Liquid crystal light control element and lighting device

Abstract

To provide a liquid crystal light control element capable of precisely controlling the intensity distribution of light emitted from a light source.SOLUTION: In a liquid crystal light control element, each of first to fourth liquid crystal cells includes a first substrate, a second substrate facing the first substrate, first to fourth electrodes having band-shaped patterns provided on the first substrate and the second substrate, and a liquid crystal layer between the first substrate and the second substrate. The liquid crystal cells are disposed in an overlapping manner. The band-shaped patterns of the first and second electrodes are disposed. The alignment direction of a first alignment film intersects with an extending direction of the band-shaped patterns of the first and second electrodes. The band-shaped patterns of the third and fourth electrodes are disposed. The alignment direction of a second alignment film intersects with an extending direction of the band-shaped patterns of the third and fourth electrodes and also intersects with the alignment direction of the first alignment film. In the first and fourth liquid crystal cells, the first and second electrodes have the same potential, and between the third and fourth electrodes, a lateral electric field is formed. In the second and third liquid crystal cells, a lateral electric field is formed between the first and second electrodes, and the third and fourth electrodes have the same potential.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] One embodiment of the present invention relates to an element that controls the distribution of light emitted from a light source by utilizing the electro-optic effect of liquid crystals. Another embodiment of the present invention relates to a device that includes an element that controls the distribution of light emitted from a light source by utilizing the electro-optic effect of liquid crystals. [Background technology]

[0002] Lighting devices equipped with liquid crystal lenses have been disclosed, including one in which two liquid crystal lenses are stacked together and the overlapping of strip-shaped transparent electrodes provided on each liquid crystal lens is adjusted to eliminate uneven light irradiation (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-230887 Summary of the Invention [Problem to be solved by the invention]

[0004] Lighting devices using liquid crystal lenses can control the diffusion of light in both the horizontal and vertical directions. However, the problem is that they cannot precisely control the light distribution in the polar angle direction. In other words, lighting devices using conventional liquid crystal lenses have the problem of being unable to precisely control the light distribution of diffused light.

[0005] An object of one embodiment of the present invention is to provide a liquid crystal light control element capable of precisely controlling the intensity distribution of light emitted from a light source, and an object of another embodiment of the present invention is to provide a lighting device including a liquid crystal light control element capable of precisely controlling the intensity distribution of light emitted from a light source. [Means for solving the problem]

[0006] A liquid crystal light control element according to one embodiment of the present invention has a plurality of liquid crystal cells, each of which includes a first substrate, a second substrate facing the first substrate, first and second electrodes having a strip-like pattern provided on at least one of the first and second substrates, a first alignment film provided on the first substrate, a second alignment film provided on the second substrate, and a liquid crystal layer between the first and second substrates. The plurality of liquid crystal cells are arranged one on top of the other, the strip-like patterns of the first electrodes and the second electrodes are alternately arranged, a voltage is applied so as to form a transverse electric field between the first and second electrodes, the alignment direction of the first alignment film is arranged so as to intersect with the extension direction of the strip-like pattern, and the alignment direction of the second alignment film is arranged so as to intersect with the alignment direction of the first alignment film. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a perspective view showing the structure of a liquid crystal cell that constitutes a liquid crystal light control element according to one embodiment of the present invention. [Figure 2A] 1 is a plan view showing electrodes provided on a first substrate of a liquid crystal cell that constitutes a liquid crystal light control element according to one embodiment of the present invention. [Figure 2B] 2 is a plan view showing electrodes provided on a second substrate of a liquid crystal cell constituting a liquid crystal light control element according to one embodiment of the present invention. FIG. [Figure 3] 1 shows an example of a cross-sectional structure of a liquid crystal cell that constitutes a liquid crystal light control element according to one embodiment of the present invention. [Figure 4A] 1A and 1B are diagrams for explaining the operation of a liquid crystal cell constituting a liquid crystal light control element according to one embodiment of the present invention, showing the alignment state of liquid crystal molecules when no voltage is applied. [Figure 4B] 1A and 1B are diagrams for explaining the operation of a liquid crystal cell constituting a liquid crystal light control element according to one embodiment of the present invention, showing the alignment state of liquid crystal molecules when a voltage is applied. [Figure 4C] 1A and 1B are diagrams for explaining the operation of a liquid crystal cell constituting a liquid crystal light control element according to one embodiment of the present invention, showing the alignment state of liquid crystal molecules when a voltage is applied. [Figure 5A]5A to 5C are diagrams illustrating the operation of a liquid crystal cell that constitutes a liquid crystal light control element according to one embodiment of the present invention. [Figure 5B] 1 is a diagram for explaining a liquid crystal cell that constitutes a liquid crystal light control element according to one embodiment of the present invention, and shows an example of the profile of a polarized wave emitted from the liquid crystal cell. [Figure 6] 1 shows the configuration (first configuration) of a liquid crystal light control element according to a first embodiment of the present invention and the state of diffusion. [Figure 7] 3 shows the waveform of a control signal applied to a liquid crystal cell that constitutes a liquid crystal light control element according to one embodiment of the present invention. [Figure 8] 1 shows the configuration of a liquid crystal light control element according to a first embodiment of the present invention (a modified example of the first configuration) and the state of diffusion. [Figure 9] 1 shows the configuration of a liquid crystal light control element according to a first embodiment of the present invention (a modified example of the first configuration) and the state of diffusion. [Figure 10] 2 shows the configuration (second configuration) of the liquid crystal light control element according to the first embodiment of the present invention and the state of diffusion. [Figure 11] 1 shows the configuration and diffusion state of a liquid crystal light control element according to a reference example. [Figure 12A] 1 shows a graph of the brightness-angle characteristics of the liquid crystal light control element according to the first embodiment of the present invention. [Figure 12B] 1 shows a profile of emitted light as a characteristic of the liquid crystal light control element according to the first embodiment of the present invention. [Figure 12C] 1 shows a profile of emitted light as a characteristic of the liquid crystal light control element according to the first embodiment of the present invention. [Figure 12D] 1 shows a profile of emitted light as a characteristic of the liquid crystal light control element according to the first embodiment of the present invention. [Figure 12E] 1 shows a profile of emitted light as a characteristic of the liquid crystal light control element according to the first embodiment of the present invention. [Figure 13] 10 shows the configuration (third configuration) of a liquid crystal light control element according to a second embodiment of the present invention and the state of diffusion. [Figure 14]10 shows the configuration (fourth configuration) of a liquid crystal light control element according to a second embodiment of the present invention and the state of diffusion. [Figure 15] 1 shows the configuration and diffusion state of a liquid crystal light control element according to a reference example. [Figure 16] 10 shows a graph of the brightness-angle characteristics of a liquid crystal light control element according to a second embodiment of the present invention. [Figure 17] 10 shows the configuration (fifth configuration) of a liquid crystal light control element according to a third embodiment of the present invention and the state of diffusion. [Figure 18] 10 shows the configuration (fifth configuration) of a liquid crystal light control element according to a third embodiment of the present invention and the state of diffusion. [Figure 19] 1 shows the configuration and diffusion state of a liquid crystal light control element according to a reference example. [Figure 20] 10 shows a graph of the brightness-angle characteristics of a liquid crystal light control element according to a third embodiment of the present invention. [Figure 21] 1 shows a perspective view of a lighting device according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different forms, and should not be construed as being limited to the description of the embodiments exemplified below. For clarity of explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual form, but these are merely examples and do not limit the interpretation of the present invention. Furthermore, in this specification and each drawing, elements similar to those previously described with reference to the previous drawings are designated by the same reference numerals (or reference numerals with a, b, etc. suffixed thereto), and detailed descriptions may be omitted as appropriate. Furthermore, the letters "first" and "second" attached to each element are convenient labels used to distinguish each element and have no further meaning unless otherwise specified.

[0009] In this specification, when a component or region is described as being "on (or under)" another component or region, unless otherwise specified, this includes not only the case where it is directly above (or directly under) the other component or region, but also the case where it is above (or under) the other component or region, i.e., the case where another component is included between the component or region and above (or under) the other component or region.

[0010] In this specification, "optical rotation" refers to the phenomenon in which the polarization axis of a linearly polarized component is rotated when passing through a liquid crystal layer.

[0011] In this specification, the "alignment direction" of an alignment film refers to the direction in which liquid crystal molecules are aligned when the alignment film is subjected to a treatment (e.g., a rubbing treatment) that imparts an alignment restraining force to the alignment film and aligns the liquid crystal molecules on the alignment film. When the treatment performed on the alignment film is a rubbing treatment, the alignment direction of the alignment film is usually the rubbing direction.

[0012] In this specification, the "extension direction" of a belt-shaped pattern refers to the direction in which the long side of a pattern having a short side (width) and a long side (length) extends when the belt-shaped pattern is viewed in a plan view. Note that the belt-shaped pattern includes a rectangular pattern in a plan view, and also includes a pattern whose long side is bent or curved at least once along the way.

[0013] In this specification, the term "polar angle" refers to the angle formed between the normal direction to the main surface of the liquid crystal panel and the traveling direction of the emitted light.

[0014] FIG. 1 is a perspective view showing the configuration of a first liquid crystal cell 10. The first liquid crystal cell 10 includes a first substrate S11, a second substrate S12, and a first liquid crystal layer LC1 between the first substrate S11 and the second substrate S12. A first electrode E11 and a first alignment film AL11 are provided on the first substrate S11, and a second electrode E12 and a second alignment film AL12 are provided on the second substrate S12. The first alignment film AL11 covers the first electrode E11, and the second alignment film AL12 covers the second electrode E12. The first electrode E11 and the first alignment film AL11 are disposed on the first substrate S11 facing the first liquid crystal layer LC1, and the second electrode E12 and the second alignment film AL12 are disposed on the second substrate S12 facing the first liquid crystal layer LC1. The first electrode E11 and the second electrode E12 face each other with the first liquid crystal layer LC1 interposed therebetween.

[0015] The first electrode E11 includes first strip electrodes E11A and second strip electrodes E11B having a strip-shaped pattern (or a comb-like pattern). The second electrode E12 includes third strip electrodes E12A and fourth strip electrodes E12B having a strip-shaped pattern (or a comb-like pattern). A plurality of the first strip electrodes E11A and second strip electrodes E11B are alternately arranged on the insulating surface of the first substrate S11, and a plurality of the third strip electrodes E12A and fourth strip electrodes E12B are alternately arranged on the insulating surface of the second substrate S12.

[0016] 1 shows the X, Y, and Z axis directions for the sake of explanation. In the first liquid crystal cell 10, the extension directions of the first strip electrode E11A and the multiple second strip electrodes E11B are arranged parallel to the X axis direction, and the extension directions of the third strip electrode E12A and the multiple fourth strip electrodes E12B are arranged parallel to the Y axis direction. The third strip electrode E12A and the fourth strip electrode E12B are arranged to intersect with the first strip electrode E11A and the second strip electrode E11B. The extension directions of the first strip electrode E11A and the second strip electrode E11B intersect with the extension directions of the third strip electrode E12A and the fourth strip electrode E12B within a range of 90±10 degrees, for example, and are preferably perpendicular (90 degrees).

[0017] The first alignment film AL11 and the second alignment film AL12 have an alignment regulating force substantially parallel to the main planes of the respective substrates. The alignment direction of the first alignment film AL11 is set in a direction (Y-axis direction) intersecting with the extension direction of the first strip electrodes E11A and the second strip electrodes E11B, and the alignment direction of the second alignment film AL12 is set in a direction (X-axis direction) intersecting with the extension direction of the third strip electrodes E12A and the fourth strip electrodes E12B. The angle at which the alignment directions of the first alignment film AL11 and the second alignment film AL12 intersect with the extension direction of the strip electrodes can be set within a range of 90±10 degrees.

[0018] The first liquid crystal layer LC1 uses, for example, twisted nematic (TN) liquid crystal. When no voltage is applied to the first electrode E11 and the second electrode E12, the first liquid crystal layer LC1 is affected by the alignment regulating force of the first alignment film AL11 and the second alignment film AL12, and the long axis direction of the liquid crystal molecules LCM is aligned parallel to the alignment direction. Since the alignment direction of the first alignment film AL11 and the alignment direction of the second alignment film AL12 are intersecting (orthogonal), the long axis direction of the liquid crystal molecules LCM gradually changes so as to be twisted 90 degrees from the first substrate S11 to the second substrate S12. Although not shown in FIG. 1, a spacer may be provided between the first substrate S11 and the second substrate S12 to maintain a constant gap.

[0019] 1, the alignment state of the liquid crystal molecules LCM on the first substrate S11 side changes when a voltage is applied between the first strip electrodes E11A and the second strip electrodes E11B so as to generate a potential difference between the liquid crystal molecules LCM in their initial alignment state. Also, the alignment state of the liquid crystal molecules LCM on the second substrate S12 side changes when a voltage is applied between the third strip electrodes E12A and the fourth strip electrodes E12B so as to generate a potential difference.

[0020] FIG. 2A shows a plan view of the first substrate S11, and FIG. 2B shows a plan view of the second substrate S12.

[0021] 2A, a first electrode E11 is provided on a first substrate S11. The first electrode E11 includes a plurality of first strip electrodes E11A and a plurality of second strip electrodes E11B. The plurality of first strip electrodes E11A and the plurality of second strip electrodes E11B have strip patterns. The strip patterns of the plurality of first strip electrodes E11A and the strip patterns of the plurality of second strip electrodes E11B are alternately arranged at predetermined intervals in a direction intersecting the extension direction.

[0022] The plurality of first strip-shaped electrodes E11A are each connected to a first power supply line PE11, and the plurality of second strip-shaped electrodes E11B are each connected to a second power supply line PE12. The first power supply line PE11 is connected to a first connection terminal T11, and the second power supply line PE12 is connected to a second connection terminal T12. The first connection terminal T11 and the second connection terminal T12 are provided along one side of the edge of the first substrate S11. The first substrate S11 is provided with a third connection terminal T13 adjacent to the first connection terminal T11, and a fourth connection terminal T14 adjacent to the second connection terminal T12. The third connection terminal T13 is connected to a fifth power supply line PE15. The fifth power supply line PE15 is connected to a first power supply terminal PT11 provided at a predetermined position within the surface of the first substrate S11. The fourth connection terminal T14 is connected to a sixth power supply line PE16. The sixth power supply line PE16 is connected to a second power supply terminal PT12 provided at a predetermined position on the surface of the first substrate S11.

[0023] The multiple first strip electrodes E11A are connected to a first power supply line PE11, and the same voltage is applied to them. The multiple second strip electrodes E11B are connected to a second power supply line PE12, and the same voltage is applied to them. When different voltages are applied to the multiple first strip electrodes E11A and the multiple second strip electrodes E11B, an electric field is generated between the two electrodes due to the potential difference. In other words, a horizontal electric field is generated by the multiple first strip electrodes E11A and the multiple second strip electrodes E11B.

[0024] As shown in FIG. 2B, the second substrate S12 is provided with a second electrode E12. The second electrode E12 includes a plurality of third strip electrodes E12A and a plurality of fourth strip electrodes E12B. The third strip electrodes E12A and the fourth strip electrodes E12B have a strip pattern. The strip patterns of the third strip electrodes E12A and the strip patterns of the fourth strip electrodes E12B are alternately arranged at predetermined intervals in a direction intersecting the extension direction. The third strip electrodes E12A and the fourth strip electrodes E12B are arranged at an angle of 90±10 degrees with respect to the extension direction of the first strip electrodes E11A and the second strip electrodes E11B.

[0025] The plurality of third strip-shaped electrodes E12A are each connected to a third power supply line PE13, and the plurality of fourth strip-shaped electrodes E12B are each connected to a fourth power supply line PE14. The third power supply line PE13 is connected to a third power supply terminal PT13, and the fourth power supply line PE14 is connected to a fourth power supply terminal PT14. The third power supply terminal PT13 is provided at a position corresponding to the first power supply terminal PT11 on the first substrate S11, and the fourth power supply terminal PT14 is provided at a position corresponding to the second power supply terminal PT12 on the first substrate S11.

[0026] The plurality of third strip-shaped electrodes E12A are connected to a third power supply line PE13, and the same voltage is applied to the plurality of fourth strip-shaped electrodes E12B. The same voltage is applied to the plurality of fourth strip-shaped electrodes E12B, and the same voltage is applied to the plurality of third strip-shaped electrodes E12A. When different voltages are applied to the plurality of third strip-shaped electrodes E12A and the plurality of fourth strip-shaped electrodes E12B, an electric field is generated between the two electrodes due to the potential difference. That is, a horizontal electric field is generated by the plurality of third strip-shaped electrodes E12A and the plurality of fourth strip-shaped electrodes E12B.

[0027] The connection terminals T11 to T14 provided on the first substrate S11 are connected to the flexible wiring board. In the first liquid crystal cell 10, the first power supply terminal PT11 and the third power supply terminal PT13 are electrically connected by a conductive material, and the second power supply terminal PT12 and the fourth power supply terminal PT14 are electrically connected by a conductive material.

[0028] Fig. 3 shows a cross-sectional view of the first liquid crystal cell 10. The cross-sectional structure of the first liquid crystal cell 10 shown in Fig. 3 corresponds to the A1-A2 line of the first substrate S11 shown in Fig. 2A and the second substrate S12 shown in Fig. 2B.

[0029] The first liquid crystal cell 10 has an effective area AA through which incident light passes. The first electrode E11 and the second electrode E12 are disposed within the effective area AA. The first substrate S11 and the second substrate S12 are bonded together by a sealant SE provided outside the effective area AA. The first liquid crystal layer LC1 is sealed between the first substrate S11 and the second substrate S12 by the sealant SE.

