dimmer

Abstract

To provide a dimmer which enables further decoration to a mounting object in addition to transparence and opacity.SOLUTION: A first dimmer 10N includes a first dimming sheet 11N, and a driving part 12 for applying a voltage to the first dimming sheet 11N. The haze of the first dimming sheet 11N under application of a first voltage VN1 is 80% or more, and the haze of the first dimming sheet 11N under application of a second voltage VN2 is less than 10%. In the first dimming sheet 11N, a differential value in a lightness index L* between under application of the second voltage VN2 and under application of a third voltage VN3 is 20 or more, a differential value in a color coordinate a* between under application of the second voltage VN2 and under application of the third voltage VN3 is 15 or more, or a differential value in a color coordinate b* therebetween is 20 or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a light control device. [Background technology]

[0002] Light control sheets are of either normal or reverse type. Normal-type light control sheets comprise a first transparent electrode layer, a second transparent electrode layer, and a light control layer located between the first and second transparent electrode layers. The light control layer contains positive liquid crystal molecules. Reverse-type light control sheets further comprise a first alignment layer and a second alignment layer in addition to the normal-type sheet. The first alignment layer is located between the light control layer and the first transparent electrode layer, and the second alignment layer is located between the light control layer and the second transparent electrode layer.

[0003] In a light control device equipped with a normal-type light control sheet, the light control sheet is opaque when no potential difference occurs between the transparent electrode layers, but is transparent when a potential difference occurs between the transparent electrode layers. In contrast, in a light control device equipped with a reverse-type light control sheet, the light control sheet is transparent when no potential difference occurs between the transparent electrode layers, but is opaque when a potential difference occurs between the transparent electrode layers (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-9187 Summary of the Invention [Problem to be solved by the invention]

[0005] Light-controlling sheets are attached to transparent components found in windows in various buildings, partitions installed in offices, and show windows installed in stores. In recent years, light-controlling sheets have also begun to be applied to transparent components found in windows in moving objects such as vehicles and aircraft. As the range of objects to which light-controlling sheets can be attached expands in this way, there is a demand for light-controlling sheets that can be further decorated in addition to being transparent or opaque to the objects to which they are attached. [Means for solving the problem]

[0006] A light-controlling device for solving the above problem includes a light-controlling sheet having a light-controlling layer including a first transparent electrode layer, a second transparent electrode layer, a transparent polymer layer positioned between the first and second transparent electrode layers and including a plurality of voids, and a liquid crystal composition filled in the voids; and a driving unit that applies a voltage to the light-controlling sheet. The driving unit applies a first voltage, a second voltage, and a third voltage to the light-controlling sheet, and at the first voltage, the potential difference between the first and second transparent electrode layers is zero, and the third voltage has a magnitude between the first and second voltages. The haze of the light-controlling sheet when the first voltage is applied is 80% or more, and the haze of the light-controlling sheet when the second voltage is applied is less than 10%. In the light-controlling sheet, the lightness index L when the second voltage is applied and when the third voltage is applied is * the difference between the color coordinates a when the second voltage is applied and the color coordinate a when the third voltage is applied is 20 or more; * The difference value of is 15 or more, or the color coordinate b * The difference value is 20 or more.

[0007] According to the above light-adjusting device, by applying the third voltage to the light-adjusting sheet, the light becomes darker than when the second voltage is applied, and the color coordinate a * or color coordinate b * When the second voltage is applied, the light-controlling sheet can exhibit a color different from that when the first voltage is applied.

[0008] In the light-adjusting device, the lightness index L when the second voltage is applied and when the first voltage is applied to the light-adjusting sheet is * the difference between the color coordinates a when the second voltage is applied and the color coordinates a when the first voltage is applied is 90 or more, * the difference between the color coordinates b * The difference value may be 3.0 or less.

[0009] According to the above-mentioned dimming device, when a second voltage is applied to the dimming sheet, the dimming sheet can be made brighter than when a first voltage is applied, while still exhibiting a color that is little different from the color exhibited by the dimming sheet when the first voltage is applied.

[0010] In the above light-adjusting device, the color coordinate a * and the color coordinate b * may have a maximum value at a voltage having a magnitude between the first voltage and the second voltage. * ,b * By applying a voltage to the light-control sheet at which the color coordinate a * ,b * In this case, it is possible to maximize the deviation of the color exhibited by the light-controlling sheet from the color exhibited by the light-controlling sheet when the first voltage or the second voltage is applied to the light-controlling sheet.

[0011] A light control device for solving the above problem includes a light control sheet including a first transparent electrode layer, a second transparent electrode layer, a light control layer positioned between the first transparent electrode layer and the second transparent electrode layer and including a transparent polymer layer having a plurality of voids and a liquid crystal composition filled in the voids, a first alignment layer positioned between the first transparent electrode layer and the light control layer, and a second alignment layer positioned between the second transparent electrode layer and the light control layer, and a drive unit that applies voltages to the light control sheet. The drive unit applies a first voltage, a second voltage, and a third voltage to the light control sheet, where the potential difference between the first transparent electrode layer and the second transparent electrode layer is zero at the second voltage, and the third voltage has a magnitude between the first voltage and the second voltage. The haze of the light-controlling sheet is 80% or more when the first voltage is applied, the first voltage being the minimum voltage value at which the haze of the light-controlling sheet is 80% or more, and the haze of the light-controlling sheet is 15% or less when the second voltage is applied. * the difference between the color coordinates a when the second voltage is applied and the color coordinate a when the third voltage is applied is 20 or more; * The difference value of is 15 or more, or the color coordinate b * The difference value is 20 or more.

[0012] According to the above light-adjusting device, by applying the third voltage to the light-adjusting sheet, the light becomes darker than when the second voltage is applied, and the color coordinate a * or color coordinate b * When the second voltage is applied, the light-controlling sheet can exhibit a color different from that when the first voltage is applied.

[0013] In the light-adjusting device, the color coordinate b * The difference may be equal to or greater than 30. With this light-adjusting device, when the third voltage is applied to the light-adjusting sheet, the light-adjusting sheet can exhibit a color that is significantly different from when the second voltage is applied to the light-adjusting sheet.

