Liquid crystal light control element and lighting device

Abstract

A liquid crystal light control element has a plurality of liquid crystal cells each including: a first substrate and a second substrate opposed to the first substrate; a first electrode and a second electrode provided to at least one of the first substrate and the second substrate and having a strip pattern; a first alignment film provided to the first substrate and a second alignment film provided to the second substrate; and a liquid crystal layer between the first substrate and the second substrate. The plurality of liquid crystal cells are arranged in a superposed manner, the strip patterns of the first electrode and the second electrode are arranged alternately, and a voltage is applied to form a lateral electric field between the first electrode and the second electrode. An orientation direction of the first alignment film is set to cross an extension direction of the strip pattern, and an orientation direction of the second alignment film is set to cross the orientation direction of the first alignment film.

Description

Technical Field

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

[0002] Illumination devices equipped with liquid crystal lenses are disclosed. For example, an illumination device is disclosed in which two liquid crystal lenses are overlapped and the degree of overlap of the strip-shaped transparent electrodes provided on each liquid crystal lens is adjusted to eliminate uneven light illumination (see Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2010-230887 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] Illumination devices using liquid crystal lenses can control the diffusion of light in both the horizontal and vertical directions. However, a problem arises as to the inability to precisely control the light distribution in the polar angle direction. In other words, existing illumination devices using liquid crystal lenses cannot achieve precise control over the diffused light distribution.

[0008] One embodiment of the present invention aims to provide a liquid crystal light control element capable of precisely controlling the intensity distribution of light emitted from a light source. Furthermore, another embodiment of the present invention aims to provide an illumination device equipped with a liquid crystal light control element capable of precisely controlling the intensity distribution of light emitted from a light source.

[0009] Solutions for solving technical problems

[0010] An embodiment of the present invention relates to a liquid crystal light control element having a plurality of liquid crystal cells, each of the plurality of liquid crystal cells comprising: a first substrate and a second substrate opposite to the first substrate; a first electrode and a second electrode disposed on at least one of the first substrate and the second substrate and having a strip pattern; a first alignment film disposed on the first substrate and a second alignment film disposed on the second substrate; and a liquid crystal layer between the first substrate and the second substrate. The plurality of liquid crystal cells are arranged in an overlapping manner, the strip patterns of the first electrode and the second electrode are alternately arranged, and a voltage is applied to form a lateral electric field between the first electrode and the second electrode. The alignment direction of the first alignment film is configured to intersect the extension direction of the strip pattern, and the alignment direction of the second alignment film is configured to intersect the alignment direction of the first alignment film. Attached Figure Description

[0011] Figure 1 The structure of the liquid crystal cell constituting a liquid crystal light control element according to an embodiment of the present invention is shown in a perspective view.

[0012] Figure 2A This is a top view showing the electrodes disposed on the first substrate of the liquid crystal cell constituting a liquid crystal light control element according to an embodiment of the present invention.

[0013] Figure 2B This is a top view showing the electrodes disposed on the second substrate of the liquid crystal cell constituting a liquid crystal light control element according to an embodiment of the present invention.

[0014] Figure 3 An example of the cross-sectional structure of a liquid crystal cell constituting a liquid crystal light control element according to an embodiment of the present invention is shown.

[0015] Figure 4A This diagram illustrates the operation of a liquid crystal cell constituting a liquid crystal light control element according to an embodiment of the present invention, showing the orientation state of liquid crystal molecules when no voltage is applied.

[0016] Figure 4B This diagram illustrates the operation of a liquid crystal cell constituting a liquid crystal light control element according to an embodiment of the present invention, showing the orientation state of the liquid crystal molecules when a voltage is applied.

[0017] Figure 4C This diagram illustrates the operation of a liquid crystal cell constituting a liquid crystal light control element according to an embodiment of the present invention, showing the orientation state of the liquid crystal molecules when a voltage is applied.

[0018] Figure 5A This diagram illustrates the operation of a liquid crystal cell constituting a liquid crystal light control element according to an embodiment of the present invention.

[0019] Figure 5B This diagram illustrates a liquid crystal cell constituting a liquid crystal light control element according to an embodiment of the present invention, showing an example of the distribution of polarized waves emitted from the liquid crystal cell.

[0020] Figure 6 The structure (first structure) and diffusion state of the liquid crystal light control element according to the first embodiment of the present invention are shown.

[0021] Figure 7 The waveform of the control signal applied to the liquid crystal cell constituting a liquid crystal light control element according to an embodiment of the present invention is shown.

[0022] Figure 8The structure (a variation of the first structure) and diffusion state of the liquid crystal light control element according to the first embodiment of the present invention are shown.

[0023] Figure 9 The structure (a variation of the first structure) and diffusion state of the liquid crystal light control element according to the first embodiment of the present invention are shown.

[0024] Figure 10 The structure (second structure) and diffusion state of the liquid crystal light control element according to the first embodiment of the present invention are shown.

[0025] Figure 11 The structure and diffusion state of the liquid crystal light control element involved in the reference example are shown.

[0026] Figure 12A A graph showing the brightness-angle characteristics of the liquid crystal light control element is used as a characteristic of the liquid crystal light control element according to the first embodiment of the present invention.

[0027] Figure 12B The distribution of emitted light is shown as a characteristic of the liquid crystal light control element according to the first embodiment of the present invention.

[0028] Figure 12C The distribution of emitted light is shown as a characteristic of the liquid crystal light control element according to the first embodiment of the present invention.

[0029] Figure 12D The distribution of emitted light is shown as a characteristic of the liquid crystal light control element according to the first embodiment of the present invention.

[0030] Figure 12E The distribution of emitted light is shown as a characteristic of the liquid crystal light control element according to the first embodiment of the present invention.

[0031] Figure 13 The structure (third structure) and diffusion state of the liquid crystal light control element according to the second embodiment of the present invention are shown.

[0032] Figure 14 The structure (fourth structure) and diffusion state of the liquid crystal light control element according to the second embodiment of the present invention are shown.

[0033] Figure 15 The structure and diffusion state of the liquid crystal light control element involved in the reference example are shown.

[0034] Figure 16 A graph showing the brightness-angle characteristics of the liquid crystal light control element according to the second embodiment of the present invention is provided.

[0035] Figure 17The structure (fifth structure) of the liquid crystal light control element according to the third embodiment of the present invention and the diffusion state are shown.

[0036] Figure 18 The structure (fifth structure) of the liquid crystal light control element according to the third embodiment of the present invention and the diffusion state are shown.

[0037] Figure 19 The structure and diffusion state of the liquid crystal light control element involved in the reference example are shown.

[0038] Figure 20 A graph showing the brightness-angle characteristics of the liquid crystal light control element according to the third embodiment of the present invention is provided.

[0039] Figure 21 A perspective view of a lighting device according to an embodiment of the present invention is shown. Detailed Implementation

[0040] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the present invention can be implemented in many different ways and is not limited to the description of the embodiments illustrated below. For clarity, the drawings sometimes only schematically show the width, thickness, shape, etc. of various parts compared to the actual embodiments; however, these are merely examples and not intended to limit the interpretation of the present invention. Furthermore, in this specification and the drawings, elements that are the same as those described in previously appeared drawings are sometimes labeled with the same reference numerals (or reference numerals such as a, b, etc. are used after the numbers), appropriately omitting detailed descriptions. Moreover, the designations "first," "second," etc., for each element are used for ease of distinction and do not imply anything beyond their scope unless otherwise specified.

[0041] In this specification, the phrase "above (or below) other components or regions" means, unless otherwise specified, not only "directly above (or directly below)" other components or regions, but also "above (or below)" other components or regions, that is, it also includes situations where other structural elements are contained between "above (or below)" other components or regions.

[0042] In this specification, "optical rotation" refers to the phenomenon that linearly polarized components rotate their polarization axis when passing through a liquid crystal layer.

[0043] In this specification, the "orientation direction" of an alignment film refers to the direction in which liquid crystal molecules are oriented when an alignment constraint force is applied to the alignment film (e.g., a rubbing process) to orient the liquid crystal molecules on the alignment film. When the alignment film is subjected to a rubbing process, the orientation direction of the alignment film is typically the rubbing direction.

[0044] In this specification, the "direction of extension" of a strip pattern refers to the direction in which the long side of a pattern having a short side (width) and a long side (length) extends when viewed from above. Furthermore, a strip pattern includes rectangular patterns when viewed from above, as well as patterns that bend or curve at least once along their long side.

[0045] In this specification, "polar angle" refers to the angle between the normal direction of the main surface of the liquid crystal panel and the direction of the emitted light.

[0046] Figure 1 This is a perspective view showing the structure of the first liquid crystal cell 10. The first liquid crystal cell 10 includes a first substrate S11, a second substrate S12, and a first liquid crystal layer LC1 between the first substrate S11 and the second substrate S12. A first electrode E11 and a first alignment film AL11 are disposed on the first substrate S11, and a second electrode E12 and a second alignment film AL12 are disposed on the second substrate S12. The first alignment film AL11 covers the first electrode E11, and the second alignment film AL12 covers the second electrode E12. The first electrode E11 and the first alignment film AL11 are disposed on the first liquid crystal layer LC1 side of the first substrate S11, and the second electrode E12 and the second alignment film AL12 are disposed on the first liquid crystal layer LC1 side of the second substrate S12. The first electrode E11 and the second electrode E12 are opposite to each other across the first liquid crystal layer LC1.

[0047] The first electrode E11 includes a first strip electrode E11A and a second strip electrode E11B having a strip pattern (or a comb-like pattern). The second electrode E12 includes a third strip electrode E12A and a fourth strip electrode E12B having a strip pattern (or a comb-like pattern). A plurality of first strip electrodes E11A and second strip electrodes E11B are alternately disposed on the insulating surface of the first substrate S11, and a plurality of third strip electrodes E12A and fourth strip electrodes E12B are alternately disposed on the insulating surface of the second substrate S12.

[0048] Figure 1 For illustration, the X, Y, and Z axis directions are shown. For the first liquid crystal cell 10, the extension directions of the first strip electrode E11A and the plurality of second strip electrodes E11B are configured parallel to the X-axis direction, and the extension directions of the third strip electrode E12A and the plurality of fourth strip electrodes E12B are configured parallel to the Y-axis direction. The third strip electrode E12A and the fourth strip electrode E12B are arranged intersecting the first strip electrode E11A and the second strip electrode E11B. The extension directions of the first strip electrode E11A and the second strip electrode E11B intersect the extension directions of the third strip electrode E12A and the fourth strip electrode E12B, for example, within a range of 90 ± 10 degrees, preferably orthogonal (90 degrees).

[0049] The first alignment film AL11 and the second alignment film AL12 have alignment restraint forces that are substantially parallel to the main plane of each substrate. The alignment direction of the first alignment film AL11 is set to intersect the extension directions of the first strip electrode E11A and the second strip electrode E11B (Y-axis direction), and the alignment direction of the second alignment film AL12 is set to intersect the extension directions of the third strip electrode E12A and the fourth strip electrode E12B (X-axis direction). The angle between the alignment directions of the first alignment film AL11 and the second alignment film AL12 and the extension directions of the strip electrodes can be set within the range of 90±10 degrees.

[0050] The first liquid crystal layer LC1, for example, uses twisted nematic (TN) liquid crystal. When no voltage is applied to the first electrode E11 and the second electrode E12, the long axis of the liquid crystal molecules LCM in the first liquid crystal layer LC1, influenced by the alignment restraint forces of the first alignment film AL11 and the second alignment film AL12, is aligned in a direction parallel to the alignment direction. The alignment direction of the first alignment film AL11 and the alignment direction of the second alignment film AL12 are intersecting (orthogonal), therefore, the alignment direction gradually changes in such a way that the long axis of the liquid crystal molecules LCM is twisted by 90 degrees from the first substrate S11 to the second substrate S12. Furthermore, Figure 1 Although not shown in the figure, a spacer for keeping the spacing constant may be provided between the first substrate S11 and the second substrate S12.

[0051] Compared to Figure 1 The initial alignment state of the liquid crystal molecule (LCM) shown is altered by applying a voltage to create a potential difference between the first strip electrode E11A and the second strip electrode E11B, thereby changing the alignment state of the LCM on the first substrate S11 side. Furthermore, by applying a voltage to create a potential difference between the third strip electrode E12A and the fourth strip electrode E12B, the alignment state of the LCM on the second substrate S12 side is altered.

[0052] Figure 2A A top view of the first substrate S11 is shown. Figure 2B A top view of the second substrate S12 is shown.

[0053] like Figure 2AAs shown, a first electrode E11 is provided on a first substrate S11. The first electrode E11 includes a plurality of first strip electrodes E11A and a plurality of second strip electrodes E11B. The plurality of first strip electrodes E11A and the plurality of second strip electrodes E11B have strip patterns. The strip patterns of the plurality of first strip electrodes E11A and the strip patterns of the plurality of second strip electrodes E11B are spaced apart at predetermined intervals in a direction intersecting the extension direction and are alternately arranged.

[0054] Multiple first strip electrodes E11A are connected to a first power supply line PE11, and multiple second strip electrodes E11B are connected to a second power supply line PE12. The first power supply line PE11 is connected to a first connection terminal T11, and the second power supply line PE12 is connected to a second connection terminal T12. The first connection terminal T11 and the second connection terminal T12 are disposed along one side of the end of the first substrate S11. On the first substrate S11, a third connection terminal T13 is disposed adjacent to the first connection terminal T11, and a fourth connection terminal T14 is disposed 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 disposed 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 disposed at a predetermined position within the surface of the first substrate S11.

[0055] Multiple first strip electrodes E11A are connected to a first power supply line PE11 and are subjected to the same voltage. Multiple second strip electrodes E11B are connected to a second power supply line PE12 and are subjected to the same voltage. If different voltages are applied to the multiple first strip electrodes E11A and the multiple second strip electrodes E11B respectively, an electric field is generated between the two electrodes due to the potential difference. That is, a transverse electric field is generated through the multiple first strip electrodes E11A and the multiple second strip electrodes E11B.

[0056] like Figure 2B As shown, a second electrode E12 is provided on the second substrate S12. The second electrode E12 includes a plurality of third strip electrodes E12A and a plurality of fourth strip electrodes E12B. The plurality of third strip electrodes E12A and the plurality of fourth strip electrodes E12B have strip patterns. The strip patterns of the plurality of third strip electrodes E12A and the plurality of fourth strip electrodes E12B are spaced apart at a predetermined interval and alternately arranged in a direction intersecting the extension direction. The third strip electrodes E12A and the fourth strip electrodes E12B are arranged at an inclination of 90 ± 10 degrees relative to the extension direction of the first strip electrode E11A and the second strip electrode E11B.

[0057] Multiple third strip electrodes E12A are connected to the third power supply line PE13, and multiple fourth strip electrodes E12B are connected to the fourth power supply line PE14. The third power supply line PE13 is connected to the third power supply terminal PT13, and the fourth power supply line PE14 is connected to the fourth power supply terminal PT14. The third power supply terminal PT13 is located at the position corresponding to the first power supply terminal PT11 on the first substrate S11, and the fourth power supply terminal PT14 is located at the position corresponding to the second power supply terminal PT12 on the first substrate S11.

[0058] Multiple third strip electrodes E12A are connected to the third power supply line PE13 and are subjected to the same voltage. Multiple fourth strip electrodes E12B are connected to the fourth power supply line PE14 and are subjected to the same voltage. If different voltages are applied to the multiple third strip electrodes E12A and the multiple fourth strip electrodes E12B respectively, an electric field is generated between the two electrodes due to the potential difference. That is, a transverse electric field is generated through the multiple third strip electrodes E12A and the multiple fourth strip electrodes E12B.

[0059] The connection terminals T11 to T14 disposed on the first substrate S11 are connected to the flexible wiring substrate. The first power supply terminal PT11 and the third power supply terminal PT13 of the first liquid crystal cell 10 are electrically connected by a conductive material, and the second power supply terminal PT12 and the fourth power supply terminal PT14 are electrically connected by a conductive material.

[0060] Figure 3 A cross-sectional view of the first liquid crystal cell 10 is shown. Figure 3 The cross-sectional structure of the first liquid crystal cell 10 shown is illustrated. Figure 2A The first substrate S11 shown and Figure 2B The cross-sectional structure corresponding to the A1-A2 line of the second substrate S12 shown.

[0061] The first liquid crystal cell 10 has an effective area AA through which incident light passes. A first electrode E11 and a second electrode E12 are disposed in the effective area AA. The first substrate S11 and the second substrate S12 are bonded together by a sealing member SE disposed on the outside of the effective area AA. The first liquid crystal layer LC1 is sealed between the first substrate S11 and the second substrate S12 by the sealing member SE.

[0062] The first power supply terminal PT11 has a continuous structure from the fifth power supply line PE15 and is disposed on the outside of the seal SE. The third power supply terminal PT13 has a continuous structure from the third power supply line PE13 and is disposed on the outside of the seal SE.

[0063] The first power supply terminal PT11 and the third power supply terminal PT13 are opposite each other and are configured to be opposite each other in the region outside the seal SE. A first conductive component CP11 is disposed between the first power supply terminal PT11 and the third power supply terminal PT13, and electrically connects the two. The first conductive component CP11 can be formed of a conductive paste material, such as silver paste or carbon paste. Furthermore, Figure 3 Although not shown, the second power supply terminal PT12 and the fourth power supply terminal PT14 are also electrically connected through conductive components.

