JPH0463889A - Phosphor and phosphor slurry - Google Patents

Abstract

PURPOSE:To obtain a phosphor providing a fluorescent membrane with excellent adhesive force and being useful for obtaining a highly precise tube by covering the surface of a phosphor particle with a specified compd. CONSTITUTION:The surface of a phosphor particle is covered with one or more (hydr)oxides and silicates selected from those of Mg, Cr, V and Zr.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a surface-treated phosphor and a phosphor slurry used in color cathode ray tubes, etc., and in particular to a phosphor slurry suitable for forming a phosphor film by a slurry coating method. It is something.

(Prior art) Generally, when forming a phosphor film on a cathode ray tube, a phosphor is dispersed in an aqueous solution containing polyvinyl alcohol (PVA), a chromate (such as ammonium dichromate), and a surfactant. Apply the synthetic resin slurry to the glass panel. Next, ultraviolet rays are irradiated through a shadow mask to cure the PVA in the irradiated areas, and then the fluorescent film in the uncured areas is removed by development to form a desired stripe or dot layer. This operation is repeated three times to form green, blue, and red fluorescent films. If a part of a predetermined pattern is missing or a particle layer falls off during the formation of this fluorescent film, the fluorescent film becomes a defective product. As described above, the adhesive strength of the fluorescent film is an extremely important issue in terms of performance and productivity. For this reason, many surface treatment methods have been studied in the past, in which silicon oxide, zinc hydroxide, etc. are attached to the surface of the phosphor to improve adhesive strength. (Tokuko Showa 61-
(Refer to Publication No. 46512) (Problem to be solved by the invention) However, with the recent development of high-definition tubes, there has been an increasing demand for smaller pattern diameters, and the quality required for fluorescent films has also become more sophisticated. The actual situation is that the adhesive force corresponding to this is not obtained.

The present invention aims to solve the above-mentioned problems and provide a phosphor and a phosphor slurry that have excellent adhesive strength and can efficiently form a high-definition pattern.

(Means for Solving the Problems) The present invention provides magnesium, chromium,
A phosphor characterized by adhering at least one of one or more oxides, hydroxides, and silicates selected from vanadium and zirconium, and containing the phosphor and polyvinyl alcohol in an aqueous solvent. This is a phosphor slurry characterized by the following.

Note that the amount of the above-mentioned deposits attached may increase the viscosity of the slurry if it is too large, so it is usually 5% or less based on the phosphor.
In particular, it is preferable to adjust the content to a range of 0.01 to 1%.

The phosphor of the present invention can be applied to phosphors normally used in color cathode ray tubes, such as zinc sulfide-based phosphors, europium-activated yttrium oxide phosphors, europium-activated yttrium oxysulfide phosphors, and the like.

(Function) In the present invention, the coated surface of the phosphor slurry containing the above deposits is irradiated with ultraviolet rays to crosslink and insolubilize the resin, thereby curing the coating film. 2. If the deposit is attached, this deposit acts like a crosslinking agent, hardens the PVA in the vicinity of the phosphor particles, and forms a stronger coating film. Although the insolubilization reaction of this type of crosslinking agent is generally complicated, it is thought that it forms a complex salt with PVA.

As described above, in the present invention, by blending a specific adhesion material, the phosphor can be reliably and firmly adhered,
The edges of the pattern can also be finished neatly.

In order to evaluate the adhesive strength, the thickness of the fluorescent film is kept constant, the exposure amount is varied, the pattern is carved out, and the minimum pattern diameter is measured. That is, the turn diameter (at the minimum exposure amount that can form a pattern) is called the adhesive force, and the smaller this value is, the stronger the adhesive force is evaluated as shown in FIG.

Examples of the present invention will be described below.

(Example 1) 120 g of blue-emitting phosphor (referred to as phosphor A) and 1 part pure water
80 g was added thereto, and 7.4 ml of a 20% aqueous magnesium sulfate solution was added while stirring. This aqueous solution was adjusted to pH 11 with a 4% NaOH aqueous solution. After standing for a certain period of time, the supernatant liquid was removed by decantation, the residue was filtered, and then dried at 120°C for 14 hours and passed through a 500 mesh sieve to attach magnesium hydroxide to the surface. . When the amount of magnesium attached to this phosphor (referred to as phosphor B) was analyzed, it was found to be 0.1%. Using this phosphor B, a phosphor film was formed on a cathode ray tube, and the adhesive strength was evaluated, and the results are shown in Table 1.

(Example 2) 180 g of pure water was added to 20 g of the blue-emitting phosphor Al used in Example 1, 1.6 g of 10% sodium dichromate was added while stirring, and the PFI was adjusted to 2 with 10% hydrochloric acid.

Next, it was reduced with 1N sodium thiosulfate, and the pH was adjusted to 7 with 10% aqueous ammonia. After being left for a certain period of time, the clear liquid was removed by decantation, the residue was filtered, and then dried at 120°C for 14 hours and passed through a 500 mesh sieve to adhere chromium hydroxide to the surface. I let it happen.

When the amount of chromium deposited on this phosphor (referred to as phosphor C) was analyzed, it was found to be 0.04%.

Using this phosphor C, a phosphor film was formed on a cathode ray tube, and the adhesive strength was evaluated, and the results are shown in Table 1.

Note that similar results were obtained for the phosphor obtained by drying the phosphor of the above example at 320° C. and having chromium oxide adhered to the surface.

(Comparative Example) Adhesive strength was evaluated using the phosphor A that does not adhere to any deposits in Example 1. Table 1 shows the results.

*) Film weight per 1 cm' of phosphor film As is clear from Table 1, the adhesive strength of the phosphor films of Examples 1 and 2 in which the specific adhesion of the present invention was attached to the phosphor surface was that of the comparative example in which no adhesion occurred. Approximately 20μ compared to the adhesive strength of fluorescent film
It can be seen that m has been improved.

Note that chromate is added to the phosphor slurry applied to cathode ray tubes, including comparative examples, but comparing Example 2, in which chromium compounds were attached to the phosphor surface, and Comparative Example, in which no chromium compounds were attached. As is clear, the chromate added to the phosphor slurry does not function as a deposit as intended in the present invention.

(Effects of the Invention) By adopting the above configuration, the present invention can increase the adhesive force and efficiently form a finer pattern, which can greatly contribute to the production of high-definition tubes. It is something that contributes.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between exposure amount and pattern diameter. relative exposure

Claims (2)

[Claims] (1) One or more oxides selected from magnesium, chromium, vanadium, and zirconium on the surface of the phosphor particles,
A phosphor comprising at least one of hydroxide and silicate attached thereto. (2) A phosphor slurry comprising the phosphor according to claim 1 and polyvinyl alcohol in an aqueous solvent.