Liquid crystal light control element and lighting device

Abstract

The liquid crystal light control element is configured from a first liquid crystal cell, a second liquid crystal cell, and a third liquid crystal cell each having a first substrate disposed on a light incident side, a second substrate disposed on a light exit side, and a liquid crystal layer between the first substrate and the second substrate. The first liquid crystal cell, the second liquid crystal cell, and the third liquid crystal cell are disposed so as to overlap each other in an emission direction of light emitted from the light source. The first liquid crystal cell has a first electrode that is provided only on one of the first substrate and the second substrate and is configured from a first strip-shaped electrode and a second strip-shaped electrode. The second liquid crystal cell has: a first electrode provided on the first substrate and comprising a first strip-shaped electrode and a second strip-shaped electrode; and a second electrode provided on the second substrate and comprising a third strip-shaped electrode and a fourth strip-shaped electrode. The third liquid crystal cell has a first electrode that is provided only on one of the first substrate and the second substrate and is configured from a first strip electrode and a second strip electrode.

Description

Technical Field

[0001] One embodiment of the present invention relates to a liquid crystal light control element that controls the light distribution of light emitted from a light source using the electro-optical effect of liquid crystal. Another embodiment of the present invention relates to a lighting device including the liquid crystal light control element. Background Art

[0002] A technology has been developed that utilizes the property of liquid crystal that the refractive index changes in response to applied voltage to control the spread of illuminating light (for example, see Patent Documents 1 and 2).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2022 / 176684

[0006] Patent Document 2: International Publication No. 2022 / 202299 Summary of the Invention

[0007] Technical problem to be solved by the invention

[0008] The liquid crystal light control element disclosed in Patent Documents 1 and 2 features a structure consisting of four stacked liquid crystal cells. By embedding liquid crystal cells in lighting equipment, it is possible to illuminate the space and enhance the added value of the product. Meanwhile, the demand for smaller lighting equipment is driving a similar trend for smaller liquid crystal light control elements.

[0009] In view of such technical problems, one object of one embodiment of the present invention is to achieve miniaturization of a liquid crystal light control element.

[0010] Technical solutions to technical problems

[0011] A liquid crystal light control element according to one embodiment of the present invention comprises a first liquid crystal cell, a second liquid crystal cell, and a third liquid crystal cell. The first liquid crystal cell, the second liquid crystal cell, and the third liquid crystal cell each comprise a first substrate disposed on the light incident side, a second substrate disposed on the light emitting side, and a liquid crystal layer between the first and second substrates. The first, second, and third liquid crystal cells are arranged overlapping in the direction of light emitted from a light source. The first liquid crystal cell comprises a first electrode, which is provided on only one of the first and second substrates and is composed of a first strip-shaped electrode and a second strip-shaped electrode. The second liquid crystal cell comprises a first electrode, which is provided on the first substrate and is composed of a first strip-shaped electrode and a second strip-shaped electrode; and a second electrode, which is provided on the second substrate and is composed of a third strip-shaped electrode and a fourth strip-shaped electrode. The third liquid crystal cell comprises a first electrode, which is provided on only one of the first and second substrates and is composed of a first strip-shaped electrode and a second strip-shaped electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1A The structure and diffusion state of a liquid crystal light control element according to one embodiment of the present invention are shown.

[0013] Figure 1B The structure and diffusion state of a liquid crystal light control element according to one embodiment of the present invention are shown.

[0014] Figure 1C The structure and diffusion state of a liquid crystal light control element according to one embodiment of the present invention are shown.

[0015] Figure 1D The structure and diffusion state of a liquid crystal light control element according to one embodiment of the present invention are shown.

[0016] Figure 2A The structure and diffusion state of a liquid crystal light control element according to one embodiment of the present invention are shown.

[0017] Figure 2B The structure and diffusion state of a liquid crystal light control element according to one embodiment of the present invention are shown.

[0018] Figure 2C The structure and diffusion state of a liquid crystal light control element according to one embodiment of the present invention are shown.

[0019] Figure 2D The structure and diffusion state of a liquid crystal light control element according to one embodiment of the present invention are shown.

[0020] Figure 3A The structure and diffusion state of a liquid crystal light control element according to one embodiment of the present invention are shown.

[0021] Figure 3B The structure and diffusion state of a liquid crystal light control element according to one embodiment of the present invention are shown.

[0022] Figure 3C The structure and diffusion state of a liquid crystal light control element according to one embodiment of the present invention are shown.

[0023] Figure 3D The structure and diffusion state of a liquid crystal light control element according to one embodiment of the present invention are shown.

[0024] Figure 4A The structure and diffusion state of a liquid crystal light control element according to one embodiment of the present invention are shown.

[0025] Figure 4BThe structure and diffusion state of a liquid crystal light control element according to one embodiment of the present invention are shown.

[0026] Figure 4C The structure and diffusion state of a liquid crystal light control element according to one embodiment of the present invention are shown.

[0027] Figure 4D The structure and diffusion state of a liquid crystal light control element according to one embodiment of the present invention are shown.

[0028] Figure 5A This is a photograph showing light distribution of a liquid crystal light control element according to one embodiment of the present invention.

[0029] Figure 5B This is a photograph showing light distribution of a liquid crystal light control element according to one embodiment of the present invention.

[0030] Figure 6 This is a graph showing light distribution characteristics of a liquid crystal light control element according to one embodiment of the present invention.

[0031] Figure 7 This is a graph showing light distribution characteristics of a liquid crystal light control element according to one embodiment of the present invention.

[0032] Figure 8 The structure of a liquid crystal light control element according to one embodiment of the present invention is shown.

[0033] Figure 9 This is a graph showing light distribution characteristics of a liquid crystal light control element according to one embodiment of the present invention.

[0034] Figure 10 The structure of a lighting device including a liquid crystal light control element according to one embodiment of the present invention is shown.

[0035] Figure 11 The structure of a liquid crystal cell constituting a liquid crystal light control element according to one embodiment of the present invention is shown in a perspective view.

[0036] Figure 12A A plan view showing electrodes constituting a liquid crystal cell of a liquid crystal light control element according to one embodiment of the present invention.

[0037] Figure 12B A plan view showing electrodes constituting a liquid crystal cell of a liquid crystal light control element according to one embodiment of the present invention.

[0038] Figure 13A This 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 the alignment state of liquid crystal molecules when a voltage is applied.

[0039] Figure 13B This 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 the alignment state of liquid crystal molecules when a voltage is applied.

[0040] Figure 14 The relationship between the voltage applied to the liquid crystal cell constituting the liquid crystal light control element according to one embodiment of the present invention and the light distribution is shown.

[0041] Figure 15A The waveform of a control signal applied to a liquid crystal cell constituting a liquid crystal light control element according to an embodiment of the present invention is shown.

[0042] Figure 15B The waveform of a control signal applied to a liquid crystal cell constituting a liquid crystal light control element according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0043] Hereinafter, the embodiments of the present invention will be described with reference to the accompanying drawings and the like. However, the present invention can be implemented in a variety of different aspects and is not limited to the description of the embodiments illustrated below for explanation. In order to make the description clearer, the accompanying drawings sometimes schematically show the width, thickness, shape, etc. of each part compared to the actual aspects, but this is only an example and does not limit the explanation of the present invention. In addition, in this specification and the figures, the same elements as those described in the figures that have appeared are marked with the same figure marks (or the figure marks such as a, b are marked after the numbers), and the detailed description is sometimes appropriately omitted. Furthermore, the words "first" and "second" attached to each element are convenient identifiers used to distinguish the elements, and have no further meaning unless otherwise specified.

[0044] In this specification, when a component or region is located "above (or below)" other components or regions, unless otherwise specified, it includes not only the case where it is located directly above (or directly below) other components or regions, but also the case where it is located above (or below) other components or regions, that is, it also includes the case where other components are included above (or below) other components or regions.

[0045] In this specification, “optical rotation” refers to a phenomenon in which the polarization axis of a linearly polarized component rotates when the component passes through a liquid crystal layer.

[0046] In this specification, the "alignment direction" of an alignment film refers to the direction in which liquid crystal molecules are aligned when the alignment film is subjected to a treatment that imparts an alignment-regulating force (e.g., a rubbing treatment) to align the liquid crystal molecules on the alignment film. When the alignment film is subjected to a rubbing treatment, the alignment direction of the alignment film is generally the rubbing direction.

[0047] In this specification, the “extending direction” of the strip-shaped electrode refers to the direction in which the long side of a pattern having a short side (width) and a long side (length) extends when the strip-shaped electrode is viewed in a plan view.

[0048] Figure 10 A perspective view of an illumination device 200 according to one embodiment of the present invention is shown. The illumination device 200 includes a liquid crystal light control element 100 and a light source 202. The liquid crystal light control element 100 has a structure in which a first liquid crystal cell 10, a second liquid crystal cell 20, and a third liquid crystal cell 30 are arranged from the light source 202 side. Transparent adhesive layers (not shown) are provided between the first liquid crystal cell 10 and the second liquid crystal cell 20, and between the second liquid crystal cell 20 and the third liquid crystal cell 30. The liquid crystal light control element 100 has a structure in which adjacent liquid crystal cells are bonded to each other via the transparent adhesive layers.

[0049] The liquid crystal light control element 100 is connected to a control circuit (not shown) to control its operation. The liquid crystal light control element 100 and the control circuit are connected via flexible wiring substrates. Specifically, a first flexible wiring substrate F1 is connected to the first liquid crystal cell 10, a second flexible wiring substrate F2 is connected to the second liquid crystal cell 20, and a third flexible wiring substrate F3 is connected to the third liquid crystal cell 30.

[0050] Figure 10 The illustrated lighting device 200 is configured such that light emitted from a light source 202 passes through a liquid crystal light control element 100 and is emitted toward the front of the drawing. Light source 202 comprises a white light source, and optical elements such as lenses may be positioned between the white light source and the liquid crystal light control element 100 as needed. A white light source emits light that approximates natural light, or may emit light that has been dimmed, such as daylight white or light bulb color. Light source 202 ideally comprises a light source with a narrow light distribution range. For example, it preferably has a structure that combines an LED light source with a reflector, lens, and the like.

[0051] Figure 11 This is a perspective view of the liquid crystal cell 10. The liquid crystal cell 10 includes a first substrate S11, a second substrate S12, a first electrode E11, a second electrode E12, a first alignment film AL11, a second alignment film AL12, and a first liquid crystal layer LC1. The first electrode E11 is provided on the first substrate S11, and the second electrode E12 is provided on the second substrate S12. The first alignment film AL11 is provided on the first substrate S11 to cover the first electrode E11, and the second alignment film AL12 is provided on the second substrate S12 to cover the second electrode E12. The liquid crystal layer LC1 is provided between the first substrate S11 and the second substrate S12. The first electrode E11 and the second electrode E12 are arranged to face each other with the first liquid crystal layer LC1 interposed therebetween.

[0052] The first electrode E11 includes a first strip electrode E11A and a second strip electrode E11B, each having a strip-shaped pattern (or a comb-shaped pattern). The second electrode E12 includes a third strip electrode E12A and a fourth strip electrode E12B, each having a strip-shaped pattern (or a comb-shaped pattern). The first strip electrodes E11A and the second strip electrodes E11B are alternately arranged on the insulating surface of the first substrate S11, while the third strip electrodes E12A and the fourth strip electrodes E12B are alternately arranged on the insulating surface of the second substrate S12.