[0030] The first power supply terminal PT11 has a structure continuing from the fifth power supply line PE15 and is arranged outside the sealing material SE. The third power supply terminal PT13 has a structure continuing from the third power supply line PE13 and is arranged outside the sealing material SE.

[0031] The first and third power supply terminals PT11 and PT13 are arranged facing each other in an area outside the sealing material SE. The first conductive member CP11 is arranged between the first and third power supply terminals PT11 and PT13 and electrically connects them. The first conductive member CP11 can be formed from a conductive paste material, such as silver paste or carbon paste. Although not shown in FIG. 3, the second and fourth power supply terminals PT12 and PT14 are also electrically connected by a conductive member.

[0032] The first substrate S11 and the second substrate S12 are light-transmitting substrates, such as a glass substrate or a resin substrate. The first electrode E11 and the second electrode E12 are transparent electrodes made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). The power supply lines (first power supply line PE11, second power supply line PE12, third power supply line PE13, fourth power supply line PE14, fifth power supply line PE15, sixth power supply line PE16), connection terminals (first connection terminal T11, second connection terminal T12, third connection terminal T13, fourth connection terminal T14), and power supply terminals (first power supply terminal PT11, second power supply terminal PT12, third power supply terminal PT13, fourth power supply terminal PT14) are made of a metal material such as aluminum, titanium, molybdenum, or tungsten. The power supply lines (first power supply line PE11, second power supply line PE12, third power supply line PE13, fourth power supply line PE14, fifth power supply line PE15, sixth power supply line PE16) may be formed of the same transparent conductive film as the first electrode E11 and the second electrode E12. Of course, a configuration in which either or both of the first electrode E11 and the second electrode E12 are formed of a metal material can also be employed.

[0033] FIG. 4A shows a partial perspective view of the first liquid crystal cell 10. FIG. 4A shows the arrangement of the first and second strip electrodes E11A and E11B, the third and fourth strip electrodes E12A and E12B, and the first liquid crystal layer LC1. FIGS. 4B and 4C show schematic cross-sectional views of the first liquid crystal cell 10. FIGS. 4B and 4C show schematic cross-sectional views of the first liquid crystal cell 10 shown in FIG. 4A as viewed from side A and side B, respectively. Note that FIGS. 4B and 4C show that the alignment treatment direction of the first alignment film AL11 is different from the alignment treatment direction of the second alignment film AL12.

[0034] 4A, the first strip electrode E11A and the second strip electrode E11B are arranged with a center-to-center distance W, and the third strip electrode E12A and the fourth strip electrode E12B are similarly arranged with a center-to-center distance W. As shown in FIG. 4A, this center-to-center distance W has the relationship W=a+b, where "a" is the width of the first strip electrode E11A and "b" is the distance from the end of the first strip electrode E11A to the end of the second strip electrode E11B.

[0035] 4B and 4C, the first substrate S11 and the second substrate S12 are disposed opposite each other with a gap D therebetween. The gap D is the distance between the substrates, but it substantially corresponds to the thickness of the first liquid crystal layer LC1. In reality, the first substrate S11 is provided with first strip electrodes E11A and a first alignment film AL11, and the second substrate S12 is provided with third strip electrodes E12A and a second alignment film AL12, etc., but the thicknesses of these electrodes and alignment films are sufficiently smaller than the size of the gap D, so the thickness of the first liquid crystal layer LC1 is substantially the same as the gap D.

[0036] The distance D corresponding to the thickness of the first liquid crystal layer LC1 is preferably equal to or greater than the center-to-center distance W of the strip electrodes (D≧W). The distance D is preferably at least one time the center-to-center distance W. For example, the distance D corresponding to the thickness of the first liquid crystal layer LC1 is preferably at least twice the center-to-center distance W of the strip electrodes. For example, if the width of the first strip electrode E11A is 5 μm, the widths a of the first strip electrode E11A and the second strip electrode E11B are 5 μm, and the distance b from the end of the first strip electrode E11A to the end of the second strip electrode E11B is 5 μm, the center-to-center distance W of the strip electrodes is 10 μm. In contrast, the distance D corresponding to the thickness of the first liquid crystal layer LC1 is preferably at least 10 μm.

[0037] By having this relationship between the center-to-center distance W of the strip electrodes and the distance D corresponding to the thickness of the first liquid crystal layer LC1, mutual interference between the electric field generated between the first strip electrode E11A and the second strip electrode E11B and the electric field generated between the third strip electrode E12A and the fourth strip electrode E12B is suppressed.

[0038] It is known that the refractive index of liquid crystal changes depending on its orientation state. As shown in FIG. 1, in the OFF state where no electric field is applied to the first liquid crystal layer LC1, the long axis direction of the liquid crystal molecules is aligned horizontally to the surface of the substrate, and is twisted by 90 degrees from the first substrate S11 side to the second substrate S12 side. In this state, the first liquid crystal layer LC1 has a uniform refractive index distribution. When light is incident on the first liquid crystal cell 10, the polarization component of the incident light changes direction due to the twist of the liquid crystal molecules LCM. Hereinafter, this action of the liquid crystal layer is referred to as optical rotation. In this case, the incident light is rotated but passes through the first liquid crystal layer LC1 without being refracted (or scattered).

[0039] On the other hand, as shown in Fig. 4C, in the ON state in which an electric field is generated between the first strip electrode E11A and the second strip electrode E11B, the long axes of the liquid crystal molecules LCM are aligned along the electric field (when the liquid crystal has positive dielectric anisotropy). As a result, as shown in Fig. 4C, the first liquid crystal layer LC1 has regions in which the liquid crystal molecules LCM stand up above the first strip electrode E11A and the second strip electrode E11B, regions in which they are aligned obliquely along the distribution of the electric field between the first strip electrode E11A and the second strip electrode E11B, and regions away from the first substrate S11 in which their initial alignment state is maintained.

[0040] Similarly, as shown in Figure 4B, when the on state is entered in which an electric field is generated between the third strip electrode E12A and the fourth strip electrode E12B, the first liquid crystal layer LC1 forms regions in which the liquid crystal molecules LCM stand up above the third strip electrode E12A and the fourth strip electrode E12B, regions in which they are oriented diagonally in line with the distribution of the electric field between the third strip electrode E12A and the fourth strip electrode E12B, and regions away from the second substrate S12 in which their initial orientation state is maintained.

[0041] 4B and 4C, when an electric field is generated between the first strip electrode E11A and the second strip electrode E11B and between the third strip electrode E12A and the fourth strip electrode E12B, a region is formed in which the long axes of the liquid crystal molecules LCM are aligned in a convex arc shape along the direction of the electric field. That is, as shown in Figures 4A and 4B, when the initial alignment direction of the liquid crystal molecules LCM is the same as the direction of the transverse electric field generated between the first strip electrode E11A and the second strip electrode E11B, the liquid crystal molecules LCM are aligned in a tilted direction normal to the surface of the first substrate S11 in accordance with the intensity distribution of the electric field.

[0042] 4B and 4C, the distance D, which corresponds to the thickness of the first liquid crystal layer LC1, is sufficiently large, so that the electric field on the first substrate S11 side has a significantly small effect on the alignment of the liquid crystal molecules on the second substrate S12 side, and vice versa.

[0043] A transverse electric field is generated by the strip electrodes, resulting in a convex arc-shaped dielectric constant distribution in the first liquid crystal layer LC1. Of the light incident on the first liquid crystal layer LC1, the polarization component parallel to the initial alignment direction of the liquid crystal molecules LCM is diffused radially by this dielectric constant distribution. As shown in Figures 4B and 4C, the alignment directions of the liquid crystal molecules LCM on the first substrate S11 side and the second substrate S12 side intersect (are perpendicular), so the light is diffused in different directions on the first substrate S11 side and the second substrate S12 side.

[0044] In this way, when light passes through the first liquid crystal cell 10, some polarized components are diffused and transmitted depending on the state of the electric field formed in the first liquid crystal layer LC1, and the remaining polarized components are transmitted through the first liquid crystal LC1 as is.

[0045] 5A shows a first liquid crystal cell 10 in which the strip electrodes of the first electrode E11 extend in the X-axis direction and the strip electrodes of the second electrode E12 extend in the Y-axis direction. A voltage is applied to the first electrode E11 so as to generate a transverse electric field (in the Y-axis direction) between the first strip electrodes E11A and the second strip electrodes E11B, and a voltage is applied to the second electrode E12 so as to generate a transverse electric field (in the X-axis direction) between the third strip electrodes E12A and the fourth strip electrodes E12B.

[0046] 5A shows a state in which, in such a bias state, light containing a first polarization component PL1 parallel to the X-axis direction and a second polarization component PL2 parallel to the Y-axis direction enters the first liquid crystal cell 10 through the first substrate S11 and exits through the second substrate S12. Here, the first polarization component PL1 corresponds to an S wave, and the second polarization component PL2 corresponds to a P wave.

[0047] In the first liquid crystal cell 10, the long axes of the liquid crystal molecules LCM on the first substrate S11 side are oriented in the Y-axis direction, and the long axes of the liquid crystal molecules LCM on the second substrate S12 side are oriented in the X-axis direction. Of the light incident from the first substrate S11 side, the first polarization component PL1 of light is transmitted as is because its polarization direction intersects with the long axes of the liquid crystal molecules LCM, while the second polarization component PL2 of light is polarized parallel to the long axes of the liquid crystal molecules LCM and is therefore diffused in the Y-axis direction due to the influence of the arc-shaped refractive index distribution formed by the alignment of the liquid crystal molecules LCM. As the first polarization component PL1 of light travels through the first liquid crystal layer LC1 from the first substrate S11 side to the second substrate S12 side, it is rotated by 90 degrees. At this time, its polarization direction becomes perpendicular to the alignment direction of the long axes of the liquid crystal molecules on the second substrate S12 side, so it is transmitted as is and exits the second substrate S12. On the other hand, the second polarization component PL2 is rotated by 90 degrees as it travels through the first liquid crystal layer LC1 from the first substrate S11 side to the second substrate S12 side, and since the polarization direction at this time becomes parallel to the orientation direction of the long axes of the liquid crystal molecules on the second substrate S12 side, it is diffused in the X-axis direction and emitted from the second substrate S12.

[0048] In this way, when light is incident on the first liquid crystal cell 10 shown in FIG. 5A, the first polarized component PL1 (S wave) is not diffused, and the second polarized component PL2 (P wave) is diffused in the X-axis and Y-axis directions.

[0049] Figure 5B shows the profile of the S-wave (emitted P-wave). As mentioned above, the first polarized component PL1 (S-wave) should not, in principle, be diffused. However, the profile in Figure 5B shows that the first polarized component PL1 (S-wave) is slightly diffused in the Y-axis direction. This suggests that the second polarized component PL2 (P-wave) diffused in the Y-axis direction on the first substrate S11 side still contains a component that was not fully optically rotated in the first liquid crystal layer LC1.

[0050] Thus, if any polarization components that have not been rotated by the liquid crystal cell remain, it will affect the profile of the emitted light. The liquid crystal light control element 102 exemplified in the embodiment shown below has a configuration in which multiple liquid crystal cells are stacked to enable precise control of the profile of the emitted light.

[0051] [First embodiment] This embodiment shows an example in which the liquid crystal light control element is composed of four liquid crystal cells. Each liquid crystal cell has a liquid crystal layer between a pair of substrates, and strip electrodes as shown in Figure 1 are provided on at least one of the substrates.

[0052] 1-1. First Configuration 6 shows the electrode arrangement in each liquid crystal cell of a liquid crystal light control element 102 according to the first configuration, and the state when light incident on the liquid crystal light control element 102 passes through each liquid crystal cell. The liquid crystal light control element 102 according to the first configuration has a first liquid crystal cell 10, a second liquid crystal cell 20, a third liquid crystal cell 30, and a fourth liquid crystal cell 40 stacked from the light incident side to the light exit side. For the sake of explanation, FIG. 6 shows the X-axis, Y-axis, and Z-axis. In the following explanation, the X-axis direction refers to the direction along the X-axis, the Y-axis direction refers to the direction along the Y-axis, and the Z-axis direction refers to the direction along the Z-axis.

[0053] In the liquid crystal light control element 102 according to the first configuration, a first liquid crystal cell 10, a second liquid crystal cell 20, a third liquid crystal cell 30, and a fourth liquid crystal cell 40 are arranged so as to overlap in the Z-axis direction. In an actual liquid crystal light control element 102, the liquid crystal cells are arranged so as to be in close contact with each other, but for the sake of explanation, Fig. 6 shows the liquid crystal cells in an expanded state.

[0054] The first liquid crystal cell 10 has a structure in which first electrodes (first strip electrodes E11A and second strip electrodes E11B) are provided on the first substrate S11, a second electrode E12 (a planar (also referred to as a flat or solid) electrode) is provided on the second substrate S12, and a first liquid crystal layer LC1 is provided between the first substrate S11 and the second substrate S12. The first strip electrodes E11A and the second strip electrodes E11B are provided so that they extend in the Y-axis direction. Note that although the alignment films are omitted in FIG. 6, the alignment directions of the alignment films are indicated by arrows. That is, the alignment direction of the first alignment film AL11 (not shown) on the first substrate S11 side is oriented in the X-axis direction, and the alignment direction of the second alignment film AL12 (not shown) on the second substrate S12 side is oriented in the Y-axis direction. The crossing angle between the alignment direction of the first alignment film AL11 and the alignment direction of the second alignment film AL12 is preferably 90±10 degrees, and more preferably 90 degrees (orthogonal).

[0055] The second liquid crystal cell 20 includes a first substrate S21 and a second substrate S22, a first electrode E21 (a first strip electrode E21A and a second strip electrode E21B) and a second electrode E22 (a planar (also referred to as a flat or solid) electrode), and a second liquid crystal layer LC2 between the first substrate S21 and the second substrate S22. The second liquid crystal cell 20 has a similar configuration to the first liquid crystal cell 10. That is, the second liquid crystal cell 20 is arranged so that the extension direction of the first strip electrode E21A and the second strip electrode E21B extends in the Y-axis direction.

[0056] The third liquid crystal cell 30 includes a first substrate S31 and a second substrate S32, a first electrode E31 (a first strip-shaped electrode E31A and a second strip-shaped electrode E31B) and a second electrode E32 (a planar (also referred to as a flat or solid) electrode), and a third liquid crystal layer LC3 between the first substrate S31 and the second substrate S32. The third liquid crystal cell 30 has a configuration similar to that of the first liquid crystal cell 10, but is arranged so that the extension direction of the first strip-shaped electrode E31A and the second strip-shaped electrode E31B extends in the X-axis direction. Accordingly, the alignment direction of the alignment film is oriented in the Y-axis direction on the first substrate S31 side and in the X-axis direction on the second substrate S32 side.

[0057] The fourth liquid crystal cell 40 includes a first substrate S41, a second substrate S42, a first electrode E41 (a first strip electrode E41A and a second strip electrode E41B), a second electrode E42 (a planar (also referred to as a flat or solid) electrode), and a fourth liquid crystal layer LC4 between the first substrate S41 and the second substrate S42. The fourth liquid crystal cell 40 has a configuration similar to that of the third liquid crystal cell 30. That is, the fourth liquid crystal cell 40 is arranged such that the extension direction of the first strip electrode E41A and the second strip electrode E41B extends in the X-axis direction. Furthermore, the alignment direction of the alignment film is oriented in the Y-axis direction on the first substrate S41 side and in the X-axis direction on the second substrate S42 side.

[0058] As described above, in the liquid crystal light control element 102 according to the first configuration, the liquid crystal alignment direction of the first liquid crystal cell 10 and the second liquid crystal cell 20 is the same, and the extension directions of the strip-shaped electrodes (E11A, E11B, E21A, E21B) of the first electrodes E11 and E21 are directed in the same direction. In addition, the liquid crystal alignment direction of the third liquid crystal cell 30 and the fourth liquid crystal cell 40 is the same, and the extension directions of the strip-shaped electrodes (E31A, E31B, E41A, E41B) of the first electrodes E31 and E41 are directed in the same direction. The extension direction of the strip electrodes (E11A, E11B, E21A, E21B) of the first electrodes E11, E21 in the first liquid crystal cell 10 and the second liquid crystal cell 20 intersects at an angle of 90° with the extension direction of the strip electrodes (E31A, E31B, E41A, E41B) of the first electrodes E31, E41 in the third liquid crystal cell 30 and the fourth liquid crystal cell 40.

[0059] 6 shows the electrode arrangement, the alignment direction (arrows) of the alignment film, and the initial alignment of the liquid crystal molecules in the first liquid crystal cell 10, second liquid crystal cell 20, third liquid crystal cell 30, and fourth liquid crystal cell 40. The liquid crystal layer is made of positive liquid crystal, and in the initial state when no control signal is input to each liquid crystal cell, the long axis direction of the liquid crystal is aligned in a direction intersecting (perpendicular to) the strip electrodes. That is, the first liquid crystal cell 10, the second liquid crystal cell 20, the third liquid crystal cell 30, and the fourth liquid crystal cell 40 are arranged so that the alignment direction of the alignment film (first alignment film) on the first substrate S11, S21, S31, S41 side intersects with the extension direction of the first electrodes E11, E21, E31, E41 having a strip-shaped pattern, and the alignment direction of the alignment film (second alignment film) on the second substrate S12, S22, S32, S42 side intersects with the alignment direction of the alignment film (first alignment film) on the first substrate S11, S21, S31, S41 side.

