JPH05343010A - Electron beam emitter - Google Patents

Abstract

PURPOSE:To provide an electron beam emitter for a high contrast large flat image display device by specifying the shape of a heat resistant insulating film provided on a cathode supporting means. CONSTITUTION:A stripe-shape control electrode 2 is formed on the surface of an insulating substrate 1 for which soda glass and the like is used, out of a conductive thin film. After a substrate 3a, for which a hole part is formed by etching and the like in a metal plate of 0.2mm, is formed, a heat resisting insulating material 3b such as Al2O3 or SiO2 is formed on the surface of the substrate 3a into a thickness of approximately 50mum, for a cathode supporting means 3. The method of formation is a flame melting film manufacturing, as generally called, and the films are formed on the substrate while the heat resisting materials are connected together in the granular form. The thermal spray film pattern to be formed on the substrate is carried out by providing masking. The pattern is formed in the vicinity of a point where a linear cathode 4 is abutted on the cathode supporting means 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam generating means for a flat panel display used for a color television receiver, a terminal display of a computer and the like.

[0002]

2. Description of the Related Art Many flat-plate CRTs as disclosed in, for example, Japanese Patent Application Laid-Open No. 1-130453 have been proposed. However, the problem of vibration of the linear hot cathode, which is a problem common to these many proposals, has been proposed. To solve the problem, JP-A-2-13277
There is a prior art disclosed in Japanese Patent Publication No. 39.

A vibration isolation technique for a conventional linear hot cathode of a flat plate CRT will be described below with reference to JP-A-2-132739.

FIG. 5 is a block diagram showing the main part of the above display device. A back electrode (signal electrode) 26, linear hot cathodes 27 a to 27 c as an electron beam source, and an electron beam extraction electrode 2 are provided in a vacuum container composed of glass containers 33 and 44.
8, cathode supporting means 37, focusing electrode 30, horizontal deflection electrode 3
1, a vertical deflection electrode 32.

The linear hot cathode 27 is horizontally stretched so as to generate an electron current having a substantially uniform current density distribution in the horizontal direction, and a plurality of linear hot cathodes 27 are provided in the vertical direction at appropriate intervals. There is. These linear hot cathodes 27 are formed, for example, by coating an oxide cathode on the surface of a tungsten wire.

The back electrode 26 is made of a flat plate-shaped conductive material and is provided parallel to the linear hot cathode.

The lead-out electrode 28 opposes the back electrode 26 via the linear hot cathode, and has a row of through holes 34 provided at appropriate intervals in the horizontal direction on a horizontal line facing each linear cathode. It consists of 36.

The horizontal deflection electrode 31 has a structure in which a plurality of vertically elongated conductive plates 40 are arranged in the horizontal direction and has a comb shape as a whole, and in particular, faces the middle of the row of the through holes 38 of the focusing electrode 30. The conductive plate 40 is arranged on the same plane.

The vertical deflection electrodes 32a and 32b are composed of conductive plates connected at their ends, that is, two comb-teeth-shaped conductive plates meshed with each other on the same plane at appropriate intervals. For the beam 48, the lower conductive plate 4
The pair of vertical deflection electrodes is formed by the pair of vertical electrodes 1b and the upper conductive plate 41b. The screen 43 applies a phosphor 42 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 operation of the image display device configured as described above will be described below. First, a voltage V1 is applied to the back electrode 26, and a voltage V2 higher than V1 is applied to the extraction electrode 28. Further, in order to heat the linear hot cathode and facilitate electron emission, if an appropriate voltage V0 such that V1 <V0 <V2 is applied with a heater current applied, the electric field on the surface of the linear cathode becomes positive and electrons The flow is emitted and accelerated towards the extraction electrode 28. Further, for example, if a voltage V0 satisfying V0> V2 is applied, the electric field on the surface of the hot cathode becomes negative, and the emission of electrons can be suppressed. Therefore, by individually controlling the voltage, the linear hot cathode is repeatedly emitted from the upper linear hot cathode so as to emit an electron beam for a fixed time, and each linear hot cathode has a uniform current density distribution in the horizontal direction. It is possible to generate a sheet-shaped electron beam.

The electron beam passing through the extraction electrode 28 is
Next, it reaches the focusing electrode 30, is focused by the electrostatic lens effect of the through hole 38, and is between the adjacent conductive plates 40, 40 of the horizontal deflection electrode 31, and the adjacent conductive plate 41 of the vertical deflection electrodes 32a, 32b. (A) Electrostatic deflection is performed horizontally and vertically by the potential difference applied between 41b. Further, a high voltage is applied to the metal back layer of the screen 43, and the electron beam is accelerated to high energy and collides with the metal back to excite the phosphor to emit light.

