Liquid crystal light control device

Abstract

To provide a liquid crystal light control device suppressing color breakup.SOLUTION: A liquid crystal light control device includes first to fourth liquid crystal cells. Each of the first to fourth liquid crystal cells includes: a first board in which a first electrode including a strip pattern is provided; a second board in which a second electrode including a strip pattern is provided; a first alignment layer provided in the first board; a second alignment layer provided in the second board; and a liquid crystal layer between the first board and the second board. The first electrode includes at least one first strip electrode having a strip pattern and at least one second strip electrode having a strip pattern, at least one first strip electrode and at least one second strip electrode are disposed separately and alternately, and the second electrode includes at least one third strip electrode having a strip pattern and at least one fourth strip electrode having a strip pattern. At least one third strip electrode and at least one fourth strip electrode are disposed separately and alternately.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] One embodiment of the present invention relates to an apparatus that utilizes the electro-optic effect of liquid crystals to control the distribution of light emitted from a light source. [Background technology]

[0002] There is a known technology for controlling the distribution of light emitted from a light source by using a liquid crystal lens. For example, a lighting device has been disclosed in which a liquid crystal cell having concentric ring electrodes controls the spread of light emitted from a light source (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

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

[0004] Since the refraction angle of light changes depending on the wavelength, when light emitted from a light source is diffused through a liquid crystal lens, a rainbow pattern may be visible on the outline of the illuminated area. This phenomenon is also called color breakup, and the degradation of the quality of the illumination light when it passes through a liquid crystal lens is a problem.

[0005] An object of one embodiment of the present invention is to provide a liquid crystal light control device in which color breakup is suppressed. [Means for solving the problem]

[0006] A liquid crystal light control device according to an embodiment of the present invention includes a first liquid crystal cell, a second liquid crystal cell overlapping the first liquid crystal cell, a third liquid crystal cell overlapping the second liquid crystal cell, and a fourth liquid crystal cell overlapping the third liquid crystal cell. Each of the first liquid crystal cell, the second liquid crystal cell, the third liquid crystal cell, and the fourth liquid crystal cell includes a first substrate on which a first electrode including a stripe pattern is provided, a second substrate on which a second electrode including a stripe pattern is provided, and a liquid crystal layer between the first substrate and the second substrate. The first substrate and the second substrate are arranged so that the longitudinal directions of the stripe patterns of the first electrode and the second electrode intersect, and among the first liquid crystal cell, the second liquid crystal cell, the third liquid crystal cell, and the fourth liquid crystal cell, two liquid crystal cells are arranged such that the longitudinal direction of the stripe pattern of the first electrode is parallel to the first direction, and the longitudinal directions of the stripe patterns of the first electrode of the other two liquid crystal cells are arranged such that the longitudinal direction of the stripe pattern of the first electrode is parallel to the second direction intersecting the first direction. [Brief description of the drawings]

[0007] [Figure 1] 1 is a perspective view showing a schematic configuration of a liquid crystal light control device according to an embodiment of the present invention; [Diagram 2] 1 shows a development view of a liquid crystal light control element constituting a liquid crystal light control device according to one embodiment of the present invention; [Diagram 3] 1 is a perspective view showing the arrangement of electrodes of a first liquid crystal cell, a second liquid crystal cell, a third liquid crystal cell and a fourth liquid crystal cell which constitute a liquid crystal light control element according to one embodiment of the present invention. [Figure 4A] 1 is a plan view showing electrodes provided on a first substrate of a liquid crystal cell constituting a liquid crystal light control element according to one embodiment of the present invention. [Figure 4B] 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. [Diagram 5] 1 is a diagram showing an example of a cross-sectional structure of a liquid crystal cell constituting a liquid crystal light control element according to one embodiment of the present invention. [Figure 6A] FIG. 2 is a diagram 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 6B]FIG. 2 is a diagram 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 6C] 1 is a diagram 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 waveform of a control signal applied to an electrode that drives the liquid crystal. [Figure 7A] FIG. 2 is a diagram for explaining the operation of a liquid crystal cell constituting a liquid crystal light control element according to one embodiment of the present invention, and shows a perspective view illustrating the arrangement of a first electrode and a second electrode. [Figure 7B] FIG. 2 is a diagram 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 to a first electrode. [Figure 7C] FIG. 2 is a diagram 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 to the second electrode. [Figure 8] FIG. 2 is a diagram illustrating a phenomenon in which a first polarized component and a second polarized component are diffused by two liquid crystal cells. [Figure 9] 5A to 5C are diagrams illustrating the operation of a liquid crystal light control device according to one embodiment of the present invention. [Figure 10A] 4 shows a voltage waveform applied to a liquid crystal cell in a liquid crystal light control device according to one embodiment of the present invention. [Figure 10B] 4 shows a voltage waveform applied to a liquid crystal cell in a liquid crystal light control device according to one embodiment of the present invention. [Figure 11A] 1 is a graph showing the angle dependence of chromaticity (x-coordinate axis) of a liquid crystal light control element according to one embodiment of the present invention and a liquid crystal light control element of a reference example. [Figure 11B] 1 is a graph showing the angle dependence of chromaticity (y coordinate axis) of a liquid crystal light control element according to one embodiment of the present invention and a liquid crystal light control element of a reference example. [Figure 12] 5A to 5C are diagrams illustrating the operation of a liquid crystal light control device according to one embodiment of the present invention. [Figure 13] 5A to 5C are diagrams illustrating the operation of a liquid crystal light control device according to one embodiment of the present invention. [Figure 14] 5A to 5C are diagrams illustrating the operation of a liquid crystal light control device according to one embodiment of the present invention. [Figure 15A] 1 shows an arrangement of a plurality of liquid crystal cells constituting a liquid crystal light control element according to one embodiment of the present invention, in which a first liquid crystal cell and a second liquid crystal cell are rotated by 90 degrees. [Figure 15B] 1 shows an arrangement of a plurality of liquid crystal cells constituting a liquid crystal light control element according to one embodiment of the present invention, in which a first liquid crystal cell and a third liquid crystal cell are rotated by 90 degrees. [Figure 16A] 1 shows an arrangement of a plurality of liquid crystal cells constituting a liquid crystal light control element according to one embodiment of the present invention, with the first to fourth liquid crystal cells each rotated by 90 degrees. [Figure 16B] 1 shows an arrangement of a plurality of liquid crystal cells constituting a liquid crystal light control element according to one embodiment of the present invention, in which a first liquid crystal cell and a third liquid crystal cell are inverted. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, the embodiments of the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different aspects, and should not be interpreted as being limited to the description of the embodiments exemplified below. In the drawings, the width, thickness, shape, etc. of each part may be shown schematically compared to the actual aspect in order to make the explanation clearer, but it is merely an example and does not limit the interpretation of the present invention. In this specification and each figure, elements similar to those described above with respect to the previous figures may be given the same reference numerals (or reference numerals with a, b, etc. added after the numerals) and detailed explanations may be omitted as appropriate. Furthermore, the letters "first" and "second" added to each element are convenient marks used to distinguish each element, and have no further meaning unless otherwise explained.

[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 on (or directly under) the other component or region, but also the case where it is above (or below) the other component or region, i.e., the case where another component is included between the component or region and above (or below) the other component or region.

[0010] 1 shows a perspective view of a liquid crystal light control device 100 according to one embodiment of the present invention. The liquid crystal light control device 100 includes a liquid crystal light control element 102 and a circuit board 104. The liquid crystal light control element 102 includes a plurality of liquid crystal cells. In this embodiment, the liquid crystal light control element 102 includes at least four liquid crystal cells.

[0011] 1 shows an embodiment in which a 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. 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 flat panels, and are arranged so that the flat surfaces of the respective liquid crystal cells overlap. Transparent adhesive layers (not shown) are provided between the first liquid crystal cell 10 and the second liquid crystal cell 20, between the second liquid crystal cell 20 and the third liquid crystal cell 30, 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 liquid crystal cells arranged adjacent to each other in the front and rear are bonded to each other with transparent adhesive layers.

[0012] 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 for controlling the alignment state of the liquid crystal to each liquid crystal cell via the flexible wiring boards.

[0013] 1, a light source unit 106 is disposed on the rear side of a liquid crystal light control element 102. The liquid crystal light control element 100 is configured so that light emitted from the light source unit 106 is emitted to the front side of the drawing through the liquid crystal light control element 102. In the liquid crystal light control element 102, 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 disposed in this order from the light source unit 106 side.

[0014] The light source unit 106 includes a white light source, and an optical element such as a lens may be disposed between the white light source and the liquid crystal light control element 102 as necessary. The white light source is a light source that emits light close to natural light, and may emit dimmed light such as daylight white or incandescent light. The liquid crystal light control device 100 has a function of controlling the diffusion direction of light emitted from the light source unit 106 by the liquid crystal light control element 102. The liquid crystal light control element 102 has a function of shaping the light emitted from the light source unit 106 into a light distribution pattern such as a square, cross, or line shape.

[0015] Fig. 2 shows an exploded view of the liquid crystal light control element 102 shown in Fig. 1. The liquid crystal light control element 102 includes 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.

[0016] The first liquid crystal cell 10 includes a first substrate S11 and a second substrate S12. The first substrate S11 and the second substrate S12 are disposed facing each other with a gap therebetween. A liquid crystal layer (not shown) is provided in the gap between the first substrate S11 and the second substrate S12. The first flexible wiring substrate F1 is connected to the first substrate S11.

[0017] The second liquid crystal cell 20 includes a first substrate S21, a second substrate S22, and a second flexible wiring substrate F2, and has a similar configuration to the first liquid crystal cell 10. The third liquid crystal cell 30 includes a first substrate S31, a second substrate S32, and a third flexible wiring substrate F3, and has a similar configuration to the first liquid crystal cell 10. The fourth liquid crystal cell 40 includes a first substrate S41, a second substrate S42, and a fourth flexible wiring substrate F4, and has a similar configuration to the first liquid crystal cell 10.

[0018] A first transparent adhesive layer TA1 is disposed between the first liquid crystal cell 10 and the second liquid crystal cell 20. The first transparent adhesive layer TA1 transmits visible light and bonds the second substrate S12 of the first liquid crystal cell 10 and the first substrate S21 of the second liquid crystal cell 20. A second transparent adhesive layer TA2 is disposed between the second liquid crystal cell 20 and the third liquid crystal cell 30. The second transparent adhesive layer TA2 transmits visible light and bonds the second substrate S22 of the second liquid crystal cell 20 and the first substrate S31 of the third liquid crystal cell 30. A third transparent adhesive layer TA3 is disposed between the third liquid crystal cell 30 and the fourth liquid crystal cell 40. The third transparent adhesive layer TA3 transmits visible light and bonds the second substrate S32 of the third liquid crystal cell 30 and the first substrate S41 of the fourth liquid crystal cell 40.

[0019] The first transparent adhesive layer TA1, the second transparent adhesive layer TA2, and the third transparent adhesive layer TA3 preferably have high transmittance and refractive index close to that of the first substrate S11, S21, S31, and S41 and the second substrate S12, S22, S23, and S24. The first transparent adhesive layer TA1, the second transparent adhesive layer TA2, and the third transparent adhesive layer TA3 may be made of an optical elastic resin, for example, an adhesive containing an acrylic resin having translucency. In addition, since the temperature of the liquid crystal light control element 102 increases due to heat radiated from the light source unit 106, it is preferable that the thermal expansion coefficient of the first transparent adhesive layer TA1, the second transparent adhesive layer TA2, and the third transparent adhesive layer TA3 have a value close to that of the first substrate and the second substrate.

[0020] However, since the thermal expansion coefficients of the first transparent adhesive layer TA1, the second transparent adhesive layer TA2, and the third transparent adhesive layer TA3 are often higher than that of, for example, a glass substrate, it is necessary to consider stress relaxation when the temperature rises. The thicknesses of the first transparent adhesive layer TA1, the second transparent adhesive layer TA2, and the third transparent adhesive layer TA3 are preferably thicker than the cell gaps (thicknesses of the liquid crystal layers) of the liquid crystal cells (first liquid crystal cell 10, second liquid crystal cell 20, third liquid crystal cell 30, fourth liquid crystal cell 40) in order to relax thermal stress when the temperature rises.

[0021] As described later, 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 have substantially the same structure. The liquid crystal light control element 102 according to this embodiment has a structure in which the third liquid crystal cell 30 and the fourth liquid crystal cell 40 are overlapped with the first liquid crystal cell 10 and the second liquid crystal cell 20 in a state rotated by 90 degrees. In other words, the liquid crystal light control element 102 according to this embodiment includes a plurality of liquid crystal cells, and includes a structure in which at least one liquid crystal cell and another liquid crystal cell adjacent to (overlapping) the at least one liquid crystal cell are arranged in a state rotated in a range of 90±10 degrees. The rotation angles of the third liquid crystal cell 30 and the fourth liquid crystal cell 40 can be set in a range of 90±10 degrees.

[0022] In Fig. 2, the third liquid crystal cell 30 and the fourth liquid crystal cell 40 are arranged in a state rotated by 90 degrees when the arrangement of the first liquid crystal cell 10 and the second liquid crystal cell 20 is taken as the reference. On the other hand, when the third liquid crystal cell 30 and the fourth liquid crystal cell 40 are taken as the reference, it can be said that the first liquid crystal cell 10 and the second liquid crystal cell 20 are arranged in a state rotated by 90 degrees. By stacking a plurality of liquid crystal cells having the same electrode pattern and rotating some of the liquid crystal cells, it is possible to change the electrode arrangement and to change the diffusion of light passing through the stacked liquid crystal cells. The details are explained below.

[0023] FIG. 3 is a perspective view showing the arrangement of electrodes provided in each of 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. As shown in FIG.

