Liquid crystal light control element

Abstract

This invention provides a liquid crystal light control element with which it is possible to achieve both an antiglare function and a heat generation suppression function. According to an embodiment, this liquid crystal light control element is characterized in that: the element includes a pair of transparent electrode substrates having a transparent electrode layer, and a light control layer disposed inside the transparent electrode substrates and containing liquid crystal molecules; the light control layer contains a dichroic dye; and the visible light transmittance of the transparent electrode substrates is 89% or less, and the visible light reflectance of the transparent electrode substrates is 6.5% or more.

Description

Liquid crystal dimming element

[0001] This invention relates to a liquid crystal dimming element.

[0002] Patent Document 1 discloses an invention relating to a light-adjustable film equipped with a polymer-dispersed liquid crystal layer. The transparent conductive layer includes a light-transmitting resin and anisotropic conductive fibers.

[0003] Japanese Patent Publication No. 2021-60521

[0004] No technology has been established that simultaneously satisfies the requirements for preventing glare from sunlight and preventing heat generation caused by sunlight. This invention has been made in view of this matter, and aims to provide a liquid crystal dimming element that can achieve both glare prevention and heat generation suppression functions.

[0005] The liquid crystal dimming element of this embodiment comprises a pair of transparent electrode substrates having a transparent electrode layer, and a dimming layer disposed inside the transparent electrode substrates and containing liquid crystal molecules, wherein the dimming layer contains a dichroic dye, the visible light transmittance of the transparent electrode substrates is 89% or less, and the visible light reflectance of the transparent electrode substrates is 6.5% or more.

[0006] Alternatively, the liquid crystal dimming element of this embodiment comprises a pair of transparent electrode substrates having a transparent electrode layer, and a dimming layer disposed inside the transparent electrode substrates and containing liquid crystal molecules, wherein the dimming layer contains a dichroic dye, and the transparent electrode substrates contain silver or a silver alloy.

[0007] Alternatively, the liquid crystal dimming element of this embodiment is a liquid crystal dimming element comprising a pair of transparent electrode substrates having a transparent electrode layer, and a dimming layer disposed inside the transparent electrode substrates and containing liquid crystal molecules, wherein the dimming layer contains a dichroic dye, and the visible light transmittance of the liquid crystal dimming element when light is blocked is 4% or less.

[0008] According to the present invention, by including a dichroic dye in the photochromic layer, controlling the visible light transmittance and visible light reflectance of the transparent electrode substrate, and including silver or a silver alloy in the transparent electrode layer, it is possible to simultaneously solve the problems of preventing glare from sunlight and preventing heat generation caused by sunlight.

[0009] This is a schematic cross-sectional view of the liquid crystal dimming element of this embodiment.

[0010] The embodiments of the present invention will be described in detail below, but the following description is merely an example (representative example) of the embodiments described herein, and the present invention is not limited to these contents unless it exceeds the gist of the invention. Also, the notation "~" includes lower and upper limits.

[0011] <Configuration of the Liquid Crystal Light-Damping Element 10> Figure 1 is a schematic cross-sectional view of the liquid crystal light-dampening element 10 of this embodiment. As shown in Figure 1, the liquid crystal light-dampening element 10 has a laminated structure comprising a pair of transparent substrates 1, a transparent electrode layer 2 formed on the inside of each transparent substrate 1, and a light-dampening layer 3 formed on the inside of each transparent electrode layer 2. "Inside" refers to the opposing sides.

[0012] In other words, the liquid crystal dimming element 10 is stacked from bottom to top in the following order: transparent substrate 1 (first transparent substrate), transparent electrode layer 2 (first transparent electrode layer), dimming layer 3, transparent electrode layer 2 (second transparent electrode layer), and transparent substrate (second transparent substrate) 1.

[0013] (Transparent electrode substrate 4) The transparent electrode substrate 4 is composed of the transparent substrate 1 and the transparent electrode layer 2 shown in Figure 1. The transparent electrode substrate 4 is in the form of a film. The term "film" refers to a planar shape in which the width and length of the plane are significantly larger than the thickness, but it can also be read as "sheet". In this embodiment, the distinction between "film" and "sheet" is not made based on the thickness specified in the JIS standard.

[0014] The material of the transparent substrate 1 is not limited, but a PET (Polyethylene Terephthalate) film is preferably used. The transparent electrode layer 2 is a transparent conductive layer that utilizes the conductivity of metal and contains silver (Ag) or a silver alloy.