[0014] In the light-adjusting device, the color coordinate b * the difference between the brightness index L when the second voltage is applied and the brightness index L when the first voltage is applied is 20 or more, * The difference between the color coordinates b * The difference value may be 20 or more.

[0015] According to the above-mentioned dimming device, the dimming sheet can exhibit a different color when the second voltage is applied to the dimming sheet and when the third voltage is applied to the dimming sheet than when the first voltage is applied. [Effects of the Invention]

[0016] According to the present invention, when a third voltage, which is between the first voltage and the second voltage, is applied to the light-controlling sheet, the sheet can exhibit a different color than when the second voltage is applied. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view showing the structure of a light control device including a normal-type first light control sheet, which is a first example of the light control device. [Figure 2] FIG. 10 is a cross-sectional view showing the structure of a second example of a light control device, which is a light control device including a reverse-type second light control sheet. [Figure 3] FIG. 1 is a schematic diagram showing color intervals defined by the L*a*b* color system. [Figure 4] 10 is a table showing the relationship between the drive voltage and the optical characteristics of the light controlling sheet in the light controlling device of Example 1-1. [Figure 5] 10 is a table showing the relationship between the drive voltage and the optical characteristics of the light controlling sheet in the light controlling device of Comparative Example 1-1. [Figure 6] 10 is a table showing the relationship between the drive voltage and the optical characteristics of the light-control sheet in the light-control device of Comparative Example 1-2. [Figure 7]10 is a table showing the relationship between the drive voltage and the optical characteristics of the light controlling sheet in the light controlling device of Example 2-1. [Figure 8] 10 is a table showing the relationship between the drive voltage and the optical characteristics of the light controlling sheet in the light controlling device of Example 2-2. [Figure 9] 10 is a table showing the relationship between the drive voltage and the optical characteristics of the light-controlling sheet in the light-controlling device of Example 2-3. [Figure 10] 10 is a table showing the relationship between the drive voltage and the optical characteristics of the light controlling sheet in the light controlling device of Comparative Example 2-1. DETAILED DESCRIPTION OF THE INVENTION

[0018] An embodiment of a light control device will be described with reference to Figures 1 to 10. The light control sheet provided in the light control device of the present disclosure may be of either a normal type or a reverse type. Below, a first light control device including a normal type first light control sheet and a drive unit will be described with reference to Figure 1, and a second light control device including a reverse type second light control sheet and a drive unit will be described with reference to Figure 2.

[0019] The light-controlling sheet is attached to transparent members such as window glass in various buildings such as homes, train stations, and airports, partitions in offices, and show windows in stores. Alternatively, the light-controlling sheet is attached to transparent members in windows of moving objects such as vehicles and aircraft. The light-controlling sheet may be flat or curved.

[0020] [1st light control device] 1, the first light control device 10N includes a normal-type first light control sheet 11N and a drive unit 12. The first light control sheet 11N includes a first transparent electrode layer 21, a second transparent electrode layer 22, and a light control layer 23. The first light control sheet 11N further includes a first transparent substrate 24 that supports the first transparent electrode layer 21, and a second transparent substrate 25 that supports the second transparent electrode layer 22.

[0021] The first light controlling sheet 11N includes a first electrode 21E attached to a portion of the first transparent electrode layer 21, and a second electrode 22E attached to a portion of the second transparent electrode layer 22. The first light controlling sheet 11N further includes a wiring 26 connected to the first electrode 21E, and a wiring 26 connected to the second electrode 22E. The first electrode 21E is connected to the driving unit 12 by the wiring 26. The second electrode 22E is connected to the driving unit 12 by the wiring 26.

[0022] The first transparent electrode layer 21 and the second transparent electrode layer 22 apply a voltage to the light control layer 23 to switch the light control layer 23 between transparent and opaque. Each transparent electrode layer 21, 22 has optical transparency that allows visible light to pass through. The optical transparency of the first transparent electrode layer 21 enables visual recognition of objects through the first light control sheet 11N. The optical transparency of the second transparent electrode layer 22, like the optical transparency of the first transparent electrode layer 21, also enables visual recognition of objects through the first light control sheet 11N.

[0023] The material for forming each of the transparent electrode layers 21 and 22 may be, for example, any one selected from the group consisting of indium tin oxide, fluorine-doped tin oxide, tin oxide, zinc oxide, carbon nanotubes, and poly(3,4-ethylenedioxythiophene).

[0024] The light-controlling layer 23 includes a transparent polymer layer and a liquid crystal composition. The transparent polymer layer has voids that are filled with the liquid crystal composition. The liquid crystal composition fills the voids in the transparent polymer layer. The voids may be spherical, ellipsoidal, or irregular in shape. When the voids have a circular shape in a cross section taken along the thickness direction of the first light-controlling sheet 11N, the void diameter is the diameter of the void. When the voids have an elliptical shape in a cross section taken along the thickness direction of the first light-controlling sheet 11N, the void diameter is the major axis of the void. When the voids have an irregular shape in a cross section taken along the thickness direction of the first light-controlling sheet 11N, the void diameter is the diameter of a circle circumscribing the void. The void diameter may be, for example, 0.5 μm or more and 5.0 μm or less, and preferably 1.5 μm or more and 3.0 μm or less.

[0025] The type of liquid crystal composition retention is any one selected from the group consisting of a polymer network type, a polymer dispersion type, and a capsule type. The polymer network type has a transparent polymer network with a three-dimensional mesh structure, and retains the liquid crystal composition in the interconnected voids of the mesh. The polymer network is an example of a transparent polymer layer. The polymer dispersion type has a large number of isolated voids in a transparent polymer layer, and retains the liquid crystal composition in the voids dispersed in the transparent polymer layer. The capsule type retains a capsule-shaped liquid crystal composition in a transparent polymer layer. This forms voids in the transparent polymer layer into which the liquid crystal composition is filled.

[0026] The liquid crystal composition contains liquid crystal molecules. An example of the liquid crystal molecules is at least one selected from the group consisting of Schiff base-based, azo-based, azoxy-based, biphenyl-based, terphenyl-based, benzoate ester-based, tolan-based, pyrimidine-based, pyridazine-based, cyclohexanecarboxylic acid ester-based, phenylcyclohexane-based, biphenylcyclohexane-based, dicyanobenzene-based, naphthalene-based, and dioxane-based. The liquid crystal composition contains, as liquid crystal molecules, positive-type nematic liquid crystals with positive dielectric anisotropy.

