JPH0625353B2 - Color cathode ray tube - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a color cathode ray tube, and more particularly to a fluorescent surface thereof.

[Technical background of the invention and its problems]

Usually, on the fluorescent surface of a color cathode ray tube, there are regularly arranged dot-shaped or stripe-shaped groups of phosphors that emit red, green, and blue light, and if necessary, non-emissive light-absorbing substances are placed in the spaces between these phosphors. It is covered. Conventionally, in such a color cathode ray tube, in order to improve the contrast of the screen, it is known that a fluorescent substance is attached or mixed with a pigment having a color tone substantially the same as the emission color of the fluorescent substance to reduce the external light reflectance. ing. However, in such a method, for example, JP-A-56-141149
The scattered electrons scattered in the shear mask and the metal back layer described in the publication, and the reflected electrons in which the electron beam scanned a little larger than the effective fluorescent surface is reflected between the shear mask and the inner surface of the side wall of the panel. As a result, it has not been possible to sufficiently improve the reduction in the contrast of the screen caused by the abnormal light emission of the phosphor.

[Object of the Invention]

It is an object of the present invention to obtain a color cathode ray tube which has a significantly improved screen contrast, high image quality and high brightness.

[Outline of Invention]

In general, for example, JP-A-52-12561 discloses Zn
The S-CdS-based phosphor is described as a color cathode ray tube with a fluorescent surface in which the current-luminance characteristics of the phosphor are changed by doping a small amount of impurities such as Ni. Nor is there any mention of phosphors to be combined. Also, U.S. Pat.No. 3,294,569 describes a penetration type cathode ray tube using a phosphor obtained by doping a ZnS: Ag blue phosphor with Co, but regarding the optimum doping amount in other cathode lines. Is not listed at all. On the other hand, regarding a red fluorescent material, especially a rare earth type fluorescent material, in Japanese Patent Publication No. 47-13243, Y ₂ O ₂ S / Eu is added with Tb of 2 to 4.
It is said that the luminous efficiency of the phosphor can be improved when it is doped with 0 ppm, but there is no description about other effects as a color cathode ray tube using such a phosphor.

As mentioned above, it is individually known that a small amount of ferromagnetic metal or rare earth metal is doped into a fluorescent substance, but when such a fluorescent substance is used in a color cathode ray tube, in-tube scattered electron It is difficult to set optimal conditions for the optimum doping amount and the content of the structure, because the relationship between this and the abnormal emission of the fluorescent surface due to reflected electrons is unknown.

As a result of the present inventors paying attention to the above-mentioned points, as a result, the green light emitting phosphor and the red light emitting phosphor, when using a phosphor in which at least one of the current luminance characteristic and the voltage luminance characteristic is changed, It has been found that abnormal light emission on the light surface can be most efficiently reduced without substantially lowering the brightness of the color cathode ray tube, and that a black level color tone of a reproduced image can be obtained without incongruity.

This seems to be due to the following reasons. That is, blue,
When viewing the green and red phosphors in terms of their luminosity, assuming that the green luminophore is 100, the red luminophore is about 30, the blue luminophore is 20, and the green luminophore is the most luminosity. Is large. Therefore, the deterioration of the black level due to the occurrence of abnormality should be improved by taking measures against the green phosphor having the highest visibility. However, in this case, the black reproduced image becomes a reddish purple color, which gives an unnatural feeling, which is not preferable.

The present invention relates to a green-emitting fluorescent substance as Fe, Co, Ni as a ferromagnetic metal.
At least 0.1 to 500 ppm of the phosphor is doped into the red-emitting phosphor as a rare earth metal.
15 to 60 ppm of at least one of Tb, Er and Pr with respect to the phosphor
By using the doped one, the emission of each of the green and red phosphors due to scattered electrons and reflected electrons is reduced, the contrast reduction of the screen is improved, and a strange feeling of a reproduced black image is generated. It is a high-intensity color cathode ray tube with no problems.

The green light emitting phosphor applied to the present invention includes ZnS / Cu,
Al, (ZnCd) S / Cu, Al, ZnS / Au, Al, ZnS / Au, Cu, Al and the like can be used. Fe, Co, Ni, and the like can be used as the ferromagnetic metal that is doped into these phosphors.
The doping amount is 0.1-500 pp with respect to the phosphor.
m, preferably 0.5 to 50 ppm.

The red fluorescent material applied to the present invention includes Y ₂ O ₂ S / Eu, Y ₂
O ₃ / Eu, Gd ₂ O ₃ / Eu, YVO ₄ / Eu, Gd ₂ O ₂ S / Eu can be used. Er, Tb, Pr and the like can be used as the rare earth metal with which the fluorescent substance is doped. Further, the doping amount is 15 to 60 ppm, preferably 20 to 4 with respect to the phosphor.
It is 0 ppm.

Example of Invention

 Specific examples of the present invention will be described below.

Example 1 First, the following conventional phosphor was used as a comparative example (A).

Blue Fluorescent material ZnS / Ag, Cl Green fluorescent material ZnS / Cu, Al Red fluorescent material Y ₂ O ₂ S / Eu Next, as Comparative Example (B), ZnS / Cu, Al was doped with Ni at 3 ppm as shown below. A fluorescent body was used.

