Lighting control unit

Abstract

A light control device comprising: a first liquid crystal cell comprising a first substrate provided with a plurality of first control electrodes, a second substrate, and a first liquid crystal layer aligned in a twisted manner between the first substrate and the second substrate, a second liquid crystal cell comprising a third substrate provided with a plurality of second control electrodes, a fourth substrate, and a second liquid crystal layer aligned in a twisted manner between the third substrate and the fourth substrate, wherein the second liquid crystal cell is stacked on the first liquid crystal cell, the first control electrode overlays the second control electrode, the first liquid crystal cell has the function of modulating a first polarization component of incident natural light and converting it into a second polarization component, and converting a third polarization component of incident natural light into a fourth polarization component with almost no modulation, and the second liquid crystal cell has the function of modulating the fourth polarization component penetrating the first liquid crystal cell with virtually no modulation of the second polarization component penetrating the first liquid crystal cell.

Description

Technical area

[0001] The embodiment of the present invention relates to a light control device. Background technology

[0002] In recent years, light control devices using liquid crystal cells have been proposed. Such light control devices are primarily used to converge or diverge light beams of a single polarization component. One example discloses a light control device in which two liquid crystal cells are stacked, and one polarization component is modulated in one liquid crystal cell and the other polarization component is modulated in the other liquid crystal cell.

[0003] Furthermore, Patent Document 2 describes adding a chiral material to a liquid crystal of a liquid crystal lens to subject liquid crystal molecules to twist alignment. Patent Document 3 describes a liquid crystal lens in which the liquid crystal layer is sandwiched between two transparent substrates and functions as a variable focus lens. A heating electrode for directly heating the liquid crystal layer is arranged together with a phase modulation electrode group that modulates the phase of the liquid crystal layer by connecting it to a driving power source to apply a modulation voltage to the surface on the liquid crystal layer side of the transparent substrate. Determined documentPatent document Patent document 1: US 2019 / 0033669 A1 Patent document 2: JP 2009 - 139 623 A Patent document 3: JP 2006 - 201 243 A Overview of the inventionProblem to be solved by the invention

[0004] The purpose of the present embodiment is to provide a light control device that can be manufactured inexpensively. Means of solving the task

[0005] The object is achieved by the appended claims. According to the present embodiment, a light control device is provided, comprising: a first liquid crystal cell provided with a first substrate provided with a plurality of first control electrodes, a second substrate, and a first liquid crystal layer aligned in a twisted manner between the first substrate and the second substrate; a second liquid crystal cell provided with a third substrate provided with a plurality of second control electrodes, a fourth substrate, and a second liquid crystal layer aligned in a twisted manner between the third substrate and the fourth substrate; the second liquid crystal cell is stacked on the first liquid crystal cell, the first control electrode is superimposed on the second control electrode; the first liquid crystal cell has the function ofto modulate a first polarization component of incident natural light and convert it into a second polarization component, and to convert a third polarization component of incident natural light into a fourth polarization component with almost no modulation, and the second liquid crystal cell has the function of modulating the fourth polarization component penetrating the first liquid crystal cell with almost no modulation of the second polarization component penetrating the first liquid crystal cell. Effects of the invention

[0006] According to the present embodiment, it is possible to provide a light control device that can be manufactured inexpensively. Brief explanation of the drawings Fig. 1 shows a view for a configuration example of a light control device 100 of the present embodiment. Fig. 2 shows a sectional view of a training example of a first liquid crystal cell 1. Fig. 3 shows an exploded oblique view of the main part of the light control device 100. Fig. 4 is a view illustrating a liquid crystal lens LL1 formed in the first liquid crystal cell 1. Fig. 5 is a view illustrating the action of the liquid crystal lenses LL1 and LL2 by the light control device 100. Fig. 6 is a view illustrating the action of the liquid crystal lenses LL1 and LL2 by the light control device 100. Fig. 7 shows a sectional view of another embodiment of the light control device 100. Fig. 8 shows a view for another configuration example of the light control device 100 according to the present embodiment. Fig. Fig. 9 is a view illustrating the liquid crystal lens LL1 used in the Fig. 8 shown first liquid crystal cell 1. Fig. 10 shows a view for another configuration example of the light control device 100 of the present embodiment. Fig. 11 shows a view for an example of another shape of a first control electrode E1. Fig. 12 shows a view for an example of another shape of the first control electrode E1. Fig. 13 shows a sectional view of another embodiment of the light control device 100. Embodiments of the invention

[0007] The present embodiment will be explained below with reference to the drawings. The disclosure is merely an example, and the subject matter readily apparent to those skilled in the art regarding appropriate modification while maintaining the gist of the invention is naturally included within the scope of the present invention. To further clarify the explanation, the drawings may also schematically show the width, thickness, shape, etc. of the individual parts in comparison with the actual shape. However, this is merely an example and does not limit the interpretation of the present invention.In the present description and the respective drawings, the components that perform the same or similar functions as with reference to the previously mentioned drawings are designated by the same reference numerals, and overlapping detailed explanations may be omitted according to the circumstances.

