Light control film

Abstract

The present invention provides a light control film comprising a first transparent conductive film, a light control layer including a polymer matrix and a liquid crystal component, and a second transparent conductive film in the stated order, wherein the first transparent conductive film includes a first transparent substrate and a first transparent electrode layer disposed on the light control layer side of the first transparent substrate, the second transparent conductive film includes a second transparent substrate and a second transparent electrode layer disposed on the light control layer side of the second transparent substrate, at least a part of an outer peripheral end part of the light control film is provided with a notch part formed by notching from the first transparent substrate to a part of the light control layer side of the second transparent substrate, and a sealing part covering end surfaces of the light control layer and the second transparent conductive film in the notch part is provided.

Description

Light-controlling film

[0001] The present invention relates to a light management film.

[0002] A light-controlling film having a pair of transparent conductive films and a light-controlling layer disposed between them, the light-controlling layer containing a polymer matrix and a liquid crystal component, can change the orientation of the liquid crystal component depending on the potential difference between the pair of transparent conductive films, thereby changing the degree of scattering of transmitted light.

[0003] With regard to the above-mentioned light-controlling film, it has been proposed to provide a sealing portion that seals the end faces of the light-controlling layer in order to prevent deterioration of the liquid crystal component due to moisture, ultraviolet rays, etc., and leakage of the liquid crystal component (Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2020-177039

[0005] The sealing portion that seals the end face of the light-control layer may have insufficient adhesion to the end face. A main object of the present invention is to provide a light-control film that has excellent adhesion to the sealing portion.

[0006] [1] According to one aspect of the present invention, there is provided a light control film comprising, in this order: a first transparent conductive film, a light control layer comprising a polymer matrix and a liquid crystal component, and a second transparent conductive film, wherein the first transparent conductive film comprises a first transparent substrate and a first transparent electrode layer disposed on the light control layer side of the first transparent substrate, and the second transparent conductive film comprises a second transparent substrate and a second transparent electrode layer disposed on the light control layer side of the second transparent substrate, and wherein at least a portion of the outer peripheral edge of the light control film is provided with a cutout portion extending from the first transparent substrate to a portion of the second transparent substrate on the light control layer side, and a sealing portion is provided to cover the edge faces of the light control layer and the second transparent conductive film at the cutout portion. [2] In a cut surface along the thickness direction of the light control film described in [1] above, the length of the edge face of the second transparent conductive film at the cutout portion may be 1 μm or more. [3] In a cut surface along the thickness direction of the light control film described in [1] or [2] above, the contact length between the sealing portion and the second transparent conductive film may be 100 μm or more. [4] The light control film described in any of [1] to [3] above may have a polygonal shape, and the sealing portion may be provided on at least one edge thereof. [5] The light control film described in any of [1] to [4] above may have a quadrangular shape, and the sealing portion may be provided on three edges excluding the edge to which wiring is connected.

[0007] According to an embodiment of the present invention, a cutout is provided at the end of the light control film, and a sealing portion that seals the end face of the light control layer is provided in the cutout. In this case, by cutting out from the first transparent substrate to at least a part of the second transparent substrate, the contact area and / or adhesion strength between the light control film and the sealing portion can be increased.

[0008] FIG. 1 is a schematic top view of a light management film according to one embodiment of the present invention. FIG. 2 is a schematic bottom view of the light management film shown in FIG. 1. FIG. 3 is a schematic cross-sectional view of the light management film shown in FIG. 1 taken along line III-III. FIG. 4 is a schematic cross-sectional view showing a modified example of a sealing portion. FIG. 5 is a schematic cross-sectional view showing a modified example of a sealing portion. FIG. 6 is a schematic cross-sectional view showing a modified example of a sealing portion. FIG. 7 is a schematic cross-sectional view showing a modified example of a sealing portion. FIG. 8 is a schematic view illustrating an example of a method for manufacturing a light management film. FIG. 9 is a schematic cross-sectional view of the light management film shown in FIG. 1 taken along line VI-VI. FIG. 10 is a schematic cross-sectional view of the light management film shown in FIG. 1 taken along line VII-VII. FIG. 11 is a micrograph of the cross section of the edge of a PDLC film with a sealing portion formed on the periphery.

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. In order to clarify the description, the drawings may schematically show the width, thickness, shape, etc. of each part compared to the embodiments, but these are merely examples and do not limit the interpretation of the present invention. Furthermore, in the drawings, the same or equivalent elements are given the same reference numerals, and duplicate explanations may be omitted.

[0010] A. Light Control Film According to an embodiment of the present invention, there is provided a light control film comprising, in this order: a first transparent conductive film; a light control layer comprising a polymer matrix and a liquid crystal component; and a second transparent conductive film, wherein the first transparent conductive film comprises a first transparent substrate and a first transparent electrode layer arranged on the light control layer side of the first transparent substrate; the second transparent conductive film comprises a second transparent substrate and a second transparent electrode layer arranged on the light control layer side of the second transparent substrate; and a cutout portion is provided in at least a portion of the outer peripheral edge of the light control film, the cutout portion extending from the first transparent substrate to a portion of the second transparent substrate on the light control layer side; and a sealing portion is provided to cover the edge surfaces of the light control layer and the second transparent conductive film in the cutout portion.

[0011] Hereinafter, a light management film according to an embodiment of the present invention will be described with reference to Figures 1 to 7. Figure 1 is a schematic top view of a light management film according to one embodiment of the present invention, Figure 2 is a schematic bottom view of the light management film shown in Figure 1, and Figures 3, 6, and 7 are schematic cross-sectional views of the light management film taken along lines III-III, VI-VI, and VII-VII, respectively. In this specification, when referring to the up-down direction, unless otherwise specified, the first transparent conductive film side of the light management film is the upper side, and the second transparent conductive film side is the lower side.

[0012] 1 and 2, the light control film 100 has a rectangular shape in a plan view. Of the four ends (edges) 100a-d of the light control film 100, three ends 100a-c are entirely provided with a sealing portion 40, and a portion of the remaining end 100d is provided with a sealing portion 40. Wiring 200A and 200B for driving the light control film 100 are connected to the portion of end 100d where the sealing portion 40 is not provided.

[0013] 3 , the light control film 100 includes, in this order, a first transparent conductive film 10, a light control layer 20, and a second transparent conductive film 30. The first transparent conductive film 10 includes a first transparent substrate 12 and a first transparent electrode layer 14 arranged on the light control layer 20 side of the first transparent substrate 12. The second transparent conductive film 30 includes a second transparent substrate 32 and a second transparent electrode layer 34 arranged on the light control layer 20 side of the second transparent substrate 32. The light control layer 20 includes a polymer matrix and a liquid crystal component, and can change the orientation state of the liquid crystal component in response to the potential difference between the first transparent electrode layer 14 and the second transparent electrode layer 34.

[0014] The surface resistance value of the first transparent conductive film 10 is preferably 1 Ω / □ to 1000 Ω / □, more preferably 5 Ω / □ to 300 Ω / □, and even more preferably 10 Ω / □ to 200 Ω / □.

[0015] The haze value of the first transparent conductive film is preferably 20% or less, more preferably 10% or less, and even more preferably 0.1% to 10%.

[0016] The total light transmittance of the first transparent conductive film is preferably 40% or more, more preferably 60% or more, and even more preferably 80% or more.

[0017] The first transparent substrate 12 is typically a polymer film containing a thermoplastic resin as a main component, such as a polyester resin, a cycloolefin resin such as polynorbornene, an acrylic resin, a polycarbonate resin, or a cellulose resin.

[0018] The thickness of the first transparent substrate is preferably 10 μm to 200 μm, more preferably 20 μm to 150 μm, and even more preferably 30 μm to 100 μm.

[0019] The first transparent electrode layer 14 may be made of, for example, indium tin oxide (ITO), zinc oxide (ZnO), or tin oxide (SnO ２ The first transparent electrode layer may be formed using a metal oxide such as ZnO. In this case, the metal oxide may be an amorphous metal oxide or a crystallized metal oxide. The first transparent electrode layer may also be formed using metal nanowires such as silver nanowires (AgNW), carbon nanotubes (CNT), an organic conductive film, a metal layer, or a laminate thereof. Preferably, a transparent electrode layer containing ITO is formed. A transparent electrode layer containing ITO has excellent transparency. The first transparent electrode layer may be patterned into a desired shape depending on the purpose.

[0020] The thickness of the first transparent electrode layer is, for example, 10 nm or more, preferably 15 nm or more, and for example, 50 nm or less, preferably 35 nm or less, more preferably 30 nm or less.

[0021] The first transparent electrode layer is formed on one surface of the first transparent substrate by, for example, sputtering. After forming the metal oxide layer by sputtering, it can be crystallized by annealing. Annealing is performed by, for example, heat treatment at 120°C to 300°C for 10 to 120 minutes.

[0022] The light-controlling layer 20 includes a polymer matrix and a liquid crystal component. Preferred examples of the light-controlling layer include a polymer dispersed liquid crystal (PDLC) layer and a polymer network liquid crystal (PNLC) layer. The PDLC layer has a structure in which droplets of the liquid crystal component are dispersed in a polymer matrix. The PNLC layer has a continuous structure in which the liquid crystal component is filled into the gaps in a network-like polymer matrix.

[0023] Examples of the polymer matrix-forming resin include thermoplastic resins such as urethane-based resins, polyvinyl alcohol-based resins, polyethylene-based resins, polypropylene-based resins, and acrylic-based resins. Other examples of the polymer matrix-forming resin include curable resins such as liquid crystal polymers, (meth)acrylic-based resins, silicone-based resins, epoxy-based resins, fluorine-based resins, polyester-based resins, and polyimide resins. The content of the polymer matrix in the light-controlling layer can be, for example, 30% to 70% by weight, preferably 35% to 65% by weight, and more preferably 40% to 60% by weight.

[0024] Examples of the liquid crystal component include a nematic liquid crystal component, a smectic liquid crystal component, and a cholesteric liquid crystal component. Among these, a nematic liquid crystal component is preferably used. The content of the liquid crystal component in the light-controlling layer may be, for example, 30% to 70% by weight, preferably 35% to 65% by weight, and more preferably 40% to 60% by weight.

[0025] The light-modulating layer may further contain any appropriate material such as a dichroic dye, a dispersant, a crosslinking agent, etc., depending on the purpose.

[0026] The same explanations as for the first transparent conductive film 10, the first transparent substrate 12, and the first transparent electrode layer 14 can be applied to the second transparent conductive film 30, the second transparent substrate 32, and the second transparent electrode layer 34, respectively.

[0027] As shown in FIG. 3 , a cutout portion 50 is provided at the end of the light control film 100, cutting out the light control film 100 from the upper surface 12b of the first transparent substrate 12 to a portion of the second transparent substrate 32 on the light control layer 20 side. A portion including the lower surface of the second transparent substrate 32 remains below the cutout portion 50. A sealing portion 40 is provided in the cutout portion 50 so as to cover the entire end surfaces of the first transparent conductive film 10, the light control layer 20, and the second transparent conductive film 30 exposed by the cutout. Specifically, the sealing portion 40 is provided in close contact with (in other words, in contact with) the entire end surface 10a of the first transparent conductive film 10 (more specifically, the end surface 12a of the first transparent substrate 12 and the end surface 14a of the first transparent electrode layer 14), the end surface 20a of the light control layer 20, and the end surface 30a of the second transparent conductive film 30 (more specifically, the end surface 32a of the second transparent substrate 32 and the end surface 34a of the second transparent electrode layer 34) at the cutout portion 50.

[0028] In the embodiment shown in FIG. 3 , the sealing portion 40 is formed with the same height so that its upper end is flush with the upper surface 12b of the first transparent substrate 12. Furthermore, the sealing portion 40 is formed without any steps so that its end surface 40a is flush with the outer peripheral end surface 32b of the second transparent substrate 32. That is, in the illustrated example, the sealing portion 40 has a shape corresponding to the cutout portion 50. Furthermore, the sealing portion 40 (and the cutout portion 50) is formed to have a constant width in the thickness direction (i.e., the width W1 of the upper end of the sealing portion 40 and the width W2 of the lower end are the same width). The width of the sealing portion is the length in the direction extending outward from the outer peripheral end surface of the light control film, and can be, for example, the length in the direction perpendicular to the direction in which the edge extends in a planar view.

[0029] The notch 50 can be formed so that the length L3 of the end face 30a of the second transparent conductive film 30 in a cut surface along the thickness direction (specifically, a cut surface parallel to the thickness direction and the width direction of the sealing portion) is, for example, 1 μm or more, preferably 3 μm or more. Here, the sealing portion 40 is typically formed in close contact with the end face 30a of the second transparent conductive film 30 from the upper end to the lower end, and therefore the length L3 can correspond to the contact length between the sealing portion 40 and the end face 30a of the second transparent conductive film 30 in the cut surface along the thickness direction.

[0030] Liquid crystal components are present at the end surface 20a of the switchable layer 20, and the liquid crystal components may seep out from the end surface 20a of the switchable layer 20 to the vicinity thereof. This can result in insufficient adhesion between the end surface 20a of the switchable layer 20 and the sealing portion 40 and its vicinity. In contrast, by cutting out a portion of the second transparent substrate 32 rather than the switchable layer 20, the end surface 32a of the second transparent substrate 32, which is less contaminated by liquid crystal components, can be exposed. This provides excellent adhesion between the end surface 32a and the sealing portion 40, improving the adhesion of the sealing portion 40. The contact length L3 (the length of the end surface 30a of the second transparent conductive film 30) between the sealing portion 40 and the end surface 30a of the second transparent conductive film 30 on a cut surface along the thickness direction can be, for example, 5 μm or more or 10 μm or more, and, for example, 50 μm or less or 30 μm or less.

[0031] The ratio of the length L3 to the length L2 of the end face 20a of the switchable layer 20 in a cross section cut along the thickness direction is preferably 0.05 to 10, and may be, for example, 0.1 to 5 or 0.5 to 1. The length L2 may correspond to the contact length between the sealing portion 40 and the end face 20a of the switchable layer 20 in a cross section cut along the thickness direction.

[0032] The contact length (L3 + W2) between the sealing portion 40 and the second transparent conductive film 30 in a cross section cut along the thickness direction is preferably 10 μm or more, and may be, for example, 100 μm to 3000 μm or 500 μm to 2000 μm. The ratio of the contact length (L3 + W2) to the length L2 is preferably 0.5 to 500, and may be, for example, 10 to 300 or 50 to 200. When the contact length between the sealing portion 40 and the second transparent conductive film 30 (substantially, the second transparent substrate 32) is large, the effect of improving the adhesion of the sealing portion 40 can be suitably obtained.

[0033] The contact length L1 between the sealing portion 40 and the end face 10a of the first transparent conductive film 10 in a cut surface along the thickness direction is preferably 10 μm or more, and may be, for example, 20 μm to 200 μm or 30 μm to 100 μm. The ratio of the contact length L1 to the length L2 is preferably 0.5 to 40, and may be, for example, 1 to 30 or 2 to 20.

[0034] The total contact length (L1 + L2 + L3) between the sealing portion 40 and the end face 10a of the first transparent conductive film 10, the end face 20a of the light-controlling layer 20, and the end face 30a of the second transparent conductive film 30 in a cut surface along the thickness direction is preferably 20 μm or more, and may be, for example, 50 μm to 400 μm or 80 μm to 300 μm.

[0035] W1 can be, for example, 100 μm to 3000 μm, preferably 300 μm to 2000 μm or 500 μm to 1500 μm. W2 can be, for example, 0 μm to 3000 μm, preferably 100 μm to 2500 μm, 300 μm to 2000 μm, or 500 μm to 1500 μm. When W2 is 100 μm or more, effects can be obtained such as a favorable contact area between the sealing portion and the second transparent conductive film (more specifically, the second transparent substrate) being secured and the sealing portion being favorably supported by the remainder of the second transparent substrate.

[0036] The configuration of the sealing unit 40 is not limited to the illustrated example. Specifically, the sealing unit 40 does not need to be provided in close contact with the entire length of the end surface 10a of the first transparent conductive film 10, the end surface 20a of the light-controlling layer 20, and the end surface 30a of the second transparent conductive film 30 at the cutout portion 50 in a cross section along the thickness direction. For example, the sealing unit 40 may be provided so as to cover from the middle of the end surface 10a of the first transparent conductive film 10 to the lower end of the end surface 30a of the second transparent conductive film 30 in a cross section along the thickness direction. Specifically, as shown in FIGS. 4A and 4D, the upper end of the sealing unit 40 may be located below the upper surface 12b of the first transparent substrate 12. Alternatively, as shown in FIGS. 4B and 4E, the upper end of the sealing unit 40 may be located above the upper surface 12b of the first transparent substrate 12. When the upper end of the sealing portion 40 is located above the upper surface 12b of the first transparent substrate 12, the sealing portion 40 can be provided extending inward so as to cover part of the upper surface 12b of the first transparent substrate 12. By providing the sealing portion in this manner, the contact area between the sealing portion and the light control film can be increased, which can contribute to improving adhesion.

[0037] Furthermore, for example, the sealing portion 40 does not have to have a constant width in the thickness direction. Specifically, the sealing portion 40 may continuously or stepwise decrease or increase in width downward. For example, in Figures 4C to 4E, the sealing portion 40 continuously decreases in width downward so that W2 = 0. Furthermore, the end surface 40a of the sealing portion 40 may be located inward or outward from the outer peripheral end surface 32b of the second transparent substrate.

[0038] The length of the outer peripheral edge 32b of the second transparent substrate 32 in a cross section cut along the thickness direction can be, for example, 10 μm to 100 μm, preferably 20 μm to 80 μm. When the length of the outer peripheral edge 32b in a cross section cut along the thickness direction is within the above range, the sealing portion can be suitably supported by the remaining part of the second transparent substrate.

[0039] B. Manufacturing Method of Light Control Film The light control film described in Section A can be manufactured by any suitable method. For example, as shown in Figure 5, the manufacturing method of the light control film may include: preparing a light control film 100a having untreated edges, the light control film 10 including, in this order, a first transparent conductive film 10, a light control layer 20 including a polymer matrix and a liquid crystal component, and a second transparent conductive film 30 (Figure 5(a)); removing the first transparent substrate 12, the first transparent electrode layer 14, the light control layer 20, the second transparent electrode layer 34, and the portion of the second transparent substrate 32 on the side of the light control layer 20 from at least a portion of the outer peripheral edge of the light control film 100a so that the underside of the second transparent substrate 32 remains, thereby forming a cutout portion 50 (Figure 5(b)); and applying a sealing resin composition to the cutout portion 50 to form a sealing portion 40 (Figure 5(c)). The first transparent conductive film 10, the light control layer 20, and the second transparent conductive film 30 that constitute the light control film 100a can have substantially the same shape in a plan view.

[0040] When the light control film is a PDLC film, the manufacturing method of the PDLC film may include preparing a first transparent conductive film, a second transparent conductive film, and a coating liquid containing a resin for forming a polymer matrix, a liquid crystal component, and a dispersion medium; applying the coating liquid to the transparent electrode layer surface of one of the transparent conductive films to form a coating layer; drying the coating layer to obtain a PDLC layer in which droplets of the liquid crystal component are dispersed in the polymer matrix; and laminating the other transparent conductive film on the PDLC layer. The coating liquid is preferably an emulsion coating liquid in which liquid crystal particles containing the liquid crystal component are dispersed in a dispersion medium. As the dispersion medium, water or a mixed solvent of water and a water-miscible organic solvent is preferably used.

[0041] In another embodiment, a method for producing a PDLC film may include preparing a first transparent conductive film, a second transparent conductive film, and a coating liquid containing a curable resin for forming a polymer matrix, a liquid crystal component, and a polymerization initiator; applying the coating liquid to the transparent electrode layer surface of one of the transparent conductive films to form a coating layer; laminating the other transparent conductive film on the coating layer to form a laminate; and polymerizing the curable resin to form a polymer matrix, thereby obtaining a PDLC layer by phase separation between the polymer matrix and the liquid crystal component. Alternatively, the coating liquid may be filled between the first transparent conductive film and the second transparent conductive film, which are laminated via a spacer, and then phase separation by polymerization may be carried out.

[0042] The cutout portion can be formed in any appropriate shape depending on the shape of the sealing portion. The cutout portion can be formed, for example, at the end of the light control film 100a by removing predetermined regions of the first transparent substrate 12, the first transparent electrode layer 14, the light control layer 20, the second transparent electrode layer 34, and the second transparent substrate 32 from the top surface of the first transparent substrate 12 downward or diagonally downward. In one embodiment, the cutout portion is formed so that its depth from the top surface of the second transparent conductive film (corresponding to L3' in FIG. 4C ) is, for example, 1 μm or more, 3 μm or more, 5 μm or more, or 10 μm or more, or, for example, 50 μm or less or 30 μm or less.

[0043] The cutout can be formed by any suitable method capable of removing the predetermined region. Specific examples of the cutout include cutting using a milling cutter, an end mill, or the like, laser processing, and etching. Cutting is advantageous in that it has excellent processing efficiency and can provide a suitable surface roughness to the exposed surfaces of the components that are exposed by forming the cutout.

