JPH07176279A - Flat plate image display device - Google Patents

Abstract

PURPOSE:To solve a bright streaking and arched condition of a raster by providing an electrostatic focusing potential applying means by placing the center of a hole of a focusing electrode eccentrically from the center of a hole of the other electrode, and dividing the focusing electrode into a plurality of parts. CONSTITUTION:An electrode of constituting an electron lens is provided with five sheets of electrodes, electron beam draw out electrode 2, signal electrode 3, focusing electrode 4, horizontal deflection electrode 5 and a vertical deflection electrode 6. A linear hot cathode wire 1 is extended in a horizontal direction, and a plurality of the wires are provided in a vertical direction through a suitable space. In a screen 43, a phosphor of emitting light by irradiation of an electron beam is applied to an internal surface of a glass vessel 33, and a metal pack layer is provided in a surface of the vessel. In this constitution, the focusing electrode 4 is divided in a vertical direction relating to the linear hot cathode wire 1, and a slight voltage difference is provided relating to the divided focusing electrode. In addition to dividing the electrode, the center of a plurality of holes in the focusing electrode is placed eccentrically from the center of a plurality of holes provided in the other electrode, to change an electron lens system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic lens structure of a flat panel CRT used for a color television receiver or a terminal display of a computer.

[0002]

2. Description of the Related Art In recent years, flat panel image display devices (flat
Research and development of flat panel CRTs as one of the displays) are being actively conducted. For example, JP-A-1-13045
Japanese Patent No. 3 discloses a flat plate CRT using a plurality of linear hot cathodes.

The present inventors have applied for a new electron lens structure for reducing the electron beam spot diameter of the conventional flat plate CRT.

This prior art example will be described below with reference to the drawings. The structure uses linear hot cathodes 1a and 1b formed in a vacuum container and a plurality of plate electrodes. Figure 4
4 (a) and 4 (b) are cross-sectional views of plate electrodes forming the electron lens system.

The electrodes forming the electron lens are provided with five electrodes: an electron beam extraction electrode 2, a signal electrode 3, a focusing electrode 4, a horizontal deflection electrode 5 and a vertical deflection electrode 6. The linear hot cathode 1 used as an electron source is horizontally stretched so as to generate an electron flow having a substantially uniform current density distribution in the horizontal direction, and a plurality of vertical hot cathodes 1 are vertically spaced at appropriate intervals. It is provided. In these linear hot cathodes 1, for example, an oxide cathode is applied to the surface of a tungsten wire having a core wire diameter of 15 to 30 μm.

The extraction electrode 2 is opposed to the back electrode via the linear hot cathode 1 and is arranged at an appropriate interval in the horizontal direction.
It is composed of a conductive plate having rows of substantially circular through holes of 1 to 0.3 mm on a horizontal line facing each linear cathode.

The signal electrode 3 is composed of a row of vertically elongated conductive plates arranged in a plurality of through-holes in the extraction electrode 2 at positions facing each other in the horizontal direction with a predetermined interval therebetween. A through hole of 0.1 to 0.3 mm is provided at a position facing the through hole of the extraction electrode 2.
The focusing electrode 4 is composed of a through hole of the signal electrode 3 and a conductive plate having a through hole of 0.3 to 0.5 mm at a position facing each other.

As shown in FIG. 5, the horizontal deflection electrode 5 has a structure in which a plurality of vertically elongated conductive plates are arranged in the horizontal direction and formed into a generally blind shape, and particularly in the middle of the row of through holes of the focusing electrodes 4. Conductive plates are arranged on the same plane so as to face each other.

As shown in FIG. 5, the vertical deflection electrode 6 is composed of conductive plates connected at their ends, that is, two comb-shaped conductive plates meshed with each other on the same plane at appropriate intervals. .

The screen 43 applies a phosphor that emits light by irradiation of an electron beam to the inner surface of the glass container 33,
A metal back layer (not shown) is provided on the surface.

The electron beam that has passed through the signal electrode 3 next reaches the focusing electrode 4 and is focused by the electrostatic lens effect of the through-hole, and the horizontal deflection electrodes 5 are joined together. A high voltage of 11 kV to 15 kV is applied to the metal back layer of 43 screens that are electrostatically deflected horizontally and vertically due to the potential difference applied between the adjacent conductive plates, and the electron beam is accelerated to high energy and metal It collides with the back and excites the phosphor to emit light.

[0012]

The landing of the electron beam obtained by such an electrode structure is caused by the positional deviation of each electrode hole, the variation of the electrode assembly accuracy, and the distortion of the stripes of the light emitting portion and the non-light emitting portion during the phosphor printing. And so on, it deviates from the desired landing position.

Such landing displacement often occurs. This landing shift causes color shift in the horizontal direction and uneven brightness in the vertical direction, which deteriorates the image quality.

The uneven brightness will be described in some detail. 2 on the screen 43 of FIG.
As shown in (b), at the joint between the raster covered by one linear hot cathode and the raster covered by the adjacent linear hot cathode, the horizontal brightness line (when the rasters are distant, the brightness horizontal line It appears as a streak, and when rasters overlap, it appears as a white streak due to increased brightness (hereinafter referred to as a horizontal brightness line).

There is also an image defect such as when the raster becomes arched (partially separates or overlaps) as shown in FIG. 6C mainly due to variations in the accuracy of the electrode itself and the accuracy of electrode assembly. It was

[0016]

[Means for Solving the Problems] In the case where a horizontal brightness line is visible or has a bow shape in a raster, in order to eliminate it, the landing shift of the electron beam is landed at a desired position. is there.

