Light control laminate, light control plate, and method for manufacturing light control plate

Abstract

To provide a light control laminate which can enhance a degree of freedom related to viscoelasticity of an optical transparent adhesive layer, a light control plate, and a method for manufacturing a light control plate.SOLUTION: A light control laminate, which includes a first transparent film having a first transparent electrode layer 35, a second transparent film having a second transparent electrode layer 34, and a light control layer 31 which has a plurality of gaps partitioned by an ionizing radiation curable resin layer filled with a liquid crystal composition, and is arranged between the first transparent electrode layer 35 and the second transparent electrode layer 34, is stuck to the curved surface of a transparent base material 62 by a first optical transparent adhesive layer 61, and changes the haze of the light control layer 31 by change of a voltage applied between the first transparent electrode layer 35 and the second transparent electrode layer 34, includes a transparent heat-shrinkable film 42 which is arranged on a side opposite to the side of the light control layer 31 to the first transparent film and is stuck to the first transparent film.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a light control laminate in which a liquid crystal composition is filled into a plurality of voids defined by an ionizing radiation curable resin layer, a light control panel including the light control laminate, and a method for manufacturing the light control panel. [Background technology]

[0002] The light-control sheet comprises a light-control layer between two transparent electrode films. The light-control layer comprises an ionizing radiation curable resin layer that defines multiple voids, and a liquid crystal composition that fills the voids. Changing the voltage between the transparent electrode films changes the alignment state of the liquid crystal compound. Changing the alignment state of the liquid crystal compound changes the degree of scattering at the interface between the ionizing radiation curable resin layer and the liquid crystal composition, thereby changing the transparency of the light-control sheet.

[0003] When a light-controlling sheet is attached to a curved surface such as a vehicle windshield or a show window using an optical transparent adhesive layer, distortions such as wrinkles and folds may occur in the light-controlling sheet. One example of a technique for suppressing distortion in the light-controlling sheet is to set the thickness, storage modulus, and loss tangent of the optical transparent adhesive layer within predetermined ranges (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-084621 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, when attaching a light-adjusting sheet to a curved surface, having the storage modulus and loss tangent of the optical transparent adhesive layer within a predetermined range improves the conformability of the optical transparent adhesive layer to the curved surface, thereby improving the conformability of the light-adjusting sheet to the curved surface. On the other hand, limiting the storage modulus and loss tangent of the optical transparent adhesive layer to a predetermined range makes it difficult to peel the light-adjusting sheet attached to a curved surface from the curved surface and reattach it to the curved surface. Furthermore, reducing the radius of curvature on a curved surface expands the application range of light-adjusting sheets and promotes the development of the light-adjusting sheet industry, but forces the optical transparent adhesive layer to have a storage modulus and loss tangent outside the predetermined range. Thus, light-adjusting panels with a light-adjusting sheet attached to the curved surface of a transparent substrate still have room for improvement in terms of increasing the degree of freedom regarding the viscoelasticity of the optical transparent adhesive layer. [Means for solving the problem]

[0006] A light control laminate that solves the above problems includes a first transparent film having a first transparent electrode layer, a second transparent film having a second transparent electrode layer, an ionizing radiation curable resin layer that defines a plurality of voids, and a light control layer that includes a liquid crystal composition filled in the voids and is disposed between the first transparent electrode layer and the second transparent electrode layer. The light control laminate is attached to a curved surface of a transparent substrate by an optical transparent adhesive layer, and changes the haze of the light control layer by changing the voltage applied between the first transparent electrode layer and the second transparent electrode layer. The light control laminate includes a transparent heat-shrinkable film that is disposed on the opposite side of the first transparent film from the light control layer and is attached to the first transparent film.

[0007] A dimming board for solving the above problem comprises a dimming laminate, a transparent substrate having a curved surface, and an optically transparent adhesive layer arranged between the curved surface and the dimming laminate to attach the dimming laminate to the curved surface, wherein the dimming laminate comprises a first transparent film having a first transparent electrode layer, a second transparent film having a second transparent electrode layer, and a dimming layer arranged between the first transparent electrode layer and the second transparent electrode layer, the dimming layer having a liquid crystal composition filled in multiple gaps defined by an ionizing radiation cured resin layer, and the dimming plate further comprises a transparent heat-shrinkable film configured to change the haze of the dimming layer by changing the voltage applied between the first transparent electrode layer and the second transparent electrode layer, and which bends the dimming laminate to conform to the curved surface when heated, the transparent heat-shrinkable film being arranged on the opposite side of the first transparent film from the dimming layer and attached to the first transparent film.

[0008] A method for manufacturing a dimming plate that solves the above problem is a method for manufacturing a dimming plate that manufactures a dimming plate by attaching a dimming laminate to a curved surface of a transparent substrate using an optical transparent adhesive layer, wherein the dimming laminate comprises a first transparent electrode layer, a second transparent electrode layer, a dimming layer that is disposed between the first transparent electrode layer and the second transparent electrode layer and has a liquid crystal composition filled in multiple gaps defined by an ionizing radiation cured resin layer, and a transparent heat shrinkable film that bends the ionizing radiation cured resin layer to conform to the curved surface when heated at a first heat shrinkage temperature, and is configured to change the haze of the dimming layer by changing the voltage applied between the first transparent electrode layer and the second transparent electrode layer, and includes heating the dimming laminate to a thermal processing temperature that is equal to or higher than the first heat shrinkage temperature.

[0009] According to each of the above configurations, the shrinkage of the transparent heat-shrinkable film deforms the light-controlling laminate into a convex curved surface, protruding from the transparent heat-shrinkable film toward the second transparent electrode layer. When the transparent heat-shrinkable film of the light-controlling laminate is attached to a concave surface that is recessed from the transparent heat-shrinkable film toward the second transparent electrode layer, the light-controlling laminate itself has a convex curved surface conforming to the curved surface. As a result, the light-controlling laminate itself has a shape conforming to the curved surface of the transparent substrate, thereby increasing the degree of freedom regarding the viscoelasticity of the optical transparent adhesive layer.

