Optical Elements

Abstract

To provide an optical element having an anisotropic shape and capable of controlling light distribution.SOLUTION: The optical element includes first to fourth liquid crystal cells which are sequentially stacked. Each of the first to fourth liquid crystal cells includes a first substrate on which a pair of first inter-digital transparent electrodes are arranged, and a second substrate on which a pair of second inter-digital transparent electrodes are arranged. The extension direction of the pair of first inter-digital transparent electrodes intersects the extension direction of the pair of second inter-digital transparent electrodes. Between two different liquid crystal cells of the first to fourth liquid crystal cells, one of the pair of first inter-digital transparent electrodes of one liquid crystal cell is electrically connected to one of the pair of second inter-digital transparent electrodes of the other liquid crystal cell.SELECTED DRAWING: Figure 2A

Description

[Technical field]

[0001] An embodiment of the present invention relates to an optical element that controls the distribution of light emitted from a light source. [Background technology]

[0002] Conventionally, optical elements that utilize the change in refractive index of liquid crystals by adjusting the voltage applied to the liquid crystal, so-called liquid crystal lenses, have been known (see, for example, Patent Document 1, Patent Document 2, or Patent Document 3). For example, the lighting devices described in Patent Document 1 and Patent Document 2 use liquid crystal lenses to distribute light from a light source in a circular shape. Also, in the beam shaping device described in Patent Document 3, the pattern of electrodes applied to the liquid crystal is changed to change the shape of the light distribution. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-317879 A [Patent Document 2] JP 2010-230887 A [Patent Document 3] JP 2014-160277 A Summary of the Invention [Problem to be solved by the invention]

[0004] It is desirable to be able to control not only an isotropic shape but also an anisotropic shape of the light distribution, and in particular, it is desirable to be able to control a light distribution having an elliptical shape.

[0005] In view of the above problems, an object of one embodiment of the present invention is to provide an optical element capable of controlling light distribution having an anisotropic shape. [Means for solving the problem]

[0006] An optical element according to an embodiment of the present invention includes a first liquid crystal cell, a second liquid crystal cell on the first liquid crystal cell, a third liquid crystal cell on the second liquid crystal cell, and a fourth liquid crystal cell on the third liquid crystal cell, the first liquid crystal cell including a first substrate on which a first transparent electrode and a second transparent electrode are alternately arranged in a comb-like shape in a first direction, and a second substrate on which a third transparent electrode and a fourth transparent electrode are alternately arranged in a comb-like shape in a second direction intersecting the first direction. The second liquid crystal cell includes a third substrate adjacent to the second substrate, on which a fifth transparent electrode and a sixth transparent electrode are alternately arranged in a comb-like shape in the first direction, and a fourth substrate on which a seventh transparent electrode and an eighth transparent electrode are alternately arranged in a comb-like shape in the second direction, and the third liquid crystal cell includes a fifth substrate adjacent to the fourth substrate, on which a ninth transparent electrode and a tenth transparent electrode are alternately arranged in a comb-like shape in the second direction, and an eleventh transparent electrode and an eighth transparent electrode are alternately arranged in the first direction. the fourth liquid crystal cell includes a seventh substrate adjacent to the sixth substrate, on which a thirteenth transparent electrode and a fourteenth transparent electrode are alternately arranged in a comb-like shape in the second direction, and an eighth substrate on which a fifteenth transparent electrode and a sixteenth transparent electrode are alternately arranged in a comb-like shape in the first direction, the first transparent electrode and the fifteenth transparent electrode being electrically connected to each other, and the second transparent electrode and the sixteenth transparent electrode being alternately arranged in a comb-like shape in the first direction. are electrically connected to each other, the third transparent electrode and the thirteenth transparent electrode are electrically connected to each other, the fourth transparent electrode and the fourteenth transparent electrode are electrically connected to each other, the fifth transparent electrode and the eleventh transparent electrode are electrically connected to each other, the sixth transparent electrode and the twelfth transparent electrode are electrically connected to each other, the seventh transparent electrode and the ninth transparent electrode are electrically connected to each other, and the eighth transparent electrode and the tenth transparent electrode are electrically connected to each other. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic perspective view of an optical element according to one embodiment of the present invention. [Figure 2A] 1 is a schematic cross-sectional view of an optical element according to one embodiment of the present invention. [Figure 2B]1 is a schematic cross-sectional view of an optical element according to one embodiment of the present invention. [Figure 3A] 1A to 1C are schematic cross-sectional views illustrating control of light distribution by an optical element according to an embodiment of the present invention. [Figure 3B] 1A to 1C are schematic cross-sectional views illustrating control of light distribution by an optical element according to an embodiment of the present invention. [Figure 4] FIG. 2 is a schematic diagram illustrating connections of transparent electrodes of an optical element according to one embodiment of the present invention. [Figure 5A] 4 is a timing chart showing a potential supplied to a transparent electrode of an optical element according to an embodiment of the present invention. [Figure 5B] 4 is a timing chart showing a potential supplied to a transparent electrode of an optical element according to an embodiment of the present invention. [Figure 5C] 4 is a measurement result of the azimuth angle of light transmitted through an optical element according to an embodiment of the present invention. [Figure 6A] 4 is a timing chart showing a potential supplied to a transparent electrode of an optical element according to an embodiment of the present invention. [Figure 6B] 4 is a measurement result of the azimuth angle of light transmitted through an optical element according to an embodiment of the present invention. [Figure 7A] 4 is a timing chart showing a potential supplied to a transparent electrode of an optical element according to an embodiment of the present invention. [Figure 7B] 4 is a timing chart showing a potential supplied to a transparent electrode of an optical element according to an embodiment of the present invention. [Figure 7C] 4 is a measurement result of the azimuth angle of light transmitted through an optical element according to an embodiment of the present invention. [Figure 8A] 4 is a timing chart showing a potential supplied to a transparent electrode of an optical element according to an embodiment of the present invention. [Figure 8B] 4 is a measurement result of the azimuth angle of light transmitted through an optical element according to an embodiment of the present invention. [Figure 9A] 4 is a timing chart showing a potential supplied to a transparent electrode of an optical element according to an embodiment of the present invention. [Figure 9B] 4 is a timing chart showing a potential supplied to a transparent electrode of an optical element according to an embodiment of the present invention. [Figure 9C] 9C is a schematic diagram showing the shape of light distribution when the potential of the timing chart shown in FIG. 9A or FIG. 9B is supplied to a transparent electrode in an optical element according to one embodiment of the present invention. FIG. [Figure 10A] 4 is a timing chart showing a potential supplied to a transparent electrode of an optical element according to an embodiment of the present invention. [Figure 10B] 4 is a timing chart showing a potential supplied to a transparent electrode of an optical element according to an embodiment of the present invention. [Figure 10C] 10C is a schematic diagram showing the shape of light distribution when the potential of the timing chart shown in FIG. 10A or FIG. 10B is supplied to a transparent electrode in an optical element according to one embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, each embodiment of the present invention will be described with reference to the drawings, etc. However, the present invention can be embodied in various forms without departing from the gist of the technical idea thereof, and should not be interpreted as being limited to the description of the embodiments exemplified below.

[0009] In order to clarify the description, the drawings may show the width, thickness, shape, etc. of each part in a schematic manner compared to the actual embodiment, but these are merely examples, and the illustrated shapes themselves do not limit the interpretation of the present invention. In addition, in the drawings, elements having the same functions as those explained in the drawings already shown in the specification may be given the same reference numerals even in different drawings, and duplicate explanations may be omitted.

[0010] When a film is processed to form multiple structures, each structure may have a different function or role, and each structure may be formed on a different base. However, these multiple structures are derived from a film formed as the same layer in the same process, and have the same material. Therefore, these multiple films are defined as existing in the same layer.

[0011] When expressing an aspect in which a structure is placed on top of another structure, the term "above" is used, unless otherwise specified, to include both a case in which another structure is placed directly above, in contact with, a structure, and a case in which another structure is placed above, via yet another structure.

[0012] An optical element 10 according to one embodiment of the present invention will be described with reference to FIGS. 1 to 8B.

[0013] [1. Configuration of optical elements] FIG. 1 is a schematic perspective view of an optical element 10 according to an embodiment of the present invention. As shown in FIG. 1, the optical element 10 includes a first liquid crystal cell 110-1, a second liquid crystal cell 110-2, a third liquid crystal cell 110-3, and a fourth liquid crystal cell 110-4. The first liquid crystal cell 110-1, the second liquid crystal cell 110-2, the third liquid crystal cell 110-3, and the fourth liquid crystal cell 110-4 are stacked in the z-axis direction. The second liquid crystal cell 110-2 is provided on the first liquid crystal cell 110-1. The third liquid crystal cell 110-3 is provided on the second liquid crystal cell 110-2. The fourth liquid crystal cell 110-4 is provided on the third liquid crystal cell 110-3. Although not shown, a light source is disposed below the first liquid crystal cell 110-1. Therefore, light emitted from the light source is transmitted through the first liquid crystal cell 110-1, the second liquid crystal cell 110-2, the third liquid crystal cell 110-3, and the fourth liquid crystal cell 110-4 in this order.

[0014] The first optical elastic resin layer 170-1 bonds and fixes the first liquid crystal cell 110-1 and the second liquid crystal cell 110-2. The second optical elastic resin layer 170-2 bonds and fixes the second liquid crystal cell 110-2 and the third liquid crystal cell 110-3. The third optical elastic resin layer 170-3 bonds and fixes the third liquid crystal cell 110-3 and the fourth liquid crystal cell 110-4. An adhesive containing an acrylic resin or an epoxy resin having light transmission can be used for each of the first optical elastic resin layer 170-1, the second optical elastic resin layer 170-2, and the third optical elastic resin layer 170-3.

