Light control sheet

Abstract

The light control sheet has a first transparent electrode sheet, a second transparent electrode sheet, and a light control layer between the first transparent electrode sheet and the second transparent electrode sheet. The light control layer includes a transparent polymer layer including a plurality of voids, a liquid crystal composition in the voids, and spacers. The liquid crystal composition includes a liquid crystal compound and a dichroic dye. A first luminance of the spacers is L1. A second luminance of the light control sheet in an opaque state is L2. A luminance difference is an absolute value obtained by subtracting the first luminance from the second luminance. An area occupancy (%) of the spacers in the light control layer in a plan view facing a plane in which the light control sheet extends is SR. A product value of the luminance difference and the area occupancy SR satisfies the following equation.

Description

Technical Field

[0001] This disclosure relates to dimming films. Background Technology

[0002] The dimming sheet includes a first transparent electrode sheet, a second transparent electrode sheet, and a dimming layer. The dimming layer is located between the first transparent electrode sheet and the second transparent electrode sheet. The dimming layer includes: a transparent polymer layer containing multiple voids; a liquid crystal compound located within the voids; and spacers defining the thickness of the dimming layer. The spacers are dispersed throughout the dimming layer (see, for example, Patent Document 1).

[0003] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2022-078443 Summary of the Invention

[0004] The problem that the invention aims to solve However, in the dimming sheets installed in the window glass of buildings, in order to improve the efficiency of light passing through the dimming sheet, it is required to increase the transmittance of the dimming sheet. Therefore, the spacers included in the dimming layer are mostly white granular spacers.

[0005] In recent years, the applications of dimming films have become increasingly diverse, such as partitions in offices or medical facilities, and windows in vehicles or airplanes. Because privacy is a requirement for dimming films used in these applications, dimming films containing dichroic pigments that display a specified color have been proposed. However, with such dimming films, compared to those without dichroic pigments, the difference in light transmitted at the locations of the spacers in the dimming layer and at the locations of the transparent polymer layer and liquid crystal compound tends to be larger. As a result, in-plane defects in the dimming film are easily generated.

[0006] Methods for solving problems One embodiment of a dimming film includes a first transparent electrode sheet, a second transparent electrode sheet, and a dimming layer located between the first and second transparent electrode sheets. The dimming film can reversibly switch between a transparent state and an opaque state depending on whether a voltage is applied to it. The dimming layer includes: a transparent polymer layer containing multiple voids, a liquid crystal composition located within the voids, and spacers. The liquid crystal composition includes a liquid crystal compound and a dichroic pigment. The first brightness of the spacers is... The second brightness of the dimming sheet exhibiting the aforementioned opaque state is From the aforementioned second brightness Subtract the first brightness mentioned above The absolute value obtained is the brightness difference. Viewed from above, facing the plane extending from the dimming plate, the area occupancy (%) of the spacers in the dimming layer is SR. The brightness difference... The product of the above area occupancy rate SR satisfies the following formula.

[0007] One embodiment of a dimming film includes a first transparent electrode sheet, a second transparent electrode sheet, and a dimming layer located between the first and second transparent electrode sheets. The dimming layer comprises: a transparent polymer layer containing a plurality of voids, a liquid crystal composition located within the voids, and spacers. The liquid crystal composition comprises a liquid crystal compound and a dichroic pigment. The first brightness of the spacers is... Viewed from above with respect to the plane extending from the dimming plate, the area occupancy of the spacers in the dimming layer is SR, and the first brightness... The product of the above area occupancy rate SR satisfies the following formula.

[0008] Attached Figure Description

[0009] Figure 1 This is a cross-sectional view showing the structure of a positive-type dimming disc.

[0010] Figure 2 This is a cross-sectional view showing the structure of a reverse-type dimming disc.

[0011] Figure 3 It means Figure 1 A cross-sectional view of the dimming layer structure of the dimming sheet shown.

[0012] Figure 4 This is a schematic diagram used to illustrate the test method for dimming films.

[0013] Figure 5 This is a table representing the evaluation results of the test cases.

[0014] Figure 6 This is a table representing the evaluation results of the test cases. Detailed Implementation

[0015] Reference Figures 1-3 One embodiment of the dimming sheet will be described below. The dimming sheet of this disclosure can be either a forward type or a reverse type. Hereinafter, after explaining the conditions satisfied by the dimming sheet of this disclosure regardless of its type, refer to... Figure 1 A positive dimming device with a positive dimming disc is described below, referring to... Figure 2 A reverse dimming device with a reverse dimming disc is described.

[0016] Furthermore, dimming sheets can be installed on transparent components of windows in moving vehicles such as vehicles and airplanes. Alternatively, dimming sheets can also be installed on transparent components of windows in various buildings such as residences, train stations, and airports, in office partitions, and in shop windows. The shape of the dimming sheet can be flat or curved.

[0017] [Dimming filter] [First Method] A first aspect of the dimming sheet disclosed herein includes a first transparent electrode sheet, a second transparent electrode sheet, and a dimming layer located between the first and second transparent electrode sheets. The dimming sheet can reversibly switch between a transparent state and an opaque state depending on whether a voltage is applied to it. The dimming layer includes: a transparent polymer layer containing a plurality of voids, a liquid crystal composition located within the voids, and spacers. The liquid crystal composition includes a liquid crystal compound and a dichroic pigment. The first brightness of the spacers is... The second brightness of the opaque dimming disc is From the second brightness Subtract the first brightness The absolute value obtained is the brightness difference. Viewed from above with respect to the plane extending from the dimming sheet, the area occupancy (%) of the spacers in the dimming layer is SR. The dimming sheet satisfies the following condition 1-1.

[0018] (Condition 1-1) Brightness difference The product of the area occupancy rate (SR) and the area occupancy rate (SR) satisfies the following formula.

[0019] When the amount of spacers in the dimming layer is at least the difference between the first brightness of each spacer and the second brightness of the dimming sheet (i.e., a large brightness difference), the spacers scattered throughout the dimming sheet are easily seen by an observer viewing the dimming sheet. On the other hand, even when the brightness difference is small, if the area occupied by all the spacers in the dimming layer is high, the probability of each spacer being seen by the observer is high, and the likelihood of the observer perceiving a collection of multiple spacers as a single object also increases. Therefore, the observer will perceive an uneven appearance of the dimming sheet within its plane. Unevenness is an example of poor appearance.

[0020] Regarding this, since the product of the brightness difference between the spacer and the dimming sheet and the area occupancy of the spacer satisfies the aforementioned range, the dimming sheet described above can suppress the brightness difference and area occupancy from becoming excessive. Therefore, the spacers in the dimming layer are difficult to see, thus suppressing unevenness in the in-plane appearance of the dimming sheet.

