JPH04249047A - Flat plate type image display device - Google Patents

Abstract

PURPOSE:To enhance the picture quality of an image display device of flat plate type by lessening tube deflective abberation of electron beam. CONSTITUTION:The aperture dia. in the same direction as the electron beam deflection of deflecting electrodes 17, 18 of at least part of through holes in a convergence electrode 1 shall be no less than 1.2 times as great as the spacing in the same direction as the electron beam deflection of the beam passing part of the deflecting electrodes 17,18.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel image display device used in color television receivers, computer terminal displays, and the like.

0002

[Prior Art] In recent years, flat panel image display devices have been actively developed, and liquid crystal displays (LCD), electroluminescent displays (EL), light emitting diode displays (LED), etc. have appeared on the market. It is inferior to color cathode ray tubes in terms of resolution and full color. Therefore, with the aim of displaying color television images on a flat device using an electron beam that can produce high-quality images comparable to that of a cathode ray tube, the screen was divided into matrix-like sections without gaps, and each There is an image display device that deflects and scans an electron beam to cause a phosphor to emit light for each category, creating a color television image as a whole, and development has progressed to the point where it rivals cathode ray tubes in terms of image quality and full color. I'm here.

An example of the above-mentioned conventional image display device will be described below with reference to the drawings. As a conventional image display device, for example, Japanese Patent Laid-Open No. 1-173553 is known. FIG. 4 is a horizontal cross-sectional view (cross-sectional view on the Y plane) showing a part of the basic structure of the conventional example, and shows a state in which the electron beam is not deflected. In FIG. 4, 11
is a back electrode, 12 is a linear hot cathode as an electron beam source,
13 is an electron beam extraction electrode, 14 is a signal electrode, 15
16 is a first focusing electrode, 16 is a second focusing electrode, 17 is a horizontal deflection electrode, and 18 is a vertical deflection electrode, and these components are housed in a vacuum container (not shown). Linear hot cathode 12
are stretched in the horizontal direction (parallel to the X-ray in the figure), and although not shown in the figure, a plurality of them are provided in the vertical direction at regular intervals. These linear hot cathodes 12 are constructed, for example, by coating the surface of a tungsten wire with an oxide cathode material.

The back electrode 11 is made of a plate-shaped conductive material and is provided parallel to the linear hot cathode 12. The extraction electrode 13 is a plate-shaped electrode that faces the back electrode 11 via the linear hot cathode 12 and has a through hole for the electron beam at a location corresponding to the linear hot cathode 12 . The signal electrode 14 consists of a row of vertically elongated conductive plates (not shown in the figure) installed at predetermined intervals in positions facing each of the through holes in the extraction electrode 13. , has a similar through hole at a position opposite to the through hole of the extraction electrode 13. The first focusing electrode 15 is made of a conductive plate having through holes at positions facing each through hole of the signal electrode 14 . The second focusing electrode 16 is the first focusing electrode 15
It has a slit hole at a position opposite to the through hole. The horizontal deflection electrode 17 is composed of a conductor connected by two comb-shaped ends that are interlocked with each other on the same plane (not shown in the figure). The space thus formed faces the slit hole of the second focusing electrode 16.

The horizontal width of the slit hole of the second focusing electrode 16 is less than the horizontal width of the space created between the horizontal deflection electrodes 17. Although not shown in the figure, the vertical deflection electrode 18 is composed of conductive plates connected at their ends, that is, two comb-shaped conductive plates that are interlocked with each other on the same plane with a space between them. The screen 19 is constructed by coating the inner surface of a glass container 21 with a phosphor 20 that emits light when irradiated with an electron beam, and adding a metal back layer (not shown) thereon.

The operation of the image display device configured as described above will be explained. First, while heating the linear hot cathode 12, appropriate voltages are applied to the back electrode 11 and the extraction electrode 13, and the voltage of the linear hot cathode 12 is individually controlled. can be generated. The above sheet-shaped electron beam 2
2 is then divided by the through hole of the extraction electrode 13 and reaches the through hole of the signal electrode 14. At this time, the voltage of the signal electrode 14 is controlled over time to display the picture element. The amount of electron beam passing is adjusted according to the video signal.