[0008] Fig. 1 shows a view of one embodiment of a lighting control device 100 of the present embodiment. In one example, the first direction X, the second direction Y, and the third direction Z are orthogonal to each other, but they may intersect at an angle other than 90 degrees. In the present embodiment, viewing the XY plane defined by the first direction X and the second direction Y is referred to as a plan view.

[0009] The light control device 100 is provided with a first liquid crystal cell 1, a second liquid crystal cell 2, and a controller CT. The first liquid crystal cell 1 and the second liquid crystal cell 2 have essentially the same components.

[0010] The first liquid crystal cell 1 is provided with a first substrate SUB1, a second substrate SUB2, and a first liquid crystal layer LC1. The first substrate SUB1 is provided with an insulating substrate 11, a plurality of first control electrodes E1 provided on the insulating substrate 11, and an alignment film AL1 covering the first control electrodes E1. The second substrate SUB2 is provided with an insulating substrate 12, a first common electrode C1 provided on the insulating substrate 12, and an alignment film AL2 covering the first common electrode C1. The first common electrode C1 faces the plurality of first control electrodes E1.

[0011] The second liquid crystal cell 2 is provided with a third substrate SUB3, a fourth substrate SUB4, and a second liquid crystal layer LC2. The third substrate SUB3 is provided with an insulating substrate 13, a plurality of second control electrodes E2 arranged on the insulating substrate 13, and an alignment film AL3 covering the second control electrodes E2. The second control electrodes E2 are formed so as to overlap the first control electrodes E1 in the third direction Z. The fourth substrate SUB4 is provided with an insulating substrate 14, a second common electrode C2 provided on the insulating substrate 14, and an alignment film AL4 covering the second common electrode C2. The second common electrode C2 faces the plurality of second control electrodes E2.

[0012] The insulating substrates 11 to 14 are transparent substrates, e.g., glass or resin substrates.

[0013] The first control electrode E1, the second control electrode E2, the first common electrode C1 and the second common electrode C2 are transparent electrodes made of transparent conductive materials such as indium tin oxide (ITO) and indium zinc oxide (IZO).

[0014] Alignment films AL1 to AL4 are horizontal alignment films that have an alignment regulating force substantially parallel to the XY plane. For example, the alignment processing direction AD1 of alignment film AL1 and the alignment processing direction AD3 of alignment film AL3 are each parallel to the first direction X. The alignment processing direction AD2 of alignment film AL2 and the alignment processing direction AD4 of alignment film AL4 are each parallel to the second direction YD h. In the first liquid crystal cell 1, the alignment processing direction AD1 is orthogonal to the alignment processing direction AD2, and in the second liquid crystal cell 2, the alignment processing direction AD3 is orthogonal to the alignment processing direction AD4. The alignment processing may be a rubbing treatment or light alignment.

[0015] The first liquid crystal layer LC1 includes liquid crystal molecules LM1, which are held by the alignment films AL1 and AL2 between the first substrate SUB1 and the second substrate SUB2 and aligned at a 90° angle. Likewise, the second liquid crystal layer LC2 includes liquid crystal molecules LM2, which are held by the alignment films AL3 and AL4 between the third substrate SUB3 and the fourth substrate SUB4 and aligned at a 90° angle. These first and second liquid crystal layers LC1 and LC2, for example, have a positive dielectric constant anisotropy.

[0016] The second liquid crystal cell 2 is stacked on the first liquid crystal cell 1 in the third direction Z. The insulating substrate 12 and the insulating substrate 13 are bonded together by a transparent adhesive layer 3. The refractive index of the adhesive layer 3 corresponds to the refractive index of the insulating substrates 12 and 13. In contrast, the outer surface 11A of the insulating substrate 11 and the outer surface 14A of the insulating substrate 14 are in contact with an air layer.

[0017] The controller CT is provided with voltage controllers DCT1 and DCT2. The voltage controller DCT1 controls the voltage to be applied to the first control electrode E1 and the first common electrode C1 in the first liquid crystal cell 1. The voltage controller DCT2 controls the voltage to be applied to the second control electrode E2 and the second common electrode C2 in the second liquid crystal cell 2.

