JPH05275032A - Image display device - Google Patents

Abstract

PURPOSE:To display the image having high quality under the dewing condition by annularly locating the dewing preventing agent in the periphery of a windscreen container, of which front surface is made of glass. CONSTITUTION:Dewing preventing agent 30 is annularly located in the outer surface of a windscreen container 9, of which front surface is made of glass, to separate the water film due to the dewing into the back plate 10 side and the windscreen container 9 side. As a result, the electric potential of the outer surface of the windscreen container 9 upper than the dewing preventing agent 30 is less than the grounding potential to eliminate the influence to the distribution of electric potential inside of the windscreen container 9. Especially, change of a collision position, where the electron beam collides with the phosphor, near the wall surface is eliminated. Consequently, an image display device, of which image quality is not deviated under the dewing condition, is obtained.

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 for video equipment.

[0002]

2. Description of the Related Art Heretofore, a cathode ray tube has been mainly used as a color television image display device. However, a cathode ray tube has a very long depth compared with a screen, and it is impossible to manufacture a thin television receiver. Met. Therefore, EL display elements, plasma display elements, liquid crystal display elements, etc. have been developed as flat panel display elements, but they are all insufficient in terms of performance such as brightness, contrast and color reproducibility. Therefore, for the purpose of displaying a high-quality image similar to that of a cathode ray tube on a flat device using an electron beam,
2. Description of the Related Art There is an image display apparatus in which a screen on a screen is divided into sections in a matrix form without any gap, and an electron beam is deflected and scanned for each section to cause a phosphor to emit light, thereby forming a color television image as a whole. Referring to the drawings below,
An example of the above-mentioned conventional image display device will be described.

FIG. 2 shows the configuration 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 electron beam extraction electrode, 4 is a signal electrode, 5 and 6 are focusing electrodes, 7 is a horizontal deflection electrode,
Reference numeral 8 is a vertical deflection electrode, in which these components are housed in a glass container 9 and a back plate 10 and the inside of the container is evacuated. The line 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 such line cathodes 2 are provided at appropriate intervals in the vertical direction. These line cathodes 2 are formed, for example, by coating an oxide cathode material on the surface of a tungsten wire. The back electrode 1 is made of a flat plate-shaped conductive material and is provided in parallel with the line cathode 2. The extraction electrode 3 is formed of a conductive plate that faces the back electrode 1 through the line cathode 2 and has a row of through holes 11 provided at appropriate intervals in the horizontal direction 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 is composed of a row of vertically elongated conductive plates 12 arranged at predetermined positions at positions facing each of the through holes 11 in the extraction electrode 3, and each of the conductive plates has an extraction electrode. Similar through holes 13 are provided at positions facing the through holes 11 of No. 3 of FIG. The shape of the through hole 13 may be an ellipse or a rectangle, or may be an elongated slit shape in the vertical direction. Focusing electrode 5
Is made of a conductive plate having through holes 14 at positions facing the through holes 13 of the signal electrode 4. The shape of the through hole 14 may be circular, elliptical, or slit-shaped. Focusing electrode 6
Has a slit hole 15 vertically connected at a position facing the through hole 14 of the focusing electrode 5. Slit hole 15
The shape of may be a round hole, an ellipse, or a rectangular shape. The horizontal deflection electrode 8 is composed of a conductive plate 16 and a conductive plate 16 which are connected to each other at two comb-like ends which are meshed with each other at an appropriate interval on the same plane.
The space 18 formed between the conductive plates 16 and 17 is opposed to the through slit hole 15 of the focusing electrode 6. As shown in FIG. 2, the vertical deflection electrode 8 has a structure in which conductive plates 19 and 20 connected at the ends thereof, that is, two comb-shaped conductive plates 19 and 20 are meshed with each other in the same plane at appropriate intervals. Consists of. The screen 21 is configured by applying a phosphor 22 that emits light when irradiated with an electron beam to the inner surface of the glass container 9 and adding a metal back layer (not shown) thereon. In addition, the extraction electrode 3, the signal electrode 4, the focusing electrodes 5 and 6, the horizontal deflection electrode 7,
The vertical deflection electrodes 8 are joined together with an insulating adhesive (not shown) to form an integral electrode block 24.

