JPS6166784A - Fluorescent screen of color crt - Google Patents

Abstract

PURPOSE:A fluorescent screen that is obtained by adding fluorescent substance of longer afterglowing and green and red emission to a self-activated type zinc sulfide fluorescent substance of short afterglowing blue emission, thus being suitable for use in color displays of high fineness as computer terminal devices. CONSTITUTION:The objective fluorescent screen is obtained by using a mixture of (A) a blue fluorescent substance which is a self-activated zinc sulfide fluorescent substance and has short afterglowing effect with (B) a green and/or red fluorescent substance having 20 or more millisecond afterglowing effect. The content of component A is preferably 30-50wt%, optimally 20-40wt% based on component B. EFFECT:The resultant fluorescent screen has prolonged afterglowing, causes no flickers even when low frame frequency is applied and markedly increases the brightness of blue light.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Field of Application The present invention is directed to color cathode ray tubes (herein referred to as CRT):1. In particular, it is an object of the present invention to provide a fluorescent film suitable for high-definition color display tubes that can be used for observation of computer terminal equipment and the like.

PRIOR ART Current color CRTs have phosphor films with JEDEC (now TEPAC) number P-22, and these phosphors have a short afterglow characteristic of several hundred microseconds.

Color CRTs with this phosphor film do not feel any flicker on the current repetitive screen with a frame frequency of 60 Hz.But what about this?In order to achieve high definition, the dot size of the phosphor The number of dots is increased by reducing the number of dots, and the entire phosphor surface is stimulated by an electron beam with a narrower beam diameter.Furthermore, in order to increase the resolution, the number of horizontal scans is increased. This inevitably increases the horizontal scanning frequency.As a result, the video frequency band increases and the cost of the drive circuit for this increases significantly.In order to avoid this increase in cost, it is necessary to increase the horizontal scanning frequency. By increasing the number of scans but lowering the frame frequency to, for example, 40 Hz, it is better to suppress the increase in horizontal scanning frequency and thereby narrow the video frequency band. If you lower it, the number of repeated screens per second will decrease slightly,
A flicker occurs. this? In order to prevent this, it is necessary to provide the phosphor with afterglow properties. The present invention relates to this afterglow phosphor.

In this specification, the afterglow time is generally expressed as the time when the luminance after the stimulation has completely stopped decreases to 10% of the luminance before stopping.

P-39 (manganese arsenic activated zinc silicate) and P-1 (manganese activated zinc silicate) are known as phosphors with afterglow that emit green light. In addition, for red light emission, P-2
7 (manganese activated zinc phosphate) P-38 (manganese activated 7
Magnesium zinc oxide) is known, and all of these exhibit an afterglow of several tens of milliseconds or longer.

However, no practical blue phosphor with a long afterglow is known.

ZnS:AgC-6 (silver-activated zinc sulfide), which has a short afterglow and is conventionally known as a long-afterglow blue phosphor, has a long afterglow, such as manganese-activated zinc silicate, which has a long afterglow. A method has been developed in which phosphors such as manganese-arsenic activated zinc silicate, manganese-activated zinc phosphate, and manganese-activated zinc magnesium heptadide are appropriately mixed to impart afterglow properties. (Tokuko Showa 57-
(No. 37098) However, phosphors with a long afterglow time have the disadvantage of lower brightness than phosphors with a short afterglow time, and high-resolution cathode ray tubes with sufficient brightness have not been put into practical use. It has not been.

Furthermore, a part of the silver-activated zinc sulfide phosphor is placed in a manganese-activated calcium fluoride phosphor having a high relative luminance, or a phosphor in which this is mixed with a self-activating zinc sulfide phosphor. Technology has also been developed to increase the luminance of long-afterglow blue phosphors. (Japanese Unexamined Patent Publication No. 57-163240) The above manganese-activated calcium heptadide phosphor is.

The self-activating zinc sulfide phosphor used as a blue phosphor in the present invention has poor burning characteristics and current saturation characteristics, and relative luminance is only about 20% lower than that of silver. It is extremely high, twice as much as activated zinc sulfide phosphor. Therefore, if a self-activating zinc sulfide phosphor with a sufficient afterglow time can be put into practical use, a blue phosphor with a long afterglow superior to that of conventional phosphors can be realized.

C6 Purpose of the Invention The object of the present invention is to provide a fluorescent film for a cathode ray tube that has a long afterglow time, does not cause flickering even when used at a low frame frequency, and can significantly increase the luminance of blue light. do.

D. Means for Solving the Conventional Problems The present invention improves the afterglow time by adding one or both of a long afterglow light and a long afterglow edge phosphor to a short afterglow blue phosphor. Increasingly, short afterglow blue phosphors are using self-activating zinc sulfide or self-activating zinc sulfide phosphors with blue filters instead of conventional silver-activated zinc sulfide.

