JP2916808B2 - Electron-emitting device, electron source, image forming apparatus, and manufacturing method thereof - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold-cathode type electron-emitting device, an electron source having a plurality of such devices, an image forming apparatus using the electron source, and a method of manufacturing the same. .

2. Description of the Related Art Conventionally, as a device capable of emitting electrons with a simple structure, for example, a cold cathode device disclosed by MI Elinson or the like is known [Radio Engineering Electron Physics] (Ra
dioEng. Electron Phys.) Volume 10, 1290-1296, 1965
Year].

This utilizes a phenomenon in which electrons are emitted when a current flows in a thin film having a small area formed on a substrate in parallel with the film, and is generally called a surface conduction electron-emitting device. .

Examples of the surface conduction electron-emitting device include a device using a SnO ₂ (Sb) thin film developed by Elinson et al., And Au.
By thin film [G. Dittmer: “Thin Solid Films”], 9
Vol.317, (1972)], using ITO thin film [M.
Hartwell & CJ Phonestud; "Iii Ei Trans" Edi Conference (M.
Hartwell and CGFonstad; “IEEE Trans.ED Conf.”) 5
19, (1975)], and those based on carbon thin films [Hisashi Araki et al .: "Vacuum" Vol. 26, No. 1, p. 22, (1983)].

FIG. 5 shows a typical device configuration of these surface conduction electron-emitting devices. In the figure, 93 and 94 are electrodes for obtaining electrical connection, 90 is a thin film formed of an electron emitting material, 91 is a substrate, and 96 is an electron emitting portion.

Conventionally, in these surface conduction electron-emitting devices,
Before electron emission, an electron emission portion is formed in advance by an energization process called forming. That is, by applying a voltage between the electrode 93 and the electrode 94, a current is applied to the thin film 90, and the thin film 90 is locally destroyed, deformed or deteriorated by Joule heat generated thereby, and has a high electrical resistance. An electron emitting function is obtained by forming the electron emitting portion 96 in the state.

Note that the electrically high resistance state means that a part of the thin film 90 has a thickness of 0.
A discontinuous film having a crack of 5 μm to 5 μm and having a so-called island structure inside the crack. The island structure generally means fine particles having a diameter of several tens to several μm on the substrate 91, and each fine particle has a spatially discontinuous and electrically continuous film thickness.

Conventionally, a surface conduction electron-emitting device emits electrons from the fine particles by applying a voltage to the high-resistance discontinuous film through the electrodes 93 and 94 and flowing a current through the surface of the device.

However, the electron-emitting device manufactured by the above-described conventional energizing forming process has the following problems.

1) Because it is not possible to design an island structure that will be the electron emission part,
It is difficult to improve the elements, and the balance between the elements is likely to occur.

2) Since the Joule heat generated during the forming process is large, the substrate is easily broken and it is difficult to form a multi-layer.

3) The material of the island is limited to gold, silver, SnO ₂ , ITO and the like, and a material having a small work function cannot be used, so that a large current cannot be obtained.

Due to the above-described problems, the surface conduction electron-emitting device has not been actively used in industry, despite the advantage that the device structure is simple.

The present inventors have studied in view of the above problems, and as a result, in Japanese Patent Application Nos. 63-107570 and 63-110480, a fine particle film is arranged between the electrodes, and the electron emission is performed by applying a current to the fine particle film. A new surface-conduction electron-emitting device with a section is proposed. FIG. 6 shows the configuration of this new electron-emitting device.

In the figure, 104 and 103 are electrodes, 105 is a fine particle film, 106
Denotes an electron emitting portion, and 101 denotes a substrate.

The features of this electron-emitting device include the following.

1) Since an electron emission portion 106 can be formed by applying a very small amount of current to the fine particle film 105, 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 are constituents of the electron emission, the material and shape of the fine particles can be designed, and the electron emission characteristics can be changed.

3) The selectivity of the material of the substrate 101 and the electrode, which are the components of the element, is expanded.

[Problems to be Solved by the Invention] However, in the surface conduction electron-emitting device proposed by the above-mentioned inventors, the electron-emitting portion 106 is formed in the fine particle film 105 between the electrodes as shown in FIG. The electron emission portion 106 is located at an electron emission position.
The electron emitting portion 106 is formed from a fine range of 0.01 μm to 0.5 μm, and its position varies depending on the conditions for forming the fine particle film, the condition of the energizing process, and the like, and is accurately arranged at a predetermined position between the electrodes. It was difficult to do.

