JPS62106984A - Cathode ray tube - Google Patents

Abstract

PURPOSE:To provide a cathode ray tube having low shadow luminance and high green monochromatic luminance, which comprises a panel having a particular green luminescent phosphor deposited thereon and an electron gun adapted for projecting an electron beam against the panel. CONSTITUTION:A layer contg. 0.005-1.0pts.wt. (in terms of cobalt atom) cobalt oxide and 0.1-5ppm of nickel is provided on the surface of 100pts.wt. matrix phosphor comprised of at least one member selected from a zinc (cadmium) sulfide phosphor activated with copper and aluminum and a zinc sulfide phosphor activated with copper, gold, and aluminum to obtain a green luminescent phosphor. A shadow mask 9 having an opening 8 is disposed opposite to the inside of a panel 3 having a phosphor layer 7 formed on the inside thereof and comprised of a red luminescent phosphor, a blue luminescent phosphor and the green luminescent phosphor which have been regularly deposited, while an electron gun 6 is disposed within a neck 5 of an enclosure comprised of the panel 3, a funnel 4, and a neck 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a cathode ray tube, and particularly to a phosphor screen thereof.

[Technical background of the invention and its problems]

Cathode ray tube 1 For example, the phosphor screen of a color picture tube has a dot-like or strip-shaped phosphor layer that emits red, green, and blue light, and if necessary, a non-emission-absorbing material is coated between these phosphor layers. . Conventionally, in order to improve the contrast of the screen in such color picture tubes, it has been known to reduce the reflectance of external light by attaching or mixing a pigment with approximately the same color tone as the luminescent color to the phosphor. ing.

On the other hand, the green-emitting phosphors of conventional color picture tubes include Zn'S:Cu, AQ, ZnS:A as sulfide phosphors.
u, AQ.

ZnS: Cu, AQ + ZnS:Au, AQ,
ZnS:Cu, Au, AQ, (Zn,Cd)S:C
u, AQ, etc. are used. However, these sulfide phosphors are generally highly efficient and give high brightness, which is preferable in this respect, but on the other hand, because they shine well even with weak scattered electrons, the problem is that the brightness in dark areas of the image becomes high, leading to deterioration of contrast. be.

By the way, as already mentioned, there is a known method of attaching or mixing pigments to phosphors in order to reduce the reflectance of external light, but with this method, it is not possible to efficiently reduce the dark area brightness due to scattered electrons. I can't.

This seems to be due to the following reasons. In other words, in conventional phosphors to which pigments are attached or mixed, the pigment particles are only physically attached to the surface of the phosphor, and as a result, the luminous efficiency of the phosphor (the increase in brightness with respect to the increase in the voltage applied to the anode) It is thought that this is because the phosphor particles do not have selective suppressing properties against incident scattered electrons, even though the ratio) has decreased.

In addition, in order to improve the deterioration of image contrast caused by scattered electrons, the applicant and the same applicant added small amounts of Ni and Co to the surface layer of the green-emitting zinc sulfide phosphor.
pingL/, a method for suppressing light emission due to scattered electrons (
Patent Application No. rT159-53519) has been filed.

This method measures the voltage characteristics of the phosphor by codoping.

Furthermore, by controlling the current characteristics of each of the phosphors by Nidoping, the purpose is to take advantage of both characteristics and selectively suppress the influence of scattered electrons. However, for example, if Co is 10ρ m HN 1
0.75ppm was simultaneously baked at 700℃ for 45 minutes.
Although a synergistic effect can be obtained in the brightness of the opening L section, there is a drawback that the brightness of the green color decreases more than the synergistic effect.

(JS Thousands Association) Table 1 The reason for the above phenomenon is that due to co-doping, some of the Ni that is easily doped is doped into the interior of the phosphor, reducing the luminous efficiency of the phosphor. .

The dark area brightness is determined by using a 30×10G white screen in the upper half of the screen and an anode voltage of 26. OKV, Total current = 5
When the white screen was reproduced at 00 μA and the white screen was covered with black paper, the brightness of a point 30 mm below the edge of the screen was measured.