[0027] The transparent polymer layer is a cured product of a photopolymerizable compound. The photopolymerizable compound may be an ultraviolet-curable compound or an electron beam-curable compound. The photopolymerizable compound is compatible with the liquid crystal composition. When improving the dimensional controllability of the voids, the photopolymerizable compound is preferably an ultraviolet-curable compound. An example of the ultraviolet-curable compound contains a polymerizable unsaturated bond at the end of the molecular structure. Alternatively, the ultraviolet-curable compound contains a polymerizable unsaturated bond at a position other than the end of the molecular structure. The photopolymerizable compound is one type of polymerizable compound or a combination of two or more types of polymerizable compounds.

[0028] The ultraviolet curable compound is at least one selected from the group consisting of acrylate compounds, methacrylate compounds, styrene compounds, thiol compounds, and oligomers of each compound.

[0029] Acrylate compounds include monoacrylate compounds, diacrylate compounds, triacrylate compounds, and tetraacrylate compounds. Examples of acrylate compounds are butyl ethyl acrylate, ethylhexyl acrylate, and cyclohexyl acrylate. Examples of methacrylate compounds are 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 thiol compounds are 1,3-propanedithiol and 1,6-hexanedithiol. Examples of styrene compounds are styrene and methylstyrene.

[0030] The lower limit of the content of the transparent polymer layer relative to the total amount of the transparent polymer layer and the liquid crystal composition may be 30% by mass, more preferably 40% by mass, and the upper limit of the content of the transparent polymer layer relative to the total amount of the transparent polymer layer and the liquid crystal composition may be 70% by mass, more preferably 60% by mass.

[0031] The lower and upper limits of the content of the transparent polymer layer are within a range in which the liquid crystal particles of the liquid crystal composition phase-separate from the cured product of the photopolymerizable compound during the curing process of the photopolymerizable compound. When it is necessary to increase the mechanical strength of the transparent polymer layer, it is preferable that the lower limit of the content of the transparent polymer layer is high. When it is necessary to reduce the driving voltage of the liquid crystal molecules, it is preferable that the upper limit of the content of the transparent polymer layer is low.

[0032] In this embodiment, the liquid crystal composition may contain a dichroic dye. The dichroic dye has an elongated shape. The absorbance in the visible region in the long axis direction of the dichroic dye molecule is greater than the absorbance in the visible region in the short axis direction of the molecule. The dichroic dye is nearly transparent when the long axis direction is parallel or approximately parallel to the incident direction of light. In contrast, the dichroic dye exhibits a predetermined color when the long axis direction is perpendicular or approximately perpendicular to the incident direction of light.

[0033] Therefore, the dichroic dye exhibits transparency when oriented such that its long axis direction is parallel or approximately parallel to the normal direction of the contact surface of the switchable layer with the first transparent electrode layer 21 and the contact surface of the switchable layer 23 with the second transparent electrode layer 22. In contrast, the dichroic dye exhibits a predetermined color when oriented such that its long axis direction is perpendicular or approximately perpendicular to the normal direction of the contact surface of the switchable layer 23 with the first transparent electrode layer 21 and the contact surface of the switchable layer 23 with the second transparent electrode layer 22. The color exhibited by the dichroic dye is preferably black or a color close to black. The dichroic dye is driven by a guest-host system using liquid crystal molecules as a host, thereby causing the dichroic dye to exhibit color.

[0034] The dichroic dye may be at least one selected from the group consisting of polyiodine, azo compounds, anthraquinone compounds, naphthoquinone compounds, azomethine compounds, tetrazine compounds, quinophthalone compounds, merocyanine compounds, perylene compounds, and dioxazine compounds. The dichroic dye may be one type of dye or a combination of two or more types of dyes. From the viewpoint of improving the light fastness of the dichroic dye and increasing the dichroic ratio, the dichroic dye is preferably at least one selected from the group consisting of azo compounds and anthraquinone compounds. The dichroic dye is more preferably an azo compound. The liquid crystal composition may contain, in addition to the liquid crystal molecules and dichroic dye, a monomer for forming a transparent polymer layer, for example.

[0035] The material forming each of the transparent substrates 24, 25 may be a synthetic resin or an inorganic compound. Examples of synthetic resins include polyester, polyacrylate, polycarbonate, and polyolefin. Examples of polyesters include polyethylene terephthalate and polyethylene naphthalate. Examples of polyacrylates include polymethyl methacrylate. Examples of inorganic compounds include silicon dioxide, silicon oxynitride, and silicon nitride. The thickness of each of the transparent substrates 24, 25 may be, for example, 250 μm or less.

[0036] Each of the electrodes 21E, 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 made of insulating synthetic resin. The support layer and the protective layer are made of, for example, polyimide. The conductor portion is made of, for example, a metal thin film. The material that forms the metal thin film may be, for example, copper. Each of the electrodes 21E, 22E is not limited to an FPC, and may be, for example, a metal tape.

[0037] Each of the electrodes 21E and 22E is attached to the corresponding transparent electrode layer 21 and 22 by a conductive adhesive layer (not shown). In each of the electrodes 21E and 22E, the conductor portion is exposed from the protective layer or the support layer at the portion connected to the conductive adhesive layer.

[0038] The conductive adhesive layer may be formed of, for example, an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), an isotropic conductive film (ICF), an isotropic conductive paste (ICP), etc. From the viewpoint of ease of handling in the manufacturing process of the first dimming device 10N, the conductive adhesive layer is preferably an anisotropic conductive film. Each of the wirings 26 is formed of, for example, a metal wire and an insulating layer covering the metal wire. The wire is formed of, for example, copper.

[0039] The driving unit 12 applies an AC voltage between the first transparent electrode layer 21 and the second transparent electrode layer 22. The driving unit 12 preferably applies an AC voltage having a rectangular waveform between the pair of transparent electrode layers 21 and 22. In other words, the driving unit 12 preferably outputs a voltage signal having a rectangular wave.

