JPS6174247A - Color cathode-ray tube - Google Patents

Abstract

PURPOSE:To reduce the roughness of the fluorescent screen by doubling the pattern density color phosphors on the display screen by installing a diffraction grating in such a position as to cause diffracted light from one of the color phosphors to be emitted from between the other two color phosphors. CONSTITUTION:The fluorescent screen 1 of a color cathode-ray tube 2 consists of red, green and blue phosphor stripes R, G and B arranged parallel to each other. A diffraction grating 3 is installed in front of the color cathode-ray tube 2 and is at a distance (b) from the fluorescent screen 1 of the color cathode-ray tube 2. Primary diffraction light L1 from one of the red, the green and the blue phosphors is emitted from between the other color phosphors. Accordingly, the pattern density of the phosphor stripes R, G and B is doubled and the roughness of the fluorescent screen is reduced.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a color cathode ray tube device comprising a color cathode ray tube having a phosphor screen composed of red, green, and blue color phosphors arranged in parallel periodically. Regarding.

[Conventional technology]

A color cathode ray tube is known in which a phosphor screen is constructed by aligning red, green, and blue color phosphor stripes R, G, and B. However, in recent years, especially as screens have become larger, the striped pattern of the color phosphor stripes has become visible on the screen, and the roughness of the grain (texture) of the color phosphor stripes has become noticeable.

Therefore, the present applicant first applied for patent application No. 102,745/1986.
A device for arranging microprisms at a predetermined pitch on the front surface of a color cathode ray tube or a patent application No. 1988/1989.
In this issue, we proposed a device in which a transparent birefringent plate is placed in front of a color cathode ray tube. According to these devices, the roughness of the grain of the colored phosphor stripes can be effectively reduced.

[Problem that the invention seeks to solve]

However, microprisms tend to cause moiré, and transparent birefringent plates have problems in that they are expensive to manufacture.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides a color cathode ray tube having a phosphor screen in which red, green, and blue color phosphors are periodically arranged in parallel, for example, the phosphor screen has color phosphor stripes R.
, G, and B on the front of the color cathode ray tube (2).
The diffraction grating (3) is arranged so that the diffracted light from one of the color phosphors is emitted from between the other two color phosphors.

[Effect]

The diffracted light from one of the color phosphors by the diffraction grating (3) is emitted from between the other two color phosphors, and becomes the diffraction grating (5).
When observing from the front of 3), the color phosphor pattern density is doubled and the roughness of the wood grain is reduced.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In this example, as shown in FIG. 1, the front surface of a color cathode ray tube (2) has red, green, and blue color phosphor stripes R, G, and B arranged in sequence to form a phosphor screen (1). A diffraction grating (3) is arranged on.

The diffraction grating (3) is formed in a checkered pattern on a glass plate (4) by, for example, photolithography, as shown in FIGS. 2 and 3, for example. In this case, the pitch of the diffraction grating (3) is lx in the horizontal direction and ly in the vertical direction so that the areas of the black part (3A) and the transparent part (3B) are equal.

For example, if the color cathode ray tube (2) is a 2-inch tube, the diffraction grating (3) has a horizontal length of 50 w and a vertical length of 40 m, and 1x = 40μ, 1y = 1
00P? It is considered FL, and has a black part (3A) and a transparent part (3B).
There are 1250 pairs in the horizontal direction and 400 pairs in the vertical direction.

Further, this diffraction grating (3) is arranged at a predetermined interval from the phosphor screen (11) of the color cathode ray tube (2), and in this case, the first-order diffracted light L1 from one of the color phosphors is It appears to be emitted from between two colored phosphors.

Here, since the green light of the green phosphor G has the highest visibility, the spacing is determined with attention paid to the green light. The wavelength λ of this green light is 0.56 μm, as shown in FIG. Since the horizontal pitch of the grating (3) is lx, the deviation angle θ is λ10=−·····(1) lx. The first-order diffracted light L1 of this green light is red (
In order to make it appear as if the light was emitted from between the R) phosphor and the blue (B) phosphor, 10=5...
(2) must be satisfied. Therefore, (11 and (2
), the interval is b=lx-x y (3)
It is determined that Here, if the color cathode ray tube (2) is a 2-inch tube, for example, lx = 40p-1x = 0.10
5 m.For simplicity, the above formula (3) was calculated assuming that the refractive index ng of the face plate (5) and the glass plate (4) and the refractive index nQ of the air are equal to 1, but in reality, Differences in refractive index are also taken into account.

This example is configured as described above, and the diffraction grating (3) allows
The diffracted light L1 from one of the color phosphors appears to be emitted from between the other two color phosphors, and is observed by the observer (6) in front of the diffraction grating (3) as shown in Figure 1. When, R%G,
The pattern density of the B color phosphor stripes is doubled,
The roughness of the grain on the phosphor screen is reduced.

According to this example, a checkered diffraction grating (3) is provided on the front surface of the color cathode ray tube (2), so there is no concern that moiré will occur. Moreover, this diffraction grating (3) has the above-mentioned advantages and can be easily manufactured by, for example, photolithography, and the manufacturing cost can be kept low. Furthermore, since this diffraction grating (3) functions as a neutral density filter that prevents external light from entering, there is an advantage that it can be observed well even outdoors.

In the above embodiment, the diffraction grating (3) has a checkered pattern, but it may have a striped pattern. Even in this case, since the pitch of the diffraction grating is much finer than the pitch of the color phosphor stripes R, G, and B, there is no fear of moiré.

Further, the above-mentioned embodiment uses color phosphor stripes R and G.

Although the phosphor screen has been described in which B is arranged in parallel, the present invention can be similarly applied to a phosphor screen in which phosphors of each color are periodically arranged in parallel.

〔Effect of the invention〕

According to the present invention described above, a diffraction grating is provided on the front surface of a color cathode ray tube, and there is no need to worry about moiré.
Further, this diffraction grating can be easily manufactured by, for example, photolithography, and the manufacturing cost can be kept low. Furthermore, this diffraction grating has the advantage of functioning as a neutral density filter.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the present invention, FIGS. 2 and 3 are views showing a diffraction grating, and FIG. 4 is a diagram for explaining one embodiment. (1) is a fluorescent screen, (2) is a color cathode ray tube, and (3) is a diffraction grating. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. On the front surface of a color cathode ray tube having a phosphor screen composed of red, green, and blue color phosphors arranged in parallel periodically, the diffracted light from one of the color phosphors is A color cathode ray tube device characterized in that a diffraction grating is arranged so that the light is emitted from between two other color phosphors. 2. The color cathode ray tube device according to claim 1, wherein the diffraction grating is striped or checkered.