[0053] For illustration purposes, Figure 11 The X, Y, and Z axis directions are shown. In the liquid crystal cell 10, the first strip-shaped electrode E11A and the plurality of second strip-shaped electrodes E11B extend in a direction parallel to the X axis, while the third strip-shaped electrode E12A and the plurality of fourth strip-shaped electrodes E12B extend in a direction parallel to the Y axis. In other words, the third strip-shaped electrode E12A and the fourth strip-shaped electrode E12B are arranged to intersect the first strip-shaped electrode E11A and the second strip-shaped electrode E11B. The extending directions of the first strip-shaped electrode E11A and the second strip-shaped electrode E11B intersect with the extending directions of the third strip-shaped electrode E12A and the fourth strip-shaped electrode E12B, for example, within a range of 90±10 degrees, preferably at right angles (90 degrees).

[0054] It should be noted that the strip electrodes constituting the first electrode E11 and the second electrode E12 may extend in a direction inclined by approximately ±10 degrees relative to the X-axis and the Y-axis. Furthermore, the strip electrodes may also be configured to extend in a predetermined direction while being partially bent. In this case, the strip electrodes may have multiple longitudinal extension directions, but each extension direction may be inclined by approximately ±10 degrees relative to the X-axis and the Y-axis. Similarly, the strip electrodes may extend in a predetermined direction while being partially bent. In this case, the tangent direction at each position of the strip electrode may be considered the extension direction, with each extension direction inclined by approximately ±10 degrees relative to the X-axis and the Y-axis.

[0055] The alignment direction ALD1 of the first alignment film AL11 is set to intersect the extending direction of the first strip electrode E11A and the second strip electrode E11B (the Y-axis direction). The alignment direction ALD2 of the second alignment film AL12 is set to intersect the extending direction of the third strip electrode E12A and the fourth strip electrode E12B (the X-axis direction). The angles at which the extending directions of the first strip electrode E11A and the second strip electrode E11B intersect the alignment direction ALD1, and the angle at which the extending directions of the third strip electrode E12A and the fourth strip electrode E12B intersect the alignment direction ALD2, can be set within a range of 90±10 degrees.

[0056] The gap between the first substrate S11 and the second substrate S12 (hereinafter sometimes referred to as "cell gap") can be appropriately set within the range of 10μm to 100μm, preferably 15μm to 55μm. Compared to the gap between the first substrate S11 and the second substrate S12, the thickness of the first electrode E11 and the second electrode E12 and the first alignment film AL11 and the second alignment film AL12 are so small that they can be ignored. Therefore, the gap between the first substrate S11 and the second substrate S12 can be regarded as the thickness of the first liquid crystal layer LC1. Although Figure 11 Although not shown in the figure, a spacer for maintaining a constant distance between the first substrate S11 and the second substrate S12 may be provided.

[0057] The first liquid crystal layer LC1 uses, for example, twisted nematic liquid crystal (TN (Twisted Nematic) liquid crystal). When no voltage is applied to the first and second electrodes E11 and E12, the first liquid crystal layer LC1, influenced by the alignment-regulating forces of the first and second alignment films AL11 and AL12, aligns the liquid crystal molecules LCM in such a way that their long axes are parallel to the alignment directions ALD1 and ALD2 of the alignment films. The alignment direction ALD1 of the first alignment film AL11 intersects (is perpendicular to) the alignment direction ALD2 of the second alignment film AL12, causing the long axis of the liquid crystal molecules LCM to gradually change in a 90-degree twist from the first substrate S11 to the second substrate S12.

[0058] Relative to Figure 11 The initial alignment state of the liquid crystal molecules LCM shown in FIG. By applying a voltage to generate a potential difference between the first strip electrode E11A and the second strip electrode E11B, the alignment state of the liquid crystal molecules LCM on the first substrate S11 side is changed. Furthermore, by applying a voltage to generate a potential difference between the third strip electrode E12A and the fourth strip electrode E12B, the alignment state of the liquid crystal molecules LCM on the second substrate S12 side is changed.

[0059] Figure 12A shows a top view of the first substrate S11, Figure 12B 1 shows a top view of the second substrate S12. Figure 12A and Figure 12B As shown, the first electrode E11 has a structure in which a plurality of first strip electrodes E11A and a plurality of second strip electrodes E11B are alternately arranged at predetermined intervals, and the second electrode E12 has a structure in which a plurality of third strip electrodes E12A and a plurality of fourth strip electrodes E12B are alternately arranged at predetermined intervals.

[0060] like Figure 12AAs shown, multiple first strip electrodes E11A are each connected to a first power supply line PE11, and multiple second strip electrodes E11B are each connected to a second power supply line PE12. The first power supply line PE11 is connected to a first connection terminal T11, and the second power supply line PE12 is connected to a second connection terminal T12. The first and second connection terminals T11 and T12 are arranged along one side of an end portion of the first substrate S11. On the first substrate S11, a third connection terminal T13 is arranged adjacent to the first connection terminal T11, and a fourth connection terminal T14 is arranged adjacent to the second connection terminal T12. The third connection terminal T13 is connected to a fifth power supply line PE15. The fifth power supply line PE15 is connected to a first power supply terminal PT11 located at a predetermined position within the surface of the first substrate S11. The fourth connection terminal T14 is connected to a sixth power supply line PE16. The sixth power supply line PE16 is connected to a second power supply terminal PT12 located at a predetermined position within the surface of the first substrate S11.

[0061] The plurality of first strip-shaped electrodes E11A are connected to the first power supply line PE11, to which the same voltage is applied. The plurality of second strip-shaped electrodes E11B are connected to the second power supply line PE12, to which the same voltage is applied. When different voltages are applied to the first connection terminal T11 and the second connection terminal T12, an electric field is generated between the plurality of first strip-shaped electrodes E11A and the plurality of second strip-shaped electrodes E11B.

[0062] like Figure 12B As shown, multiple third strip electrodes E12A are respectively connected to third power supply lines PE13, and multiple fourth strip electrodes E12B are respectively connected to fourth power supply lines PE14. The third power supply line PE13 is connected to the third connection terminal T13, and the fourth power supply line PE14 is connected to the fourth connection terminal T14. 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. The third power supply terminal PT13 is electrically connected to the first power supply terminal PT11, and the fourth power supply terminal PT14 is electrically connected to the second power supply terminal PT12. Conductive paste is used to electrically connect these power supply terminals. Silver paste is used as the conductive paste, for example.

[0063] When different voltages are applied to the third connection terminal T13 and the fourth connection terminal T14, an electric field is generated between the third strip electrodes E12A and the fourth strip electrodes E12B. In other words, a transverse electric field is generated through the third strip electrodes E12A and the fourth strip electrodes E12B.

[0064] The first substrate S11 and the second substrate S12 are light-transmitting substrates, such as glass or resin substrates. The first electrode E11 and the second electrode E12 are transparent electrodes formed from a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). The power lines (first power line PE11, second power line PE12, third power line PE13, and fourth power line PE14) and the connection terminals (first connection terminal T11, second connection terminal T12, third connection terminal T13, and fourth connection terminal T14) are formed from a metal material such as aluminum, titanium, molybdenum, or tungsten. It should be noted that the power lines (first power line PE11, second power line PE12, third power line PE13, and fourth power line PE14) can also be formed from the same transparent conductive film as the first and second electrodes E11 and E12. Alternatively, a structure can be employed in which either or both of the first and second electrodes E11 and E12 are formed from a metal material or by overlaying a metal material on a transparent conductive film.

[0065] Figure 13A FIG. 1 is a partial cross-sectional view of the liquid crystal cell 10 when viewed from a direction perpendicular to the direction in which the third strip-shaped electrodes E12A extend. Figure 13B FIG. 1 shows a partial cross-sectional view of the liquid crystal cell 10 when viewed from a direction perpendicular to the direction in which the first strip-shaped electrodes E11A extend. Figure 13A and Figure 13B The symbols indicate that the alignment direction ALD1 of the first alignment film AL11 is different from the alignment direction ALD2 of the second alignment film AL12 .

[0066] like Figure 13A and Figure 13B As shown, the first substrate S11 and the second substrate S12 are arranged opposite to each other with a distance D. As mentioned above, the distance D is the distance between the substrates, but is actually equivalent to the thickness of the first liquid crystal layer LC1. Figure 13A and Figure 13B The center-to-center distance MW between the first strip-shaped electrode E11A and the second strip-shaped electrode E11B, and between the third strip-shaped electrode E12A and the fourth strip-shaped electrode E12B is shown.

[0067] Here, the distance D corresponding to the thickness of the first liquid crystal layer LC1 is preferably equal to or greater than the center-to-center distance MW of the strip electrodes (D ≥ MW). In other words, the distance D is preferably at least twice the center-to-center distance MW. For example, the distance D corresponding to the thickness of the first liquid crystal layer LC1 is preferably at least twice the center-to-center distance MW of the strip electrodes. For example, when the center-to-center distance MW is 16 μm, the distance D corresponding to the thickness of the first liquid crystal layer LC1 is preferably at least 16 μm, for example, preferably 20 μm, and more preferably 30 μm.

[0068] By setting the center-to-center distance MW of the strip electrodes to the interval D corresponding to the thickness of the first liquid crystal layer LC1 in this manner, the electric field generated between the first strip electrode E11A and the second strip electrode E11B and the electric field generated between the third strip electrode E12A and the fourth strip electrode E12B are prevented from interfering with each other.

[0069] It is known that the refractive index of liquid crystals changes depending on their orientation. In the OFF state (when no electric field is applied to the first liquid crystal layer LC1), the long axes of the liquid crystal molecules LCM are aligned horizontally on the substrate surfaces and twisted 90 degrees from the first substrate S11 side to the second substrate S12 side. In this state, the first liquid crystal layer LC1 has a uniform refractive index distribution. When light enters the liquid crystal cell 10, the polarization component of the incident light is shifted due to the twisting of the liquid crystal molecules LCM. In this case, the incident light passes through the first liquid crystal layer LC1 without being refracted (or scattered) while undergoing optical rotation.

[0070] On the other hand, Figure 13A As shown in FIG. 1 , when an electric field is generated between the first strip electrode E11A and the second strip electrode E11B, the liquid crystal molecules LCM are aligned such that their long axes are aligned with the electric field (when the liquid crystal has positive dielectric anisotropy). As a result, Figure 13A As shown, in the first liquid crystal layer LC1, liquid crystal molecules LCM are formed in an area where they stand above the first strip electrode E11A and the second strip electrode E11B, an area where they are oriented obliquely along the distribution of the electric field between the first strip electrode E11A and the second strip electrode E11B, and an area where the initial orientation state is maintained in an area away from the first substrate S11.

[0071] Likewise, if Figure 13B As shown, when the electric field is generated between the third strip electrode E12A and the fourth strip electrode E12B and is in the on (ON) state, a region in which the liquid crystal molecules LCM stand upright above the third strip electrode E12A and the fourth strip electrode E12B, a region in which the liquid crystal molecules LCM are oriented obliquely along the distribution of the electric field between the third strip electrode E12A and the fourth strip electrode E12B, and a region in which the initial orientation state is maintained in a region away from the second substrate S12 are formed in the first liquid crystal layer LC1.

