Patent Publication Number: US-2022235918-A1

Title: Light control device and illumination device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation Application of PCT Application No. PCT/JP2020/038684, filed Oct. 13, 2020 and based upon and claiming the benefit of priority from Japanese Patent Application No. 2019-210699, filed Nov. 21, 2019, the entire contents of all of which are incorporated herein by reference. 
    
    
     FIELD 
     Embodiments described herein relate generally to a light control device and an illumination device. 
     BACKGROUND 
     In recent years, various types of liquid crystal lenses configured to control paths of the light emitted from a light source have been proposed. For example, there is a liquid crystal lens including a plurality of arcuate electrodes and lead electrodes connected to the arcuate electrodes. For another example, there is a technique of layering a plurality of liquid crystal lenses in which strip electrodes of one liquid crystal lens and strip electrodes of the other liquid crystal lens overlap with each other in a shifted manner, such that the strip electrodes are arranged in a pseud fine structure. The lead electrode connected to each of the strip electrodes will be disposed in an effective area where the liquid crystal lens is formed, and it may cause disturbance in the electric field to form the liquid crystal lens. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram illustrating an example of the structure of an illumination device  100  of an embodiment. 
         FIG. 2  is a cross-sectional view of a structural example of a first liquid crystal cell  10 . 
         FIG. 3  is a diagram illustrating a liquid crystal lens LL 1  formed in the first liquid crystal cell  10 . 
         FIG. 4  is a plan view illustrating a structural example of the first liquid crystal cell  10 . 
         FIG. 5  is a diagram illustrating a light modulation effect in each segment of a first control electrode E 1 . 
         FIG. 6  is a diagram illustrating a structural example of a light control device  200 . 
         FIG. 7  is a diagram illustrating another structural example of the light control device  200 . 
         FIG. 8  is a diagram illustrating another structural example of the light control device  200 . 
         FIG. 9  is a cross-sectional view of another structural example of first and second liquid crystal cells  10  and  20  of the light control device  200 . 
         FIG. 10  is a plan view illustrating another structural example of a second control electrode E 2 . 
         FIG. 11  is a diagram illustrating another structural example of the light control device  200 . 
         FIG. 12  is a diagram illustrating another structural example of the light control device  200 . 
         FIG. 13  is a diagram illustrating another structural example of the light control device  200 . 
         FIG. 14  is a diagram illustrating another structural example of the light control device  200 . 
     
    
    
     DETAILED DESCRIPTION 
     In general, according to one embodiment, a light control device includes: a first substrate including a plurality of first control electrodes disposed in an effective area, and a plurality of feed lines disposed in a peripheral area; a second substrate; and a first liquid crystal layer held between the first substrate and the second substrate, wherein the first control electrodes are transparent electrodes, each of the first control electrodes includes, in the effective area, first segments crossing a first direction at a first angle, second segments crossing the first direction at a second angle, and third segments crossing the first direction at a third angle, each of the first control electrodes extends in the peripheral area, and is electrically connected to one of the feed lines, and the first to third angles are different from each other. 
     According to another embodiment, a light control device includes: a first liquid crystal cell including a first control electrode; and a second liquid crystal cell including a second control electrode, wherein the second liquid crystal cell overlaps the first liquid crystal cell, the first control electrode and the second control electrode are transparent electrodes, the first control electrode includes first segments crossing a first direction at a first angle, second segments crossing the first direction at a second angle, and third segments crossing the first direction at a third angle, the second control electrode includes fourth segments crossing the first direction at a fourth angle, fifth segments crossing the first direction at a fifth angle, and sixth segments crossing the first direction at a sixth angle, and the first to sixth angles are different from each other. 
     According to another embodiment, a light control device includes: a first substrate including a plurality of first control electrodes disposed in a first effective area, and a plurality of second control electrodes disposed in a second effective area which is adjacent to the first effective area; a second substrate; and a first liquid crystal layer held between the first substrate and the second substrate, wherein the first control electrodes and the second control electrodes are transparent electrodes, the first control electrodes are apart from the second control electrodes, each of the first control electrodes includes first segments crossing a first direction at a first angle, second segments crossing the first direction at a second angle, and third segments crossing the first direction at a third angle, each of the second control electrodes includes fourth segments crossing the first direction at a fourth angle, fifth segments crossing the first direction at a fifth angle, and sixth segment crossing the first direction at a sixth angle, and the first to sixth angles are different from each other. 
     According to another embodiment, an illumination device includes: a light source; and a light control device configured to control light emitted from the light source, wherein the light control device includes a first substrate including a plurality of first control electrodes disposed in an effective area and a plurality of feed lines disposed in a peripheral area, a second substrate, and a first liquid crystal layer held between the first substrate and the second substrate, wherein the first control electrodes are transparent electrodes, each of the first control electrodes includes, in the effective area, first segments crossing a first direction at a first angle, second segments crossing the first direction at a second angle, and third segments crossing the first direction at a third angle, each of the first control electrodes extends in the peripheral area, and is electrically connected to one of the feed lines, and the first to third angles are different from each other. 
     According to another embodiment, an illumination device includes: a light source; and a light control device configured to control light emitted from the light source, wherein the light control device includes a first liquid crystal cell including a first control electrode and a second liquid crystal cell including a second control electrode, wherein the second liquid crystal cell overlaps the first liquid crystal cell, the first control electrode and the second control electrode are transparent electrodes, the first control electrode includes first segments crossing a first direction at a first angle, second segments crossing the first direction at a second angle, and third segments crossing the first direction at a third angle, the second control electrode includes fourth segments crossing the first direction at a fourth angle, fifth segments crossing the first direction at a fifth angle, and sixth segments crossing the first direction at a sixth angle, and the first to sixth angles are different from each other. 
