JPS618836A - Projection cathode-ray tube - Google Patents

Abstract

PURPOSE:To enhance the effect of heat radiation, by placing an RTV rubber of high thermal conductivity as a filler between a heat radiating plate and a metal band wound around the faceplate of a cathode-ray tube. CONSTITUTION:An X-ray shield 7 made of metal is provided around the faceplate 1 of a cathode-ray tube in order to block X-rays. The tube is reinforced by a metal band 6 for preventing the glass of the tube from scattering away at the time of bursting and compression of the tube. An RTV rubber 8 of high thermal conductivity is placed as a filler between a heat radiating plate 4 and one or both of the metal band 6 and the X-ray shield 7 so that the plate 4, the band 6 and the shield 7 are thermally connected to each other. As a result, the band 6 and the shield 7 can function to radiate heat so that the fluorescent faceplate 1 cannot crack even if an electron beam of higher energy than with the radiation of heat only by the heat radiating plate 4 is projected to the faceplate. For that reason, a high-luminance image can be made.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention provides a method in which a translucent front panel is fixed to the front of a fluorescent panel via a frame-shaped heat dissipation plate, and a translucent liquid refrigerant is sealed in between. This relates to a so-called liquid-cooled projection cathode ray tube.

[Background of the invention]

It is a well-known fact that in projection television, the brightness of the projection cathode ray tube must be sufficient to obtain a bright picture on the screen.

Therefore, in order to obtain a high-brightness image, projection-type cathode ray tubes increase the energy of the electron beam that stimulates the fluorescent surface to emit light.The fluorescent surface generates a large amount of heat, but the panel with the fluorescent surface Constructed of glass with relatively low thermal conductivity, the large amount of heat generated on the fluorescent surface is not easily conducted to other parts, resulting in a significant rise in temperature in the center of the panel during continuous operation. . This significant temperature increase causes a decrease in the brightness of the phosphor, whose luminous efficiency is temperature dependent, and also causes the problem that cracks may occur in the panel due to the significant temperature difference between the center and peripheral areas of the panel. Ta.

As a solution to this problem, a liquid-cooled projection type cathode ray tube is developed in which the outer surface of the fluorescent panel is cooled with a refrigerant such as a liquid that causes convection. This method has been proposed in Publication No. 140931 and the like.

FIG. 1 is a sectional view of the essential parts of an example of this type of projection type cathode ray tube. In the figure, a frame-shaped frame having a heat dissipation effect is interposed between the peripheral edge of a fluorescent panel 1 having a fluorescent surface formed on its inner surface and a translucent front glass 2 placed in front of it. A heat dissipation plate 4 is adhesively arranged, and a liquid refrigerant 5 is sealed inside the space surrounded by the heat dissipation plate 4, the fluorescent panel 1, and the front glass 2. The heat from the front surface of 1 is conducted to the heat sink 4,
Since the heat is radiated to the outside, it is possible to prevent a decrease in brightness and the occurrence of cracks. However, with this configuration of the heat sink 4, the heat dissipation effect obtained as a whole is limited because the heat capacity of the heat sink 4 is small. However, it was still insufficient.

[Object of the Invention] Therefore, the present invention was developed in view of these circumstances.
The purpose of this invention is to provide a projection type cathode ray tube in which the cooling effect of the fluorescent surface panel by a refrigerant is further enhanced.

[Summary of the invention]

In order to achieve such an object, the present invention provides a rubber band with good thermal conductivity between the heat sink and the metal band wound around the front panel of the cathode ray tube.
This improves the heat dissipation effect.

[Embodiments of the invention]

Next, embodiments of the present invention will be described in detail using the drawings.

FIG. 2 is a cross-sectional view of essential parts showing an example of a projection type cathode ray tube according to the present invention, and the same parts as in FIG. 1 are given the same reference numerals. In the figure, 6 is a metal reinforcing band wound around the periphery of the panel 1 to prevent implosion, and 7 is a reinforcing band 6.
A metal X-ray shield 8 is wound around the outer circumferential surface of the metal X-ray shield for preventing X-ray leakage. Good RTV rubber, this RTV rubber 8 has an example
,.

For example, DKQ4317A&B manufactured by Dow Corning is suitable.

That is, compared to other cathode ray tubes, projection type cathode ray tubes usually use a higher anode voltage to obtain a high-energy electron beam, so a metal X-ray shield is placed around the panel 1 for the purpose of X-ray shielding. Similar to a normal cathode ray tube, a shield 7 is provided, and a metal band 6 is reinforced to prevent glass from scattering when the cathode ray tube implodes. Therefore, the present invention includes filling RTV rubber 8 with good thermal conductivity between the metal X-ray shield 7 or the reinforcing band 6, or both, and the heat sink 4. Since they are in thermal contact with the X-ray shield 7, it is possible to give the reinforcing band 6 and the X-ray shield T a heat dissipation effect. Even if an electron beam with relatively high energy is emitted, there is no fear of cracks occurring in the fluorescent panel 1, and a high-luminance image can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to enhance the cooling effect of the fluorescent surface panel, so that it is possible to supply a larger amount of electron beam current, and a brighter, higher-intensity image can be obtained. It has an extremely excellent effect of being

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a main part of an example of a conventional projection type cathode ray tube, and FIG. 2 is a cross-sectional view of a main part of an example of a projection type cathode ray tube according to the present invention.

Claims (1)

[Claims] A reinforcing band and an X-ray shield are arranged on the peripheral surface of the fluorescent panel, and a translucent front panel is placed at a predetermined interval in front of the fluorescent panel, and the peripheral edges of both panels are framed. In a liquid-cooled projection type cathode ray tube, the reinforcement band A projection type cathode ray tube, characterized in that RTV rubber having good thermal conductivity is filled between at least one of the wire shields and the heat sink.