[0010] In the light-control laminate, the transparent heat-shrinkable film may be attached to the entire first transparent film. According to this configuration, contraction of the transparent heat-shrinkable film deforms the entire light-switching stack into a convex curved surface so that the transparent heat-shrinkable film protrudes in a direction from the transparent heat-shrinkable film toward the second transparent electrode layer. When a curved surface having a size corresponding to the size of the first transparent film is positioned so as to be recessed in a direction from the transparent heat-shrinkable film toward the second transparent electrode layer, the entire light-switching stack has a convex curved surface conforming to the curved surface of the transparent substrate. This makes it easy to attach the light-switching stack to the curved surface of the transparent substrate across the entire first transparent film.

[0011] In the above-mentioned photochromic stack, when viewed from a viewpoint opposite the surface of the photochromic stack, the transparent heat-shrinkable film may be smaller than the first transparent film, and the entire transparent heat-shrinkable film may be attached to a portion of the first transparent film.

[0012] According to this configuration, contraction of the transparent heat-shrinkable film deforms a portion of the light-switching stack into a convex curved surface so that the portion protrudes from the transparent heat-shrinkable film toward the second transparent electrode layer. When a curved surface having a size corresponding to a portion of the first transparent film is positioned so as to be recessed from the transparent heat-shrinkable film toward the second transparent electrode layer, the portion of the light-switching stack has a convex curved surface conforming to the curved surface of the transparent substrate. This makes it easy to attach the light-switching stack to a curved surface having a size corresponding to a portion of the first transparent film.

[0013] The light-controlling laminate may include a plurality of the transparent heat-shrinkable films. According to this configuration, the shrinkage of each transparent heat-shrinkable film deforms the portion of the light-controlling laminate to which the transparent heat-shrinkable film is attached into a convex curved surface so that the transparent heat-shrinkable film protrudes from the transparent heat-shrinkable film toward the second transparent electrode layer. When each curved surface, having a size corresponding to each transparent heat-shrinkable film, is arranged so that it protrudes from the transparent heat-shrinkable film toward the second transparent electrode layer, the light-controlling laminate has a shape that conforms to the curved surface of the transparent substrate. This makes it easy to attach the light-controlling laminate to the curved surface of the transparent substrate.

[0014] In the above-mentioned light-controlling laminate, the main shrinkage direction of the transparent heat-shrinkable film may intersect with the longitudinal direction of the light-controlling laminate. In the above-mentioned configurations, the main shrinkage direction of the transparent heat-shrinkable film may be perpendicular to the longitudinal direction of the light-controlling laminate. Each of these configurations also makes it easy to bend the light-controlling laminate in a direction in which the light-controlling laminate is more difficult to bend than the longitudinal direction.

[0015] In the above-mentioned light-controlling laminate, the heat shrinkage temperature of the transparent heat shrinkable film may be lower than the heat shrinkage temperatures of a first transparent support layer that supports the first transparent electrode layer in the first transparent film, a second transparent support layer that supports the second transparent electrode layer in the second transparent film, and the ionizing radiation cured resin layer.

[0016] According to this configuration, when the transparent heat-shrinkable film is thermally shrunk, it is possible to deform the transparent heat-shrinkable film so as to suppress thermal deformation of the transparent support layers and the ionizing radiation cured resin layer. In the above-mentioned light control plate, the transparent heat shrinkable film may be arranged on the opposite side of the light control layer from the optical transparent adhesive layer, and the curved surface may be a concave curved surface.

[0017] In the above-mentioned light control plate, the transparent heat shrinkable film may be disposed between the light control layer and the optical transparent adhesive layer, and the curved surface may be a convex curved surface. In the light control panel, the radius of curvature of the curved surface may have a minimum value in the main shrinkage direction of the transparent heat-shrinkable film when viewed from a viewpoint opposite the surface of the light control laminate. This configuration aligns the direction of the smallest radius of curvature in the curved shape of the light control laminate that it originally has with the direction of the smallest radius of curvature in the curved surface of the transparent substrate. This makes it easier for the light control laminate to follow parts of the curved surface of the transparent substrate that are difficult for a flat sheet to follow, making it easier to attach the light control laminate to the curved surface of the transparent substrate.

[0018] In the method for manufacturing a light control panel, the thermal processing temperature may be lower than the heat shrinkage temperatures of a first transparent support layer that supports the first transparent electrode layer, a second transparent support layer that supports the second transparent electrode layer, and the ionizing radiation curable resin layer. This configuration suppresses deformation due to heating of each transparent support layer and the ionizing radiation curable resin layer. [Effects of the Invention]

[0019] The light control laminate and light control plate of the present disclosure increase the degree of freedom regarding the viscoelasticity of the optical transparent adhesive layer. [Brief explanation of the drawings]

[0020] [Figure 1] Figure 1 is a diagram showing the structure of a dimming panel. [Figure 2] FIG. 2 is an enlarged cross-sectional view of the light control panel. [Figure 3] FIG. 3 is an enlarged cross-sectional view of the light-control sheet. [Figure 4] FIG. 4 is a flowchart showing a method for manufacturing a light control panel. [Figure 5] FIG. 5 is a process diagram showing a process for forming a light control laminate. [Figure 6] FIG. 6 is a structural diagram of a dimming panel showing a modified example of the dimming panel. DETAILED DESCRIPTION OF THE INVENTION

[0021] [Light control panel 10] As shown in Fig. 1, the dimming plate 10 has a curved plate shape. The dimming plate 10 has a first surface 50A which is a curved surface, and a second surface 60A which is the side surface opposite to the first surface 50A. The dimming plate 10 has a dimming laminate 11 and a base laminate 60. The first surface 50A is the front surface of the dimming laminate 11. The second surface 60A is the back surface of the base laminate 60.

