JPS6351480B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a white light emitting phosphor and an electron beam excitation display tube having a phosphor film using the white light emitting phosphor.

Conventionally, silver-activated zinc sulfide phosphor (ZnS:
A mixed phosphor of copper- and aluminum-activated zinc sulfide cadmium phosphor [(Zn, Cd)S:Cu, Al] was used. However, since this mixed phosphor is a mixture of a blue-emitting phosphor and a yellow-emitting phosphor, unlike a single phosphor, color unevenness is likely to occur on the fluorescent surface. To solve this problem, gold, silver and aluminum activated zinc sulfide cadmium phosphor [(Zn, Cd)S: Au, Ag,
Al] was proposed, but the color tone of this phosphor was slightly greenish, and the desired white luminescence could not be obtained. Furthermore, since all of the above white-emitting phosphors contain cadmium (Cd), they pose a pollution problem.

As a result of repeated research to solve these problems, we have developed a product that does not contain Cd, which is a pollutant.
A mixed phosphor consisting of ZnS: Ag, gold- and aluminum-activated zinc sulfide phosphor (ZnS: Au, Al), and europium-activated yttrium oxysulfide phosphor (Y ₂ O ₂ S: Eu) was proposed. (Special Publication No. 52-30158). However, since this white-emitting phosphor is a mixture of three types of phosphors emitting different colors, color unevenness is more likely to occur. recently,
As applications such as viewfinder cathode ray tubes, in which the phosphor surface is enlarged 3 to 5 times, are increasing, phosphors that contain no harmful substances and emit good white light with a single phosphor are becoming increasingly popular. It has become sought after.

The present inventors have conducted various studies in view of the above points, and have discovered that all of the above drawbacks can be solved by a sulfide phosphor activated with a specific amount of a specific activator. The invention has been achieved.

That is, in the white-emitting phosphor of the present invention, the activation amount of gold, silver, manganese, and aluminum is 1% zinc sulfide.
10 ^-5 g to 10 ^-2 and 10 ^-5 g to
10 ^-3 g, 10 ^-5 g to 5×10 ^-2 g and 10 ^-5 g to
Gold, silver, manganese and aluminum activated zinc sulfide phosphors in the 10 ^-3 g range.

Further, the electron beam excitation display tube of the present invention includes at least one electron beam emitting part, and is provided opposite to the electron beam emitting part, and the activation amount of gold, silver, manganese, and aluminum as luminescent substances is zinc sulfide. 10 ^-5 g to 10 ^-2 g and 10 ^-5 g to 10 ^-3 per 1 g, respectively
g, 10 ^-5 g to 5×10 ^-2 g and 10 ^-5 g to 10 ^-3
The main part is a phosphor film containing gold, silver, manganese, and aluminum activated zinc sulfide white light-emitting phosphors in the range of g, and these are vacuum-sealed in a container.

By using the white light-emitting phosphor and electron beam excitation display tube of the present invention, a single phosphor that does not contain pollutants and emits good white light, and an electron beam that emits good color without uneven color. An excitation display tube is obtained.

The present invention will be explained in detail below.

The white light-emitting phosphor of the present invention is manufactured, for example, by the following method. That is, first, Au compounds such as chlorides, Ag compounds such as nitrates, Mn compounds such as carbonates, and Al compounds such as nitrates are added to ZnS raw powder as raw materials for the activators Au, Ag, Mn, and Al. Mix thoroughly using a ball mill, mixer mill, etc. to obtain a phosphor raw material mixture. Here, it goes without saying that each activator compound is added in a stoichiometric manner to provide the desired amount of each activator for the phosphor. Furthermore, a flux commonly used in the production of sulfide phosphors or a small amount of sulfur for oxidation prevention may be added to each of the above-mentioned phosphor raw materials. Next, the obtained phosphor raw material mixture is filled into a heat-resistant container such as a quartz crucible or an alumina crucible and fired.
Firing is performed at a temperature of 800°C to 1030°C in a sulfidic atmosphere such as a hydrogen sulfide atmosphere or a sulfur atmosphere. The firing time varies depending on the filling amount of the phosphor raw material mixture, the firing temperature employed, etc., but generally 30 minutes to 5 hours is appropriate. After firing, wash the resulting fired product with water,
After drying, a ZnS:Au, Ag, Mn, Al phosphor is obtained.