[0064] The first substrate S11 and the second substrate S12 are light-transmitting substrates, such as glass substrates or resin substrates. The first electrode E11 and the second electrode E12 are transparent electrodes formed of transparent conductive materials such as indium tin oxide (ITO) and indium zinc oxide (IZO). The power supply lines (first power supply line PE11, second power supply line PE12, third power supply line PE13, fourth power supply line PE14, fifth power supply line PE15, and sixth power supply line PE16), the connection terminals (first connection terminal T11, second connection terminal T12, third connection terminal T13, and fourth connection terminal T14), and the power supply terminals (first power supply terminal PT11, second power supply terminal PT12, third power supply terminal PT13, and fourth power supply terminal PT14) are formed of metallic materials such as aluminum, titanium, molybdenum, and tungsten. Alternatively, the power supply lines (first power supply line PE11, second power supply line PE12, third power supply line PE13, fourth power supply line PE14, fifth power supply line PE15, and sixth power supply line PE16) can also be formed of the same transparent conductive film as the first electrode E11 and the second electrode E12. Of course, it is also possible to use a structure in which either or both of the first electrode E11 and the second electrode E12 are formed of a metallic material.

[0065] Figure 4A A partial perspective view of the first liquid crystal cell 10 is shown. Figure 4A The arrangement of the first strip electrode E11A, the second strip electrode E11B, the third strip electrode E12A, the fourth strip electrode E12B, and the first liquid crystal layer LC1 is shown. Figure 4B as well as Figure 4C A cross-sectional schematic diagram of the first liquid crystal cell 10 is shown. Figure 4B as well as Figure 4C The diagram shows views from side A and side B, respectively. Figure 4A A cross-sectional schematic diagram of the first liquid crystal cell 10 shown. Additionally, Figure 4B as well as Figure 4C The orientation treatment direction of the first orientation film AL11 is different from that of the second orientation film AL12.

[0066] like Figure 4AAs shown, the first strip electrode E11A and the second strip electrode E11B are arranged with a center-to-center distance W, and the third strip electrode E12A and the fourth strip electrode E12B are similarly arranged with a center-to-center distance W. Figure 4A As shown, if the width of the first strip electrode E11A is set as "a", and the interval from the end of the first strip electrode E11A to the end of the second strip electrode E11B is set as "b", then the distance W between the centers has the relationship W = a + b.

[0067] like Figure 4B as well as Figure 4C As shown, the first substrate S11 and the second substrate S12 are arranged opposite each other with a gap D. The gap D is the distance between the substrates, but it is substantially equivalent to the thickness of the first liquid crystal layer LC1. In fact, the first substrate S11 is provided with a first strip electrode E11A and a first alignment film AL11, and the second substrate S12 is provided with a third strip electrode E12A and a second alignment film AL12, etc. However, the thickness of these electrodes and alignment films is small enough compared to the size of the gap D. Therefore, the thickness of the first liquid crystal layer LC1 is substantially the same as the gap D.

[0068] Preferably, the spacing D, which is equivalent to the thickness of the first liquid crystal layer LC1, is the same as or greater than the center-to-center distance W of the strip electrodes (D≥W). Preferably, the spacing D has a length that is at least one time the center-to-center distance W. For example, it is preferable that the spacing D, which is equivalent to the thickness of the first liquid crystal layer LC1, is at least twice the center-to-center distance W of the strip electrodes. For example, when the width of the first strip electrode E11A is 5 μm, the width a of both the first strip electrode E11A and the second strip electrode E11B is 5 μm, and the spacing b from the end of the first strip electrode E11A to the end of the second strip electrode E11B is 5 μm, the center-to-center distance W of the strip electrodes is 10 μm. In contrast, it is preferable that the spacing D, which is equivalent to the thickness of the first liquid crystal layer LC1, has a length of 10 μm or more.

[0069] The center-to-center distance W between the strip electrodes is related to the spacing D, which corresponds to the thickness of the first liquid crystal layer LC1, thereby suppressing the mutual interference of the electric fields 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.

[0070] It is known that the refractive index of liquid crystals changes according to their orientation. For example... Figure 1As shown, in the off-state where no electric field is applied to the first liquid crystal layer LC1, the long axis of the liquid crystal molecules is horizontally aligned on the surface of the substrate, and is oriented with a 90-degree twist from the first substrate S11 side to the second substrate S12 side. At this time, the first liquid crystal layer LC1 has a uniform refractive index distribution. When light is incident on the first liquid crystal cell 10, the polarization component of the incident light is redirected by the twisting of the liquid crystal molecules LCM. Hereinafter, the effect of such a liquid crystal layer will be referred to as optical rotation. In this case, the incident light passes through the first liquid crystal layer LC1 without refraction (or scattering) while simultaneously undergoing optical rotation.

[0071] On the other hand, such as Figure 4C As shown, if the liquid crystal molecule (LCM) is in a conducting (ON) state, generating an electric field between the first strip electrode E11A and the second strip electrode E11B, then the long axis of the LCM is aligned along the electric field (in the case where the liquid crystal has positive dielectric anisotropy). As a result, as... Figure 4C As shown, in the first liquid crystal layer LC1, there are regions in which liquid crystal molecules LCM stand upright above the first strip electrode E11A and the second strip electrode E11B, regions in which the liquid crystal molecules LCM are tilted and oriented along the distribution of the electric field between the first strip electrode E11A and the second strip electrode E11B, and regions in which the initial orientation state is maintained in the region away from the first substrate S11.

[0072] Similarly, as Figure 4B As shown, if the electric field between the third strip electrode E12A and the fourth strip electrode E12B is generated in the ON state, then in the first liquid crystal layer LC1, there are regions in which liquid crystal molecules LCM stand upright above the third strip electrode E12A and the fourth strip electrode E12B, regions in which the liquid crystal molecules LCM are tilted and oriented along the distribution of the electric field between the third strip electrode E12A and the fourth strip electrode E12B, and regions in which the initial orientation state is maintained in the region away from the second substrate S12.

[0073] like Figure 4B as well as Figure 4C As shown, if an electric field is generated between the first strip electrode E11A and the second strip electrode E11B, and between the third strip electrode E12A and the fourth strip electrode E12B, a region is formed in which the long axis of the liquid crystal molecules (LCM) is oriented in a convex arc shape along the direction of the electric field. That is, as... Figure 4A as well as Figure 4B As shown, when the initial orientation of the liquid crystal molecule LCM is the same as the direction of the transverse electric field generated between the first strip electrode E11A and the second strip electrode E11B, the liquid crystal molecule LCM is tilted (with an inclination) in the normal direction of the surface of the first substrate S11 according to the intensity distribution of the electric field.

[0074] At this time, as Figure 4B as well as Figure 4C As shown, the spacing D, which corresponds to the thickness of the first liquid crystal layer LC1, is sufficiently large. Therefore, the electric field on the first substrate S11 side has little effect on the orientation of the liquid crystal molecules on the second substrate S12 side. Conversely, the same applies.

[0075] A transverse electric field is formed through strip electrodes, thereby creating a convex arc-shaped dielectric constant distribution in the first liquid crystal layer LC1. The polarization component of light incident on the first liquid crystal layer LC1, parallel to the initial orientation of the liquid crystal molecules LCM, diffuses radially according to this dielectric constant distribution. Figure 4B as well as Figure 4C As shown, because the orientation directions of the liquid crystal molecules (LCM) on the first substrate S11 side and the second substrate S12 side are intersected (or orthogonal), light diffuses in different directions on the first substrate S11 side and the second substrate S12 side, respectively.

[0076] Thus, when light passes through the first liquid crystal cell 10, depending on the formation of the electric field in the first liquid crystal layer LC1, a portion of the polarization component diffuses and passes through, while the remaining polarization component remains unchanged and passes through the first liquid crystal LC1.

[0077] Figure 5A A first liquid crystal cell 10 is shown, in which the strip electrode of the first electrode E11 extends along the X-axis direction and the strip electrode of the second electrode E12 extends along the Y-axis direction. It is in the following states: a voltage is applied to the first electrode E11 to generate a transverse electric field (Y-axis direction) between the first strip electrode E11A and the second strip electrode E11B; a voltage is applied to the second electrode E12 to generate a transverse electric field (X-axis direction) between the third strip electrode E12A and the fourth strip electrode E12B.

[0078] Figure 5A This illustrates a state in which, under such a bias condition, light comprising a first polarization component PL1 parallel to the X-axis and a second polarization component PL2 parallel to the Y-axis is incident from the first substrate S11 and emitted from the second substrate S12 in the first liquid crystal cell 10. Here, the first polarization component PL1 is assumed to correspond to an S-wave, and the second polarization component PL2 is assumed to correspond to a P-wave.

[0079] In the first liquid crystal cell 10, the long axis of the liquid crystal molecules (LCM) on the first substrate S11 side faces the Y-axis direction, and the long axis of the liquid crystal molecules (LCM) on the second substrate S12 side faces the X-axis direction. The light of the first polarization component PL1 incident from the first substrate S11 side passes through the first substrate S12 side as is because its polarization direction intersects the long axis of the liquid crystal molecules (LCM). The light of the second polarization component PL2, whose polarization direction is parallel to the long axis of the liquid crystal molecules (LCM), diffuses in the Y-axis direction due to the arc-shaped refractive index distribution formed according to the orientation of the liquid crystal molecules (LCM). The light of the first polarization component PL1 enters from the first substrate S11 side to the second substrate S12 side through the first liquid crystal layer LC1 and rotates by 90 degrees. At this time, its polarization direction becomes orthogonal to the orientation direction of the long axis of the liquid crystal molecules on the second substrate S12 side, thus passing through the second substrate S12 as is. On the other hand, the second polarization component PL2 enters from the first substrate S11 side to the second substrate S12 side through the first liquid crystal layer LC1 and rotates at 90 degrees. At this time, the polarization direction becomes parallel to the orientation direction of the long axis of the liquid crystal molecules on the second substrate S12 side. Therefore, it diffuses in the X-axis direction and is emitted from the second substrate S12.

[0080] Thus, if light is incident upon Figure 5A In the first liquid crystal cell 10 shown, the first polarization component PL1 (S-wave) does not diffuse, while the second polarization component PL2 (P-wave) diffuses in the X-axis and Y-axis directions.

[0081] Figure 5B The distribution of the S-wave (emitted P-wave) is shown. The first polarization component PL1 (S-wave), as described above, should theoretically not diffuse, but... Figure 5B The distribution confirms that the first polarization component PL1 (S-wave) is scarce and diffuses in the Y-axis direction. This indicates that the second polarization component PL2 (P-wave), which diffuses in the Y-axis direction on the first substrate S11 side, is not a completely optically rotated component remaining in the first liquid crystal layer LC1.

[0082] Thus, if no polarized components remain in the liquid crystal cell, it is known that the distribution of emitted light is affected. The liquid crystal light control element 102 illustrated in the following embodiment has a structure in which the distribution of emitted light can be precisely controlled by arranging multiple liquid crystal cells in an overlapping manner.

[0083] [First Implementation]

[0084] This embodiment illustrates an example where the liquid crystal light control element is composed of four liquid crystal cells. Each liquid crystal cell has a liquid crystal layer between a pair of substrates, and at least one substrate has a liquid crystal layer. Figure 1 The strip electrode shown.

[0085] 1-1. First Structure

[0086] Figure 6 The diagram shows the electrode configuration in each liquid crystal cell of the liquid crystal light control element 102 according to the first structure, and the state when light incident on the liquid crystal light control element 102 passes through each liquid crystal cell. The liquid crystal light control element 102 according to the first structure has a first liquid crystal cell 10, a second liquid crystal cell 20, a third liquid crystal cell 30, and a fourth liquid crystal cell 40 superimposed from the light incident side to the light emission side. Figure 6 For illustration, the X-axis, Y-axis, and Z-axis are shown. In the following description, the X-axis direction refers to the direction along the X-axis, the Y-axis direction refers to the direction along the Y-axis, and the Z-axis direction refers to the direction along the Z-axis.

[0087] The first structure involves a liquid crystal light control element 102 in which a first liquid crystal unit 10, a second liquid crystal unit 20, a third liquid crystal unit 30, and a fourth liquid crystal unit 40 are stacked along the Z-axis. In practice, the liquid crystal light control element 102 is configured such that the liquid crystal units are closely connected, but... Figure 6 For illustration, the unfolded state of each liquid crystal cell is shown.

[0088] The first liquid crystal unit 10 has the following structure: a first electrode (a first strip electrode E11A and a second strip electrode E11B) is provided on a first substrate S11, a second electrode E12 (a planar electrode, also called a flat or full-surface electrode) is provided on a second substrate S12, and a first liquid crystal layer LC1 is provided between the first substrate S11 and the second substrate S12. The first strip electrode E11A and the second strip electrode E11B are configured to extend along the Y-axis direction. Furthermore, Figure 6 The alignment film is omitted, but its orientation direction is indicated by arrows. Specifically, the first alignment film AL11 (not shown) on the first substrate S11 side is oriented towards the X-axis, and the second alignment film AL12 (not shown) on the second substrate S12 side is oriented towards the Y-axis. The angle between the orientation directions of the first alignment film AL11 and the second alignment film AL12 is preferably 90 ± 10 degrees, more preferably 90 degrees (orthogonal).

[0089] The second liquid crystal unit 20 includes a first substrate S21 and a second substrate S22, a first electrode E21 (a first strip electrode E21A and a second strip electrode E21B) and a second electrode E22 (a planar electrode, also called a flat or full-surface electrode), and a second liquid crystal layer LC2 between the first substrate S21 and the second substrate S22. The second liquid crystal unit 20 has the same structure as the first liquid crystal unit 10. That is, the second liquid crystal unit 20 is configured such that the extending directions of the first strip electrode E21A and the second strip electrode E21B extend along the Y-axis direction.

[0090] The third liquid crystal unit 30 includes a first substrate S31 and a second substrate S32, a first electrode E31 (a first strip electrode E31A and a second strip electrode E31B) and a second electrode E32 (a planar electrode, also called a flat or full-surface electrode), and a third liquid crystal layer LC3 between the first substrate S31 and the second substrate S32. The third liquid crystal unit 30 has the same structure as the first liquid crystal unit 10, but is configured such that the extension directions of the first strip electrode E31A and the second strip electrode E31B extend along the X-axis direction. Correspondingly, the alignment direction of the alignment film is oriented towards the Y-axis direction on the first substrate S31 side and towards the X-axis direction on the second substrate S32 side.

[0091] The fourth liquid crystal unit 40 includes a first substrate S41 and a second substrate S42, a first electrode E41 (a first strip electrode E41A and a second strip electrode E41B) and a second electrode E42 (a planar electrode, also called a flat or full-surface electrode), and a fourth liquid crystal layer LC4 between the first substrate S41 and the second substrate S42. The fourth liquid crystal unit 40 has the same structure as the third liquid crystal unit 30. That is, the fourth liquid crystal unit 40 is configured such that the extending directions of the first strip electrode E41A and the second strip electrode E41B extend along the X-axis direction. Furthermore, the alignment direction of the alignment film is oriented towards the Y-axis direction on the first substrate S41 side and towards the X-axis direction on the second substrate S42 side.

[0092] As described above, for the liquid crystal light control element 102 involved in the first structure, the liquid crystals of the first liquid crystal unit 10 and the second liquid crystal unit 20 have the same orientation direction, and the extension directions of the strip electrodes (E11A, E11B, E21A, E21B) in the first electrodes E11 and E21 are in the same direction. Furthermore, the liquid crystals of the third liquid crystal unit 30 and the fourth liquid crystal unit 40 have the same orientation direction, and the extension directions of the strip electrodes (E31A, E31B, E41A, E41B) in the first electrodes E31 and E41 are in the same direction. Furthermore, the extension directions of the strip electrodes (E11A, E11B, E21A, E21B) of the first electrodes E11 and E21 in the first liquid crystal unit 10 and the second liquid crystal unit 20 intersect the extension directions of the strip electrodes (E31A, E31B, E41A, E41B) of the first electrodes E31 and E41 in the third liquid crystal unit 30 and the fourth liquid crystal unit 40 at an angle of 90 degrees.

[0093] Figure 6The diagram shows the electrode configuration in the first liquid crystal cell 10, the second liquid crystal cell 20, the third liquid crystal cell 30, and the fourth liquid crystal cell 40, the alignment direction based on the alignment film (arrows), and the initial alignment of the liquid crystal molecules. The liquid crystal layer is formed of positive liquid crystal, and in the initial state where no control signal is input to each liquid crystal cell, the long axis direction of the liquid crystal is aligned in a direction intersecting the strip electrode (orthogonal to the direction). That is, the orientation direction of the alignment film (first alignment film) on the first substrate S11, S21, S31, S41 side configured as the first liquid crystal unit 10, the second liquid crystal unit 20, the third liquid crystal unit 30, and the fourth liquid crystal unit 40 intersects the extension direction of the first electrode E11, E21, E31, E41 with the strip pattern, and the orientation direction of the alignment film (second alignment film) on the second substrate S12, S22, S32, S42 side intersects the orientation direction of the alignment film (first alignment film) on the first substrate S11, S21, S31, S41 side.

[0094] according to Figure 6 In the configuration shown, the alignment films (not shown) on the first substrate S11 and S21 sides of the first liquid crystal cell 10 and the second liquid crystal cell 20 are aligned in a direction parallel to the X-axis, and the alignment films (not shown) on the second substrate S12 and S22 sides are aligned in a direction parallel to the Y-axis. The extension direction of the strip pattern of the first electrode E11 and E21 of the first liquid crystal cell 10 and the second liquid crystal cell 20 is parallel to the Y-axis, and the second electrode E12 and E22 are planar (also called flat or full-surface) electrodes that extend at least in the effective area (the area through which incident light passes, the same applies below). Furthermore, the alignment films (not shown) on the first substrate S31 and S41 sides of the third liquid crystal cell 30 and the fourth liquid crystal cell 40 are aligned in a direction parallel to the Y-axis, and the alignment films (not shown) on the second substrate S32 and S42 sides are aligned in a direction parallel to the X-axis. The strip patterns of the first electrodes E31 and E41 of the third liquid crystal unit 30 and the fourth liquid crystal unit 40 extend in a direction parallel to the X-axis direction, and the second electrodes E32 and E42 become planar (also called flat or full-surface) electrodes that extend at least in the effective area. The alignment direction of the alignment film intersects at a 90-degree angle on the first substrate side and the second substrate side of each liquid crystal unit according to the definitions of the X-axis direction and the Y-axis direction, but the angle of intersection can be set within the range of 90 ± 10 degrees.