In FIG. 6, the electron-emitting portion is drawn linearly, but actually it is meandering considerably between the electrodes 104 and 103, and its form changes considerably depending on the energization conditions. Length could not be designed.

Generally, the interval between the electrode 103 and the electrode 104 is 0.5 μm to 50 μm
However, it was more difficult to control the position of the electron-emitting portion as the distance between the electrodes became wider.

Such a variation in the position of the electron-emitting portion causes a variation in the amount of electron emission when applied as an electron-emitting device. Particularly, when the device is applied as a planar electron source in which a plurality of these devices are arranged, the electron emission varies depending on the location. There was a problem that the amount of release changed.

As an effective application of the planar electron source, as disclosed in JP-A-56-28445, an electron source having a plurality of electron-emitting devices developed in a planar shape and irradiating an electron beam from the electron source are disclosed. There is a thin image forming apparatus in which a phosphor target to be received is made to correspond to each other. However, when the above-mentioned surface conduction electron-emitting devices are applied as an electron source of this image forming apparatus, the electron emission amount of each element is different. The fluorescent brightness of the phosphor differs depending on the location, and display unevenness occurs.

In the conventional electron-emitting device as shown in FIG. 5, the power required for forming is large, so that the electron-emitting portion and the substrate are significantly deteriorated, and the electron-emitting characteristics and the position of the electron-emitting portion must be controlled. Was impossible.

That is, an object of the present invention is to provide an electron-emitting device which can solve the above-mentioned problems, an electron source having a plurality of the electron-emitting devices, an image forming apparatus having the electron source, and a method of manufacturing the same. It is in.

[Means and Actions for Solving the Problems] The configuration of the present invention achieved to achieve the above object is as follows.

That is, the first aspect of the present invention has a stepped portion formed by a heating member that generates heat by energization on an insulating substrate, and is connected to a pair of electrodes across the stepped portion and is directly in contact with the heating member. An electron-emitting device is characterized in that an electron-emitting portion is formed near the step of the film.

A second aspect of the present invention is the method for manufacturing an electron-emitting device according to the first aspect of the present invention, wherein when forming an electron-emitting portion on the fine particle film, a current is applied to the fine particle film via the pair of electrodes. And a heat treatment for energizing the heat-generating member.

According to a third aspect of the present invention, there is provided an electron source comprising a plurality of the first electron-emitting devices according to the first aspect of the present invention.

A fourth aspect of the present invention resides in a method for manufacturing an electron source, wherein a plurality of electron-emitting devices are manufactured by the second method of the present invention when manufacturing the third electron source of the present invention.

According to a fifth aspect of the present invention, there is provided an image forming apparatus comprising: the third electron source of the present invention; and an image forming member that forms an image by irradiating electrons emitted from the electron source.

According to a sixth aspect of the present invention, there is provided a method for manufacturing an image forming apparatus according to the fifth aspect of the present invention, wherein an electron source is manufactured by the fourth method of the present invention when manufacturing the fifth image forming apparatus of the present invention.

According to the present invention, it is possible to control the temperature at the time of forming the electron-emitting portion by using the heat-generating member provided directly under the fine particle film, and to form the electron-emitting portion near the step of the heat-generating member. It is possible to improve the reproducibility of the shape and the position of the electron-emitting portion.

 Hereinafter, components and operations of the present invention will be described in detail.

Examples of the fine particle film in the present invention include a film of conductive fine particles having a particle size of tens to several μm to several μm, or a carbon thin film in which these conductive fine particles are dispersed. The material may be used Pd, Ag, Au, a metal such as Ti, PdO, oxides of SnO ₂ such as conductor or the like, which one be a conductive material. These films are formed between the electrodes by a gas deposition method, a dispersion coating method, or the like.

FIG. 1 is an element configuration diagram showing one embodiment of the present invention. In the figure, 11 is an insulating substrate, 12 is a heating member having a step portion for defining the position of the electron emitting portion (hereinafter, referred to as a heating member).
This will be referred to as “electron emission portion defining member”. ), 13 and 14 are electrodes, 15
Denotes a fine particle film, and 16 denotes an electron emitting portion.