55 Effect The emission color of the self-activated zinc sulfide phosphor is blue, and it is not deep blue like the silver-activated zinc sulfide phosphor, so another blue phosphor is mixed with the self-activated zinc sulfide phosphor. It was thought that it would be impossible to make a long afterglow blue phosphor by mixing it with a red or green long afterglow phosphor without doing so. However, according to experiments by the present inventors, a blue filter brings the luminescent color closer to deep blue, and one type of I-C uses a self-activated zinc sulfide phosphor that does not use a blue filter at all, and a manganese-activated zinc silicate phosphor.

Blue phosphors mixed with long afterglow phosphors such as manganese arsenic-activated zinc silicate, manganese-activated zinc phosphate, and manganese-activated zinc fluoride magnesium are surprisingly similar to red and silver-activated zinc sulfide. Emission color (y value) approximately equal to blue long afterglow phosphor mixed with green long afterglow phosphor.

y value), and also achieved sufficient afterglow time and luminance superior to all conventional products.

This is because the emitted light color of a blue long afterglow phosphor that is a mixture of red and green long afterglow phosphors tends to be closer to white than when the blue phosphor is used alone.

Comparing the emission color of the self-activated zinc sulfide phosphor and the silver-activated zinc sulfide phosphor, the emission color of the silver-activated zinc sulfide phosphor is deep blue, but that of the self-activated zinc sulfide phosphor has a smaller y value than silver-activated zinc sulfide phosphors, more long afterglow red phosphors can be mixed in, and long afterglow red phosphors generally have longer afterglow times. The present invention has been completed by effectively combining the characteristics that the afterglow edge color phosphor is longer than that of the phosphor.

The reason for this will be explained in detail below.

At points A, B, and C in Figure 1, the y values and y values of the silver-activated zinc sulfide phosphor, self-activated zinc sulfide phosphor, and self-activated zinc sulfide phosphor with cobalt blue blue pigment are shown. show. These phosphors are mixed with 0 point (P-27) and E point (P-391 phosphor) to obtain the y value at E point.

Fabricate a y-value phosphor.

A, l:3. For the phosphor at each point C, the y value gradually increases as the amount of manganese-activated zinc phosphate red phosphor is increased, and the amount of manganese-arsenic-activated zinc silicate green phosphor is increased. By doing so, the y value increases.

The phosphor at points B and C (self-activated zinc sulfide) has a smaller y value and larger y value than the phosphor at point A (silver activated zinc sulfide), so the phosphor at points B and C Although the amount of the manganese arsenic activated zinc silicate phosphor mixed is smaller than that of the phosphor at point A,
The emission color can be changed to point E by increasing the amount of the manganese-activated zinc phosphate phosphor mixed. Here, conveniently, manganese-activated zinc phosphate and manganese-activated zinc fluoride magnesium phosphors, which are long afterglow red phosphors, can be replaced by manganese-arsenic-activated zinc silicate, manganese-activated zinc silicate, etc. Since the afterglow time is longer than that of the green phosphor, a large amount of the long afterglow red phosphor can be mixed.

The phosphor of the present invention can achieve sufficiently long afterglow characteristics by reducing the amount of long afterglow phosphor mixed. By the way, the afterglow times of manganese-activated zinc phosphate and manganese-activated zinc fluoride magnesium, which are long afterglow red phosphors, are about 12
The afterglow times of the long afterglow phosphors, manganese arsenide-activated zinc silicate and manganese-activated zinc silicate phosphors, are 80 ms and 20 ms, respectively. It's as short as seconds.

Further advantageously, the relative luminance of self-activated zinc sulfide phosphors is significantly higher than that of silver-activated zinc sulfide phosphors, as shown in Table 1; When added, the luminance can be significantly increased.

(Margins below) Table 1 Furthermore, the self-activated zinc sulfide phosphor whose emission color was moved from the 8 points in Figure 1 to the 0 point using a cobalt blue blue filter has a larger amount of light emitted by the cobalt blue filter to move the emission color to 1 point. The long afterglow edge color phosphors can be mixed and the entire afterglow time can be extended.

Figure 1 shows the color point (G) of manganese-activated calcium fluoride. Even though the relative luminance of this phosphor is somewhat higher than that of the silver-activated zinc sulfide phosphor, the y value is larger than that of a single point, and a considerable amount of the silver-activated zinc sulfide phosphor, which has a lower luminance, is mixed in. It cannot be used as a long afterglow blue phosphor unless the y value is reduced. Therefore, in actual usage conditions, it is extremely difficult to increase the total luminance.

F. Preferred Embodiment Self-activated zinc sulfide blue phosphor, or self-activated zinc sulfide phosphor coated with a blue pigment such as cobalt blue or ultramarine, manganese activated zinc silicate or manganese arsenic activated. By appropriately mixing phosphors such as zinc silicate, manganese-activated zinc phosphate, and manganese-activated zinc magnesium heptadide, the afterglow can be increased to 40~
A total time exceeding 65 milliseconds or 100 milliseconds was obtained.

In order to fully demonstrate how the phosphor of the present invention has superior characteristics compared to conventional long-afterglow blue phosphors, the present inventors investigated three types of conventional examples and three types of the present invention. An actual ttM example was prototyped.

