satisfy p2 / 2≤b2.

13. The optical element according to claim 1 or 2, wherein, The shapes of the multiple second transparent electrodes are different from each other. The first maximum pitch p1 between the first transparent electrode and the second transparent electrode, the substrate distance d between the first substrate and the second substrate, the width a1 of the first transparent electrode and the second transparent electrode respectively, and the minimum electrode distance b between the first transparent electrode and the second transparent electrode. s Satisfy a1+b s <p1≤d.

14. The optical element according to claim 13, wherein, The optical element satisfies a1+b s <p1≤d / 2.

15. The optical element according to claim 13, wherein, The first maximum pitch p1 and the first maximum inter-electrode distance b1 between the first transparent electrode and the second transparent electrode satisfy p1 / 2≤b1.

16. The optical element according to claim 13, wherein, The shapes of the multiple fourth transparent electrodes are different. The second maximum pitch p2 between the third transparent electrode and the fourth transparent electrode, the substrate distance d, the width a2 of each of the third and fourth transparent electrodes, and the minimum electrode distance b. s Satisfy a2+b s <p2≤d.

17. The optical element according to claim 16, wherein, The optical element satisfies a² + b s <p2≤d / 2.

18. The optical element according to claim 16, wherein, The second maximum pitch p2 and the second maximum inter-electrode distance b2 between the third transparent electrode and the fourth transparent electrode satisfy p2 / 2≤b2.

19. The optical element according to claim 1 or 2, wherein, The angle α formed by the extension direction of the first transparent electrode of the first liquid crystal unit and the extension direction of the first transparent electrode of the second liquid crystal unit is greater than 0 degrees and less than 4 degrees.

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