[0024] 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. The first substrate S11 has a first electrode E11 on a surface facing the first liquid crystal layer LC1, and the second substrate S12 has a second electrode E12 on a surface facing the first liquid crystal layer LC1. The first electrode E11 and the second electrode E12 are disposed so as to face each other with the first liquid crystal layer LC1 in between. As described above, the first substrate S11 and the second substrate S12 face each other, and it is also possible to define the facing surface as an inner surface and the surface opposite the inner surface as an outer surface. In this case, the first electrode E11 is provided on the inner surface of the first substrate, and the second electrode E12 is provided on the inner surface of the second substrate.

[0025] The first electrode E11 includes a plurality of first strip-shaped electrodes E11A formed in strips and a plurality of second strip-shaped electrodes E11B formed in strips. The second electrode E12 includes a plurality of third strip-shaped electrodes E12A formed in strips and a plurality of fourth strip-shaped electrodes E12B formed in strips. The plurality of first strip-shaped electrodes 11A and the plurality of second strip-shaped electrodes E11B are alternately arranged, and the plurality of third strip-shaped electrodes 12A and the plurality of fourth strip-shaped electrodes E12B are alternately arranged.

[0026] 3 shows the X, Y, and Z axis directions for the sake of explanation. 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 to be stacked in the Z axis direction. In the first liquid crystal cell 10, the longitudinal direction of the first strip electrodes E11A and the second strip electrodes E11B is arranged in a direction parallel to the Y axis direction, and the longitudinal direction of the third strip electrodes 12A and the fourth strip electrodes E12B is arranged in a direction parallel to the X axis direction. That is, the first strip electrodes E11A and the second strip electrodes E11B are arranged to intersect with the third strip electrodes E12A and the fourth strip electrodes E12B. The longitudinal direction of the first strip electrodes E11A and the second strip electrodes E11B and the longitudinal direction of the third strip electrodes E12A and the fourth strip electrodes E12B can be arranged to intersect within a range of 90 degrees ±10 degrees, for example, and are preferably arranged to be perpendicular (90 degrees). In this embodiment, these longitudinal directions are perpendicular to each other.

[0027] The second liquid crystal cell 20 includes a first substrate S21, a second substrate S22, and a second liquid crystal layer LC2 between the first substrate S21 and the second substrate S22. The first substrate S21 is provided with a first electrode E21 on a surface facing the second liquid crystal layer LC2, and the second substrate S22 is provided with a second electrode E22 on a surface facing the second liquid crystal layer LC2. The first electrode E21 includes a plurality of first strip-shaped electrodes E21A formed in strips and a plurality of second strip-shaped electrodes E21B formed in strips, and the second electrode E22 includes a plurality of third strip-shaped electrodes E22A formed in strips and a plurality of fourth strip-shaped electrodes E22B formed in strips.

[0028] In the second liquid crystal cell 20, a plurality of first strip electrodes 21A and a plurality of second strip electrodes E21B are alternately arranged, and a plurality of third strip electrodes 22A and a plurality of fourth strip electrodes E22B are alternately arranged. In the second liquid crystal cell 20, the longitudinal direction of the plurality of first strip electrodes 21A and the plurality of second strip electrodes E21B is arranged in a direction parallel to the Y-axis direction, and the longitudinal direction of the plurality of third strip electrodes 22A and the plurality of fourth strip electrodes E22B is arranged in a direction parallel to the X-axis direction. That is, the plurality of first strip electrodes E21A and the plurality of second strip electrodes E21B are arranged to intersect with the plurality of third strip electrodes E22A and the plurality of fourth strip electrodes E22B. The longitudinal direction of the first strip electrodes E21A and the second strip electrodes E21B and the longitudinal direction of the third strip electrodes E22A and the fourth strip electrodes E22B can be arranged to intersect within a range of 90 degrees ±10 degrees, for example, and are preferably arranged to be perpendicular (90 degrees). In this embodiment, these longitudinal directions are perpendicular to each other.

[0029] The third liquid crystal cell 30 includes a first substrate S31, a second substrate S32, and a third liquid crystal layer LC3 between the first substrate S31 and the second substrate S32. The first substrate S31 is provided with a first electrode E31 on a surface facing the third liquid crystal layer LC3, and the second substrate S32 is provided with a second electrode E32 on a surface facing the third liquid crystal layer LC3. The first electrode E31 includes a plurality of first strip-shaped electrodes E31A formed in strips and a plurality of second strip-shaped electrodes E31B formed in strips, and the second electrode E32 includes a plurality of third strip-shaped electrodes E32A formed in strips and a plurality of fourth strip-shaped electrodes E32B formed in strips.

[0030] In the third liquid crystal cell 30, a plurality of first strip electrodes 31A and a plurality of second strip electrodes E31B are alternately arranged, and a plurality of third strip electrodes 32A and a plurality of fourth strip electrodes E32B are alternately arranged. In the third liquid crystal cell 30, the longitudinal direction of the plurality of first strip electrodes 31A and the plurality of second strip electrodes E31B is arranged in a direction parallel to the X-axis direction, and the longitudinal direction of the plurality of third strip electrodes 32A and the plurality of fourth strip electrodes E32B is arranged in a direction parallel to the Y-axis direction. That is, the plurality of first strip electrodes E31A and the plurality of second strip electrodes E31B are arranged to intersect with the plurality of third strip electrodes E32A and the plurality of fourth strip electrodes E32B. The longitudinal direction of the first strip electrodes E31A and the second strip electrodes E31B and the longitudinal direction of the third strip electrodes E32A and the fourth strip electrodes E32B can be arranged to intersect within a range of 90 degrees ±10 degrees, for example, and are preferably arranged to be perpendicular (90 degrees). In this embodiment, these longitudinal directions are perpendicular to each other.

[0031] The fourth liquid crystal cell 40 includes a first substrate S41, a second substrate S42, and a fourth liquid crystal layer LC4 between the first substrate S41 and the second substrate S42. The first substrate S41 has a first electrode E41 on a surface facing the fourth liquid crystal layer LC4, and the second substrate S42 has a second electrode E42 on a surface facing the fourth liquid crystal layer LC4. The first electrode E41 includes a plurality of first strip-shaped electrodes E41A and a plurality of second strip-shaped electrodes E41B, and the second electrode E42 includes a plurality of third strip-shaped electrodes E42A and a plurality of fourth strip-shaped electrodes E42B. In this embodiment, the longitudinal directions of these electrodes are perpendicular to each other.

[0032] In the fourth liquid crystal cell 40, a plurality of first strip electrodes 41A and a plurality of second strip electrodes E41B are alternately arranged, and a plurality of third strip electrodes 42A and a plurality of fourth strip electrodes E42B are alternately arranged. In the fourth liquid crystal cell 40, the longitudinal direction of the plurality of first strip electrodes 41A and the plurality of second strip electrodes E41B is arranged in a direction parallel to the X-axis direction, and the longitudinal direction of the plurality of third strip electrodes 42A and the plurality of fourth strip electrodes E42B is arranged in a direction parallel to the Y-axis direction. That is, the plurality of first strip electrodes E41A and the plurality of second strip electrodes E41B are arranged to intersect with the plurality of third strip electrodes E42A and the plurality of fourth strip electrodes E42B. The longitudinal direction of the first strip electrodes E41A and the second strip electrodes E41B and the longitudinal direction of the third strip electrodes E42A and the fourth strip electrodes E42B can be arranged to intersect within a range of 90 degrees ±10 degrees, for example, and are preferably arranged to be perpendicular (90 degrees). In this embodiment, these longitudinal directions are perpendicular to each other.

[0033] As is clear from the above description, in the liquid crystal light control element 102, the first strip electrodes E11A and the second strip electrodes E11B of the first liquid crystal cell 10 and the first strip electrodes E21A and the second strip electrodes E21B of the second liquid crystal cell 20 are arranged in the same longitudinal direction, and the first strip electrodes E31A and the second strip electrodes E31B of the third liquid crystal cell 30 and the first strip electrodes E41A and the second strip electrodes E41B of the fourth liquid crystal cell 40 are arranged in the same longitudinal direction. The first strip electrodes E11A and the second strip electrodes E11B of the first liquid crystal cell 10, the first strip electrodes E21A and the second strip electrodes E21B of the second liquid crystal cell 20, the first strip electrodes E31A and the second strip electrodes E31B of the third liquid crystal cell 30, and the first strip electrodes E41A and the second strip electrodes E41B of the fourth liquid crystal cell 40 are arranged so that their longitudinal directions intersect. In this embodiment, the intersection angle is 90 degrees.

[0034] Similarly, in the liquid crystal light control element 102, the third strip electrodes E12A and the fourth strip electrodes E12B of the first liquid crystal cell 10 and the third strip electrodes E22A and the fourth strip electrodes E22B of the second liquid crystal cell 20 are arranged in the same longitudinal direction, and the third strip electrodes E32A and the fourth strip electrodes E32B of the third liquid crystal cell 30 and the third strip electrodes E42A and the fourth strip electrodes E42B of the fourth liquid crystal cell 40 are arranged in the same longitudinal direction. The third strip electrodes E12A and the fourth strip electrodes E12B of the first liquid crystal cell 10, the third strip electrodes E22A and the fourth strip electrodes E22B of the second liquid crystal cell 20, the third strip electrodes E32A and the fourth strip electrodes E32B of the third liquid crystal cell 30, and the third strip electrodes E42A and the fourth strip electrodes E42B of the fourth liquid crystal cell 40 are arranged so that their longitudinal directions intersect. In this case, the crossing angle is preferably in the range of 90 degrees ±10 degrees, and is more preferably perpendicular (90 degrees). In this embodiment, the crossing angle is 90 degrees.

[0035] That is, in the liquid crystal light control element 102 according to this embodiment, the first electrodes E11 and E21 of the first liquid crystal cell 10 and the second liquid crystal cell 20 have a longitudinal direction of a belt-like pattern parallel to the Y-axis direction, and the first electrodes E31 and E41 of the third liquid crystal cell 30 and the fourth liquid crystal cell 40 have a longitudinal direction of a belt-like pattern parallel to the X-axis direction. In other words, the longitudinal direction of the belt-like pattern of the first electrodes E11 and E21 of the first liquid crystal cell 10 and the second liquid crystal cell 20 is arranged so as to intersect with the longitudinal direction of the belt-like pattern of the first electrodes E31 and E41 of the third liquid crystal cell 30 and the fourth liquid crystal cell 40. As described above, the crossing angle at this time is preferably in the range of 90 degrees ± 10 degrees, and more preferably perpendicular (90 degrees). In this embodiment, the crossing angle is 90 degrees.

[0036] The first electrode E11 and the second electrode E12 provided in the first liquid crystal cell 10, the first electrode E21 and the second electrode E22 provided in the second liquid crystal cell 20, the first electrode E31 and the second electrode E32 provided in the third liquid crystal cell 30, and the first electrode E41 and the second electrode E42 provided in the fourth liquid crystal cell 40 have substantially the same size in a plan view. Although not shown in Fig. 3, the light source section (106) is disposed below the first liquid crystal cell 10. The light emitted from the light source section (106) and incident on the liquid crystal light control element 102 passes through all of 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 before being emitted.

[0037] 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 have substantially the same configuration, but below, the first liquid crystal cell 10 will be described in more detail as a representative.

[0038] Fig. 4A shows a plan view of the first substrate S11, and Fig. 4B shows a plan view of the second substrate S12. Note that Fig. 4B is a plan view of the second substrate S12 as viewed from the inner surface side.

[0039] As shown in Fig. 4A, a first electrode E11 is provided on a first substrate S11. The first electrode E11 includes a plurality of first strip-shaped electrodes E11A and a plurality of second strip-shaped electrodes E11B. The plurality of first strip-shaped electrodes E11A and the plurality of second strip-shaped electrodes E11B have strip-shaped patterns. The strip-shaped patterns of the plurality of first strip-shaped electrodes E11A and the strip-shaped patterns of the plurality of second strip-shaped electrodes E11B are alternately arranged at a predetermined interval in a direction intersecting the longitudinal direction.

[0040] The first strip-shaped electrodes E11A are each connected to a first power supply line PL11, and the second strip-shaped electrodes E11B are each connected to a second power supply line PL12. The first power supply line PL11 is connected to a first connection terminal T11, and the second power supply line PL12 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 end 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 PL15. The fifth power supply line PL15 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 PL16. The sixth power supply line PL16 is connected to a second power supply terminal PT12 provided at a predetermined position on the surface of the first substrate S11.

[0041] The first strip electrodes E11A are connected to a first power supply line PL11, and the same voltage is applied to the second strip electrodes E11B. The second strip electrodes E11B are connected to a second power supply line PL12, and the same voltage is applied to the first strip electrodes E11A and the second strip electrodes E11B. As shown in FIG. 4A, the first strip electrodes E11A and the second strip electrodes E11B are alternately arranged. The first strip electrodes E11A and the second strip electrodes E11B are electrically separated. When voltages of different levels are applied to the first strip electrodes E11A and the second strip electrodes E11B, an electric field is generated between the two electrodes due to the potential difference. That is, a horizontal electric field can be generated by the first strip electrodes E11A and the second strip electrodes E11B.

[0042] As shown in Fig. 4B, the second electrode E12 is provided on the second substrate S12. The second electrode E12 includes a plurality of third strip-shaped electrodes E12A and a plurality of fourth strip-shaped electrodes E12B. The plurality of third strip-shaped electrodes E12A and the plurality of fourth strip-shaped electrodes E12B have a strip-shaped pattern. The strip-shaped pattern of the plurality of third strip-shaped electrodes E12A and the strip-shaped pattern of the plurality of fourth strip-shaped electrodes E12B are alternately arranged at a predetermined interval in a direction intersecting the longitudinal direction.

[0043] The multiple third strip-shaped electrodes E12A are each connected to a third power supply line PL13, and the multiple fourth strip-shaped electrodes E12B are each connected to a fourth power supply line PL14. The third power supply line PL13 is connected to a third power supply terminal PT13, and the fourth power supply line PL14 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 of the first substrate S11, and the fourth power supply terminal PT14 is provided at a position corresponding to the second power supply terminal PT12 of the first substrate S11.

