JPH0365523B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to electrochromic displays.

(Prior Art) A conventional electrochromic display will be explained in detail using figures.

FIG. 2 is a cross-sectional view of an embodiment of a conventional electrochromic display and an explanatory view of the state in which it is used.

A conventional electrochromic display has a transparent electrode 2 in a pattern on one side of a transparent substrate 1, and an electrochromic layer 3 in a pattern forming a display area on the transparent electrode 2; There is an insulating layer 4 in the negative pattern, an electrolyte layer 5 on almost the entire surface, a reversible oxidation material layer 6 on almost the entire surface, a current collector layer 7 on the top, and a current collector layer 7 on the top. There is a protective layer 8 made of an insulator over the entire surface.

(Problems to be Solved by the Invention) The current collector layer of a conventional electrochromic display was a silver-based paste. However, in conventional electrochromic displays, repeated coloring and fading may cause precipitation of silver in the current collector layer on the display area and oxidation of the silver, resulting in accelerated deterioration.

(Means for solving the problem) An intermediate insulating layer with a negative pattern is provided as the display part on the reversible oxide layer, and the material of the current collector layer is a carbon-based conductive paste and the display on the carbon-based conductive paste. A paste containing a conductive filler having a lower resistance than the carbon-based conductive paste in the lead part and the negative pattern is used as the lead part.

(Function) Eliminates fatigue caused by repeated coloring and fading due to metal precipitation and oxidation, which occurs when coloring and fading occurs repeatedly, without reducing the coloring and fading responsiveness of the electrochromic display.

(Detailed Description of the Invention) An embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram of a cross section and usage state according to an embodiment of the present invention.

The electrochromic display of the present invention has a transparent electrode 2 on one side of a transparent substrate 1, an electrochromic layer 3 on the display area, an insulating layer 4 in a negative pattern with the display area, and an insulating layer 4 on almost the entire upper surface. An electrolyte layer 5 is provided, a reversible oxidation material layer 6 is provided on the upper part, an intermediate insulating layer 9 is provided on the non-display part of the upper part, a current collector layer 7 is provided on almost the entire upper part, and a lead is provided to the display part and the negative pattern on the upper part. The protective layer 8 is provided so as to cover the entire uppermost part 10.

A suitable material for the transparent substrate is a transparent solid material such as glass or plastic. Further, as the material for the transparent electrode, a thin layer of light-transmitting material such as indium oxide or tin oxide is suitable.

Regarding the materials of the electrolyte layer 5 and the insulating layer 4, first, the electrolyte layer is made of titanic acid, stannic acid, antimonic acid, antimonic acid, zirconium acid,
Examples include one or a mixture of two or more selected from niobic acid, tantalic acid, silicic acid, and the like. These materials are sometimes called hydrated metal oxides or metal oxide hydrates, and are often expressed by the general formula (MxOy.ZH ₂ O: x, y, and z are integers or fractions). Of course, just titanium oxide, tin oxide, antimony oxide,
It is different from oxides such as zirconium oxide, tantalum oxide, and niobium oxide mixed with water from the outside.

These above-mentioned materials are white powders that are effective in increasing the whiteness of the base, and they themselves exhibit high proton conductivity, with a resistance value of 1×10 ⁴ to 1×
The resistance is as low as 10 ⁵ Ω/cm, and when these are added, the coloring/decoloring response does not worsen, and on the contrary, both the response speed and the coloring density are improved. Also titanic acid,
Powders such as stannic acid, antimonic acid, zirconic acid, niobic acid, tantalic acid, etc., can be used even if small amounts of binders used in printing inks and coating compositions are added.
Its proton conductivity is maintained and it is effective as a solid electrolyte for electrochromic displays.

As a binder, the vapor pressure at 20℃ is 0.1
A polyhedral alcohol, a water-soluble polymer, or an aqueous emulsion type polymer, which is a liquid at mmHg or less, is preferable in order to maintain proton conductivity. In addition, as a solvent for forming an ink or a coating composition, water or a water-soluble solvent such as a lower alcohol or a lower ketone may be used.

Such a solid electrolyte has the advantage that it can be formed by printing, for example, screen printing or various coating methods, and can be applied to a wide range of thicknesses. For example, 2 to 2000μm can be used, especially 50 to 2000μm.
Preferred is a thickness of 400 μm.