[0095] In the following description, the direction with the same polarization direction as the first polarization component PL1 is designated as the X-axis direction, and the direction with the same polarization direction as the second polarization component PL2 is designated as the Y-axis direction. For example, the first polarization component PL1 is an S-wave, and the second polarization component PL2 is a P-wave. Furthermore, Figure 6The table shows "Diffusion (X)" indicating that the polarization component diffuses in the X-axis direction, and "Diffusion (Y)" indicating that the polarization component diffuses in the Y-axis direction.

[0096] Figure 6 The electrodes to which a control signal is applied and which form a transverse electric field are represented by cross-sectional lines. Furthermore, Figure 6 The table inserted below uses terms such as transmission, optical rotation, and diffusion to describe the state of the polarization components of light containing the first polarization component PL1 and the second polarization component PL2 as they pass through the first electrode, the liquid crystal layer, and the second electrode of each liquid crystal cell. Here, "transmission" means that the polarization component passes through unchanged without diffusion or optical rotation. "Diffusion" means that the polarization component diffuses and transmits due to the influence of the refractive index distribution of the liquid crystal molecules. Therefore, in the table, for example, "transmission" at the first electrode indicates that the aforementioned "transmission" phenomenon occurs near the first electrode of the liquid crystal layer. Furthermore, in the following explanation, "optical rotation" in the liquid crystal layer means that the polarization direction of the polarization component changes by 90 degrees as it moves from the first substrate side to the second substrate side within the liquid crystal layer.

[0097] The liquid crystal light control element 102 involved in the first structure is provided with a first liquid crystal unit 10, a second liquid crystal unit 20, a third liquid crystal unit 30, and a fourth liquid crystal unit 40 arranged sequentially from the light incident side to the light emission side. The light incident on the liquid crystal light control element 102 includes a first polarization component PL1 and a second polarization component PL2 orthogonal to the first polarization component PL1.

[0098] like Figure 6 As shown, the first electrode E11 of the first liquid crystal cell 10 and the first electrode E21 of the second liquid crystal cell 20 are configured such that the extension direction of the strip electrodes is the same, enabling the first polarization component PL1 to diffuse in the X-axis direction in the first liquid crystal cell 10 and the second polarization component PL2 to diffuse in the X-axis direction in the second liquid crystal cell 20. Furthermore, the second electrode E32 of the third liquid crystal cell 30 and the second electrode E42 of the fourth liquid crystal cell 40 are configured such that the extension direction of the second polarization component PL2 is the same, enabling the second polarization component PL2 to diffuse in the Y-axis direction in the third liquid crystal cell 30 and the first polarization component PL1 to diffuse in the Y-axis direction in the fourth liquid crystal cell 40.

[0099] In order to control the polarization state and diffusion state of the light incident on the liquid crystal light control element 102, a control signal is input to each liquid crystal cell. Figure 7 This shows an example of the waveform of the control signal applied to the electrodes of each liquid crystal cell. Each liquid crystal cell has an input... Figure 7The control signal shown is any one of the control signals A, B, or E. In control signals A and B, VL1 refers to a low-level voltage, and VH1 refers to a high-level voltage. For example, VL1 is 0V or -15V, and VH1 is 30V (relative to 0V) or 15V (relative to -15V). Control signal A is synchronized with control signal B; when control signal A is at the VL1 level, control signal B is at the VH1 level, and if control signal A changes to the VH1 level, control signal B changes to the VL1 level. The period of control signals A and B is approximately 15–100Hz. On the other hand, control signal E is a constant voltage signal; for example, control signal E is the intermediate voltage between VL1 and VH1, where VE = 0V when VL1 = -15V and VH1 = +15V.

[0100] Light is incident on the liquid crystal light control element 102 from a light source not shown in the figure. Preferably, the light irradiated from the light source is collimated light. By selecting the control signal applied to each liquid crystal cell, the liquid crystal light control element 102 can control the distribution (intensity distribution) of the light distribution pattern emitted from the light source not shown in the figure. Specifically, it can control the distribution of the polar angle direction of the illumination light.

[0101] Table 1 shows the... Figure 6 The control signals applied to each liquid crystal cell of the liquid crystal light control element 102 shown are as follows. Additionally, the control signals A, B, and E shown in Table 1 are... Figure 7 The control signals shown correspond to those shown.

[0102] [Table 1]

[0103]

[0104] As shown in Table 1, control signals are input to each liquid crystal cell of the liquid crystal light control element 102. Control signal A is input to the first strip electrode E11A of the first liquid crystal cell 10, control signal B is input to the second strip electrode E11B, and control signal E is input to the second electrode E12, generating a lateral electric field only on the side of the first electrode E11. As shown in Table 1, the same applies to the second liquid crystal cell 20, the third liquid crystal cell 30, and the fourth liquid crystal cell 40. That is, for… Figure 6 In the case of the liquid crystal light control element 102 shown, control signals A and B are applied to the first electrode of each liquid crystal cell, and control signal E is applied to the second electrode, thereby generating a lateral electric field only on the first substrate side.

[0105] When the liquid crystal light control element 102 operates, control signals as shown in Table 1 are input to each strip electrode of each liquid crystal cell. If the control signals shown in Table 1 are input to the first liquid crystal cell 10, the second liquid crystal cell 20, the third liquid crystal cell 30, and the fourth liquid crystal cell 40, then each liquid crystal cell will... Figure 4CAs shown, the liquid crystal molecules on the first substrate side are affected by the lateral electric field and their orientation changes.

[0106] Next, the operation of the liquid crystal light control element 102 will be explained by describing the effect of the incident light on each liquid crystal cell. Here, the incident light is assumed to contain two polarization components: a first polarization component PL1 and a second polarization component PL2. The first polarization component PL1 and the second polarization component PL2 are linearly polarized components, having either s-polarization or p-polarization. These polarization states can be switched from s-polarization to p-polarization or from p-polarization to s-polarization by rotating the light within the liquid crystal layer. Furthermore, in the immediate state immediately preceding the incident light onto the liquid crystal light control element 102, the first polarization component PL1 is assumed to be s-polarized and the second polarization component PL2 is assumed to be p-polarized.

[0107] Figure 6 In this study, we focus on the first polarization component PL1. The first polarization component PL1 is incident on the first liquid crystal cell 10 in an s-polarized state. The polarization direction of the first polarization component PL1 (s-polarized) is along the X-axis, parallel to the orientation direction of the long axis of the liquid crystal molecules on the first substrate S11 side of the first liquid crystal layer LC1. On the first substrate S11 side, the liquid crystal molecules are oriented under the influence of the lateral electric field generated by the first electrode E11, forming an arc-shaped refractive index distribution in the first liquid crystal layer LC1. The first polarization component PL1 (s-polarized) incident from the first substrate S11 onto the first liquid crystal layer LC1 diffuses in the X-axis direction under the influence of the arc-shaped refractive index distribution of the first liquid crystal layer LC1. As the first polarization component PL1 (s-polarized) moves from the first substrate S11 side towards the second substrate S12 side in the first liquid crystal layer LC1, it rotates by 90 degrees due to the torsional orientation of the liquid crystal molecules. Thus, the first polarization component PL1 transitions from s-polarization to p-polarization. The second electrode E12 is a planar electrode (also called a flat or full-surface electrode) and its entire surface is at a constant potential. Therefore, the liquid crystal molecules on the second substrate S12 side of the first liquid crystal layer LC1 do not form an arc-shaped refractive index distribution. Consequently, the first polarization component PL1 (p-polarized) does not diffuse and remains as is, exiting from the second substrate S12. Thus, the first polarization component PL1 is incident on the first liquid crystal cell 10 in an s-polarized state, diffuses in the X-axis direction, rotates 90 degrees, and exits from the first liquid crystal cell 10 in a p-polarized state.

[0108] The first polarization component PL1, passing through the first liquid crystal cell 10, is incident on the second liquid crystal cell 20 in a p-polarized state. The polarization direction of the first polarization component PL1 (p-polarized) is along the Y-axis and intersects the orientation direction of the long axis of the liquid crystal molecules on the first substrate S21 side of the second liquid crystal layer LC2. On the first substrate S21 side, the liquid crystal molecules are oriented under the influence of the lateral electric field generated by the first electrode E21, forming an arc-shaped refractive index distribution in the second liquid crystal layer LC2. However, the first polarization component PL1 (p-polarized) does not diffuse and remains oriented towards the second substrate S22. As the first polarization component PL1 (p-polarized) moves from the first substrate S21 side to the second substrate S22 side in the second liquid crystal layer LC2, it rotates by 90 degrees due to the torsional orientation of the liquid crystal molecules. Thus, the first polarization component PL1 changes from p-polarized to s-polarized. The second electrode E22 is a planar electrode (also called a flat or full-surface electrode), and the entire surface is at a constant potential. Therefore, the liquid crystal molecules on the second substrate S22 side of the second liquid crystal layer LC2 do not form an arc-shaped refractive index distribution. Consequently, the first polarization component PL1 (s-polarization) does not diffuse and is emitted from the second substrate S22 as is. Thus, the first polarization component PL1 is incident into the second liquid crystal cell 20 in a p-polarized state, does not diffuse, and is emitted from the second liquid crystal cell 20 in a 90-degree polarized state.

[0109] The first polarization component PL1 of the second liquid crystal cell 20 is incident on the third liquid crystal cell 30 in an s-polarized state. In the third liquid crystal cell 30, the extension direction of the strip electrodes (E31A, E31B) of the first electrode E31 is orthogonal to the extension direction of the strip electrodes (E11A, E11B, E21A, E21B) of the first electrodes E11 and E21 of the first liquid crystal cell 10 and the second liquid crystal cell 20. The polarization direction of the first polarization component PL1 (s-polarization) is along the X-axis and is perpendicular to the orientation direction of the long axis of the liquid crystal molecules on the first substrate S31 side of the third liquid crystal layer LC3. On the first substrate S31 side, the liquid crystal molecules are oriented under the influence of the lateral electric field generated by the first electrode E31, and an arc-shaped refractive index distribution is formed in the third liquid crystal layer LC3, but the first polarization component PL1 (s-polarization) does not diffuse and remains oriented towards the second substrate S32. The first polarization component PL1 (s-polarized) rotates 90 degrees in the third liquid crystal layer LC3 as it moves from the first substrate S31 side towards the second substrate S32 side due to the torsional orientation of the liquid crystal molecules. Thus, the first polarization component PL1 transitions from s-polarization to p-polarization. The second electrode E32 is a planar electrode (also called a flat plate or full-surface electrode) with a constant potential across its entire surface. Therefore, the liquid crystal molecules on the second substrate S32 side of the third liquid crystal layer LC3 do not form an arc-shaped refractive index distribution. Consequently, the first polarization component PL1 (p-polarized) does not diffuse and exits from the second substrate S32 as is. Thus, the first polarization component PL1, incident on the third liquid crystal cell 30 in an s-polarized state, does not diffuse, rotates 90 degrees, and exits from the third liquid crystal cell 30 in a p-polarized state.

[0110] The first polarization component PL1 of the third liquid crystal cell 30 is incident on the fourth liquid crystal cell 40 in a p-polarized state. The first electrode E41 of the fourth liquid crystal cell 40 faces the same direction as the first electrode E31 of the third liquid crystal cell 30. Therefore, the orientation direction of the long axis of the liquid crystal molecules on the first substrate S41 side of the fourth liquid crystal cell 40 is also the same as that of the third liquid crystal cell 30. The polarization direction of the first polarization component PL1 (p-polarized) is along the Y-axis direction and is parallel to the orientation direction of the long axis of the liquid crystal molecules on the first substrate S41 side of the fourth liquid crystal layer LC4. On the first substrate S41 side, the liquid crystal molecules are oriented under the influence of the transverse electric field generated by the first electrode E41, forming an arc-shaped refractive index distribution in the fourth liquid crystal layer LC4. The first polarization component PL1 (p-polarized) incident from the first substrate S41 to the fourth liquid crystal layer LC4 is diffused in the Y-axis direction under the influence of the arc-shaped refractive index distribution of the fourth liquid crystal layer LC4. The first polarization component PL1 (p-polarized) rotates 90 degrees in the fourth liquid crystal layer LC4 as it moves from the first substrate S41 side towards the second substrate S42 side due to the torsional orientation of the liquid crystal molecules. Thus, the first polarization component PL1 transitions from p-polarized to s-polarized. The second electrode E42 is a planar electrode (also called a flat plate or full-surface electrode), and its entire surface has a constant potential. Therefore, the liquid crystal molecules on the second substrate S42 side of the fourth liquid crystal layer LC4 do not form an arc-shaped refractive index distribution. Consequently, the first polarization component PL1 (s-polarized) does not diffuse and exits from the second substrate S42 as is. Thus, the first polarization component PL1, in a p-polarized state, is incident on the fourth liquid crystal cell 40, diffuses in the Y-axis direction, rotates 90 degrees, and exits from the fourth liquid crystal cell 40 in an s-polarized state.

[0111] Thus, the first polarization component PL1 incident on the liquid crystal light control element 102 undergoes one diffusion in the X-axis direction and one diffusion in the Y-axis direction during the period from incident on the first liquid crystal cell 10 to being emitted from the fourth liquid crystal cell 40. It is incident in an s-polarized state and rotated four times at an angle of 90 degrees, thereby being emitted in an s-polarized state.

[0112] Next, we focus on the second polarization component PL2. The second polarization component PL2 is incident on the first liquid crystal cell 10 in a p-polarized state. The polarization direction of the second polarization component PL2 (p-polarized) is along the Y-axis and intersects the orientation direction of the long axis of the liquid crystal molecules on the first substrate S11 side of the first liquid crystal layer LC1. On the first substrate S11 side, an arc-shaped refractive index distribution is formed in the first liquid crystal layer LC1, but the second polarization component PL2 (p-polarized) does not diffuse and remains oriented towards the second substrate S12. As the first polarization component PL1 (p-polarized) moves from the first substrate S11 side to the second substrate S12 side in the first liquid crystal layer LC1, it rotates by 90 degrees due to the torsional orientation of the liquid crystal molecules. Thus, the first polarization component PL1 transitions from p-polarized to s-polarized. On the second substrate S12 side, the planar (also called flat or full-surface) second electrode E12 has a constant potential. Therefore, no arc-shaped refractive index distribution is formed in the first liquid crystal layer LC1, and the second polarization component PL2 (s-polarized) does not diffuse and is emitted from the second substrate S12. Thus, the second polarization component PL2 is incident on the first liquid crystal cell 10 in a p-polarized state, does not diffuse, and is emitted from the first liquid crystal cell 10 in a s-polarized state with 90-degree optical rotation.

[0113] The second polarization component PL2, passing through the first liquid crystal cell 10, is incident on the second liquid crystal cell 20 in an s-polarized state. The polarization direction of the second polarization component PL2 (s-polarized) is along the X-axis and is parallel to the orientation direction of the long axis of the liquid crystal molecules on the first substrate S21 side of the second liquid crystal layer LC2. On the first substrate S21 side, the second liquid crystal layer LC2 has an arc-shaped refractive index distribution. The second polarization component PL2 (s-polarized) incident from the first substrate S21 to the second liquid crystal layer LC2 is affected by the arc-shaped refractive index distribution of the second liquid crystal layer LC2 and diffuses in the X-axis direction. As the second polarization component PL2 (s-polarized) moves from the first substrate S21 side to the second substrate S22 side in the second liquid crystal layer LC2, it rotates by 90 degrees due to the twisting orientation of the liquid crystal molecules. Thus, the second polarization component PL2 changes from s-polarized to p-polarized. The second electrode E22 is a planar electrode (also called a flat or full-surface electrode) and its entire surface is at a constant potential. Therefore, the liquid crystal molecules on the second substrate S22 side of the second liquid crystal layer LC2 do not form an arc-shaped refractive index distribution. Consequently, the second polarization component PL2 (p-polarized) does not diffuse and remains as is, exiting from the second substrate S22. Thus, the second polarization component PL2 is incident on the second liquid crystal cell 20 in an s-polarized state, diffuses in the X-axis direction, and exits from the second liquid crystal cell 20 in a p-polarized state with a 90-degree optical rotation.

[0114] The second polarization component PL2, passing through the second liquid crystal cell 20, is incident into the third liquid crystal cell 30 in a p-polarized state. The polarization direction of the second polarization component PL2 (p-polarized) is along the Y-axis and is parallel to the orientation direction of the long axis of the liquid crystal molecules on the first substrate S31 side of the third liquid crystal layer LC3. On the first substrate S31 side, the third liquid crystal layer LC3 has an arc-shaped refractive index distribution. The second polarization component PL2 (p-polarized) incident from the first substrate S31 into the third liquid crystal layer LC3 is affected by the arc-shaped refractive index distribution of the third liquid crystal layer LC3 and diffuses in the Y-axis direction. As the second polarization component PL2 (p-polarized) moves from the first substrate S31 side to the second substrate S32 side in the third liquid crystal layer LC3, it rotates by 90 degrees due to the torsional orientation of the liquid crystal molecules. Thus, the second polarization component PL2 changes from p-polarized to s-polarized. The second electrode E32 is a planar electrode (also called a flat or full-surface electrode) and its entire surface is at a constant potential. Therefore, the liquid crystal molecules on the second substrate S32 side of the third liquid crystal layer LC3 do not form an arc-shaped refractive index distribution. Consequently, the second polarization component PL2 (s-polarization) does not diffuse and remains as is, exiting from the second substrate S32. Thus, the second polarization component PL2 is incident into the third liquid crystal cell 30 in a p-polarized state, diffuses in the Y-axis direction, and exits from the third liquid crystal cell 30 in a s-polarized state with a 90-degree optical rotation.

