JPH0267391A - Cathode ray tube for color display - Google Patents

Abstract

PURPOSE:To provide a uniform yellow fluorescent screen free from Cd to thereby realize a reduction in cost for recovery of used cathode ray tubes and for anti-pollution measures, etc., by a constitution wherein a yellow light emitting element is combined with phosphor particles of a specified color in a cathode ray tube having a trichroic fluorescent screen. CONSTITUTION:In a cathode ray tube having a trichroic fluorescent screen which will emit light by cathode-ray stimulation, one of the light emitting elements is formed from a phosphor prepared by attaching small particles of a Y2O2S:Du, Y2O3:Eu or YVO4:Eu phosphor to the surface of a ZnS:Au,Al phosphor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color display cathode ray tube for displaying characters and figures, and particularly to its phosphor screen.

[Conventional technology]

Traditionally, the phosphor screens of color display cathode ray tubes used for displaying computer terminals, measuring instruments, and control equipment are
The three color phosphors commonly used in commercial television are Z, Sac, /Ift phosphors or ZnS:CuA, Aρ phosphors for green-emitting phosphors, and Z, S: for blue-emitting phosphors. Ag phosphor, Y2O for red emitting phosphor
2S:Eu phosphor was used. However, recently, when the television is not used for commercial broadcast reception but is used for the purpose of displaying characters and graphics, it is not necessarily necessary to use the three primary colors of green, blue, and red for conventional color broadcast reception, red 3
Things that use color have begun to be created. The reason for this is that even when characters and figures are displayed in blue, blue has low visibility and is very difficult to see.As a result, monochromatic blue display is often not used. Therefore, by using yellow, which has high visibility, instead of blue, and using the other two colors as conventional green and red light emitting elements, the color discrimination and brightness are sufficient, and it is sufficient for three-color display. performance. For this reason, color display cathode ray tubes that display three primary colors are sometimes used. However, as this yellow luminescent material, the conventional (zIlcd)
S:Cu.

Since there is only AJ2 phosphor and it contains CD, it requires a great deal of cost to collect used cathode ray tubes, so green-emitting Z, Sac, Au, AJ phosphors and red-emitting Y2O2S:Eu phosphor are used. A yellow light-emitting element was created by mixing the two bodies.

The phosphor screen of a cathode ray tube for color displays is generally made by forming a slurry of green-emitting phosphor suspended in polyvinyl alcohol and ammonium dichromate solution after forming light-absorbing black matrix holes on the inside of the face panel. is applied to the inner surface of the panel, dried with an infrared heater, exposed to ultraviolet light with a shadow mask attached, and developed with hot water to form a phosphor film pattern. A three-color fluorescent film pattern is formed, an organic film is formed on the backside of the pattern, and an aluminum vapor deposition film is then formed.

[Problem to be solved by the invention]

Conventionally, two types of phosphors, green and red, are mixed to form one light-emitting element, so when the two types of phosphors are dispersed in a slurry, fine particles agglomerate, resulting in red and red phosphors. Alternatively, the phosphor film is made up of aggregates of green phosphor particles with a size of several tens to several hundreds of microns, which has the disadvantage that it does not appear as a negative yellow color but instead appears as a mixture of green and red.

[Means to solve the problem]

The present invention provides a cathode ray tube having a three-color phosphor screen that emits light upon cathode ray stimulation, in which a yellow light emitting element is used as a yellow-green light emitting ZS:
Au, Aj! On the surface of the phosphor particles, small particles of red light emitting Y2O2S:Eu phosphor or YVO4:
E. A phosphor film is formed using mixed color phosphor particles to which phosphors are attached.

〔Example〕

Next, the present invention will be explained by examples.

Example 1 As shown in FIG. 1, a black matrix 2 for light absorption is first applied to a glass panel 1 using a conventional method.
form. The green light emitting element has a luminous chromaticity of x=0.
280. y=Q, 600 ZfIS: Cu, Au, A,
Using ff phosphor 5, the red light emitting element has an emission chromaticity of x=0.
．． 630. y=0.330 Y2O2S:E, phosphor 6
A three-color phosphor film pattern was created using a slurry method using a yellow emitting element of Z, S:A, and a phosphor with small particles of Y2O2S:E and phosphor particles 4 attached to the surface of Af phosphor particles 3. After forming an organic film on the back side of A,
A three-color phosphor screen on which a vapor-deposited film 7 of R was formed was formed. The phosphor used to form the yellow light-emitting element was Z, S, which emitted yellow-green light with an average particle size of 8 μm and an emission chromaticity of x=0.370° and y=0.560.
:A.

