JPH0547297A - Display element - Google Patents

Abstract

PURPOSE:To increase the freedom degree of a display pattern, equalize a light emission brightness at a display part, and make an enclosure thin and light by forming an discontinuous high-resistance part inside a phoshor layer. CONSTITUTION:Electrodes 2 and 3 comprising resistance material for applying a voltage are provided on an insulation substrate 1 of glass or the like having a micro-interval between them, and a discontinuous high-resistance part 5 where fine grains 4 are dispersed is formed between them. Grains of phosphor 6 are applied on the part 5 to form a phosphor layer 7. For preventing contamination of the layer 7, an element is contained in vacuum, and a voltage is applied between the electrodes 2, 3, so the layer 7 emits light. Because a means to excite the layer 7 and emit light, that is the part 5, is formed inside the layer 7, and as the electrodes 2, 3 are formed on the same substrate 1 as the layer 7 and the part 5, a display pattern can be formed freely. The phosphor can be let to emit light in similar conditions at any part of the display pattern to equalize the light emission brightness, and an enclosure can be thin and light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display element, and more particularly to a display element adapted to excite a fluorescent substance to emit light.

[0002]

2. Description of the Related Art Conventionally, a CRT (Cathode-Ray-T) is used as a display element in an OA device such as a word processor and a personal computer because it has a merit that a clear image can be obtained and the brightness is high.
ube) has been widely used. The CRT is a device for displaying an electron emitted from an electron source by deflecting it by a magnetic field generated by a deflection coil to scan it and irradiating it on the R, G, B (for color display) phosphor surface. Yes, the distance moved by the deflection is the size of the display surface.

Further, as a flat type display element in which a fluorescent substance is excited by an electron beam to emit light, there is a fluorescent display tube. FIG. 6 shows the structure of the fluorescent display tube. As shown in FIG. 6, in the fluorescent display tube, a conductive phosphor layer 7 is formed on a glass substrate 12, and a filament 13 which is a linear cathode is stretched across the phosphor layer 7. Further, a grid 14 for accelerating and dispersing the electrons emitted from the filament 13 is arranged in the space between the filament 13 and the phosphor layer 7. In order to perform the display operation of such a fluorescent display tube, the filament 1
3, the grid 14 and the phosphor layer 7 are set to a high potential, electrons emitted from the filament 13 are accelerated and dispersed by the grid 14, and the phosphor layer 7 is irradiated with electrons to be excited.
Make it glow.

[0004]

The above-mentioned CRT and fluorescent display tube have the following problems. First, C
In the case of RT, as described above, the electrons emitted from the electron source are deflected and scanned, and the phosphor surface is irradiated to perform display, and the distance moved by the deflection is the size of the display surface. .. For this reason, the distance for moving the electrons becomes large, and the distance from the electron source to the phosphor surface becomes large in order to make use of this distance, and there are problems that the device becomes large and it is difficult to make it flat.

Further, in the case of the fluorescent display tube, since the filament which is the electron source is linear and the electron beam is radially emitted from the filament, the usable electron beam is limited, and as a result, the display pattern is changed. Is limited. For the same reason, the electron beam density is small in the corners of the display area, so that the emission color becomes light and the color unevenness easily occurs. Further, in order to uniformly irradiate the phosphor layer with the electron beam, the electron beam must be well dispersed to have a uniform density, and thus a grid is required between the filament and the phosphor layer. Therefore, there is a problem that the distance between the filament and the phosphor layer must be increased to a certain extent or more, and the thickness of the fluorescent display tube becomes large. Further, as the display area becomes larger, a vacuum envelope is formed due to the problem of breakdown voltage. The plate glass also has a large thickness, which causes a problem of increasing the thickness and weight of the element.

[0006]

The display element of the present invention comprises a discontinuous high resistance portion provided on an insulating substrate, a low resistance portion for applying a voltage to the high resistance portion, and the high resistance portion. And a phosphor layer deposited on the phosphor layer, and by applying a voltage to the low resistance portion, the phosphor layer is caused to emit light.

[0007]

It has been conventionally known that electron emission occurs when a current is applied to a film surface of a thin film having a small area formed on a substrate. This is generally called a surface conduction electron-emitting device. For example, MI Elinson (M.
I. There is a cold cathode device announced by Elinson et al. (Radio Engineering Electrophysics (Radio Eng. Electron.
Phys) Volume 10, 1290-1296, 1965.
Year).

