JP2748128B2 - Electron beam generator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an electron beam generator including an electron-emitting device provided on an insulating substrate.

[Prior art] Conventionally, as an element which can obtain electron emission with a simple structure, for example, MIElinson
And the like are known. [Radio Engineering Electron Phys., Vol. 10, pp. 1290-1296,
1965] This utilizes the phenomenon that electron emission occurs when a current flows through a small-area thin film formed on an insulating substrate in parallel with the film surface, and is generally called a surface conduction electron-emitting device. Have been.

Examples of the surface conduction electron-emitting device include a device using a SnO ₂ (Sb) thin film developed by Ellison et al. And a device using an Au thin film [G. Dittmer: “Thin Solid Films”. "), Volume 9, 317
Page, (1972)], using ITO thin film [M. Hartwell and C.G.Fonstad “IIE Transformer”
Hartwell and CGFonstad: “IEEE Trans.ED Conf.”) 5
19, (1975)], and those using a carbon thin film [Hisashi Araki et al .: "Vacuum", Vol. 26, No. 1, p. 22, (1983)].

These surface conduction electron-emitting devices are: 1) high electron emission efficiency is obtained; 2) the structure is simple; therefore, manufacture is easy; 3) many devices can be arrayed on the same substrate; 4) response speed. It has advantages such as high speed, and has the potential to be widely applied in the future.

[Problems to be Solved by the Invention] However, in the case of the conventional electron-emitting device, the potential of the insulating substrate on which the electron-emitting device is formed is unstable, so that the trajectory of the emitted electron beam becomes unstable. Had a problem.

In order to solve this problem, the present inventors have proposed a method of coating the surface of an insulating substrate around an electron-emitting device with a material having high conductivity to stabilize the potential on the substrate surface.

This method stabilizes the electron beam trajectory, but there is a point to be improved in terms of reduction of power consumption.

In other words, the high-conductivity material covering the gap between the positive electrode and the negative electrode of the electron-emitting device and the high-conductivity material covering the peripheral portion of the electron-emitting device should have the same composition to prevent contamination of the electron-emitting portion and to reduce the manufacturing process. This is advantageous in terms of simplification. However, if the coating is performed so as to maximize the emission efficiency and output current of the electron-emitting device, the area around the electron-emitting device greatly exceeds the coating density required to stabilize the surface potential of the substrate.
The current tended to flow more than necessary. For this reason, when applied to an electron beam generator having a large number of electron-emitting devices, power consumption has been increased.

[Means for Solving the Problems (and Action)] The present invention has been made to solve the above-mentioned problems, and has a high conductivity around the electron emitting portion with respect to the electron emitting portion (inter-electrode region). By changing the coating material of the material, the power consumption for stabilizing the electron beam trajectory is reduced without deteriorating the performance of the electron-emitting device.

That is, the present invention provides an electron beam generating apparatus including an electron-emitting device having an electron-emitting portion between electrodes on an insulating substrate surface, wherein an electric resistance of at least 1 × 10 First in the range of ⁸ to 1 × 10 ¹⁰ Ω / □
Having an electric resistance of 1 × in the inter-electrode region.
The present invention relates to an electron beam generator having a second conductive film including an electron emission portion in a range of 10 ⁴ to 1 × 10 ⁷ Ω / □.

The electron beam generating apparatus according to the present invention further has a feature that the first and second conductive films are mainly formed of the same material, and the first and second conductive films are The first and second conductive films are conductive films having different particle densities, and the electron-emitting device is a surface conduction electron-emitting device. Is also included.

Embodiment FIGS. 1 to 4 are plan views for explaining a first embodiment of the present invention. FIG. 1 shows the dimensions of the element, and FIGS. FIG. 4 shows the progress and the completed form.

In FIG. 1, reference numeral 1 denotes an insulating substrate made of glass, ceramic, or the like, on which a positive electrode 2 and a negative electrode 3 are provided. 2, 3 can be easily formed by a conventionally known vacuum deposition method and a photolithographic etching method or a lift-off method, or a printing method, and the electrode material is a general conductive material, in addition to metals such as Au, Pt, and Ag, Oxide conductive materials such as SnO ₂ and ITO can also be used.

The thickness of the electrodes 2 and 3 is suitably about several hundreds to several micrometers, but is not limited to this value. Further, the dimension of the electrode gap G is appropriately from several hundred degrees to several tens of μm, and the interval width W is suitably from several μm to several μm. However, it is not limited to this dimension value.

