JPH07141998A - Electron beam type display device - Google Patents

Abstract

PURPOSE:To provide a display device having a high contrast ratio and excellent picture quality by restraining contrast lowering due to reflected electrons from an anode surface in a thin type electron beam type display device. CONSTITUTION:This device is constituted so that a phosphor layer 11, an aluminum metal layer 12, and a carbon layer 13 are laminated in order on the inner surface (vacuum side) of a face glass 10, and the carbon layer 13 is formed by laminating graphite fine particles having a ratio of a thickness to a diameter of 1:10 or larger and a spherical volume conversion means particle diameter of 2mum or less. Also, this carbon layer 13 is formed by laminating a quantity of the graphite fine particles of 20mug/cm<2> or more and 220mug/cm<2> or less per unit area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device using an electron beam, and more particularly to a display device capable of realizing high image quality display with a high contrast ratio of a display screen.

[0002]

2. Description of the Related Art A display device using an electron beam is widely used as a display device in video information equipment and is in a very important position. Various means have been devised to improve the image quality of a display device using this electron beam.

As one of the methods, a method of forming a carbon layer or a boron layer containing carbon atoms or boron atoms on the surface of the anode electrode to suppress backscattered electrons is also a CRT as a method for solving the problem of image quality deterioration. Was temporarily tried in the development process of. In this attempt, it was confirmed that the carbon layer is effective in suppressing backscattered electrons (see, for example, US Pat. No. 2,
878, 411).

As a structural improvement method, CR is used.
Preventing re-entry of reflected electrons into the anode electrode by trapping reflected electrons from the anode electrode surface by setting the T-tube side wall surface to the same high voltage as the anode, or by providing a shadow mask immediately in front of the anode electrode. A method of suppressing halation was also devised, and this structure has become the mainstream of current high-quality CRTs.

On the other hand, as one of the thin electron beam type display devices that have recently appeared, one having a structure as shown in FIG. 3 has appeared. This structure and operation will be described in some detail.

In FIG. 3, reference numeral 4 denotes a cathode line of an electron beam generating source, and an electron beam 6 emitted from the heated cathode line is focused and deflected by a flat plate electrode lens group 3 and a back electrode 5 to be face glass. The phosphor 2 of the anode electrode is made to emit light by being incident on the anode electrode on 1. The electron beams emitted from the holes of the flat plate electrode group each form a small CRT, and a set of these forms a screen.

Since this thin electron beam type display device has not been developed yet, it has a problem to be solved in terms of image quality and performance.

[0008]

In the structure of the thin electron beam type display device described above, the effect of trapping backscattered electrons cannot be expected even if the side wall surface of the electron beam type display tube is at the same high voltage as the anode. It is considerably difficult in terms of structure and manufacturing process to use a method of trapping reflected electrons from the surface of the anode electrode by providing a shadow mask immediately before the anode electrode.

In addition, a method of forming a layer of carbon atoms or boron atoms on the surface of the anode electrode to suppress backscattered electrons has not been sufficiently studied so far.
No significant effect could be expected.

Moreover, in the thin electron beam type display device,
Since the distance between the anode electrode and the low potential electrode is much smaller than that of the CRT, the electric field in the vicinity of the anode electrode is considerably high, and when the carbon layer is formed of particles, a large Coulomb force is exerted on the particles. Therefore, problems such as scattering and dropping of carbon particles have occurred.

In view of the above problems, it is an object of the present invention to provide a highly reliable electron beam type display device which can obtain a high contrast display screen without using a special electron trap structure. And

[0012]

In order to solve the above problems, in the electron beam type display device of the present invention, a phosphor layer, a metal layer and a carbon layer are laminated in this order on the inner surface of the face glass, and The carbon layer is formed by laminating graphite fine particles having a thickness-to-diameter ratio of 1:10 or more and a spherical volume-converted average particle diameter of 2 μm or less, and the carbon layer contains graphite fine particles of 20 μg / unit area per unit area. cm
^Two or more and 220 μg / cm ² or less are laminated so that they are formed.

[0013]

In the structure of the electron beam display device of the present invention, the carbon layer is formed by laminating graphite fine particles having a thickness-diameter ratio of 1:10 or more and a spherical volume-converted average particle diameter of 2 μm or less. Since the graphite particles are uniformly dispersed and laminated, it is possible to suppress the unevenness of the carbon layer thickness after firing the anode at a high temperature.

As a result, the effect of suppressing the electron reflection of the carbon layer can be made more uniform and more reliable.