[0021] When it is required to further suppress the unevenness of the appearance of the dimming sheet within the plane, a brightness difference is preferred. The upper limit of the product of area occupancy (SR) and the area occupancy rate (SR) is small. The upper limit can be, for example, 70, 60, or 30.

[0022] Dimming films can also meet the following conditions 1-2 and 1-3.

[0023] (Condition 1-2) Brightness difference The value is between 20 and 74.

[0024] (Conditions 1-3) The area occupancy rate (SR) is 1% or more and 3% or less.

[0025] By ensuring that the dimming disc meets conditions 1-2 and 1-3, the brightness difference can be improved. The product of the area occupancy rate (SR) and the area occupancy rate (SR) satisfies the above-mentioned range of effectiveness.

[0026] [Second Method] A second embodiment of the dimming sheet disclosed herein includes a first transparent electrode sheet, a second transparent electrode sheet, and a dimming layer located between the first and second transparent electrode sheets. The dimming layer comprises: a transparent polymer layer containing a plurality of voids, a liquid crystal composition located within the voids, and spacers. The liquid crystal composition comprises a liquid crystal compound and a dichroic pigment. A first brightness of the spacers is... When the area occupancy of the spacers in the dimming layer is SR when viewed from above with respect to the plane of the dimming sheet, the dimming sheet satisfies the following condition 2-1.

[0027] (Condition 2-1) First brightness The product of the area occupancy rate (SR) and the area occupancy rate (SR) satisfies the following formula.

[0028] It possesses the brightness of an object. The higher the value, the less likely the object is to absorb light. Therefore, when the initial brightness of each spacer is high, the light not absorbed in each spacer is easily seen. Consequently, even if the area occupancy of the spacers in the dimming layer is low, the light transmitted through the spacers is easily seen, thus making a speckled appearance easily visible on the surface of the dimming sheet. On the other hand, even if the brightness of each spacer in the dimming layer is high... When the area ratio (SR) of the spacers is high, multiple spacers can easily be perceived as a single bright area. This makes the in-plane appearance of the dimmer sheet appear speckled. Furthermore, speckled appearance is an example of an appearance defect. A speckled appearance refers to the following: the spacers in the dimmer sheet are conspicuous relative to the rest of the sheet, thus creating the impression of speckles.

[0029] Regarding this point, according to the dimming disc of this disclosure, due to the first brightness of the spacer... The product of the area occupancy and the area ratio falls within the above range, thus minimizing the appearance of spots on the in-plane surface of the dimming film. In other words, it can suppress the appearance of spots on the in-plane surface of the dimming film.

[0030] When further suppression of the speckled appearance of the dimming disc is required, the preferred area occupancy ratio (SR) and the first brightness are... The upper limit of the product value is small. For example, the upper limit can be 0.65, 0.45, or 0.30.

[0031] The dimming disc can reversibly switch between transparent and opaque states depending on whether a voltage is applied to it. The second brightness of the aforementioned dimming disc when it is opaque is... Under these circumstances, the dimming film can meet the following condition 2-2.

[0032] (Condition 2-2) From the second brightness The absolute value obtained by subtracting the above product value satisfies the following formula.

[0033] When the dimming sheet meets condition 2-2, it can suppress the brightness difference between the dimming sheet and the spacer when the dimming sheet is opaque, thereby suppressing the spacer from being seen.

[0034] In cases where it is required to further suppress the speckled appearance of the dimming disc, it is preferable to use a second brightness. The upper limit of the absolute value obtained by subtracting the product is small. The upper limit can be, for example, 0.63, 0.45, 0.30, or 0.10.

[0035] The dimming film can also meet the following conditions 2-3 and 2-4.

[0036] (Conditions 2-3) First brightness It is 21 or higher and 27 or lower.

[0037] (Condition 2-4) The area occupancy rate (SR) is above 0.01 and below 0.03.

[0038] By using a dimming plate to satisfy conditions 2-3 and 2-4, the initial brightness of the spacer can be increased. The product of the area occupancy rate (SR) and the area occupancy rate (SR) satisfies the above-mentioned range of effectiveness.

[0039] [Positive dimming device] like Figure 1 As shown, the forward dimming device 10N includes a forward dimming plate 11N and a driving unit 12. The dimming plate 11N includes a first transparent electrode sheet 21, a second transparent electrode sheet 22, and a dimming layer 23. The dimming plate 11N is configured such that by switching between a state in which a voltage is applied between the first transparent electrode sheet 21 and the second transparent electrode sheet 22 and a state in which no voltage is applied, the dimming layer 23 can be switched between a transparent state and a non-transparent state.

[0040] The first transparent electrode sheet 21 has a first transparent electrode layer 21A and a first transparent substrate 21B supporting the first transparent electrode layer 21A. The second transparent electrode sheet 22 has a second transparent electrode layer 22A and a second transparent substrate 22B supporting the second transparent electrode layer 22A.

[0041] In the dimming sheet 11N, the dimming layer 23 is located between the first transparent electrode sheet 21 and the second transparent electrode sheet 22. The first transparent electrode layer 21A is located between the first transparent substrate 21B and the dimming layer 23. The second transparent electrode layer 22A is located between the second transparent substrate 22B and the dimming layer 23.

[0042] The dimming strip 11N exhibits transparency or opacity with a haze value higher than transparency, depending on the magnitude of the voltage applied to the dimming layer 23. The dimming strip 11N in the forward-type dimming device 10N is of the forward type, therefore, the dimming strip 11N is opaque when no voltage is applied to the dimming layer 23. Conversely, the dimming strip 11N is transparent when a voltage is applied to the dimming layer 23. In the forward-type dimming strip 11N, the state where the haze value reaches saturation in the V (voltage)-H (haze) curve when a voltage is applied to the dimming strip 11N represents the transparent state of the dimming strip 11N.

[0043] For example, the haze value of an opaque dimming sheet 11N can be 80% or more, and the haze value of a transparent dimming sheet 11N can be 5% or less. The haze value of the dimming sheet 11N is determined according to the method in JIS K 7136:2000 "Method for determining the haze of plastics - transparent materials".

[0044] The dimming plate 11N includes a first electrode 21E mounted on a portion of a first transparent electrode layer 21A and a second electrode 22E mounted on a portion of a second transparent electrode layer 22A. The dimming plate 11N further includes wiring 24 connected to the first electrode 21E and wiring 24 connected to the second electrode 22E. The first electrode 21E is connected to the driving unit 12 via wiring 24. The second electrode 22E is connected to the driving unit 12 via wiring 24.

[0045] The first transparent electrode sheet 21 and the second transparent electrode sheet 22 apply a voltage to the dimming layer 23, switching the dimming layer 23 between transparent and opaque states. Each transparent electrode sheet 21, 22 has light transmittance that allows visible light to pass through. The light transmittance of the first transparent electrode sheet 21 allows objects to be seen through the dimming sheet 11N. The light transmittance of the second transparent electrode sheet 22 is the same as that of the first transparent electrode sheet 21, allowing objects to be seen through the dimming sheet 11N.