[0015] Figures 2A and 2B are schematic cross-sectional views of an optical element 10 according to one embodiment of the present invention. Specifically, Figure 2A is a schematic cross-sectional view in a zx plane cut along line A1-A2 shown in Figure 1, and Figure 2B is a schematic cross-sectional view in a yz plane cut along line B1-B2 shown in Figure 1. In the following, the x-axis direction and the y-axis direction may be referred to as a first direction and a second direction, respectively.

[0016] The first liquid crystal cell 110-1 includes a first substrate 120-1 on which a first transparent electrode 130-1 and a second transparent electrode 130-2 are formed, and a second substrate 120-2 on which a third transparent electrode 130-3 and a fourth transparent electrode 130-4 are formed. A first alignment film 140-1 that covers the first transparent electrode 130-1 and the second transparent electrode 130-2 is formed on the first substrate 120-1. A second alignment film 140-2 that covers the third transparent electrode 130-3 and the fourth transparent electrode 130-4 is formed on the second substrate 120-2. The first substrate 120-1 and the second substrate 120-2 are disposed such that the first transparent electrode 130-1 and the second transparent electrode 130-2 on the first substrate 120-1 face the third transparent electrode 130-3 and the fourth transparent electrode 130-4 on the second substrate 120-2. A first seal material 150-1 is formed on the periphery of each of the first substrate 120-1 and the second substrate 120-2. That is, the first substrate 120-1 and the second substrate 120-2 are bonded together via the first seal material 150-1. Furthermore, liquid crystal is sealed in the space surrounded by the first substrate 120-1 (more specifically, the first alignment film 140-1), the second substrate 120-2 (more specifically, the second alignment film 140-2), and the first sealing material 150-1, forming a first liquid crystal layer 160-1.

[0017] The second liquid crystal cell 110-2 includes a third substrate 120-3 on which a fifth transparent electrode 130-5 and a sixth transparent electrode 130-6 are formed, and a fourth substrate 120-4 on which a seventh transparent electrode 130-7 and an eighth transparent electrode 130-8 are formed. A third alignment film 140-3 is formed on the third substrate 120-3 to cover the fifth transparent electrode 130-5 and the sixth transparent electrode 130-6. A fourth alignment film 140-4 is formed on the fourth substrate 120-4 to cover the seventh transparent electrode 130-7 and the eighth transparent electrode 130-8. The third substrate 120-3 and the fourth substrate 120-4 are disposed such that the fifth transparent electrode 130-5 and the sixth transparent electrode 130-6 on the third substrate 120-3 face the seventh transparent electrode 130-7 and the eighth transparent electrode 130-8 on the fourth substrate 120-4. In addition, a second seal material 150-2 is formed on the periphery of each of the third substrate 120-3 and the fourth substrate 120-4. That is, the third substrate 120-3 and the fourth substrate 120-4 are bonded via the second seal material 150-2. Furthermore, liquid crystal is sealed in the space surrounded by the third substrate 120-3 (more specifically, the third alignment film 140-3), the fourth substrate 120-4 (more specifically, the fourth alignment film 140-4), and the second sealing material 150-2, forming a second liquid crystal layer 160-2.

[0018] The third liquid crystal cell 110-3 includes a fifth substrate 120-5 on which a ninth transparent electrode 130-9 and a tenth transparent electrode 130-10 are formed, and a sixth substrate 120-6 on which an eleventh transparent electrode 130-11 and a twelfth transparent electrode 130-12 are formed. A fifth alignment film 140-5 that covers the ninth transparent electrode 130-9 and the tenth transparent electrode 130-10 is formed on the fifth substrate 120-5. In addition, a sixth alignment film 140-6 that covers the eleventh transparent electrode 130-11 and the twelfth transparent electrode 130-12 is formed on the sixth substrate 120-6. The fifth substrate 120-5 and the sixth substrate 120-6 are arranged such that the ninth transparent electrode 130-9 and the tenth transparent electrode 130-10 on the fifth substrate 120-5 face the eleventh transparent electrode 130-11 and the twelfth transparent electrode 130-12 on the sixth substrate 120-6. In addition, a third sealant 150-3 is formed on the periphery of each of the fifth substrate 120-5 and the sixth substrate 120-6. That is, the fifth substrate 120-5 and the sixth substrate 120-6 are bonded via the third sealant 150-3. In addition, liquid crystal is sealed in the space surrounded by the fifth substrate 120-5 (more specifically, the fifth alignment film 140-5), the sixth substrate 120-6 (more specifically, the sixth alignment film 140-6), and the third sealing material 150-3, forming a third liquid crystal layer 160-3.

[0019] The fourth liquid crystal cell 110-4 includes a seventh substrate 120-7 on which a thirteenth transparent electrode 130-13 and a fourteenth transparent electrode 130-14 are formed, and an eighth substrate 120-8 on which a fifteenth transparent electrode 130-15 and a sixteenth transparent electrode 130-16 are formed. A seventh alignment film 140-7 that covers the thirteenth transparent electrode 130-13 and the fourteenth transparent electrode 130-14 is formed on the seventh substrate 120-7. In addition, an eighth alignment film 140-8 that covers the fifteenth transparent electrode 130-15 and the sixteenth transparent electrode 130-16 is formed on the eighth substrate 120-8. The seventh substrate 120-7 and the eighth substrate 120-8 are arranged such that the thirteenth transparent electrode 130-13 and the fourteenth transparent electrode 130-14 on the seventh substrate 120-7 face the fifteenth transparent electrode 130-15 and the sixteenth transparent electrode 130-16 on the eighth substrate 120-8. In addition, a fourth sealant 150-4 is formed on the periphery of each of the seventh substrate 120-7 and the eighth substrate 120-8. That is, the seventh substrate 120-7 and the eighth substrate 120-8 are bonded via the fourth sealant 150-4. In addition, liquid crystal is sealed in the space surrounded by the seventh substrate 120-7 (more specifically, the seventh alignment film 140-7), the eighth substrate 120-8 (more specifically, the eighth alignment film 140-8), and the fourth sealing material 150-4, forming a fourth liquid crystal layer 160-4.

[0020] The first liquid crystal cell 110-1, the second liquid crystal cell 110-2, the third liquid crystal cell 110-3, and the fourth liquid crystal cell 110-4 have the same basic configuration, except for the arrangement of the transparent electrodes 130.

[0021] In the first liquid crystal cell 110-1, the first transparent electrode 130-1 and the second transparent electrode 130-2 extend in the y-axis direction, and the third transparent electrode 130-3 and the fourth transparent electrode 130-4 extend in the x-axis direction. The first transparent electrode 130-1 and the second transparent electrode 130-2 are arranged alternately in a comb-like manner in the x-axis direction, and the third transparent electrode 130-3 and the fourth transparent electrode 130-4 are arranged alternately in a comb-like manner in the y-axis direction. In a plan view, the extension direction (y-axis direction) of the first transparent electrode 130-1 and the second transparent electrode 130-2 is perpendicular to the extension direction (x-axis direction) of the third transparent electrode 130-3 and the fourth transparent electrode 130-4, but may be slightly shifted and intersect with each other.

[0022] In the second liquid crystal cell 110-2, the fifth transparent electrode 130-5 and the sixth transparent electrode 130-6 extend in the y-axis direction, and the seventh transparent electrode 130-7 and the eighth transparent electrode 130-8 extend in the x-axis direction. The fifth transparent electrode 130-5 and the sixth transparent electrode 130-6 are arranged alternately in a comb-like manner in the x-axis direction, and the seventh transparent electrode 130-7 and the eighth transparent electrode 130-8 are arranged alternately in a comb-like manner in the y-axis direction. In a plan view, the extension direction (y-axis direction) of the fifth transparent electrode 130-5 and the sixth transparent electrode 130-6 is perpendicular to the extension direction (x-axis direction) of the seventh transparent electrode 130-7 and the eighth transparent electrode 130-8, but may be slightly shifted from each other and intersect.

[0023] In the third liquid crystal cell 110-3, the ninth transparent electrode 130-9 and the tenth transparent electrode 130-10 extend in the x-axis direction, and the eleventh transparent electrode 130-11 and the twelfth transparent electrode 130-12 extend in the y-axis direction. The ninth transparent electrode 130-9 and the tenth transparent electrode 130-10 are alternately arranged in a comb-like manner in the y-axis direction, and the eleventh transparent electrode 130-11 and the twelfth transparent electrode 130-12 are alternately arranged in a comb-like manner in the x-axis direction. In a plan view, the extension direction (x-axis direction) of the ninth transparent electrode 130-9 and the tenth transparent electrode 130-10 is perpendicular to the extension direction (y-axis direction) of the eleventh transparent electrode 130-11 and the twelfth transparent electrode 130-12, but may be slightly shifted from each other and intersect.

[0024] In the fourth liquid crystal cell 110-4, the thirteenth transparent electrode 130-13 and the fourteenth transparent electrode 130-14 extend in the x-axis direction, and the fifteenth transparent electrode 130-15 and the sixteenth transparent electrode 130-16 extend in the y-axis direction. The thirteenth transparent electrode 130-13 and the fourteenth transparent electrode 130-14 are alternately arranged in a comb-like manner in the y-axis direction, and the fifteenth transparent electrode 130-15 and the sixteenth transparent electrode 130-16 are alternately arranged in a comb-like manner in the x-axis direction. In a plan view, the extension direction (x-axis direction) of the thirteenth transparent electrode 130-13 and the fourteenth transparent electrode 130-14 is perpendicular to the extension direction (y-axis direction) of the fifteenth transparent electrode 130-15 and the sixteenth transparent electrode 130-16, but may be slightly shifted from each other and intersect.