[0040] When no voltage is applied to the light-controlling layer 23, the liquid crystal molecules have no particular order in the orientation of their long axes. That is, the liquid crystal molecules are randomly oriented within the voids. This makes the light-controlling layer 23, and therefore the first light-controlling sheet 11N, opaque when no voltage is applied to the light-controlling layer 23. In other words, the first light-controlling sheet 11N has a relatively high haze value.

[0041] When a voltage is applied to the light-controlling layer 23, the liquid crystal molecules are aligned parallel to the electric field. The first light-controlling sheet 11N is configured so that when a voltage is applied to the light-controlling layer 23, the long axis direction of the liquid crystal molecules is perpendicular to the contact surface. In other words, the liquid crystal molecules are aligned vertically. Therefore, the light-controlling layer 23, and therefore the first light-controlling sheet 11N, is transparent when a voltage is applied to the light-controlling layer 23. As a result, the first light-controlling sheet 11N has a relatively low haze value.

[0042] [Optical properties of the first light-controlling sheet] The first dimming device 10N satisfies the following conditions 1-1 to 1-4. (Condition 1-1) The haze of the first light controlling sheet 11N when the drive unit 12 applies the first voltage VN1 to the first light controlling sheet 11N is 80% or more.

[0043] (Condition 1-2) The haze of the first light controlling sheet 11N when the drive unit 12 applies the second voltage VN2 to the first light controlling sheet 11N is less than 10%. (Condition 1-3) In the first light-controlling sheet 11N, the brightness index L when the second voltage VN2 is applied and when the third voltage VN3 is applied * The difference value is 20 or more.

[0044] (Condition 1-4) In the first light controlling sheet 11N, the color coordinate a when the second voltage VN2 is applied and when the third voltage VN3 is applied * The difference value of is 15 or more, or the color coordinate b * The difference value is 20 or more.

[0045] The driver 12 applies a first voltage VN1, a second voltage VN2, and a third voltage VN3 to the first light controlling sheet 11N. At the first voltage VN1, the potential difference between the first transparent electrode layer 21 and the second transparent electrode layer 22 is zero, and the third voltage VN3 is between the first voltage VN1 and the second voltage VN2. When the first voltage VN1 is applied to the first light controlling sheet 11N, the first light controlling sheet 11N appears opaque. When the second voltage VN2 is applied to the first light controlling sheet 11N, the first light controlling sheet 11N appears transparent. When the third voltage VN3 is applied to the first light controlling sheet 11N, the first light controlling sheet 11N appears intermediate between transparent and opaque.

[0046] The haze value of the first light-modulating sheet 11N is determined by a method conforming to JIS K 7136:2000 "Plastics - Determination of Haze." * , color coordinate a * , and color coordinate b * JIS Z 8781-4:2013 "Colorimetry - Part 4: CIE 1976L * a * b * It is calculated by a method that conforms to the "color space".

[0047] Since the first light control device 10N satisfies the conditions 1-1 to 1-4, applying the third voltage VN3 to the first light control sheet 11N makes the light darker than when the second voltage VN2 is applied, and the color coordinate a * or color coordinate b * In this case, the first light controlling sheet 11N can exhibit a color different from that when the second voltage VN2 is applied.

[0048] Furthermore, according to the first light adjusting device 10N of the present disclosure, the first light adjusting sheet 11N can exhibit a color different from that exhibited when the second voltage VN2 is applied, even if the liquid crystal composition does not contain a dichroic dye. Therefore, no color change occurs due to photodecomposition of the dichroic dye, and light-induced fading of the first light adjusting sheet 11N can be suppressed.

[0049] The first dimming device 10N may further satisfy at least one of the following conditions: That is, the first dimming device 10N may satisfy Condition 1-5 or Condition 1-6 described below, or may satisfy both Condition 1-5 and Condition 1-6.

[0050] (Condition 1-5) In the first light-controlling sheet 11N, the brightness index L when the second voltage is applied and when the first voltage is applied * The difference between the color coordinates a when the second voltage is applied and the color coordinate a when the first voltage is applied is 90 or more. * The difference between the color coordinates b * The difference value is 3.0 or less.

[0051] (Condition 1-6) In the first light controlling sheet 11N, the color coordinate a * and color coordinate b * has a maximum value at a voltage having a magnitude between the first voltage and the second voltage.

[0052] By the first light control device 10N satisfying conditions 1-5, when the second voltage VN2 is applied to the first light control sheet 11N, the first light control sheet 11N can be brighter than when the first voltage VN1 is applied, while the first light control sheet 11N can exhibit a color that is less different from the color exhibited by the first light control sheet 11N when the first voltage VN1 is applied. Furthermore, by the first light control device 10N satisfying conditions 1-6, each color coordinate a * ,b * By applying a voltage at which a maximum value is exhibited to the first light controlling sheet 11N, any one of the color coordinates a * ,b * In this case, it is possible to maximize the deviation of the color exhibited by the first light-controlling sheet 11N from the color exhibited by the first light-controlling sheet 11N when the first voltage VN1 or the second voltage VN2 is applied to the first light-controlling sheet 11N.

[0053] In addition, the color coordinate a * and color coordinate b *The voltage value at which the voltage V r has a maximum value may be the same as or different from the third voltage VR3.

[0054] [Second dimmer] As shown in FIG. 2, the second light control device 10R includes a reverse-type second light control sheet 11R and a drive unit 12. In addition to the layers included in the first light control sheet 11N, the second light control sheet 11R includes a first alignment layer 27 and a second alignment layer 28. The light control layer 23 is located between the first alignment layer 27 and the second alignment layer 28. The first alignment layer 27 is located between the light control layer 23 and the first transparent electrode layer 21 and is in contact with the light control layer 23. The second alignment layer 28 is located between the light control layer 23 and the second transparent electrode layer 22 and is in contact with the light control layer 23.

[0055] The materials for forming the first alignment layer 27 and the second alignment layer 28 are organic compounds, inorganic compounds, and mixtures thereof. Examples of organic compounds include polyimide, polyamide, polyvinyl alcohol, and cyanide compounds. Examples of inorganic compounds include silicon oxide and zirconium oxide. The material for forming the alignment layers 27 and 28 may be silicone. Silicone is a compound having both inorganic and organic portions.