[0015] While not limiting the film thickness, the transparent substrate 1 is approximately 50 μm to 200 μm thick, and the transparent electrode layer 2 is approximately 10 μm to 100 μm thick.

[0016] Furthermore, the transparent electrode substrate 4 may have a functional layer provided between the transparent substrate 1 and the transparent electrode layer 2, or on at least one of the outer surfaces located outside the transparent substrate 1 (the surface opposite to the side facing the transparent electrode layer 2). The functional layer preferably includes at least one of the following: a hard coat layer, an antiblocking layer, a primer layer, a protective layer, or an index matching layer.

[0017] (Light-adjusting layer 3) The light-adjusting layer 3 contains a liquid crystal composition. The light-adjusting layer 3 is assumed to be composed of, for example, polymer dispersed liquid crystal (PDLC), but may also be composed of polymer network liquid crystal (PNLC), nematic curvilinear aligned phase (NCAP), etc. For example, polymer dispersed liquid crystal and polymer network liquid crystal have a polymer network having a three-dimensional mesh structure, and liquid crystal molecules are held in the voids of the polymer network. The liquid crystal molecules contained in the light-adjusting layer 3 have, for example, positive dielectric anisotropy, and the dielectric constant in the long axis direction of the liquid crystal molecule is greater than the dielectric constant in the short axis direction of the liquid crystal molecule. Examples of liquid crystal molecules are Schiff base-based, azo-based, azoxy-based, biphenyl-based, terphenyl-based, benzoic acid ester-based, tran-based, pyrimidine-based, cyclohexanecarboxylic acid ester-based, phenylcyclohexane-based, and dioxane-based liquid crystal molecules.

[0018] The dimming layer 3 of this embodiment contains a dichroic dye. In this embodiment, the color when light is blocked (opaque state) can be set to black (so-called black dimming), thereby absorbing scattered light and suppressing whitening caused by scattered light. For example, it is possible to realize a dimming device (dimming sheet, dimming film) with a wide viewing angle suitable for car interiors and living spaces.

[0019] Furthermore, in this embodiment, it is preferable that the light-adjusting layer 3 includes black spacers (black functional fine particles). This allows for high functionality in combination with the dichroic dye contained in the light-adjusting layer 3 (due to the synergistic effect of the dichroic dye and the black spacers). More specifically, within the light-adjusting layer, scattered light is absorbed by the dichroic dye and the black spacers, thus achieving high light-shielding properties in an opaque state.

[0020] <Background to the Liquid Crystal Dimming Element 10 of this Embodiment> As described above, a dimming device using a dimming layer made of a liquid crystal composition containing a dichroic dye can achieve high light-shielding properties in an opaque state and can be applied to windows of structures for purposes such as protecting privacy and controlling the entry of energy into buildings.

[0021] In recent years, these dimming devices have been considered for outdoor use in structures and for applications in automobile windows and sunroofs. Such applications require measures to prevent glare from sunlight and to mitigate heat generation caused by sunlight.

[0022] In addressing glare from sunlight, it is necessary to reduce the total light transmittance of the light-adjusting layer when it is shading. For this purpose, for example, laminating smoked glass onto a light-adjusting film has been considered. However, smoked glass raises concerns about heat absorption by the glass itself and the resulting thermal cracking. Furthermore, since measures to counter heat generated by sunlight are also required, simply laminating smoked glass makes it difficult to simultaneously solve both the problem of glare from sunlight and the problem of heat generated by sunlight.

[0023] Thus, dimming technology that simultaneously addresses both glare prevention from sunlight and heat generation caused by sunlight has not yet been established, which has been a major obstacle to practical application.

[0024] Therefore, as a result of diligent research, the inventors have invented a liquid crystal dimming element that can simultaneously establish anti-glare and heat-suppressing functions by including a dichroic dye in the dimming layer, controlling the visible light transmittance and visible light reflectance of the transparent electrode substrate, and including silver or a silver alloy in the transparent electrode layer.

[0025] <Features of the liquid crystal dimming element 10 of this embodiment> The liquid crystal dimming element 10 of this embodiment is characterized by containing a dichroic dye in the dimming layer, adjusting the visible light transmittance and visible light reflectance of the transparent electrode substrate, and containing silver or a silver alloy in the transparent electrode layer.

[0026] According to this embodiment, in addition to the light absorption by the dichroic dye contained in the light-adjusting layer, the light absorption and reflection effects of the transparent electrode substrate are added, making it possible to lower the transmittance of the liquid crystal light-adjusting element to a lower value than expected when light is blocked.