[0115] The second polarization component PL2, passing through the third liquid crystal cell 30, is incident on the fourth liquid crystal cell 40 in an s-polarized state. The polarization direction of the second polarization component PL2 (s-polarization) is along the X-axis and intersects the orientation direction of the long axis of the liquid crystal molecules on the first substrate S31 side of the third liquid crystal layer LC3. On the first substrate S41 side, an arc-shaped refractive index distribution is formed in the fourth liquid crystal layer LC4, but the second polarization component PL2 (s-polarization) does not diffuse and remains oriented towards the second substrate S42. As the second polarization component PL2 (s-polarization) moves from the first substrate S41 side to the second substrate S42 side in the fourth liquid crystal layer LC4, it rotates by 90 degrees due to the torsional orientation of the liquid crystal molecules. Thus, the second polarization component PL2 changes from s-polarization to p-polarization. The second electrode E42 is a planar electrode (also called a flat or full-surface electrode) and its entire surface is at a constant potential. Therefore, the liquid crystal molecules on the second substrate S42 side of the fourth liquid crystal layer LC4 do not form an arc-shaped refractive index distribution. Consequently, the second polarization component PL2 (p-polarized) does not diffuse and is emitted from the second substrate S42 as is. Thus, the second polarization component PL2 is incident into the fourth liquid crystal cell 40 in an s-polarized state, does not diffuse, and is emitted from the fourth liquid crystal cell 40 in a p-polarized state with a 90-degree optical rotation.

[0116] The second polarization component PL2 incident on the liquid crystal light control element 102 undergoes one diffusion in the X-axis direction and one diffusion in the Y-axis direction during the period from incident on the first liquid crystal cell 10 to being emitted from the fourth liquid crystal cell 40. It is incident in a p-polarized state and rotated four times at an angle of 90 degrees, thereby being emitted in a p-polarized state.

[0117] In the first structure, the first polarization component PL1 diffuses in the X-axis direction before optical rotation in the first liquid crystal cell 10, and diffuses in the Y-axis direction before optical rotation in the fourth liquid crystal cell 40. The second polarization component PL2 diffuses in the X-axis direction before optical rotation in the second liquid crystal cell 20, and diffuses in the Y-axis direction before optical rotation in the third liquid crystal cell 30. Here, if we refer to the diffusion of polarization components in each liquid crystal cell before optical rotation as pre-diffusion and diffusion after optical rotation as post-diffusion, then in this first structure, the pre-diffusion of the first polarization component PL1 in the X-axis direction is 1 time, the pre-diffusion in the Y-axis direction is 1 time, and the pre-diffusion of the second polarization component PL2 in the X-axis direction is 1 time, and the pre-diffusion in the Y-axis direction is 1 time. Furthermore, no post-diffusion occurs for any polarization component.

[0118] 1-1-1. Variation of the first structure (1)

[0119] Figure 6 The diagram shows a structure in which a second electrode (E12, E22, E32, E42) is provided in a planar (also called a flat or full-surface) shape in each liquid crystal cell; however, the liquid crystal light control element 102 involved in the first structure is not limited to such a structure. For example, as... Figure 8 As shown, the structure can also be as follows: The second electrode is omitted from the second substrate (S12, S22, S32, S42) of the first to fourth liquid crystal cells, and only an alignment film (not shown) is provided. The alignment direction of the alignment film on the second substrate side is set to be orthogonal (90 degrees ± 10 degrees) to the alignment direction of the alignment film on the first substrate side in each liquid crystal cell. By omitting the second electrode of each liquid crystal cell, it is also possible to make the first polarization component PL1 and the second polarization component PL2... Figure 6 The liquid crystal light control element 102 shown diffuses in the same way.

[0120] 1-1-2. Variation of the first structure (2)

[0121] Figure 9The structure is shown as follows: The second electrodes (E12, E22, E32, E42) of the first to fourth liquid crystal cells are replaced by strip electrodes (third strip electrodes E12A, E22A, E32A, E42A and fourth strip electrodes E12B, E22B, E32B, E42B) instead of planar (also called flat or full-surface) electrodes. In this case, by applying, for example... Figure 7 A constant voltage, like the control signal E shown, can avoid generating a transverse electric field and achieve the same result as... Figure 6 The liquid crystal light control element 102 shown has the same light distribution characteristics.

[0122] 1-2. Second Structure

[0123] In the second structure, the liquid crystal light control element prevents the polarization component from diffusing on the first electrode E11 and E41 side (light incident side) of the first liquid crystal cell 10 and the fourth liquid crystal cell 40, but diffusing on the second electrode E12 and E42 side (light emitting side), diffusing on the first electrode E21 and E31 side (light incident side) of the second liquid crystal cell 20 and the third liquid crystal cell 30, and preventing it from diffusing on the second electrode E22 and E32 side (light emitting side).

[0124] Figure 10 The liquid crystal light control element 102 according to the second structure is shown. The liquid crystal light control element 102 according to the second structure has a first to a fourth liquid crystal cell. In the first liquid crystal cell 10, a first electrode E11 (a first strip electrode E11A and a second strip electrode E11B) is provided on a first substrate S11, and a second electrode E12 (a third strip electrode E12A and a fourth strip electrode E12B) is provided on a second substrate S12. In the second liquid crystal cell 20, a first electrode E21 (a first strip electrode E21A and a second strip electrode E21B) is provided on a first substrate S21, and a second electrode E22 (a third strip electrode E22A and a fourth strip electrode E22B) is provided on a second substrate S22. In the third liquid crystal unit 30, a first electrode E31 (first strip electrode E31A, second strip electrode E31B) is provided on the first substrate S31, and a second electrode E32 (third strip electrode E32A, fourth strip electrode E32B) is provided on the second substrate S32. In the fourth liquid crystal unit 40, a first electrode E41 (first strip electrode E41A, second strip electrode E41B) is provided on the first substrate S41, and a second electrode E42 (third strip electrode E42A, fourth strip electrode E42B) is provided on the second substrate S42.

[0125] Table 2 shows the... Figure 10The control signals applied to each liquid crystal cell of the liquid crystal light control element 102 shown. Figure 10 In the diagram, the strip electrode that has been given a control signal and generates a transverse electric field is represented by a cross-section, while the blank area represents a strip electrode that has not been given a control signal and does not generate a transverse electric field. Furthermore, the control signals A and B shown in Table 3 are... Figure 7 The control signals shown correspond to those shown.

[0126] [Table 2]

[0127]

[0128] As shown in Table 2, control signals E are input to the first strip electrode E11A and the second strip electrode E11B of the first liquid crystal cell 10, control signal A is input to the third strip electrode E12A, and control signal B is input to the fourth strip electrode E12B. The same applies to the fourth liquid crystal cell 40. In the second liquid crystal cell 20, control signal A is applied to the first strip electrode E21A, control signal B is input to the second strip electrode E21B, and control signal E is input to the third strip electrode E22A and the fourth strip electrode E22B. The same applies to the third liquid crystal cell 30. That is, Figure 10 The liquid crystal light control element 102 shown is input with a control signal so that no lateral electric field is generated on the first substrate side in the first liquid crystal cell 10 and the fourth liquid crystal cell 40, and a lateral electric field is generated on the second substrate side; and a lateral electric field is generated on the first substrate side in the second liquid crystal cell 20 and the third liquid crystal cell 30, and no lateral electric field is generated on the second substrate side.

[0129] Next, the operation of the liquid crystal light control element 102 involved in the second structure will be explained by the effect of incident light given by each liquid crystal cell.

[0130] exist Figure 10In this context, we focus on the first polarization component PL1. The first polarization component PL1 is incident on the first liquid crystal cell 10 in an s-polarized state. The first electrode E11 of the first liquid crystal cell 10 does not generate a lateral electric field. Therefore, the first polarization component PL1 does not diffuse through the first electrode E11 and, in the first liquid crystal layer LC1, changes to p-polarization by 90 degrees due to the torsional orientation of the liquid crystal molecules as it moves from the first substrate S11 side towards the second substrate S12 side. At the second electrode E12, a control signal A is applied to the third strip electrode E12A and a control signal B is applied to the fourth strip electrode E12B, thus generating a lateral electric field. Therefore, an arc-shaped refractive index distribution is formed on the second substrate S12 side of the first liquid crystal layer LC1. Since the polarization direction of the first polarization component PL1 (p-polarized) is parallel to the long axis of the liquid crystal molecules, it diffuses in the Y-axis direction due to the influence of the arc-shaped refractive index distribution and is emitted from the second substrate S12. In this way, the first polarization component PL1 is incident on the first liquid crystal cell 10 in an s-polarized state, rotates by 90 degrees to become p-polarized, diffuses in the Y-axis direction and is emitted from the first liquid crystal cell 10.

[0131] The first polarization component PL1, which passes through the first liquid crystal cell 10, is incident on the second liquid crystal cell 20 in a p-polarized state. Similar to the first embodiment, the first polarization component (p-polarized) incident on the second liquid crystal cell 20 does not diffuse and is emitted from the second liquid crystal cell 20 in an s-polarized state with a 90-degree optical rotation.

[0132] The first polarization component PL1, which passes through the second liquid crystal cell 20, is incident on the third liquid crystal cell 30 in an s-polarized state. Similar to the first embodiment, the first polarization component (s-polarized) incident on the third liquid crystal cell 30 does not diffuse and is emitted from the third liquid crystal cell 30 in a p-polarized state with a 90-degree optical rotation.

[0133] The first polarization component PL1, passing through the third liquid crystal cell 30, is incident into the fourth liquid crystal cell 40 in a p-polarized state. The first electrode E41 of the fourth liquid crystal cell 40 does not generate a lateral electric field. Therefore, the first polarization component PL1 does not diffuse through the first electrode E41 and, in the fourth liquid crystal layer LC4, rotates 90 degrees to s-polarization as it moves from the first substrate S41 side towards the second substrate S42 side due to the torsional orientation of the liquid crystal molecules. At the second electrode E42, a control signal A is applied to the third strip electrode E42A and a control signal B is applied to the fourth strip electrode E42B, thus generating a lateral electric field. Therefore, an arc-shaped refractive index distribution is formed on the second substrate S42 side of the fourth liquid crystal layer LC4. Since the polarization direction of the first polarization component PL1 (s-polarized) is parallel to the long axis of the liquid crystal molecules, it diffuses in the X-axis direction due to the influence of the arc-shaped refractive index distribution and is emitted from the second substrate S42. In this way, the first polarization component PL1 is incident on the fourth liquid crystal cell 40 in a p-polarized state, rotates by 90 degrees to become s-polarized, diffuses in the X-axis direction and is emitted from the fourth liquid crystal cell 40.

[0134] The first polarization component PL1 incident on the liquid crystal light control element 102 involved in the second structure diffuses once in the X-axis direction and once in the Y-axis direction during the period from incident on the first liquid crystal cell 10 to being emitted from the fourth liquid crystal cell 40. It is incident in an s-polarized state and rotates light four times at an angle of 90 degrees, thereby being emitted in an s-polarized state.

[0135] Next, we focus on the second polarization component PL2. The second polarization component PL2 is incident on the first liquid crystal cell 10 in a p-polarized state. The first electrode E11 of the first liquid crystal cell 10 does not generate a lateral electric field. Therefore, the second polarization component PL2 (p-polarized) does not diffuse through the first electrode E11, and during its movement from the first substrate S11 side to the second substrate S12 side in the first liquid crystal layer LC1, it undergoes a 90-degree optical rotation due to the torsional orientation of the liquid crystal molecules, thus becoming s-polarized. The second polarization component PL2 (s-polarized) does not diffuse through the second electrode E12 and is emitted from the first liquid crystal cell 10 in an s-polarized state.

[0136] The second polarization component PL2, passing through the first liquid crystal cell 10, is incident into the second liquid crystal cell 20 in an s-polarized state. In the second liquid crystal cell 20, similar to the first structure, the second polarization component PL2 (s-polarized) diffuses along the X-axis on the first substrate S21 side. As the second polarization component PL2 (s-polarized) moves from the first substrate S21 side towards the second substrate S22 side in the second liquid crystal layer LC2, it rotates 90 degrees due to the torsional orientation of the liquid crystal molecules. Thus, the second polarization component PL2 transitions from s-polarization to p-polarization. The second electrode E22 of the second liquid crystal cell 20 does not generate a lateral electric field. Therefore, the second polarization component PL2 does not diffuse through the second electrode E22 and is emitted from the second liquid crystal cell 20 in a p-polarized state.

[0137] The second polarization component PL2, passing through the second liquid crystal cell 20, is incident into the third liquid crystal cell 30 in a p-polarized state. In the third liquid crystal cell 30, similar to the first structure, the second polarization component PL2 (p-polarized) diffuses along the Y-axis on the first substrate S31 side. As the second polarization component PL2 (p-polarized) moves from the first substrate S31 side towards the second substrate S32 side in the third liquid crystal layer LC3, it rotates 90 degrees due to the torsional orientation of the liquid crystal molecules. Thus, the second polarization component PL2 transitions from p-polarized to s-polarized. The second electrode E32 of the third liquid crystal cell 30 does not generate a transverse electric field. Therefore, the second polarization component PL2 does not diffuse through the second electrode E32 and is emitted from the third liquid crystal cell 30 in an s-polarized state.

[0138] The second polarization component PL2, passing through the third liquid crystal cell 30, is incident into the fourth liquid crystal cell 40 in an s-polarized state. The first electrode E41 of the fourth liquid crystal cell 40 does not generate a lateral electric field. Therefore, the second polarization component PL2 (s-polarized) does not diffuse through the first electrode E11 and, during its movement from the first substrate S11 side to the second substrate S12 side in the first liquid crystal layer LC1, it undergoes a 90-degree optical rotation and becomes p-polarized due to the torsional orientation of the liquid crystal molecules. Furthermore, the second polarization component PL2 (p-polarized) does not diffuse through the second substrate S42 and is emitted from the fourth liquid crystal cell 40.

[0139] The second polarization component PL2 incident on the liquid crystal light control element 102 involved in the second structure undergoes one diffusion in the X-axis direction and one diffusion in the Y-axis direction during the period from incident on the first liquid crystal cell 10 to being emitted from the fourth liquid crystal cell 40. It is incident in a p-polarized state and rotated four times at an angle of 90 degrees, thereby being emitted in a p-polarized state.

[0140] In the second structure, the first polarization component PL1 diffuses in the Y-axis direction after optical rotation in the first liquid crystal cell 10, and diffuses in the X-axis direction after optical rotation in the fourth liquid crystal cell 40. The second polarization component PL2 diffuses in the X-axis direction before optical rotation in the second liquid crystal cell 20, and diffuses in the Y-axis direction before optical rotation in the third liquid crystal cell 30. That is, in this second structure, the first polarization component PL1 diffuses 0 times and then 1 time in the X-axis direction, and diffuses 0 times and then 1 time in the Y-axis direction. Similarly, the second polarization component PL2 diffuses 1 time and then 0 times in the X-axis direction, and diffuses 1 time and then 0 times in the Y-axis direction.

[0141] 1-3. Refer to Example 1

[0142] Figure 11 The liquid crystal light control element according to Reference Example 1 is shown. In Reference Example 1, a control signal A is applied to the first strip electrode E11A on the first substrate S11 side of the first liquid crystal cell 10, a control signal B is applied to the second strip electrode E11B, a control signal A is applied to the third strip electrode E12A on the second substrate S12 side, and a control signal B is applied to the fourth strip electrode E12B. The same applies to the second liquid crystal cell 20, the third liquid crystal cell 30, and the fourth liquid crystal cell 40. That is, in any liquid crystal cell, a lateral electric field is generated on both the first substrate (S11, S21, S31, S41) side and the second substrate (S12, S22, S32, S42) side.

[0143] exist Figure 11 In the first liquid crystal cell 10, focusing on the first polarization component PL1, the first polarization component PL1 is incident on the first liquid crystal cell 10 in an s-polarized state. The first polarization component PL1 diffuses in the X-axis direction on the first electrode E11 side of the first liquid crystal cell 10, rotates light by 90 degrees in the first liquid crystal layer LC1, and diffuses in the Y-axis direction on the second electrode E12 side. The first polarization component PL1 rotates light by 90 degrees and is transmitted in the second liquid crystal cell 20 and the third liquid crystal cell 30, diffuses in the Y-axis direction on the first electrode E41 side of the fourth liquid crystal cell 40, rotates light by 90 degrees in the fourth liquid crystal layer LC4, diffuses in the X-axis direction on the second electrode E42 side, and is emitted in an s-polarized state.

[0144] exist Figure 11In the process, focusing on the second polarization component PL2, the second polarization component PL2 is incident on the first liquid crystal cell 10 in a p-polarized state. The second polarization component PL2 rotates 90 degrees in the first liquid crystal cell 10 and is incident on the second liquid crystal cell 20 in an s-polarized state without diffusion in the first liquid crystal cell 10. The second polarization component PL2 diffuses in the X-axis direction on the first electrode E21 side of the second liquid crystal cell 20, becomes p-polarized with 90 degrees in the second liquid crystal layer LC2, and diffuses in the Y-axis direction on the second electrode E22 side. Furthermore, the second polarization component PL2 diffuses in the Y-axis direction on the first electrode E31 side of the third liquid crystal cell 30, becomes s-polarized with 90 degrees in the third liquid crystal layer LC3, and diffuses in the X-axis direction on the second electrode E22 side. Subsequently, the second polarization component PL2 rotates 90 degrees in the fourth liquid crystal cell 40 and is emitted in a p-polarized state without diffusion in the fourth liquid crystal cell 40.