The electron beam 22 that has passed through the signal electrode 14 then reaches the first focusing electrode 15 and the second focusing electrode 16, and is focused and shaped by passing through the through hole and the slit hole, and then passes through the horizontal deflection electrode. 17 and between the conductors of the vertical deflection electrode 18 (deflection voltage), the beam is electrostatically deflected horizontally and vertically. Further, a high voltage of, for example, 10 kV is applied to the metal back layer of the screen 19, and the electron beam 22 is accelerated and collides with the metal back, causing the phosphor to emit light. FIG. 5 is an enlarged partial horizontal sectional view of the vicinity of the horizontal deflection electrode 17 in FIG.

[0008]

[Problems to be Solved by the Invention] In such a conventional configuration, when the electron beam passes through the slit hole, the beam spreads in the horizontal direction as shown in FIG. A high-density electron beam passes through. Moreover, a part of it may collide with the second focusing electrode 16. Therefore, the trajectory of the electron beam changes rapidly in this vicinity,
When the electron beam is deflected by the horizontal deflection electrode 17, the deflection aberration of the electron beam spot on the screen 19 becomes large, and as a result, the diameter of the spot in the horizontal direction cannot be made sufficiently small when the electron beam is deflected. This indicates that the image quality of the flat panel image display device is not satisfactory in terms of color purity, and that it is an obstacle to achieving higher definition.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems, reduce deflection aberration when an electron beam is horizontally deflected, and provide a flat panel image display device with good image quality.

0010

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides that the diameter of the opening in the same direction as the electron beam deflection direction of the deflection electrode of at least a part of the through-hole of the focusing electrode is The spacing is 1.2 times or more the distance in the same direction as the electron beam deflection direction of the beam passing portion.

[0011]

[Function] According to the above configuration, when the electron beam passes through the slit hole of the second focusing electrode, it is possible to maintain a sufficient distance from the second focusing electrode, and as a result, the trajectory of the electron beam is changed in the vicinity of the electrode. There is no sudden change, and the deflection aberration of the electron beam spot on the screen can be reduced.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 3. Note that in the figure, the same parts as those in the conventional example shown in FIG. That is, the feature of the present invention lies in the second focusing electrode 1, which has a vertically connected slit hole at a position opposite to the through hole of the first focusing electrode 15.

That is, FIG. 2 is an enlarged view of the vicinity of the second focusing electrode 1 and horizontal deflection electrode 17 in FIG. 1, and the trajectory of the electron beam is conceptually shown by arrows.

First, while heating the linear hot cathode 12, an appropriate voltage is applied to the back electrode 11 and the extraction electrode 13.
By individually controlling the voltages of the linear hot cathodes 12, a sheet-shaped electron beam 22 can be generated from the linear hot cathodes 12. However, only a part of the electron beam trajectory is shown in the figure. The sheet-shaped electron beam 22 is then horizontally divided into a plurality of pieces by the through hole of the extraction electrode 13 and reaches the through hole of the signal electrode 14.
At this time, by controlling the voltage of the signal electrode 14 over time, the amount of electron beam passing is adjusted individually for each electron beam according to the video signal for displaying the picture element.

The electron beam 22 that has passed through the signal electrode 14 then reaches the first focusing electrode 15 and the second focusing electrode 1, and is focused by passing through their through holes and slit holes.
After shaping, the potential difference (deflection voltage) applied between the conductors of the horizontal deflection electrode 17 and between the conductors of the vertical deflection electrode
(not shown) are horizontally and vertically electrostatically deflected. Furthermore, the metal back layer of the screen 19 has, for example, 10
A high voltage of kV is applied, and the electron beam 22 is accelerated and collides with the metal back, causing the phosphor to emit light.

At this time, the degree of change in the horizontal diameter of the electron beam spot with respect to the horizontal deflection on the screen 19 is determined by the horizontal width d of the slit hole of the second focusing electrode 1.
1 and the horizontal distance d between the conductors of the horizontal deflection electrode 17
Depends on 2. This will be explained using FIG. 3. FIG. 3 shows that in the configuration of this embodiment, the horizontal distance d2 between the conductors of the horizontal deflection electrode 17 is constant (0.3 mm), and the horizontal width d1 of the slit hole of the second focusing electrode 1 is set as a parameter. This is an example in which changes in the horizontal spot diameter with respect to the horizontal deflection distance on the screen were measured.

