JPS62161881A - Surface-treated fluorescent substance - Google Patents

Abstract

PURPOSE:To obtain the titled fluorescent substance small in the interference in other color's stripes and dots when color picture tube is used, thus favorable for the fluorescent surfaces of other cathode ray tubes, by attaching the surface of fluorescent substance particles with titania particles with the average size of the primary particles falling below a specified level. CONSTITUTION:The objective fluorescent substance can be obtained by attaching (A) the surface of fluorescent substance particles with (B) pref. 0.001-1.0wt% based on the component A, of titania particles with the average size of the primary particles <=500 (pref. 20-300)mmu pref. using a titania sol. EFFECT:Outstanding in uniformity and minuteness of stripes and dots.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is characterized in that the average particle diameter of primary particles on the surface of the phosphor particles is 500.
This invention relates to a surface-treated phosphor to which titania particles of millimicrons or less are attached. More specifically, the present invention relates to a surface-treated phosphor suitable for use in the fluorescent surface of color picture tubes and cathode ray tubes.

[Conventional technology]

Generally, phosphors are used in color picture tubes by coating each color in the form of stripes or dots on a face plate as a phosphor film.

In order to increase the contact force with the glass surface, prevent color mixing (cross contamination) on the phosphor film, and obtain uniform and dense stripes and dots, the phosphor is coated with:
Various surface treatments have been applied. However, silicate compounds, phosphate compounds, oxides of various metals, and the like are known as substances for such surface treatment. Among them, 5
iO7 is effective for surface modification of powders containing phosphors;
! It is known that the sol of 'fLSIQ2 can be effectively used as a surface treatment agent.

However, with the demand for improved performance such as higher definition of color picture tubes, the coating characteristics required for phosphors are becoming stricter day by day, and the current situation is that conventionally known surface treatment technologies are no longer able to meet these demands. It is.

[Problem that the invention seeks to solve]

(The purpose of the present invention is to have sufficient adhesion to the glass surface, eliminate cross-contamination (color mixing) between phosphors with different emission colors, and achieve uniformity and density of the coating film. The object of the present invention is to provide a surface-treated phosphor having characteristics that can be used.

Therefore, in order to achieve the above object, the present inventors have repeatedly searched and studied various surface treatment materials and treatment methods, and have found that the phosphor whose surface is treated with titania particles is significantly superior to conventionally known phosphors. The present invention has been completed based on the discovery that the above object can be achieved.

[Means for solving problems]

That is, the present invention relates to a surface-treated phosphor in which titania particles having an average primary particle diameter of 500 millimicrons or less are adhered to the surface of the phosphor particles.

The present invention will be explained in detail below.

The surface-treated phosphor of the present invention is manufactured, for example, as follows.

After dispersing the phosphor particles in approximately 2 to 5 liters of deionized water, titania particles or titania sol dispersed in a solvent (e.g., water, alcohol, etc.) are added, and then the p of the dispersion is
By controlling ① to 3 to 9, titania is adsorbed onto the surface of the phosphor.

This is filtered, washed with water, etc., then dried and smoked at 80°C to 250°C, and then passed through a sieve of 300 mesh or more to be dispersed and finished.

In addition, at the same time as attaching titania particles to the phosphor particles,
Other surface treatments may be performed, such as uniform deposition of 5102 sol, deposition of zinc hydroxide compounds, etc., or these additional treatments may be performed in separate steps before or after the titania surface treatment step.

As for the "titania particles" used here, commercially available products can be used as they are without any problems, and examples of commercially available products include titanium oxide P-25 made by Nissan Kagaku Wa Co., Ltd., Tikunzol Oxide, and Nippon Aerosil Co., Ltd.

The amount of M attached to the phosphor particles of titania particles is preferably 0.001 to 1.0% by weight, more preferably 0.002 to 0.1% by weight based on the weight of the phosphor. It is. This is because by setting the amount within this range, a sufficiently satisfactory color mixing prevention effect and membrane filling performance can be obtained.

