JPS61163544A - Projection cathode-ray tube device - Google Patents

Abstract

PURPOSE:To reduce the temperature difference between the center and the periphery of the face plate, and realize a bright picture display, by arranging a clear gel in which a good thermal conductive mesh with blackened surface is placed between the face plate and the lens. CONSTITUTION:In the space of a projection cathode-ray tube 1 composed by the face plate 2, a rubber packing 5, and a lens 4, the closest to the face plate 2 of the projection lenses 3, is filled up a clear gel 6, in which a mesh 8 consisting of a good thermal conductive material is arranged. The surface of the mesh 8 is blackened, and its periphery is connected to a radiating plate. The temperature difference between the center and the periphery of the face plate 2 generated by the drive of the tube 1 is reduced by the mesh 8. Since the temperature difference of the face plate 2 is reduced in this way, the risk of explosion or contraction of the projection cathode-ray tube 1 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a projection tube device used in a television projection device.

2. Description of the Related Art In order to obtain a large-screen television image, a method of projecting the television image onto a relatively small canthus tube and enlarging it and projecting it onto a screen using a projection lens is well known. In this case, since the space between the picture tube and the projection lens is filled with air, light is reflected on the face plate of the picture tube and the lens surface of the projection lens, reducing the amount of light that reaches the screen directly. The screen becomes dark. In addition, the multiple reflected light reaches the screen as unnecessary light, causing bright areas of the image to become whitish and contrast to decrease.
There was a problem with image quality. As a countermeasure to this,
As described in Publication No. 2850, the gate between the face plate and the projection lens is filled with a transparent gel having a refractive index similar to that of the face plate and the projection lens, and the lens surface of the face plate and the projection lens is A method has been proposed to eliminate the reflection of light that occurs in the process and improve the image quality.

An example of the conventional projection tube mentioned above will be described below with reference to the drawings. FIG. 4 is a sectional view of a projection tube device in which a conventional transparent gel is filled between a face plate and a projection lens. A rubber backing 5 is arranged around the periphery of the face plate 2 of the projection tube 1 and the lens 4 closest to the projection tube 1 among the projection lenses 3, and the space formed by these is filled with a transparent gel 6. . By making the gel 6 have a refractive index close to that of glass, it is possible to reduce the reflection of light on the face plate 2 and the lenses 7 of the projection lens 3, increasing the amount of light that reaches the screen, making the image brighter, and Contrast is improved because the amount of unnecessary light that reaches the screen after multiple reflections on each surface is drastically reduced.

Problems to be Solved by the Invention However, in the projection tube device as shown in FIG. 4, the temperature of the filament plate 2 increases because the heat dissipation effect of the gel 6 and the rubber backing 5 at the peripheral portion is poor. However, a temperature difference may occur between the center and peripheral portions of the face plate 2, and the projection tube 1 may implode. Furthermore, even if a large amount of power is input to the projection tube 1 in order to clear a bright image, the projection tube 1 may implode. Furthermore, the lens 4 is also heated through the glue 6, which may distort the lens and deteriorate the image quality, especially in the case of a lens made of resin.

Means for Solving the Problems In order to solve the above problems, the projection tube device of the present invention includes a projection tube, a transparent body disposed in front of the face plate of the projection tube, and the face plate and the transparent body. The structure includes a transparent gel disposed between the transparent gel and a mesh l having a black surface with good thermal conductivity and oriented within the gel.

Function In the above configuration, the face plate is heated by driving the projection tube, but the temperature is generally lower at the center.
At the periphery, the temperature is lower than this, creating a temperature difference. The gel is also affected by this, resulting in a temperature difference between the center and the periphery, but in the present invention, a mesh is placed inside the gel, and good heat transfer occurs through this. As a result, the temperature difference across the faceplate is also significantly reduced. Furthermore, since the surface of the mesh is black, it is possible to prevent diffused reflection of the projection light, and it is possible to obtain an image with high contrast.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 1 is a cross-sectional view of the projection tube device according to the first embodiment of the present invention, in which a transparent space is formed in the space surrounded by the face plate 2 of the projection tube 1, the rubber backing 5, and the lens 4 of the projection lens 3, which is closest to the projection head 1. A mesh 8 as shown in FIG. 2 is disposed inside the gel. This mesh 8 is made of a material with good thermal conductivity such as aluminum, copper, or silver, and its surface is black to prevent diffuse reflection of the projected light and to obtain images with high contrast. . The lens 4 is made of resin.

The operation of the projection tube device configured as described above will be explained. When the projection tube 1 is driven, the ray plate 2 is heated and its temperature rises, but the temperature L R is higher at the center and lower at the periphery, creating a temperature difference. Creates a temperature difference. However, the high heat in the center is transferred to the periphery by the mesh 8, and the temperature difference between the center and periphery of the gel 6 is significantly reduced. This action improves the heat dissipation effect in the central part of the face plate 2, so the temperature decreases, while the temperature in the circular parts increases, so the temperature difference between the central part and the peripheral part of the face plate 2 is reduced considerably. Therefore, the risk of implosion is prevented.

Figure 3 shows the projection tube ￥i in the fJ52 embodiment of the present invention.
, H is a sectional view of FIG. This embodiment has almost the same configuration as the first embodiment, but the peripheral edge of the mesh I8 is connected to the heat sink 9.

The operation of the projection tube device configured as described above will be explained. Projection tube 1 W! Face plate 2 due to movement
The heat generated is transferred to the heat sink 9 through the gel 6 and the mesh 8, and is finally radiated into the air through the heat sink 9. This heat dissipation effect suppresses the temperature rise of the face plate 2, so that a larger amount of power can be input to the projection tube 1 than in the case without the heat dissipation plate 9, and a brighter image can be obtained. Furthermore, since the heat transmitted to the lens 4 is significantly reduced, deterioration in image quality due to distortion of the lens 4 is significantly improved.

Effects of the Invention As described above, according to the present invention, a mesh with good thermal conductivity is placed in the gel, so that face sprays 1 to 1
If the temperature difference between the central part and the circumferential part 3u can be reduced, and a mouth is created to prevent implosion of the projection tube, a bright image with no image quality deterioration can be produced.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a projection tube device according to a first embodiment of the present invention, FIG. 2 is a perspective view of a mesh in the same projection tube device, and FIG. 3 is a cross-sectional view of a projection tube device according to a second embodiment of the present invention. FIG. 4 is a sectional view of a conventional projection tube device. 1... Projection tube, 2... Face plate, 4...
Lens, 6...Gel, 8...Mesh, 9...Radiation plate Fig. 1/-Issuri tube 2--7 Eighth 7-Reto Fig. 2

Claims (1)

[Claims] 1. A projection tube, a transparent body disposed in front of a face plate of the projection tube, a transparent gel disposed between the face plate and the transparent body, and a transparent gel disposed in front of the face plate of the projection tube; A projection tube device comprising: a mesh having a black surface with good thermal conductivity disposed therein; 2. The projection tube device according to claim 1, wherein the mesh has a peripheral portion connected to a heat sink. 3. The projection tube device according to claim 1 or 2, wherein the transparent body is a lens made of resin.