The surface conduction electron-emitting device is a thin film made of highly conductive oxide, metal, semimetal, etc.
The Joule heat generated by this causes the thin film to be locally destroyed, deformed, or altered to have an electrically high resistance state. This treatment by heating by energization is called forming. In the surface conduction electron-emitting device, it is said that electrons are emitted by the island-shaped structure of the thin film formed by forming, but the mechanism of electron emission is not clear.

As a result of extensive studies by the present inventor on the structure and mechanism of the electron-emitting portion of the surface conduction electron-emitting device and its application to a display device, the details of the emission mechanism of the phosphor are unclear, but It was discovered that phosphor particles are deposited on a continuous high resistance portion and a phosphor is excited and emits light by applying a voltage to the high resistance portion. That is, the display element of the present invention forms a display pattern by applying fluorescent particles to the discontinuous high resistance portion which is the electron emission portion of the surface conduction electron-emitting device, and applies a voltage to the high resistance portion. By doing so, the phosphor is caused to emit light, and a display operation is performed.

As described above, according to the present invention, since the means for exciting the phosphor layer to emit light, that is, the discontinuous high resistance portion is formed inside the phosphor layer, the degree of freedom of the display pattern is increased, The emission brightness of the display section can also be made uniform.
Further, since the phosphor layer, the high resistance part and the main part for light emission of the low resistance part for voltage application are laminated or juxtaposed on the same substrate, the thinness of the envelope when housed in the envelope part. And weight reduction are possible.

[0011]

The present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view showing the basic structure of a display device according to the present invention. First, electrodes 2 and 3 made of a low resistance material for voltage application are provided at a minute interval on an insulating substrate 1 such as glass, and a discontinuous high resistance portion 5 in which fine particles 4 are dispersed is formed therebetween. ing. Then, the phosphor particles 6 are deposited on the high resistance portion 5 to form the phosphor layer 7. In order to prevent the phosphor layer 7 from being contaminated, the phosphor layer 7 emits light by putting the element in a vacuum and applying a voltage between the electrodes 2.3. It is preferable that the fine particles 4 forming the high resistance portion 5 have a particle size of several tens of angstroms to several μm, and the interval between the fine particles is in the range of several tens of angstroms to several μm. The distance between the electrodes 2.3 is usually 1.
The range from 00 angstrom to several tens of μm is suitable.

The material of the fine particles used in the present invention covers a very wide range, and almost all conductive materials such as ordinary metals, semimetals and semiconductors can be used. Among them, an ordinary cathode material having a low work function, a high melting point and a low vapor pressure, or a material having a large secondary electron emission coefficient is preferable.

As a method for forming the high resistance portion 5, a method called forming, in which electric current is applied to the conductive film through the voltage applying electrode 2.3 and the Joule heat generated locally destroys the film surface, the fine particles 4 are used. There are a method of forming dispersedly and a method of etching. In order to disperse the fine particles to form the high resistance portion 5, a dispersion liquid of fine particles of a desired material is applied onto the insulating substrate 1 by a method such as spin coating or dipping, and a solvent, a binder and the like are removed by heat treatment. The method is the simplest.

Dispersion of fine particles by coating and other specific manufacturing method of the display device according to the present invention will be described below. First, on an insulating substrate 1 such as clean glass or ceramics,
An Au film is deposited to a thickness of 1000 angstrom by the vacuum evaporation method, and the electrode 2.3 is formed by the photolithography method. The distance between the electrodes 2.3 is 100μ
m, and the width is 300 μm. Next, the fine particles 4 are applied between the electrodes 2.3. The fine particles are dispersed in an organic solvent composed of methyl ethyl ketone and cyclohexane, and this fine particle dispersion liquid is applied to the insulating substrate 1 formed on the electrode 2.3 by spin coating. And to evaporate the solvent, 2
Baking is performed at 50 ° C. for about 30 minutes. As a result, the fine particles 4 are dispersed and arranged on the insulating substrate 1, and the high resistance portion 5 is formed between the electrodes 2.3. Obviously, the fine particles 4 are
Although it is arranged on the entire surface of the insulating substrate 1, it does not cause any trouble because no electric current is applied to other than between the electrodes 2.3 when a voltage is applied. Finally, the phosphor particles 6 are formed on the high resistance portion 5 by the electrodeposition method.
Put it on. In the present invention, the zinc oxide phosphor is dispersed in an organic solvent consisting of ethyl alcohol, acetone and pure water, and an electrodeposition liquid obtained by adding a trace amount of additive thereto is used. The thickness of the phosphor layer 7 is controlled by the voltage applied during electrodeposition and the electrodeposition time.