     According to another embodiment, an illumination device includes: a light source; and a light control device configured to control light emitted from the light source, wherein the light control device includes a first substrate including a plurality of first control electrodes disposed in a first effective area and a plurality of second control electrodes disposed in a second effective area which is adjacent to the first effective area, a second substrate, and a first liquid crystal layer held between the first substrate and the second substrate, wherein the first control electrodes and the second control electrodes are transparent electrodes, the first control electrodes are apart from the second control electrodes, each of the first control electrodes includes first segments crossing a first direction at a first angle, second segments crossing the first direction at a second angle, and third segments crossing the first direction at a third angle, each of the second control electrodes includes fourth segments crossing the first direction at a fourth angle, fifth segments crossing the first direction at a fifth angle, and sixth segments crossing the first direction at a sixth angle, and the first to sixth angles are different from each other. 
     According to an embodiment, a light control device and an illumination device which can reduce an ineffective area can be presented. 
     Embodiments will be described hereinafter with reference to the accompanying drawings. The disclosure is merely an example, and proper changes within the spirit of the invention, which are easily conceivable by a skilled person, are included in the scope of the invention as a matter of course. In addition, in some cases, in order to make the description clearer, the widths, thicknesses, shapes, etc., of the respective parts are schematically illustrated in the drawings, compared to the actual modes. However, the schematic illustration is merely an example, and adds no restrictions to the interpretation of the invention. Besides, in the specification and drawings, the same or similar elements as or to those described in connection with preceding drawings or those exhibiting similar functions are denoted by like reference numerals, and a detailed description thereof is omitted unless otherwise necessary. 
       FIG. 1  is a diagram schematically showing a configuration example of an illumination device  100  according to one embodiment. In this embodiment, a first direction X, a second direction Y and a third direction Z are orthogonal to each other, but they may intersect at an angle other than 90°. In the following descriptions, viewing from above downward onto an X-Y plane defined by the first direction X and the second direction Y is referred to as plan view. 
     The illumination device  100  includes a light source LS, a light control device  200  configured to control the light emitted from the light source LS, and a controller CT. The light source LS emits light toward the third direction Z. The light emitted from the light source LS is, for example, natural light (non-polarized light). The light control device  200  overlaps the light source LS in the third direction Z. The light control device  200  includes a first liquid crystal cell  10  and a second liquid crystal cell  20 . The first liquid crystal cell  10  and the second liquid crystal cell  20  may have substantially the same elements, or may have different elements. 
     The first liquid crystal cell  10  includes a first substrate SUB 1 , a second substrate SUB 2 , and a first liquid crystal layer LC 1 . The first substrate SUB 1  includes an insulating substrate  11 , a plurality of first control electrodes E 1  disposed on the insulating substrate  11 , and an alignment film AL 1  covering the first control electrodes E 1 . The second substrate SUB 2  includes an insulating substrate  12 , a first common electrode C 1  disposed on the insulating substrate  12 , and an alignment film AL 2  covering the first common electrode C 1 . The first common electrode C 1  is opposed to the first control electrodes E 1 . 
     The second liquid crystal cell  20  includes a third substrate SUB 3 , a fourth substrate SUB 4 , and a second liquid crystal layer LC 2 . The third substrate SUB 3  includes an insulating substrate  21 , a plurality of second control electrodes E 2  disposed on the insulating substrate  21 , and an alignment film AL 3  covering the second control electrodes E 2 . The fourth substrate SUB 4  includes an insulating substrate  22 , a second control electrode C 2  disposed on the insulating substrate  22 , and an alignment film AL 4  covering the second common electrode C 2 . The second common electrode C 2  is opposed to the second control electrodes E 2 . 
     The insulating substrates  11  and  12 , and insulating substrates  21  and  22  are transparent substrates such as glass or resin substrates. 
     The first control electrodes E 1 , second control electrodes E 2 , first common electrode C 1 , and second common electrode C 2  are transparent electrodes formed of transparent conductive materials such as indium tin oxide (ITO) and indium zinc oxide (IZO). The specific shapes of the first control electrodes E 1  and the second control electrodes E 2  will be described later. 
     The alignment films AL 1  to AL 4  are horizontal alignment films with the alignment restriction force which is substantially parallel to the X-Y plane. For example, alignment processing direction AD 1  of the alignment film AL 1  and alignment processing direction AD 2  of the alignment film AL 2  are both parallel to the first direction X and are opposite to each other. Furthermore, alignment processing direction AD 3  of the alignment film AL 3  and alignment processing direction AD 4  of the alignment film AL 4  are both parallel to the second direction Y and are opposite to each other. The alignment processing may be a rubbing processing or an optical-alignment processing. 
     The first liquid crystal layer LC 1  is held by the alignment films AL 1  and AL 2  between the first substrate SUB 1  and the second substrate SUB 2 , and includes liquid crystal molecules LM 1  initially aligned along the first direction X. The second liquid crystal layer LC 2  is held by the alignment films AL 3  and AL 4  between the third substrate SUB 3  and the fourth substrate SUB 4 , and includes liquid crystal molecules LM 2  initially aligned along the second direction Y. That is, the initial alignment direction of the liquid crystal molecules LM 1  intersects the initial alignment direction of the liquid crystal molecules LM 2 . Note that, the initial alignment corresponds to the alignment of the liquid crystal molecules when no voltage is applied to the liquid crystal layer, or the alignment of the liquid crystal molecules due to the alignment restriction force by the pair of alignment films holding the liquid crystal layer. The first liquid crystal layer LC 1  and the second liquid crystal layer LC 2  have, for example, positive dielectric constant anisotropy, or may have negative dielectric constant anisotropy. 
