JPH04245156A - Linear cathode of picture display element - Google Patents

Abstract

PURPOSE:To reduce mechanical strain of an electrode group and influence on deterioration of picture quality due to dislocation between a phosphor and an electron beam and minimize electric power necessary for heating a linear cathode by installing a linear cathode of a picture display element which uses a direct heated linear electrode as an electron beam source. CONSTITUTION:A spirally wound copper wire 12 is processed to be stuck under pressure to both ends, deviated from the effective screen region of a picture, of the tungsten core 11 of a linear cathode and oxide cathode material 14 is applied to the surfaces of the portion other than both ends, so that the resistances of both ends of the linear cathode are thereby lowered to restrict wasteful power consumption and also the thermal expansion of an electrode group can be minimized to reduce a mechanical strain thereof.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line cathode for an image display device using a directly heated line cathode as an electron beam source.

0002

2. Description of the Related Art Image display elements will be explained below.

As shown in FIGS. 3 and 4, the image display element includes a back electrode 1, a line cathode 2 as an electron beam source, a beam extraction electrode 3, and a group of electrodes (beam flow control electrode, horizontal deflection electrode, vertical deflection electrode). 4 (composed of electrodes, focusing electrodes, etc.) and a screen plate 5 are arranged in order from the back to the front, and these are arranged inside the vacuum container consisting of the flat surface container 9 and the back container 7. This is the configuration that is housed in.

The back electrode 1 functions to push out the generated electron beam only in the forward direction. The line cathode 2 is horizontally stretched on a fixed base 8 so as to generate an electron beam that is linearly distributed in the horizontal direction. It is provided.

The beam extraction electrode 3 is constituted by a conductive plate having a large number of through holes 6 arranged at predetermined intervals in the horizontal direction facing each of the line cathodes 2. It functions to take out the electron beam through the through hole 6.

The electron beam taken out through the through hole 6 is subjected to effects such as controlling the amount of the electron beam, deflecting it, converging it, etc. as required by the electrode group 4, and then the phosphor coated on the screen 5 is exposed. Irradiate it to emit light and display an image.

A shaded area of the screen 5 inside the surface container 9 is an effective screen area 10 where an image is displayed.

The line cathode 2 of the conventional image display element is constructed by coating the surface of a tungsten core wire with a diameter of 10 to 30 μm with an oxide cathode line material. The electrode group 4 is configured to have an area larger than the area of the effective image screen area 10 to prevent disturbance of the electric field at the end of the electrode group 4 from disturbing the electron beam trajectory and causing image disturbance. , the line cathode 2 is also longer.

[0009]

[Problems to be Solved by the Invention] However, in the above conventional configuration, the wire cathode becomes longer and the electric power for heating the wire cathode increases, which causes thermal expansion of the electrode group and mechanical damage to the electrode group. This has the problem of generating distortion, and also of causing a positional shift between the phosphor coated on the screen and the electron beam, resulting in deterioration of image quality.

The present invention solves the above-mentioned conventional problems, and aims to provide a line cathode for an image display element that minimizes the power required for heating the line cathode, which causes image quality deterioration. do.

[0011]

[Means for Solving the Problem] In order to solve this problem, the wire cathode of the image display element of the present invention has a conductive core wire at both ends of the wire cathode corresponding to the portion outside the effective screen area of the image. Composed of fine metal wires attached in a spiral shape,
Alternatively, it has a structure in which a coating is applied by electroplating.

0012

[Operation] This structure lowers the resistance at both ends of the line cathode, thereby suppressing wasteful power consumption in areas outside the effective screen area of the image.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a spirally wound copper wire 12 is crimped at both ends of the tungsten core wire 11 of the wire cathode outside the effective screen area of the image, and the surface of the other portions is oxidized. Apply cathode material 14.

[0015] With this configuration, the resistance at both ends of the line cathode can be reduced. A second embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 2, both ends of the tungsten core wire 11 of the wire cathode outside the effective screen area of the image are coated with tungsten 13 by electroplating to increase the wire diameter, and the surface of the other portions is coated with tungsten 13. An oxide cathode material 14 is applied.

With this configuration, the resistance at both ends of the line cathode can be lowered. As described above, according to this embodiment, thin metal wires are spirally attached to the core wires at both ends of the wire cathode corresponding to the portions outside the effective screen area of the image, or coated with electroplating. The electrical resistance of is reduced, reducing wasteful power consumption,
Thermal expansion of the electrode group can be minimized, mechanical distortion of the electrode group can be reduced, and the influence on image quality deterioration can be reduced.

[0018]

Effects of the Invention As is clear from the description of the embodiments described above, the present invention provides a method in which a highly conductive metal wire is spirally wound around the core wire at both ends of a wire cathode and then crimped, or a highly conductive metal wire is wrapped around the core wire at both ends of a wire cathode. By coating the material, it is possible to realize an excellent line cathode for an image display element that can minimize the power required to heat the line cathode, which causes image quality deterioration.

[Brief explanation of the drawing]

FIG. 1 is a side view of a main part of a line cathode of an image display element according to a first embodiment of the present invention.

FIG. 2 is a side view of a main part of a line cathode of an image display element according to a second embodiment of the present invention.

[Figure 3] An exploded perspective view showing the configuration of the main parts of the image display element.

[
Figure 4: Exploded perspective view of image display element

[Explanation of symbols]

11 Core wire 12 Copper wire 14 Oxide cathode material

Claims (2)

[Claims] 1. An image display element comprising a back electrode, a line cathode as an electron beam source, a beam extraction electrode, an electron group, a screen plate, and a vacuum container, the image display device comprising: A wire cathode for an image display element in which a highly conductive metal wire is spirally wound and crimped around a core wire at both ends of the wire cathode corresponding to a portion outside the screen area. 2. The line cathode for an image display element according to claim 1, wherein the core wires at both ends of the line cathode are coated with a highly conductive metal material.