[0072] Hereinafter, the electric field generated by the first strip-shaped electrode E11A, the second strip-shaped electrode E11B, the third strip-shaped electrode E12A, and the fourth strip-shaped electrode E12B is also referred to as a “transverse electric field”.

[0073] like Figure 13A and Figure 13BAs shown, when an electric field is generated between the first strip electrode E11A and the second strip electrode E11B, and between the third strip electrode E12A and the fourth strip electrode E12B, a region is formed in which the liquid crystal molecules LCM are oriented in a convex arc shape with the long axis of the liquid crystal molecules along the direction of the electric field. Figure 13A As shown, when the direction of the initial orientation of the liquid crystal molecules LCM is the same as the direction of the lateral electric field generated between the first strip electrode E11A and the second strip electrode E11B, the liquid crystal molecules LCM are oriented tilted (obliquely) toward the normal direction relative to the surface of the first substrate S11 according to the intensity distribution of the electric field.

[0074] At this time, if Figure 13A As shown, since the gap D equivalent to the thickness of the first liquid crystal layer LC1 is large enough, the electric field on the first substrate S11 side has a significantly smaller effect on the orientation of the liquid crystal molecules on the second substrate S12 side, and the orientation state of the liquid crystal molecules LCM on the second substrate S12 side is almost unaffected by the electric field generated on the first substrate S11 side. Figure 13B Similarly, the liquid crystal molecules LCM on the second substrate S12 side are affected by the electric field generated by the third strip electrodes E12A and the fourth strip electrodes E12B and their alignment state changes, but the liquid crystal molecules LCM on the first substrate S11 side are hardly affected by the electric field.

[0075] By forming a lateral electric field through the strip electrodes, a convex arc-shaped dielectric constant distribution is formed in the first liquid crystal layer LC1. The polarization component of the light incident on the first liquid crystal layer LC1 that is parallel to the initial orientation direction of the liquid crystal molecules LCM is radially diffused due to the dielectric constant distribution. Figure 13A and Figure 13B As shown, the initial alignment directions of the liquid crystal molecules LCM intersect (are orthogonal) on the first substrate S11 side and the second substrate S12 side, so that light can be diffused in different directions on the first substrate S11 side and the second substrate S12 side.

[0076] Thus, when light passes through the liquid crystal cell 10 , a state can be formed in which a part of the polarization component is diffused and transmitted according to the electric field formation condition in the first liquid crystal layer LC1 , and the remaining polarization component directly transmits the first liquid crystal layer LC1 .

[0077] Figure 14 In the liquid crystal cell 10 , the first strip electrodes E11A and the second strip electrodes E11B of the first electrodes E11 extend in the X-axis direction, and the third strip electrodes E12A and the fourth strip electrodes E12B of the second electrodes E12 extend in the Y-axis direction. Figure 14The figure also shows a state where a voltage VH is applied to the first strip electrode E11A, a voltage VL is applied to the second strip electrode E11B (VL < VH), a voltage VH is applied to the third strip electrode E12A, and a voltage VL is applied to the fourth strip electrode E12B (VL < VH). These voltage application conditions generate a transverse electric field in the Y-axis direction on the first substrate S11 side and a transverse electric field in the X-axis direction on the second substrate S12 side.

[0078] Figure 14 The light emitted from the light source has a first polarization component PL1 and a second polarization component PL2. The first polarization component PL1 corresponds to an S wave, and the second polarization component PL2 corresponds to a P wave. Here, it is assumed that the S wave has an amplitude in the Y-axis direction and the P wave has an amplitude in the X-axis direction. And, as shown in FIG. Figure 14 As shown in the table, light incident on the liquid crystal cell 10 is subject to optical effects such as transmission, optical rotation, and diffusion. "Transmission" in the table means that the polarization axis of a given polarization component remains unchanged, and the light distribution remains unchanged, allowing it to pass through without changing. As mentioned above, "optical rotation" refers to the phenomenon in which the polarization axis of a linearly polarized component rotates when it passes through the liquid crystal layer. Furthermore, "Diffusion (X)" indicates diffusion of the polarization component in the X-axis direction, and "Diffusion (Y)" indicates diffusion of the polarization component in the Y-axis direction. Figure 14 The descriptions shown in the table are the same in each embodiment described later.

[0079] Figure 14 The liquid crystal cell 10 is shown in a state where light including a first polarization component PL1 (S wave) and a second polarization component PL2 (P wave) is incident on a first substrate S11 and emitted from a second substrate S12 .

[0080] Although not shown, the alignment direction ALD1 of the first alignment film AL1 is parallel to the X-axis, and the alignment direction ALD2 of the second alignment film AL2 is parallel to the Y-axis. The alignment direction of the liquid crystal molecules LCM in the first liquid crystal layer LC1 is influenced by the alignment restraining forces of these alignment films. Therefore, the long axes of the liquid crystal molecules LCM on the first substrate S11 side are oriented in the Y-axis direction, while the long axes of the liquid crystal molecules LCM on the second substrate S12 side are oriented in the X-axis direction.

[0081] Of the light incident from the first substrate S11, the first polarization component PL1 is in an S-wave state. On the first electrode E11 side, its polarization direction is parallel to the long axis of the liquid crystal molecules LCM. Therefore, it is influenced by the arc-shaped refractive index distribution formed by the orientation of the liquid crystal molecules LCM and diffuses in the Y-axis direction. Then, within the first liquid crystal layer LC1, the first polarization component PL1 travels from the first substrate S11 side to the second substrate S12 side, undergoing, for example, a 90-degree optical rotation, transforming into a P-wave state. On the second electrode E12 side, the first polarization component PL1 is in a polarization direction parallel to the long axis of the liquid crystal molecules LCM. Therefore, it is influenced by the arc-shaped refractive index distribution formed by the orientation of the liquid crystal molecules LCM and diffuses in the X-axis direction. Meanwhile, the second polarization component PL2 is in a P-wave state. On the first electrode E11 side, its polarization direction intersects the long axis of the liquid crystal molecules LCM. Therefore, it is not affected by the arc-shaped refractive index distribution formed by the orientation of the liquid crystal molecules LCM and is transmitted directly. The second polarization component PL2 travels in the first liquid crystal layer LC1 from the first substrate S11 side toward the second substrate S12 side, undergoing optical rotation by, for example, 90 degrees, and transforming into an S-wave state. Since the second polarization component PL2 is an S-wave, its polarization direction intersects the long axis direction of the liquid crystal molecules LCM on the second electrode E12 side, and thus is transmitted directly through the liquid crystal layer LC1 without being affected by the arc-shaped refractive index distribution formed by the orientation of the liquid crystal molecules LCM.

[0082] Thus, when light is incident on Figure 14 In the liquid crystal unit 10 shown, the first polarization component PL1 (S wave) diffuses once in the X-axis direction and the Y-axis direction, is optically rotated in the first liquid crystal layer LC1, and is emitted as a P wave. The second polarization component PL2 (P wave) is not diffused, is optically rotated in the first liquid crystal layer LC1, and is emitted as an S wave.

[0083] It should be noted that Figure 14 Although the structure shown here shows electrodes for controlling the alignment state of the liquid crystal molecules LCM provided on both the first substrate S11 and the second substrate S12, the liquid crystal cell may also have a structure in which such electrodes are provided on only one substrate. For example, the liquid crystal cell may also have a structure in which such electrodes are provided on only the first substrate S11 side or the second substrate S12 side.

[0084] The liquid crystal light control element 100 according to one embodiment of the present invention is capable of distributing light emitted from a light source into various shapes by stacking three liquid crystal cells having the same structure as the liquid crystal cell 10. More specifically, the liquid crystal cell 10 described above is used as a typical example. A liquid crystal cell obtained by removing some electrodes from the typical example, a liquid crystal cell obtained by rotating the typical example 90 degrees about the Z axis, or a combination of these is employed. These are described in detail below.

[0085] [First embodiment]

[0086] Figure 1A The structure of the liquid crystal light control element 100A according to the first embodiment is shown. The liquid crystal light control element 100A has a structure in which a first liquid crystal cell 10, a second liquid crystal cell 20, and a third liquid crystal cell 30 are stacked in the Z-axis direction. Figure 1A Although the light source is not shown, light emitted from the light source sequentially passes through the first liquid crystal cell 10, the second liquid crystal cell 20, and the third liquid crystal cell 30 and is emitted into the illumination space. The first liquid crystal cell 10, the second liquid crystal cell 20, and the third liquid crystal cell 30 are respectively provided with first substrates S11, S21, and S31 on the light incident side and second substrates S12, S22, and S23 on the light exiting side.

[0087] It should be noted that for the purpose of explanation, Figure 1A Although the liquid crystal cells are shown as being separated, the actual liquid crystal light control element 100A has a structure in which the liquid crystal cells are bonded together using a light-transmitting adhesive. Figure 1A For simplicity, the illustration of the alignment film is omitted. The annotations thereon are the same as those for the other drawings shown in this embodiment and the other drawings shown in other embodiments.

[0088] The first liquid crystal unit 10 has the same structure as the first liquid crystal unit 10 except that the second electrode E12 is not provided on the second substrate S12. Figure 14 The first liquid crystal cell 10 has a similar structure to the liquid crystal cell 10 shown in FIG. The first liquid crystal cell 10 has a structure in which only the first electrode E11 is provided on the first substrate S11, and no electrodes for controlling the alignment of the liquid crystal molecules LCM are provided on the second substrate S12. The first strip-shaped electrode E11A and the second strip-shaped electrode E11B constituting the first electrode E11 extend in the X-axis direction.

[0089] The second liquid crystal unit 20 has Figure 14 The liquid crystal cell 10 shown has a similar structure, with a first electrode E21 disposed on the first substrate S21 side, and a second electrode E22 disposed on the second substrate S22 side via a second liquid crystal layer LC2. The first strip electrodes E21A and the second strip electrodes E21B of the first electrode E21 extend in the X-axis direction, while the third strip electrodes E22A and the fourth strip electrodes E22B of the second electrode E22 extend in the Y-axis direction.

[0090] The third liquid crystal unit 30 has the same structure as the first substrate S31 except that the second electrode E32 is provided on the second substrate S32 and no electrode for controlling the alignment state of the liquid crystal molecules LCM is provided on the first substrate S31. Figure 14The structure is the same as that of the liquid crystal cell 10. The third strip-shaped electrode E32A and the fourth strip-shaped electrode E32B of the second electrode E32 extend in the Y-axis direction.

[0091] It should be noted that in the first liquid crystal cell 10, an alignment film (not shown) is provided on the second substrate S12, and its alignment direction ALD2 is arranged to intersect (orthogonally) with the alignment direction ALD1 of the alignment film on the first substrate S11. Furthermore, in the third liquid crystal cell 30, an alignment film (not shown) is provided on the first substrate S31, and its alignment direction ALD1 is arranged to intersect (orthogonally) with the alignment direction ALD2 of the alignment film on the second substrate S32.

[0092] The first liquid crystal unit 10 , the second liquid crystal unit 20 , and the third liquid crystal unit 30 are driven by control signals LH1 , HL1 , and CV. Figure 15A The waveforms of control signals LH1, HL1, and CV are shown. Control signal LH1 is a signal whose voltage level changes from VL1 to VH1 and vice versa, while control signal HL1 is a signal whose voltage level changes periodically from VH1 to VL1 and vice versa. Low-level voltage VL1 is, for example, 0V or -15V, while high-level voltage VH1 is, for example, 30V (relative to VL1 = 0V) or 15V (relative to VL1 = -15V). Control signal LH1 is synchronized with control signal HL1. When control signal LH1 is at VH1, control signal HL1 is at VL1. When control signal LH1 changes to VL1, control signal HL1 changes to VH1. The period of control signals LH1 and HL1 is approximately 15 to 100 Hz. Control signal CV, on the other hand, is a constant voltage signal, for example, a voltage intermediate between VL1 and VH1 or a voltage signal of 0V.

[0093] Figure 1A The following state is shown: a control signal CV is applied to the first strip electrode E11A and the second strip electrode E11B of the first liquid crystal unit 10, a control signal CV is applied to the first strip electrode E21A and the second strip electrode E21B of the second liquid crystal unit 20, a control signal LH1 is applied to the third strip electrode E22A, a control signal HL1 is applied to the fourth strip electrode E22B, a control signal LH1 is applied to the third strip electrode E32A of the third liquid crystal unit 30, and a control signal HL1 is applied to the fourth strip electrode E32B.

[0094] If inserted Figure 1AAs shown in the table, the first polarization component PL1 (S wave) of light emitted from the light source is optically rotated into a P wave state in the third liquid crystal layer LC3 of the first liquid crystal cell 10, the second liquid crystal cell 20, and the third liquid crystal cell 30, respectively. It is diffused in the X-axis direction by the second electrode E32 of the third liquid crystal cell 30 and then emitted. Furthermore, the second polarization component PL2 (P wave) is optically rotated into a P wave state in the second liquid crystal layer LC2 of the first liquid crystal cell 10 and the second liquid crystal cell 20, diffused in the X-axis direction by the second electrode E22 of the second liquid crystal cell 20, and then optically rotated in the third liquid crystal cell 30 and emitted as an S wave.

[0095] It should be noted that in this embodiment, focusing on the second liquid crystal cell 20, the first electrode E21 of the first substrate S21 and the second electrode E22 of the second substrate S22 are orthogonal to each other, and the optical rotation described above essentially means optical rotation to 90 degrees. Here, when these electrodes intersect at an angle less than 90 degrees, the angle of optical rotation is less than 90 degrees. In other words, the angle of "optical rotation" described above is determined based on the intersection angle between the first electrode E21 and the second electrode E22, and optical rotation at 90 degrees can naturally include optical rotation at angles less than 90 degrees. In other words, the angle of "optical rotation" described above can also be said to be determined based on the intersection angle between the alignment direction ALD1 of the alignment film on the first substrate E21 side and the alignment direction ALD2 of the alignment film on the second substrate E22 side. Depending on the intersection angle of the alignment directions of the alignment films, optical rotation at 90 degrees can naturally include optical rotation at angles less than 90 degrees. The same applies to the first liquid crystal cell 10 and the third liquid crystal cell 30. This also applies to the other embodiments described below.

[0096] Therefore, the liquid crystal light control element 100A is Figure 1A Under the control signal application conditions shown, the first polarization component PL1 and the second polarization component PL2 are optically rotated while each polarization component PL1 and PL2 is diffused once in the X-axis direction. This diffuses the light from the light source in the X-axis direction as a whole before emitting it. In other words, the liquid crystal light control element 100A can expand the light distribution of the light emitted from the light source in the X-axis direction. This light distribution pattern can be referred to as linear light distribution.

[0097] Figure 1B The following state is shown: a control signal LH1 is applied to the first strip electrode E11A of the first liquid crystal unit 10, a control signal HL1 is applied to the second strip electrode E11B, a control signal LH1 is applied to the first strip electrode E21A of the second liquid crystal unit 20, a control signal HL1 is applied to the second strip electrode E21B, a control signal CV is applied to the third strip electrode E22A and the fourth strip electrode E22B, and a control signal CV is applied to the third strip electrode E32A and the fourth strip electrode E32B of the third liquid crystal unit 30.

[0098] If inserted Figure 1B As shown in the table, the first polarization component PL1 (S wave) of light emitted from the light source is diffused in the Y-axis direction by the first electrode E11 of the first liquid crystal cell 10, optically rotated in the first liquid crystal layer LC1 of the first liquid crystal cell 10, the second liquid crystal cell 20, and the third liquid crystal cell 30, and emitted as a P wave. Furthermore, the second polarization component PL2 (P wave) is optically rotated in the first liquid crystal cell 10 to become an S wave, diffused in the Y-axis direction by the first electrode E21 of the second liquid crystal cell 20, and optically rotated in the second liquid crystal layer LC2 of the second liquid crystal cell 20 and the third liquid crystal cell 30, and emitted as an S wave.

[0099] Therefore, the liquid crystal light control element 100A is Figure 1B Under the control signal application conditions shown in FIG. 1 , the first polarization component PL1 and the second polarization component PL2 are optically rotated while each polarization component PL1 and PL2 is diffused once in the Y-axis direction, thereby diffusing the light from the light source in the Y-axis direction as a whole and emitting the light. In other words, the liquid crystal light control element 100A can expand the light distribution state of the light emitted from the light source in the Y-axis direction. Such a light distribution pattern can be used with Figure 1A The same situation is called line light distribution.

[0100] Figure 1C The following state is shown: a control signal LH1 is applied to the first strip electrode E11A of the first liquid crystal unit 10, a control signal HL1 is applied to the second strip electrode E11B, a control signal LH1 is applied to the first strip electrode E21A of the second liquid crystal unit 20, a control signal HL1 is applied to the second strip electrode E21B, a control signal LH1 is applied to the third strip electrode E22A, a control signal HL1 is applied to the fourth strip electrode E22B, a control signal LH1 is applied to the third strip electrode E32A of the third liquid crystal unit 30, and a control signal HL1 is applied to the fourth strip electrode E32B.

[0101] If inserted Figure 1CAs shown in the table, the first polarization component PL1 (S wave) of light emitted from the light source is diffused in the Y-axis direction by the first electrode E11 of the first liquid crystal cell 10, optically rotated into a P-wave state in the first liquid crystal layer LC1, the second liquid crystal cell 20, and the third liquid crystal cell 30, respectively. It is then diffused in the X-axis direction by the second electrode E32 and emitted. Furthermore, the second polarization component PL2 (P wave) is optically rotated into an S-wave state in the first liquid crystal cell 10, diffused in the Y-axis direction by the first electrode E21 of the second liquid crystal cell 20, optically rotated into a P-wave state in the second liquid crystal layer LC2, diffused in the X-axis direction by the second electrode E22, and optically rotated into an S-wave state in the third liquid crystal cell 30 before being emitted.

[0102] Therefore, the liquid crystal light control element 100A is Figure 1C The control signal application conditions shown in the figure cause the first polarization component PL1 and the second polarization component PL2 to be optically rotated while simultaneously diffusing each polarization component PL1 and PL2 once in the X-axis and Y-axis directions. In other words, by diffusing at least one polarization component not only in one direction but also in two intersecting directions (in this embodiment, the X-axis and Y-axis directions), the light distribution of the light emitted from the light source can be expanded in the X-axis and Y-axis directions. This light distribution pattern is called circular light distribution.

[0103] By the way, Figure 15B Shown with Figure 15A An example of different control signals. Control signals LH1, HL1 and reference Figure 15A The signals described are the same. Control signal LH2 is a signal whose voltage level changes from VL2 to VH2 and from VH2 to VL2, while control signal HL2 is a signal whose voltage level changes periodically from VH2 to VL2 and from VL2 to VH2. Low-level voltage VL2 is, for example, 0V or -30V, while high-level voltage VH2 is, for example, 60V (relative to VL2 = 0V) or 30V (relative to VL1 = -30V). Control signal LH2 is synchronized with control signal HL2. When control signal LH2 is at VH2, control signal HL2 is at VL2. When control signal LH2 changes to VL2, control signal HL2 changes to VH2. The cycles of control signals LH2 and HL2 are the same as those of control signals LH1 and HL1.

[0104] By using such two-level control signals, Figure 1CThe circular light distribution in the image is converted to an elliptical light distribution. More specifically, a control signal LH1 is applied to the first strip-shaped electrode E11A of the first liquid crystal cell 10, and a control signal HL1 is applied to the second strip-shaped electrode E11B. A control signal LH1 is applied to the first strip-shaped electrode E21A of the second liquid crystal cell 20, and a control signal HL1 is applied to the second strip-shaped electrode E21B. Furthermore, a control signal LH2 is applied to the third strip-shaped electrode E22A, and a control signal HL2 is applied to the fourth strip-shaped electrode E22B. A control signal LH2 is applied to the third strip-shaped electrode E32A of the third liquid crystal cell 30, and a control signal HL2 is applied to the fourth strip-shaped electrode E32B.

[0105] This allows for an elliptical light distribution with a greater degree of diffusion in the X-axis direction than in the Y-axis direction. By completely swapping control signals LH1 and LH2, and completely swapping control signals HL1 and HL2, it is possible to achieve an elliptical light distribution with a greater degree of diffusion in the Y-axis direction than in the X-axis direction.

[0106] Figure 1D The first liquid crystal cell 10 and the second liquid crystal cell 20 are shown. Figure 15B An example of control signals having different voltage levels as shown is shown. Specifically, the following state is shown: a control signal LH1 is applied to the first strip electrode E11A of the first liquid crystal cell 10, a control signal HL1 is applied to the second strip electrode E11B, a control signal CV is applied to the first strip electrode E21A and the second strip electrode E21B of the second liquid crystal cell 20, a control signal LH2 is applied to the third strip electrode E22A, a control signal HL2 is applied to the fourth strip electrode E22B, and a control signal CV is applied to the third strip electrode E32A and the fourth strip electrode E32B of the third liquid crystal cell 30.

[0107] If inserted Figure 1D As shown in the table, the first polarization component PL1 (S wave) of light emitted from the light source is diffused in the Y-axis direction by the first electrode E11 of the first liquid crystal cell 10, optically rotated in the first liquid crystal layer LC1, the second liquid crystal cell 20, and the third liquid crystal cell 30, and emitted as a P wave. Furthermore, the second polarization component PL2 (P wave) is optically rotated in the second liquid crystal layer LC2 of the first liquid crystal cell 10 and the second liquid crystal cell 20, diffused in the X-axis direction by the second electrode E22, and optically rotated in the third liquid crystal cell 30, and emitted as an S wave.

[0108] Therefore, the liquid crystal light control element 100A is Figure 1DUnder the control signal application conditions shown, while optically rotating the first polarization component PL1 and the second polarization component PL2, the control signals LH1 and HL1 diffuse the first polarization component PL1 once in the Y-axis direction and emit it, while the control signals LH2 and HL2 diffuse the second polarization component PL2 once in the X-axis direction and emit it. In other words, the liquid crystal light control element 100A can distribute light emitted from the light source by diffusing the first polarization component PL1 only in the Y-axis direction and the second polarization component PL2 only in the X-axis direction. By controlling each polarization component to diffuse independently in specific directions in this way, a cross-shaped light distribution pattern can be formed. This light distribution pattern can be referred to as a cross light distribution pattern. In this case, because the amplitudes of the control signals LH2 and HL2 applied to the second electrode E22 of the second liquid crystal cell 20 are greater than the amplitudes of the control signals LH1 and HL21, a state of greater diffusion (widespread) in the X-axis direction is achieved. That is, the liquid crystal light control element 100A can distribute the light emitted from the light source by greatly extending it in the X-axis direction relative to the Y-axis direction. In other words, by changing the voltage level of the control signal, the extension of the cross (the length in the X-axis direction and the length in the Y-axis direction) can be changed when performing cross light distribution. It should be noted that Figure 1D In the embodiment, even if the control signals LH2 and HL2 applied to the second liquid crystal cell 20 are replaced with the control signals LH1 and HL1 applied to the first liquid crystal cell 10 , the cross light distribution can be realized in the same manner.

[0109] As described above, the liquid crystal light control element 100A of this embodiment can change the light emitted from a light source into various light distribution states using three liquid crystal cells. The liquid crystal light control element 100A of this embodiment is composed of three liquid crystal cells, thus achieving a thinner form factor, thereby enabling a more compact lighting device.

[0110] [Second embodiment]

[0111] Figure 2A The structure of the liquid crystal light control element 100B according to the second embodiment is shown. Compared with the liquid crystal light control element 100A according to the first embodiment, the liquid crystal light control element 100B according to this embodiment is different in that: in the first liquid crystal unit 10, no electrode is provided on the first substrate S11 side, and a second electrode E12 is provided on the second substrate S12 side; in the third liquid crystal unit 30, a first electrode E31 is provided on the first substrate S31 side, and no electrode is provided on the second substrate S32 side. It should be noted that, as Figure 2A As shown, an alignment film is also provided on the first substrate S11 without electrodes, and its alignment direction ALD1 intersects with the alignment direction ALD2 of the light distribution film on the second substrate S12 with electrodes in the same unit. Figures 2B to 2DThe same is true.

[0112] Figure 2A The following state is shown: a control signal LH1 is applied to the third strip electrode E12A of the first liquid crystal unit 10, a control signal HL1 is applied to the fourth strip electrode E12B, a control signal CV is applied to the first strip electrode E21A and the second strip electrode E21B of the second liquid crystal unit 20, a control signal LH1 is applied to the third strip electrode E22A, a control signal HL1 is applied to the fourth strip electrode E22B, and a control signal CV is applied to the first strip electrode E31A and the second strip electrode E31B of the third liquid crystal unit 30.

[0113] If inserted Figure 2A As shown in the table, the first polarization component PL1 (S wave) of light emitted from the light source is optically rotated in the first liquid crystal layer LC1 of the first liquid crystal cell 10 to a P wave state. It is diffused in the X-axis direction by the second electrode E12, and then optically rotated in each of the second and third liquid crystal cells 20 and 30 to be emitted as a P wave. Furthermore, the second polarization component PL2 (P wave) is optically rotated in the first liquid crystal cell 10, then optically rotated in the second liquid crystal layer LC2 of the second liquid crystal cell to a P wave state. It is diffused in the X-axis direction by the second electrode E22, and then optically rotated in the third liquid crystal cell 30 to be emitted as an S wave.

[0114] Therefore, the liquid crystal light control element 100B is Figure 2A The control signal application conditions shown in the figure cause the first polarization component PL1 and the second polarization component PL2 to be optically rotated while simultaneously diffusing each polarization component PL1 and PL2 once in the X-axis direction. This results in the light from the light source being diffused and emitted in the X-axis direction as a whole. In other words, the liquid crystal light control element 100B can distribute the light emitted from the light source so that the light distribution is spread in the X-axis direction (linear distribution).

[0115] Figure 2B The following state is shown: the control signal CV is applied to the third strip electrode E12A and the fourth strip electrode E12B of the first liquid crystal unit 10, the control signal LH1 is applied to the first strip electrode E21A of the second liquid crystal unit 20, the control signal HL1 is applied to the second strip electrode E21B, the control signal CV is applied to the third strip electrode E22A and the fourth strip electrode E22B, the control signal LH1 is applied to the first strip electrode E31A of the third liquid crystal unit 30, and the control signal HL1 is applied to the second strip electrode E31B.

[0116] If inserted Figure 2BAs shown in the table, the first polarization component PL1 (S wave) of light emitted from the light source is optically rotated in each of the first and second liquid crystal cells 10 and 20 to an S-wave state. It then diffuses in the Y-axis direction via the first electrode E31 of the third liquid crystal cell 30, is optically rotated in the third liquid crystal layer LC3, and is emitted as a P-wave. Furthermore, the second polarization component PL2 (P wave) is optically rotated in the first liquid crystal cell 10 to an S-wave state. It then diffuses in the Y-axis direction via the first electrode E21 of the second liquid crystal cell 20, is optically rotated in the second liquid crystal layer LC2, and is further optically rotated in the third liquid crystal cell 30 to an S-wave state before being emitted.

[0117] Therefore, the liquid crystal light control element 100B is Figure 2B Under the control signal application conditions shown, the first polarization component PL1 and the second polarization component PL2 are optically rotated while each polarization component PL1 and PL2 is diffused once in the Y-axis direction. This diffuses the light from the light source in the Y-axis direction before emitting the light. In other words, the liquid crystal light control element 100B can distribute the light emitted from the light source so that the light distribution is spread in the Y-axis direction (linear distribution).

[0118] Figure 2C The following state is shown: a control signal LH1 is applied to the third strip electrode E12A of the first liquid crystal unit 10, a control signal HL1 is applied to the fourth strip electrode E12B, a control signal LH1 is applied to the first strip electrode E21A of the second liquid crystal unit 20, a control signal HL1 is applied to the second strip electrode E21B, a control signal LH1 is applied to the third strip electrode E22A, a control signal HL1 is applied to the fourth strip electrode E22B, a control signal LH1 is applied to the first strip electrode E31A of the third liquid crystal unit 30, and a control signal HL1 is applied to the second strip electrode E31B.

[0119] If inserted Figure 2C As shown in the table, the first polarization component PL1 (S wave) of light emitted from the light source is optically rotated into a P wave in the first liquid crystal layer LC1 of the first liquid crystal cell 10, diffused in the X-axis direction by the second electrode E12, optically rotated into an S wave in the second liquid crystal cell 20, diffused in the Y-axis direction by the first electrode E31 of the third liquid crystal cell 30, and optically rotated into a P wave in the third liquid crystal layer LC3 before being emitted. Furthermore, the second polarization component PL2 (P wave) is optically rotated into an S wave in the first liquid crystal cell 10, diffused in the Y-axis direction by the first electrode E21 of the second liquid crystal cell 20, optically rotated into a P wave in the second liquid crystal layer LC2, diffused in the X-axis direction by the second electrode E22, and optically rotated in the third liquid crystal cell 30 before being emitted as an S wave.

[0120] Therefore, the liquid crystal light control element 100B is Figure 2C The application conditions of the control signal shown in the figure rotate the first polarization component PL1 and the second polarization component PL2 while diffusing each polarization component PL1 and PL2 once in the X-axis direction and the Y-axis direction, thereby making it possible to expand the overall light distribution state of the light from the light source in both directions of the X-axis and the Y-axis to perform light distribution (circular light distribution).

[0121] Figure 2D The following state is shown: a control signal LH1 is applied to the third strip electrode E12A of the first liquid crystal unit 10, a control signal HL1 is applied to the fourth strip electrode E12B, a control signal LH2 is applied to the first strip electrode E21A of the second liquid crystal unit 20, a control signal HL2 is applied to the second strip electrode E21B, a control signal CV is applied to the third strip electrode E22A and the fourth strip electrode E22B, and a control signal CV is applied to the third strip electrode E32A and the fourth strip electrode E32B of the third liquid crystal unit 30.

[0122] If inserted Figure 2D As shown in the table, the first polarization component PL1 (S wave) of light emitted from the light source is optically rotated into a P wave in the first liquid crystal layer LC1 of the first liquid crystal cell 10, diffused in the X-axis direction by the second electrode E12, and optically rotated in each of the second and third liquid crystal cells 20 and 30, before being emitted as a P wave. Furthermore, the second polarization component PL2 (P wave) is optically rotated into an S wave in the first liquid crystal cell 10, diffused in the Y-axis direction by the first electrode E21 of the second liquid crystal cell 20, optically rotated in the second liquid crystal layer LC2, and further optically rotated in the third liquid crystal cell 30 before being emitted as an S wave.

[0123] Therefore, the liquid crystal light control element 100B is Figure 2D The control signal application conditions shown in the figure rotate the first polarization component PL1 and the second polarization component PL2, and diffuse the first polarization component PL1 once in the X-axis direction and emit it through the control signals LH1 and HL1, and diffuse the second polarization component PL2 once in the Y-axis direction and emit it through the control signals LH2 and HL2. That is, the liquid crystal light control element 100B can stretch the first polarization component PL1 in the X-axis direction and stretch the second polarization component PL2 in the Y-axis direction for the light emitted from the light source to perform cross light distribution. In this case, since the amplitudes of the control signals LH2 and HL2 applied to the first electrode E21 of the second liquid crystal unit 20 are larger than the amplitudes of the control signals LH1 and HL1, light distribution with a large diffusion (large expansion) in the Y-axis direction can be performed. It should be noted that, in Figure 2DIn the embodiment, even if the control signals LH2 and HL2 applied to the second liquid crystal cell 20 are replaced with the control signals LH1 and HL1 applied to the first liquid crystal cell 10 , the cross light distribution can be realized in the same manner.

[0124] As described above, the liquid crystal light control element 100B according to this embodiment can change the light emitted from a light source into various light distribution states using three liquid crystal cells. The liquid crystal light control element 100B according to this embodiment is composed of three liquid crystal cells, thus achieving a thinner form factor, thereby enabling a more compact lighting device.

[0125] [Third embodiment]

[0126] Figure 3A The structure of the liquid crystal light control element 100C involved in the third embodiment is shown. Compared with the liquid crystal light control element 100A involved in the first embodiment, the liquid crystal light control element 100C involved in this embodiment has the following structure: in the first liquid crystal unit 10, no electrode is provided on the first substrate S11 side, and a second electrode E12 is provided on the second substrate S12 side; in the second liquid crystal unit 20, no electrode is provided on the first substrate S21 side, and a second electrode E22 is provided on the second substrate S22 side; in the third liquid crystal unit 30, a first electrode E31 is provided on the first substrate S31 side, and a second electrode E32 is provided on the second substrate S32 side. It should be noted that, as Figure 3A As shown in the figure ALD, an alignment film is provided even on a substrate without an electrode, and its alignment direction intersects with the alignment direction of the light distribution film on a substrate with an electrode in the same unit. Figures 3B to 3D The same is true.

[0127] Figure 3A The following state is shown: the control signal CV is applied to the third strip electrode E12A and the fourth strip electrode E12B of the first liquid crystal unit 10, the control signal LH1 is applied to the third strip electrode E22A of the second liquid crystal unit 20, and the control signal HL1 is applied to the fourth strip electrode E22B; the control signal CV is applied to the first strip electrode E31A and the second strip electrode E31B of the third liquid crystal unit 30, the control signal LH1 is applied to the third strip electrode E32A, and the control signal HL1 is applied to the fourth strip electrode E32B.

[0128] If inserted Figure 3AAs shown in the table, the first polarization component PL1 (S wave) of light emitted from the light source is optically rotated in the first liquid crystal cell 10 and the second liquid crystal cell 20, respectively, to an S wave state. It is then optically rotated in the third liquid crystal layer LC3 of the third liquid crystal cell 30 to a P wave state. It is then diffused in the X-axis direction by the second electrode E32 and emitted. Furthermore, the second polarization component PL2 (P wave) is optically rotated in the first liquid crystal cell 10, then in the second liquid crystal layer LC2 of the second liquid crystal cell to a P wave state. It is then diffused in the X-axis direction by the second electrode E22, and then optically rotated in the third liquid crystal cell 30 to be emitted as an S wave.

[0129] Therefore, the liquid crystal light control element 100C is Figure 3A Under the control signal application conditions shown, the first polarization component PL1 and the second polarization component PL2 are optically rotated while each polarization component PL1 and PL2 is diffused once in the X-axis direction. This diffuses the light from the light source in the X-axis direction before emitting the light. In other words, the liquid crystal light control element 100C can distribute the light emitted from the light source so that the light distribution is spread in the X-axis direction (linear distribution).

[0130] Figure 3B The following state is shown: a control signal LH1 is applied to the third strip electrode E12A of the first liquid crystal unit 10, a control signal HL1 is applied to the fourth strip electrode E12B, a control signal CV is applied to the third strip electrode E22A and the fourth strip electrode E22B of the second liquid crystal unit 20, a control signal LH1 is applied to the first strip electrode E31A of the third liquid crystal unit 30, a control signal HL1 is applied to the second strip electrode E31B, and a control signal CV is applied to the third strip electrode E32A and the fourth strip electrode E32B.

[0131] If inserted Figure 3B As shown in the table, the first polarization component PL1 (S wave) of light emitted from the light source is optically rotated in the first liquid crystal cell 10 and the second liquid crystal cell 20, respectively, to an S wave state. It then diffuses in the Y-axis direction by the first electrode E31 of the third liquid crystal cell 30, is optically rotated in the third liquid crystal layer LC3, and is emitted as a P wave. Furthermore, the second polarization component PL2 (P wave) is optically rotated in the first liquid crystal layer LC1 of the first liquid crystal cell 10, to an S wave state, by the second electrode E12, and is diffused in the Y-axis direction by the second liquid crystal cell 20 and the third liquid crystal cell 30, respectively, to an S wave state, and is emitted.

[0132] Therefore, the liquid crystal light control element 100C is Figure 3BThe control signal application conditions shown in the figure cause the first polarization component PL1 and the second polarization component PL2 to be optically rotated while simultaneously diffusing each polarization component PL1 and PL2 once in the Y-axis direction. This results in the light from the light source being diffused and emitted in the Y-axis direction as a whole. In other words, the liquid crystal light control element 100C can distribute the light emitted from the light source so that the light distribution is spread in the Y-axis direction (linear distribution).

[0133] Figure 3C The following state is shown: a control signal LH1 is applied to the third strip electrode E12A of the first liquid crystal unit 10, a control signal HL1 is applied to the fourth strip electrode E12B, a control signal LH1 is applied to the third strip electrode E22A of the second liquid crystal unit 20, a control signal HL1 is applied to the fourth strip electrode E22B, a control signal LH1 is applied to the first strip electrode E31A of the third liquid crystal unit 30, a control signal HL1 is applied to the second strip electrode E31B, a control signal LH1 is applied to the third strip electrode E32A, and a control signal HL1 is applied to the fourth strip electrode E32B.

[0134] If inserted Figure 3C As shown in the table, the first polarization component PL1 (S wave) of light emitted from the light source is optically rotated in the first liquid crystal cell 10 and the second liquid crystal cell 20, respectively, to an S wave state. It then diffuses in the Y-axis direction via the first electrode E31 of the third liquid crystal cell 30, is optically rotated in the third liquid crystal layer LC3 to a P wave state, and is diffused in the X-axis direction via the second electrode E32 before being emitted. Furthermore, the second polarization component PL2 (P wave) is optically rotated in the first liquid crystal layer LC1 of the first liquid crystal cell 10 to an S wave state. It then diffuses in the Y-axis direction via the second electrode E12, is optically rotated in the second liquid crystal layer LC2 of the second liquid crystal cell 20 to a P wave state, diffuses in the X-axis direction via the second electrode E22, and is optically rotated in the third liquid crystal cell 30 before being emitted as an S wave.

[0135] Therefore, the liquid crystal light control element 100C is Figure 3C The control signal application conditions shown in the figure rotate the first polarization component PL1 and the second polarization component PL2 while diffusing each polarization component PL1 and PL2 once in the X-axis direction and the Y-axis direction, thereby making it possible to expand the light emitted from the light source as a whole in the X-axis direction and the Y-axis direction for light distribution (circular light distribution).

[0136] Figure 3DThe following state is shown: a control signal LH1 is applied to the third strip electrode E12A of the first liquid crystal unit 10, a control signal HL1 is applied to the fourth strip electrode E12B, a control signal CV is applied to the third strip electrode E22A and the fourth strip electrode E22B of the second liquid crystal unit 20, a control signal CV is applied to the first strip electrode E31A and the second strip electrode E31B of the third liquid crystal unit 30, a control signal LH2 is applied to the third strip electrode E32A, and a control signal HL2 is applied to the fourth strip electrode E32B.

[0137] If inserted Figure 3D As shown in the table, the first polarization component PL1 (S wave) of light emitted from the light source is optically rotated into an S wave state in each of the first liquid crystal cell 10 and the second liquid crystal cell 20. It is then optically rotated into a P wave state in the third liquid crystal layer LC3 of the third liquid crystal cell 30, diffused in the X-axis direction by the second electrode E32, and emitted. Furthermore, the second polarization component PL2 (P wave) is optically rotated into an S wave state in the first liquid crystal layer LC1 of the first liquid crystal cell 10, diffused in the Y-axis direction by the second electrode E12, and then optically rotated into an S wave state in each of the second liquid crystal cell 20 and the third liquid crystal cell 30, and emitted as an S wave.

[0138] Therefore, the liquid crystal light control element 100C is Figure 3D The control signal application conditions shown in the figure rotate the first polarization component PL1 and the second polarization component PL2, and diffuse the first polarization component PL1 once in the X-axis direction and emit it through the control signals LH2 and HL2, and diffuse the second polarization component PL2 once in the Y-axis direction and emit it through the control signals LH1 and HL1. That is, the liquid crystal light control element 100C can stretch the first polarization component PL1 in the X-axis direction and stretch the second polarization component PL2 in the Y-axis direction for the light emitted from the light source to perform cross light distribution. In this case, since the amplitudes of the control signals LH2 and HL2 applied to the second electrode E32 of the third liquid crystal unit 30 are larger than the amplitudes of the control signals LH1 and HL1, light distribution with a large diffusion (large expansion) in the X-axis direction can be performed. It should be noted that, in Figure 3D In the embodiment, even if the control signals LH2 and HL2 applied to the third liquid crystal unit 30 are replaced with the control signals LH1 and HL1 applied to the first liquid crystal unit 10 , the cross light distribution can be realized in the same manner.

[0139] As described above, the liquid crystal light control element 100C according to this embodiment can change the light emitted from a light source into various light distribution states using three liquid crystal cells. The liquid crystal light control element 100C according to this embodiment is composed of three liquid crystal cells, thus achieving a thinner form factor, thereby enabling a more compact lighting device.

[0140] [Fourth embodiment]

[0141] Figure 4A The structure of a liquid crystal light control element 100D according to the fourth embodiment is shown. This embodiment differs from the liquid crystal light control element 100C according to the third embodiment in that, in the first liquid crystal cell 10, a first electrode E11 is provided on the first substrate S11 side, but no electrode is provided on the second substrate S12 side. In the second liquid crystal cell 20, a first electrode E21 is provided on the first substrate S21 side, but no electrode is provided on the second substrate S22 side. The structure of the third liquid crystal cell 30 is the same as that of the third embodiment.

[0142] Figure 4A The following state is shown: a control signal LH1 is applied to the first strip electrode E11A of the first liquid crystal unit 10, a control signal HL1 is applied to the second strip electrode E11B, a control signal CV is applied to the first strip electrode E21A and the second strip electrode E21B of the second liquid crystal unit 20, a control signal CV is applied to the first strip electrode E31A and the second strip electrode E31B of the third liquid crystal unit 30, a control signal LH1 is applied to the third strip electrode E32A, and a control signal HL1 is applied to the fourth strip electrode E32B.

[0143] If inserted Figure 4A As shown in the table, the first polarization component PL1 (S wave) of light emitted from the light source is optically rotated in the first liquid crystal cell 10 and the second liquid crystal cell 20, respectively, to an S wave state. It is then optically rotated in the third liquid crystal layer LC3 of the third liquid crystal cell 30 to a P wave state. It is then diffused in the X-axis direction by the second electrode E32 and emitted. Furthermore, the second polarization component PL2 (P wave) is diffused in the X-axis direction by the first electrode E11 of the first liquid crystal cell 10, optically rotated in the first liquid crystal layer LC1 to an S wave state, and then optically rotated in the second liquid crystal cell 20 and the third liquid crystal cell 30, respectively, to be emitted as an S wave.

[0144] Therefore, the liquid crystal light control element 100D is Figure 4A The control signal application conditions shown in the figure cause the first polarization component PL1 and the second polarization component PL2 to be optically rotated while simultaneously diffusing each polarization component PL1 and PL2 once in the X-axis direction. This results in the light from the light source being diffused and emitted in the X-axis direction as a whole. In other words, the liquid crystal light control element 100D can distribute the light emitted from the light source so that the light distribution is spread in the X-axis direction (linear distribution).

[0145] Figure 4BThe following state is shown: a control signal CV is applied to the first strip electrode E11A and the second strip electrode E11B of the first liquid crystal unit 10, a control signal LH1 is applied to the first strip electrode E21A of the second liquid crystal unit 20, a control signal HL1 is applied to the second strip electrode E21B, a control signal LH1 is applied to the first strip electrode E31A of the third liquid crystal unit 30, a control signal HL1 is applied to the second strip electrode E31B, and a control signal CV is applied to the third strip electrode E32A and the fourth strip electrode E32B.

[0146] If inserted Figure 4B As shown in the table, the first polarization component PL1 (S wave) of light emitted from the light source is optically rotated in the first liquid crystal cell 10 and the second liquid crystal cell 20, respectively, to an S wave state. It then diffuses in the Y-axis direction via the first electrode E31 of the third liquid crystal cell 30, and is optically rotated in the third liquid crystal layer LC3 before being emitted as a P wave. Furthermore, the second polarization component PL2 (P wave) is optically rotated in the first liquid crystal cell 10 to an S wave state. It then diffuses in the Y-axis direction via the first electrode E21 of the second liquid crystal cell 20, and is optically rotated in the second liquid crystal layer LC2 to a P wave state. It is then optically rotated in the third liquid crystal cell 30 to an S wave state before being emitted.