[0044] The third strip electrodes E12A are connected to a third power supply line PL13, and the same voltage is applied to the fourth strip electrodes E12B. The fourth strip electrodes E12B are connected to a fourth power supply line PL14, and the same voltage is applied to the third strip electrodes E12A and the fourth strip electrodes E12B. As shown in FIG. 4B, the third strip electrodes E12A and the fourth strip electrodes E12B are alternately arranged. The third strip electrodes E12A and the fourth strip electrodes E12B are electrically separated from each other. When voltages of different levels are applied to the third strip electrodes E12A and the fourth strip electrodes E12B, an electric field is generated between the two electrodes due to the potential difference. That is, a horizontal electric field can be generated by the third strip electrodes E12A and the fourth strip electrodes E12B.

[0045] The first connection terminal T11, the second connection terminal T12, the third connection terminal 13, and the fourth connection terminal T14 provided on the first substrate S11 are terminals connected to the flexible wiring substrate. 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 to a conductive material.

[0046] Fig. 5 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. 5 shows a cross-sectional structure corresponding to the A1-A2 line of the first substrate S11 shown in Fig. 4A and the second substrate S12 shown in Fig. 4B.

[0047] The first liquid crystal cell 10 has an effective area AA capable of polarizing and scattering incident light. 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. A gap is provided between the first substrate S11 and the second substrate S12 in which a first liquid crystal layer LC1 is sealed. The first liquid crystal layer LC1 is sealed between the first substrate S11 and the second substrate S12 by the sealant SE.

[0048] The first substrate S11 has a first electrode E11 and a first power supply terminal PT11, and has a structure in which a first alignment film AL11 is provided on the first electrode E11. The first electrode E11 includes a first strip-shaped electrode E11A and a second strip-shaped electrode E11B. The first power supply terminal PT11 has a structure that continues from the fifth power supply line PL15, and is disposed outside the seal material SE.

[0049] The second substrate S12 has a second electrode E12 and a third power supply terminal PT13, and has a structure in which a second alignment film AL12 is provided on the second electrode E12. The second electrode E12 includes a third strip-shaped electrode E12A and a fourth strip-shaped electrode E12B. The third power supply terminal PT13 has a structure that continues from the third power supply line PL13, and is disposed outside the seal material SE.

[0050] The first electrode E11 and the second electrode E12 are arranged so that the longitudinal direction of the strip-shaped electrode pattern intersects. That is, the longitudinal direction of the first strip-shaped electrode E11A and the second strip-shaped electrode E11B intersects with the longitudinal direction of the third strip-shaped electrode E12A and the fourth strip-shaped electrode E12B. In this embodiment, the first strip-shaped electrode E11A and the second strip-shaped electrode E11B intersect with the third strip-shaped electrode E12A and the fourth strip-shaped electrode E12B at an angle of 90 degrees. The intersection angle between the first electrode E11 and the second electrode E12 can be set to, for example, 90 degrees ± 10 degrees as described above.

[0051] The first power supply terminal PT11 and the third power supply terminal PT13 face each other and are arranged so as to face each other in an area outside the sealing material SE. The first conductive member CP11 is arranged between the first power supply terminal PT11 and the third power supply terminal PT13 and electrically connects them. The first conductive member CP11 can be formed of a conductive paste material, for example, silver paste or carbon paste. Although not shown in FIG. 5, the second power supply terminal PT12 and the fourth power supply terminal PT14 are also electrically connected by a conductive member in a similar manner.

[0052] The first substrate S11 and the second substrate S12 are light-transmitting substrates, such as glass substrates and resin substrates. The first electrode E11 and the second electrode E12 are transparent electrodes formed of transparent conductive materials such as indium tin oxide (ITO) and indium zinc oxide (IZO). The power supply lines (first power supply line PL11, second power supply line PL12, third power supply line PL13, fourth power supply line PL14, fifth power supply line PL15, sixth power supply line PL16), 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 formed of metal materials such as aluminum, titanium, molybdenum, and tungsten. The power feed lines (first power feed line PL11, second power feed line PL12, third power feed line PL13, fourth power feed line PL14, fifth power feed line PL15, sixth power feed line PL16) may be formed of the same transparent conductive film as the first electrode E11 and the second electrode E12. The alignment films AL1 and AL2 are formed of a horizontal alignment film having an alignment regulating force substantially parallel to the main plane of the substrate. The first liquid crystal layer LC1 is made of, for example, twisted nematic liquid crystal (TN (Twisted Nematic) liquid crystal). Although not shown in FIG. 5, a spacer may be provided between the first substrate S11 and the second substrate S12 to keep the distance between the two substrates constant.

[0053] Next, the electro-optical action in the first liquid crystal cell 10 will be described with reference to Figures 6A, 6B, 6C, 7A, 7B, 7C, and 8. Note that Figures 6 to 8 show only the configuration necessary for the description.

[0054] Fig. 6A shows a partial schematic cross-sectional structure of the first liquid crystal cell 10. Fig. 6B shows the first strip electrodes E11A and second strip electrodes E11B, which are provided on the first substrate S11, the first alignment film AL11, the second alignment film AL12, which is provided on the second substrate S12, and the first liquid crystal layer LC1. In Fig. 6A, the third strip electrodes E12A and the fourth strip electrodes E12B are omitted for the sake of simplicity.

[0055] FIG. 6A shows that the orientation direction of the first orientation film AL11 is different from that of the second orientation film AL12. Specifically, the first orientation film AL11 is oriented in a direction ALD1 that intersects with the longitudinal direction of the first strip electrode E11A and the second strip electrode E11B at an angle of 90 degrees as shown in FIG. 4A, and the second orientation film AL12 is oriented in a direction ALD2 that intersects with the longitudinal direction of the third strip electrode E12A and the fourth strip electrode E12B at an angle of 90 degrees as shown in FIG. 4B. Therefore, in the first liquid crystal cell 10 shown in FIG. 6A, the first orientation film AL11 is oriented in the left-right direction of the paper, and the second orientation film AL12 is oriented in the normal direction of the paper. The orientation may be a rubbing process or a light distribution process. The orientation direction of the orientation film can be set within a range of 90 degrees ±10 degrees with respect to the extension direction of the strip electrodes.

[0056] A TN liquid crystal is used for the first liquid crystal layer LC1. Since the alignment direction ALD1 of the first alignment film AL11 and the alignment direction ALD2 of the second alignment film AL12 are perpendicular to each other, the liquid crystal molecules of the first liquid crystal layer LC1 are aligned such that the long axis direction of the liquid crystal molecules is twisted by 90 degrees from the first alignment film AL11 to the second alignment film AL12 in a state where they are not affected by an external electric field. Fig. 6A shows a state where no voltage is applied to the first strip-shaped electrodes E11A and the second strip-shaped electrodes E11B, and shows a state where the long axis direction of the liquid crystal molecules is aligned with a twist of 90 degrees.

[0057] 6A shows an example in which the liquid crystal layer LC1 is formed of positive-type twisted nematic liquid crystal (TN liquid crystal) and the long axes of the liquid crystal molecules are oriented in the same direction as the orientation direction of the alignment film, but negative-type liquid crystal can be used by rotating the orientation direction of the alignment film by 90 degrees, that is, by aligning the orientation direction of each alignment film AL11, AL12 with the extension direction of the strip electrodes E11A, E12A of each substrate S11, S12. The liquid crystal preferably contains a chiral agent that imparts a twist to the liquid crystal molecules.

[0058] 6B shows a state in which a low-level voltage VL is applied to the first strip electrode E11A and a high-level voltage VH is applied to the second strip electrode E11B. In this state, a horizontal electric field is generated between the first strip electrode E11A and the second strip electrode E11B. As shown in FIG. 6B, the alignment direction of the liquid crystal molecules on the first substrate S11 side is changed by the influence of the horizontal electric field. For example, the alignment of the liquid crystal molecules on the first substrate S11 side is changed so that the long axis direction is parallel to the direction of the electric field.

[0059] The values ​​of the low-level voltage VL and the high-level voltage VH applied to the first strip electrode E11A and the second strip electrode E11B are appropriately set. For example, 0V is applied as the low-level voltage VL1, and a voltage of 5 to 30V is applied as the high-level voltage VH1. A voltage in which the low-level voltage VL and the high-level voltage VH alternate is applied to the first strip electrode E11A and the second strip electrode E11B. For example, as shown in FIG. 6C, the voltage may be applied so that the voltage levels are synchronized and periodically changed between the two electrodes, such that in a certain period, the low-level voltage VL is applied to the first strip electrode E11A and the high-level voltage VH is applied to the second strip electrode E11B, and in the next certain period, the high-level voltage VH is applied to the first strip electrode E11A and the low-level voltage VL is applied to the second strip electrode E11B.

[0060] By alternately applying a low-level voltage VL and a high-level voltage VH to the first strip-shaped electrodes E11A and the second strip-shaped electrodes E11B, an alternating electric field is generated, and deterioration of the first liquid crystal layer LC1 is suppressed. Note that the frequency of the voltage applied to the first strip-shaped electrodes E11A and the second strip-shaped electrodes E11B may be any frequency that allows the liquid crystal molecules to follow changes in the electric field, and may be, for example, 15 to 100 Hz.

[0061] Fig. 7A is a partial perspective view of the first liquid crystal cell 10, showing the arrangement of the first strip electrodes E11A and the second strip electrodes E11B, the third strip electrodes E12A and the fourth strip electrodes E12B, and the first liquid crystal layer LC1. Figs. 7B and 7C show schematic cross-sectional views of the first liquid crystal cell 10. Fig. 7B shows a schematic cross-sectional view of the first liquid crystal cell 10 shown in Fig. 7A when viewed from side A in the figure, and Fig. 7C shows a schematic cross-sectional view of the first liquid crystal cell 10 shown in Fig. 7A when viewed from side B in the figure. Figs. 7B and 7C 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.

[0062] As shown in FIG. 7A and FIG. 7C, 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. This center-to-center distance W has a relationship of W=a+b, where a is the width a of the first strip electrode E11A shown in FIG. 7A and a distance b from the end of the first strip electrode E11A to the end of the second strip electrode E11B. Also, the first strip electrode E11A and the second strip electrode E11B are spaced apart from the third strip electrode E12A and the fourth strip electrode E12B and are arranged to face each other in a perpendicular state. The first substrate S11 and the second substrate S12 are arranged to face each other with a distance D, which is substantially equivalent to the thickness of the liquid crystal layer LC1. In reality, a first strip electrode E11A and a first alignment film AL11 are provided on the first substrate S11, and a third strip electrode E12A and a second alignment film AL12, etc. are provided on the second substrate S12, but since the thicknesses of these electrodes and alignment films are sufficiently small compared to the size of the gap D, the thickness of the liquid crystal layer LC1 can be considered to be the same as the gap D.

[0063] In the first liquid crystal cell 10, the distance D between the strip electrodes sandwiching the first liquid crystal layer LC1 is preferably equal to or greater than the center-to-center distance W of the strip electrodes. That is, the distance D is preferably equal to or greater than the center-to-center distance W. For example, the distance D is preferably equal to or greater than the center-to-center distance W of the strip electrodes. When the width of the first strip electrode E11A is 5 μm, the width a of the first strip electrode E11A and the second strip electrode E11B is 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 is preferably equal to or greater than 10 μm.

[0064] Such a relationship between the center distance W of the strip electrodes and the above-mentioned interval D makes it possible to prevent the electric field generated by the first strip electrodes E11A and the second strip electrodes E11B and the electric field generated by the third strip electrodes E12A and the fourth strip electrodes E12B from interfering with each other. That is, as shown in Fig. 7B, the first strip electrodes E11A and the second strip electrodes E11B can control the orientation of liquid crystal molecules in their vicinity without being influenced by the third strip electrodes E12A and the fourth strip electrodes E12B, and as shown in Fig. 7C, the third strip electrodes E12A and the fourth strip electrodes E12B can control the orientation of liquid crystal molecules in their vicinity without being influenced by the first strip electrodes E11A and the second strip electrodes E11B.

[0065] It is known that the refractive index of liquid crystal changes depending on the orientation state. As shown in FIG. 6A, 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 aligned in a state twisted by 90 degrees from the first substrate S11 side to the second substrate S12 side. The liquid crystal layer LC1 has a nearly uniform refractive index distribution in this orientation state. Therefore, the first polarized component PL1 of the light incident on the first liquid crystal cell 10 and the second polarized component PL2 perpendicular to the first polarized component PL1 (see FIG. 8) are rotated by the influence of the initial orientation of the liquid crystal molecules, but are transmitted through the first liquid crystal layer LC1 with almost no refraction (or scattering). Here, the first polarized component PL1 corresponds to, for example, P-polarized light of natural light, and the second polarized component corresponds to, for example, S-polarized light.

[0066] On the other hand, as shown in Fig. 6B, in the ON state where a voltage is applied to the first strip electrodes E11A and the second strip electrodes E11B to form an electric field, if the first liquid crystal layer LC1 has positive dielectric anisotropy, the liquid crystal molecules are aligned with their major axes along the electric field. As a result, as shown in Fig. 6B, the first liquid crystal layer LC1 is formed with regions in which the liquid crystal molecules rise almost vertically above the first strip electrodes E11A and the second strip electrodes E11B, regions in which the liquid crystal molecules are aligned obliquely along the distribution of the electric field between the first strip electrodes E11A and the second strip electrodes E11B, and regions in which the initial alignment state is relatively maintained away from the first strip electrodes E11A and the second strip electrodes E11B.