As shown in FIGS. 1 and 3, the electron-emitting device of the present invention has fine particle films 15, 45 that straddle the electron-emitting portion defining members 12, 42 and are in direct contact with the electron-emitting portion defining members. An electron emitting portion is formed in the vicinity of the step due to the above. The thickness in the shape of the stepped portion depends on the type of the material of the heat generating member and the structure of the electron emitting portion defining member, but is usually preferably about one hundred and several tens to several μm, and generally 0.1 μm to 1 μm is practical. In addition, it is desirable that the width of the step is narrower than the distance between the electrodes forming the electron-emitting portion.
1/2 or less is practical. Further, the heat generating member may generate heat when energized, and any material may be used as long as there is a conductive material, and a material whose heat generation temperature increases by several tens to several hundred degrees is preferable. Further, the interval between the electrodes 13 and 14 is preferably 0.1 μm to 100 μm, and generally 0.5 μm to 10 μm is practical.

When conducting the fine particle film 15 provided in the step portion made of the electron emission portion defining member as described above, after applying a current to the heating member of the electron emission portion defining member and locally heating the same, the current application process is performed. Alternatively, when the energizing process is applied to the fine particle film 15 while energizing the heating member simultaneously with the energizing process and locally heating, the electron emitting portions 16 along the step of the electron emitting portion defining member 12 as shown in FIG. Are formed in a straight line, and the electron emitting portion does not meander as in the above-described conventional example.

Depending on the temperature of the electron emitting portion defining member, the type of the particulate material, the type, thickness, width, etc. of the electron emitting portion defining member, the electron emitting portion may be located above or below the electron emitting portion defining member. Alternatively, it can be formed on either of the side surfaces.

Of course, if the step portion is a curve, the electron emission portion is formed in a curve along the step.

The method of energization treatment is to form an electron emission portion by increasing the resistance by applying a current to the fine particle film, or to form an electron emission portion by lowering a portion of the resistance by applying a current to the fine particle film. However, any of them may be used.

During the energization process, the structure of the fine particle film changes, and the above-described discontinuous electron-emitting portion is formed.

At this time, by applying a current to the electron emission portion defining member composed of the heating member and heating the fine particle film, the controllability at the time of forming the electron emission portion is improved, and the electron emission portion is located near the step of the electron emission portion defining member. Can be formed. It is unclear what role these steps play in the structural change of the fine particle film. However, the present inventors have found that the electric field distribution becomes discontinuous in the vicinity of the steps during the energization treatment because the temperature distribution becomes discontinuous. Are assumed to be discontinuous, and as a result, an electron-emitting portion is formed along the step. Therefore, it is expected that the same effect can be obtained by providing a member in which the temperature and the electric field are discontinuous, in addition to the provision of the electron emission portion defining member having a step portion between the electrodes and formed of a heating member.

In the electron-emitting device of the present invention, the shape of the electron-emitting portion defining member is not particularly limited, and may be any shape such as a rectangular cross-section as shown in FIG. 1 and a triangular cross-section as shown in FIG. It can be formed in a cross-sectional shape.

As described above, when forming the electron-emitting portion in the fine particle film, by performing the energizing process for supplying current to the fine particle film and the heating process for supplying current to the electron-emitting portion defining member, the electron emission portion is compared with the conventional example. Since the shape and position of the emission element can be accurately designed, not only can the electron emission characteristics be controlled, but also the reproducibility of the element can be obtained.

In the above-described image forming apparatus provided with a plurality of electron-emitting devices, if the electron-emitting devices of the present invention are used, the electron emission amount of each device is equal, and a good image without display unevenness is formed.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 FIG. 1 is an element configuration diagram of this example, and FIG. 2 is an explanatory diagram showing a manufacturing method thereof.

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

A quartz substrate is used as the insulating substrate 21 and sufficiently washed with an organic solvent or the like, and electrodes 23 and 24 are formed by a vacuum deposition technique and a photolithography technique. The electrode may be made of any material as long as it has conductivity. In this embodiment, the electrode is made of Ni metal. It is desirable that the electrode interval is practically 0.5 μm to 20 μm. In this embodiment, the electrode interval is 6 μm and the film thickness is 1000 °.

