JPH06203742A - Electron emitting element, electron beam generator and image forming device - Google Patents

Abstract

PURPOSE:To provide a surface conduction type electron emitting element used as an electron emitting source for an image forming device. CONSTITUTION:Fine grains 16 of forming an electron emitting part are dispersedly arranged between electrodes 12, 13 on a substrate 11. In this electron emitting element, a coating member 17 containing an element of atomic weight larger than an element, contained in the fine grain 16, is arranged in a surface of the fine grain 16, and further this coating member has a thickness of a mean free stroke or more of an electron passing through this member. In this way, an electron emitting amount and electron emitting efficiency are increased, and further uniformity and repeatability of each element are improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold cathode type electron-emitting device used as an electron-emitting source, an electron beam generator using the device, and an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, as a device which can emit electrons with a simple structure, for example, MI Elinson (M.
I. A cold cathode device announced by Elinson et al. Is known [Radio Engineering Electron Physics (Radio Eng.
on Phys. ) Volume 10, pp. 1290-1296,
1965].

This utilizes a phenomenon in which a thin film having a small area formed on a substrate causes electron emission by causing a current to flow in the film in parallel, and is generally called a surface conduction electron-emitting device. Has been.

As the surface conduction electron-emitting device, one using a SnO ₂ (Sb) thin film developed by Elinson et al., One using an Au thin film [G. Ditmer "Sin Solid Films" (G. Dittme
r: “Thin Solid Films”), vol. 3, 3
P. 17, (1972)], by ITO thin film [M. Hartwell and CG Fonds, M. Hartwell and CG Fons]
tad; “IEEE Trans.ED Con
f. ") 519, (1975)], by carbon thin film [Hiraki Araki et al .:" Vacuum ", Vol. 26, No. 1, 22.
P., (1983)] and the like are reported.

FIG. 6 shows a typical device configuration of these surface conduction electron-emitting devices. In the figure, 62 and 63
Is an electrode for obtaining electrical connection, 65 is a thin film formed of an electron emitting material, 61 is a substrate, and 66 is an electron emitting portion.

Conventionally, in these surface conduction electron-emitting devices, an electron-emitting portion is formed in advance by an electric heating process called forming before the electron emission. That is, by applying a voltage between the electrode 62 and the electrode 63, the thin film 65 is energized, and the Joule heat generated thereby locally destroys, deforms or deteriorates the thin film 65, and has an electrically high resistance. The electron emission function is obtained by forming the electron emission portion 66 in the state.

The electrically high resistance state means the thin film 65.
A discontinuous state film having a crack of 0.5 μm to 5 μm in a part thereof and having a so-called island structure inside the crack,
A spatially discontinuous and electrically continuous film is formed.

Conventionally, in the surface conduction electron-emitting device, a voltage is applied to the high resistance discontinuous film by electrodes 62 and 63, and a current is caused to flow on the surface of the device, so that electrons are emitted from the fine particles.

However, the above-described conventional electron-emitting device manufactured by the conventional forming process by electric heating has the following problems. (1) Since the discontinuous electron emission portion is formed through the processes of melting the thin film by heating, lowering the temperature due to termination of energization, and solidifying the melted thin film, the size and density of the island-shaped fine particles constituting the electron emitting portion, Structural design related to device characteristics such as arrangement and arrangement is virtually impossible, so it is difficult to improve devices and variations among devices are likely to occur. (2) Since the Joule heat generated in the forming step is large, it has a great influence on the substrate on which the element is formed, and depending on the material of the thin film forming the element, the substrate is likely to be broken, and it is difficult to perform multi-processing. (3) The material of the island is limited to gold, silver, SnO ₂ , ITO, etc., and a material having a small work function cannot be used, so that a large current cannot be obtained.

Due to the above problems, the surface conduction electron-emitting device has not been positively applied industrially, although it has the advantage that the device structure is simple. .