[0067] As shown in Fig. 6B, between the first strip electrode E11A and the second strip electrode E11B, the long axis of the liquid crystal molecules is aligned in a convex arc shape along the direction of the electric field. That is, as shown in Fig. 6A and Fig. 6B, the initial alignment direction of the liquid crystal molecules is the same as the direction of the horizontal electric field generated between the first strip electrode E11A and the second strip electrode E11B, and as shown in Fig. 6B, the alignment direction of the liquid crystal molecules located approximately at the center between the two electrodes hardly changes, but the liquid crystal molecules located from the center to each electrode side are aligned inclined (tilted) in the normal direction to the surface of the first substrate S11 according to the intensity distribution of the electric field. Therefore, when the liquid crystal on the first substrate S11 side is viewed as a whole, the liquid crystal molecules are aligned in an arc shape between the first strip electrode E11A and the second strip electrode E11B.

[0068] As a result, an arc-shaped dielectric constant distribution is formed in the liquid crystal layer LC1, and incident light (polarized components parallel to the direction of the initial alignment of the liquid crystal molecules) is diffused radially. On the second substrate S12 side, a similar phenomenon occurs due to the third strip-shaped electrodes E12Aa and fourth strip-shaped electrodes E12B arranged perpendicular to the electrodes of the first substrate S11 (see FIG. 7C), and incident light (polarized components parallel to the direction of the initial alignment of the liquid crystal molecules on the second substrate S12 side) is diffused radially.

[0069] As described with reference to Figures 7B and 7C, since the liquid crystal layer LC1 is sufficiently thick, the diffusion of different polarized components can be controlled independently on the first substrate S11 side and the second substrate S12 side.

[0070] The liquid crystal molecules have a refractive index anisotropy Δn. Therefore, the first liquid crystal layer LC1 in the on state has a refractive index distribution or retardation distribution according to the alignment state of the liquid crystal molecules. Here, the retardation is expressed as Δn·d, where d is the thickness of the first liquid crystal layer LC1. In the on state, the first polarized component PL1 is scattered by the influence of the refractive index distribution of the first liquid crystal layer LC1 when it passes through the first liquid crystal layer LC1.

[0071] Fig. 8 shows a schematic diagram of the phenomenon in which the first polarized component PL1 and the second polarized component PL2 are diffused by the liquid crystal layer. Fig. 8 shows a state in which the first liquid crystal cell 10 and the second liquid crystal cell 20 are stacked, and for simplicity, only the first substrates S11 and S21, the second substrates S12 and S22, the first strip electrodes E11A and E21A, the second strip electrodes E11B and E21B, and the first liquid crystal layer LC1 and the second liquid crystal layer LC2 of each liquid crystal cell are shown. For example, the first transparent adhesive layer TA1 provided between the first liquid crystal cell 10 and the second liquid crystal cell 20 is omitted. It is assumed that the first strip electrodes E11A and the second strip electrodes E11B of the first liquid crystal cell 10 and the first strip electrodes E21A and the second strip electrodes E21B of the second liquid crystal cell 20 are arranged in the same direction. In addition, the alignment direction ALD1 of the alignment film (not shown) on the first substrate S11 of the first liquid crystal cell 10 and the first substrate S21 of the second liquid crystal cell 20 is in the left-right direction of the paper, and the alignment direction ALD2 of the alignment film (not shown) on the second substrate S12 of the first liquid crystal cell 10 and the second substrate S22 of the second liquid crystal cell 20 is in the normal direction to the paper.

[0072] 8, the polarization direction of the first polarization component PL1 is parallel to the initial alignment direction of the liquid crystal molecules on the first substrate S11 side of the first liquid crystal layer LC1 and the initial alignment direction of the liquid crystal molecules on the first substrate S12 side of the second liquid crystal layer LC2 (the direction in which the long axes of the liquid crystal molecules are aligned in the absence of an electric field) of the first liquid crystal cell 10 and the second liquid crystal cell 20. The polarization direction of the second polarization component PL2 is perpendicular to the alignment direction of the liquid crystal molecules on the first substrate S11 side of the first liquid crystal layer LC1 and the first substrate S21 side of the second liquid crystal layer LC2.

[0073] When a voltage is applied to the first strip-shaped electrodes E11A and the second strip-shaped electrodes E11B of the first liquid crystal cell 10, the liquid crystal molecules in the first liquid crystal layer LC1 form regions in which they rise vertically, regions in which they are aligned obliquely along the distribution of the electric field, regions in which their initial alignment state is maintained, etc. Similarly, when a voltage is applied to the first strip-shaped electrodes E21A and the second strip-shaped electrodes E21B of the second liquid crystal cell 20, the liquid crystal molecules in the second liquid crystal layer LC2 form regions in which they rise vertically, regions in which they are aligned obliquely along the distribution of the electric field, regions in which their initial alignment state is maintained, etc.

[0074] The first polarized component PL1 is diffused and rotated by 90 degrees in the first liquid crystal layer LC1, and is not diffused but rotated by 90 degrees in the second liquid crystal layer LC2. The second polarized component PL2 is not diffused but rotated by 90 degrees in the first liquid crystal layer LC1, and is diffused and rotated by 90 degrees in the second liquid crystal layer LC2. That is, the first polarized component PL1 incident on the first substrate S11 is diffused in the first liquid crystal layer LC1 and rotated by the first liquid crystal layer LC1 and the second liquid crystal layer LC2, respectively. The second polarized component PL2 incident on the first substrate S11 is diffused in the second liquid crystal layer LC2 and rotated by the first liquid crystal layer LC1 and the second liquid crystal layer LC2, respectively. Here, the optical rotation refers to a phenomenon in which the polarization axis of a linearly polarized component (for example, the first polarized component PL1 or the second polarized component PL2) rotates along the twisted orientation of the liquid crystal molecules in the process of passing through the liquid crystal layer.

[0075] 8 will be described in more detail. The first electrode E11 and the second electrode E12 of the first liquid crystal cell 10 are perpendicular to each other, and the first electrode E21 and the second electrode E22 of the second liquid crystal cell 20 are perpendicular to each other. The extending direction of the first electrode E11 of the first liquid crystal cell 10 and the extending direction of the first electrode E21 of the second liquid crystal cell 20 are the same. The light including the first polarization component PL1 (polarized component in the X-axis direction) and the second polarization component PL2 (polarized component in the Y-axis direction) is incident on the first substrate S11 of the first liquid crystal cell 10 from a direction perpendicular to the first substrate S11, and is emitted from the second substrate S22 of the second liquid crystal cell 20.

[0076] The liquid crystal molecules of the liquid crystal layer LC1 on the first substrate S11 side of the first liquid crystal cell 10 have their major axes aligned along the X-axis direction, so that when a transverse electric field is generated between the first strip electrode E11A and the second strip electrode E11B, the liquid crystal molecules are aligned in a convex arc shape in the X-axis direction under the action of the electric field, as described with reference to FIG. 7B. The liquid crystal molecules of the first liquid crystal layer LC1 on the second substrate S12 side of the first liquid crystal cell 10 have their major axes aligned along the Y-axis direction, so that when a transverse electric field is generated between the third strip electrode E12A and the fourth strip electrode E12B (not shown), the liquid crystal molecules are aligned in a convex arc shape in the Y-axis direction, as described with reference to FIG. 7C. Due to such an alignment of the liquid crystal molecules, a refractive index distribution depending on the alignment of the liquid crystal molecules is formed on the first substrate S11 side and the second substrate S12 side.

[0077] The first polarized component PL1 parallel to the X-axis that entered the first liquid crystal cell 10 is rotated when passing through the first liquid crystal layer LC1, and becomes a polarized component parallel to the Y-axis on the second substrate S12 side. That is, the first polarized component PL1 has a polarization axis in the X-axis direction on the first substrate S11 side, but the polarization axis gradually changes as it passes through the first liquid crystal layer LC1 in the thickness direction, and the first polarized component PL1 has a polarization axis in the Y-axis direction on the second substrate S12 side, and is emitted from the second substrate S12 side.

[0078] Here, the first polarized component PL1 incident on the first liquid crystal cell 10 from the first substrate S11 side has a polarization axis parallel to the alignment direction of the liquid crystal molecules of the first liquid crystal layer LC1 on the first substrate S11 side, and is diffused in the X-axis direction according to the change in the refractive index distribution of the liquid crystal molecules. In addition, the first polarized component PL1 changes its polarization axis from the X-axis direction to the Y-axis direction by passing through the first liquid crystal layer LC1, and becomes parallel to the alignment direction of the liquid crystal molecules on the second substrate S12 side, and is diffused in the Y-axis direction according to the change in the refractive index distribution of the liquid crystal molecules. In other words, the first polarized component PL1, which is parallel to the X-axis before entering the first liquid crystal cell 10, changes its polarization axis from the X-axis direction to the Y-axis direction while passing through the first liquid crystal cell 10, and is diffused in both the X-axis and Y-axis directions.

[0079] On the other hand, the second polarized component PL2 incident on the first liquid crystal cell 10 from the first substrate S11 side is affected by the first liquid crystal layer LC1 and has its polarization axis changed from the Y-axis direction to the X-axis direction while it is incident on the first substrate S11 and is emitted from the second substrate S12. Here, the second polarized component PL2 is not affected by the refractive index distribution of the liquid crystal molecules on the first substrate S11 side of the first liquid crystal layer LC1 because the polarization axis of the second polarized component PL2 is perpendicular to the alignment direction of the liquid crystal molecules on the first substrate S11 side of the first liquid crystal layer LC1 on the first substrate S11 side, and passes through without being diffused. In addition, the second polarized component PL2 is not affected by the refractive index distribution of the liquid crystal molecules on the second substrate S12 side of the first liquid crystal layer LC1 because the polarization axis of the second polarized component PL2 is changed from the Y-axis direction to the X-axis direction by the first liquid crystal layer LC1, and therefore the polarization axis of the second polarized component PL2 is also perpendicular to the alignment direction of the liquid crystal molecules on the second substrate S12 side of the first liquid crystal layer LC1 on the second substrate S12 side, and passes through without being diffused. That is, the second polarized component PL2 having a polarization axis in the Y-axis direction that enters the first liquid crystal cell 10 changes its polarization axis from the Y-axis direction to the X-axis direction while passing through the first liquid crystal cell 10, but is not diffused by the first liquid crystal layer LC1 and is emitted from the second substrate S12.

[0080] The second liquid crystal layer LC2 of the second liquid crystal cell 20 has a refractive index distribution similar to that of the first liquid crystal layer LC1 of the first liquid crystal cell 10. Therefore, the second liquid crystal cell 20 also experiences the same phenomenon as the first liquid crystal cell 10. Meanwhile, since the polarization axes of the initial first polarized component PL1 and the second polarized component PL2 are switched by passing through the first liquid crystal cell 10, the polarization components affected by the refractive index distribution in the second liquid crystal layer LC2 are also switched. That is, in the process of passing through the second liquid crystal cell 20, the initial first polarized component PL1 changes its polarization axis from the Y axis to the X axis direction again, but does not diffuse. Meanwhile, the initial second polarized component PL2 changes its polarization axis from the X axis to the Y axis direction again, and is diffused by the influence of the refractive index distribution of the second liquid crystal layer LC2.

[0081] As is clear from the above, by stacking two liquid crystal cells having the same structure, the polarization direction of light passing through the two liquid crystal cells is changed twice, and as a result, the polarization direction before and after the light is emitted can be made to remain unchanged. Meanwhile, the two liquid crystal cells can diffuse the light passing through by forming a convex arc-shaped refractive index distribution on the upper and lower sides of the liquid crystal layer by a transverse electric field. Specifically, the first liquid crystal cell 10 can diffuse the light of the first polarization component PL1 in the X-axis direction, the Y-axis direction, or both the X-axis and Y-axis directions, and the second liquid crystal cell 20 can diffuse the light of the second polarization component PL2 in the X-axis direction, the Y-axis direction, or both the X-axis and Y-axis directions. That is, by stacking the first liquid crystal cell 10 and the second liquid crystal cell 20 and forming a refractive index distribution in the liquid crystal layer of each liquid crystal cell, the light can be diffused without changing the polarization state of the light.

[0082] As described above, by stacking two liquid crystal cells having the same structure, the polarization direction of the incident light can be changed twice, and the polarization direction can be made to remain unchanged before and after passing through the two liquid crystal cells. On the other hand, by applying a transverse electric field to the liquid crystal layer to form a refractive index distribution, the light passing through can be refracted in a specific direction. More specifically, the first liquid crystal cell 10 can diffuse the light of the first polarized component PL1 in the X-axis direction, the Y-axis direction, or both the X-axis and Y-axis directions, and the second liquid crystal cell 20 can diffuse the light of the second polarized component PL2 in the X-axis direction, the Y-axis direction, or both the X-axis and Y-axis directions.

[0083] In this way, the first polarized component PL1 of the incident light passing through the first liquid crystal layer LC1 and the second liquid crystal layer LC2 is diffused by the first liquid crystal layer LC1, and the second polarized component PL2 is diffused by the second liquid crystal layer LC2. Moreover, the incident light passing through the first liquid crystal layer LC1 and the second liquid crystal layer LC2 is rotated by 90 degrees by the first liquid crystal layer LC1 and the second liquid crystal layer LC2, respectively. In other words, the incident light including the first polarized component PL1 and the second polarized component PL2 is diffused by the first liquid crystal cell 10, and the second polarized component PL2 is diffused by the second liquid crystal cell 20. That is, by overlapping the first liquid crystal cell 10 and the second liquid crystal cell 20, the scattering of a specific polarized component can be individually controlled, and the light distribution of the light emitted from the light source can be controlled.

[0084] It is known that light refracts at the boundary between different media, and the refraction angle varies depending on the wavelength of the light. When light is incident on a liquid crystal layer in which a refractive index distribution is formed, the refraction angle differs for each wavelength, so color breakup may be visible in the periphery of the light distribution pattern formed by transmitting light through the liquid crystal light control element 102, depending on the type of light source and the distance to the object to be illuminated.