[0027] "Lower than expected" means that, when compared to a case where ITO is used as the transparent electrode layer, the result obtained is lower than the expected value.

[0028] That is, if the visible light transmittance of the transparent electrode substrate in this embodiment is A, and the visible light transmittance of the transparent electrode substrate in the comparative example (using ITO for the transparent electrode layer) is B, then the transmittance ratio of the liquid crystal dimming element in this embodiment to that of the comparative example is (A ２ / B ２ ) is assumed, but in reality, the transmittance ratio in this embodiment is the assumed value (A ２ / B ２ It was found to be below the expected value. The reason why A and B were squared to obtain the transmittances for this embodiment and the comparative example is that, as shown in Figure 1, a pair of transparent electrode substrates 4 are provided. We will now consider the reason why it is below the expected value.

[0029] When light is blocked, the light-adjusting layer scatters light, and the dichroic dye contained in the light-adjusting layer absorbs the scattered light. At this time, scattered light that is not absorbed by the dichroic dye is incident on the transparent electrode substrate on the light-emitting side at various angles, but incident light exceeding the total reflection angle is reflected off the surface of the transparent electrode substrate on the light-emitting side and returned to the light-adjusting layer, where it is absorbed by the dichroic dye. This reflection characteristic can be made greater than in the comparative example using ITO. Also, light absorption at the transparent electrode substrate can be made higher compared to the comparative example using ITO. As a result, the transmittance ratio of the liquid crystal light-adjusting element in this embodiment compared to the comparative example can be set to the assumed value (A ２ / B ２ It is thought that this can be made smaller.

[0030] In this embodiment, the light absorption of the dichroic dye and the light absorption and reflection effects of the transparent electrode substrate can simultaneously solve the problems of preventing glare from sunlight and preventing heat generation caused by sunlight.

[0031] In this embodiment, the visible light transmittance of the transparent electrode substrate is 89% or less, and the visible light reflectance of the transparent electrode substrate is 6.5% or more. As a result, the visible light transmittance of the transparent electrode substrate can be reduced and the visible light reflectance of the transparent electrode substrate can be increased compared to the comparative example using ITO. Accordingly, the transmittance ratio of the liquid crystal dimming element in this embodiment to the comparative example is set to the assumed value (A ２ / B ２ It can be made smaller and achieve both anti-glare and heat-suppressing functions.

[0032] Visible light transmittance is determined, for example, by measuring transmittance in the visible light region using a UH-4150 (manufactured by Hitachi High-Tech) within the measurement wavelength range of 380 nm to 1550 nm, and then determining the average transmittance in that region.

[0033] Furthermore, the visible light reflectance can be measured by a method compliant with JIS R3106:2019. Light is shone onto the surface of the transparent electrode substrate 4 at an incident angle of 90°. The visible light reflectance can then be measured based on the specular reflection of the incident light. The visible light reflectance is calculated in accordance with JIS R3106:2019 by irradiating the substrate with light containing wavelengths from 380 nm to 780 nm and using spectral data acquired at 10 nm intervals from 380 nm to 780 nm.

[0034] In this embodiment, the visible light transmittance of the transparent electrode substrate 4 is preferably 88% or less, more preferably 87% or less, and even more preferably 86% or less.

[0035] Furthermore, the visible light transmittance of the transparent electrode substrate 4 is preferably 30% or more, preferably 40% or more, more preferably 45% or more, even more preferably 50% or more, even more preferably 55% or more, even more preferably 60% or more, and most preferably 70% or more.

[0036] Further, the visible light reflectance of the transparent electrode substrate 4 is preferably 6.6% or more, more preferably 6.7% or more, and even more preferably 6.8% or more.

[0037] Further, considering the balance with the visible light transmittance, the visible light reflectance of the transparent electrode substrate 4 can be 15% or less, 13% or less, 10% or less, 9% or less, or 8% or less. As a result, compared with the comparative example using ITO, the visible light transmittance of the transparent electrode substrate can be more effectively reduced, and the visible light reflectance of the transparent electrode substrate can be increased.

[0038] In this embodiment, measurement errors of the visible light transmittance and the visible light reflectance are tolerated. Since the film thickness of the transparent electrode substrate 4 is quite thin, a reflectance width of about ±1% can be provided.