[0025] In a plan view, the first transparent electrode 130-1 of the first liquid crystal cell 110-1, the fifth transparent electrode 130-5 of the second liquid crystal cell 110-2, the eleventh transparent electrode 130-11 of the third liquid crystal cell 110-3, and the fifteenth transparent electrode 130-15 of the fourth liquid crystal cell 110-4 are overlapped such that their extending directions (y-axis direction) are substantially aligned with each other. However, the first liquid crystal cell 110-1 to the fourth liquid crystal cell 110-4 may be arranged such that the first transparent electrode 130-1, the fifth transparent electrode 130-5, the eleventh transparent electrode 130-11, and the fifteenth transparent electrode 130-15 are slightly misaligned when overlapping.

[0026] Each of the first substrate 120-1 to the eighth substrate 120-8 may be a rigid substrate having light-transmitting properties, such as a glass substrate, a quartz substrate, a sapphire substrate, etc. Each of the first substrate 120-1 to the eighth substrate 120-8 may be a flexible substrate having light-transmitting properties, such as a polyimide resin substrate, an acrylic resin substrate, a siloxane resin substrate, a fluororesin substrate, etc.

[0027] Each of the first transparent electrode 130-1 to the sixteenth transparent electrode 130-16 functions as an electrode for forming an electric field in the liquid crystal layer 160. Each of the first transparent electrode 130-1 to the sixteenth transparent electrode 130-16 is made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

[0028] Each of the first liquid crystal layer 160-1 to the fourth liquid crystal layer 160-4 can refract the light passing therethrough or change the polarization state of the light passing therethrough depending on the alignment state of the liquid crystal molecules. Nematic liquid crystal or the like is used as the liquid crystal for each of the first liquid crystal layer 160-1 to the fourth liquid crystal layer 160-4. The liquid crystal described in this embodiment is of the positive type, but it is also possible to apply a negative type by changing the initial alignment direction of the liquid crystal molecules. In addition, the liquid crystal preferably contains a chiral agent that imparts a twist to the liquid crystal molecules.

[0029] Each of the first alignment film 140-1 to the eighth alignment film 140-8 aligns liquid crystal molecules in the liquid crystal layer 160 in a predetermined direction. Each of the first alignment film 140-1 to the eighth alignment film 140-8 is made of a material such as polyimide resin. Each of the first alignment film 140-1 to the eighth alignment film 140-8 may be given an alignment characteristic by an alignment treatment such as a rubbing method or a photo-alignment method. The rubbing method is a method in which the surface of the alignment film is rubbed in one direction. The photo-alignment method is a method in which the alignment film is irradiated with linearly polarized ultraviolet light.

[0030] Each of the first seal material 150-1 to the fourth seal material 150-4 is made of an adhesive material containing an epoxy resin or an acrylic resin, etc. The adhesive material may be an ultraviolet curing type or a thermosetting type.

[0031] The optical element 10 can control the distribution of unpolarized light by including at least two liquid crystal cells (for example, the first liquid crystal cell 110-1 and the second liquid crystal cell 110-2). Therefore, 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 surfaces of the first substrate 120-1 of the first liquid crystal cell 110-1 and the eighth substrate 120-8 of the fourth liquid crystal cell 110-4.

[0032] [2. Control of light distribution by optical element 10] 3A and 3B are schematic cross-sectional views for explaining the control of light distribution by the optical element 10 according to one embodiment of the present invention. Parts of the cross-sectional views of the first liquid crystal cell 110-1 and the second liquid crystal cell 110-2 shown in FIG. 2A are shown in FIG. 3A. The optical element 10 is shown in a state where no potential is applied to the transparent electrode 130, and FIG. 3B is shown in a state where a potential is applied to the transparent electrode 130.

[0033] The first alignment film 140-1 is aligned in the x-axis direction. Therefore, as shown in FIG. 3A, the liquid crystal molecules on the first substrate 120-1 side of the first liquid crystal layer 160-1 are aligned with their major axes along the x-axis direction. That is, the alignment direction of the liquid crystal molecules on the first substrate 120-1 side is perpendicular to the extension direction (y-axis direction) of the first transparent electrode 130-1 and the second transparent electrode 130-2. Also, the second alignment film 140-2 is aligned in the y-axis direction. Therefore, as shown in FIG. 3A, the liquid crystal molecules on the second substrate 120-2 side of the first liquid crystal layer 160-1 are aligned with their major axes along the y-axis direction. That is, the alignment direction of the liquid crystal molecules on the second substrate 120-2 side is perpendicular to the extension direction (x-axis direction) of the third transparent electrode 130-3 and the fourth transparent electrode 130-4. Therefore, the liquid crystal molecules in first liquid crystal layer 160-1 gradually change the direction of their major axes from the x-axis direction to the y-axis direction as they move from first substrate 120-1 to second substrate 120-2, and are aligned in a 90-degree twisted state.

[0034] The liquid crystal molecules of the second liquid crystal layer 160-2 are similar to those of the first liquid crystal layer 160-1, and therefore a description thereof will be omitted here.

[0035] When a potential is applied to the transparent electrode 130, the orientation of the liquid crystal molecules changes as shown in FIG. 3B. Here, it is assumed that a low potential is applied to the first transparent electrode 130-1, the third transparent electrode 130-3, the fifth transparent electrode 130-5, and the seventh transparent electrode 130-7, and a high potential is applied to the second transparent electrode 130-2, the fourth transparent electrode 130-4, the sixth transparent electrode 130-6, and the eighth transparent electrode 130-8. For convenience, in FIG. 3B, the low potential and the high potential are illustrated using the symbols "-" and "+", respectively. In the following, the electric field generated between adjacent transparent electrodes may be referred to as a transverse electric field.

[0036] As shown in FIG. 3B, due to the influence of the transverse electric field between the first transparent electrode 130-1 and the second transparent electrode 130-2, the liquid crystal molecules on the first substrate 120-1 are generally aligned in a convex arc shape along the x-axis direction with respect to the first substrate 120-1. Similarly, due to the influence of the transverse electric field between the third transparent electrode 130-3 and the fourth transparent electrode 130-4, the liquid crystal molecules on the second substrate 120-2 are generally aligned in a convex arc shape along the y-axis direction with respect to the second substrate 120-2. The alignment of the liquid crystal molecules located approximately in the center between the first transparent electrode 130-1 and the second transparent electrode 130-2 is hardly changed by any of the transverse electric fields. Therefore, light incident on the first liquid crystal layer 160-1 is diffused in the x-axis direction in accordance with the refractive index distribution of the liquid crystal molecules oriented in a convex arc shape along the x-axis direction on the first substrate 120-1 side, and is diffused in the y-axis direction in accordance with the refractive index distribution of the liquid crystal molecules oriented in a convex arc shape along the y-axis direction on the second substrate 120-2 side.

[0037] Since the first substrate 120-1 and the second substrate 120-2 are sufficiently separated from each other, the horizontal electric field between the first transparent electrode 130-1 and the second transparent electrode 130-2 of the first substrate 120-1 does not affect the alignment of the liquid crystal molecules on the second substrate 120-2 side, or is negligibly small. Similarly, the horizontal electric field between the third transparent electrode 130-3 and the fourth transparent electrode 130-4 of the second substrate 120-2 does not affect the alignment of the liquid crystal molecules on the first substrate 120-1 side, or is negligibly small.

[0038] The liquid crystal molecules in the second liquid crystal layer 160-2 when a potential is applied to the fifth transparent electrode 130-5 to the eighth transparent electrode 130-8 are similar to the liquid crystal molecules in the first liquid crystal layer 160-1, and therefore a description thereof will be omitted here.

[0039] Next, the light distribution of the light transmitted through the optical element 10 will be described. The light emitted from the light source has a polarized component in the x-axis direction (P polarized component) and a polarized component in the y-axis direction (S polarized component), but for convenience, the light will be divided into a P polarized component and an S polarized component that are orthogonal to each other in the following description. That is, the light emitted from the light source (see (1) in Figures 3A and 3B) includes a first polarized light 310 having a P polarized component and a second polarized light 320 having an S polarized component. Note that the arrow symbol and the circle with a cross in Figures 3A and 3B represent the P polarized component and the S polarized component, respectively.

[0040] After entering first substrate 120-1, first polarized light 310 changes from a P-polarized component to an S-polarized component as it travels toward second substrate 120-2 due to the twisting of the orientation of the liquid crystal molecules (see (2) to (4) in FIGS. 3A and 3B). More specifically, first polarized light 310 has a polarization axis in the x-axis direction on the first substrate 120-1 side, but gradually changes its polarization axis while passing through first liquid crystal layer 160-1 in the thickness direction, and has a polarization axis in the y-axis direction on the second substrate 120-2 side, and is then emitted from the second substrate 120-2 side (see (5) in FIGS. 3A and 3B).