     The second liquid crystal cell  20  overlaps on top of the first liquid crystal cell  10  in the third direction Z. The insulating substrate  12  and the insulating substrate  21  are adhered to each other by a transparent adhesive layer AD. The refractive index of the adhesive layer AD is equivalent to the refractive index of the insulating substrates  12  and  21 . On the other hand, the outer surface  11 A of the insulating substrate  11  and the outer surface  22 A of the insulating substrate  22  are in contact with an air layer, respectively. The outer surface  22 A may be provided with, if necessary, a UV cut layer to inhibit the degradation of the liquid crystal layer due to external light, a diffusion layer to mitigate the effect of uneven alignment of the liquid crystal molecules, or an outer surface  22 A may be matte treated. 
     The controller CT includes a light source controller LCT, and voltage controllers DCT 1  and DCT 2 . The light source controller LCT controls a current value that drives the light source LS, for example. The voltage controller DCT 1  controls a voltage to be applied to the first control electrodes E 1  and the first common electrode C 1  in the first liquid crystal cell  10 . The voltage controller DCT 2  controls the voltage to be applied to the second control electrodes E 2  and the second common electrode C 2  in the second liquid crystal cell  20 . 
     In such a light control device  200 , the light source LS is provided to be opposed to the outer surface  11 A of the insulating substrate  11 . That is, the outer surface  11 A functions as an incident surface of the illumination light. The first liquid crystal cell  10  mainly modulates the first polarization component (P polarization) POL 1  of the incident light. In the coordinate system of  FIG. 1 , the first polarization component POL 1  is linearly polarized light with the oscillation plane in the first direction X. The second liquid crystal cell  20  mainly modulates the second polarization component (S polarization) POL 2  passing through the first liquid crystal cell  10 . The second polarization component POL 2  is linearly polarized light with the oscillation plane in the second direction Y. 
     Modulation here refers to the refraction, convergence, or divergence of polarized light components passing through the liquid crystal layer by a refractive index distribution type lens (hereinafter referred to as liquid crystal lens) formed in the liquid crystal layer. The degree of convergence or divergence (modulation rate) is controlled by the voltage applied to the liquid crystal layer. That is, the modulation rate of the first polarization component in the first liquid crystal cell  10  is controlled by the voltage controller DCT 1 , and the modulation rate of the second polarization component in the second liquid crystal cell  20  is controlled by the voltage controller DCT 2 . The voltage controller DCT 1  and the voltage controller DCT 2  may be controlled by the same voltage conditions, or by different voltage conditions. Furthermore, each of the voltage controllers DCT 1  and DCT 2  may be controlled under the voltage conditions to form a convex type liquid crystal lens, a concave type liquid crystal lens, or any other shape of liquid crystal lens. 
       FIG. 2  is a cross-sectional view of a structural example of the first liquid crystal cell  10 . Although the first liquid crystal cell  10  will be described here, the second liquid crystal cell  20  has the same cross-sectional structure as the first liquid crystal cell  10 , and the explanation thereof is omitted. 
     The first liquid crystal cell  10  includes an effective area A 11 , which modulates the transmitted polarization component, and a peripheral area A 12  outside the effective area A 11 . In the substrate SUB 1 , a plurality of first feed lines PL 1  and common line CL 1  are disposed in the peripheral area A 12  and covered with an insulating film IL. The first control electrodes E 1  are provided with the effective area A 11 , are located on the insulating film IL, and covered with the alignment film AL 1 . The first control electrodes E 1 , feed lines PL 1 , and common line CL 1  are electrically connected to the voltage controller DCT 1  in  FIG. 1 . 
     In the second substrate SUB 2 , the light-shielding layer BM is provided with the peripheral area A 12 . The inner area surrounded by the light-shielding layer BM corresponds to the effective area A 11 . The first common electrode C 1  is a single flat electrode located on substantially the entire surface of the effective area A 11 , and a part thereof extends to the peripheral area A 12 . The first common electrode C 1  is opposed to the plurality of the first control electrodes E 1  via the first liquid crystal layer LC 1  in the effective area A 11 . The first common electrode C 1  is opposed to the feed lines PL 1  and common line CL 1  in the peripheral area A 12 . 
     The first substrate SUB 1  and the second substrate SUB 2  are adhered by a sealant SE in the peripheral area A 12 . The sealant SE includes a conductive material CD. The conductive material CD is interposed between the common line CL 1  and the first common electrode C 1 . The common line CL 1  and the first common electrode C 1  are electrically connected each other. 
       FIG. 3  is a diagram illustrating a liquid crystal lens LL 1  formed in the first liquid crystal cell  10 . In  FIG. 3 , only the structures necessary for explanation will be illustrated. Although the explanation is omitted, a similar liquid crystal lens LL 2  can be formed in the second liquid crystal cell  20  as the liquid crystal lens LL 1  explained with reference to  FIG. 3 . 
     (A) of  FIG. 3  illustrates an off state (OFF) in which no potential difference occurs between the first control electrodes E 11  to E 15  and the first common electrode C 1 . The liquid crystal molecules LM 1  contained in the first liquid crystal layer LC 1  are initially aligned by the alignment restriction force of the alignment films AL 1  and AL 2 . 
     (B) of  FIG. 3  illustrates an on state (ON) where a potential difference is formed between the first control electrodes E 11  to E 15  and the first common electrode C 1 . The voltage controller DCT 1  supplies a predetermined voltage to the first control electrodes E 11  to E 15  and the first common electrode C 1 , respectively. The first liquid crystal layer LC 1  has a positive dielectric constant anisotropy, as described above. Thus, the liquid crystal molecule LM 1  is aligned such that the long axis thereof is along the electric field when the electric field is formed. 