[0060] 6, the alignment directions of the alignment films (not shown) on the first substrates S11, S21 of the first liquid crystal cell 10 and the second liquid crystal cell 20 are parallel to the X-axis direction, and the alignment directions of the alignment films (not shown) on the second substrates S12, S22 are parallel to the Y-axis direction. The extension directions of the strip-shaped patterns of the first electrodes E11, E21 of the first liquid crystal cell 10 and the second liquid crystal cell 20 are parallel to the Y-axis direction, and the second electrodes E12, E22 are planar (also referred to as flat or solid) electrodes that extend over at least the effective area (which refers to the area through which incident light passes, the same applies hereinafter). The alignment direction of the alignment film (not shown) on the first substrate S31, S41 side of the third liquid crystal cell 30 and the fourth liquid crystal cell 40 is parallel to the Y-axis direction, and the alignment direction of the alignment film (not shown) on the second substrate S32, S42 side is parallel to the X-axis direction. The extension direction of the strip-shaped patterns of the first electrodes E31, E41 of the third liquid crystal cell 30 and the fourth liquid crystal cell 40 is parallel to the X-axis direction, and the second electrodes E32, E42 are planar (also referred to as flat or solid) electrodes that extend at least over the effective area. According to the definitions of the X-axis and Y-axis directions, the alignment directions of the alignment film intersect at an angle of 90 degrees on the first substrate side and the second substrate side of each liquid crystal cell, but the intersection angle can be set within a range of 90±10 degrees.

[0061] In the following description, the polarization direction of the first polarized component PL1 is defined as the X-axis direction, and the polarization direction of the second polarized component PL2 is defined as the Y-axis direction. For example, the first polarized component PL1 is an S-wave, and the second polarized component PL2 is a P-wave. In addition, "Diffusion (X)" in the table of FIG. 6 indicates that the polarized component is diffused in the X-axis direction, and "Diffusion (Y)" indicates that the polarized component is diffused in the Y-axis direction.

[0062] In Figure 6, hatching indicates electrodes to which control signals are applied to form a transverse electric field. A table is also inserted into Figure 6, showing the states of each polarization component when light containing a first polarization component PL1 and a second polarization component PL2 passes through the first electrode, liquid crystal layer, and second electrode of each liquid crystal cell. The terms "transmission," "optical rotation," and "diffusion" are used to indicate this state. Here, "transmission" indicates that the polarization component passes through the liquid crystal cell without being diffused or rotated. "Diffusion" indicates that the polarization component is diffused and transmitted due to the refractive index distribution of the liquid crystal molecules. Therefore, for example, "transmission" at the first electrode in the diagram indicates that the "transmission" phenomenon occurs near the first electrode in the liquid crystal layer. In the following description, "optical rotation" at the liquid crystal layer indicates that the polarization direction of the polarization component shifts by 90 degrees as it passes through the liquid crystal layer from the first substrate side to the second substrate side.

[0063] The liquid crystal light control element 102 according to the first configuration has a first liquid crystal cell 10, a second liquid crystal cell 20, a third liquid crystal cell 30, and a fourth liquid crystal cell 40 arranged in this order from the light incident side to the light emitting side. The light incident on the liquid crystal light control element 102 includes a first polarization component PL1 and a second polarization component PL2 that is orthogonal to the first polarization component PL1.

[0064] 6, the first electrode E11 of the first liquid crystal cell 10 and the first electrode E21 of the second liquid crystal cell 20 are arranged such that the extension direction of the strip electrodes is the same, so that the first liquid crystal cell 10 can diffuse the first polarized component PL1 in the X-axis direction, and the second liquid crystal cell 20 can diffuse the second polarized component PL2 in the X-axis direction. In addition, the second electrode E32 of the third liquid crystal cell 30 and the second electrode E42 of the fourth liquid crystal cell 40 are arranged such that the extension direction is the same, so that the third liquid crystal cell 30 can diffuse the second polarized component PL2 in the Y-axis direction, and the fourth liquid crystal cell 40 can diffuse the first polarized component PL1 in the Y-axis direction.

[0065] A control signal is input to each liquid crystal cell to control the polarization and diffusion state of light incident on the liquid crystal light control element 102. FIG. 7 shows an example of the waveform of a control signal applied to the electrode of each liquid crystal cell. One of the control signals A, B, and E shown in FIG. 7 is input to each liquid crystal cell. In the control signals A and B, VL1 denotes a low-level voltage, and VH1 denotes a high-level voltage. For example, VL1 is a voltage of 0 V or −15 V, and VH1 is 30 V (relative to 0 V) ​​or 15 V (relative to −15 V). The control signals A and B are synchronized; when the control signal A is at the VL1 level, the control signal B is at the VH1 level. When the control signal A changes to the VH1 level, the control signal B changes to the VL1 level. The cycle of the control signals A and B is approximately 15 to 100 Hz. On the other hand, the control signal E is a constant voltage signal. For example, the control signal E is an intermediate voltage between VL1 and VH1, and when VL1=-15V and VH1=+15V, VE=0V.

[0066] Light is incident on the liquid crystal light control element 102 from a light source (not shown). The light emitted from the light source is preferably collimated light. The liquid crystal light control element 102 can control the profile (intensity distribution) of the light distribution pattern of light emitted from a light source (not shown) by selecting a control signal to be applied to each liquid crystal cell. Specifically, it can control the profile of the illumination light in the polar angle direction.

[0067] Table 1 shows the control signals applied to each liquid crystal cell of the liquid crystal light control element 102 shown in Fig. 6. Note that the control signals A, B, and E shown in Table 1 correspond to the control signals shown in Fig. 7. [Table 1]

[0068] As shown in Table 1, control signals are input to each liquid crystal cell of the liquid crystal light control element 102. Control signal A is input to the first strip electrode E11A of the first liquid crystal cell 10, control signal B is input to the second strip electrode E11B, and control signal E is input to the second electrode E12, and a transverse electric field is generated only on the first electrode E11 side. As shown in Table 1, the same is true for the second liquid crystal cell 20, the third liquid crystal cell 30, and the fourth liquid crystal cell 40. That is, in the liquid crystal light control element 102 shown in FIG. 6, control signals A and B are applied to the first electrode of each liquid crystal cell, and control signal E is applied to the second electrode, and a transverse electric field is generated only on the first substrate side.

[0069] When the liquid crystal light control element 102 is in operation, the control signals shown in Table 1 are input to the strip electrodes of each liquid crystal cell. When the control signals shown in Table 1 are input to the first liquid crystal cell 10, the second liquid crystal cell 20, the third liquid crystal cell 30, and the fourth liquid crystal cell 40, the liquid crystal molecules on the first substrate side of each liquid crystal cell are affected by the lateral electric field and the alignment state changes, as shown in Fig. 4C.

[0070] Next, the operation of the liquid crystal light control element 102 will be described in terms of the effect that each liquid crystal cell has on incident light. Here, the incident light includes two polarization components: a first polarization component PL1 and a second polarization component PL2. The first polarization component PL1 and the second polarization component PL2 are linearly polarized polarization components, and have either s-polarized or p-polarized polarization. These polarization states can transition from s-polarized to p-polarized or p-polarized to s-polarized by optical rotation within the liquid crystal layer. It is assumed that the first polarization component PL1 is s-polarized and the second polarization component PL2 is p-polarized immediately before the light enters the liquid crystal light control element 102.

[0071] In FIG. 6, attention is focused on the first polarization component PL1. The first polarization component PL1 is incident on the first liquid crystal cell 10 in an s-polarized state. The polarization direction of the first polarization component PL1 (s-polarized light) is along the X-axis direction, which is parallel to the orientation direction of the long axes of the liquid crystal molecules on the first substrate S11 side of the first liquid crystal layer LC1. On the first substrate S11 side, the liquid crystal molecules are oriented under the influence of the transverse electric field generated by the first electrode E11, and an arc-shaped refractive index distribution is formed in the first liquid crystal layer LC1. The first polarization component PL1 (s-polarized light) incident on the first liquid crystal layer LC1 from the first substrate S11 is diffused in the X-axis direction under the influence of the arc-shaped refractive index distribution of the first liquid crystal layer LC1. As the first polarization component PL1 (s-polarized light) travels through the first liquid crystal layer LC1 from the first substrate S11 side to the second substrate S12 side, it is rotated by 90 degrees in accordance with the twisted orientation of the liquid crystal molecules. As a result, the first polarization component PL1 transitions from s-polarized light to p-polarized light. Since the second electrode E12 is a planar (also referred to as a flat or solid) electrode and has a constant potential across its entire surface, no arc-shaped refractive index distribution is formed in the liquid crystal molecules on the second substrate S12 side of the first liquid crystal layer LC1. As a result, the first polarization component PL1 (p-polarized light) is not diffused and is emitted directly from the second substrate S12. In this way, the first polarization component PL1 enters the first liquid crystal cell 10 as s-polarized light, is diffused in the X-axis direction, and is rotated by 90 degrees to be emitted from the first liquid crystal cell 10 as p-polarized light.

[0072] The first polarized light component PL1 that passes through the first liquid crystal cell 10 enters the second liquid crystal cell 20 as p-polarized light. The polarization direction of the first polarized light component PL1 (p-polarized light) is along the Y-axis direction, which intersects with the orientation direction of the long axes of the liquid crystal molecules on the first substrate S21 side of the second liquid crystal layer LC2. On the first substrate S21 side, the liquid crystal molecules are oriented under the influence of the transverse electric field generated by the first electrode E21, forming an arc-shaped refractive index distribution in the second liquid crystal layer LC2. However, the first polarized light component PL1 (p-polarized light) is not diffused and travels directly toward the second substrate S22. As the first polarized light component PL1 (p-polarized light) travels through the second liquid crystal layer LC2 from the first substrate S21 side to the second substrate S22 side, it is rotated by 90 degrees in accordance with the twisted orientation of the liquid crystal molecules. As a result, the first polarized light component PL1 transitions from p-polarized light to s-polarized light. Since the second electrode E22 is a planar (also referred to as a flat or solid) electrode and has a constant potential over its entire surface, no arc-shaped refractive index distribution is formed in the liquid crystal molecules on the second substrate S22 side of the second liquid crystal layer LC2. As a result, the first polarization component PL1 (s-polarized light) is not diffused and is emitted directly from the second substrate S22. In this way, the first polarization component PL1 enters the second liquid crystal cell 20 as p-polarized light, is rotated by 90 degrees without being diffused, and is emitted from the second liquid crystal cell 20 as s-polarized light.

[0073] The first polarized light component PL1, which has passed through the second liquid crystal cell 20, enters the third liquid crystal cell 30 as s-polarized light. In the third liquid crystal cell 30, the extension direction of the strip electrodes (E31A, E31B) of the first electrode E31 is perpendicular to the extension direction of the strip electrodes (E11A, E11B, E21A, E21B) of the first electrodes E11, E21 of the first liquid crystal cell 10 and the second liquid crystal cell 20. The polarization direction of the first polarized light component PL1 (s-polarized light) is along the X-axis direction, which is perpendicular to the alignment direction of the long axes of the liquid crystal molecules on the first substrate S31 side of the third liquid crystal layer LC3. On the first substrate S31 side, the liquid crystal molecules are oriented by the influence of the transverse electric field generated by the first electrode E31, forming an arc-shaped refractive index distribution in the third liquid crystal layer LC3. However, the first polarized light component PL1 (s-polarized light) is not diffused and travels directly toward the second substrate S32. The first polarization component PL1 (s-polarized light) is rotated by 90 degrees in accordance with the twisted orientation of the liquid crystal molecules as it travels through the third liquid crystal layer LC3 from the first substrate S31 side to the second substrate S32 side. This causes the first polarization component PL1 to transition from s-polarized light to p-polarized light. Because the second electrode E32 is a planar (also referred to as a flat or solid) electrode and has a constant potential across its entire surface, no arc-shaped refractive index distribution is formed in the liquid crystal molecules on the second substrate S32 side of the third liquid crystal layer LC3. Therefore, the first polarization component PL1 (p-polarized light) is not diffused and exits the second substrate S32 as is. In this way, the first polarization component PL1 enters the third liquid crystal cell 30 as s-polarized light, is rotated by 90 degrees without being diffused, and exits the third liquid crystal cell 30 as p-polarized light.

[0074] The first polarized light component PL1 that passes through the third liquid crystal cell 30 enters the fourth liquid crystal cell 40 as p-polarized light. The first electrode E41 of the fourth liquid crystal cell 40 is oriented in the same direction as the first electrode E31 of the third liquid crystal cell 30. Therefore, the long axis alignment direction of the liquid crystal molecules on the first substrate S41 side of the fourth liquid crystal cell 40 is also the same as that of the third liquid crystal cell 30. The polarization direction of the first polarized light component PL1 (p-polarized light) is along the Y-axis direction, which is parallel to the long axis alignment direction of the liquid crystal molecules on the first substrate S41 side of the fourth liquid crystal layer LC4. On the first substrate S41 side, the liquid crystal molecules are oriented under the influence of the transverse electric field generated by the first electrode E41, and an arc-shaped refractive index distribution is formed in the fourth liquid crystal layer LC4. The first polarized light component PL1 (p-polarized light) that enters the fourth liquid crystal layer LC4 from the first substrate S41 is diffused in the Y-axis direction under the influence of the arc-shaped refractive index distribution of the fourth liquid crystal layer LC4. The first polarization component PL1 (p-polarized light) is rotated by 90 degrees in accordance with the twisted orientation of the liquid crystal molecules as it travels through the fourth liquid crystal layer LC4 from the first substrate S41 side to the second substrate S42 side. This causes the first polarization component PL1 to transition from p-polarized light to s-polarized light. Because the second electrode E42 is a planar (also referred to as a flat or solid) electrode and has a constant potential across its entire surface, no arc-shaped refractive index distribution is formed in the liquid crystal molecules on the second substrate S42 side of the fourth liquid crystal layer LC4. Therefore, the first polarization component PL1 (s-polarized light) is not diffused and is emitted directly from the second substrate S42. In this way, the first polarization component PL1 enters the fourth liquid crystal cell 40 as p-polarized light, is diffused in the Y-axis direction, is rotated by 90 degrees, and exits the fourth liquid crystal cell 40 as s-polarized light.

[0075] In this way, the first polarization component PL1 incident on the liquid crystal light control element 102 is diffused once in the X-axis direction and once in the Y-axis direction between when it enters the first liquid crystal cell 10 and when it exits the fourth liquid crystal cell 40, and it enters in an s-polarized state and is rotated four times at an angle of 90 degrees, thereby exiting in an s-polarized state.

[0076] Next, we will focus on the second polarization component PL2. The second polarization component PL2 is incident on the first liquid crystal cell 10 as p-polarized light. The polarization direction of the second polarization component PL2 (p-polarized light) is along the Y-axis direction, which is a direction intersecting the orientation direction of the long axes of the liquid crystal molecules on the first substrate S11 side of the first liquid crystal layer LC1. Although an arc-shaped refractive index distribution is formed in the first liquid crystal layer LC1 on the first substrate S11 side, the second polarization component PL2 (p-polarized light) is not diffused and travels directly toward the second substrate S12. As the first polarization component PL1 (p-polarized light) travels through the first liquid crystal layer LC1 from the first substrate S11 side to the second substrate S12 side, it is rotated by 90 degrees in accordance with the twisted orientation of the liquid crystal molecules. As a result, the first polarization component PL1 transitions from p-polarized light to s-polarized light. On the second substrate S12 side, the planar (also referred to as flat or solid) second electrode E12 is at a constant potential, so that an arc-shaped refractive index distribution is not formed in the first liquid crystal layer LC1, and the second polarization component PL2 (s-polarized light) is emitted from the second substrate S12 without being diffused. In this way, the second polarization component PL2 enters the first liquid crystal cell 10 in a p-polarized state, is rotated by 90 degrees without being diffused, and is emitted from the first liquid crystal cell 10 in an s-polarized state.

[0077] The second polarized light component PL2 that passes through the first liquid crystal cell 10 enters the second liquid crystal cell 20 as s-polarized light. The polarization direction of the second polarized light component PL2 (s-polarized light) is along the X-axis direction, which is parallel to the alignment direction of the long axes of the liquid crystal molecules on the first substrate S21 side of the second liquid crystal layer LC2. On the first substrate S21 side, the second liquid crystal layer LC2 has an arc-shaped refractive index distribution. The second polarized light component PL2 (s-polarized light) that enters the second liquid crystal layer LC2 from the first substrate S21 is affected by the arc-shaped refractive index distribution of the second liquid crystal layer LC2 and is diffused in the X-axis direction. As the second polarized light component PL2 (s-polarized light) travels through the second liquid crystal layer LC2 from the first substrate S21 side to the second substrate S22 side, it is rotated by 90 degrees in accordance with the twisted alignment of the liquid crystal molecules. As a result, the second polarized light component PL2 transitions from s-polarized light to p-polarized light. Since the second electrode E22 is a planar (also referred to as a flat or solid) electrode and has a constant potential across its entire surface, no arc-shaped refractive index distribution is formed in the liquid crystal molecules on the second substrate S22 side of the second liquid crystal layer LC2. As a result, the second polarization component PL2 (p-polarized light) is not diffused and is emitted directly from the second substrate S22. In this way, the second polarization component PL2 enters the second liquid crystal cell 20 as s-polarized light, is diffused in the X-axis direction, and is rotated by 90 degrees to be emitted from the second liquid crystal cell 20 as p-polarized light.