[0041] Here, when a transverse electric field is generated between the first transparent electrode 130-1 and the second transparent electrode 130-2, the liquid crystal molecules on the first substrate 120-1 side are oriented in a convex arc shape along the x-axis direction under the influence of the transverse electric field, and the refractive index distribution changes. Therefore, the first polarized light 310 is diffused in the x-axis direction according to the refractive index distribution of the liquid crystal molecules. Also, when a transverse electric field is generated between the third transparent electrode 130-3 and the fourth transparent electrode 130-4, the liquid crystal molecules on the second substrate 120-2 side are oriented in a convex arc shape along the y-axis direction under the influence of the transverse electric field, and the refractive index distribution changes. Therefore, the first polarized light 310 is diffused in the y-axis direction according to the change in the refractive index distribution of the liquid crystal molecules.

[0042] Therefore, when no transverse electric field is generated (see FIG. 3A), the polarization component of the first polarized light 310 passing through the first liquid crystal cell 110-1 changes from P polarization to S polarization. On the other hand, when a transverse electric field is generated (see FIG. 3B), the polarization component of the first polarized light 310 passing through the first liquid crystal cell changes from P polarization to S polarization and is diffused in the x-axis and y-axis directions.

[0043] After entering first substrate 120-1, second polarized light 320 changes from an S-polarized component to a P-polarized component as it travels toward second substrate 120-2 due to the twist of the orientation of the liquid crystal molecules (see (2) to (4) in FIGS. 3A and 3B). More specifically, second polarized light 320 has a polarization axis in the y-axis direction on the first substrate 120-1 side, but gradually changes its polarization axis while passing through first liquid crystal layer 160-1 in the thickness direction, and has a polarization axis in the x-axis direction on the second substrate 120-2 side, and is then emitted from the second substrate 120-2 side (see (5) in FIGS. 3A and 3B).

[0044] Here, when a transverse electric field is generated between the first transparent electrode 130-1 and the second transparent electrode 130-2, the liquid crystal molecules on the first substrate 120-1 side are oriented in a convex arc shape along the x-axis direction due to the influence of the transverse electric field, and the refractive index distribution changes. However, since the polarization axis of the second polarized light 320 is perpendicular to the orientation of the liquid crystal molecules on the first substrate 120-1 side, it is not affected by the refractive index distribution of the liquid crystal molecules, and passes through as it is without diffusing. Also, when a transverse electric field is generated between the third transparent electrode 130-3 and the fourth transparent electrode 130-4, the liquid crystal molecules on the second substrate 120-2 side are oriented in a convex arc shape along the y-axis direction due to the influence of the transverse electric field, and the refractive index distribution changes. However, since the polarization axis of the second polarized light 320 is perpendicular to the orientation of the liquid crystal molecules on the second substrate 120-2 side, it is not affected by the refractive index distribution of the liquid crystal molecules, and passes through as it is without diffusing.

[0045] Therefore, not only when a transverse electric field is not generated (see FIG. 3A) but also when a transverse electric field is generated (see FIG. 3B), the second polarized light 320 passing through the first liquid crystal cell 110-1 changes in polarization component from an S polarization component to a P polarization component, but does not diffuse.

[0046] The liquid crystal molecules of the second liquid crystal layer 160-2 of the second liquid crystal cell 110-2 have a refractive index distribution similar to that of the liquid crystal molecules of the first liquid crystal layer 160-1 of the first liquid crystal cell 110-1. However, since the polarization axes of the first polarized light 310 and the second polarized light 320 are changed by passing through the first liquid crystal cell 110-1, the polarization affected by the refractive index distribution of the liquid crystal molecules of the second liquid crystal layer 160-2 is reversed. That is, not only when a transverse electric field is not generated (see FIG. 3A) but also when a transverse electric field is generated (see FIG. 3B), the polarization component of the first polarized light 310 passing through the second liquid crystal cell 110-2 changes from an S-polarized component to a P-polarized component, but it is not diffused (see (6) to (8) in FIG. 3A and FIG. 3B). On the other hand, when no transverse electric field is generated (see FIG. 3A), the polarization component of the second polarized light 320 passing through the second liquid crystal cell 110-2 simply changes from a P polarization component to an S polarization component. However, when a transverse electric field is generated (see FIG. 3B), the polarization component of the second polarized light 320 passing through the second liquid crystal cell 110-2 changes from a P polarization component to an S polarization component and is diffused in the x-axis and y-axis directions.

[0047] As can be seen from the above, in the optical element 10, by stacking two liquid crystal cells 110 having the same structure, the polarization component of the light incident on the optical element 10 is changed twice, and as a result, the polarization component before and after the incident can be made to remain the same (see (1) and (9) in FIG. 3A and FIG. 3B). On the other hand, the optical element 10 can supply a potential to the transparent electrode 130 to change the refractive index distribution of the liquid crystal molecules in the liquid crystal layer 160 of the liquid crystal cell 110, and refract the light passing through the liquid crystal cell 110. More specifically, the first liquid crystal cell 110-1 can diffuse the light of the first polarization 310 (P polarization component) in the x-axis direction, the y-axis direction, or both the x-axis and y-axis directions, and the second liquid crystal cell 110-2 can diffuse the light of the second polarization 320 (S polarization component) in the x-axis direction, the y-axis direction, or both the x-axis and y-axis directions.

[0048] 3A and 3B show only the first liquid crystal cell 110-1 and the second liquid crystal cell 110-2, and the light distribution of light transmitted through the first liquid crystal cell 110-1 and the second liquid crystal cell 110-2 has been described, but the light distribution of light transmitted through the third liquid crystal cell 110-3 and the fourth liquid crystal cell 110-4 is similar. However, the third liquid crystal cell 110-3 and the fourth liquid crystal cell 110-4 are stacked in a state rotated 90 degrees with respect to the first liquid crystal cell 110-1 and the second liquid crystal cell 110-2, and as a result, the polarized light components that act are interchanged. That is, the third liquid crystal cell 110-3 can diffuse the light of the second polarized light 320 (S-polarized component) in the x-axis direction, the y-axis direction, or both the x-axis and y-axis directions, and the fourth liquid crystal cell 110-4 can diffuse the light of the first polarized light 310 (P-polarized component) in the x-axis direction, the y-axis direction, or both the x-axis and y-axis directions.

[0049] [3. Supply of Electric Potential to Transparent Electrode of Optical Element 10] FIG. 4 is a schematic diagram illustrating the connection of the transparent electrodes 130 of the optical element 10 according to one embodiment of the present invention.

[0050] The first transparent electrode 130-1 and the fifteenth transparent electrode 130-15 are connected to a first potential supply line 200-1 that supplies a first potential V1. That is, the first transparent electrode 130-1 and the fifteenth transparent electrode 130-15 are electrically connected to each other.

[0051] The second transparent electrode 130-2 and the sixteenth transparent electrode 130-16 are connected to a second potential supply line 200-2 that supplies a second potential V2. That is, the second transparent electrode 130-2 and the sixteenth transparent electrode 130-16 are electrically connected to each other.

[0052] The third transparent electrode 130-3 and the thirteenth transparent electrode 130-13 are connected to a third potential supply line 200-3 that supplies a third potential V3. That is, the third transparent electrode 130-3 and the thirteenth transparent electrode 130-13 are electrically connected to each other.

[0053] The fourth transparent electrode 130-4 and the fourteenth transparent electrode 130-14 are connected to a fourth potential supply line 200-4 that supplies a fourth potential V4. That is, the fourth transparent electrode 130-4 and the fourteenth transparent electrode 130-14 are electrically connected to each other.

[0054] The fifth transparent electrode 130-5 and the eleventh transparent electrode 130-11 are connected to a fifth potential supply line 200-5 that supplies a fifth potential V5. That is, the fifth transparent electrode 130-5 and the eleventh transparent electrode 130-11 are electrically connected to each other.

[0055] The sixth transparent electrode 130-6 and the twelfth transparent electrode 130-12 are connected to a sixth potential supply line 200-6 that supplies a sixth potential V6. That is, the sixth transparent electrode 130-6 and the twelfth transparent electrode 130-12 are electrically connected to each other.

[0056] The seventh transparent electrode 130-7 and the ninth transparent electrode 130-9 are connected to a seventh potential supply line 200-7 that supplies a seventh potential V7. That is, the seventh transparent electrode 130-7 and the ninth transparent electrode 130-9 are electrically connected to each other.

[0057] The eighth transparent electrode 130-8 and the tenth transparent electrode 130-10 are connected to an eighth potential supply line 200-8 that supplies an eighth potential V8. That is, the eighth transparent electrode 130-8 and the tenth transparent electrode 130-10 are electrically connected to each other.

[0058] The first potential V1 to the eighth potential V8 may be fixed potentials or variable potentials. The first potential supply line 200-1 to the eighth potential supply line 200-8 are supplied with not only a low potential and a high potential, but also an intermediate potential between the low potential and the high potential. That is, the first potential V1 to the eighth potential include three potentials with different absolute values. This allows the optical element 10 to diffuse the light emitted from the light source in an elliptical shape with the minor and major axes adjusted. An example of an elliptical shape will be described below.

[0059] [Example 1. Elliptical shape with a focus on the y-axis] 5A to 5C, an elliptical light distribution having a focal point on the y-axis, i.e., an elliptical light distribution having a minor axis in the x-axis direction and a major axis in the y-axis direction, will be described. Note that, for convenience, the following description will be given assuming that the low potential and the high potential are -5V and 5V, respectively, but is not limited to this.

[0060] FIG. 5A is a timing chart showing the potential supplied to the transparent electrode 130 of the optical element 10 according to one embodiment of the present invention.

[0061] The first potential V1 and the second potential V2 are fluctuating potentials in which the intermediate potential is inverted. That is, the first potential V1 and the second potential V2 are potentials in which -2V and +2V are repeated. However, the phases of the first potential V1 and the second potential V2 are inverted. Therefore, the absolute value of the potential difference between the first potential V1 and the second potential V2 is 4V.

