JPH02288054A - Image display device - Google Patents

Abstract

PURPOSE:To prevent breaking of wire by peeling the surface oxide cathode material of a linear cathode in such a manner as leaving that portion of the material which locates between an image display portion, a vibration preventing member and insulating material. CONSTITUTION:Insulating materials 22a, 22b are provided while both in contact with a back electrode 20, and a linear cathode 15 is kept spaced apart from the back electrode 20 or a control electrode 18 by abutting of its outer periphery against the electrode 20 or 18. That portion of an oxide cathode material 27, 28 which is between the vibration preventing member 25, 26 and insulating material 22a, 22b of the linear cathode 15 is not peeled but left. When the linear electrode 15 is loaded with a heating current, the oxide cathode material 28 of the linear cathode 15 which is located on the side of a spring 23 thermally expands but is prevented from being peeled when made to abut against the insulating material 22b. Failure in image is thus prevented that may be caused by charge of beams, etc., caused when the material 28 peels off and is attached to a mesh-shaped hole provided through the control electrode 18.

Description

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

Conventional technology Traditionally, cathode ray tubes have been mainly used as display elements in color television image display units, but conventional cathode ray tubes are much longer in depth than the screen, making it difficult to manufacture thin television receivers. It was impossible to do so.

In addition, although EL display elements, plasma display elements, liquid crystal display elements, etc. have recently been developed as flat display elements, all of them are insufficient in terms of performance such as brightness, contrast, and color reproducibility. , it will take time to put it into practical use. Therefore, we aimed to achieve a device that can display color television images on a flat display device using electron beams, and we divided the screen into multiple sections in the vertical direction. The electron beam is deflected vertically for each line to display multiple lines, and then divided horizontally into multiple sections to display R-G- for each section.
The phosphors such as B are made to emit light sequentially, and the R-G,
The amount of electron beam irradiation on a phosphor such as B is controlled by a color video signal, and the entire device is used as a television image display device.

An example of the conventional image display device described above will be described below with reference to the drawings. 3 and 4 show conventional image display devices. In Fig. 3, 1 is a line cathode as an electron beam source, 2a and 2b are supports for positioning both ends of the line cathode, 3 is a mesh-like control electrode, 4 is a phosphor, 5 is a back electrode, 6a and 6b are containers. , 7 is the line cathode l
8 is a spring for tensioning the wire cathode I, and 8 is a fixing seat for fixing the wire cathode I.

The operation of the image display device configured as described above will be described below. Line cathode l as an electron beam source
is fixed to a plate spring 7 attached to a support base 2b so as to generate an electron beam distributed linearly in the horizontal direction, and then fixed to a fixed seat 8 and stretched in the horizontal direction. A plurality of linear cathodes 1 are provided at appropriate intervals (not shown).

Further, the wire cathode 1 is in contact with the insulators 9a and 9b, and is positioned in the height direction. This is shown enlarged in FIG. The wire cathode 1 is constructed by coating the surface of a tungsten wire 1 with a diameter of φlO to 20μ with an oxide cathode material IO.

Then, it is controlled by a control pulse so as to sequentially emit an electron beam for a certain period of time, and a heat current is applied at times other than the certain period of time to raise the temperature to generate an electron beam. Further, at the start, the line cathode 1 is loaded with the above-mentioned electron beam emission control pulse and heat current at the same timing. The back electrode 5 suppresses generation of electron beams from other line cathodes 1 other than the line cathode 1 which is controlled to emit electron beams at fixed time intervals, and pushes out the generated electron beams only in the forward direction. act. The mesh-like control electrode 3 is passed through horizontally long slits facing each of the line cathodes 1, and at the same time is deflected vertically or horizontally. Also, a round hole may be used instead of the slit. The phosphors 4 are provided with one pair of phosphors of three colors R, G, and B for each horizontally divided electron beam, and are coated in stripes in the vertical direction. .

After these components are inserted into the divided containers 6a and 6b, they are sealed with a frit or the like to maintain a vacuum inside.

However, in the above configuration, the line cathode l is the phosphor 4
As the size increases, the length increases accordingly,
For example, the insulators 9a and 9b of the wire cathode l
When the distance between the supporting parts becomes 100-, the diameter becomes 10-2
The natural frequency of the 0μm wire cathode 1 changes continuously during the process in which the temperature of the wire cathode 1 rises due to heat current at the start, and during this change, the control pulse of the wire cathode 1 that is applied at the same time at the start changes. When combined with the harmonic frequency of
At that point, the line cathode 1 will resonate, ±20~1
Vibration occurs for a long time with an amplitude of about 00 μm. When the line cathode 1 vibrates, its relative position with respect to the control electrode 3 changes, resulting in image defects such as wavering of the image and uneven brightness. In order to eliminate this drawback, as shown in FIG. 3 or 4, vibration preventing members 11 and 12 such as ceramic rings are provided on the wire cathode 1 to prevent vibration.

