JPH0618939A - Light control sheet - Google Patents

Abstract

PURPOSE:To provide the light control sheet which is highly flexible, is lightweight and is easier to handle by constituting electrode plates of electrode films provided with thin-film electrode layers and thermally melt-sticking these electrode films to each other at the ends thereof. CONSTITUTION:A liquid crystal or electrolyte 3 is held between the electrode films formed by providing on the synthetic resin substrate films 4 with the thin-film electrode layers (transparent electrode thin films 1 or these films and electrode thin films 2) and the ends of a pair of the electrode films holding the liquid crystal are sealed by thermally melt-sticking. Only the transparent electrode thin films 1 are usually used as the thin-film electrode layers if the orientation of the liquid crystal is utilized. The two-layered structure films 1, 2 are used as the thin-film electrode layers if the electrolyte is used by utilizing an electrochromic effect. Since the resin films 4 are used in place of glass, the light control sheet is highly flexible, lightweight and easy to handle. The films are stuck to each other by thermally melt-sticking without using adhesives and, therefore, the production process is simplified and the various defects occurring in the adhesives are averted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light control sheet having a light control function capable of reversibly changing the light transmittance by applying a voltage.

[0002]

2. Description of the Related Art Recently, attempts have been made to utilize a dimming function capable of electrochemically reversibly changing the light transmittance. It is well known that such a light control function is based on a method using an electrochromy effect, a method using alignment of liquid crystal, and the like. In the method using the electrochromy effect, ITO is conventionally formed on a glass substrate.
A transparent electrode / electrode thin film having a two-layer structure is used, an electrolyte solution is sandwiched between these glass substrates, and an edge portion of the glass substrate is sealed with an adhesive. Even when the liquid crystal is used, a structure is used in which the liquid crystal is sandwiched by using glass substrates provided with transparent electrodes, and the glass substrates are also sealed with an adhesive. In either case, as the adhesive, a photo-curing type, a thermosetting type, a hot-melt resin or the like such as an epoxy resin or an acrylic resin is often used.

[0003]

However, in the structure using the above-mentioned glass substrate, the shape of the glass is fixed and heavy, and the glass is easily broken, so that there is a problem in handling. Further, when the glass substrate is sealed with the adhesive as described above, the liquid electrochromic substance is deteriorated and deteriorated by the solvent of the adhesive, and the spots of the adhesive adhere to other parts than necessary. There are problems that the unnecessary adhesive contaminates the surface of the substrate, peeling occurs due to insufficient adhesion between the adhesive and the substrate, and flexibility of the substrate deteriorates due to curing of the adhesive.

Therefore, an object of the present invention is to provide a light control sheet which is rich in flexibility, lightweight and excellent in handleability.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to a light control sheet in which an electrolyte solution or liquid crystal is sandwiched between a pair of electrode plates and contained, the electrode plates being thin film electrodes on a synthetic resin substrate. The present invention provides a light control sheet, which is an electrode film provided with a layer, and the electrode films are heat-sealed and sealed at their end portions to each other.

The electrode film used in the present invention refers to a film in which a thin film electrode layer (thin film electrode layer) is provided on a synthetic resin substrate film.

The substrate film used in the present invention is a transparent or translucent synthetic resin film, for example, polyester such as polyethylene terephthalate or polybutylene terephthalate; polycarbonate; polyamide such as nylon; polystyrene; polyolefin such as polypropylene or polyethylene. And a laminated film containing one or more of these. The thickness of the substrate film is preferably 10 to 30.
It is 0 μm.

The thin film electrode layer provided on the substrate film is a transparent electrode thin film, or a two-layer structure film composed of the transparent electrode thin film and the electrode thin film (oxidation / reduction electrode thin film). Normally, when utilizing the orientation of liquid crystals, only a transparent electrode thin film is used as a thin film electrode layer, and when using an electrolyte solution utilizing the electrochromy effect, a two-layer structure film is used as a thin film electrode layer. use.

First, as the transparent electrode thin film, SnO ₂ , S
Examples thereof include thin films such as n-doped In ₂ O ₃ and Al-doped ZnO. These thin films should be formed by a thin film forming method using a vacuum technique such as a vacuum vapor deposition method, a sputtering method, a CVD method, or a printing / coating technique such as a powder spray method, a spin coating method, a dip coating method, or a screen printing. You can The thickness of the transparent electrode thin film is preferably 5
It is 0 to 500 nm.

When the thin film electrode layer is a two-layer structure film composed of a transparent electrode thin film and an electrode thin film, the same transparent electrode thin film as described above can be used. Further, the electrode thin film contains an electrochromic substance. Examples of electrochromic substances include NiO, WO ₃ , and Mo.
Inorganic substances such as O ₃ , Cr ₂ O ₃ , In ₂ O ₃ and IrO and organic substances such as bursian blue and viologen derivatives can be used. These thin films are deposited, sputtered,
It can be formed by a thin film forming method using a vacuum technique such as a CVD method, or a printing / coating technique such as a powder spray method, a spin coating method, a dip coating method, or a screen printing. When a material that develops color by oxidation is used for one of the pair of electrodes, it is necessary to combine a material that develops color by reduction for the counter electrode. For example, if WO ₃ is used for one side, NiO is contained for the other side. The thickness of the electrode thin film is preferably 0.1 to 1 μm.

When the thin film electrode layer is a two-layer structure film, a transparent electrode thin film is first provided on the substrate, and then an electrode thin film is provided thereon. The transparent electrode thin film and the electrode thin film may be provided over the entire substrate or a part of the substrate.

