JP5783798B2 - ELECTRON EMITTING ELEMENT AND DEVICE EQUIPPED WITH THE SAME - Google Patents

Description

  The present invention relates to an electron-emitting device that emits electrons by applying a voltage, and various devices including the electron-emitting device.

  As a conventional electron-emitting device, an electron-emitting device composed of a Spindt type electrode, a carbon nanotube (CNT) type electrode, or the like is known. This electron-emitting device has been studied for application in the field of FED (Field Emission Display), for example. A voltage is applied to the sharp portion to form a strong electric field of about 1 GV / m, and electrons are generated by the tunnel effect. Can be released.

However, since these two types of electron-emitting devices have a strong electric field in the vicinity of the surface of the electron-emitting portion, the emitted electrons obtain large energy by the electric field and easily ionize gas molecules. The cation generated by the ionization of gas molecules is accelerated and collides in the direction of the surface of the device by a strong electric field, and there is a problem that the device is destroyed by sputtering.
In addition, since oxygen in the atmosphere has lower dissociation energy than ionization energy, ozone is generated prior to the generation of ions. Since ozone is harmful to the human body and oxidizes various things with its strong oxidizing power, there is a problem of damaging members around the element. To avoid this, the surrounding members are ozone resistant. There is a restriction that high material must be used.

Against this background, MIM (Metal Insulator Metal) type and MIS (Metal Insulator Semiconductor) type electron emitting devices have been developed as other types of electron emitting devices.
These are surface-emission electron-emitting devices that accelerate electrons using the quantum size effect and strong electric field inside the device to emit electrons from the planar device surface.
Since these electron-emitting devices emit electrons accelerated by an electron acceleration layer inside the device, a strong electric field is not required outside the device.
Therefore, the MIM type and MIS type electron-emitting devices overcome the problem of being destroyed by sputtering due to ionization of gas molecules and the generation of ozone like the Spindt-type, CNT-type, and BN-type electron-emitting devices. it can.

However, MIM type and MIS type electron-emitting devices are generally prone to pinholes and dielectric breakdown. Therefore, it is known that these electron-emitting devices use an insulating film having fine particles to prevent the occurrence of pinholes or dielectric breakdown.
For example, an MIM type electron-emitting device is known in which an insulator containing fine particles is provided between two electrodes facing each other (see, for example, Patent Document 1).

  Further, the substrate, an electron emission portion on the substrate made of a carbon-based electron emission material (for example, carbon nanotube), a fixed layer formed on the substrate thicker than the electron emission portion, and the electron emission portion are opposed to each other. And an electron extraction electrode for extracting electrons from the electron emission portion, and the fixed layer includes a powder layer made of insulating particles and an oxide formed to cover the powder layer. An electron-emitting device that is an insulating film made of an insulator is known (for example, see Patent Document 2).

JP-A-1-298623 JP 2000-31640 A

Carbon nanotube emitters and carbon black emitters have uneven electron emission points due to variations in the size and density of carbon nanotubes and carbon black.
In order to solve this problem, activation processing such as energization aging, laser irradiation, and plasma processing has been attempted, but the processing takes time and effort.

Further, although the mechanism of the MIM type and MIS type electron emitting devices has not been clearly clarified, the electron emission points become non-uniform due to the micro electric non-uniformity generated in the device structure.
Some of these electron-emitting devices are subjected to energization treatment for stabilization, that is, a forming process, but the electron emission point formed by the forming process is accidental. It is difficult to control the emission point, and in many cases it becomes non-uniform.

  The present invention has been made in view of such circumstances, and mainly provides an electron-emitting device capable of emitting electrons uniformly and with good controllability.

  According to the present invention, the first electrode, the electron emission control insulating film formed on the first electrode and having a plurality of small holes penetrating in the film thickness direction, and formed on the electron emission control insulating film A first electrode comprising: an electron acceleration layer containing at least insulating fine particles; and a second electrode formed on the electron acceleration layer, and applying a voltage between the first electrode and the second electrode. Provided is an electron-emitting device characterized in that electrons emitted from the electron-emission controlling insulating film are accelerated by the electron acceleration layer at the position of the small hole and emitted from the second electrode to the outside. Is done.