[0056] The first alignment layer 27 and the second alignment layer 28 are, for example, vertical alignment layers. The vertical alignment layer aligns the long axis direction of the liquid crystal molecules so that it is perpendicular to the surface opposite to the surface in contact with the first transparent electrode layer 21 and the surface opposite to the surface in contact with the second transparent electrode layer 22. In this way, the alignment layers 27 and 28 regulate the orientation of the multiple liquid crystal molecules contained in the light control layer 23.

[0057] Like the light control layer 23 of the first light control sheet 11N, the light control layer 23 includes a transparent polymer layer with voids and a liquid crystal composition filled in the voids. The liquid crystal composition includes liquid crystal molecules. The liquid crystal composition includes negative nematic liquid crystals with negative dielectric anisotropy as the liquid crystal molecules. Like the liquid crystal composition of the first light control sheet 11N, the liquid crystal composition may include at least one of a dichroic dye and a monomer.

[0058] When no voltage is applied to the light control layer 23, the liquid crystal molecules are aligned perpendicular to the contact surface due to the alignment restricting force of the alignment layers 27 and 28. Therefore, the light control layer 23, and therefore the second light control sheet 11R, is transparent when no voltage is applied to the light control layer 23. This allows the second light control sheet 11R to have a relatively low haze value.

[0059] When a voltage is applied to the light-controlling layer 23, the liquid crystal molecules are aligned perpendicular to the electric field. The second light-controlling sheet 11R is configured so that when a voltage is applied to the light-controlling layer 23, the long axis direction of the liquid crystal molecules is parallel to the contact surface. In other words, the liquid crystal molecules are aligned horizontally. Therefore, the light-controlling layer 23, and therefore the second light-controlling sheet 11R, is opaque when a voltage is applied to the light-controlling layer 23. This gives the second light-controlling sheet 11R a relatively high haze value.

[0060] [Optical properties of the second light-controlling sheet] The second light control device 10R satisfies the following conditions 2-1 to 2-4. (Condition 2-1) The haze of the second light controlling sheet 11R is 80% or more when the first voltage VR1 is applied, and the first voltage VR1 is the minimum voltage value at which the haze of the second light controlling sheet 11R is 80% or more.

[0061] (Condition 2-2) The haze of the second light controlling sheet 11R when the second voltage VR2 is applied is 15% or less. (Condition 2-3) The brightness index L when the second voltage VR2 is applied and when the third voltage VR3 is applied * The difference value is 20 or more.

[0062] (Condition 2-4) Color coordinate a when the second voltage VR2 is applied and when the third voltage VR3 is applied * The difference value of is 15 or more, or the color coordinate b * The difference value is 20 or more.

[0063] The driver 12 applies a first voltage VR1, a second voltage VR2, and a third voltage VR3 to the second light control sheet 11R. At the second voltage VR2, the potential difference between the first transparent electrode layer 21 and the second transparent electrode layer 22 is zero, and the third voltage VR3 has a magnitude between the first voltage VR1 and the second voltage VR2. When the first voltage VR1 is applied to the first light control sheet 11N, the first light control sheet 11N appears opaque. When the second voltage VR2 is applied to the first light control sheet 11N, the first light control sheet 11N appears transparent. When the third voltage VR3 is applied to the first light control sheet 11N, the first light control sheet 11N appears intermediate between transparent and opaque.

[0064] The haze value of the second light-modulating sheet 11R is determined by a method conforming to JIS K 7136:2000 "Plastics - Determination of Haze." * , color coordinate a * , and color coordinate b * JIS Z 8781-4:2013 "Colorimetry - Part 4: CIE 1976L * a * b * It is calculated by a method that conforms to the "color space".

[0065] By applying the third voltage VR3 to the second light controlling sheet 11R, the light becomes darker than when the second voltage VR2 is applied, and the color coordinate a * or color coordinate b * In this case, the second light adjusting sheet 11R can exhibit a color different from that when the second voltage VR2 is applied. Furthermore, according to the second light adjusting device 10R of the present disclosure, the second light adjusting sheet 11R can exhibit a color different from that when the second voltage VR2 is applied, even if the liquid crystal composition does not contain a dichroic dye. Therefore, no color change occurs due to photodecomposition of the dichroic dye, and it is possible to suppress fading of the second light adjusting sheet 11R due to light.

[0066] The second dimming device 10R may further satisfy at least one of the following conditions: That is, the second dimming device 10R may satisfy Condition 2-5 or Condition 2-6 described below, or may satisfy both Condition 2-5 and Condition 2-6.

[0067] (Condition 2-5) Color coordinate b when the second voltage VR2 is applied and when the third voltage VR3 is applied * The difference value is 30 or more. (Condition 2-6) Color coordinate b when the second voltage VR2 is applied and when the third voltage VR3 is applied * The difference between the first voltage VR1 and the second voltage VR2 is 20 or more, and the brightness index L * The difference between the color coordinates b * The difference value is 20 or more.

[0068] By making the second light adjusting device 10R satisfy condition 2-5, when the third voltage VR3 is applied to the second light adjusting sheet 11R, the second light adjusting sheet 11R can exhibit a color that is significantly different from when the second voltage VR2 is applied to the second light adjusting sheet 11R. Furthermore, by making the second light adjusting device 10R satisfy condition 2-6, when the second voltage VR2 and the third voltage VR3 are applied to the second light adjusting sheet 11R, the second light adjusting sheet 11R can exhibit a color that is different from when the first voltage VR1 is applied.

[0069] [Example] [Example 1-1] An acrylate compound was prepared as a monomer for forming a transparent polymer layer. Furthermore, several types of positive nematic liquid crystals represented by the following formulas (1) to (12) were used as liquid crystal molecules. The refractive index anisotropy Δn of the mixture of liquid crystal molecules was adjusted to 1.6. A coating liquid containing 50 parts by mass of liquid crystal molecules and 50 parts by mass of monomer was then prepared. In the chemical formulas listed below, R1 and R2 are independently an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkenyloxy group having 2 to 12 carbon atoms, an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen atom is replaced by fluorine or chlorine, fluorine, or a cyano group.

