JPH04359830A - Electron emitting device and image forming apparatus using device therein - Google Patents

Abstract

PURPOSE:To provide electron emitting devices which have self-promoting property to correct defects of electron emitting parts without being given any structural alteration from outside and have little fluctuation of properties among the devices. CONSTITUTION:An electron emitting device has a characteristic wherein a plurality of electron emitting parts 5 electrically connected in series between a pair of electrodes 1, 2 and single electron emitting part 5 are arranged electrically in parallel rows one another and the total number of the electron emitting parts for each row arranged in parallel is different from that of another row.

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 and an image forming apparatus using the device.

0002

[Prior Art] Conventionally, as an element that can emit electrons with a simple structure, for example, MI Ellingson (M
．． I. The cold cathode device announced by Radio Engineering Electron Physics (RadioEng. Elinson) and others is known.
ectron Phys. ) Volume 10, 1290-1
296 pages, 1965].

[0003] This device utilizes the phenomenon that electrons are emitted when a current is passed in parallel to a thin film of small area formed on a substrate, and is generally called a surface conduction electron-emitting device. It is.

These surface conduction electron-emitting devices include those using the SnO2 (Sb) thin film developed by Ellingson et al., and those using an Au thin film [G. Dittmer "Sin Solid Films"]
er: “Thin Solid Films”), Vol. 9, p. 317, (1972)], ITO thin film [
M. Hartwell and C.G. Fostad “Ieeeeee Trans” Edie Conference (M.Hartwell and C.G.Fo
nstad;“IEEE Trans.ED Co
nf. ”) p. 519, (1975)], carbon thin film [Hisashi Araki et al.: “Vacuum” Vol. 26, No. 1, 2
2, (1983)] have been reported.

A typical device configuration of these surface conduction type electron-emitting devices is shown in FIG. In the figure, 1 and 2 are electrodes for obtaining electrical connection, 8 is a thin film formed of an electron-emitting material, 4 is a substrate, and 5 is an electron-emitting part.

[0006] Conventionally, in these surface conduction type electron-emitting devices, an electron-emitting portion is formed in advance by an electrical heating process called forming before electron emission. That is, by applying a voltage between the electrode 1 and the electrode 2,
The thin film 8 is energized, and the Joule heat generated thereby locally destroys, deforms, or alters the thin film 8 to form an electron-emitting region 5 in an electrically high resistance state, thereby obtaining an electron-emitting function. There is.

[0007] The electrically high resistance state refers to a discontinuous state film in which a portion of the thin film 8 has a crack of 0.5 μm to 5 μm, and the inside of the crack has a so-called island structure. The island structure generally refers to a film in which fine particles with a diameter of several tens of angstroms to several micrometers are present on the substrate 4, and each fine particle is spatially discontinuous but electrically continuous.

Conventionally, the surface conduction type electron-emitting device is one in which a voltage is applied to the above-mentioned high-resistance discontinuous film through the electrodes 1 and 2, and a current is caused to flow across the surface of the device, thereby causing the above-mentioned fine particles to emit electrons.

However, the above-mentioned conventional forming element using electrical heating has the following problems.

1) Since it is impossible to design a sea-island structure that serves as an electron-emitting region, it is difficult to improve the device, and variations between devices are likely to occur.

2) Since the Joule heat generated during the forming process is large, the base is easily destroyed and it is difficult to mulch.

3) The material of the island is gold, silver, SnO2, ITO
Because it is not possible to use materials with small work functions limited to
Unable to obtain large current.

Due to the above-mentioned problems, surface conduction electron-emitting devices have not been actively applied in industry, despite having the advantage of a simple device structure. .

[0014] As a result of studies in view of the above-mentioned problems, the present inventors have found that
In Japanese Patent No. 822, a novel surface conduction type electron-emitting device was proposed in which an electron-emitting portion was provided by disposing a fine particle film between electrodes and subjecting the film to an electric current treatment. A configuration diagram of this new electron-emitting device is shown in FIG.

In the figure, 1 and 2 are electrodes, 3 is a fine particle film, 5 is an electron emitting part, and 4 is a substrate.

The characteristics of this electron-emitting device are as follows.

1) Since the electron emitting region can be formed by passing a very small current through the fine particle film, an element without deterioration can be formed, and furthermore, the shape of the electrode can be arbitrarily designed.

2) Since the fine particles forming the fine particle film themselves serve as constituent materials for electron emission, it is possible to design the material, shape, etc. of the fine particles, and the electron emission characteristics can be changed.

