JPS58208380A - Paste to form thin fluophor film - Google Patents

Abstract

PURPOSE:To provide a paste for formation of thin film of fluophor which comprises (a) thickener, (b) organometallic compd. consisting of a metal atom constituting fluophor matrix and an organic substance, (c) activator for fluophor and (d) solvent and is capable of readily forming a large area of fluorescent surface at low cost with a high productivity. CONSTITUTION:The paste comprises (a) thickener, (b) organometallic compd. consisting of a metal atom constituting fluophor matrix and an organic substance, (c) activator for fluophor consisting of the organometallic compd. and (d) solvent which dissoives (a), (b) and (c). The organometallic compds. are those which do not decompose under normal conditions of use but decompose at a temperature below the combustion temperature of the organic thickner and it is necessary to select good solvents for them. Among zinc-based organometallic compds., for example, zinc bisacetylacetonate is preferred because of its chemical stability. Preferred organic thickener is ceiluiosic compd. such as nitrocellulose and ethylcellulose.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a phosphor thin olfactory forming paste in which a phosphor thin film is formed by screen printing or the like.

In recent years, methods for producing phosphor thin films have been extensively studied, as seen in electroluminescent devices (Fi L). To date, many methods have been tried to produce thin films, such as vacuum evaporation, sputtering, and ion blating, and some have been put into practical use. Using these methods, good thin films can be obtained, but the substrate must be placed under high vacuum, making it difficult to mass-produce.
Furthermore, it is difficult and expensive to obtain a fluorescent surface with a large area.

In contrast, the present invention provides a phosphor thin film forming paste that can easily form a phosphor thin film by screen printing, etc., and is inexpensive, easy to mass-produce, and easily forms a large area of phosphor surface. can be formed into

Hereinafter, the present invention will be explained regarding a zinc sulfide phosphor.

First, we will explain the production of the paste used for thin kansei sound.

The organometallic compound consisting of metal atoms and organic matter that constitutes the phosphor matrix is one that does not decompose under normal usage conditions, but decomposes below the combustion temperature of the organic thickener described below, and has good properties. It is necessary that a suitable solvent be found.

For example, as the organometallic compound of quick lead, zinc suacetylacetonate is suitable because it is chemically stable.

A solvent for an organometallic compound is required to have a high Buddha point and appropriate viscosity to be suitable for screen printing and the like. For example, the solvent for the zinc bisacetylacetonate may be terpineol, 2-ethylhexanol, benzylalol, etc. 17) lX4!alcohol, benzyl acetate, high boiling point esters such as dimethyl heptalate, calpitol, butyl calpitol. , high boiling point alfurs such as butyl cellosolve, etc. are used.

The organic thickener is required to be a common solvent with the organometallic compound, and cellulose compounds such as nitrocellulose and ethylcellulose are often used. An organic thickener made of a cellulose compound is dissolved in a mixture of one or more of the above organic solvents to give a binary viscosity, and an organic metal made of one or more phosphor host metals is added to the solution. By dissolving the compound and stirring and mixing thoroughly, a paste for forming a phosphor matrix thin film can be obtained. The paste thus prepared is applied onto a substrate such as glass using a doctor knife, a roll tool, screen printing, or the like, and then dried. At this time, in order to improve adhesion between the dry film and the substrate, it is necessary to sufficiently degrease and clean the surface of the substrate.

The drying temperature varies depending on the type of solvent used, the stability of the organic metal, etc., but is generally around 100°C. When a dried substrate is heated in a gas atmosphere consisting of a compound of negative atoms constituting the phosphor matrix above the temperature at which the coated organometallic compound thermally decomposes, the metal atoms are liberated and at the same time the negative atoms in the atmosphere are A phosphor host compound is formed on the substrate. For example, in the case of a zinc sulfide phosphor, when heated to the decomposition temperature of zinc bisacetylacetonate, 130°C or higher, in an atmosphere of hydrogen sulfide or carbon disulfide, the zinc is liberated and immediately combines with sulfur atoms in the atmosphere. Reacts to form zinc sulfide.