[0145] Thus, for the liquid crystal light control element involved in Reference Example 1, the first polarization component PL1 diffuses in the X-axis direction and the Y-axis direction in the first liquid crystal cell 10 and the fourth liquid crystal cell 40, and the second polarization component PL2 diffuses in the X-axis direction and the Y-axis direction in the second liquid crystal cell 20 and the third liquid crystal cell 30.

[0146] 1-4.Angle characteristics

[0147] Figure 12A A graph showing the brightness-angle characteristics of the liquid crystal light control element 102 involved in the first and second structures is provided. Furthermore, Figure 12A The characteristics of Reference Example 1 are shown in this diagram. Additionally, Figure 12A The horizontal axis of the chart shown represents the polar angle. For example... Figure 12E As shown, 0 degrees represents the light-emitting surface of the liquid crystal light control element 102 when viewed from directly opposite. The polar angles shown in the graph represent the angles when tilted in the positive and negative directions along the X-axis. The vertical axis of the graph represents the brightness when the brightness at the center (polar angle 0 degrees) is normalized to 100%.

[0148] exist Figure 12AAs shown in the diagram, for the characteristics related to the first structure of the liquid crystal light control element 102, although the brightness decreases by about 20% from the center brightness in the range of polar angles of +20° to +40° and -20° to -40°, a constant brightness distribution is obtained within this range. In the first structure, a structure is adopted such that each polarization component diffuses in the liquid crystal layer before optical rotation and does not diffuse after optical rotation, as described above, thereby showing a substantially flat intensity distribution within a constant range of polar angles. That is, the polarization components that are not completely optically rotated in the liquid crystal layer and diffuse in the predetermined direction (X-axis direction or Y-axis direction) in the liquid crystal cell do not diffuse again through the electrode on the light emission side, thereby achieving a flat characteristic in the angular characteristics of brightness.

[0149] Furthermore, the aforementioned phrase "causing each polarization component to diffuse before optical rotation and not diffuse after optical rotation" refers to a polarization component diffusing before optical rotation within a certain liquid crystal panel, and then not diffusing further after optical rotation within the same liquid crystal panel. It does not include the case where a polarization component diffuses in different liquid crystal panels during the passage of a liquid crystal light control element. For example, in the first structure described above, the first polarization component diffuses in both the first and fourth liquid crystal cells. However, in the first liquid crystal cell, it diffuses before optical rotation (diffuses first) and does not diffuse after optical rotation. Similarly, in the fourth liquid crystal cell, it diffuses before optical rotation but does not diffuse after optical rotation.

[0150] Regarding the characteristics of the second structure of the liquid crystal light control element 102, it is known that although the brightness decreases by about 40% from the center brightness in the range of polar angles of +20° to +40° and -20° to -40°, a constant brightness distribution is obtained within this range. In the second structure, the diffusion of the first polarization component PL1 occurs after optical rotation in the liquid crystal layer, while the diffusion of the second polarization component PL2 occurs before optical rotation. The characteristics of the second structure are that although the brightness decreases in the range of polar angles of +20° to +40° and -20° to -40°, the distribution is close to the characteristics of the first structure. Thus, it is known that by allowing each polarization component to diffuse once in the X-axis direction and once in the Y-axis direction, a relatively flat brightness characteristic is obtained in the range of polar angles of +20° to +40° and -20° to -40°.

[0151] Thus, if the first structure is compared with the second structure, it is shown that: in the first structure, both the first polarization component and the second polarization component undergo one pre-diffusion in the X-axis direction during the process of passing through the liquid crystal light control element 102; on the other hand, in the second structure, the first polarization component undergoes one post-diffusion in the X-axis direction, and the second polarization component undergoes one pre-diffusion in the X-axis direction. Pre-diffusion suppresses brightness reduction more effectively than post-diffusion, and maintains a larger polar angle range for constant brightness.

[0152] In contrast, the liquid crystal light control element shown in Reference Example 1 exhibits the following trend: the intensity of the brightness distribution is greatest at the polar angle of 0 degrees, and decreases linearly as the polar angle increases in both the positive and negative directions (i.e., the left-right direction). It can be seen that the liquid crystal light control element in Reference Example 1, due to the diffusion of polarization components in the liquid crystal layer, results in a brightness distribution that decreases linearly in the polar angle direction, unlike the characteristics in the first and second structures. That is, it can be seen that by diffusing polarization components in the liquid crystal cell in the optical rotation direction, a brightness distribution that decreases linearly in the polar angle direction is obtained.

[0153] More specifically, in Reference Example 1, the first polarization component undergoes one pre-diffusion in the X-axis direction, but subsequent diffusion occurs in the Y-axis direction within the immediately following identical liquid crystal cell (the first liquid crystal cell). Furthermore, the second polarization component undergoes one pre-diffusion in the X-axis direction, but subsequent diffusion occurs in the Y-axis direction within the immediately preceding identical liquid crystal cell (the second liquid crystal cell). Further, in Reference Example 1, the first polarization component undergoes one pre-diffusion in the Y-axis direction, but subsequent diffusion occurs in the X-axis direction within the immediately following identical liquid crystal cell (the fourth liquid crystal cell). Furthermore, the second polarization component undergoes one pre-diffusion in the Y-axis direction, but subsequent diffusion occurs in the X-axis direction within the immediately following identical liquid crystal cell (the third liquid crystal cell). That is, in Reference Example 1, each polarization component undergoes one pre-diffusion and one subsequent diffusion in the X-axis direction, but all are accompanied by diffusion in the Y-axis direction within the same liquid crystal cell. Figure 12A It is shown that if diffusion occurs before and after optical rotation within the same liquid crystal cell, even if the number of diffusions is the same, the brightness decreases monotonically as the polar angle increases compared to the case where diffusion occurs only through diffusion (structure 1).

[0154] In addition, according to Figure 12A For any of the first structure, the second structure, and Reference Example 1, at a polar angle of approximately 50 degrees, the brightness becomes half that at a polar angle of 0 degrees, and the brightness decreases in the same manner below this point. If the region up to which the brightness becomes half is called the half-value width, then in the first structure, the half-value width is the same as in Reference Example 1, and compared to Reference Example 1, the brightness within the half-value width is increased and maintained constant. In the second structure, the half-value width is the same as in Reference Example 1, and compared to Reference Example 1, the brightness within the half-value width is decreased and maintained constant.

[0155] Next, the distribution of emitted light from each structure is shown. Figure 12BThe distribution of emitted light in the first structure is shown. In the first structure, the first polarization component PL1 and the second polarization component PL2 are diffused once in the X-axis direction and once in the Y-axis direction through the electrodes on the light incident side of each liquid crystal cell, thereby obtaining a good distribution with a near-square shape. Figure 12C The distribution of emitted light in the second structure is shown. In the second structure, the first polarization component PL1 diffuses in the second substrate (the substrate on the light emission side) of the first liquid crystal cell 10 and the fourth liquid crystal cell 40, and the second polarization component PL2 diffuses in the first substrate (the substrate on the light incident side) of the second liquid crystal cell 20 and the third liquid crystal cell 30, thereby obtaining a distribution that is nearly square, similar to that in the first structure.

[0156] on the other hand, Figure 12D The distribution of emitted light in Reference Example 1 is shown. In Reference Example 1, the first polarization component PL1 diffuses twice in the X-axis direction and the Y-axis direction in the first liquid crystal cell 10 and the fourth liquid crystal cell 40, and the second polarization component PL2 diffuses twice in the X-axis direction and the Y-axis direction in the second liquid crystal cell 20 and the third liquid crystal cell 30, thereby obtaining a distribution that is closer to a circle than the distribution obtained in the first structure and the second structure.

[0157] exist Figure 12A In the diagram, if the characteristics of the first structure and the second structure are compared with those of Reference Example 1, it can be seen that the light intensity is higher when diffusion occurs on the first substrate (the substrate on the light incident side) side in each liquid crystal cell. On the other hand, as in Reference Example 1, by increasing the number of diffusions, the decrease in brightness near the polar angle of 0 degrees can be reduced.

[0158] like Figures 12B to 12D As shown, it can be seen that, in a liquid crystal cell, diffusing the polarization component before and after optical rotation based on the liquid crystal layer results in a well-shaped (square) distribution when diffusing before optical rotation and not diffusing after optical rotation. Furthermore, it can be seen that, by diffusing the polarization component in the liquid crystal layer only before and after optical rotation in a liquid crystal cell, a well-shaped (square) distribution is also obtained.

[0159] If reference Figure 5A as well as Figure 5B As explained, some polarization components remain after passing through each liquid crystal cell without being fully rotated. Therefore, compared to diffusion in different directions before and after rotation in one liquid crystal cell, the corresponding polarization components diffuse in other liquid crystal cells, thereby improving the light distribution characteristics and obtaining a well-shaped illumination distribution.

[0160] According to this embodiment, in a liquid crystal cell with a four-level configuration, a structure is adopted in which each polarization component diffuses before optical rotation in the liquid crystal layer and does not diffuse after optical rotation, thereby achieving a substantially flat intensity distribution within a constant polar angle range and obtaining an illumination distribution with good shape. Furthermore, in a liquid crystal cell with a four-level configuration, by adopting a structure in which each polarization component diffuses before or after optical rotation in the liquid crystal layer and does not diffuse before or after optical rotation within a single liquid crystal cell, a substantially flat intensity distribution within a constant polar angle range can also be achieved, resulting in an illumination distribution with good shape.

[0161] [Second Implementation]

[0162] This embodiment illustrates an example where the liquid crystal light control element is composed of five liquid crystal cells. Each liquid crystal cell has a liquid crystal layer between a pair of substrates, and at least one substrate has a liquid crystal layer. Figure 1 The strip electrode shown.

[0163] 2-1. The third structure

[0164] Figure 13 The diagram shows the electrode arrangement in each liquid crystal cell of the liquid crystal light control element 102 according to the third structure, and the state when light incident on the liquid crystal light control element 102 passes through each liquid crystal cell. The liquid crystal light control element 102 according to the third structure has 1 to 5 liquid crystal cells. The structure of each liquid crystal cell is as described in the first embodiment, with the first electrode on the first substrate side being composed of a strip electrode, and the second electrode on the second substrate side being composed of a strip electrode.

[0165] like Figure 13 As shown, the liquid crystal light control element 102 involved in the third structure is configured such that a first liquid crystal unit 10, a second liquid crystal unit 20, a third liquid crystal unit 30, a fourth liquid crystal unit 40 and a fifth liquid crystal unit 50 are superimposed from the light incident side toward the emission side.

[0166] The first liquid crystal unit 10 is configured such that the first strip electrode E11A and the second strip electrode E11B on the first substrate S11 side extend in the X-axis direction, and the third strip electrode E12A and the fourth strip electrode E12B on the second substrate S12 side extend in the Y-axis direction. The second liquid crystal unit 20 and the third liquid crystal unit 30 are configured such that the first strip electrode E21A, E31A and the second strip electrode E21B, E31B on the first substrates S21 and S31 side extend in the Y-axis direction, and the third strip electrode E22A, E32A and the fourth strip electrode E22B, E32B on the second substrates S22 and S32 side extend in the X-axis direction. The fourth liquid crystal cell 40 and the fifth liquid crystal cell 50 are configured such that the first strip electrodes E41A, E51A and the second strip electrodes E41B, E51B on the first substrates S41 and S51 extend in the X-axis direction, and the third strip electrodes E42A, E52A and the fourth strip electrodes E42B, E52B on the second substrates S42 and S52 extend in the Y-axis direction. Furthermore, the alignment direction of the alignment film of each liquid crystal cell is arranged in a direction intersecting the extension direction of the strip electrodes, which is the same as in the first embodiment. This embodiment can also be described as... Figure 9 , Figure 10 The modified example of the first embodiment shown further includes a structure in which a liquid crystal cell is added and stacked on the incident side. Furthermore, this added liquid crystal cell can be described as the same liquid crystal cell as the third to fourth liquid crystal cells mentioned in the modified example of the first embodiment, and is arranged in the same orientation as these liquid crystal cells.

[0167] Figure 13 Similar to the first embodiment, the electrodes to which a control signal is applied and which form a transverse electric field are shown by cross-sectional lines. Furthermore, Figure 13 The table is inserted to indicate the state of the polarization components of light containing the first polarization component PL1 and the second polarization component PL2 as they pass through the first electrode, the liquid crystal layer, and the second electrode of each liquid crystal cell, using terms such as transmission, optical rotation, and diffusion.

[0168] Table 3 shows the... Figure 13 The control signals applied to each liquid crystal cell of the liquid crystal light control element 102 involved in the third structure shown.

[0169] [Table 3]

[0170]

[0171] As shown in Table 3, in each liquid crystal cell of the liquid crystal light control element 102 involved in the third structure, rectangular wave control signals A and B are applied to the first electrode (first strip electrode, second strip electrode) on the first substrate side (light incident side), and a constant voltage control signal E is applied to the second electrode (third strip electrode, fourth strip electrode) on the second substrate side (light emitting side). That is, for Figure 13 In the case of the liquid crystal light control element 102 involved in the third structure shown, control signals A and B are applied to the first electrode of each liquid crystal cell, and control signal E is applied to the second electrode, thereby generating a lateral electric field only on the first substrate side.

[0172] Next, the states of light diffusion, rotation, and transmission incident on the liquid crystal light control element 102 involved in the third structure will be described. In the third structure, the initial state of the first polarization component PL1 (the state immediately preceding the incident on the liquid crystal light control element 102) is also set to s-polarization, and the initial state of the second polarization component PL2 is set to p-polarization.

[0173] exist Figure 13 Focusing on the first polarization component PL1, the first polarization component PL1 is incident on the first liquid crystal cell 10 in an s-polarized state. The s-polarized PL1 incident on the first liquid crystal cell 10 does not diffuse through the first electrode E11, but becomes p-polarized with a 90-degree optical rotation in the first liquid crystal layer LC1, and does not diffuse through the second electrode E12, but exits from the first liquid crystal cell 10. The p-polarized PL1 incident on the second liquid crystal cell 20 does not diffuse through the first electrode E21, but becomes s-polarized with a 90-degree optical rotation in the second liquid crystal layer LC2, and does not diffuse through the second electrode E22, but exits from the second liquid crystal cell 20. The s-polarized PL1 incident on the third liquid crystal cell 30 diffuses in the X-axis direction through the first electrode E31, becomes p-polarized with a 90-degree optical rotation in the third liquid crystal layer LC3, and does not diffuse through the second electrode E32, but exits from the third liquid crystal cell 30. The first polarization component PL1 (p-polarized) incident on the fourth liquid crystal cell 40 diffuses along the Y-axis through the first electrode E41, undergoes 90-degree optical rotation in the fourth liquid crystal layer LC4 to become s-polarized, does not diffuse through the second electrode E42, and is emitted from the fourth liquid crystal cell 40. The first polarization component PL1 (s-polarized) incident on the fifth liquid crystal cell 50 does not diffuse through the first electrode E51, undergoes 90-degree optical rotation in the fifth liquid crystal layer LC5 to become p-polarized, does not diffuse through the second electrode E52, and is emitted from the fifth liquid crystal cell 50. Thus, the first polarization component PL1 (s-polarized) incident on the liquid crystal light control element 102 involved in the third structure undergoes one diffusion along the X-axis and one diffusion along the Y-axis, undergoes five optical rotations in the liquid crystal layer, and is emitted in a p-polarized state.

[0174] Figure 13 Focusing on the second polarization component PL2, the second polarization component PL2 is incident on the first liquid crystal cell 10 in a p-polarized state. The p-polarized PL2 incident on the first liquid crystal cell 10 diffuses along the Y-axis through the first electrode E11, becomes s-polarized with a 90-degree optical rotation in the first liquid crystal layer LC1, does not diffuse through the second electrode E12, and exits from the first liquid crystal cell 10. The s-polarized PL2 incident on the second liquid crystal cell 20 diffuses along the X-axis through the first electrode E21, becomes p-polarized with a 90-degree optical rotation in the second liquid crystal layer LC2, does not diffuse through the second electrode E22, and exits from the second liquid crystal cell 20. The p-polarized PL2 incident on the third liquid crystal cell 30 does not diffuse through the first electrode E31, becomes s-polarized with a 90-degree optical rotation in the third liquid crystal layer LC3, does not diffuse through the second electrode E32, and exits from the third liquid crystal cell 30. The second polarization component PL2 (s-polarized) incident on the fourth liquid crystal cell 40 does not diffuse through the first electrode E41, but becomes p-polarized by 90-degree optical rotation in the fourth liquid crystal layer LC4, and is emitted from the fourth liquid crystal cell 40 without diffusing through the second electrode E42. The second polarization component PL2 (p-polarized) incident on the fifth liquid crystal cell 50 diffuses in the Y-axis direction through the first electrode E51, becomes s-polarized by 90-degree optical rotation in the fifth liquid crystal layer LC5, and is emitted from the fifth liquid crystal cell 50 without diffusing through the second electrode E52. Thus, the second polarization component PL2 (p-polarized) incident on the liquid crystal light control element 102 involved in the third structure undergoes one diffusion in the X-axis direction and two diffusions in the Y-axis direction, and is emitted in an s-polarized state after five optical rotations in the liquid crystal layer.