The present inventors have studied in view of the above problems, and as a result, have found that Japanese Patent Application Nos. 63-107570 and 63-11.
In 0480, a novel surface conduction electron-emitting device was proposed in which a fine particle film was placed between electrodes and an electron-emitting portion was provided by subjecting it to an electric current treatment. FIG. 7 shows a block diagram of this novel electron-emitting device.

In the figure, 72 and 73 are electrodes, and 75
Is a fine particle film, 76 is an electron emitting portion, and 71 is a substrate.

The characteristics of this electron-emitting device are as follows. (1) Since the electron emission portion 76 can be formed by passing a very small current through the fine particle film 75, an element without element deterioration can be formed, and the shape of the electrode can be arbitrarily designed. (2) Since the fine particles forming the fine particle film themselves serve as a component for emitting electrons, the material and shape of the fine particles can be designed, and the electron emission characteristics can be changed. (3) The selectivity of the materials of the substrate 71 and the electrodes, which are the constituent materials of the element, is expanded.

Further, conventionally, a thin image display device in which a plurality of planar electron-emitting devices and phosphor targets which respectively receive irradiation of electron beams emitted from the electron-emitting devices are opposed to each other. Exists. These electron beam display devices basically have the following structure.

FIG. 8 shows an outline of a conventional display device. In the figure, 81 is a substrate, 82 is a support, 83 is an element wiring electrode, 84 is an electron emission portion, 85 is an electron passage hole, 86 is a modulation electrode (grid electrode), 87 is a glass plate, and 88 is an image forming member. , For example, phosphors, resist materials, etc. emit light, discolor, charge when electrons collide,
It consists of members that change in quality. 89 is the bright spot of the phosphor.

Here, the electron emitting portion 84 is formed by a thin film technique and has a hollow structure that does not come into contact with the glass substrate 81. The element wiring electrode 83 may be formed of the same material as the electron emitting member or may be formed of a different material. Generally, one having a high melting point and a low electric resistance is used. The support body 82 is made of an insulating material or a conductive material.

In the electron beam display device, a voltage is applied to the element wiring electrode 83, electrons are emitted from the electron emitting portion having a hollow structure, and a voltage is applied to the modulation electrode 86 which modulates the electron flow according to the information signal. Electrons are taken out by applying, and the taken out electrons are accelerated to collide with the phosphor 88. Further, an XY matrix is formed by the element wiring electrodes 83 and the modulation electrodes 86, and an image is displayed on the phosphor 88 which is an image forming member.

[0018]

As described above, FIG.
In the conventional surface conduction electron-emitting device that requires the current-flowing heat treatment as shown in (1), it is difficult to improve the shape of the electron-emitting portion of the device and it is practically impossible to improve the device characteristics. Specifically, electron emission efficiency, emission current stability,
It was difficult to improve the basic characteristics of the electron-emitting device such as uniformity and reproducibility for each device. In addition, since the power required for heating by energization is large, the electron emitting portion and the substrate are significantly deteriorated, and it is practically impossible to apply to such an electron source in which a plurality of such elements are developed in a plane.

Further, when a conventional surface conduction electron-emitting device is applied as an electron source of the image display device as shown in FIG. 8, the emission brightness of the phosphor varies due to the difference in electron emission efficiency of each device, resulting in display unevenness. Was occurring.

That is, an object of the present invention is to provide an electron-emitting device capable of solving the above-mentioned problems, an electron beam generator using the device, and an image forming apparatus.

[0021]

Means and Actions for Solving the Problems In order to achieve the above-mentioned object, the means taken in the present invention is an electron-emitting device in which fine particles forming an electron-emitting portion are dispersedly arranged between electrodes on a substrate. In the above, the surface of the fine particles has a coating member containing an element having a larger atomic weight than the element contained in the fine particles and / or a low work function material, and the coating member has an electron beam passing through the coating member. It was decided to have a thickness not less than the mean free path.

Further, the electron beam generator of the present invention comprises a plurality of the electron-emitting devices of the present invention and a modulation means for modulating the electron beam emitted from the electron-emitting devices according to an information signal. did.