[0017] d1 and d2 are equal (d1=0.3mm)
Compared to the case, d1 is 1.33 times d2 (d1=0.4
mm), as shown in FIG. 3, the degree of change in the horizontal diameter of the electron beam spot with respect to horizontal deflection is significantly reduced.

That is, the electron beam 22
When passing through the slit hole, it is possible to take a sufficient distance from the second focusing electrode 1, which reduces deflection aberration when horizontally deflected, and as a result, the horizontal diameter of the spot when deflected is sufficiently small. This makes it possible to obtain satisfactory characteristics in terms of image quality, color purity, etc. of the flat panel image display device. Furthermore, since the horizontal spot diameter as a whole becomes smaller, it is possible to further improve the definition of this display device.

Furthermore, when increasing d1 to 0.5 mm, there is little difference from the case when d1 is 0.4 mm, and adverse effects such as an increase in the required deflection voltage due to changes in voltage conditions may occur. I don't like it very much. These d
Regarding the relationship between 1 and d2, the inventors have determined that d1 is 1 of d2.
．． It has been confirmed through experiments that it is appropriate to set it to 2 times or more, but preferably 1.6 times or less. In this embodiment, the horizontal width d1 of the slit hole of the second focusing electrode 1 (for example, 0.
4 mm) is 1.33 times the horizontal distance d2 (for example, 0.3 mm) between the conductors of the horizontal deflection electrode 17.

Although the above embodiment has a configuration in which the signal electrode 14 is a part of a plurality of plate-shaped electrodes, the same applies to a configuration in which the back electrode 11 is divided into a plurality of parts and used as signal electrodes instead. There is an effect.

In the above embodiment, two focusing electrodes are used.
Although we have described the above case, it can also be applied to the case where the number of focusing electrodes is further increased. It is sufficient if it is 1.2 times or more.

In the case of such a configuration, if the deflection electrodes are made of two comb-like conductive plates that are interlocked with each other with an appropriate space on the same plane, it is suitable for a flat panel image display device due to its compactness. There is.

[0023]

As described above, according to the present invention, the diameter of the opening in the same direction as the electron beam deflection direction of the deflection electrode in at least a part of the through hole of the focusing electrode is the same as that of the electron beam passing portion of the deflection electrode. By having a structure in which the direction is 1.2 or more times the distance in the same direction, it is possible to reduce deflection aberration and obtain a flat panel image display device with good color purity and the like.

[Brief explanation of the drawing]

FIG. 1 is a horizontal sectional view showing the basic structure of a flat panel image display device according to an embodiment of the present invention.

[Figure 2] Partially enlarged sectional view of Figure 1

[Fig. 3] Horizontal deflection characteristic diagram using the aperture diameter d1 of the through-hole of the second focusing electrode in Fig. 2 as a parameter.

[Figure 4] Horizontal sectional view showing the basic structure of a conventional flat panel image display device

[Figure 5] Partially enlarged sectional view of Figure 4

[Explanation of symbols]

1 Second focusing electrode (focusing electrode) 11 Back electrode (electron beam control electrode group) 12 Linear hot cathode (electron source) 13 Extraction electrode (electron beam control electrode group) 14
Signal electrode (electron beam control electrode group) 15 First focusing electrode (focusing electrode) 17 Horizontal deflection electrode (deflection electrode) 18 Vertical deflection electrode (deflection electrode) 19 Screen (light emitting means) 20 Phosphor (light emitting means) 21 Glass container (Light emitting means) 22 Electron beam

Claims (2)

[Claims] 1. An image display device comprising, in a vacuum container, an electron source, an electron beam control electrode group for extracting and controlling a beam from the electron source, and a light emitting means for emitting light by the impact of the electron beam. At least a part of the electron beam control electrode group is composed of a plurality of conductive plates located on the same plane, and includes a deflection electrode that deflects the electron beam, and a conductive electrode that is installed on the electron source side of the deflection electrode and has a plurality of through holes. a focusing electrode made of a plate, and an opening diameter of at least a portion of the through-hole of the focusing electrode in the same direction as the electron beam deflection direction of the deflection electrode is in the electron beam deflection direction of the electron beam passing portion of the deflection electrode. A flat panel image display device characterized in that the distance in the same direction is 1.2 times or more. 2. The flat panel image display device according to claim 1, wherein the deflection electrode is composed of two comb-shaped conductive plates that are interlocked with each other with an appropriate space between them on the same plane.