[0039] Further, in this embodiment, the transparent electrode layer is characterized by containing silver (Ag) or an Ag alloy. Although not limited, for example, the transparent electrode layer is a metal mesh formed by arranging Ag wires in a matrix on a transparent substrate, a transparent conductive film formed by applying and printing an ink composition in which Ag particles or Ag wires are mixed in ink on a transparent substrate, or an Ag thin film substrate formed by uniformly sputtering or depositing an Ag thin film on the surface of a transparent substrate.

[0040] Thus, by forming a metal layer containing silver or a silver alloy as the transparent electrode layer, transparency and good conductivity are ensured, and the light absorption and reflection effects in the transparent electrode substrate can be enhanced compared to the case of using ITO. As a result, the anti-glare measure against sunlight and the heat generation measure due to sunlight can be solved simultaneously.

[0041] In the transparent electrode substrate provided with a transparent electrode layer containing silver or a silver alloy, the visible light transmittance of the transparent electrode substrate can be accurately reduced to 89% or less, and the visible light reflectance of the transparent electrode substrate can be 6.5% or more.

[0042] Furthermore, this embodiment is characterized in that the visible light transmittance of the liquid crystal dimming element when light is blocked is 4% or less. This makes it possible to reduce the visible light transmittance compared to when ITO is used for the transparent electrode layer, and to have excellent light-blocking properties. In this embodiment, it is preferable that the visible light transmittance of the liquid crystal dimming element when light is blocked is 3.7% or less, and more preferably 3.5% or less.

[0043] Furthermore, while a lower visible light transmittance of the liquid crystal dimming element when light is blocked is desirable, it is actually difficult to achieve 0%. Therefore, if we were to indicate a lower limit, it could be 0.1% or higher, 0.5% or higher, 1.0% or higher, 1.5% or higher, and 2.0% or higher.

[0044] In this embodiment, the visible light transmittance of the transparent electrode substrate is 89% or less, the visible light reflectance of the transparent electrode substrate is 6.5% or more, and by using silver or a silver alloy in the transparent electrode layer, the visible light transmittance of the liquid crystal dimming element when light is blocked can be precisely adjusted to 4% or less.

[0045] Furthermore, in this embodiment, it is preferable that the transmittance of the liquid crystal dimming element at a wavelength of 850 nm when light is blocked is 60% or less, and the transmittance at a wavelength of 1550 nm is 50% or less. In this embodiment, compared to the case in which ITO is used for the transparent electrode layer, the transmittance in the near-infrared and infrared regions can be significantly reduced, and a high heat shielding effect can be obtained.

[0046] In this embodiment, the transmittance at a wavelength of 850 nm is more preferably 50% or less, even more preferably 45% or less, and even more preferably 40% or less. While not limiting the lower limit, the transmittance at 850 nm can be 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, and 30% or more. Furthermore, the transmittance at a wavelength of 1550 nm is more preferably 40% or less, even more preferably 30% or less, even more preferably 20% or less, and even more preferably 15% or less. Again, while not limiting the lower limit, the transmittance at 1550 nm can be 1% or more, 3% or more, 5% or more, 7% or more, and even more preferably 10% or more. In this embodiment, compared to the case where ITO is used for the transparent electrode layer, the transmittance at 850 nm and the transmittance at 1550 nm can be reduced by 10% or more, preferably 15% or more, and more preferably 20% or more.

[0047] According to the liquid crystal dimming element and the device using the same of this embodiment, for example, there is no need to laminate smoked glass as a measure against glare from sunlight, and both glare from sunlight and heat generation from sunlight can be solved simultaneously, so it can be preferably applied to outdoor applications of structures, as well as to automobile windows and sunroofs.

[0048] The present invention will be described in detail below with reference to examples taken to clarify its effects. However, the present invention is not limited in any way by the following examples.

[0049] <About the material composition of the light-adjusting layer> First, let's explain the material composition used in the light-adjusting layer. Liquid crystal A shown in Table 1 is a composition mainly composed of cyano-based liquid crystal compounds and fluorine-based liquid crystal compounds, and is a nematic liquid crystal composition with positive dielectric anisotropy (Δε>0).

[0050] Furthermore, a dichroic dye was used as a mixed black dye of azo and anthraquinone types (a three-color mixture of YMC), and the amount added was 2.5% by mass (wt%).

[0051] Also, the monomer composition B shown in Table 1 is a monomer composition obtained by appropriately mixing monomers such as polyfunctional acrylate / methacrylate, monofunctional acrylate, and urethane acrylate. The liquid crystal ratios shown in Table 1 indicate the mixing ratios of liquid crystal A and monomer composition B.

