JP3158868B2 - Image display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device for video equipment.

[0002]

2. Description of the Related Art Conventionally, a cathode ray tube is mainly used as a color television image display device. However, a cathode ray tube has a very long depth as compared with a screen, and it is impossible to manufacture a thin television receiver. It was possible.
Accordingly, EL display elements, plasma display elements, liquid crystal display elements, and the like have been developed as display elements on a flat plate, but all of them are insufficient in performance such as luminance, contrast, and color reproducibility. Therefore, in order to display a high-quality image comparable to a cathode ray tube on a flat panel device using an electron beam, the screen on the screen is divided into matrix-shaped sections without gaps, and the electron beam is applied to each section. 2. Description of the Related Art There is an image display apparatus that emits phosphors by deflection scanning to form a color television image as a whole.

Hereinafter, the above-described conventional image display device will be described with reference to the drawings. FIG. 2 is an exploded perspective view of a conventional image display device.

In FIG. 2, 1 is a back electrode, 2 is a line cathode as an electron beam source, 3 is an extraction electrode, 4 is a signal electrode,
5 and 6 are focusing electrodes, 7 is a horizontal deflection electrode, and 8 is a vertical deflection electrode. These components are housed in a front glass container 9 and a positive glass plate 10, and the inside of the container is evacuated. .

The reason why the four corners of the back electrode 1 are chamfered is that an electrode fixing base (not shown) for supporting the various electrodes and the linear cathode 2 is placed.

[0006] The linear cathodes 2 are stretched in the horizontal direction so as to generate an electron flow uniformly distributed in the horizontal direction, and a plurality of the linear cathodes 2 are provided in a vertical direction at appropriate intervals. . These line cathodes 2 have, for example, a structure in which an oxide cathode material is coated on the surface of a tungsten wire.

The back electrode 1 is formed by applying a conductor on the back glass plate 10, and is provided in parallel with the linear cathode 2. The extraction electrode 3 faces the back electrode 1 via the linear cathode 2 and has through holes 1 provided at appropriate intervals in the horizontal direction.
It consists of a conductive plate having one column on a horizontal line facing each line cathode. The through-hole 11 is circular in the embodiment, but may be elliptical or rectangular, or may be slit-shaped.

The signal electrode 4 comprises a row of a plurality of vertically elongated conductive plates 12 arranged at predetermined positions at positions facing each of the through holes 11 in the extraction electrode 3.
Each conductive plate has a similar through-hole 13 at a position facing the through-hole 11 of the extraction electrode 3. Through hole 1
The shape of 3 may be an ellipse or a rectangle, or may be a vertically elongated slit.

The focusing electrode 5 is formed of a conductive plate having a through-hole 14 at a position facing the through-hole 13 of the signal electrode 4. The shape of the through hole 14 may be a circle, an ellipse, or a slit. The focusing electrode 6 has a slit hole 15 vertically connected to a position facing the through hole 14 of the focusing electrode 5. The shape of the slit hole 15 may be a round hole, an ellipse, or a rectangular shape.

The horizontal deflection electrode 7 is composed of conductive plates 16 and 17 which are connected to each other at two comb-shaped ends which are meshed with each other at an appropriate interval on the same plane.
The space 18 formed therebetween faces the through slit hole 15 of the focusing electrode 6.

As shown in FIG. 2, the vertical deflection electrode 8 is formed by engaging the conductive plates 19 and 20 connected at the ends, that is, the two comb-shaped conductive plates 19 and 20 in the same plane at an appropriate interval. It has a combined configuration.

The screen 21 is formed by applying a phosphor 22 that emits light by irradiation with an electron beam to the inner surface of the glass container 9 and adding a metal back layer (not shown) thereon.

Further, the above-mentioned extraction electrode 3, signal electrode 4,
Focusing electrodes 5 and 6, horizontal deflection electrode 7, vertical deflection electrode 8
Are joined with an insulating adhesive (not shown here) to form an integral electrode block 24.

Further, the above configuration will be described with reference to FIG. 3A and 3B show a configuration of a main part of a conventional image display device. FIG. 3A is a cross-sectional view, and FIG. 3B is a plan view of a rear glass plate 10. Electrode fixing base 100
3 is adhered to the back glass plate 10 at the chamfered portion of the end of the back electrode 1 as shown in FIG. 3, and supports the electrode block 24 and the like. Further, a gap between the electrode fixing base 100 and the back electrode 1 is provided for electrical insulation therebetween.

The operation of the image display apparatus configured as described above will be briefly described with reference to FIG. 2 again.

First, the line cathode 2 is heated by flowing a heater current to facilitate electron emission. In a heated state, an appropriate voltage is applied to the back electrode 1, the line cathode 2, and the extraction electrode 3 to emit a sheet-like electron beam from the surface of the line cathode 2. The sheet-like electron beam is divided into a plurality of pieces by the through-holes 11 of the extraction electrode 3 to form a large number of electron beam flows 23. The passing amount of the electron beam stream 23 is individually adjusted by the signal electrode 4 according to the video signal applied to the signal electrode 4.

Next, the electron beam passing through the signal electrode 4 is
The conductive plates 16 and 17 adjacent to the horizontal deflection electrode 7 and the conductive plate 1 adjacent to the vertical deflection electrode 8 after being focused and formed by the electrostatic lens effect of the through holes 14 and 15 of the focusing electrodes 5 and 6.
It is deflected horizontally and vertically by the potential difference applied to 9,20. Further, a high voltage (for example, 10 KV) is applied to the metal back layer of the screen 21, and the electron beam is accelerated to high energy and collides with the metal back to cause the phosphor to emit light.