By covering a W × G region sandwiched between the positive electrode 2 and the negative electrode 3 with a highly conductive material so as to have a surface resistance of about 1 × 10 ⁴ to 1 × 10 ⁷ Ω / □ as described later, An electron emission portion is formed in this region. The surface of the substrate excluding the region of W × G is coated with a high-conductivity material so as to be about 1 × 10 ⁸ to 1 × 10 ¹⁰ Ω / □. Hereinafter, the procedure will be described.

FIG. 2 shows a structure in which a photoresist pattern 4 is formed on the substrate shown in FIG. 1, and a window is formed in the W × G region. If there is no displacement at all, the size of this window may be equal to W × G. However, in this embodiment, the size is slightly increased to facilitate manufacture.

Next, the substrate of FIG. 2 is coated with a material having higher conductivity than the substrate. Here, the coating does not necessarily mean a state in which the entire surface is covered, but refers to a state in which fine particles of a high conductivity material are dispersed and arranged at appropriate intervals.

Specifically, the coating is performed using, for example, a dispersion of fine particles of a high conductivity material. For example, fine particles and an additive for promoting the dispersion of the fine particles are added to an organic solvent such as an alcohol, and the dispersion of the fine particles is adjusted by stirring or the like. After coating or spraying the fine particle dispersion, or dipping the substrate into the fine particle dispersion, the temperature at which the solvent or the like evaporates is maintained at, for example, 140 ° C. for about 10 minutes, so that the high-conductivity material is provided at appropriate intervals. Distributed.

The material of the fine particles used here is in a very wide range, and almost all of conductive materials such as ordinary metals, metalloids and semiconductors can be used. Among them, those having a low work function, a high melting point and a low vapor pressure are preferred. Specifically, borides such as LaB ₆ , CeB ₆ , YB ₄ , GdB ₄ and the like, TiC, ZrC, Hf
Carbides such as C, TaC, SiC, WC, etc., nitrides such as TiN, ZrN, HfN, Nd, Mo, Rh, Hf, Ta, W, Re, Ir, Pt, Ti, Au, Ag, Cu, Cr, Al , C
o, Ni, Fe, Pb, Pd, Cs, metals such as Ba, In ₂ O _3, metal oxides such as _{SnO 2, Sb 2 O 3,} Si, a semiconductor such as Ge, carbon, Ag, Mg
And the like.

The arrangement density of the fine particles can be controlled by the preparation of the fine particle dispersion and the number of application times. Then, after applying (or dipping) an appropriate number of times, the photoresist pattern is lifted off to obtain the state shown in FIG. In this state, the positive electrode 2 and the negative electrode 3
Has a surface resistance greater than the target of 1 × 10 ⁴ to 1 × 10 ⁷ Ω / □.

Next, a high conductivity material is coated on the entire surface of the substrate of FIG. 3 by coating or dipping in the same manner as performed on the substrate of FIG. After an appropriate number of coatings (or dippings), the configuration shown in FIG. 4 is completed. In the figure, near the gap between the positive electrode 2 and the negative electrode 3, fine particles of a high conductivity material are dispersed and arranged with a high density, so that they have a surface resistance of 1 × 10 ⁴ to 1 × 10 ⁷ Ω / □, Further, since the peripheral portion is dispersed and arranged with a relatively low density, it has a surface resistance of 1 × 10 ⁸ to 1 × 10 ¹⁰ Ω / □.

As a result, an electron beam of 2 μA is emitted from the electron-emitting device, the trajectory of the beam becomes extremely stable, and the power consumed for stabilizing the surface potential of the insulating substrate is the same as that of the conventional device. Was reduced to 1/10 to 1/200 compared to the case of

In the present embodiment, since the window of the resist pattern is made larger than W × G in the step of FIG. 2, the region covered with high density slightly protrudes from the gap between the positive electrode and the negative electrode. However, this did not degrade the emission current amount or emission efficiency of the electron-emitting device.

The surfaces of the positive electrode 2 and the negative electrode 3 are also coated with a high conductivity material, but this does not cause any problem.

Note that the embodiment of the present invention is not necessarily limited to the embodiment shown in FIG. Since the electron beam trajectory mainly affects the substrate potential in the vicinity of the electron-emitting portion, it is not always necessary to cover the entire surface of the substrate with a high-conductivity material as shown in FIG. The form as shown in the figure may be used. In the figure, 5 and 7 are 1 × 10 ⁴ -1 × 1
A part having a surface resistance of 0 ⁷ Ω / □ (second conductive film)
Here, 6 and 8 are portions (first conductive films) having a surface resistance of 1 × 10 ⁸ to 1 × 10 ¹⁰ Ω / □. This embodiment can reduce power consumption more than the embodiment of FIG.

Further, the manufacturing method is not limited to the steps described with reference to FIGS. 1 to 4, for example, as shown in FIG.
The entire surface of the substrate on which the electrodes 2 and 3 are formed is previously
^A highly conductive material is coated so as to have a surface resistance of about ⁸ to 1 × 10 ¹⁰ Ω / □, and then a photoresist pattern is formed as shown in FIG. The photoresist pattern may be removed by coating with a high-conductivity material until it becomes about 1 × 10 ⁴ to 1 × 10 ⁷ Ω / □.

Alternatively, the entire substrate on which the electrodes are formed is
A high conductivity material is coated to about × 10 ⁴ to 1 × 10 ⁷ Ω / □ (resistance of the surface of the insulating substrate), and then a photoresist pattern as shown by a hatched portion 10 in FIG. 9 is formed. Then, etching is performed using an etching solution that dissolves the high conductivity material until the surface resistance of the exposed portion becomes 1 × 10 ⁸ to 1 × 10 ¹⁰ Ω / □. After that, if you remove the photoresist pattern,
Although the configuration shown in FIG. 10 is obtained, this embodiment also achieved almost the same performance as that of FIG.

Alternatively, other than photoresist, as shown below,
A process using a water-soluble material (such as polyvinyl alcohol or gelatin) is also possible.

That is, first, the resist pattern as shown in FIG.
After the formation of 11, a water-soluble material such as polyvinyl alcohol or gelatin is applied, and the resist pattern is removed with an organic solvent, thereby forming a water-soluble mask pattern 12 as shown in FIG. The subsequent steps are the same as those described with reference to FIGS. 2 to 4, but the drying temperature after applying the dispersion of the high conductivity material is desirably about 60 ° C. When such a water-soluble mask pattern is used, the degree of freedom of the organic solvent that can be used for the dispersion of the high-conductivity material is increased, so that the production becomes easier.

[Effects of the Invention] As described above, according to the present invention, the power consumed to stabilize the surface potential of the substrate around the electron-emitting device and stabilize the trajectory of the electron beam emitted from the electron-emitting device is reduced. , Which can be reduced to 1/20 to 1/200 of the conventional one.

[Brief description of the drawings]

1 to 3 are views showing an intermediate process of manufacturing an electron beam generator according to the present invention, FIG. 4 is a first embodiment of the present invention, and FIGS. 5 and 6 are other embodiments. 7, 8 and 9 show another manufacturing method, FIG. 10 shows another embodiment,
11 and 12 are views showing another manufacturing method. 1 is an insulating substrate, 2 is a positive electrode, 3 is a negative electrode, 4 is a photoresist pattern, 5 and 7 are areas coated with a high conductivity material so as to have a resistance of 1 × 10 ⁴ to 1 × 10 ⁷ Ω / □, 6 and 8 are 1 × 10 ⁸
This is a region coated with a high conductivity material so as to have a resistance of about 1 × 10 ¹⁰ Ω / □.

Continued on the front page (72) Inventor Tetsuya Kaneko 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Yoshikazu Saka 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Toshihiko Takeda 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References Patent 2630988 (JP, B2)

Claims (5)

(57) [Claims] 1. An electron beam generator comprising an electron-emitting device having an electron-emitting portion between electrodes on an insulating substrate surface, wherein an electric resistance of 1 × 10 ⁸ is provided at least around the inter-electrode region on the insulating substrate surface. A first conductive film in a range of 1 × 10 ¹⁰ Ω / □ to 1 × 10 ⁴ to 1 × 10 ⁴ Ω / □;
An electron beam generator comprising a second conductive film including an electron emission portion in a range of × 10 ⁷ Ω / □. 2. The electron beam generator according to claim 1, wherein said first and second conductive films are mainly made of the same material. 3. The electron beam generator according to claim 1, wherein each of the first and second conductive films is made of fine particles. 4. An electron beam generator according to claim 3, wherein said first and second conductive films are conductive films having different particle densities. 5. The electron beam generator according to claim 1, wherein said electron-emitting device is a surface conduction electron-emitting device.