[0046] The materials used to form the transparent electrode layers 21A and 22A can be, for example, any one selected from indium tin oxide, fluorine-doped tin oxide, tin oxide, zinc oxide, carbon nanotubes, and poly(3,4-ethylenedioxythiophene).

[0047] The materials forming the transparent substrates 21B and 22B can be synthetic resins or inorganic compounds. Synthetic resins include, for example, polyesters, polyacrylates, polycarbonates, and polyolefins. Polyesters include, for example, polyethylene terephthalate and polyethylene naphthalate. Polyacrylates include, for example, polymethyl methacrylate. Inorganic compounds include, for example, silicon dioxide, silicon oxynitride, and silicon nitride.

[0048] Each electrode 21E and 22E is, for example, a flexible printed circuit (FPC). The FPC includes a support layer, a conductor portion, and a protective layer. The conductor portion is sandwiched between the support layer and the protective layer. The support layer and the protective layer are formed of an insulating synthetic resin. For example, the support layer and the protective layer are formed of polyimide. The conductor portion is, for example, formed of a metal thin film. The material forming the metal thin film can be, for example, copper. Each electrode 21E and 22E is not limited to an FPC; for example, it can also be a metal strip.

[0049] Furthermore, each electrode 21E, 22E is mounted to each transparent electrode layer 21A, 22A via a conductive adhesive layer (not shown). At the portion of each electrode 21E, 22E that is connected to the conductive adhesive layer, the conductor portion is exposed from the protective layer or the support layer.

[0050] The conductive adhesive layer can be formed from, for example, anisotropic conductive film (ACF), anisotropic conductive paste (ACP), isotropic conductive film (ICF), and isotropic conductive paste (ICP). From the viewpoint of processability in the manufacturing process of the forward dimming device 10N, the conductive adhesive layer is preferably anisotropic conductive film.

[0051] Each wiring 24 is formed, for example, by a metal conductor and an insulating layer covering the metal conductor. The conductor is, for example, made of copper.

[0052] The driving unit 12 is configured to apply a voltage to the dimming layer 23 of the dimming sheet 11N. The driving unit 12 applies an alternating voltage between the first transparent electrode layer 21A and the second transparent electrode layer 22A. Preferably, the driving unit 12 applies an alternating voltage with a rectangular wave shape between the pair of transparent electrode layers 21A and 22A. In other words, the driving unit 12 preferably outputs a rectangular wave voltage signal.

[0053] [Reverse dimming device] Figure 2 The reverse-type dimming device 10R shown differs from the aforementioned forward-type dimming device 10N in that it includes a reverse-type dimming disc 11R. The differences between the reverse-type dimming device 10R and the forward-type dimming device 10N will be explained in detail below. Furthermore, in the reverse-type dimming device 10R, components common to the forward-type dimming device 10N are labeled with the same reference numerals as those in the forward-type dimming device 10N, and therefore, a detailed description of these components is omitted.

[0054] like Figure 2 As shown, the reverse-type dimming device 10R includes a reverse-type dimming sheet 11R and a driving unit 12. In addition to the layer structure of the forward-type dimming sheet 11N, the dimming sheet 11R also includes a first alignment film 21C and a second alignment film 22C. Therefore, in the reverse-type dimming device 10R, the first transparent electrode sheet 21 includes a first transparent electrode layer 21A and a first transparent substrate 21B, as well as a first alignment film 21C. The second transparent electrode sheet 22 includes a second transparent electrode layer 22A and a second transparent substrate 22B, as well as a second alignment film 22C.

[0055] The dimming layer 23 is located between the first alignment film 21C and the second alignment film 22C. The first alignment film 21C is located between the dimming layer 23 and the first transparent electrode layer 21A, and is in contact with the dimming layer 23. The second alignment film 22C is located between the dimming layer 23 and the second transparent electrode layer 22A, and is in contact with the dimming layer 23.

[0056] The materials used to form the first alignment film 21C and the second alignment film 22C can be organic compounds, inorganic compounds, or mixtures thereof. Organic compounds can be, for example, polyimide, polyamide, polyvinyl alcohol, and cyanide compounds. Inorganic compounds can be silicon oxide, zirconium oxide, etc. Furthermore, the materials used to form the alignment films 21C and 22C can also be organosilicon. Organosilicon is a compound possessing both inorganic and organic components.

[0057] The first alignment film 21C and the second alignment film 22C are, for example, vertical alignment films. The vertical alignment films are formed by aligning the long axis of the liquid crystal compound in a manner perpendicular to the surface opposite to the surface contacting the first transparent electrode layer 21A and the surface opposite to the surface contacting the second transparent electrode layer 22A. In this way, the alignment films 21C and 22C restrict the orientation of the plurality of liquid crystal compounds contained in the dimming layer 23.

[0058] The dimming strip 11R exhibits transparency or opacity with a higher haze value than transparency, depending on the voltage applied to the dimming layer 23. Since the dimming strip 11R of the reverse-type dimming device 10R is of the reverse type, it is transparent when no voltage is applied to the dimming layer 23. Conversely, it is opaque when a voltage is applied to the dimming layer 23. Therefore, the reverse-type dimming strip 11R is transparent when no voltage is applied. In the reverse-type dimming strip 11R, the opaque state is when the haze value reaches saturation in the V (voltage)-H (haze) curve when a voltage is applied to the dimming strip 11R.

[0059] For example, the haze value of an opaque dimming sheet 11R can be 80% or more, and the haze value of a transparent dimming sheet 11R can be 5% or less. The haze value of the dimming sheet 11R is determined according to the method in JIS K 7136:2000 "Method for determining the haze of plastics - transparent materials".

[0060] [Dimming Layer] Figure 3 The cross-sectional structure of the forward-aligning dimming film 11N is shown. In addition, the reverse-aligning dimming film 11R, besides having a first alignment film 21C and a second alignment film 22C, has the same... Figure 3 The structure shown is the same layered structure.

[0061] likeFigure 3 As shown, the dimming layer 23 comprises: a transparent polymer layer 23P containing a plurality of voids 23D, a liquid crystal composition 23LC located within the voids 23D, and spacers SP. The liquid crystal composition 23LC comprises a liquid crystal compound LCM and a dichroic pigment DD.

[0062] As described above, in the first method, when the brightness difference is Furthermore, when the area occupancy of the spacers SP in the dimming layer 23, viewed from above and facing the plane extending from the dimming plate 11N, is SR, the dimming plate satisfies condition 1-1. Additionally, in the spacers SP, by making the brightness difference... With a product of area occupancy SR of 20 or more, dimming layer 23 can contain a amount of spacers SP sufficient to suppress deviations in the thickness of dimming layer 23 within its plane.

