JPS5861547A - Cathode-ray tube for color display - Google Patents

Abstract

PURPOSE:To reduce the color differences among the luminous colors of a three- colored fluorescent screen, and make the fluorescent screen to have no color nonuniformities by making a light-blue luminous element by mixing a red phosphor, which is adjusted to have a specified chromaticity, with a red, a green and a blue phosphor. CONSTITUTION:In forming a light-blue or white luminous element which is one of the luminous elements of a three-colored fluorescent screen which emits light by receiving stimulations of cathode rays, the Eu concentration of a red phosphor (Y2O2S:Eu) is reduced to 1-3mol% so as to shift the color tone toward the yellow side and to adjust the chromaticity to x=0.600-0.620 and y=0.350-0.370. In addition, the above red phosphor is mixed with both a green phosphor (ZnS: CuAuAl or Zn2SiO4:MnAs) and a blue phosphor (ZnS:Ag). As a result, a fluorescent screen without any color nonuniformities can be obtained by decreasing the color differences among the red phosphor, the green phosphor and the blue phosphor.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cathode ray tube for color display that displays characters and figures.

Recently, high-resolution cathode ray tubes have become widely used in computer terminal equipment. The fluorescent surface of cathode ray tubes used for such purposes has a P22 phosphor, which is conventionally used in commercial television sets, or an edge wall light with Z,
8: CuAl or Zwa! 3: CuAuAl, Z as a blue fluorophore element, 8: A, Y as a boundary wall light element, 028: Eu is used as is. In addition, if the vertical scanning frequency of the screen is 60 Hz, which is normally used for color broadcast reception, when using a lower beam, Z, 2S, 04:M is used for the phosphor with a long afterglow time, that is, the edge wall light, as the end of the flicker pair. ,A.

Zn5 (POa) *: round or (ZflM g
)3(POa)2'Ma is used in combination with Rindoku or P22 phosphor.

These cathode ray tubes for displays do not necessarily require the same colors as the three primary colors used for normal color broadcast reception because what is displayed to the public is characters and figures, but the blue can be slightly mixed with white depending on the purpose. They are also made in blue, or in place of blue, in white. This is because the brightness of blue is lower than the brightness of green and red, making it difficult to see.

Edge wall light body (Z, 8:C') to front light body (Z,,S:A,)
uAl or z, S: CuAuAl or Z, 2S
IO4: M, A, ) and boundary wall light body (Y, 0,8:
E, also tf z,, (PO4), :M, again u
(21M, ), (PO4)2:M, ) is mixed in an appropriate amount to make it light blue or white to increase brightness and make it easier to see.

In this way, by mixing three types of phosphors with different emission colors,
When producing one light emitting element, there is a drawback that the color difference between the emitted colors is large and it is difficult to mix the phosphors uniformly, resulting in spot-like color unevenness.

In order to eliminate this drawback, the present invention uses a commonly used parting wall light material (Y2O, 8:Eu) Noiro 11 (X = 0.620 ~
0.650*)'=0.320~0.350) by decreasing the degree of roundness to move it toward the yellow side, and red phosphor (x=0.600~0.620 t y=Q , 350-
0.370) and the green phosphor and the blue phosphor to eliminate the color difference.

This will be explained in detail below.

When one of the light emitting elements is light blue or white,
Blue phosphor (Z, S:A,) and yellow phosphor (ZuCdS)
: Method of mixing CuAA and blue phosphor (Z, 8:
A, ) with green phosphor (Z, S: CuAuAl or "o
There are two methods: 2 SI O4'' Myr As ) and a red phosphor (Y, O□8:Eu).

Although the method of mixing yellow phosphor has the advantage of brightness and less color unevenness, it is not preferable because it contains cadmium. The method of mixing a blue phosphor with a green phosphor and a red phosphor involves mixing three types of phosphors, so it is difficult to mix them uniformly, and there may be problems between each phosphor. Because the color difference is large, color 2 tends to appear. Therefore, attempts have been made to form a phosphor surface by reducing the particle size of the phosphor or by performing ball milling for a long time, but these efforts have been insufficient.

