JPH0822778A - Projection cathode ray tube - Google Patents

Abstract

(57) [Summary] [Object] To provide a projection type cathode ray tube for a short afterglow green image with an afterglow time of 0.6 ms or less. A mixed phosphor of P46 green light emitting phosphor and another green light emitting phosphor, wherein the mixing ratio of P46 green light emitting phosphor is 2 to 30%, and the other green light emitting phosphor is The body is P53 or P53 (Ga), or another green-emitting phosphor is P53.
A mixed phosphor that meets the condition that it is a mixed phosphor of 53 (Ga) and P1 or that the other green-emitting phosphor is a mixed phosphor of P53 (Ga) and P22. Form a film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection cathode ray tube, and more particularly to a projection cathode ray tube for short afterglow green image.

[0002]

2. Description of the Related Art Generally, a projection type cathode ray tube is arranged at a position separated from a projection screen by a predetermined distance, and a reproduced image displayed on a fluorescent surface formed on the inner surface of the panel of the bulb is enlarged by a lens system for magnifying projection ( In many cases, a so-called projection type image device (projection type television set or video projector) that enlarges and projects on a projection screen via a reflection mirror for optical path reversal for reducing the depth of the device case)
Widely used in.

FIG. 7 is a top view of essential parts of an example of a color projection type image device using a projection type cathode ray tube. In the figure, rPRT
Is a projection cathode ray tube for red images, gPRT is a projection cathode ray tube for green images, and bPRT is a projection cathode ray tube for blue images. On the center line of the green image projection cathode-ray tube gPRT, a projection screen is arranged facing the panel PNL and at a predetermined distance. In addition, rPRT and bPRT are arranged at a predetermined angle (referred to as a concentration angle) on the projection screen with the gPRT in between. Further, the respective magnifying projection lens systems LNS are arranged on the same axis as the central axes of the projection cathode ray tubes rPRT, gPRT, and bPRT facing the front surface side of the panel PNL, and the projection cathode ray tubes rPRT are arranged. , GPRT, and bPRT
The monochromatic images of the respective colors reproduced on the fluorescent surface of the inner surface of the panel PNL of the panel PNL are condensed and enlarged by the respective magnifying projection lens systems LNS and projected on the projection screen, and the three primary color images are superimposed. A color image is obtained.

A projection type image device using such a projection type cathode ray tube has a screen size (especially 40 inches or more) larger than that of a direct view type image device (direct view type television set) which has been generally used at home. Although it was commercialized as one means to see the television image screen on, the performance has improved remarkably in recent years, and the brightness and resolution have become equal to or more than those of the direct view type, so it suddenly increases with the size of the screen. It is becoming widespread in place of the direct view type, which increases in weight.

[0005]

Under the circumstances as described above, recently, there has been an active demand for the purpose of producing virtual reality images for business use. Therefore, there is an urgent need to supply a projection type cathode ray tube for satisfying the necessary specific conditions, particularly a projection type cathode ray tube for a green image having a short afterglow characteristic of 0.6 ms or less.

Generally, the afterglow characteristics of a cathode ray tube are determined by the characteristics of a phosphor that is irradiated with an electron beam to emit light and display an image. Table 1 shows a summary of the practical characteristics of currently known (existing) green-emitting phosphors.

[0007]

[Table 1]

From this table, it can be seen that there are only two types of phosphors having afterglow characteristics of 0.6 ms or less: the P46 phosphor and the P22 phosphor. However, these phosphors have the drawbacks as shown in Table 1 which pose practical problems.
That is, the former P46 phosphor has a problem of luminance, chromaticity, spectral distribution, and luminance deterioration, and the latter P22 phosphor has a problem of luminance saturation (γ) characteristic, spectrum distribution, and luminance deterioration. In particular, the former P46 phosphor has the greatest drawback of luminance, and the latter P22 phosphor has the greatest drawbacks of luminance saturation (γ) characteristic and luminance deterioration.
It has been a cause of impediment to practical use.

The present invention combines (mixes) appropriate phosphors from among these known (existing) green-emitting phosphors, and has afterglow characteristics of 0.6 ms or less, satisfying various practical characteristics. An object of the present invention is to provide a short-afterglow green image projection type cathode ray tube in which a fluorescent film is formed by using a fluorescent substance having a mixing ratio.

[0010]

In order to solve the above problems, in the projection type cathode ray tube of the present invention, (A) a mixed phosphor of a P46 green light emitting phosphor and another green light emitting phosphor is used. Therefore, the mixing ratio of (B) P46 green light emitting phosphor is 2 to 30.
%, And (C) other green-emitting phosphors are P53 or P5.
3 (Ga), or (D) another green-emitting phosphor is P
53 (Ga) and P1 is a mixture, or (E) the other green-emitting phosphor is a mixture of P53 (Ga) and P22. I decided to form.