[0063] On the other hand, in the second method, as described above, the first brightness of the spacer SP is Furthermore, when the area occupancy of the spacers SP in the dimming layer 23, viewed from above and facing the plane extending from the dimming plate 11N, is SR, the dimming plate satisfies condition 2-1. Additionally, in the spacers SP, by adjusting the area occupancy SR to match the first brightness... If the product value is 0.2 or higher, the dimming layer 23 can contain a amount of spacers SP sufficient to suppress deviations in the thickness of the dimming layer 23 within its plane.

[0064] The dimming layer 23 is in the form of a polymer dispersion. The polymer dispersion dimming layer 23 can be either a polymer network type or a capsule type. The polymer network type dimming layer 23 has a transparent polymer layer 23P with a three-dimensional mesh structure, and holds the liquid crystal composition 23LC within the interconnected mesh voids 23D. The capsule type dimming layer 23 holds the liquid crystal composition 23LC within the capsule-shaped voids 23D dispersed within the transparent polymer layer 23P.

[0065] [Liquid Crystal Composition] The liquid crystal composition 23LC comprises a liquid crystal compound LCM. The content of the liquid crystal compound LCM relative to the mass of the dimming layer 23 can be, for example, 40% by mass or more and 65% by mass or less. That is, the mass M23 of the dimming layer 23 and the mass MLCM of the liquid crystal compound LCM can satisfy the following mathematical formula. Furthermore, the mass M23 of the dimming layer 23 is the sum of the mass MLCM of the liquid crystal compound LCM, the mass M23P of the transparent polymer layer 23P, and the mass MSP of the spacer SP.

[0066] 40 (mass%) ≤ (MLCM / M23) × 100 ≤ 65 (mass%) The liquid crystal composition 23LC may also contain additives such as defoamers, antioxidants, weathering agents, solvents, and viscosity reducers. Weathering agents may be ultraviolet absorbers or light stabilizers.

[0067] Liquid crystal compounds (LCMs) can have positive dielectric anisotropy. When an LCM has positive dielectric anisotropy, the dielectric constant ε∥ along its long axis is higher than the dielectric constant ε⊥ along its short axis. LCMs can also have negative dielectric anisotropy. When an LCM has negative dielectric anisotropy, the dielectric constant ε∥ along its long axis is lower than the dielectric constant ε⊥ along its short axis. The dielectric anisotropy of the LCM can be appropriately selected based on the design of the dimming films 11N and 11R. For example, a forward-type dimming film 11N may include a liquid crystal compound LCM with positive dielectric anisotropy. For example, a reverse-type dimming film 11R may include a liquid crystal compound LCM with negative dielectric anisotropy.

[0068] Liquid crystal compounds (LCMs) are, for example, selected from at least one of the following: Schiff bases, azo compounds, azo oxides, biphenyl compounds, terphenyl compounds, benzoic acid esters, diphenylacetylene compounds, pyrimidine compounds, pyridazine compounds, cyclohexane carboxylate compounds, phenylcyclohexane compounds, biphenylcyclohexane compounds, dicyanophenyl compounds, naphthalene compounds, and dioxane compounds. A liquid crystal compound (LCM) is one LCM or a combination of two or more LCMs. The refractive index difference of the LCMs can be 0.05 or higher. The dielectric constant difference of the LCMs can be 2 or higher, or -2 or lower.

[0069] The structure of a liquid crystal compound (LCM) is represented by the following formula 1.

[0070] R 11 -A 11 -Z 11 -A 12 -Z 12 -A 13 -Z 13 -A 14 -R 12 Equation (1) R shown in Equation 1 11 It is an alkyl group with 1 or more hydrogen atoms and less than 20 carbon atoms. R 11 One or more non-adjacent methylene bonds in the alkyl group can be replaced by any one selected from oxygen atoms, ethylene bonds, ester bonds, and diether bonds. R shown in formula (1) 12It is a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group, a trifluoromethyl group, a trifluoromethoxy group, a difluoromethoxy group, or an alkyl group having 1 or more but less than 15 carbon atoms. R shown in formula (1) 12 One or more non-adjacent methylene bonds in the alkyl group can be replaced with any one selected from oxygen atoms, ethylene bonds, ester bonds, and diether bonds.

[0071] A shown in equation (1) 11 A 12 A 13 A 14 Each of the following groups independently represents 1,4-phenylene and 2,6-naphthylene. One or more hydrogen atoms in 1,4-phenylene and 2,6-naphthylene may be substituted with fluorine, chlorine, trifluoromethyl, or trifluoromethoxy atoms. Formula (1) shows A... 11 A 12 A 13 A 14 It can be independently 1,4-cyclohexene, 3,6-cyclohexenyl, 1,3-dioxane-2,5-diyl, or pyridine-2,5-diyl. A shown in formula (1) 13 A 14 Each can be a single bond independently. The Z shown in equation (1) 11 Z 12 Z 13 Each of these can be independently represented by a single bond, ester bond, diether bond, ethylene bond, fluoroethylene bond, or carbonyl bond.

[0072] [Transparent Polymer Layer] The transparent polymer layer 23P is a cured product of a photopolymerizable compound. The light used to polymerize the photopolymerizable compound can be ultraviolet light or an electron beam. The photopolymerizable compound can be an ultraviolet-polymerizable composition or an electron-beam-polymerizable composition. The lower and upper limits of the content of the transparent polymer layer 23P in the dimming layer 23 are within the range where liquid crystal particles composed of the liquid crystal compound LCM undergo phase separation from the polymer of the photopolymerizable compound during the polymerization process. When it is necessary to increase the mechanical strength of the transparent polymer layer 23P, a high lower limit of the content of the transparent polymer layer 23P is preferred. When it is necessary to reduce the voltage used to drive the liquid crystal compound LCM, a low upper limit of the content of the transparent polymer layer 23P is preferred.

[0073] The photocurable compound forming the transparent polymer layer 23P can be at least one selected from acrylate compounds, methacrylate compounds, styrene compounds, thiols, and oligomers of these compounds. The acrylate compound can be at least one selected from monoacrylate compounds, diacrylate compounds, triacrylate compounds, and tetraacrylate compounds. The acrylate compound can be at least one selected from butyl ethyl acrylate, ethylhexyl acrylate, and cyclohexyl acrylate. The methacrylate compound can be at least one selected from dimethacrylate compounds, trimethacrylate compounds, and tetramethacrylate compounds. The methacrylate compound can be at least one selected from N,N-dimethylaminoethyl methacrylate, phenoxyethyl methacrylate, methoxyethyl methacrylate, and tetrahydrofurfuryl methacrylate. The thiols compound can be 1,3-propanedithiol or 1,6-hexanedithiol. The styrene compound can be styrene or methylstyrene.

[0074] For example, by changing the size of the voids 23D in the transparent polymer layer 23P from a first value to a second value, the second brightness of the dimming plate 11N can be increased. Change from the first value to the second value.