[0085] In contrast, the liquid crystal light control element 102 according to this embodiment suppresses color breakup by overlapping four liquid crystal cells on the light path of the light source and arranging at least two of the four liquid crystal cells rotated 90 degrees with respect to the other liquid crystal cells, as shown in Fig. 3. Specifically, the liquid crystal light control element 102 suppresses color breakup by arranging at least one pair of adjacent overlapping liquid crystal cells so that the longitudinal directions of electrodes having strip-shaped patterns face in different directions. The configuration will be described in detail below based on the electrode configuration and operation of each liquid crystal cell.

[0086] Fig. 9 shows the arrangement of strip electrodes in each liquid crystal cell of the liquid crystal light control element 102, and the manner in which the polarization state and scattering of incident light are controlled by each liquid crystal cell. The arrangement of each electrode in 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 is the same as the structure shown in Fig. 3. Specifically, in the liquid crystal light control element 102 shown in Fig. 9, the alignment direction of liquid crystal molecules in each substrate (S11, S12, S21, S22) of the first liquid crystal cell 10 and the second liquid crystal cell 20 is the same, the longitudinal directions of strip electrodes (E11A, E11B, E21A, E21B) in the first electrodes E11, E21 are the same, and the longitudinal directions of strip electrodes (E12A, E12B, E22A, E22B) in the second electrodes E12, E22 intersecting these electrodes are the same. The alignment directions of the liquid crystal molecules in the substrates (S31, S32, S41, S42) of the third liquid crystal cell 30 and the fourth liquid crystal cell 40 are the same, the longitudinal directions of the strip electrodes (E31A, E31B, E41A, E41B) in the first electrodes E31, E41 are the same, and the longitudinal directions of the strip electrodes (E32A, E32B, E42A, E42B) in the second electrodes E32, E42 that intersect with these electrodes are the same. The longitudinal directions of the strip electrodes (E11A, E11B, E21A, E21B) in the first liquid crystal cell 10 and the second liquid crystal cell 20 intersect at an angle of 90 degrees with the longitudinal directions of the strip electrodes (E31A, E31B, E41A, E41B) in the first electrodes E31, E41 in the third liquid crystal cell 30 and the fourth liquid crystal cell 40.

[0087] In the embodiment shown in FIG. 9, the first liquid crystal cell 10 and the second liquid crystal cell 20 are stacked with their first electrodes E11 and E21 facing the same direction, and the third liquid crystal cell 30 and the fourth liquid crystal cell 40 are stacked with their first electrodes E31 and E41 facing the same direction, but the orientations of the first electrodes E31 and E41 of the third liquid crystal cell 30 and the fourth liquid crystal cell 40 are rotated by 90 degrees with respect to the orientations of the first electrodes E11 and E21 of the first liquid crystal cell 10 and the second liquid crystal cell 20. In addition, the first electrodes (E11, E21, E31, E41) and second electrodes (E12, E22, E32, E42) of each liquid crystal cell extend in directions perpendicular to each other. The same applies to the embodiments shown in FIG. 12 to FIG. 14 described later. It is also possible to adopt a configuration in which the third liquid crystal cell 30 and the fourth liquid crystal cell 40 are stacked in a state rotated within a range of 90 degrees ±10 degrees with respect to the first liquid crystal cell 10 and the second liquid crystal cell 20. It is also possible to adopt a configuration in which the extension directions of the first electrodes (E11, E21, E31, E41) and second electrodes (E12, E22, E32, E42) of each liquid crystal cell are set within a range of 90 degrees ±10 degrees.

[0088] 9, the second electrode E12 of the first liquid crystal cell 10 and the first electrode E41 of the fourth liquid crystal cell 40 are arranged in the same direction, and the second polarized component PL2 can be diffused in the Y-axis direction. The first electrode E11 of the first liquid crystal cell 10 and the second electrode E42 of the fourth liquid crystal cell 40 are arranged in the same direction, and the second polarized component PL2 can be diffused in the X-axis direction. The same applies to the diffusion of the first polarized component PL1, and the second electrode E22 of the second liquid crystal cell 20 and the first electrode E31 of the third liquid crystal cell 30 are arranged in the same direction, and the first polarized component PL1 can be diffused in the Y-axis direction, and the first electrode E21 of the second liquid crystal cell 20 and the second electrode E32 of the third liquid crystal cell 30 are arranged in the same direction, and the first polarized component PL1 can be diffused in the X-axis direction.

[0089] 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 arranged in this order from the light incident side. The light incident on the liquid crystal light control element 102 includes a first polarized component PL1 and a second polarized component PL2 that is orthogonal to the first polarized component PL1.

[0090] In order for the liquid crystal light control element 102 to control the polarization state and scattering state of the incident light, a control signal is input to each liquid crystal cell. FIG. 10A shows an example of the waveform of the control signal applied to the electrode of each liquid crystal cell. Any one of the control signal A, control signal B, and control signal E shown in FIG. 10A is input to each liquid crystal cell. In the control signals A and B, VL1 means a low-level voltage, and VH1 means a high-level voltage. For example, VL1 is a voltage of 0V or -15V, and VH1 is 30V (relative to 0V) or 15V (relative to -15V). The control signals A and B are synchronized, and when the control signal A is at the level of VL1, the control signal B is at the level of VH1, and when the control signal A changes to the level of VH1, the control signal B changes to the level of VL1. The period of the control signals A and B is about 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.

[0091] Below, examples will be shown in which a square light distribution pattern, a cross light distribution pattern, and a line light distribution pattern are formed by the liquid crystal light control element 102 using such control signals.

[0092] (1) Square light distribution pattern The liquid crystal light control device 100 can control the light distribution pattern of the light emitted from the light source unit (106) in various ways by selecting the control signal to be applied to each liquid crystal cell of the liquid crystal light control element 102. Fig. 9 shows, as an example, a case where the light emitted from the light source unit (106) is controlled to have a rectangular light distribution pattern.

[0093] Table 1 shows the control signals applied to each liquid crystal cell in the liquid crystal light control element 102 shown in Fig. 9. Note that control signals A and B shown in Table 1 correspond to the control signals shown in Fig. 10A. [Table 1]

[0094] 9, a control signal A is input to the first strip electrode E11A of the first liquid crystal cell 10, a control signal B is input to the second strip electrode E11B, 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. As shown in Table 1, the control signals A and B are also input to the second liquid crystal cell 20, the third liquid crystal cell 30, and the fourth liquid crystal cell 40, like the first liquid crystal cell 10. That is, in the example shown in FIG. 9, the control signals A and B are alternately applied to all electrodes arranged alternately on each substrate, and an electric field is generated between all of the electrodes.

[0095] In Fig. 9, the alignment direction defined by the alignment film formed on each substrate is perpendicular to the longitudinal direction of the strip electrodes, as indicated by the arrows in the figure. The liquid crystal layer is made of positive type liquid crystal, and in the initial state where 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. In this embodiment, the alignment direction of the alignment film is set at 90 degrees to the extension direction of the strip electrodes, but it can also be set to a direction of 90 degrees ±10 degrees.

[0096] 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 in each liquid crystal cell are affected by the transverse electric field and the alignment state changes as shown in Figs. 7A and 7B. The table inserted in Fig. 9 shows how each polarization component changes when light including the first polarization component PL1 and the second polarization component PL2 passes through each liquid crystal cell. In the following description, the same direction as the first polarization direction is defined as the Y-axis direction, and the same direction as the second polarization direction is defined as the X-axis direction.

[0097] Focusing on the first polarized component PL1 in FIG. 9, the polarization direction of the first polarized component PL1 incident on the first liquid crystal cell 10 is in a direction intersecting (perpendicular to) the long axis direction of the liquid crystal molecules on the first substrate S11 side of the first liquid crystal layer LC1. Therefore, although the liquid crystal molecules on the first substrate S11 side change their refractive index distribution due to the electric field generated by the first electrode E11, the first polarized component PL1 is not diffused and continues to move toward the second substrate S12 side. In addition, the first polarized component PL1 is rotated by 90 degrees in accordance with the twisted orientation of the liquid crystal molecules in the process of moving from the first substrate S11 side to the second substrate S12 side through the first liquid crystal layer LC1. As a result, the first polarized component PL1 transitions to the second polarized component PL2. In addition, the polarization direction of the second polarized component PL2 is in a direction intersecting the long axis direction of the liquid crystal molecules on the second substrate S12 side. Therefore, although the liquid crystal molecules on the second substrate S12 side change their refractive index distribution due to the electric field generated by the second electrode E12, the second polarized component PL2 is not affected and is transmitted as it is. That is, the first polarized component PL1 transitions to the second polarized component PL2 in the process of passing through the first liquid crystal cell 10, but is emitted from the second substrate S12 side without being diffused or the like.

[0098] Then, the second polarized component PL2 enters the second liquid crystal cell 20. The polarization direction of the second polarized component PL2 is parallel to the long axis direction of the liquid crystal molecules on the first substrate S21 side of the second liquid crystal layer LC2. Here, the liquid crystal molecules on the first substrate S21 side have their refractive index distribution changed by the electric field generated by the first electrode E21, so the second polarized component PL2 is diffused in the X-axis direction. In addition, the diffused second polarized component PL2 is rotated by 90 degrees in accordance with the twisted orientation of the liquid crystal molecules in the process of moving from the first substrate S21 side to the second substrate S22 side in the second liquid crystal layer LC2. As a result, the second polarized component PL2 transitions to the first polarized component PL1 again. In addition, the polarization direction of the first polarized component PL1 is parallel to the long axis direction of the liquid crystal molecules on the second substrate S22 side. Here, since the liquid crystal molecules on the second substrate S22 side have their refractive index distribution changed by the electric field generated by the second electrode E22, the first polarized component is further affected by the refractive index distribution of the liquid crystal molecules and diffused in the Y-axis direction, and then emitted. That is, the second polarized component PL2 incident on the second liquid crystal cell 20 is diffused in the X-axis and Y-axis directions while transitioning to the first polarized component PL1 in the process of passing through the second liquid crystal cell 20.

[0099] In this way, of the incident light, the first polarized component PL1 enters the first liquid crystal cell 10 and transitions once to the second polarized component PL2 before being emitted from the second liquid crystal cell 20, and then transitions again to the first polarized component PL1, and is diffused once each in the X-axis direction and the Y-axis direction by the second liquid crystal cell 20.

[0100] In the third liquid crystal cell 30, the longitudinal direction of the first electrode E31 intersects with the first electrode E11 of the first liquid crystal cell 10 and the first electrode E21 of the second liquid crystal cell 20 at an angle of 90 degrees, and the longitudinal direction of the second electrode E32 intersects with the second electrode E12 of the first liquid crystal cell 10 and the second electrode E22 of the second liquid crystal cell 20 at an angle of 90 degrees. Similarly, in the fourth liquid crystal cell 40, the longitudinal direction of the first electrode E41 intersects with the first electrode E11 of the first liquid crystal cell 10 and the first electrode E21 of the second liquid crystal cell 20 at an angle of 90 degrees, and the longitudinal direction of the second electrode E42 intersects with the second electrode E12 of the first liquid crystal cell 10 and the second electrode E22 of the second liquid crystal cell 20 at an angle of 90 degrees. Therefore, in the third liquid crystal cell and the fourth liquid crystal cell, the phenomenon occurring in the first liquid crystal cell 10 and the second liquid crystal cell 20 is reversed for each polarization component. As mentioned above, the intersection angle can be set within the range of 90±10 degrees.

[0101] That is, when the first polarized component PL1, which has passed through the second liquid crystal cell 20 and been diffused once in each of the X-axis direction and the Y-axis direction, enters the third liquid crystal cell 30, the polarization direction of the first polarized component PL1 becomes parallel to the long axis direction of the liquid crystal molecules on the first substrate S31 side of the third liquid crystal layer LC3. Here, the liquid crystal molecules on the first substrate S31 side have their refractive index distribution changed by the electric field generated by the first electrode E31, so the first polarized component PL1 is diffused in the X-axis direction. In addition, the diffused first polarized component PL1 is rotated 90 degrees in accordance with the twisted orientation of the liquid crystal molecules in the process of moving from the first substrate S31 side to the second substrate S32 side in the third liquid crystal layer LC3. As a result, the first polarized component PL1 transitions again to the second polarized component PL2. In addition, the polarization direction of the second polarized component PL2 is parallel to the long axis direction of the liquid crystal molecules on the second substrate S32 side. Here, since the liquid crystal molecules on the second substrate S32 side have their refractive index distribution changed by the electric field generated by the second electrode E32, the second polarized component PL2 is further affected by the refractive index distribution of the liquid crystal molecules and diffused in the Y-axis direction, and then emitted. That is, the first polarized component PL1 incident on the third liquid crystal cell 30 transitions to the second polarized component PL2 in the process of passing through the third liquid crystal cell 30, and diffuses again in the X-axis and Y-axis directions.

[0102] The polarization direction of the second polarized component PL2 emitted from the third liquid crystal cell 30 and incident on the fourth liquid crystal cell 40 is in a direction intersecting with the long axis direction of the liquid crystal molecules on the first substrate S41 side of the fourth liquid crystal layer LC4. Therefore, although the liquid crystal molecules on the first substrate S41 side change their refractive index distribution due to the electric field generated by the first electrode E41, the second polarized component PL2 is not diffused and proceeds directly to the second substrate S42 side. In addition, the second polarized component PL2 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. As a result, the second polarized component PL2 transitions to the first polarized component PL1. In addition, the polarization direction of the first polarized component PL1 is in a direction intersecting with the long axis direction of the liquid crystal molecules on the second substrate S42 side. Therefore, although the liquid crystal molecules on the second substrate S42 side change their refractive index distribution due to the electric field generated by the second electrode E12, the first polarized component PL1 is not affected and passes directly through. That is, the second polarized component PL2 transitions to the first polarized component PL1 while passing through the fourth liquid crystal cell 40, but passes through the fourth liquid crystal cell 40 without being diffused or the like.