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[0082] Two transparent films were prepared, each comprising a 20 nm thick ITO layer and a 125 μm thick polyethylene terephthalate film. A coating solution was applied to the ITO layer of one of the transparent films to form a coating film with a thickness of 10 μm after curing. The ITO layer of the other transparent film was then brought into contact with the coating film. This sandwiched the coating film between the pair of transparent films.

[0083] A pair of ultraviolet lamps was then placed so as to sandwich the pair of transparent films, and the coating film was then irradiated with ultraviolet light using the pair of lamps. At this time, the intensity of the ultraviolet light was 10 mW / cm 2 The temperature was set to 100°C, and the UV irradiation time was set to 100 seconds. UV irradiation caused phase separation in the coating film, forming a light-control layer with an average void diameter of 0.5 μm. As a result, a first light-control sheet included in the light-control device of Example 1-1 was obtained.

[0084] [Comparative Example 1-1] In Example 1-1, the first light-controlling sheet provided in the light-controlling device of Comparative Example 1-1 was obtained by the same method as in Example 1-1, except that the coating liquid was changed to contain 30 parts by mass of liquid crystal molecules and 70 parts by mass of monomer.

[0085] [Comparative Example 1-2] In Example 1-1, the intensity of the ultraviolet light was 1 mW / cm 2 The first light-control sheet provided in the light-control device of Comparative Example 1-2 was obtained in the same manner as in Example 1-1, except that the temperature was set to 100°C and the light-control layer had an average void diameter of 5.5 μm.

[0086] [Example 2-1] An acrylate compound was prepared as a monomer for forming a transparent polymer layer. Liquid crystal molecules were selected from the negative nematic liquid crystals shown in formulas (13) to (23) below. The refractive index anisotropy Δn of the mixture of liquid crystal molecules was adjusted to 1.6. A coating liquid containing 50 parts by mass of liquid crystal molecules and 50 parts by mass of the monomer was then prepared. In the chemical formulas listed below, R1 and R2 are independently an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkenyloxy group having 2 to 12 carbon atoms, or an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen atom is replaced by fluorine or chlorine.

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[0098] Two transparent films were prepared, each consisting of a 20 nm thick ITO layer and a 125 μm thick polyethylene terephthalate film. A 100 nm thick polyimide alignment layer was formed on each ITO layer.

[0099] The coating liquid was applied onto the alignment layer of one of the transparent films so as to form a coating film with a thickness of 5 μm after curing, and then the alignment layer of the other transparent film was brought into contact with the coating film, thereby sandwiching the coating film between the pair of transparent films.

[0100] A pair of ultraviolet lamps was then placed so as to sandwich the pair of transparent films, and the coating film was then irradiated with ultraviolet light using the pair of lamps. At this time, the intensity of the ultraviolet light was 10 mW / cm 2 The temperature was set to 100°C, and the UV irradiation time was set to 100 seconds. UV irradiation caused phase separation in the coating film, forming a light-control layer with an average void diameter of 2 μm. As a result, a second light-control sheet included in the light-control device of Example 2-1 was obtained.

[0101] [Example 2-2] In Example 2-1, the first light-controlling sheet provided in the light-controlling device of Example 2-2 was obtained in the same manner as in Example 2-1, except that the coating film was formed by applying the coating liquid so that the thickness after curing was 10 μm.

[0102] [Example 2-3] In Example 2-1, the intensity of the ultraviolet light was 20 mW / cm 2 A first light-controlling sheet to be provided in the light-controlling device of Example 2-3 was obtained in the same manner as in Example 2-1, except that the average void diameter was changed to 1.5 μm.

[0103] [Comparative Example 2-1] In Example 2-1, a coating liquid containing 30 parts by mass of liquid crystal molecules and 70 parts by mass of monomers was prepared, and the intensity of ultraviolet light was set to 5 mW / cm 2 and the average void diameter was changed to 5.5 μm, and a first light-controlling sheet to be provided in the light-controlling device of Comparative Example 2-1 was obtained in the same manner as in Example 2-1.

[0104] [Evaluation method] The optical properties of the light-controlling sheet installed in each light-control device were evaluated when three or more different driving voltages were applied. * b * Lightness index L in color space * and color coordinate a * ,b *As described above, the haze value was determined by a method conforming to JIS K 7136:2000 "Plastics - Determination of haze", and the yellowness index YI was determined by a method conforming to JIS Z 8781-4:2013 "Colorimetry - Part 4: CIE 1976L * a * b * The brightness index L is calculated using a method that conforms to the "Color Space" * and color coordinate a * ,b * The yellowness index (YI) was also determined by a method in accordance with JIS K 7373:2006 "Plastics - Determination of yellowness index and yellowing index."

[0105] The haze value was measured using a haze meter (NDH7000(II), manufactured by Nippon Denshoku Industries Co., Ltd.). * , color coordinate a * ,b * When determining the color and yellowness index YI, a spectrophotometer (U-4100, manufactured by Hitachi High-Technologies Corporation) was used.

[0106] In Example 1-1 and Comparative Example 1-1, the yellowing index ΔYI and the brightness difference ΔL were calculated based on the values ​​when the driving voltage was 100 V. * , color coordinate difference Δa * ,Δb * In Comparative Example 1-2, the yellowing index ΔYI and the brightness difference ΔL were calculated based on the values ​​when the driving voltage was 48 V. * , color coordinate difference Δa * ,Δb * In Example 2-1, Example 2-2, Comparative Example 2-1, and Comparative Example 2-2, the yellowing index ΔYI and the brightness difference ΔL were calculated based on the respective values ​​when the driving voltage was 0 V. * , color coordinate difference Δa * ,Δb * was calculated.

