JPH0356458B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of manufacturing an electrochromic display element. Generally, the basic structure of an electrochromic display element is as shown in Figure 1.
A substrate 2 provided with two electrodes 1 is sealed with a sealing material 3, and after a liquid substance 4 containing a displayable substance is injected through an injection port, the injection port is sealed with a sealing material 5. It consists of: Here, as the electrode 1, a transparent electrode formed by forming a film of indium oxide or tin oxide on the glass substrate 2 by vapor deposition or the like is used. Before the electrode material is deposited on the surface of the substrate 2 used in the liquid crystal display element, an SiO ₂ film is formed to prevent contamination of the liquid crystal by metal ions contained in trace amounts in the glass component. When guaranteeing the quality of display elements,
Important characteristics include sealing characteristics and repeated operation life characteristics. That is, since a liquid substance is injected into the inside of the element, if the sealing strength is weak or unstable, the liquid may leak to the outside. In particular, electrochromic display elements have a lower boiling point than liquid crystals.
This sealing property is particularly important since organic solvents with high vapor pressure and high solubility are used. One of the two opposing electrodes 1 is a display electrode,
When the other electrode is used as a counter electrode, the display electrode forms the patterned electrode desired to be displayed. There are two ways to form a pattern: one is to form the pattern from the beginning during vapor deposition, and the other is to etch electrodes other than the display electrodes using a photo-etching method after forming the vapor-deposited film, or to form an insulating film. be. For example, suppose that a circular display pattern as shown in FIG. 2 is formed by etching.
As a result, the electrode 1 is attached to a part of the surface of the glass substrate 2. Therefore, when sealing the display electrode and the counter electrode, the sealing material must adhere to the glass surface and electrode surface of the display electrode. Commonly used sealants include epoxy resin and low melting point glass. When an epoxy resin is used as a sealing material, the adhesion of the epoxy resin between the glass 2 and the electrode 1 such as indium oxide or tin oxide is different. Therefore, one of the reliability tests for display elements is in a high temperature and high humidity atmosphere (+70℃, 95R.H.
%), a difference can be seen when an abandoned test is performed. That is, the adhesion to the electrode surface is worse, although it depends on the degree of cleaning on the surface. Epoxy resins generally consist mainly of a resin having an epoxy group and a curing agent, but various additives are also mixed in to improve printability. The method of use is to print using a screen printing method or the like, and then harden the resin by heat treatment. However, unlike liquid crystal display elements, electrochromic display elements use organic solvents with good solubility, so the solvent easily penetrates into the cured epoxy resin, eluting low-molecular components, etc., and entering the element. spread,
This will repeatedly reduce the lifespan. Furthermore, when epoxy resin is in contact with an electrode, there are many chemically reactive and electrochemically active substances in the resin, so when a voltage is applied, more resin The components inside will easily elute and diffuse, which will repeatedly reduce the lifespan. On the other hand, when a low-melting glass powder is used as the sealing material, there is no component that dissolves in an organic solvent, so there is no internal contamination caused by the sealing material. When left in a high-temperature, high-humidity atmosphere, sealing failure due to moisture penetration, which occurs when sealing with epoxy resin, will occur.
This is not observed at all when low melting point glass powder is used. However, the method of using low melting point glass as a sealing material involves screen printing a paste consisting of an organic solvent and a binder such as acrylate resin on one or both substrates, followed by evaporation and thermal decomposition of the solvent and binder. After that, both substrates are placed facing each other and fired for sealing. During this sealing, several g/cm ² to 100
Apply a weight of about g/cm ² . Therefore, if the sealing material is applied directly onto the In ₂ O ₃ or SnO ₂ transparent electrode, the glass sealing material will sink into the electrode, causing the electrode to break or reducing the electrical resistance. This may lead to the phenomenon of increasing As described above, in conventional sealing methods, the adhesiveness of the sealing material between the substrate surface and the electrode surface is poor, resulting in deterioration of the sealing properties, and the elution of the sealing material repeatedly deteriorates the service life. In addition, the pressure applied during sealing could cause the electrodes to break or the resistance to increase. The present invention was made in view of these problems, and involves applying a silicon compound that is soluble in alcohol, water, or a mixed solution thereof to the sealing portion on the electrode surface or the substrate surface, and applying the silicon compound to the sealing portion on the electrode surface or the substrate surface. By performing heat treatment to form a stable thin film and then sealing it, we can manufacture electrochromic display elements with good sealing properties, no deterioration of repeated life, no electrode disconnection, and no increase in resistance. The present invention provides a method. An embodiment of the present invention will be described below with reference to the drawings. FIG. 3 is a diagram for explaining one embodiment of the present invention, in which an electrode 1 is formed on a substrate 2 in a circular pattern by an etching method, and then a silicon compound 6 dissolved in alcohol or water at room temperature is etched. is applied to the sealed portion of the substrate 2 and the non-displayed portion of the electrode 1, and after high temperature treatment, the sealing is performed. By going through such a process, the adhesion will be improved and the variation in adhesive strength will be reduced. Generally, the basic structure of this silicon compound film is
It is _SiO2 . The characteristics of this silicon compound are that it is easy to obtain a thin film (500~2000〓) with a uniform surface, and because the solubility varies depending on the heat treatment temperature, it can be easily etched into a third layer using a photoetching method.
It is possible to create a pattern like the one shown in the figure. Also,
A counter electrode treated with a similar silicon compound has better adhesion. Therefore, the sealing characteristics as an element are also improved. In this way, by applying a silicon compound to the sealing parts on the substrate and electrodes and performing the sealing process after heat treatment, this silicon compound film firmly adheres to the substrate and electrodes, and also seals. It also has good adhesion to the material, so there is no deterioration in the sealing properties of the element, and the elution of the sealing material into the inside of the element is reduced, improving the repeat life. Furthermore, when applying pressure during sealing, This film prevents the sealing material from penetrating into the electrode, thereby preventing disconnection of the electrode and increase in resistance. By the way, so far we have mainly talked about the sealing material and the sealing parts on the electrode surface and the substrate surface, but the thin film of the silicon compound of the present invention can also be used as a masking material for other than electrodes to be displayed. . In other words, even if an electrode pattern is created using the photoetching method, it is necessary to mask the part of the electrode that leads to the outside of the element, but as mentioned above, silicon compounds are thin films and have good insulation, chemical stability, Because it has excellent adhesion to the base, it has excellent properties as a masking material. Furthermore, since the masking pattern can be created at the same time as the pattern for the sealed portion is produced, the material cost and man-hours for manufacturing can be reduced regardless of whether only the pattern for the sealed portion is produced. Since a film with a thickness of 1000 mm or less can be used, the presence of the masking material is almost invisible to the human eye, resulting in a clear display pattern. Note that there is no problem even if the silicon compound of the present invention contains phosphorus, arsenic, etc. within a range that does not affect the insulation properties or the degree of contamination. Specific examples of the present invention will be described below. Example 1 The electrochromic material used in the experiment was a styryl dye. The electrolytic solution consists of a supporting electrolyte and a non-aqueous organic solvent. As a supporting electrolyte, tetrabutylammonium perchlorate,
Propylene carbonate, dimethylformamide, acetonitrile, etc. were used as the solvent. As the epoxy resin, one-component products manufactured by EHC and Shikoku Kasei were used. The sealing property test was conducted under the following atmosphere. 1 High temperature storage +80℃ 2 Low temperature storage -30℃ 3 Heat cycle 1 cycle is +80℃ for 30
4, 30 minutes at -30°C, high temperature and high humidity, +70°C, humidity 90-95%, repeated operation.The life characteristics were determined by repeatedly applying a DC voltage of 1.2V in the positive and negative directions to cause the phenomenon of fading and color development. As the silicon compound, one manufactured by Tokyo Ohka was used. (Product name: OCDSi-1000) A film was formed by photoetching on the areas where the sealing material of the display electrode and the counter electrode was applied (the area shown in FIG. 3, 6). The heat treatment temperature is
The temperature was 500°C for 30 minutes. The film thickness is 1300 mm. Table 1 shows the results of the examples.