3) The selection of materials for the substrate and electrodes, which are the constituent materials of the element, is expanded.

On the other hand, an electron emitting device is known in which a plurality of electron sources are spread out in a planar manner at equal intervals vertically and horizontally (Japanese Unexamined Patent Publication No. 56-2
Publication No. 8445).

Unfortunately, however, the electron emission device described above uses a coiled heater-type hot cathode as an electron source, resulting in low electron emission efficiency and a complicated structure, resulting in low power consumption of the device. It has not been put into practical use because of the enormous manufacturing costs.

[0022]

SUMMARY OF THE INVENTION However, the conventional surface conduction type emitting device manufactured by the conventional forming process using electrical heating has the following problems.

(2) Since it is impossible to design the structure of the emission section, it is difficult to improve the device, and variations between devices are likely to occur.

(2) Since the Joule heat generated by the forming process is large, deterioration of characteristics and destruction of the substrate are likely to occur.

[0025] In addition, in the thermionic electron sources using electrical heating, which have been put into practical use in the past, the electron emission characteristics are extremely strongly affected by temperature distribution, so it is difficult to obtain uniform characteristics over a large area. It has not been applied to an electron-emitting device developed in a shape or a planar shape.

Furthermore, when the conventional surface conduction type emitter and the thermionic source using electrical heating are electrically arranged in series, there are the following problems.

(2) Electrons cannot be emitted from only one of two or more emitting portions connected in series, or from only one of a plurality of emitting portions.

(2) Since the voltage is divided in each emission part by series connection, the driving voltage becomes high and the power consumption increases.

(2) Due to the voltage drop at the emission part, variations occur in the voltage applied to the element, and the amount of electron emission is not uniform.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electron-emitting device and an image forming apparatus using the device, which can solve the above-mentioned problems.

[0031]

[Means and Operations for Solving the Problems] The features of the present invention will be described below.

The first feature of the present invention is that a pair of electrodes is provided on an insulating substrate, and a plurality of electron emitting parts or a single electron emitting part are electrically connected in series between the pair of electrodes. are electrically arranged in parallel in a plurality of rows, and each of the plurality of parallel rows has at least a different number of electron-emitting regions in total. .

[0033] Secondly, the plurality of electron emitting portions are electron emitting elements made of a fine particle film that electrically connects the pair of electrodes.

Third, an electron source in which at least a plurality of electron-emitting devices according to the above-mentioned item 1 are arranged in a vacuum container, and an image forming member that forms an image by irradiation with electrons emitted from the electron source are provided. It is characterized by an image forming apparatus.

That is, the basic technical idea of the present invention is that at least two or more electron-emitting portions of an electron-emitting device are electrically parallel to each other, and at least one of the two or more locations is electrically connected to a plurality of electron-emitting portions in series. The above-mentioned problem is solved by connecting electron-emitting parts to form an electron-emitting element.

The components and functions of the present invention will be explained in detail below.

[0037] Examples of the fine particle film in the present invention include a film of conductive fine particles having a particle size of a dozen or more angstroms to several μm, or a carbon thin film in which these conductive fine particles are dispersed. The material is metal such as Pd, Ag, Au, Ti, Pd
Any conductive oxide conductor material such as O, SnO2, etc. may be used. These films are formed between the electrodes by a gas deposition method, a dispersion coating method, or the like.

Next, the operation of the structure in which the electron emitting portions are electrically connected in series, which is one of the features of the present invention, will be explained with reference to the drawings.

FIG. 1 is a device configuration diagram showing a configuration in which electron emitting portions are electrically connected in series, which is one of the features of the present invention.

In the figure, 1 and 2 are electrodes, 3 is an electron-emitting material made of a fine particle film, 4 is an insulating substrate, 5 is an electron-emitting part, and 6 is a fluorescent material made of a transparent plate 61, a transparent electrode 62, and a phosphor 63. The body target 7 is an electron irradiation area (light emitting part).

The electron-emitting device of the present invention is shown in FIGS. 1, 2, and 3.
, and as shown in FIG. Department)
It has a configuration corresponding to 7.

[0042] The spacing between the electrodes 1 and 2 forming the electron emitting portion 5 is preferably 0.1 μm to 100 μm, and generally 0.1 μm to 100 μm.
．． 5 μm to 10 μm is practical. Further, the spacing S between adjacent electron emitting parts 5 is desirably 0.5 μm to 2 mm, and generally 1 μm to 1000 μm is practical.