[0022] As shown in FIG. 2, the light control laminate 11 includes a light control sheet and a heat-shrinkable sheet 40. The light-controlling sheet includes a light-controlling layer 31, a first alignment layer 33, a second alignment layer 32, a first transparent electrode layer 35, a second transparent electrode layer 34, a first transparent support layer 37, and a second transparent support layer 36. The first alignment layer 33, the first transparent electrode layer 35, and the first transparent support layer 37 constitute a first transparent film. The second alignment layer 32, the second transparent electrode layer 34, and the second transparent support layer 36 constitute a second transparent film. The light-controlling sheet has the following layers arranged in the direction from the light-controlling laminate 11 toward the base laminate 60: the first transparent support layer 37, the first transparent electrode layer 35, the first alignment layer 33, the light-controlling layer 31, the second alignment layer 32, the second transparent electrode layer 34, and the second transparent support layer 36.

[0023] The heat-shrinkable sheet 40 includes a second optically transparent adhesive layer 41 and a transparent heat-shrinkable film 42. The heat-shrinkable sheet 40 has the transparent heat-shrinkable film 42 and the second optically transparent adhesive layer 41 arranged in this order in the direction from the light-control laminate 11 toward the base laminate 60.

[0024] The substrate laminate 60 includes a first optical transparent adhesive layer 61 and a transparent substrate 62. In the substrate laminate 60, the first optical transparent adhesive layer 61 and the transparent substrate 62 are arranged in this order in the direction from the light control laminate 11 toward the substrate laminate 60.

[0025] The surface of the light-controlling laminate 11 is the surface of the transparent heat-shrinkable film 42. The back surface of the light-controlling laminate 11 is the back surface 36A of the second transparent support layer 36. The surface of the light-controlling sheet is the surface 37A of the first transparent support layer 37. The back surface of the light-controlling sheet is the back surface 36A of the second transparent support layer 36. The surface of the base laminate 60 is the surface of the first optical transparent adhesive layer 61. The back surface of the base laminate 60 is the back surface of the transparent base material 62.

[0026] Returning to FIG. 1 , the first surface 50A is a concave curved surface recessed in a direction from the dimming laminate 11 toward the base laminate 60. The first direction D1 is perpendicular to the thickness direction of the dimming panel 10 and the second direction D2. The second direction D2 is perpendicular to the thickness direction of the dimming panel 10. In a cross section including the thickness direction of the dimming panel 10 and the first direction D1, the first surface 50A has a concave curved shape recessed in a direction from the dimming laminate 11 toward the base laminate 60. In a cross section including the thickness direction of the dimming panel 10 and the second direction D2, the first surface 50A has a linear shape extending in the second direction D2. The first surface 50A is, for example, a part of a cylindrical surface having an axis extending in the second direction D2.

[0027] The second surface 60A may be a curved surface or a flat surface. The second surface 60A may be parallel to the first surface 50A or may not be parallel to the first surface 50A. The second surface 60A is, for example, a convex curved surface that protrudes from the dimming laminate 11 in a direction toward the base laminate 60. The second surface 60A has a convex curved shape that protrudes from the dimming laminate 11 in a direction toward the base laminate 60 in a cross section including the thickness direction of the dimming panel 10 and the first direction D1. The second surface 60A has a linear shape extending in the second direction D2 in a cross section including the thickness direction of the dimming panel 10 and the second direction D2. The second surface 60A is, for example, a part of a cylindrical surface having an axis extending in the second direction D2.

[0028] The light control panel 10 may be used as a partition panel that divides a space, or as a screen that displays an image. The partition panel may be window glass or a room divider. The window glass may be mounted on a moving object such as a vehicle or an aircraft, or may be installed in a building such as an office building or a public facility. The room divider may be placed inside a vehicle or an indoor space. The screen may be a front screen that uses reflected light for the image, or a rear screen that uses transmitted light for the image.

[0029] [Base material laminate 60] As shown in FIG. 2 , the transparent substrate 62 has a curved surface that conforms to the first surface 50A of the dimming panel 10. The surface of the transparent substrate 62 is a concave curved surface that recesses from the transparent heat-shrinkable film 42 toward the second transparent electrode layer 34. In a cross section including the thickness direction of the dimming panel 10 and the first direction D1, the surface of the transparent substrate 62 has a concave curved shape that recesses from the transparent heat-shrinkable film 42 toward the second transparent electrode layer 34. In a cross section including the second direction D2 and the thickness direction of the dimming panel 10, the surface of the transparent substrate 62 has a linear shape extending in the second direction D2. The surface of the transparent substrate 62 is, for example, a part of a cylindrical surface having an axis extending in the second direction D2. The radius of curvature of the surface of the transparent substrate 62 may be 1000 mm or less, or may be 100 mm or less. The surface of the transparent substrate 62 is attached to the entire back surface 36A of the second transparent support layer 36 by a first optical transparent adhesive layer 61.

[0030] The transparent substrate 62 has a back surface which is the second surface 60A of the light control panel 10. The transparent substrate 62 may have a convex curved plate shape in which the second surface 60A protrudes in the direction from the light control stack 11 toward the substrate stack 60.

[0031] The transparent substrate 62 has heat resistance such that it does not deform when heated for bonding the light control laminate 11 or the substrate laminate 60. The material constituting the transparent substrate 62 may be a transparent resin such as an acrylic resin, a polycarbonate resin, or a polymethyl methacrylate resin, or may be glass such as alkali glass or alkali-free glass. The transparent substrate 62 may have a curved plate shape in which the second surface 60A protrudes in the direction from the light control laminate 11 toward the substrate laminate 60, or may have a curved plate shape in which the surface is recessed in the direction from the light control laminate 11 toward the substrate laminate 60. The cross-sectional structure of the transparent substrate 62 may be a single-layer structure or a multi-layer structure.

[0032] The color of the transparent substrate 62 may be an achromatic color or a chromatic color. The color of the transparent substrate 62 may be the same as the chromatic color of the light controlling sheet, or may be different from the chromatic color of the light controlling sheet.

[0033] The transparent substrate 62 has higher rigidity than the light control laminate 11. The transparent substrate 62 does not have flexibility. The light control laminate 11 has flexibility to bend in accordance with the curved surface of the substrate laminate 60. The dimming plate 10 may have one dimming laminate 11 attached to the surface of one base laminate 60, or may have multiple dimming laminates 11 attached to the surface of one base laminate 60, or may have a stack of multiple dimming laminates 11 attached to the surface of one base laminate 60. The dimming plate 10 may sandwich the dimming laminate 11 between a base laminate 60 to which one or more dimming laminates 11 have been attached and another base laminate 60. The dimming plate 10 may sandwich the dimming laminate 11 between a base laminate 60 to which a stack of multiple dimming laminates 11 have been attached and another base laminate 60.

[0034] [Light-controlling laminate 40] The opacity of a light-controlling sheet is achieved by scattering transmitted light through the light-controlling sheet. An opaque light-controlling sheet has a lower parallel light transmittance than a transparent light-controlling sheet. An opaque light-controlling sheet has a higher haze than a transparent light-controlling sheet. The color of an opaque light-controlling sheet may be achromatic or chromatic. The color of a transparent light-controlling sheet may be achromatic or chromatic.

[0035] The drive type of the light-controlling sheet may be a reverse type. The drive unit 12 supplies a voltage signal to the reverse type light-controlling sheet. The reverse type light-controlling sheet changes from transparent to opaque in response to the input of a voltage signal. The reverse type light-controlling sheet remains opaque while the voltage signal is input. The reverse type light-controlling sheet returns from opaque to transparent in response to the cessation of the supply of the voltage signal.

[0036] The drive type of the light-controlling sheet may be a normal type. The drive unit 12 supplies a voltage signal to the normal type light-controlling sheet. The normal type light-controlling sheet changes from opaque to transparent in response to the input of the voltage signal. The normal type light-controlling sheet remains transparent while the voltage signal is input. The normal type light-controlling sheet returns from transparent to opaque in response to the cessation of the supply of the voltage signal.

[0037] The following mainly describes the configuration of the reverse-type light controlling sheet. The configuration of the normal-type light controlling sheet that differs from the reverse-type light controlling sheet is described, and the configuration of the normal-type light controlling sheet that overlaps with the reverse-type light controlling sheet is omitted.

[0038] The light-controlling layer 31 is located between the first alignment layer 33 and the second alignment layer 32. A surface 31S of the light-controlling layer 31 contacts the first alignment layer 33. A back surface 31F of the light-controlling layer 31 contacts the second alignment layer 32. The first alignment layer 33 is located between the light-controlling layer 31 and the first transparent electrode layer 35 and contacts both the light-controlling layer 31 and the first transparent electrode layer 35. The second alignment layer 32 is located between the light-controlling layer 31 and the second transparent electrode layer 34 and contacts both the light-controlling layer 31 and the second transparent electrode layer 34.

[0039] The first transparent electrode layer 35 is connected to the driving unit 12 through the first connection terminal 22B and the first wiring 23B. The first transparent electrode layer 35 is located between the first alignment layer 33 and the first transparent support layer 37, and is in contact with the first alignment layer 33 and the first transparent support layer 37.

[0040] The second transparent electrode layer 34 is connected to the driving unit 12 through the second connection terminal 22A and the second wiring 23A. The second transparent electrode layer 34 is located between the second alignment layer 32 and the second transparent support layer 36, and is in contact with the second alignment layer 32 and the second transparent support layer 36.

[0041] The first transparent electrode layer 35 and the second transparent electrode layer 34 are visually recognized as colorless and transparent or colored and transparent, respectively. The materials constituting the first transparent electrode layer 35 and the second transparent electrode layer 34 are conductive inorganic oxides, metals, or conductive organic polymer compounds, respectively. An example of the thickness of the first transparent electrode layer 35 and the second transparent electrode layer 34 is 5 nm or more and 200 nm or less, respectively.

[0042] The first transparent support layer 37 and the second transparent support layer 36 are visually recognized as colorless and transparent or colored and transparent, respectively. The materials constituting the first transparent support layer 37 and the second transparent support layer 36 are organic polymer compounds or inorganic polymer compounds, respectively. An example of the thickness of the first transparent support layer 37 and the second transparent support layer 36 is 20 μm or more and 400 μm or less. The back surface 36A of the second transparent support layer 36 is a convex curved surface that protrudes from the transparent heat-shrinkable film 42 in a direction toward the second transparent electrode layer 34.

[0043] The light-controlling sheet may include another functional layer between the first transparent electrode layer 35 and the first transparent support layer 37. The light-controlling sheet may include another functional layer between the second transparent electrode layer 34 and the second transparent support layer 36. The other functional layer may be a gas barrier layer that prevents oxygen and moisture from passing through toward the light-controlling layer 31, or an ultraviolet barrier layer that prevents ultraviolet light of a specific wavelength from passing through toward the light-controlling layer 31. The other functional layer may be a hard coat layer that mechanically protects the light-controlling sheet, or an adhesive layer that improves adhesion between layers in the light-controlling sheet.

[0044] [Transparent Heat Shrink Film 42] In the light control panel 10, the transparent heat shrinkable film 42 is disposed on the opposite side of the first optical transparent adhesive layer 61 with respect to the light control layer 31. The transparent heat shrinkable film 42 is a resin film such as a polyolefin resin film, a polyvinyl chloride resin film, a polyester resin film, or a polystyrene resin film.

[0045] The surface of the transparent heat-shrinkable film 42 is a concave curved surface recessed in a direction from the transparent heat-shrinkable film 42 toward the second transparent electrode layer 34. The transparent heat-shrinkable film 42 has a back surface that is a curved surface along the first surface 50A of the light control panel 10. The back surface of the transparent heat-shrinkable film 42 is a convex curved surface protruding from the transparent heat-shrinkable film 42 toward the second transparent electrode layer 34. The back surface of the transparent heat-shrinkable film 42 is attached to the entire first transparent support layer 37 by a second optical transparent adhesive layer 41.

[0046] The transparent heat-shrinkable film 42 shrinks when heated. The first heat-shrinkable temperature, which is the temperature at which the transparent heat-shrinkable film 42 begins to shrink, is 50°C or higher, and may be 80°C or higher, or 150°C or higher. The first heat-shrinkable temperature is the temperature at which the polymer transitions from a glassy state to a rubbery state. The main shrinkage direction having the largest heat shrinkage amount in the transparent heat-shrinkable film 42 may be one direction that intersects with the first direction D1, or may be the second direction D2. The main shrinkage direction of the transparent heat-shrinkable film 42 may be two directions, the first direction D1 and the second direction D2. When the main shrinkage direction of the transparent heat-shrinkable film 42 is two directions, the longitudinal direction of the transparent heat-shrinkable film 42 is preferably the first direction D1, which intersects with the second direction D2, from the viewpoint of conforming the shape of the light-control laminate 11 to the surface of the transparent substrate 62. From the viewpoint of bending the light-control sheet by thermal shrinkage of the transparent heat-shrinkable film 42, the length in the longitudinal direction of the transparent heat-shrinkable film 42 is preferably at least 5 times the length in the lateral direction of the transparent heat-shrinkable film 42, and more preferably at least 10 times.

[0047] The transparent heat-shrinkable film 42 may be a uniaxially stretched resin film stretched in a direction intersecting the first direction D1. The transparent heat-shrinkable film 42 may be a uniaxially stretched resin film stretched in the second direction D2, or a resin film whose tensile breaking strength in the second direction D2 is higher than the tensile breaking strength in any direction other than the second direction D2. The transparent heat-shrinkable film 42 may have its longitudinal direction in the first direction D1 or the second direction D2. The transparent heat-shrinkable film 42 may be a biaxially stretched resin film stretched in two axes including the second direction D2, and may be a resin film whose longitudinal direction is in the second direction D2. The radius of curvature on the surface of the transparent heat-shrinkable film 42 has its smallest value in the main shrinkage direction of the transparent heat-shrinkable film 42.

[0048] Each optically transparent adhesive layer 41, 61 may be a double-sided tape material made of an optical adhesive without a core material, or may be a cured product of an optical adhesive having independent photocurability. The adhesive strength of each optically transparent adhesive layer 41, 61 to glass is 10 N / 25 mm or more. The adhesive strength of each optically transparent adhesive layer 41, 61 to glass is preferably 20 N / 25 mm or more, more preferably 25 N / 25 mm or more, and even more preferably 30 N / 25 mm or more. The total light transmittance of each optically transparent adhesive layer 41, 61 is preferably 90% or more, more preferably 95% or more, from the viewpoint of enhancing the transparency of the light control panel 10. The haze of each optically transparent adhesive layer 41, 61 is preferably 1% or less, more preferably 0.5% or less, from the viewpoint of enhancing the transparency of the light control panel 10. The thickness of each optically transparent adhesive layer 41, 61 may be 5 μm or more and 300 μm or less.

[0049] The material constituting each of the optically transparent adhesive layers 41, 61 is an optically transparent adhesive. The optically transparent adhesive may be an ultraviolet curable resin, an ultraviolet blocking resin, or a thermosetting resin. The optically transparent adhesive may be at least one selected from the group consisting of an acrylic adhesive, a urethane adhesive, and a silicone adhesive.

[0050] The driver 12 is separately connected to the first transparent electrode layer 35 and the second transparent electrode layer 34. The driver 12 applies a voltage between the first transparent electrode layer 35 and the second transparent electrode layer 34 by supplying a voltage signal. The driver 12 changes the voltage between the first transparent electrode layer 35 and the second transparent electrode layer 34 by stopping the supply of the voltage signal. Supplying and stopping the supply of the voltage signal changes the alignment state of the liquid crystal compound LCM. The driver 12 reversibly switches the light-control stack 11 from transparent to opaque by changing the alignment state of the liquid crystal compound LCM.

[0051] When the driving unit 12 stops supplying a voltage signal, the alignment state of the liquid crystal compound LCM follows the alignment restriction force of the first alignment layer 33 and the second alignment layer 32. The alignment state of the liquid crystal compound LCM following the alignment restriction force allows visible light to transmit through the light control layer 31. This makes the light control stack 11 transparent. When the driving unit 12 is supplying a voltage signal, 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 following the action force of the electric field causes the light control layer 31 to scatter visible light. This makes the light control stack 11 opaque.

[0052] [Photochromic layer 31] As shown in FIG. 3, the light-controlling layer 31 includes a liquid crystal composition 31LC, spacers SP, and an ionizing radiation curable resin layer 31P.

[0053] The liquid crystal composition 31LC includes a liquid crystal compound LCM. The liquid crystal composition 31LC may contain additives such as a dichroic dye DP, an antifoaming agent, an antioxidant, a weathering agent, and a solvent. The dichroic dye DP is driven by a guest-host mechanism using the liquid crystal compound LCM as a host to exhibit color.

[0054] The spacers SP are dispersed throughout the ionizing radiation cured resin layer 31P. The particle size of the spacers SP determines the thickness of the photochromic layer 31. An example of the thickness of the photochromic layer 31 is 5 μm or more and 100 μm or less. The spacers SP may be bead spacers or photospacers formed by exposing and developing a photoresist.

[0055] The ionizing radiation curable resin layer 31P is a cured product of an ionizing radiation curable composition. The ionizing radiation may be ultraviolet light or electron beams. The ionizing radiation curable composition may be an ultraviolet light curable composition or an electron beam curable composition. The ionizing radiation curable resin layer 31P defines voids 31D in the light control layer 31. The voids 31D are filled with a liquid crystal composition 31LC. The voids 31D may be isolated from other voids 31D adjacent to the void 31D, or may be connected to other adjacent voids 31D. The voids 31D may be unevenly distributed in the ionizing radiation curable resin layer 31P, or may be uniformly dispersed in the ionizing radiation curable resin layer 31P.

[0056] The type of retention of the liquid crystal composition 31LC by the ionizing radiation curable resin layer 31P is any one selected from the group consisting of a polymer dispersion type, a polymer network type, and an encapsulation type. The polymer dispersion type light control layer 31 includes an ionizing radiation curable resin layer 31P that defines a large number of isolated voids 31D. The polymer dispersion type light control layer 31 retains the liquid crystal composition 31LC in the voids 31D dispersed in the ionizing radiation curable resin layer 31P. The voids 31D are formed by phase separation between the cured product of the ionizing radiation curable composition and the liquid crystal composition 31LC.

