Dimming sheet and method for manufacturing dimming sheet

Abstract

The light control sheet comprises: a light control layer containing a liquid crystal compound and a dichroic dye; and a pair of transparent electrode layers, i.e., a first transparent electrode layer and a second transparent electrode layer, which sandwich the dimming layer. When viewed from a position facing the surface of the dimming 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 in the second transparent electrode layer overlaps the conductive portion and the non-conductive portion, respectively. The average transmittance of light in the infrared region of the dimming sheet in the opaque state is 64% or less.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a light-adjustable sheet and a manufacturing method of a light-adjustable sheet. BACKGROUND

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

[0003] In order to improve the design or expand the function, a structure in which a light-adjustable sheet is divided into a plurality of regions and the transparent state and the opaque state can be switched in each region has been proposed (for example, refer to Patent Literature 1). For example, the light-adjustable sheet is divided into a plurality of regions by cutting or laser irradiation using a cutting device to locally insulate the transparent electrode layers.

[0004] PRIOR ART DOCUMENTS PATENT LITERATURE Patent Literature 1: Japanese Patent Application Publication No. 2018-60128 SUMMARY

[0005] PROBLEMS TO BE SOLVED BY THE INVENTION In a case where a light-adjustable sheet is divided into a plurality of regions using a cutting device, the transparent support layer located on the surface of the light-adjustable sheet is also cut along with the transparent electrode layers. Therefore, it is necessary to protect the surface of the cut light-adjustable sheet, and in addition, if the cut portion is rough, it can also cause the appearance of the light-adjustable sheet to deteriorate.

[0006] On the other hand, in a case where a light-adjustable sheet is divided into a plurality of regions by laser irradiation, the laser can transmit through the transparent support layer, and thus the cutting of the surface of the light-adjustable sheet can be avoided. However, since the laser also transmits through the light-adjustable layer, both of the pair of transparent electrode layers are insulated. Therefore, it is necessary to connect a wiring for applying a voltage to the transparent electrode layers sandwiching the light-adjustable layer for each region after division. Therefore, the number of wirings increases, and the manufacturing of the light-adjustable sheet or the control of voltage application becomes complicated.

[0007] MEANS FOR SOLVING THE PROBLEMS One embodiment of a light-adjustable sheet includes: a light-adjustable layer containing a transparent polymer layer and a liquid crystal composition, the transparent polymer layer containing a plurality of domains, the liquid crystal composition filling the domains and containing a liquid crystal compound and a dichroic dye; and a pair of transparent electrode layers, i.e., a first transparent electrode layer and a second transparent electrode layer, sandwiching the light-adjustable layer, The alignment of the liquid crystal compound and the dichroic pigment is changed in accordance with a change in the potential difference between the pair of transparent electrode layers, whereby the colored opaque state is switched to the transparent state, wherein, when viewed from a position facing a surface of the light control sheet, the first transparent electrode layer includes a non-conductive portion extending in a linear shape and a conductive portion separated by the non-conductive portion, the portion having conductivity in the second transparent electrode layer overlaps with the conductive portion and the non-conductive portion, respectively, and the average transmittance of light in an infrared region of the light control sheet in the opaque state is 64% or less.

[0008] One embodiment of a method for manufacturing a light control sheet includes the following steps: forming a layered sheet having a light control layer including a transparent polymer layer including a plurality of domains and a liquid crystal composition filling the domains and including a liquid crystal compound and a dichroic pigment, and a pair of transparent electrode layers, i.e., a first transparent electrode layer and a second transparent electrode layer, sandwiching the light control layer; and for the layered sheet, irradiating an infrared laser from a side on which the first transparent electrode layer is positioned with respect to the light control layer, and forming a linear non-conductive portion and a conductive portion separated by the non-conductive portion in the first transparent electrode layer, wherein the average transmittance of light in an infrared region of the layered sheet is 64% or less. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is a view showing a cross-sectional structure of a light control sheet according to one embodiment.

[0010] Figure 2 is a view showing a planar structure of the light control sheet according to the above embodiment.

[0011] Figure 3 is a view showing a part of the cross-sectional structure of the light control sheet according to the above embodiment in an enlarged manner.

[0012] Figure 4 is a view showing a structure of the light control layer of the light control sheet according to the above embodiment.

[0013] Figure 5 is a view showing a method for manufacturing the light control sheet according to the above embodiment. DETAILED DESCRIPTION

[0014] REFERENCE Figures 1-5 One embodiment of a light control sheet and a method for manufacturing the same will be described.

[0015] [Layer Configuration of Light Control Sheet] REFERENCE Figure 1The layer composition of the dimming sheet is explained. For example... Figure 1 As shown, the dimming sheet 10 includes a dimming 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 dimming 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 to the dimming layer 20 relative 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 to the dimming layer 20 relative to the second transparent electrode layer 32.

[0016] The dimming layer 20 comprises a transparent polymer layer having multiple pores and a liquid crystal composition held within the pores. The dimming layer 20 may have, for example, a polymer-dispersed liquid crystal or a polymer network liquid crystal structure.