[0062] The third potential V3 and the fourth potential V4 are variable potentials in which the low potential and the high potential are inverted. That is, the third potential V3 and the fourth potential V4 are potentials in which -5V and +5V are repeated. However, the third potential V3 and the fourth potential V4 are inverted in phase. Therefore, the absolute value of the potential difference between the third potential V3 and the fourth potential V4 is 10V.

[0063] The fifth potential V5 and the sixth potential V6 are intermediate fixed potentials, i.e., the fifth potential V5 and the sixth potential V6 are 0V.

[0064] The seventh potential V7 and the eighth potential V8 are variable potentials in which the low potential and the high potential are inverted. That is, the seventh potential V7 and the eighth potential V8 are potentials in which -5V and +5V are repeated. However, the seventh potential V7 and the eighth potential V8 are inverted in phase. Therefore, the absolute value of the potential difference between the seventh potential V7 and the eighth potential V8 is 10V.

[0065] By supplying the above-mentioned potential to the transparent electrode 130, the alignment state of the liquid crystal molecules in the liquid crystal layer 160 changes according to the potential difference. Light polarized in the x-axis direction (e.g., P-polarized component) incident on the optical element 10 is diffused in the x-axis direction by the potential difference (4 V) between the first transparent electrode 130-1 and the second transparent electrode 130-2 and the potential difference (4 V) between the fifteenth transparent electrode 130-15 and the sixteenth transparent electrode 130-16. Light polarized in the x-axis direction incident on the optical element 10 is diffused in the y-axis direction by the potential difference (10 V) between the third transparent electrode 130-3 and the fourth transparent electrode 130-4 and the potential difference (10 V) between the thirteenth transparent electrode 130-13 and the fourteenth transparent electrode 130-14. Furthermore, light polarized in the y-axis direction (e.g., S-polarized component) incident on optical element 10 is diffused in the y-axis direction by the potential difference (10 V) between seventh transparent electrode 130-7 and eighth transparent electrode 130-8 and the potential difference (10 V) between ninth transparent electrode 130-9 and tenth transparent electrode 130-10. Therefore, of the light incident on optical element 10, a portion of the light polarized in the x-axis direction is diffused in the x-axis direction, and the remaining light is diffused in the y-axis direction. Therefore, the light transmitted through optical element 10 has an elliptical light distribution with a minor axis in the x-axis direction and a major axis in the y-axis direction.

[0066] In the timing chart shown in Fig. 5A, the light polarized in the x-axis direction is diffused in the x-axis direction, but it is also possible to diffuse the light polarized in the y-axis direction in the x-axis direction. This will be described below.

[0067] FIG. 5B is a timing chart showing the potential supplied to the transparent electrode 130 of the optical element 10 according to one embodiment of the present invention.

[0068] The first potential V1 and the second potential V2 are intermediate fixed potentials, i.e., the first potential V1 and the second potential V2 are 0V.

[0069] The third potential V3 and the fourth potential V4 are variable potentials in which the low potential and the high potential are inverted. That is, the third potential V3 and the fourth potential V4 are potentials in which -5V and +5V are repeated. However, the third potential V3 and the fourth potential V4 are inverted in phase. Therefore, the absolute value of the potential difference between the third potential V3 and the fourth potential V4 is 10V.

[0070] The fifth potential V5 and the sixth potential V6 are fluctuating potentials in which the intermediate potential is inverted. That is, the fifth potential V5 and the sixth potential V6 are potentials in which -2V and +2V are repeated. However, the fifth potential V5 and the sixth potential V6 are inverted in phase. Therefore, the absolute value of the potential difference between the fifth potential V5 and the sixth potential V6 is 4V.

[0071] The seventh potential V7 and the eighth potential V8 are variable potentials in which the low potential and the high potential are inverted. That is, the seventh potential V7 and the eighth potential V8 are potentials in which -5V and +5V are repeated. However, the seventh potential V7 and the eighth potential V8 are inverted in phase. Therefore, the absolute value of the potential difference between the seventh potential V7 and the eighth potential V8 is 10V.

[0072] When the above-mentioned potential is supplied to the transparent electrode 130, the alignment state of the liquid crystal molecules in the liquid crystal layer 160 changes according to the potential difference. The light polarized in the y-axis direction that is incident on the optical element 10 is diffused in the x-axis direction by the potential difference (4 V) between the fifth transparent electrode 130-5 and the sixth transparent electrode 130-6 and the potential difference (4 V) between the eleventh transparent electrode 130-11 and the twelfth transparent electrode 130-12. The light polarized in the y-axis direction that is incident on the optical element 10 is diffused in the y-axis direction by the potential difference (10 V) between the seventh transparent electrode 130-7 and the eighth transparent electrode 130-8 and the potential difference (10 V) between the ninth transparent electrode 130-9 and the tenth transparent electrode 130-10. Furthermore, the light polarized in the x-axis direction that is incident on optical element 10 is diffused in the y-axis direction by the potential difference (10 V) between third transparent electrode 130-3 and fourth transparent electrode 130-4 and the potential difference (10 V) between thirteenth transparent electrode 130-13 and fourteenth transparent electrode 130-14. Therefore, of the light that is incident on optical element 10, a part of the light polarized in the y-axis direction is diffused in the x-axis direction, and the remaining light is diffused in the y-axis direction. Therefore, the light that is transmitted through optical element 10 has an elliptical light distribution with a minor axis in the x-axis direction and a major axis in the y-axis direction.

[0073] Fig. 5C shows the results of measuring the azimuth angle of light transmitted through optical element 10 according to one embodiment of the present invention. When the potential shown in the timing chart of Fig. 5A was supplied to the manufactured optical element 10, the elliptical light distribution shown in Fig. 5C was measured.

[0074] [Example 2. Elliptical shape with a focus on the y-axis 2] 6A and 6B, a light distribution having an elliptical shape with a focal point on the y-axis, that is, with a minor axis in the x-axis direction and a major axis in the y-axis direction, will be described. Note that elliptical shape 2 is closer to a circle than elliptical shape 1.

[0075] FIG. 6A is a timing chart showing the potential supplied to the transparent electrode 130 of the optical element 10 according to one embodiment of the present invention.

[0076] The first potential V1 and the second potential V2 are fluctuating potentials in which the intermediate potential is inverted. That is, the first potential V1 and the second potential V2 are potentials in which -1V and +1V are repeated. However, the phases of the first potential V1 and the second potential V2 are inverted. Therefore, the absolute value of the potential difference between the first potential V1 and the second potential V2 is 2V.

[0077] The third potential V3 and the fourth potential V4 are variable potentials in which the low potential and the high potential are inverted. That is, the third potential V3 and the fourth potential V4 are potentials in which -5V and +5V are repeated. However, the third potential V3 and the fourth potential V4 are inverted in phase. Therefore, the absolute value of the potential difference between the third potential V3 and the fourth potential V4 is 10V.

[0078] The fifth potential V5 and the sixth potential V6 are fluctuating potentials in which the intermediate potential is inverted. That is, the fifth potential V5 and the sixth potential V6 are potentials in which -1V and +1V are repeated. However, the fifth potential V5 and the sixth potential V6 are inverted in phase. Therefore, the absolute value of the potential difference between the fifth potential V5 and the sixth potential V6 is 2V.

[0079] The seventh potential V7 and the eighth potential V8 are variable potentials in which the low potential and the high potential are inverted. That is, the seventh potential V7 and the eighth potential V8 are potentials in which -5V and +5V are repeated. However, the seventh potential V7 and the eighth potential V8 are inverted in phase. Therefore, the absolute value of the potential difference between the seventh potential V7 and the eighth potential V8 is 10V.

[0080] By supplying the above-mentioned potential to the transparent electrode 130, the alignment state of the liquid crystal molecules in the liquid crystal layer 160 changes according to the potential difference. Light polarized in the x-axis direction (e.g., P-polarized component) incident on the optical element 10 is slightly diffused in the x-axis direction by the potential difference (2V) between the first transparent electrode 130-1 and the second transparent electrode 130-2 and the potential difference (2V) between the fifteenth transparent electrode 130-15 and the sixteenth transparent electrode 130-16. In addition, light polarized in the x-axis direction incident on the optical element 10 is diffused in the y-axis direction by the potential difference (10V) between the third transparent electrode 130-3 and the fourth transparent electrode 130-4 and the potential difference (10V) between the thirteenth transparent electrode 130-13 and the fourteenth transparent electrode 130-14. Furthermore, the light polarized in the y-axis direction (for example, S-polarized component) incident on the optical element 10 is slightly diffused in the x-axis direction by the potential difference (2V) between the fifth transparent electrode 130-5 and the sixth transparent electrode 130-6 and the potential difference (2V) between the eleventh transparent electrode 130-11 and the twelfth transparent electrode 130-12. Also, the light is diffused in the y-axis direction by the potential difference (10V) between the seventh transparent electrode 130-7 and the eighth transparent electrode 130-8 and the potential difference (10V) between the ninth transparent electrode 130-9 and the tenth transparent electrode 130-10. Therefore, of the light incident on the optical element 10, a part of the light polarized in the x-axis direction and a part of the light polarized in the y-axis direction are diffused in the x-axis direction, and the remaining light is diffused in the y-axis direction. As a result, in the specific example 2, the brightness of the light diffused in the x-axis direction is increased compared to the elliptical shape 1 of the specific example 1. In addition, when comparing the brightness of light in the x-axis direction and the y-axis direction, the relative difference in brightness between the x-axis direction and the y-axis direction is small, so that the light passing through the optical element 10 has a light distribution with an elliptical shape close to a circle with the minor axis in the x-axis direction and the major axis in the y-axis direction.