[0018] Such a light control device 100 is combined, for example, with a light source that emits natural light and is installed such that the outer surface 11A serves as an incident surface for the natural light. The first liquid crystal cell 1 has the function of modulating a first polarization component of incident natural light and converting it into a second polarization component, and of converting a third polarization component of incident natural light into a fourth polarization component with almost no modulation. The second liquid crystal cell 2 has the function of modulating a fourth polarization component that penetrates the first liquid crystal cell 1 with almost no modulation of the second polarization component that penetrates the first liquid crystal cell 1. The functions of the first liquid crystal cell 1 and the second liquid crystal cell 2 will be described in detail later.

[0019] Modulation here means the focusing or divergence of the polarization component penetrating the liquid crystal layer by a refractive index distribution lens (hereinafter referred to as liquid crystal lens) formed on the liquid crystal layer. That is, the first liquid crystal cell 1 focuses or diverges the first polarization component, and the second liquid crystal cell 2 focuses or diverges the fourth polarization component. In the first liquid crystal cell 1, the third polarization component is hardly focused or diverged, and in the second liquid crystal cell 2, the second polarization component is also hardly focused or diverged. The degree of focusing 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 1 is controlled by the voltage controller DCT1 and the modulation rate of the fourth polarization component in the second liquid crystal cell 2 is controlled by the voltage controller DCT2.

[0020] As described above, the first liquid crystal cell 1 and the second liquid crystal cell 2 have substantially the same components and the same rotational force. In the present embodiment, the first liquid crystal cell 1 and the second liquid crystal cell 2 each have a rotational force to rotate the polarization plane of the incident polarization component (linearly polarized light) by 90°. That is, the polarization plane of the first polarization component is orthogonal to the polarization plane of the second polarization component, and the polarization plane of the third polarization component is orthogonal to the polarization plane of the fourth polarization component. When the first and third polarization components are orthogonal to each other, the first and fourth polarization components have the same polarization plane, and the second and third polarization components have the same polarization plane.

[0021] Fig. 2 shows a sectional view of a configuration example of the first liquid crystal cell 1. Although the first liquid crystal cell 1 is explained here, the second liquid crystal cell 2 also has the same cross-sectional structure as the first liquid crystal cell 1, and the explanation thereof is omitted.

[0022] With respect to the first substrate SUB1, a plurality of first control electrodes E1 are arranged in a first modulation region A11 in a first direction X, spaced apart from each other. A power supply line PL is provided in an edge region A12 outside the first modulation region A11. The plurality of first control electrodes E1 and the power supply line PL are electrically connected to the Fig. 1 shown voltage control DCT1.

[0023] In the second substrate SUB2, the first common electrode C1 is, for example, a single flat electrode positioned on substantially the entire surface of the first modulation region A11 and partially extending to the edge region A12. The first common electrode C1 faces the plurality of first control electrodes E1 in the first modulation region A11 via the first liquid crystal layer LC1. The first common electrode C1 faces the power supply line PL in the edge region A12.

[0024] The first substrate SUB1 and the second substrate SUB2 are bonded together by a gasket SE in the edge region A12. The gasket SE is coated with a conductive material CD. The conductive material CD is provided between the power supply line PL and the first common electrode C1 and electrically connects the power supply line PL to the first common electrode C1.

[0025] Fig. 3 shows an exploded oblique view of the main part of the light control device 100. The first common electrode C1 superimposed on the first modulation region A11 and the second common electrode C2 superimposed on the second modulation region A21 are shown by dashed lines. The plurality of first control electrodes E1 are lined up in the first direction X in the first modulation region A11 at specific pitches D1. Each of the first control electrodes E1 is, for example, a belt-shaped electrode extending in the second direction Y. Each of the first control electrodes E1 has the same width W1 along the first direction X. The plurality of second control electrodes E2 are lined up in the first direction X in the second modulation region A21 at specific pitches D2. Each of the second control electrodes E2 is, for example, a belt-shaped electrode extending in the second direction Y.Each of the second control electrodes E2 has the same width W2 along the first direction X. The width W1 corresponds to the width W2, and the distance D1 corresponds to the distance D2. That is, in plan view, the plurality of first control electrodes E1 each overlap the plurality of second control electrodes E2. The widths W1 and W2 and the distances D1 and D2 are, for example, 10 µm to 30 µm.

[0026] In the Fig. In the example shown in Figure 3, the first modulation region A11 and the second modulation region A21 are formed in a rectangle extending in the first direction X. However, they may also be formed in a rectangle extending in the second direction Y, or in a circular shape, an oval shape, or other shapes. The first modulation region A11 and the second modulation region A21 assume the same shape and overlap in plan view.