[0017] The first transparent electrode layer 31 and the second transparent electrode layer 32 are both conductive and transparent to visible light. The materials of the transparent electrode layers 31 and 32 are, for example, indium tin oxide, fluorine-doped tin oxide, tin oxide, zinc oxide, carbon nanotubes, poly(3,4-ethylenedioxythiophene), silver, silver alloys, etc.

[0018] The first transparent support layer 41 and the second transparent support layer 42 are both light-transparent substrates to the visible area. The materials of the transparent support layers 41 and 42 are, for example, synthetic resins or inorganic compounds. Synthetic resins include, for example, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyacrylates such as polymethyl methacrylate, polycarbonate, and polyolefins. Inorganic compounds include, for example, silicon dioxide, silicon oxynitride, and silicon nitride.

[0019] The dimming sheet 10 has a sheet region RS, a first end region RE1, and a second end region RE2. The dimming layer 20 and the layers that hold the dimming layer 20 are located in the sheet region RS. In other words, the sheet region RS is the region where the dimming layer 20 is held between a pair of transparent electrode layers 31 and 32.

[0020] The first end region RE1 and the second end region RE2 are located at the ends of the dimming sheet 10. The first transparent support layer 41 and the first transparent electrode layer 31 extend from the sheet region RS toward the first end region RE1. That is, in the first end region RE1, the first transparent electrode layer 31 is exposed from the dimming layer 20, the second transparent electrode layer 32, and the second transparent support layer 42. Moreover, a first wiring portion 51 for electrically connecting the first transparent electrode layer 31 to a power source is connected to the surface of the exposed first transparent electrode layer 31.

[0021] The second transparent support layer 42 and the second transparent electrode layer 32 extend from the sheet region RS toward the second end region RE2. That is, in the second end region RE2, the second transparent electrode layer 32 is exposed from the dimming layer 20, the first transparent electrode layer 31, and the first transparent support layer 41. Moreover, a second wiring portion 52 for electrically connecting the second transparent electrode layer 32 to a power source is connected to the surface of the exposed second transparent electrode layer 32.

[0022] The first wiring section 51 and the second wiring section 52 each, for example, include a conductive adhesive layer and a wiring substrate. The conductive adhesive layer is formed, for example, of anisotropic conductive film (ACF), anisotropic conductive paste (ACP), isotropic conductive film (ICF), or isotropic conductive paste (ICP). The wiring substrate is, for example, a flexible printed circuit board (FPC). Alternatively, the first wiring section 51 and the second wiring section 52 may each have a structure in which a conductive material such as a conductive strip is bonded to a wire by soldering.

[0023] The transparent electrode layers 31 and 32 are electrically connected to the control unit 55 via wiring sections 51 and 52. The control unit 55 applies an alternating current voltage, i.e., a driving voltage, to the transparent electrode layers 31 and 32 through the wiring sections 51 and 52 to change the orientation state of the liquid crystal compound. The dimming sheet 10, the control unit 55, and the wiring sections 51 and 52 constitute a dimming device.

[0024] Furthermore, the dimming sheet 10 is adhered to a transparent substrate, which is the object to be installed. The transparent substrate is a glass substrate or a resin substrate. Examples of transparent substrates include window glass installed on moving bodies such as vehicles or aircraft, window glass installed in buildings, and partitions installed in vehicle interiors or rooms. The surface on which the dimming sheet 10 is adhered can be flat or curved. Alternatively, the dimming sheet 10 can also be sandwiched between two transparent substrates.

[0025] [The planar structure of dimming sheets] Reference Figure 2 as well as Figure 3 The configuration of RS, RE1, RE2 regions and wiring sections 51 and 52 in the dimming sheet 10 is described. Figure 2 In this text, for ease of understanding, RS markers are used to represent the sheet material area.

[0026] like Figure 2As shown, the sheet region RS has multiple dimming sections 60 and one or more insulating sections 61. When viewed from a position facing the surface of the dimming sheet 10, the insulating section 61 extends in a linear shape, separating adjacent dimming sections 60. In other words, the sheet region RS is divided into multiple dimming sections 60 by the insulating section 61.

[0027] exist Figure 2 The image shows an example where the dimming section 60 and the insulating section 61 extend in one direction, and the dimming section 60 is divided into three strips by two insulating sections 61. However, this is not a limitation; the number or shape of the dimming section 60 and the insulating section 61 can be arbitrary as long as the dimming section 60 is divided by linear insulating sections 61.

[0028] Figure 3 The diagram shows the cross-sectional structure near 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 the portion that loses its conductivity due to laser irradiation damaging or modifying the first transparent electrode layer 31. In other words, the non-conductive portion 35 is a laser processing mark that extends linearly when viewed from a position facing the surface of the dimming sheet 10. The conductive portion 33 is the portion that is conductive without being irradiated by the laser.

[0029] On the other hand, the second transparent electrode layer 32 does not have non-conductive portions. In other words, the entire second transparent electrode layer 32 is a conductive portion 34.

