Dimming sheet, and method for manufacturing the same

Abstract

To provide a dimming sheet capable of suppressing an increase in the number of wirings and a method for manufacturing the dimming sheet.SOLUTION: A dimming sheet 10 comprises: a dimming layer 20 including a liquid crystal compound and a dichroic pigment; and a first transparent electrode layer 31 and a second transparent electrode layer 32 that are a pair of transparent electrode layers holding the dimming layer 20 therebetween. As viewed from a position opposed to a front surface of the dimming sheet 10, the first transparent electrode layer 31 includes non-conductive parts extending linearly and conductive parts sectioned by the non-conductive parts, and a portion having conductivity in the second transparent electrode layer 32 overlaps each of the conductive parts and the non-conductive parts. An average transmissivity of light in an infrared region in the dimming sheet 10 in an opaque state is 64% or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a light controlling sheet and a method for manufacturing the light controlling sheet. [Background technology]

[0002] The light-adjusting sheet includes a light-adjusting layer containing a liquid crystal composition and a pair of transparent electrode layers sandwiching the light-adjusting layer. Each transparent electrode layer is supported by a transparent support layer on the side opposite the light-adjusting layer. Since the alignment state of the liquid crystal composition changes depending on whether or not a voltage is applied to the transparent electrode layer, it is possible to switch between a transparent state in which light passes through the light-adjusting layer and an opaque state in which light transmission through the light-adjusting layer is suppressed by scattering or the like.

[0003] To improve design and expand functionality, a structure has been proposed in which the light-control sheet is divided into multiple regions and each region can be switched between a transparent state and an opaque state (see, for example, Patent Document 1). For example, the light-control sheet is divided into multiple regions by partially insulating the transparent electrode layer by cutting with a cutting device or irradiating it with a laser. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-60128 A Summary of the Invention [Problem to be solved by the invention]

[0005] When dividing the light-controlling sheet into multiple regions using a cutting device, the transparent support layer located on the surface of the light-controlling sheet is also cut together with the transparent electrode layer. Therefore, it is necessary to protect the surface of the cut light-controlling sheet, and if the cut part is rough, it will lead to a deterioration in the appearance of the light-controlling sheet.

[0006] On the other hand, when dividing the light-control sheet into multiple regions by laser irradiation, the laser light passes through the transparent support layer, so cutting of the surface of the light-control sheet is avoided. However, the laser light also passes through the light-control layer, so both of the pair of transparent electrode layers are insulated. Therefore, for each divided region, it is necessary to connect wiring for applying voltage to each of the transparent electrode layers sandwiching the light-control layer. Therefore, the number of wirings increases, and the manufacturing of the light-control sheet and the control of the application of voltage become cumbersome. [Means for solving the problem]

[0007] Various aspects of a light controlling sheet and a manufacturing method thereof for solving the above problems will be described below. [Aspect 1] A light-adjusting layer comprising a transparent polymer layer including a plurality of domains, a liquid crystal composition filling the domains, the liquid crystal composition including a liquid crystal compound and a dichroic dye, and a pair of transparent electrode layers, a first transparent electrode layer and a second transparent electrode layer, sandwiching the light-adjusting layer, the first transparent electrode layer and the second transparent electrode layer being a pair of transparent electrode layers sandwiching the light-adjusting layer, the first transparent electrode layer and the second transparent electrode layer changing the orientation of the liquid crystal compound and the dichroic dye in response to a change in the potential difference between the pair of transparent electrode layers, thereby switching from a colored opaque state to a transparent state, wherein, when viewed from a position facing the surface of the light-adjusting sheet, the first transparent electrode layer includes a linearly extending non-conductive portion and a conductive portion separated by the non-conductive portion, the conductive portions of the second transparent electrode layer overlap with each of the conductive portions and the non-conductive portions, and the average transmittance of light in the infrared region through the light-adjusting sheet in the opaque state is 64% or less.

[0008] According to the above configuration, since the light in the infrared region is absorbed by the light control layer, it is easy to form a non-conductive part in only one of the two transparent electrode layers by using an infrared laser. Therefore, it is possible to prevent an increase in the number of wirings required to connect the transparent electrode layers to the power source, and to prevent the layout of the wiring and the control of the input of the voltage signal from becoming complicated.

[0009] [Aspect 2] The light-controlling sheet according to [Aspect 1], wherein the proportion of the dichroic dye in the light-controlling layer is from 1% by mass to 10% by mass. According to the above-mentioned configuration, it becomes easier to obtain sufficient light absorption in the infrared region in the light-adjusting layer. In addition, the difference in color between the transparent state and the opaque state of the light-adjusting sheet becomes easier to clearly recognize, and further, it is possible to suppress the precipitation of the dichroic dye and the increase in the manufacturing cost of the light-adjusting sheet.

[0010] [Aspect 3] A light-controlling sheet according to [Aspect 1] or [Aspect 2], wherein the proportion of the transparent polymer layer in the light-controlling layer is 20% by mass or more and 80% by mass or less. According to the above-mentioned configuration, the domain is appropriately secured in the transparent polymer layer, and the structure of the light control layer in which the liquid crystal composition is dispersed in the transparent polymer layer is suitably formed.

[0011] [Aspect 4] A light-controlling sheet according to any one of [Aspect 1] to [Aspect 3], wherein the material of each of the first transparent electrode layer and the second transparent electrode layer contains indium tin oxide or a silver alloy. According to the above configuration, it is preferably possible to process only one of the two transparent electrode layers using an infrared laser.

[0012] [Aspect 5] A light-controlling sheet described in any one of [Aspect 1] to [Aspect 4], comprising a pair of transparent support layers sandwiching the light-controlling layer and the pair of transparent electrode layers, wherein the material of each of the pair of transparent support layers contains polyethylene terephthalate. According to the above configuration, it is preferably possible to process only one of the two transparent electrode layers using an infrared laser.