Blue Fluorescent substance ZnS / Ag, Cl Green fluorescent substance ZnS / Cu, Al + 3ppm Ni doping Red fluorescent substance Y ₂ O ₂ S / Eu Next, as a comparative example (C), Y ₂ O ₂ S / Eu is doped with 30 ppm of Tb. The following fluorescent substance was used.

Blue Fluorescent material ZnS / Ag, Cl Green fluorescent material ZnS / Cu, Al Red fluorescent material Y ₂ O ₂ S / Eu + 30 ppm Tb doping Further, as an embodiment (D) according to the present invention, ZnS / Cu, Ni with 3 ppm, The following phosphor was used in which Y ₂ O ₂ S / Eu was doped with Tb at 30 ppm.

Blue Fluorescent material ZnS / Ag, Cl Green fluorescent material ZnS / Cu, Al + 3ppmNi doping Red fluorescent material Y ₂ O ₂ S / Eu + 30ppmTb doping In each of the above fluorescent material combinations, 14 inch type panel inner surface A fluorescent surface was formed by the method, and a color cathode ray tube was manufactured by an ordinary method.

White brightness of such a 14-inch color cathode ray tube (9300 ° K + 27MP
We measured the total current of the cathode = WIb) and the brightness of the dark area required to obtain the brightness of 32ft for the white color of CD). As shown in Fig. 1, the scanning width for displaying the white bar of the electron beam is 23.8 mm in the horizontal axis (X) direction with the vertical axis (Y) of the fluorescent surface as the center, and the white at the center point (O). When the brightness is set to 300 μA as the total current of the cathode, the horizontal axis from the center (10) of the fluorescent surface
The dark area brightness of the black level brightness at points (A) and (B) separated by 35 mm and 70 mm in the (X) direction was defined. Furthermore, with the color cathode ray tube mounted
We also evaluated the image quality of black-level color tones by 10 boys in their 20s and 40s. The evaluation results of this fluorescent surface are shown in Table 1.

As is clear from Table 1, Comparative Example (B) improves only abnormal emission of the green phosphor due to scattered electrons and reflected electrons, so that the black level color tone becomes reddish purple, and the screen Although the reduction in contrast is improved, the image quality of the black level is evaluated as Δ because it gives a strange feeling. In Comparative Example (C), only the abnormal light emission of the red fluorescent substance was improved, and therefore, the reduction rate of the dark part luminance was slight due to the reason described above. On the other hand, in the color cathode ray tube of Example (D) according to the present invention, a decrease in white luminance is slightly visible, and in order to improve both the abnormal light emission of the green and red fluorescent materials. However, the color tone of the black level is bluish if it says, and for the reasons described above, there is no discomfort even in the image evaluation of the black level, and there is a color cathode-ray tube that has significantly reduced the contrast of the screen. Was obtained.

Example 2 Similar to Example 1, as Comparative Example (E), blue phosphor ZnS / Ag, Cl green phosphor ZnS / Cu, Au, Al red phosphor Y ₂ O ₃ / Eu Comparative Example ( F) as a blue phosphor ZnS / Ag, Cl green phosphor ZnS / Cu, Au, Al + 20ppmCo-doped red phosphor Y ₂ O ₃ / Eu As a comparative example (G), a blue phosphor ZnS / Ag, Cl green phosphor ZnS / Cu, Au, Al red phosphor Y ₂ O ₃ / Eu + 30 ppm Er doping As an example (H) according to the present invention, a blue phosphor ZnS / Ag, Cl green phosphor ZnS / Cu, Au, Al + 20ppmCo doping red fluorescent material Y ₂ O ₃ / Eu + 30ppmEr doping was used to form a fluorescent surface on the inner surface of a 14-inch panel, and a color cathode ray tube was manufactured by an ordinary method. Table 2 shows the same evaluation results as in Example 1 of this fluorescent surface.

As is apparent from Table 2, as in Example 1, the color cathode ray tube of Example (H) according to the present invention has no discomfort in the color tone of the black level, and is a color cathode ray tube in which the contrast reduction of the screen is significantly improved. was gotten.

〔The invention's effect〕

As described above, according to the present invention, by using a fluorescent material in which a ferromagnetic metal or a rare earth metal is doped to a green light emitting fluorescent material and a red light emitting fluorescent material, a fluorescent material by scattered electrons or reflected electrons in a tube is used. The abnormal light emission of the layer can be improved, and the color tone of the black level can be improved to a color that does not give a sense of incongruity, so that it is possible to obtain a color cathode ray tube with higher contrast, higher image quality, and higher brightness than the conventional color cathode ray tube. You can

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining measurement points of black level luminance on the fluorescent surface.

Claims (1)

[Claims] 1. At least one of Fe, Co, and Ni as a ferromagnetic metal is added to a green light-emitting phosphor on a fluorescent surface that emits light by cathode ray stimulation.
As a rare earth metal for zinc sulfide or zinc cadmium sulfide-based phosphors and red-emitting phosphors doped with 1 to 500 ppm
A color cathode ray tube comprising: a europium-activated rare earth-based phosphor doped with at least one of Tb, Er, and Pr at 15 to 60 ppm.