[0011]

The relationship between the mixing ratio of phosphors and the afterglow value when the phosphors having greatly different afterglow values are mixed is as shown in FIG.
It is not a simple (proportional, linear) relationship (indicated by a solid line in the figure), but the afterglow of the short-afterglow phosphor is dominant, which is more than the mixing ratio of the short-afterglow phosphor. It has a short afterglow (indicated by a broken line in the figure). Therefore, normally, the vertical axis (afterglow axis) is shown in semi-logarithmic coordinates in which the logarithm of the afterglow value is expressed.

In the case of the present invention, the afterglow value of the phosphor that is the basis of the phosphors to be mixed, that is, the P46 phosphor is 160.
Focusing on the point of ns, which is an ultra-short afterglow, and experimentally observing the afterglow value when mixed with a medium afterglow phosphor in ms units, The projection cathode ray tube thus formed was prototyped and the afterglow value was measured and confirmed.

As a P46 fluorescent substance, P46- shown in Table 1 is used.
FIG. 1 shows the trial and measurement results of the afterglow value (vertical axis) with respect to the mixing ratio (horizontal axis) with the P53 (Ga) fluorescent material as the Y2 fluorescent material and the other fluorescent materials. In this figure, the actual measurement results for the prototype real sphere show that the relationship between the mixture ratio of the P46 phosphor and the afterglow value is not linear (indicated by the solid line in the figure) even in the semilogarithmic coordinate. The contribution of the P46 fluorescent substance is significantly effective, and the afterglow is shorter than the linear relationship even when displayed in semilogarithmic coordinates (indicated by a broken line in the figure). As can be seen from this figure, the afterglow value becomes 0.6 ms or less P46-Y2
The mixing ratio of the fluorescent substance is 2% or more.

Next, a phosphor obtained by mixing 93% P53 (Ga) and 7% P1 was used as the other phosphor for the P46-Y2 phosphor, and the afterglow with respect to the mixing ratio (horizontal axis). FIG. 2 shows the results of trial production and actual measurement for the values (vertical axis). Also in this case, it is similar to the above, and it can be seen that the mixing ratio of the P46-Y2 phosphor having an afterglow value of 0.6 ms or less is 5% or more.

Further, as another fluorescent substance, P53 (Ga) is used.
Taking a phosphor in which a (medium afterglow) phosphor and a P22 (short afterglow) phosphor are mixed, the optimum mixing ratio of this mixed phosphor to the P46-Y2 (ultra-short afterglow) phosphor is taken. To decide, first
The relationship of the chromaticity values (CIE coordinates: x, y) with respect to the mixing ratio of the P53 (Ga) phosphor and the P22 phosphor was confirmed by making trials and actual measurements on a real sphere. FIG. 4 shows the results. From this result, the chromaticity value (x =
It was found that the mixing ratio of P22 to P53 (Ga) that gives a chromaticity value close to 0.330, y = 0.575) was 30%. So, this 30% P22 and 70
The relationship of the afterglow value with respect to the mixing ratio of the phosphor mixed with% P53 (Ga) and the P46-Y2 phosphor was confirmed by performing actual spherical trial manufacture and measurement. The result is shown in FIG. This result is also similar to the above, and it can be seen that the mixing ratio of the P46-Y2 phosphor having an afterglow value of 0.6 ms or less is 2% or more.

The above-mentioned examination and the range of the mixing ratio were determined by the afterglow value. However, the other main characteristic is brightness. As shown in Table 1 above, the brightness of the P46-Y2 phosphor is the current phosphor (93% P53 (Ga) + 7% P1).
To 45%. Therefore, as the amount of P46-Y2 phosphor mixed increases, the brightness decreases, so P46-Y2
It was decided to determine the upper limit of the mixing amount of the fluorescent substance by the luminance ratio with respect to the current fluorescent substance. As a reference, the range of the luminance ratio of the mixed phosphor was set to 90% or more of the current phosphor in consideration of the fact that the difference in brightness that can be visually confirmed is within 10%.

From the above viewpoints, FIG. 5 collectively shows the measurement results of the actual sphere prototype for the mixing ratio when the P46 phosphor is mixed with the above-mentioned various phosphors and the luminance ratio with respect to the current phosphor.

Table 2 shows the results in consideration of the above luminance values and the results by the above-mentioned afterglow value.

[0019]

[Table 2]

Based on the above results, the practical optimum range of the mixing ratio of the P46-Y2 phosphor is set to 2 to 30%.

[0021]

EXAMPLES Hereinafter, typical examples of the present invention will be described in detail.

As a first embodiment, P53 is added to the P46 phosphor.
The case where (Ga) fluorescent materials are mixed will be described. Table 2
As described in (1), the optimum range of the mixing ratio of the P46 phosphor is 2 to 25%. Therefore, a projection type cathode ray tube having a fluorescent film formed by a precipitation coating method, which is a usual coating method, was experimentally manufactured by using a phosphor having the following typical mixing ratio.