[0013] [Aspect 6] A method for manufacturing a light-controlling sheet, comprising: forming a laminated sheet including a transparent polymer layer including a plurality of domains; a light-controlling layer including a liquid crystal composition filling the domains, the liquid crystal composition including a liquid crystal compound and a dichroic dye; and a pair of transparent electrode layers, a first transparent electrode layer and a second transparent electrode layer, sandwiching the light-controlling layer; and irradiating the laminated sheet with an infrared laser from the side of the light-controlling layer where the first transparent electrode layer is located, to form linear non-conductive portions and conductive portions separated by the non-conductive portions in the first transparent electrode layer, wherein the laminated sheet has an average transmittance of 64% or less for light in the infrared region.

[0014] According to the above-mentioned manufacturing method, since the light in the infrared region is absorbed by the light control layer, it is easy to form a non-conductive part only on one of the two transparent electrode layers, and therefore it is possible to reduce the wiring required to connect the transparent electrode layer to the power source. Effect of the Invention

[0015] According to the present invention, it is possible to suppress an increase in the number of wirings required to drive the light controlling sheet. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram showing a cross-sectional structure of a light controlling sheet according to one embodiment. [Diagram 2] FIG. 2 is a diagram showing a planar structure of a light controlling sheet according to one embodiment. [Diagram 3] FIG. 3 is an enlarged view showing a part of the cross-sectional structure of the light controlling sheet according to one embodiment. [Figure 4] FIG. 4 is a diagram showing the structure of a light controlling layer of a light controlling sheet according to one embodiment. [Diagram 5] FIG. 5 is a diagram showing a method for manufacturing a light controlling sheet according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] An embodiment of a light controlling sheet and a method for producing the same will be described with reference to FIGS. 1 to 5. FIG. [Layer structure of light control sheet] The layer structure of the light-adjusting sheet will be described with reference to Fig. 1. As shown in Fig. 1, the light-adjusting sheet 10 includes a light-adjusting layer 20, a first transparent electrode layer 31, a second transparent electrode layer 32, a first transparent support layer 41, and a second transparent support layer 42. The light-adjusting layer 20 is sandwiched between the first transparent electrode layer 31 and the second transparent electrode layer 32, and is in contact with these transparent electrode layers 31 and 32. The first transparent support layer 41 supports the first transparent electrode layer 31 on the side opposite the light-adjusting layer 20 with respect to the first transparent electrode layer 31, and the second transparent support layer 42 supports the second transparent electrode layer 32 on the side opposite the light-adjusting layer 20 with respect to the second transparent electrode layer 32.

[0018] The light control layer 20 includes a transparent polymer layer having a large number of voids and a liquid crystal composition held in the voids. The light control layer 20 has, for example, a polymer dispersion type liquid crystal or a polymer network type liquid crystal structure.

[0019] Each of the first transparent electrode layer 31 and the second transparent electrode layer 32 has electrical conductivity and is transparent to light in the visible region. The material of the transparent electrode layers 31 and 32 is, for example, indium tin oxide, fluorine-doped tin oxide, tin oxide, zinc oxide, carbon nanotubes, poly(3,4-ethylenedioxythiophene), silver, a silver alloy, or the like.

[0020] Each of the first transparent support layer 41 and the second transparent support layer 42 is a base material that is transparent to light in the visible region. The material of the transparent support layers 41 and 42 is, for example, a synthetic resin or an inorganic compound. Examples of the synthetic resin include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyacrylates such as polymethyl methacrylate, polycarbonates, polyolefins, etc. Examples of the inorganic compound include silicon dioxide, silicon oxynitride, silicon nitride, etc.

[0021] The light-adjusting sheet 10 has a sheet region RS, a first end region RE1, and a second end region RE2. The light-adjusting layer 20 and the layers sandwiching the light-adjusting layer 20 are located in the sheet region RS. In other words, the sheet region RS is a region having a structure in which the light-adjusting layer 20 is sandwiched between a pair of transparent electrode layers 31 and 32.

[0022] The first end region RE1 and the second end region RE2 are located at the ends of the light-adjusting sheet 10. In the first end region RE1, the first transparent support layer 41 and the first transparent electrode layer 31 extend from the sheet region RS. That is, in the first end region RE1, the first transparent electrode layer 31 is exposed from the light-adjusting layer 20 and the second transparent electrode layer 32 and the second transparent support layer 42. A first wiring section 51 for electrically connecting the first transparent electrode layer 31 and a power source is connected to the exposed surface of the first transparent electrode layer 31.

[0023] In the second end region RE2, the second transparent support layer 42 and the second transparent electrode layer 32 extend from the sheet region RS. That is, in the second end region RE2, the second transparent electrode layer 32 is exposed from the light control layer 20, the first transparent electrode layer 31, and the first transparent support layer 41. A second wiring section 52 for electrically connecting the second transparent electrode layer 32 and a power source is connected to the exposed surface of the second transparent electrode layer 32.

[0024] Each of the first wiring portion 51 and the second wiring portion 52 includes, for example, a conductive adhesive layer and a wiring substrate. The conductive adhesive layer is formed of, for example, an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), an isotropic conductive film (ICF), an isotropic conductive paste (ICP), or the like. The wiring substrate is, for example, a flexible printed circuit (FPC). Alternatively, each of the first wiring portion 51 and the second wiring portion 52 may have a structure in which a conductive material such as a conductive tape and a conductor are joined by soldering.

[0025] The transparent electrode layers 31 and 32 are electrically connected to a control unit 55 via wiring units 51 and 52. The control unit 55 applies a driving voltage, which is an AC voltage for changing the alignment state of the liquid crystal molecules, to the transparent electrode layers 31 and 32 through the wiring units 51 and 52. The light controlling sheet 10, the control unit 55, and the wiring units 51 and 52 constitute a light controlling device.

