Light control sheet
The light-controlling sheet addresses peeling and adhesion issues at sharp corners by using arc-shaped chamfered corners and a sealant, enhancing mechanical strength and reliability.
Patent Information
- Application Number
- PCT/JP2025/018188
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-05-24
- Filing Date
- 2025-05-20
- Publication Date
- 2025-11-27
AI Technical Summary
The concentration of stress at sharp corners in light-controlling sheets leads to peeling and adhesion issues between layers, particularly when the corners are steep, making them prone to damage and interference.
The light-controlling sheet design incorporates arc-shaped chamfered corners with a radius of curvature of 3 mm or more, connecting the intersecting surfaces with a third surface to maintain adhesion and prevent peeling, while using a sealant to cover exposed electrode surfaces.
This design enhances the mechanical strength and resistance to external forces, reducing the likelihood of peeling and interference at corners, ensuring reliable operation and aesthetic integrity.
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Figure JP2025018188_27112025_PF_FP_ABST
Abstract
Description
Light-adjusting sheet
[0001] The present disclosure relates to a light-control sheet.
[0002] The light-controlling sheet includes a pair of electrode sheets and a light-controlling layer located between the pair of electrode sheets. Each electrode sheet includes an insulating transparent substrate and a conductive transparent electrode layer. The light-controlling layer is located between the pair of transparent electrode layers.
[0003] The light-controlling layer, for example, contains a liquid crystal composition having liquid crystal molecules. The liquid crystal molecules exhibit different alignment states between a state where no potential difference is applied between a pair of transparent electrode layers and a state where a potential difference is applied between the pair of transparent electrode layers. The light-controlling sheet changes its light transmittance depending on the alignment state of the liquid crystal molecules when a voltage is applied between the pair of transparent electrode layers.
[0004] The light-adjusting sheet has a light-adjusting region where a light-adjusting layer is sandwiched between a pair of electrode sheets, and a non-light-adjusting region where one electrode sheet is exposed from the light-adjusting layer and the other electrode sheet. The non-light-adjusting region is arranged to surround the periphery of the light-adjusting region. A sealant is provided in the non-light-adjusting region to cover the light-adjusting layer located on the edge face of the light-adjusting region (see, for example, Patent Document 1).
[0005] Japanese Patent Application Laid-Open No. 2023-070962
[0006] When viewed from the side opposite the plane on which the light-controlling sheet extends, if a sharp corner where two sides directly intersect is formed at the edge of the light-controlling region, stress tends to concentrate at the sharp corner. Furthermore, the area contributing to the adhesion between the layers that make up the light-controlling sheet is small at the sharp corner. Therefore, peeling starting from the light-controlling layer is likely to occur at the sharp corner formed at the edge of the light-controlling region.
[0007] One aspect provides a light-controlling sheet, the light-controlling sheet comprising: a first electrode sheet having a first transparent electrode layer; a second electrode sheet having a second transparent electrode layer; and a light-controlling layer located between the first and second transparent electrode layers, wherein a portion of the light-controlling layer sandwiched between the first and second electrode sheets forms a light-controlling region, and a portion of the first electrode sheet exposed from the light-controlling layer and the second electrode sheet forms a non-light-controlling region, the light-controlling region having an edge surface located at the boundary with the non-light-control region, the edge surface having, when viewed from a viewpoint opposite to a plane in which the light-controlling sheet extends, a first surface extending in a first direction, a second surface extending in a second direction intersecting the first direction, and a third surface connecting the first surface and the second surface, the third surface having a radius of curvature of 3 mm or more when viewed from the viewpoint.
[0008] FIG. 1 is a plan view of a light-controlling unit equipped with a light-controlling sheet. FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 1. FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 1. FIG. 5 is a schematic diagram showing the configuration of the light-controlling layer. FIG. 6 is an enlarged view of a main part showing a corner portion of the light-controlling sheet. FIG. 7 is a schematic diagram showing the test method for the bending resistance test in the test example. FIG. 8 is a table showing the evaluation results in the test example. FIG. 9 is a cross-sectional view showing a modified example of the light-controlling sheet.
[0009] Hereinafter, one embodiment of a light controlling sheet will be described with reference to Figures 1 to 9. [Light controlling unit 10] As shown in Figure 1, the light controlling unit 10 includes a light controlling sheet 11, a first wiring section 12, and a second wiring section 13. The first wiring section 12 and the second wiring section 13 are, for example, flexible printed circuits (FPCs). The first wiring section 12 and the second wiring section 13 are connected to one edge section 11E of the light controlling sheet 11. The first wiring section 12 and the second wiring section 13 are connected to an external power source (not shown) on the outside of the light controlling sheet 11.
[0010] The light controlling sheet 11 has a substantially rectangular shape with arc-shaped chamfered corners when viewed from a perspective opposite the plane on which the light controlling sheet 11 extends. The light controlling sheet 11 includes a first electrode sheet 20 and a second electrode sheet 30. In Fig. 1 , the first electrode sheet 20 is located on the far side of the page relative to the second electrode sheet 30.
[0011] The light-adjusting sheet 11 includes a light-adjusting region 11A, a first non-light-adjusting region 11B, and a second non-light-adjusting region 11C. The light-adjusting region 11A is a region of the light-adjusting sheet 11 where light transmittance can be changed. The light-adjusting region 11A is surrounded by the first non-light-adjusting region 11B and the second non-light-adjusting region 11C. The first non-light-adjusting region 11B and the second non-light-adjusting region 11C form the outer shape of the light-adjusting sheet 11. In FIG. 1, the light-adjusting region 11A is indicated by a dot.
[0012] The first non-dimming region 11B is formed by the first electrode sheet 20. The first non-dimming region 11B has a first electrode surface 22S. The first electrode surface 22S is the portion of the first electrode sheet 20 that is exposed from the second electrode sheet 30. In FIG. 1 , the first electrode surface 22S faces the front side of the page. The first electrode surface 22S has a first terminal portion 22P. The first wiring portion 12 is connected to the first terminal portion 22P.
[0013] The second non-dimming area 11C is formed by the second electrode sheet 30. The second non-dimming area 11C includes a second electrode surface 32S. The second electrode surface 32S is the portion of the second electrode sheet 30 that is exposed from the first electrode sheet 20. In FIG. 1 , the second electrode surface 32S faces the back side of the page. The second electrode surface 32S includes a second terminal portion 32P. The second wiring portion 13 is connected to the second terminal portion 32P.
