JPH0778558A - Shield wire heating method and high frequency heating device of electron gun for cathode-ray tube - Google Patents

Abstract

PURPOSE:To restrict heating of an unnecessary part to the minimum by heating a shield wire, setting the shorter axis side of a noncircular high frequency coil in the direction of the shield wire. CONSTITUTION:A sheild wire 3 surrounds a bead glass 7 holding an electrode 6. A high frequency coil 4 is formed of a copper pipe or the like in a noncircular form such as an ellipse, and a diameter of a longer axis part 9 is set to be twice or more a diameter of a shorter axis part 8. This shorter axis part 8 of the coil 4 is set on the wire 3 side, and the wire 3 is heated. Because the shorter axis part 8 is thus set to be close to the wire 3, the wire 3 can be heated sufficiently. Since an electrode 6 which is not to be heated desirably is positioned on the side of the longer axis part 9, heating power to the electrode 6 is reduced. Heating of the unnecessary part can thus be restricted, thereby deterioration of electron emission characteristics by emission of residual gas at a metal inner part can thus be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency heating apparatus for shield wire sputtering of an electron gun used for manufacturing a cathode ray tube and a method for heating a shield wire.

[0002]

2. Description of the Related Art A shield wire for an electron gun is heated from the outside of the glass of the electron gun using a high frequency coil and sputtered inside the neck portion of a cathode ray tube. The conventional high frequency coil has an annular shape.

[0003]

Since the shield wire is smaller than the structure of the electron gun, the conventional annular high-frequency coil has a problem in that the electrode portion which does not need to be heated is also heated. . As an improved coil for getter flash of a color cathode ray tube, for example, Japanese Utility Model Publication No. 1-222239 is known. However, there was no effective means for the shield wire. Therefore, residual gas inside the metal is released due to heating of an unnecessary portion, which causes a problem that electron emission characteristics are deteriorated.

An object of the present invention is to provide a high-frequency heating device equipped with a high-frequency coil for shield wire sputtering and a method of heating a shield wire, which can suppress heating of an unnecessary portion of an electron gun as much as possible.

[0005]

A high frequency coil for achieving the above object is characterized by having a non-annular shape.

In order to achieve the above object, a method of heating a shield wire uses a high-frequency coil having a non-circular shape,
It is characterized in that the shield wire is heated with the minor axis portion side facing the shield wire.

[0007]

The high-frequency coil has a non-circular shape, and the short axis portion side is used as the shield wire direction. As a result, the shield wire side has a narrow gap with the high-frequency coil and the shield wire side has a wide gap with the high-frequency coil in the direction perpendicular to the shield wire side, so that the heating power for heating the unnecessary portion is drastically reduced. As a result, only the target shield wire portion is heated intensively.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 2, the shield wire 3 of the electron gun 2 arranged on the neck portion 1a of the cathode ray tube 1 is heated by the high frequency coil 4 arranged on the outer periphery of the neck portion 1a. A current is supplied to the high frequency coil 4 from the heater 5.

As shown in FIG. 1, the shield wire 3
Surrounds the bead glass 7 holding the electrode 6. The glass around the electron gun is not shown. The high frequency coil 4 is formed in a non-ring shape, for example, an elliptical shape, and is made of a copper pipe or the like as a coil material. Here, in the high frequency coil 4, the diameter of the major axis portion 9 is at least twice the diameter of the minor axis portion 8.

Therefore, the shield wire 3 is heated with the short shaft portion 8 of the high-frequency coil 4 placed on the shield wire 3 side. That is, since the short shaft portion 8 of the high frequency coil 4 is close to the shield wire 3, the shield wire 3 can be sufficiently heated. Further, since the electrode 6 which is not desired to be heated is located on the long axis portion 9 side of the high frequency coil 4, the heating force applied to the electrode 6 is significantly reduced. Since there is the shield wire 3 from the short axis portion 8 side of the high frequency coil 4, there is almost no force for heating the electrode 6.

[0011]

According to the present invention, the shield wire can be heated without unnecessary heating of the electron gun electrode of the cathode ray tube, so that the deterioration of the electron emission characteristics due to the emission of the residual gas inside the metal can be prevented.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a high-frequency coil for shielded wire and a method for heating a shielded wire according to the present invention.

FIG. 2 is a schematic configuration diagram of a cathode ray tube and a high frequency heating device.

[Explanation of symbols]

 3 Shield wire 4 High frequency coil 8 Short axis part 9 Long axis part

Claims (3)

[Claims] 1. A method for heating a shield wire for an electron gun for a cathode ray tube, wherein a shield wire for an electron gun for a cathode ray tube is sputtered into a neck portion of the cathode ray tube by using a high frequency coil, wherein a high-frequency coil having a non-circular shape is used. The method for heating a shield wire of an electron gun for a cathode ray tube, comprising: heating the shield wire by arranging the short axis side of the shield wire in the direction of the shield wire. 2. A high-frequency heating device comprising a high-frequency coil for heating a shield wire of an electron gun for a cathode ray tube and sputtering the shield wire in a neck portion of the cathode-ray tube, wherein the high-frequency coil has a non-annular shape. High frequency heating device. 3. The high frequency heating apparatus according to claim 2, wherein the non-circular high frequency coil has a major axis portion having a diameter of at least twice as large as a minor axis portion.