[0075] [spacers] The spacer SP is dispersed throughout the transparent polymer layer 23P. The thickness of the spacer SP determines the thickness of the dimming layer 23. The thickness of the spacer SP can be determined by its particle size. The spacer SP ensures a uniform thickness of the dimming layer 23. The spacer SP can be a bead spacer or a photosensitive spacer formed by exposure and development with a photoresist. The spacer SP can be colorless and transparent, colored and transparent, or colored and opaque. Preferably, the color of the spacer SP is the same as the color exhibited by the dichroic pigment DD.

[0076] For example, the outer surface of the spacer SP can also be black. In this case, light transmission can be suppressed on the outer surface of the spacer SP, thus suppressing the visibility of locally transmitted light within the surface of the dimming sheet 11N. This further suppresses appearance defects within the surface of the dimming sheet 11N.

[0077] Alternatively, the spacer SP may have an outer surface and a central portion covered by the outer surface, with the central portion being black. In this case, since the central portion of the spacer SP is also black in addition to its outer surface, the absorbance of the spacer SP is further increased. As a result, the spacer SP becomes difficult to see because the transmission of light through it can be further suppressed. Consequently, in-plane appearance defects of the dimming sheet 11N can be further suppressed.

[0078] The total light transmittance of the spacer SP can be 30% or less. In this case, light transmission within the spacer SP can be suppressed, thus preventing the visible light from being partially transmitted within the surface of the dimming sheet 11N. When higher transmittance is required in a transparent dimming sheet 11N, the total light transmittance of the spacer's constituent materials can be, for example, 80% or more. The total light transmittance of the spacer SP is determined according to the method specified in ASTM D 1003-00, "Standard Test Method For Haze and Luminous Transmittance of Transparent Plastics".

[0079] For example, by changing the color of the spacer SP from a first color to a second color, the first brightness of the spacer SP can be increased. The first value is changed to the second value. Additionally, for example, by changing the area occupancy of the region exhibiting a predetermined color on the outer surface of the spacer SP from the first value to the second value, the first brightness of the spacer SP can be increased. Change from the first value to the second value.

[0080] For example, by changing the number of spacers SP per unit area from a first value to a second value, the area occupancy rate SR of the spacers SP can be changed from a first value to a second value. Additionally, for example, by changing the average diameter of the spacers SP from a first value to a second value, the area occupancy rate SR of the spacers SP can be changed from a first value to a second value.

[0081] The spacers SP can be spherical or cylindrical. The size of the spacers SP in the thickness direction of the dimming layer 23 is appropriately varied based on the required thickness of the dimming layer 23. The size of the spacers SP in the thickness direction of the dimming layer 23 can be, for example, 5 μm or more and 50 μm or less. When the spacers SP are spherical, the average particle size of the spacers can be, for example, 5 μm or more and 50 μm or less. The average particle size of the spacers SP is obtained using a particle size distribution measuring device that utilizes principles such as laser scattering, resistance value change, and image analysis after shooting. The average particle size of the spacers SP is the number-average particle size. When the spacers SP are cylindrical, the average diameter of the spacers is, for example, 5 μm or more and 50 μm or less. When power saving is required for the dimming sheets 11N and 11R, in order to reduce the thickness of the dimming layer 23, the average particle size or average diameter of the spacers SP is preferably, for example, 5 μm or more and 30 μm or less.

[0082] The average particle size of the spacer SP can be 5 μm or more and 30 μm or less. When the average particle size of the spacer SP falls within the range of 5 μm or more and 30 μm or less, the brightness difference can be improved in the first method. The product of the area occupancy rate SR and the actual value satisfying the above-mentioned range is effective. On the other hand, in the second method, when the average particle size of the spacer SP is within the range of 5 μm or more and 30 μm or less, the first brightness of the spacer SP can be improved. The product of the area occupancy rate SR satisfies the above-mentioned range of effectiveness.

[0083] As described above, the area occupancy percentage (SR) of the spacer SP can be, for example, 1% or more and 3% or less. In other words, as described above, the area occupancy percentage (SR) of the spacer SP can be, for example, 0.01 or more and 0.03 or less. The area occupancy percentage of the spacer SP is the ratio of the area occupied by the spacer SP in a unit area of ​​the dimming sheet 11N to that unit area. The area occupied by the spacer SP is obtained by observation of the transparent dimming sheet 11N from a viewpoint facing either of the two opposing sides in the thickness direction. An example of a unit area in the dimming sheet 11N is 1 mm × 1 mm. The area occupied by the spacer SP is calculated by observing the unit area of ​​the transparent dimming sheet 11N using an optical microscope. The small refractive index difference between the spacer SP and the transparent polymer layer 23P makes the area corresponding to the spacer SP appear slightly whiter than the surrounding area in the image captured by the optical microscope. Alternatively, the area corresponding to the spacer SP appears slightly blacker than the surrounding area in the image captured by the optical microscope. The area occupied by the spacer SP is obtained by summing the areas of the granular regions that appear slightly whiter than the surrounding area after binarization of the optical microscope image. When the spacer SP is spherical, the granular regions are spherical. When the spacer SP is cylindrical, the granular regions are rectangular.

[0084] The material forming the spacer SP can be an insulating transparent inorganic compound or an insulating transparent resin. The transparent inorganic compound is selected from silicon dioxide and alumina. The transparent resin is selected from at least one of acrylic resins, epoxy resins, phenolic resins, melamine resins, polyesters, polycarbonates, polyolefins, polyvinyl chloride, polyvinylidene chloride, polystyrene, and acetylcellulose. When the spacer SP is colored and transparent, the material forming the spacer SP can also be a transparent resin in which a colored pigment is dispersed. When the spacer SP is dispersed in a coating liquid used to form the dimming layer 23, i.e., a liquid containing a photocurable compound and a liquid crystal composition, the surface of the spacer SP can be subjected to a surface treatment to impart hydrophilicity to the coating liquid.

[0085] The refractive index of the material forming the spacer SP can be greater than 1.4 and less than 1.6. The refractive index of the material forming the spacer SP is different from the refractive index of the transparent polymer layer 23P constituting the dimming layer 23.

[0086] [Dichroic pigment] Dichroic pigments (DDs) exhibit color by being driven by a host-guest pattern based on a liquid crystal compound (LCM). Dichroic pigments (DDs) are, for example, selected from at least one of polyiodine, azo compounds, anthraquinone compounds, naphthoquinone compounds, methylimine compounds, tetrazine compounds, quinoline compounds, cyanine compounds, perylene compounds, and dioxazine compounds. A dichroic pigment (DD) can be a single compound or a combination of two or more compounds. When improved lightfastness and dichroism ratio are required, the dichroic pigment (DD) is preferably selected from at least one of azo compounds and anthraquinone compounds, more preferably an azo compound.