  According to another aspect of the present invention, a step (A) of forming an electron emission control insulating film having a plurality of small holes penetrating in the film thickness direction on the first electrode, and the electron emission control insulating film A step (B) of forming an electron acceleration layer containing at least insulating fine particles on the first electrode in the small hole, and a step (C) of forming a second electrode on the electron acceleration layer. An electron-emitting device manufacturing method is provided.

In the electron-emitting device of the present invention, by applying a voltage between the first electrode and the second electrode, the electrons emitted from the first electrode are converted into the electrons at the positions of the small holes of the electron emission control insulating film. The acceleration layer is accelerated and emitted from the second electrode to the outside.
Therefore, uniform and controllable electron emission can be realized.
In addition, since the device breakdown due to local electron emission can be reduced, the device can be expected to have a long lifetime.
In addition, according to the method for manufacturing an electron-emitting device of the present invention, it is possible to manufacture an electron-emitting device that can realize uniform and controllable electron emission and has a long lifetime.

It is a schematic diagram which shows the structure of Embodiment 1-1 of the electron emission element of this invention. It is a schematic diagram which shows the structure of Embodiment 1-2 of the electron-emitting element of this invention. It is a schematic diagram which shows the experimental system for confirming an electron emission point using the electron-emitting element of Embodiment 1-1 demonstrated in FIG. It is a schematic diagram showing an example of a charging device using the electron-emitting device of Embodiment 1 (Embodiments 1-1 to 1-2). It is a schematic diagram which shows the self-light-emitting device of Embodiment 3-1 using the electron-emitting device of Embodiment 1. It is a schematic diagram which shows the self-light-emitting device of Embodiment 3-2 using the electron-emitting device of Embodiment 1. It is a schematic diagram which shows the self-light-emitting device of Embodiment 3-3 using another electron emission element. It is a schematic diagram which shows the image display apparatus of Embodiment 3-4 using the self-light-emitting device of Embodiment 3-3. It is a schematic diagram which shows the ion wind generator of Embodiment 4-1 using the electron-emitting device of Embodiment 1. It is a schematic diagram which shows the ion wind generator of Embodiment 4-2 using the electron-emitting device of Embodiment 1. 2 is a photograph showing electron emission points in the electron-emitting device of Example 1. FIG. 2 is a photograph showing electron emission points in the electron-emitting device of Example 1. FIG. 6 is a photograph showing electron emission points in the electron-emitting device of Example 2. FIG. 6 is a photograph showing electron emission points in the electron-emitting device of Example 3. FIG. 6 is a photograph showing electron emission points in the electron-emitting device of Example 4. 6 is a photograph showing electron emission points in the electron-emitting device of Example 5. FIG. 10 is a photograph showing electron emission points in the electron-emitting device of Example 6. 10 is a photograph showing electron emission points in the electron-emitting device of Example 7. FIG. 6 is a photograph showing electron emission points in the electron-emitting device of Comparative Example 1. 6 is a photograph showing electron emission points in the electron-emitting device of Comparative Example 1. 6 is a photograph showing an electron emission point in the electron-emitting device of Comparative Example 2. 6 is a photograph showing an electron emission point in the electron-emitting device of Comparative Example 2.

The electron-emitting device of the present invention includes a first electrode, an electron emission control insulating film formed on the first electrode and having a plurality of small holes penetrating in the film thickness direction, the electron emission control insulating film, and the small An electron acceleration layer containing at least insulating fine particles formed in the hole and a second electrode formed on the electron acceleration layer are provided, and a voltage is applied between the first electrode and the second electrode. Thus, the electrons emitted from the first electrode are accelerated by the electron acceleration layer at the position of the small hole of the electron emission control insulating film and emitted from the second electrode to the outside.
In other words, the electron-emitting device of the present invention provides an outer surface of the second electrode by providing an electron emission control insulating film having a plurality of uniformly arranged small holes on the first electrode side between the first and second electrodes. Can uniformly emit electrons.