[0081] FIG. 6B shows the measurement result of the azimuth angle of light transmitted through the optical element 10 according to one embodiment of the present invention. When the potential of the timing chart shown in FIG. 6A was supplied to the manufactured optical element 10, the elliptical light distribution shown in FIG. 6B was measured. As described above, the degree of diffusion in the x-axis direction is higher in this specific example 2 than in specific example 1. More specifically, not only a part of the light having polarization in the x-axis direction but also a part of the light having polarization in the y-axis direction is diffused in the x-axis direction. Therefore, the light distribution state of this specific example 2 shown in FIG. 6B is an elliptical light distribution closer to a circle than the light distribution state of specific example 1 shown in FIG. 5C.

[0082] [Example 3. Elliptical shape with a focus on the x-axis 3] With reference to FIGS. 7A to 7C, a light distribution having a focal point on the x-axis, that is, an elliptical shape having a major axis in the x-axis direction and a minor axis in the y-axis direction, will be described.

[0083] FIG. 7A is a timing chart showing the potential supplied to the transparent electrode 130 of the optical element 10 according to one embodiment of the present invention.

[0084] The first potential V1 and the second potential V2 are variable potentials in which the low potential and the high potential are inverted. That is, the first potential V1 and the second potential V2 are potentials in which -5V and +5V are repeated. However, the phases of the first potential V1 and the second potential V2 are inverted. Therefore, the absolute value of the potential difference between the first potential V1 and the second potential V2 is 10V.

[0085] The third potential V3 and the fourth potential V4 are fluctuating potentials in which the intermediate potential is inverted. That is, the third potential V3 and the fourth potential V4 are potentials in which -2V and +2V are repeated. However, the third potential V3 and the fourth potential V4 are inverted in phase. Therefore, the absolute value of the potential difference between the third potential V3 and the fourth potential V4 is 4V.

[0086] The fifth potential V5 and the sixth potential V6 are variable potentials in which the low potential and the high potential are inverted. That is, the fifth potential V5 and the sixth potential V6 are potentials in which -5V and +5V are repeated. However, the fifth potential V5 and the sixth potential V6 are inverted in phase. Therefore, the absolute value of the potential difference between the fifth potential V5 and the sixth potential V6 is 10V.

[0087] The seventh potential V7 and the eighth potential V8 are intermediate fixed potentials, i.e., the seventh potential V7 and the eighth potential V8 are 0V.

[0088] By supplying the above-mentioned potential to the transparent electrode 130, the alignment state of the liquid crystal molecules in the liquid crystal layer 160 changes according to the potential difference. Light polarized in the x-axis direction (e.g., P-polarized component) incident on the optical element 10 is diffused in the y-axis direction by the potential difference (4V) between the third transparent electrode 130-3 and the fourth transparent electrode 130-4 and the potential difference (4V) between the thirteenth transparent electrode 130-13 and the fourteenth transparent electrode 130-14. Light polarized in the x-axis direction incident on the optical element 10 is diffused in the x-axis direction by the potential difference (10V) between the first transparent electrode 130-1 and the second transparent electrode 130-2 and the potential difference (10V) between the fifteenth transparent electrode 130-15 and the sixteenth transparent electrode 130-16. Furthermore, light polarized in the y-axis direction (e.g., S-polarized component) incident on optical element 10 is diffused in the x-axis direction by the potential difference (10 V) between fifth transparent electrode 130-5 and sixth transparent electrode 130-6 and the potential difference (10 V) between eleventh transparent electrode 130-11 and twelfth transparent electrode 130-12. Therefore, of the light incident on optical element 10, a part of the light polarized in the x-axis direction is diffused in the y-axis direction, and the remaining light is diffused in the x-axis direction. Therefore, the light transmitted through optical element 10 has an elliptical light distribution with the major axis in the x-axis direction and the minor axis in the y-axis direction.

[0089] In the timing chart shown in Fig. 7A, the light polarized in the x-axis direction is diffused in the y-axis direction, but it is also possible to diffuse the light polarized in the y-axis direction in the y-axis direction. This will be described below.

[0090] FIG. 7B is a timing chart showing the potential supplied to the transparent electrode 130 of the optical element 10 according to one embodiment of the present invention.

[0091] The first potential V1 and the second potential V2 are variable potentials in which the low potential and the high potential are inverted. That is, the first potential V1 and the second potential V2 are potentials in which -5V and +5V are repeated. However, the phases of the first potential V1 and the second potential V2 are inverted. Therefore, the absolute value of the potential difference between the first potential V1 and the second potential V2 is 10V.

[0092] The third potential V3 and the fourth potential V4 are intermediate fixed potentials, i.e., the third potential V3 and the fourth potential V4 are 0V.

[0093] The fifth potential V5 and the sixth potential V6 are variable potentials in which the low potential and the high potential are inverted. That is, the fifth potential V5 and the sixth potential V6 are potentials in which -5V and +5V are repeated. However, the fifth potential V5 and the sixth potential V6 are inverted in phase. Therefore, the absolute value of the potential difference between the fifth potential V5 and the sixth potential V6 is 10V.

[0094] The seventh potential V7 and the eighth potential V8 are fluctuating potentials in which the intermediate potential is inverted. That is, the seventh potential V7 and the eighth potential V8 are potentials in which -2V and +2V are repeated. However, the seventh potential V7 and the eighth potential V8 are in phase with each other. Therefore, the absolute value of the potential difference between the seventh potential V7 and the eighth potential V8 is 4V.

[0095] When the above-mentioned potential is supplied to the transparent electrode 130, the alignment state of the liquid crystal molecules in the liquid crystal layer 160 changes according to the potential difference. The light polarized in the y-axis direction that is incident on the optical element 10 is diffused in the y-axis direction by the potential difference (4 V) between the seventh transparent electrode 130-7 and the eighth transparent electrode 130-8 and the potential difference (4 V) between the ninth transparent electrode 130-9 and the tenth transparent electrode 130-10. The light polarized in the y-axis direction that is incident on the optical element 10 is diffused in the x-axis direction by the potential difference (10 V) between the fifth transparent electrode 130-5 and the sixth transparent electrode 130-6 and the potential difference (10 V) between the eleventh transparent electrode 130-11 and the twelfth transparent electrode 130-12. Furthermore, the light polarized in the x-axis direction that is incident on optical element 10 is diffused in the x-axis direction by the potential difference (10 V) between first transparent electrode 130-1 and second transparent electrode 130-2 and the potential difference (10 V) between fifteenth transparent electrode 130-15 and sixteenth transparent electrode 130-16. Therefore, of the light that is incident on optical element 10, a part of the light polarized in the y-axis direction is diffused in the y-axis direction, and the remaining light is diffused in the x-axis direction. Therefore, the light that has passed through optical element 10 has an elliptical light distribution with the major axis in the x-axis direction and the minor axis in the y-axis direction.

[0096] Fig. 7C shows the results of measuring the azimuth angle of light transmitted through optical element 10 according to one embodiment of the present invention. When the potential shown in the timing chart of Fig. 7A was supplied to the manufactured optical element 10, the elliptical light distribution shown in Fig. 7C was measured.

[0097] [Example 4. Elliptical shape with a focus on the x-axis 4] 8A and 8B, a light distribution having an elliptical shape with a focal point on the x-axis, that is, with a major axis in the x-axis direction and a minor axis in the y-axis direction, will be described. Note that elliptical shape 4 is closer to a circle than elliptical shape 3.

[0098] FIG. 8A is a timing chart showing the potential supplied to the transparent electrode 130 of the optical element 10 according to one embodiment of the present invention.

[0099] The first potential V1 and the second potential V2 are variable potentials in which the low potential and the high potential are inverted. That is, the first potential V1 and the second potential V2 are potentials in which -5V and +5V are repeated. However, the phases of the first potential V1 and the second potential V2 are inverted. Therefore, the absolute value of the potential difference between the first potential V1 and the second potential V2 is 10V.

[0100] The third potential V3 and the fourth potential V4 are fluctuating potentials in which the intermediate potential is inverted. That is, the third potential V3 and the fourth potential V4 are potentials in which -1V and +1V are repeated. However, the third potential V3 and the fourth potential V4 are inverted in phase. Therefore, the absolute value of the potential difference between the third potential V3 and the fourth potential V4 is 2V.

[0101] The fifth potential V5 and the sixth potential V6 are variable potentials in which the low potential and the high potential are inverted. That is, the fifth potential V5 and the sixth potential V6 are potentials in which -5V and +5V are repeated. However, the fifth potential V5 and the sixth potential V6 are inverted in phase. Therefore, the absolute value of the potential difference between the fifth potential V5 and the sixth potential V6 is 10V.

[0102] The seventh potential V7 and the eighth potential V8 are fluctuating potentials in which the intermediate potential is inverted. That is, the seventh potential V7 and the eighth potential V8 are potentials in which -1V and +1V are repeated. However, the seventh potential V7 and the eighth potential V8 are inverted in phase. Therefore, the absolute value of the potential difference between the seventh potential V7 and the eighth potential V8 is 2V.