100 parts of Aρ phosphor was dispersed in a gelatin solution, the average particle size was 1.5μ, and the luminescence chromaticity was x=0.630゜y=0.330.
A phosphor was prepared by dispersing 20 parts of a red-emitting Y202S:Ea phosphor in a polyvinylprolidone solution, and mixing and stirring the two phosphors to precipitate them. This precipitated phosphor forms small particles of Y on the surface of the Z, S: Au, Aρ phosphor 3 due to the action of gelatin and polyvinylpyrrolidone.
202S: Eu phosphor 4 is attached. The yellow light emitting element created using this phosphor has a polarity of X=0.42
5. At y=0.515, an even -like yellow phosphor screen was obtained. As shown in Figure 2, this phosphor screen also emits light in a color close to yellow. S:A,,A,! Y2O2S:Eu phosphor 9 has small particles and emits red light because it uses O phosphor 8.
A yellow light-emitting element can be obtained by simply mixing the light emitted by a small amount. Therefore, by attaching a red-emitting phosphor with a very small particle size to the surface of a yellow-green Z, S:Au, Al phosphor, it was possible to emit yellow light. The small particles emitting red light were attached to the phosphor emitting yellow-green light, resulting in a yellow phosphor screen with red and yellow-green indistinguishable from each other with the naked eye.

Example 2 As shown in FIG.
205, y=0.680 Z n2 S I O4:M
Using the fi phosphor 12, the red light emitting element has an emission chromaticity x=0.
．． 630. Y20□S of y=0.330: Eu phosphor 9
A three-color phosphor screen was created using a phosphor 10 in which small particles of YVO,:E, ,Al phosphor were attached to the surface of the yellow light-emitting element Z, S: A, , A, & phosphor. It was prepared in the same manner as Example 1. The phosphor formed in the yellow light emitting element has an average particle size of 8μ1 and an emission chromaticity x=0.370. y==Q, 56
Z, S: A, AJI phosphor 100 with 0 yellow-green light emission
part and average particle size 1.5 μ2 Emission chromaticity x = 0.630, y
It was prepared in the same manner as in Example 1 using 15 parts of a red-emitting YVO4:Eu phosphor of =0.330. The yellow light emitting element created in this way has an emission chromaticity of x=0.410.3
7=0.520, a -like yellow fluorescent film was obtained. As shown in Figure 2, this three-color phosphor screen has a large difference in chromaticity between the green light-emitting element, the yellow light-emitting element, and the red light-emitting element.
The fluorescent screen has clear color distinctions and is easy to see.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to obtain a fluorescent screen with a similar yellow color without containing CDs, which significantly reduces costs such as strict collection of used cathode ray tubes and pollution treatment, and also improves display efficiency. This makes it a very useful cathode ray tube for color displays.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the phosphor screen structure of Example 1 of the present invention;
FIG. 2 is a diagram showing the chromaticity of Example 1 and Example 2. 1...Panel, 2...Black matrix, 3...
・Zl, S: Au, Al phosphor, 4-Y202S
:E, small particle phosphor, 5・Z, S: C,, AuA
f! , 6-Y202S:Eu phosphor, 7・A,
R film, 8...ZnS:Au, Affl phosphor chromaticity point, 9...Y2O2S:E, phosphor chromaticity point, 10.Zf
iS:A, chromaticity point of phosphor with Y20□S:Eu small particle phosphor attached to Al phosphor, 11...Z, S:C
,,A,,Al phosphor chromaticity point, 12-Zf12S.

Claims (1)

[Claims] In a cathode ray tube that has a three-color phosphor screen that emits light upon cathode ray stimulation, one of the light emitting elements has small particles of Y_2O_2S:Eu or Y_2O_ on the surface of a ZnS:Au,Al phosphor.
3: Eu or YVO_4: A cathode ray tube for a color display, characterized in that it is formed using a phosphor to which Eu phosphor is attached.