[0026] The light-controlling sheet 10 is attached to a transparent substrate, which is the object to which it is attached. The transparent substrate is a glass substrate or a resin substrate. Examples of transparent substrates include windowpanes mounted on moving objects such as vehicles and aircraft, windowpanes installed in buildings, and partitions installed inside vehicles or indoors. The surface to which the light-controlling sheet 10 is attached is flat or curved. The light-controlling sheet 10 may also be sandwiched between two transparent substrates.

[0027] [Plane structure of light control sheet] 2 and 3, the arrangement of the regions RS, RE1, RE2 and the wiring portions 51, 52 in the light controlling sheet 10 will be described. In Fig. 2, for ease of understanding, the sheet region RS is indicated by dots.

[0028] 2, the sheet area RS has a plurality of light control sections 60 and one or more insulating sections 61. When viewed from a position facing the surface of the light control sheet 10, the insulating sections 61 extend linearly and separate adjacent light control sections 60. In other words, the sheet area RS is divided into a plurality of light control sections 60 by the insulating sections 61.

[0029] 2 shows an example in which the dimming section 60 and the insulating section 61 extend in one direction, and three dimming sections 60 extending in a strip shape are partitioned by two insulating sections 61. However, the present invention is not limited to this example, and the number and shapes of the dimming sections 60 and the insulating sections 61 are arbitrary as long as the dimming section 60 is partitioned by linear insulating sections 61.

[0030] 3 shows a cross-sectional structure in the vicinity of the insulating portion 61. The first transparent electrode layer 31 has a conductive portion 33 and a non-conductive portion 35. The non-conductive portion 35 is a portion that has lost conductivity as a result of the first transparent electrode layer 31 being destroyed or modified by laser irradiation. In other words, the non-conductive portion 35 is a laser processing mark, and extends linearly when viewed from a position facing the surface of the light adjusting sheet 10. The conductive portion 33 is a portion that has not been irradiated with a laser and has conductivity. On the other hand, the second transparent electrode layer 32 does not have a non-conductive portion. In other words, the second transparent electrode layer 32 is entirely made up of a conductive portion .

[0031] In the sheet region RS, when viewed from a position facing the surface of the light adjusting sheet 10, the portion where the conductive portion 33 is located is the light adjusting portion 60, and the portion where the non-conductive portion 35 is located is the insulating portion 61. That is, in the light adjusting portion 60, both the first transparent electrode layer 31 and the second transparent electrode layer 32 are conductive, and in the insulating portion 61, the first transparent electrode layer 31 is not conductive, and the second transparent electrode layer 32 is conductive. The conductive portions 33 of the first transparent electrode layer 31 in adjacent light adjusting portions 60 are insulated from each other by the non-conductive portion 35 being located therebetween as the insulating portion 61.

[0032] Returning to FIG. 2, the first end region RE1 has a first connection portion 70 and an end insulating portion 71. The first connection portion 70 extends continuously from the dimming portion 60 of the sheet region RS. The conductive portion 33 of the first transparent electrode layer 31 is located in the first connection portion 70. The end insulating portion 71 extends continuously and linearly from the insulating portion 61 of the sheet region RS. The non-conductive portion 35 of the first transparent electrode layer 31 is located in the end insulating portion 71. The conductive portions 33 of the first transparent electrode layer 31 in adjacent first connection portions 70 are insulated from each other by the non-conductive portion 35 being located therebetween as the end insulating portion 71.

[0033] In this manner, a first connection section 70 that electrically connects the dimming section 60 and the first transparent electrode layer 31 is provided for each dimming section 60, and adjacent first connection sections 70 are separated by end insulating sections 71. Then, the first wiring section 51 is connected to the first transparent electrode layer 31 of each first connection section 70.

[0034] The second end region RE2 does not have an insulating portion. That is, the entire second transparent electrode layer 32 included in the sheet region RS and the second end region RE2 is a uniform conductive film. The second end region RE2 has a second connection portion 80. The second wiring portion 52 is connected to the second transparent electrode layer 32 of the second connection portion 80. In this manner, one second wiring portion 52 is connected to the second end region RE2.

[0035] 2 shows a form in which the first end region RE1 and the second end region RE2 are arranged along opposing sides of the light adjusting sheet 10, but the positional relationship between the first end region RE1 and the second end region RE2 may be set arbitrarily. In other words, the first connection portion 70 and the second connection portion 80 may be arranged along opposing sides of the light adjusting sheet 10, or may have an arrangement different from this arrangement.

[0036] [Configuration of light control layer] The detailed configuration of the light-controlling layer 20 will be described with reference to Fig. 4. Fig. 4 is a schematic diagram showing the laminated portion of the light-controlling layer 20 and the transparent electrode layers 31 and 32 in the cross-sectional structure of the light-controlling sheet 10, with the configuration of the light-controlling layer 20 emphasized.

[0037] The light-controlling layer 20 includes a transparent polymer layer 21, a liquid crystal composition 22, and a spacer 23. The transparent polymer layer 21 is a cured product of a photopolymerizable compound. The transparent polymer layer 21 defines a plurality of domains 21D dispersed therein. In other words, the domains 21D are voids. The shape of the domains 21D is, for example, substantially spherical, substantially ellipsoidal, or irregular. The space within the domains 21D is filled with the liquid crystal composition 22.

[0038] The proportion of the transparent polymer layer 21 in the light-controlling layer 20 is preferably 20% by mass or more and 80% by mass or less, and more preferably 30% by mass or more and 60% by mass or less. When the proportion of the transparent polymer layer 21 is within the above range, the domain 21D is appropriately secured. Within the above range, the greater the proportion of the transparent polymer layer 21, the greater the mechanical strength of the transparent polymer layer 21 can be increased, and the smaller the proportion of the transparent polymer layer 21, the greater the driving voltage of the light-controlling sheet 10 can be reduced.