[0087] Dichroic pigments (DDs) preferably exhibit black color. When a dichroic pigment (DD) exhibits black color, it can be a single compound that produces a black color. Alternatively, a dichroic pigment (DD) can also exhibit black color through a combination of two or more compounds that exhibit a color different from black.

[0088] For example, by changing the content of dichroic pigment DD in the dimming layer 23 from a first value to a second value, the second brightness of the dimming plate 11N can be increased. Change from the first value to the second value.

[0089] [Manufacturing method of dimming film] The method for manufacturing a dimming film 11N includes the step of forming a coating film comprising a photopolymerizable compound, a liquid crystal compound (LCM), a dichroic pigment (DD), and a spacer (SP) between a first transparent electrode sheet 21 and a second transparent electrode sheet 22. When manufacturing a forward-type dimming film 11N, a coating film is formed between a first transparent electrode layer 21A of the first transparent electrode sheet 21 and a second transparent electrode layer 22A of the second transparent electrode sheet 22. Conversely, when manufacturing a reverse-type dimming film 11R, a coating film is formed between a first alignment film 21C of the first transparent electrode sheet 21 and a second alignment film 22C of the second transparent electrode sheet 22.

[0090] The coating contains a polymerization initiator for initiating the polymerization of a photopolymerizable compound. The polymerization initiator is, for example, at least one selected from diketone compounds, acetophenone compounds, benzoin compounds, thioxanone compounds, and oxime ester compounds. The polymerization initiator can be a single compound or a combination of two or more compounds. An example of a polymerization initiator is any one selected from benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, cyclohexylphenyl ketone, and phenylacetophenone.

[0091] The manufacturing method of the dimming sheets 11N and 11R includes a step of causing liquid crystal particles composed of a liquid crystal compound (LCM) to separate from the polymer by polymerizing a photopolymerizable compound in a coating film. Light irradiating the coating film may irradiate the first transparent electrode sheet 21, the second transparent electrode sheet 22, or both the first transparent electrode sheet 21 and the second transparent electrode sheet 22.

[0092] Phase separation of liquid crystal particles composed of a liquid crystal compound (LCM) is achieved through polymerization of a photopolymerizable compound and diffusion of the LCM. The polymerization rate of the photopolymerizable compound varies depending on the intensity of the light irradiating it. The diffusion rate of the LCM varies depending on the processing temperature during the polymerization of the photopolymerizable compound. During the phase separation of the LCM, the intensity of the light irradiating the photopolymerizable compound is set in a manner that shapes the liquid crystal particles to a desired size, i.e., shapes the 23D voids to a desired size. Additionally, heating can be performed during the phase separation of the LCM to promote diffusion.

[0093] When a reduction in the size of the void 23D is required, it is preferable to increase the intensity of the light irradiating the photopolymerizable compound and to perform polymerization at a low temperature for suppressing the diffusion of the liquid crystal compound LCM. When an increase in the size of the void 23D is required, it is preferable to decrease the intensity of the light irradiating the photopolymerizable compound and to perform polymerization at a high temperature for promoting the diffusion of the liquid crystal compound LCM.

[0094] [Experimental Example] Reference Figures 4-6 Test examples of the dimming film 11N will be described. Furthermore, the dimming film 11N in each test example is a forward-facing type. A coating film containing a photopolymerizable compound and a liquid crystal compound (LCM) is formed between a first transparent electrode sheet 21 and a second transparent electrode sheet 22. Then, the photopolymerizable compound is polymerized in the coating film, thereby obtaining the dimming film 11N.

[0095] To form the dimmer 11N for the test example, the following materials were used.

[0096] [Material] • First transparent electrode layer 21A: Indium tin oxide • Second transparent electrode layer 22A: Indium tin oxide • First transparent substrate 21B: Polyethylene terephthalate film • Second transparent substrate 22B: Polyethylene terephthalate film • Liquid Crystal Compounds (LCMs): Biphenyl-based liquid crystal compounds, terphenyl-based liquid crystal compounds, diphenylacetylene-based liquid crystal compounds, cyclohexane carboxylate-based liquid crystal compounds, phenylcyclohexane-based liquid crystal compounds, biphenylcyclohexane-based liquid crystal compounds, cyano-based liquid crystal compounds, fluorine-based liquid crystal compounds, 54 parts by weight • Dichroic pigments (DD): 0.5 parts by weight of blue dichroic pigment (product name M-412: manufactured by Mitsui Chemicals Fine Co., Ltd.) and 1.5 parts by weight of black dichroic pigment (product name YH-428: manufactured by Mitsui Chemicals Fine Co., Ltd.). • Polymerization initiator: 1-hydroxycyclohexylphenyl ketone, 3 parts by weight • Spacer SP: spherical shape with a diameter of 25 μm • UV-polymerizable compounds: isobornyl acrylate, pentaerythritol triacrylate, urethane acrylate, 41 parts by weight [Experimental Example 1] A coating solution was prepared by mixing a liquid crystal compound (LCM), a dichroic pigment (DD), and an ultraviolet-polymerizable compound. Next, a spacer (SP) was mixed in a ratio of 1 part by weight to 100 parts by weight of the coating solution, and a polymerization initiator was mixed in a ratio of 3 parts by weight to the same 100 parts by weight of the coating solution. The spacer (SP) was then used, exhibiting a black outer surface and a black central portion. Next, a coating film with a thickness of 25 μm was formed on the first transparent electrode layer 21A using the coating solution. Then, with the coating film sandwiched between the first transparent electrode layer 21A and the second transparent electrode layer 22A, ultraviolet light with a wavelength of 365 nm was irradiated toward the first transparent substrate 21B. This yielded the dimming disc 11N of Experimental Example 1. The intensity of the ultraviolet light was set to 10 mW / cm². 2 And the ultraviolet irradiation time was set to 100 seconds.

[0097] [Experimental Example 2] In Test Example 1, spacer SP was added in a ratio of 3 parts by weight to 100 parts by weight of coating liquid. Otherwise, the dimming sheet 11N of Test Example 2 was obtained by the same method as in Test Example 1.

[0098] [Experimental Example 3] In Experiment 1, the spacer SP was changed to a spacer SP with a black outer surface and a white central part covered by the outer surface. Otherwise, the dimming sheet 11N of Experiment 3 was obtained by the same method as in Experiment 1.

[0099] [Experimental Example 4] In Experiment 3, the content of spacer SP was changed to 3 parts by weight relative to 100 parts by weight of coating liquid. Otherwise, the dimming sheet 11N of Experiment 4 was obtained by the same method as in Experiment 3.

[0100] [Experimental Example 5] In Experiment 1, the spacer SP was changed to a spacer SP with a white outer surface and central portion, and the proportion of the dichroic pigment DD in the coating solution was reduced when preparing the coating solution by mixing the liquid crystal compound LCM, the dichroic pigment DD, and the ultraviolet polymerizable compound. Otherwise, the dimming film 11N of Experiment 5 was obtained by the same method as in Experiment 1.