The operation of the image display device configured as described above will be briefly described. First, the wire cathode 2 is heated by passing a heater current in order to facilitate electron emission.
Appropriate voltage is applied to the back electrode 1, the line cathode 2 and the extraction electrode 3 in a heated state to emit a sheet-like electron beam from the surface of the line cathode 2. The sheet-shaped electron beam is divided into a plurality of pieces by the through hole 11 of the extraction electrode 3 and becomes a large number of electron beam streams 23. This electron beam flow 23 is generated by the signal electrode 4
The passing amount is adjusted individually for each electron beam flow according to the image signal applied to the. Next, the electron beam that has passed through the signal electrode 4 is focused and shaped by the electrostatic lens effect of the through holes 14 and 15 of the focusing electrodes 5 and 6, and then the adjacent conductive plates 16 and 17 of the horizontal deflection electrode 7 and The vertical deflection electrodes 8 are horizontally and vertically deflected by the potential difference applied to the adjacent conductive plates 19 and 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, causing the phosphor to emit light.

When a television screen is vertically and horizontally divided into a matrix to form a group of subsections 25, one electron beam separated as described above is made to correspond to each subsection, and an electron beam is generated. By deflecting and scanning only within each small section, the entire screen can be displayed on the screen. Further, by controlling the RGB video signal corresponding to each pixel by the signal electrode 4, a television moving image can be reproduced.

[0006]

However, such a conventional image display device has the following problems. When the side surface of the front glass container 9 is condensed due to a temperature difference or the like, FIG.
As shown in, a thin water film is formed on the surface of the glass container 9 and the back plate 10 is electrically connected. At this time, since the back plate 10 is at the ground potential, the outer surface of the front glass container 9 is at the ground potential, and the potential of the inner surface of the front glass container 9 is lowered. As a result, the potential distribution inside is affected, and in particular, the collision position of the electron beam in the vicinity of the wall surface with the phosphor is changed, causing deterioration in image quality.

In view of the above problems, the present invention is to provide an image display device which displays a high quality image even in a dew condensation state.

[0008]

In order to achieve the purpose of sanity, the present invention arranges an anti-condensation agent in an annular shape on the outer peripheral portion of a front glass container, so that the outer surface of the front glass container and the back plate are formed when dew condensation occurs. It is designed to be electrically separated by a dew condensation preventing agent.

[0009]

In the structure of the image display device of the present invention described above, the dew condensation preventing agent annularly arranged on the outer peripheral portion of the front glass container allows the outer surface of the front glass container and the back plate to be electrically connected by a water film at the time of dew condensation. Will be prevented. as a result,
Even when condensation occurs, the outer surface of the front glass container is not electrically separated from the back plate and does not reach the ground potential.Therefore, it does not affect the potential distribution inside the front glass container. The position of collision of the beam with the phosphor is not changed, and the image quality is not deteriorated.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image display device according to an embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows a front glass container and an anti-condensation agent added to an image display device according to an embodiment of the present invention. A front glass container 9 displays an image when electrons collide with the phosphor surface. 10 is a back plate, which is adhered to the front glass 9 to seal the container. An electrode block 24 controls an electron beam. A dew condensation preventive agent 30 separates the water film formed by the dew condensation into the front glass container 9 side and the back plate 10 side.

When dew condensation occurs on the outer surface of the front glass container 9 of the image display device constructed as described above, the water film due to dew condensation is formed on the rear plate 10 side by the dew condensation preventive agent 30 as shown in the enlarged view of FIG. The front glass container 9 is separated. As a result, the upper surface of the front glass container 9 from the dew condensation preventing agent 30 does not reach the ground potential, and does not affect the potential distribution inside the front glass container, and particularly the electron beam phosphor near the wall surface does not affect the phosphor. It does not change the collision position.

[0013]

As is apparent from the above description of the embodiments, according to the present invention, the water film due to dew condensation is separated into the back plate side and the front glass container side by the dew condensation preventing agent, so that the dew condensation on the front glass container is caused. The outer surface of the upper glass container does not reach the ground potential from the inhibitor, does not affect the potential distribution inside the front glass container, and does not particularly change the collision position of the electron beam near the wall surface with the phosphor. Thus, it is possible to provide an image display device in which the image quality is not deteriorated even in the dew condensation state.

[Brief description of drawings]

FIG. 1 is a sectional view of an outer container of an image display device according to an embodiment of the present invention.

FIG. 2 is a partially exploded perspective view showing the configuration of a conventional image display device.

FIG. 3 is a sectional view of an outer container of a conventional image display device.

[Explanation of symbols]

 9 Front glass container 10 Back plate 24 Electrode block 30 Dew condensation inhibitor

Claims (1)

[Claims] 1. A front glass container having an inner surface coated with a phosphor, a back plate facing the front glass container, and a back face formed of a single conductive plate in a space sandwiched between the back plate and the front glass container. An image display device comprising an electrode, a plurality of line cathodes, and an electron beam extraction electrode composed of one or a plurality of conductive plates, a signal electrode, a focusing electrode, a horizontal deflection electrode, and a vertical deflection electrode, wherein the front glass container An image display device with an anti-condensation agent added to the outer circumference in a ring shape.