[Table] Example 2 The electrochromic substance used in the experiment was a styryl dye. The electrolyte includes a supporting electrolyte and a non-aqueous organic solvent. As a supporting electrolyte,
Tetrabutylammonium perchlorate was used, and propylene carbonate, dimethylformamide, acetonitrile, etc. were used as the solvent. As the epoxy resin, one-component products manufactured by EHC and Shikoku Kasei were used. As the low melting point powder glass, one manufactured by Nippon Electric Glass Co., Ltd. was used. The substrate used was one in which a thin film of a silicon compound was formed on the sealing portion. As the silicon compound, one manufactured by Tokyo Ohka was used.
(Product name: OCD P-Si-film P-59310). The parts to be sealed were coated with high precision using a photoetching method. The heat treatment temperature was 500°C for 30 minutes. The film thickness is 1300 mm. The distance between opposing electrodes is 30±3 μm. The sealing properties and display properties of the sealing material were examined under the above conditions. 1 High temperature storage +80℃ 2 Low temperature storage -30℃ 3 Heat cycle 1 cycle is +80℃ for 30
minutes, 30 minutes at -30℃ 4. Leaving at high temperature and high humidity +70℃, humidity 90-95% 5. Repeated operation life for fading and developing color DC voltage 1.2V
Table 2 shows the results of the examples.

[Table] As described above, in the method of manufacturing an electrochromic display element, the present invention involves applying silicon compounds to the surfaces of the substrates and electrodes to be sealed, before facing and sealing the substrates forming the electrodes. After forming a stable thin film, sealing is performed. When epoxy resin or low melting point glass is used as the sealing material, the sealing performance and the manufacturing yield of the device are improved. In addition, this silicon compound simultaneously
Since it has good properties as a masking material for display electrodes, it can also be used to mask electrodes at the same time.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing the basic structure of a display element, Figure 2 is a plan view showing an example of a display electrode, and Figure 3 is a cross-sectional view showing the basic structure of a display element.
The figure is a plan view showing one step of the method of the invention. DESCRIPTION OF SYMBOLS 1... Electrode, 2... Glass substrate, 3... Sealing material, 4... Displayable substance, 5... Sealing material, 6...
...A thin film of silicon compounds.

Claims (1)

[Claims] 1. A method comprising the step of: placing two substrates on which electrodes are formed facing each other with a display material interposed therebetween, and sealing the peripheral portions of the substrates; 1. A method of manufacturing an electrochromic display element, which comprises applying a silicon compound to a portion to be coated with a sealing agent, then heat-treating the area, and then sealing the two substrates. 2. The method for manufacturing an electrochromic display element according to claim 1, wherein the silicon compound is dissolved in alcohol, water, or a mixed solution thereof. 3. The method for manufacturing an electrochromic display element according to claim 1, wherein the sealing material is made of powdered glass with a low melting point. 4. The method of manufacturing an electrochromic display element according to claim 1, wherein the sealing material is made of epoxy resin.