[0014] The light controlling sheet 11 has a first corner portion 11R1 and a second corner portion 11R2. The first corner portion 11R1 forms the outer shape of the light controlling sheet 11. In this embodiment, the end face of the first electrode sheet 20 that forms the first non-light controlling region 11B forms the first corner portion 11R1. The second corner portion 11R2 forms the outer shape of the light controlling region 11A along the first corner portion 11R1. The second corner portion 11R2 is formed by the end face of the light controlling region 11A.
[0015] [Cross-sectional structure of light-controlling sheet 11] As shown in Figure 2, the light-controlling sheet 11 includes a first electrode sheet 20, a second electrode sheet 30, and a light-controlling layer 40. The first electrode sheet 20 includes a first transparent substrate 21 and a first transparent electrode layer 22. The second electrode sheet 30 includes a second transparent substrate 31 and a second transparent electrode layer 32. The light-controlling layer 40 is located between the first transparent electrode layer 22 and the second transparent electrode layer 32. In the light-controlling sheet 11, the first transparent substrate 21, the first transparent electrode layer 22, the light-controlling layer 40, the second transparent electrode layer 32, and the second transparent substrate 31 are stacked in this order in the stacking direction.
[0016] The first transparent substrate 21 and the second transparent substrate 31 are optically transparent, i.e., capable of transmitting visible light, and electrically insulating. The material forming the first transparent substrate 21 and the second transparent substrate 31 is an organic polymer compound or an inorganic polymer compound. The organic polymer compound is, for example, at least one selected from the group consisting of polyethylene terephthalate, polyester, polyacrylate, polycarbonate, and polyolefin. The inorganic polymer compound is, for example, at least one selected from the group consisting of silicon dioxide, silicon oxynitride, and silicon nitride. One example of the first transparent substrate 21 and the second transparent substrate 31 is polyethylene terephthalate.
[0017] The first transparent electrode layer 22 and the second transparent electrode layer 32 are electrically conductive and optically transparent, transmitting visible light. The material forming the first transparent electrode layer 22 and the second transparent electrode layer 32 is, for example, at least one selected from the group consisting of indium tin oxide, fluorine-doped tin oxide, tin oxide, zinc oxide, carbon nanotubes, and poly-3,4-ethylenedioxythiophene. One example of the first transparent electrode layer 22 and the second transparent electrode layer 32 is indium tin oxide.
[0018] The light-controlling layer 40 has different light transmittances depending on whether or not a voltage is applied across the first transparent electrode layer 22 and the second transparent electrode layer 32. In this embodiment, when no voltage is applied across the first transparent electrode layer 22 and the second transparent electrode layer 32, the light-controlling layer 40 exhibits an opaque state with low light transmittance. When a voltage is applied across the first transparent electrode layer 22 and the second transparent electrode layer 32, the light-controlling layer 40 exhibits a transparent state with high light transmittance.
[0019] In the light-adjusting region 11A, the light-adjusting layer 40 is sandwiched between the first electrode sheet 20 and the second electrode sheet 30. In other words, the portion of the light-adjusting sheet 11 where the light-adjusting layer 40 is sandwiched between the first electrode sheet 20 and the second electrode sheet 30 forms the light-adjusting region 11A. In the first non-light-adjusting region 11B, the first electrode sheet 20 is exposed from the light-adjusting layer 40 and the second electrode sheet 30. In other words, the portion of the light-adjusting sheet 11 where the first electrode sheet 20 is exposed from the second electrode sheet 30 and the light-adjusting layer 40 forms the first non-light-adjusting region 11B.
[0020] The dimming region 11A includes a first dimming end surface 11A1. The first dimming end surface 11A1 is located at the boundary between the dimming region 11A and the first non-dimming region 11B. That is, the first dimming end surface 11A1 is adjacent to the first non-dimming region 11B. The first dimming end surface 11A1 includes an end surface of the second electrode sheet 30 and an end surface of the dimming layer 40. The first dimming end surface 11A1 may be a flat surface, a curved surface, or a discontinuous surface having steps.
[0021] The first non-dimming region 11B is a portion of the first electrode sheet 20 that protrudes further outward from the dimming sheet 11 than the first dimming end surface 11A1. The first electrode surface 22S provided in the first non-dimming region 11B is a portion of the first transparent electrode layer 22 that is exposed from the second electrode sheet 30 and the dimming layer 40. In other words, the first dimming end surface 11A1 defines the first electrode surface 22S within the first transparent electrode layer 22.
[0022] A sealant 50 is provided on the first electrode surface 22S of the first non-dimming region 11B. The sealant 50 covers the end face of the dimming layer 40 provided in the dimming region 11A. The sealant 50 provided in the first non-dimming region 11B covers the first dimming end face 11A1. The sealant 50 is an insulating resin with hygroscopic properties. The sealant 50 is, for example, an ultraviolet-curable resin. The sealant 50 is formed from, for example, an epoxy resin or an acrylic resin. The sealant 50 prevents the liquid crystal composition 42 (see FIG. 5 ) forming the dimming layer 40 from leaking out from the end face of the dimming layer 40 to the outside.
[0023] 3, the first electrode surface 22S of the first non-dimming region 11B includes a first terminal portion 22P for connecting the first wiring portion 12. The first terminal portion 22P is bonded to the first wiring portion 12 via a conductive adhesive 14 so as to be electrically connected thereto.
[0024] The conductive adhesive 14 is, for example, at least one selected from the group consisting of anisotropic conductive film (ACF), anisotropic conductive paste (ACP), isotropic conductive film (ICF), and isotropic conductive paste (ICP).
[0025] As shown in FIG. 4 , in the second non-dimming region 11C, the second electrode sheet 30 is exposed from the dimming layer 40 and the first electrode sheet 20. In other words, the portion of the dimming sheet 11 where the second electrode sheet 30 is exposed from the dimming layer 40 and the first electrode sheet 20 forms the second non-dimming region 11C. The dimming region 11A has a second dimming end surface 11A2 located at the boundary between the dimming region 11A and the second non-dimming region 11C. That is, the second dimming end surface 11A2 is adjacent to the second non-dimming region 11C. The second dimming end surface 11A2 includes the end surface of the first electrode sheet 20 and the end surface of the dimming layer 40. The second dimming end surface 11A2 may be flat, curved, or a discontinuous surface with steps.
[0026] The second non-dimming region 11C is a portion of the second electrode sheet 30 that protrudes further outward from the dimming sheet 11 than the second dimming end surface 11A2. The second electrode surface 32S provided in the second non-dimming region 11C is a portion of the second transparent electrode layer 32 that is exposed from the first electrode sheet 20 and the dimming layer 40. In other words, the second dimming end surface 11A2 separates the second electrode surface 32S from within the second transparent electrode layer 32. A sealant 50 is provided on the second electrode surface 32S in the second non-dimming region 11C. The sealant 50 provided in the second non-dimming region 11C covers the second dimming end surface 11A2.
[0027] The second electrode surface 32S of the second non-dimming region 11C includes a second terminal portion 32P for connecting the second wiring portion 13. The second terminal portion 32P is bonded to the second wiring portion 13 via a conductive adhesive 14 so as to be electrically connected thereto.
[0028] 5, the light-controlling layer 40 includes an organic polymer layer 41, a liquid crystal composition 42, and spacers 43. The organic polymer layer 41 is a polymer (cured product) formed by polymerizing a photopolymerizable compound. The photopolymerizable compound may be an ultraviolet-curable compound or an electron beam-curable compound. The photopolymerizable compound is compatible with the liquid crystal composition 42.
[0029] The organic polymer layer 41 defines voids 41D within the photochromic layer 40. When it is necessary to improve the controllability of the dimensions of the voids 41D, the photopolymerizable compound is preferably an ultraviolet-curable compound. An example of the ultraviolet-curable compound contains a polymerizable unsaturated bond at the end of the molecular structure. Alternatively, the ultraviolet-curable compound contains a polymerizable unsaturated bond at a position other than the end of the molecular structure. The photopolymerizable compound is one type of polymerizable compound or a combination of two or more types of polymerizable compounds.
[0030] The ultraviolet-curable compound is, for example, at least one selected from the group consisting of acrylate compounds, methacrylate compounds, styrene compounds, thiol compounds, and oligomers of each compound. The acrylate compound is, for example, at least one selected from the group consisting of diacrylate compounds, triacrylate compounds, and tetraacrylate compounds. The acrylate compound is, for example, at least one selected from the group consisting of butyl ethyl acrylate, ethylhexyl acrylate, and cyclohexyl acrylate. The methacrylate compound is, for example, at least one selected from the group consisting of dimethacrylate compounds, trimethacrylate compounds, and tetramethacrylate compounds. The methacrylate compound is, for example, at least one selected from the group consisting of N,N-dimethylaminoethyl methacrylate, phenoxyethyl methacrylate, methoxyethyl methacrylate, and tetrahydrofurfuryl methacrylate. The thiol compound is, for example, at least one selected from the group consisting of 1,3-propanedithiol and 1,6-hexanedithiol. The styrene compound is, for example, at least one selected from the group consisting of styrene and methylstyrene.
[0031] The liquid crystal composition 42 contains a liquid crystal compound LCM and a dichroic dye DP. The liquid crystal composition 42 may further contain a viscosity reducer, an antifoaming agent, an antioxidant, a weathering agent, etc. Examples of weathering agents are ultraviolet absorbers and light stabilizers. The liquid crystal composition 42 is filled into the voids 41D of the organic polymer layer 41.
[0032] The liquid crystal compound LCM includes at least one compound selected from the group consisting of, for example, Schiff base-based, azo-based, azoxy-based, biphenyl-based, terphenyl-based, benzoate ester-based, tolan-based, pyrimidine-based, pyridazine-based, cyclohexanecarboxylic acid ester-based, phenylcyclohexane-based, biphenylcyclohexane-based, dicyanobenzene-based, naphthalene-based, and dioxane-based compounds.
[0033] The liquid crystal compound LCM has a positive dielectric anisotropy, i.e., the dielectric constant in the long axis direction is higher than the dielectric constant in the short axis direction of the liquid crystal compound LCM. Alternatively, the liquid crystal compound LCM has a negative dielectric anisotropy, i.e., the dielectric constant in the long axis direction is lower than the dielectric constant in the short axis direction of the liquid crystal compound LCM. The dielectric anisotropy of the liquid crystal compound LCM is appropriately selected based on the presence or absence of an alignment layer in the light control sheet 11 and the driving type.
[0034] The dichroic dye DP has an elongated molecular shape. The absorbance in the visible region of the dichroic dye DP along the long axis of the molecule is greater than the absorbance along the short axis of the molecule. The dichroic dye DP in this embodiment exhibits a black or near-black color when the long axis of the molecule intersects the incident light direction at a predetermined angle. That is, the dichroic dye DP exhibits a black or near-black color when oriented such that the long axis of the molecule is approximately perpendicular to the normal direction of the contact surface of the light-controlling layer 40 with the first transparent electrode layer 22 and the contact surface with the second transparent electrode layer 32. The dichroic dye DP changes its orientation state when driven by a guest-host system using a liquid crystal compound LCM as a host.
[0035] The dichroic dye DP is, for example, at least one selected from the group consisting of polyiodine, azo compounds, anthraquinone compounds, naphthoquinone compounds, azomethine compounds, tetrazine compounds, quinophthalone compounds, merocyanine compounds, perylene compounds, and dioxazine compounds. The dichroic dye DP is one type of dye or a combination of two or more types of dyes. When it is necessary to improve lightfastness and the dichroic ratio, the dichroic dye DP is preferably at least one selected from the group consisting of azo compounds and anthraquinone compounds, and more preferably an azo compound.
[0036] The type of holding the liquid crystal composition 42 by the organic polymer layer 41 is any one of a group consisting of a polymer dispersion type, a polymer network type, and an encapsulation type, or may be a combination of two or more types from the above groups.
[0037] The organic polymer layer 41 of the polymer-dispersed light-controlling layer 40 defines a large number of isolated voids 41D. The organic polymer layer 41 of the polymer-network light-controlling layer 40 has three-dimensional mesh-like voids 41D. The liquid crystal composition 42 is located in the interconnected mesh-like voids 41D. The organic polymer layer 41 of the capsule-type light-controlling layer 40 has dispersed capsule-like voids 41D. The voids 41D come in two or more sizes. The shape of the voids 41D is spherical, ellipsoidal, or irregular.
[0038] The content of the organic polymer layer 41 relative to the total amount of the organic polymer layer 41 and the liquid crystal composition 42 is preferably 20% by mass or more, and more preferably 30% by mass. The content of the organic polymer layer 41 relative to the total amount of the organic polymer layer 41 and the liquid crystal composition 42 is preferably 70% by mass or less, and more preferably 60% by mass or less.
[0039] The upper and lower limits of the content of the organic polymer layer 41 are determined depending on the range in which the liquid crystal particles made of the liquid crystal composition 42 can be phase-separated from the polymer of the photopolymerizable compound during the polymerization process of the photopolymerizable compound. When it is necessary to increase the mechanical strength of the organic polymer layer 41, it is preferable that the lower limit of the content of the organic polymer layer 41 is high. When it is necessary to reduce the driving voltage of the liquid crystal compound LCM, it is preferable that the upper limit of the content of the organic polymer layer 41 is low.
[0040] The spacers 43 are dispersed throughout the organic polymer layer 41. The spacers 43 determine the thickness of the light-controlling layer 40 around the spacers 43 and make the thickness of the light-controlling layer 40 uniform. The spacers 43 may be bead spacers or photospacers formed by exposing and developing a photoresist. The spacers 43 are translucent. The spacers 43 may be colorless and transparent, or colored and transparent. The color of the colored and transparent spacers 43 is preferably black, which is the same color as the color of the dichroic dye DP.
[0041] In the light-controlling sheet 11, by applying a driving voltage to the first transparent electrode layer 22 and the second transparent electrode layer 32, the orientation of the liquid crystal compound LCM and the dichroic dye DP is controlled in response to changes in the potential difference between the first transparent electrode layer 22 and the second transparent electrode layer 32. The driving voltage is a voltage for changing the orientation state of the liquid crystal compound LCM and the dichroic dye DP. That is, when a driving voltage is applied to the first transparent electrode layer 22 and the second transparent electrode layer 32, the orientation state of the liquid crystal compound LCM and the dichroic dye DP changes, causing the light-controlling layer 40 to switch from one of a transparent state and an opaque state to the other. In the opaque state, the light-controlling layer 40 exhibits a black or near-black color and has a lower total light transmittance than in the transparent state. In other words, the light-controlling sheet 11 in the opaque state has a higher haze, which is the cloudiness value, than in the transparent state.
[0042] In this embodiment, when the application of the driving voltage is removed, the long axis direction of the liquid crystal compound LCM becomes disordered. As a result, the light-switching layer 40 becomes opaque by scattering light across the entire visible light range. Furthermore, when the application of the driving voltage is removed, the long axis direction of the dichroic dye DP also becomes disordered. At least those dichroic dyes DP whose long axis direction forms a predetermined angle, such as an angle close to 90°, with the normal direction of the contact surface of the light-switching layer 40 with the first transparent electrode layer 22 exhibit a black color. Note that the normal direction is the same as the thickness direction of the light-switching layer 40.
[0043] When a driving voltage is applied, the liquid crystal compound LCM is subjected to an orientation control force due to the electric field. At this time, the long axis direction of the liquid crystal compound LCM is aligned along the electric field direction. Similarly, the long axis direction of the dichroic dye DP is also aligned along the electric field direction. This causes the light-controlling layer 40 to enter a transparent state with a higher light transmittance than in the opaque state. Furthermore, the dichroic dye DP follows the movement of the liquid crystal compound LCM, so that its long axis direction is aligned along the electric field direction, and the color of the light-controlling sheet 11 becomes colorless or nearly colorless.
[0044] When the application of the driving voltage is released again, the alignment restriction force exerted by the electric field on the liquid crystal compound LCM and the dichroic dye DP is released. As a result, the long axis directions of the liquid crystal compound LCM and the dichroic dye DP become disordered. As a result, the light-controlling layer 40 scatters light over the entire visible light range, becoming opaque.
[0045] 6, the first corner portion 11R1 and the second corner portion 11R2 have, as an example, a concentric arc shape centered on point P1 when viewed from a viewpoint opposite the plane on which the light controlling sheet 11 extends. Point P1 is located inside the light controlling area 11A when viewed from a viewpoint opposite the plane on which the light controlling sheet 11 extends.
[0046] When viewed from a viewpoint opposite to the plane on which the light controlling sheet 11 extends, the first corner portion 11R1 has a first radius R1. The second corner portion 11R2 has a second radius R2. The second radius R2 is smaller than the first radius R1. Note that the first corner portion 11R1 and the second corner portion 11R2 may be arcs having different centers. In this case, the second radius R2 may be equal to or smaller than the first radius R1.
[0047] The second corner portion 11R2 is formed by the first light control end surface 11A1. The first light control end surface 11A1 has a first surface 11S1, a second surface 11S2, and a third surface 11S3. When viewed from a viewpoint opposite to the plane on which the light control sheet 11 extends, the first surface 11S1 extends in a first direction. The second surface 11S2 extends in a second direction intersecting the first direction. The third surface 11S3 is a curved surface connecting the first surface 11S1 and the second surface 11S2. The third surface 11S3 is a portion of the first light control end surface 11A1 that forms the second corner portion 11R2.
[0048] When viewed from a viewpoint opposite the plane on which the light controlling sheet 11 extends, in the light controlling region 11A, the angle formed by the imaginary plane including the first surface 11S1 and the imaginary plane including the second surface 11S2 is greater than 0 degrees and less than 180 degrees. In other words, when viewed from a viewpoint opposite the plane on which the light controlling sheet 11 extends, in the second corner portion 11R2, the imaginary plane including the first surface 11S1 and the imaginary plane including the second surface 11S2 form a minor angle toward the light controlling region 11A.
[0049] The second radius R2 of the third surface 11S3 is 3 mm or more when viewed from a perspective opposite the plane on which the light-controlling sheet 11 extends. The second radius R2 may be the radius of the edge portion of the second electrode sheet 30 located on the third surface 11S3 at the outermost position in the stacking direction. The edge portion of the second electrode sheet 30 refers to the upper end portion of the second transparent substrate 31 that forms the first light-controlling end surface 11A1 in FIG. 2 . The second radius R2 may also be the radius of the edge portion of the light-controlling layer 40 that is located on the third surface 11S3 closest to the first electrode sheet 20 in the stacking direction. The edge portion of the light-controlling layer 40 refers to the lower end portion of the light-controlling layer 40 that forms the first light-controlling end surface 11A1 in FIG. 2 . In addition, the second radius R2 may be the average value of the radius of the edge portion of the second electrode sheet 30 that is located on the outermost side of the third surface 11S3 in the stacking direction and the radius of the edge portion of the dimming layer 40 that is located on the third surface 11S3 closest to the first electrode sheet 20 in the stacking direction.
[0050] If the first dimming end surface 11A1 were to have a steep second corner 11R2 where the first surface 11S1 and the second surface 11S2 directly intersect without providing the third surface 11S3, the adhesion area between the dimming layer 40 and the first transparent electrode layer 22 would be small at the second corner 11R2. Therefore, if a steep second corner 11R2 where the first surface 11S1 and the second surface 11S2 directly intersect is formed, the second corner 11R2 would likely become the starting point for interlayer peeling between the dimming layer 40 and the first transparent electrode layer 22 when an external force such as bending is applied. In addition, if a steep second corner 11R2 is formed on the first dimming end surface 11A1, other objects would likely get caught on the second corner 11R2, making it easier for external forces to be applied to the second corner 11R2.
[0051] In this regard, in the present embodiment, the first surface 11S1 and the second surface 11S2 are connected by the third surface 11S3, which is an arc-shaped curved surface having a second radius R2 of 3 mm or more. This makes it possible to prevent the formation of a portion where the adhesive area between the light-control layer 40 and the first transparent electrode layer 22 is reduced at the second corner portion 11R2, which is the connection portion between the first surface 11S1 and the second surface 11S2. Furthermore, because other objects are less likely to get caught on the second corner portion 11R2, which is the connection portion between the first surface 11S1 and the second surface 11S2, it is possible to prevent external forces from being applied to the connection portion.
[0052] In particular, when the photochromic layer 40 includes black spacers 43 and black dichroic dye DP as in this embodiment, the spacers 43 and the dichroic dye DP absorb light irradiated to the photopolymerizable compound, which is the precursor of the organic polymer layer 41, and this tends to reduce the mechanical strength of the photochromic layer 40. In this regard, by connecting the first surface 11S1 and the second surface 11S2 with the third surface 11S3, it is possible to suitably suppress the occurrence of peeling starting from the second corner portion 11R2, which is the connection portion between the first surface 11S1 and the second surface 11S2, even when the photochromic layer 40 includes black spacers 43 and black dichroic dye DP.
[0053] When the light-adjusting unit 10 is attached to a glass window, the outer periphery of the light-adjusting sheet 11 is covered by a window sash or the like. In this case, it is preferable that the first non-light-adjusting region 11B and other portions of the light-adjusting sheet 11, whose light transmittance cannot be changed, be completely concealed by the window sash or the like. However, if the second radius R2 of the third surface 11S3 is excessively large, the first non-light-adjusting region 11B, which is located outside the light-adjusting region 11A, tends to extend beyond the rectangular window sash or the like. In this case, light is not adjusted in the first non-light-adjusting region 11B extending beyond the window sash, which is undesirable from the standpoint of functionality and design. For example, when using a window sash (window frame) with a width of 20 mm extending inward from the light-adjusting sheet 11, the second radius R2 of the third surface 11S3 is preferably 50 mm or less to prevent the first non-light-adjusting region 11B from extending beyond the window sash.
[0054] [Method for manufacturing dimming unit 10] The method for manufacturing the dimming unit 10 includes the steps of manufacturing the dimming sheet 11, attaching the first wiring section 12 and the second wiring section 13 to the dimming sheet 11, and providing the sealing material 50 on the dimming sheet 11.
[0055] In one example of a method for manufacturing the light-controlling sheet 11, first, a first electrode sheet 20 and a second electrode sheet 30 are prepared. Next, a coating film for forming the light-controlling layer 40 is formed between the first transparent electrode layer 22 and the second transparent electrode layer 32 of the first electrode sheet 20.
[0056] The coating film contains a photopolymerizable compound, a liquid crystal composition 42, and a polymerization initiator for initiating polymerization of the photopolymerizable compound. The polymerization initiator is at least one selected from the group consisting of diketone compounds, acetophenone compounds, benzoin compounds, benzophenone compounds, and thioxanthone compounds. The polymerization initiator may be a single compound or a combination of two or more compounds. The polymerization initiator is, for example, at least one selected from the group consisting of benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and cyclohexyl phenyl ketone. Spacers 43 are also dispersed in the coating film.
[0057] The manufacturing method of the light-controlling sheet 11 includes polymerizing the photopolymerizable compound in the coating film, thereby phase-separating the liquid crystal particles made of the liquid crystal composition 42 from the photopolymerizable compound. The light that polymerizes the photopolymerizable compound may be irradiated toward the first electrode sheet 20, may be irradiated toward the second electrode sheet 30, or may be irradiated toward both the first electrode sheet 20 and the second electrode sheet 30. In this way, a laminate including the first electrode sheet 20, the second electrode sheet 30, and the light-controlling layer 40 is manufactured.
[0058] Next, a cutting plotter is used to cut the outline of the laminate so that the outlines of the first electrode sheet 20 and the second electrode sheet 30 match. This forms the outline of the light controlling sheet 11, including the edge 11E and first corner 11R1 of the light controlling sheet 11. At this time, by forming the first corner 11R1 into an arc-shaped curved surface, each side that forms the outline of the light controlling sheet 11 can be cut in a single continuous cutting operation.
[0059] Next, a cutting plotter is used to half-cut and remove a portion of the second electrode sheet 30 together with the overlapping portion of the light-controlling layer 40. This exposes the first electrode surface 22S in the laminate and forms the first light-controlling end surface 11A1. That is, the first non-light-controlling region 11B is formed in the laminate.
[0060] By forming the third surface 11S3 of the first dimming end surface 11A1 as an arc-shaped curved surface, the first surface 11S1, the second surface 11S2, and the third surface 11S3 of the first dimming end surface 11A1 can be cut in a single continuous cutting operation. Furthermore, as shown in FIG. 1 , by forming corners of the first dimming end surface 11A1 other than the third surface 11S3 (second corner 11R2) as arc-shaped curved surfaces, the entire first dimming end surface 11A1 can be cut in a single continuous cutting operation. The corners other than the third surface 11S3 refer to corners located near the first terminal 22P or near the boundary between the first non-dimming region 11B and the second non-dimming region 11C.
[0061] Next, a cutting plotter is used to half-cut and remove a portion of the first electrode sheet 20 together with the overlapping portion of the dimming layer 40. This exposes the second electrode surface 32S in the laminate, and forms a second dimming end surface 11A2. That is, a second non-dimming region 11C is formed in the laminate. At this time, as shown in FIG. 1 , by forming each corner of the second dimming end surface 11A2 into an arc-shaped curved surface, each side of the second dimming end surface 11A2 can be cut in a single continuous cutting operation.
[0062] Next, the first wiring section 12 and the second wiring section 13 are attached to the light-adjusting sheet 11. Then, a sealant 50 is provided in the first non-light-adjusting region 11B and the second non-light-adjusting region 11C so as to cover the end faces of the light-adjusting layer 40 exposed from the first light-adjusting end face 11A1 and the second light-adjusting end face 11A2. In this manner, the light-adjusting unit 10 is manufactured.
[0063] In the above manufacturing process, from the viewpoint of suitably removing the first electrode sheet 20 and the light-changing layer 40 by half-cutting, and removing the second electrode sheet 30 and the light-changing layer 40, it is preferable that the peel strength between the adjacent layer in contact with the light-changing layer 40 and the light-changing layer 40 be less than a predetermined threshold. For example, it is preferable that the peel strength in the 180° direction between the adjacent layer in contact with the light-changing layer 40 and the light-changing layer 40, as measured in accordance with JIS Z-0237:2022, is less than 8 N / 25 mm. In this embodiment, the first transparent electrode layer 22 and the second transparent electrode layer 32 correspond to adjacent layers.
[0064] That is, in this embodiment, by setting an upper limit on the peel strength for half-cutting, it is possible to preferably remove unnecessary portions by half-cutting. Also, because there is an upper limit on the peel strength for the reasons described above, there is a limit to how much interlayer delamination in the light control region 11A can be suppressed by increasing the peel strength. Therefore, in this embodiment, the first surface 11S1 and the second surface 11S2 are connected by the third surface 11S3 to suppress the occurrence of interlayer delamination in the light control region 11A.
[0065] The peel strength between the photochromic layer 40 and an adjacent layer in contact with the photochromic layer 40 can be controlled by adjusting at least one of the type of photopolymerizable compound that is the precursor of the organic polymer layer 41, the composition of each component that forms the photochromic layer 40, and the exposure conditions of the photochromic layer 40. For example, to increase the peel strength, the intensity of the exposure light may be increased or the exposure time may be extended. For example, to decrease the peel strength, the intensity of the exposure light may be decreased or the exposure time may be shortened.
[0066] [Test Example] Below, with reference to Figures 7 and 8, the relationship between the second radius R2 of the third surface 11S3 and the characteristics of the light-controlling sheet 11, and the relationship between the peel strength between the adjacent layer in contact with the light-controlling layer 40 and the light-controlling layer 40 and the characteristics of the light-controlling sheet 11 will be described.
[0067] In the test example, 12 levels of samples, Sample A to Sample L, were prepared. For Sample A to Sample L, a light-controlling sheet 11 was prepared that included a first electrode sheet 20, a second electrode sheet 30, and a light-controlling layer 40. For Sample A to Sample L, the light-controlling sheet 11 had a rectangular outer shape in plan view. For Sample A to Sample L, a light-controlling layer 40 was formed that included an organic polymer layer 41, a liquid crystal composition 42 containing a liquid crystal compound LCM and a black dichroic dye DP, and black spacers 43.
[0068] For each sample, the exposure conditions of the photochromic layer 40 were controlled so that the peel strength in the 180° direction, measured in accordance with JIS Z-0237:2022, was 0.2 N / 25 mm for samples A to J, 7 N / 25 mm for sample K, and 8 N / 25 mm for sample L. The peel strength of each sample was measured using a small desktop testing machine (product name: EZ-LX) manufactured by Shimadzu Corporation under conditions of a sample width of 25 mm and a peel speed of 300 mm / min.
[0069] In Samples A to L, the size of the second radius R2 of the third surface 11S3 was changed to produce the light-controlling sheet 11. The laminate including the first electrode sheet 20, the second electrode sheet 30, and the light-controlling layer 40 was half-cut using a cutting plotter.
[0070] The second radius R2 was 0 mm, 2 mm, 3 mm, 5 mm, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, and 60 mm in the order of samples A to J. The second radius R2 was 5 mm in samples K and L. Note that the value of 0 mm in sample A means that the third surface 11S3 was not formed in the second corner portion 11R2, and a steep second corner portion 11R2 was formed so that the first surface 11S1 and the second surface 11S2 directly intersected each other.
[0071] For sample L, when an attempt was made to peel off the half-cut portion using a cutting plotter, the half-cut portion could not be peeled off from the laminate. Furthermore, for samples B to K, which were processed into an arc shape by half-cutting using a cutting plotter, a visual inspection of the processing accuracy of the arc shape was performed. For sample B, which had a second radius R2 of 2 mm, it was confirmed that the arc shape of the third surface 11S3 was distorted (evaluation result: poor). For samples C to K, it was confirmed that the arc shape of the third surface 11S3 was formed with sufficient accuracy (evaluation result: good). The evaluation results of the visual inspection are shown in Figure 8.
[0072] As shown in Figure 7, in this test example, a bending resistance test was conducted on Samples A to K, which were capable of being half-cut. In the bending resistance test, the region of each sample extending 15 mm from the end toward the inside of the sheet was pressed against the outer surface of a rod 100 having a diameter of 5 mm and held for 10 seconds. After that, each sample was checked for the presence or absence of peeling in the photochromic layer 40 near the first photochromic end surface 11A1 of the photochromic region 11A. The evaluation results of the bending resistance test are shown in Figure 8.
[0073] In this test example, samples A to K were also tested for designability. In the designability test, each sample was fitted into a window frame 20 mm wide facing inward of the light-adjusting sheet 11, and it was confirmed whether the first non-light-adjusting region 11B or the second non-light-adjusting region 11C, other than the light-adjusting region 11A, protruded. The evaluation results of the designability test are shown in Figure 8.
[0074] As shown in FIG. 8 , no delamination was observed in Samples A to K subjected to the bending resistance test before the bending resistance test. In Sample A after the bending resistance test, delamination of the switchable layer 40 was observed near the second corner 11R2 formed by the first surface 11S1 and the second surface 11S2. In Sample B after the bending resistance test, delamination of the switchable layer 40 was observed near the third surface 11S3. On the other hand, no delamination was observed in Samples C to K after the bending resistance test. Therefore, it was confirmed that by setting the second radius R2 of the third surface 11S3 to 3 mm or more, it is possible to suppress the occurrence of delamination originating from the connection portion between the first surface 11S1 and the second surface 11S2.
[0075] As shown in Figure 8, in the design test, in Samples A to I and K, the first non-dimming region 11B and the second non-dimming region 11C, other than the dimming region 11A, were covered and concealed without protruding from the window frame. That is, in Samples A to I and K, only the dimming region 11A was exposed from the window frame. On the other hand, in Sample J, a portion of the first non-dimming region 11B protruded from the corner of the window frame. Therefore, it was confirmed that by setting the second radius R2 of the third surface 11S3 to 50 mm or less, it is possible to prevent the first non-dimming region 11B from protruding from the window frame, which has a width of 20 mm toward the inside of the dimming sheet 11.
[0076] Advantages of the embodiment (1) By connecting the first surface 11S1 and the second surface 11S2 by the curved third surface 11S3, it is possible to suppress the occurrence of peeling that starts from the second corner portion 11R2, which is the connection portion between the first surface 11S1 and the second surface 11S2. Furthermore, by having the third surface 11S3 have the second radius R2 of 3 mm or more, it is possible to process the shape of the third surface 11S3 with high precision so as to preferably realize the above-mentioned advantages.
[0077] (2) By connecting the first surface 11S1 and the second surface 11S2 with the curved third surface 11S3, each side of the first surface 11S1, the second surface 11S2, and the third surface 11S3 can be continuously cut by a series of cutting operations.
[0078] (3) By setting the second radius R2 of the third surface 11S3 to 50 mm or less, when the outer edge of the dimming unit 10 is covered by a rectangular window sash or the like, the first non-dimming area 11B is less likely to extend beyond the window sash.
[0079] (4) The photochromic layer 40 is formed so that the peel strength in the 180° direction measured in accordance with JIS Z-0237:2022 between the photochromic layer 40 and an adjacent layer in contact with the photochromic layer 40 is less than 8 N / 25 mm. This makes it easy to remove the first electrode sheet 20 and the photochromic layer 40 by half-cutting, and to remove the second electrode sheet 30 and the photochromic layer 40. Furthermore, even if there is an upper limit to the peel strength, the advantage of (1) makes it possible to suitably suppress peeling.
[0080] (5) When the photochromic layer 40 includes black spacers 43 and a black dichroic dye DP, as in the present embodiment, the spacers 43 and the dichroic dye DP tend to absorb light irradiated onto the photopolymerizable compound, which is the precursor of the organic polymer layer 41. Therefore, when the photochromic layer 40 includes black spacers 43 and a black dichroic dye DP, the mechanical strength of the photochromic layer 40 tends to be reduced. Thus, even when the photochromic layer 40 includes black spacers 43 and a black dichroic dye DP, connecting the first surface 11S1 and the second surface 11S2 with the third surface 11S3 can effectively suppress peeling that originates from the second corner portion 11R2, which is the connection portion between the first surface 11S1 and the second surface 11S2.
[0081] (6) A first non-dimming region 11B is provided around the dimming region 11A for providing a sealant 50 that covers the edge of the dimming layer 40. The second corner 11R2 at the boundary between the dimming region 11A and the first non-dimming region 11B is formed by a curved third surface 11S3. Therefore, while providing the first non-dimming region 11B for providing the sealant 50 around the dimming region 11A, it is possible to prevent peeling from occurring at the second corner 11R2 at the boundary between the dimming region 11A and the first non-dimming region 11B.
[0082] [Modifications] The above embodiment can be modified as follows: The modifications can be combined within the scope of technical compatibility.
[0083] As shown in Fig. 9 , the light-controlling sheet 11 may include a first alignment layer 61 and a second alignment layer 62. The first alignment layer 61 is sandwiched between the first transparent electrode layer 22 and the light-controlling layer 40. The second alignment layer 62 is sandwiched between the second transparent electrode layer 32 and the light-controlling layer 40. In this case, the first alignment layer 61 and the second alignment layer 62 correspond to adjacent layers in contact with the light-controlling layer 40. That is, the adjacent layers in contact with the light-controlling layer 40 may be the first transparent electrode layer 22 and the second transparent electrode layer 32 as in the above embodiment, or may be the first alignment layer 61 and the second alignment layer 62 as in the example of Fig. 9 .
[0084] In the dimming region 11A, the first alignment layer 61 and the second alignment layer 62, which sandwich the dimming layer 40, are sandwiched between the first electrode sheet 20 and the second electrode sheet 30. In other words, the portion where the first alignment layer 61 and the second alignment layer 62, which sandwich the dimming layer 40, are sandwiched between the first electrode sheet 20 and the second electrode sheet 30 forms the dimming region 11A. In the first non-dimming region 11B, the first electrode sheet 20 is exposed from the first alignment layer 61, the dimming layer 40, the second alignment layer 62, and the second electrode sheet 30. In other words, the portion of the first electrode sheet 20 that is exposed from the first alignment layer 61, the dimming layer 40, the second alignment layer 62, and the second electrode sheet 30 forms the first non-dimming region 11B. In the second non-dimming region 11C, the second electrode sheet 30 is exposed from the first alignment layer 61, the dimming layer 40, the second alignment layer 62, and the first electrode sheet 20. In other words, the portion of the second electrode sheet 30 that is exposed from the first alignment layer 61, the dimming layer 40, the second alignment layer 62, and the first electrode sheet 20 forms the second non-dimming region 11C.
[0085] The first alignment layer 61 and the second alignment layer 62 are vertical alignment films that regulate the alignment direction of the liquid crystal compound LCM so that the alignment direction of the liquid crystal compound LCM is along the stacking direction of the light-controlling sheet 11. The first alignment layer 61 and the second alignment layer 62 are visually recognized as colorless and transparent or colored and transparent, respectively.
[0086] The materials forming the first alignment layer 61 and the second alignment layer 62 are organic polymer compounds or inorganic oxides. The organic polymer compounds are, for example, at least one selected from the group consisting of polyimide, polyamide, and polyvinyl alcohol. The inorganic oxides are, for example, at least one selected from the group consisting of silicon oxide, zirconium oxide, and silicone (organosilicon compounds).
[0087] When no voltage is applied between the first transparent electrode layer 22 and the second transparent electrode layer 32, the alignment state of the liquid crystal compound LCM follows the alignment restricting force of the first alignment layer 61 and the second alignment layer 62. The alignment state of the liquid crystal compound LCM following the alignment restricting force allows visible light to transmit through the light control layer 40. This makes the light control sheet 11 transparent.
[0088] When a voltage is applied between the first transparent electrode layer 22 and the second transparent electrode layer 32, the liquid crystal compound LCM is subjected to the action force of an electric field that resists the alignment restriction force. The alignment state of the liquid crystal compound LCM according to the action force of the electric field causes the light control layer 40 to scatter visible light. This makes the light control sheet 11 opaque.
[0089] When the light-controlling sheet 11 includes a first alignment layer 61 and a second alignment layer 62, the step at the boundary between the light-controlling region 11A and the first non-light-controlling region 11B increases in proportion to the number of layers forming the light-controlling region 11A. In other words, the width (height) of the first light-controlling end surface 11A1 of the light-controlling region 11A increases in the stacking direction of the light-controlling sheet 11. This makes it easier for other objects to get caught on the end surface of the light-controlling region 11A. In this regard, connecting the first surface 11S1 and the second surface 11S2 with the third surface 11S3 makes it less susceptible to external forces from other objects than when a steep second corner 11R2 is formed so that the first surface 11S1 and the second surface 11S2 directly intersect.
[0090] The light-controlling sheet 11 may include other functional layers such as an ultraviolet-shielding layer, an infrared-shielding layer, an adhesive layer, a protective layer, etc., in addition to the first alignment layer 61 and the second alignment layer 62. The light-controlling sheet 11 is not limited to a rectangular shape, and may have a geometric shape other than a rectangular shape, such as a polygonal shape, a circular shape, or an elliptical shape, or may have an irregular shape other than a geometric shape.
[0091] The sealant 50 may be omitted in part or all of the first non-dimming region 11B and the second non-dimming region 11C. For example, when caulking is used when attaching the dimming unit 10 to an attachment target, the first dimming end surface 11A1 and the second dimming end surface 11A2 may be covered with a caulking agent instead of the sealant 50.
[0092] The photochromic layer 40 does not necessarily have to include the dichroic dye DP. In this case, the photochromic layer 40 exhibits white color in the opaque state. Alternatively, the photochromic layer 40 may include a dichroic dye DP that exhibits a color other than black in the opaque state. Similarly, the color of the spacer 43 is not limited and may be colorless and transparent, or may be a colored and transparent color other than black.
[0093] - If the removal of the first electrode sheet 20 and the light-changing layer 40 by half-cutting, and the removal of the second electrode sheet 30 and the light-changing layer 40 can be performed smoothly, the peel strength between the adjacent layer in contact with the light-changing layer 40 and the light-changing layer 40 may be 8 N / 25 mm or more.
[0094] The upper limit of the second radius R2 of the third surface 11S3 may be determined appropriately depending on the shape of the window sash, etc. The third surface 11S3 is not limited to a configuration in which it is an arc having a constant second radius R2 when viewed from a viewpoint opposite to the plane on which the light controlling sheet 11 extends. For example, the radius of curvature of each portion of the third surface 11S3 may be 3 mm or more. In other words, the radius of curvature may be 3 mm or more over the entire length of the third surface 11S3. For example, it is more preferable that the radius of curvature of each portion of the third surface 11S3 is 50 mm or less. Note that the third surface 11S3 may include a portion with a radius of curvature greater than 50 mm as long as this does not affect the design or functionality of the light controlling unit 10 when attached to an attachment target.
[0095] In the above embodiment, the light control layer 40 has a structure including the organic polymer layer 41 and the liquid crystal composition 42. Alternatively, the light control layer 40 may change its light transmittance using a suspended particle device (SPD) method that includes light control particles as oriented particles. The SPD method is a method in which a light control suspension containing light control particles is dispersed in a resin matrix.
[0096] The first wiring portion 12 and the second wiring portion 13 may be formed of a flexible flat cable (FFC) instead of a flexible printed circuit board. A flexible flat cable has a structure in which parallel-arranged strip-shaped conductors are sandwiched between two insulating resin substrates. At the end of the flexible flat cable, the strip-shaped conductors are exposed from the resin substrates. The exposed portions of the conductors are connected to the first electrode surface 22S and the second electrode surface 32S. The first wiring portion 12 and the second wiring portion 13 may also be conductive tape members such as copper tape.
Claims
1. A light-controlling sheet comprising: a first electrode sheet having a first transparent electrode layer; a second electrode sheet having a second transparent electrode layer; and a light-controlling layer located between the first transparent electrode layer and the second transparent electrode layer; a portion of the light-controlling layer sandwiched between the first electrode sheet and the second electrode sheet forms a light-controlling region; a portion of the first electrode sheet exposed from the light-controlling layer and the second electrode sheet forms a non-light-controlling region; the light-controlling region has an end face located at the boundary with the non-light-control region; and the end face comprises, when viewed from a viewpoint opposite to the plane in which the light-controlling sheet extends, a first surface extending in a first direction, a second surface extending in a second direction intersecting the first direction, and a third surface connecting the first surface and the second surface; and the third surface has a radius of curvature of 3 mm or more when viewed from the viewpoint.
2. The light-controlling sheet according to claim 1, wherein the third surface has a radius of curvature of 50 mm or less when viewed from the viewpoint.
3. The light-controlling sheet according to claim 1, wherein the peel strength in the 180° direction between the light-controlling layer and an adjacent layer in contact with the light-controlling layer is less than 8 N / 25 mm as measured in accordance with JIS Z-0237:2022.
4. The light-controlling layer comprises an organic polymer layer having a plurality of voids, a liquid crystal composition filled in the voids, and spacers exhibiting a black color, the organic polymer layer being formed by polymerizing a photopolymerizable compound, the liquid crystal composition including a liquid crystal compound and a dichroic dye, the light-controlling layer switching from a black opaque state to a transparent state by changing the orientation of the liquid crystal compound and the dichroic dye in response to a change in the potential difference between the first transparent electrode layer and the second transparent electrode layer, and the dichroic dye exhibiting a black color in the opaque state. A light-controlling sheet as described in claim 1.
5. The light-controlling layer according to claim 1, comprising an organic polymer layer having a plurality of voids and a liquid crystal composition filling the voids; and further comprising a first alignment layer sandwiched between the first transparent electrode layer and the light-controlling layer; and a second alignment layer sandwiched between the second transparent electrode layer and the light-controlling layer; the portion of the first alignment layer and the second alignment layer sandwiching the light-controlling layer between the first electrode sheet and the second electrode sheet forms the light-controlling region; and the portion of the first electrode sheet exposed from the first alignment layer, the light-controlling layer, the second alignment layer, and the second electrode sheet forms the non-light-controlling region.
6. The light-modulating sheet according to claim 1, wherein a sealing material is provided in the non-light-modulating region to cover the end faces.
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