Next, the electron emission portion defining member 22 is formed by a vacuum deposition technique and a photolithography technique in the same manner as described above. The member may be any material as long as it generates heat when energized. In this example, Ni-Cr metal was used, and the width of the member was 2 μm and the film thickness was 2000 mm.

Next, organic palladium is dispersed and applied between the electrodes 23 and 24. As organic palladium, Okuno Pharmaceutical Co., Ltd. CCP-4230 was used.

A tape or a resist film is provided where no fine particles are 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 25 at a predetermined position. Next, baking is performed at 300 ° C. for 1 hour to disperse the organic palladium, thereby forming a fine particle film in which palladium and palladium oxide are mixed. Although the width W of the fine particle film may be any value, it is set to 1 mm in this embodiment. At this time, the diameters of the fine particles of palladium and palladium oxide were both 10 ° to 150 °, but the present invention is not limited to this.

Next, electricity is supplied to the electron emitting portion defining member 22 to generate heat, and when the temperature of the surface of the member 22 reaches about 50 ° C., the supply of electricity is stopped, and immediately thereafter, the electrode 23 is turned to the negative side and the electrode 24 is turned to the positive side. As described above, and the fine particle film 25 was energized. As a result, as shown in FIG. 2, an electron emitting portion 26 was formed along the electron emitting portion defining member 22.

Here, the thickness of the fine particle film before the energization treatment is several tens of
Å is practical but not limited to this. The sheet resistance of the fine particle film at this time is about 10 ³ to 10 ⁸ Ω / □.

The thickness of the fine particle film is considered to be substantially uniform between the electrodes including the electron emission portion defining member 22.

In the present embodiment, the direction in which the current flows in the energization processing is from the electrode 24 side to the electrode 23 side. However, in the present embodiment, the electron emission portion can be formed at the above-described position with good reproducibility regardless of the current flowing direction.

When the electron-emitting device of this example was compared with a conventional electron-emitting device without the electron-emitting portion defining member 12, substantially the same values were obtained in the amount of emitted electrons and the efficiency of electron emission. Next, comparing the shapes of the electron-emitting portions, the conventional device
Despite the large meandering over the width of 1 mm, the electron-emitting device of this example was able to form the electron-emitting portion almost linearly along the electron-emitting portion defining member. The fact that the position of the electron-emitting portion can be set accurately has a very important meaning in consideration of applications. For example, in deflecting and modulating the electrons emitted from the element, it is necessary that the position of the electron-emitting portion be accurately arranged in order to perform accurate control. Therefore, the element of this embodiment provides a very effective element practically.

Further, by changing the position of the electron emission portion defining member, the electron emission portion can be easily changed accordingly. The electron-emitting device of this embodiment is to provide a surface-conduction electron-emitting device whose position can be designed.

Embodiment 2 FIG. 4 is a configuration diagram showing an image forming apparatus of the present embodiment. The planar electron source of this embodiment is obtained by arranging a plurality of the electron-emitting devices of the first embodiment. In particular, a plurality of line electron sources in which the electron-emitting devices are arranged in parallel between the electrodes 83 and 84 are regularly arranged on a substrate. It is provided.

In the figure, 89 is a grid electrode, 810 is an electron passage hole, 8
13 is a glass plate, 812 is a phosphor, 811 is a metal back made of an aluminum material, 815 is a face plate, and 814 is a luminescent spot of the phosphor.

In the present embodiment, the grid electrode 89 is composed of a plurality of line electrode groups, and is arranged in a direction perpendicular to the electrode group of the planar electron source. The electron passage hole 810 is provided substantially vertically above the electron emission section 86, and forms an image by performing XY matrix driving using the grid electrode 89 as a signal electrode and the line electron source group as a scanning electrode.

The face plate 815 has a phosphor 812 uniformly coated on a transparent glass plate 813, and a metal back 8
11 is provided.

In the image forming apparatus of the present embodiment, the electrodes 83 and 84
Electrons were emitted from each electron emitting portion 86 by applying a voltage of 14 V, and electrons were extracted by applying an appropriate voltage to the grid electrode 89 to collide with the phosphor 814. This image forming apparatus naturally has a vacuum degree of 1 × 10 ⁻⁵ Torr.
~ 1 × 10 ^-7 Torr environment, 500-5000V for phosphor
Was applied.