[0103] In this way, the first polarized component PL1 entering the third liquid crystal cell 30 transitions once to the second polarized component PL2 and then transitions again to the first polarized component PL1 before exiting the fourth liquid crystal cell 40, and is diffused once each in the X-axis direction and the Y-axis direction by the third liquid crystal cell 30.

[0104] Therefore, the first polarized component PL1 emitted from the light source is diffused twice in the X-axis direction and twice 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.

[0105] In FIG. 9, "transmission" means that the polarized component passes through as is without being diffused or rotated. "Optical rotation" means that the polarized component has its polarization direction shifted by 90 degrees. "Diffusion" means that the polarized component is diffused due to the influence of the refractive index distribution of the liquid crystal molecules. Therefore, in the diagram, for example, "transmission" at the first electrode means that the above-mentioned "transmission" phenomenon occurs in the vicinity of the first electrode of the liquid crystal layer. "Optical rotation" at the liquid crystal layer means that the polarized component has its polarization direction shifted by 90 degrees in the process of moving through the liquid crystal layer from the first substrate side to the second substrate side. The same applies to FIGS. 12 to 14.

[0106] On the other hand, the polarization direction of the second polarized component PL2 is parallel to the long axis direction of the liquid crystal molecules on the first substrate S11 side of the first liquid crystal layer LC1. Therefore, the liquid crystal molecules on the first substrate S11 side have a refractive index distribution due to the electric field generated by the first electrode E11, and the second polarized component PL2 is diffused by this action. Then, the second polarized component PL2 is rotated by 90 degrees according to the twisted orientation of the liquid crystal molecules in the process of moving from the first substrate S11 side to the second substrate S12 side in the first liquid crystal layer LC1. As a result, the second polarized component PL2 transitions to the first polarized component PL1. In addition, the polarization direction of the first polarized component PL1 is parallel to the long axis direction of the liquid crystal molecules on the second substrate S12 side. Since the liquid crystal molecules on the second substrate S12 side have their refractive index distribution changed by the electric field generated by the second electrode E12, the first polarized component PL1 transitioned by the first liquid crystal layer LC1 is diffused in the Y-axis direction by the refractive index distribution formed by the liquid crystal molecules on the second substrate S12 side. That is, the second polarized component PL2 incident on the first liquid crystal cell 10 transitions to the first polarized component PL1 while passing through the first liquid crystal cell 10, and is diffused in the X-axis and Y-axis directions.

[0107] The first polarized component PL1 emitted from the second substrate S12 side of the first liquid crystal cell 10 enters the second liquid crystal cell 20. The polarization direction of the first polarized component PL1 entering the second liquid crystal cell 20 is in a direction intersecting (orthogonal to) the long axis direction of the liquid crystal molecules on the first substrate S21 side of the second liquid crystal layer LC2. Therefore, although the liquid crystal molecules on the first substrate S21 side change their refractive index distribution due to the electric field generated by the first electrode E21, the first polarized component PL1 is not diffused and proceeds directly to the second substrate S22 side. In addition, the first polarized component PL1 is rotated by 90 degrees in accordance with the twisted orientation of the liquid crystal molecules in the process of traveling from the first substrate S21 side to the second substrate S22 side in the second liquid crystal layer LC2. As a result, the first polarized component PL1 transitions to the second polarized component PL2. In addition, the polarization direction of the second polarized component PL2 is in a direction intersecting the long axis direction of the liquid crystal molecules on the second substrate S22 side. Therefore, although the liquid crystal molecules on the second substrate S22 side change their refractive index distribution due to the electric field generated by the second electrode E22, the second polarized component PL2 is not affected and is transmitted as is. That is, the first polarized component PL1 incident on the second liquid crystal cell 20 transitions to the second polarized component PL2 in the process of passing through the second liquid crystal cell 20, but is transmitted without being diffused.

[0108] The second polarized component PL2, which has been rotated by 90 degrees in the first liquid crystal cell 10 and the second liquid crystal cell 20 and diffused once in the X-axis direction and once in the Y-axis direction in the first liquid crystal cell 10, enters the third liquid crystal cell 30. The polarization direction of the second polarized component PL2 entering the third liquid crystal cell 30 is in a direction intersecting (orthogonal to) the long axis direction of the liquid crystal molecules on the first substrate S31 side of the third liquid crystal layer LC3. Therefore, although the liquid crystal molecules on the first substrate S31 side change their refractive index distribution due to the electric field generated by the first electrode E31, the second polarized component PL2 is not diffused and continues to move toward the second substrate S32 side. In addition, the second polarized component PL2 is rotated by 90 degrees in accordance with the twisted orientation of the liquid crystal molecules in the process of moving from the first substrate S31 side to the second substrate S32 side in the third liquid crystal layer LC3. As a result, the second polarized component PL2 transitions to the first polarized component PL1. Furthermore, the polarization direction of the first polarized component PL1 is in a direction intersecting with the long axis direction of the liquid crystal molecules on the second substrate S32 side. Therefore, although the liquid crystal molecules on the second substrate S32 side change their refractive index distribution due to the electric field generated by the second electrode E32, the first polarized component PL1 is not affected and passes through as is. In other words, the second polarized component PL2 that enters the third liquid crystal cell 30 transitions to the first polarized component PL1 in the process of passing through the third liquid crystal cell 30, but passes through without being diffused.

[0109] When the first polarized component PL1, which has passed through the third liquid crystal cell 30, been diffused once in the X-axis direction and once in the Y-axis direction, and has been rotated 90 degrees by the first liquid crystal cell 10, the second liquid crystal cell 20, and the third liquid crystal cell 30, enters the fourth liquid crystal cell 40, the polarization direction of the first polarized component PL1 is parallel to the long axis direction of the liquid crystal molecules on the first substrate S41 side of the fourth liquid crystal cell LC4. Since the refractive index distribution of the liquid crystal molecules on the first substrate S41 side of the fourth liquid crystal cell 40 is changed by the electric field generated by the first electrode E41, the first polarized component PL1 is diffused in the X-axis direction. In addition, the diffused first polarized component PL1 is rotated 90 degrees in accordance with the twisted orientation of the liquid crystal molecules in the process of moving from the first substrate S41 side to the second substrate S42 side in the fourth liquid crystal layer LC4. As a result, the first polarized component PL1 transitions again to the second polarized component PL2. The polarization direction of the second polarized component PL2 is parallel to the long axis direction of the liquid crystal molecules on the second substrate S42 side. Here, since the liquid crystal molecules on the second substrate S42 have their refractive index distribution changed by the electric field generated by the second electrode E42, this second polarization component PL2 is further influenced by the refractive index distribution of the liquid crystal molecules and diffused in the Y-axis direction before being emitted from the second substrate S42 side.

[0110] In this way, the second polarized component PL2 entering the third liquid crystal cell 30 transitions once to the first polarized component PL1 and then transitions again to the second polarized component PL2 before being emitted from the fourth liquid crystal cell 40, and is diffused once each in the X-axis direction and the Y-axis direction by the fourth liquid crystal cell 40.

[0111] Therefore, the second polarized component PL2 emitted from the light source is diffused twice in the X-axis direction and twice 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.

[0112] 9 indicates that the polarized light component is diffused once in the X-axis direction before reaching the position, and (diffused light 1X1Y) indicates that the polarized light component is diffused once in the X-axis direction and once in the Y-axis direction before reaching the position.

[0113] Fig. 11A and Fig. 11B are graphs showing the angle dependence of chromaticity of a liquid crystal light control element. Fig. 11A shows the angle dependence of the x coordinate value of the chromaticity coordinates, and Fig. 11B shows the angle dependence of the y coordinate value. Fig. 11A and Fig. 11B show the angle dependence of chromaticity of an element (A) in which four liquid crystal cells are used and the third and fourth liquid crystal cells are rotated 90 degrees, like the liquid crystal light control element 102 according to this embodiment. Each graph also shows the characteristics of an element (B) composed of two liquid crystal cells as a reference example.

[0114] 11A and 11B, in the reference example, the characteristics of the element (B) having two liquid crystal cells, the x-coordinate and y-coordinate values ​​change significantly with the change in angle, and it is clear that the angle dependency of the chromaticity is significantly manifested. In contrast, the element (A) having four liquid crystal cells and in which the third and fourth liquid crystal cells are rotated by 90 degrees as in the liquid crystal light control element 102 of this embodiment, shows that the angle dependency of the chromaticity is further improved. In other words, the configuration of the liquid crystal light control element 102 of this embodiment makes it possible to suppress color breakup.

[0115] In this way, a single polarized component is diffused in the same direction at least twice by an electrode disposed in a different liquid crystal cell on the light incident side with a liquid crystal layer in between and an electrode disposed on the opposite side from the light incident side, thereby preventing color breaking up.

[0116] Based on this viewpoint, when forming a rectangular light distribution pattern, it is not necessary to input control signals of the same voltage level to the electrodes of all liquid crystal cells, and it is also possible to use different control signals for each pair, such as the pair of the second electrode E12 of the first liquid crystal cell 10 and the first electrode E41 of the fourth liquid crystal cell 40, which diffuses the second polarization component PL2 in the Y-axis direction; the pair of the first electrode E11 of the first liquid crystal cell 10 and the second electrode E42 of the fourth liquid crystal cell 40, which diffuses the second polarization component PL2 in the X-axis direction; the pair of the second electrode E22 of the second liquid crystal cell 20 and the first electrode E31 of the third liquid crystal cell 30, which diffuses the first polarization component PL1 in the Y-axis direction; and the pair of the first electrode E21 of the second liquid crystal cell 20 and the second electrode E32 of the third liquid crystal cell 30, which diffuses the first polarization component PL1 in the X-axis direction.

[0117] Table 2 shows an example of a case where the voltage level of the control signal is the same for each group, and control signals of different voltage levels are input to the first electrode and the second electrode of one liquid crystal cell. Note that the control signals A, B, C, D, and E in Table 2 correspond to the control signals shown in FIG. 10B. Note that in FIG. 10B, the voltage levels of the control signals A, B, C, D, and E have the relationship VH1>VH2>VE>VL2>VL1. For example, when VL1=-15V and VH1=15V, the voltages VL2=-12V and VH2=12V can be set. [Table 2]

[0118] According to the combination of control signals shown in Table 2, the amount of each polarization component diffused in the Y-axis direction and the X-axis direction can be varied, so that the rectangular light distribution pattern can be varied. For example, by adjusting the voltage levels of the control signals A, B, C, and D, a square light distribution pattern or a rectangular light distribution pattern can be formed.

[0119] When control signals of the same pattern as shown in Table 1 are applied to each liquid crystal cell of the liquid crystal light control element 102 having such an arrangement of liquid crystal cells, the first polarized component PL1 and the second polarized component PL2 are diffused evenly in the X-axis direction and the Y-axis direction as described above, so that a rectangular light distribution pattern can be formed. Also, as described later, color breakup in the light distribution pattern can be prevented.

[0120] (2) Cross light distribution pattern 12 shows an example in which light emitted from a light source unit 106 is controlled to have a cross-shaped light distribution pattern. The arrangement of the liquid crystal cells of the liquid crystal light control element 102 shown in FIG.

[0121] Table 3 shows the control signals applied to each liquid crystal cell in the liquid crystal light control element 102 shown in Fig. 12. Note that the control signals A, B, and C shown in Table 3 correspond to the control signals shown in Fig. 10A. [Table 3]

[0122] As shown in Table 3, when forming a cross-shaped light distribution pattern, a control signal for generating a transverse electric field is input to the first electrode E11 of the first liquid crystal cell 10, the second electrode E22 of the second liquid crystal cell 20, the first electrode E31 of the third liquid crystal cell 30, and the second electrode E42 of the fourth liquid crystal cell 40, and a control signal E of a constant voltage is input to the second electrode E12 of the first liquid crystal cell 10, the first electrode E21 of the second liquid crystal cell 20, the second electrode E32 of the third liquid crystal cell 30, and the first electrode E41 of the fourth liquid crystal cell 40 to control the state in which no transverse electric field is generated. Note that "transmission", "diffusion", and "optical rotation" in the table basically correspond to "transmission", "diffusion", and "optical rotation" mentioned in the explanation of FIG. 9. In addition, in the driving of FIG. 12, there is a configuration in which the same potential is applied to electrodes located on the same substrate, but in the state in which the same potential is applied, no potential is generated between the electrodes and no electric field is generated in the liquid crystal layer. Therefore, the liquid crystal molecules located on the substrate side do not change their orientation state from the initial orientation. Therefore, the polarized light component passing through the liquid crystal layer in this electroless state passes through without being diffused. This case is also included in the "transmission" category.

[0123] In Fig. 12, first, attention is paid to the first polarized component PL1. The polarization direction of the first polarized component PL1 incident on the first liquid crystal cell 10 is in a direction intersecting with the long axis direction of the liquid crystal molecules on the first substrate S11 side of the first liquid crystal layer LC1, and the first electrode E11 on the first substrate S11 side forms an electric field (electrodes forming an electric field are shown by hatching in Fig. 12. The same applies to Figs. 13 and 14 below). Under such conditions, the first polarized component PL1 passes through the first liquid crystal layer LC1 on the first substrate S11 side without being diffused. In addition, the first polarized component PL1 is rotated by 90 degrees while passing through the first liquid crystal layer LC1, and transitions to the second polarized component PL2. Moreover, the polarization direction of the second polarized component PL2 is in a direction intersecting the long axis direction of the liquid crystal molecules on the second substrate S12 side, and the second electrode E12 on the second substrate S12 side does not generate an electric field (electrodes that do not generate an electric field are shown as white in FIG. 12. The same applies to FIGS. 13 and 14 below.) Under these conditions, the second polarized component PL2 passes through the first liquid crystal layer LC1 on the second substrate S12 side without diffusing, and is emitted to the second liquid crystal cell 20.