When the television screen is divided vertically and horizontally into a matrix to form an aggregate of small sections 25, the electron beams separated as described above correspond to each of the small sections. Is deflected and scanned only within each subsection, so that the entire screen can be projected on the screen. In addition, by controlling the RGB video signals corresponding to the respective pixels with the signal electrodes 4, a television moving image can be reproduced.

[0019]

However, according to the above configuration, the following problems occur. That is, as shown in FIG. 3, the electron beam flow 23 emitted from the line cathode 2 is normally pushed to the electrode block 24 side by applying a potential lower than the potential of the line cathode 2 to the back electrode 1. .

However, the end of the linear cathode 2 closest to the electrode fixing base 100 is located in the gap between the electrode fixing base 100 and the back electrode 1 as shown in FIG. Since it is the surface of the back glass plate 10 which is a body, the potential of the back electrode 1 has not sufficiently reached, and is higher than the back electrode potential.

As a result, in this portion, the electric field is disturbed, and a part of the electron beam normally pushed to the electrode block 24 side generates a floating electron group (straight emission group) as shown in FIG. ), And travels along the inner surface of the entire glass container 9 as shown in FIG.
Reach These floating electrons (straight emission)
Since the light does not pass through the electrode block 24, it emits low-luminance light irrelevant to the image, and causes deterioration in image quality.

The present invention has been made in view of the above problems, and has as its object to provide an image display apparatus in which stray electrons (straight emission) causing the above-described image quality deterioration do not occur.

[0023]

In order to solve the above-mentioned problems, an image display device according to the present invention is provided with a back electrode having a shape covering the electrode fixing base in three directions or the entire circumference. Features.

[0024]

Conventionally, the floating electrons (straight emission) generated from the linear cathode flow from the insulating portion at a higher potential than the back electrode in the gap between the electrode fixing base and the back electrode to the front glass container. However, in this case, by providing the back electrode so as to surround all or three directions of the electrode fixing base,
Since the potential of the insulating portion in the gap between the electrode fixing base and the back electrode can be maintained at the perceived potential of the back electrode, the high potential portion on the back glass plate that causes stray electrons (straight emission) is eliminated. Can be.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image display device according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a main configuration of an image display device according to the present embodiment.
FIG. 1B is a cross-sectional view, and FIG. 1B is a plan view of the rear glass plate 10. The same parts as those of the conventional device shown in FIGS. 2 and 3 of the conventional example are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 1, reference numeral 1 denotes a back electrode, which is usually formed by applying a conductor to the inner surface of the back glass plate 10 as in the conventional example. Here, as shown in FIG. The electrode fixing base 100 is formed so as to surround the three directions .

As a result, the potential near the rear glass plate 10 at the ends of the line cathodes 2 at the upper and lower ends is kept close to the potential of the rear electrode 1, so that the floating electron group (shown by the dotted line in FIG. 1) flows. (Straight emission) e hardly occurs. In addition, as shown in FIG. 1, even a small amount of floating electrons (straight emission) are blocked by the back electrode 1 and do not flow to the front glass container 9, so that the image quality does not deteriorate.

It is also possible to lower the potential near the rear glass plate 10 at the ends of the upper and lower ends of the linear cathode 2 by shortening the distance between the electrode fixing base 100 and the rear electrode 1. According to this method, the electrode fixing base 100
The electrical insulation between the back electrode 1 and the
Since high precision is required for the 00 configuration, it is not suitable for practical use.

Here, the electrode fixing base 100 and the back electrode 1
Is not shortened, so that the insulation between them is not affected.

[0030]

As described above, according to the present invention, by providing a back electrode having a shape that covers the three directions or the entire circumference of the electrode fixing base, the generation of stray electrons (stray emission) that causes deterioration of image quality can be reduced. Provided is a high-quality image display device that does not generate stray electrons (straight emission) because the potential of the insulating portion that is higher than the back electrode in the gap between the electrode fixing base and the back electrode can be kept low. it can.

In this case, since the distance between the electrode fixing base and the back electrode does not need to be shorter than in the conventional example, there is no danger of dielectric breakdown between the electrode fixing base and the back electrode, and there is no practical problem. It can be said that the invention has excellent effects.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of a main part of an image display device according to an embodiment of the present invention. FIG. 1B is a plan view of a rear glass plate of the image display device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a conventional image display device.

3A is a cross-sectional view of a main part of a conventional image display device, and FIG. 3B is a plan view of a rear glass plate of the conventional image display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode 2 Wire cathode 9 Front glass container 10 Rear glass plate 21 Screen 23 Electron beam flow 24 Electrode block 100 Electrode fixed base e Floating electron group (straight emission)

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01J 31/12

Claims (1)

(57) [Claims] 1. A front glass container having a phosphor applied inside thereof and a rear glass plate closing a rear opening of the front glass container are opposed to each other, and a conductor is applied to an inner surface of the rear glass plate. A back electrode formed by
In the internal space sandwiched between the front glass container and the rear glass plate, the rear electrode, a plurality of linear cathodes, an extraction electrode composed of a single or a plurality of conductive plates, a signal electrode, a focusing electrode, and a horizontal electrode. An electrode block in which a deflecting electrode and a vertical deflecting electrode are stacked back and forth, and a line shadow on the rear glass plate.
At the end of the pole, at the chamfered end of the back electrode.
An image display device comprising: an electrode fixing base positioned to support the electrode block; and a back electrode having a shape surrounding three directions or the entire circumference of the electrode fixing base.