[0039] The photopolymerizable compound of the material of the transparent polymer layer 21 may be an ultraviolet-curable compound or an electron beam-curable compound. The photopolymerizable compound has compatibility with the liquid crystal composition 22. When the photopolymerizable compound is an ultraviolet-curable compound, the controllability of the dimensions of the domain 21D is improved. The photopolymerizable compound may be one type of polymerizable compound or a combination of two or more types of polymerizable compounds.

[0040] An example of an ultraviolet curable compound includes a polymerizable unsaturated bond at the end of the molecular structure. Another example of an ultraviolet curable compound includes a polymerizable unsaturated bond at a position other than the end of the molecular structure. Examples of ultraviolet curable compounds include acrylate compounds, methacrylate compounds, thiol compounds, styrene compounds, and oligomers of each of these compounds. Acrylate compounds include diacrylate compounds, triacrylate compounds, and tetraacrylate compounds. Examples of acrylate compounds include butyl ethyl acrylate, ethylhexyl acrylate, and cyclohexyl acrylate. Methacrylate compounds include dimethacrylate compounds, trimethacrylate compounds, and tetramethacrylate compounds. Examples of methacrylate compounds include N,N-dimethylaminoethyl methacrylate, phenoxyethyl methacrylate, methoxyethyl methacrylate, and tetrahydrofurfuryl methacrylate. Examples of thiol compounds include 1,3-propanedithiol and 1,6-hexanedithiol. Examples of styrene compounds include styrene and methylstyrene.

[0041] The liquid crystal composition 22 includes a liquid crystal compound 22L and a dichroic dye 22P. The liquid crystal composition 22 may further include a viscosity reducing agent, an antifoaming agent, an antioxidant, a weather resistance agent, etc. Examples of the weather resistance agent include an ultraviolet absorber and a light stabilizer.

[0042] The liquid crystal compound 22L is a non-polymerizable compound. The dielectric constant of the liquid crystal compound 22L in the long axis direction is higher than the dielectric constant of the liquid crystal compound 22L in the short axis direction. That is, the liquid crystal compound 22L has a positive dielectric anisotropy.

[0043] The liquid crystal compound 22L is, for example, a Schiff base-based, azo-based, azoxy-based, biphenyl-based, terphenyl-based, benzoic acid ester-based, tolan-based, pyrimidine-based, pyridazine-based, cyclohexane carboxylate-based, phenylcyclohexane-based, biphenylcyclohexane-based, dicyanobenzene-based, naphthalene-based, or dioxane-based compound. The liquid crystal compound 22L may be one type of liquid crystal compound or a combination of two or more types of liquid crystal compounds.

[0044] The dichroic dye 22P has an elongated molecular shape, and the absorbance in the visible region in the long axis direction of the molecule is greater than the absorbance in the short axis direction. The dichroic dye 22P exhibits a predetermined color when the long axis direction is substantially perpendicular to the incident direction of light. The color exhibited by the dichroic dye 22P is, for example, black or a color close to black. The dichroic dye 22P is driven by a guest-host type with the liquid crystal compound 22L as a host to exhibit color.

[0045] Furthermore, the dichroic dye 22P has an absorptivity for light in the infrared region, which is light in the wavelength range of 780 nm or more and 2000 nm or less. The dichroic dye 22P is, for example, polyiodine, an azo compound, an anthraquinone compound, a naphthoquinone compound, an azomethine compound, a tetrazine compound, a quinophthalone compound, a merocyanine compound, a perylene compound, or a dioxazine compound. The dichroic dye 22P may be one type of dye or a combination of two or more types of dyes. From the viewpoint of increasing light resistance and dichroic ratio, the dichroic dye 22P is preferably at least one selected from the group consisting of an azo compound and an anthraquinone compound, and more preferably an azo compound.

[0046] The proportion of the dichroic dye 22P in the light-adjusting layer 20 is preferably 1% by mass or more and 10% by mass or less, and more preferably 2% by mass or more and 5% by mass or less. When the proportion of the dichroic dye 22P is 1% by mass or more, the difference in color of the light-adjusting sheet 10 between the transparent state and the opaque state becomes more clearly recognizable. In addition, the light-adjusting layer 20 is more likely to absorb light in the infrared region sufficiently. When the proportion of the dichroic dye 22P is 10% by mass or less, precipitation of particles formed by aggregation of the dichroic dye 22P can be suppressed.

[0047] The spacers 23 are dispersed throughout the transparent polymer layer 21. The spacers 23 determine the thickness of the light-controlling layer 20 around the spacers 23, thereby making the thickness of the light-controlling layer 20 uniform. The spacers 23 may be bead spacers or photospacers formed by exposing and developing a photoresist. The spacers 23 may be colorless and transparent, or colored and transparent, so long as they are translucent. The color exhibited by the colored and transparent spacers 23 is preferably the same color as the color exhibited by the dichroic dye 22P.

[0048] Since the thickness of the photochromic layer 20 roughly corresponds to the size of the spacers 23, the thickness of the photochromic layer 20 can be controlled by changing the average particle size of the spacers 23. As an example, the average particle size of the spacers 23 is 10 μm or more and 30 μm or less in terms of the median diameter D50. In this case, the thickness of the photochromic layer 20 is 10 μm or more and 30 μm or less.

[0049] [Electrical configuration of the dimming device] The voltage signal input from the control unit 55 to each first wiring unit 51 is input to the first transparent electrode layer 31 of the dimming unit 60 that is in electrical conduction with the first connection unit 70 to which the first wiring unit 51 is connected, for each first wiring unit 51. That is, a voltage signal is input to the first transparent electrode layer 31 of each dimming unit 60 separately for each dimming unit 60.

[0050] On the other hand, the voltage signal input from the control unit 55 to the second wiring unit 52 is input to the second transparent electrode layer 32. That is, a voltage signal common to each dimming unit 60 is input to the second transparent electrode layer 32 of each dimming unit 60.

[0051] In the above configuration, the control unit 55 can control the application of a drive voltage to the dimming unit 60 for each dimming unit 60 by controlling the input of a voltage signal to the first transparent electrode layer 31 for each dimming unit 60 while inputting a common voltage signal to the second transparent electrode layer 32 of each dimming unit 60.

[0052] The light control section 60 switches from one of a transparent state and an opaque state to the other based on a change in the alignment state of the liquid crystal composition 22. In the opaque state, the light control sheet 10 is colored, and in the transparent state, the light control sheet 10 is colorless or nearly colorless and transparent. In the opaque state, the total light transmittance of the light control sheet 10 is lower than in the transparent state, and the haze of the light control sheet 10 is higher than in the transparent state.

[0053] When no driving voltage is applied, the liquid crystal compound 22L and the dichroic dye 22P are randomly oriented in the long axis direction. Therefore, the light incident on the light control section 60 is scattered in various directions in the light control layer 20. In addition, since the long axis direction of the dichroic dye 22P is randomly oriented, at least a part of the dichroic dye 22P is colored. Therefore, when no driving voltage is applied, the light control section 60 is in an opaque state and appears colored.

[0054] When the liquid crystal compound 22L has a positive dielectric anisotropy, the liquid crystal compound 22L and the dichroic dye 22P are oriented such that their major axis direction is aligned with the electric field direction when a drive voltage is applied. That is, the liquid crystal compound 22L and the dichroic dye 22P change their orientation so that their major axis direction is aligned with the thickness direction of the light-adjusting layer 20. As a result, light scattering in the light-adjusting layer 20 and coloring of the dichroic dye 22P are suppressed, and light is more easily transmitted through the light-adjusting section 60. Therefore, when a drive voltage is applied, the light-adjusting section 60 is in a transparent state.

[0055] [Characteristics of light control sheet] The optical properties of the light-adjusting sheet 10 will be described. The light-adjusting sheet 10 of this embodiment contains a dichroic dye 22P that absorbs light in the infrared region. Therefore, the light-adjusting sheet 10 in the opaque state is absorptive of light in the infrared region. In other words, in the light-adjusting sheet 10 in the opaque state, the transmittance of light in the infrared region is suppressed. Specifically, the average transmittance of light in the infrared region in the light-adjusting sheet 10 in the opaque state is 64% or less.

[0056] The above-mentioned average infrared light transmittance can be adjusted by the type and ratio of the dichroic dye 22P contained in the light-adjusting layer 20. For example, when a light-adjusting sheet 10 that exhibits black color in an opaque state is constructed by mixing a plurality of types of dichroic dyes 22P, the average infrared light transmittance can be increased by increasing the ratio of the dichroic dye 22P that exhibits high absorption in the long wavelength region of the visible region.

[0057] In addition, in the opaque light-adjusting sheet 10, the total light transmittance of light in the visible region is preferably 20% or less, and more preferably 5% or less. On the other hand, in the transparent light-adjusting sheet 10, the total light transmittance of light in the visible region is preferably 40% or more, and more preferably 50% or more. This allows a clear difference in transparency between the transparent state and the opaque state to be obtained.

[0058] [Manufacturing method of light control sheet] A method for producing the light controlling sheet 10 will be described with reference to FIG. First, a laminate is formed including the light control layer 20, the transparent electrode layers 31 and 32, and the transparent support layers 41 and 42. At this time, the first transparent electrode layer 31 is a uniform conductive film in which the non-conductive portion 35 is not formed.

[0059] In detail, first, a first transparent support layer 41 on which a first transparent electrode layer 31 is laminated, and a second transparent support layer 42 on which a second transparent electrode layer 32 is laminated are prepared. The transparent electrode layers 31 and 32 are formed by a known film formation method such as sputtering.

[0060] Subsequently, a coating film for forming the light control layer 20 is formed between the first transparent electrode layer 31 and the second transparent electrode layer 32. The coating film contains a photopolymerizable compound, a liquid crystal compound 22L, a dichroic dye 22P, and a polymerization initiator for initiating polymerization of the photopolymerizable compound. The polymerization initiator is, for example, a diketone compound, an acetophenone compound, a benzoin compound, a benzophenone compound, a thioxanthone compound, an oxime ester compound, or the like. The coating film may contain only a single type of polymerization initiator, or may contain multiple types of polymerization initiators.

[0061] The spacers 23 may be contained in a coating liquid for forming the coating film, or may be dispersed in the coating film when the coating film is formed. The laminate sandwiching the coating film is irradiated with light to polymerize the photopolymerizable compound, whereby phase separation of the liquid crystal composition 22 occurs, and the light control layer 20 is formed. The light that polymerizes the photopolymerizable compound is ultraviolet light or an electron beam. The light that polymerizes the photopolymerizable compound may be irradiated toward the first transparent support layer 41, may be irradiated toward the second transparent support layer 42, or may be irradiated toward both the first transparent support layer 41 and the second transparent support layer 42.

[0062] From the laminate obtained as described above, a laminate sheet 90 including the light-adjusting layer 20, the transparent electrode layers 31 and 32, and the transparent support layers 41 and 42 is cut into the desired shape of the light-adjusting sheet 10. In the laminate sheet 90, the orientations of the liquid crystal compound 22L and the dichroic dye 22P contained in the light-adjusting layer 20 are random, and the laminate sheet 90 is opaque. The average infrared light transmittance of the laminate sheet 90 is 64% or less, similar to that of the light-adjusting sheet 10 in an opaque state.

[0063] 5, the laminated sheet 90 is irradiated with a laser La. In detail, a laser irradiation unit 100 of a laser device is disposed in a position facing the first transparent support layer 41, and the laser La is irradiated to regions of the laminated sheet 90 that will become the insulating parts 61, 71 from the side where the first transparent electrode layer 31 is located with respect to the light-controlling layer 20.

[0064] The wavelength of the laser is in the infrared region. For example, the wavelength of the laser is preferably 1000 nm or more and 1200 nm or less. The medium of the laser is not particularly limited. For example, a Nd:YAG laser, a Nd:YVO4 laser, a CO2 laser, a semiconductor laser, etc. can be used.

[0065] The laser La irradiated to the laminated sheet 90 penetrates the first transparent support layer 41 and enters the first transparent electrode layer 31. As a result, the first transparent electrode layer 31 is destroyed or modified, losing its conductivity, and a non-conductive portion 35 is formed.

[0066] Furthermore, a part of the laser La that has entered the first transparent electrode layer 31 enters the switchable layer 20. Here, the switchable layer 20 has light absorption properties in the infrared region due to the inclusion of the dichroic dye 22P. Therefore, the laser La that has entered the switchable layer 20 is absorbed by the switchable layer 20. This prevents the laser La from passing through the switchable layer 20 and entering the second transparent electrode layer 32. As a result, the formation of a non-conductive portion in the second transparent electrode layer 32 is prevented, and an insulating portion 61 in which only the first transparent electrode layer 31 has lost conductivity can be suitably formed.

[0067] In general, the absorption spectrum of light in the infrared region originating from the dichroic dye 22P does not have a steep peak only at a specific wavelength in the infrared region, and the transmittance decreases throughout the entire infrared region when the average infrared light transmittance in the laminated sheet 90 decreases. When the average infrared light transmittance in the laminated sheet 90 is 64% or less, the laser La having a wavelength in the infrared region is suitably prevented from reaching the second transparent electrode layer 32 and processing the second transparent electrode layer 32. Furthermore, if the average infrared light transmittance of the laminate sheet 90 is 60% or less, the laser beam La is more effectively prevented from passing through the light-switching layer 20 and entering the second transparent electrode layer 32.

[0068] In addition, since the absorption of light in the infrared region originating from the dichroic dye 22P is large around wavelengths of 1000 nm to 1500 nm, using a laser La with a wavelength of 1000 nm or more and 1200 nm or less can more effectively prevent the laser La from passing through the dimming layer 20 and entering the second transparent electrode layer 32.

[0069] After irradiation with the laser La, the first end region RE1 is formed by removing the light-adjusting layer 20, the second transparent electrode layer 32, and the second transparent support layer 42 near the end of the laminated sheet 90. Also, the second end region RE2 is formed by removing the light-adjusting layer 20, the first transparent electrode layer 31, and the first transparent support layer 41 near the other end of the laminated sheet 90. With the formation of the first end region RE1 and the second end region RE2, a sheet region RS is formed.

[0070] In this manner, the light controlling sheet 10 is formed. Then, the first wiring portion 51 is connected to each of the first connection portions 70 in the first end region RE1, and the second wiring portion 52 is connected to the second connection portions 80 in the second end region RE2.

[0071] In the above manufacturing method, since the laser is absorbed in the light control layer 20, it is easy to form the non-conductive portion 35 only in the first transparent electrode layer 31. As a result, in the light control sheet 10, a voltage signal can be input to the entire second transparent electrode layer 32 from one second wiring portion 52. Therefore, compared to the case where both the first transparent electrode layer 31 and the second transparent electrode layer 32 are insulated for each light control section 60 and wiring portions are provided in each transparent electrode layer 31, 32, that is, the case where separate voltage signals are input to the second transparent electrode layer 32 of each light control section 60, it is possible to prevent the arrangement of the wiring portions and the control of the input of the voltage signal from becoming complicated.

[0072] Even if the laser is not absorbed in the light-adjusting layer 20, it is not impossible to form a non-conductive portion in only one of the transparent electrode layers by controlling the laser irradiation conditions, but in this case, precise control of the laser focus, output, scanning speed, and other conditions is required. In contrast, in this embodiment, the laser is absorbed in the light-adjusting layer 20, which allows for more leeway in controlling the laser irradiation conditions, thereby reducing the burden required for manufacturing the light-adjusting sheet 10.

[0073] [Example] The above-mentioned light controlling sheet will be described using specific examples and comparative examples. Example 1 A liquid crystal compound, a dichroic dye, a photopolymerizable compound, and a polymerization initiator were mixed to generate a coating liquid for forming a light-controlling layer. Details of the materials are as follows. The ratio of each material in the coating liquid was 51% by mass of the liquid crystal compound, 4% by mass of the dichroic dye, 44% by mass of the photopolymerizable compound and polymerization initiator, and 1% by mass of the spacer.

[0074] Liquid crystal compounds: Cyanobiphenyl compounds ·Dichroic dye: Black dichroic dye (YH-428, Mitsui Chemicals Fine Co., Ltd.) Photopolymerizable compound (UV-curable compound): A mixture of isobornyl acrylate, pentaerythritol triacrylate, and urethane acrylate Polymerization initiator: 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, BASF Japan) Spacer: Polymethyl methacrylate black spherical particles (particle size: 25 μm)

[0075] A first sheet, which is a laminate of the first transparent support layer and the first transparent electrode layer, was prepared by forming a first transparent electrode layer on the first transparent support layer by sputtering. Similarly, a second sheet, which is a laminate of the second transparent support layer and the second transparent electrode layer, was prepared by forming a second transparent electrode layer on the second transparent support layer by sputtering. For each of the first transparent support layer and the second transparent support layer, the material is polyethylene terephthalate and the thickness is 125 μm. For each of the first transparent electrode layer and the second transparent electrode layer, the material is indium tin oxide (ITO) and the thickness is 30 nm.

[0076] The coating liquid was applied to the first sheet to form a coating film on the first transparent electrode layer. The coating film had a thickness of 25 μm. Then, the second sheet was laminated to the first sheet on which the coating film was formed, to obtain a laminate of the first sheet, the coating film, and the second sheet.

[0077] Next, the first transparent support layer of the laminate was irradiated with ultraviolet light of 365 nm to form a light-controlling layer. The intensity of the ultraviolet light was 7.2 mW / cm. 2 The irradiation time of the ultraviolet light was 120 seconds. As a result, a laminated sheet including a light control layer, a pair of transparent electrode layers, and a pair of transparent support layers was obtained.

[0078] The laminate sheet was irradiated with a laser from the side where the first transparent support layer was located with respect to the light-controlling layer, to form a non-conductive portion in the first transparent electrode layer. The laser irradiation conditions were as follows. Type: IR semiconductor laser ·Wavelength: 1064nm Spot diameter: 30μm This resulted in the production of the light controlling sheet of Example 1 having a plurality of light controlling sections separated by insulating sections.

[0079] Example 2 The light-controlling sheet of Example 2 was obtained using the same materials and processes as Example 1, except that the proportions of each material in the coating liquid for forming the light-controlling layer were changed to 52 mass% liquid crystal compound, 3 mass% dichroic dye, 44 mass% photopolymerizable compound and polymerization initiator, and 1 mass% spacer.

[0080] Example 3 The light-controlling sheet of Example 3 was obtained using the same materials and processes as in Example 1, except that the ratio of each material in the coating liquid for forming the light-controlling layer was changed to 52 mass% liquid crystal compound, 3 mass% dichroic dye, 44 mass% photopolymerizable compound and polymerization initiator, and 1 mass% spacer, and the material of the first transparent electrode layer and the second transparent electrode layer was changed to a silver alloy.

[0081] Comparative Example 1 The ratio of each material in the coating liquid for forming the light-controlling layer was changed to 52% by mass of the liquid crystal compound, 0% by mass of the dichroic dye, 47% by mass of the photopolymerizable compound and polymerization initiator, and 1% by mass of the spacer, and the particle size of the spacer was changed to make the thickness of the light-controlling layer 22 μm. Except for this, the light-controlling sheet of Comparative Example 1 was obtained using the same materials and processes as in Example 1. In other words, the light-controlling sheet of Comparative Example 1 does not contain a dichroic dye.

[0082] Comparative Example 2 The light-control sheet of Comparative Example 2 was obtained using the same materials and processes as in Example 1, except that the proportions of each material in the coating liquid for forming the light-control layer were changed to 48 mass% liquid crystal compound, 1.5 mass% dichroic dye, 49.5 mass% photopolymerizable compound and polymerization initiator, and 1 mass% spacer.

[0083] (evaluation) For the light-adjusting sheets of each embodiment and each comparative example, the average infrared light transmittance in the opaque state and the total light transmittance of light in the visible region in each of the opaque state and the transparent state were measured. The average infrared light transmittance is the average transmittance of light with a wavelength of 780 nm or more and 2000 nm or less, and was measured using an infrared spectrometer. The total light transmittance was measured by a method conforming to JIS K 7361-1. The opaque state is a state in which the applied voltage is 0 V, and the transparent state is a state in which the applied voltage is 60 V.

[0084] In addition, in the laser irradiation process during the manufacture of the light-adjusting sheet of each example and each comparative example, a processing evaluation was performed by checking whether a nonconductive part could be formed only on the first transparent electrode layer of the first transparent electrode layer and the range of the laser scanning speed capable of forming a nonconductive part only on the first transparent electrode layer. In the processing evaluation, when a nonconductive part could be formed only on the first transparent electrode layer and the range of the laser scanning speed capable of the processing was wide, it was evaluated as particularly good "◎", when a nonconductive part could be formed only on the first transparent electrode layer and the range of the laser scanning speed capable of the processing was narrow, it was evaluated as good "○", and when a nonconductive part could not be formed only on the first transparent electrode layer, it was evaluated as poor "×". The range of the laser scanning speed when the evaluation was particularly good "◎" was 3000mm / s to 4500mm / s, and the range of the laser scanning speed when the evaluation was good "○" was 3000mm / s.

[0085] The composition of the light control layer, the thickness of the light control layer, and the material of the transparent electrode layer for each example and comparative example are shown in Table 1. Table 2 shows the average infrared light transmittance, total light transmittance, and processing evaluation for each example and comparative example.

[0086] [Table 1]

[0087] [Table 2]

[0088] As shown in Tables 1 and 2, in Examples 1 to 3 in which the average infrared light transmittance in the opaque state was 64% or less, the processing evaluation was good or particularly good, and it was possible to form a non-conductive portion only in the first transparent electrode layer. Furthermore, when the average infrared light transmittance was 60% or less, the processing evaluation was particularly good, and it was confirmed that the range of laser scanning speeds available for processing was expanded.

[0089] On the other hand, in Comparative Examples 1 and 2 in which the average infrared light transmittance exceeded 64%, the processing evaluation was poor, and it was not possible to form a non-conductive portion only in the first transparent electrode layer. Even when the light-control layer contains a dichroic dye, as in Comparative Example 2, it was confirmed that it was not possible to form a non-conductive portion only in the first transparent electrode layer when the average infrared light transmittance exceeded 64%. This suggests that in order to achieve an average infrared light transmittance of 64% or less, it is preferable for the light-control layer to contain 3 mass% or more of the dichroic dye.