     An electric field along the third direction Z is formed in the area where each of the first control electrodes E 11  and E 15  and the first common electrode CE 1  are opposed to each other, and thus, the liquid crystal molecule LM 1  is aligned such that the long axis thereof is along the third direction Z. The electric field is hardly formed in the area where the first control electrode E 13  and the first common electrode C 1  are opposed to each other, and the liquid crystal molecules LM 1  are maintained in the initial alignment state. In the area where the first control electrode E 12  and the first common electrode C 1  are opposed to each other, a middle alignment state between the area where the first control electrode E 11  and the first common electrode C 1  are opposed to each other and the area where the first control electrode E 13  and the first common electrode C 1  are opposed to each other, is formed. In the area where the first control electrode E 14  and the first common electrode C 1  are opposed to each other, a middle alignment state between the area where the first control electrode E 15  and the first common electrode C 1  and the area where the first control electrode E 13  and the first common electrode C 1  are opposed to each other, is formed. 
     The liquid crystal molecule LM 1  has a refractive index anisotropy Δn. Therefore, the first liquid crystal layer LC 1  has a refractive index distribution according to the alignment state of the liquid crystal molecule LM 1 . Or, the first liquid crystal layer LC 1  has a distribution of retardation expressed by Δn·d, where a thickness of the first liquid crystal layer LC 1  along the third direction Z is d. The liquid crystal lens LL 1  illustrated by the dotted line in the figure is formed by such a distribution of refractive index or retardation. 
     In the off state in (A) of  FIG. 3 , the first liquid crystal layer LC 1  has an almost uniform refractive index distribution and no liquid crystal lens is formed. Thus, the first polarization component POL 1  transmits through the first liquid crystal layer LC 1  without being modulated. 
     In the on state shown in (B) of  FIG. 3 , the first liquid crystal layer LC 1 , as described above, has a liquid crystal lens LL 1 . Therefore, the first polarization component POL 1  is modulated when transmitting through the first liquid crystal layer LC 1 . 
       FIG. 4  is a plan view illustrating a structural example of the first liquid crystal cell  10 . Note that, in  FIG. 4 , only the main parts of the first liquid crystal cell  10  will be illustrated. 
     The feed lines PL 1  are aligned in the first direction X in the peripheral area A 12 . Each of the feed lines PL 1  extends to a terminal part A 13 . Although this is not detailed, the terminal part A 13  includes a plurality of terminals connected to each of the feed lines PL 1 , and is electrically connected to a flexible wiring substrate and the like. 
     The first control electrodes E 1  have substantially the same shape, and are aligned in the second direction Y in the effective area A 11 . Each of the first control electrodes E 1  extends into the peripheral area A 12  and is electrically connected to any of the feed lines PL 1 . 
     The shape of the first control electrode E 1  will be described below. For example, when the first direction X parallel to the direction of extension of one side of the first liquid crystal cell  10  is used as a reference, the first control electrode E 1  has a plurality of segments that intersect at different angles with respect to the first direction X. Note that the angle θ of each segment with respect to the first direction X is defined as a counterclockwise angle with respect to the first direction X in the X-Y plane. 
     In the example of  FIG. 4  shown in an enlarged manner, the first control electrode E 1  includes, in the effective area A 11 , a plurality of first segments SG 1 , a plurality of second segments SG 2 , and a plurality of third segments SG 3 . Each of the first segments SG 1  extends in the direction intersecting the first direction X at a first angle θ 1 . Each of the second segments SG 2  extends in a direction intersecting the first direction X at a second angle θ 2 . Each of the third segments SG 3  extends in a direction intersecting the first direction X at a third angle θ 3 . The first angle θ 1 , second angle θ 2 , and third angle θ 3  are different angles from each other. In one example, the first angle θ 1  is 60°, the second angle θ 2  is 0°, and the third angle θ 3  is 120°. In another example, the first angle θ 1  is 30°, the second angle θ 2  is 0°, and the third angle θ 3  is 150°. 
     The first angle θ 1 , second angle θ 2 , and third angle θ 3  include at least one acute angle and at least one obtuse angle. In the example above, the first angle θ 1  is an acute angle, and the third angle  93  is an obtuse angle. 
     The obtuse angle is an integer multiple of the acute angle. In one of the above examples, the third angle θ 3  (120°) corresponds to twice the first angle θ 1  (60°). In the other example above, the third angle θ 3  (150°) corresponds to five times the first angle θ 1  (30°). 
     In effective area A 11 , the sum of the lengths L 1  of the first segments SG 1 , the sum of the lengths L 2  of the second segments SG 2 , and the sum of the lengths L 3  of the third segments SG 3  should be approximately equal. For example, if the lengths L 1  and L 3  are equal, the number of the first segments SG 1 , the number of the second segments SG 2 , and the number of the third segments SG 3  of the first control electrode E 1  are equal. 
       FIG. 5  illustrates the modulation effect of light in each segment of the first control electrode E 1 . (A) of  FIG. 5  shows the modulation effect of a segment group GP 1  which includes a plurality of first segments SG 1 . The first segments SG 1  are arranged at an almost equal pitch. (B) of  FIG. 5  shows the modulation effect of a segment group GP 2  which includes a plurality of second segments SG 2 . The second segments SG 2  are arranged at an almost equal pitch. (C) of  FIG. 5  shows the modulation effect of a segment group GP 3  which includes a plurality of third segments SG 3 . The third segments SG 3  are arranged at an almost equal pitch. 
     In the first liquid crystal cell  10  of  FIG. 4 , when the liquid crystal molecules LM 1  of the first liquid crystal layer LC 1  are initially aligned in the first direction X, the first polarization component POL 1  diverges, when passing through each of the segment groups GP 1  to GP 3 , in a direction that is substantially orthogonal to the extension direction of each segment. 
     For example, as shown in (A) of  FIG. 5 , if the first segment SG 1  extends in the direction of the first angle θ 1  of 60° with respect to the first direction X, the first polarization component POL 1  passing through the segment group GP 1  diverges in the 150°-330° direction in the X-Y plane. 