The method of energizing the particulate film 3 made of an electron-emitting material provided in the plurality of electron-emitting parts 5 as described above is such that part of the particulate film is made to have a high resistance by heating with electricity. There are some that form an electron-emitting part by passing electricity through the particulate film 3, and others that lower the resistance of a part of the particulate film 3 to form an electron-emitting part. By performing the above-mentioned treatment, the structure of the fine particle film made of all the electron-emitting materials is changed, and the discontinuous electron-emitting portions as described above are formed.

Next, when a driving voltage is applied to the surface conduction type electron-emitting device that has been subjected to the energization treatment, only one of the electron-emitting portions 5 out of the plurality of electron-emitting portions emits electrons. Obtained. In fact, it is unclear how only one electron-emitting region 5 can emit electrons, but the inventors of the present invention have proposed a characteristic unique to the novel surface-conduction electron-emitting device. I guess.

Further, as shown in FIG. 1, the electron irradiation region (light emitting section) 7 by the surface conduction electron-emitting device has a nearly circular shape with L>W due to its characteristics.

Next, FIG. 2 best represents the characteristics of the present invention.
The effect of the electron-emitting device for a configuration in which two or more electron-emitting parts are arranged in parallel and at least one of the two or more electron-emitting parts is arranged in series, using will be explained using drawings.

In the figure, 1 and 2 are electrodes, 3 is an electron-emitting material made of a fine particle film, and 4 is an insulating substrate 5, which is an electron-emitting portion.

In the figure, two electron emitting parts are connected in series and one
This is an electron-emitting element in which one electron-emitting part and a pair of electrodes are connected in parallel, and the electron-emitting part is formed by applying electricity to the electrodes 1 and 2 as described above.

Next, when a driving voltage is applied to the electron-emitting device that has been subjected to the energization process, the same driving voltage is applied to the electron-emitting parts connected in parallel, and from one electron-emitting part Electron emission is obtained as shown below. At this time, electric field concentration occurs in one of the two series-connected emission parts, and it tries to function as an electron-emitting element, but the remaining electron-emission part is a surface conduction type electron-emitting element that is subjected to energization treatment. The driving voltage is divided between the two electron-emitting parts connected in series and applied to each electron-emitting part, since the two electron-emitting parts act as a resistor with a specific resistance of . Then, the electron emitting section in which the electric field concentration occurs is not applied with a driving voltage up to a level that allows a practically required amount of electron emission to be obtained, and electrons are emitted only from one electron emitting section connected in parallel.

Furthermore, if the electron emitting section stops its electron emitting function due to some problem, if a driving voltage is further applied, electrons will be ejected from one of the two electron emitting sections connected in parallel and in series. It has the effect of providing release.

[0051]

[Examples] The present invention will be explained in further detail using Examples below.

Example 1 FIG. 2 is an element configuration diagram showing this example. First, the method for manufacturing the electron-emitting device of this example will be explained using the same figure.

(2) A quartz substrate was used as the insulating substrate 4, thoroughly cleaned with an organic solvent, etc., and electron emitting portions were formed in series and in parallel using vacuum evaporation technology and photolithography technology to form electrodes 1 and 2.

The electrode may be made of any material as long as it has conductivity, but in this example, Ni metal was used.

[0055] Further, it is practically preferable that the intervals between the electron emitting portions 5 arranged in series be 1.0 μm to 1000 μm, and in this embodiment, the intervals were set to 10 μm. In addition, it is desirable for the electrode spacing to be practically 0.5 μm to 20 μm, and in this example, the electrode spacing was 6 μm, and the film thickness was 1000 Å. The widths l1 and l2 of the electron emitting portion 5 may have any value, but in this embodiment, they are l1=l2=300 μm.

(2) Next, organic palladium is dispersed and coated between the electrodes 1 and 2. Organic palladium is manufactured by Okuno Pharmaceutical Co., Ltd. C
CP-4230 was used.

A tape or resist film was provided in areas where it was not desired to disperse fine particles, and then organic palladium was applied by dipping or spinner method. Next, by peeling off the tape or resist film, a fine particle film 3 made of an electron-emitting material was produced at a predetermined position. Next, it was fired at 300° C. for 1 hour to disperse organic palladium and form a fine particle film containing a mixture of palladium and palladium oxide. At this time, the diameters of the fine particles of palladium and palladium oxide are both 10 Å ~
Although the thickness was 150 Å, the present invention is not limited to this.