[0044] After the cutout is formed, the processed surface is cleaned as necessary, and then the sealing resin composition is applied to the cutout. When the second transparent substrate is deeply cut out, a large area that is less contaminated by liquid crystal components can be secured, and therefore cleaning can be omitted.

[0045] The encapsulating resin composition may be applied so as to form a coating layer having a shape corresponding to the shape of the encapsulating portion. After application, if necessary, any coating layer protruding above the upper surface of the first transparent conductive film and / or outward from the edge surface of the second transparent substrate may be removed by wiping. The encapsulating resin composition is preferably applied densely so as not to create voids on the coated surface. Examples of encapsulating resins contained in the encapsulating resin composition include epoxy resins, acrylic resins, urethane resins, and silicone resins.

[0046] Typically, the coating layer is dried and / or cured to form the sealing portion. Curing can be carried out, for example, by irradiation with ultraviolet light.

[0047] As shown in Figure 6, the connection between the light control film 100 and the wiring 200A can be achieved by half-cutting the end of the light control film 100 to remove the first transparent conductive film 10 and the light control layer 20, and then connecting the wiring 200A to the exposed surface 34b of the second transparent electrode layer 34 via a conductive material 210. In addition, the connection between the exposed surface 34b of the second transparent electrode layer 34 and the wiring 200A is sealed with a sealing part 60A. Examples of the wiring 200A include a flexible printed circuit board. Examples of the sealing resin that forms the sealing part 60A include the same sealing resin that forms the sealing part 40.

[0048] As shown in Figure 7, the connection between the light-controlling film 100 and the wiring 200B can be achieved by half-cutting the end of the light-controlling film 100 to remove the second transparent conductive film 30 and the light-controlling layer 20, and then connecting the wiring 200B to the exposed surface 14b of the first transparent electrode layer 14 via a conductive material 210. In addition, the connection between the exposed surface 14b of the first transparent electrode layer 14 and the wiring 200B is sealed with a sealing part 60B. Examples of the wiring 200B include a flexible printed circuit board. Examples of the sealing resin that forms the sealing part 60B include the same sealing resin that forms the sealing part 40.

[0049] The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the light control film may have any shape as long as the notch and sealing portion are provided on at least a portion of the outer peripheral edge. Specifically, the light control film may be rectangular or another polygonal shape, and the sealing portion may be provided on at least one edge (edge) of the light control film. In addition, the edge of the light control film may be partially or entirely curved. The light control film may be, for example, triangular, pentagonal, rounded rectangular, circular, elliptical, etc.

[0050] The present invention will be described in detail below using examples, but the present invention is not limited to these examples. The measurement methods for each property are as follows. Unless otherwise specified, "parts" and "%" in the examples and comparative examples are by weight. <Thickness> Measured using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C"). <Volume average particle size of liquid crystal particles in liquid crystal emulsion> 0.1 wt % of liquid crystal emulsion was added to 200 ml of an electrolyte aqueous solution (manufactured by Coulter, "Isoton II"). The resulting mixture was used as a measurement sample. Using a Multisizer 3 (manufactured by Coulter, aperture size = 20 μm), the particle size was divided into 256 equal logarithmic intervals from 0.4 μm to 12 μm, and the volume of each particle size was measured to calculate the volume average particle size. When particles of 12 μm or larger were present, the aperture size was set to 30 μm, and the particle size was divided into 256 equal logarithmic intervals from 0.6 μm to 18 μm, and the volume average particle size was calculated by taking statistics of the volume for each particle size. <Average particle size of resin particles> A measurement sample was prepared by adding several drops of resin dispersion to 100 ml of water. Using a dynamic light scattering particle size distribution analyzer (manufactured by Microtrac, device name "Nanotrac 150"), the measurement sample was placed in the measurement holder of the device, and measurements were performed after confirming on the device monitor that the concentration was measurable.

[0051] (Transparent conductive film) An ITO layer (thickness: approximately 20 nm) was formed by sputtering on one surface of a PET resin substrate (thickness: 50 μm) having a rectangular shape in plan view, to obtain a transparent conductive film having a structure of [transparent substrate / transparent electrode layer].

[0052] (Preparation of emulsion coating liquid) 58.8 parts of a liquid crystal compound (manufactured by JNC Corporation, product name "LX-153XX", birefringence Δn = 0.149 (ne = 1.651, no = 1.502), viscosity = 48.5 mPa s), 40 parts of pure water, and 1.2 parts of a dispersant (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., "Noigen ET159") were mixed and stirred with a homogenizer at 100 rpm for 10 minutes to prepare a liquid crystal emulsion. The average particle size of the liquid crystal particles in the obtained liquid crystal emulsion was 3.5 μm. An emulsion coating liquid was obtained by mixing 31.72 parts of the liquid crystal emulsion, 11.65 parts of an aqueous dispersion of polyether-based polyurethane resin (manufactured by DSM, trade name "NeoRez R967", polymer average particle size: 80 nm, CV value = 0.27, solid content: 40 wt%), 31.09 parts of an aqueous dispersion of acrylic resin (manufactured by DIC, trade name "Burnoc WE-314", polymer average particle size: 140 nm, CV value = 0.25, solid content: 45 wt%), 0.02 parts of a leveling agent (manufactured by DIC, product name "F-444"), 1.35 parts of a crosslinking agent (tris[3-(2-methylaziridin-1-yl)propionic acid]=propylidinetrimethyl), and 24.17 parts of pure water.

[0053] (Formation of PDLC Film) The emulsion coating liquid was applied to the ITO layer surface of the transparent conductive film to form a coating layer. The coating was performed using a wire bar (model number "OSP35"). The coating layer was dried at 25°C for 60 minutes to form a PDLC layer with a thickness of 10 μm. Next, another transparent conductive film was laminated on the PDLC layer. At this time, lamination pressure was applied using a laminator, and the ITO layer of the transparent conductive film was laminated so that it faced the PDLC layer side. This resulted in a PDLC film having a configuration of [first transparent conductive film / PDLC layer / second transparent conductive film].

[0054] (Formation of Cutout Portion) The outer periphery of the PDLC film, excluding one side, was cut using an end mill to form a cutout portion that cuts out obliquely downward from the upper surface of the first transparent substrate of the first transparent conductive film to a portion of the PDLC layer side of the second transparent substrate of the second transparent conductive film.

[0055] (Formation of Sealing Portion) A urethane-based UV-curable resin (NOA65, manufactured by NORLAND) was applied to the edge of the PDLC film, including the notch. The UV-curable resin was applied so as not to create a gap between the light control film surface and the coating layer. The coating layer was cured by UV irradiation, thereby forming a sealing portion.

[0056] In this way, a PDLC film with a sealed portion was obtained. The cross section of the end portion of the obtained PDLC film was observed under a microscope, and the results are shown in FIG.

[0057] As shown in Fig. 8, the entire cutout was filled with the sealing portion. The contact length between the sealing portion and the edge face of the second transparent conductive film on the cross section cut along the thickness direction was 10 µm. The contact length between the sealing portion and the second transparent conductive film on the cross section was 1000 µm.

[0058] The light control film according to the embodiment of the present invention is suitably used for various applications such as advertisements, displays such as guide boards, smart windows, etc.

[0059] REFERENCE SIGNS LIST 10 First transparent conductive film, 12 First transparent substrate, 14 First transparent electrode layer, 20 Light control layer, 30 Second transparent conductive film, 32 Second transparent substrate, 34 Second transparent electrode layer, 40 Sealing portion, 50 Notch portion, 100 Light control film

Claims

1. A light control film comprising, in this order, a first transparent conductive film, a light control layer comprising a polymer matrix and a liquid crystal component, and a second transparent conductive film, wherein the first transparent conductive film comprises a first transparent substrate and a first transparent electrode layer arranged on the light control layer side of the first transparent substrate, the second transparent conductive film comprises a second transparent substrate and a second transparent electrode layer arranged on the light control layer side of the second transparent substrate, at least a part of the outer peripheral edge of the light control film is provided with a cutout portion that extends from the first transparent substrate to a part of the second transparent substrate on the light control layer side, and a sealing portion is provided that covers the edge faces of the light control layer and the second transparent conductive film in the cutout portion.

2. The light control film according to claim 1, wherein the length of the edge of the second transparent conductive film at the notch is 1 μm or more in a cross section cut along the thickness direction.

3. The light control film according to claim 1, wherein the contact length between the sealing portion and the second transparent conductive film is 100 μm or more on a cross section cut along the thickness direction.

4. The light control film according to claim 1, which has a polygonal shape and has the sealing portion provided on at least one edge.

5. The light control film according to claim 1, which has a rectangular shape and has the sealing portion provided on three edges excluding the edge to which the wiring is connected.

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