[0124] The polarization direction of the second polarized component PL2 incident on the second liquid crystal cell 20 is parallel to the long axis direction of the liquid crystal molecules on the first substrate S21 side of the second liquid crystal layer LC2, and the first electrode E21 on the first substrate S21 side does not form an electric field. Under such conditions, the second polarized component PL2 passes through the second liquid crystal layer LC2 on the first substrate S21 side without being diffused. In addition, the second polarized component PL2 is rotated by 90 degrees while passing through the second liquid crystal layer LC2, and transitions to the first polarized component PL1 again. In addition, the polarization direction of the first polarized component PL1 is parallel to the long axis direction of the liquid crystal molecules on the second substrate S22 side, and the second electrode E22 on the second substrate S22 side forms an electric field. Under such conditions, the first polarized component PL1 diffuses in the Y-axis direction and is then emitted to the third liquid crystal cell 30.

[0125] The polarization direction of the first polarized component PL1 incident on the third liquid crystal cell 30 is parallel to the long axis direction of the liquid crystal molecules on the first substrate S31 side of the third liquid crystal layer LC3, and the first electrode E31 on the first substrate S31 side forms an electric field. Under such conditions, the first polarized component PL1 is diffused in the Y-axis direction and moves toward the second substrate S32 side. In addition, the first polarized component PL1 is rotated by 90 degrees while passing through the third liquid crystal layer LC3, and transitions again to the second polarized component PL2. In addition, the polarization direction of the second polarized component PL2 is parallel to the long axis direction of the liquid crystal molecules on the second substrate S32 side, and the second electrode E32 on the second substrate S32 side does not form an electric field. Under such conditions, the second polarized component PL2 is transmitted through the third liquid crystal layer LC3 on the second substrate S32 side without being diffused, and is output to the fourth liquid crystal cell 40.

[0126] The polarization direction of the second polarized component PL2 incident on the fourth liquid crystal cell 40 is in a direction intersecting with the long axis direction of the liquid crystal molecules on the first substrate S41 side of the fourth liquid crystal layer LC4, and the first electrode E41 on the first substrate S41 side does not form an electric field. Under such conditions, the second polarized component PL2 passes through the fourth liquid crystal layer LC4 on the first substrate S41 side without being diffused. In addition, the second polarized component PL2 is rotated by 90 degrees while passing through the fourth liquid crystal layer LC4, and transitions to the first polarized component PL1 again. In addition, the polarization direction of the first polarized component PL1 is in a direction intersecting with the long axis direction of the liquid crystal molecules on the second substrate S42 side, and the second electrode E42 on the second substrate S42 side forms an electric field. Under such conditions, the first polarized component PL1 is emitted from the fourth liquid crystal cell 40 without being diffused.

[0127] In this way, when the liquid crystal light control element 102 shown in Figure 12 is driven with the potential shown in Table 3, the first polarization component PL1 of the light emitted from the light source is rotated four times in the process of passing from the first liquid crystal cell 10 to the fourth liquid crystal cell 40, and is diffused twice in the Y-axis direction.

[0128] Next, in FIG. 12, attention is focused on the second polarized component PL2. The polarization direction of the second polarized component PL2 incident on the first liquid crystal cell 10 is parallel to the long axis direction of the liquid crystal molecules on the first substrate S11 side of the first liquid crystal layer LC1, and the first electrode E11 on the first substrate S11 side forms an electric field. Under such conditions, the second polarized component PL2 is diffused in the X-axis direction and passes through the first liquid crystal layer LC1 on the first substrate side. In addition, the second polarized component PL2 is rotated by 90 degrees while passing through the first liquid crystal layer LC1, and transitions to the first polarized component PL1. In addition, the polarization direction of the first polarized component PL1 is parallel to the long axis direction of the liquid crystal molecules on the second substrate S12 side, and the second electrode E12 on the second substrate S12 side does not form an electric field. Under such conditions, the first polarized component PL1 is transmitted through the first liquid crystal layer PC1 on the second substrate S12 side without being diffused, and is output to the second liquid crystal cell 20.

[0129] The polarization direction of the first polarized component PL1 incident on the second liquid crystal cell 20 is in a direction intersecting the long axis direction of the liquid crystal molecules on the first substrate S21 side of the second liquid crystal layer LC2, and the first electrode E21 on the first substrate S21 side does not form an electric field. Under such conditions, the first polarized component PL1 passes through the second liquid crystal layer LC2 on the first substrate S21 side without being diffused. In addition, the first polarized component PL1 is rotated by 90 degrees while passing through the second liquid crystal layer LC2, and becomes the second polarized component PL2 again. In addition, the polarization direction of the second polarized component PL2 is in a direction parallel to the long axis direction of the liquid crystal molecules on the second substrate S22 side of the second liquid crystal layer LC2, and the second electrode E22 on the second substrate S22 side forms an electric field. Under such conditions, the second polarized component diffuses in the X-axis direction and is then output to the third liquid crystal cell 30.

[0130] The polarization direction of the second polarized component PL2 incident on the third liquid crystal cell 30 is in a direction intersecting the long axis direction of the liquid crystal molecules on the first substrate S31 side of the third liquid crystal layer LC3, and the first electrode E31 on the first substrate S31 side forms an electric field. Under such conditions, the second polarized component PL2 passes through the third liquid crystal layer LC3 on the first substrate side without being diffused. In addition, the second polarized component PL2 is rotated by 90 degrees while passing through the third liquid crystal layer LC3, and becomes the first polarized component PL1 again. In addition, the polarization direction of the first polarized component PL1 is in a direction intersecting the long axis direction of the liquid crystal molecules on the second substrate S32 side, and the second electrode E32 on the second substrate S32 side does not form an electric field. Under such conditions, the first polarized component PL1 passes through the third liquid crystal layer LC3 on the second substrate S32 side without being diffused, and is output to the fourth liquid crystal cell 40.

[0131] The polarization direction of the first polarized component PL1 incident on the fourth liquid crystal cell 40 is parallel to the long axis direction of the liquid crystal molecules on the first substrate S41 side of the fourth liquid crystal layer LC4, and the first electrode E41 on the first substrate S41 side does not form an electric field. Under such conditions, the first polarized component PL1 passes through the fourth liquid crystal layer LC4 on the first substrate S41 side without being diffused. In addition, the first polarized component PL1 is rotated by 90 degrees while passing through the fourth liquid crystal layer LC4, and becomes the second polarized component PL2 again. In addition, the polarization direction of the second polarized component PL2 is parallel to the long axis direction of the liquid crystal molecules on the second substrate S42 side, and the second electrode E42 on the second substrate S42 side forms an electric field. Under such conditions, the second polarized component PL2 diffuses in the X-axis direction and is then emitted from the fourth liquid crystal cell 40.

[0132] In this way, when the liquid crystal light control element 102 shown in FIG. 12 is driven with the potentials shown in Table 3, the second polarization component PL2 of the light emitted from the light source is rotated four times as it passes from the first liquid crystal cell 10 to the fourth liquid crystal cell 40, and is diffused twice in the X-axis direction.

[0133] 12 and Table 3, the light emitted from the light source unit 106 passes through the liquid crystal light control element 102, whereby the first polarization component PL1 is diffused twice in the Y-axis direction and the second polarization component PL2 is diffused twice in the X-axis direction. This makes it possible to shape the light emitted from the light source unit 106 into a cross-shaped light distribution pattern. Furthermore, as will be described later, color breakup can also be prevented in this light distribution pattern.

[0134] Similarly to the example of the rectangular light distribution, a cross-shaped light distribution pattern can be formed by applying the control signals shown in Table 4 to a pair of the second electrode E12 of the first liquid crystal cell 10 and the first electrode E41 of the fourth liquid crystal cell 40 that diffuses the second polarized component PL2 in the Y-axis direction, a pair of the first electrode E11 of the first liquid crystal cell 10 and the second electrode E42 of the fourth liquid crystal cell 40 that diffuses the second polarized component PL2 in the X-axis direction, a pair of the second electrode E22 of the second liquid crystal cell 20 and the first electrode E31 of the third liquid crystal cell 30 that diffuses the first polarized component PL1 in the Y-axis direction, and a pair of the first electrode E21 of the second liquid crystal cell 20 and the second electrode E32 of the third liquid crystal cell 30 that diffuses the first polarized component PL1 in the X-axis direction. The control signals shown in Table 4 correspond to FIG. 10B. [Table 4]

[0135] (3) Line light distribution pattern (X-axis direction) 13 shows an example in which light emitted from a light source unit 106 is controlled to have a linear (X-axis direction) light distribution pattern. The arrangement of the liquid crystal cells of the liquid crystal light control element 102 shown in FIG.

[0136] Table 5 shows the control signals applied to each liquid crystal cell in the liquid crystal light control element 102 shown in Fig. 13. Note that the control signals A, B, and C shown in Table 5 correspond to the control signals shown in Fig. 10A. [Table 5]

[0137] As shown in Table 5, when forming a line-shaped light distribution pattern extending in the X-axis direction, a control signal for generating a transverse electric field is input to the first electrode E11 of the first liquid crystal cell 10, the first electrode E21 of the second liquid crystal cell 20, the second electrode E32 of the third liquid crystal cell 30, and the second electrode E42 of the fourth liquid crystal cell 40, and a control signal E of a constant voltage is input to the second electrode E12 of the first liquid crystal cell 10, the first electrode E21 of the second liquid crystal cell 20, the first electrode E31 of the third liquid crystal cell 30, and the first electrode E41 of the fourth liquid crystal cell 40 to control them to a state in which no transverse electric field is generated.

[0138] Focusing on the first polarized component PL1 in Figure 13, the polarization direction of the first polarized component PL1 entering the first liquid crystal cell 10 is in a direction that intersects (is perpendicular to) the long axis direction of the liquid crystal molecules in the first liquid crystal layer LC1, so it enters as is without being scattered, and is rotated by 90 degrees in the first liquid crystal layer LC1 to become the second polarized component PL2.

[0139] The second polarized component PL2 incident on the second liquid crystal cell 20 is diffused in the X-axis direction by the liquid crystal molecules affected by the electric field of the first electrode E21, rotated in the second liquid crystal layer LC2 to become the first polarized component PL1(1X), and passes through the second liquid crystal cell 20. The first polarized component PL1(1X) incident on the third liquid crystal cell 30 is rotated in the third liquid crystal layer LC3 to become the second polarized component PL2(1X), and is further diffused in the X-axis direction by the liquid crystal molecules affected by the electric field of the second electrode E32, and becomes the second polarized component PL2(2X) after passing through the third liquid crystal cell 30. The second polarized component PL2(2X) incident on the fourth liquid crystal cell 40 is rotated in the fourth liquid crystal layer LC4 to become the first polarized component PL1(2X), and is emitted from the fourth liquid crystal cell 40.

[0140] On the other hand, the second polarized component PL2 is diffused in the X-axis direction by liquid crystal molecules subjected to the action of the electric field of the first electrode E11 of the first liquid crystal cell 10, rotated in the first liquid crystal layer LC1 to become the first polarized component PL1(1X), and enters the second liquid crystal cell 20. The first polarized component PL1(1X) diffused once in the X-axis direction is rotated in the second liquid crystal layer LC2 of the second liquid crystal cell 20 to become the second polarized component PL2(1X), and enters the third liquid crystal cell 30. This second polarized component PL2(1X) is rotated in the third liquid crystal layer LC3 of the third liquid crystal cell 30, and enters the fourth liquid crystal cell 40 as the first polarized component PL1(1X). The first polarized component PL1(1X) is rotated in the fourth liquid crystal layer LC4, and is diffused again in the X-axis direction by liquid crystal molecules subjected to the action of the electric field of the second electrode E42, and is emitted from the fourth liquid crystal cell 40 as the second polarized component PL2(2X).

[0141] Similarly to the example of rectangular light distribution, a linear light distribution pattern extending in the X-axis direction can be formed by applying the control signals shown in Table 6 to a pair of the first electrode E11 of the first liquid crystal cell 10 and the second electrode E42 of the fourth liquid crystal cell 40 that diffuse the second polarization component PL2 in the X-axis direction, and a pair of the first electrode E21 of the second liquid crystal cell 20 and the second electrode E32 of the third liquid crystal cell 30 that diffuse the first polarization component PL1 in the X-axis direction. The control signals shown in Table 6 correspond to FIG. 10B. [Table 6]

[0142] 13 and Tables 5 and 6, the light emitted from the light source unit 106 passes through the liquid crystal light control element 102, whereby the first polarization component PL1 is diffused twice in the X-axis direction, and the second polarization component PL2 is diffused twice in the X-axis direction. This makes it possible to shape the light emitted from the light source unit 106 into a linear light distribution pattern extending in the X-axis direction. Furthermore, as will be described later, color breakup can also be prevented in this light distribution pattern.

[0143] (4) Line light distribution pattern (Y-axis direction) 14 shows an example in which light emitted from a light source unit 106 is controlled to have a linear (Y-axis direction) light distribution pattern. The arrangement of the liquid crystal cells of the liquid crystal light control element 102 shown in FIG.

[0144] Table 7 shows the control signals applied to each liquid crystal cell in the liquid crystal light control element 102 shown in Fig. 14. Note that the control signals A, B, and E shown in Table 7 correspond to the control signals shown in Fig. 10A. [Table 7]

[0145] As shown in Table 7, when forming a line-shaped light distribution pattern extending in the Y-axis direction, a control signal E of a constant voltage is input to the first electrode E11 of the first liquid crystal cell 10, the first electrode E21 of the second liquid crystal cell 20, the second electrode E32 of the third liquid crystal cell 30, and the second electrode E42 of the fourth liquid crystal cell 40 to perform control so that a transverse electric field is not generated, and control signals A and B which generate a transverse electric field are input to the second electrode E12 of the first liquid crystal cell 10, the first electrode E22 of the second liquid crystal cell 20, the first electrode E31 of the third liquid crystal cell 30, and the first electrode E41 of the fourth liquid crystal cell 40.