Here, the mechanism of electron emission of the electron-emitting device of the present invention will be described.
In the electron-emitting device of the present invention, when a voltage is applied between the first electrode and the second electrode, the insulating fine particles in the electron acceleration layer between the first electrode and the second electrode from the first electrode. Electrons move to the surface of Since the inside of the insulating fine particles has a high resistance, electrons are conducted through the surface of the insulating fine particles.
At this time, electrons are trapped by impurities on the surface of the insulating fine particles, oxygen defects when the insulating fine particles are oxides, or contacts between the insulating fine particles. The trapped electrons work as fixed charges.
As a result, on the surface of the electron acceleration layer, the applied voltage and the electric field created by the trapped electrons are combined to generate a strong electric field. The strong electric field accelerates the electrons, and the electrons are emitted from the second electrode.

On the other hand, when this mechanism is viewed from a macro viewpoint, the electron emission control insulating film has a plurality of small holes penetrating in the thickness direction, and electrons move from the first electrode to the electron acceleration layer that has entered the small holes. Then, electrons are emitted by the mechanism.
The electron emission control insulating film has high electrical resistance, and electrons from the first electrode do not move from the electron emission control insulating film to the upper layer, so that electron emission does not occur.
As a result, electrons are emitted only from the small holes, and electrons are uniformly emitted from the small holes arranged in the entire device. In addition, since the device structure is such that electrons are emitted according to the pattern of the electron emission control insulating film, electrons are emitted with good controllability.
As described above, the electron-emitting device according to the present invention has a pattern structure in which the electron emission control insulating film has portions (small holes) and portions that do not emit electrons alternately arranged. Electrons can be emitted with good controllability.

  The voltage applied to the electron-emitting device may be either a DC voltage or an AC voltage, but an AC voltage with a relatively stable electron emission amount is preferred. Hereinafter, in the present specification, the term “voltage” refers to both “AC voltage” and “DC voltage”.

The method for manufacturing an electron-emitting device according to the present invention includes a step (A) of forming an electron emission control insulating film having a plurality of small holes penetrating in the film thickness direction on the first electrode, and the electron emission control insulation. A step (B) of forming an electron acceleration layer containing insulating fine particles on the first electrode so as to cover the film; and a step (C) of forming a second electrode on the electron acceleration layer. With this manufacturing method, the above-described electron-emitting device can be manufactured.
Here, when manufacturing an electron-emitting device in which the film thickness of the electron acceleration layer is equal to the film thickness of the electron emission control insulating film, for example, etching or chemical mechanical polishing (step) between the process (B) and the process (C). A step of removing the electron acceleration layer by CMP) until the electron emission control insulating film is exposed is included.
In this case, in the step (C), the second electrode is formed on the electron acceleration layer and the electron emission control insulating film in each small hole.
In the following, various embodiments of the present invention will be described.
In the present specification, “to” in a numerical range includes numerical values at both ends. For example, “0.3 to 2.0 μm” means “0.3 μm or more and 2.0 μm or less”, and includes numerical values “0.3 μm” and “2.0 μm” at both ends.

In the electron emission device of the present invention, in the embodiment, the electron emission control insulating film includes, for example, an inorganic film such as a silicon oxide film, a silicon nitride film, and a silicon oxynitride film, a silicone resin film, an acrylic resin film, and a polyimide film. An insulating film such as an organic film such as a resin film, an epoxy resin film, a polyester resin film, a polyurethane resin film, or a polystyrene resin film may be used. Among these embodiments, a silicon oxide film, a silicon nitride film, a silicone resin film, an acrylic resin film, and a polyimide resin film are more preferable from the viewpoints of resistance value, heat resistance, water absorption, mechanical strength, and the like.
The film thickness of these insulating films varies depending on the magnitude of the voltage applied to the electron-emitting device, but can be set to 0.1 to 3 μm, for example.
Further, the electron emission controlling insulating film may be a single layer film or a laminated film of these various insulating films.