[0057] The polymer network type light control layer 31 has three-dimensional network-like voids 31D in the ionizing radiation curable resin layer 31P. The polymer network type light control layer 31 holds a liquid crystal composition 31LC in the interconnected network-like voids 31D. The capsule type light control layer 31 holds a liquid crystal composition 31LC in capsule-like voids 31D dispersed in the ionizing radiation curable resin layer 31P.

[0058] The ionizing radiation curable resin layer 31P is formed by applying a photochromic coating liquid containing an ionizing radiation curable composition and a liquid crystal composition 31LC, and then irradiating the coating layer with ionizing radiation. The photochromic coating liquid contains a polymerization initiator for initiating polymerization of the ionizing radiation curable composition. The ionizing radiation curable resin layer 31P contains the polymerization initiator that initiated the polymerization.

[0059] The heat shrinkage temperature, at which the transparent substrate 62 begins to shrink, is sufficiently higher than the first heat shrinkage temperature. The second heat shrinkage temperature is the lowest heat shrinkage temperature among the temperatures at which the ionizing radiation curable resin layer 31P, the alignment layers 32 and 33, and the transparent support layers 36 and 37 begin to shrink. The second heat shrinkage temperature is the temperature at which the polymer transitions from a glassy state to a rubbery state. The second heat shrinkage temperature is preferably at least 10°C higher than the first heat shrinkage temperature, and more preferably at least 20°C higher.

[0060] [Manufacturing method] As shown in FIG. 4, the method for manufacturing the light control panel 10 includes forming a light control sheet (step S11), forming a light control laminate 11 (step S12), attaching (step S13), and heating (step S14).

[0061] When the light-controlling sheet includes a first alignment layer 33 and a second alignment layer 32, forming the light-controlling sheet includes forming the first alignment layer 33 on a first transparent electrode layer 35 and forming the second alignment layer 32 on a second transparent electrode layer 34. Forming the light-controlling sheet includes forming a light-controlling coating layer containing an ionizing radiation-curable composition and a liquid crystal composition 31LC between the first alignment layer 33 and the second alignment layer 32. The light-controlling coating layer is formed by applying a light-controlling coating solution to the first alignment layer 33 supported on a first transparent support layer 37. The light-controlling coating layer is sandwiched between the first alignment layer 33 supported on the first transparent support layer 37 and the second alignment layer 32 supported on a second transparent support layer 36.

[0062] When the light-controlling sheet does not include the first alignment layer 33 and the second alignment layer 32, the light-controlling coating layer is formed by applying a light-controlling coating liquid to a first transparent electrode layer 35 supported on a first transparent support layer 37. The light-controlling coating layer is sandwiched between the first transparent electrode layer 35 supported on the first transparent support layer 37 and the second transparent electrode layer 34 supported on the second transparent support layer 36.

[0063] Formation of the light-controlling sheet involves irradiating the light-controlling coating layer with ionizing rays to form a light-controlling layer 31 between a first transparent electrode layer 35 and a second transparent electrode layer 34. The light-controlling coating layer may be irradiated with ionizing rays from the first transparent support layer 37 toward the light-controlling coating layer, from the second transparent support layer 36 toward the light-controlling coating layer, or a combination of these. The ionizing rays irradiated with ionizing rays initiate polymerization and phase-separate liquid crystal particles of the liquid crystal composition 31LC from the polymer.

[0064] 5, forming the light control laminate 11 (step S12) includes attaching a transparent heat-shrinkable film 42 to the surface 37A of the first transparent support layer 37 of the light control sheet via a second optically transparent adhesive layer 41. The light control sheet and the transparent heat-shrinkable film 42 each have a planar shape. The second optically transparent adhesive layer 41 may be attached to the surface 37A of the first transparent support layer 37 and then attached to the transparent heat-shrinkable film 42, or may be attached to the transparent heat-shrinkable film 42 and then attached to the surface 37A of the first transparent support layer 37.

[0065] The attachment (step S13) includes attaching the curved surface of the transparent substrate 62 to the back surface 36A of the second transparent support layer 36 in the light control laminate 11 via the first optical transparent adhesive layer 61. The first optical transparent adhesive layer 61 may be attached to the back surface 36A of the second transparent support layer 36 and then attached to the surface of the transparent substrate 62, or may be attached to the back surface 36A of the second transparent support layer 36 after being attached to the surface of the transparent substrate 62.

[0066] Heating (step S14) includes heating the adhesive body in which the light control laminate 11 is attached to the base laminate 60. The thermal processing temperature at which the adhesive body is heated is higher than the first thermal shrinkage temperature of the transparent heat shrinkable film 42. The thermal processing temperature of the adhesive body is preferably 10°C or more higher than the first thermal shrinkage temperature of the transparent heat shrinkable film 42. The thermal processing temperature of the adhesive body is lower than the second thermal shrinkage temperature, and preferably 10°C or more lower than the second thermal shrinkage temperature.

[0067] The thermal processing temperature of the adhesive body is appropriately selected so that the curvature of the transparent heat-shrinkable film 42 at the heating temperature matches the curvature of the surface of the transparent substrate 62. The shrinkage rate in the main shrinkage direction of the transparent heat-shrinkable film 42 at the thermal processing temperature may be 5% or more and 10% or less, 10% or more and 20% or less, or 20% or more.

[0068] The thermal processing temperature of the adhesive body may be appropriately selected depending on the haze of the opaque light-control sheet and the haze of the transparent heat-shrinkable film 42 so as to satisfy the haze required for the opaque light-control board 10. The thermal processing temperature of the adhesive body may be appropriately selected depending on the haze of the transparent light-control sheet and the haze of the transparent heat-shrinkable film 42 so as to satisfy the haze required for the transparent light-control board 10. The haze of the transparent heat-shrinkable film 42 after heating may be 10% or less, or may be 5% or less.

[0069] The amount of heat shrinkage at the heat processing temperature of each of the ionizing radiation cured resin layer 31P, the alignment layers 32, 33, and the transparent support layers 36, 37 is smaller than the amount of heat shrinkage at the heat processing temperature of the transparent heat shrinkable film 42. The amount of heat shrinkage at the heat processing temperature of each of the ionizing radiation cured resin layer 31P, the alignment layers 32, 33, and the transparent support layers 36, 37 is preferably 10% or less, and more preferably 5% or less, of the amount of heat shrinkage at the heat processing temperature of the transparent heat shrinkable film 42.

[0070] According to the above embodiment, the following effects can be obtained. (1) Contraction of the transparent heat-shrinkable film 42 deforms the light-controlling laminate 11 into a convex curved shape so that the light-controlling laminate 11 protrudes from the transparent heat-shrinkable film 42 in a direction toward the second transparent electrode layer 34. Because the surface of the transparent substrate 62 is a concave curved surface that recesses from the transparent heat-shrinkable film 42 toward the second transparent electrode layer 34, the light-controlling laminate 11 itself has a convex curved shape conforming to the surface of the transparent substrate 62. As a result, the light-controlling laminate 11 itself has a shape conforming to the curved surface of the transparent substrate 62, thereby increasing the degree of freedom regarding the viscoelasticity of the first optical transparent adhesive layer 61.

[0071] (2) The shrinkage of the transparent heat-shrinkable film 42 deforms the entire second transparent support layer 36 into a convex curved surface that protrudes from the transparent heat-shrinkable film 42 toward the second transparent electrode layer 34. Furthermore, since the entire light switchable laminate 11 has a convex curved surface that conforms to the concave curved surface of the transparent substrate 62, it is easy to attach the entire light switchable laminate 11 to the curved surface of the transparent substrate 62.

[0072] (3) When the dimming panel 10 has a shape that extends in the second direction D2 and the main shrinkage direction of the transparent heat-shrinkable film 42 is a direction that intersects with the second direction D2, it is easy to bend the dimming stack 11 in a direction in which it is more difficult to bend than the second direction D2. Furthermore, when the main shrinkage direction of the transparent heat-shrinkable film 42 is the first direction D1, it is even easier to bend the dimming stack 11 in the first direction D1, in which it is more difficult to bend the dimming stack 11.

[0073] (4) Since the first heat shrinkage temperature of the transparent heat shrinkable film 42 is lower than the second heat shrinkage temperature, it is also possible to deform the transparent heat shrinkable film 42 so as to suppress thermal deformation of each transparent support layer 36, 37 and the ionizing radiation cured resin layer 31P.

[0074] (5) When viewed from the viewpoint opposite the surface of the photochromic laminate 11, the radius of curvature of the curved surface of the transparent substrate 62 has its smallest value in the main shrinkage direction of the transparent heat-shrinkable film 42. Therefore, the first direction D1 in which the radius of curvature is smallest in the curved shape of the photochromic laminate 11 matches the first direction D1 in which the radius of curvature is smallest in the curved surface of the transparent substrate 62. As a result, the photochromic laminate 11 can easily follow parts of the curved surface of the transparent substrate 62 that are difficult for a planar sheet to follow, making it easier to attach the photochromic laminate 11 to the curved surface of the transparent substrate 62.

[0075] (6) When the thermal processing temperature of the adhesive body is higher than the first heat shrinkage temperature and lower than the second heat shrinkage temperature, it is possible to deform the transparent heat shrinkable film 42 so as to suppress thermal deformation of the transparent support layers 36, 37 and the ionizing radiation cured resin layer 31P when the adhesive body is heated. This makes it possible to suppress a decrease in adhesion between the layers constituting the light control sheet due to heating.

[0076] [Other embodiments] The above embodiment can be modified as follows. 6, the first surface 50A may be a concavely curved surface that is recessed at the center of the first surface 50A in the direction from the light control laminate 11 toward the base laminate 60. The surface of the base laminate 60 may also be a concavely curved surface that is recessed at the center of the first surface 50A in the direction from the light control laminate 11 toward the base laminate 60. For example, the first surface 50A or the surface of the transparent base material 62 may have a concavely curved shape in a cross section including the thickness direction of the light control panel 10 and the first direction D1, and in a cross section including the thickness direction of the light control panel 10 and the second direction D2.

[0077] The heating (Step S4) may be performed simultaneously with the attachment (Step S3), or may be performed between the formation (Step S2) and attachment (Step S3) of the photochromic laminate 11. Note that a manufacturing method in which attachment (Step S3) and heating (Step S4) are performed simultaneously makes it possible to adjust the degree of deformation of the photochromic laminate 11 to match the surface of the transparent substrate 62, and therefore makes it possible to prevent excessive deformation of the photochromic laminate 11 due to heating.

[0078] When viewed from the viewpoint facing the surface of the light control laminate 11, the transparent heat shrinkable film 42 may be smaller than the first transparent film, and the entire transparent heat shrinkable film 42 may be attached to a portion of the first transparent film. In this case, in the light control panel 10, a portion of the surface of the transparent substrate 62 has a size equivalent to a portion of the first transparent film and is recessed in a direction from the transparent heat shrinkable film 42 toward the second transparent electrode layer 34.

[0079] According to this modification, shrinkage of the transparent heat-shrinkable film 42 deforms a portion of the photochromic stack 11 into a convex curved shape so that the portion protrudes from the transparent heat-shrinkable film 42 in a direction toward the second transparent electrode layer 34. The portion of the photochromic stack 11 has a convex curved shape that conforms to a portion of the surface of the transparent substrate 62. Therefore, even if the surface of the transparent substrate 62 includes linear and concave curved shapes in a cross section including the thickness direction of the transparent substrate 62 and the first direction D1, it is easy to attach the photochromic stack 11 to a curved surface of a size corresponding to a portion of the first transparent film.

[0080] In this modified example, the adhesive body may be heated locally only in the area of ​​the adhesive body where the transparent heat-shrinkable film 42 is located. According to this manufacturing method, it is possible to prevent a decrease in adhesion due to heating in the areas of the light controlling sheet that are not heated.