[0107] [Evaluation results] The evaluation results of each example and each comparative example will be described with reference to Figures 3 to 10. Each figure shows the evaluation results of the drive voltage applied to the light-adjusting sheet provided in each light-adjusting device and the optical characteristics of the light-adjusting sheet. Also, Figure 4 shows the evaluation results for the light-adjusting device of Example 1-1, Figure 5 shows the evaluation results for Comparative Example 1-1, and Figure 6 shows the evaluation results for Comparative Example 1-2. Figure 7 shows the evaluation results for the light-adjusting device of Example 2-1, Figure 8 shows the evaluation results for the light-adjusting device of Example 2-2, Figure 9 shows the evaluation results for the light-adjusting device of Example 2-3, and Figure 10 shows the evaluation results for the light-adjusting device of Comparative Example 2-1.

[0108] Figure 3 shows the L * a * b * 1 shows a schematic representation of a color space. As Figure 3 shows, L * a * b * In color space, the lightness index L * As the value approaches 100, the color of the object approaches white W, while the lightness index L * The closer to 0, the closer the object's color is to black BK. * In the color coordinates b, the more positive the value, the closer it is to red (R), and the more negative the value, the closer it is to green (G). * In the example, the more positive the value, the closer it is to yellow Y, and the more negative the value, the closer it is to blue BL.

[0109] As shown in FIG. 4, in the light control device of Example 1-1, when the driving voltage is 18 V, the brightness difference ΔL * is 45.3, and the color coordinate difference Δb * It was found that the color coordinate a * When the driving voltage is 18 V, the color coordinate b * It was also found that the brightness difference ΔL when the driving voltage was 0 V * is 91.5, while the color coordinate difference Δa *is -1.0 and the color coordinate difference Δb * was found to be 2.7.

[0110] In contrast, as shown in FIG. 5, in the light control device of Comparative Example 1-1, the first light control sheet * is 20 or more, and the color coordinate difference Δa * is 15 or more, or the color coordinate difference Δb * It was found that the driving voltage did not satisfy the requirement that the value of .gtoreq.20 be 20 or more.

[0111] In addition, as shown in FIG. 6, in the light control device of Comparative Example 1-2, the first light control sheet * is 20 or more, and the color coordinate difference Δa * is 15 or more, or the color coordinate difference Δb * It was found that the driving voltage did not satisfy the requirement that the value of .gtoreq.20 be 20 or more.

[0112] As shown in FIG. 7, in the light control device of Example 2-1, when the driving voltage is 12 V, the lightness difference ΔL * is 44.7, and the color coordinate difference Δa * It was confirmed that the brightness difference ΔL was 16.4 when the driving voltage was 24 V in the second light-control sheet. * is 45.9, and the color coordinate difference Δb * is 31.2 and the driving voltage is 48V, the brightness difference ΔL * is 45.2, and the color coordinate difference Δb * was found to be 32.7.

[0113] As shown in FIG. 8, in the light control device of Example 2-2, when the driving voltage is 48 V, the lightness difference ΔL * is 24.0, and the color coordinate difference Δb * It was found that the difference in brightness ΔL was −25.3. * is 26.5, and the color coordinate difference Δb * was found to be -28.7.

[0114] As shown in FIG. 9, in the light control device of Example 2-3, when the driving voltage is 48 V, the lightness difference ΔL * is 33.2, and the color coordinate difference Δb * It was found that the difference in brightness ΔL was −31.5. * is 41.8, and the color coordinate difference Δb * is -37.5 and the driving voltage is 135V, the brightness difference ΔL * is 43.0, and the color coordinate difference Δb * was found to be -28.0.

[0115] As shown in FIG. 10, in the light control device of Comparative Example 2-1, the second light control sheet * is 20 or more, and the color coordinate difference Δa * is 15 or more, or the color coordinate difference Δb * It was found that the driving voltage did not satisfy the requirement that the value of .gtoreq.20 be 20 or more.

[0116] As described above, according to one embodiment of the light control device, the following effects can be obtained. (1) By applying the third voltage VN3 to the first light controlling sheet 11N, the light becomes darker than when the second voltage VN2 is applied, and the color coordinate a * or color coordinate b * In this case, the first light controlling sheet 11N can exhibit a color different from that when the second voltage VN2 is applied.

[0117] (2) When the second voltage VN2 is applied to the first light-adjusting sheet 11N, the first light-adjusting sheet 11N can be made brighter than when the first voltage VN1 is applied, while still allowing the first light-adjusting sheet 11N to exhibit a color that is only slightly different from the color exhibited by the first light-adjusting sheet 11N when the first voltage VN1 is applied.

[0118] (3) Each color coordinate a * ,b *By applying a voltage at which a maximum value is exhibited to the first light controlling sheet 11N, any one of the color coordinates a * ,b * In this case, it is possible to maximize the deviation of the color exhibited by the first light-controlling sheet 11N from the color exhibited by the first light-controlling sheet 11N when the first voltage VN1 or the second voltage VN2 is applied to the first light-controlling sheet 11N.

[0119] (4) By applying the third voltage VR3 to the second light controlling sheet 11R, the light becomes darker than when the second voltage VR2 is applied, and the color coordinate a * or color coordinate b * In this state, the second light controlling sheet 11R can exhibit a color different from that when the second voltage VR2 is applied.

[0120] (5) When the third voltage VR3 is applied to the second light-controlling sheet 11R, the second light-controlling sheet 11R can exhibit a color that is more significantly different from when the second voltage VR2 is applied to the second light-controlling sheet 11R.

[0121] (6) The second light-controlling sheet 11R can exhibit a different color when the second voltage VR2 and the third voltage VR3 are applied to the second light-controlling sheet 11R than when the first voltage VR1 is applied.

[0122] The above-described embodiment can be modified as follows. [Control Unit] The light control device controls the brightness difference ΔL between the light control sheets 11N and 11R. * and the color coordinate difference Δa * ,Δb * The control unit may further include a control unit that changes the brightness difference ΔL between different levels. The control unit controls the driving of the drive unit 12 that the light control devices 10N and 10R include. * The control unit may include information such as a table for converting the brightness difference ΔL specified by an external operation device into a driving voltage. * The drive unit applies a drive voltage corresponding to the

[0123] Alternatively, the control unit may set different color coordinate differences Δa * The color coordinate difference Δa * Alternatively, the control unit applies a driving voltage corresponding to the color coordinate difference Δb * The color coordinate difference Δb * The drive unit applies a drive voltage corresponding to the

[0124] According to the light control device including these control units, the lightness difference ΔL of the light control sheets 11N and 11R desired by the user of the light control devices 10N and 10R can be * , or color coordinate difference Δa * ,Δb * The appearance of the light controlling sheets 11N and 11R can be controlled depending on the light controlling sheet.