[0030] In the sheet region RS, when viewed from a position facing the surface of the dimming sheet 10, the portion containing the conductive part 33 is the dimming part 60, and the portion containing the non-conductive part 35 is the insulating part 61. That is, in the dimming part 60, both the first transparent electrode layer 31 and the second transparent electrode layer 32 are conductive, while in the insulating part 61, the first transparent electrode layer 31 is not conductive, and the second transparent electrode layer 32 is conductive. The conductive parts 33 of the first transparent electrode layers 31 in adjacent dimming parts 60 are insulated from each other by the presence of non-conductive parts 35 acting as insulating parts 61 between them.

[0031] return Figure 2 The first end region RE1 has a first connecting portion 70 and an end insulating portion 71. The first connecting 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 at the first connecting portion 70. The end insulating portion 71 extends continuously in a linear form from the insulating portion 61 of the sheet region RS. The non-conductive portion 35 of the first transparent electrode layer 31 is located at the end insulating portion 71. The conductive portions 33 of the first transparent electrode layers 31 in adjacent first connecting portions 70 are insulated from each other by the presence of non-conductive portions 35 as end insulating portions 71 between them.

[0032] Thus, for each dimming unit 60, a first connection portion 70 that is conductive to the dimming unit 60 is provided on the first transparent electrode layer 31, and adjacent first connection portions 70 are separated by end insulating portions 71. Furthermore, a first wiring portion 51 is connected to the first transparent electrode layer 31 of each first connection portion 70.

[0033] The second end region RE2 does not have an insulating portion. That is, the second transparent electrode layer 32 contained in the sheet region RS and the second end region RE2 is entirely a conductive film. The second end region RE2 has a second connection portion 80. Moreover, a second wiring portion 52 is connected to the second transparent electrode layer 32 of the second connection portion 80. Thus, one second wiring portion 52 is connected to the second end region RE2.

[0034] In addition, Figure 2 The diagram shows the arrangement of the first end region RE1 and the second end region RE2 along the opposing edges of the dimming sheet 10, but the positional relationship between the first end region RE1 and the second end region RE2 can be arbitrarily set. In other words, the first connecting portion 70 and the second connecting portion 80 can be arranged along the opposing edges of the dimming sheet 10, or they can have a different arrangement.

[0035] [Composition of the dimming layer] Reference Figure 4 This explains the detailed composition of the dimming layer 20. Figure 4 This diagram schematically shows the overlapping portion of the dimming layer 20 and the transparent electrode layers 31 and 32 in the cross-sectional structure of the dimming sheet 10, emphasizing the composition of the dimming layer 20.

[0036] The dimming layer 20 comprises a transparent polymer layer 21, a liquid crystal composition 22, and spacers 23. The transparent polymer layer 21 is a cured product of a photopolymerizable compound. The transparent polymer layer 21 is divided into a plurality of dispersed domains 21D within itself. In other words, the domains 21D are voids. The shape of the domains 21D is, for example, approximately spherical, approximately ellipsoidal, or irregular. The spaces within the domains 21D are filled by the liquid crystal composition 22.

[0037] The proportion of the transparent polymer layer 21 in the dimming layer 20 is preferably 20% by mass or more and 80% by mass or less, more preferably 30% by mass or more and 60% by mass or less. If the proportion of the transparent polymer layer 21 is within the above range, the domain 21D can be adequately ensured. Within the above range, the larger the proportion of the transparent polymer layer 21, the more the mechanical strength of the transparent polymer layer 21 can be improved, and the smaller the proportion of the transparent polymer layer 21, the more the driving voltage of the dimming sheet 10 can be reduced.

[0038] The photopolymerizable compound of the transparent polymer layer 21 can be either an ultraviolet-curable compound or an electron beam-curable compound. The photopolymerizable compound is compatible with the liquid crystal composition 22. When the photopolymerizable compound is an ultraviolet-curable compound, the size controllability of the domain 21D is improved. The photopolymerizable compound can be a single polymerizable compound or a combination of two or more polymerizable compounds.

[0039] One example of a UV-curable compound is that it contains polymerizable unsaturated bonds at the ends of its molecular structure. Another example of a UV-curable compound is that it contains polymerizable unsaturated bonds outside the ends of its molecular structure. Examples of UV-curable compounds include acrylate compounds, methacrylate compounds, thiols, styrene compounds, and oligomers of these compounds. Acrylate compounds include diacrylate compounds, triacrylate compounds, and tetraacrylate compounds. Examples of acrylate compounds are butyl ethyl acrylate, ethylhexyl acrylate, and cyclohexyl acrylate. Methacrylate compounds include dimethacrylate compounds, trimethacrylate compounds, and tetramethacrylate compounds. Examples of methacrylate compounds are N,N-dimethylaminoethyl methacrylate, phenoxyethyl methacrylate, methoxyethyl methacrylate, and tetrahydrofurfuryl methacrylate. Examples of thiols are 1,3-propanedithiol and 1,6-hexanedithiol. Examples of styrene compounds are styrene and methylstyrene.

[0040] The liquid crystal composition 22 comprises a liquid crystal compound 22L and a dichroic pigment 22P. Furthermore, the liquid crystal composition 22 may further contain viscosity reducers, defoamers, antioxidants, weathering agents, etc. Examples of weathering agents include ultraviolet absorbers or light stabilizers.

[0041] Liquid crystal compound 22L is a non-polymerizable compound. The dielectric constant along the long axis of liquid crystal compound 22L is higher than that along the short axis. That is, liquid crystal compound 22L exhibits positive dielectric anisotropy.

[0042] Liquid crystal compound 22L is, for example, a Schiff base-based, azo-based, azo oxide-based, biphenyl-based, terphenyl-based, benzoic acid ester-based, diphenylacetylene-based, pyrimidine-based, pyridazine-based, cyclohexane-based, phenylcyclohexane-based, biphenylcyclohexane-based, dicyanophenylene-based, naphthalene-based, and dioxane-based compounds. Liquid crystal compound 22L can be a single liquid crystal compound or a combination of two or more liquid crystal compounds.

[0043] Dichroic pigment 22P has an elongated molecular shape, with greater absorbance in the visible region along its long axis than along its short axis. Dichroic pigment 22P displays a predetermined color when its long axis is approximately orthogonal to the incident direction of light. The color exhibited by dichroic pigment 22P is, for example, black or near-black. The color display of dichroic pigment 22P is driven by a host-guest pattern primarily composed of liquid crystal compound 22L.

[0044] Furthermore, the dichroic pigment 22P absorbs light in the infrared region. Infrared light refers to light with wavelengths above 780 nm and below 2000 nm.

[0045] Dichroic pigment 22P is, for example, a polyiodine, azo compound, anthraquinone compound, naphthoquinone compound, methylimine compound, tetrazine compound, quinoline compound, cyanine compound, perylene compound, or dioxazine compound. Dichroic pigment 22P can be a single pigment or a combination of two or more pigments. From the viewpoint of improving lightfastness and dichroic ratio, dichroic pigment 22P is preferably selected from at least one of azo compound and anthraquinone compound, more preferably an azo compound.

[0046] The proportion of dichroic pigment 22P in the dimming layer 20 is preferably 1% by mass or more and 10% by mass or less, more preferably 2% by mass or more and 5% by mass or less. With a proportion of dichroic pigment 22P of 1% by mass or more, the color difference between the transparent and opaque states of the dimming sheet 10 can be easily and clearly identified. Furthermore, the absorption of light in the infrared region of the dimming layer 20 can be fully and easily obtained. With a proportion of dichroic pigment 22P of 10% by mass or less, the precipitation of particles formed by the aggregation of dichroic pigment 22P can be suppressed.

[0047] Spacers 23 are dispersed throughout the transparent polymer layer 21. The spacers 23 define the thickness of the dimming layer 20 around their periphery, thereby homogenizing the thickness of the dimming layer 20. The spacers 23 can be bead spacers or photosensitive spacers formed by exposure and development of a photoresist. Spacers 23 can be colorless or colored transparent, provided they are transparent. Preferably, the color exhibited by the colored transparent spacers 23 is the same as the color exhibited by the dichroic pigment 22P.

[0048] Since the thickness of the dimming layer 20 is substantially the same as the size of the spacers 23, the thickness of the dimming layer 20 can be controlled by changing the average particle size of the spacers 23. For example, the average particle size of the spacers 23, measured in terms of median particle size D50, is 10 μm or more and 30 μm or less. In this case, the thickness of the dimming layer 20 is 10 μm or more and 30 μm or less.

[0049] [Electrical Configuration of the Dimming Device] Voltage signals input from the control unit 55 to each first wiring unit 51 are input to the first transparent electrode layer 31 of the dimming unit 60, which is connected to the first connection unit 70 connected to the first wiring unit 51, according to each first wiring unit 51. That is, voltage signals are input to the first transparent electrode layer 31 of each dimming unit 60 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, when the control unit 55 inputs a common voltage signal to the second transparent electrode layer 32 of each dimming unit 60, it controls the input of the voltage signal to the first transparent electrode layer 31 according to each dimming unit 60, thereby enabling the application of the driving voltage to the dimming unit 60 according to each dimming unit 60.

[0052] The dimming unit 60 switches between a transparent state and an opaque state based on changes in the orientation state of the liquid crystal composition 22. In the opaque state, the dimming sheet 10 is colored; in the transparent state, the dimming sheet 10 is colorless or nearly colorless and transparent. In the opaque state, the total light transmittance of the dimming sheet 10 becomes lower than in the transparent state, and the haze of the dimming sheet 10 becomes higher than in the transparent state.

[0053] When no driving voltage is applied, the orientation of the long axis of the liquid crystal compound 22L and the dichroic pigment 22P is disordered. Therefore, light incident on the dimming section 60 is scattered in all directions within the dimming layer 20. Furthermore, since the orientation of the long axis of the dichroic pigment 22P is disordered, at least a portion of the dichroic pigment 22P displays color. Therefore, when no driving voltage is applied, the dimming section 60 becomes opaque and appears colored.

[0054] When the dielectric constant of the liquid crystal compound 22L is positively anisotropic, when a driving voltage is applied, the liquid crystal compound 22L and the dichroic pigment 22P align with their long axes along the direction of the electric field. That is, the orientation of the liquid crystal compound 22L and the dichroic pigment 22P changes such that their long axes are aligned with the thickness direction of the dimming layer 20. As a result, light scattering in the dimming layer 20 and color rendering of the dichroic pigment 22P are suppressed, and light easily passes through the dimming section 60. Therefore, when a driving voltage is applied, the dimming section 60 becomes transparent.

[0055] [Characteristics of dimming sheets] The optical properties of the dimming sheet 10 will be explained. The dimming sheet 10 of this embodiment contains a dichroic pigment 22P that absorbs light in the infrared region. Therefore, the dimming sheet 10 in its opaque state has absorption properties for light in the infrared region. In other words, in the opaque dimming sheet 10, the transmittance of light in the infrared region is suppressed. Specifically, the average transmittance of light in the infrared region of the opaque dimming sheet 10 is 64% or less.

[0056] The aforementioned average infrared light transmittance can be adjusted by the type or proportion of dichroic pigments 22P contained in the dimming layer 20. For example, when a dimming sheet 10 that appears black in an opaque state is constructed by mixing and using multiple dichroic pigments 22P, the average infrared light transmittance can be reduced by increasing the proportion of dichroic pigments 22P that exhibit high absorption in the long wavelength region of the visible area.

[0057] Furthermore, in the opaque dimming sheet 10, the total light transmittance in the visible area is preferably 20% or less, more preferably 5% or less. On the other hand, in the transparent dimming sheet 10, the total light transmittance in the visible area is preferably 40% or more, more preferably 50% or more. Thus, the difference in transparency between the transparent and opaque states can be clearly obtained.

[0058] [Manufacturing method of dimming sheet] Reference Figure 5 The manufacturing method of the dimming sheet 10 is explained.

[0059] First, a laminate comprising a dimming layer 20, transparent electrode layers 31 and 32, and transparent support layers 41 and 42 is formed. At this time, the first transparent electrode layer 31 is a conductive film without the non-conductive portion 35 formed thereon.

[0060] In detail, firstly, a first transparent support layer 41 with a first transparent electrode layer 31 stacked on top of a second transparent support layer 42 with a second transparent electrode layer 32 stacked on top of it is prepared. The transparent electrode layers 31 and 32 are formed, for example, by a known film formation method such as sputtering.

[0061] Next, a coating for forming the dimming layer 20 is formed between the first transparent electrode layer 31 and the second transparent electrode layer 32. The coating comprises a photopolymerizable compound, a liquid crystal compound 22L, a dichroic pigment 22P, and a polymerization initiator for initiating the polymerization of the photopolymerizable compound. Examples of polymerization initiators include diketone compounds, acetophenone compounds, benzophenone compounds, thioxanone compounds, oxime ester compounds, etc. The coating may contain only a single type of polymerization initiator or multiple types of polymerization initiators.

[0062] In addition, spacer 23 may be included in the coating liquid used to form the coating film, or it may be dispersed in the coating film during the formation of the coating film.

[0063] Irradiating the laminated body holding the coating with light causes the photopolymerizable compound to polymerize, thereby causing phase separation of the liquid crystal composition 22 and forming the dimming layer 20. The light that polymerizes the photopolymerizable compound is ultraviolet light or an electron beam. The light that polymerizes the photopolymerizable compound can irradiate towards the first transparent support layer 41, or towards the second transparent support layer 42, or towards both the first transparent support layer 41 and the second transparent support layer 42.

[0064] From the laminate obtained above, the laminated sheet 90, comprising the dimming layer 20, transparent electrode layers 31, 32, and transparent support layers 41, 42, is cut into the desired shape of the dimming sheet 10. In the laminated sheet 90, the orientation of the liquid crystal compound 22L and the dichroic pigment 22P contained in the dimming layer 20 is disordered, and the laminated sheet 90 is opaque. Furthermore, the average infrared light transmittance of the laminated sheet 90 is also 64% or less, similar to that of the opaque dimming sheet 10.

[0065] like Figure 5 As shown, laser La is irradiated onto the laminated sheet 90. Specifically, the laser irradiation unit 100 of the laser device is positioned opposite the first transparent support layer 41, and laser La irradiates the area of ​​the laminated sheet 90 that becomes the insulating part 61, 71 from the side of the first transparent electrode layer 31 opposite to the dimming layer 20.

[0066] The laser wavelength is in the infrared region. For example, the laser wavelength is preferably above 1000 nm and below 1200 nm. The laser medium is not particularly limited. For example, Nd:YAG lasers, Nd:YVO4 lasers, CO2 lasers, semiconductor lasers, etc., can be used.

[0067] Laser La, irradiating the laminated sheet 90, passes through the first transparent support layer 41 and enters the first transparent electrode layer 31. As a result, the first transparent electrode layer 31 is damaged or modified and loses its conductivity, forming a non-conductive portion 35.

[0068] Furthermore, a portion of the laser La that enters the first transparent electrode layer 31 enters the dimming layer 20. Here, the dimming layer 20 has light absorption properties due to the infrared region containing the dichroic pigment 22P. Therefore, the laser La that enters the dimming layer 20 is absorbed by the dimming layer 20. As a result, it is possible to suppress the laser La from passing through the dimming layer 20 into the second transparent electrode layer 32. Consequently, it is possible to suppress the formation of non-conductive portions in the second transparent electrode layer 32, and it is possible to appropriately form an insulating portion 61 in which only the first transparent electrode layer 31 loses its conductivity.

[0069] Typically, the absorption spectrum of light originating from the infrared region of the dichroic pigment 22P does not have a steep peak only at a specific wavelength in the infrared region. If the average infrared transmittance of the laminated sheet 90 decreases, the transmittance decreases throughout the entire infrared region. If the average infrared transmittance of the laminated sheet 90 is below 64%, it is possible to appropriately suppress the laser La of the infrared wavelength from reaching the second transparent electrode layer 32 and thus process the second transparent electrode layer 32.

[0070] Furthermore, if the average infrared light transmittance of the laminated sheet 90 is below 60%, the laser La can be more effectively suppressed from passing through the dimming layer 20 into the second transparent electrode layer 32.

[0071] In addition, the absorption of light from the infrared region of the dichroic pigment 22P increases in the wavelength range of 1000nm to 1500nm. Therefore, if a laser La with a wavelength of 1000nm or higher and 1200nm or lower is used, the laser La can be more precisely suppressed from passing through the dimming layer 20 into the second transparent electrode layer 32.

[0072] After irradiation with laser La, the dimming layer 20, the second transparent electrode layer 32, and the second transparent support layer 42 are removed near one end of the laminated sheet 90, thereby forming a first end region RE1. Additionally, the dimming layer 20, the first transparent electrode layer 31, and the first transparent support layer 41 are removed near the other end of the laminated sheet 90, thereby forming a second end region RE2. Along with the formation of the first end region RE1 and the second end region RE2, a sheet region RS is formed.

[0073] From the above, a dimming sheet 10 is formed. Then, a first wiring portion 51 is connected to each first connection portion 70 in the first end region RE1, and a second wiring portion 52 is connected to the second connection portion 80 in the second end region RE2.

[0074] In the above manufacturing method, since the dimming layer 20 absorbs the laser, it is easy to form a non-conductive portion 35 only in the first transparent electrode layer 31. Therefore, in the dimming sheet 10, a voltage signal can be input to the second transparent electrode layer 32 as a whole from a second wiring portion 52. Thus, compared to the case where the first transparent electrode layer 31 and the second transparent electrode layer 32 are insulated from each other for each dimming unit 60, and wiring portions are provided in each transparent electrode layer 31, 32, i.e., where a separate voltage signal is input to the second transparent electrode layer 32 of each dimming unit 60, it is possible to prevent the arrangement of the wiring portions or the input control of the voltage signal from becoming complicated.

[0075] Furthermore, even when the dimming layer 20 does not absorb laser light, it is impossible to form a non-conductive portion only on one side of the transparent electrode layer by controlling the laser irradiation conditions. However, in this case, precise control of conditions such as the laser focus, output power, or scanning speed is required. In contrast, according to this embodiment, since the laser light is absorbed by the dimming layer 20, there is a margin for error in controlling the laser irradiation conditions, thereby reducing the burden required for manufacturing the dimming sheet 10.

[0076] [Example] The above-described dimming sheet will be described using specific embodiments and comparative examples.

[0077] (Example 1) A liquid crystal compound, a dichroic pigment, a photopolymerizable compound, and a polymerization initiator are mixed to generate a coating solution for forming a dimming layer. Details of the materials are described below. Furthermore, regarding the proportions of each material in the coating solution, the liquid crystal compound is 51% by mass, the dichroic pigment is 4% by mass, the photopolymerizable compound and polymerization initiator are 44% by mass, and the spacer is 1% by mass.

[0078] Liquid crystal compounds: cyanobiphenyl compounds • Dichroic pigment: Black dichroic pigment (YH-428, manufactured by Mitsui Chemicals Fine Co., Ltd.) • Photopolymerizable compounds (UV-curable compounds): A mixture of isobornyl acrylate, pentaerythritol triacrylate, and urethane acrylate. • Polymerization initiator: 1-hydroxycyclohexylphenyl ketone (Irgacure 184, manufactured by BASF Japan) • Spacer: Black spherical particles made of polymethyl methacrylate (particle size: 25 μm) A first sheet is fabricated as a laminate of the first transparent support layer and the first transparent electrode layer by sputtering to form a first transparent electrode layer. Similarly, a second sheet is fabricated as a laminate of the second transparent support layer and the second transparent electrode layer by sputtering to form a second transparent electrode layer. The first and second transparent support layers are made of polyethylene terephthalate and have a thickness of 125 μm. The first and second transparent electrode layers are made of indium tin oxide (ITO) and have a thickness of 30 nm.

[0079] A coating film is formed on a first transparent electrode layer by applying the above-mentioned coating liquid to a first sheet. The thickness of the coating film is 25 μm. Then, a second sheet is laminated onto the first sheet with the coating film formed by lamination to obtain a laminate of the first sheet, the coating film and the second sheet.

[0080] Next, a dimming layer is formed by irradiating the first transparent support layer of the aforementioned laminate with 365 nm ultraviolet light. The intensity of the ultraviolet light is 7.2 mW / cm². 2 The ultraviolet light irradiation time is 120 seconds. This results in a laminated sheet having a dimming layer, a pair of transparent electrode layers, and a pair of transparent support layers.