[0103] By supplying the above-mentioned potential to the transparent electrode 130, the alignment state of the liquid crystal molecules in the liquid crystal layer 160 changes according to the potential difference. Light polarized in the x-axis direction (e.g., P-polarized component) incident on the optical element 10 is slightly diffused in the y-axis direction by the potential difference (2V) between the third transparent electrode 130-3 and the fourth transparent electrode 130-4 and the potential difference (2V) between the thirteenth transparent electrode 130-13 and the fourteenth transparent electrode 130-14. Light polarized in the x-axis direction incident on the optical element 10 is diffused in the x-axis direction by the potential difference (10V) between the first transparent electrode 130-1 and the second transparent electrode 130-2 and the potential difference (10V) between the fifteenth transparent electrode 130-15 and the sixteenth transparent electrode 130-16. Furthermore, the light polarized in the y-axis direction (for example, S-polarized component) incident on the optical element 10 is slightly diffused in the y-axis direction by the potential difference (2V) between the seventh transparent electrode 130-7 and the eighth transparent electrode 130-8 and the potential difference (2V) between the ninth transparent electrode 130-9 and the tenth transparent electrode 130-10. Also, the light is diffused in the x-axis direction by the potential difference (10V) between the fifth transparent electrode 130-5 and the sixth transparent electrode 130-6 and the potential difference (10V) between the eleventh transparent electrode 130-11 and the twelfth transparent electrode 130-12. Therefore, of the light incident on the optical element 10, a part of the light polarized in the x-axis direction and a part of the light polarized in the y-axis direction are diffused in the y-axis direction, and the remaining light is diffused in the x-axis direction. As a result, in the specific example 4, the brightness of the light diffused in the y-axis direction is increased compared to the elliptical shape 3 of the specific example 3. In addition, when comparing the brightness of light in the x-axis direction and the y-axis direction, the relative difference in brightness between the x-axis direction and the y-axis direction is small, so that the light transmitted through the optical element 10 has an elliptical light distribution with the major axis in the x-axis direction and the minor axis in the y-axis direction.

[0104] FIG. 8B shows the measurement result of the azimuth angle of light transmitted through the optical element 10 according to one embodiment of the present invention. When the potential of the timing chart shown in FIG. 8A was supplied to the manufactured optical element 10, the elliptical light distribution shown in FIG. 8B was measured. As described above, in this specific example 4, the degree of diffusion in the y-axis direction is higher than that in specific example 3. More specifically, not only a part of the light having polarization in the y-axis direction but also a part of the light having polarization in the x-axis direction is diffused in the y-axis direction. Therefore, the light distribution state of this specific example 4 shown in FIG. 8B is an elliptical light distribution closer to a circle than the light distribution state of specific example 1 shown in FIG. 7C.

[0105] As described above, according to the optical element 10 according to one embodiment of the present invention, it is possible to control the lengths of the minor axis and the major axis in a light distribution having an elliptical shape, which is one type of anisotropic shape.

[0106] <Second embodiment> The optical element 10 can also provide a light distribution other than an elliptical shape. Hereinafter, a cross-shaped light distribution in which the length in the x-axis direction and the length in the y-axis direction are different will be described as an example of a light distribution other than an elliptical shape. Note that when the configuration of this embodiment is the same as that of the first embodiment, the description of the configuration may be omitted.

[0107] [Example 1. A cross shape with a length in the y-axis longer than the length in the x-axis] A cross-shaped light distribution in which the length in the y-axis direction is longer than the length in the x-axis direction will be described with reference to FIGS. 9A to 9C.

[0108] FIG. 9A is a timing chart showing the potential supplied to the transparent electrode 130 of the optical element 10 according to one embodiment of the present invention.

[0109] The first potential V1 and the second potential V2 are fluctuating potentials in which the intermediate potential is inverted. That is, the first potential V1 and the second potential V2 are potentials in which -2V and +2V are repeated. However, the phases of the first potential V1 and the second potential V2 are inverted. Therefore, the absolute value of the potential difference between the first potential V1 and the second potential V2 is 4V.

[0110] The third potential V3 and the fourth potential V4 are intermediate fixed potentials, i.e., the third potential V3 and the fourth potential V4 are 0V.

[0111] The fifth potential V5 and the sixth potential V6 are intermediate fixed potentials, i.e., the fifth potential V5 and the sixth potential V6 are 0V.

[0112] The seventh potential V7 and the eighth potential V8 are variable potentials in which the low potential and the high potential are inverted. That is, the seventh potential V7 and the eighth potential V8 are potentials in which -5V and +5V are repeated. However, the seventh potential V7 and the eighth potential V8 are inverted in phase. Therefore, the absolute value of the potential difference between the seventh potential V7 and the eighth potential V8 is 10V.

[0113] By supplying the above-mentioned potential to the transparent electrode 130, the alignment state of the liquid crystal molecules in the liquid crystal layer 160 changes according to the potential difference. Light polarized in the x-axis direction (e.g., P-polarized component) incident on the optical element 10 is diffused in the x-axis direction by the potential difference (4 V) between the first transparent electrode 130-1 and the second transparent electrode 130-2 and the potential difference (4 V) between the fifteenth transparent electrode 130-15 and the sixteenth transparent electrode 130-16. Light polarized in the y-axis direction (e.g., S-polarized component) incident on the optical element 10 is diffused in the y-axis direction by the potential difference (10 V) between the seventh transparent electrode 130-7 and the eighth transparent electrode 130-8 and the potential difference (10 V) between the ninth transparent electrode 130-9 and the tenth transparent electrode 130-10. Therefore, among the light incident on the optical element 10, a part of the light polarized in the x-axis direction is diffused in the x-axis direction, and the light polarized in the y-axis direction is diffused in the y-axis direction. In this way, a cross-shaped light distribution is realized by diffusing one polarized component only in the x-axis direction and the other polarized component only in the y-axis direction. In addition, the light distribution length in each direction of the cross-shaped light distribution is adjusted by adjusting the potential difference between the electrodes.

[0114] 9A, the light polarized in the x-axis direction is diffused in the x-axis direction, but it is also possible to diffuse the light polarized in the y-axis direction in the x-axis direction. This will be described below.

[0115] FIG. 9B is a timing chart showing the potential supplied to the transparent electrode 130 of the optical element 10 according to one embodiment of the present invention.

[0116] The first potential V1 and the second potential V2 are intermediate fixed potentials, i.e., the first potential V1 and the second potential V2 are 0V.

[0117] The third potential V3 and the fourth potential V4 are variable potentials in which the low potential and the high potential are inverted. That is, the third potential V3 and the fourth potential V4 are potentials in which -5V and +5V are repeated. However, the third potential V3 and the fourth potential V4 are inverted in phase. Therefore, the absolute value of the potential difference between the third potential V3 and the fourth potential V4 is 10V.

[0118] The fifth potential V5 and the sixth potential V6 are fluctuating potentials in which the intermediate potential is inverted. That is, the fifth potential V5 and the sixth potential V6 are potentials in which -2V and +2V are repeated. However, the fifth potential V5 and the sixth potential V6 are inverted in phase. Therefore, the absolute value of the potential difference between the fifth potential V5 and the sixth potential V6 is 4V.

[0119] The seventh potential V7 and the eighth potential V8 are intermediate fixed potentials, i.e., the seventh potential V7 and the eighth potential V8 are 0V.

[0120] By supplying the above-mentioned potential to the transparent electrode 130, the alignment state of the liquid crystal molecules in the liquid crystal layer 160 changes according to the potential difference. The light polarized in the y-axis direction that is incident on the optical element 10 is diffused in the x-axis direction by the potential difference (4V) between the fifth transparent electrode 130-5 and the sixth transparent electrode 130-6 and the potential difference (4V) between the eleventh transparent electrode 130-11 and the twelfth transparent electrode 130-12. The light polarized in the x-axis direction that is incident on the optical element 10 is diffused in the y-axis direction by the potential difference (10V) between the third transparent electrode 130-3 and the fourth transparent electrode 130-4 and the potential difference (10V) between the thirteenth transparent electrode 130-13 and the fourteenth transparent electrode 130-14. Therefore, of the light that is incident on the optical element 10, the light polarized in the x-axis direction is diffused in the y-axis direction, and a part of the light polarized in the y-axis direction is diffused in the x-axis direction.

[0121] Fig. 9C is a schematic diagram showing the shape of the light distribution when the potential of the timing chart shown in Fig. 9A or 9B is supplied to the transparent electrode 130 of the optical element 10 according to one embodiment of the present invention. The light transmitted through the optical element 10 has a cross-shaped light distribution in which the length in the y-axis direction is longer than the length in the x-axis direction, as shown in Fig. 9C.

[0122] [Example 2. Cross shape 2 where the length along the y-axis is shorter than the length along the x-axis] A cross-shaped light distribution in which the length in the y-axis direction is shorter than the length in the x-axis direction will be described with reference to FIGS. 10A to 10C.

[0123] FIG. 10A is a timing chart showing the potential supplied to the transparent electrode 130 of the optical element 10 according to one embodiment of the present invention.

[0124] The first potential V1 and the second potential V2 are intermediate fixed potentials, i.e., the first potential V1 and the second potential V2 are 0V.

[0125] The third potential V3 and the fourth potential V4 are fluctuating potentials in which the intermediate potential is inverted. That is, the third potential V3 and the fourth potential V4 are potentials in which -2V and +2V are repeated. However, the third potential V3 and the fourth potential V4 are inverted in phase. Therefore, the absolute value of the potential difference between the third potential V3 and the fourth potential V4 is 4V.