In the present invention, we focused on the fact that the color tone changes by changing the Eu concentration of the red phosphor (Y2O2S:Eu), and by reducing the Eu yield from the conventional 3 to 5 mo1% to 1 to 30101%, the color tone is towards the yellow side. Shift the chromaticity to X=0.600~0.
620 ty--o, a 50-0.370.

This phosphor and green phosphor (Z, 8: C, A, AJ
Furthermore, when a light blue and white light-emitting element was formed by mixing 1d z,, s, Oa ""5Aa) and a blue phosphor (Z118:A,), a uniform color without unevenness was obtained. The color difference between each emission color is expressed as the distance between two points on the UC8 chromaticity diagram, but if the color tone of the red phosphor is made yellow, the color difference between both the green phosphor and the blue phosphor will be small. As a result, uneven color becomes less noticeable. Although the red phosphor (Y, 0,8:Eu) is an expensive phosphor, by reducing El, which is the most expensive material in this material, the red phosphor can be made cheaper.

Examples will be described below.

[Example 1] Blue phosphor Zts 8: Ag (X; 0.150
' Y """ O-070t "~0.169t
65% by weight of p-edge color phosphor Z,8: CllAt1AI (X=0.31
0 t Y=0.600su-0,129, v=0.3
76 average particle size 7μ) with 20% by weight red phosphor Y, 0.8
:Eu(x=0.610, y=0.360.

u = Q, 400, v = o, a 54 average particle size 5μ
) was mixed in an amount of 15% by weight and subjected to ball milling for 1 hour using pure water and a surfactant. After this, polyvinyl alcohol-4'V
A).

A fluorescent surface was formed using a slurry method using dichromated ammonium dichromated ammonium (ADC).

This light-emitting element produced a light blue fluorescent surface with no color unevenness.

Conventionally used red phosphor Y, 028: EuC
X-0,630, Y=0.330. u=0.442. V
= 0.347), the color difference is expressed as the distance (-hu)"+(aV)" between two points on the UC8 chromaticity diagram, so the color difference between green and red is When the boundary wall light of this embodiment is used, the color difference is 0.314, and when the boundary wall light of this embodiment is used, it is 0.272.The color difference is considerably reduced. Similarly, the color difference between blue and red is 0.356 to 0.33.
When the value is 0, the color difference becomes smaller. Therefore, it is very effective in eliminating color unevenness.

[Example 2] Blue phosphor Zys 8: Ag (x=o-150-
Y=0-070-u=h169, V=0.119 average particle size 8μ) 58% by weight, green phosphor Z, 8,04
:M, A, (X=0.20513""0.716,
u = 0.073, v = 0.384 average particle size 8 μ) at 30 coul%, red phosphor Yz 028 : E 1(x
=o, 610t Y=0.350, u=0.40
0, V=0.354, average particle size 5μ) were mixed in an amount of 12% by weight, and subjected to ball milling for 1 hour using pure water and a surfactant. Thereafter, a fluorescent surface was formed using the slurry method in the same manner as in Example 1. This light emitting element had a light blue color with no color unevenness, and no flicker appeared even when used at a vertical scanning frequency of 50 Hz.

As in Example 1, the conventionally used red phosphor Ys0
The color difference between 28=Eu and the green phosphor Z, 28,04:M, A is 0.371, and when the boundary wall phosphor of this example is used, it is 0.328. Therefore, the color difference is reduced and color unevenness no longer appears.

As described above, the present invention is very effective in producing a light blue or white color with a uniform fluorescent surface at low cost.

[Brief explanation of drawings]

Figure 1 is a CIE (X, V) chromaticity diagram of Example 1 of the present invention.
FIG. 2 is a UC8 chromaticity diagram of Example 1 of the present invention.

Claims (1)

[Claims] One of the three-color fluorescent surface light-emitting elements that emits light when stimulated with cathode rays is
CIE chromaticity x-0,600~0.620. )'=0.
350 to 0.370) IJium phosphor (Y, 0,8:E,), silver activated zinc sulfide phosphor (Z, 8:A,) and copper-aluminum phosphor Active or copper gold aluminum activated zinc sulfide phosphor (Z, 8: CuAj or Z, 8
A cathode ray tube for a color display, characterized in that it is a mixture of manganese and arsenic-activated zinc silicate phosphor (Zn2 r '' I 04 '' 8A).