In the present invention, the above-mentioned activator amount is 10 ^-5 g to 10 -2 g of Au and 10 ^-2 g of Ag per 1 g of zinc sulfide which is the base material.
10 ^-5 g to 10 ^-3 g, Mn is 10 ^-5 g to 5×10 ^-2 g
And Al is in the range of 10 ^-5 g to 10 ^-3 g, and white light emission can be obtained within this range. In particular, from the point of view of color purity and brightness, the above activation amount is 5×10 ^-5 g to 3×10 ^-4 g for Au, 5×10 ^-5 g to 2×10 ^-4 g for Ag,
Mn is 1×10 ^-3 g to 2×10 ^-2 g and Al is 1×
More preferably, the amount is in the range of 10 ^-4 g to 5×10 ^-4 g.

FIG. 1 shows the emission spectrum of the phosphor of the present invention. Curve 1 and Curve 2 both represent the phosphor of the present invention, and when the amount of activation of the activator is changed, the emission spectrum changes in this way. When the emission color of the emission spectrum shown in FIG. 1 is written in the (x, y) coordinates of CIE, it becomes as shown in FIG. 2. The area surrounded by curve a in Figure 2 is the white area in Kelly Chart, and the area surrounded by curve b is currently considered the most desirable white area for black and white cathode ray tubes. White emission with a slight blue direction is preferred. Emission spectra 1 and 2 in FIG. 1 correspond to point 1 in FIG. 2, respectively.
and 2. As described above, all of the phosphors of the present invention exhibit good white light emission within the range surrounded by curve a.

Furthermore, since the white-emitting phosphor of the present invention has sufficiently high luminance, it can be used as a phosphor for electron beam excitation display tubes. Furthermore, since the white-emitting phosphor of the present invention does not contain a red-emitting phosphor containing an expensive rare earth element, it is more effective than white-emitting phosphors containing red-emitting phosphors that are currently in practical use. This makes it an inexpensive phosphor.

Next, a cathode ray tube for black and white television, which is an example of an electron beam excitation display tube of the present invention, will be described, which uses the above-described white light-emitting phosphor of the present invention as a fluorescent film.

The structure of the cathode ray tube for black and white television of the present invention is exactly the same as the conventional cathode ray tube for black and white television, except for the fluorescent film, as shown in FIG. That is, the cathode ray tube for black and white television of the present invention has one electron gun 13 in the neck portion 12 of the funnel 11, and a fluorescent film 15 is formed on the entire surface of the face plate 14 facing the electron gun 13. be. Generally, an aluminum vapor-deposited film 16 is provided on the back side of the fluorescent film 15 to prevent charge up during excitation. In the cathode ray tube for black-and-white television constructed in this manner, the phosphor film is made of the white-emitting phosphor of the present invention described above. The fluorescent film is formed by a precipitation coating method which is generally employed as a method for forming a fluorescent film on cathode ray tubes for black and white television. The amount of phosphor in the phosphor film is 2.0 per cm ² in terms of luminance.
A range of ~7.0 mg is appropriate. More preferably 1
It ranges from 2.5 to 6.0 mg per cm ² .

Since the cathode ray tube for black-and-white television of the present invention uses a phosphor film made of a single phosphor, no color unevenness occurs at all.

Incidentally, in the present invention, phosphors of other luminescent colors may be mixed for slight color correction. If the amount is within 10% by weight of the essential components of the phosphor of the present invention, color unevenness will hardly be detected.