Further, in the image forming apparatus of the present invention, a plurality of the electron-emitting devices of the present invention, and a modulation means for modulating an electron beam emitted from the electron-emitting devices according to an information signal,
And an image forming member that forms an image by irradiation with the electron beam.

The components and operations of the present invention will be described in detail below.

FIG. 1 is a top view showing one embodiment of the electron-emitting device of the present invention, and FIG. 2 is a schematic partial cross-sectional view taken along the line AA of FIG.

In these figures, 11 is an element forming substrate, 12 and 13 are a pair of electrodes formed on the substrate 11,
14 is a minute gap between the electrodes 12 and 13, and 15 is the electrode 1.
2 and 13, a fine particle film dispersedly arranged, 16 is a fine particle made of the material of the fine particle film 15 and forming an electron emitting portion,
Reference numeral 17 is a covering member that covers the surface of the fine particles 16.

The element constituting substrate 11 used in the present invention is
Any material may be used as long as it has a substantially flat surface, but when a substrate made of a highly conductive material is used, the current flowing through the substrate increases when the device is driven, which is not preferable in terms of efficiency. . Therefore, it is desirable to use an insulating material, and specifically, ordinary glass, SiO ₂ thin film, silicon or the like is suitable.

Further, the electrodes 12 and 13 supply a voltage to the electron emitting portion, and any commonly used electrode material may be used. Furthermore, the minute electrode spacing portion 1
4 can be in the range of about 0.1 μm to 100 μm, but is preferably in the range of about 0.5 μm to 20 μm for practical use. The method for forming such an electrode is a conventional lithography,
Any method such as printing may be used.

The fine particle film 15 provided between the electrodes 12 and 13 forms an electron emitting portion by an electric current treatment or an electric current heat treatment in the electron-emitting device of the present invention, and the fine particles have a particle diameter of from several dozen to several tens. A conductive material of μm can be used. Specifically, LaB ₆ , C ₈ B ₆ , YB ₄ , and G
Borides such as dB ₄ , TiC, ZrC, HfC, Ta
Carbides such as C, SiC, WC, TiN, ZrN, HfN
Nitride such as Nb, Mo, Rh, Hf, Ta, W, R
e, Ir, Pt, Ti, Au, Ag, Cu, Cr, A
Examples thereof include metals such as 1, Co, Ni, Fe, Pb, Pd, Ca, and Ba, but are not limited to these. As a method for forming the above-mentioned fine particle film, a suitable method such as performing dispersion coating followed by baking to make fine particles, or forming by a gas deposition method may be used.
The sheet resistance of the fine particle film is 5 × 10 ³ to 1 × 10 ⁷ Ω /
□ A degree is desirable.

Next, the covering member attached to the surface of the fine particles, which is a feature of the present invention, will be described in detail.

The covering member 17 according to the present invention is shown in FIG.
As shown in (3), it is attached so as to cover the surface of the fine particles 16 forming the electron emitting portion. The covering member is a conductor,
Although any material such as a semiconductor or an insulator may be used, in the present invention, in particular, an element having a larger atomic weight than the element contained in the fine particles 16 constituting the electron emitting portion and / or a low work function material is used. What is included is used.

Specific examples of the material of the covering member include Ru, Pd, Ag, Cd, Sn, Sb, Te, Ta,
Examples thereof include metal materials such as W, Re, Pt, Au, Pb, Bi, Cs, and Ba, and compounds thereof. In the present invention, for example, when Pd fine particles are used for the electron emitting portion, the covering member may be formed of a material such as Pb or Pt having an atomic weight larger than Pd.