[0081] The light control laminate 11 may include a plurality of transparent heat-shrinkable films 42 on the surface of the first transparent film. In this case, in the light control panel 10, the surface of the transparent substrate 62 has curved surfaces each having a size corresponding to each of the transparent heat-shrinkable films 42, protruding from the transparent heat-shrinkable films 42 in a direction toward the second transparent electrode layer 34.

[0082] According to this modification, the shrinkage of each transparent heat-shrinkable film 42 deforms the portion of the photochromic stack 11 to which the transparent heat-shrinkable film 42 is attached into a convex curved shape so that the transparent heat-shrinkable film 42 protrudes from the transparent heat-shrinkable film 42 toward the second transparent electrode layer 34. The photochromic stack 11 has a shape that conforms to the curved surface of the transparent substrate 62. Therefore, even if the surface of the transparent substrate 62 has a corrugated shape in a cross section including the thickness direction of the transparent substrate 62 and the first direction D1, it is easy to attach the photochromic stack 11 to the curved surface of the transparent substrate 62.

[0083] The transparent heat-shrinkable film 42 may be disposed between the light-controlling layer 31 and the first optically transparent adhesive layer 61. In this case, in the light-controlling panel 10, the curved surface on the surface of the transparent substrate 62 has a convex curve in the direction from the transparent heat-shrinkable film 42 toward the second transparent electrode layer 34. In this modified example, an effect similar to that of (1) above can be obtained. [Explanation of symbols]

[0084] LCM…liquid crystal compound 10...Dimmer 11...Light-control laminate 12...Drive unit 31...Photochromic layer 31P…Ionizing radiation curing resin layer 31LC…Liquid crystal composition 31D…Void 32...Second alignment layer 33...First alignment layer 34...Second transparent electrode layer 35...First transparent electrode layer 36…Second transparent support layer 37...First transparent support layer 42...Transparent heat shrinkable film 61...First optical transparent adhesive layer 62...Transparent base material

Claims

1. a first transparent film having a first transparent electrode layer; a second transparent film having a second transparent electrode layer; a light control layer disposed between the first transparent electrode layer and the second transparent electrode layer, the light control layer being formed by filling a liquid crystal composition into a plurality of gaps defined by the ionizing radiation curable resin layer; A light-control laminate attached to a curved surface of a transparent substrate by a first optical transparent adhesive layer, and changing the haze of the light-control layer by changing a voltage applied between the first transparent electrode layer and the second transparent electrode layer, a transparent heat-shrinkable film disposed on the opposite side of the first transparent film from the side of the light-controlling layer and attached to the first transparent film; A light-controlling laminate comprising:

2. The transparent heat-shrinkable film is attached to the entire first transparent film. The light control laminate according to claim 1 .

3. When viewed from a viewpoint facing the surface of the light-control laminate, the transparent heat-shrinkable film is smaller than the first transparent film, and the entire transparent heat-shrinkable film is attached to a part of the first transparent film. The light control laminate according to claim 1 .

4. A plurality of the transparent heat-shrinkable films are provided. The light control laminate according to claim 3 .

5. The main shrinkage direction of the transparent heat-shrinkable film intersects with the longitudinal direction of the light-control laminate. The light control laminate according to claim 1 .

6. The main shrinkage direction of the transparent heat-shrinkable film is perpendicular to the longitudinal direction of the light-control laminate. The light control laminate according to claim 1 .

7. the heat shrinkage temperature of the transparent heat shrinkable film is lower than the heat shrinkage temperatures of a first transparent support layer that supports the first transparent electrode layer in the first transparent film, a second transparent support layer that supports the second transparent electrode layer in the second transparent film, and the ionizing radiation curable resin layer; The light control laminate according to claim 1 .

8. a light-control laminate; A transparent substrate having a curved surface; a first optical transparent adhesive layer disposed between the curved surface and the light-controlling laminate to attach the light-controlling laminate to the curved surface; The light-controlling laminate is a first transparent film having a first transparent electrode layer; a second transparent film having a second transparent electrode layer; a light control layer disposed between the first transparent electrode layer and the second transparent electrode layer, the light control layer being formed by filling a liquid crystal composition into a plurality of gaps defined by the ionizing radiation curable resin layer; The haze of the light-controlling layer is changed by changing a voltage applied between the first transparent electrode layer and the second transparent electrode layer, A transparent heat-shrinkable film that bends the light-controlling laminate to conform to the curved surface by heating, the transparent heat-shrinkable film being arranged on the opposite side of the first transparent film from the light-controlling layer and attached to the first transparent film, A dimming board characterized by:

9. the transparent heat shrinkable film is disposed on the opposite side of the light control layer from the first optical transparent adhesive layer, The curved surface is a concave curved surface. The dimming plate according to claim 8.

10. the transparent heat shrinkable film is disposed between the light control layer and the first optical transparent adhesive layer; The curved surface is a convex curved surface. The dimming plate according to claim 8.

11. When viewed from a viewpoint facing the surface of the light-controlling laminate, the radius of curvature of the curved surface has a minimum value in the main shrinkage direction of the transparent heat-shrinkable film. The dimming plate according to claim 8.

12. A method for manufacturing a light control panel, comprising: attaching a light control laminate to a curved surface of a transparent substrate using an optical transparent adhesive layer; The light-controlling laminate is a first transparent electrode layer; A second transparent electrode layer; a light control layer disposed between the first transparent electrode layer and the second transparent electrode layer, the light control layer being formed by filling a liquid crystal composition into a plurality of gaps defined by the ionizing radiation curable resin layer; a transparent heat-shrinkable film that bends the ionizing radiation cured resin layer to conform to the curved surface when heated to a first heat-shrinkage temperature, The haze of the light-controlling layer is changed by changing a voltage applied between the first transparent electrode layer and the second transparent electrode layer, heating the light-controlling laminate to a thermal processing temperature equal to or higher than the first heat shrinkage temperature; A method for manufacturing a light control panel.

13. the thermal processing temperature is lower than the heat shrinkage temperatures of a first transparent support layer supporting the first transparent electrode layer, a second transparent support layer supporting the second transparent electrode layer, and the ionizing radiation curable resin layer; The method for manufacturing the light control panel according to claim 12.

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