[0126] The fifth potential V5 and the sixth potential V6 are variable potentials in which the low potential and the high potential are inverted. That is, the fifth potential V5 and the sixth potential V6 are potentials in which -5V and +5V are repeated. However, the fifth potential V5 and the sixth potential V6 are inverted in phase. Therefore, the absolute value of the potential difference between the fifth potential V5 and the sixth potential V6 is 10V.

[0127] The seventh potential V7 and the eighth potential V8 are intermediate fixed potentials, i.e., the seventh potential V7 and the eighth potential V8 are 0V.

[0128] By supplying the above-mentioned potential to the transparent electrode 130, the alignment state of the liquid crystal molecules in the liquid crystal layer 160 changes according to the potential difference. Light polarized in the x-axis direction (e.g., P-polarized component) incident on the optical element 10 is diffused in the y-axis direction by the potential difference (4V) between the third transparent electrode 130-3 and the fourth transparent electrode 130-4 and the potential difference (4V) between the thirteenth transparent electrode 130-13 and the fourteenth transparent electrode 130-14. Light polarized in the y-axis direction (e.g., S-polarized component) incident on the optical element 10 is diffused in the x-axis direction by the potential difference (10V) between the fifth transparent electrode 130-5 and the sixth transparent electrode 130-6 and the potential difference (10V) between the eleventh transparent electrode 130-11 and the twelfth transparent electrode 130-12. Therefore, of the light incident on optical element 10, a portion of the light polarized in the x-axis direction is diffused in the y-axis direction, and the light polarized in the y-axis direction is diffused in the x-axis direction.

[0129] 10A, the light polarized in the x-axis direction is diffused in the y-axis direction, but it is also possible to diffuse the light polarized in the y-axis direction in the y-axis direction. This will be described below.

[0130] FIG. 10B is a timing chart showing the potential supplied to the transparent electrode 130 of the optical element 10 according to one embodiment of the present invention.

[0131] The first potential V1 and the second potential V2 are variable potentials in which the low potential and the high potential are inverted. That is, the first potential V1 and the second potential V2 are potentials in which -5V and +5V are repeated. However, the phases of the first potential V1 and the second potential V2 are inverted. Therefore, the absolute value of the potential difference between the first potential V1 and the second potential V2 is 10V.

[0132] The third potential V3 and the fourth potential V4 are intermediate fixed potentials, i.e., the third potential V3 and the fourth potential V4 are 0V.

[0133] The fifth potential V5 and the sixth potential V6 are intermediate fixed potentials, i.e., the fifth potential V5 and the sixth potential V6 are 0V.

[0134] The seventh potential V7 and the eighth potential V8 are fluctuating potentials in which the intermediate potential is inverted. That is, the seventh potential V7 and the eighth potential V8 are potentials in which -2V and +2V are repeated. However, the seventh potential V7 and the eighth potential V8 are in phase with each other. Therefore, the absolute value of the potential difference between the seventh potential V7 and the eighth potential V8 is 4V.

[0135] By supplying the above-mentioned potential to the transparent electrode 130, the alignment state of the liquid crystal molecules in the liquid crystal layer 160 changes according to the potential difference. The light polarized in the y-axis direction that is incident on the optical element 10 is diffused in the y-axis direction by the potential difference (4V) between the seventh transparent electrode 130-7 and the eighth transparent electrode 130-8 and the potential difference (4V) between the ninth transparent electrode 130-9 and the tenth transparent electrode 130-10. The light polarized in the x-axis direction that is incident on the optical element 10 is diffused in the x-axis direction by the potential difference (10V) between the first transparent electrode 130-1 and the second transparent electrode 130-2 and the potential difference (10V) between the fifteenth transparent electrode 130-15 and the sixteenth transparent electrode 130-16. Therefore, of the light that is incident on the optical element 10, a part of the light polarized in the y-axis direction is diffused in the y-axis direction, and the light polarized in the x-axis direction is diffused in the x-axis direction.

[0136] Fig. 10C is a schematic diagram showing the shape of the orientation when the potential of the timing chart shown in Fig. 10A or 10B is supplied to the transparent electrode 130 in the optical element 10 according to one embodiment of the present invention. The light transmitted through the optical element 10 has a cross-shaped light distribution in which the length in the y-axis direction is shorter than the length in the x-axis direction, as shown in Fig. 10C.

[0137] As described above, according to the optical element 10 according to one embodiment of the present invention, it is possible to control the lengths in the first and second directions in a light distribution having a cross shape, which is one type of anisotropic shape.

[0138] Although light distributions having several anisotropic shapes have been exemplified above, the length in the first direction and the length in the second direction can be controlled by the magnitude of the intermediate potential supplied to the transparent electrodes 130. For example, increasing the potential supplied to the transparent electrodes 130 causes the light to be diffused more, and the length increases. The shape of the light distribution can also be controlled by, for example, the distance between the substrates 120 or the pitch between the transparent electrodes 130.

[0139] Within the scope of the concept of the present invention, those skilled in the art may make various modifications and alterations, and it is understood that these modifications and alterations also fall within the scope of the present invention. For example, those in which a person skilled in the art appropriately adds, deletes, or modifies components of the above-mentioned embodiments, or adds, omits, or modifies conditions of steps, are also included in the scope of the present invention as long as they include the gist of the present invention.

[0140] Furthermore, other effects and advantages brought about by the aspects of this embodiment that are obvious from the description in this specification or that can be appropriately thought of by a person skilled in the art are naturally understood to be brought about by the present invention. [Explanation of symbols]

[0141] 10: Optical elements 110: Liquid crystal cell 120: Substrate 130: Transparent electrode 140: Alignment film 150: Sealing material 160: Liquid crystal layer 170: Optical elastic resin layer 200: potential supply line 310: 1st polarization 320: Second Polarization

Claims

1. A first liquid crystal cell; a second liquid crystal cell above the first liquid crystal cell; a third liquid crystal cell above the second liquid crystal cell; a fourth liquid crystal cell above the third liquid crystal cell; The first liquid crystal cell comprises: a first substrate on which first transparent electrodes and second transparent electrodes are alternately arranged in a comb-like shape in a first direction; a second substrate on which third transparent electrodes and fourth transparent electrodes are alternately arranged in a comb-like shape in a second direction intersecting the first direction, The second liquid crystal cell comprises: a third substrate adjacent to the second substrate, on which fifth transparent electrodes and sixth transparent electrodes are alternately arranged in a comb-like shape in the first direction; a fourth substrate on which seventh transparent electrodes and eighth transparent electrodes are alternately arranged in a comb-like shape in the second direction; The third liquid crystal cell comprises: a fifth substrate adjacent to the fourth substrate, on which ninth transparent electrodes and tenth transparent electrodes are alternately arranged in a comb-like shape in the second direction; a sixth substrate on which eleventh transparent electrodes and twelfth transparent electrodes are alternately arranged in a comb-like shape in the first direction; The fourth liquid crystal cell comprises: a seventh substrate adjacent to the sixth substrate, on which thirteenth transparent electrodes and fourteenth transparent electrodes are alternately arranged in a comb-like shape in a second direction; an eighth substrate on which fifteenth transparent electrodes and sixteenth transparent electrodes are alternately arranged in a comb-like shape in the first direction; a first potential is supplied to the first transparent electrode and the fifteenth transparent electrode; a second potential is supplied to the second transparent electrode and the sixteenth transparent electrode; a third potential is supplied to the third transparent electrode and the thirteenth transparent electrode; a fourth potential is supplied to the fourth transparent electrode and the fourteenth transparent electrode; a fifth potential is supplied to the fifth transparent electrode and the eleventh transparent electrode; a sixth potential is supplied to the sixth transparent electrode and the twelfth transparent electrode; a seventh potential is supplied to the seventh transparent electrode and the ninth transparent electrode; an eighth potential is supplied to the eighth transparent electrode and the tenth transparent electrode; The first to eighth potentials include three potentials having different absolute values.

2. 2. The optical element according to claim 1, wherein an absolute value of a potential difference between the first potential and the second potential is smaller than an absolute value of a potential difference between the third potential and the fourth potential and an absolute value of a potential difference between the seventh potential and the eighth potential.

3. The optical element according to claim 2 , wherein the fifth potential and the sixth potential are 0 V.

4. 2. The optical element according to claim 1, wherein an absolute value of a potential difference between the fifth potential and the sixth potential is smaller than an absolute value of a potential difference between the third potential and the fourth potential and an absolute value of a potential difference between the seventh potential and the eighth potential.

5. The optical element according to claim 4 , wherein the first potential and the second potential are 0V.

6. the third potential is equal to the seventh potential; The optical element according to claim 2 or 4, wherein the fourth potential is equal to the eighth potential.

7. the first potential is equal to the fifth potential; The optical element according to claim 6 , wherein the second potential is equal to the sixth potential.

8. 3. The optical element according to claim 2, wherein an absolute value of a potential difference between the third potential and the fourth potential is smaller than an absolute value of a potential difference between the first potential and the second potential and an absolute value of a potential difference between the fifth potential and the sixth potential.

9. The optical element according to claim 8 , wherein the seventh potential and the eighth potential are 0V.

10. 2. The optical element according to claim 1, wherein an absolute value of a potential difference between the seventh potential and the eighth potential is smaller than an absolute value of a potential difference between the first potential and the second potential and an absolute value of a potential difference between the fifth potential and the sixth potential.

11. The optical element according to claim 10 , wherein the third potential and the fourth potential are 0 V.

12. the first potential is equal to the fifth potential; The optical element according to claim 8 or 10, wherein the second potential is equal to the sixth potential.

13. the third potential is equal to the seventh potential; The optical element according to claim 12 , wherein the fourth potential is equal to the eighth potential.

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