[0078] The second polarized light component PL2 that passes through the second liquid crystal cell 20 enters the third liquid crystal cell 30 as p-polarized light. The polarization direction of the second polarized light component PL2 (p-polarized light) is along the Y-axis direction, which is parallel to the alignment direction of the long axes of the liquid crystal molecules on the first substrate S31 side of the third liquid crystal layer LC3. On the first substrate S31 side, the third liquid crystal layer LC3 has an arc-shaped refractive index distribution. The second polarized light component PL2 (p-polarized light) that enters the third liquid crystal layer LC3 from the first substrate S31 is affected by the arc-shaped refractive index distribution of the third liquid crystal layer LC3 and is diffused in the Y-axis direction. As the second polarized light component PL2 (p-polarized light) travels through the third liquid crystal layer LC3 from the first substrate S31 side to the second substrate S32 side, it is rotated by 90 degrees in accordance with the twisted alignment of the liquid crystal molecules. As a result, the second polarized light component PL2 transitions from p-polarized light to s-polarized light. Since the second electrode E32 is a planar (also referred to as a flat or solid) electrode and has a constant potential across its entire surface, no arc-shaped refractive index distribution is formed in the liquid crystal molecules on the second substrate S32 side of the third liquid crystal layer LC3. As a result, the second polarization component PL2 (s-polarized light) is not diffused and is emitted directly from the second substrate S32. In this way, the second polarization component PL2 enters the third liquid crystal cell 30 as p-polarized light, is diffused in the Y-axis direction, and is rotated 90 degrees to exit the third liquid crystal cell 30 as s-polarized light.

[0079] The second polarized light component PL2 that passes through the third liquid crystal cell 30 enters the fourth liquid crystal cell 40 as s-polarized light. The polarization direction of the second polarized light component PL2 (s-polarized light) is along the X-axis direction, which is a direction that intersects with the orientation direction of the long axes of the liquid crystal molecules on the first substrate S31 side of the third liquid crystal layer LC3. Although an arc-shaped refractive index distribution is formed in the fourth liquid crystal layer LC4 on the first substrate S41 side, the second polarized light component PL2 (s-polarized light) is not diffused and travels directly to the second substrate S42. As the second polarized light component PL2 (s-polarized light) travels through the fourth liquid crystal layer LC4 from the first substrate S41 side to the second substrate S42 side, it is rotated by 90 degrees in accordance with the twisted orientation of the liquid crystal molecules. As a result, the second polarized light component PL2 transitions from s-polarized light to p-polarized light. Since the second electrode E42 is a planar (also referred to as a flat or solid) electrode and has a constant potential across its entire surface, no arc-shaped refractive index distribution is formed in the liquid crystal molecules on the second substrate S42 side of the fourth liquid crystal layer LC4. As a result, the second polarization component PL2 (p-polarized light) is not diffused and is emitted directly from the second substrate S42. In this way, the second polarization component PL2 enters the fourth liquid crystal cell 40 as s-polarized light, is rotated 90 degrees without being diffused, and is emitted from the fourth liquid crystal cell 40 as p-polarized light.

[0080] The second polarized component PL2 incident on the liquid crystal light control element 102 is diffused once in the X-axis direction and once in the Y-axis direction between when it enters the first liquid crystal cell 10 and when it exits the fourth liquid crystal cell 40, and is then incident in a p-polarized state and rotated four times at an angle of 90 degrees, thereby exiting in a p-polarized state.

[0081] In the first configuration, the first polarization component PL1 is diffused in the X-axis direction before being rotated by the first liquid crystal cell 10 and in the Y-axis direction before being rotated by the fourth liquid crystal cell 40, and the second polarization component PL2 is diffused in the X-axis direction before being rotated by the second liquid crystal cell 20 and in the Y-axis direction before being rotated by the third liquid crystal cell 30. Here, if the diffusion of a polarization component before being rotated by each liquid crystal cell is referred to as pre-diffusion and the diffusion after being rotated is referred to as post-diffusion, in the first configuration, the first polarization component PL1 is pre-diffused once in the X-axis direction and once in the Y-axis direction, and the second polarization component PL2 is pre-diffused once in the X-axis direction and once in the Y-axis direction. Furthermore, no post-diffusion occurs for any of the polarization components.

[0082] 1-1-1. Modification of the first configuration (1) Although FIG. 6 shows a configuration in which planar (also referred to as flat or solid) second electrodes (E12, E22, E32, E42) are provided in each liquid crystal cell, the liquid crystal light control element 102 according to the first configuration is not limited to this configuration. For example, as shown in FIG. 8, the second electrodes may be omitted from the second substrates (S12, S22, S32, S42) of the first to fourth liquid crystal cells, and only alignment films (not shown) may be provided. The alignment direction of the alignment film on the second substrate side is orthogonal (90°±10°) to the alignment direction of the alignment film on the first substrate side in each liquid crystal cell. Even with a configuration in which the second electrodes of each liquid crystal cell are omitted, the first polarization component PL1 and the second polarization component PL2 can be diffused in the same manner as the liquid crystal light control element 102 shown in FIG. 6.

[0083] 1-1-2. Modification of the first configuration (2) 9 shows a configuration in which strip electrodes (third strip electrodes E12A, E22A, E32A, E42A and fourth strip electrodes E12B, E22B, E32B, E42B) are provided instead of planar (also referred to as flat or solid) electrodes as the second electrodes (E12, E22, E32, E42) of the first to fourth liquid crystal cells. In this case, by applying a constant voltage such as the control signal E shown in FIG. 7 to the third strip electrodes E12A, E22A, E32A, E42A and the fourth strip electrodes E12B, E22B, E32B, E42B, it is possible to prevent the generation of a transverse electric field, and to obtain light distribution characteristics similar to those of the liquid crystal light control element 102 shown in FIG. 6.

[0084] 1-2. Second Configuration In the second configuration, the liquid crystal light control element does not diffuse the polarized light components on the first electrode E11, E41 side (light incident side) of the first liquid crystal cell 10 and the fourth liquid crystal cell 40, but diffuses them on the second electrode E12, E42 side (light exit side), and diffuses them on the first electrode E21, E31 side (light incident side) of the second liquid crystal cell 20 and the third liquid crystal cell 30, but does not diffuse them on the second electrode E22, E32 side (light exit side).

[0085] 10 shows a liquid crystal light control element 102 according to the second configuration. The liquid crystal light control element 102 according to the second configuration has first to fourth liquid crystal cells. The first liquid crystal cell 10 has a first electrode E11 (first strip electrode E11A, second strip electrode E11B) provided on a first substrate S11 and a second electrode E12 (third strip electrode E12A, fourth strip electrode E12B) provided on a second substrate S12. The second liquid crystal cell 20 has a first electrode E21 (first strip electrode E21A, second strip electrode E21B) provided on a first substrate S21 and a second electrode E22 (third strip electrode E22A, fourth strip electrode E22B) provided on a second substrate S22. The third liquid crystal cell 30 has a first electrode E31 (first strip electrode E31A, second strip electrode E31B) on the first substrate S31 and a second electrode E32 (third strip electrode E32A, fourth strip electrode E32B) on the second substrate S32, and the fourth liquid crystal cell 40 has a first electrode E41 (first strip electrode E41A, second strip electrode E41B) on the first substrate S41 and a second electrode E42 (third strip electrode E42A, fourth strip electrode E42B) on the second substrate S42.

[0086] Table 2 shows the control signals applied to each liquid crystal cell of the liquid crystal light control element 102 shown in Fig. 10. In Fig. 10, strip electrodes to which a control signal is applied and which generate a transverse electric field are shown hatched, and strip electrodes to which no control signal is applied and which do not generate a transverse electric field are shown white. Note that control signals A and B shown in Table 3 correspond to the control signals shown in Fig. 7. [Table 2]

[0087] As shown in Table 2, a control signal E is input to the first strip electrode E11A and the second strip electrode E11B of the first liquid crystal cell 10, a control signal A is input to the third strip electrode E12A, and a control signal B is input to the fourth strip electrode E12B. The same applies to the fourth liquid crystal cell 40. In the second liquid crystal cell 20, a control signal A is applied to the first strip electrode E21A, a control signal B is input to the second strip electrode E21B, and a control signal E is input to the third strip electrode E22A and the fourth strip electrode E22B. The same applies to the third liquid crystal cell 30. That is, in the liquid crystal light control element 102 shown in FIG. 10, control signals are input so that a transverse electric field is not generated on the first substrate side but is generated on the second substrate side in the first liquid crystal cell 10 and the fourth liquid crystal cell 40, and a transverse electric field is generated on the first substrate side but is not generated on the second substrate side in the second liquid crystal cell 20 and the third liquid crystal cell 30.

[0088] Next, the operation of the liquid crystal light control element 102 according to the second configuration will be described in terms of the effect that each liquid crystal cell has on incident light.

[0089] In FIG. 10, attention is focused on the first polarization component PL1. The first polarization component PL1 enters the first liquid crystal cell 10 as s-polarized light. The first electrode E11 of the first liquid crystal cell 10 does not generate a transverse electric field. Therefore, the first polarization component PL1 is not diffused by the first electrode E11. Instead, as it travels through the first liquid crystal layer LC1 from the first substrate S11 side to the second substrate S12 side, it is rotated by 90 degrees in accordance with the twisted orientation of the liquid crystal molecules and transitions to p-polarized light. In the second electrode E12, a control signal A is applied to the third strip-shaped electrode E12A, and a control signal B is applied to the fourth strip-shaped electrode E12B, generating a transverse electric field. Therefore, an arc-shaped refractive index distribution is formed on the second substrate S12 side of the first liquid crystal layer LC1. Because the polarization direction of the first polarization component PL1 (p-polarized light) is parallel to the long axis of the liquid crystal molecules, it is diffused in the Y-axis direction due to the influence of the arc-shaped refractive index distribution and exits from the second substrate S12. In this way, the first polarization component PL1 enters the first liquid crystal cell 10 in an s-polarized state, is rotated by 90 degrees to become p-polarized, and is diffused in the Y-axis direction before exiting the first liquid crystal cell 10.

[0090] The first polarized light component PL1 that has passed through the first liquid crystal cell 10 is incident on the second liquid crystal cell 20 in a p-polarized state. As in the first embodiment, the first polarized light component (p-polarized light) that has entered the second liquid crystal cell 20 is not diffused, but is rotated by 90 degrees and exits from the second liquid crystal cell 20 in an s-polarized state.

[0091] The first polarized light component PL1 that has passed through the second liquid crystal cell 20 is incident on the third liquid crystal cell 30 in an s-polarized state. As in the first embodiment, the first polarized light component (s-polarized light) that has entered the third liquid crystal cell 30 is not diffused, but is rotated by 90 degrees and exits from the third liquid crystal cell 30 in a p-polarized state.

[0092] The first polarized light component PL1 that passes through the third liquid crystal cell 30 enters the fourth liquid crystal cell 40 as p-polarized light. The first electrode E41 of the fourth liquid crystal cell 40 does not generate a transverse electric field. Therefore, the first polarized light component PL1 is not diffused by the first electrode E41, and is rotated by 90 degrees in accordance with the twisted orientation of the liquid crystal molecules as it travels through the fourth liquid crystal layer LC4 from the first substrate S41 side to the second substrate S42 side, resulting in transition to s-polarized light. In the second electrode E42, a transverse electric field is generated because control signal A is applied to the third strip-shaped electrode E42A and control signal B is applied to the fourth strip-shaped electrode E42B. Therefore, an arc-shaped refractive index distribution is formed on the second substrate S42 side of the fourth liquid crystal layer LC4. Because the polarization direction of the first polarized light component PL1 (s-polarized light) is parallel to the long axes of the liquid crystal molecules, it is diffused in the X-axis direction due to the influence of the arc-shaped refractive index distribution and exits from the second substrate S42. In this way, the first polarization component PL1 enters the fourth liquid crystal cell 40 in a p-polarized state, is rotated by 90 degrees to become an s-polarized state, is diffused in the X-axis direction, and exits the fourth liquid crystal cell 40.

[0093] The first polarization component PL1 incident on the liquid crystal light control element 102 of the second configuration is diffused once in the X-axis direction and once in the Y-axis direction from the time it enters the first liquid crystal cell 10 until it exits the fourth liquid crystal cell 40, and is incident in an s-polarized state and rotated four times at an angle of 90 degrees, thereby exiting in an s-polarized state.

[0094] Next, we will focus on the second polarization component PL2. The second polarization component PL2 enters the first liquid crystal cell 10 in a p-polarized state. The first electrode E11 of the first liquid crystal cell 10 does not generate a transverse electric field. Therefore, the second polarization component PL2 (p-polarized) is not diffused by the first electrode E11, and is rotated by 90 degrees in accordance with the twisted orientation of the liquid crystal molecules as it travels through the first liquid crystal layer LC1 from the first substrate S11 side to the second substrate S12 side, transitioning to s-polarized light. The second polarization component PL2 (s-polarized) is not diffused by the second electrode E12 and exits the first liquid crystal cell 10 in an s-polarized state.

[0095] The second polarized component PL2 that passed through the first liquid crystal cell 10 enters the second liquid crystal cell 20 in an s-polarized state. In the second liquid crystal cell 20, the second polarized component PL2 (s-polarized) is diffused in the X-axis direction on the first substrate S21 side, as in the first configuration. The second polarized component PL2 (s-polarized) is rotated by 90 degrees in accordance with the twisted orientation of the liquid crystal molecules as it travels through the second liquid crystal layer LC2 from the first substrate S21 side to the second substrate S22 side. As a result, the second polarized component PL2 transitions from s-polarized to p-polarized. The second electrode E22 of the second liquid crystal cell 20 does not generate a transverse electric field. Therefore, the second polarized component PL2 is not diffused by the second electrode E22 and exits the second liquid crystal cell 20 in a p-polarized state.

[0096] The second polarized light component PL2 that passed through the second liquid crystal cell 20 enters the third liquid crystal cell 30 in a p-polarized state. In the third liquid crystal cell 30, the second polarized light component PL2 (p-polarized light) is diffused in the Y-axis direction on the first substrate S31 side, as in the first configuration. The second polarized light component PL2 (p-polarized light) is rotated by 90 degrees in accordance with the twisted orientation of the liquid crystal molecules as it travels through the third liquid crystal layer LC3 from the first substrate S31 side to the second substrate S32 side. This causes the second polarized light component PL2 to transition from p-polarized light to s-polarized light. The second electrode E32 of the third liquid crystal cell 30 does not generate a transverse electric field. Therefore, the second polarized light component PL2 is not diffused by the second electrode E32 and exits the third liquid crystal cell 30 in an s-polarized state.

[0097] The second polarization component PL2 that passes through the third liquid crystal cell 30 enters the fourth liquid crystal cell 40 in an s-polarized state. The first electrode E41 of the fourth liquid crystal cell 40 does not generate a transverse electric field. Therefore, the second polarization component PL2 (s-polarized) is not diffused by the first electrode E11, and is rotated by 90 degrees in accordance with the twisted orientation of the liquid crystal molecules as it travels through the first liquid crystal layer LC1 from the first substrate S11 side to the second substrate S12 side, thereby transitioning to p-polarized light. The second polarization component PL2 (p-polarized) is then emitted from the fourth liquid crystal cell 40 without being diffused by the second substrate S42.

[0098] The second polarization component PL2 incident on the liquid crystal light control element 102 of the second configuration is diffused once in the X-axis direction and once in the Y-axis direction from the time it enters the first liquid crystal cell 10 until it exits the fourth liquid crystal cell 40, and enters in a p-polarized state and is rotated four times at an angle of 90 degrees, thereby exiting in a p-polarized state.

[0099] In the second configuration, the first polarization component PL1 is diffused in the Y-axis direction after being rotated by the first liquid crystal cell 10, and is diffused in the X-axis direction after being rotated by the fourth liquid crystal cell 40. The second polarization component PL2 is diffused in the X-axis direction before being rotated by the second liquid crystal cell 20, and is diffused in the Y-axis direction before being rotated by the third liquid crystal cell 30. That is, in the second configuration, the first polarization component PL1 is pre-diffused 0 times in the X-axis direction and post-diffused 1 time, and pre-diffused 0 times in the Y-axis direction and post-diffused 1 time. Also, the second polarization component PL2 is pre-diffused 1 time in the X-axis direction and post-diffused 0 times, and pre-diffused 1 time in the Y-axis direction and post-diffused 0 times.

[0100] 1-3. Reference example 1 11 shows a liquid crystal light control element according to Reference Example 1. In Reference Example 1, a control signal A is applied to the first strip electrode E11A on the first substrate S11 side of the first liquid crystal cell 10, a control signal B is applied to the second strip electrode E11B, a control signal A is applied to the third strip electrode E12A on the second substrate S12 side, and a control signal B is applied to the fourth strip electrode E12B. The same is true for the second liquid crystal cell 20, the third liquid crystal cell 30, and the fourth liquid crystal cell 40. That is, in each liquid crystal cell, a transverse electric field is generated on both the first substrate (S11, S21, S31, S41) side and the second substrate (S12, S22, S32, S42) side.

[0101] 11, focusing on the first polarization component PL1, the first polarization component PL1 enters the first liquid crystal cell 10 in an s-polarized state. The first polarization component PL1 is diffused in the X-axis direction on the first electrode E11 side of the first liquid crystal cell 10, rotated by 90 degrees in the first liquid crystal layer LC1, and diffused in the Y-axis direction on the second electrode E12 side. The first polarization component PL1 is rotated by 90 degrees by each of the second liquid crystal cell 20 and the third liquid crystal cell 30 while passing through, diffused in the Y-axis direction on the first electrode E41 side of the fourth liquid crystal cell 40, rotated by 90 degrees in the fourth liquid crystal layer LC4, and diffused in the X-axis direction on the second electrode E42 side, and exits in an s-polarized state.

[0102] 11, focusing on the second polarized component PL2, the second polarized component PL2 enters the first liquid crystal cell 10 in a p-polarized state. The second polarized component PL2 is rotated by 90 degrees by the first liquid crystal cell 10 and enters the second liquid crystal cell 20 in an s-polarized state without being diffused by the first liquid crystal cell 10. The second polarized component PL2 is diffused in the X-axis direction on the first electrode E21 side of the second liquid crystal cell 20, rotated by 90 degrees by the second liquid crystal layer LC2 to become p-polarized, and diffused in the Y-axis direction on the second electrode E22 side. The second polarized component PL2 is then diffused in the Y-axis direction on the first electrode E31 side of the third liquid crystal cell 30, rotated by 90 degrees by the third liquid crystal layer LC3 to become s-polarized, and diffused in the X-axis direction on the second electrode E22 side. The second polarized component PL2 is then rotated by 90 degrees by the fourth liquid crystal cell 40 and exits in a p-polarized state without being diffused by the fourth liquid crystal cell 40.

[0103] In this way, in the liquid crystal light control element of Reference Example 1, the first polarization component PL1 is diffused in the X-axis and Y-axis directions by the first liquid crystal cell 10 and the fourth liquid crystal cell 40, and the second polarization component PL2 is diffused in the X-axis and Y-axis directions by the second liquid crystal cell 20 and the third liquid crystal cell 30.

[0104] 1-4.Angular characteristics FIG. 12A shows a graph of the luminance-angle characteristics of the liquid crystal light control element 102 according to the first and second configurations. The graph also shows the characteristics of Reference Example 1. The horizontal axis of the graph shown in FIG. 12A indicates the polar angle. As shown in FIG. 12E, the polar angle shown in the graph indicates angles tilted in the positive and negative directions toward the X-axis, with 0 degrees indicating the angle when the light-emitting surface of the liquid crystal light control element 102 is viewed directly from the front. The vertical axis of the graph indicates the luminance normalized with the luminance at the center (polar angle 0 degrees) set to 100%.

[0105] 12A, the characteristics of the first configuration of liquid crystal light control element 102 show that, although the luminance in the polar angle ranges of +20 to +40 degrees and -20 to -40 degrees drops by about 20% from the center luminance, a constant luminance distribution is obtained within the same range. In the first configuration, as described above, by adopting a configuration in which each polarized component is diffused before being rotated by the liquid crystal layer and not diffused after being rotated, a substantially flat intensity distribution can be obtained within a certain range of polar angles. In other words, by preventing the components of the polarized components diffused in a predetermined direction (X-axis or Y-axis) by the liquid crystal cell that are not fully rotated by the liquid crystal layer from being diffused again by the electrode on the light-exiting side, a flat luminance angular characteristic can be obtained.

[0106] Note that the above phrase "each polarization component is diffused before being rotated in the liquid crystal layer and not diffused after being rotated" refers to a polarization component being diffused before being rotated in a certain liquid crystal panel and not being further diffused after being rotated in the same liquid crystal panel immediately thereafter, but does not include a polarization component being diffused in a different liquid crystal panel as it passes through the liquid crystal light control element. For example, in the first configuration above, the first polarization component is diffused in the first liquid crystal cell and the fourth liquid crystal cell, but in the first liquid crystal cell it is diffused before being rotated (pre-diffusion) and not diffused after being rotated, and in the fourth liquid crystal cell it is similarly diffused before being rotated and not diffused after being rotated.

[0107] It can be seen that the characteristics of the second configuration of the liquid crystal light control element 102 achieve a constant luminance distribution within the polar angle ranges of +20 to +40 degrees and -20 to -40 degrees, although the luminance drops by about 40% from the center luminance within these ranges. In the second configuration, the first polarized component PL1 is diffused after the optical rotation in the liquid crystal layer, and the second polarized component PL2 is diffused before the optical rotation. The characteristics of the second configuration achieve a profile similar to that of the first configuration, although the luminance drops within the polar angle ranges of +20 to +40 degrees and -20 to -40 degrees. As can be seen, by diffusing each polarized component once in the X-axis direction and once in the Y-axis direction, a relatively flat luminance characteristic can be achieved within the polar angle ranges of +20 to +40 degrees and -20 to -40 degrees.

[0108] Thus, when comparing the first and second configurations, in the first configuration, both the first and second polarization components are pre-diffused once in the X-axis direction as they pass through the liquid crystal light control element 102, whereas in the second configuration, the first polarization component is post-diffused once in the X-axis direction and the second polarization component is pre-diffused once in the X-axis direction, which shows that pre-diffusion suppresses brightness reduction more than post-diffusion and maintains a constant brightness over a wider polar angle range.

[0109] In contrast, the characteristics of the liquid crystal light control element shown in Reference Example 1 show that the luminance intensity distribution is greatest at a polar angle of 0 degrees and tends to decrease linearly as the polar angle increases in the positive and negative directions (i.e., left and right directions). It can be seen that the liquid crystal light control element of Reference Example 1 has a different characteristic in terms of the change in luminance in the polar angle direction from the characteristics of the first and second configurations by diffusing each polarized component in front of and behind the liquid crystal layer. In other words, it can be seen that a luminance distribution that decreases linearly in the polar angle direction is obtained by diffusing the polarized components in front of and behind the optical rotation in the liquid crystal cell.

[0110] More specifically, in Reference Example 1, the first polarized component is pre-diffused once in the X-axis direction, but is then post-diffused in the Y-axis direction within the same liquid crystal cell (first liquid crystal cell) immediately after the pre-diffusion. The second polarized component is pre-diffused once in the X-axis direction, but is then post-diffused in the Y-axis direction within the same liquid crystal cell (second liquid crystal cell) immediately before the post-diffusion. Furthermore, in Reference Example 1, the first polarized component is pre-diffused once in the Y-axis direction, but is then post-diffused in the X-axis direction within the same liquid crystal cell (fourth liquid crystal cell) immediately after the pre-diffusion. The second polarized component is pre-diffused once in the Y-axis direction, but is then post-diffused in the X-axis direction within the same liquid crystal cell (third liquid crystal cell) immediately after the pre-diffusion. In other words, in Reference Example 1, each polarized component is pre-diffused once in the X-axis direction and post-diffused once, but both are accompanied by diffusion in the Y-axis direction within the same liquid crystal cell. Figure 12A shows that when diffusion occurs before and after optical rotation in the same liquid crystal cell, even if the number of pre-diffusions is the same, the brightness decreases monotonically as the polar angle increases compared to when diffusion is performed only by pre-diffusion (first configuration).

[0111] 12A, in all of the first configuration, the second configuration, and Reference Example 1, the luminance is half that at a polar angle of 0 degrees at around a polar angle of 50 degrees, and thereafter the luminance decreases in the same manner. If the region up to which this luminance is reduced to half is referred to as the half width, in the first configuration, the half width is the same as in Reference Example 1, but the luminance within the half width is improved compared to Reference Example 1 and kept constant, while in the second configuration, the half width is the same as in Reference Example 1, but the luminance within the half width is lower compared to Reference Example 1 and kept constant.

[0112] Next, the profiles of emitted light for each configuration are shown. FIG. 12B shows the profile of emitted light for the first configuration. In the first configuration, the first polarization component PL1 and the second polarization component PL2 are diffused once in the X-axis direction and once in the Y-axis direction by the electrodes on the light-incident side of each liquid crystal cell, resulting in a profile with a regular shape close to a square. FIG. 12C shows the profile of emitted light for the second configuration. In the second configuration, the first polarization component PL1 is diffused by the second substrates (substrates on the light-exiting side) of the first liquid crystal cell 10 and the fourth liquid crystal cell 40, and the second polarization component PL2 is diffused by the first substrates (substrates on the light-incident side) of the second liquid crystal cell 20 and the third liquid crystal cell 30, resulting in a profile that is close to a square, similar to the first configuration.

[0113] 12D shows the profile of the emitted light in Reference Example 1. In Reference Example 1, the first polarized component PL1 is diffused twice in the X-axis and Y-axis directions by the first liquid crystal cell 10 and the fourth liquid crystal cell 40, and the second polarized component PL2 is diffused twice in the X-axis and Y-axis directions by the second liquid crystal cell 20 and the third liquid crystal cell 30, resulting in a profile that is closer to a circle than the profiles obtained in the first and second configurations.

[0114] 12A, comparing the characteristics of the first and second configurations with those of Reference Example 1, it can be seen that the intensity of the light distribution is higher when the light is diffused on the first substrate (the substrate on the light incident side) side of each liquid crystal cell. On the other hand, as in Reference Example 1, by increasing the number of diffusion times, it is possible to reduce the decrease in brightness near the polar angle of 0 degrees.

[0115] 12B to 12D, it can be seen that a more regular (square) profile can be obtained by diffusing the polarized components in a single liquid crystal cell before optical rotation and not diffusing them after optical rotation, rather than diffusing them both before and after optical rotation by the liquid crystal layer. It can also be seen that a more regular (square) profile can be obtained by diffusing the polarized components in a single liquid crystal cell only before optical rotation by the liquid crystal layer or only after optical rotation by the liquid crystal layer.

[0116] As described with reference to Figures 5A and 5B, some of the polarized components are not fully rotated as they pass through each liquid crystal cell, and therefore, rather than diffusing the polarized components in different directions before and after rotation within one liquid crystal cell, the corresponding polarized components are diffused in separate liquid crystal cells, thereby improving the light distribution characteristics and achieving a uniformly shaped irradiation profile.

[0117] According to this embodiment, by adopting a configuration in which the liquid crystal cells arranged in four stages diffuse each polarized component before being rotated by the liquid crystal layer and do not diffuse it after the optical rotation, it is possible to obtain a substantially flat intensity distribution within a certain range of polar angles, and an irradiation profile with a regular shape. Also, by adopting a configuration in which the liquid crystal cells arranged in four stages diffuse each polarized component before or after being rotated by the liquid crystal layer and do not diffuse it before or after the optical rotation in one liquid crystal cell, it is possible to obtain a substantially flat intensity distribution within a certain range of polar angles, and an irradiation profile with a regular shape.

[0118] [Second embodiment] This embodiment shows an example in which the liquid crystal light control element is composed of five liquid crystal cells. Each liquid crystal cell has a liquid crystal layer between a pair of substrates, and strip electrodes as shown in Figure 1 are provided on at least one of the substrates.

[0119] 2-1. Third Configuration 13 shows the electrode arrangement in each liquid crystal cell of a liquid crystal light control element 102 according to the third configuration, and the state when light incident on the liquid crystal light control element 102 passes through each liquid crystal cell. The liquid crystal light control element 102 according to the third configuration has first to fifth liquid crystal cells. As described in the first embodiment, each liquid crystal cell is configured such that the first electrode on the first substrate side is composed of a strip electrode, and the second electrode on the second substrate side is composed of a strip electrode.

[0120] As shown in Figure 13, the liquid crystal light control element 102 of the third configuration has a first liquid crystal cell 10, a second liquid crystal cell 20, a third liquid crystal cell 30, a fourth liquid crystal cell 40, and a fifth liquid crystal cell 50 arranged so as to overlap from the light incident side to the light exit side.

[0121] The first liquid crystal cell 10 is arranged so that the first strip electrodes E11A and second strip electrodes E11B on the first substrate S11 side extend in the X-axis direction, and the third strip electrodes E12A and fourth strip electrodes E12B on the second substrate S12 side extend in the Y-axis direction. The second liquid crystal cell 20 and the third liquid crystal cell 30 are arranged so that the first strip electrodes E21A and E31A and second strip electrodes E21B and E31B on the first substrates S21 and S31 side extend in the Y-axis direction, and the third strip electrodes E22A and E32A and fourth strip electrodes E22B and E32B on the second substrates S22 and S32 side extend in the X-axis direction. The fourth liquid crystal cell 40 and the fifth liquid crystal cell 50 are arranged such that the first strip electrodes E41A, E51A and the second strip electrodes E41B, E51B on the first substrate S41, S51 side extend in the X-axis direction, and the third strip electrodes E42A, E52A and the fourth strip electrodes E42B, E52B on the second substrate S42, S52 side extend in the Y-axis direction. Also, similar to the first embodiment, the alignment direction of the alignment film of each liquid crystal cell is arranged in a direction intersecting the extension direction of the strip electrodes. This embodiment can also be considered a configuration in which one more liquid crystal cell is added to the configuration of the modified first embodiment shown in FIGS. 9 and 10 on the incident side. This added liquid crystal cell can also be considered the same liquid crystal cell as the third and fourth liquid crystal cells in the modified first embodiment and is arranged in the same orientation as these liquid crystal cells.

[0122] As in the first embodiment, hatching is used to indicate electrodes to which control signals are applied to form a transverse electric field in Fig. 13. A table is also inserted in Fig. 13, which uses the terms transmission, optical rotation, and diffusion to indicate the state of each polarization component when light containing a first polarization component PL1 and a second polarization component PL2 passes through the first electrode, liquid crystal layer, and second electrode of each liquid crystal cell.

[0123] Table 3 shows the control signals applied to each liquid crystal cell of the liquid crystal light control element 102 according to the third configuration shown in FIG. [Table 3]

[0124] As shown in Table 3, in each liquid crystal cell of the liquid crystal light control element 102 according to the third configuration, rectangular wave control signals A and B are applied to the first electrodes (first strip electrode, second strip electrode) on the first substrate side (light incident side), and a constant voltage control signal E is applied to the second electrodes (third strip electrode, fourth strip electrode) on the second substrate side (light exit side). That is, in the liquid crystal light control element 102 according to the third configuration shown in Fig. 13, the control signals A and B are applied to the first electrodes of each liquid crystal cell, and the control signal E is applied to the second electrode, and a transverse electric field is generated only on the first substrate side.

[0125] Next, we will explain how light incident on the liquid crystal light control element 102 according to the third configuration is diffused, rotated, and transmitted. In the third configuration as well, the first polarization component PL1 is initially s-polarized light (the state immediately before it enters the liquid crystal light control element 102), and the second polarization component PL2 is initially p-polarized light.

[0126] 13, attention is focused on the first polarized component PL1. The first polarized component PL1 is incident on the first liquid crystal cell 10 in an s-polarized state. The first polarized component PL1 (s-polarized) incident on the first liquid crystal cell 10 is not diffused by the first electrode E11, is rotated by 90 degrees in the first liquid crystal layer LC1 to become p-polarized light, is not diffused by the second electrode E12, and is emitted from the first liquid crystal cell 10. The first polarized component PL1 (p-polarized) incident on the second liquid crystal cell 20 is not diffused by the first electrode E21, is rotated by 90 degrees in the second liquid crystal layer LC2 to become s-polarized light, is not diffused by the second electrode E22, and is emitted from the second liquid crystal cell 20. The first polarization component PL1 (s-polarized light) incident on the third liquid crystal cell 30 is diffused in the X-axis direction by the first electrode E31, rotated by 90 degrees by the third liquid crystal layer LC3 to become p-polarized light, and is emitted from the third liquid crystal cell 30 without being diffused by the second electrode E32. The first polarization component PL1 (p-polarized light) incident on the fourth liquid crystal cell 40 is diffused in the Y-axis direction by the first electrode E41, rotated by 90 degrees by the fourth liquid crystal layer LC4 to become s-polarized light, and is emitted from the fourth liquid crystal cell 40 without being diffused by the second electrode E42. The first polarization component PL1 (s-polarized light) incident on the fifth liquid crystal cell 50 is not diffused by the first electrode E51, rotated by 90 degrees by the fifth liquid crystal layer LC5 to become p-polarized light, and is emitted from the fifth liquid crystal cell 50 without being diffused by the second electrode E52. In this way, the first polarization component PL1 (s-polarized light) incident on the liquid crystal light control element 102 of the third configuration is diffused once in the X-axis direction and once in the Y-axis direction, rotated five times in the liquid crystal layer, and emitted in a p-polarized state.

[0127] 13, attention is focused on the second polarized component PL2. The second polarized component PL2 is incident on the first liquid crystal cell 10 in a p-polarized state. The second polarized component PL2 (p-polarized) incident on the first liquid crystal cell 10 is diffused in the Y-axis direction by the first electrode E11, rotated by 90 degrees by the first liquid crystal layer LC1 to become s-polarized light, and exits the first liquid crystal cell 10 without being diffused by the second electrode E12. The second polarized component PL2 (s-polarized) incident on the second liquid crystal cell 20 is diffused in the X-axis direction by the first electrode E21, rotated by 90 degrees by the second liquid crystal layer LC2 to become p-polarized light, and exits the second liquid crystal cell 20 without being diffused by the second electrode E22. The second polarization component PL2 (p-polarized light) incident on the third liquid crystal cell 30 is not diffused by the first electrode E31, is rotated by 90 degrees by the third liquid crystal layer LC3 to become s-polarized light, and is not diffused by the second electrode E32, before being emitted from the third liquid crystal cell 30. The second polarization component PL2 (s-polarized light) incident on the fourth liquid crystal cell 40 is not diffused by the first electrode E41, is rotated by 90 degrees by the fourth liquid crystal layer LC4 to become p-polarized light, and is not diffused by the second electrode E42, before being emitted from the fourth liquid crystal cell 40. The second polarization component PL2 (p-polarized light) incident on the fifth liquid crystal cell 50 is diffused in the Y-axis direction by the first electrode E51, is rotated by 90 degrees by the fifth liquid crystal layer LC5 to become s-polarized light, and is not diffused by the second electrode E52, before being emitted from the fifth liquid crystal cell 50. In this way, the second polarization component PL2 (p-polarized light) incident on the liquid crystal light control element 102 of the third configuration is diffused once in the X-axis direction and twice in the Y-axis direction, rotated five times in the liquid crystal layer, and emitted in an s-polarized state.

[0128] In the third configuration, the first polarized component PL1 is diffused in the X-axis direction before being rotated by the third liquid crystal cell 30, and is diffused in the Y-axis direction before being rotated by the fourth liquid crystal cell 40, and the second polarized component PL2 is diffused in the X-axis direction before being rotated by the second liquid crystal cell 20, and is diffused in the Y-axis direction before being rotated by the third liquid crystal cell 30, and is further diffused in the Y-axis direction before being rotated by the fifth liquid crystal cell 50. In the third configuration, the second electrodes E12, E22, E32, R42, and E52 may be planar (also referred to as flat or solid) electrodes as shown in Fig. 6, or may be configured without second electrodes as shown in Fig. 8.