[0175] In the third structure, the first polarization component PL1 diffuses in the X-axis direction before optical rotation in the third liquid crystal cell 30, and diffuses in the Y-axis direction before optical rotation in the fourth liquid crystal cell 40. The second polarization component PL2 diffuses in the X-axis direction before optical rotation in the second liquid crystal cell 20, diffuses in the Y-axis direction before optical rotation in the third liquid crystal cell 30, and further diffuses in the Y-axis direction before optical rotation in the fifth liquid crystal cell 50. Additionally, in the third structure, the second electrodes E12, E22, E32, R42, and E52 can also be made... Figure 6 Electrodes in a planar (also called flat or full-surface) shape, as shown, or as... Figure 8 The diagram shows a structure without a second electrode.

[0176] 2-2. Structure 4

[0177] In the fourth structure, the liquid crystal light control element prevents the polarization component from diffusing on the first electrode E11, E41, and E51 sides (light incident side) of the first liquid crystal cell 10, the second liquid crystal cell 20, and the fifth liquid crystal cell 50, but diffusing on the second electrode E12, E42, and E52 sides (light emitting side), diffusing on the first electrode E21 and E31 sides (light incident side) of the third liquid crystal cell 30 and the fourth liquid crystal cell 40, and preventing it from diffusing on the second electrode E22 and E32 sides.

[0178] Figure 14 The diagram shows the electrode configuration in each liquid crystal cell of the liquid crystal light control element 102 involved in the fourth structure, and the state when light incident on the liquid crystal light control element 102 passes through each liquid crystal cell. The configuration of the strip electrodes in each liquid crystal cell is the same as in the third structure.

[0179] Table 4 shows the... Figure 14 The control signals applied to each liquid crystal cell of the liquid crystal light control element 102 involved in the fourth structure shown.

[0180] [Table 4]

[0181]

[0182] As shown in Table 4, for the liquid crystal light control element 102 involved in the fourth structure, in the first liquid crystal cell 10, the second liquid crystal cell 20 and the fifth liquid crystal cell 50, a control signal E with a constant voltage is applied to the first electrode E11, E21, E51 (first strip electrode E11A, E21A, E51A, second strip electrode E11B, E21B, E51B) on the light incident side, and control signals A and B are applied to the second electrode E12, E22, E52 (third strip electrode E12A, E22A, E52A, fourth strip electrode E12B, E22B, E52B) on the light emission side after rotation. Furthermore, in the third liquid crystal cell 30 and the fourth liquid crystal cell 40, control signals A and B are applied to the first electrodes E31 and E41 (first strip electrodes E31A, E41A, second strip electrodes E31B, E41B) on the light incident side, and a control signal E with a constant voltage is applied to the second electrodes E32 and E42 (third strip electrodes E32A, E42A, fourth strip electrodes E32B, E42B). That is, for Figure 14 Regarding the liquid crystal light control element 102 involved in the fourth structure shown, no lateral electric field is generated on the side of the first substrate S11, S21, and S51 of the first liquid crystal cell 10, the second liquid crystal cell 20, and the fifth liquid crystal cell 50, while a lateral electric field is generated on the side of the second substrate S12, S22, and S52. In the third liquid crystal cell 30 and the fourth liquid crystal cell 40, a lateral electric field is generated on the side of the first substrate S31 and S41, while no lateral electric field is generated on the side of the second substrate S32 and S42.

[0183] Next, the states of light diffusion, rotation, and transmission incident on the liquid crystal light control element 102 involved in the fourth structure will be described. In the fourth structure, the initial state of the first polarization component PL1 (the state immediately preceding the incident on the liquid crystal light control element 102) is also set to s-polarization, and the initial state of the second polarization component PL2 is set to p-polarization.

[0184] exist Figure 14 Focusing on the first polarization component PL1, the first polarization component PL1 is incident on the first liquid crystal cell 10 in an s-polarized state. The s-polarized PL1 incident on the first liquid crystal cell 10 does not diffuse through the first electrode E11, but becomes p-polarized with a 90-degree optical rotation in the first liquid crystal layer LC1, and does not diffuse through the second electrode E12, but exits from the first liquid crystal cell 10. The p-polarized PL1 incident on the second liquid crystal cell 20 does not diffuse through the first electrode E21, but becomes s-polarized with a 90-degree optical rotation in the second liquid crystal layer LC2, and does not diffuse through the second electrode E22, but exits from the second liquid crystal cell 20. The s-polarized PL1 incident on the third liquid crystal cell 30 diffuses in the X-axis direction through the first electrode E31, becomes p-polarized with a 90-degree optical rotation in the third liquid crystal layer LC3, and does not diffuse through the second electrode E32, but exits from the third liquid crystal cell 30. The first polarization component PL1 (p-polarized) incident on the fourth liquid crystal cell 40 diffuses along the Y-axis through the first electrode E41, undergoes 90-degree optical rotation in the fourth liquid crystal layer LC4 to become s-polarized, does not diffuse through the second electrode E42, and is emitted from the fourth liquid crystal cell 40. The first polarization component PL1 (s-polarized) incident on the fifth liquid crystal cell 50 does not diffuse through the first electrode E51, undergoes 90-degree optical rotation in the fifth liquid crystal layer LC5 to become p-polarized, does not diffuse through the second electrode E52, and is emitted from the fifth liquid crystal cell 50. Thus, the first polarization component PL1 (s-polarized) incident on the liquid crystal light control element 102 involved in the fourth structure undergoes one diffusion along the X-axis and one diffusion along the Y-axis, undergoes five optical rotations in the liquid crystal layer, and is emitted in a p-polarized state.

[0185] exist Figure 14Focusing on the second polarization component PL2, the second polarization component PL2 is incident on the first liquid crystal cell 10 in a p-polarized state. The p-polarized PL2 incident on the first liquid crystal cell 10 does not diffuse through the first electrode E11, but becomes s-polarized with a 90-degree optical rotation in the first liquid crystal layer LC1, diffuses along the X-axis through the second electrode E12, and exits from the first liquid crystal cell 10. The s-polarized PL2 incident on the second liquid crystal cell 20 does not diffuse through the first electrode E21, but becomes p-polarized with a 90-degree optical rotation in the second liquid crystal layer LC2, diffuses along the Y-axis through the second electrode E22, and exits from the second liquid crystal cell 20. The p-polarized PL2 incident on the third liquid crystal cell 30 does not diffuse through the first electrode E31, but becomes s-polarized with a 90-degree optical rotation in the third liquid crystal layer LC3, does not diffuse through the second electrode E32, and exits from the third liquid crystal cell 30. The second polarization component PL2 (s-polarized) incident on the fourth liquid crystal cell 40 does not diffuse through the first electrode E41, but becomes p-polarized by 90-degree optical rotation in the fourth liquid crystal layer LC4, and is emitted from the fourth liquid crystal cell 40 without diffusing through the second electrode E42. The second polarization component PL2 (p-polarized) incident on the fifth liquid crystal cell 50 does not diffuse through the first electrode E51, but becomes s-polarized by 90-degree optical rotation in the fifth liquid crystal layer LC5, and diffuses in the X-axis direction through the second electrode E52, and is emitted from the fifth liquid crystal cell 50. Thus, the second polarization component PL2 (p-polarized) incident on the liquid crystal light control element 102 involved in the fourth structure undergoes two diffusions in the X-axis direction and one diffusion in the Y-axis direction, and is emitted in an s-polarized state after undergoing five optical rotations in the liquid crystal layer.

[0186] In the fourth structure, the first polarization component PL1 diffuses in the X-axis direction before optical rotation in the third liquid crystal cell 30 and diffuses in the Y-axis direction before optical rotation in the fourth liquid crystal cell 40. The second polarization component PL2 diffuses in the X-axis direction after optical rotation in the first liquid crystal cell 10, diffuses in the Y-axis direction after optical rotation in the second liquid crystal cell 20, and diffuses in the X-axis direction after optical rotation in the fifth liquid crystal cell 50.

[0187] 2-3. Refer to Example 2

[0188] Figure 15The liquid crystal light control element according to Reference Example 2 is shown. In Reference Example 2, a control signal A is applied to the first strip electrode E11A on the first substrate S11 side of the first liquid crystal cell 10, a control signal B is applied to the second strip electrode E11B, a control signal A is applied to the third strip electrode E12A on the second substrate S12 side, and a control signal B is applied to the fourth strip electrode E12B. The same applies to the second liquid crystal cell 20, the third liquid crystal cell 30, the fourth liquid crystal cell 40, and the fifth liquid crystal cell 50. That is, a lateral electric field is generated on both substrate sides in all of the first to fifth liquid crystal cells.

[0189] exist Figure 15 In the above, focusing on the first polarization component PL1, the first polarization component PL1 is incident on the first liquid crystal cell 10 in an s-polarized state. The first polarization component PL1 does not diffuse in the first liquid crystal cell 10, but becomes p-polarized in the first liquid crystal layer LC1 due to 90-degree optical rotation. The first polarization component PL1 also does not diffuse in the second liquid crystal cell 20, but becomes s-polarized again in the second liquid crystal layer LC2 due to 90-degree optical rotation. The first polarization component PL1, in an s-polarized state, is incident on the third liquid crystal cell 30, diffuses in the X-axis direction through the first electrode E31, becomes p-polarized in the third liquid crystal layer LC3 due to 90-degree optical rotation, and diffuses in the Y-axis direction through the second electrode E32. The first polarization component PL1, in a p-polarized state, is incident on the fourth liquid crystal cell 40, diffuses in the Y-axis direction through the first electrode E41, becomes s-polarized in the fourth liquid crystal layer LC4 due to 90-degree optical rotation, and diffuses in the X-axis direction through the second electrode E42. The first polarization component PL1 does not diffuse in the fifth liquid crystal cell 50, but is emitted in the fifth liquid crystal layer LC5 with a 90-degree rotation and a p-polarized state.

[0190] exist Figure 15In the first liquid crystal cell 10, focusing on the second polarization component PL2, it is incident in a p-polarized state. PL2 diffuses along the Y-axis through the first electrode E11, becomes s-polarized in the first liquid crystal layer LC1 by 90 degrees of optical rotation, and then diffuses along the X-axis through the second electrode E12. PL2, also in a s-polarized state, is incident on the second liquid crystal cell 20, diffuses along the X-axis through the first electrode E21, becomes p-polarized in the second liquid crystal layer LC2 by 90 degrees of optical rotation, and then diffuses along the Y-axis through the second electrode E22. PL2 does not diffuse in the third liquid crystal cell 30, but becomes s-polarized in the third liquid crystal layer LC3 by 90 degrees of optical rotation. PL2 also does not diffuse in the fourth liquid crystal cell, but becomes p-polarized in the fourth liquid crystal layer LC4 by 90 degrees of diffusion. The second polarization component PL2 is incident into the fifth liquid crystal cell 50 in a p-polarized state, diffuses in the Y-axis direction through the first electrode E51, becomes s-polarized in the fifth liquid crystal layer LC5 by 90 degrees of optical rotation, diffuses in the X-axis direction through the second electrode E52, and is emitted in an s-polarized state.

[0191] Thus, for the liquid crystal light control element involved in Reference Example 2, the first polarization component PL1 diffuses in the X-axis direction and the Y-axis direction in the third liquid crystal cell 30 and the fourth liquid crystal cell 40, and the second polarization component PL2 diffuses in the X-axis direction and the Y-axis direction in the first liquid crystal cell 10, the second liquid crystal cell 20 and the fifth liquid crystal cell 50.

[0192] 2-4.Angle characteristics

[0193] Figure 16 A graph showing the brightness-angle characteristics of the liquid crystal light control element 102 involved in the third and fourth structures is provided. Furthermore, Figure 16 The characteristics of Reference Example 2 are shown in this diagram. Additionally, with... Figure 12A same, Figure 16 The horizontal axis of the chart shows the polar angle, and the vertical axis shows the brightness when the brightness at the center (polar angle 0 degrees) is normalized to 100%.

[0194] exist Figure 16 As shown in the diagram, although the brightness of the third structure of the liquid crystal light control element 102 decreases by about 5% from the center brightness in the range of approximately +10° to +45° and approximately -10° to -45° polar angles, a constant brightness distribution is obtained within this range. In the third structure, a substantially flat intensity distribution is obtained within a constant polar angle range by employing a structure that allows each polarization component to diffuse before optical rotation and not diffuse after optical rotation in the liquid crystal layer. Furthermore, it can be seen that the range of polar angles where the brightness distribution is constant is larger compared to the first structure.

[0195] It can be seen that, although the brightness of the fourth structure of the liquid crystal light control element 102 decreases by about 45% from the center brightness in the range of polar angles approximately +20° to +45° and -20° to -45°, a constant brightness distribution is obtained within this range. In the fourth structure, the diffusion of the first polarization component PL1 occurs before the light rotation in the liquid crystal layer, and the diffusion of the second polarization component PL2 occurs after the light rotation. Although the brightness of the fourth structure decreases in the range of polar angles approximately +20° to +45° and -20° to -45°, a distribution close to the characteristics involved in the fourth structure is obtained.

[0196] Thus, if the third structure is compared with the fourth structure, it is shown that: in the third structure, the first polarization component and the second polarization component each undergo one pre-diffusion in the X-axis direction during the process of passing through the liquid crystal light control element 102; on the other hand, in the fourth structure, the first polarization component undergoes one pre-diffusion in the X-axis direction, and the second polarization component undergoes two post-diffusions in the X-axis direction. Compared with one pre-diffusion and two post-diffusions, the two pre-diffusions better suppress the decrease in brightness and maintain a larger polar angle range of constant brightness.

[0197] Comparing the third structure with the first structure, the brightness is relatively higher, and the range of constant polar angles is larger. The same trend is observed when comparing the fourth structure with the second structure. One reason for this change in properties is believed to be that the second polarization component PL2 diffuses one more time than the first structure.

[0198] The liquid crystal light control element shown in Reference Example 2 exhibits the following trend: the intensity of the brightness distribution is greatest at the polar angle of 0 degrees, and decreases linearly as the polar angle increases in both the positive and negative directions (i.e., the left and right directions). It can be seen that the liquid crystal light control element involved in Reference Example 2 is the same as that in Reference Example 1, achieving a brightness distribution that decreases linearly in the polar angle direction by diffusing each polarization component in the liquid crystal layer.

[0199] More specifically, in Reference Example 2, the first polarization component undergoes one pre-diffusion in the X-axis direction, but subsequent diffusion in the Y-axis direction within the immediately following identical liquid crystal cell (the third liquid crystal cell). Furthermore, the second polarization component undergoes one pre-diffusion in the X-axis direction, but subsequent diffusion in the Y-axis direction within the immediately preceding identical liquid crystal cell (the second liquid crystal cell). Further in Reference Example 2, the first polarization component undergoes one pre-diffusion in the Y-axis direction, but subsequent diffusion in the X-axis direction within the immediately following identical liquid crystal cell (the fourth liquid crystal cell). Additionally, the second polarization component undergoes one pre-diffusion in the Y-axis direction within the first and fifth liquid crystal cells, and subsequent diffusion in the X-axis direction within the immediately following identical liquid crystal cell. That is, in Reference Example 2, the first polarization component undergoes one pre-diffusion and one subsequent diffusion in the X-axis direction, but both are accompanied by diffusion in the Y-axis direction within the same liquid crystal cell. Furthermore, in Reference Example 2, the second polarization component undergoes one pre-diffusion and two post-diffusions in the X-axis direction, but both are accompanied by diffusion in the Y-axis direction within the same liquid crystal cell. According to Figure 16 It is shown that if diffusion occurs before and after optical rotation within the same liquid crystal cell, even if the number of diffusions is the same, compared with the case where diffusion occurs only through diffusion (structure 3), the brightness decreases monotonically as the polar angle increases.

[0200] In addition, according to Figure 16 In the third structure, the half-value width is the same as that of Reference Example 2, and compared with Reference Example 2, the brightness within the half-value width is increased and kept constant. In the fourth structure, the half-value width is the same as that of Reference Example 2, and compared with Reference Example 2, the brightness within the half-value width is decreased and kept constant.

[0201] According to this embodiment, in a liquid crystal cell with a 5-level configuration, a structure is adopted in which each polarization component diffuses before optical rotation in the liquid crystal layer and does not diffuse after optical rotation, thereby achieving a substantially flat intensity distribution within a constant polar angle range. Furthermore, in a liquid crystal cell with a 5-level configuration, by adopting a structure in which each polarization component diffuses before or after optical rotation in the liquid crystal layer and does not diffuse before or after optical rotation within a single liquid crystal cell, a substantially flat intensity distribution within a constant polar angle range can also be achieved.

[0202] [Third Implementation]

[0203] 3-1. Structure 5

[0204] Figure 17The diagram shows the electrode arrangement in each liquid crystal cell of the liquid crystal light control element 102 according to the fifth structure, and the state when light incident on the liquid crystal light control element 102 passes through each liquid crystal cell. The liquid crystal light control element 102 according to the fifth structure has 1 to 6 liquid crystal cells. The structure of each liquid crystal cell is as described in the first embodiment, with the first electrode on the first substrate side being composed of a strip electrode, and the second electrode on the second substrate side being composed of a strip electrode.

[0205] like Figure 17 As shown, the liquid crystal light control element 102 involved in the fifth structure is configured such that a first liquid crystal unit 10, a second liquid crystal unit 20, a third liquid crystal unit 30, a fourth liquid crystal unit 40, a fifth liquid crystal unit 50 and a sixth liquid crystal unit 60 are superimposed from the light incident side toward the emission side.