[0052]

[0053] <Regarding the transparent electrode substrate> In Examples 1 to 3, a transparent electrode substrate obtained by sputtering an Ag thin film uniformly on the surface of a PET substrate was used. In the comparative example, a transparent electrode substrate having an ITO film uniformly formed on the surface of a PET substrate was used.

[0054] In Examples 1, 3, and the comparative example, a PET film was used as the transparent substrate. On the other hand, in Example 2, polycarbonate (PC) was used as the transparent substrate. The surface resistance values of Examples 1 and 2 were 10 Ω / sq, the surface resistance value of Example 3 was 4 Ω / sq, and the surface resistance value of the comparative example was 100 Ω / sq. Note that it is common to control the sputtered film thickness by the surface resistance value ρs (ρs = ρ / t, ρ: resistivity, t: film thickness).

[0055] <Regarding the structure of the liquid crystal dimming element> A coating liquid obtained by appropriately mixing a photopolymerization initiator and black spacers with the liquid crystal A, monomer composition B, and a mixture of dichroic dyes shown in Table 1 was laminated on the transparent electrode substrates of the examples and the comparative example, and exposed to UV light (center wavelength 360 nm) with respect to the laminated structure of transparent electrode substrate / dimming layer / transparent electrode substrate. The exposure conditions were set to 2 to 12 mW / cm ２ as set.

[0056] <Measurement of visible light transmittance and visible light reflectance> The visible light transmittance of the transparent electrode substrates in Examples 1 to 3 and the comparative example, and further, the visible light transmittance of the liquid crystal dimming elements in Examples 1 to 3 and the comparative example were measured.

[0057] The visible light transmittance was defined as the average value of the transmittance in the visible light region when the transmittance was measured within the range of measurement wavelengths of 380 nm to 1550 nm using, for example, UH-4150 (manufactured by Hitachi High-Tech). The results are shown in Table 2.

[0058]

[0059] As shown in Table 2, the visible light transmittance of the transparent electrode substrate in Example 1 was 85.9%, the visible light transmittance of the transparent electrode substrate in Example 2 was 81.0%, the visible light transmittance of the transparent electrode substrate in Example 3 was 49.0%, and the visible light transmittance of the transparent electrode substrate in which the transparent electrode layer was formed with ITO was 89.6%.

[0060] Furthermore, the visible light transmittance of the liquid crystal dimming element in Example 1 when shielded from light was 3.4%, the visible light transmittance of the liquid crystal dimming element in Example 2 was 3.1%, the visible light transmittance of the liquid crystal dimming element in Example 1 was 1.2%, and the visible light transmittance of the liquid crystal dimming element in the comparative example was 4.1%.

[0061] As shown in Table 2, the transmittance of the liquid crystal dimming element in the example where the transparent electrode substrate was formed with an Ag thin film was found to be lower than that of the comparative example where ITO was used for the transparent electrode layer.

[0062] <Assumed values ​​for transmittance ratio> As shown in Table 3 below, if we let A be the visible light transmittance of the transparent electrode substrate using Ag thin film (each example) and B be the visible light transmittance of the transparent electrode substrate using ITO (example), then from Table 1, A in Example 1 is 85.9% and B is 89.6%. Therefore, the transmittance ratio (A / B) of the electrode substrate alone in Example 1 was approximately 0.96. The same calculation was performed for Examples 2 and 3.

[0063]

[0064] Table 3 shows (electrode substrate only). ２ That is, (A ２ ) / (B ２ It can be calculated as follows. The reason for squaring is that transparent electrode substrates are present above and below the dimming layer. (Electrode substrate alone) in Example 1 ２ The transmittance ratio was approximately 0.92. The same procedure was followed for Examples 2 and 3.

[0065] The transmittance ratio of the liquid crystal dimming elements shown in Table 3 is calculated by taking the visible light transmittance of the liquid crystal dimming elements in each example as C and the visible light transmittance of the liquid crystal dimming elements in the comparative example as D. From Table 2, C for Example 1 is 3.43% and D is 4.09%, so the transmittance ratio (C / D) of the liquid crystal dimming element in Example 1 was approximately 0.84. The same calculation was performed for Examples 2 and 3. Thus, it was found that Examples 1 to 3 transmit less light than the comparative example. Table 4 shows the visible light reflectance of Examples 1 to 3 using Ag thin films and the visible light reflectance of the comparative example using ITO.

[0066]

[0067] The visible light reflectance was measured according to the method compliant with JIS R3106:2019. As shown in Table 4, the reflective effect of the Ag thin films in Examples 1 to 3 was found to be higher than that of the ITO in the comparative example.