In the embodiment of the present invention, the size, shape, density, and the like of the plurality of small holes formed in the electron emission control insulating film may be such that the electric fields in the adjacent small holes do not interfere with each other. The small holes may be arranged at random, but are preferably arranged in a matrix in the vertical and horizontal order from the viewpoint of more uniformly emitting electrons from the electron-emitting devices.
More specifically, in the embodiment of the present invention, the size of the small hole is, for example, a size that fits in a square having a side of 1 to 500 μm, and more specifically, an inner diameter of 5 to 300 μm. . If the inner diameter of the small hole is too small with respect to the thickness of the electron acceleration layer, the electric field in the small hole tends to weaken and the electron emission efficiency tends to decrease, and conversely, if the inner diameter is too large, The effect of the invention (ie, the uniformity of electron emission) tends to be impaired. For this reason, the inner diameter of the small hole is preferably 8.5 to 300 times the thickness of the electron acceleration layer. As a specific numerical range, 21.2 to 141.4 μm (21 to 140 μm when the third digit is rounded off) Is preferred. Here, the layer thickness of the electron acceleration layer is preferably 0.3 to 2.0 μm as described later.
On the other hand, the shape of the small holes is not particularly limited. In the embodiment of the present invention, the planar view shape is, for example, a polygon (regular triangle, square, rectangle, rhombus, pentagon, hexagon, regular polygon, etc.), circle, ellipse or the like. Among these shapes, a shape in which the ratio of the length of the major axis to the minor axis is preferably 1 to 2 in terms of not having a sharp apex where electrons tend to concentrate, and an ellipse that realizes this ratio is more preferable. Further, among these shapes, a circular shape that has the most gentle curvature when compared in the same area is more preferable.
At this time, the cross-sectional shape of the small hole in the film thickness direction is preferably rectangular or square so that electrons can be stably emitted in the vertical direction from the outer surface of the second electrode of the electron-emitting device.
In the embodiment of the present invention, the small holes are disposed in the electron emission control insulating film at a density of 5 to 2000 holes / mm ² .
In the present invention, the inner diameter of the small hole is the length of the longest diagonal line when the small hole has a circular shape in plan view, a circle diameter, an elliptical shape, a long diameter, or a polygonal shape. Further, in the present invention, the minor diameter of the small hole is not only the short diameter when the planar view shape of the small hole is an ellipse (ellipse), but also the shortest diagonal line when the planar view shape of the small hole is a polygon. Including the length of The same applies to the long diameter. In the present invention, the long diameter of the small hole includes the length of the longest diagonal line when the shape of the small hole in plan view is a polygon. Here, when the planar view shape of the small hole is a polygon, a shape formed by a photolithography process and having an arc shape at the apex thereof is also included.

If the size, shape, density, etc. of the small holes are set such that the electric fields in the adjacent small holes interfere with each other, the electron emission uniformity and controllability are impaired.
As described above, the electron emission control insulating film is an insulating film formed on the first electrode, and has a function of uniformly controlling the electron emission of the electron-emitting device in the plane by having a plurality of small holes. .

In the embodiment of the present invention, in addition to the configuration of the invention, a carbon thin film may be formed on the surface of the electron acceleration layer on the second electrode side.
With this configuration, sufficient electrons can be emitted at an appropriate voltage, and dielectric breakdown is unlikely to occur, and continuous operation for a long time is possible. The carbon thin film will be described in detail later.

  In addition, in the embodiment of the method for manufacturing an electron-emitting device according to the present invention, in addition to the configuration of the manufacturing method, the step (A) includes, for example, a step (A1) of forming an insulating film on the first electrode. A step (A2) of forming a resist pattern film on the insulating film, and etching the insulating film using the resist pattern film as a mask to form the plurality of small holes, thereby forming the electron emission controlling insulating film Forming (A3).

