JPH0421292A - Color cathode ray tube of beam index system - Google Patents

Abstract

PURPOSE:To enter a uniformized light into a light receiving electrode of a photomultiplier and to obtain an excellent picture by providing a diffusion means diffusing the light to an optical path where the light radiating from an index fluorescent body of a color cathode ray tube is made incident on a light receiving electrode of a photomultiplier of side-on type through an index light detection window. CONSTITUTION:An index light Op radiating from an index phosphor 12 of a color cathode ray tube 10 through the scanning of an electron beam onto the index phosphor 12 transmits through an index light detection window 13 and reaches a diffusion plate 16. The index light Op made incident at a comparatively wide angle is diffused to the diffusion plate 16. Then an index light Opa being a part of the diffused lights is made incident on a reflection type photoelectric face 20b of a photomultiplier 20 through an optical filter 18. The index light Opa formed therein is made incident on the reflection type photoelectric face 20b of the photomultiplier 20 through the optical filter 18 effectively and diffused comparatively uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a beam index type color cathode ray tube device suitable for a television receiver.

[Summary of the invention]

The present invention relates to a beam index type color cathode ray tube device suitable for a television receiver, in which light generated from an index phosphor of a beam index type color cathode ray tube passes through an index light detection window to a side-on type photomultiplier tube. By providing a diffusion means for diffusing the light in the optical path when the light is incident on the light receiving electrode,
It is possible to obtain an index signal having a relatively uniform level for scanning the entire screen.

[Conventional technology]

Conventionally, as an example in which a beam index type color cathode ray tube is employed, a color television display device described in, for example, Japanese Unexamined Patent Publication No. 2-53392 has been proposed.

As shown in Figure 3, a beam index type color cathode ray tube has a color cathode ray tube (2) on which three primary color striped phosphors are formed, and a striped index phosphor (21) is further provided within the screen. ing.

The light (hereinafter referred to as index light) generated when the electron beam scans the index phosphor (2a) is transmitted to the transparent index light detection window (3) which is part of the color cathode ray tube (2). A side-on type photomultiplier tube (PSM, T) (5) is passed through an optical filter (4) connected to this index photodetection window (3).
is incident on the Here, a side-on type photomultiplier tube (5
) is used, the length of the photomultiplier tube (5) is arranged along the index light detection window (3), so the entire device is miniaturized.

Then, an index signal SO based on the index light 01 received by the photomultiplier tube (5) is obtained, and after this,
A color video screen is obtained by controlling the three primary color signals based on the index signal SO.

[Problem to be solved by the invention]

However, in the beam index type color cathode ray tube device described above, the photomultiplier tube (5) has an extremely narrow incident angle at which an index signal SO of a predetermined level can be obtained. That is, it is known that sensitivity is non-uniform depending on the position of incident light on the light receiving surface. For this reason,
The index signal S○ obtained by receiving the index light generated when the electron beam scans the index phosphor (2a) of the screen for one horizontal period (IH) increases in level toward the center as shown in Figure 4. . For this reason, it is impossible to reduce the bias current related to the black level for generating the index signal So, and there is a drawback that it is difficult to obtain a video screen with good image quality.

The present invention has been made in view of the above-mentioned problems, and provides an index signal with a relatively uniform level for scanning the entire screen.
It is an object of the present invention to provide a color cathode ray tube device using a beam index method, which can result in a color video screen with good image quality.

[Means to solve the problem]

For example, as shown in the beam index color cathode ray tube device shown in FIGS.
The light generated from the index phosphor (12) of 10) passes through the index light detection window (13) and is received by the side-on type photomultiplier tube (20). (20b) Diffusion means (
16) is provided.

[Effect]

According to the beam index type color cathode ray tube device of the present invention, light generated from the index phosphor is diffused by the diffusion means and input to the photomultiplier tube. In this case, the diffused light effectively reaches the light receiving electrode of the side-on type photomultiplier tube, and an index signal with a relatively uniform level is obtained.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a color cathode ray tube device using a beam index method according to the present invention will be described in detail below with reference to the drawings.

In FIG. 1, (10) indicates a beam index type color cathode ray tube. On the screen of this color cathode ray tube (10), phosphor stripes of three primary colors (not shown) are formed at predetermined intervals, and on the electron gun side (not shown), striped index phosphor (12) is provided at predetermined intervals. It is formed at intervals of . For example, index phosphor (12) stripes and stripes of phosphors of the three primary colors R and GSB are repeatedly provided.

Generally, the color cathode ray tube (10) is provided with an index light detection window (13) which is a transparent glass part through which the index light Op generated by scanning the index phosphor (12) with an electron beam passes. There is.