[0206] The first liquid crystal unit 10 and the second liquid crystal unit 20 are configured such that the first strip electrodes E11A, E21A and the second strip electrodes E11B, E21B on the first substrate S11 and S21 extend in the X-axis direction, and the third strip electrodes E12A, E22A and the fourth strip electrodes E12B, E22B on the second substrate S12 and S22 extend in the Y-axis direction. The third liquid crystal unit 30 and the fourth liquid crystal unit 40 are configured such that the first strip electrodes E31A, E41A and the second strip electrodes E31B, E41B on the first substrate S31 and S41 extend in the Y-axis direction, and the third strip electrodes E32A, E42A and the fourth strip electrodes E32B, E42B on the second substrate S32 and S42 extend in the X-axis direction. The fifth liquid crystal cell 50 and the sixth liquid crystal cell 60 are configured such that the first strip electrodes E51A, E61A and the second strip electrodes E51B, E61B on the first substrates S51 and S61 extend in the X-axis direction, and the third strip electrodes E52A, E62A and the fourth strip electrodes E52B, E62B on the second substrates S52 and S62 extend in the Y-axis direction. Furthermore, the alignment direction of the alignment film in each liquid crystal cell is arranged in a direction intersecting the direction of the extension of the strip electrodes, which is also the same as in the first embodiment.

[0207] Thus, for the liquid crystal light control element 102 involved in the fifth structure, the strip electrode configurations of the first liquid crystal cell 10 and the second liquid crystal cell 20 are the same as those of the fifth liquid crystal cell 50 and the sixth liquid crystal cell 60. For these liquid crystal cells, the third liquid crystal cell 30 and the fourth liquid crystal cell 40 are configured with their strip electrode configuration rotated by 90 degrees. This embodiment can also be described as... Figure 9 , Figure 10The modified example of the first embodiment shown further includes a structure in which two liquid crystal cells are stacked on the incident side. Furthermore, these additional liquid crystal cells can be considered to be the same liquid crystal cells as the third and fourth liquid crystal cells mentioned in the modified example of the first embodiment, and are arranged in the same orientation as these liquid crystal cells.

[0208] Figure 17 Similar to the first embodiment, the electrodes to which a control signal is applied and which form a transverse electric field are shown by cross-sectional lines. Furthermore, Figure 17 The table is inserted to indicate the state of the polarization components of light containing the first polarization component PL1 and the second polarization component PL2 as they pass through the first electrode, the liquid crystal layer, and the second electrode of each liquid crystal cell, using terms such as transmission, optical rotation, and diffusion.

[0209] Table 5 shows the... Figure 17 The control signals applied to each liquid crystal cell of the liquid crystal light control element 102 involved in the fifth structure shown.

[0210] [Table 5]

[0211]

[0212] As shown in Table 5, in each liquid crystal cell of the liquid crystal light control element 102 involved in the fifth structure, rectangular wave control signals A and B are applied to the first electrode (first strip electrode, second strip electrode) on the first substrate side (light incident side), and a constant voltage control signal E is applied to the second electrode (third strip electrode, fourth strip electrode) on the second substrate side (light emitting side). That is, Figure 17 The liquid crystal light control element 102 involved in the fifth structure shown applies control signals A and B to the first electrode of each liquid crystal cell and applies control signal E to the second electrode, generating a lateral electric field only on the first substrate side.

[0213] Next, the states of light diffusion, rotation, and transmission incident on the liquid crystal light control element 102 involved in the fifth structure will be described. In the fifth structure, the initial state of the first polarization component PL1 (the state immediately preceding the incident on the liquid crystal light control element 102) is also set to s-polarization, and the initial state of the second polarization component PL2 is set to p-polarization.

[0214] exist Figure 17Focusing on the first polarization component PL1, the first polarization component PL1 is incident on the first liquid crystal cell 10 in an s-polarized state. The s-polarized PL1 incident on the first liquid crystal cell 10 does not diffuse through the first electrode E11, but becomes p-polarized with a 90-degree optical rotation in the first liquid crystal layer LC1, and does not diffuse through the second electrode E12, but exits from the first liquid crystal cell 10. The p-polarized PL1 incident on the second liquid crystal cell 20 diffuses along the Y-axis through the first electrode E21, becomes s-polarized with a 90-degree optical rotation in the second liquid crystal layer LC2, and does not diffuse through the second electrode E22, but exits from the second liquid crystal cell 20. The s-polarized PL1 incident on the third liquid crystal cell 30 diffuses along the X-axis through the first electrode E31, becomes p-polarized with a 90-degree optical rotation in the third liquid crystal layer LC3, and does not diffuse through the second electrode E32, but exits from the third liquid crystal cell 30. The first polarization component PL1 (p-polarized) incident on the fourth liquid crystal cell 40 does not diffuse through the first electrode E41, but becomes s-polarized with a 90-degree optical rotation in the fourth liquid crystal layer LC4, and does not diffuse through the second electrode E42, but is emitted from the fourth liquid crystal cell 40. The first polarization component PL1 (s-polarized) incident on the fifth liquid crystal cell 50 does not diffuse through the first electrode E51, but becomes p-polarized with a 90-degree optical rotation in the fifth liquid crystal layer LC5, and does not diffuse through the second electrode E52, but is emitted from the fifth liquid crystal cell 50. The first polarization component PL1 (p-polarized) incident on the sixth liquid crystal cell 60 diffuses in the Y-axis direction through the first electrode E61, becomes s-polarized with a 90-degree optical rotation in the sixth liquid crystal layer LC6, and does not diffuse through the second electrode E62, but is emitted from the sixth liquid crystal cell 60. Thus, the first polarization component PL1 (s-polarization) incident on the liquid crystal light control element 102 involved in the fifth structure undergoes one diffusion in the X-axis direction and two diffusions in the Y-axis direction, and is emitted in an s-polarized state after six optical rotations in the liquid crystal layer.

[0215] exist Figure 17In this context, we focus on the second polarization component PL2. The second polarization component PL2, in a p-polarized state, is incident on the first liquid crystal cell 10. The p-polarized PL2 incident on the first liquid crystal cell 10 diffuses along the Y-axis through the first electrode E11, becomes s-polarized with a 90-degree optical rotation in the first liquid crystal layer LC1, does not diffuse through the second electrode E12, and is emitted from the first liquid crystal cell 10. The s-polarized PL2 incident on the second liquid crystal cell 20 does not diffuse through the first electrode E21, becomes p-polarized with a 90-degree optical rotation in the second liquid crystal layer LC2, does not diffuse through the second electrode E22, and is emitted from the second liquid crystal cell 20. The p-polarized PL2 incident on the third liquid crystal cell 30 does not diffuse through the first electrode E31, becomes s-polarized with a 90-degree optical rotation in the third liquid crystal layer LC3, does not diffuse through the second electrode E32, and is emitted from the third liquid crystal cell 30. The second polarization component PL2 (s-polarized) incident on the fourth liquid crystal cell 40 diffuses along the X-axis through the first electrode E41, becomes p-polarized with a 90-degree optical rotation in the fourth liquid crystal layer LC4, does not diffuse through the second electrode E42, and is emitted from the fourth liquid crystal cell 40. The second polarization component PL2 (p-polarized) incident on the fifth liquid crystal cell 50 diffuses along the Y-axis through the first electrode E51, becomes s-polarized with a 90-degree optical rotation in the fifth liquid crystal layer LC5, does not diffuse through the second electrode E52, and is emitted from the fifth liquid crystal cell 50. The second polarization component PL2 (s-polarized) incident on the sixth liquid crystal cell 60 does not diffuse through the first electrode E61, becomes p-polarized with a 90-degree optical rotation in the sixth liquid crystal layer LC6, does not diffuse through the second electrode E62, and is emitted from the sixth liquid crystal cell 60. Thus, the second polarization component PL2 (p-polarization) incident on the liquid crystal light control element 102 involved in the fifth structure undergoes one diffusion in the X-axis direction and two diffusions in the Y-axis direction, and is emitted in an s-polarized state after six optical rotations in the liquid crystal layer.

[0216] In the fifth structure, the first polarization component PL1 diffuses in the Y-axis direction before optical rotation in the second liquid crystal cell 20 and the sixth liquid crystal cell 60, respectively, and diffuses in the X-axis direction before optical rotation in the third liquid crystal cell 30. The second polarization component PL2 diffuses in the Y-axis direction before optical rotation in the first liquid crystal cell 10 and the fifth liquid crystal cell 50, respectively, and diffuses in the X-axis direction before optical rotation in the third liquid crystal cell 30. Alternatively, in the fifth structure, the second electrodes E12, E22, E32, R42, E52, and E62 can also be... Figure 6 Electrodes in a planar (also called flat or full-surface) shape, as shown, or as... Figure 8 The diagram shows a structure without a second electrode.

[0217] 3-2. Structure 6

[0218] In the sixth structure, the liquid crystal light control element causes the polarization component to diffuse on the first electrode E11, E41, and E51 sides (light incident side) of the first liquid crystal cell 10, the fourth liquid crystal cell 40, and the fifth liquid crystal cell 50, and not diffuse on the second electrode E12, E42, and E52 sides (light emitting side), and not diffuse on the first electrode E21, E31, and E61 sides (light incident side) of the second liquid crystal cell 20, the third liquid crystal cell 30, and the sixth liquid crystal cell 60, but diffuses on the second electrode E22, E32, and E62 sides (light emitting side).

[0219] Figure 18 The diagram shows the electrode configuration in each liquid crystal cell of the liquid crystal light control element 102 involved in the sixth structure and the state when light incident on the liquid crystal light control element 102 passes through each liquid crystal cell. The configuration of the strip electrodes in each liquid crystal cell is the same as in the fifth structure.

[0220] Table 6 shows the... Figure 18 The control signals applied to each liquid crystal cell of the liquid crystal light control element 102 involved in the sixth structure shown.

[0221] [Table 6]

[0222]

[0223] As shown in Table 6, for the liquid crystal light control element 102 involved in the sixth structure, in the first liquid crystal cell 10, the fourth liquid crystal cell 40 and the fifth liquid crystal cell 50, control signals A and B are applied to the first electrodes E11, E41, E51 (first strip electrodes E11A, E41A, E51A, second strip electrodes E11B, E41B, E51B) on the light incident side, and control signal E is applied to the second electrodes E12, E42, E52 (third strip electrodes E12A, E42A, E52A, fourth strip electrodes E12B, E42B, E52B) on the light emission side after rotation. Furthermore, in the second liquid crystal unit 20, the third liquid crystal unit 30, and the sixth liquid crystal unit 60, control signals E are applied to the first electrodes E21, E31, and E61 (first strip electrodes E21A, E31A, E61A, second strip electrodes E21B, E31B, and E61B) on the light-incident side, and control signals A and B are applied to the second electrodes E22, E32, and E42 (third strip electrodes E22A, E32A, E42A, and fourth strip electrodes E22B, E32B, and E42B). That is, for Figure 18Regarding the liquid crystal light control element 102 involved in the sixth structure shown, a lateral electric field is generated on the side of the first substrate S11, S41, and S51 of the first liquid crystal cell 10, the fourth liquid crystal cell 40, and the fifth liquid crystal cell 50, while no lateral electric field is generated on the side of the second substrate S12, S42, and S52. In the second liquid crystal cell 20, the third liquid crystal cell 30, and the sixth liquid crystal cell 60, no lateral electric field is generated on the side of the first substrate S21, S31, and S61, while a lateral electric field is generated on the side of the second substrate S22, S32, and S62.

[0224] Next, the states of light diffusion, rotation, and transmission incident on the liquid crystal light control element 102 involved in the sixth structure will be described. In the sixth structure, the initial state of the first polarization component PL1 (the state immediately preceding the incident on the liquid crystal light control element 102) is also set to s-polarization, and the initial state of the second polarization component PL2 is set to p-polarization.

[0225] exist Figure 18Focusing on the first polarization component PL1, the first polarization component PL1 is incident on the first liquid crystal cell 10 in an s-polarized state. The s-polarized PL1 incident on the first liquid crystal cell 10 does not diffuse through the first electrode E11, but becomes p-polarized with a 90-degree optical rotation in the first liquid crystal layer LC1, and does not diffuse through the second electrode E12, but exits from the first liquid crystal cell 10. The p-polarized PL1 incident on the second liquid crystal cell 20 does not diffuse through the first electrode E21, but becomes s-polarized with a 90-degree optical rotation in the second liquid crystal layer LC2, diffuses along the X-axis through the second electrode E22, and exits from the second liquid crystal cell 20. The s-polarized PL1 incident on the third liquid crystal cell 30 does not diffuse through the first electrode E31, but becomes p-polarized with a 90-degree optical rotation in the third liquid crystal layer LC3, diffuses along the Y-axis through the second electrode E32, and exits from the third liquid crystal cell 30. The first polarization component PL1 (p-polarized) incident on the fourth liquid crystal cell 40 does not diffuse through the first electrode E41, but becomes s-polarized with a 90-degree optical rotation in the fourth liquid crystal layer LC4, and does not diffuse through the second electrode E42, and is emitted from the fourth liquid crystal cell 40. The first polarization component PL1 (s-polarized) incident on the fifth liquid crystal cell 50 does not diffuse through the first electrode E51, but becomes p-polarized with a 90-degree optical rotation in the fifth liquid crystal layer LC5, and does not diffuse through the second electrode E52, and is emitted from the fifth liquid crystal cell 50. The first polarization component PL1 (p-polarized) incident on the sixth liquid crystal cell 60 does not diffuse through the first electrode E61, but becomes s-polarized with a 90-degree optical rotation in the sixth liquid crystal layer LC6, diffuses along the X-axis through the second electrode E62, and is emitted from the sixth liquid crystal cell 60. Thus, the first polarization component PL1 (s-polarization) incident on the liquid crystal light control element 102 involved in the sixth structure undergoes two diffusions in the X-axis direction and one diffusion in the Y-axis direction after optical rotation, and is emitted in an s-polarized state after six optical rotations in the liquid crystal layer.

[0226] exist Figure 18In this context, we focus on the second polarization component PL2. The second polarization component PL2, in a p-polarized state, is incident on the first liquid crystal cell 10. The p-polarized PL2 incident on the first liquid crystal cell 10 diffuses along the Y-axis through the first electrode E11, becomes s-polarized with a 90-degree optical rotation in the first liquid crystal layer LC1, does not diffuse through the second electrode E12, and is emitted from the first liquid crystal cell 10. The s-polarized PL2 incident on the second liquid crystal cell 20 does not diffuse through the first electrode E21, becomes p-polarized with a 90-degree optical rotation in the second liquid crystal layer LC2, does not diffuse through the second electrode E22, and is emitted from the second liquid crystal cell 20. The p-polarized PL2 incident on the third liquid crystal cell 30 does not diffuse through the first electrode E31, becomes s-polarized with a 90-degree optical rotation in the third liquid crystal layer LC3, does not diffuse through the second electrode E32, and is emitted from the third liquid crystal cell 30. The second polarization component PL2 (s-polarized) incident on the fourth liquid crystal cell 40 diffuses along the X-axis through the first electrode E41, becomes p-polarized with a 90-degree optical rotation in the fourth liquid crystal layer LC4, does not diffuse through the second electrode E42, and is emitted from the fourth liquid crystal cell 40. The second polarization component PL2 (p-polarized) incident on the fifth liquid crystal cell 50 diffuses along the Y-axis through the first electrode E51, becomes s-polarized with a 90-degree optical rotation in the fifth liquid crystal layer LC5, does not diffuse through the second electrode E52, and is emitted from the fifth liquid crystal cell 50. The second polarization component PL2 (s-polarized) incident on the sixth liquid crystal cell 60 does not diffuse through the first electrode E61, becomes p-polarized with a 90-degree optical rotation in the second liquid crystal layer LC2, does not diffuse through the second electrode E62, and is emitted from the sixth liquid crystal cell 60. Thus, the second polarization component PL2 (p-polarization) incident on the liquid crystal light control element 102 involved in the sixth structure undergoes one diffusion in the X-axis direction and two diffusions in the Y-axis direction before optical rotation, and is emitted in a p-polarized state after five optical rotations in the liquid crystal layer.

[0227] In the sixth structure, the first polarization component PL1 diffuses in the X-axis direction after optical rotation in the second liquid crystal cell 20 and the fifth liquid crystal cell 50, and diffuses in the Y-axis direction after optical rotation in the third liquid crystal cell 30. The second polarization component PL2 diffuses in the Y-axis direction before optical rotation in the first liquid crystal cell 10 and the fifth liquid crystal cell 50, and diffuses in the X-axis direction before optical rotation in the third liquid crystal cell 30.

[0228] 3-3. Refer to Example 3

[0229] Figure 19The liquid crystal light control element according to Reference Example 3 is shown. In Reference Example 3, a control signal A is applied to the first strip electrode E11A on the first substrate S11 side of the first liquid crystal cell 10, a control signal B is applied to the second strip electrode E11B, a control signal A is applied to the third strip electrode E12A on the second substrate S12 side, and a control signal B is applied to the fourth strip electrode E12B. The same applies to the second liquid crystal cell 20, the third liquid crystal cell 30, the fourth liquid crystal cell 40, the fifth liquid crystal cell 50, and the sixth liquid crystal cell 60.

[0230] exist Figure 19 In the first liquid crystal cell 10, focusing on the first polarization component PL1, PL1 is incident in an s-polarized state. PL1 does not diffuse in the first liquid crystal cell 10, but instead becomes p-polarized in the first liquid crystal layer LC1 due to 90-degree optical rotation. PL1, in a p-polarized state, is incident in the second liquid crystal cell 20, diffuses along the Y-axis through the first electrode E21, becomes s-polarized in the second liquid crystal layer LC2 due to 90-degree optical rotation, and diffuses along the X-axis through the second electrode E22. PL1, in an s-polarized state, is incident in the third liquid crystal cell 30, diffuses along the X-axis through the first electrode E31, becomes p-polarized in the third liquid crystal layer LC3 due to 90-degree optical rotation, and diffuses along the Y-axis through the second electrode E32. The first polarization component PL1, in a p-polarized state, is incident on the fourth liquid crystal cell 40 without diffusion. It then undergoes a 90-degree optical rotation in the fourth liquid crystal layer LC4, becoming s-polarized and exiting. The first polarization component PL1, in an s-polarized state, is incident on the fifth liquid crystal cell 50 without diffusion. It then undergoes a 90-degree optical rotation in the fifth liquid crystal layer LC5, becoming p-polarized and exiting. The first polarization component PL1, in a p-polarized state, is incident on the sixth liquid crystal cell 60, diffuses along the Y-axis through the first electrode E61, becomes s-polarized in the sixth liquid crystal layer LC6 with a 90-degree optical rotation, and diffuses along the X-axis through the second electrode E62.