[0090] As described above in the embodiments and examples, the light controlling sheet can provide the following effects. (1) The light-controlling layer 20 contains a dichroic dye 22P that has light absorption in the infrared region, and the average infrared light transmittance of the light-controlling sheet 10 and the laminated sheet 90 in an opaque state is 64% or less. With this configuration, infrared light is absorbed by the light-controlling layer, so that it is easy to form a non-conductive portion 35 in only one of the two transparent electrode layers 31, 32 by using an infrared laser. This prevents an increase in the number of wirings required to connect the transparent electrode layers 31, 32 to a power source, and prevents the layout of the wiring portion and the control of the input of the voltage signal from becoming complicated.

[0091] (2) By making the ratio of the dichroic dye 22P in the light-adjusting layer 20 1% by mass or more and 10% by mass or less, the difference in color between the transparent state and the opaque state of the light-adjusting sheet can be clearly recognized, and the precipitation of the dichroic dye and the increase in the manufacturing cost of the light-adjusting sheet can be suppressed. Furthermore, the light-adjusting layer 20 can easily obtain sufficient light absorption in the infrared region.

[0092] (3) If the color of the dichroic dye 22P is black, the insulating portion 61, which is a laser processing mark, is less noticeable in an opaque state. (4) Since the proportion of the transparent polymer layer 21 in the light-adjusting layer 20 is 20% by mass or more and 80% by mass or less, a domain is adequately secured in the transparent polymer layer 21, and a structure of the light-adjusting layer 20 in which the liquid crystal composition 22 is dispersed in the transparent polymer layer 21 is suitably formed.

[0093] (5) The material of the transparent electrode layers 31 and 32 includes indium tin oxide or a silver alloy. With the light control sheet 10 and the laminated sheet 90 having such a configuration, it is preferably possible to process only one of the two transparent electrode layers 31 and 32 using an infrared laser, as shown in the examples.

[0094] (6) The material of the transparent support layers 41 and 42 contains polyethylene terephthalate. With the light control sheet 10 and the laminated sheet 90 having such a configuration, it is preferably possible to process only one of the two transparent electrode layers 31 and 32 using an infrared laser, as shown in the examples.

[0095] (Modification) The above embodiment may be modified as follows. The following modifications may be combined with each other.

[0096] As long as the average infrared light transmittance of the light-adjusting sheet 10 and the laminate sheet 90 is 64% or less, and the light-adjusting sheet 10 is configured to be switched between a transparent state and an opaque state based on a change in the orientation state of the liquid crystal molecules due to the application of a driving voltage, the layer structure of the light-adjusting sheet 10 is not limited to the structure described in the above embodiment.

[0097] For example, the light-adjusting sheet may include an alignment layer that controls the alignment of liquid crystal molecules. The light-adjusting sheet may also include a functional layer having a desired function. The functional layer may be laminated on the transparent support layers 41, 42 and positioned at the outermost part of the light-adjusting sheet, or may be positioned between layers such as between the transparent electrode layers 31, 32 and the transparent support layers 41, 42. The functional layer may be, for example, a hard coat layer, an anti-blocking layer, a primer layer, a protective layer, an index matching layer, or the like. [Explanation of symbols]

[0098] 10. Light-adjusting sheet 20...Photochromic layer 21...Transparent polymer layer 21D…Domain 22...Liquid crystal composition 22L…Liquid crystal compound 22P…Dichroic pigment 23…Spacer 31,32...Transparent electrode layer 33...Conductive part 35...Non-conductive part 41,42...Transparent support layer 51,52...Wiring section 55...Control section 60…Light control section 61…Insulation section 90...Laminated sheet

Claims

1. a light-controlling layer including a transparent polymer layer including a plurality of domains and a liquid crystal composition filling the domains, the liquid crystal composition including a liquid crystal compound and a dichroic dye; a pair of transparent electrode layers, a first transparent electrode layer and a second transparent electrode layer, sandwiching the light control layer; A light-controlling sheet that changes the orientation of the liquid crystal compound and the dichroic dye in response to a change in the potential difference between the pair of transparent electrode layers, thereby switching from a colored opaque state to a transparent state, When viewed from a position facing the surface of the light-adjusting sheet, the first transparent electrode layer includes a non-conductive portion extending linearly and a conductive portion separated by the non-conductive portion, and a conductive portion of the second transparent electrode layer overlaps with each of the conductive portion and the non-conductive portion, The average transmittance of light in the infrared region through the light-adjusting sheet in the opaque state is 64% or less. Dimming sheet.

2. The ratio of the dichroic dye in the light-adjusting layer is 1% by mass or more and 10% by mass or less. The light controlling sheet according to claim 1 .

3. The proportion of the transparent polymer layer in the light-controlling layer is 20% by mass or more and 80% by mass or less. The light controlling sheet according to claim 1 .

4. The material of each of the first transparent electrode layer and the second transparent electrode layer includes indium tin oxide or a silver alloy. The light controlling sheet according to claim 1 .

5. a pair of transparent support layers sandwiching the light control layer and the pair of transparent electrode layers; The material of each of the pair of transparent support layers includes polyethylene terephthalate. The light controlling sheet according to claim 1 .

6. forming a laminated sheet including a transparent polymer layer including a plurality of domains, a light control layer including a liquid crystal composition filling the domains, the liquid crystal composition including a liquid crystal compound and a dichroic dye, and a pair of transparent electrode layers sandwiching the light control layer, the pair being a first transparent electrode layer and a second transparent electrode layer; irradiating the laminated sheet with an infrared laser from a side where the first transparent electrode layer is located with respect to the light control layer to form linear non-conductive portions and conductive portions separated by the non-conductive portions in the first transparent electrode layer; The average transmittance of the laminated sheet to light in the infrared region is 64% or less. A method for manufacturing light-controlling sheets.

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