[0129] 2-2. Fourth Configuration In the fourth configuration, the liquid crystal light control element does not diffuse the polarized components on the first electrode E11, E41, E51 side (light incident side) of the first liquid crystal cell 10, the second liquid crystal cell 20, and the fifth liquid crystal cell 50, but diffuses them on the second electrode E12, E42, E52 side (light exit side), and diffuses them on the first electrode E21, E31 side (light incident side) of the third liquid crystal cell 30 and the fourth liquid crystal cell 40, but does not diffuse them on the second electrode E22, E32 side.

[0130] 14 shows the electrode arrangement in each liquid crystal cell of the liquid crystal light control element 102 according to the fourth configuration, and the state when light incident on the liquid crystal light control element 102 passes through each liquid crystal cell. The arrangement of the strip electrodes in each liquid crystal cell is the same as in the third configuration.

[0131] Table 4 shows the control signals applied to each liquid crystal cell of the liquid crystal light control element 102 according to the fourth configuration shown in FIG. [Table 4]

[0132] As shown in Table 4, in the liquid crystal light control element 102 of the fourth configuration, in the first liquid crystal cell 10, the second liquid crystal cell 20, and the fifth liquid crystal cell 50, a control signal E of a constant voltage is applied to the first electrodes E11, E21, E51 (first strip electrodes E11A, E21A, E51A, second strip electrodes E11B, E21B, E51B) on the light incident side, and control signals A and B are applied to the second electrodes E12, E22, E52 (third strip electrodes E12A, E22A, E52A, fourth strip electrodes E12B, E22B, E52B) on the light exit side after optical rotation. In addition, in the third liquid crystal cell 30 and the fourth liquid crystal cell 40, control signals A and B are applied to the first electrodes E31 and E41 (first strip electrodes E31A and E41A, second strip electrodes E31B and E41B) on the light incident side, and a control signal E of a constant voltage is applied to the second electrodes E32 and E42 (third strip electrodes E32A and E42A, fourth strip electrodes E32B and E42B). That is, the liquid crystal light control element 102 of the fourth configuration shown in Figure 14 does not generate a horizontal electric field on the side of the first substrates S11, S21, and S51 of the first liquid crystal cell 10, the second liquid crystal cell 20, and the fifth liquid crystal cell 50, but generates a horizontal electric field on the side of the second substrates S12, S22, and S52, and in the third liquid crystal cell 30 and the fourth liquid crystal cell 40, generates a horizontal electric field on the side of the first substrates S31 and S41, but does not generate a horizontal electric field on the side of the second substrates S32 and S42.

[0133] Next, we will explain how light incident on the liquid crystal light control element 102 according to the fourth configuration is diffused, rotated, and transmitted. In the fourth configuration as well, the initial state of the first polarization component PL1 (the state immediately before it enters the liquid crystal light control element 102) is s-polarized light, and the initial state of the second polarization component PL2 is p-polarized light.

[0134] 14, attention is focused on the first polarized component PL1. The first polarized component PL1 is incident on the first liquid crystal cell 10 in an s-polarized state. The first polarized component PL1 (s-polarized) incident on the first liquid crystal cell 10 is not diffused by the first electrode E11, is rotated by 90 degrees in the first liquid crystal layer LC1 to become p-polarized, is not diffused by the second electrode E12, and is emitted from the first liquid crystal cell 10. The first polarized component PL1 (p-polarized) incident on the second liquid crystal cell 20 is not diffused by the first electrode E21, is rotated by 90 degrees in the second liquid crystal layer LC2 to become s-polarized, is not diffused by the second electrode E22, and is emitted from the second liquid crystal cell 20. The first polarization component PL1 (s-polarized light) incident on the third liquid crystal cell 30 is diffused in the X-axis direction by the first electrode E31, rotated by 90 degrees by the third liquid crystal layer LC3 to become p-polarized light, and is emitted from the third liquid crystal cell 30 without being diffused by the second electrode E32. The first polarization component PL1 (p-polarized light) incident on the fourth liquid crystal cell 40 is diffused in the Y-axis direction by the first electrode E41, rotated by 90 degrees by the fourth liquid crystal layer LC4 to become s-polarized light, and is emitted from the fourth liquid crystal cell 40 without being diffused by the second electrode E42. The first polarization component PL1 (s-polarized light) incident on the fifth liquid crystal cell 50 is not diffused by the first electrode E51, rotated by 90 degrees by the fifth liquid crystal layer LC5 to become p-polarized light, and is emitted from the fifth liquid crystal cell 50 without being diffused by the second electrode E52. In this way, the first polarization component PL1 (s-polarized light) incident on the liquid crystal light control element 102 of the fourth configuration is diffused once in the X-axis direction and once in the Y-axis direction, rotated five times in the liquid crystal layer, and emitted in a p-polarized state.

[0135] 14, attention is focused on the second polarized component PL2. The second polarized component PL2 is incident on the first liquid crystal cell 10 in a p-polarized state. The second polarized component PL2 (p-polarized) incident on the first liquid crystal cell 10 is not diffused by the first electrode E11, but is rotated by 90 degrees in the first liquid crystal layer LC1 to become s-polarized light, is diffused in the X-axis direction by the second electrode E12, and is emitted from the first liquid crystal cell 10. The second polarized component PL2 (s-polarized) incident on the second liquid crystal cell 20 is not diffused by the first electrode E21, but is rotated by 90 degrees in the second liquid crystal layer LC2 to become p-polarized light, is diffused in the Y-axis direction by the second electrode E22, and is emitted from the second liquid crystal cell 20. The second polarization component PL2 (p-polarized light) incident on the third liquid crystal cell 30 is not diffused by the first electrode E31, is rotated by 90 degrees by the third liquid crystal layer LC3 to become s-polarized light, is not diffused by the second electrode E32, and is emitted from the third liquid crystal cell 30. The second polarization component PL2 (s-polarized light) incident on the fourth liquid crystal cell 40 is not diffused by the first electrode E41, is rotated by 90 degrees by the fourth liquid crystal layer LC4 to become p-polarized light, is not diffused by the second electrode E42, and is emitted from the fourth liquid crystal cell 40. The second polarization component PL2 (p-polarized light) incident on the fifth liquid crystal cell 50 is not diffused by the first electrode E51, is rotated by 90 degrees by the fifth liquid crystal layer LC5 to become s-polarized light, is diffused in the X-axis direction by the second electrode E52, and is emitted from the fifth liquid crystal cell 50. In this way, the second polarization component PL2 (p-polarized light) incident on the liquid crystal light control element 102 of the fourth configuration is diffused twice in the X-axis direction and once in the Y-axis direction, rotated five times in the liquid crystal layer, and emitted in an s-polarized state.

[0136] In the fourth configuration, the first polarization component PL1 is diffused in the X-axis direction before being rotated by the third liquid crystal cell 30, and is diffused in the Y-axis direction before being rotated by the fourth liquid crystal cell 40, and the second polarization component PL2 is diffused in the X-axis direction after being rotated by the first liquid crystal cell 10, and is diffused in the Y-axis direction after being rotated by the second liquid crystal cell 20, and is diffused in the X-axis direction after being rotated by the fifth liquid crystal cell 50.

[0137] 2-3. Reference example 2 15 shows a liquid crystal light control element according to Reference Example 2. In Reference Example 2, a control signal A is applied to the first strip electrode E11A on the first substrate S11 side of the first liquid crystal cell 10, a control signal B is applied to the second strip electrode E11B, a control signal A is applied to the third strip electrode E12A on the second substrate S12 side, and a control signal B is applied to the fourth strip electrode E12B. The same applies to the second liquid crystal cell 20, the third liquid crystal cell 30, the fourth liquid crystal cell 40, and the fifth liquid crystal cell 50. That is, a lateral electric field is generated on both substrate sides in all of the first to fifth liquid crystal cells.

[0138] 15, focusing on the first polarization component PL1, the first polarization component PL1 enters the first liquid crystal cell 10 as s-polarized light. The first polarization component PL1 is not diffused by the first liquid crystal cell 10 and is rotated by 90 degrees by the first liquid crystal layer LC1 to become p-polarized light. The first polarization component PL1 is not diffused by the second liquid crystal cell 20 and is rotated by 90 degrees by the second liquid crystal layer LC2 to become s-polarized light again. The first polarization component PL1 enters the third liquid crystal cell 30 as s-polarized light, is diffused in the X-axis direction by the first electrode E31, is rotated by 90 degrees by the third liquid crystal layer LC3 to become p-polarized light, and is diffused in the Y-axis direction by the second electrode E32. The first polarization component PL1 enters the fourth liquid crystal cell 40 as p-polarized light, is diffused in the Y-axis direction by the first electrode E41, is rotated by 90 degrees by the fourth liquid crystal layer LC4 to become s-polarized light, and is diffused in the X-axis direction by the second electrode E42. The first polarized component PL1 is not diffused by the fifth liquid crystal cell 50, but is optically rotated by 90 degrees by the fifth liquid crystal layer LC5 and is emitted in a p-polarized state.

[0139] 15, focusing on the second polarization component PL2, the second polarization component PL2 enters the first liquid crystal cell 10 in a p-polarized state. The second polarization component PL2 is diffused in the Y-axis direction by the first electrode E11, rotated 90 degrees by the first liquid crystal layer LC1 to become s-polarized, and diffused in the X-axis direction by the second electrode E12. The second polarization component PL2 enters the second liquid crystal cell 20 in an s-polarized state, diffused in the X-axis direction by the first electrode E21, rotated 90 degrees by the second liquid crystal layer LC2 to become p-polarized, and diffused in the Y-axis direction by the second electrode E22. The second polarization component PL2 is not diffused by the third liquid crystal cell 30, but is rotated 90 degrees by the third liquid crystal layer LC3 to become s-polarized. The second polarization component PL2 is not diffused by the fourth liquid crystal cell, but is diffused 90 degrees by the fourth liquid crystal layer LC4 to become p-polarized. The second polarized component PL2 enters the fifth liquid crystal cell 50 in a p-polarized state, is diffused in the Y-axis direction by the first electrode E51, is rotated 90 degrees by the fifth liquid crystal layer LC5 to become an s-polarized state, is diffused in the X-axis direction by the second electrode E52, and exits in an s-polarized state.

[0140] Thus, in the liquid crystal light control element of Reference Example 2, the first polarization component PL1 is diffused in the X-axis and Y-axis directions by the third liquid crystal cell 30 and the fourth liquid crystal cell 40, and the second polarization component PL2 is diffused in the X-axis and Y-axis directions by the first liquid crystal cell 10, the second liquid crystal cell 20, and the fifth liquid crystal cell 50.

[0141] 2-4.Angular characteristics Fig. 16 shows a graph of the luminance-angle characteristics of the liquid crystal light control element 102 according to the third and fourth configurations. Fig. 16 also shows the characteristics of Reference Example 2 in the same graph. In the graph shown in Fig. 16, as in Fig. 12A, the horizontal axis indicates the polar angle, and the vertical axis indicates the luminance normalized with the luminance at the center (polar angle 0 degrees) set to 100%.

[0142] 16, the characteristics of the third configuration of liquid crystal light control element 102 show that, although the luminance in the ranges of polar angles from approximately +10 degrees to +45 degrees and from approximately -10 degrees to -45 degrees drops by about 5% from the center luminance, a constant luminance distribution is obtained within the same range. The third configuration shows that a substantially flat intensity distribution can be obtained within a certain range of polar angles by adopting a configuration in which each polarization component is diffused before being rotated by the liquid crystal layer and not diffused after being rotated. Furthermore, it can be seen that the range of polar angles over which the luminance distribution is constant is wider than in the first configuration.

[0143] It can be seen that the characteristics of the liquid crystal light control element 102 according to the fourth configuration show that although the luminance in the polar angle ranges of approximately +20 to +45 degrees and -20 to -45 degrees drops by approximately 45% from the center luminance, a constant luminance distribution is obtained within the same ranges. In the fourth configuration, the first polarized component PL1 is diffused before the optical rotation in the liquid crystal layer, and the second polarized component PL2 is diffused after the optical rotation. Although the characteristics of the fourth configuration show a drop in luminance in the polar angle ranges of approximately +20 to +45 degrees and -20 to -45 degrees, a profile similar to that of the fourth configuration is obtained.

[0144] Thus, when comparing the third and fourth configurations, in the third configuration, both the first and second polarization components are pre-diffused once in the X-axis direction as they pass through the liquid crystal light control element 102, whereas in the fourth configuration, the first polarization component is pre-diffused once in the X-axis direction and the second polarization component is post-diffused twice in the X-axis direction, indicating that two pre-diffusions suppress brightness reduction and maintain a constant brightness over a wider polar angle range than one pre-diffusion and two post-diffusions.

[0145] When comparing the third configuration with the first configuration, the brightness is relatively higher and the range of polar angles over which the brightness remains constant is wider. A similar trend is observed when comparing the fourth configuration with the second configuration. One possible reason for this change in characteristics is that the second polarization component PL2 is diffused one more time than in the first configuration.

[0146] The characteristics of the liquid crystal light control element shown in Reference Example 2 show that the luminance intensity distribution is greatest at a polar angle of 0 degrees and tends to decrease linearly as the polar angle increases in the positive and negative directions (i.e., left and right directions). As in Reference Example 1, the liquid crystal light control element of Reference Example 2 diffuses each polarized component in front of and behind the liquid crystal layer, thereby obtaining a luminance distribution that decreases linearly in the polar angle direction.

[0147] More specifically, in Reference Example 2, the first polarized component is pre-diffused once in the X-axis direction, but is post-diffused in the Y-axis direction within the same liquid crystal cell (third liquid crystal cell) immediately after the pre-diffusion. The second polarized component is pre-diffused once in the X-axis direction, but is post-diffused in the Y-axis direction within the same liquid crystal cell (second liquid crystal cell) immediately before the post-diffusion. Furthermore, in Reference Example 2, the first polarized component is pre-diffused once in the Y-axis direction, but is post-diffused in the X-axis direction within the same liquid crystal cell (fourth liquid crystal cell) immediately after the pre-diffusion. The second polarized component is pre-diffused once in the Y-axis direction within the first and fifth liquid crystal cells, and is post-diffused once in the X-axis direction within the same liquid crystal cell immediately after the pre-diffusion. In other words, in Reference Example 2, the first polarized component is pre-diffused once in the X-axis direction and post-diffused once, but both are accompanied by diffusion in the Y-axis direction within the same liquid crystal cell. In Reference Example 2, the second polarization component is pre-diffused once in the X-axis direction and post-diffused twice, but both are accompanied by diffusion in the Y-axis direction within the same liquid crystal cell. Figure 16 shows that when diffusion occurs before and after optical rotation within the same liquid crystal cell, the luminance decreases monotonically as the polar angle increases, even if the number of pre-diffusions is the same, compared to when diffusion is performed only by pre-diffusion (third configuration).

[0148] According to FIG. 16, in the third configuration, the half-value width is the same as that of Reference Example 2, but the brightness within the half-value width is improved compared to Reference Example 2 while being kept constant, and in the fourth configuration, the half-value width is the same as that of Reference Example 2, but the brightness within the half-value width is reduced compared to Reference Example 2 while being kept constant.

[0149] According to this embodiment, a substantially flat intensity distribution can be obtained within a certain range of polar angles by using a configuration in which the liquid crystal cells arranged in five stages diffuse each polarized component before being rotated by the liquid crystal layer and do not diffuse it after the optical rotation. Also, a substantially flat intensity distribution can be obtained within a certain range of polar angles by using a configuration in which the liquid crystal cells arranged in five stages diffuse each polarized component before or after being rotated by the liquid crystal layer and do not diffuse it within one liquid crystal cell before or after the optical rotation.

[0150] [Third embodiment] 3-1. Fifth Configuration 17 shows the electrode arrangement in each liquid crystal cell of a liquid crystal light control element 102 according to the fifth configuration, and the state when light incident on the liquid crystal light control element 102 passes through each liquid crystal cell. The liquid crystal light control element 102 according to the fifth configuration has first to sixth liquid crystal cells. As explained in the first embodiment, each liquid crystal cell is configured such that the first electrode on the first substrate side is composed of a strip electrode, and the second electrode on the second substrate side is composed of a strip electrode.

[0151] As shown in Figure 17, the liquid crystal light control element 102 of the fifth configuration has a first liquid crystal cell 10, a second liquid crystal cell 20, a third liquid crystal cell 30, a fourth liquid crystal cell 40, a fifth liquid crystal cell 50, and a sixth liquid crystal cell 60 arranged so as to overlap from the light incident side to the light exit side.

[0152] The first liquid crystal cell 10 and the second liquid crystal cell 20 are arranged such that the first strip electrodes E11A, E21A and the second strip electrodes E11B, E21B on the first substrates S11, S21 side extend in the X-axis direction, and the third strip electrodes E12A, E22A and the fourth strip electrodes E12B, E22B on the second substrates S12, S22 side extend in the Y-axis direction. The third liquid crystal cell 30 and the fourth liquid crystal cell 40 are arranged such that the first strip electrodes E31A, E41A and the second strip electrodes E31B, E41B on the first substrates S31, S41 side extend in the Y-axis direction, and the third strip electrodes E32A, E42A and the fourth strip electrodes E32B, E42B on the second substrates S32, S42 side extend in the X-axis direction. The fifth liquid crystal cell 50 and the sixth liquid crystal cell 60 are arranged such that the first strip electrodes E51A, E61A and the second strip electrodes E51B, E61B on the first substrates S51, S61 side extend in the X-axis direction, and the third strip electrodes E52A, E62A and the fourth strip electrodes E52B, E62B on the second substrates S52, S62 side extend in the Y-axis direction. Also, similar to the first embodiment, the alignment direction of the alignment film of each liquid crystal cell is arranged in a direction that intersects with the extension direction of the strip electrodes.