(2) Next, the electrode 1 was connected to a power source so that it was on the negative side and the electrode 2 was on the positive side, and the fine particle film 4 made of an electron-emitting material was energized three times. As a result, 3 electron-emitting portions 5 including two electron-emitting portions 5 electrically formed in series are formed.
Electron emitting regions 5 were formed at several locations.

[0059] Here, the practical thickness of the fine particle film before the current treatment is from several tens of angstroms to 200 angstroms, but it is not limited to this. Note that the sheet resistance of the fine particle film at this time is 103~
It is about 1010Ω/□.

In this example, the direction of current flow was from electrode 2 to electrode 1 during the energization process; can be formed.

When a voltage was applied to the electron-emitting device configured as described above to emit electrons, only one electron-emitting portion 5 was formed between the electrodes 1 and 2 other than the electron-emitting portion configured in series. The emission of electrons was obtained from Furthermore, since electron emission stopped for some reason, the applied voltage was increased, and electron emission equivalent to the above-mentioned electron emission was obtained from one of the electron emission parts 5 configured in series.

The electron-emitting device of this example can be emitted by applying only an applied voltage without any external structural change.
We were able to obtain redundancy for electron emission.

The ability to construct an electron-emitting device with redundancy has a very important meaning when considering applications. For example, even if a defect occurs in the electron emitting portion 5 during device manufacturing, electron emission can be obtained without any correction. Furthermore, even if the electron-emitting device is used in an image forming apparatus or the like, the repair process can be simplified. Therefore, the device of this example provides a practically very effective device.

Furthermore, since electron emission can be obtained from three electron emitting parts, durability can be increased by about three times.

It goes without saying that the amount of electron emission can be controlled by changing the width of the electron emission section 5.

Embodiment 2 FIG. 3 is an element configuration diagram showing another embodiment of the present invention. First, a method for manufacturing the electron-emitting device of this example will be explained with reference to the drawings.

(2) A quartz substrate was used as the insulating substrate 4, thoroughly cleaned with an organic solvent, etc., and electron emitting portions were formed in series and in parallel using vacuum evaporation technology and photolithography technology, and electrodes 1 and 2 were formed. In this example, Ni metal was used as the electrode material.

Further, the intervals between the electron emitting parts 5 arranged in series are 10 μm in this embodiment, the electrode intervals are 6 μm in this embodiment, the film thickness is 1000 Å, and the width of the electron emitting parts 5 is 10 μm in this embodiment. l1=l3=100μm, l2=2
00 μm.

(2) Next, a metal mask was placed between the electrodes 1 and 2 in order to form a particulate film at a predetermined position, and a particulate film 4 made of Pd was produced by a gas deposition method. Further, the particle size of the Pd fine particles was 50 Å to 150 Å.

■ Same as Example 1-■.

When a voltage is applied to the electron-emitting device configured as described above to emit electrons, two electron-emitting portions 5 are formed between the electrodes 1 and 2 other than the electron-emitting portions configured in series. Electron emission was obtained from Furthermore, when the applied voltage was increased because electron emission stopped for some reason, electron emission equivalent to the above-mentioned electron emission was obtained from one of the electron emission parts 5 configured in series, and the effect was equivalent to that of Example 1. was there.

Embodiment 3 FIG. 4 is an element configuration diagram showing another embodiment of the present invention. In this embodiment, as shown in the figure, two electron emitting parts 5 are connected in series.
The shape is almost the same as that of Example 1, except that three electron emitting sections 5 are connected in parallel and the width of the electron emitting section is l1=l2=300 μm.

[0073] Further, the production of this example was carried out in the same manner as in Example 1, except that the energization treatment was performed five times.

When a voltage was applied to the electron-emitting device constructed as described above to emit electrons, electrons were emitted from one of the two electron-emitting portions 5 in series. Furthermore, although electron emission stopped for some reason, electron emission was obtained from the other electron-emitting part. This is because the electron emitting section, which has stopped emitting electrons, has failed in a low resistance state. Furthermore, when the applied voltage was increased because the electron emission of the other electron emitting part stopped, three of the electron emitting parts configured in series
Emission of electrons equivalent to that emitted from the two electron emitting parts in series was obtained from one of the electron emitting parts, and the same effect as in Example 1 was obtained.