     As shown in (B) of  FIG. 5 , if the second segment SG 2  extends in the direction of the second angle θ 2  of 0° with respect to the first direction X, the first polarization component POL 1  passing through the segment group GP 2  diverges in the 90°-270° direction in the X-Y plane. 
     As shown in (C) of  FIG. 5 , if the third segment SG 3  extends in the direction of the third angle θ 3  of 120° with respect to the first direction X, the first polarization component POL 1  passing through the segment group GP 3  diverges in the 30°-210° direction in the X-Y plane. 
     Therefore, as shown in (D) of  FIG. 5 , the first polarization component POL 1  diverges in six directions in the X-Y plane. 
       FIG. 6  shows a structural example of a light control device  200 . Note that, in  FIG. 6 , only the main parts necessary for explanation will be shown. The first liquid crystal cell  10  and the second liquid crystal cell  20  overlap each other in the third direction Z. 
     The structure of the first liquid crystal cell  10  is as described in  FIG. 4 . 
     The second liquid crystal cell  20  is structured substantially similar to the first liquid crystal cell  10 . The second liquid crystal cell  20  has an effective area A 21 , which modulates the transmitted polarization component, and a peripheral area A 22  outside the effective area A 21 . In the third direction Z, the effective area A 21  overlaps the effective area A 11 , and the peripheral area A 22  overlaps the peripheral area A 12 . 
     The feed lines PL 2  are aligned in the first direction X in peripheral area A 22 . Each of the feed lines PL 2  extends to the terminal part A 23  and is electrically connected to a flexible circuit board and the like. The second control electrodes E 2  have substantially the same shape and are aligned in the second direction Y in the effective area A 21 . Each of the second control electrodes E 2  extends to the peripheral area A 22  and is electrically connected to any of the feed lines PL 2 . The shape of the second control electrode E 2  is the same as that of the first control electrode E 1 , and the explanation is omitted. In one example, such a second control electrode E 2  overlaps the first control electrode E 1  in a plan view. 
     Note that, the second control electrode E 2  may be displaced in at least one direction of the first direction X and the second direction Y with respect to the first control electrode E 1  in a plan view, or may be displaced in θ-direction with respect to the first control electrode E 1  in a plan view. 
     The alignment processing direction AD 1  of the alignment film AL 1  and the alignment processing direction AD 2  of the alignment film AL 2  in the first liquid crystal cell  10  are substantially orthogonal to the alignment processing direction AD 3  of the alignment film AL 3  and the alignment processing direction AD 4  of the alignment film AL 4  in the second liquid crystal cell  20 . However, the alignment processing directions AD 1  to AD 4  are not limited to the examples shown in the figure. 
     The light incident on the light control device  200  includes the first polarization component POL 1  and the second polarization component POL 2 . One polarization component of the first polarization component POL 1  and the second polarization component POL 2  will be mainly modulated in multiple directions in the first liquid crystal cell  10 , as described with reference to  FIG. 5 , and similarly, the other polarization component is mainly modulated in multiple directions in the second liquid crystal cell  20 . 
     According to the light control device  200 , the first liquid crystal cell  10  for mainly modulating one polarization component of incident light and the second liquid crystal cell  20  for mainly modulating the other polarization component of incident light can be configured with the same specifications except for the alignment processing direction. Therefore, by overlapping the first liquid crystal cell  10  and the second liquid crystal cell  20 , the light control device  200  which modulates (converges or diverges) incident light can be provided. 
     Furthermore, the first control electrode E 1  of the first liquid crystal cell  10  is electrically connected to the feed line PL 1  in the peripheral area A 12 . Furthermore, the second control electrode E 2  of the second liquid crystal cell  20  is electrically connected to the feed line PL 2  in the peripheral area A 22 . Therefore, in the effective areas A 11  and A 12 , feed lines PL 1  and PL 2  are not provided, and there are no missing parts of the first control electrode E 1  and the second control electrode E 2 . Therefore, in the effective areas A 11  and A 12 , an ineffective area that does not contribute to the formation of the liquid crystal lens can be reduced. 
     In addition, each of the first control electrode E 1  and the second control electrode E 2  is structured with a plurality of linearly extended segments, and the polarization component can be modulated in a direction approximately orthogonal to the direction of extension of each segment. This allows the desired liquid crystal lens to be formed. In one example, if each of the first control electrode E 1  and the second control electrode E 2  have N segments intersecting at N types of angles, the angle of each segment with respect to the first direction X is preferably set to a pitch of (180°/N). This allows uniform light distribution in multiple directions. 
     Furthermore, since the total length of each segment is almost equal, the degree of modulation of polarization components by each segment group can be controlled equally. 
       FIG. 7  illustrates another structural example of the light control device  200 . The structural example of  FIG. 7  differs from the structural example of  FIG. 6  in that the second control electrode E 2  is arranged to intersect the first control electrode E 1 . 
     The feed lines PL 2  are aligned in the second direction Y in peripheral area A 22 . The second control electrodes E 2  have substantially the same shape, and are aligned in the first direction X in the effective area A 21 . Each of the second control electrodes E 2  extends to the peripheral area A 22  and is electrically connected to any of the feed lines PL 2 . 
     The shape of the second control electrode E 2  will be described below. The second control electrode E 2  has a plurality of segments that intersect at different angles to the first direction X. In the example of  FIG. 7  shown in an enlarged manner, the second control electrode E 2  includes a plurality of fourth segments SG 4 , a plurality of fifth segments SG 5 , and a plurality of sixth segments SG 6  in the effective area A 21 . Each of the fourth segments SG 4  extends in the direction intersecting the first direction X at a fourth angle θ 4 . Each of the fifth segments SG 5  extends in the direction intersecting the first direction X at a fifth angle θ 5 . Each of the sixth segments SG 6  extends in the direction intersecting the first direction X at a sixth angle θ 6 . The fourth angle θ 4 , fifth angle θ 5 , and sixth angle θ 6  are different angles from each other. In addition, the first angle θ 1 , second angle θ 2 , and third angle θ 3  of the first control electrode E 1  described in  FIG. 4  are different from the fourth angle θ 4 , fifth angle θ 5 , and sixth angle θ 6 . 
     In one example, the fourth angle θ 4  is 120°, the fifth angle θ 5  is 90°, and the sixth angle θ 6  is 60°. 
     Furthermore, focusing on a relationship between the first control electrode E 1  and the second control electrode E 2 , a difference between the first angle θ 1  and the fourth angle θ 4 , a difference between the second angle θ 2  and the fifth angle θ 5 , and a difference between the third angle θ 3  and the sixth angle θ 6  are almost the same. For example, the difference between the first angle θ 1  (30°) and the fourth angle θ 4  (120°), the difference between the second angle θ 2  (0°) and the fifth angle θ 5  (90°), and the difference between the 3rd angle θ 3  (150°) and the 6th angle θ 6  (60°) are all 90°. In the case of the above angle combinations, the first liquid crystal cell  10  and the second liquid crystal cell  20  can be configured with substantially the same specifications, and the light control device  200  can be provided by overlapping one cell with a 90° rotation relative to the other cell. 
     Such an example corresponds to a case where the first control electrode E 1  and the second control electrode E 2  together have six segments intersecting at six different angles, wherein the angle of each segment with respect to the first direction X is set at a pitch of (180°/6=30°). 
     The fourth angle θ 4 , fifth angle θ 5 , and sixth angle θ 6  include at least one acute angle and at least one obtuse angle. In the above example, the sixth angle θ 6  is an acute angle, and the fourth angle θ 4  is an obtuse angle. 
     The obtuse angle is an integer multiple of the acute angle. In the example above, the fourth angle θ 4  (120°) is twice the sixth angle θ 6  (60°). 
     In the effective area A 21 , the sum of the lengths L 4  of the fourth segments SG 4 , the sum of the lengths L 5  of the fifth segments SG 5 , and the sum of the lengths L 6  of the sixth segments SG 6  should be approximately equal. For example, if the lengths L 4  to L 6  are equal, the number of the fourth segments SG 4 , the number of the fifth segments SG 5 , and the number of the sixth segments SG 6  are equal. 
     The alignment processing direction AD 1  of the alignment film AL 1  and the alignment processing direction AD 2  of the alignment film AL 2  in the first liquid crystal cell  10  are substantially orthogonal to the alignment processing direction AD 3  of the alignment film AL 3  and the alignment processing direction AD 4  of the alignment film AL 4  in the second liquid crystal cell  20 . 
     The above structural example can achieve the same advantages achieved by the aforementioned structural example. 
       FIG. 8  illustrates another structural example of the light control device  200 . 
     In this example, the first liquid crystal cell  10  of the light control device  200  will be described. Note that the second liquid crystal cell  20  is structured with the same specifications as the first liquid crystal cell  10  shown in the figure. However, the alignment processing directions AD 1  and AD 2  in the first liquid crystal cell  10  are different from the alignment processing directions AD 3  and AD 4  in the second liquid crystal cell  20 , as in the structural example above. 
     The first liquid crystal cell  10  includes a first effective area A 111  and a second effective area A 112 . The first effective area A 111  and the second effective area A 112  are adjacent to each other in the first direction X, for example. A plurality of first control electrodes E 1  are disposed in the first effective area A 111  and are aligned in the second direction Y. A plurality of second control electrodes E 2  are disposed in the second effective area A 112  and are aligned in the first direction X. Each of the first control electrodes E 1  is apart from the second control electrode E 2 . In the example of  FIG. 8 , the boundary line B between the first effective area A 111  and the second effective area A 112  is non-linear along the second control electrode E 2 , as shown by the dotted line. 
     The first control electrode E 1  includes, as with the structural example described with reference to  FIG. 4 , first segments SG 1 , second segments SG 2 , and third segments SG 3 . The second control electrode E 2  includes, as with the structural example described with reference to  FIG. 7 , fourth segments SG 4 , fifth segments SG 5 , and fifth segments SG 6 . Each of the segments SG 1  through SG 6  extends in a different direction from each other. 
     A plurality of first feed lines PL 1  are aligned in the first direction X in a peripheral area A 12 . Each of the first control electrodes E 1  extends into the peripheral area A 12  and is electrically connected to any of the first feed lines PL 1 . A plurality of second feed lines PL 2  are aligned in the peripheral area A 12  in the second direction Y. Each of the second control electrodes E 2  extends into the peripheral area A 12  and is electrically connected to any of the second feed lines PL 2 . 
     As above, the first liquid crystal cell  10  includes the first control electrode E 1  with three segments SG 1  to SG 3 , and the second control electrode E 2  with three segments SG 4  to SG 6 . Therefore, the polarization components passing through the first and second liquid crystal cells  10  and  20  diverge in 12 directions in the X-Y plane. Thus, uniform light distribution in more directions can be achieved. 
       FIG. 9  is a cross-sectional view illustrating another structural example of the first liquid crystal cell  10  and the second liquid crystal cell  20  of the light control device  200 . 
     In the structural example in (A) of  FIG. 9 , the first liquid crystal cell  10  and the second liquid crystal cell  20  are configured with the same specifications, while the second control electrode E 2  overlaps the first control electrode E 1  in a displaced manner. 
