JPS61124031A - Electron gun of image display unit - Google Patents

Abstract

PURPOSE:To stabilize an electric field distribution of an electron gun by preparing an electroconductive film on spacer surfaces facing linear negative electrodes in the position in which a rear electrode is insulated from vertical focusing electrodes. CONSTITUTION:While spacers 2 in an electron gun of an image display unit keep the distance between a rear electrode 1, in which a transparent electroconductive film 1a is formed on one side, and vertical focusing electrodes 4 to be constant, charging by electron beams, released from the linear negative electrodes 3 is kept uniform with the transparent electroconductive films 2a in order to uniformize the electric field being composed in an electron gun. The transparent electroconductive films 2a are formed on spacer surfaces in the position in which the rear electrode 1 is insulated from the vertical focusing electrodes 4. Together with insulating the rear electrode 1 from the vertical focusing electrodes 4, the electroconductive films can be formed all over the surfaces of the spacers 2. Therefore, stabilization as the composition of the electron gun can be realized and irregularity of brightness in the image display unit can be removed, with improvement and stabilization of picture quality being realized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electron gun for an image display device in the field of video information equipment.

Conventional configurations and their problems Traditionally, cathode ray tubes have been mainly used as display devices for displaying color television images, but conventional cathode ray tubes have a much longer depth than the screen, making it difficult to use for thin TVs. It was impossible to fake a John receiver.

In addition, as flat display devices, EL (electroluminescence) display devices, plasma display devices, liquid crystal display devices, etc. have recently been developed, but all of them have poor image quality such as brightness, contrast, and color reproducibility. It has insufficient performance and has not yet been put into practical use.

Or, even if it is put into practical use, its scope is extremely limited.

The purpose is to achieve a device that can display color television images on a flat display device using electron beams, and the screen is divided vertically into multiple sections and each section is divided into two sections. The electron beam is deflected vertically into a cylinder to display a plurality of lines, and is further divided horizontally into a plurality of sections so that phosphors such as R, Ci, and B are emitted in each section. A system has been developed that displays a television image as a whole by controlling the amount of electron beam irradiated onto the R, G, B, etc. phosphors using color video signals. As shown in FIG. 1, the conventional flat plate-shaped image display device has a glass container 12 arranged in order from the rear to the front.
, back electrode 1, spacer 2, line cathode 3 as an electron beam source, vertical focusing electrodes 4, 4', vertical deflection electrode 6, electron beam flow control electrode 6, horizontal focusing electrode 7.7', horizontal deflection electrode 8, An electron beam accelerating electrode 9, an anode 10, and a glass container 11.12 are arranged, and the components are housed in the glass container 11.12, which is then evacuated. 1st
In a broad sense, the configuration of the electron gun of the image display device shown in the figure includes a back electrode 1, a spacer 2, a line cathode 3, and a vertical focusing electrode 4.
．． 4', a vertical deflection electrode 5, an electron beam flow control electrode 6, a horizontal focusing electrode 7°7/, a horizontal deflection electrode 8, and an electron beam acceleration electrode 9. On the other hand, in a narrow sense, the configuration including the back electrode 1, spacer 2, line cathode 3, and vertical focusing electrode 4 among the above-mentioned electrode group is called an electron gun. Hereinafter, the electron gun in the present invention refers to this configuration in a narrow sense.

The back electrode 1 has the function of pushing forward and at the same time restricting the electron beam emitted from the line cathode 3 as an electron beam source, and is made of a glass plate, and on the surface facing the line cathode 3, For example, a transparent conductive film made of tin oxide and indium oxide is formed by vapor deposition. In addition to this, a conductive film such as gold may be deposited. The line cathode 3 is the first
As shown in the figure, it is stretched horizontally, and a plurality of such wire cathodes 3 (only four are shown here) are provided in the vertical direction at appropriate intervals. These wire cathodes 3 are constructed by applying an oxide cathode material such as barium oxide, strontium oxide, or calcium oxide to the surface of a tungsten wire of, for example, 13 to 30 μΦ by electrodeposition or the like. The spacer 2 is a glass plate with a thickness of 3 to 6 m, and serves to maintain a constant distance between the back electrode 1 and the vertical focusing electrode 4. The vertical focusing electrode 4 is made of 426 alloy (Ni:42
%, Cr: 6%, Fe: 52%), etc., with a thickness of 0.
It consists of an upper border of a metal conductive plate with a thickness of 1 to 0.2 mm, and silver, platinum, gold, etc. is formed on the surface by vapor deposition or wet plating to a thickness of several microns.

The vertical focusing electrode 4 functions to draw forward and focus the electron beam emitted from the linear cathode 3.

However, in the above configuration, as shown in FIG. 2, since the spacer 2 is made of dielectric glass, the electron beam emitted from the line cathode 3 causes
Since charges are generated on the surface of the spacer and the electric field in the electron gun is not stabilized, it has the disadvantage that brightness unevenness occurs on the anode surface of the image display device.

OBJECTS OF THE INVENTION The present invention eliminates the above-mentioned conventional drawbacks, and aims to stabilize the structure of an electron gun.

Structure of the Invention The present invention includes a back electrode, a vertical focusing electrode, a spacer in which a conductive film is formed on a surface facing the line negative source while maintaining a constant distance between the back electrode and the vertical focusing electrode, and a line. This is an electron gun consisting of a cathode and is extremely advantageous in terms of quality and performance of the image display device.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 shows the configuration of an electron gun of an image display device in one embodiment of the present invention. In Figure 3, 2 is
The glass spacer 2a is a transparent conductive film formed by vapor deposition or the like on the surface of the spacer 2 facing the line cathode 3, and the spacer 2 is perpendicular to the back surface t&1 on which the transparent conductive film 1a is formed on one side. It serves to maintain a constant distance from the focusing electrode 4, and at the same time, the transparent conductive film 2a uniformizes the charge caused by the electron beam emitted from the line cathode 3.
The electric field in the configuration of the electron gun can be kept uniform. The transparent conductive film 2a on the spacer surface is formed at a position such that the back electrode 1 and the vertical focusing electrode 4 are insulated. Alternatively, as shown in FIG. 4, the back electrode 1 and the vertical focusing electrode 4 may be insulated and a conductive film may be formed on the entire surface of the spacer 2.

Therefore, the structure of the electron gun can be stabilized, uneven brightness of the image display device can be prevented, and image quality can be improved and stabilized.

Effects of the Invention As described above, the present invention provides a conductive film that is formed on the spacer surface facing the linear cathode at a position that insulates the back electrode and the vertical focusing electrode. Since the influence of the electron beam can be eliminated and the electric field distribution in the electron gun can be stabilized, the image quality of the image display device can be stabilized for a long time, which has great practical effects.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the structure of an electron gun showing the structure of a flat image display device. 1... Back electrode, 2... Spacer, 2
a... Conductive film.

Claims (1)

[Claims] Between the anode and the back electrode, a plurality of line cathodes, a vertical focusing electrode for focusing, deflecting, and accelerating the electron beam emitted from the line cathodes, a vertical deflection electrode, and an electron beam flow control electrode;
In an image display device in which various electrode groups such as a horizontal focusing electrode, a horizontal deflection electrode, and an electron beam accelerating electrode are interposed, a planar back electrode with a conductive film formed on one side of the electrode group, a vertical focusing electrode, A spacer comprising: a linear cathode; and a spacer that maintains a constant distance between the back electrode and the vertical focusing electrode, and has a conductive film formed on a surface facing the linear cathode at a position insulating from the back electrode and the vertical focusing electrode. An image display device electron gun.