Embodiment 4 FIG. 5 is a block diagram showing an embodiment of an image forming apparatus according to the present invention. The planar electron source of this example is one in which a plurality of electron-emitting devices of Example 1 are arranged, and in particular, a plurality of line electron sources in which electron-emitting devices are arranged in parallel between electrodes 1 and 2 are arranged on a substrate. It is set up in a regular manner.

In FIG. 5, 6 is a phosphor target consisting of a transparent plate, a phosphor, and a metal back, 7 is an electron irradiation area that becomes a bright spot of the phosphor, 9 is a grid electrode, and 10 is an electron passage hole.

In this embodiment, the grid electrode 9 consists of a plurality of line electrode groups and is arranged perpendicularly to the electrode group of the planar electron source. The electron passing hole 10 is provided almost vertically above the electron emitting section 5, and uses the grid electrode 9 as a signal electrode and the line electron source group as a scanning electrode, and performs XY matrix driving to form an image.

As shown in FIG. 5, the phosphor target 6 is a transparent glass plate on which phosphor is uniformly coated, and a metal back is further provided thereon.

In the image forming apparatus of this embodiment, the electrode 1
By applying a voltage of 14 V to the electrodes 2 and 2, electrons are emitted from only one of the electron emitting parts 5 connected in parallel and in series, and the grid electrode Electrons were extracted by applying an appropriate voltage to the phosphor target 9, and the electrons were caused to collide with the phosphor target 6. This image forming apparatus naturally has a vacuum level of 1 x 10-5t.
The phosphor target 6 was placed under an environment of orr to 1×10 −7 torr, and a voltage of 500 to 5000 V was applied to the phosphor target 6.

In this example, the following results were obtained when compared with a conventional image forming apparatus in which the electron irradiation area and the electron emission section are arranged one to one.

(1) This embodiment has self-redundancy because the electron-emitting parts are arranged in parallel and in series.
Image defects could be corrected without any external structural changes.

(2) Similarly, by having a plurality of electron emitting parts in one pixel, the effect of extending the life span was obtained.

(3) Furthermore, even if a defect occurs in the electron-emitting part of a planar electron source during manufacturing, it has self-redundancy with multiple electron-emitting parts in one pixel. This has the effect of improving the yield of the source.

Up to this point, only the image forming apparatus has been described in this embodiment. However, in addition to phosphors, the image forming member can also be any material whose state changes when an electron beam collides with it, such as a resist material or a thin film metal. There are various types of electron beam application devices such as recording devices, storage devices, and electron beam lithography devices. A forming device would have the same effect.

[0085]

As explained above, by having a plurality of electron emitting sections electrically connected in series and parallel, the following effects can be obtained as an electron emitting device or an image forming apparatus.

(1) Not only can an electron-emitting device with self-redundancy capable of repairing defects in the electron-emitting portion without making any external changes to the structure be provided, but also there is little variation in characteristics between devices. The device and manufacturing became possible.

(2) The yield during manufacturing of the electron-emitting portion can be improved.

(3) Since it is composed of a plurality of electron emitting parts, it has the effect of improving the life of electron emission.

(4) An image display with uniform luminescent spots can be obtained as an image forming apparatus.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one of the features of the present invention.

FIG. 2 is a configuration diagram of an electron-emitting device in Example 1.

FIG. 3 is a configuration diagram of an electron-emitting device in Example 2.

FIG. 4 is a configuration diagram of an electron-emitting device in Example 3.

FIG. 5 is a configuration diagram of an image forming apparatus in Embodiment 4.

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

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

[Explanation of symbols]

1, 2 Electrode 3 Particulate film 4 Board 5　Electron emission part 6. Phosphor target 7 Electron irradiation area (light emitting part) 8 Thin film 9 Grid electrode 10 Passing hole

Claims (3)

[Claims] Claim 1: A plurality of electron emitting parts or a single electron emitting part electrically connected in series between a pair of electrodes are electrically arranged in a plurality of rows, and each of the electron emitting parts arranged in parallel An electron-emitting device characterized by having at least parallel rows in which the total number of parts is different from each other. 2. The electron-emitting device according to claim 1, further comprising an electron-emitting portion made of a fine particle film that electrically connects a pair of electrodes. 3. A vacuum container is provided with at least an electron source in which a plurality of electron-emitting devices according to claim 1 are arranged, and an image forming member that forms an image by irradiation with electrons emitted from the electron source. An image forming apparatus characterized by: