JPH06275197A - Exhaust pipe electric sealing device for cathode-ray tube - Google Patents

Abstract

PURPOSE:To make the whole exhaust pipe electric sealing device compact and attain the shortening of the time required for electric sealing and reduction in power consumption by providing a heater formed by embedding an antioxidant high melting point metallic material in a ceramic material. CONSTITUTION:Since a platinum heater 15 has a maximum temperature of 1000 deg.C or more at operation, it is embedded so that the temperature difference with the ceramic of a heater holding material is minimized as much as possible. Electric sealing is carried out by use of an electric sealing device 10 having such a platinum ceramic heater 15. Thus, the temperature dispersion to an exhaust pipe 5 is minimized, and the exhaust pipe 5 is almost uniformly and efficiently heated. The form of an exhaust pipe 4a after heated and sealed by a platinum wire holding ceramic 11 having a platinum wire 12 satisfactorily has a smaller protruding part into the exhaust pipe inner part than an exhaust pipe 4b after sealed, and the sealing length can be shortened more than in the past. Thus, the device can be made compact, and shortening of electric sealing time and reduction in power consumption can be attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust pipe electric sealing device for a cathode ray tube.

[0002]

2. Description of the Related Art A cathode ray tube (CRT) used as a television receiver or the like has a CR
There is a vacuum evacuation process to make the inside of T a vacuum. This CRT
In the vacuum evacuation process, vacuum degassing is performed using the exhaust pipe (chip pipe) at the end of the neck pipe of the CRT, then the exhaust pipe is electrically sealed, and getter flash is performed in the CRT to about 10 ^-6 Torr. Holding a vacuum.

In the electrical sealing step of the exhaust pipe, as shown in the schematic diagram of the overall electrical sealing configuration in FIG. 4, the panel 2 and the funnel 3 constituting the CRT 1 are connected and sealed, and the obtained C is obtained.
Exhaust pipe (tip pipe) continuous with the neck pipe 4 of the RT envelope
5 is performed by inserting and mounting the electric sealing device 10 and turning on the electric sealing device 10. After that, the degree of vacuum after vacuum evacuation (about 10 ⁻⁶ Torr) is confirmed, and the electric sealing device is turned off to complete the sealing of the exhaust pipe 5 as shown in FIG. 5A.

The exhaust pipe after sealing is indicated by 5b. The exhaust pipe that has been sealed is cut with a file or the like (FIG. 5B), and a stem base (not shown) is inserted into that portion. In the figure, 20 indicates an exhaust main pipe.

As shown in FIG. 6, the conventional electric sealing device used in the electric sealing step has a nichrome wire heater 7 having a diameter of about 1.0 mm on the inner wall of a cylindrical heater fitting heat insulating material 6. Is fitted and the outer circumference is covered with another cover heat insulating material 8.

[0006]

As described above, since the nichrome wire heater is conventionally used as the electric sealing device means, the nichrome wire itself is oxidized by use, leading to early deterioration and deformation of the nichrome wire. The electric sealing shape of the exhaust pipe is also deteriorated. Moreover, since the diameter of the nichrome wire used is as thick as about 1.0 mm, the time for starting up the electrical sealing is lengthened to about 8 minutes, and the current flowing is increased to about 20 A and the power consumption is increased.

In view of the above problems, it is an object of the present invention to provide a lightweight and compact electric sealing device capable of suppressing early change / deterioration, reducing power consumption and improving work efficiency. To do.

[0008]

According to the present invention, there is provided an exhaust pipe electrical sealing apparatus for a cathode ray tube comprising a heater in which an oxidation resistant refractory metal material is embedded in a ceramic material. Will be solved by.

[0009]

According to the present invention, since the heater 15 in which the oxidation resistant refractory metal material, for example, platinum 12 is embedded in the ceramic 11 is used for sealing the exhaust pipe 5 of the cathode ray tube 1, during use, oxidation is caused. Deterioration of the heater material is suppressed, and it is possible to withstand the electric sealing temperature of 800 ° C. Moreover, platinum and glass, which are heater materials, have substantially the same thermal expansion coefficient, and are suitable as a material for processing glass of the exhaust pipe 5.