[0081] For the aforementioned laminated sheet, a laser is irradiated from the side of the first transparent support layer opposite to the dimming layer, forming a non-conductive portion on the first transparent electrode layer. The laser irradiation conditions are as follows.

[0082] Type: IR semiconductor laser Wavelength: 1064nm • Spot diameter: 30μm Thus, a dimming sheet of Embodiment 1 having multiple dimming sections divided by insulating parts was obtained.

[0083] (Example 2) The proportions of the materials in the coating liquid used to form the dimming layer were changed to 52% by mass of liquid crystal compound, 3% by mass of dichroic pigment, 44% by mass of photopolymerizable compound and polymerization initiator, and 1% by mass of spacer. Otherwise, the dimming sheet of Example 2 was obtained by using the same materials and processes as in Example 1.

[0084] (Example 3) The proportions of the materials in the coating liquid used to form the dimming layer were changed to 52% by mass of liquid crystal compound, 3% by mass of dichroic pigment, 44% by mass of photopolymerizable compound and polymerization initiator, and 1% by mass of spacer. The materials of the first transparent electrode layer and the second transparent electrode layer were changed to silver alloy. Otherwise, the dimming sheet of Example 3 was obtained by using the same materials and processes as in Example 1.

[0085] (Comparative Example 1) The proportions of the materials in the coating used to form the dimming layer were changed to 52% by mass of liquid crystal compound, 0% by mass of dichroic pigment, 47% by mass of photopolymerizable compound and polymerization initiator, and 1% by mass of spacer. The particle size of the spacer was also changed to make the thickness of the dimming layer 22 μm. Otherwise, the dimming sheet of Comparative Example 1 was obtained using the same materials and processes as in Example 1. That is, the dimming sheet of Comparative Example 1 does not contain dichroic pigment.

[0086] (Comparative Example 2) The proportions of the materials in the coating liquid used to form the dimming layer were changed to 48% by mass of liquid crystal compound, 1.5% by mass of dichroic pigment, 49.5% by mass of photopolymerizable compound and polymerization initiator, and 1% by mass of spacer. Otherwise, the dimming sheet of Comparative Example 2 was obtained using the same materials and processes as in Example 1.

[0087] (evaluate) For the dimming sheets of each embodiment and comparative example, the average infrared transmittance in the opaque state and the total light transmittance in the visible region in both the opaque and transparent states were measured. The average infrared transmittance was the average transmittance of light with wavelengths of 780 nm and 2000 nm, measured using an infrared spectrometer. The total light transmittance was measured according to the method of JIS K 7361-1. The opaque state was defined as having an applied voltage of 0 V, and the transparent state as having an applied voltage of 60 V.

[0088] Furthermore, during the laser irradiation process in the manufacturing of the dimming sheet in each embodiment and comparative example, a processing evaluation was conducted to determine whether a non-conductive portion was formed only in the first transparent electrode layer and the second transparent electrode layer, and the range of laser scanning speeds that enabled the formation of a non-conductive portion only in the first transparent electrode layer. In the processing evaluation, a wide range of laser scanning speeds that enabled the formation of a non-conductive portion only in the first transparent electrode layer was designated as "particularly good" (A); a narrow range of laser scanning speeds that enabled the formation of a non-conductive portion only in the first transparent electrode layer was designated as "good" (B); and a situation where a non-conductive portion could not be formed only in the first transparent electrode layer was designated as "unfavorable" (C). The range of laser scanning speeds for "particularly good" (A) was 3000 mm / s to 4500 mm / s, and the range of laser scanning speeds for "good" (B) was 3000 mm / s.

[0089] Table 1 shows the composition of the dimming layer, the thickness of the dimming layer, and the material of the transparent electrode layer for each embodiment and comparative example. Table 2 shows the average infrared light transmittance, total light transmittance, and processing evaluation for each embodiment and comparative example.

[0090] As shown in Tables 1 and 2, in Examples 1 to 3 where the average infrared light transmittance in the opaque state is 64% or less, the processing evaluation is good or particularly good, and non-conductive portions can be formed only in the first transparent electrode layer. Furthermore, it was confirmed that if the average infrared light transmittance is 60% or less, the processing evaluation is particularly good, and the range of scanning speeds of lasers that can be used for processing is expanded.

[0091] On the other hand, in Comparative Examples 1 and 2, where the average infrared light transmittance exceeded 64%, the processing was evaluated as poor, and it was impossible to form a non-conductive portion only in the first transparent electrode layer. As confirmed in Comparative Example 2, even when the dimming layer contains a dichroic pigment, if the average infrared light transmittance exceeds 64%, it is impossible to form a non-conductive portion only in the first transparent electrode layer. Furthermore, it is shown that in order to make the average infrared light transmittance less than 64%, it is preferable that the dimming layer contains more than 3% by mass of a dichroic pigment.

[0092] As described above in the embodiments and examples, the following effects can be obtained from the dimming sheet.

[0093] (1) The dimming layer 20 contains a dichroic pigment 22P that absorbs light in the infrared region, and the average infrared light transmittance of the opaque dimming sheet 10 and the laminated sheet 90 is 64% or less. With this configuration, infrared light is absorbed by the dimming layer, and therefore, by using an infrared laser, a non-conductive portion 35 can be easily formed only on one of the two transparent electrode layers 31, 32. Therefore, it is possible to suppress the increase in the number of wires required to connect the transparent electrode layers 31, 32 to the power supply, and to prevent the configuration of the wiring portion or the input control of the voltage signal from becoming complicated.

[0094] (2) By ensuring that the proportion of dichroic pigment 22P in the dimming layer 20 is 1% by mass or more and 10% by mass or less, the color difference between the transparent and opaque states of the dimming sheet can be easily and clearly identified. In addition, the precipitation of dichroic pigment or the increase in manufacturing cost of the dimming sheet can be suppressed. Furthermore, the absorption of light in the infrared region of the dimming layer 20 can be easily and fully obtained.

[0095] (3) If the color presented by the dichroic pigment 22P is black, the insulating part 61, which is a laser processing mark, can be suppressed from being conspicuous in the opaque state.

[0096] (4) By making the proportion of transparent polymer layer 21 in dimming layer 20 20% by mass or more and 80% by mass or less, domains can be adequately ensured in transparent polymer layer 21, and a structure in which liquid crystal composition 22 is dispersed in transparent polymer layer 21 can be appropriately formed.

[0097] (5) The transparent electrode layers 31 and 32 are made of indium tin oxide or silver alloy. If the dimming sheet 10 and the laminated sheet 90 are configured in this way, then as shown in the embodiment, it is preferable to use an infrared laser to process only one of the two transparent electrode layers 31 and 32.

[0098] (6) The transparent support layers 41 and 42 are made of polyethylene terephthalate. If the dimming sheet 10 and the laminated sheet 90 are configured in this way, then as shown in the embodiment, it is preferable to use an infrared laser to process only one of the two transparent electrode layers 31 and 32.

[0099] (Modified example) The above-described embodiments can also be implemented by modification as follows. Furthermore, the following variations can also be combined with each other.

[0100] • As long as the average infrared light transmittance of the dimming sheet 10 and the laminated sheet 90 is 64% or less, and the transparent state and opaque state of the dimming sheet 10 are switched based on the change in the orientation state of the liquid crystal compound caused by the application of the driving voltage, the layer configuration of the dimming sheet 10 is not limited to the configuration described in the above embodiments.

[0101] For example, the dimming sheet can have an alignment layer that controls the orientation of the liquid crystal compound. Additionally, the dimming sheet can also have a functional layer with the desired function. The functional layer can be stacked on the outermost layer of the transparent support layers 41, 42, or located between the transparent electrode layers 31, 32 and the transparent support layers 41, 42, etc. Examples of functional layers include hard coatings, anti-blocking layers, primer layers, protective layers, and refractive index matching layers.

Claims

1. A light-adjustable sheet comprising: a light-adjustable layer including a transparent polymer layer including a plurality of domains and a liquid crystal composition filling the domains and including a liquid crystal compound and a dichroic dye; and a pair of transparent electrode layers, i.e., a first transparent electrode layer and a second transparent electrode layer, sandwiching the light-adjustable layer, the orientation of the liquid crystal compound and the dichroic dye being changed in accordance with a change in potential difference between the pair of transparent electrode layers, whereby a colored opaque state is switched to a transparent state, the first transparent electrode layer including a non-conductive portion extending in a linear shape and a conductive portion separated by the non-conductive portion when viewed from a position facing a surface of the light-adjustable sheet, a portion having conductivity in the second transparent electrode layer overlapping the conductive portion and the non-conductive portion, respectively, the average transmittance of light in an infrared region of the light-adjustable sheet in the opaque state being 64% or less. The proportion of the dichroic dye in the light-adjustable layer is 1% by mass or more and 10% by mass or less. The proportion of the transparent polymer layer in the light-adjustable layer is 20% by mass or more and 80% by mass or less. The material of each of the first transparent electrode layer and the second transparent electrode layer includes indium tin oxide or a silver alloy. wherein 5. The light-adjustable sheet according to claim 1, comprising a pair of transparent support layers sandwiching the light-adjustable layer and the pair of transparent electrode layers, the material of each of the pair of transparent support layers including polyethylene terephthalate.

6. A method for manufacturing a light-adjustable sheet, comprising the steps of: a step of forming a layered sheet including a light-adjustable layer including a transparent polymer layer including a plurality of domains and a liquid crystal composition filling the domains and including a liquid crystal compound and a dichroic dye, and a pair of transparent electrode layers, i.e., a first transparent electrode layer and a second transparent electrode layer, sandwiching the light-adjustable layer; and a step of irradiating an infrared laser from a side on which the first transparent electrode layer is positioned with respect to the light-adjustable layer of the layered sheet, in the first transparent electrode layer, forming a non-conductive portion extending in a linear shape and a conductive portion separated by the non-conductive portion.

2. The light control sheet according to claim 1, wherein, The average transmittance of light in an infrared region of the layered sheet is 64% or less.

3. The light control sheet according to claim 1, wherein, ​ 4. The light control sheet according to claim 1, wherein, ​ ​ ​ ​ ​ wherein ​

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