As a concrete means, the center of the hole of the focusing electrode 4 of FIG. 5 is made eccentric with the centers of the plurality of holes provided in other electrodes, and the focusing electrode voltage applying means is provided to divide the focusing electrode into a plurality of parts. As a result, the landing position is corrected and the landing is performed at a desired position, so that it is possible to solve the luminance horizontal line and the bowed state of the raster.

[0018]

According to the above means, the focusing electrode 4 is divided into a plurality of electrodes in the vertical direction with respect to the linear hot cathode.
It became possible to make partial electrical correction, and mainly solved the state of bowing of the raster, and the center of the plurality of holes provided in at least one of the plurality of electrodes was provided in the other electrode. By being eccentric with the center of multiple holes,
The electron lens system can change the beam landing position instead, and the electron beam can be landed at a desired position by the focusing electrode voltage applying means.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. This configuration is the same as that of the prior art, but the major difference is that the focusing electrode 4 of FIG. 5 is divided (three divisions in the same figure) as shown in FIG. 1B.

The orbit and landing of the electron beam of the electrode divided into a plurality of electrodes, in which the centers of the plurality of holes of the focusing electrode are eccentric with the centers of the plurality of holes provided in the other electrode, will be described.

FIG. 7 shows one side of the trajectory of the electron beam in the vertical section of FIG. 2 with respect to the central axes 131-132 (this is shown because the electron beam is symmetric with respect to the axes 131-132). Due to the omission). The electron beam emitted from the linear cathode passes through the extraction electrode in a direction away from the central axis in order to form a divergent lens between the extraction electrode and the linear cathode. Then, at the modulation electrode, the outermost beam is slightly scraped and passes through. The electron beam is focused on almost one point by a slightly strong focusing lens formed between the modulation electrode and the focusing electrode, and diverges again from the focusing point. In other words, the object has moved here.

Thereafter, the divergent beam is focused by the high voltage penetrating from the fluorescent screen and an electron lens having a strong focusing power formed by the vertical deflection electrode, and an electron beam spot diameter (object) of about 100 μm is formed on the fluorescent screen. Points).

Thus, the electron beam spot diameter is 100 μm.
In order to achieve m, it is important that the electron beam land at the desired position.

FIG. 7 shows a slight deviation from the desired landing position, and it is actually 20 to 30 μm due to the cause described in the above problem.
If the position deviates from the desired landing position, the electron beam spot diameter (object point) is not formed, and due to this, color misregistration due to multicolor printing, brightness lines, bowing, etc. are visible, resulting in image defects.

In order to solve these problems, this configuration is a method of changing the electron lens system to change the landing position of the electron beam to a desired position so that the landing can be performed at a desired position.

FIG. 2 is a landing diagram of the beam trajectories when the centers of the plurality of holes in the focusing electrode 4 in FIG. 1 are eccentric with the centers of the plurality of holes provided in other electrodes. You can see that the landing is changed instead of the electronic lens system.

In FIG. 2, the electron lens system is changed by the above means, and voltage applying means is provided to the focusing electrode 4 of FIG. 1 (a),
It is the figure corrected so that it can land at a desired position.

As shown in FIG. 1B, the focusing electrode is divided into
Fine landing correction can be performed by providing a slight voltage difference to each of the divided focusing electrodes.

Further, it is possible to solve the bow-shaped state of the raster which cannot be corrected conventionally by these correction methods.

In FIG. 3, in addition to the electrode division, when the center of the plurality of holes of the focusing electrode is decentered from the center of the plurality of holes provided in other electrodes, the electron lens system is changed, and the voltage applying means is provided. FIG. 6 is a trajectory diagram showing that the landing of the beam of FIG.

It can be seen that the electron beam is landed at the desired position. By these correction methods by the above-mentioned means, it is possible to obtain a better image without a horizontal brightness line and a bowed state.

[0032]

By the above means, the color shift due to the landing shift and the horizontal luminance line are not visible over the entire screen,
A good image can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a flat panel image display device according to an embodiment of the present invention.

FIG. 2 is a beam landing diagram when a focusing electrode is vertically displaced from an opposing electrode.

FIG. 3 is a beam landing diagram according to the configuration of the present invention.

FIG. 4 is a sectional view showing the structure of the present invention.

FIG. 5 is a perspective view of a conventional example.

FIG. 6 is an explanatory view of a problem of the conventional flat panel image display device.

FIG. 7: Beam landing diagram with conventional configuration

[Explanation of symbols]

 1 linear hot cathode 2 electron beam extraction electrode 3 signal electrode 4 focusing electrode 43 screen

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Makoto Kudo 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A vacuum vessel having at least one linear hot cathode, a plurality of electrodes for focusing or deflecting an electron beam emitted from the linear hot cathode, and light emission excited by the electron beam. And a display unit consisting of a striped non-light emitting portion, wherein the stretching direction of the linear hot cathode and the direction of the striped non-light emitting portion of the display unit substantially coincide with the scanning line direction, and the linear The electron beam emitted from the hot cathode once forms a cross point in the electrode group of the plurality of electrodes and then forms the cross point again in the display unit, and is provided on at least one electrode of the plurality of electrodes. A flat panel image display device, wherein the centers of the plurality of holes formed are eccentric with the centers of the plurality of holes provided in another electrode. 2. A flat panel image display device according to claim 1, wherein at least one of the plurality of electrodes having an eccentric hole is electrically separated into a plurality of electrodes.