[0125] [Note] The technical ideas derived from the above-described embodiment and modifications are described below. [Appendix 1] a first transparent electrode layer; A second transparent electrode layer; a light-controlling layer located between the first transparent electrode layer and the second transparent electrode layer, the light-controlling layer including a transparent polymer layer having a plurality of voids, and a liquid crystal composition filled in the voids; the haze of the light-controlling sheet is 80% or more when a first voltage is applied such that the potential difference between the first transparent electrode layer and the second transparent electrode layer is zero; The haze of the light-controlling sheet when a second voltage is applied is less than 10%; The brightness index L when the second voltage is applied and when a third voltage having a magnitude between the first voltage and the second voltage is applied * The difference value is 20 or more, The color coordinates a when the second voltage is applied and when the third voltage is applied are * The difference value of is 15 or more, or the color coordinate b *The difference value is 20 or more. Dimming sheet.

[0126] [Appendix 2] a first transparent electrode layer; A second transparent electrode layer; a light-controlling layer located between the first transparent electrode layer and the second transparent electrode layer, the light-controlling layer including a transparent polymer layer having a plurality of voids and a liquid crystal composition filled in the voids; a first alignment layer located between the first transparent electrode layer and the light control layer; a second alignment layer located between the second transparent electrode layer and the light control layer, The haze of the light-controlling sheet is 80% or more when a first voltage is applied, and the first voltage is the minimum voltage value at which the haze of the light-controlling sheet is 80% or more; the haze of the light-controlling sheet is 15% or less when a second voltage is applied such that the potential difference between the first transparent electrode layer and the second transparent electrode layer is zero; The brightness index L when the second voltage is applied and when a third voltage having a magnitude between the first voltage and the second voltage is applied * The difference value is 20 or more, The color coordinates a when the second voltage is applied and when the third voltage is applied are * The difference value of is 15 or more, or the color coordinate b * The difference value is 20 or more. Dimming sheet.

[0127] According to the light-controlling sheet of Supplementary Notes 1 and 2, by applying the third voltage to the light-controlling sheet, the light becomes darker than when the second voltage is applied, and the color coordinate a * or color coordinate b * When the second voltage is applied, the light-controlling sheet can exhibit a color different from that when the first voltage is applied. [Explanation of symbols]

[0128] 10N…1st dimmer 10R…Second dimmer 11N...First light control sheet 11R...2nd photochromic sheet 21...First transparent electrode layer 22...Second transparent electrode layer 23...Photochromic layer 27...First alignment layer 28...Second alignment layer

Claims

1. a light control sheet including a light control layer including a first transparent electrode layer, a second transparent electrode layer, a transparent polymer layer positioned between the first transparent electrode layer and the second transparent electrode layer and including a plurality of voids, and a liquid crystal composition filled in the voids; a drive unit that applies a voltage to the light controlling sheet, the driving unit applies a first voltage, a second voltage, and a third voltage to the light-controlling sheet, the first voltage being a voltage difference between the first transparent electrode layer and the second transparent electrode layer being zero, and the third voltage being a voltage between the first voltage and the second voltage; The haze of the light-controlling sheet when the first voltage is applied is 80% or more, and the haze of the light-controlling sheet when the second voltage is applied is less than 10%; In the light-controlling sheet, the brightness index L when the second voltage is applied and when the third voltage is applied ＊ the difference between the color coordinates a when the second voltage is applied and the color coordinates a when the third voltage is applied is 20 or more, ＊ The difference value of 15 or more, or the color coordinate b ＊ The difference value is 20 or more. Dimmer.

2. In the light-controlling sheet, The brightness index L when the second voltage is applied and when the first voltage is applied ＊ The difference value is 90 or more, The color coordinate a when the second voltage is applied and when the first voltage is applied ＊ The difference value is 1.5 or less, The color coordinate b when the second voltage is applied and when the first voltage is applied ＊ The difference value is 3.0 or less. The light control device according to claim 1 .

3. In the light-adjusting sheet, the color coordinate a ＊ and the color coordinate b ＊ has a maximum value at a voltage having a magnitude between the first voltage and the second voltage The light control device according to claim 1 or 2.

4. a light-controlling sheet including: a first transparent electrode layer, a second transparent electrode layer; a light-controlling layer located between the first transparent electrode layer and the second transparent electrode layer and including a transparent polymer layer having a plurality of voids and a liquid crystal composition filled in the voids; a first alignment layer located between the first transparent electrode layer and the light-controlling layer; and a second alignment layer located between the second transparent electrode layer and the light-controlling layer; a drive unit that applies a voltage to the light controlling sheet, the driving unit applies a first voltage, a second voltage, and a third voltage to the light-controlling sheet, the second voltage causing a potential difference between the first transparent electrode layer and the second transparent electrode layer to be zero, and the third voltage having a magnitude between the first voltage and the second voltage; The haze of the light-controlling sheet when the first voltage is applied is 80% or more, and the first voltage is the minimum voltage value at which the haze of the light-controlling sheet is 80% or more, the haze of the light-controlling sheet when the second voltage is applied is 15% or less; In the light-controlling sheet, the brightness index L when the second voltage is applied and when the third voltage is applied ＊ the difference between the color coordinates a when the second voltage is applied and the color coordinates a when the third voltage is applied is 20 or more, ＊ The difference value of 15 or more, or the color coordinate b ＊ The difference value is 20 or more. Dimmer.

5. In the light-controlling sheet, the color coordinates b ＊ The difference value is 30 or more. The light control device according to claim 4 .

6. In the light-controlling sheet, Color coordinates b when the second voltage is applied and when the third voltage is applied ＊ The difference value is 20 or more, The brightness index L when the second voltage is applied and when the first voltage is applied ＊ The difference value is 20 or more, Color coordinates b when the second voltage is applied and when the first voltage is applied ＊ The difference value is 20 or more. The light control device according to claim 4 or 5.

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