JPH0739576B2 - Surface treated phosphor for cathode ray tube - Google Patents

Description

The present invention relates to a surface-treated phosphor for a cathode ray tube in which titania particles having an average primary particle size of 500 mm or less are attached to the surface of the phosphor particle for a cathode ray tube. . More specifically, it relates to a surface-treated phosphor for a cathode ray tube, which is preferably used for a fluorescent surface of a color picture tube and other cathode ray tubes.

[Conventional technology]

Usually used as a cathode ray tube fluorescent material (hereinafter, simply referred to as "fluorescent material" in the present specification) as a fluorescent film by coating each color in a stripe shape or a dot shape on a face plate to be used for a color picture tube. .

In order to increase the adhesive force to the glass surface of the fluorescent body, prevent color mixture (cross contamination) to the other color light emitting fluorescent film, and obtain uniform and dense stripes or dots,
Various surface treatments have been applied. However, silicate compounds, phosphate compounds, oxides of various metals, and the like are conventionally known as such surface treatment substances. Above all, Si
O ₂ is effective for surface modification of powder containing fluorescent material, especially Si
It is known that O ₂ sol can be effectively used as a surface treatment agent.

However, with the demand for improved performance such as high definition of color picture tubes, the coating characteristics required for phosphors are becoming more and more severe every day, and it is the current situation that conventionally known surface treatment technology is no longer able to meet the demand. is there.

[Problems to be solved by the invention]

Therefore, an object of the present invention is to have sufficient adhesiveness to a glass surface, to prevent cross contamination (color mixing) between phosphors having different emission colors, and to realize uniformity and denseness of a coating film. The object is to provide a surface-treated phosphor having characteristics.

Therefore, the present inventors have conducted various searches for surface treatment materials and their treatment methods in order to achieve the above objects, and as a result of repeated studies, the phosphor surface-treated with titania particles is significantly more remarkable than conventionally known phosphors. The present invention has been completed by finding that it is excellent and that the above-mentioned object can be achieved thereby.

[Means for solving problems]

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

The present invention will be described in detail below.

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

After the fluorescent particles are dispersed in approximately 2 to 5 times the amount of deionized water, titania particles or titania sol dispersed in a solvent (for example, water, alcohol, etc.) is added and then the pH of the dispersion is
The titania is adsorbed on the surface of the phosphor by controlling the value of 3 to 9. After filtering this and washing with water, etc.
Dry at 80 ° C to 250 ° C, then disperse and finish by passing through a screen of 300 mesh or more.

At the same time that the titania particles are attached to the fluorescent particles,
Other surface treatments, such as SiO ₂ sols uniform adhesion of can also may perform such adhesion of zinc hydroxide compounds, also possible to perform these additional processing in a separate step before or after the titania surface treatment process .

As the "titania particles" used here, commercially available products can be used as they are without any problem. Examples of commercially available products include titanium oxide sol manufactured by Nissan Kagaku Co., Ltd., titanium oxide P-25 manufactured by Nippon Aerosil Co., Ltd., and the like.

The amount of the titania particles attached to the phosphor 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. This is because by setting it in this range, a sufficiently satisfactory color mixing prevention effect and film filling performance can be obtained.

Furthermore, in the present invention, the titania particles attached to the fluorescent particles have an average primary particle size of 500 mm or less. By setting the average particle size to 500 millimicrons or less, the adhesive force with the phosphor can be ensured, and the aggregation of titania particles on the phosphor particles can be prevented. More preferably, the average particle size of the primary particles of the titania particles is 20 to 300 millimicrons. This is because it is possible to increase the surface area of the titania particles at 20 to 300 mm compared to the case where a titania particle layer is formed in a film on the phosphor when a titania sol of 20 mm or less is used. . The average particle diameter of the primary particles referred to here is obtained as follows.

Put 100cc of 0.2wt% sodium hexametaphosphate into a 200cc glass beaker and add 0.1wt% of titania to it.
Titania sol or titania powder is added so that it becomes 0.01 wt%. While stirring with a stirrer, disperse for 30W3 minutes with a throw-in type ultrasonic frame breaker (Kaiyo Denki TA-4280 type), and this liquid is kept in a centrifugal sedimentation method particle size analyzer SA-CP3 (manufactured by Shimadzu) MEDIAN DIAM obtained by particle size measurement with this device
Was defined as the average particle size.

The "fluorescent particles" that can be used here include all that can be used for color cathode ray tubes. For example, zinc sulfide-based, rare earth-activated oxide-based and rare earth-activated oxysulfide-based phosphors can be mentioned, more specifically, ZnS: Ag, ZnS: C.
u, ZnS: Au, ZuS: Cu, Au, Zn 2 SiO 4: Mn, Zn 3 (PO 4) 2: Mn, Y 2 O 3: E
u, Y ₂ O ₂ S: Eu, YVO ₃ : Eu and the like can be mentioned.

It should be noted that the surface-treated phosphor of the present invention may contain phosphor particles to which a pigment is further attached for the purpose of improving the contrast of the phosphor film.

The phosphor of the present invention, which has been surface-treated by the above method, is PV
Color consisting of dispersing in a slurry consisting of A, dichromate, water, and a surfactant, spin coating this on a cathode ray tube panel, and then forming a stripe or dot pattern by an optical 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 in a color cathode ray tube, stripes of other colors, contamination of dots or contamination from other colors is small, and stripes and dots are excellent in uniformity and fineness, and the cathode ray seen as a whole. At the same time that the quality of the tube is better than before,
It has the effect of improving the yield in the fluorescent film manufacturing process of the cathode ray tube. This effect is particularly remarkable when fluorescent substance particles to which a pigment having gelatin as a binder is attached are used as raw materials.