[0147] Therefore, the liquid crystal light control element 100D is Figure 4B Under the control signal application conditions shown, the first polarization component PL1 and the second polarization component PL2 are optically rotated while each polarization component PL1 and PL2 is diffused once in the Y-axis direction. This diffuses the light from the light source in the Y-axis direction before emitting the light. In other words, the liquid crystal light control element 100D can distribute the light emitted from the light source so that the light distribution is spread in the Y-axis direction (linear distribution).

[0148] Figure 4C The following state is shown: a control signal LH1 is applied to the first strip electrode E11A of the first liquid crystal unit 10, a control signal HL1 is applied to the second strip electrode E11B, a control signal LH1 is applied to the first strip electrode E21A of the second liquid crystal unit 20, a control signal HL1 is applied to the second strip electrode E21B, a control signal LH1 is applied to the first strip electrode E31A of the third liquid crystal unit 30, a control signal HL1 is applied to the second strip electrode E31B, a control signal LH1 is applied to the third strip electrode E32A, and a control signal HL1 is applied to the fourth strip electrode E32B.

[0149] If inserted Figure 4CAs shown in the table, the first polarization component PL1 (S wave) of light emitted from the light source is optically rotated in the first liquid crystal cell 10 and the second liquid crystal cell 20, respectively, to an S wave state. It then diffuses in the Y-axis direction by the first electrode E31 of the third liquid crystal cell 30, is optically rotated in the third liquid crystal layer LC3 to a P wave state, and is then diffused in the X-axis direction by the second electrode E32 before being emitted. Furthermore, the second polarization component PL2 (P wave) diffuses in the X-axis direction by the first electrode E11 of the first liquid crystal cell 10, is optically rotated in the first liquid crystal layer LC1 to an S wave state, diffuses in the Y-axis direction by the first electrode E21 of the second liquid crystal cell 20, is optically rotated in the second liquid crystal layer LC2 to a P wave state, and is then optically rotated in the third liquid crystal cell 30 before being emitted as an S wave.

[0150] Therefore, the liquid crystal light control element 100D is Figure 4C The application conditions of the control signal shown in the figure rotate the first polarization component PL1 and the second polarization component PL2 while diffusing each polarization component PL1 and PL2 once in the X-axis direction and the Y-axis direction, thereby making it possible to expand the overall light distribution state of the light emitted from the light source in the X-axis direction and the Y-axis direction for light distribution (circular light distribution).

[0151] Figure 4D The following state is shown: a control signal LH1 is applied to the first strip electrode E11A of the first liquid crystal unit 10, a control signal HL1 is applied to the second strip electrode E11B, a control signal CV is applied to the first strip electrode E21A and the second strip electrode E21B of the second liquid crystal unit 20, a control signal LH2 is applied to the first strip electrode E31A of the third liquid crystal unit 30, a control signal HL2 is applied to the second strip electrode E31B, and a control signal CV is applied to the third strip electrode E32A and the fourth strip electrode E32B.

[0152] If inserted Figure 4D As shown in the table, the first polarization component PL1 (S wave) of light emitted from the light source is optically rotated in the first liquid crystal cell 10 and the second liquid crystal cell 20, becoming an S wave. It then diffuses in the Y-axis direction by the first electrode E31 of the third liquid crystal cell 30, is optically rotated in the third liquid crystal layer LC3, and is emitted as a P wave. Furthermore, the second polarization component PL2 (P wave) diffuses in the X-axis direction by the first electrode E11 of the first liquid crystal cell 10, is optically rotated in the first liquid crystal layer LC1, becoming an S wave. It then diffuses in the second liquid crystal cell 20 and the third liquid crystal cell 30, and is emitted as an S wave.

[0153] Therefore, the liquid crystal light control element 100D is Figure 4DThe control signal application conditions shown in the figure rotate the first polarization component PL1 and the second polarization component PL2 while the first polarization component PL1 is diffused once in the Y-axis direction and emitted by the control signals LH2 and HL2, and the second polarization component PL2 is diffused once in the X-axis direction and emitted by the control signals LH1 and HL1. That is, the liquid crystal light control element 100D can perform cross light distribution by stretching the first polarization component PL1 in the Y-axis direction and stretching the second polarization component PL2 in the X-axis direction for the light emitted from the light source. The first polarization component PL1 is diffused once in the Y-axis direction while being rotated, and the second polarization component PL2 is diffused once in the X-axis direction while being rotated. In this case, since the amplitudes of the control signals LH2 and HL2 applied to the first electrode E31 of the third liquid crystal unit 30 are larger than the amplitudes of the control signals LH1 and HL1, light distribution with a large diffusion (large expansion) in the Y-axis direction can be performed. It should be noted that in Figure 4D In the embodiment, even if the control signals LH2 and HL2 applied to the third liquid crystal unit 30 are replaced with the control signals LH1 and HL1 applied to the first liquid crystal unit 10 , the cross light distribution can be realized in the same manner.

[0154] As described above, the liquid crystal light control element 100D according to this embodiment can change the light emitted from a light source into various light distribution states using three liquid crystal cells. The liquid crystal light control element 100D according to this embodiment is composed of three liquid crystal cells, thus achieving a thinner form factor, thereby enabling a more compact lighting device.

[0155] [Fifth embodiment]

[0156] This embodiment shows the light distribution characteristics of the liquid crystal light control element 100B shown in the second embodiment. Figure 5A This is a photograph obtained by photographing the projection surface of illumination light when no control signal is applied to the liquid crystal light control element 100B. Figure 5B As shown in reference Figure 2C A photograph of the projection surface when control signals LH1 and HL1 are applied to all electrodes of each liquid crystal cell as described above. The cell gap and electrode pitch of the liquid crystal light control element 100B used for measurement are as follows. In addition, the control signals LH1 and HL1 driving the liquid crystal light control element 100B are VH1 = 15V and VL1 = -15V (see Figure 15A ).

[0157]

[0158] like Figure 5A As shown in FIG, when no control signal is applied to the liquid crystal light control element 100B, the intensity distribution of the illumination light directly reflects the light intensity distribution of the light source. Figure 5BAs shown, it can be seen that when the control signals LH1 and HL1 are applied, the illumination light is diffused in the vertical and horizontal directions.

[0159] Figure 6 The luminance-angle characteristics of the liquid crystal light control element 100B are shown. Figure 6 The horizontal axis of the graph shown represents polar angle, and the vertical axis represents brightness. Figure 6 The graph shows the characteristics of the liquid crystal light control element 100B and the characteristics of a liquid crystal light control element composed of four liquid crystal cells as a reference example. The brightness shown on the vertical axis of the graph is a normalized value, with the brightness of the reference example element at a polar angle of 0 degrees being 100.

[0160] It should be noted that the “polar angle” refers to the angle formed by the normal direction of the main surface of the liquid crystal light control element and the direction of travel of the outgoing light. Figure 6 As shown in the inset, measurements were performed while rotating the liquid crystal light control element 100 and light source 202 relative to the detector 301. As shown in the figure, the angle θ at which the main surface of the liquid crystal light control element 100 is tilted relative to the state in which the main surface of the liquid crystal light control element 100 faces the detector 301 (the detector 301 is arranged in the normal direction of the main surface of the liquid crystal light control element 100) corresponds to the polar angle. Specifically, when the main surface of the liquid crystal light control element 100 faces the detector 301, the polar angle is 0 degrees. As the liquid crystal light control element 100 is tilted, the polar angle θ increases. Therefore, when the liquid crystal light control element 100 faces the detector 301 (polar angle 0 degrees), the frontal luminance is observed. By examining how the luminance changes with varying polar angles, the light distribution characteristics of the liquid crystal light control element 100 can be understood. Therefore, smaller changes in luminance with respect to polar angles indicate that the light emitted from the light source 202 can be distributed over a wider angle.

[0161] like Figure 6 As shown in the graph, the liquid crystal light control element 100B exhibits higher overall brightness than the reference element (an element with four liquid crystal cells). Furthermore, while the reference element (an element with four liquid crystal cells) has a light distribution angle of 53 degrees, the liquid crystal light control element 100B achieves a comparable light distribution angle of 52 degrees. Note that the light distribution angle refers to the angle (polar angle) at which the brightness is reduced to half of the brightness at a polar angle of 0 degrees.

[0162] These results demonstrate that reducing the number of liquid crystal cells increases brightness, and that a wide light distribution angle can be maintained by employing an electrode structure similar to that of the liquid crystal light control element 100B. Furthermore, using such a liquid crystal light control element allows for miniaturization of lighting devices without degrading light distribution characteristics.

[0163] [Sixth embodiment]

[0164] This embodiment illustrates the light distribution characteristics of the liquid crystal light control element 100B described in the second embodiment when the cell gap of the liquid crystal cells is varied. The cell gap of the liquid crystal light control element 100B used for measurement is 55 μm for the second liquid crystal cell 20, while the cell gaps of the first and third liquid crystal cells 10 and 30 are 15 μm. Specifically, the cell gap D2 of the second liquid crystal cell 20, which has electrodes on both the first and second substrates S21 and S22, is larger than the cell gap D1 of the first and third liquid crystal cells 10 and 30, which have electrodes on only one of the first and second substrates S11, S31, S12, and S32 (D2 > D1). In this embodiment, D2 > 3 × D1, but it suffices to satisfy at least D2 > D1, more preferably D2 > 2 × D1, and even more preferably D2 > 3 × D1. On the other hand, there are inherent limits to the cell gap for stable control of liquid crystal molecules. Therefore, D2 is preferably set to ≤ 100 μm, and for this reason, D2 ≤ 6 × D1 is even more preferable. Furthermore, the control signals LH1 and HL1 for driving the liquid crystal light control element 100B are VH1 = 15V and VL1 = -15V.

[0165]

[0166] Figure 7 The luminance-angle characteristics of the liquid crystal light control element 100B having the structure shown in Table 2 are shown. Figure 7 As shown in the graph, it can be seen that the characteristics of the liquid crystal light control element 100B according to this embodiment are different from those shown in the fifth embodiment (see Figure 6 ) is higher. In addition, the light distribution angle is 52 degrees, which is equivalent to the light distribution angle of the reference example shown in the fifth embodiment. Figure 7 The characteristics shown in the graph indicate that similar characteristics can be achieved even if the cell gap is changed for each liquid crystal cell constituting the liquid crystal light control element 100B. This configuration, in which the cell gap size of the liquid crystal cells constituting the liquid crystal light control element is changed for each liquid crystal cell, can also be adopted in the first, third, and fourth embodiments. In this case, it is of course possible to adopt a configuration in which the cell gap of a liquid crystal cell having electrodes on both substrates is larger than the cell gap of a liquid crystal cell having electrodes on only one substrate, or to adopt a configuration in which the cell gap size of the liquid crystal cell having electrodes on only the one substrate is also different.

[0167] As shown in this embodiment, by reducing the cell gap of a liquid crystal cell in which electrodes are provided only on one side of a pair of substrates, it is possible to increase transmittance and reduce the amount of liquid crystal material used. Furthermore, by using such a liquid crystal light control element, it is possible to achieve miniaturization of the lighting device and increase brightness even with the same power consumption.

