JPH05217515A - Electron gun for cathode-ray tube - Google Patents

Abstract

PURPOSE:To prevent induced occurrence of cathode damages and noise obstructions, by providing an opening at a part of insulative support members for an electron gun and thereby suppressing creeping discharge occurring along the surface of the insulative support members. CONSTITUTION:In an electron gun comprising electron guns 2, 3, 4, and 5 retained and fixed by insulative support members 1, an opening portion 7 is provided in an insulative support member 1 in an embedding interspace between the electrodes 4 and 5 so as to enable preventing occurrence of an creeping discharge.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron gun for a cathode ray tube, and more particularly to an electron gun for a cathode ray tube effective for improving withstand voltage characteristics.

[0002]

2. Description of the Related Art A conventional electron gun for a cathode ray tube (hereinafter referred to as an electron gun) has an insulating support 1 and a plurality of electrodes 2, 3, 4, 5 as shown in FIG. Electrodes 2, 3, 4, 5
The surface of the insulating support 1 is interposed between the embedded portions of the insulating support 1.

During operation of the cathode ray tube, the electrodes 2, 3, 4, 5
The specified voltage is applied to each, especially the electrode 5
Is applied with a high voltage of about 20 KV to 30 KV, and a high voltage corresponding to 20 to 30% thereof is applied to the electrode 4, so that the potential difference between both electrodes is as high as 10 KV to 24 KV.

[0004]

As described above, in the conventional electron gun, between the electrodes where a high potential difference is generated, for example, as shown in FIG.
A potential difference of about 14 KV to 24 KV is generated between the electrodes 4 and 5 of. Further, since the surface of the insulating support is interposed between the electrode-embedded portions, the field emission electrons emitted from the low potential electrode 4 collide with the surface of the insulator to emit secondary electrons during the operation of the cathode ray tube. Further, there is a problem that a so-called in-tube discharge, which leads to a creeping discharge, occurs, causing damage to the cathode 6 due to the discharge energy at that time and noise disturbance due to a discharge flow.

It is an object of the present invention to provide an electron gun which does not cause noise damage due to damage to the cathode or discharge discharge.

[0006]

The present invention comprises a cathode,
In an electron gun for a cathode ray tube having a plurality of electrodes and an insulating support for holding and fixing the plurality of electrodes, an opening is provided in a part of the insulating support.

[0007]

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

FIG. 1 is a schematic block diagram for explaining a first embodiment of the present invention.

In the first embodiment, as shown in FIG. 1, the electrodes 2, 3, 4, and 5 are embedded and held and fixed in the insulating support 1, and the electrodes 4 and 5 are embedded. The insulating support 1 between the parts is provided with an opening 7. As a result, secondary electrons are not emitted or grown from the insulating support 1, and creeping discharge can be prevented.

FIG. 2 is a schematic block diagram for explaining the second embodiment of the present invention.

As shown in FIG. 2, the second embodiment has a structure in which a plurality of openings 7 having a small opening area are provided in order to improve the strength of the insulative support 1 to prevent creeping discharge. The prevention effect is equivalent to that of the first embodiment of FIG.

FIG. 4 is a distribution diagram of the creeping discharge starting potential difference between the embodiment of the present invention and the conventional electron gun.

As shown in FIG. 4, as compared with the conventional electron gun, the electron gun of this embodiment can improve the withstand voltage characteristic level of about 6.5 KV.

[0014]

As described above, according to the present invention, by providing an opening in a part of the insulating support, it is possible to easily emit and grow on the surface of the insulating support interposed between the electrodes where a high potential difference occurs. It is possible to block the secondary electrons that are generated by the opening and prevent the creeping discharge from occurring, so that it is possible to prevent damage to the cathode and noise interference.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram illustrating a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram illustrating a second embodiment of the present invention.

FIG. 3 is a schematic configuration diagram illustrating an example of a conventional electron gun.

FIG. 4 is a distribution diagram of a creeping discharge starting potential difference between an example of the present invention and a conventional electron gun.

[Explanation of symbols]

 1 Insulating Support 2, 3, 4, 5 Electrode 6 Cathode 7 Opening

Claims (1)

[Claims] 1. An electron gun for a cathode ray tube having a cathode, a plurality of electrodes, and an insulating support for holding and fixing the plurality of electrodes, wherein an opening is provided in a part of the insulating support. Electron gun for cathode ray tubes characterized by.