In the electron-emitting device of the present invention, as described above, the surface of the fine particles forming the electron-emitting portion is provided with a coating member made of a material containing an element having an atomic weight larger than that of the element forming the fine-particle material. Thereby, high electron emission efficiency can be obtained. In fact, it is unknown what role the coating member plays in improving the electron emission efficiency, but the present inventors have found that the coating member has an efficiency of refraction, diffraction, or scattering of electrons on the surface of the fine particles in the electron emission portion. I think that is improving. That is, the electrons accelerated in the fine particle film collide with the fine particles in the electron emission portion formed by the energization process, the energization heating process, etc., with the energy of the voltage applied from the outside, and are refracted, diffracted, or scattered. It is considered that, due to such effects, the orientation of the electron-emitting device is changed in a substantially vertical direction to escape to the outside of the device. Therefore, it is presumed that the electron emission efficiency is improved by forming the coating member using a material having an atomic weight larger than that of the fine particle material, that is, a material having a high electron density inside the atoms.

Further, the above-mentioned low work function material, for example, C
When a material such as s or Ba is used for the coating member, in addition to the effect of the coating member such as refraction, diffraction or scattering, the work function of the surface of the fine particles is lowered, so that a higher electron emission efficiency can be obtained.

In the present invention, the film thickness of the covering member is
It has a thickness equal to or larger than the mean free path of electrons passing through the covering member. As a result, the efficiency of refraction, diffraction, scattering, etc. of the electrons on the surface of the fine particles is further enhanced, the electron emission amount and the electron emission efficiency can be increased, and the time variation of the electron emission amount is reduced. It is possible to stabilize the emission current.

Generally, an electron moving inside a solid loses its kinetic energy by colliding with an atomic nucleus of an atom forming the solid, an electron, or the like. The distance traveled by the electron between the collisions, in other words, the distance that the electron moving inside the solid can travel without losing energy, is the mean free path of the electron.
h).

The mean free path of electrons does not depend so much on the kinds of atoms forming a solid but strongly on the energy of electrons, and the average of electrons having an energy of several eV to several thousand eV. The free path is approximately several Å to 100 Å. In particular, it is known that the mean free path takes a minimum value when the electron energy is about 100 eV. (G. Someriai, Chemistry i
n Two Dimensions: Surface
Cornell University Press,
Ithaca, N .; Therefore, the covering member used in the present invention uses a material having a larger atomic weight than the ultrafine particle material forming the electron emitting portion, and further, the mean free path determined by the energy of the electrons passing through the emitting portion. By having the above thickness, the electron emission efficiency can be improved.

As a method of measuring the mean free path of electrons,
X-ray photoelectron spectroscopy (XPS), which measures the kinetic energy of electrons that escape from the solid surface using X-rays as the excitation light source, ultraviolet photoelectron spectroscopy (UPS), which uses ultraviolet light as the excitation light source, and kinetic energy of Auger electrons excited by electron beams Auger electron spectroscopy (AES) and the like, which can directly measure the mean free path of electrons in the coating member used in the present invention.

Although the film thickness of the coating member varies depending on the drive voltage of the device, generally, several tens of Å to several hundred Å can be applied. In the present invention, the above-mentioned electron emission characteristics can be improved. Therefore, it is preferably 300 Å or more.

The covering member used in the present invention does not necessarily have to be a continuous film, and has a particle size of several tens of Å to several hundred Å.
Even a discontinuous film composed of the above fine particles has the same effect as above. Also in this case, the film thickness of the film portion forming the discontinuous film is equal to or larger than the mean free path, and more preferably, the particle diameter of the fine particles forming the covering member is equal to or larger than the mean free path. Is desirable.

The coating member may be formed by any method such as ordinary vacuum vapor deposition, coating and firing of an organic complex. In addition, as a procedure for forming the covering member, after forming the fine particle film 15,
Fine particles 16 which are formed immediately or subjected to electric current treatment
It does not matter whether the discontinuous electron emitting portion is formed, and then the discontinuous electron emitting portion is formed.

Further, by controlling the shape (width, length, etc.) of the region of the covering member that covers the surface of the discontinuous film portion composed of the fine particles 16, the effective shape of the electron emitting portion can be easily controlled. Therefore, the uniformity and reproducibility of the emission current for each device can be improved.

