JPH0525479A - Light intensity regulating element - Google Patents

Abstract

PURPOSE:To provide a light intensity regulating element excellent in the performance of controlling transmission of visible or infrared rays. CONSTITUTION:The objective light intensity regulating element composed by sandwiching a light intensity regulating material comprising a liquid crystal and a polymer, and controlling the transmission and scattering of light according to the presence or absence of an applied electric field between a pair of electrode plates each containing an electrode in its inside. An electrode having an ability to reflect infrared rays is formed inside at least either of a pair of the electrode plates. This element excels in the performance of controlling transmittance to light in the range of visible to infrared rays. Therefore, it can provide a comfortable cabin or a comfortable living environment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dimming element, and more particularly to a dimming element having excellent transmission control performance for light in a wide range.

[0002]

2. Description of the Related Art A light control material composed of liquid crystal and a polymer holding it is in a cloudy state because incident light is scattered due to a difference between the refractive index of the polymer and that of the liquid crystal when no electric field is applied. In addition, when an electric field is applied, the liquid crystal aligns in the direction of the electric field, and the refractive index of the polymer and the refractive index of the liquid crystal are close to each other. Wake up.

Conventionally, a light control element utilizing such a property is disclosed in, for example, Japanese Patent Laid-Open No. 64-62615, Japanese Patent Publication No.
No. 3-501512 and Japanese Patent Publication No. 58-501631.

[0004]

However, although the light control elements described above and can control the transmission of visible light, it is difficult to control the transmission of near infrared light or infrared light. In recent years, in order to obtain a comfortable living environment and in-vehicle environment, it is expected to control the transmission of sunlight by a light control element, but sunlight contains about 50% near infrared or infrared light. Therefore, the conventional dimming element in which the control of the transmission of these light is insufficient cannot obtain the function capable of sufficiently achieving the purpose.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a light control element having excellent controllability of transmission of visible light or infrared light in a wide range.

[0006]

A light control element according to claim 1 is
A dimming device comprising a liquid crystal and a polymer, which controls the transmission and scattering of light depending on whether an electric field is applied or not, is sandwiched between a pair of electrode substrates having electrodes on an inner surface, At least one of the pair of electrode substrates is formed with an electrode having infrared reflectivity.

A light control element according to a second aspect is the light control element according to the first aspect, wherein the electrode having infrared reflectivity is gold, silver,
It is characterized by being one or more metal thin films selected from the group consisting of copper, palladium and aluminum, or a laminated film thereof.

A dimmer element according to a third aspect is the dimmer element according to the first aspect, wherein the electrode having infrared reflectivity is selected from the group consisting of an indium tin oxide thin film and gold, silver, copper, palladium and aluminum. It is characterized in that it is a laminated film with one or more kinds of metal thin films.

A dimmer element according to a fourth aspect is the dimmer element according to the third aspect, wherein the electrode having infrared reflectivity is a laminated film in which a gold thin film is laminated on an indium tin oxide thin film. And

The light control element of claim 5 is the light control element of claim 1, wherein the electrode having infrared reflectivity is gold, silver,
At least one metal thin film selected from the group consisting of copper, palladium and aluminum or a laminated film thereof, and titanium,
Bismuth, indium, tin, cerium, tantalum, tungsten, molybdenum, erbium, hafnium,
Dielectric thin films composed of oxides and / or sulfides of at least one metal selected from the group consisting of zinc, yttrium, zirconium, silicon, antimony, lead, scandium and aluminum are alternately laminated in three or more layers. It is a laminated film of

A dimmer element according to a sixth aspect is the dimmer element according to the fifth aspect, wherein the electrode having infrared reflectivity is a laminated film in which a silver thin film is sandwiched from both sides by a titanium oxide thin film. .

The present invention will be described in detail below. The light control material containing the liquid crystal and the polymer of the present invention can be produced, for example, by the following methods (a) to (d). (A) An impregnation method of impregnating a polymer porous body with liquid crystal. (B) An emulsification method in which a liquid crystal is emulsified into fine droplets in an aqueous solution of a water-soluble polymer and then cast on a substrate having a transparent electrode. (C) A solvent casting method in which a liquid crystal and a polymer are dissolved in their common solvent and then cast. (D) A liquid in which a uniform solution of a liquid crystal and a prepolymer of a polymer holding the liquid crystal (a general term for substances (eg, monomers) before being polymerized) is prepared, and this is subjected to phase separation by polymerization to form a phase separation structure. legal.