Further, in the present invention, the titania particles attached to the phosphor particles have an average primary particle diameter of 500 millimicrons or less. By setting the average particle size to 500 millimicrons or less, adhesion to the phosphor particles is ensured, and the formation of aggregates of titania particles on the phosphor particles can be prevented. More preferably, the average particle size of the primary particles of titania particles is 20 to 300 millimicrons. Compared to the case where a titania sol of 20 millimicrons or less is used, a film-like titania particle layer is formed on the phosphor.
This is because it is possible to increase the surface area of titania particles at ~300 millimicrons. The average particle diameter of the primary particles referred to herein was determined as follows.

0.2wt% of 100cc in a 200cc glass beaker
Sodium hexametaphosphate is added, and titania sol or titania powder is added to the mixture in an amount of 0.1 wt% to 0.01 wt% of titania. While stirring with a stirrer, use an immersion type ultrasonic crusher (Kaiyo Denki TA-42).
80 type) for 3 minutes at 30W, and then the solution was poured into a centrifugal sedimentation method particle size analyzer 5A-CP3 (manufactured by Shimadzu Corporation).
MEDrAN D obtained by measuring the particle size with this device.
f8 was defined as the average particle size.

Also, the "phosphor particles" that can be used herein include all those that can be used in color cathode ray tubes. Examples include zinc sulfide-based, rare earth-activated oxide-based, and rare-earth activated oxysulfide-based phosphors; more specifically, ZnS:Δg
, ZnS:Cu, ZnS:Δu, ZnS:Cu.

Δu, Zn5iO<:! , In, Xn1(PO
<)2:! Jn, Y2O3: [iu.

YzLS:[Eu, YVO-:[iu, etc. can be mentioned.

Incidentally, in the surface-treated phosphor of the invention, phosphor particles to which a pigment is further attached can also be used for the purpose of improving the contrast of the phosphor film.

The phosphor of the present invention surface-treated by the above method has PV
A. A color method consisting of dispersing dichromate in a slurry consisting of water and a surfactant, spinning it onto a cathode ray tube panel, and then creating a stripe or dot pattern using a light printing method through a shadow mask. It can be used in the manufacture of cathode ray tubes.

When the surface-treated phosphor of the present invention is used for color cathode rays, there is little contamination with other color stripes or dots or contamination from other colors, and the stripes and dots are excellent in uniformity and density, making the cathode ray tube better as a whole. This has the effect of not only improving the quality of the phosphor film compared to the conventional method, but also improving the yield in the process of manufacturing the phosphor film of cathode ray tubes. This effect is particularly remarkable when phosphor particles to which pigments with gelatin as a binder are attached are used as the raw material.

Example 1 By the conventionally known method shown in Japanese Patent Application Laid-Open No. 53-5088,
A blue-emitting silver-activated zinc sulfide phosphor with cobalt blue pigment was prepared using gelatin and gum arabic as adhesives. This had 0.4% by weight of gelatin, 0.4% by weight of gum arabic, and 1.5% by weight of cobalt blue adhered to the phosphor, and was dried and crushed. Disperse 1,000 g of this pigmented phosphor in 21 pure water, stir well and add titania sol (Titanium oxide sol, Nikichi Kagaku, Ltd.) with an average particle size of 70 mm to 0.1 weight ffi of titania.
%. Add this with dilute acetic acid to pl+4.0
After lowering the temperature to 100.degree. C., it was filtered, dried at 100.degree. C., passed through a 400-mesh filter, and ground to obtain the surface-treated phosphor of the present invention.

The phosphor thus obtained was applied by the following method.B
- G color mixing and film filling properties were evaluated and the results are shown in Table 1.
Shown below.

[Application method]

The coating was carried out in the same manner as the slurry method for manufacturing color cathode ray tubes, as follows. The phosphor is dispersed in a coating solution mainly consisting of water, polyvinyl alcohol, dichromate, and a surfactant. A commonly used green phosphor is first applied by spin coating to a color cathode ray tube panel that has been subjected to a black matrix or pre-coating process and then dried. This is irradiated with ultraviolet light through a blind mask, then washed with warm water and dried to obtain a green phosphor dot pattern at a predetermined position.

