JPH0452733Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention relates to a sealing structure for an electrochromic display using an electrochemical coloring substance, and particularly to a sealing structure for an electrochromic display body having a large substrate, a rectangular substrate, or a curved substrate. The present invention relates to a sealing structure suitable for electrochromic displays.

The electrochemical color forming substance used in the present invention is:
It is a substance that changes color when an electric field is applied, a phenomenon in which optical properties depend on electrical polarity, and is generally called an electrochromic (hereinafter referred to as EC) substance.

The EC display has Prussian blue on the transparent electrode.
A spacer is provided at the periphery between one electrode substrate coated with EC material such as tungsten oxide and the other electrode substrate, sealed with a sealing material, formed into cells, and propylene carbonate and perchloric acid are placed between the cells. It is injected with an electrolyte, typically a mixture with lithium.

[Prior art] In the sealing structure of an EC display, glass beads are used as spacers and sealed with epoxy adhesive (for example, Japanese Patent Laid-Open No. 56-22413), and sheet glass is cut into a prismatic shape. A spacer made of a spacer and sealed with an epoxy adhesive (for example, disclosed as prior art in Japanese Patent Application Laid-Open No. 56-22413),
Regarding the two-layer seal, an epoxy-based organic sealant is applied on the side facing the electrolyte, and an inorganic sealant such as glass paste is applied and welded on the side facing the outside world (Japanese Patent Laid-Open No. 56-24322). It is publicly known.

[Problems that the idea should solve]

The spacing between the substrates of an EC display is several tens of μm to several mm, and the size of the spacer is also selected accordingly. When conventional glass beads are used as spacing elements, many fine glass beads corresponding to the above-mentioned spacing are used, which is not easy to handle, and the glass beads scatter when assembling the display, making it difficult to install efficiently. . It is especially difficult to assemble large boards, rectangular boards with special shapes, and curved boards.
There is also a method of mixing glass beads in the sealant in advance, but if the bead diameter is several hundred μm or more, the glass beads may settle in the sealant application container and become unevenly distributed, or when applied to the substrate. It causes uneven discharge from the nozzle, and it is difficult to apply the glass beads evenly dispersed. In particular, during automatic application, the nozzle is considerably consumed, and sometimes the glass beads are damaged.

In addition, those using prismatic glass spacers,
The material, plate glass, must be precisely cut and polished, which requires labor and time and is inefficient. In addition, because of the lack of flexibility, contact with rectangular or curved substrates whose peripheral edges are arcuate is often insufficient.

Regarding sealing materials, in the case of conventional epoxy sealing materials, the amine compound used as a plasticizer reacts with the EC material, especially Prussian blue, and deteriorates it, and also has insufficient water resistance and weather resistance.
In particular, it loses its elasticity at low temperatures and becomes brittle, and its adhesive durability with glass substrates and conductive films is also insufficient.

When applying an inorganic sealant such as glass paste in addition to the epoxy sealant, when sealing is performed by heat welding the inorganic sealant, excessive heat may be applied to the substrate, epoxy sealant, as well as the EC material and electrolyte, causing deterioration. Alternatively, distortion occurs due to the expansion and contraction of these substrates, epoxy sealants, EC materials, etc., and this leads to deterioration.

[Means to solve the problem]

The present invention solves these problems. Namely, in an electrochromic display body in which an electrochemical color forming substance and an electrolyte are held between a pair of substrates and the periphery is sealed, the surface of the electrolyte is Butyl rubber is used as the sealing material on the side facing the outside (hereinafter referred to as the "inner sealing material"), polysulfide rubber is used as the sealing material on the side facing the outside (hereinafter referred to as the "outer sealing material"), and a spacer made of alkali-free glass rod is provided. The present invention provides an electrochromic display having a sealing structure consisting of:

The configuration of the present invention will be explained in detail using a specific example.

FIG. 1 is a side sectional view showing the basic structure of the EC display. Reference numeral 1 denotes a substrate on one pole side, which is usually transparent glass having a transparent electrode 2. Also,
The transparent electrode is patterned according to the content of the display and is formed to display numbers and the like. Further, an EC material 2 ¹ having the same shape as the display pattern of the transparent electrode, such as tungsten oxide, is thinned and deposited. 3
A substrate for forming the other electrode 4 is a glass substrate similar to 1, and an EC material 4 ¹ , such as a Prussian blue film, is deposited on the electrode 4.
Of course, the present invention is not limited to this example, and the substrate itself may be an electrode material. It may also be opaque, and can also be used as the background color of the display. Reference numeral 5 denotes a spacer for holding the display electrode and the counter electrode with an appropriate gap and for filling the electrolytic solution 7 therein, and is made of an alkali-free glass rod having a diameter of several 100 μm to several mm. Further, this spacer is inserted between two substrates, and its surroundings are molded and fixed with butyl rubber 6 as an inner seal material and polysulfide rubber 6 ¹ as an outer seal material.

Note that FIG. 2 shows a plan view of the sealing structure of an EC display using a rectangular circular substrate.