Further, by setting the above ratio of thickness to diameter,
Since the graphite particles are aligned side by side on the surface of the metal layer,
The contact area between the particles and the metal layer is increased, the adhesion strength of the particles is significantly increased, and the reliability can be improved.

Further, by controlling the amount of graphite particles to be stacked in an amount of 20 μg / cm ² or more and 220 μg / cm ² or less per unit area, the decrease in electron energy in the carbon layer can be kept below a certain level, and the number of electrons above a certain level can be reduced. Since the reflection suppressing effect can be imparted, it is possible to realize an electron beam type display device having a good image quality with a high contrast with a small decrease in luminance.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electron beam type display device of the present invention will be described below with reference to the drawings and tables.

FIG. 1 is an enlarged configuration diagram of an anode portion in an embodiment of the display device of the present invention. In FIG. 1, 1
Reference numeral 0 denotes a face glass, and a phosphor layer 11, an aluminum metal thin layer 12, and a graphite fine particle laminated carbon layer 13 are laminated inside the face glass (vacuum side). Table 1 shows the thickness unevenness and the degree of halation of the carbon layer when the ratio of the thickness to the diameter and the particle diameter of the graphite particles used in the carbon layer 13 of this example were changed. The adhesion strength of this graphite particle layer is also shown.

[0019]

[Table 1]

As can be seen from (Table 1), graphite particles having a small thickness-to-diameter ratio generally have a large particle size and tend to cause large thickness unevenness of the carbon layer. Further, particles having a small thickness / diameter ratio and a small particle size show relatively good characteristics.

However, in such a graphite particle layer, the graphite adhesion strength is weak and there is a possibility that problems may occur in terms of reliability.

As shown in (Table 1), it is found that graphite particles having a thickness-diameter ratio of 1:10 or more and a spherical volume-converted average particle diameter of 2 μm or less are desirable as the graphite particles used in the carbon layer. .

FIG. 2 shows the display luminance and the halation / luminance ratio when the amount of graphite particles laminated on the carbon layer 13 of this embodiment is changed. In the figure, the value when the amount of graphite is 0 μg / cm ² is shown as a relative value with 100% as the value.

The amount of graphite particles is 20 per unit area.
If it is less than μg / cm ² , there is almost no effect of suppressing halation. Further, if it is 220 μg / cm ² or more per unit area, the display brightness becomes extremely low, which causes a problem. In order to achieve both brightness and halation characteristics, the amount of graphite per unit area is 20 μg / cm ² or more and 220 μg / c or more.
It is necessary to be m ² or less.

[0025]

As described above, by using the electron beam type display device having the carbon layer of the present invention, it is possible to suppress halation while maintaining high display brightness, and display unevenness. And reliability can be improved.

[Brief description of drawings]

FIG. 1 is an enlarged view of an anode electrode portion of an electron beam type display device according to an embodiment of the present invention.

FIG. 2 is a diagram showing display luminance and halation / luminance ratio when the amount of graphite particles to be laminated is changed.

FIG. 3 is a schematic perspective view of a structural example of a thin electron beam type display device.

[Explanation of symbols] 1 face glass 2 phosphor stripe 3 plate electrode lens group 4 cathode line 5 back electrode 6 electron beam 10 face glass 11 phosphor layer 12 aluminum metal thin layer 13 graphite fine particle laminated carbon layer

Claims (3)

[Claims] 1. A display device which emits a phosphor by irradiation of an electron beam, wherein a phosphor layer, an electron-transmissive metal layer and a carbon layer are sequentially laminated on an inner surface of a face glass, and the carbon layer has a thickness. An electron beam type display device, characterized in that it is formed by laminating graphite fine particles having a diameter ratio of 1:10 or more and a spherical volume-converted average particle diameter of 2 μm or less. 2. A display device in which a phosphor emits light when irradiated with an electron beam, wherein a phosphor layer, an electron-permeable metal layer, and a carbon layer are sequentially laminated on an inner surface of a face glass, and the carbon layer is graphite. 20 μg of fine particles per unit area
An electron beam display device, which is formed by laminating an amount of not less than / cm ^{2 and not} more than 220 μg / cm ² . 3. A display device which emits a phosphor by irradiation of an electron beam, wherein a phosphor layer, an electron-transmissive metal layer and a carbon layer are sequentially laminated on an inner surface of a face glass, and the carbon layer is graphite. 20 μg of fine particles per unit area
The electron beam type display device according to claim 1, wherein the electron beam display device is formed by laminating an amount of not less than / cm ^{2 and not} more than 220 μg / cm ² .