Next, in the same manner as on the panel on which the green phosphor pattern was formed, a pattern of the blue phosphor of the present invention is formed at a predetermined position of the color cathode ray tube. A conventional conventional red phosphor pattern is then created in place.

[B-c color mixing test]

One dot (diameter 180 millimicrons) is made of blue phosphor mixed on a green phosphor dot while emitting light with ultraviolet rays.
B-G color mixture was determined by measuring the number of blue phosphors on the top.

[Membrane sufficiency]

The film filling properties were evaluated by applying a phosphor over the entire surface of a cathode ray tube panel glass, observing the dried product under a microscope using transmitted light, and comparing it with stacked samples using a sensitive evaluation on a 5-point scale.

Examples 2 to 5 The amount of titania sol used in Example 1 was 0.1% by weight as titania, 0.02% by weight (Example 2),
0.2% by weight (actual, sea side 3), L, [? The ponds containing ff1m% (Example 4) and 2.0% by weight (Example 5) were operated in the same manner as in Example 1 to determine the l3-G mixed color membrane filling property.

Example 6 000 g of copper-activated zinc sulfide green light-emitting phosphor was dispersed in 21 pure water, and the average particle size was 30 g.
Millimicron titania fine particles (P-25 manufactured by Nippon Aerosil Co., Ltd.) were added at a titania concentration of 0.02ffi1%. This was adjusted to pH 4.0 with dilute acetic acid, filtered, heated to 100°C, smoked, and crushed for 1 minute through a 400-mesh mesh to obtain the surface-treated phosphor of the present invention (1).

Next, evaluation was performed using the method shown in Example 1. B-G color mixing was performed by making a three-color phosphor pattern using conventional blue and red phosphors and checking the number of mixed blue phosphors that entered the green phosphor pattern.

Example 7 Gold, copper, aluminum activated zinc sulfide green emitting phosphor 10
00g was dispersed in 21 pure water, stirred well, and then 0.1 weight 96 of silica sol was added as 8102, and then titania sol (titanium oxide sol manufactured by Nichiryo Kagakuwa) was added so that it was 0.02 weight % as titania. . 10 more
% zinc sulfate aqueous solution as ln, after adding 0.1% Na
[The pH was adjusted to 8 with 1 tl aqueous solution. After filtering this, 100
It was dried at a temperature of 0.degree. C. and ground through a 400 mesh to obtain the surface-treated phosphor of the present invention.

The evaluation results of B-G color mixture and film filling properties are shown in Table 1.

Comparative Example 1 A phosphor was prepared in the same manner as in Example 1 except that titania was not attached.

Comparative Example 2 Fluorescent material No. 1 was prepared in the same manner as in Example 7 except that titania was not attached.

Comparative Example 3 A pond using silica sol instead of titania was treated with a phosphor in the same manner as in Example 1.

Table 1 Example B-G color mixture Film filling property 1 33 3, 5 2 37 3, 6 3 30 3, 4 4 25 3.2 5 17 3.0 6 40 2, 5 7 35 3, 4 Comparative example 1 42 3.6 〃2 42 3.5 〃3 42 3.7 [Effects of the Invention] When the surface-treated phosphor of the present invention is used for color cathode rays, it does not cause contamination with other color stripes or dots or other problems. With less color contamination and improved uniformity and fineness of stripes and dots, the overall quality of cathode ray tubes is significantly improved compared to conventional ones, and at the same time, the yield in the cathode ray tube phosphor film manufacturing process is improved. This has the effect of

Claims (4)

[Claims] (1) The average particle size of primary particles on the surface of the phosphor particles is 500.
A surface-treated phosphor characterized by adhering titania particles of millimicrons or less. (2) The average particle size of the primary particles of titania particles is 20 to 3
00 millimicron surface-treated phosphor according to claim (1). (3) A surface-treated phosphor according to claim (1), wherein titania particles are attached in an amount of 0.001 to 1.0% by weight based on the phosphor. (4) The surface-treated phosphor according to claim (1), wherein titania particles are attached to the surface of the phosphor particles using titania sol.