When the substrate on which this phosphor matrix compound is formed is heated at the combustion temperature of the organic thickener in air or oxygen-added air, the thickener burns out and the phosphor remains on the substrate. A matrix thin film is formed. For example, when nitrocellulose is used as a thickener, the thickener is completely burned when heated to 300 to 500° C. in air, resulting in a phosphor matrix thin film.

The thin film thus prepared has excellent adhesion to the substrate, and can be made transparent by appropriately selecting the coating thickness and burning conditions for the thickener. In addition, the film thickness can be adjusted to 50% by adjusting the amount of organometallic compound contained in the paste and the coating film thickness.
It can be easily varied over a wide range from 0 to 3000 angstroms. However, if the film thickness is greater than the above, minute racks will occur in the film, making it difficult to obtain a good product.

The phosphor matrix thin film thus formed preferably contains a phosphor activator. One method for adding an activator is to add the phosphor matrix thin film forming paste to the phosphor matrix thin film forming paste.
A phosphor activator (for example, an organometallic compound consisting of silver, copper, aluminum, etc.) and an organic substance is added in advance in the required amount, and the phosphor activator is manufactured in the same order as the method for manufacturing the phosphor matrix thin film described above. For example, a phosphor thin film loaded with a desired activator can be formed. However, in this case, the organometallic compound consisting of the phosphor host metal and the organometallic compound consisting of the activator metal may have different thermal decomposition wettability, so in that case, the one with the lowest decomposition temperature should be You can process it sequentially.

Examples of the present invention will be described below. The copper-activated lead sulfide phosphor thin film is formed by the following method.

Example bisacetylacetonate zinc, butyl carbitol:butyl cellosolp:pendylacetate)-3:2:5
The paste is dissolved in a mixed organic solvent mixed at a ratio of 15% by weight and 1s of nitrocellulose as a thickener to make the paste viscosity so, soooo centiboise. At this time, the content of zinc bisacetylacetonate is adjusted to 1 to 20% by weight based on the total amount of the paste.

Copper acetylacetonate was added to this paste as an activator, and copper or
Add 90% of the ingredients and stir to mix.

Using this paste, screen print on a glass substrate with a screen plate of 250 mesh stainless steel net,
Dry at 110°C for 30 minutes. The dried substrate is placed in a furnace, and the atmosphere is sufficiently replaced with an inert gas, and further replaced with hydrogen sulfide gas, and then the temperature is raised to 130 to 160°C. At this time, bisacetylacetonate-1tE lead decomposes and zinc sulfide is produced.

After the reaction is completed, the atmosphere is changed to an inert atmosphere again and the temperature is raised to 200 to 250°C. Copper acetylacetonate decomposes and copper is liberated and diffuses into the previously formed zinc sulfide. After the copper decomposition reaction is completed, the atmosphere is replaced with air and heated to 500°C.
When baked for 30 minutes, the thickener is completely burned out, and a transparent copper-activated lead sulfide phosphor thin film is formed on the glass substrate.

As described above, by using the paste of the present invention, a phosphor thin film can be easily and inexpensively produced.

Agent: Patent Attorney Takeshi Kenjibe

Claims (1)

[Scope of Claims] (1) A thickener, an organometallic compound consisting of a metal atom and an organic substance constituting a phosphor matrix, a phosphor activator consisting of four organic gold compounds, and the thickener. 1. A paste for forming a phosphor thin film, comprising a solvent for dissolving an organometallic compound and a phosphor activator. (2) A phosphor according to claim (1), wherein the organometallic compound comprising a metal atom and an organic substance constituting the phosphor matrix is zinc bisacetylacetonate. Paste for forming thin films. (3) A phosphorescent thinning paste according to Claim No. 11, characterized in that the thickener is a cellulose compound. (2) A paste for forming a phosphor thin film, characterized in that the phosphor activator is copper acetylacetonate. (5) A paste for forming a phosphor thin film as described in claim (1). 1. A paste for forming a phosphor thin film, wherein an organometallic compound composed of metal atoms and an organic substance constituting the phosphor matrix decomposes at a temperature below the firing temperature of the thickener.