The following may be used as the electrolyte solution or liquid crystal that is sandwiched between the electrode films and contained. First, as the electrolyte solution, LiClO ₄ , Na ₂
One or more inorganic salts such as SO ₄ and LiNO ₃ are combined with a protic solvent such as water or alcohol; an aprotic organic solvent such as ethylene carbonate, propylene carbonate, tetrahydrofuran or acetone; It is preferable to use one dissolved in two or more kinds. The concentration of the electrolyte solution is preferably 0.1 to 1
It is 0 mol / liter.

As the liquid crystal sandwiched between the electrode films and contained therein, nematic liquid crystal (for example, cyanobiphenyl type liquid crystal) or smectic liquid crystal (for example, bicyclohexane etc.) can be used. Other,
An aligning agent or the like for improving the degree of liquid crystal alignment can be used, and a spacer for inserting a certain amount of liquid crystal can be provided if necessary. The material of the spacer at this time is preferably the same material as the substrate,
For example, nylon or the like is used.

It is preferable that the above-mentioned electrolyte solution or liquid crystal is impregnated in the porous film so that liquid leakage is less likely to occur. As such a porous film, for example, a polyethylene resin film which is made porous by stretching when a solvent remains during production of a polyethylene resin can be preferably used. The porosity is preferably 30 to 95%, and the average through pore diameter is preferably 0.001 to 1 μm.

The light control sheet of the present invention comprises the above-mentioned electrolyte solution or liquid crystal sandwiched between a pair of electrode films and contained therein. At this time, the electrode film
The electrolyte solution or liquid crystal is sandwiched with the side on which the thin film electrode layer is provided facing inside. In the present invention, the ends of the pair of electrode films sandwiching the electrolyte solution or liquid crystal are sealed by heat fusion. At this time, the thin film electrode layer at the end of the electrode film to be fused may be peeled and removed.
In addition, a spacer resin may be sandwiched between the electrode films at the ends to be fused. The spacer resin may be made of the same material as the substrate film, but may have a different resin composition. Further, when the substrate film of the electrode film has a laminated structure, only the innermost (electrolyte solution or liquid crystal side) film or the outermost film may be heat-sealed. When only the outer film is heat-sealed, the end of the outer film to be welded is exposed from the other layers of the substrate film. As the heat fusion method, various methods such as heating with a heat knife, high frequency heating, ultrasonic heating and the like can be used.

The light control sheet thus obtained can be used by connecting both electrodes to, for example, a lead electrode and, if desired, further connected to a power source section via a switch. In the case of utilizing the electrochromy effect, it is possible to shield light by coloring the electrochromic substance by applying a voltage. The transmittance can be adjusted by changing the voltage application time. Once the voltage is applied and colored, the colored state is maintained even when the voltage is dropped by turning off the switch. Then, if a short circuit occurs, the color disappears. At this time, the light transmittance of the light control sheet is preferably 20 to 80%. In the case of a liquid crystal, the liquid crystal is oriented and colored by applying a voltage (or a voltage is cut off), and the color is erased by cutting a voltage (or a voltage is applied).

The light control sheet of the present invention can be used in a wide variety of fields such as light control windows, light control blinds, partitions, curtains, interior decorations and toys.

[0018]

Since the light control sheet of the present invention uses a resin film instead of glass, it is highly flexible, lightweight and excellent in handleability. Furthermore, unlike glass, it can be made into a very thin light control film. Further, since the films are bonded by heat fusion without using an adhesive, the manufacturing process can be simplified and the production efficiency can be significantly improved. Further, since no adhesive is used, it is possible to avoid various defects caused by the adhesive, such as inconvenience that the liquid electrochromic substance is deteriorated or deteriorated by the solvent of the adhesive, and the finished appearance is good. To be Also, because of the use of resin film,
It is also possible to make the seal structure finer, for example, to have a complicated multiple structure.

[0019]

The present invention will be described in more detail by the following examples. Example 1 A nylon film having a thickness of 50 μm was used as a substrate film, and an Sn ₂ -doped In ₂ O ₃ thin film (transparent electrode thin film, thickness 1500) was sputtered onto this substrate film.
Å), and a WO ₃ thin film (electrode thin film, thickness 6000 Å) was provided thereon by a sputtering method to obtain an electrode film. After providing the same transparent electrode thin film as the above on the same substrate as the counter electrode film, the NiO thin film (electrode thin film, thickness 500
0 angstrom) was used. As the electrolyte liquid to be put between these electrode films, LiCl
An O ₄ aqueous solution (concentration 1M) was used.

The above electrolyte solution was injected and sandwiched between the above electrode films (15 × 20 cm), and the end portions of the electrode films were heat-sealed with a heat knife and sealed. In addition, a lead electrode was provided at the end portion so as to be connected to the electrode film, and this was connected to a power source via a switch.

When the switch is turned on and a voltage is applied, each electrochromic substance reacts and colors in the pair of electrodes as follows, and when short-circuited, the reaction proceeds to the contrary and the color disappears.

NiO + H ₂ O − e ⁻ → NiOOH (coloring substance) + H ⁺ WO ₃ + xLi ⁺ + xe ⁻ → Li _x WO ₃ (coloring substance)

[0023]

According to the present invention, it is possible to provide a light control sheet which is highly flexible, lightweight and excellent in handleability. Therefore, the light control sheet of the present invention can be used in a wide range of fields and is industrially useful.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a light control sheet manufactured in Example 1.

[Explanation of symbols]

 1 Transparent electrode thin film 2 Electrode thin film 3 Electrolyte solution 4 Synthetic resin substrate film 5 Voltage application switch 6 Short circuit switch

Claims (1)

[Claims] 1. A light control sheet in which an electrolyte solution or liquid crystal is sandwiched between a pair of electrode plates and contained,
A light control sheet, wherein the electrode plate is an electrode film in which a thin film electrode layer is provided on a synthetic resin substrate, and the electrode films are heat-sealed and sealed at their ends.