[Purpose of the invention]

The present invention was made in order to eliminate the conventional drawbacks,
An object of the present invention is to provide a cathode ray tube having a phosphor screen with low dark area brightness and high green monochromatic brightness.

[Summary of the invention]

The present invention provides a cathode ray tube comprising a panel on which a green-emitting phosphor based on zinc sulfide is adhered, and an electron gun for projecting an electron beam onto the panel, in which the green-emitting phosphor is attached to the surface of the matrix. A cathode ray tube characterized by having a layer containing cobalt oxide and nickel.

According to the present invention, it is possible to realize a cathode ray tube having a phosphor screen with low brightness in dark areas and high monochromatic green brightness.

In the present invention, the content of cobalt oxide contained in the containing layer is preferably within the range of o,oos to 1.0 parts by weight, based on 100 parts by weight of the base material, in terms of cobalt atoms. If the amount is less than 0.005 parts by weight, the effect of lowering dark area brightness is extremely small. If it exceeds 1.0 parts by weight, luminance will decrease. A more preferable range is 0.01 to 0.41 parts by weight.

In the present invention, the content of nickel contained in the content layer is preferably within the range of 0.1 to 5 ppm. o,lppm
If it is less than 1, the effect of lowering dark area brightness is small. When the amount exceeds 5 ppm, the effect of reducing brightness in dark areas is saturated, and the luminance of light emission decreases. A more preferable range is 0.3 to 3 ppm.

The host phosphors applied in the present invention are copper and aluminum activated zinc sulfide phosphor, copper, gold and aluminum activated zinc sulfide phosphor, copper and Shiohiro activated zinc sulfide phosphor copper and aluminum activated zinc sulfide cadmium phosphor,
at least one of the following.

[Embodiments of the invention]

(Example 1) ZnS with average particle size LO μ washed with water and dispersed in bead mill:
Prepare 500 g of C″u,A Q phosphor.Pour 2.5Q pure water into a beaker and add the phosphor while stirring.

Next, Co CQ 2・61120, a = 0.1
g, b=0.202g, C=0.404g d
=0.808 g, e=1.616 g, f=2.02
g.

Eight types of sample needles were prepared, each containing g = 8.282 g and h = 20.2 g. ZnSO4/7 for each
) 120 800g and further 1% NH,OH
The pH is maintained at 8 to 8.5 with an aqueous solution, and a mixed precipitate of cobalt hydroxide and zinc hydroxide is attached to the phosphor. Next, after washing several times with pure water, drain the supernatant liquid,
Furthermore, 1.8 x 10-3 g of NiSO4.711□0 was added and kneaded into a paste. Dry this pasty mixture normally.

Further, by baking at 700° C. for 60 minutes and processing in a conventional manner, eight types of phosphors having layers containing cobal oxide 1- and nickel are obtained. The content of nickel in the containing layer is 0.75 ppm, and the content of cobalt oxide is 100 ppm in the base layer.
Sample A = 0.005 parts by weight, B = 0.00 parts by weight in terms of cobalt atoms. Old parts by weight, C=0.02 parts by weight, o=o
, oi parts by weight, E=0.08 parts by weight, F=0.1 parts by weight,
G=0.41 parts by weight, r(=1.0 parts by weight).

FIG. 1 is a schematic cross-sectional view of a phosphor according to the present invention.

The surface of the host phosphor 1 has a content of 2.

These phosphors were dispersed in a slurry containing ammonium dichromate, polyvinyl, alcohol, and various additives, and a color cathode ray tube was manufactured using a conventional method. As a comparison, we also fabricated a cathode ray tube using the same host phosphor but without cobalt oxide or nickel.

Figure 2 is a schematic cross-sectional view of the cathode ray tube of the present invention.
An electron gun 0 is disposed inside the panel 1, and a phosphor layer 2 in which a red-emitting phosphor, a blue-emitting phosphor, and a green-emitting phosphor are regularly deposited is formed on the inner surface of the panel 1. A shadow mask (9) having an aperture (8) is disposed on the inner surface of the panel, and the electron beam emitted from the electron gun 0 passes through the aperture of the shadow mask (9) to which an anode voltage is applied, and fluoresces. It collides with the body layer (■), causing phosphors of various colors to emit light.

FIG. 3 shows the relative luminance characteristics of these various cathode ray tubes with respect to the voltage applied to the anode.

As shown in Figure 3, those containing cobalt oxide are
The brightness for high applied voltages is high, and the brightness for low applied voltages is lower. The content of cobalt oxide is 1.0 parts by weight per 100 parts by weight of the base material in terms of cobalt atoms.
If the content of cobalt sulfide exceeds 0.00 parts by weight, the brightness will decrease significantly when high voltages are applied, which is not desirable for practical purposes. No decline is seen. The content of cobalt oxide is 0.01 to 0.41 in terms of cobalt atoms.
It is more preferably within the range of parts by weight.

Table 2 shows that among the above samples, the cobalt content of D is 0.04 parts by weight in terms of cobalt atoms, and the nickel content is 0.
．． Green monochromatic brightness of cathode ray tube using 75 ppm phosphor,
Shows dark area brightness and external light reflectance characteristics.

The green monochromatic luminance is the value when the electron beam current is 1.6 μA/ad and the value when the electron beam current is 0.02 μA/cJ.

Table 2 Comparison field R is a cathode ray tube using a phosphor that uses the same host phosphor but does not contain cobalt oxide or nickel on the surface, Comparison field S
is a cathode ray tube using the same host phosphor but containing 10 ppm of cobalt and 0.75 ppm of nickel on the surface.

As is clear from Table 2, the cathode ray tube of the present invention has low dark area brightness, high monochromatic green brightness, and low external light reflectance, showing good characteristics.

(Example 2) Using a ZnS:Cu AQ phosphor in substantially the same manner as in Example 1, a phosphor having a content layer containing cobalt oxide and nickel is fabricated. The content of cobalt oxide is 0.04 parts by weight based on 100 parts by weight of the base material in terms of cobalt atoms. Nickel content 1-7
Eight types of samples with different ppm ranges were manufactured.

A color cathode ray tube is similarly manufactured using these eight types of phosphors.

FIG. 4 is a diagram showing the relationship between dark area brightness and nickel content when this cathode ray tube and the comparative amount R in Example 1 were operated.

From this figure, nickel is 0. If it is less than 1 ppm, the effect of lowering dark area brightness is small. If it exceeds 5 ppm+, the effect of reducing brightness in dark areas reaches a saturation range, and the green monochromatic brightness decreases, which is not preferable. The preferred range is 0.3 to 3 ppm.

FIG. 5 shows J=nickel 0 among the above samples. lppm.

K=nickel 0.75ppm and L=nickel 3ppm
The relationship between the electron beam current density and the relative brightness was measured for three types of cathode ray tubes, and the relative brightness was determined by the comparison amount R.
The brightness of is set to 100. As is clear from FIG. 5, the cathode ray tube of the present invention using a nickel-containing phosphor has a greater decrease in relative brightness in the low current density region, which indicates that there is less light emission due to scattered electrons within the cathode ray tube. It is supported. The relative brightness in the high current density region is sufficiently high.

Figure 6 shows that among the above samples, the nickel content is lPP11.
, 2 ppm, and 3 ppm of phosphors were operated, and the relationship between relative luminance and dark area luminance was determined.

The comparative amount (dashed line) is 10pp of cobalt using the same host phosphor.
This is a curve obtained by similarly determining the relationship between relative luminance and dark area luminance for cathode ray tubes using three types of phosphors containing m and containing 1 ppm, 2 pill, and 3 ppm of nickel.

As is clear from FIG. 6, the cathode ray tube of the present invention exhibits excellent characteristics, with extremely low dark area brightness at the same emission brightness.

(Example 3) ZnS with an average particle size of 8.0μ washed with water and dispersed in a bead mill:
Prepare 500 g of Cu Au, Afi phosphor. Put 2.5Q pure water in a beaker, and add the phosphor while stirring.