[0153] As described above, in the liquid crystal light control element 102 according to the fifth configuration, the first and second liquid crystal cells 10 and 20 have the same arrangement of strip electrodes as the fifth and sixth liquid crystal cells 50 and 60, and the third and fourth liquid crystal cells 30 and 40 have their strip electrodes rotated by 90 degrees relative to these liquid crystal cells. This embodiment can also be said to have a configuration in which two liquid crystal cells are added to the configuration of the modified first embodiment shown in Figures 9 and 10 and stacked on the incident side. The added liquid crystal cells can also be said to be the same liquid crystal cells as the third and fourth liquid crystal cells in the modified first embodiment and are arranged in the same orientation as these liquid crystal cells.

[0154] As in the first embodiment, hatching is used to indicate electrodes to which control signals are applied to form a transverse electric field in Fig. 17. A table is also inserted in Fig. 17, which uses the terms transmission, optical rotation, and diffusion to indicate the state of each polarization component when light including a first polarization component PL1 and a second polarization component PL2 passes through the first electrode, liquid crystal layer, and second electrode of each liquid crystal cell.

[0155] Table 5 shows the control signals applied to each liquid crystal cell of the liquid crystal light control element 102 according to the fifth configuration shown in FIG. [Table 5]

[0156] As shown in Table 5, in each liquid crystal cell of the liquid crystal light control element 102 according to the fifth configuration, rectangular wave control signals A and B are applied to the first electrodes (first strip electrode, second strip electrode) on the first substrate side (light incident side), and a constant voltage control signal E is applied to the second electrodes (third strip electrode, fourth strip electrode) on the second substrate side (light exit side). That is, in the liquid crystal light control element 102 according to the fifth configuration shown in Fig. 17, the control signals A and B are applied to the first electrodes of each liquid crystal cell, and the control signal E is applied to the second electrode, and a transverse electric field is generated only on the first substrate side.

[0157] Next, we will explain how light incident on the liquid crystal light control element 102 according to the fifth configuration is diffused, rotated, and transmitted. In the fifth configuration as well, the first polarization component PL1 is initially s-polarized light (the state immediately before it enters the liquid crystal light control element 102), and the second polarization component PL2 is initially p-polarized light.

[0158] 17, attention is focused on the first polarized component PL1. The first polarized component PL1 is incident on the first liquid crystal cell 10 in an s-polarized state. The first polarized component PL1 (s-polarized) incident on the first liquid crystal cell 10 is not diffused by the first electrode E11, is rotated by 90 degrees in the first liquid crystal layer LC1 to become p-polarized, and is then emitted from the first liquid crystal cell 10 without being diffused by the second electrode E12. The first polarized component PL1 (p-polarized) incident on the second liquid crystal cell 20 is diffused in the Y-axis direction by the first electrode E21, is rotated by 90 degrees in the second liquid crystal layer LC2 to become s-polarized, and is then emitted from the second liquid crystal cell 20 without being diffused by the second electrode E22. The first polarization component PL1 (s-polarized light) incident on the third liquid crystal cell 30 is diffused in the X-axis direction by the first electrode E31, rotated by 90 degrees by the third liquid crystal layer LC3 to become p-polarized light, and is not diffused by the second electrode E32 before being emitted from the third liquid crystal cell 30. The first polarization component PL1 (p-polarized light) incident on the fourth liquid crystal cell 40 is not diffused by the first electrode E41, rotated by 90 degrees by the fourth liquid crystal layer LC4 to become s-polarized light, and is not diffused by the second electrode E42 before being emitted from the fourth liquid crystal cell 40. The first polarization component PL1 (s-polarized light) incident on the fifth liquid crystal cell 50 is not diffused by the first electrode E51, rotated by 90 degrees by the fifth liquid crystal layer LC5 to become p-polarized light, and is not diffused by the second electrode E52 before being emitted from the fifth liquid crystal cell 50. The first polarization component PL1 (p-polarized light) incident on the sixth liquid crystal cell 60 is diffused in the Y-axis direction by the first electrode E61, rotated by 90 degrees by the sixth liquid crystal layer LC6 to become s-polarized light, and is not diffused by the second electrode E62, before being emitted from the sixth liquid crystal cell 60. In this way, the first polarization component PL1 (s-polarized light) incident on the liquid crystal light control element 102 according to the fifth configuration is diffused once in the X-axis direction and twice in the Y-axis direction, rotated six times by the liquid crystal layer, and emitted in an s-polarized state.

[0159] 17, attention is focused on the second polarized component PL2. The second polarized component PL2 is incident on the first liquid crystal cell 10 in a p-polarized state. The second polarized component PL2 (p-polarized) incident on the first liquid crystal cell 10 is diffused in the Y-axis direction by the first electrode E11, rotated by 90 degrees by the first liquid crystal layer LC1 to become s-polarized light, and is emitted from the first liquid crystal cell 10 without being diffused by the second electrode E12. The second polarized component PL2 (s-polarized) incident on the second liquid crystal cell 20 is not diffused by the first electrode E21, rotated by 90 degrees by the second liquid crystal layer LC2 to become p-polarized light, and is emitted from the second liquid crystal cell 20 without being diffused by the second electrode E22. The second polarization component PL2 (p-polarized light) incident on the third liquid crystal cell 30 is not diffused by the first electrode E31, is rotated by 90 degrees by the third liquid crystal layer LC3 to become s-polarized light, and is emitted from the third liquid crystal cell 30 without being diffused by the second electrode E32. The second polarization component PL2 (s-polarized light) incident on the fourth liquid crystal cell 40 is diffused in the X-axis direction by the first electrode E41, is rotated by 90 degrees by the fourth liquid crystal layer LC4 to become p-polarized light, and is emitted from the fourth liquid crystal cell 40 without being diffused by the second electrode E42. The second polarization component PL2 (p-polarized light) incident on the fifth liquid crystal cell 50 is diffused in the Y-axis direction by the first electrode E51, is rotated by 90 degrees by the fifth liquid crystal layer LC5 to become s-polarized light, and is emitted from the fifth liquid crystal cell 50 without being diffused by the second electrode E52. The second polarization component PL2 (s-polarized light) incident on the sixth liquid crystal cell 60 is not diffused by the first electrode E61, is rotated by 90 degrees in the sixth liquid crystal layer LC6 to become p-polarized light, is not diffused by the second electrode E62, and is emitted from the sixth liquid crystal cell 60. In this way, the second polarization component PL2 (p-polarized light) incident on the liquid crystal light control element 102 according to the fifth configuration is diffused once in the X-axis direction and twice in the Y-axis direction, is rotated six times in the liquid crystal layer, and is emitted in an s-polarized state.

[0160] In the fifth configuration, the first polarized component PL1 is diffused in the Y-axis direction before being rotated by the second liquid crystal cell 20 and the sixth liquid crystal cell 60, and is diffused in the X-axis direction before being rotated by the third liquid crystal cell 30. The second polarized component PL2 is diffused in the Y-axis direction before being rotated by the first liquid crystal cell 10 and the fifth liquid crystal cell 50, and is diffused in the X-axis direction before being rotated by the third liquid crystal cell 30. In the fifth configuration, the second electrodes E12, E22, E32, R42, E52, and E62 may be planar (also referred to as flat or solid) electrodes as shown in Fig. 6, or may be configured without second electrodes as shown in Fig. 8.

[0161] 3-2. Sixth Configuration In the sixth configuration, the liquid crystal light control element diffuses the polarized components on the first electrode E11, E41, E51 side (light incident side) of the first liquid crystal cell 10, the fourth liquid crystal cell 40, and the fifth liquid crystal cell 50, but does not diffuse them on the second electrode E12, E42, E52 side (light exit side), and does not diffuse them on the first electrode E21, E31, E61 side (light incident side) of the second liquid crystal cell 20, the third liquid crystal cell 30, and the sixth liquid crystal cell 60, but diffuses them on the second electrode E22, E32, E62 side (light exit side).

[0162] 18 shows the electrode arrangement in each liquid crystal cell of the liquid crystal light control element 102 according to the sixth configuration, and the state when light incident on the liquid crystal light control element 102 passes through each liquid crystal cell. The arrangement of the strip electrodes in each liquid crystal cell is the same as in the fifth configuration.

[0163] Table 6 shows the control signals applied to each liquid crystal cell of the liquid crystal light control element 102 according to the sixth configuration shown in FIG. [Table 6]

[0164] As shown in Table 6, in the liquid crystal light control element 102 of the sixth configuration, in the first liquid crystal cell 10, the fourth liquid crystal cell 40, and the fifth liquid crystal cell 50, control signals A and B are applied to the first electrodes E11, E41, E51 (first strip electrodes E11A, E41A, E51A, second strip electrodes E11B, E41B, E51B) on the light incident side, and control signal E is applied to the second electrodes E12, E42, E52 (third strip electrodes E12A, E42A, E52A, fourth strip electrodes E12B, E42B, E52B) on the light exit side after optical rotation. In addition, in the second liquid crystal cell 20, the third liquid crystal cell 30, and the sixth liquid crystal cell 60, a control signal E is applied to the first electrodes E21, E31, and E61 (first strip electrodes E21A, E31A, E61A, second strip electrodes E21B, E31B, E61B) on the light incident side, and control signals A and B are applied to the second electrodes E22, E32, and E42 (third strip electrodes E22A, E32A, E42A, fourth strip electrodes E22B, E32B, E42B). That is, the liquid crystal light control element 102 of the sixth configuration shown in Figure 18 generates a horizontal electric field on the first substrates S11, S41, and S51 sides of the first liquid crystal cell 10, the fourth liquid crystal cell 40, and the fifth liquid crystal cell 50, but does not generate a horizontal electric field on the second substrates S12, S42, and S52 sides, and does not generate a horizontal electric field on the first substrates S21, S31, and S61 sides of the second liquid crystal cell 20, the third liquid crystal cell 30, and the sixth liquid crystal cell 60, but generates a horizontal electric field on the second substrates S22, S32, and S62 sides.

[0165] Next, we will explain how light incident on the liquid crystal light control element 102 according to the sixth configuration is diffused, rotated, and transmitted. In the sixth configuration as well, the first polarization component PL1 is initially s-polarized light (the state immediately before it enters the liquid crystal light control element 102), and the second polarization component PL2 is initially p-polarized light.

[0166] 18, attention is focused on the first polarized component PL1. The first polarized component PL1 is incident on the first liquid crystal cell 10 in an s-polarized state. The first polarized component PL1 (s-polarized) incident on the first liquid crystal cell 10 is not diffused by the first electrode E11, is rotated by 90 degrees by the first liquid crystal layer LC1 to become p-polarized light, is not diffused by the second electrode E12, and is emitted from the first liquid crystal cell 10. The first polarized component PL1 (p-polarized) incident on the second liquid crystal cell 20 is not diffused by the first electrode E21, is rotated by 90 degrees by the second liquid crystal layer LC2 to become s-polarized light, is diffused in the X-axis direction by the second electrode E22, and is emitted from the second liquid crystal cell 20. The first polarization component PL1 (s-polarized light) incident on the third liquid crystal cell 30 is not diffused by the first electrode E31, but is rotated by 90 degrees by the third liquid crystal layer LC3 to become p-polarized light, is diffused in the Y-axis direction by the second electrode E32, and is emitted from the third liquid crystal cell 30. The first polarization component PL1 (p-polarized light) incident on the fourth liquid crystal cell 40 is not diffused by the first electrode E41, but is rotated by 90 degrees by the fourth liquid crystal layer LC4 to become s-polarized light, is not diffused by the second electrode E42, and is emitted from the fourth liquid crystal cell 40. The first polarization component PL1 (s-polarized light) incident on the fifth liquid crystal cell 50 is not diffused by the first electrode E51, but is rotated by 90 degrees by the fifth liquid crystal layer LC5 to become p-polarized light, is not diffused by the second electrode E52, and is emitted from the fifth liquid crystal cell 50. The first polarization component PL1 (p-polarized light) incident on the sixth liquid crystal cell 60 is not diffused by the first electrode E61, but is rotated by 90 degrees in the sixth liquid crystal layer LC6 to become s-polarized light, is diffused in the X-axis direction by the second electrode E62, and is emitted from the sixth liquid crystal cell 60. In this way, the first polarization component PL1 (s-polarized light) incident on the liquid crystal light control element 102 according to the sixth configuration is diffused twice in the X-axis direction and once in the Y-axis direction after rotation, is rotated six times in the liquid crystal layer, and is emitted in an s-polarized state.

[0167] 18, attention is focused on the second polarized component PL2. The second polarized component PL2 is incident on the first liquid crystal cell 10 in a p-polarized state. The second polarized component PL2 (p-polarized) incident on the first liquid crystal cell 10 is diffused in the Y-axis direction by the first electrode E11, rotated by 90 degrees by the first liquid crystal layer LC1 to become s-polarized light, and is emitted from the first liquid crystal cell 10 without being diffused by the second electrode E12. The second polarized component PL2 (s-polarized) incident on the second liquid crystal cell 20 is not diffused by the first electrode E21, rotated by 90 degrees by the second liquid crystal layer LC2 to become p-polarized light, and is emitted from the second liquid crystal cell 20 without being diffused by the second electrode E22. The second polarization component PL2 (p-polarized light) incident on the third liquid crystal cell 30 is not diffused by the first electrode E31, is rotated by 90 degrees by the third liquid crystal layer LC3 to become s-polarized light, and is emitted from the third liquid crystal cell 30 without being diffused by the second electrode E32. The second polarization component PL2 (s-polarized light) incident on the fourth liquid crystal cell 40 is diffused in the X-axis direction by the first electrode E41, is rotated by 90 degrees by the fourth liquid crystal layer LC4 to become p-polarized light, and is emitted from the fourth liquid crystal cell 40 without being diffused by the second electrode E42. The second polarization component PL2 (p-polarized light) incident on the fifth liquid crystal cell 50 is diffused in the Y-axis direction by the first electrode E51, is rotated by 90 degrees by the fifth liquid crystal layer LC5 to become s-polarized light, and is emitted from the fifth liquid crystal cell 50 without being diffused by the second electrode E52. The second polarization component PL2 (s-polarized light) incident on the sixth liquid crystal cell 60 is not diffused by the first electrode E61, is rotated by 90 degrees in the second liquid crystal layer LC2 to become p-polarized light, is not diffused by the second electrode E62, and is emitted from the sixth liquid crystal cell 60. In this way, the second polarization component PL2 (p-polarized light) incident on the liquid crystal light control element 102 according to the sixth configuration is diffused once in the X-axis direction and twice in the Y-axis direction before being rotated, is rotated five times in the liquid crystal layer, and is emitted in a p-polarized state.

[0168] In the sixth configuration, the first polarization component PL1 is diffused in the X-axis direction after being rotated by the second liquid crystal cell 20 and the fifth liquid crystal cell 50, and is diffused in the Y-axis direction after being rotated by the third liquid crystal cell 30, and the second polarization component PL2 is diffused in the Y-axis direction before being rotated by the first liquid crystal cell 10 and the fifth liquid crystal cell 50, and is diffused in the X-axis direction before being rotated by the third liquid crystal cell 30.

[0169] 3-3. Reference example 3 19 shows a liquid crystal light control element according to Reference Example 3. In Reference Example 3, a control signal A is applied to the first strip electrode E11A on the first substrate S11 side of the first liquid crystal cell 10, a control signal B is applied to the second strip electrode E11B, a control signal A is applied to the third strip electrode E12A on the second substrate S12 side, and a control signal B is applied to the fourth strip electrode E12B. The same applies to the second liquid crystal cell 20, the third liquid crystal cell 30, the fourth liquid crystal cell 40, the fifth liquid crystal cell 50, and the sixth liquid crystal cell 60.

[0170] 19, focusing on the first polarization component PL1, the first polarization component PL1 enters the first liquid crystal cell 10 in an s-polarized state. The first polarization component PL1 is not diffused by the first liquid crystal cell 10, but is rotated by 90 degrees by the first liquid crystal layer LC1 to become p-polarized. The first polarization component PL1 enters the second liquid crystal cell 20 in a p-polarized state, is diffused in the Y-axis direction by the first electrode E21, is rotated by 90 degrees by the second liquid crystal layer LC2 to become s-polarized, and is diffused in the X-axis direction by the second electrode E22. The first polarization component PL1 enters the third liquid crystal cell 30 in an s-polarized state, is diffused in the X-axis direction by the first electrode E31, is rotated by 90 degrees by the third liquid crystal layer LC3 to become p-polarized, and is diffused in the Y-axis direction by the second electrode E32. The first polarized component PL1 enters the fourth liquid crystal cell 40 in a p-polarized state, is not diffused, and is rotated by 90 degrees by the fourth liquid crystal layer LC4 to become s-polarized and is then emitted. The first polarized component PL1 enters the fifth liquid crystal cell 50 in an s-polarized state, is not diffused, and is rotated by 90 degrees by the fifth liquid crystal layer LC5 to become p-polarized and is then emitted. The first polarized component PL1 enters the sixth liquid crystal cell 60 in a p-polarized state, is diffused in the Y-axis direction by the first electrode E61, is rotated by 90 degrees by the sixth liquid crystal layer LC6 to become s-polarized, and is diffused in the X-axis direction by the second electrode E62.