Although the cathode ray tube for black-and-white television has been described above, similar effects can be obtained when used in other electron beam excitation display tubes, such as low-speed electron beam excitation fluorescent display tubes.

The present invention will be explained below with reference to Examples.

Example 1 Zinc sulfide (ZnS) 100g Silver nitrate (AgNO ₃ ) 0.032g Chlorauric acid (HAuCl ₄ , 4H ₂ O) 0.029g Aluminum nitrate [Al(NO ₃ ) ₃ , 5H ₂ O] 0.25g Manganese carbonate (MnCO ₃ ) 2g The phosphor raw material was thoroughly mixed using a ball mill, which also served as pulverization, and then placed in a heat-resistant container and fired at 970° C. for 5 hours in a reducing atmosphere. In this way, ZnS: 1.4×10 ^-4 Au, 2×10 ^-4 Ag, 9.56
×10 ^-3 Mn, 2×10 ^-4 Al phosphors were obtained. This phosphor was coated on a clear face plate with a transmittance of 86% by a precipitation coating method to produce a cathode ray tube as shown in FIG. Curve 1 in FIG. 1 shows the emission spectrum when this cathode ray tube was caused to emit light under stimulation conditions of a current density of 1 μA/cm ² and an accelerating voltage of 15 KV. Further, the luminescent color at this time was (x, y) = (0.230, 0.250), indicating good white luminescence as shown at point 1 in FIG. Moreover, this cathode ray tube did not cause color unevenness at all.

Example 2 Zinc sulfide (ZnS) 100g Silver nitrate (AgNO ₃ ) 0.008g Chlorauric acid (HAuCl ₄ , 4H ₂ O) 0.029g Aluminum nitrate [Al(NO ₃ ) ₃ , 5H ₂ O] 0.25g Manganese carbonate (MnCO ₃ ) 4g A phosphor was produced in the same manner as in Example 1 except that the above phosphor raw material was used. ZnS like this:
1.4×10 ^-4 Au, 5×10 ^-5 Ag, 1.9×10 ^-2 Mn, 2×
A 10 ^-4 Al phosphor was obtained. A cathode ray tube was manufactured using this phosphor in the same manner as in Example 1, and the emission spectrum when emitted under the same conditions is shown in curve 2 in FIG. Also, the emission color at this time is (x, y) = (0.270,
0.310), and exhibited good white light emission as shown at point 2 in FIG. Moreover, this cathode ray tube did not cause color unevenness at all.

[Brief explanation of the drawing]

FIG. 1 shows the emission spectrum of the phosphor of the present invention, FIG. 2 shows its CIE (x, y) coordinates, and FIG. 3 is a schematic cross-sectional view of a cathode ray tube for black and white television according to the invention. 11: Funnel, 12: Network part, 13: Electron gun, 14: Face plate, 15: Fluorescent film, 1
6: Aluminum vapor deposited film.

Claims (1)

[Claims] 1. The activation amount of gold, silver, manganese, and aluminum is 10 ^-5 g to 1 g of zinc sulfide, respectively.
10 ^-2 g, 10 ^-5 g to 10 ^-3 g, 10 ^-5 g to 5×10 ^-2
g and gold, silver, in the range of 10 ⁻⁵ g to 10 ⁻³ g;
Manganese and aluminum activated zinc sulfide white emitting phosphor. 2 At least one electron beam emitting part, provided opposite to the electron beam emitting part, and having gold as a luminescent material,
The activation amount of silver, manganese and aluminum is 10 ^-5 g to 10 ^-2 g, respectively, per 1 g of zinc sulfide.
Gold, silver, manganese and aluminum activated zinc sulfide white luminescent fluorescents in the range of 10 ^-5 g to 10 ^-3 g, 10 ^-5 g to 5×10 ^-2 g and 10 ^-5 g to 10 ^-3 g. An electron beam excitation display tube whose main parts include a fluorescent film containing a light substance and which are vacuum-sealed in a container.