Conventional Example 1 Silver-activated zinc sulfide phosphor, manganese arsenic-activated zinc silicate phosphor (P-39), and manganese-activated phosphorus-ugly zinc phosphor (P-39).
-271 were mixed in an amount of 27% by weight, 30% by weight, and 43% by weight, respectively, to prepare a long afterglow blue phosphor.

Conventional Example 2 Silver-activated zinc sulfide phosphor 33% by weight, manganese-added zinc silicate phosphor (P-1) 32% by weight, manganese-activated zinc fluoride magnesium phosphor (P-38135% by weight) A long afterglow blue phosphor was made by mixing the two.

Conventional Example 3 Silver-activated zinc sulfide phosphor 1) % by weight, manganese-activated calcium fluoride phosphor 30% by weight, manganese-arsenic activated zinc silicate phosphor 9% by weight, manganese-activated zinc phosphate phosphor A long afterglow blue phosphor was prepared by mixing 50% by weight of the phosphor.

Conventional example 4 Self-activated zinc sulfide phosphor (blue emission) ZnS:ZnC2
, manganese arsenic activated zinc silicate phosphor (color recording luminescence) Zn2
Sin4: MnAs and manganese-activated zinc phosphate phosphor (red light emitting) Zn3 (PO4)2: Mn tttP mixed at a ratio of 40% by weight, 12% by weight and 48% by weight is 1/10 The afterglow time was 43 milliseconds and the brightness was 12% higher than a conventional phosphor mixture of the same composition except that self-activated zinc sulfide was replaced with silver-activated zinc sulfide.

Example 2 The same components as in Example 1 were used, except that 1.5% by weight of total cobalt blue pigment and surface-coated self-activated zinc sulfide were used, with 32% by weight, 16% by weight, and 52% by weight, respectively. The color tone of the mixture in the proportions is almost the same as in Example 1, the afterglow time is 65 milliseconds, and the brightness is the same as that of Example 1 using silver-activated zinc sulfide instead of self-activated zinc sulfide. 8% higher than conventional phosphor mixtures.

Example 3 Self-activated zinc sulfide phosphor, manganese-activated zinc silicate phosphor, and manganese-activated zinc fluoride magnesium phosphor at 43%, 23%, and 34% by weight, respectively.
When mixed at a ratio of It was 20% higher than the same price.

G. Effects Table 2 shows how the phosphor of the present invention has superior features compared to conventional phosphors.

To explain this Table 2, the chromaticity values of the conventional phosphor using silver-activated zinc sulfide are X-0,226 and Y-0,2.
The phosphor of the present invention (Example 1 in Table 2) using self-activated zinc sulfide adjusted to almost the same value as 5 has a slightly shorter afterglow time, but the brightness is about 10% higher. did. In addition, when pigment is applied (Example 2)
), the afterglow time was comparable and the brightness was improved by 8%. In addition, in the implementation @3 using P-1 and P-38, the brightness improved by 20% and the afterglow became longer to the extent that it exceeds 100 mm, which is advantageous for frame frequency design. . In this way, a phosphor that produces afterglow in a blue phosphor emits blue-white light, but the color of a phosphor film that combines this light-emitting element with elements that emit green and red light is Reproducibility can be achieved over a fairly wide range as shown by the triangle with vertices D, E, and F in FIG. In addition, in the case where the afterglow time exceeded 30 milliseconds, no light was felt at the frame frequency of 40H2, and the phosphor of the present invention had a sufficient afterglow time. ! IS: The present invention has a relative luminance that is 10 to 20% higher than that of conventional fluorescent films, and has superior characteristics in terms of color point and afterglow time that are comparable to those of conventional products.

[Brief explanation of drawings]

FIG. 1 is a graph showing the color points of phosphors.

Claims (6)

[Claims] (1) In the phosphor film of a color picture tube, at least one of green and red phosphors with an afterglow time of 20 milliseconds or more is added to the blue phosphor with a short afterglow time. In the mixed phosphor film, the blue phosphor with a short afterglow time is a self-activating zinc sulfide phosphor or a self-activating zinc sulfide phosphor having a blue filter, Color C.
RT fluorescent film. (2) The blue phosphor with a short afterglow time is a self-activated zinc sulfide phosphor, which has a short afterglow time of 30 to 50% by weight of the color CRT fluorescent film according to claim (1). (3) The blue phosphor with a short afterglow time is a self-activated zinc sulfide phosphor coated with a blue pigment, which is superior to the entire phosphor including the long afterglow red and long afterglow green phosphors. The color CR according to claim (1) contains 20 to 40% by weight.
Fluorescent film of T. (4) A fluorescent film for a color CRT according to claim (1), in which a blue pigment such as cobalt blue or ultramarine is deposited on the surface of a blue phosphor. (5) The long afterglow red phosphor added to the blue phosphor is either or both of a manganese-activated zinc phosphate phosphor and a manganese-activated zinc-magnesium fluoride phosphor ( A fluorescent film for a color CRT as described in item 1). (6) A patent claim in which the long afterglow edge color phosphor added to the blue phosphor is either or both of a manganese arsenic activated zinc silicate phosphor and a manganese activated zinc silicate phosphor. Range No. 1
A fluorescent film for a color CRT described in item ).