Next, a sample to which 1.616 g of CoCQ, .6H20 was added was prepared. znS04.77H2O800 is added, and the circle is maintained at 18 to 8.5 with a 1% NH4OH aqueous solution to adhere a mixed precipitate of cobalt hydroxide and zinc hydroxide to the phosphor. Next, after repeating the process several times with pure water.

Drain the supernatant and add Ni So, 7H201,8
Add 10-"g of the
After firing for 60 minutes at .degree. C. and processing in a conventional manner, a phosphor having a layer containing cobalt oxide and nickel is obtained. The content of nickel in the containing layer is 0.75 ppm, and the content of cobalt oxide is 0.08 parts by weight in terms of cobalt atoms based on 100 parts by weight of the base material.

A color cathode ray tube is manufactured using this phosphor using the usual method.

Table 3 shows the green monochromatic brightness, dark area brightness, and external light reflectance characteristics of this cathode ray tube.

Comparison amount R-1 in Table 3 is a cathode ray tube using a phosphor that uses the same host phosphor but does not contain cobalt oxide and nickel on the surface, and comparison amount S-1 uses the same host phosphor but has 20pp of cobalt on the surface.
This is a cathode ray tube using a phosphor containing 0.75 ppm of nickel.

As is clear from Table 3, the cathode ray tube of the present invention has low dark area brightness, high monochromatic green brightness, and low external light reflectance, showing good characteristics.

In addition to the above, cathode ray tubes using the green-emitting phosphor also showed similar trends.

The cathode ray tube of the present invention was developed for the same purpose as the present invention (Patent Application No. 1988-) (filed on October 21, 1985).
Compared to a cathode ray tube using a phosphor in which a cobalt oxide-containing layer is formed on the surface of the host phosphor, dark area brightness is further improved.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a phosphor according to the present invention, FIG. 2 is a schematic cross-sectional view of a cathode ray tube according to the present invention, and FIG. FIG. 4 is a diagram showing the relationship between the nickel content in the phosphor-containing layer used in the cathode ray tube of the present invention and the dark area brightness of the cathode ray tube, and FIG. 5 is a diagram showing the electron beam current of the cathode ray tube of the present invention. FIG. 6 is a diagram illustrating the relationship between density and relative brightness, and FIG. 6 is a diagram illustrating the relationship between relative brightness and dark area brightness of the cathode ray tube of the present invention. 1...Mother phosphor 2...Containing layer 7...Phosphor layer Fig. 1] Umajirushi (kV) Fig. 3 ・STo −'ρ−20−S% Ki1 吋1 Figure 6

Claims (6)

[Claims] (1) In a cathode ray tube equipped with a panel on which a green-emitting phosphor based on zinc sulfide is adhered, and an electron gun for projecting an electron beam onto the panel, the green-emitting phosphor is attached to the surface of the matrix. A cathode ray tube characterized by having a layer containing cobalt oxide and nickel. (2) The content of cobalt oxide contained in the containing layer is 0.0 parts by weight per 100 parts by weight of the base material in terms of cobalt atoms.
2. The cathode ray tube according to claim 1, wherein the content is within the range of 0.05 to 1.0 parts by weight. (3) The content of cobalt oxide contained in the containing layer is 0.000 parts by weight per 100 parts by weight of the base material when converted into cobalt atoms.
2. The cathode ray tube according to claim 1, wherein the content is within the range of 0.01 to 0.41 parts by weight. (4) The content of nickel contained in the content layer is 0.1 to
The cathode ray tube according to claim 1, characterized in that the concentration is within a range of 5 ppm. (5) The content of nickel contained in the content layer is 0.03
The cathode ray tube according to claim 1, characterized in that the concentration is within the range of 3 ppm to 3 ppm. (6) A patent characterized in that the host phosphor is at least one of a copper and aluminum activated zinc sulfide phosphor, a copper, gold and aluminum activated zinc sulfide phosphor, and a copper and aluminum activated zinc sulfide cadmium phosphor. A cathode ray tube according to claim 1.