This index light detection window (13) is
5) is the part that is not coated. This index light detection window (13) is provided with a diffusion plate (16) such as a ground glass plate for covering the index light detection window (13) and diffusing the index light ○p. In this case, the ground glass plate has an index light Op on its surface.
is diffusely reflected, and a part of it passes through the transparent glass part, and multiple index lights ○p are incident here.
The index light Opa is derived from the diffused index light Opa. Furthermore, an optical filter (which is laminated on the diffuser plate (16) to allow only the index light Opa to pass through) is also provided.
18), in which unnecessary three primary color (R, G, B) lights etc. which are simultaneously incident from the diffuser plate (16) are removed. This optical filter (18) has a wavelength (λ) of three primary color lights, for example, 430nm, 550nn+60nm, etc.
For example, if the wavelength is 4001 m, the wavelength is lower than 0 nm.
The index light Opa is passed through as a peak.

Furthermore, a side-on type photomultiplier tube (P,
M, T) (20) is provided, and a transparent glass (20a) forming the exterior body of this photomultiplier tube (20) is provided.
Index light Opa passes through the reflective photocathode (cathode)
(20b). Here, photoelectrons Oe obtained by reflecting the index light ○pa are guided to an electron multiplier by a well-known focusing electrode, doubled by the secondary electron emission effect, and collected at the anode. The anode then outputs the photoelectrically converted index signal Si. Thereafter, the known three primary color signals are controlled based on the level of the obtained index signal S1.

Next, the operation in the above configuration will be explained.

In the color cathode ray tube (10), the index phosphor (12
) The index light ○p generated by scanning the electron beam
passes through the index light detection window (13) and the diffuser plate (
1 day). Here, the index light Oρ incident on the diffuser plate (16) at a relatively wide angle is diffused, and
A part of the diffused index light Opa passes through an optical filter (18) and is incident on a reflective photocathode (20b) of a photomultiplier tube (20).

In this way, for example, if it is not diffused, the diffuser plate (
Since the index light Op that is difficult to reach the optical filter (18) is diffused because it is incident on the optical filter (16) at a relatively wide angle, the index light Op formed here is photoelectron multiplied through the optical filter (18). pipe (20)
The light is effectively incident on the reflective photocathode (20b) and is relatively uniform due to diffusion. This eliminates the disadvantage of using a side-on type photomultiplier tube (20) in which the sensitivity is non-uniform depending on the position of the incident light (index light Op).

In this way, since the index light ρa is relatively uniformly incident on the reflective photocathode (20b), the index signal obtained from the index light Op generated by IH scanning of the index phosphor (12) by the electron beam is S1
As shown in FIG. 2, the level is made constant. Therefore, in order to generate the index signal Si,
The bias current (black level) is reduced, the dynamic range of the color cathode ray tube (10) can be expanded, and a video screen with good image quality can be obtained.

In addition, in the above embodiment, an optical filter is provided on the diffuser plate (16).
(18) are stacked and arranged, and further photomultiplier tubes (20
), but it is not limited to this. For example, the diffuser plate (16) and the optical filter (18) may be arranged with their positions reversed. Also, optical filter (18)
In addition, the surface of this optical filter (18) is formed into a ground glass shape, and the index light ○
p may be diffused. Furthermore, the index light detection window (14) of the color cathode ray tube (10) is formed into ground glass, or the transparent glass (20) of the photomultiplier tube (20) is formed into a ground glass shape.
The part through which the index light ○p passes through in a) may be formed into a ground glass shape, and the index light Oρ may be diffused there.Also, it is also within the scope of the present invention to combine the parts to generate diffusion and obtain the same effect as described above. included.

It is clear that the present invention is not limited to the above-described embodiments, and that various changes can be made without departing from the gist of the present invention.

〔Effect of the invention〕

As can be understood from the above discussion, according to the beam index type color cathode ray tube lid of the present invention, in the optical path when incident on the light receiving electrode of a side-on type photomultiplier tube,
A diffusing means is provided to diffuse the light, and the uniform light is incident on the light-receiving electrode of the photomultiplier tube, so an index signal of a relatively uniform level can be obtained for scanning the entire screen. As a result, the bias current of the frame for generating the index signal can be reduced, and as a result, there is an advantage that a video screen with good image quality can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the configuration of an embodiment of the beam index type color cathode ray tube lid of the present invention, FIG. 2 is a waveform diagram of an index signal according to the configuration shown in FIG. 1, and FIG.
The figure is a sectional view showing the configuration of a beam index type color cathode ray tube according to the prior art, and FIG. 4 is a waveform diagram of an index signal according to the conventional technology configuration shown in FIG. (10) is a color cathode ray tube, (12) is an index phosphor, (13> is an index light detection window, (16) is a diffuser plate, (1B) is an optical filter, (20) is a photomultiplier tube, (20a) ) is a transparent glass, (20kl) is a reflective photocathode, Op is an index light, and Si is an index signal.

Claims (1)

[Claims] Diffusion means for diffusing the light generated from the index phosphor of the beam index type color cathode ray tube into the optical path when the light is incident on the light receiving electrode of the side-on type photomultiplier tube through the index light detection window. A beam index type color cathode ray tube device, characterized in that it is provided with a beam index type color cathode ray tube device.