As a structure for burying platinum in the ceramic material, it is effective that the platinum shape is made flat and a so-called multiple structure of two or three steps is used for the thermal efficiency of the heater and prevention of cracking of the adjacent ceramics. Is. In the present invention, tantalum or the like can be effectively used as the oxidation resistant refractory metal material in addition to platinum.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a schematic view (partially sectional view) showing a state in which an exhaust pipe electrical sealing apparatus for a cathode ray tube according to the present invention is mounted on an exhaust pipe, and FIG. It is a figure which shows especially the heater part in inside, and especially FIG.2 (a) is a cross-sectional view,
FIG. 2B shows an AA enlarged sectional view of FIG. In the figure, the same elements as those shown in FIG. 4 are designated by the same reference numerals. The configuration of the CRT in FIG. 1 has been described with reference to FIG.

In this embodiment, as shown in FIGS. 1 and 2, a platinum ceramic heater having a structure in which a flat platinum wire (ring) 12 is embedded in a flat donut-shaped platinum holding ceramic 11 for improving thermal efficiency, It is configured to be held and covered by the heat insulating material 13 and the cover heat insulating material 14. In particular, the platinum ceramic heater 15 includes a platinum wire 12 having a width of about 0.4 to 0.6 mm and a thickness of about 0.1 mm, and a hemisal (product name: Nichias Co., Ltd.) having a thickness of about 1.0 mm. As a multi-winding structure (double in the figure) in a platinum holding ceramic 11 made of a flat plate donut-shaped ceramic, a structure in which 3 to 4 circular coils of large and small sizes are arranged at equal intervals in one plane and embedded (3 rows 4 as a whole) Heavy). A ceramic such as, for example, Isowool (trade name: manufactured by Isolite Industry Co., Ltd.) is used as the heat insulating material 13, and a ceramic such as Hemisal (trade name) is used as the cover heat insulating material 14 in the vicinity of the periphery of the platinum ceramic heater 15. To use.

Since the platinum ceramic heater 15 has a maximum temperature of 1000 ° C. or higher during operation, it is embedded so that the temperature difference (Δt) between the heater holding material and the ceramic is kept as small as possible. When the electric sealing is performed using the electric sealing device 10 having the platinum ceramic heater 15 as described above, the temperature variation in the exhaust pipe 5 is small, and the exhaust pipe 5 is substantially even and efficient. The shape of the exhaust pipe 4a after being heated and heat-sealed by the platinum wire holding ceramic 11 having the platinum wire 12 as shown in FIG. 3 (a) is shown in FIG. 3 (b) of the conventional example. Exhaust pipe 4 after sealing
It has less protrusions to the inside of the exhaust pipe than the shape of b and is good,
Moreover, the sealing length L1 is about 1/2 of that of the conventional example L2.
I was able to shorten it.

Although platinum is used as the oxidation resistant refractory metal material in the above-mentioned embodiment, tantalum or the like can be effectively used as well.

[0016]

As described above, according to the present invention, the deformation and deterioration of the heater of the electric sealing device can be suppressed, the entire device can be made compact and lightweight from the viewpoint of thermal efficiency, and the electric sealing is required. Time and power consumption can be reduced. Further, since the length of the sealing portion can be shortened, it is possible to contribute to downsizing of the CRT.

[Brief description of drawings]

FIG. 1 is a schematic view (partial cross section) showing a state in which an exhaust pipe electrical sealing device for a cathode ray tube according to the present invention is mounted.

FIG. 2 is a diagram for explaining a heater unit of the electric sealing device shown in FIG.

FIG. 3 is a cross-sectional view showing an exhaust pipe sealed state after electrical sealing of the present invention and a conventional example.

FIG. 4 is a schematic diagram showing the overall configuration of electrical sealing.

FIG. 5 is an explanatory diagram of an exhaust pipe electrical sealing process.

FIG. 6 is a cross-sectional view of a conventional electric sealing device.

[Explanation of symbols]

 1 CRT (Cathode Ray Tube) 2 Panel 3 Funnel 4 Neck Tube 5 Exhaust Pipe (Chip Tube) 6 Heat Insulation Material for Heater Fitting 7 Nichrome Wire Heater 8 Cover Heat Insulation Material 10 Electric Sealing Device 11 Platinum Wire Holding Ceramic 12 Platinum Wire 13 Heat Insulation Material 14 Cover insulation 20 Exhaust main

Claims (3)

[Claims] 1. An exhaust pipe electrical sealing apparatus for a cathode ray tube, comprising a heater in which an oxidation resistant refractory metal material is embedded in a ceramic material. 2. The exhaust pipe electric sealing device for a cathode ray tube according to claim 1, wherein the oxidation resistant refractory metal material is platinum or tantalum. 3. The exhaust pipe electric sealing device for a cathode ray tube according to claim 1, wherein the oxidation-resistant refractory metal material is in the form of a flat plate and is embedded in the ceramic material in a multiple structure.