As described above, in the electron-emitting device according to the present invention, the electron emission amount and the electron emission efficiency are controlled without controlling the position, arrangement, etc. of the fine particles forming the electron-emitting portion formed by the energization process or the like. It is intended to improve the device characteristics such as the above, and thereby to provide an electron-emitting device having stable and reproducible and uniform device characteristics.

As described above, the present invention can be applied to a surface conduction electron-emitting device including electrodes facing each other and a discontinuous electron-emitting portion provided between the electrodes. It can be applied to both a so-called forming element that forms an electron emitting portion by heating by energization and a surface conduction electron emitting element in which a discontinuous film is previously provided between electrodes, and is particularly applicable to the latter element. In this case, electrons can be emitted by passing a very small current through the fine particle film, which is suitable for application to an electron source in which such an element is developed in a plurality of planes.

Furthermore, in the electron beam generator and the image forming apparatus using the planar electron source in which a plurality of electron-emitting devices of the present invention are arranged in a plane, the electron emission efficiency of each device is improved and at the same time, Since the element characteristics can be made uniform, it is possible to obtain an image display that can be driven at low power and has uniform emission brightness.

In the image forming apparatus of the present invention, as an image forming member for forming an image by irradiating an electron beam from the electron source, as in a conventional case, for example, a phosphor, a resist material, or the like is formed by collision of electrons. It is possible to use a member that emits light, changes color, charges, changes quality, etc. In particular, when a three-primary-color light emitter of red, green, and blue that emits light by irradiation of the electron beam is used, a color image can be displayed. .

[0047]

EXAMPLES Examples of the present invention will be described below.

Example 1 FIG. 1 is a structural diagram of an element of this example, and FIG. 2 is a line A- in FIG.
A sectional view and FIG. 3 are explanatory views showing the manufacturing method.

First, a method of manufacturing the electron-emitting device of this embodiment will be described with reference to these drawings.

.. A quartz substrate is used as the insulating substrate 11, sufficiently washed with an organic solvent or the like, and electrodes 12 and 13 are formed by a vacuum deposition technique or a photolithography technique. Any material may be used as the material of the electrode as long as it has conductivity, but in this embodiment, Ni is used.
It was formed using a metal. Practically, the electrode interval 14 is preferably 0.5 μm to 20 μm, and in this embodiment, the electrode interval 14 is 6 μm and the film thickness is 1000 Å (see FIG. 3A).

.. Next, organopalladium is applied to electrodes 12 and 1
3 is dispersed and applied. As the organic palladium, Okuno Pharmaceutical Co., Ltd. CCP-4230 was used.

A tape or a resist film is provided in a place where fine particles are not desired to be dispersed, and then organic palladium is applied by a dipping method or a spinner method. Next, the tape or the resist film was peeled off to form the fine particle film 15 at a predetermined position. Next, it is baked at 00 ° C. for 1 hour to disperse organic palladium to form a fine particle film in which palladium and palladium oxide are mixed. The width W of the fine particle film may be any value, but in this embodiment, it is set to 1 mm. At this time, the diameters of the fine particles of palladium and palladium oxide were both 10Å to 150Å, but the present invention is not limited to this (see FIG. 3 (b)).

.. The element thus obtained is set to 10 ⁻⁶ torr
It was placed in a vacuum container maintained at a vacuum degree of r to 10 ⁻⁷ torr, and an electron-emitting process was performed to form an electron emitting portion 16. When electron emission was performed, the voltage applied between the electrodes 12 and 13 was 14V. At that time, the current flowing through the element was approximately 5 mA, and the current emitted from the element was approximately 3 μA (see FIG. 3 (c)).