Fluorescent Material and Mixing Ratio ... P46: 20% P53 (Ga): 80% As a second embodiment, P46 fluorescent material contains 93% P53 (G).
A case where a) and a mixed phosphor (current) of 7% P1 are mixed will be described. As shown in Table 2, the optimum range of the mixing ratio of P46 is 5 to 18%. Therefore, using the phosphors having the following mixing ratios, a projection type cathode ray tube having a fluorescent film formed by the sedimentation coating method was manufactured as in the case of the first embodiment.

Fluorescent substance and mixing ratio ... P46: 18% 93% P53 (Ga) + 7% P1: 82% As a third embodiment, a P46 fluorescent substance and 70% P53 (G
A case of mixing the phosphor in which a) and 30% P22 are mixed will be described. As shown in Table 2, the optimum range of the mixing ratio of P46 is 2 to 30%. Therefore, using a phosphor having the following typical mixing ratio, as in the case of the first embodiment,
A projection type cathode ray tube with a fluorescent film formed by the sedimentation coating method was prototyped.

Fluorescent substance and mixing ratio ... P46: 20% 70% P53 (Ga) + 30% P22: 80% Regarding the projection type cathode ray tube prototyped in each of the above examples, the afterglow value and The luminance ratios (vs. current) are summarized in Table 3.

[0026]

[Table 3]

It was confirmed that each of them satisfied the target value and there was no problem in practical use.

[0028]

As described above, according to the present invention, the condition that the afterglow value is 0.6 ms or less can be completely satisfied, and it is suitable for use in a projection image device for high definition or stereoscopic images. In addition to the result, it is possible to secure the quality which is not a practical problem with respect to the conventional main characteristics such as luminance and chromaticity.

[Brief description of drawings]

FIG. 1 shows the P46-Y2 phosphor shown in Table 1 as a P46 phosphor, the P53 (Ga) phosphor as another phosphor, and the afterglow value (longitudinal axis) with respect to its mixing ratio (horizontal axis). It is a figure which shows the trial manufacture / actual measurement result about (axis).

FIG. 2 shows the P46-Y2 phosphor as another phosphor.
It is a figure which shows the trial manufacture and the measurement result about the afterglow value (vertical axis) with respect to the mixing ratio (horizontal axis | shaft) using the mixed fluorescent substance of 3% P53 (Ga) and 7% P1.

FIG. 3: P46-Y2 phosphor 30% as another phosphor
It is a figure which shows the result of having measured the relationship of the afterglow value with respect to the mixing ratio at the time of mixing the mixed fluorescent substance of P22 and 70% P53 (Ga) by experimentally manufacturing a real sphere.

FIG. 4 shows a chromaticity value with respect to a mixing ratio of a P53 (Ga) phosphor and a P22 phosphor for a real sphere as a prototype, and as a result of actual measurement, a chromaticity value close to that of the working phosphor is obtained. P53
It is a figure which shows that the mixing ratio of P22 with respect to (Ga) is 30%.

FIG. 5: Considering that the difference in brightness that can be visually confirmed is within 10%, when the range of the brightness ratio of the mixed phosphor is set to 90% or more of the current phosphor, it is regarded as P46 phosphor. It is a figure which shows collectively the result of having actually measured the mixing ratio at the time of mixing various fluorescent substances, and the brightness ratio with respect to the present fluorescent substance about the prototype real sphere.

FIG. 6 shows a simple (proportional, proportional relationship between the mixing ratio of phosphors and the afterglow value when phosphors having significantly different afterglow values are mixed.
The relationship is not linear (indicated by the solid line in the figure), and the afterglow of the short-afterglow phosphor becomes dominant, and the afterglow is much shorter than the mixing ratio of the short-afterglow phosphor (Fig. (Indicated by a broken line in the middle).

FIG. 7 is a main part top view of an example of a color projection type image device using a projection type cathode ray tube.

[Explanation of symbols]

rPRT ... red image projection cathode ray tube, gPRT ... green image projection cathode ray tube, bPRT ... blue image projection cathode ray tube, PNL ... panel, LNS ... magnifying projection lens system.

Claims (5)

[Claims] 1. A projection type cathode ray tube characterized in that a fluorescent film is formed by using a mixed phosphor of a P46 green light emitting phosphor and another green light emitting phosphor. 2. The mixing ratio of P46 green-emitting phosphor is 2 to 3.
The projection type cathode ray tube according to claim 1, wherein the projection type cathode ray tube is 0%. 3. Another green-emitting phosphor is P53 or P53.
The projection cathode ray tube according to claim 1, which is (Ga). 4. Another green-emitting phosphor is P53 (Ga) and P.
The projection cathode ray tube according to claim 1, wherein the projection cathode ray tube is 1. 5. Another green-emitting phosphor is P53 (Ga) and P.
22. The projection cathode ray tube according to claim 1, wherein the projection cathode ray tube is 22.