Example 1 A blue luminescent silver activated zinc sulfide phosphor with cobalt blue pigment was prepared by a conventionally known method disclosed in JP-A-53-5088, using gelatin and gum arabic as an adhesive. This is because 0.4% by weight of gelatin, 0.4% by weight of gum arabic and 1.5% by weight of cobalt blue are attached to the fluorescent substance, and dried,
It was crushed. 1000 g of this fluorescent substance with pigment was dispersed in 2 liter of pure water, and titania sol having an average particle size of 70 mm (Nissan Chemical Co., Ltd., titanium oxide sol) was added as 0.1% by weight as titania while stirring well. The pH is lowered to 4.0 with diluted acetic acid, filtered, and dried at 100 ° C to 400
After passing through a mesh, it was pulverized to obtain a 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 in.

[Coating method]

The coating is the same as the method for manufacturing a color cathode ray tube by the slurry method, and is performed by the following steps. The fluorescent substance is dispersed in a coating liquid mainly containing water, polyvinyl alcohol, dichromate and a surfactant. First, an ordinary green phosphor that is generally used is first applied by spin coating to a color cathode ray tube panel that has been subjected to a black matrix or precoat treatment, and then dried. This is irradiated with ultraviolet rays through a shadow mask, washed with hot water spray, and dried to obtain a green phosphor dot pattern at a predetermined position.

Next, a pattern of the blue phosphor of the present invention is formed at a fixed position of the color cathode ray tube in the same manner as the panel on which the green phosphor pattern is formed. Then, in the same manner, a conventional ordinary red phosphor pattern is formed at a predetermined position.

[BG mixed color test]

The BG color mixture was determined by measuring the number of blue phosphors on one dot (diameter 180 mm) while the blue phosphor mixed on the green phosphor dots was illuminated with ultraviolet light.

[Membrane filling]

The film filling property was evaluated on a scale of 5 out of 5 by sensitizing the dried glass, which was obtained by coating the whole surface of a panel glass for a cathode ray tube with a fluorescent material and observing the dried material with a transmitted light.

Examples 2 to 5 Use amount of titania sol in Example 1 As titania
0.1 wt% is 0.02 wt% (Example 2), 0.2 wt% (Example 3), 1.0 wt% (Example 4), 2.0 wt%
The same operation as in Example 1 was carried out except that (Example 5) was used, and B
-G color mixture and film fillability were determined.

Example 6 1000 g of copper-activated zinc sulfide green light-emitting phosphor was dispersed in 2 liters of pure water and dispersed in water while stirring well, and titania fine particles having an average particle size of 30 mm (P-2 manufactured by Nippon Aerosil Co., Ltd.).
5) was added as titania in an amount of 0.02% by weight. This was adjusted to pH 4.0 with dilute acetic acid, filtered, and kept at 100 ° C.
After being dried in, the mixture was pulverized through 400 mesh to obtain the surface-treated phosphor of the present invention.

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

Example 7 Gold, copper and aluminum activated zinc sulfide green light emitting phosphor 1000
Disperse g in 2 liters of pure water and add silica sol to S while stirring well.
0.1% by weight of iO ₂ was added, and then titania sol (titanium oxide sol manufactured by Nissan Chemical Industries, Ltd.) was added as titania so as to be 0.02% by weight. Further 10% zinc sulfate aqueous solution
After adding 0.1 wt% as Zn, the pH was adjusted to 8 with an aqueous NaOH solution. This was filtered, dried at 100 ° C., and pulverized through 400 mesh to obtain the surface-treated phosphor of the present invention.

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

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

Comparative Example 2 A phosphor was obtained in the same manner as in Example 7 except that titania was not attached.

Comparative Example 3 A phosphor was obtained in the same manner as in Example 1 except that silica sol was used instead of titania.

[Advantages of the Invention] The surface-treated phosphor of the present invention, when used in a color cathode-ray tube, has less stripes of other colors, less contamination of dots or contamination from other colors, and stripes, dot uniformity, and compactness. In addition, the quality of the cathode ray tube as a whole is significantly improved as compared with the conventional one, and similarly, the yield in the fluorescent film manufacturing process of the cathode ray tube is improved.

Front Page Continuation (72) Inventor Tetsuo Suzuki 1060 Narita, Odawara, Kanagawa Kasei Optonics Co., Ltd. Odawara Plant (56) References JP-A-59-105254 (JP, A) JP-A-59-36182 (JP, JP, 36-182) A) Japanese Patent Publication Sho 39-17874 (JP, B1)

Claims (4)

[Claims] 1. A surface-treated phosphor for a cathode ray tube, wherein titania particles having an average primary particle diameter of 500 mm or less are attached to the surface of the phosphor particles for a cathode ray tube. 2. The average particle size of the primary particles of the titania particles is
The surface-treated phosphor for a cathode ray tube according to claim (1), which has a size of 20 to 300 mm. 3. The range from 0.001 to 1.0 with respect to the phosphor for the cathode ray tube.
The surface-treated phosphor for a cathode ray tube according to claim (1), characterized in that a weight% of titania particles are attached. 4. The surface-treated phosphor for a cathode ray tube according to claim 1, wherein the titania particles are attached to the surface of the phosphor particles for a cathode ray tube by using a titania sol.