The heating of the linear hot cathode is pulse-driven as shown in FIG. That is, the linear hot cathode 27
A potential difference Vf is applied to both ends of a, and a heating current If is applied,
The linear hot cathode is Joule heated. Then, when the electron beam is extracted from the linear hot cathode, the heating current If is interrupted for about 1 ms to avoid a potential gradient due to energization,
The potential of the linear hot cathode is lowered (emission potential Ee) to take out electrons. Since the linear hot cathode is pulse-driven as described above, its temperature also changes and heat shrinks. Then, the linear hot cathode causes string vibration due to the contraction.

Also, when a small mechanical vibration is applied to the linear hot cathode, for example, from the outside of the vacuum container, the linear hot cathode causes string vibration.

When the linear hot cathode vibrates in a string, the distance between the linear hot cathode and the electron beam extraction electrode 28 changes and the electric field strength near the linear hot cathode changes. As a result, the amount of extracted electron beams fluctuates, which causes unevenness in the luminance of the phosphor.

In order to prevent the string vibration of the linear hot cathode, the cathode supporting means 37 is used. The cathode supporting means 37 will be described below. FIG. 6 shows a perspective view of the cathode supporting means. The cathode supporting means 37 is formed by providing a flat plate with a plurality of holes, and is arranged so as to abut the linear cathode 52. Since the cathode supporting means is required to have accuracy, easiness to make, heat resistance, insulation, etc., a metal plate provided with holes by etching or the like, a porous film of CaO, or a heat resistant insulating material such as alumina. Is coated. The cathode supporting means has a roughened surface or a multi-layered structure in order to reduce the heat conduction from the linear cathode.

[0016]

However, the above-mentioned conventional structure solves the problem of thermoconductivity, which is the cause of the temperature drop of the cathode, but causes the problem of charge-up. As shown in FIG. 7, in the electron beam emitted from the hot cathode, the electron beam passing through the extraction electrode is as small as 5 to 10%, and most of them collide with the electron beam extraction electrode. Some of the colliding electron beams are elastically scattered, or have secondary electron emission, and move again toward the hot cathode. Then, it reaches the surface of the cathode supporting member and is charged up due to the electrical insulating property of the heat insulating material. As a result, it becomes impossible to control the potential around the cathode to a desired value, and there is a drawback that the contrast of the image is lowered.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and solves the problem of charge-up on the surface of the cathode supporting means while maintaining the conventional function of the cathode supporting means as it is, thus achieving high contrast. Another object of the present invention is to provide an electron beam generator for a large flat panel image display device.

[0018]

In order to achieve this object, the electron beam generator of the present invention comprises an electron beam extraction electrode, a linear hot cathode, and a plurality of linear cathodes which are in contact with each other. And a linear hot cathode supporting means having substantially rectangular hole portions, and the supporting means is provided with a heat resistant insulating material between the substantially rectangular hole portions in the same direction as the linear cathode suspension direction. This is an electron beam generator characterized in that the application area of the material is limited.

Further, the electron beam generating apparatus of the present invention has a linear heat generating electrode, a linear hot cathode, and a linear heat contacting a part of the linear cathode and having a large number of substantially rectangular holes. A cathode supporting means, and a heat-resistant insulating material provided on the surface thereof to increase the electric conductivity of the heat-resistant insulating material.
An electron beam generator characterized in that it contains chromium oxide.

Further, the electron beam generating apparatus of the present invention comprises a linear heat generating electrode, a linear hot cathode, and a linear heat contacting a part of the linear cathode and having a large number of substantially rectangular holes. And cathode supporting means. Then, the supporting means coats a heat resistant insulating film on substantially the entire one surface thereof. Furthermore, other than between the substantially rectangular hole portions in the same direction as the linear cathode suspension direction,
This is an electron beam generator characterized in that a conductive thin film such as aluminum is applied so as not to charge up to an undesired part.

[0021]

With the above structure, it is possible to suppress the thermal contraction due to the heating of the thermal retreat and the string vibration due to the mechanical shock, and prevent the unwanted charge-up around the cathode. It will be possible.