In addition, in the method of manufacturing an electron-emitting device according to the present invention, in the case of manufacturing the electron-emitting device having the carbon thin film, a step of forming the carbon thin film on the surface of the electron acceleration layer on the second electrode side is provided. In addition.
In other words, the carbon thin film forming step is performed between step (A) and step (B), between step (B) and step (C), or both.

In the embodiment of the method for manufacturing an electron-emitting device of the present invention, the step (B) includes, for example, a step (B1) of preparing a fine particle dispersion in which insulating fine particles are dispersed in a solvent, and the electron A step (B2) of applying the fine particle dispersion onto the release controlling insulating film; and a step (B3) of drying the coating film of the fine particle dispersion.
Further, the step (B2) may be a step of applying the fine particle dispersion by spin coating, and according to this, the application of the dispersion can be facilitated.

Further, according to another aspect, the electron-emitting device of the present invention may be used in an electron-emitting device. That is, by providing a power supply unit that applies a voltage between the first electrode and the second electrode of the electron-emitting device, a sufficient amount of electron emission can be obtained by applying an appropriate voltage (for example, 10 to 25 V), An electron-emitting device that can stably operate continuously for a long time is configured.
Further, the electron emission apparatus includes main parts such as a self-luminous device, an image display device including the self-luminous device, an ion wind generator capable of cooling an object to be cooled, a charging device, and an image forming apparatus including the charging device. Can be used.

According to the self-luminous device, stable and long-lasting surface light emission can be realized.
Further, according to the ion wind generator, there is no discharge, no generation of harmful substances such as ozone and NO _x , and the use of the slip effect on the surface of the object to be cooled enables the surface of the object to be cooled. Can be cooled with high efficiency.
Further, according to the charging device, without discharge, without causing harmful substances, including ozone and NO _x, it can be charged stably for a long period of time the member to be charged.
Note that these devices including the electron-emitting device may include a plurality of electron-emitting devices. For example, a plurality of electron-emitting devices may be arranged on a plane body and applied to these devices. Further, the first electrode may be shared by a plurality of electron-emitting devices.

  Hereinafter, embodiments and examples of the present invention will be specifically described with reference to the drawings. Note that the embodiments and examples described below are merely specific examples of the present invention, and the present invention is not limited thereto.

Embodiment 1
FIG. 1 is a schematic diagram showing the configuration of the embodiment 1-1 of the electron-emitting device of the present invention.
As shown in FIG. 1, the electron-emitting device 9 according to Embodiment 1-1 has an electron emission having a first electrode 1 and a plurality of small holes 2 a formed on the first electrode 1 and penetrating in the film thickness direction. The electron accelerating layer 3 having the control insulating film 2 and the electron emission controlling insulating film 2 having a film thickness equal to or larger than that and including the insulating fine particles 3 a embedded in the small holes 2 a of the electron emitting controlling insulating film 2. And a carbon thin film 4 formed on the electron acceleration layer 3 and a second electrode 5 formed on the carbon thin film 4.
Further, the electron-emitting device 10 is configured by including the electron-emitting device 9 and a power supply unit 7 that applies a voltage between the first electrode 1 and the second electrode 5 of the electron-emitting device 9. At this time, the first electrode 1 is electrically connected to the negative electrode of the power supply unit 7, and the second electrode 5 is electrically connected to the positive electrode of the power supply unit 7.

<First electrode>
The first electrode 1 is an electrode substrate that also functions as a substrate, and is composed of a plate-like body formed of a conductor.
The first electrode 1 functions not only as a support for the electron-emitting device but also as an electrode. Therefore, the first electrode 1 only needs to have a certain degree of strength and appropriate conductivity. For example, a substrate formed of a metal such as stainless steel (SUS), Al, Ti, or Cu, or a semiconductor substrate such as Si, Ge, or GaAs can be used.