The proportion of liquid crystal in the light control material thus obtained is preferably 5 to 95% by weight,
More preferably, it is 40 to 95% by weight, and the liquid crystal used may be one selected from the group consisting of nematic liquid crystal, smectic liquid crystal and cholesteric liquid crystal, or a mixture thereof.

On the other hand, as the polymer which holds these liquid crystals, specifically, vinyl compounds such as polyethylene, polyacrylic acid, polyacrylic acid ester, polyvinyl acetate, polyacrylonitrile, polyvinyl chloride, polyvinyl fluoride and vinyl are used. Compound addition polymer, polymethacrylic acid, polymethacrylic acid ester, polyvinylidene chloride,
Polyvinylidene fluoride, vinylidene cyanide, vinylidene fluoride / trifluoroethylene copolymer, vinylidene fluoride / tetrafluoroethylene copolymer, vinylidene cyanide / vinyl acetate copolymer, etc. Vinyl compound or fluorine compound copolymer , Compounds containing fluorine such as polytrifluoroethylene, polytetrafluoroethylene, polyhexafluoropropylene, nylon 6, nylon 66
Etc. Polyamide, polyimide, polyurethane, polypeptide, polyester such as polyethylene terephthalate, polycarbonate, polyoxymethylene, polyethylene oxide, polyether such as polypropylene oxide, epoxy resin, polyvinyl alcohol, polyvinyl butyral and the like. These polymers may be used alone or in appropriate combination of two or more.

The dimming material according to the present invention includes, if necessary, anthraquinone-based, azo-based, quinophthalone-based dichroic dyes, surfactants, stabilizers such as ultraviolet absorbers and antioxidants, A chain transfer agent, a photosensitizer, a cross-linking agent, etc. can be added.

The light control element of the present invention is a pair of substrates having electrodes on the inner surface thereof using the light control material of the present invention, at least one of which has infrared reflectivity. It is manufactured by being sandwiched between the electrode substrates which are the ones.

In the present invention, at least one of the electrodes formed on the pair of substrates has infrared reflectivity. However, if both electrodes have infrared reflectivity, the transmittance decreases, The other is preferably a transparent electrode having no infrared reflectivity. In this case, a transparent electrode such as a metal oxide represented by ITO (indium tin oxide) is used as the transparent electrode, and a transparent substrate such as glass or plastic such as polyester is used as the electrode substrate. .

Examples of the electrode having infrared reflectivity include the following. At least one metal thin film selected from the group consisting of gold, silver, copper, palladium and aluminum, or a laminated film thereof. A laminated film of an ITO thin film and one or more metal thin films selected from the group consisting of gold, silver, copper, palladium and aluminum. Among these, a laminated film in which a gold thin film is laminated on an ITO thin film is preferable. One or more metal thin films selected from the group consisting of gold, silver, copper, palladium and aluminum, or laminated films thereof, and titanium, bismuth, indium, tin, cerium, tantalum, tungsten, molybdenum, erbium, hafnium, zinc , Yttrium, zirconium,
A laminated film in which three or more layers of dielectric thin films such as oxides and / or sulfides made of one or more metals selected from the group consisting of silicon, antimony, lead, scandium and aluminum are alternately laminated.

The following are typical examples of the structure of the laminated film. TiO ₂ / Ag / TiO ₂ , B
i ₂ O ₃ / Au / Bi ₂ O ₃ , SiO ₂ / Au / SiO
₂ , SiO ₂ / Ag / SiO ₂ , SnO ₂ / Cu / Sn
O ₂ , In ₂ O ₃ /Au.Ag/In ₂ O ₃ , In ₂ O
₃ / Ag · Cu / In ₂ O ₃ , TiO ₂ / Ag · Cu /
TiO ₂ , ITO / Ag / ITO, ITO / Ag / Ti
O ₂ , ZrO ₂ / Ag / ZrO ₂ , ZnS / Ag / Zn
S, Ag / TiO ₂ / Ag, Au / Bi ₂ O ₃ / Au,
Au / SiO ₂ / Au, Ag / SiO ₂ / Ag, Ag /
ITO / Ag, Ag / ZnS / Ag, TiO ₂ / Ag /
TiO ₂ / Ag. Of these, TiO ₂ / Ag / TiO ₂
, SnO ₂ / Cu / SnO ₂ , In ₂ O ₃ / Au · A
g / In ₂ O _{3 and the} like are more preferable.