Alkali-free glass rod is produced by melting and clarifying an alkali-free glass composition batch such as E-glass, or by introducing a melted alkali-free glass cullet into a spinning tank and drawing it out from a spinning hole. By adjusting the spinning temperature, drawing speed, etc., a glass rod with a desired thickness and good dimensional accuracy can be produced. Note that "rod" refers to a columnar or elliptical columnar shape. Therefore, it can be produced more efficiently, in large quantities, and at a lower cost than the conventional method of producing prismatic glass by cutting it out of a plate glass and polishing the cut surfaces and edges. Furthermore, since it is flexible in all directions, it can be brought into contact with the surfaces of the rectangular circular substrate and the curved substrate illustrated in FIG.

In addition, unlike glass beads, they do not scatter during assembly, especially when assembling curved substrates, and are much easier to handle.

The requirements for an inner sealing material are that it has good adhesion to the substrate, especially glass substrates and conductive films, does not react with EC materials or electrolyte, does not leak electrolyte, and has the ability to block air (oxygen) and moisture. It has excellent performance, does not generate volatile gases, is highly durable and does not deteriorate during long-term use, and has good workability during assembly.
Butyl rubber is used as the elastic rubber material as it satisfies these requirements.

In the case of epoxy sealing materials, there are drawbacks such as reaction with EC materials, leakage of electrolyte over a short period of time, and deterioration over a short period of time.

The requirements for an outer sealing material include, of course, the excellent durability and workability mentioned above, but especially excellent adhesion to the substrate and its durability, high tensile strength, and appropriate elongation. Examples include being less affected by temperature fluctuations, rainwater, sunlight, etc. Polyurethane, silicone, etc. satisfy these requirements to some extent, but polysulfide rubber is used as a material that specifically satisfies these requirements. Therefore, during construction, there are no problems during heat welding that occur with conventional inorganic seals.

When using the above-mentioned two-layer seal structure, it can be left at room temperature24
No abnormalities were observed after 120 heat cycles (100°C to -40°C, 6 hours per cycle), but when conventional epoxy sealing material was used, the electrolyte did not change after being left at room temperature for 1 month and after 1 heat cycle. A leak had occurred. Furthermore, although seals made of a single layer of butyl rubber or a single layer of polysulfide rubber are superior to epoxy sealants, they are far inferior to two-layer seals.

To assemble and construct the EC display, a prismatic or cylindrical butyl rubber is placed near the periphery of one of the substrates prepared with the NESA film and EC film, and 1 piece of butyl rubber is placed on the inside of this, that is, on the side facing the electrolyte, for the entire periphery. Or a plurality of alkali-free glass rods are attached in contact with the butyl rubber. For example, FIG. 2 shows an example in which one glass slot is arranged around the entire periphery. Next, the other substrate coated with the film is placed opposite to the one substrate, and pressure is applied to bond and integrate them.

Furthermore, polysulfide rubber is injected from the outside of the butyl rubber, that is, the side facing the outside world, to the edge of the substrate using an injection gun, heated (40°C or less) and cured, and the electrolyte is injected through the injection hole prepared in advance. It is completed by doing. Note that the alkali-free glass rod may be placed outside the butyl rubber.

In the above-mentioned two-layer seal, if glass beads are scattered on the butyl rubber, there is a risk of air being trapped during crimping, or if glass beads are individually adhered to the outside of the butyl rubber and then filled with polysulfide rubber after crimping, it is a hassle. It requires a lot of work and is not efficient. On the other hand, when prismatic glass is arranged inside or outside of butyl rubber, air tends to remain on the contact surface of the prismatic glass with the substrate, especially when the substrate is curved like a rectangular or curved substrate. There is a strong tendency. Furthermore, significant curvature as shown in FIG. 2 is not possible. Note that a glass rod is highly flexible and can be bent freely since it is in line contact with the substrate, and there is no inconvenience such as air remaining.

[Effects of this invention]

As mentioned above, the present invention does not react with EC materials or electrolytes, and has excellent air and moisture barrier properties.
In addition to being a two-layer seal with various properties such as good adhesion to substrates and conductive films and no deterioration even after long-term use, it is also suitable for large substrates, rectangular substrates, and curved substrates, and can be assembled and constructed. It has a sealing structure with easy spacing, and its practical value is extremely high.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of an EC display body showing an embodiment of the present invention, and Fig. 2 is a plan view thereof. 1, 3... Substrate, 5... Alkali-free glass rod, 6... Butyl rubber, 6 ¹ ... Polysulfide rubber.

Claims (1)

[Scope of utility model registration request] In an electrochromic display that holds an electrochemical coloring substance and an electrolyte between a pair of substrates and seals the peripheral edge, butyl rubber is used as the sealing material on the side facing the electrolyte, and the sealing material on the side facing the outside world is used as the sealing material. An electrochromic display body characterized by a sealing structure in which polysulfide rubber is arranged as a filler layer and spacers made of non-alkali glass rods are provided.