The display device manufactured by the above steps is
By applying a voltage between the voltage applying electrodes 2.3,
The zinc oxide phosphor can emit blue-green light. In addition, a photolithography technique may be used to form the phosphors, and phosphors having different emission colors may be separately applied for color display.

2 (a) and 2 (b) are a schematic plan view and an enlarged view of an electrode portion showing an embodiment of the display device of the present invention. The same members as those shown in FIG. 1 are designated by the same reference numerals. As shown in FIGS. 2 (a) and 2 (b), a comb-shaped electrode 2.3 for voltage application is formed on an insulating substrate, and then a high resistance portion 5 composed of discontinuous fine particles 4 is formed on the entire surface of the insulating substrate. To form. Then, a phosphor layer 7 to be a display portion is laminated on the element, and a rectangular patterning is performed so as to cover the electrodes 2.3. The display pixel 8 formed in a rectangular shape in this way
By arranging in parallel with each other as shown in FIG. 3, it is possible to construct an arbitrary display pattern. Further, since the respective display pixels 8 can emit light under the same conditions, the light emission luminance can be made uniform at any place in the display pattern.

FIG. 4 is a schematic view showing another embodiment of the display device of the present invention. The configuration of a single display pixel is shown in FIG.
Since it is the same as the above-mentioned embodiment shown in FIG. As shown in the figure, the display pixels 8 are arranged in a matrix, and the two voltage applying electrodes are provided with signal busbars 9a-9.
f and the scanning buses 10a to 10f. As shown in FIG. 5, the signal busbars 9a to 9f and the scanning busbars 10a to 10f are formed by forming one of the busbars, and then forming the insulating layer 11 in a device shape except for the portion to be the display pixel 8. One bus bar may be provided. In order to turn on a desired pixel, it suffices to select the signal busbars 9a to 9f and the scanning busbars 10a to 10f that are tangential to the pixel and apply a voltage. It is possible to turn on the display pixels 8 arranged in a matrix suitable for such control of voltage application and perform various displays.

As described above, in the display element according to the present invention, the means for exciting the phosphor layer to emit light, that is, the discontinuous high resistance portion is formed inside the phosphor layer, so that the display pattern is free. As a result, the light emission brightness of the display section can be made uniform. Further, since the main elements for light emission of the phosphor layer, the high resistance part and the low resistance part for voltage application are stacked or arranged side by side on the same substrate, when housed inside the envelope, Can be made thinner and lighter.

[0019]

As described above, in the display device of the present invention, the means for exciting the phosphor layer to emit light, that is, the discontinuous high resistance portion is formed inside the phosphor layer, and the voltage applying electrode is the fluorescent material. Since it is formed on the same insulating substrate as the body layer and the high resistance portion, (a) there is no problem of non-uniformity of electron irradiation for exciting and emitting phosphor, and a display pattern can be freely formed, (b) display In any part of the pattern, the phosphor can be made to emit light under the same conditions, so that the emission brightness can be made uniform. (C) When housed inside the envelope,
This has the effect that the envelope can be made thinner and lighter.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view for explaining a basic configuration of the present invention.

FIG. 2 shows an embodiment of the present invention, (a) is a plan view,
(B) figure is an enlarged view of the electrode part of (a) figure.

FIG. 3 is a schematic top view showing a configuration of a display pattern by the display pixels shown in FIG.

FIG. 4 is a schematic top view showing the configuration of another embodiment of the present invention.

5 is an enlarged cross-sectional view around the display pixel shown in FIG.

FIG. 6 is a schematic cross-sectional view for explaining the structure of a fluorescent display tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating substrate 2,3 Electrode 4 Fine particle 5 High resistance part 6 Fluorescent substance particle 7 Fluorescent substance layer 8 Display pixel 9,9a-9f Signal busbar 10,10a-10f Scanning busbar 11 Insulating layer 12 Glass substrate 13 Filament 14 Grid

Claims (1)

[Claims] 1. A discontinuous high resistance portion provided on an insulating substrate, a low resistance portion for applying a voltage to the high resistance portion, and a phosphor layer deposited on the high resistance portion. And a voltage is applied to the low resistance portion to cause the phosphor layer to emit light.