[0168] [Seventh embodiment]

[0169] This embodiment shows light distribution characteristics when the electrode width and electrode pitch of the liquid crystal cell are changed in the liquid crystal light control element 100B shown in the second embodiment. Figure 8 The structure of a liquid crystal light control element 100B used for evaluation is shown. Figure 8 In the illustrated liquid crystal light control element 100B, the cell gap D2 of the second liquid crystal cell 20 is larger than the cell gap D1 of the first and third liquid crystal cells 10 and 30. Furthermore, the electrode width W2 and electrode gap P2 of the second liquid crystal cell 20 are in the relationship W1>W2 and P1<P2 relative to the electrode width W1 and electrode gap P1 of the first and third liquid crystal cells 10 and 30, respectively. It should be noted that the relationship between the cell gap D1, electrode width W1, and electrode gap P1 of the first and third liquid crystal cells 10 and 30 is designed so that the value of W1+P1 is approximately equal to D1. Similarly, the relationship between the cell gap D2 of the second liquid crystal cell 20, electrode width W2, and electrode gap P2 is designed so that the value of W2+P2 is approximately equal to D2. As a specific example, as shown in Table 3, the electrode width / electrode gap of the first and third liquid crystal cells 10 and 30 is 8μm / 8μm, and the electrode width / electrode gap of the second liquid crystal cell 20 is 4μm / 24μm. The first and third liquid crystal cells 10 and 30 have electrodes on only one substrate. Therefore, unlike the second liquid crystal cell 20, the electric field formed by the electrodes on one substrate does not affect the electric field formed on the other substrate. In these so-called single-electrode liquid crystal cells, a cell gap smaller than twice the electrode spacing can be used. On the other hand, in liquid crystal cells with electrodes on both substrates, as in the second liquid crystal cell, a cell gap larger than twice the electrode spacing is still preferred.

[0170]

[0171] Figure 9 The luminance-angle characteristics of the liquid crystal light control element 100B having the structure shown in Table 3 are shown. Figure 9 As shown in the graph, it can be seen that the characteristics of the liquid crystal light control element 100B according to this embodiment are different from those shown in the fifth embodiment (see Figure 7), the brightness is higher, and the area with small changes in brightness (the curve in the graph is flat) is expanded in the area with small extreme angles. In addition, the light distribution angle is 47 degrees, which is sufficient for practical use.

[0172] In addition, in this embodiment, it is also possible to adopt a structure in which the electrode width of the second liquid crystal cell 20 is set to the same size as the electrodes provided in the first liquid crystal cell 10 and the third liquid crystal cell 30 .

[0173] As shown in this embodiment, light distribution characteristics can be changed by changing the electrode width and electrode spacing of the liquid crystal cell. In particular, by narrowing the electrode width and increasing the electrode spacing of the liquid crystal cell with a large cell gap, the area with high and uniform brightness can be expanded.

[0174] Note that the structure of changing the cell gap, electrode width, and electrode interval of the liquid crystal cell as described in this embodiment is also applicable to the liquid crystal light control elements described in the first, third, and fourth embodiments.

[0175] The various structures of the liquid crystal light control element illustrated as an embodiment of the present invention may be appropriately combined as long as they do not conflict with each other. In addition, liquid crystal light control elements obtained by those skilled in the art by appropriately adding, deleting, or modifying the design of components based on the liquid crystal light control element disclosed in this specification and the accompanying drawings, or by adding, omitting, or modifying the conditions of the liquid crystal light control element, as long as they meet the main purpose of the present invention, are within the scope of the present invention.

[0176] Even if there are other effects that are different from the effects brought about by the scheme of the embodiment disclosed in this specification, if they are effects that are clear based on the description of this specification or effects that can be easily predicted by those skilled in the art, they are of course understood to be effects brought about by the present invention.

[0177] Description of Reference Numerals

[0178] 10: First liquid crystal unit, 20: Second liquid crystal unit, 30: Third liquid crystal unit, 100, 100A, 100B, 100C, 100D: Liquid crystal light control element, 200: Illumination device, 202: Light source, AL11: First alignment film, AL12: Second alignment film, ALD1, ALD2: Alignment direction, E11, E21, E31: First electrode, E11A, E21A, E31A: First strip electrode, E11B, E21B, E31B: Second strip electrode, E12, E22, E32: Second electrode, E12A, E22A, E23A: Second Three strip electrodes, E12B, E22B, E23B: fourth strip electrodes, F1: first flexible wiring substrate, F2: second flexible wiring substrate, F3: third flexible wiring substrate, LC1: first liquid crystal layer, LC2: second liquid crystal layer, LC3: third liquid crystal layer, LCM: liquid crystal molecule, PE11: first power supply line, PE12: second power supply line, PE13: third power supply line, PE14: fourth power supply line, S11: first substrate, S12: second substrate, T11: first connecting terminal, T12: second connecting terminal, T13: third connecting terminal, T14: fourth connecting terminal.

Claims

1. A liquid crystal light control element, characterized in that: The liquid crystal light control element is composed of a first liquid crystal cell, a second liquid crystal cell, and a third liquid crystal cell, wherein the first liquid crystal cell, the second liquid crystal cell, and the third liquid crystal cell respectively have a first substrate arranged on the light incident side, a second substrate arranged on the light emitting side, and a liquid crystal layer between the first substrate and the second substrate. The first liquid crystal cell, the second liquid crystal cell, and the third liquid crystal cell are arranged to overlap in an emission direction of light emitted from a light source. The first liquid crystal unit has a first electrode, which is provided on only one of the first substrate and the second substrate and is composed of a first strip electrode and a second strip electrode. The second liquid crystal unit has: a first electrode, disposed on the first substrate, and consisting of a first strip electrode and a second strip electrode; and The second electrode is provided on the second substrate and is composed of a third strip electrode and a fourth strip electrode. The third liquid crystal cell includes a first electrode provided on only one of the first substrate and the second substrate and composed of a first strip-shaped electrode and a second strip-shaped electrode.

2. The liquid crystal light control element according to claim 1, wherein The first liquid crystal unit, the second liquid crystal unit, and the third liquid crystal unit are sequentially arranged in an emitting direction of light emitted from the light source. The first electrode of the first liquid crystal unit is disposed on the first substrate of the first liquid crystal unit. The first electrode of the third liquid crystal unit is disposed on the second substrate of the third liquid crystal unit.

3. The liquid crystal light control element according to claim 2, wherein: The direction in which the first strip electrode and the second strip electrode of the second liquid crystal unit extend intersects with the direction in which the third strip electrode and the fourth strip electrode of the second liquid crystal unit extend. The direction in which the first strip electrode and the second strip electrode of the first liquid crystal cell extend is the same as the direction in which the first strip electrode and the second strip electrode of the second liquid crystal cell extend. The first strip-shaped electrode and the second strip-shaped electrode of the third liquid crystal unit extend in the same direction as the third strip-shaped electrode and the fourth strip-shaped electrode of the second liquid crystal unit extend.

4. The liquid crystal light control element according to claim 1, wherein The first liquid crystal unit, the second liquid crystal unit, and the third liquid crystal unit are sequentially arranged in an emitting direction of light emitted from the light source. The first electrode of the first liquid crystal unit is disposed on the second substrate of the first liquid crystal unit, The first electrode of the third liquid crystal unit is disposed on the first substrate of the third liquid crystal unit.

5. The liquid crystal light control element according to claim 4, wherein The direction in which the first strip electrode and the second strip electrode of the second liquid crystal unit extend intersects with the direction in which the third strip electrode and the fourth strip electrode of the second liquid crystal unit extend. The direction in which the first strip electrodes and the second strip electrodes of the first liquid crystal cell extend intersects with the direction in which the first strip electrodes and the second strip electrodes of the second liquid crystal cell extend. The direction in which the first strip-shaped electrodes and the second strip-shaped electrodes of the third liquid crystal cell extend intersects with the direction in which the third strip-shaped electrodes and the fourth strip-shaped electrodes of the second liquid crystal cell extend.

6. The liquid crystal light control element according to claim 1, wherein The first liquid crystal unit, the third liquid crystal unit, and the second liquid crystal unit are sequentially arranged in an emitting direction of light emitted from the light source. The first electrode of the first liquid crystal unit is disposed on the second substrate of the first liquid crystal unit, The first electrode of the third liquid crystal unit is disposed on the second substrate of the third liquid crystal unit.

7. The liquid crystal light control element according to claim 6, wherein: The direction in which the first strip electrode and the second strip electrode of the second liquid crystal unit extend intersects with the direction in which the third strip electrode and the fourth strip electrode of the second liquid crystal unit extend. The direction in which the first strip electrode and the second strip electrode of the first liquid crystal cell extend is the same as the direction in which the first strip electrode and the second strip electrode of the second liquid crystal cell extend. The first strip-shaped electrode and the second strip-shaped electrode of the third liquid crystal unit extend in the same direction as the third strip-shaped electrode and the fourth strip-shaped electrode of the second liquid crystal unit extend.

8. The liquid crystal light control element according to claim 1, wherein The first liquid crystal unit, the third liquid crystal unit, and the second liquid crystal unit are sequentially arranged in an emitting direction of light emitted from the light source. The first electrode of the first liquid crystal unit is disposed on the first substrate of the first liquid crystal unit. The first electrode of the third liquid crystal unit is disposed on the first substrate of the third liquid crystal unit.

9. The liquid crystal light control element according to claim 8, wherein The direction in which the first strip electrode and the second strip electrode of the second liquid crystal unit extend intersects with the direction in which the third strip electrode and the fourth strip electrode of the second liquid crystal unit extend. The direction in which the first strip electrode and the second strip electrode of the first liquid crystal cell extend intersects with the direction in which the first strip electrode and the second strip electrode of the second liquid crystal cell extend. The direction in which the first strip-shaped electrodes and the second strip-shaped electrodes of the third liquid crystal cell extend intersects with the direction in which the third strip-shaped electrodes and the fourth strip-shaped electrodes of the second liquid crystal cell extend.

10. The liquid crystal light control element according to claim 1, wherein A cell gap of the second liquid crystal cell is larger than cell gaps of the first liquid crystal cell and the third liquid crystal cell.

11. The liquid crystal light control element according to claim 10, wherein The interval between the first strip electrode and the second strip electrode and the interval between the third strip electrode and the fourth strip electrode of the second liquid crystal cell are larger than the interval between the first strip electrode and the second strip electrode of the first liquid crystal cell and the interval between the first strip electrode and the second strip electrode of the third liquid crystal cell.

12. The liquid crystal light control element according to claim 1, wherein The first liquid crystal cell, the second liquid crystal cell, and the third liquid crystal cell are provided with a first alignment film on the first substrate side and a second alignment film on the second substrate side. An alignment direction of the first alignment film intersects with an alignment direction of the second alignment film.

13. The liquid crystal light control element according to claim 1, wherein The liquid crystal layer is twisted nematic liquid crystal.

14. A lighting device, characterized in that: The lighting device includes the liquid crystal light control element according to any one of claims 1 to 13 and a light source, wherein the liquid crystal light control element is provided on an optical path of light emitted from the light source.

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