[0101] [Experimental Example 6] In Example 1, the content of spacer SP was changed to 4 parts by weight relative to 100 parts by weight of coating liquid. Otherwise, the dimming sheet 11N of Example 6 was obtained by the same method as in Example 1.

[0102] [Experimental Example 7] In Experiment 3, the content of spacer SP was changed to 4 parts by weight relative to 100 parts by weight of coating liquid. Otherwise, the dimming sheet 11N of Experiment 7 was obtained by the same method as in Experiment 3.

[0103] [Experimental Example 8] In Experiment 1, the spacer SP was made to have a white outer surface and a white central portion covered by the outer surface. Otherwise, the dimming sheet 11N of Experiment 8 was obtained by the same method as in Experiment 1.

[0104] [Evaluation Method] Total light transmittance The total light transmittance of the dimming sheets 11N in each embodiment and comparative example was measured according to the method of ASTM D 1003-00. No voltage was applied to each dimming sheet 11N at this time. That is, the total light transmittance of the dimming sheet 11N was measured when it was opaque and had the highest haze value.

[0105] Similar to the dimmer plate 11N, the total light transmittance of each spacer SP is determined according to the method of ASTM D 1003-00. At this time, the spacers SP are filled into a glass sample holder in a manner that ensures the spacers are completely filled without gaps, thereby preparing the sample for measurement. Then, the total light transmittance of the sample for measurement is measured.

[0106] The total light transmittance of the dimming plate 11N and the spacer SP was measured using a haze meter (BYK haze-gard instrument, manufactured by BYK Gardner).

[0107] [Area Occupancy Rate] In the dimming sheet 11N of each embodiment and comparative example, nine measurement areas were set up for measuring the area occupancy rate, and these areas did not overlap when viewed from above facing the plane extending from the dimming sheet 11N. Each measurement area was set to a square shape with one side length of 1 mm, and the nine measurement areas were arranged in a three-row, three-column, equally spaced configuration. Next, the measurement areas of each dimming sheet 11N were photographed using an optical microscope, thereby obtaining an image of each measurement area. After binarizing the photographed images, the total area of ​​the granular areas that appeared slightly white or black compared to the surrounding area was calculated. Then, the area occupancy rate of the spacers SP in the measurement areas was calculated by dividing the total value by the area of ​​the measurement areas. For the dimming sheet 11N of each embodiment and comparative example, the average area occupancy rate of the nine measurement areas was calculated, and this average value was then set as the area occupancy rate of the spacers SP in each embodiment and comparative example.

[0108] [brightness To achieve the second brightness of the 11N dimmer filter First, the Y-value of the dimmer 11N in the state where no voltage is applied, i.e., when the dimmer is opaque, is calculated. Then, the spectrophotometric reflectance in the range of 360 nm to 830 nm is measured using a spectrophotometer (UH4150, Hitachi High-Tech Corporation). Next, following the method in JIS Z8781-3:2016 "Colorimetry - Part 3: CIE Tristimulus Values", the Y-value of the dimmer 11N when the Y-value of a fully diffuse reflector is set to 100 is calculated based on the spectrophotometer measurement results.

[0109] Next, according to JIS Z 8781-4:2013 "Colorimetry - Part 4: The second brightness is calculated from the Y value of the dimming filter 11N using the "color space" method. .

[0110] The first brightness of the spacer SP was obtained. First, similar to the determination of the total light transmittance of the spacer SP, the spacer SP is filled into a glass sample holder in a manner that ensures it is completely filled without gaps, thus preparing the sample for measurement. Next, the sample is measured using a second brightness... After obtaining the Y value of the spacer SP using the same method, the first brightness is calculated from the Y value. .

[0111] [Visual Evaluation] pass Figure 4 The method shown is used for visual evaluation of the dimming film 11N.

[0112] like Figure 4 As shown, a light source is positioned opposite the second transparent electrode sheet 22 of the dimming plate 11N, and an observer OB is positioned on the side opposite to the light source relative to the dimming plate 11N. Next, light L is shone from the light source onto the second transparent electrode sheet 22 of the dimming plate 11N, which is not under voltage. Then, the observer OB visually observes the light transmitted through the dimming plate 11N. Based on the visual observation results, the observation results regarding unevenness in appearance are evaluated according to the following two levels.

[0113] [Uneven appearance] A: The spacers SP are almost invisible, so the unevenness of the appearance of the dimming disc 11N is almost invisible.

[0114] B: Transmitted light can be seen on the spacers SP dispersed within the surface of the dimming plate 11N, thus revealing the unevenness of the surface appearance within the dimming plate 11N.

[0115] In addition, based on visual observations, the observations of the appearance of spots were evaluated at the following two levels.

[0116] [The appearance has a speckled look] A: The spacers SP are almost invisible, so the speckled appearance of the in-plane appearance of the dimming disc 11N is almost invisible.

[0117] B: The spacers SP dispersed within the surface of the dimmer 11N are raised and seen from the dimmer 11N, thus creating a speckled appearance within the surface of the dimmer 11N.

[0118] [Evaluation Results] The evaluation results of the 11N dimming film in each test example are as follows: Figure 5 and Figure 6 As shown.

[0119] It can be seen that the total light transmittance of the dimmer sheet 11N is 6.6% in Test Example 1, 6.9% in Test Example 2, 6.7% in Test Example 3, 7.3% in Test Example 4, and 14.1% in Test Example 5. It can also be seen that the total light transmittance of the dimmer sheet 11N is 7.0% in Test Example 6, 7.5% in Test Example 7, and 5.1% in Test Example 8.

[0120] The total light transmittance of the visible spacer SP was 21.0% in Test Examples 1, 2 and 6, 27.0% in Test Examples 3, 4 and 7, and 86.0% in Test Examples 5 and 8.

[0121] It can be seen that the area occupancy of the spacer SP is 1% in Test Examples 1, 3, 5 and 8, 3% in Test Examples 2 and 4, and 4% in Test Examples 6 and 7. This means that the area occupancy of the spacer SP is 0.01 in Test Examples 1, 3, 5 and 8, 0.03 in Test Examples 2 and 4, and 0.04 in Test Examples 6 and 7.

[0122] The second brightness of the visible dimming disc 11N The value was 0.1719 in Test Example 1, 0.1750 in Test Example 2, 0.1729 in Test Example 3, 0.1794 in Test Example 4, and 15.4247 in Test Example 5. This shows the second brightness of the 11N dimmer. The value was 0.1761 in Test Example 6, 0.1817 in Test Example 7, and 0.1582 in Test Example 8.

[0123] The first brightness of the visible spacer SP The value was 21.0 in Test Examples 1, 2 and 6, 27.0 in Test Examples 3, 4 and 7, and 88.9 in Test Examples 5 and 8.

[0124] It can be seen from the first brightness Subtract the second brightness The resulting brightness difference The value was 20.828 in Test Example 1, 20.825 in Test Example 2, 26.827 in Test Example 3, 26.821 in Test Example 4, and 73.475 in Test Example 5. The brightness difference is evident. The value was 20.824 in Test Example 6, 26.818 in Test Example 7, and 88.742 in Test Example 8.

[0125] Visible brightness difference The product of the area occupancy rate (SR) and the area occupancy rate (SR) was 20.828 in Test Example 1, 62.475 in Test Example 2, 26.827 in Test Example 3, 80.462 in Test Example 4, and 73.475 in Test Example 5. This indicates a difference in brightness. The product of the area occupancy rate (SR) and the area occupancy rate (SR) was 83.296 in Experiment 6, 107.273 in Experiment 7, and 88.742 in Experiment 8.

[0126] The visible spacer SP's area occupancy SR and the first brightness The product value was 0.21 in Test Example 1, 0.63 in Test Example 2, 0.27 in Test Example 3, and 0.81 in Test Example 4. It can be seen that the area occupancy SR of the spacer SP is related to the first brightness. The product value is 0.889 in Test Example 5, 0.84 in Test Example 6, 1.08 in Test Example 7, and 0.889 in Test Example 8.

[0127] It can be seen from the second brightness Subtract area occupancy SR and first brightness The product of these values ​​is 0.0381 in Test Example 1, 0.455 in Test Example 2, 0.0971 in Test Example 3, and 0.6306 in Test Example 4. It can be seen that from the second brightness... Subtract area occupancy SR and first brightness The product of these values ​​is 14.5357 in Test Example 5, 0.6639 in Test Example 6, 0.8983 in Test Example 7, and 0.708 in Test Example 8.

[0128] It is evident that the evaluation results based on visual unevenness are "A" in Experiments 1-5 and "B" in Experiments 6-8. Similarly, the evaluation results based on visual spot perception are "A" in Experiments 1-4 and "B" in Experiments 5-8.

[0129] Therefore, it can be seen that in the dimming disc 11N, by making the brightness difference... When the product of the area occupancy ratio SR is 20 or more and 81 or less, the unevenness of the appearance of the dimming film 11N within the plane can be suppressed.

[0130] Furthermore, it can be seen that in the spacer SP, by making the area occupancy SR equal to the first brightness... The product value is less than 0.81, which can suppress the spotting effect on the in-plane appearance of the dimming film 11N.

[0131] As explained above, according to one embodiment of the dimming film, the following effects can be obtained.

[0132] (1) Due to the difference in brightness The product of the area occupancy ratio SR satisfies condition 1-1, making it difficult to see the unevenness of the in-plane appearance of the dimming sheets 11N and 11R. That is, it can suppress the unevenness of the in-plane appearance of the dimming sheets 11N and 11R.

[0133] (2) Due to the first brightness of the spacer SP The product of the area occupancy SR and the area occupancy SR satisfies condition 2-1, thus making it difficult to see the speckled appearance of the dimming films 11N and 11R. That is, it is possible to suppress the speckled appearance of the dimming films 11N and 11R.

[0134] (3) When the dimming sheets 11N and 11R meet the conditions 2-2, when the dimming sheets 11N and 11R are opaque, the brightness difference between the dimming sheets 11N and 11R and the spacer SP can be suppressed, thus suppressing the appearance of spots.

[0135] (4) When the outer surface of the spacer SP is black, light transmission can be suppressed on the outer surface of the spacer SP, thus suppressing the visibility of locally transmitted light within the planes of the dimming sheets 11N and 11R. As a result, appearance defects within the planes of the dimming sheets 11N and 11R can be further suppressed.

[0136] (5) When the center of the spacer SP is also black except for the outer surface of the spacer SP, the absorbance of the spacer SP is further increased. As a result, the light transmission in the spacer SP can be further suppressed, and the spacer SP becomes difficult to see. As a result, the in-plane appearance defects of the dimming sheets 11N and 11R can be further suppressed.

[0137] (6) When the total light transmittance of the spacer SP is less than 30%, the transmission of light in the spacer SP can be suppressed, thus suppressing the local transmission of light in the planes of the dimming plates 11N and 11R from being seen.

Claims

1. A dimming film, comprising: First transparent electrode sheet; Second transparent electrode sheet; and A dimming layer located between the first transparent electrode sheet and the second transparent electrode sheet. The dimming plate can reversibly switch between a transparent state and an opaque state depending on whether a voltage is applied to it. The dimming layer comprises: a transparent polymer layer containing multiple pores, a liquid crystal composition located within the pores, and spacers. The liquid crystal composition comprises a liquid crystal compound and a dichroic pigment. The first brightness of the spacer is The second brightness of the dimming sheet in the opaque state is From the second brightness Subtract the first brightness The absolute value obtained is the brightness difference. Viewed from above with respect to the plane extending from the dimming sheet, the area occupancy (%) of the spacers in the dimming layer is SR. The brightness difference The product of the area occupancy rate SR and the area occupancy rate SR satisfies the following formula: 。 2. The dimming film according to claim 1, wherein, The brightness difference L The value is between 20 and 74. The area occupancy rate (SR) is above 1% and below 3%.

3. A dimming film, comprising: First transparent electrode sheet; Second transparent electrode sheet; and A dimming layer located between the first transparent electrode sheet and the second transparent electrode sheet, wherein, The dimming layer comprises: a transparent polymer layer containing multiple pores, a liquid crystal composition located within the pores, and spacers. The liquid crystal composition comprises a liquid crystal compound and a dichroic pigment. The first brightness of the spacer is Viewed from above with respect to the plane extending from the dimming plate, the area occupancy of the spacers in the dimming layer is SR. The first brightness The product of the area occupancy rate SR and the area occupancy rate SR satisfies the following formula: 。 4. The dimming film according to claim 3, wherein, The dimming plate can reversibly switch between transparent and opaque depending on whether a voltage is applied to it. The second brightness of the opaque dimming sheet is From the second brightness The absolute value obtained by subtracting the product value satisfies the following equation: 。 5. The dimming film according to claim 3, wherein, The first brightness For those with a score between 21 and 27, The area occupancy rate (SR) is above 0.01 and below 0.

03.

6. The dimming film according to any one of claims 1 to 5, wherein, The outer surface of the spacer is black.

7. The dimming film according to claim 6, wherein, The spacer has an outer surface and a central portion covered by the outer surface. The central part is black.

8. The dimming film according to any one of claims 1 to 5, wherein, The total light transmittance of the spacer is less than 30%.

9. The dimming film according to any one of claims 1 to 5, wherein, The average diameter of the spacers is greater than 5 μm and less than 30 μm.

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