     In the structural example shown in (B) of  FIG. 9 , the first common electrode C 1  of the first liquid crystal cell  10  is omitted, and the second common electrode C 2  of the second liquid crystal cell  20  is omitted. In this structural example, the liquid crystal lens is formed in a so-called transverse field type in which an electric field is formed between the adjacent first control electrodes E 1  in the first liquid crystal cell  10 , and in the same manner, the liquid crystal lens is formed by the electric field between the adjacent second control electrodes E 2  in the second liquid crystal cell  20 . 
     In the structural example shown in (C) of  FIG. 9 , the first common electrode C 1  of the first liquid crystal cell  10  is patterned to have the same shape as the first control electrode E 1 , and the second common electrode C 2  of the second liquid crystal cell  20  is patterned to have the same shape as the second control electrode E 2 . 
     The above structural example can achieve the same advantages achieved by the aforementioned structural example. 
       FIG. 10  is a plan view of another structural example of the second control electrode E 2 . In the structural example of  FIG. 7 , the fourth segment SG 4 , fifth segment SG 5 , and sixth segment SG 6  are arranged in this order, forming a repeating unit of the second control electrode E 2 , however, the shape of the second control electrode E 2  is not limited thereto. 
     In the structural example in (A) of  FIG. 10 , the fifth segment SG 5 , fifth segment SG 5 , fourth segment SG 4 , sixth segment SG 6 , fourth segment SG 4 , and sixth segment SG 6  are arranged in this order, forming a repeating unit of the second control electrode E 2 . 
     In the structural example in (B) of  FIG. 10 , the fifth segment SG 5 , fourth segment SG 4 , sixth segment SG 6 , fifth segment SG 5 , sixth segment SG 6 , and fourth segment SG 4  are arranged in this order, forming a repeating unit of the second control electrode E 2 . 
     In the structural example in (C) of  FIG. 10 , the sixth segment SG 6 , fourth segment SG 4 , fifth segment SG 5 , fifth segment SG 5 , fourth segment SG 4 , and sixth segment SG 6  are arranged in this order, forming a repeating unit of the second control electrode E 2 . 
     In the structural example in (D) of  FIG. 10 , the fourth segment SG 4 , fifth segment SG 5 , and sixth segment SG 6  are arranged in this order, forming a repeating unit of the second control electrode E 2 . However, the fourth segment SG 4  extends in a direction intersecting the first direction X at a fourth angle (θ 4 ±Δθ). The fifth segment SG 5  extends in a direction intersecting the first direction X at a fifth angle (θ 5 ±Δθ). The sixth segment SG 6  extends in a direction intersecting the first direction X at a sixth angle (θ 6 ±Δθ). In one example, Δθ is given by (90°/N) when the first and second control electrodes E 1  and E 2  have N segments intersecting at N types angles. 
     For example, in a first repetition unit, Δθ is set to 5°, in a second repetition unit, Δθ is set to 10°, and in a third repetition unit, Δθ is set to 15°, so as to achieve uniform light distribution in more directions in the X-Y plane. 
     In every structural example, the repeating units are formed such that the sum of the lengths of each segment becomes equal each other. The second control electrode E 2  may be composed of a combination of the above structural examples. The structural example of the second control electrode E 2  described here is also applicable to the first control electrode E 1 . 
       FIG. 11  illustrates another structural example of the light control device  200 . (A) and (B) of  FIG. 11  show a combination of a plurality of segments of the first control electrode E 1  in the first liquid crystal cell  10  and a plurality of segments of the second control electrode E 2  in the second liquid crystal cell  20 . The angle in  FIG. 11  shows the angle of intersection with respect to the first direction X. 
     In the structural example in (A) of  FIG. 11 , the first control electrode E 1  includes a segment extending at a direction of 15°, segment extending at a direction of 45°, and segment extending at a direction of 75°. The pitch of the direction of each segment in the first control electrode E 1  is 30°. The second control electrode E 2  includes a segment extending at a direction of 0°, segment extending at a direction of 30°, segment extending at a direction of 60°, and segment extending at a direction of 90°. The pitch of the direction of each segment in the second control electrode E 2  is also 30°. 
     In the structural example in (B) of  FIG. 11 , the first control electrode E 1  includes a segment extending at a direction of 30°, segment extending at a direction of 60°, and segment extending at a direction of 90°. The second control electrode E 2  includes a segment extending at a direction of 0°, segment extending at a direction of 30°, segment extending at a direction of 60°, and segment extending at a direction of 90°. 
     The above structural example can achieve the same advantages achieved by the aforementioned structural example. 
       FIG. 12  shows another structural example of the light control device  200 . In the structural example of  FIG. 12 , the light control device  200  includes a first liquid crystal cell  10  and a second liquid crystal cell  20 . In this example, the effective area A 11  and the first control electrode E 1  of the first liquid crystal cell  10 , and the effective area A 21  and the second control electrode E 2  of the second liquid crystal cell  20  are shown. 
     The effective area A 11  is substantially the same as the effective area A 21 . That is, effective areas A 11  and A 21  have the same outline, and the shape of the first control electrode E 1  matches that of the second control electrode E 2 . For example, effective areas A 11  and A 21  have the outline of a regular dodecagon. The first control electrode E 1  includes first segments SG 1 , second segments SG 2 , and third segments SG 3 . The second control electrode E 2  includes fourth segments SG 4  that matches the first segments SG 1 , fifth segments SG 5  that matches the second segments SG 2 , and sixth segments SG 6  that matches the third segments SG 3 . 
     One side of the outline of the effective area A 11  that is parallel to the second segment SG 2  is denoted as reference line BL 1 . The reference line BL 1  is parallel to the first direction X. One side of the outline of the effective area A 21  that is parallel to the fifth segment SG 5  is denoted as reference line BL 2 . The reference line BL 2  intersects the first direction X at an angle of 30°. That is, the effective area A 21  corresponds to an effective area A 11  rotated by 30° in the X-Y plane. The outline of the effective area A 21  includes a side OS 2  parallel to the first direction X. The side OS 2  is adjacent to the reference line BL 2 . 