The first electrode 1 may be a structure in which an electrode formed of a conductive film is formed on an insulating substrate such as a glass substrate or a plastic substrate.
For example, when a glass substrate is used, the surface of the glass substrate serving as an interface with the electron acceleration layer 4 is covered with a conductive film using, for example, magnetron sputtering, and the first glass substrate covered with the conductive film is used. It may be used as the electrode 1.
As a material for the conductive film, it is preferable to use a conductive material with high antioxidation power, and more preferable to use a noble metal if stable operation in the atmosphere is desired. For the conductive film, ITO, which is an oxide conductive material and is widely used for transparent electrodes, is also useful.

Moreover, when the 1st electrode 1 is comprised with the electroconductive film which coat | covers an insulator board | substrate, since a toughness is requested | required of an electroconductive film, you may laminate | stack a some electroconductive film.
For example, a Ti film is formed on the surface of a glass substrate with a thickness of 200 nm, a metal laminated film in which a Cu film is formed with a thickness of 1000 nm, or a Mo film is formed on the surface of the glass substrate with a thickness of 30 nm. Although a metal laminated film in which an Al film is formed with a film thickness of 130 nm and a Mo film is formed thereon with a film thickness of 50 nm may be used as the first electrode 1, it is not limited to these materials and values.
When a glass substrate is covered with a Ti thin film and a Cu thin film, a tough conductive thin film can be formed.
Note that the electrode may be formed by patterning the conductive film on the surface of the insulator substrate into a square or the like using a known photolithography or mask.

<Electron emission control insulating film>
The electron emission control insulating film 2 is an insulating film formed on the first electrode 1 and has a function of uniformly controlling the electron emission of the electron-emitting device 9 in the plane by having a plurality of small holes 2a. .
The material and film thickness of the electron emission control insulating film 2, the size, shape and density of the small holes 2a are as described above.

<Electron acceleration layer>
The electron acceleration layer (insulating fine particle layer) 3 includes the insulating fine particles 3a and is formed on the electron emission control insulating film 2 including the small holes 2a. This layer has a function of accelerating electrons from the first electrode 1 toward the second electrode 2.
Since the electron acceleration layer 3 is mainly composed of the insulating fine particles 3a having semiconductivity, a very weak current flows when a voltage is applied.
The voltage-current characteristic of the electron acceleration layer 3 shows a so-called varistor characteristic, and the current value is rapidly increased as the applied voltage increases. A part of this current becomes ballistic electrons due to the strong electric field in the electron acceleration layer 3 formed by the applied voltage, passes through the second electrode 5 and is emitted to the outside of the electron-emitting device 10. Further, ballistic electrons may be emitted to the outside through the gaps (fine holes) of the second electrode 5 resulting from the influence of the irregularities on the surface of the electron acceleration layer 3 by the insulating fine particles 3a.
The formation process of ballistic electrons is presumed to be due to electrons tunneling while being accelerated in the direction of the electric field.
Further, when the insulating fine particles 3a are completely dissolved and crystallized by heat treatment, the electron acceleration layer 3 becomes an insulator and loses the function of accelerating electrons. Therefore, if the insulating fine particles 3a are simply used as a material, Instead, the electron acceleration layer 3 needs to be formed of insulating fine particles 3a that maintain the particle shape.

The film thickness of the electron acceleration layer 3 is preferably 0.008 to 6.0 μm, and preferably 0.3 to 2.0 μm, for example, when the applied voltage to the electron-emitting device 9 and the electron emission control insulating film 2 are in the above conditions. More preferred.
If the electron acceleration layer 3 has a film thickness in the above range, it becomes easy to form the electron acceleration layer 3 having a uniform film thickness (smooth surface), and as a result, a portion of the electron acceleration layer corresponding to each small hole 3a. 3 becomes uniform, and electrons can be emitted more uniformly over the entire electron-emitting device 9.
The electron-emitting device 9 preferably accelerates electrons by applying a strong electric field at as low a voltage as possible. Depending on the voltage applied to the electron-emitting device 9 and the film thickness of the electron emission control insulating film, The film thickness of the acceleration layer 3 is preferably as thin as possible even within the above film thickness range (a range of 0.008 to 6.0 μm or 0.3 to 2.0 μm).
In the present embodiment, the film thickness of the electron acceleration layer refers to the thickness of the electron emission control insulating film (that is, the distance between the first electrode and the second electrode) where the small holes are formed.