[0027] Fig. Fig. 4 is a view illustrating a liquid crystal lens LL1 formed in the first liquid crystal cell 1. In Fig. 4 only shows the configurations necessary for explanation. Although the explanation is omitted, a liquid crystal lens LL2 similar to the one shown in FIG. Fig. 4 explained liquid crystal lens LL1. (A) in Fig. Figure 4 shows an off state (OFF) in which no potential difference is generated between the first control electrodes E11 to E15 and the first common electrode C1. The liquid crystal molecules LM1 contained in the first liquid crystal layer LC1 are twistedly aligned by the alignment regulating force of the alignment films AL1 and AL2. (Am Fig. 4 shows an ON state in which a potential difference is formed between the first control electrodes E11 to E15 and the first common electrode C1. The voltage controller DCT1 supplies a predetermined voltage to the first control electrodes E11 to E15 and the first common electrode C1, respectively. As described above, the first liquid crystal layer LC1 has a positive dielectric constant anisotropy. Therefore, the liquid crystal molecules LM1 are aligned such that their long axes run along the electric field in the state in which an electric field is formed. In one example, the first control electrodes E11, E12, E13, E14, and E15 are supplied with voltages of 7V, 3V, 0V, 3V, and 7V, respectively, and the first common electrode C1 is supplied with a voltage of 0V.

[0028] In a region where each of the first control electrodes E11 and E15 and the first common electrode C1 are opposed, the electric field is formed along the third direction Z, so that the liquid crystal molecules LM1 are aligned such that their long axis runs along the third direction Z. In a region where the first control electrode E13 and the first common electrode C1 are opposed, almost no electric field is formed, and the liquid crystal molecules LM1 remain in the initial alignment state (twisted alignment state). In a region where the first control electrode E12 and the first common electrode C1 are opposed, an intermediate alignment state is formed between a region where the first control electrode E11 and the first common electrode C1 are opposed and a region where the first control electrode E13 is opposed to the first common electrode C1.In a region where the first control electrode E14 and the first common electrode C1 are opposed, an intermediate alignment state is formed between a region where the first control electrode E15 and the first common electrode C1 are opposed and a region where the first control electrode E13 and the first common electrode C1 are opposed.

[0029] The liquid crystal molecule LM1 has a refractive index anisotropy Δn. Therefore, the first liquid crystal layer LC1 has a refractive index distribution corresponding to the alignment state of the liquid crystal molecules LM1. Alternatively, the first liquid crystal layer LC1 has a retardation distribution or a phase distribution expressed by Δn d, where the thickness of the first liquid crystal layer LC1 along the third direction Z is d. In one example, the thickness d is 10 μm to 50 μm. The liquid crystal lens LL1, shown by the dashed line in the drawing, is formed by such a refractive index distribution, retardation distribution, or phase distribution. The liquid crystal lens LL1 shown in the drawing functions as a convex lens.

[0030] Next, the action of the liquid crystal lenses LL1 and LL2 by the light control device 100 is described with reference to the Fig. 5 and Fig. 6. In the following explanation, when the traveling direction of light is along the third direction Z, linearly polarized light with a polarization plane along the first direction X is referred to as first polarized light (P-polarized light) POL1, and linearly polarized light with a polarization plane along the second direction Y is referred to as second polarized light (S-polarized light) POL2. The light source LS emits natural light with the first polarized light POL1 and the second polarized light POL2. The first liquid crystal cell 1 is positioned between the light source LS and the second liquid crystal cell 2.

[0031] As in Fig. As shown in Figure 5, the first polarized light (first polarization component) POL1 of the natural light is focused by the liquid crystal lens LL1 in the first liquid crystal cell 1 and converted into the second polarized light (second polarization component) POL2 by rotating its polarization plane by 90 degrees. The second polarized light POL2, which passes through the first liquid crystal cell 1, passes through the second liquid crystal cell 2 without being focused by the liquid crystal lens LL2 and is converted into the first polarized light POL1 by rotating its polarization plane by 90 degrees. That is, the first polarized light POL1 of the natural light emitted from the light source LS is focused by the light control device 100.

[0032] As in Fig. As shown in Figure 6, the second polarized light (third polarization component) POL2 of the natural light passes through the first liquid crystal cell 1 without being focused by the liquid crystal lens LL1, and is converted into the first polarized light (fourth polarization component) POL1 by rotating its polarization plane by 90 degrees. The first polarized light POL1 passing through the first liquid crystal cell 1 is focused by the liquid crystal lens LL2 in the second liquid crystal cell 2 and converted into the second polarized light POL2 by rotating its polarization plane by 90 degrees. That is, the second polarized light POL2 of the natural light emitted from the light source LS is focused by the light control device 100.

[0033] According to such a light control device 100, the first liquid crystal cell 1 for modulating the first polarized light POL1 of natural light and the second liquid crystal cell 2 for modulating the second polarized light POL2 of natural light can be formed with the same specifications. Therefore, regardless of the shape of the modulation region, by stacking the first liquid crystal cell 1 and the second liquid crystal cell 2, a light control device 100 that modulates (focuses or diverges) natural light can be provided. Compared with the case where the first liquid crystal cell 1 and the second liquid crystal cell 2 are formed with different specifications, the manufacturing line according to the present embodiment can be unified, and the light control device 100 can be manufactured inexpensively.

[0034] Fig. 7 shows a sectional view of another embodiment of the light control device 100. The Fig. The training example shown in Figure 7 differs from that shown in Fig. 1 is that the first substrate SUB1 and the third substrate SUB3 are bonded to each other by a transparent adhesive layer 3. Furthermore, the second substrate SUB2 and the fourth substrate SUB4 are in contact with an air layer. Specifically, the adhesive layer 3 bonds the insulating substrate 11 and the insulating substrate 13. The refractive index of the adhesive layer 3 is the same as that of the insulating substrates 11 and 13. In contrast, the outer surface 12A of the insulating substrate 12 and the outer surface 14A of the insulating substrate 14 are each in contact with the air layer.

[0035] The first common electrode C1 is provided on the inner surface 12B of the insulating substrate 12, and the second common electrode C2 is provided on the inner surface 14B of the insulating substrate 14. That is, in the light control device 100, the first liquid crystal layer LC1 and the second liquid crystal layer LC2 are positioned between the first common electrode C1 and the second common electrode C2, which are flat electrodes. For example, the first common electrode C1 and the second common electrode C2, which are made of ITO, are conductive layers and serve as UV-absorbing layers.

[0036] With such a configuration example, the same effect as the above configuration example can be achieved. Furthermore, the ultraviolet rays incident from the outer surface 12A are absorbed by the first common electrode C1, and the ultraviolet rays incident from the outer surface 14A are absorbed by the second common electrode C2. Consequently, deterioration of the first liquid crystal layer LC1 and the second liquid crystal layer LC2 due to ultraviolet rays is suppressed.

[0037] Furthermore, the charge on the second substrate SUB2 is discharged via the first common electrode C1, and the charge on the fourth substrate SUB4 is discharged via the second common electrode C2. Consequently, the alignment failure of the liquid crystal molecules caused by unwanted charging is suppressed in the first liquid crystal layer LC1 and the second liquid crystal layer LC2.

[0038] Fig. Fig. 8 shows a view of another embodiment of the light control device 100 according to the present embodiment. Fig. The training example shown in Figure 8 differs from that shown in Fig. 1 is that, in the first liquid crystal cell 1, the first substrate SUB1 is provided with the first control electrodes E1 and the first common electrodes C1, and the first common electrodes C1 are positioned between the adjacent first control electrodes E1. Furthermore, the first control electrodes E1 and the first common electrodes C1 are positioned on the same layer. For example, the first control electrodes E1 and the first common electrodes C1 are provided on the insulating substrate 11 and covered with the alignment film AL1. These first control electrodes E1 and the first common electrodes C1 are made of, for example, the same transparent conductive material.In the example shown in the drawing, a single first control electrode E1 is arranged between the adjacent first common electrodes C1, but it is also possible that a plurality of first control electrodes E1 can be arranged between the adjacent first common electrodes C1, or a plurality of first common electrodes C1 can be arranged between the adjacent first control electrodes E1.

[0039] In the second liquid crystal cell 2, as in the first liquid crystal cell 1, the third substrate SUB 3 is also provided with second control electrodes E2 and second common electrodes C2. The second common electrodes C2 are positioned between the adjacent second control electrodes E2. Furthermore, the second control electrodes E2 and the second common electrodes C2 are positioned on the same layer.

[0040] The width of the first common electrode C1 corresponds to the width W2 of the second common electrode C2, and the distance between the first control electrode E1 and the first common electrode C1 corresponds to the distance between the second control electrode E2 and the second common electrode C2. The second control electrode E2 is positioned directly above the first control electrode E1, and the second common electrode C2 is positioned directly above the first common electrode C1. That is, in plan view, the plurality of first control electrodes E1 respectively overlap the plurality of second control electrodes E2, and the plurality of first common electrodes C1 respectively overlap the plurality of second common electrodes C2.

[0041] The first liquid crystal cell 1 and the second liquid crystal cell 2 are bonded together by a transparent adhesive layer 3. In the illustrated example, the second substrate SUB2 and the third substrate SUB3 are bonded together by the adhesive layer 3. The refractive index of the adhesive layer 3 corresponds to the refractive index of the insulating substrates 12 and 13. In contrast, the respective outer surfaces of the insulating substrate 11 and the insulating substrate 14 are in contact with the air layer. No electrodes are provided on the second substrate SUB2 and the fourth substrate SUB4. In particular, from the viewpoint of suppressing the incidence of ultraviolet rays from the fourth substrate SUB4, the outer surface of the fourth substrate SUB4 (or the outer surface of the insulating substrate 14) may also be provided with a UV-absorbing layer. Specific examples of the UV-absorbing layer will be described below with reference to Fig. 13 explained.

[0042] Fig. Fig. 9 is a view illustrating the liquid crystal lens LL1 used in the Fig. 8 shown first liquid crystal cell 1. In Fig. 9 only the configurations necessary for explanation are shown. Although the explanation is omitted, the liquid crystal lens LL2 can also be used in the second liquid crystal cell 2 similar to the one shown in FIG. Fig. 9 explained liquid crystal lens LL1. (A) in Fig. Figure 9 shows an off state (OFF) in which no potential difference is generated between the first control electrodes E1 and the first common electrodes C1. The liquid crystal molecules LM1 contained in the first liquid crystal layer LC1 are twistedly aligned by the alignment regulating force of the alignment films AL1 and AL2. (Am Fig. Figure 9 shows an ON state in which a potential difference is formed between the first control electrodes E1 and the first common electrodes C1. The voltage controller DCT1 supplies a predetermined voltage to the first control electrodes E1 and the first common electrodes C1, respectively. The liquid crystal molecules LM1 are aligned such that their longitudinal axis runs along the electric field in the state in which an electric field is formed. This forms the liquid crystal lens LL1, which is indicated by a dashed line in the drawing.

[0043] Also in the Fig. 8 and Fig. 9, the same effect as in the above example can be achieved. In addition, in such an example, the power supply line PL and the conductive material CD, which are Fig. 2, is not required, and the training can be simplified. Fig. 8 and Fig. 9 shown training example, as in the one in Fig. 7, the first substrate SUB1 and the third substrate SUB3 are bonded by a transparent adhesive layer 3.

[0044] Fig. Fig. 10 shows a view of another embodiment of the light control device 100 of the present embodiment. Compared to the Fig. The training example shown in Figure 8 differs in Fig. The embodiment shown in FIG. 10 is different in that the first substrate SUB1 is provided with an insulating film (first insulating film) IL1 positioned between the first control electrodes E1 and the first common electrodes C1. That is, the difference lies in the fact that the first control electrodes E1 are positioned on a different layer than the first common electrodes C1. For example, the first common electrodes C1 are positioned on the insulating substrate 11 and covered by the insulating film IL1. The first control electrodes E1 are positioned on the insulating film IL1 and covered by the alignment film AL1. The first common electrodes C1 are positioned between the adjacent first control electrodes E1.

[0045] In the second liquid crystal cell 2, as in the first liquid crystal cell 1, the third substrate SUB3 is provided with the insulating film (second insulating film) IL2 positioned between the second control electrodes E2 and the second common electrodes C2. For example, the second common electrodes C2 are provided on the insulating substrate 13 and covered by the insulating film IL2. The second control electrodes E2 are provided on the insulating film IL2 and covered by the alignment film AL3. The second common electrodes C2 are positioned between the adjacent second control electrodes E2.

[0046] The width of the first common electrode C1 corresponds to the width W2 of the second common electrode C2, and the distance between the first control electrode E1 and the first common electrode C1 corresponds to the distance between the second control electrode E2 and the second common electrode C2. The second control electrode E2 is positioned directly above the first control electrode E1, and the second common electrode C2 is positioned directly above the first common electrode C1. That is, in plan view, the plurality of first control electrodes E1 respectively overlap the plurality of second control electrodes E2, and the plurality of first common electrodes C1 respectively overlap the plurality of second common electrodes C2.

[0047] The second substrate SUB2 and the third substrate SUB3 are bonded to each other by a transparent adhesive layer 3. The refractive index of the adhesive layer 3 corresponds to the refractive index of the insulating substrates 12 and 13. In contrast, the respective outer surfaces of the insulating substrate 11 and the insulating substrate 14 are in contact with the air layer. No electrodes are provided on the second substrate SUB2 and the fourth substrate SUB4. In particular, from the viewpoint of suppressing the incidence of ultraviolet rays from the fourth substrate SUB4, the outer surface of the fourth substrate SUB4 (or the outer surface of the insulating substrate 14) may also be provided with a UV-absorbing layer. Specific examples of the UV-absorbing layer will be described below with reference to Fig. 13 explained.

[0048] In the Fig. The training example shown in Figure 10 can produce the same effect as in the example shown in Fig. 8. In addition, the first control electrodes E1 and the first common electrodes C1, which are supplied with different voltages, are provided over the insulating film IL1, so that the distance between the electrodes arranged on the same layer is increased and the yield can be improved. In the embodiment shown in Fig. 10 shown training example, as in the one in Fig. 7, the first substrate SUB1 and the third substrate SUB3 are bonded by the transparent adhesive layer 3.

[0049] The first control electrodes E1 and the second control electrodes E2, which are described with reference to Fig. 8 and Fig. 10, and the first common electrodes C1 and the second common electrodes C2 may be the ones shown in Fig. They can be the ribbon-shaped electrodes explained in Section 3, or they can take other shapes. Examples of the other shapes are explained below.

[0050] In the Fig. In the example shown in Figure 11, the first control electrode E1 is formed in a substantially circular dot shape. The first common electrode C1 is formed in a ring shape that surrounds each of the plurality of first control electrodes E1. The plurality of first control electrodes E1 and the first common electrode C1 are each electrically connected to the voltage controller DCT1. For example, an electric field is formed between each of the first control electrodes E1 and the first common electrode C1, thereby forming a lens array.

[0051] In Fig. In the example shown in Figure 12, the plurality of first control electrodes E1 are formed in concentric circles. The plurality of first control electrodes E1 are each electrically connected to the voltage controller DCT1. For example, the voltage supplied to each of the first control electrodes E1 is controlled, thereby forming a circular lens.

[0052] Fig. 13 shows a sectional view of another embodiment of the light control device 100. The Fig. The training example shown in Figure 13 differs from the training examples shown in Fig. 8 and Fig. 10 is that the first substrate SUB1 and the third substrate SUB3 are bonded to each other by a transparent adhesive layer 3. Furthermore, the second substrate SUB2 and the fourth substrate SUB4 are positioned on the side facing away from the adhesive layer 3. Furthermore, a first UV-absorbing layer 21 is provided on the outer surface of the first liquid crystal cell 1 (or the outer surface of the second substrate SUB2), and a second UV-absorbing layer 22 is provided on the outer surface of the second liquid crystal cell 2 (or the outer surface of the fourth substrate SUB4). Specifically, the first UV-absorbing layer 21 is positioned on the outer surface 12A of the insulating substrate 12, and the second UV-absorbing layer 22 is positioned on the outer surface 14A of the insulating substrate 14. That is,In the light control device 100, the first liquid crystal layer LC1 and the second liquid crystal layer LC2 are positioned between the first UV-absorbing layer 21 and the second UV-absorbing layer 22. The first UV-absorbing layer 21 and the second UV-absorbing layer 22 are transparent, conductive layers made of, for example, ITO.

[0053] With this training example, the same effect can be achieved as with the one in Fig. 7. That is, the ultraviolet rays incident from the side of the second substrate SUB2 where no electrode is present are absorbed by the first UV-absorbing layer 21. The ultraviolet rays incident from the side of the fourth substrate SUB4 where no electrode is present are absorbed by the second UV-absorbing layer 22. Consequently, the deterioration of the first liquid crystal layer LC1 and the second liquid crystal layer LC2 by ultraviolet rays is suppressed.

[0054] In the Fig.In the embodiment shown in Figure 13, the first control electrodes E1 and the first common electrodes C1 of the first substrate SUB1 are on the same layer, but the first control electrodes E1 may be positioned on a different layer than the first common electrodes C1. Likewise, the second control electrodes E2 and the second common electrodes C2 of the third substrate SUB3 may be positioned on the same layer, or the second control electrodes E2 may be positioned on a different layer than the second common electrodes C2.

[0055] As explained above, according to the present embodiment, a light control device can be provided which can be manufactured inexpensively.

[0056] This invention is not limited to the above-mentioned embodiments, but can be made more concrete by modifying the components to the extent that the implementation does not deviate from the gist of the invention. Various inventions can also be formed by appropriately combining the multiple components disclosed in the above-mentioned embodiments. For example, some of the components may be deleted from all the components shown in the embodiments. Furthermore, components from different embodiments can be combined as needed. Explanation of reference symbols 100 lighting control unit 1 first liquid crystal cell 2 second liquid crystal cell 3 adhesive layer SUB1 first substrate E1 first control electrode SUB2 second substrate LC1 first liquid crystal layer SUB3 third substrate E2 second control electrode SUB4 fourth substrate LC2 second liquid crystal layer C1 first common electrode C2 second common electrode A11 first modulation range A21 second modulation range IL1, IL2 insulating film LL1, LL2 liquid crystal lens 21 first UV-absorbing layer 22 second UV-absorbing layer