Further, Na ₃ AlF ₆ was used as the dielectric thin film, and Ag / Na ₃ AlF ₆ / A was laminated with the silver thin film.
g, Ag / Na ₃ AlF ₆ / Ag / Na ₃ AlF ₆ / A
A composite laminated film such as g or a laminated film obtained by laminating the above-mentioned dielectric films may also be used as the infrared reflective electrode.

The metal thin films in the above items 1 to 3 can be formed by vacuum vapor deposition or sputtering, and the film thickness thereof is preferably in the range of 20 to 1000Å, particularly 50 to 300Å. The metal oxide thin film or the dielectric thin film in, can be formed by vacuum deposition, sputtering or chemical coating, and the film thickness is preferably in the range of 20 to 1000Å, particularly 50 to 500Å.

In addition, the thin film or laminated film having infrared reflectivity as described above and, which is adhered to a transparent substrate such as glass or plastic such as polyester with an adhesive, is used as an electrode having infrared reflectivity. You can also

The above items 1 to 3 are examples of the electrode having infrared reflectivity. The transparent electrode made of a metal oxide typified by ITO is used, and the electrode surface and / or the substrate surface has the infrared reflectivity. It is also possible to use an electrode formed by laminating. Therefore, a thin film or a laminated film having infrared reflectivity as described above and is adhered to a substrate surface of a transparent electrode of a metal oxide typified by ITO with an adhesive to be used as an electrode having infrared reflectivity. You can also In this case, when the electrode having infrared reflectivity is laminated on the substrate surface side, durability such as scratch resistance becomes a problem, so it is necessary to provide a protective film on the electrode having infrared reflectivity. It is preferable to stack the reflective electrode on the electrode surface side.

When a protective film is required, the protective film may be an organic film of acrylic resin, polyacrylonitrile, polypropylene, polyimide or the like, or one of metal oxides such as titanium, silica and aluminum. Examples of the thin film include the oxide or the mixed oxide of two or more kinds.

The dimming device of the present invention can be used as a transmissive dimming device when a pair of transparent electrode substrates are used as substrates, one of which is transparent and the other of which is opaque. In this case, by placing a reflective layer after the opaque electrode substrate, it can be used as a reflective dimming device.

[0026]

In the light control element of the present invention, since at least one of the pair of electrode substrates is provided with an electrode having infrared reflectivity, it is possible to control transmission of visible light or infrared light in a wide range. Excellent performance. Since the light control material according to the present invention has good film formation uniformity, it is more excellent due to the above effects. In particular, as the electrode having infrared reflectivity, the electrodes of claims 2, 3, and 5, and especially the electrodes of claims 4 and 6 are suitable.

[0027]

EXAMPLES Next, the present invention will be described more specifically by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Example 1 An ITO film having a thickness of 250 Å was formed on each of two 125 μm-thick polyethylene terephthalate films, one of which was used as a transparent electrode plate. And for the other,
Further, a gold film having a thickness of 75 μm was laminated on the ITO film by vapor deposition to form an infrared reflecting electrode plate. Between the two electrode plates (ITO film side is the inside), 0.05 g of trimethylolpropane triacrylate, 0.1 g of n-butyl acrylate, and biphenyl nematic liquid crystal E-8 (B).
DH) 0.35 g, 2,2-dimethoxy-2-phenylacetophenone 0.003 g which is a polymerization initiator, and a plastic (divinylbenzene copolymer) spacer 0.008 g having a diameter of 10 μm. By inserting it and exposing it with an ultraviolet irradiation device, a uniform light control element without cracks or the like was obtained. The applied energy corresponds to 800 mJ.

The solar radiation transmittance (JIS R310) when a voltage is not applied to the obtained light control element (OFF) and when an alternating current of 100 V (60 Hz, sine wave) is applied (ON).
Measured by the method described in 6. Indicates the degree of sunlight penetration. ) And visible light transmittance (measured by the method described in JIS R3106) were measured, and the results are shown in Table 1.

Example 2 On a polyethylene terephthalate film having a thickness of 75 μm, a titanium oxide film having a thickness of 200 Å and a silver film having a thickness of 150 are formed.
A titanium oxide film having a thickness of 300 Å was sequentially laminated by sputtering to prepare an infrared reflecting electrode plate. This infrared reflective electrode plate and I prepared in the same manner as in Example 1
The liquid mixture prepared in Example 1 was inserted between the transparent electrode plate made of polyethylene terephthalate with TO (each having the film side as the inner side), and then treated under the same conditions as in Example 1 to obtain a light control element. Was produced. About the obtained light control element, Example 1
The solar radiation transmittance and the visible light transmittance were measured in the same manner as in, and the results are shown in Table 1.