Furthermore, any material that exhibits an electrochromic phenomenon other than tungsten oxide as shown in the following examples may be used as the material for the electrochromic body layer, such as transition metal oxides such as molybdenum oxide, titanium oxide, iridium oxide, etc. A mixture of these or an organic electrochromic material such as a viologen derivative fixed on an organic film may be used. The present invention includes these.

Next, regarding the insulator 4, a transparent insulating resin is basically used, and a coloring agent can also be added.

The basic component is preferably a cured resin that does not contain a solvent, such as an oxidative polymerization type resin, an ultraviolet curable resin, or a crosslinked polymerization type resin, and more preferably a resin that is suitable for printing and coating in an uncured state. The coloring agents that can be added to the insulation layer include those that affect insulation,
In other words, it is not preferable that the insulation properties deteriorate.
For example, carbon black, which is a good conductor, has poor insulation properties and cannot be used as a coloring material.

The coloring material used in the present invention is preferably a pigment with good insulation properties, and by using a screen printing ink containing such a pigment, an insulating layer showing good insulation properties can be obtained.

Note that the insulating layer can also be formed by a method other than printing and coating, such as vapor deposition or sputtering using an insulating inorganic or organic material.

The materials that make up the insulating layer include silicon dioxide (SiO ₂ ), magnesium fluoride (MgF ₂ ), cerium oxide (Ce ₂ O ₃ ), silicon nitride (Si ₃ N ₄ ), tantalum oxide (Ta ₂ O ₅ ), and oxide. Examples include yttrium (Y ₂ O ₃ ), silicon monoxide (SiO), and zinc sulfide (Zns).

The reversible oxidizing substances in the reversible oxidizing substance layer 6 include titanium dioxide, nickel oxide, cobalt oxide, iron oxide (FeO, Fe ₂ O ₃ or Fe ₃ O ₄ ), silicon dioxide, lead oxide, copper oxide (CuO), and iron sulfide. (FeS or _FeS2 )
Examples include metal oxides and sulfides such as bismuth oxide (Bi ₂ O ₃ ) and niobium sulfide, as well as hydroquinone derivatives and iron berlinate derivatives. In addition to the above-mentioned reversible oxidizing material, the reversible oxidizing material layer preferably contains carbon powder as a conductive filler for increasing electrical conductivity. Specifically, carbon blacks and carbon fibers such as buttress black, acetylene black, and conductive furnace black can be mentioned. These conductive fillers and powdered reversible oxidizing substances are combined with a suitable resin binder to form a reversible oxidizing substance layer, and resin binders include acrylic resin, vinyl chloride resin, epoxy resin, melamine resin, and guanamine resin. Resin binders used in common printing inks can be used, such as , alkyd resins, methacrylic resins, etc. By kneading these resin binder, conductive filler, and reversible oxidizing substance with a volatile solvent, an ink or coating composition for forming a reversible oxidizing substance layer is created. Considering that the volatile solvent mentioned here is applied by a printing method such as screen printing, the solvent is difficult to evaporate during printing, so the ink composition is less likely to change, and moreover, it can be applied quickly after printing. One that dries is preferable, has a boiling point of 150°C to 270°C, and is a true solvent for the resin binder. Specifically, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, tripropylene glycol monomethyl ether, diethylene glycol monobutyl ether, 2-phenoxyethanol, N-methylpyrrolidone, 2-pyrrolidone and the like can be mentioned. These solvents are completely removed from the reversible oxidizing material after coating and drying, except for a negligible trace amount remaining.

Furthermore, a trace amount of surfactant may be added to the above-mentioned ink for forming a reversible oxidizing substance to improve printability.

The material for the intermediate insulating layer may be a photocurable resin, a low-temperature thermosetting resin, an oxidatively polymerizable substance, etc., but the curing method is not particularly limited. Even if photocurable resin can be used for the intermediate insulating layer, it can be of radical polymerization type, radical addition type, cationic polymerization type,
Any cured resin such as acid-curable resin may be used. As the prepolymer, unsaturated polyester resins, urethane-modified resins thereof, unsaturated alkyd resins, acrylic resins, epoxy-modified resins thereof, and polyester-modified resins are excellent, but the present invention is not limited thereto.

The material of the current collector layer is preferably a low-resistance material;
Carbon-based conductive materials such as butt black, acetylene black, and conductive burner black are excellent because they do not cause metal deposition on the display area and do not cause fatigue due to repeated coloring and fading.

However, when a carbon-based conductive material or the like is used for the current collector layer, resistance becomes higher than when a metal-based conductive paste is used in areas other than the display area, resulting in poor coloring/decoloring responsiveness. In order to compensate for this, lead parts made of a conductive filler such as a low-resistance metal were provided in the lead parts of the non-display part and the negative pattern to prevent the deterioration of the color development and fading response.

The material for the lead part is a low-resistance conductive filler made of at least one of silver, palladium, nickel, copper, etc., a resin binder, and a volatile solvent mixed together to form an ink, which is coated and dried to form a good conductor. Possible examples include stacked layers.

Hereinafter, specific examples of usage of the present invention will be described.

Example 1 Transparent electrodes made of indium oxide and tin oxide were provided in a pattern on a glass substrate, and an electrochromic layer of about 4500 Å of tungsten oxide was provided on the display area on the transparent electrode by electron beam evaporation. Toyo Ink Mfg. Co., Ltd.'s product name SS-25000 is printed on the non-display area of the same layer by screen printing.
There is an insulating layer created by printing medium ink, and on the top, antimonic acid, glycerin, and water as a solid electrolyte are kneaded into an ink in a weight ratio of 5:1.1:0.6, applied by screen printing method, and dried. There is a film with a thickness of ~160 μm, and on top of that, a carbon-based conductive paste made by Fujikura Kasei Co., Ltd. under the trade name Dotite There is a layer of reversible oxidation material on almost the entire surface, and on top of that is a photocurable resin (product name: 7800-) manufactured by Matsushita Electric Works Co., Ltd.
There is an intermediate insulating layer formed by applying 56 on the display area and negative pattern using a screen printing method and hardening it, and a current collector using a screen printing method using a carbon-based conductive paste Dotite XC-71 manufactured by Fujikura Kasei Co., Ltd. The body layer covers almost the entire surface, and on top there is a lead part made of silver-based conductive paste, manufactured by Fujikura Kasei Co., Ltd. (trade name: XA-167), which is laminated on the display area and in a negative pattern using a screen printing method, and further on the top for protection. In Example 1, the entire surface was coated with the photocurable resin using a screen printing method to form a protective layer.

In Example 1, a bright blue color was obtained when a voltage of ±1.2 V was applied at a cycle of about 1 second, and no metal was deposited even after long-term operation.

Example 2 The counter electrode in Example 1 was made into an ink for forming a solid electrolyte by kneading antimonic acid, glycerin, and water at a weight ratio of 5:1.1:0.6, and then using a pigment (trade name: Cromarin) manufactured by DuPont in the United States. This was replaced with magenta ink created by adding 0.5% toner and layered using screen printing to create magenta pixels.

However, other configurations and materials are the same as in the first embodiment.

In the case of Example 2, when a voltage of ±1.2 V was applied at a cycle of 1 second, a mixed color of magenta and blue was developed and faded on the magenta base, and there was no metal precipitation even after long-term operation. Ta.

(Effects of the invention) Since the metal does not come into direct contact with the display, metal precipitation and metal oxidation are eliminated, and the life of the display is extended.
Moreover, the color responsiveness does not deteriorate.

[Brief explanation of drawings]

FIG. 1 is an explanatory view showing the cross section and usage state of one embodiment of the electrochromic display of the present invention. FIG. 2 is an explanatory diagram showing the cross section and usage state of one embodiment of a conventional electrochromic display. DESCRIPTION OF SYMBOLS 1... Transparent substrate, 2... Transparent electrode, 3... Electrochromic body layer, 4... Insulating layer, 5... Electrolyte layer, 6... Reversible oxidant layer, 7... Current collector layer, 8 ... Protective layer, 9 ... Intermediate insulating layer, 10 ...
Lead part.

Claims (1)

[Claims] 1. In an electrochromic display comprising at least an electrolyte layer and an electrochromic layer between a transparent electrode and a counter electrode comprising a reversible oxidant layer and a current collector layer on a transparent substrate, the reversible oxidizer layer An intermediate insulating layer is provided in a negative pattern with respect to the display part between the current collector layer and the current collector layer, and a carbon-based conductive layer is further provided as the current collector layer. An electrochromic display body characterized in that a negative pattern is provided with a low-resistance metal conductor material as a lead portion.