Problems to be Solved by the Invention However, as mentioned above, with the above configuration,
When a heat current is applied to the green shade 1 to generate an electron beam, the line cathode 1 reaches a high temperature of 700 to 800°C, and the vibration prevention member 11.1 from which the oxide cathode material 10 has been peeled off.
2 and the insulators 9a and 9b have a particularly high temperature, and the line cathode 1 is disconnected when the heat current of the green shade IF is turned on and off.

In view of the above drawbacks, the present invention provides an image display device in which the surface oxide cathode material of the wire cathode is left without Ml between the vibration prevention member and the insulator, thereby eliminating wire breakage. It is.

Means for Solving the Problems In order to solve the above problems, the image display device of the present invention includes:
The surface oxide cathode material of the wire cathode was removed except for the image display area, the space between the vibration prevention member and the insulator, and the rest was peeled off.

Effect of the present invention With the above-described configuration, the surface oxide cathode material of the wire cathode is not separated by ff1l between the vibration-preventing material and the insulator, so even when a heat current is applied, the temperature does not locally become high. Since there is no disconnection when the heat current is turned on or off, there is no possibility of image defects due to disconnection.

Embodiment Hereinafter, an image display device according to an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 15 denotes a conductive wire cathode 17a coated with a material having thermionic emission function, such as barium oxide 16.

17b is an insulating support that positions and supports both ends of the linear cathode 13; 18 is an electrode that controls the beam emitted from the linear cathode 15 to form a predetermined image; and 19 is an electrode that controls the beam that has passed through the control electrode 18. A phosphor that emits light upon collision to display an image; 20 is a back electrode 21a installed to facilitate the generation of thermoelectrons from the line cathode;

21b is a container, and 22a and 22b are for positioning the linear cathode 15 in the height direction. ! Green matter, 23 is negative to line cathode 15,
It is a spring that applies a load and is stretched, and 24 is a fixed seat that fixes it.

In FIG. 1, an insulator 22a in contact with the back electrode 20,
22b is provided, and the distance between the wire cathode 15 and the back electrode 20 or the control electrode 18 is maintained by contact with the outer diameter of the wire cathode 15. Further, the insulators 22a and 22b are located outside the image display section (i.e., the phosphor 19) and are located outside the insulating supports 17a and 17.
It is provided inward from b. Further, the oxide cathode materials 27 and 28 are left without being peeled off between the vibration prevention members 25 and 26 of the wire cathode 15 and the insulators 22a and 22b. The oxide cathode material 28 on the spring 23 side of the wire cathode 15 is configured to expand due to thermal expansion when a heat current is applied to the wire cathode 15, but not to come into contact with the insulator 22b and peel off. This is because the oxide cathode material 28 is peeled off and adheres to the holes of the mesh-like control electrode 18, thereby eliminating image defects caused by beam charging and the like. The wire cathode 15 is fixed by fixing it to the spring 23, stretching it under tension, and fixing it to the fixing seat 24. Control electrode 1 is attached to this assembled back electrode 20.
The image display device is completed by assembling the parts 8 and the like and sealing them with the containers 21a and 21b.

Effects of the Invention As described above, the present invention removes the surface oxide cathode material of the wire cathode, leaving the area between the image display area, the vibration prevention member, and the insulator, and peeling off the other part, and removing the material from the surface oxide material of the wire cathode in the area in contact with the wire cathode. That is, the temperature does not locally rise in the vicinity of the vibration prevention member, the insulator, the support base, the spring, and the fixed seat, and the temperature is uniform throughout, so that the wire cathode does not break. Furthermore, even if the wire cathode expands, the surface oxide cathode material contacts the insulator and does not peel off, resulting in image defects, making it possible to provide a high-quality image display device.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an image display device according to an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of its main parts, FIG. 3 is a cross-sectional view showing a conventional image display device, and FIG. 4 is a main part thereof. FIG. 15... line cathode, 18... control electrode,
19...phosphor, 20... back electrode,
16.27.28...Surface oxide cathode material, 2
2a, 22b... Insulator, 25.26...
...Vibration prevention member. Name of agent: Patent attorney Shigetaka Awano Haka1 person 15--Issho Kugai Gaichi Bafuda-Kuyakuba/627.2/f -Oxidation#Short&Right-barrel1211ZMeichi--Kuyoguotsu , 26-Ki #preventing eggs

Claims (1)

[Claims] An image display device including a line cathode that emits electrons, a limiting electrode that controls the flow of electrons, a phosphor that can receive the electrons and emit light, and a back electrode that is provided to cause the electrons to be emitted from the line cathode. An image display device according to the above, wherein the surface oxide cathode material of the linear cathode is peeled off except for the image display portion, the space between the vibration prevention member and the insulator.