JPH021797Y2 - - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to a cathode ray tube, and more particularly to a liquid-cooled cathode ray tube, such as a projection cathode ray tube, which produces high-intensity images using an electron beam with a large current density.

B. Prior art An example of a conventional liquid-cooled cathode ray tube is shown in Figures 1 and 2.
Let's explain from the diagram. In the figure, 1 is a bulb, 2 is a face portion of the bulb 1, 3 is a fluorescent film formed on the inner surface of the face portion 2, 4 is a metal back layer laminated on the fluorescent film 3, and 5 is a metal back layer formed on the fluorescent film 3. Excellent thermal conductivity,
The radiator is an annular radiator made of metal such as aluminum, and has an annular flange 5b extending inward from one end of a cylindrical portion 5a, as shown in FIG.
6 is a light-transmissive front panel made of glass or the like; 7, 7 is the above-mentioned bulb 1 and radiator 5, and radiator 5;
For example, a silicone-based adhesive is used to airtightly seal the front panel 6 and the front panel 6 through spacers 8, 8, respectively.
A cooling liquid 9 is filled and sealed in a space formed between the valve 1 and the front panel 6. Injection of the coolant 9 is performed, for example, by inserting a syringe needle (not shown) through the adhesive 7, and sealing it by closing the injection hole (not shown) at the injection needle mark after filling. will be done. Further, the coolant 9 is suitably an aqueous solution of ethylene glycol known as antifreeze.

In the liquid-cooled cathode ray tube, heat generated by supplying a large amount of electron beams to the phosphor film 3 to obtain high brightness is transferred to the radiator 5 in contact with the coolant 9 through convection of the coolant 9. The face part 2 is cooled by dissipating heat to the outside, preventing a decrease in the luminous efficiency of the phosphor film 3 due to temperature rise, preventing cracks due to thermal distortion of the bulb, and stably obtaining a high-brightness image. There is.

However, when the cathode ray tube is used continuously for a long period of time, the temperature of the coolant 9 increases and its volume expands, causing damage to the valve 1 or front panel 6 due to the increase in internal pressure, and the sealing by the adhesive 7 being damaged, causing the liquid to leak. There was a problem with leaks.

C. Purpose of the invention In view of the above-mentioned problems caused by thermal expansion of the coolant in liquid-cooled cathode ray tubes, the object of the invention is to provide a cathode ray tube that solves these problems.

D. Structure of the invention In the present invention, a front panel is airtightly disposed in front of a valve via an annular radiator, and a space surrounded by the valve, the radiator, and the front is filled with cooling liquid, and the outer peripheral surface of the radiator is sealed. The present invention is characterized in that a groove closed by a stop plate is formed, and the groove and the inner circumferential surface of the radiator are communicated through a communication hole.

Air remains in the groove of the cathode ray tube, and the closed space is filled with cooling liquid.

As a result, the volume change due to the temperature change of the coolant is absorbed by the volume change of the air space in the groove, suppressing an increase in the internal pressure of the coolant, etc., and solving the above-mentioned conventional problems without difficulty. Also, since there are no bubbles on the screen, they do not damage the image.

E. Example An example of the present invention will be described below with reference to FIGS. 3 to 5. In the figure, the same reference numerals as in FIG. 1 indicate the same parts, and details thereof will be omitted. The only difference from the device shown in FIG.
a and a flange portion 10b that is bonded to the front periphery of the face portion 2. The upper wall of the cylindrical portion 10a is thickened to form a groove 11 on the outer circumferential surface, and the bottom surface of the groove 11 and the flange portion are thickened. A narrow communication hole 12 is formed between the upper inner circumferential surface of 10b. The concave groove 11 is used for closing with a sealing plate 13 hermetically sealed and fixed to the upper opening surface thereof.

A coolant 9 is injected into a space surrounded by the front surface of the valve 1, the radiator 10, and the front panel 6. The amount of cooling liquid 9 is set to such an extent that an air space m is created in the groove 11 at room temperature when the valve 1 is placed in its normal position. The cooling liquid 9 may be injected using a syringe needle as in the conventional case, but the sealing plate 13
Alternatively, the liquid may be removed and injected from the groove 11 into the communication hole 12 and into the sealed space in front of the valve, and finally the sealing plate 13 is sealed.

According to the above embodiment, when the coolant 9 undergoes thermal expansion during operation of the cathode ray tube, the expansion is absorbed by the volumetric contraction of the sealed air space m within the groove 11. Therefore, an increase in the internal pressure of the coolant 9 is significantly suppressed, and troubles such as damage to the front panel 6 and leakage of the coolant are eliminated. In particular, if the sealing plate 13 is made of a flexible material, when the cooling liquid 9 thermally expands, it deforms outward as the internal pressure increases, as shown by the chain line in FIG. It is.

A specific example will be described. When a mixture of ethylene glycol and water (at room temperature) of about 24 cc is used as the coolant 9, the volume increase due to thermal expansion is about 1.5 cc at most. Therefore, the volume of the air space m at room temperature is
It has been confirmed that the above effect can be sufficiently exhibited by providing approximately 2.5 to 3 c.c., which is larger than 1.5 cc.

F. Effects of the Invention As explained above, according to the present invention, changes in the internal pressure of the coolant sealed in the front of the valve are absorbed by the space within the groove of the radiator. This prevents liquid leakage due to damage, making it possible to use liquid-cooled cathode ray tubes for long periods of time, extending their service life, and improving reliability. Also, since the bubbles are located outside the screen, they do not affect the image.

[Brief explanation of the drawing]

Fig. 1 is a partial side sectional view showing an example of a liquid-cooled cathode ray tube that is the premise of the present invention, Fig. 2 is a perspective view of the radiator in Fig. 1, and Fig. 3 is a portion showing an embodiment of the present invention. 4 is an exploded perspective view of the radiator and sealing plate in FIG. 3, and FIG. 5 is an enlarged view of the main parts of FIG. 4. 1... Valve, 6... Front panel, 9... Coolant, 10... Radiator, 11... Concave groove, 12...
...Communication hole, 13...Sealing plate.

Claims (1)

[Scope of utility model registration request] A front panel is airtightly arranged in front of the light emitting surface of the bulb via an annular radiator, and a space surrounded by the bulb, radiator, and front panel is filled with cooling liquid, and the outer peripheral surface of the radiator is closed by a sealing plate. What is claimed is: 1. A liquid-cooled cathode ray tube characterized in that a concave groove is formed, and the concave groove and the inner circumferential surface of a radiator are communicated through a communication hole.