SEM observation of the electron-emitting portion of the thus-obtained electron-emitting device revealed that a discontinuous fine particle film having a particle size of about 50 to 100Å was formed. ． Next, an organic complex solution of platinum is dispersed and applied to the portion of the above element on which the palladium-containing fine particle film is to be formed.
Firing was performed at 0 ° C. for 10 minutes, and a covering member 17 made of platinum was provided to complete the device (see FIG. 3D).

SEM observation of the electron-emitting portion of the electron-emitting device thus obtained showed that the covering member was formed so as to cover the surface of the fine particle film, and the film thickness was about 3
It was 00Å.

In order to measure the mean free path of electrons in the coating member thus formed, UPS of a platinum film,
When the AES measurement was performed, the mean free path in platinum of electrons having an energy of an initial velocity of about 10 to 20 eV was about 100 to 150Å. The thickness of the platinum film formed on the surface of the electron emitting portion of the electron emitting device manufactured in this example was measured and found to be approximately 300.
It was confirmed to be Å.

Further, when the composition analysis of the electron emitting portion was carried out, palladium and platinum were detected, and it was confirmed from the intensity ratio thereof that platinum was the outermost surface of the emitting portion and palladium was the inside.

When the above device was put into a vacuum of 10 ⁻⁶ to 10 ⁻⁷ torr again and electrons were emitted at an applied voltage of 14 V, the device current was about 5 mA and the emission current was about 1.
It was 0 μA. In addition, when the stability of the emission current and the change with time were measured, the temporal fluctuation range of the emission current was approximately ± 3.
%, The increase / decrease in emission current after continuous driving for 100 hours was almost -5%.

On the other hand, in the case of an element using a fine particle film made of palladium in the electron emitting portion, the temporal fluctuation range of the emission current is about ± 7%, and by forming a coating member on the surface of the fine particle film, It was shown that the electron emission efficiency can be improved and the emission current can be stabilized at the same time.

Example 2 FIG. 4 is a structural diagram of an element of the present invention manufactured in this example.
In the figure, reference numeral 41 is an insulating glass substrate, 42 and 43 are a pair of electrodes facing each other, 44 is a discontinuous film made of fine particles forming an electron emitting portion, and 46 is a covering member which is a feature of the present invention. Although not shown in the figure, the fine particle film 44 is a discontinuous film after the energization process.

In this example, as in Example 1, a pair of electrodes 42 and 43 having an electrode interval of approximately 2 μm were formed on a glass substrate 41 that had been thoroughly degreased and washed, using ordinary photolithography and vacuum deposition techniques. . Next, an organic solvent containing an organometallic ruthenium complex was spin-coated between the electrodes, followed by baking at 450 ° C. for 10 minutes to form a fine particle discontinuous film composed of ruthenium and ruthenium oxide between the electrodes. Further, an organic solvent containing gold made of an organic metal was spin-coated on the above device, and then baked at 450 ° C. for 10 minutes to complete the device.

The device thus obtained was subjected to almost 2 × 10 ⁻⁶ t
After putting in a vacuum container maintained at a vacuum degree of orr and conducting energization, a DC voltage of 1k was applied to a position 5 mm above the element vertically.
When the device was driven by providing an anode electrode to which V was applied and the emission current was measured, a device current of 6 mA and an emission current of 15 μA were obtained when the device drive voltage was 14V. this is,
Compared with the case where ruthenium is used as the material of the emitting portion in a normal surface conduction type element, the amount of emitted current is about 5 times, and the element current is almost the same.
This means that the electron emission efficiency was doubled.

The morphology and composition of the electron emitting portion of the above-mentioned device were confirmed in the same manner as in Example 1, and it was confirmed that the fine particles forming the emitting portion were ruthenium fine particles coated with gold.

Further, it was confirmed that the film thickness of the covering member was about 300Å, and the mean free path of electrons having an energy of about 20 eV passing through the covering member was 150Å or more.

From the above results, it was confirmed that the present invention has the same effect as that of the first embodiment, even if the emission part material and the material to be the covering member are preliminarily laminated between the electrodes and then an electric current is applied.