[0068] The transmittance ratio (C / D) of the liquid crystal dimming element shown in Table 3 should ideally be (electrode substrate alone). ２ While it was predicted that the transmittance ratio would be approximately the same as the predicted value, in Example 1, the transmittance ratio (C / D) of the liquid crystal dimming element was 0.84, which was lower than the predicted value (0.92). In Examples 2 and 3, the values ​​were also lower than the predicted values.

[0069] As previously explained, this is thought to be due to improved light shielding properties resulting from the light absorption and reflection effects of the transparent electrode substrate using the Ag thin film, in addition to the light absorption of the dichroic dye.

[0070] <Transmittance in the Near-Infrared and Infrared Regions> Next, the transmittance of the liquid crystal dimming elements of Examples 1 to 3 and the Comparative Example in the near-infrared and infrared regions was measured and compared. Near-infrared and infrared light transmittance is defined as the average value of the transmittance in the near-infrared and infrared regions when the transmittance is measured within the range of measurement wavelengths from 380 nm to 1550 nm using, for example, a UH-4150 (manufactured by Hitachi High-Tech). Table 5 shows the transmittance of the liquid crystal dimming elements of the Examples and Comparative Example in the near-infrared and infrared regions.

[0071]

[0072] As shown in Table 5, the liquid crystal dimming elements of Examples 1 to 3 showed a significantly lower transmittance in the near-infrared and infrared regions compared to the comparative example, indicating that a high heat shielding effect could be achieved.

[0073] The experimental results above show that light-shielding and heat-shielding properties can be simultaneously ensured by the light absorption of the dichroic dye and the light absorption and reflection effects of the transparent electrode layer of the Ag thin film. Therefore, it was found that by using the liquid crystal dimming element of this embodiment, it is possible to simultaneously solve the problems of preventing glare from sunlight and the problem of heat generation caused by sunlight.

[0074] This application is based on Japanese Patent Application No. 2024-165976, filed on September 25, 2024. All of its contents are included here.

Claims

1. A liquid crystal dimming element comprising: a pair of transparent electrode substrates having a transparent electrode layer; a dimming layer disposed inside the transparent electrode substrates and containing liquid crystal molecules, wherein the dimming layer contains a dichroic dye; the visible light transmittance of the transparent electrode substrates is 89% or less; and the visible light reflectance of the transparent electrode substrates is 6.5% or more.

2. The liquid crystal dimming element according to claim 1, characterized in that the visible light transmittance of the transparent electrode substrate is 86% or less.

3. The liquid crystal dimming element according to claim 1, characterized in that the visible light reflectance of the light electrode substrate is 6.8% or more.

4. The liquid crystal dimming element according to claim 1, characterized in that the transmittance of the liquid crystal dimming element at a wavelength of 850 nm when light is blocked is 60% or less, and the transmittance at a wavelength of 1550 nm is 50% or less.

5. The liquid crystal dimming element according to claim 1, characterized in that the dimming layer further includes a black spacer.

6. A liquid crystal dimming element comprising a pair of transparent electrode substrates having a transparent electrode layer, and a dimming layer disposed inside the transparent electrode substrates and containing liquid crystal molecules, wherein the dimming layer contains a dichroic dye, and the transparent electrode substrates contain silver or a silver alloy.

7. The liquid crystal dimming element according to claim 6, characterized in that the transparent electrode substrate has a silver thin film formed on its surface.

8. The liquid crystal dimming element according to claim 6, characterized in that the transparent electrode layer is a metal mesh formed in a matrix of silver wires on a transparent substrate, or a transparent conductive film obtained by coating or printing an ink composition in which silver particles or silver wires are mixed in ink onto a transparent substrate.

9. The liquid crystal dimming element according to claim 6, characterized in that the dimming layer further includes a black spacer.

10. A liquid crystal dimming element comprising a pair of transparent electrode substrates having a transparent electrode layer, and a dimming layer disposed inside the transparent electrode substrates and containing liquid crystal molecules, wherein the dimming layer contains a dichroic dye, and the visible light transmittance of the liquid crystal dimming element when light is blocked is 4% or less.

11. The liquid crystal dimming element according to claim 10, characterized in that the visible light transmittance of the liquid crystal dimming element when light is blocked is 3.5% or less.

12. The liquid crystal dimming element according to claim 10, characterized in that the dimming layer further includes a black spacer.

Images