[0171] 19, focusing on the second polarization component PL2, the second polarization component PL2 enters the first liquid crystal cell 10 in a p-polarized state. The second polarization component PL2 is diffused in the Y-axis direction by the first electrode E11, rotated by 90 degrees by the first liquid crystal layer LC1 to become s-polarized, and diffused in the X-axis direction by the second electrode E12. The second polarization component PL2 enters the second liquid crystal cell 20 in an s-polarized state, is not diffused, is rotated by 90 degrees by the second liquid crystal layer LC2 to become p-polarized, and is emitted. The second polarization component PL2 enters the third liquid crystal cell 30 in a p-polarized state, is not diffused, and is rotated by 90 degrees by the third liquid crystal layer LC3 to become s-polarized, and is emitted. The second polarized component PL2 enters the fourth liquid crystal cell 40 in an s-polarized state, is diffused in the X-axis direction by the first electrode E41, is rotated by 90 degrees by the fourth liquid crystal layer LC4 to become p-polarized, and is diffused in the Y-axis direction by the second electrode E42. The second polarized component PL2 enters the fifth liquid crystal cell 50 in a p-polarized state, is diffused in the Y-axis direction by the first electrode E51, is rotated by 90 degrees by the fifth liquid crystal layer LC5 to become s-polarized, and is diffused in the X-axis direction by the second electrode E52. The second polarized component PL2 enters the sixth liquid crystal cell 60 in an s-polarized state, is not diffused, is rotated by 90 degrees by the sixth liquid crystal layer LC6 to become p-polarized, and is emitted.

[0172] Thus, in the liquid crystal light control element of reference example 3, the first polarization component PL1 is diffused in the X-axis direction and the Y-axis direction by the second liquid crystal cell 20, the third liquid crystal cell 30, and the sixth liquid crystal cell 60, respectively, and the second polarization component PL2 is diffused in the X-axis direction and the Y-axis direction by the first liquid crystal cell 10, the fourth liquid crystal cell 40, and the fifth liquid crystal cell 50, respectively.

[0173] 3-4.Angular characteristics Fig. 20 shows a graph of the luminance-angle characteristics of the liquid crystal light control elements 102 according to the fifth and sixth configurations. Fig. 20 also shows the characteristics of Reference Example 3 in the same graph. As with Fig. 12A, the horizontal axis of the graph shown in Fig. 20 indicates polar angle, and the vertical axis indicates luminance normalized with the luminance at the center (polar angle 0 degrees) set to 100%.

[0174] In the graph shown in Figure 20, the characteristics of the fifth configuration of liquid crystal light control element 102 show that the same brightness (100%) as the center brightness (polar angle 0 degrees) is obtained within the polar angle range of ±30 degrees, and although the brightness drops by about 5% within the polar angle range of ±30 to ±45 degrees, a constant brightness distribution is obtained within the same range.The fifth configuration shows that by adopting a configuration in which each polarization component is diffused before being rotated by the liquid crystal layer and not diffused after rotation, a substantially flat intensity distribution can be obtained within a certain range of polar angles.Furthermore, compared to the first and third configurations, it can be seen that the range of polar angles in which the brightness is high and the brightness distribution is constant is wider.

[0175] The characteristics of the sixth configuration of the liquid crystal light control element 102 show a tendency for luminance to decrease as the polar angle increases in the positive and negative directions from the center (polar angle 0 degrees). The rate at which luminance decreases tends to decrease within the polar angle ranges of +30 to +45 degrees and -30 to -45 degrees. In the sixth configuration, the first polarized component PL1 is diffused after optical rotation in the liquid crystal layer, and the second polarized component PL2 is diffused before optical rotation. The characteristics of the sixth configuration show a decrease in luminance overall compared to the fifth configuration, and a different profile is obtained in the angular luminance characteristics.

[0176] Thus, when comparing the fifth and sixth configurations, in the fifth configuration, both the first and second polarization components are pre-diffused once in the X-axis direction as they pass through the liquid crystal light control element 102, whereas in the sixth configuration, the first polarization component is post-diffused twice in the X-axis direction and the second polarization component is pre-diffused once in the X-axis direction, indicating that two pre-diffusions suppress brightness reduction and maintain a constant brightness over a wider polar angle range than one pre-diffusion and two post-diffusions.

[0177] When the fifth configuration is compared with the first and second configurations, the brightness is relatively higher and the range of polar angles at which the brightness remains constant is wider. A similar trend is also seen when the sixth configuration is compared with the second and fourth configurations. One possible cause of this change in characteristics is that the first polarization component PL1 and the second polarization component PL2 are diffused more frequently than in the first and second configurations.

[0178] The characteristics of the liquid crystal light control element shown as Reference Example 3 show that the luminance intensity distribution is greatest at a polar angle of 0 degrees and tends to decrease linearly as the polar angle increases in the positive and negative directions (i.e., left and right directions). As in Reference Examples 1 and 2, the liquid crystal light control element of Reference Example 3 diffuses each polarized component in front of and behind the liquid crystal layer, thereby achieving a luminance distribution that decreases linearly in the polar angle direction.

[0179] More specifically, in Reference Example 3, the first polarized component is pre-diffused once in the X-axis direction, but is post-diffused in the Y-axis direction within the same liquid crystal cell (third liquid crystal cell) immediately after the pre-diffusion. The second polarized component is pre-diffused once in the X-axis direction, but is post-diffused in the Y-axis direction within the same liquid crystal cell (fourth liquid crystal cell) immediately before the post-diffusion. Furthermore, in Reference Example 3, the first polarized component is pre-diffused once in the Y-axis direction within the second and sixth liquid crystal cells, but is post-diffused in the X-axis direction within the same liquid crystal cell immediately after the pre-diffusion. The second polarized component is pre-diffused once in the Y-axis direction within the first and fifth liquid crystal cells, and is post-diffused once in the X-axis direction within the same liquid crystal cell immediately after the pre-diffusion. That is, in Reference Example 3, the first polarized component is pre-diffused once in the X-axis direction and post-diffused twice, both of which involve diffusion in the Y-axis direction within the same liquid crystal cell. In addition, in Reference Example 2, the second polarization component is pre-diffused once in the X-axis direction and post-diffused twice, but both are accompanied by diffusion in the Y-axis direction within the same liquid crystal cell. Figure 20 shows that when diffusion occurs before and after optical rotation within the same liquid crystal cell, even if the number of pre-diffusions is the same, the luminance decreases monotonically as the polar angle increases compared to when diffusion is performed only by pre-diffusion (fifth configuration).

[0180] According to FIG. 20, in the fifth configuration, the half-value width is the same as that of Reference Example 3, but the brightness within the half-value width is improved compared to Reference Example 3 while being kept constant, and in the sixth configuration, the half-value width is the same as that of Reference Example 3, but the brightness within the half-value width is reduced compared to Reference Example 3 while being kept constant.

[0181] According to this embodiment, a substantially flat intensity distribution can be obtained within a certain range of polar angles by using a configuration in which, in six tiered liquid crystal cells, each polarized component is diffused before being rotated by the liquid crystal layer and not diffused after being rotated. Also, a substantially flat intensity distribution can be obtained within a certain range of polar angles by using a configuration in which, in six tiered liquid crystal cells, each polarized component is diffused before or after being rotated by the liquid crystal layer and not diffused within one liquid crystal cell before or after being rotated.

[0182] [Fourth embodiment] FIG. 21 shows a perspective view of an illumination device 100 according to one embodiment of the present invention. The illumination device 100 includes a liquid crystal light control element 102 and a circuit board 104. The liquid crystal light control element 102 has the configurations shown in the first to fourth embodiments. FIG. 21 shows an example in which the liquid crystal light control element 102 is composed of a first liquid crystal cell 10, a second liquid crystal cell 20, a third liquid crystal cell 30, and a fourth liquid crystal cell 40. Between the first liquid crystal cell 10 and the second liquid crystal cell 20, and between the second liquid crystal cell 20 and the third liquid crystal cell A transparent adhesive layer (not shown) is provided between the first liquid crystal cell 30 and the second liquid crystal cell 40, and between the third liquid crystal cell 30 and the fourth liquid crystal cell 40. The liquid crystal light control element 102 has a structure in which adjacent liquid crystal cells arranged in the front and rear are adhered to each other with a transparent adhesive layer.

[0183] The circuit board 104 includes a circuit for driving the liquid crystal light control element 102. The first liquid crystal cell 10 is connected to the circuit board 104 by a first flexible wiring board F1, the second liquid crystal cell 20 is connected to the circuit board 104 by a second flexible wiring board F2, the third liquid crystal cell 30 is connected to the circuit board 104 by a third flexible wiring board F3, and the fourth liquid crystal cell 40 is connected to the circuit board 104 by a fourth flexible wiring board F4. The circuit board 104 outputs control signals to each liquid crystal cell via the flexible wiring boards to control the alignment state of the liquid crystal.

[0184] 1, a light source 106 is disposed on the rear side of a liquid crystal light control element 102. The lighting device 100 is configured so that light emitted from the light source 106 is emitted to the front side of the drawing through the liquid crystal light control element 102. The liquid crystal light control element 102 has a first liquid crystal cell 10, a second liquid crystal cell 20, a third liquid crystal cell 30, and a fourth liquid crystal cell 40 disposed in this order from the light source 106 side.

[0185] Light source 106 includes a white light source, and an optical element such as a lens may be disposed between the white light source and liquid crystal light control element 102 as needed. The white light source is a light source that emits light similar to natural light, and may be one that emits dimmed light such as daylight white or warm white. Light source 106 is preferably configured as a light source with a narrow light distribution range, and preferably has a configuration in which, for example, an LED light source is combined with a reflector, a lens, etc.

[0186] As shown in the first to fourth embodiments, the illumination device 100 according to this embodiment is capable of controlling the intensity distribution of light emitted from the light source 106 by the liquid crystal light control element 102. That is, the intensity distribution of the illumination light in the polar angle direction can be controlled by a control signal input to the liquid crystal light control element 102. The illumination device 100 according to this embodiment can provide illumination with adjusted illuminance within the illumination surface. [Explanation of symbols]

[0187] 10: first liquid crystal cell, 20: second liquid crystal cell, 30: third liquid crystal cell, 40: fourth liquid crystal cell, 50: fifth liquid crystal cell, 60: sixth liquid crystal cell, 100: lighting device, 102: liquid crystal light control element, 104: circuit board, 106: light source, AL11: first alignment film, AL12: second alignment film, E11: first electrode, E12: second electrode, E11A: first strip electrode, E11B: second strip electrode, E12A: third strip electrode, E12B: fourth strip electrode, F1: first flexible wiring board, F2: second flexible wiring board, F3: third flexible wiring board, F4: fourth Flexible wiring board, LC1: first liquid crystal layer, LC2: second liquid crystal layer, LC3: third liquid crystal layer, LC4: fourth liquid crystal layer, LC5: fifth liquid crystal layer, LC6: sixth liquid crystal layer, LCM: liquid crystal molecule, PE11: first power supply line, PE12: second power supply line, PE13: third power supply line, PE14: fourth power supply line, PE15: fifth power supply line, PE16: sixth power supply line, PT11: first power supply terminal, PT12: second power supply terminal, SE: sealing material, S11: first substrate, S12: second substrate, T11: first connection terminal, T12: second connection terminal, T13: third connection terminal, T14: fourth connection terminal

Claims

1. a first liquid crystal cell, a second liquid crystal cell, a third liquid crystal cell, and a fourth liquid crystal cell; Each of the first to fourth liquid crystal cells is a first substrate and a second substrate facing the first substrate; a first electrode and a second electrode having a strip-shaped pattern provided on the first substrate; a third electrode and a fourth electrode having a strip-shaped pattern provided on the second substrate; a first alignment film provided on the first substrate; and a second alignment film provided on the second substrate. a liquid crystal layer between the first substrate and the second substrate; the strip-shaped patterns of the first electrodes and the second electrodes are alternately arranged, and the alignment direction of the first alignment film is provided so as to intersect with the extending direction of the strip-shaped patterns of the first electrodes and the second electrodes; the strip-shaped patterns of the third electrodes and the fourth electrodes are alternately arranged, and the alignment direction of the second alignment film is arranged to intersect with the extending direction of the strip-shaped patterns of the third electrodes and the fourth electrodes and also with the alignment direction of the first alignment film; the first to fourth liquid crystal cells are stacked in the order of the first liquid crystal cell, the second liquid crystal cell, the third liquid crystal cell, and the fourth liquid crystal cell from a light incident side to a light emitting side, Each of the first to fourth liquid crystal cells is arranged so that light is incident from the first substrate side. the extending directions of the first electrodes and the second electrodes of the first liquid crystal cell and the second liquid crystal cell are arranged parallel to a first direction, the extending directions of the first electrodes and the second electrodes of the third liquid crystal cell and the fourth liquid crystal cell are arranged parallel to a second direction intersecting the first direction, a voltage is applied to the first liquid crystal cell and the fourth liquid crystal cell so that the first electrode and the second electrode are at the same potential and a transverse electric field is formed between the third electrode and the fourth electrode; a voltage is applied to the second liquid crystal cell and the third liquid crystal cell so that a transverse electric field is formed between the first electrode and the second electrode, and the third electrode and the fourth electrode are set to the same potential; A liquid crystal light control element characterized by:

2. a first liquid crystal cell, a second liquid crystal cell, a third liquid crystal cell, a fourth liquid crystal cell, and a fifth liquid crystal cell; Each of the first to fifth liquid crystal cells is a first substrate and a second substrate facing the first substrate; a first electrode and a second electrode having a strip-shaped pattern provided on the first substrate; a third electrode and a fourth electrode having a strip-shaped pattern provided on the second substrate; a first alignment film provided on the first substrate; and a second alignment film provided on the second substrate. a liquid crystal layer between the first substrate and the second substrate; the strip-shaped patterns of the first electrodes and the second electrodes are alternately arranged, and the alignment direction of the first alignment film is provided so as to intersect with the extending direction of the strip-shaped patterns of the first electrodes and the second electrodes; the strip-shaped patterns of the third electrodes and the fourth electrodes are alternately arranged, and the alignment direction of the second alignment film is arranged to intersect with the extending direction of the strip-shaped patterns of the third electrodes and the fourth electrodes and also with the alignment direction of the first alignment film; the first to fifth liquid crystal cells are stacked in the order of the first liquid crystal cell, the second liquid crystal cell, the third liquid crystal cell, the fourth liquid crystal cell, and the fifth liquid crystal cell from a light incident side to a light emitting side, Each of the first to fifth liquid crystal cells is arranged so that light is incident from the first substrate side, the extending directions of the first electrodes and the second electrodes of the second liquid crystal cell and the third liquid crystal cell are arranged parallel to a first direction; the extending directions of the first electrodes and the second electrodes of the first liquid crystal cell, the fourth liquid crystal cell, and the fifth liquid crystal cell are arranged parallel to a second direction intersecting the first direction; A liquid crystal light control element characterized by:

3. a voltage is applied to the first liquid crystal cell, the second liquid crystal cell, and the fifth liquid crystal cell so that the first electrode and the second electrode are at the same potential and a transverse electric field is formed between the third electrode and the fourth electrode; 3. The liquid crystal light control element according to claim 2, wherein a voltage is applied to the third liquid crystal cell and the fourth liquid crystal cell so that a transverse electric field is formed between the first electrode and the second electrode, and the third electrode and the fourth electrode are at the same potential.

4. a first liquid crystal cell, a second liquid crystal cell, a third liquid crystal cell, a fourth liquid crystal cell, a fifth liquid crystal cell, and a sixth liquid crystal cell; Each of the first to sixth liquid crystal cells is a first substrate and a second substrate facing the first substrate; a first electrode and a second electrode having a strip-shaped pattern provided on the first substrate; a third electrode and a fourth electrode having a strip-shaped pattern provided on the second substrate; a first alignment film provided on the first substrate; and a second alignment film provided on the second substrate. a liquid crystal layer between the first substrate and the second substrate; the strip-shaped patterns of the first electrodes and the second electrodes are alternately arranged, and the alignment direction of the first alignment film is provided so as to intersect with the extending direction of the strip-shaped patterns of the first electrodes and the second electrodes; the strip-shaped patterns of the third electrodes and the fourth electrodes are alternately arranged, and the alignment direction of the second alignment film is arranged to intersect with the extending direction of the strip-shaped patterns of the third electrodes and the fourth electrodes and also with the alignment direction of the first alignment film; The first to sixth liquid crystal cells are arranged in the order from the light incident side to the light emitting side, namely, the first liquid crystal cell, the the second liquid crystal cell, the third liquid crystal cell, the fourth liquid crystal cell, the fifth liquid crystal cell, and the sixth liquid crystal cell are stacked in this order; Each of the first to sixth liquid crystal cells is arranged so that light is incident from the first substrate side, the extending directions of the first electrodes and the second electrodes of the first liquid crystal cell and the second liquid crystal cell are arranged parallel to a second direction; the extending directions of the first electrodes and the second electrodes of the third liquid crystal cell and the fourth liquid crystal cell are arranged parallel to a first direction intersecting with the second direction, the extending directions of the first electrodes and the second electrodes of the fifth liquid crystal cell and the sixth liquid crystal cell are arranged parallel to the second direction; A liquid crystal light control element characterized by:

5. a voltage is applied to the first liquid crystal cell, the fourth liquid crystal cell, and the fifth liquid crystal cell so that the third electrode and the fourth electrode have the same potential and a transverse electric field is formed between the first electrode and the second electrode; The liquid crystal light control element according to claim 4, wherein a voltage is applied to the second liquid crystal cell, the third liquid crystal cell, and the sixth liquid crystal cell so that a transverse electric field is formed between the first electrode and the second electrode, and the third electrode and the fourth electrode are at the same potential.

6. 6. The liquid crystal light control element according to claim 1, wherein the liquid crystal layer is a TN (twisted nematic) liquid crystal.

7. 6. An illumination device comprising: a liquid crystal light control element according to claim 1; and a light source, wherein the liquid crystal light control element is provided on an optical path of light emitted from the light source.

Images