[0022]

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

FIG. 1 shows the electron beam generating means of the present invention. That is, 1 is an insulating substrate using soda glass or the like, and stripe-shaped control electrodes 2 are formed on the surface by a conductive thin film. The cathode supporting means 3 forms a substrate 3a in which holes are formed on a metal plate having a thickness of 0.2 mm by etching or the like, and then a heat resistant insulating material 3b such as Al ₂ O ₃ or SiO ₂ is formed on the surface of the substrate 3a by about 50 μm. It is formed with the thickness of.
The forming method is generally called a sprayed film, and the heat-resistant insulating material is deposited on the substrate in a state where particles of the heat-resistant insulating material are bonded to each other.

The sprayed film pattern formed on the substrate is masked. The pattern is in the vicinity of the abutting portion of the linear cathode 4 that abuts the cathode supporting means 3, and details are shown in FIG.
It becomes the hatched part. The contact between the linear hot cathode and the cathode supporting means 3 is preferably point contact, but the operation of the present cathode is pulse-driven as described in the above-mentioned prior art.
Therefore, the linear hot cathode moves not only in the longitudinal direction but also in the thickness direction by at least 200 μm. Therefore, the heat-resistant insulating film needs an area for moving the contact portion and the linear hot cathode. The linear hot cathode has a core wire of 20 to 30.
The core wire is 7-12 μm around the tungsten wire of μm
The so-called spiral wire with the winding of is used.

FIG. 3 shows another embodiment of the present invention. 3 is similar to the configuration of FIG. 1, except that the sprayed film provided on the cathode supporting means is on the entire surface. At this time, chromium dioxide is added to the material of the sprayed coating in addition to conventional alumina. As a result, the physical properties of the heat-resistant insulating film can be increased in electrical conductivity with almost no change in its thermal characteristics. This prevents the cathode supporting means from being charged up.

Further, FIG. 4 shows another embodiment of the present invention.
Similar to FIG. 3, a heat resistant insulating film such as alumina is formed on the entire surface of one side having the cathode supporting means, and then a conductive thin film 3c such as aluminum is formed on the hatched portion of FIG. 4 by vapor deposition or the like. As a result, the problem of charge-up to an undesired part is solved.

In the embodiment described above, the substrate of the cathode supporting means is not limited to the one having the holes formed on the metal plate by etching or the like, and may be formed of an insulating material. ..

[0028]

As described above, according to the present invention, by limiting the film shape of the heat-resistant insulating film provided on the cathode supporting means or by adding chromium dioxide to the heat-resistant insulating film material, The problem of charge-up of the cathode supporting means could be solved by increasing the electric conductivity or by forming a conductive thin film such as aluminum on a part of the heat resistant insulating film. As a result, it is possible to realize an electron beam generating means for a flat panel image display for realizing a high-contrast image.

[Brief description of drawings]

FIG. 1 is a perspective view of an electron beam generating means in an embodiment of the present invention.

FIG. 2 is a detailed view of cathode supporting means of the electron beam generator of FIG.

FIG. 3 is a perspective view of an electron beam generating means according to another embodiment of the present invention.

FIG. 4 is a view showing a cathode supporting means of an electron beam generating means in another embodiment of the present invention.

FIG. 5 is a perspective view of a conventional flat panel CRT.

FIG. 6 is a diagram showing a heating waveform of a linear hot cathode.

FIG. 7 is a diagram showing a beam trajectory in the vicinity of an electron beam generating means of a conventional flat panel CRT.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating substrate 2 Control electrode 3 Cathode supporting means 3c Conductive thin film 4 Spacer 5 Linear cathode

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

Claims (3)

[Claims] 1. An electron beam extraction electrode, a linear cathode having a metal core wire, and a supporting means that is in contact with a part of the linear cathode and has a large number of substantially rectangular holes. An electron beam generator characterized in that the means comprises a heat-resistant insulating material between the substantially rectangular hole portions in the same direction as the suspension direction of the linear cathode. 2. An electron beam extraction electrode, a linear cathode having a metal core wire, and a supporting means that is in contact with a part of the linear cathode and has a large number of substantially rectangular hole portions. An electron beam generator characterized in that the means comprises a heat-resistant insulating material, and a conductive coating is provided on the surface of substantially the entire region except the linear cathode. 3. An electron beam extraction electrode, a linear cathode having a metal core wire, and a supporting means that is in contact with a part of the linear cathode and has a heat-resistant film on at least one surface thereof. At least two heat-resistant insulating materials for the supporting means
An electron beam generator having chromium oxide.