     The first liquid crystal cell  10  and the second liquid crystal cell  20  are arranged such that one side OS 2  of the effective area A 21  overlaps the reference line BL 1  of the effective area A 11 . Note that the alignment processing directions AD 1  and AD 2  in the effective area A 11  are orthogonal to the first direction X, and the alignment processing directions AD 3  and AD 4  in the effective area A 21  are parallel to the first direction X. 
     The above structural example can achieve the same advantages achieved by the aforementioned structural example. In addition, effective areas A 11  and A 21  can be formed by patterning using the same photomask. Therefore, the manufacturing cost can be reduced compared to the case where separate photomasks are prepared for manufacturing the first liquid crystal cell  10  and the second liquid crystal cell  20 . 
       FIG. 13  shows another structural example of the light control device  200 . In the structural example of  FIG. 13 , the light control device  200  includes a first liquid crystal cell  10 , second liquid crystal cell  20 , third liquid crystal cell  30 , and fourth liquid crystal cell  40 . The third liquid crystal cell  30  and the fourth liquid crystal cell  40  are structured the same as the first liquid crystal cell  10  and the second liquid crystal cell  20  described above. In this example, an effective area A 11  of the first liquid crystal cell  10 , effective area A 21  of the second liquid crystal cell  20 , effective area A 31  of the third liquid crystal cell  30 , and effective area A 41  of the fourth liquid crystal cell  40  are shown. 
     The effective areas A 11 , A 21 , A 31 , and A 41  are substantially the same, and have the same outline. Furthermore, the shape of the first control electrode E 1  in the effective area A 11 , shape of the second control electrode E 2  in the effective area A 21 , shape of the third control electrode E 3  in effective area A 31 , and shape of the fourth control electrode E 4  in effective area A 41  are identical. 
     Here, a reference line BL 1  of the effective area A 11 , reference line BL 2  of the effective area A 21 , reference line BL 3  of the effective area A 31 , and reference line BL 4  of the effective area A 41  will be considered. The effective area A 21  corresponds to the effective area A 11  rotated by 90° in the X-Y plane. The effective area A 31  corresponds to the effective area A 11  rotated by 180° in the X-Y plane. The effective area A 41  corresponds to the effective area A 11  rotated by 270° in the X-Y plane. 
     Alignment processing directions AD 1  and AD 2  in the effective area A 11 , and alignment processing directions AD 3  and AD 4  in the effective area A 21  are parallel to the first direction X. Alignment processing directions AD 5  and AD 6  in the effective area A 31  and alignment direction AD 7  and AD 8  in the effective area A 41  are orthogonal to the first direction X. 
     In such a light control device  200 , one polarization component of first polarization component POL 1  and second polarization component POL 2  is mainly modulated by the first liquid crystal cell  10  and the second liquid crystal cell  20 , and the other polarization component is mainly modulated by the third liquid crystal cell  30  and the fourth liquid crystal cell  40 . 
     The above structural example can achieve the same advantages achieved by the aforementioned structural example. 
       FIG. 14  shows another structural example of the light control device  200 . In the structural example of  FIG. 14 , the light control device  200  includes a first liquid crystal cell  10 , second liquid crystal cell  20 , and third liquid crystal cell  30 . Here, the effective area A 11  of the first liquid crystal cell  10 , effective area A 21  of the second liquid crystal cell  20 , and effective area A 31  of the third liquid crystal cell  30  are shown. 
     The effective areas A 11 , A 21 , and A 31  are substantially the same and have the same outline. Furthermore, the shape of the first control electrode E 1  in the effective area A 11 , the shape of the second control electrode E 2  in the effective area A 21 , and the shape of the third control electrode in the effective area A 31  are identical. 
     Here, a reference line BL 1  of the effective area A 11 , reference line BL 2  of the effective area A 21 , and reference line BL 3  of the effective area A 31  will be considered. The effective area A 21  corresponds to the effective area A 11  rotated by 30° in the X-Y plane. The effective area A 31  corresponds to the effective area A 11  rotated by 60° in the X-Y plane. 
     Alignment processing directions AD 1  and AD 2  in the effective area A 11  are parallel to the first direction X. Alignment processing directions AD 3  and AD 4  in the effective area A 21  are orthogonal to the first direction X. Alignment processing directions AD 5  and AD 6  in the effective area A 31  intersect the first direction at 135°. 
     In such a light control device  200 , one polarization component of the first polarization component POL 1  and the second polarization component POL 2  is mainly modulated by the first liquid crystal cell  10 , the other polarization component is mainly modulated by the second liquid crystal cell  20 , and both polarization components are modulated by the third liquid crystal cell  30 . 
     The above structural example can achieve the same advantages achieved by the aforementioned structural example. 
     In the above structural examples, the effective area is described as a polygon, but it may be a circle. When multiple liquid crystal cells are stacked and aligned, the effective area can be polygonal or circular to facilitate alignment. 
     Furthermore, in each liquid crystal cell, a pair of alignment films sandwiching the liquid crystal layer are aligned in the same direction and in opposite directions, but they may be aligned so that they cross each other. The liquid crystal mode can be horizontal alignment mode, vertical alignment mode, twist alignment mode, or any other mode. 
     As explained above, the present embodiment can provide a light control device and an illumination device that can reduce the ineffective area. 
     The present invention is not limited to the embodiments described above but the constituent elements of the invention can be modified in various manners without departing from the spirit and scope of the invention. Various aspects of the invention can also be extracted from any appropriate combination of a plurality of constituent elements disclosed in the embodiments. Some constituent elements may be deleted in all of the constituent elements disclosed in the embodiments. The constituent elements described in different embodiments may be combined arbitrarily.