JPS58198834A - Cathode-ray tube - Google Patents

Abstract

PURPOSE:To improve luminous efficiency of a phosphor and obtain a picture of high brightness by providing a regulating means of absorbing the influence of a volume change accompanying a temperature change of a coolant having a larger thermal expansion coefficient as compared with that of a solid member, on a spot around a coolant sealing space not interrupting a picture display. CONSTITUTION:A rubber pipe 6 for volume regulation is rich is flexibility and gas-tightness being sealed on one end, while on the other end the inside of a through hole prepared in a metal structure 1 and the outside of the pipe are stuck and sealed together and the pipe inside is communicated with the open air. Thereby, even in the case of continuous use, wherein the temperature of a phosphor screen pannel 2 rises, the pressure rise of a coolant is very little while being able to prevent any crack of a transparent panel 3, the coolant leakage from the adhesion surface by means of adhesives 4 as well as to obtain a picture of high brightness with no drop of the phosphor luminous efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cathode ray tube suitable for high-brightness tubes with a large amount of heat generated in the fluorescent surface, particularly projection tubes.

High-brightness cathode ray tubes used in projection television equipment and the like increase the energy of the electron beam that stimulates the fluorescent surface to emit light in order to obtain high-brightness images.

The amount of heat generated on the fluorescent surface is large. On the other hand, the thermal conductivity of the panel glass coated with the phosphor is relatively low, and the heat generated from multiple sources in the fluorescent direction is not sufficiently conducted to other parts of the cathode ray tube2.Therefore, during continuous operation, The temperature in the center of the panel increases significantly. This significant temperature increase leads to a decrease in the luminous efficiency of the phosphor, and sometimes causes the panel to crank due to the significant temperature difference between the center and the periphery of the panel.

To address this problem, cathode ray tubes have been proposed in which the outer surface of the fluorescent panel is cooled with a transparent coolant, such as a liquid that causes convection.

Figure 1 shows an example of a cathode ray tube in which a fluorescent panel is cooled with a conventional liquid refrigerant. In the figure, 1 is a metal disease, 2 is a fluorescent panel, 3 is a transparent panel, and 4 is an adhesive. %5 is a refrigerant such as an ethylene glycol solution. In this conventional example, the heat generated on the inner surface of the panel 2 is first transferred to the coolant 5, and then further transferred to the metal body 1 by convection, and is radiated to the outside air from the surface thereof. In this way, the temperature rise in the center of the panel 2 was reduced, the decrease in brightness of the fluorescent surface was also reduced, and the effect of preventing panel cracks was also observed. However, the coefficient of thermal expansion of the liquid refrigerant is much larger than that of the solid members that form the refrigerant-filled space, so in the conventional tubes described above, the temperature rise of the fluorescent surface and the accompanying temperature rise of the refrigerant causes the pressure of the refrigerant to rise. significantly increased and cracked a relatively thin transparent panel.

Problems such as refrigerant leaking from the adhesive surface have arisen.

The object of the present invention is to avoid the above-mentioned problems.

An object of the present invention is to provide a high-brightness cathode ray tube whose fluorescent surface is cooled by a liquid coolant.

In order to achieve the above object, the present invention has been made.

It was decided to provide a volume adjustment means to absorb the effect of volume change due to temperature change of the refrigerant, which has a much larger coefficient of thermal expansion than that of the solid member, at a location on the periphery of the refrigerant enclosure space that does not interfere with image display.

FIG. 2 is a plan view of essential parts of an embodiment of the present invention, in which 6 is a rubber pipe for volume adjustment, and other symbols are the same as in FIG. 1. This rubber vibro is highly elastic and airtight, and one end is sealed, and the other end is adhesively sealed between the inside of the through hole provided in the metal structure 1 and the outside surface of the pipe, so that the inside of the pipe communicates with the outside air. In this example, even during continuous use when the temperature of the fluorescent panel 2 increased, the increase in the pressure of the refrigerant was extremely small, and no cracks in the transparent panel 3 or leakage of refrigerant from the surface bonded by the adhesive 4 occurred.

FIG. 3 is a sectional view of a volume adjuster 7 used in another embodiment of the present invention, in which the outer side 7a is made of an iron-nickel alloy and has a low coefficient of expansion, and the inner side 7b is made of stainless steel or the like and has a high coefficient of expansion. As the temperature rises, the cross-sectional shape changes from a circle to a flattened oval, and the area decreases.

Good results were also obtained in Examples using this volume regulator 7.

Although not shown, the desired effect was similarly obtained when a pipe made of a thin metal plate and having a bellows function, the inside of which was communicated with the outside air, was used as the volume adjustment means.

As explained above, according to the present invention, excessive temperature rise of the fluorescent panel is prevented without causing problems such as cranking of the transparent panel or refrigerant leakage, and no decrease in luminous efficiency of the fluorescent material is observed. , a high-brightness image can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of a conventional cathode ray tube in which a fluorescent panel is cooled with a liquid refrigerant, Fig. 2 is a plan view of one embodiment of the present invention, and Fig. 3 is a diagram showing another embodiment. It is a sectional view of the volume adjuster used. DESCRIPTION OF SYMBOLS 1... Metal structure, 2... Fluorescent panel, 3... Transparent panel, 4... Adhesive, 5... Liquid refrigerant, 6...
・Rubber pipe for volume adjustment, 7...Volume adjuster. Agent Patent Attorney Usui 1) Toshiyuki - Figure 1 Figure 2

Claims (1)

[Claims] In a cathode ray tube in which a transparent panel is placed a predetermined distance in front of a fluorescent panel and a flat box-shaped space is sealed and a transparent liquid refrigerant is sealed inside, a space is placed on the periphery of this refrigerant-filled space at a location that does not interfere with image display. , a cathode ray tube characterized in that the space is provided with volume adjustment means for absorbing the effect of volume change accompanying temperature change of a refrigerant having a much larger coefficient of thermal expansion than that of the solid member forming the space.