In the present embodiment, the following results were obtained by comparison with an image forming apparatus using an electron source without the electron emission portion defining member 82.

(1) In the present embodiment, a display screen with uniform brightness was obtained because the amount of electrons emitted from each electron emitting portion was equal.

(2) In the present embodiment, the positions of the electron-emitting portions are accurately determined, so that the luminescent spots on the phosphor have substantially the same shape and are regularly arranged.

On the other hand, in the image forming apparatus using the electron source without the electron emission portion defining member, the shape of the bright spot and the pitch of the bright spot differ depending on the location.

For this reason, this embodiment is effective for obtaining a color image and a high-definition image.

As described above, the present embodiment has been described only with respect to the image forming apparatus. However, as the image forming member, in addition to the phosphor, all members whose states change due to the collision of an electron beam such as a resist material or a thin film metal are used. The electron beam application device includes various devices such as a recording device, a storage device, and an electron beam drawing device. The present invention relates to an image forming device using a planar electron source having a plurality of electron-emitting devices. If they have the same effect.

[Effects of the Invention] As described above, according to the present invention, it is possible to perform temperature control when forming an electron-emitting portion by using a heat-generating member provided directly below a fine particle film, and An electron emitting portion can be formed in the vicinity of the step portion of the heat generating member, and the reproducibility of the shape and position of the electron emitting portion can be improved.

(1) In addition to controlling the electron emission characteristics such as the amount of electron emission and the electron emission efficiency, it has become possible to manufacture devices with little variation in characteristics between devices.

(2) An image display with uniform light emission luminance can be obtained as an image forming apparatus.

(3) Since the position of the electron-emitting portion is accurately determined, an image display having a uniform luminescent spot shape of the phosphor can be obtained as an image forming apparatus.

(4) Since the position of the electron emission portion is accurately determined, there is an effect that the shape design and control system of the modulation electrode are simplified as an image forming apparatus.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an electron-emitting device according to Embodiment 1 of the present invention. FIG. 2 is a process chart showing a method for manufacturing an electron-emitting device according to the first embodiment of the present invention. FIG. 3 is an explanatory view showing another embodiment of the present invention. FIG. 4 is an explanatory diagram of an image forming apparatus according to the second embodiment. FIG. 5 is a configuration diagram of a conventional electron-emitting device formed by electric heating. FIG. 6 is a configuration diagram of a conventional electron-emitting device formed by applying a current to a thin-film conductor including fine particles or a fine-particle film. 11, 21, 41, 71, 81, 91, 101 ... insulating substrate 12, 22, 42, 72, 82 ... electron emission portion defining member (heating member) 13, 14, 23, 24, 43, 44, 73, 74, 83, 84, 93, 94, 10
3, 104 ... electrodes 15, 25, 45, 75, 85, 105 ... fine particle film 16, 26, 76, 86, 96, 106 ... electron emission part

Continued on the front page (72) Inventor Tetsuya Kaneko 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Haruhito 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hidetoshi Suzumi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-2-92638 (JP, A) (58) Fields investigated (Int. . ⁶ , DB name) H01J 1 / 30,9 / 02 H01J 29 / 04,31 / 12

Claims (6)

(57) [Claims] 1. A fine particle film having a stepped portion formed by a heat generating member which generates heat by energization on an insulating substrate, connected to a pair of electrodes across the stepped portion, and directly contacting the heat generating member. An electron-emitting device having an electron-emitting portion formed near a step. 2. The method for manufacturing an electron-emitting device according to claim 1, wherein an electron-emitting portion is formed in said fine particle film.
A method of manufacturing an electron-emitting device, comprising: applying an electric current to the fine particle film through the pair of electrodes; and performing a heat treatment to apply an electric current to the heating member. 3. An electron source comprising a plurality of electron-emitting devices according to claim 1 arranged on an insulating substrate. 4. When manufacturing the electron source according to claim 3,
A method for manufacturing an electron source, comprising: manufacturing a plurality of electron-emitting devices by the method according to claim 2. 5. An image forming apparatus comprising: the electron source according to claim 3; and an image forming member that forms an image by irradiation of electrons emitted from the electron source. 6. A method for manufacturing an image forming apparatus according to claim 5, wherein the electron source is manufactured by the method according to claim 4 when manufacturing the image forming apparatus according to claim 5.