Example 3 In this example, cesium which is a low work function material was used for the covering member according to the present invention. The device manufacturing method of this embodiment is the same as that of the first embodiment. The fine particle film forming the electron emitting portion was also formed by spin coating / baking of organometallic palladium as in Example 1.

In the present embodiment, the above device is used at 5 × 10 ^-8 to
After being placed in a vacuum of rr and subjected to energization to confirm the function and characteristics as an electron-emitting device, cesium was vapor-deposited in the same vacuum container.

As a result, the emission current before cesium vapor deposition was 1
The electron emission efficiency was less than μA and the electron emission efficiency was 0.1% or less, but the emission current after cesium vapor deposition was 20 μA or more, the electron emission efficiency was 1
It was over 0%, and both emission current and emission efficiency increased dramatically. This indicates that the work function of the surface of the fine particles is effectively reduced by vapor deposition of cesium as well as the efficiency of refraction, diffraction, scattering, etc. increased by the coating member.

The morphology and composition of the electron emitting portion of the above device were confirmed in the same manner as in Example 1. As a result, the fine particles forming the emitting portion were palladium fine particles coated with cesium. It was also confirmed that the film thickness of the covering member was about 300Å, and the mean free path of electrons passing through the covering member was 150Å or more.

Embodiment 4 FIG. 5 is a block diagram showing the image forming apparatus of this embodiment.
The planar electron source of the present embodiment is an array of a plurality of electron emitting devices of the first embodiment, and in particular, a plurality of linear electron sources in which electron emitting devices are arranged in parallel between an electrode 502 and an electrode 503 are provided on a plurality of substrates. It is provided regularly.

In the figure, 501 is an insulating substrate and 50
Reference numeral 5 is a fine particle film, 506 is an electron emitting portion, 507 is a grid electrode, 508 is an electron passage hole, and a planar electron source provided with a plurality of the above-mentioned electron sources and an electron beam emitted from the electron source are used as information. An electron beam generator is constituted by the grid electrode 507 which is modulated according to a signal.

Further, 509 is a metal back made of an aluminum material, 510 is a phosphor serving as an image forming member, 511 is a glass plate, and these constitute a face plate 513. In addition, 512 is a bright spot of the phosphor.

In this embodiment, the grid electrode 507 is composed of a plurality of line electrode groups and is arranged in the direction perpendicular to the electrode group of the planar electron source. The electron passage hole 508 is the electron emitting portion 5.
The grid electrode 507 is provided almost vertically above 06, and the XY matrix drive is performed using the grid electrode 507 as a signal electrode and the line electron source group as a scanning electrode to form an image.

The face plate 513 is a transparent glass plate 511 to which a phosphor 510 is uniformly applied, and a metal back 509 is further provided thereon.

In the image forming apparatus of this embodiment, the electrode 5
02 and the electrode 503 were applied with a voltage of 14 V to emit electrons from each electron emitting portion 506, and by applying an appropriate voltage to the grid electrode 507, the electrons were extracted and collided with the phosphor 510. It should be noted that the present image forming apparatus naturally has a vacuum degree of 1 × 10 ⁻⁵ torr to 1 × 10 ^5.
-It is placed under the environment of ^-7 torr, and the fluorescent substance is 500-500.
A voltage of 0V was applied.

An image forming apparatus of the present embodiment formed by using an electron-emitting device provided with a covering member which is a feature of the present invention,
As a result of comparative examination with a conventional image forming apparatus formed by using a similar electron-emitting device without a covering member, the following results were obtained. (1) In the image forming apparatus of the present embodiment, the amount of current emitted from each electron emitting portion is increased by 2 to 3 times compared with the conventional apparatus, and an extremely bright display image is obtained. (2) With the image forming apparatus of this embodiment, it is possible to obtain a good display image with less variation in brightness and less flicker in each emission bright spot. (3) Although the image forming apparatus of the present embodiment can obtain a brighter display image than the conventional apparatus, the power consumption is almost the same as that of the conventional apparatus.