[0231] exist Figure 19In the process, focusing on the second polarization component PL2, the second polarization component PL2 is incident on the first liquid crystal cell 10 in a p-polarized state. The second polarization component PL2 diffuses along the Y-axis through the first electrode E11, becomes s-polarized in the first liquid crystal layer LC1 by 90 degrees of optical rotation, and diffuses along the X-axis through the second electrode E12. The second polarization component PL2, in a s-polarized state, is incident on the second liquid crystal cell 20 without diffusion, but becomes p-polarized in the second liquid crystal layer LC2 by 90 degrees of optical rotation and is emitted. The second polarization component PL2, in a p-polarized state, is incident on the third liquid crystal cell 30 without diffusion, but becomes s-polarized in the third liquid crystal layer LC3 by 90 degrees of optical rotation and is emitted. The second polarization component PL2, in a s-polarized state, is incident on the fourth liquid crystal cell 40, diffuses along the X-axis through the first electrode E41, becomes p-polarized in the fourth liquid crystal layer LC4 by 90 degrees of optical rotation, and diffuses along the Y-axis through the second electrode E42. The second polarization component PL2, in a p-polarized state, is incident on the fifth liquid crystal cell 50. It diffuses along the Y-axis through the first electrode E51, and becomes s-polarized by 90 degrees in the fifth liquid crystal layer LC5. It then diffuses along the X-axis through the second electrode E52. The second polarization component PL2, in an s-polarized state, is incident on the sixth liquid crystal cell 60 without diffusion. Instead, it becomes p-polarized by 90 degrees in the sixth liquid crystal layer LC6 and is emitted.

[0232] Thus, for the liquid crystal light control element involved in Reference Example 3, the first polarization component PL1 diffuses in the second liquid crystal cell 20, the third liquid crystal cell 30 and the sixth liquid crystal cell 60 in the X-axis direction and the Y-axis direction, respectively, and the second polarization component PL2 diffuses in the first liquid crystal cell 10, the fourth liquid crystal cell 40 and the fifth liquid crystal cell 50 in the X-axis direction and the Y-axis direction, respectively.

[0233] 3-4.Angle characteristics

[0234] Figure 20 A graph showing the brightness-angle characteristics of the liquid crystal light control element 102 involved in the fifth and sixth structures is provided. Furthermore, Figure 20 The characteristics of Reference Example 3 are shown in this diagram. Additionally, with... Figure 12A same, Figure 20 The horizontal axis of the chart shows the polar angle, and the vertical axis shows the brightness when the brightness at the center (polar angle 0 degrees) is normalized to 100%.

[0235] exist Figure 20As shown in the diagram, the fifth structure of the liquid crystal light control element 102 exhibits the same brightness (100%) as the center brightness (0 degrees polar angle) within a polar angle range of ±30 degrees. While this brightness decreases by approximately 5% within a polar angle range of ±30 to ±45 degrees, a constant brightness distribution is achieved within this range. The fifth structure demonstrates a substantially flat intensity distribution within a constant polar angle range by employing a structure that allows each polarization component to diffuse before optical rotation and not diffuse after optical rotation in the liquid crystal layer. Furthermore, it is evident that compared to the first and third structures, the brightness is higher, and the range of polar angles within which the brightness distribution remains constant is larger.

[0236] The characteristics of the sixth structure of the liquid crystal light control element 102 exhibit the following trend: brightness decreases as the polar angle increases towards both the positive and negative directions from the center (polar angle 0 degrees). Within the polar angle ranges of +30 to +45 degrees and -30 to -45 degrees, the proportion of brightness reduction tends to decrease. In the sixth structure, the diffusion of the first polarization component PL1 occurs after optical rotation in the liquid crystal layer, while the diffusion of the second polarization component PL2 occurs before optical rotation. Compared to the fifth structure, the sixth structure generally exhibits lower brightness, but shows a different distribution in the angular characteristics of brightness.

[0237] Thus, if the fifth structure is compared with the sixth structure, it is shown that: in the fifth structure, the first polarization component and the second polarization component each undergo one pre-diffusion in the X-axis direction during the process of passing through the liquid crystal light control element 102; on the other hand, in the sixth structure, the first polarization component undergoes two post-diffusions in the X-axis direction, and the second polarization component undergoes one pre-diffusion in the X-axis direction. The two pre-diffusions suppress brightness reduction more than the one pre-diffusion and the two post-diffusions, and the polar angle range for maintaining constant brightness is larger.

[0238] Comparing structure 5 with structures 1 and 5, the brightness is relatively higher, and the range of constant polar angles is larger. Structure 6 exhibits the same trend when compared with structures 2 and 4. One reason for this change in properties is believed to be that the first polarization component PL1 and the second polarization component PL2 diffuse more times than structures 1 and 2.

[0239] The liquid crystal light control element shown in Reference Example 3 exhibits the following trend: the intensity of the brightness distribution is greatest at the polar angle of 0 degrees, and decreases linearly as the polar angle increases in both the positive and negative directions (i.e., the left and right directions). It can be seen that the liquid crystal light control element involved in Reference Example 3 is the same as that in Reference Examples 1 and 2, achieving a brightness distribution that decreases linearly in the polar angle direction by diffusing each polarization component in the liquid crystal layer.

[0240] More specifically, in Reference Example 3, the first polarization component undergoes one pre-diffusion in the X-axis direction, but subsequent diffusion in the Y-axis direction within the immediately following identical liquid crystal cell (the third liquid crystal cell). Furthermore, the second polarization component undergoes one pre-diffusion in the X-axis direction, but subsequent diffusion in the immediately preceding identical liquid crystal cell (the fourth liquid crystal cell). Further, in Reference Example 3, the first polarization component undergoes one pre-diffusion in the Y-axis direction within the second and sixth liquid crystal cells, but subsequent diffusion in the X-axis direction within the immediately following identical liquid crystal cell. Furthermore, the second polarization component undergoes one pre-diffusion in the Y-axis direction within the first and fifth liquid crystal cells, and subsequent diffusion in the X-axis direction within the immediately following identical liquid crystal cell. That is, in Reference Example 3, the first polarization component undergoes one pre-diffusion and two subsequent diffusions in the X-axis direction, but both are accompanied by diffusion in the Y-axis direction within the same liquid crystal cell. Furthermore, in Reference Example 2, the second polarization component undergoes one pre-diffusion and two post-diffusions in the X-axis direction, but both are accompanied by diffusion in the Y-axis direction within the same liquid crystal cell. According to Figure 20 It is shown that if diffusion occurs before and after light rotation within the same liquid crystal cell, even if the number of diffusions is the same, the brightness decreases monotonically as the polar angle increases compared to the case where diffusion occurs only through diffusion (structure 5).

[0241] In addition, according to Figure 20 In the fifth structure, the half-value width is the same as that of Reference Example 3, and compared with Reference Example 3, the brightness within the half-value width is increased and kept constant. In the sixth structure, the half-value width is the same as that of Reference Example 3, and compared with Reference Example 3, the brightness within the half-value width is decreased and kept constant.

[0242] According to this embodiment, in a liquid crystal cell with a 6-level configuration, by employing a structure in which each polarization component diffuses before optical rotation in the liquid crystal layer and does not diffuse after optical rotation, a substantially flat intensity distribution can be obtained within a constant range of polar angles. Furthermore, in a liquid crystal cell with a 6-level configuration, by employing a structure in which each polarization component diffuses before or after optical rotation in the liquid crystal layer and does not diffuse before or after optical rotation within a single liquid crystal cell, a substantially flat intensity distribution can also be obtained within a constant range of polar angles.

[0243] [Fourth Implementation]

[0244] Figure 21 A perspective view of an illumination device 100 according to an embodiment of the present invention is shown. The illumination device 100 includes a liquid crystal light control element 102 and a circuit board 104. The liquid crystal light control element 102 adopts the structure shown in embodiments 1 to 4. Figure 21An example is shown where the liquid crystal light control element 102 is composed of a first liquid crystal unit 10, a second liquid crystal unit 20, a third liquid crystal unit 30, and a fourth liquid crystal unit 40. A transparent adhesive layer (not shown) is provided between the first liquid crystal unit 10 and the second liquid crystal unit 20, between the second liquid crystal unit 20 and the third liquid crystal unit 30, and between the third liquid crystal unit 30 and the fourth liquid crystal unit 40. The liquid crystal light control element 102 has a structure in which adjacent liquid crystal units are bonded to each other through the transparent adhesive layer.

[0245] The circuit board 104 includes a circuit for driving the liquid crystal light control element 102. A first liquid crystal cell 10 is connected to the circuit board 104 via a first flexible wiring substrate F1, a second liquid crystal cell 20 is connected to the circuit board 104 via a second flexible wiring substrate F2, a third liquid crystal cell 30 is connected to the circuit board 104 via a third flexible wiring substrate F3, and a fourth liquid crystal cell 40 is connected to the circuit board 104 via a fourth flexible wiring substrate F4. The circuit board 104 outputs control signals to each liquid crystal cell via the flexible wiring substrates to control the orientation state of the liquid crystal.

[0246] Figure 1 The illumination device 100 shown has a light source 106 disposed on the back side of the liquid crystal light control element 102. The illumination device 100 is configured such that light emitted from the light source 106 passes through the liquid crystal light control element 102 and exits near the front side of the figure. The liquid crystal light control element 102 has a first liquid crystal cell 10, a second liquid crystal cell 20, a third liquid crystal cell 30, and a fourth liquid crystal cell 40 disposed sequentially from the side of the light source 106.

[0247] Alternatively, the light source 106 may include a white light source, with optical elements such as lenses disposed between the white light source and the liquid crystal light control element 102 as needed. The white light source is a light source that emits light close to natural light, or it may be a light source that emits dimmed light such as daylight color or bulb color. The light source 106 is preferably composed of a light source with a narrow light distribution range, and for example, it is preferably composed of a structure that combines an LED light source with reflectors, lenses, etc.

[0248] As shown in embodiments 1 to 4, the lighting device 100 according to this embodiment can control the intensity distribution of light emitted from the light source 106 via the liquid crystal light control element 102. That is, by inputting a control signal to the liquid crystal light control element 102, the intensity distribution of the illumination light in the polar angle direction can be controlled. With the lighting device 100 according to this embodiment, illumination with adjusted illuminance within the illumination surface can be achieved.

[0249] Explanation of reference numerals in the attached figures

[0250] 10...1st liquid crystal unit; 20...2nd liquid crystal unit; 30...3rd liquid crystal unit; 40...4th liquid crystal unit; 50...5th liquid crystal unit; 60...6th liquid crystal unit; 100...lighting device; 102...liquid crystal light control element; 104...circuit board; 106...light source; AL11...1st alignment film; AL12...2nd alignment film; E11...1st electrode; E12...2nd electrode; E11A...1st strip electrode; E11B...2nd strip electrode; E12A...3rd strip electrode; E12B...4th strip electrode; F1...1st flexible wiring substrate; F2...2nd flexible wiring substrate; F3...3rd flexible wiring substrate; F4...4th flexible wiring substrate Substrate; LC1...1st liquid crystal layer; LC2...2nd liquid crystal layer; LC3...3rd liquid crystal layer; LC4...4th liquid crystal layer; LC5...5th liquid crystal layer; LC6...6th liquid crystal layer; LCM...liquid crystal molecule; PE11...1st power supply line; PE12...2nd power supply line; PE13...3rd power supply line; PE14...4th power supply line; PE15...5th power supply line; PE16...6th power supply line; PT11...1st power supply terminal; PT12...2nd power supply terminal; SE...sealant; S11...1st substrate; S12...2nd substrate; T11...1st connection terminal; T12...2nd connection terminal; T13...3rd connection terminal; T14...4th connection terminal.

Claims

1. A liquid crystal light control element, comprising a plurality of liquid crystal cells stacked together. Each of the plurality of liquid crystal cells includes: A first substrate and a second substrate opposite to the first substrate; A first electrode and a second electrode having a strip pattern are disposed on the first substrate; The third electrode and the fourth electrode, which are disposed on the second substrate and have a strip pattern, are present. A first alignment film disposed on the first substrate and a second alignment film disposed on the second substrate; and The liquid crystal layer between the first substrate and the second substrate, The plurality of liquid crystal cells are arranged in an overlapping configuration. The strip patterns of the first electrode and the second electrode are arranged alternately. The strip patterns of the third electrode and the fourth electrode are arranged alternately. The extension directions of the strip patterns in the first and second electrodes are intersected with the extension directions of the strip patterns in the third and fourth electrodes. The orientation direction of the first orientation film is set to intersect with the extension direction of the strip pattern of the first electrode and the second electrode. The orientation direction of the second orientation film is set to intersect with the orientation direction of the first orientation film. Each of the plurality of liquid crystal cells is configured such that light is incident from the side of the first substrate. The plurality of liquid crystal units are stacked in the order of the first liquid crystal unit, the second liquid crystal unit, the third liquid crystal unit, and the fourth liquid crystal unit, from the incident side of light toward the emitted side. The extending directions of the first electrode and the second electrode of the first liquid crystal cell and the second liquid crystal cell are configured to be parallel to the first direction. The extending directions of the first electrode and the second electrode of the third liquid crystal cell and the fourth liquid crystal cell are configured to be parallel to a second direction that intersects the first direction. A voltage is applied to the first liquid crystal cell and the fourth liquid crystal cell to make the first electrode and the second electrode have the same potential, and to form a transverse electric field between the third electrode and the fourth electrode. The second and third liquid crystal cells are subjected to a voltage to form a transverse electric field between the first and second electrodes, and the third and fourth electrodes are at the same potential.

2. A liquid crystal light control element, comprising a plurality of liquid crystal cells stacked together. Each of the plurality of liquid crystal cells includes: A first substrate and a second substrate opposite to the first substrate; A first electrode and a second electrode having a strip pattern are disposed on the first substrate; The third electrode and the fourth electrode, which are disposed on the second substrate and have a strip pattern, are present. A first alignment film disposed on the first substrate and a second alignment film disposed on the second substrate; and The liquid crystal layer between the first substrate and the second substrate, The plurality of liquid crystal cells are arranged in an overlapping configuration. The strip patterns of the first electrode and the second electrode are arranged alternately. The strip patterns of the third electrode and the fourth electrode are arranged alternately. The extension directions of the strip patterns in the first and second electrodes are intersected with the extension directions of the strip patterns in the third and fourth electrodes. The orientation direction of the first orientation film is set to intersect with the extension direction of the strip pattern of the first electrode and the second electrode. The orientation direction of the second orientation film is set to intersect with the orientation direction of the first orientation film. Each of the plurality of liquid crystal cells is configured such that light is incident from the side of the first substrate. The plurality of liquid crystal units are stacked in the order of the first liquid crystal unit, the second liquid crystal unit, the third liquid crystal unit, the fourth liquid crystal unit, and the fifth liquid crystal unit, from the incident side of light toward the emission side. The extending directions of the first electrode and the second electrode of the second liquid crystal unit and the third liquid crystal unit are configured to be parallel to the first direction. The extending directions of the first electrode and the second electrode of the first liquid crystal cell, the fourth liquid crystal cell, and the fifth liquid crystal cell are configured to be parallel to a second direction that intersects the first direction.

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

4. A liquid crystal light control element, comprising a plurality of liquid crystal cells stacked together. Each of the plurality of liquid crystal cells includes: A first substrate and a second substrate opposite to the first substrate; A first electrode and a second electrode having a strip pattern are disposed on the first substrate; The third electrode and the fourth electrode, which are disposed on the second substrate and have a strip pattern, are present. A first alignment film disposed on the first substrate and a second alignment film disposed on the second substrate; and The liquid crystal layer between the first substrate and the second substrate, The plurality of liquid crystal cells are arranged in an overlapping configuration. The strip patterns of the first electrode and the second electrode are arranged alternately. The strip patterns of the third electrode and the fourth electrode are arranged alternately. The extension directions of the strip patterns in the first and second electrodes are intersected with the extension directions of the strip patterns in the third and fourth electrodes. The orientation direction of the first orientation film is set to intersect with the extension direction of the strip pattern of the first electrode and the second electrode. The orientation direction of the second orientation film is set to intersect with the orientation direction of the first orientation film. Each of the plurality of liquid crystal cells is configured such that light is incident from the side of the first substrate. The plurality of liquid crystal units are stacked in the order of the first liquid crystal unit, the second liquid crystal unit, the third liquid crystal unit, the fourth liquid crystal unit, the fifth liquid crystal unit, and the sixth liquid crystal unit, from the incident side of light toward the emission side. The extending directions of the first electrode and the second electrode of the first liquid crystal cell and the second liquid crystal cell are configured to be parallel to the second direction. The extending directions of the first electrode and the second electrode of the third liquid crystal cell and the fourth liquid crystal cell are configured to be parallel to the first direction that intersects the second direction. The extending directions of the first electrode and the second electrode of the fifth liquid crystal cell and the sixth liquid crystal cell are configured to be parallel to the second direction.

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

6. The liquid crystal light control element according to any one of claims 1 to 5, wherein, The liquid crystal layer is a twisted nematic liquid crystal.

7. A lighting device, characterized in that, The invention includes a liquid crystal light control element and a light source as described in any one of claims 1 to 5, wherein the liquid crystal light control element is disposed in the optical path of light emitted from the light source.

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