Example 3 On a polyethylene terephthalate film having a thickness of 50 μm, a titanium oxide film having a thickness of 200 Å and a silver film having a thickness of 140 are formed.
A titanium oxide film having a thickness of 280 Å was sequentially deposited on the Å by sputtering. A 75 μm-thick polyethylene terephthalate film was adhered to the polyethylene terephthalate surface of this laminated film with an acrylic adhesive for strength reinforcement to prepare an infrared reflective electrode plate. After inserting the mixed solution prepared in Example 1 between the electrode side of the infrared reflecting electrode plate and the ITO film side of the transparent electrode plate of polyethylene terephthalate with ITO prepared in the same manner as in Example 1, A dimming device was produced by processing under the same conditions as in Example 1. With respect to the obtained light control device, the solar radiation transmittance and the visible light transmittance were measured in the same manner as in Example 1, and the results are shown in Table 1.

Example 4 On a polyethylene terephthalate film having a thickness of 125 μm, an ITO film having a thickness of 250 Å was formed by sputtering to prepare two transparent electrode plates. The liquid mixture prepared in Example 1 was inserted between the two transparent electrode plates (each having ITO inside), and then the mixture was treated under the same conditions as in Example 1 to prepare a light control device.

On one side of the polyethylene terephthalate film of this light control element, the laminated film prepared in Example 3 (titanium oxide film 200Å thickness, silver film 140Å thickness,
A polyethylene terephthalate surface side of a titanium oxide film having a thickness of 280Å which was sequentially laminated on a polyethylene terephthalate film) was overlaid and adhered with an acrylic adhesive to manufacture a light control element. For the obtained light control device, the solar radiation transmittance and the visible light transmittance were measured in the same manner as in Example 1,
The results are shown in Table 1.

Comparative Example 1 In Example 1, except that the gold thin film was not laminated.
The same processing as in Example 1 was carried out to produce a light control element, and the optical characteristics were measured in the same manner. The results are shown in Table 1.

[0035]

[Table 1]

As is clear from Table 1, in the light control element of the present invention, the visible light transmittance can be controlled while controlling the solar radiation transmittance to be low. In particular, Examples 2 and 3
In the cases of 4 and 4, while suppressing the solar radiation transmittance when the electric field is OFF to around 50%, that is, reducing the transmission of sunlight to half, the electric field O
The visible light transmittance at the time of N can be made as bright as about 70%.

[0037]

As described in detail above, the light control element of the present invention has excellent controllability of transmission of visible light or infrared light in a wide range and is used as a high characteristic light control element used for a light control window or a display device. It is extremely useful industrially.

Claims (6)

[Claims] 1. A light control material comprising a liquid crystal and a polymer, which is sandwiched between a pair of electrode substrates each having an electrode on its inner surface, and a light control material which controls transmission / scattering of light depending on whether or not an electric field is applied. In the optical element, an electrode having infrared reflectivity is formed on at least one of the pair of electrode substrates. 2. The electrode having infrared reflectivity is gold, silver,
The light control element according to claim 1, which is one or more metal thin films selected from the group consisting of copper, palladium and aluminum, or a laminated film thereof. 3. The infrared reflective electrode is a laminated film of an indium tin oxide thin film and one or more metal thin films selected from the group consisting of gold, silver, copper, palladium and aluminum. 1. The light control element according to 1. 4. The light control device according to claim 3, wherein the electrode having infrared reflectivity is a laminated film in which a gold thin film is laminated on an indium tin oxide thin film. 5. The electrode having infrared reflectivity is gold, silver,
At least one metal thin film selected from the group consisting of copper, palladium and aluminum or a laminated film thereof, and titanium,
Bismuth, indium, tin, cerium, tantalum, tungsten, molybdenum, erbium, hafnium,
Dielectric thin films composed of oxides and / or sulfides of at least one metal selected from the group consisting of zinc, yttrium, zirconium, silicon, antimony, lead, scandium and aluminum are alternately laminated in three or more layers. The dimming element according to claim 1, which is a laminated film comprising: 6. The light control device according to claim 5, wherein the electrode having infrared reflectivity is a laminated film in which a silver thin film is sandwiched by thin films of titanium oxide from both sides.