From the above, the image forming apparatus using the electron-emitting device of the present invention can be suitably used for obtaining a color image and a high definition image.

Although the present embodiment has described only the image forming apparatus, the electron beam application apparatus includes various apparatuses such as a recording apparatus, a storage apparatus and an electron beam drawing apparatus. A device using a planar electron source in which a plurality of are arranged has the same effect.

[0079]

As described above, the electron-emitting device of the present invention in which the coating member is attached to the surface of the fine particles forming the electron-emitting portion, the electron beam generating device and the image forming apparatus configured by using the device are as follows. Produce the effect of. (1) The device characteristics such as the electron emission amount and the electron emission efficiency can be significantly improved without controlling the position, arrangement, etc. of the fine particles forming the electron emitting portion. (2) The temporal fluctuation (fluctuation) of the emission current can be reduced. (3) It is possible to provide a stable and reproducible electron-emitting device, and the electron beam generator having the devices spread in a plurality of planes can obtain a uniform electron emission amount. (4) As an image forming apparatus, an image display with uniform emission brightness can be obtained. (5) It is possible to reduce the power consumption of the image forming apparatus.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a surface conduction electron-emitting device of the present invention.

FIG. 2 is a schematic view of the AA cross section of FIG.

FIG. 3 is a process drawing for explaining the manufacturing process of the electron-emitting device of the present invention in Embodiment 1.

FIG. 4 is a schematic view of an electron-emitting device of the present invention manufactured in Example 2.

FIG. 5 is a configuration diagram of an image forming apparatus using the electron-emitting device of the present invention.

FIG. 6 is a configuration diagram of an electron-emitting device manufactured by conventional electric heating.

FIG. 7 is a configuration diagram of an electron-emitting device manufactured by subjecting a conventional fine particle film to electric conduction.

FIG. 8 is a configuration diagram of an image forming apparatus using a conventional electron source.

[Explanation of symbols]

 11 Element Forming Substrate 12, 13 Electrode 14 Electrode Spacing Part 15 Fine Particle Film 16 Fine Particles Forming Electron Emission Part 17 Covering Member

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Ichiro Nomura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hidetoshi Haru 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Yasuhiro Hamamoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (9)

[Claims] 1. In an electron-emitting device in which fine particles forming an electron-emitting portion are dispersedly arranged between electrodes on a substrate, the surface of the fine particles is coated with an element having an atomic weight larger than that of the elements contained in the fine particles. An electron-emitting device comprising a member, wherein the covering member has a thickness equal to or larger than a mean free path of electrons passing through the covering member. 2. An electron-emitting device in which fine particles forming an electron-emitting portion are dispersedly arranged between electrodes on a substrate, and a coating member containing a low work function material is provided on the surface of the fine particles, and the coating is provided. An electron-emitting device characterized in that the member has a thickness equal to or larger than the mean free path of electrons passing through the covering member. 3. The electron-emitting device according to claim 1, wherein the coating member has a thickness not less than the mean free path and not less than 300Å. 4. The electron-emitting device according to claim 1, wherein the covering member is made of a discontinuous film composed of fine particles. 5. The electron-emitting device according to claim 4, wherein the particle diameter of the fine particles forming the coating member is equal to or larger than the mean free path. 6. A plurality of electron-emitting devices according to any one of claims 1 to 5, and a modulation means for modulating an electron beam emitted from the electron-emitting devices according to an information signal. Electron beam generator. 7. A plurality of electron-emitting devices according to any one of claims 1 to 5, modulation means for modulating an electron beam emitted from the electron-emitting device according to an information signal, and irradiation with the electron beam. An image forming apparatus having an image forming member for forming an image. 8. The image forming member is a light-emitting body that emits light when irradiated with the electron beam.
The image forming apparatus described. 9. The image forming apparatus according to claim 7, wherein the image forming member is a three-primary-color light-emitting body of red, green, and blue that emits light when irradiated with the electron beam.