Claims

[1] A light control device comprising: a first liquid crystal cell comprising a first substrate provided with a plurality of first control electrodes, a second substrate, and a first liquid crystal layer aligned in a twisted manner between the first substrate and the second substrate, a second liquid crystal cell comprising a third substrate provided with a plurality of second control electrodes, a fourth substrate, and a second liquid crystal layer aligned in a twisted manner between the third substrate and the fourth substrate, wherein the second liquid crystal cell is stacked on the first liquid crystal cell, the first control electrode overlays the second control electrode, the first liquid crystal cell has the function of modulating a first polarization component of incident natural light and converting it into a second polarization component, and converting a third polarization component of incident natural light into a fourth polarization component with almost no modulation, and the second liquid crystal cell has the function of modulating the fourth polarization component penetrating the first liquid crystal cell with virtually no modulation of the second polarization component penetrating the first liquid crystal cell. [2] Light control device according to claim 1, wherein the first liquid crystal cell and the second liquid crystal cell have the same rotational force, the second polarization component and the third polarization component have the same polarization plane, and the first polarization component and the fourth polarization component have the same polarization plane. [3] Light control device according to claim 1, wherein the plurality of first control electrodes are arranged in a first direction each with a first regular pitch, the plurality of second control electrodes are each arranged in the first direction at a second regular pitch, and the plurality of first and a plurality of second control electrodes extend in a second direction that intersects the first direction. [4] Light control device according to claim 3, wherein a width of each of the first control electrodes corresponds to a width of each of the second control electrodes, and the first regular pitch is equal to the second regular pitch. [5] A light control device according to claim 4, wherein the first liquid crystal cell has a first modulation region in which the plurality of first control electrodes are provided, the second liquid crystal cell has a second modulation region in which the plurality of second control electrodes are provided, wherein the first modulation region and the second modulation region take the same shape and are formed in a rectangle. [6] The light control device according to claim 5, wherein the second substrate is provided with a first common electrode opposite to the plurality of first control electrodes, and the fourth substrate is provided with a second common electrode opposite to the plurality of second control electrodes. [7] The light control device according to claim 6, further provided with a transparent adhesive layer for bonding the first substrate and the third substrate. [8] The light control device according to claim 7, wherein the second substrate and the fourth substrate are in contact with an air layer. [9] The light control device according to claim 6, further comprising a transparent adhesive layer for bonding the second substrate and the third substrate. [10] The light control device according to claim 9, wherein the first substrate and the fourth substrate are in contact with an air layer. [11] A light control device according to claim 1, wherein the first substrate is further provided with a first common electrode positioned between the adjacent first control electrodes, wherein the first control electrode and the first common electrode are positioned on the same layer, the second substrate is further provided with a second common electrode positioned between the adjacent second control electrodes, wherein the second control electrode and the second common electrode are positioned on the same layer, and the first common electrode overlays the second common electrode. [12] A light control device according to claim 11, further comprising: a transparent adhesive layer for bonding the first liquid crystal cell and the second liquid crystal cell, and a UV-absorbing layer provided on at least one of the outer surface of the first liquid crystal cell and the outer surface of the second liquid crystal cell, wherein the UV-absorbing layer is a transparent conductive layer. [13] The light control device according to claim 11, further comprising: a transparent adhesive layer for bonding the first substrate and the third substrate, a first UV-absorbing layer provided on the outer surface of the second substrate, a second UV-absorbing layer provided on the outer surface of the fourth substrate, wherein the first UV-absorbing layer and the second UV-absorbing layer are transparent conductive layers. [14] The light control device according to claim 1, wherein the first substrate is further provided with a first common electrode positioned between the adjacent first control electrodes and a first insulating film positioned between the first control electrode and the first common electrode, and the second substrate is further provided with a second common electrode positioned between the adjacent second control electrodes and a second insulating film positioned between the second control electrode and the second common electrode, wherein the first common electrode overlies the second common electrode. [15] A light control device according to claim 14, further comprising: a transparent adhesive layer for bonding the first liquid crystal cell and the second liquid crystal cell, and a UV-absorbing layer provided on at least one of the outer surface of the first liquid crystal cell and the outer surface of the second liquid crystal cell, wherein the UV-absorbing layer is a transparent conductive layer. [16] The light control device according to claim 14, further comprising: a transparent adhesive layer for bonding the first substrate and the third substrate, a first UV-absorbing layer provided on the outer surface of the second substrate, a second UV-absorbing layer provided on the outer surface of the fourth substrate, wherein the first UV-absorbing layer and the second UV-absorbing layer are transparent conductive layers. [17] The light control device according to claim 1, wherein the first substrate is further provided with a first common electrode surrounding the plurality of first control electrodes, respectively. [18] The light control device according to claim 1, wherein the plurality of first control electrodes are formed in concentric circles.

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