[0146] Focusing on the first polarized component PL1 in Figure 14, the polarization direction of the first polarized component PL1 entering the first liquid crystal cell 10 is in a direction that intersects (is perpendicular to) the long axis direction of the liquid crystal molecules in the first liquid crystal layer LC1, so it enters as is without being scattered, and is rotated by 90 degrees in the first liquid crystal layer LC1 to become the second polarized component PL2.

[0147] The second polarized component PL2 incident on the second liquid crystal cell 20 is rotated by the second liquid crystal layer LC2 and diffused in the Y-axis direction by liquid crystal molecules affected by the electric field of the second electrode E22 to become the first polarized component PL1(1Y). The first polarized component PL1(1Y) incident on the third liquid crystal cell 30 is diffused in the Y-axis direction by liquid crystal molecules affected by the electric field of the first electrode E31 and is rotated by the third liquid crystal layer LC3 to become the second polarized component PL2(2Y). The second polarized component PL2(2Y) incident on the fourth liquid crystal cell 40 is rotated by the fourth liquid crystal layer LC4 to become the first polarized component PL1(2Y) and is emitted from the fourth liquid crystal cell 40.

[0148] On the other hand, the second polarized component PL2 is rotated in the first liquid crystal layer LC1 and diffused in the Y-axis direction by the liquid crystal molecules affected by the electric field of the second electrode E12 to become the first polarized component PL1(1Y). The first polarized component PL1(1Y) incident on the second liquid crystal cell 20 is rotated in the second liquid crystal layer LC2 to become the second polarized component PL2(1Y). The second polarized component PL2(1Y) incident on the third liquid crystal cell 30 is rotated in the third liquid crystal layer LC3 to become the first polarized component PL1(1Y) and incident on the fourth liquid crystal cell 40. The first polarized component PL1(1Y) is diffused in the Y-axis direction by the liquid crystal molecules affected by the electric field of the first electrode E41, and is rotated in the fourth liquid crystal layer LC4 to be emitted as the second polarized component LC2(2Y).

[0149] Similarly to the example of rectangular light distribution, a line-shaped light distribution pattern extending in the Y-axis direction can be formed by applying the control signals shown in Table 8 to a pair of the second electrode E12 of the first liquid crystal cell 10 and the first electrode E41 of the fourth liquid crystal cell 40 that diffuse the second polarization component PL2 in the Y-axis direction, and a pair of the second electrode E22 of the second liquid crystal cell 20 and the first electrode E31 of the third liquid crystal cell 30 that diffuse the first polarization component PL1 in the Y-axis direction. The control signals shown in Table 8 correspond to FIG. 10B. [Table 8]

[0150] 14 and Tables 7 and 8, the light emitted from the light source unit 106 passes through the liquid crystal light control element 102, whereby the first polarization component PL1 is diffused twice in the Y-axis direction, and the second polarization component PL2 is diffused twice in the Y-axis direction. This makes it possible to shape the light emitted from the light source unit 106 into a linear light distribution pattern extending in the Y-axis direction. Furthermore, as will be described later, color breakup can also be prevented in this light distribution pattern.

[0151] The liquid crystal light control element 102 according to this embodiment includes a plurality of liquid crystal cells, and has a structure in which at least one liquid crystal cell and another liquid crystal cell adjacent to (overlapping) the at least one liquid crystal cell are rotated by 90 degrees and stacked, thereby preventing color breakup in the light distribution pattern. The effect of rotating the liquid crystal cell by 90 degrees in this way is considered to be due to the asymmetry of the liquid crystal, such as the pretilt direction. Therefore, each liquid crystal cell may be arranged so as to break the asymmetry of the liquid crystal. More specifically, as shown in FIG. 14, the alignment direction of the first liquid crystal cell 10 on the first substrate S11 side faces the +x direction, while the alignment direction of the fourth liquid crystal cell 40 on the second substrate S42 side faces the -x direction. In addition, other combinations, such as a structure in which the alignment direction of the first liquid crystal cell 10 on the second substrate S12 side and the alignment direction of the fourth liquid crystal cell 40 on the first substrate S41 side face each other while being in the y direction, may also be adopted. Similarly, it is also possible to adopt a configuration in which the alignment direction of the first substrate S21 side of the second liquid crystal cell 20 and the alignment direction of the second substrate S32 side of the third liquid crystal cell 30 are aligned in the x direction and faced each other, and also in which the alignment direction of the second substrate S22 side of the second liquid crystal cell 20 and the alignment direction of the first substrate S31 side of the third liquid crystal cell 30 are aligned in the y direction and faced each other.

[0152] 15A and 15B, 16A and 16B show examples of the arrangement of liquid crystal cells of the liquid crystal light control element 102. Fig. 15A shows an example in which the first liquid crystal cell 10 and the second liquid crystal cell 20 are grouped together, and the third liquid crystal cell 30 and the fourth liquid crystal cell 40 are grouped together, with one group being taken as the reference and the other group being rotated 90 degrees. This arrangement corresponds to the arrangement in Figs. 2 and 3.

[0153] Fig. 15B shows a structure in which, of the four liquid crystal cells, the odd-numbered liquid crystal cells are rotated 90 degrees relative to the even-numbered liquid crystal cells. In other words, Fig. 15B shows a structure in which the even-numbered liquid crystal cells are rotated 90 degrees relative to the odd-numbered liquid crystal cells.

[0154] Fig. 16A shows a combination in which 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 each rotated by 90 degrees. Fig. 16B shows a combination in which the first liquid crystal cell 10 and the third liquid crystal cell 30 are turned upside down.

[0155] In addition, in Figures 15A and 15B and Figures 16A and 16B, the first electrodes E11, E21, E31, and E41 are electrodes formed on the first substrate S11 (lower side), and the second electrodes E12, E22, E32, and E42 are electrodes formed on the second substrate S12 (upper side). As described with reference to Figure 3, the first electrode E11 includes a first strip electrode (E11A) and a second strip electrode (E11B), and the second electrode E12 includes a third strip electrode (E12A) and a fourth strip electrode (E12B). The same applies to the first electrodes E21, E31, and E41 and the second electrodes E22, E32, and E42. In addition, in Figures 15A and 15B and Figures 16A and 16B, the direction of the arrow indicates the longitudinal direction of the strip electrodes.

[0156] 15A, the longitudinal direction of the stripe patterns of the first electrode E11 of the first liquid crystal cell 10 and the first electrode E21 of the second liquid crystal cell 20 is arranged in a direction parallel to the Y-axis direction shown in the figure, the longitudinal direction of the stripe patterns of the second electrode E12 of the first liquid crystal cell 10 and the second electrode E22 of the second liquid crystal cell 20 is arranged in a direction parallel to the X-axis direction, the longitudinal direction of the stripe patterns of the first electrode E31 of the third liquid crystal cell 30 and the first electrode E41 of the fourth liquid crystal cell 40 is arranged in a direction parallel to the X-axis direction, and the longitudinal direction of the stripe patterns of the second electrode E32 of the third liquid crystal cell 30 and the second electrode E42 of the fourth liquid crystal cell 40 is arranged in a direction parallel to the Y-axis direction. With such a combination of electrode arrangements of the liquid crystal cells, the diffusion direction of the polarized light component can be controlled at least twice by different liquid crystal cells, and color breakup of the distributed illumination light can be prevented.

[0157] 15B, 16A, and 16B, the longitudinal direction of the stripe patterns of the first electrode E11 of the first liquid crystal cell 10 and the first electrode E31 of the third liquid crystal cell 30 is arranged in a direction parallel to the Y-axis direction, the longitudinal direction of the stripe patterns of the second electrode E12 of the first liquid crystal cell 10 and the second electrode E32 of the third liquid crystal cell 30 is arranged in a direction parallel to the X-axis direction, the longitudinal direction of the stripe patterns of the first electrode E21 of the second liquid crystal cell 20 and the first electrode E41 of the fourth liquid crystal cell 40 is arranged in a direction parallel to the X-axis direction, and the longitudinal direction of the stripe patterns of the second electrode E22 of the second liquid crystal cell 20 and the second electrode E42 of the fourth liquid crystal cell 40 is arranged in a direction parallel to the Y-axis direction. With such a combination of electrode arrangements of the liquid crystal cells, the diffusion direction of the polarized light component can be controlled at least twice by different liquid crystal cells, and color breakup of the distributed illumination light can be prevented.

[0158] As described in this embodiment, in the liquid crystal light control element 102 in which multiple liquid crystal cells are stacked, the diffusion of the same polarized component among the polarized components of the incident light is controlled by electrodes at different positions of different liquid crystal cells (for example, the second electrode E12 of the first liquid crystal cell 10 and the first electrode E11 of the fourth liquid crystal cell 40), thereby making it possible to prevent color breakup from occurring in the light distribution pattern.

[0159] As described above, according to this embodiment, in a liquid crystal light control device that controls the distribution of illumination light by utilizing the electro-optical effect of liquid crystal, it is possible to suppress color breakup in a light distribution pattern formed into a predetermined shape.

[0160] The present invention is not limited to the embodiments disclosed in this specification, and the components can be modified and embodied without departing from the scope of the present invention. In addition, various inventions can be formed by appropriately combining multiple components disclosed in the embodiments of this specification. For example, some components may be deleted from all the components shown in the embodiments. Furthermore, components across different embodiments may be appropriately combined. [Explanation of symbols]

[0161] 10: first liquid crystal cell, 20: second liquid crystal cell, 30: third liquid crystal cell, 40: fourth liquid crystal cell, 100: liquid crystal light control device, 102: liquid crystal light control element, 104: circuit board, 106: light source unit, S11, S21, S31, S41: first substrate, S12, S22, S32, S42: second substrate, F1: first flexible wiring board, F2: second flexible wiring board, F3: third flexible wiring board, F4: fourth flexible wiring board, TA1: first transparent adhesive layer, TA2: second transparent adhesive layer, TA3: third transparent adhesive layer, LC1: first liquid crystal layer, LC2: second liquid crystal layer, LC3: third liquid crystal layer, LC4: fourth liquid crystal layer, E11, E21, E31, E41: first electrode, E11A, E21A, E31A, E41A: first Strip electrode, E11B, E21B, E31B, E41B: Second strip electrode, E12, E22, E32, E42: Second electrode, E12A, E22A, E32A, E42A: Third strip shaped electrode, E12B, E22B, E32B, E42B: 4th strip electrode, PL11: 1st feed line, PL12: 2nd feed line, PL13: 3rd feed line, PL14: 4th feed line, PL 15: fifth power supply line, PL16: sixth power supply line, T11: first connection terminal, T12: second connection terminal, T13: third connection terminal, T14: fourth connection terminal, PT11: first power supply terminal, PT12: second power supply terminal, PT13: third power supply terminal, PT14: fourth power supply terminal, AL11: first alignment film, AL12: second alignment film, SE: sealing material, CP11: first conductive member

Claims

1. A first liquid crystal cell; A second liquid crystal cell; A third liquid crystal cell; a fourth liquid crystal cell; Each of the first liquid crystal cell, the second liquid crystal cell, the third liquid crystal cell, and the fourth liquid crystal cell is A first substrate provided with a first electrode including a strip-shaped pattern; a second substrate provided with a second electrode having a strip-shaped pattern; A first alignment film provided on the first substrate; a second alignment film provided on the second substrate; a liquid crystal layer between the first substrate and the second substrate; the first electrode includes at least one first strip electrode having the strip pattern and at least one second strip electrode having the strip pattern, the at least one first strip electrode and the at least one second strip electrode being spaced apart and alternately arranged; the second electrode includes at least one third strip-shaped electrode having the strip-shaped pattern and at least one fourth strip-shaped electrode having the strip-shaped pattern, the at least one third strip-shaped electrode and the at least one fourth strip-shaped electrode being spaced apart and alternately arranged; the first substrate and the second substrate are arranged so that longitudinal directions of the strip-shaped patterns of the first electrodes and the second electrodes intersect with each other; an alignment direction of the first alignment film intersects with a longitudinal direction of the strip-shaped pattern of the first electrode; an alignment direction of the second alignment film intersects with a longitudinal direction of the strip-shaped pattern of the second electrode; The first to fourth liquid crystal cells are arranged such that the first liquid crystal cell, the second liquid crystal cell, the third liquid crystal cell, and the fourth liquid crystal cell are overlapped in this order from the light incident side, and the remaining liquid crystal cells are stacked in a state rotated 90 degrees with respect to two liquid crystal cells. A liquid crystal light control device.

2. 2. The liquid crystal display device according to claim 1, wherein the third liquid crystal cell and the fourth liquid crystal cell are stacked in a state rotated 90 degrees with respect to the first liquid crystal cell and the second liquid crystal cell.

3. 2. The liquid crystal display device according to claim 1, wherein the second liquid crystal cell and the fourth liquid crystal cell are stacked in a state rotated 90 degrees with respect to the first liquid crystal cell and the third liquid crystal cell.

4. The liquid crystal light control device according to claim 1 , wherein the first electrode generates a transverse electric field between the first strip electrode and the second strip electrode, and the second electrode generates a transverse electric field between the third strip electrode and the fourth strip electrode.

5. 2. The liquid crystal light control device as described in claim 1, wherein the thickness of the liquid crystal layer of the first liquid crystal cell, the second liquid crystal cell, the third liquid crystal cell, and the fourth liquid crystal cell has a length that is at least one time the center-to-center distance between the first strip electrode and the second strip electrode.

6. 2. The liquid crystal light control device according to claim 1, wherein each of the first liquid crystal cell, the second liquid crystal cell, the third liquid crystal cell, and the fourth liquid crystal cell has a liquid crystal layer having a thickness such that a lateral electric field generated at the first electrode does not interfere with a lateral electric field generated at the second electrode.

7. The liquid crystal light control device of claim 1 , wherein the liquid crystal layer is a twisted nematic liquid crystal.

Images