As the insulating fine particles 3a, insulating fine particles made of a semiconductor oxide such as SiO ₂ or ZnO or a metal oxide such as Al ₂ O ₃ , TiO ₂ , or CuO can be used. These insulating fine particles can be used alone or in combination of a plurality of types.
When a plurality of types of insulating fine particles 3a of different materials are used, the plurality of types of insulating fine particles 3a may be particles having a particle size in a numerical range described later.
When a plurality of types of insulating fine particles 3a are dispersed in a dispersion liquid and the dispersion liquid is applied onto the electron emission control insulating film 2 to form the electron acceleration layer 4, the selection of the insulating fine particles 3a is performed in the dispersion liquid. It is desirable to consider the dispersibility of the particles.

The particle diameter of the insulating fine particles 3a is preferably 5 to 1000 nm when the film thickness of the electron emission control insulating film 2 and the size of the small holes 2a are the above conditions.
If the particle size of the insulating fine particles 3a is smaller than 5 nm, it is difficult to reduce the variation in particle size, and it is difficult to form the electron acceleration layer 3 having a uniform film thickness. On the other hand, when the particle diameter is larger than 1000 nm, when the electron acceleration layer 3 is formed by applying a dispersion of the insulating fine particles 3a, the insulating fine particles 3a are settled in the dispersion and the dispersibility is deteriorated. As a result, in the coating film of the dispersion liquid, there are likely to be places where there are a lot of insulating fine particles 3a and places where there are few, and it is difficult to form the electron acceleration layer 3 having a uniform film thickness.
In the present invention, “particle size” means an average primary particle size.

<Modification of electron acceleration layer>
In Embodiment 1-1, the electron acceleration layer 3 is composed of only the insulating fine particles 3a, but the electron acceleration layer 3 may be composed of other fine particles and materials.
For example, the electron acceleration layer 3 may include conductive fine particles having a particle size smaller than the particle size of the insulating fine particles 3a.
By adding conductive fine particles to the electron acceleration layer 3, it is possible to control the amount of current value electrons emitted through the electron acceleration layer 3. In other words, the electric resistance value of the electron acceleration layer 3 can be adjusted to an arbitrary range by adjusting the content of the insulating fine particles 3 a in the electron acceleration layer 3.
Although it does not specifically limit as electroconductive fine particles, For example, you may contain at least 1 sort (s) among the electroconductive particles which consist of gold | metal | money, silver, platinum, palladium, and nickel.
If the particle size of the conductive fine particles is equal to or larger than the particle size of the insulating fine particles, the insulating properties required by the electron acceleration layer 3 cannot be obtained. Must be smaller than the diameter.

Furthermore, the electron acceleration layer 3 may contain a small amount of silicone resin as a binder component.
By including the silicone resin in the electron acceleration layer 3, the mechanical strength of the electron-emitting device 9 can be improved, and device deterioration due to oxygen, moisture, etc. in the atmosphere can be prevented, resulting in a longer life. Can be achieved.
Moreover, additives, such as a dispersing agent, may be contained in the electron acceleration layer 3 as needed.
Further, the electron acceleration layer 3 may have a laminated structure of two or more layers made of different materials. For example, it is possible to adopt a laminated structure in which the first layer is a substantial electron acceleration layer, the second layer is a protective layer for the purpose of increasing mechanical strength, dampproofing, and planarizing the film surface.

<Carbon thin film>
The carbon thin film 4 functions as a resistor between the second electrode 5 and the electron acceleration layer 3.
As described above, since the electron emission control insulating film 2 is provided with a plurality of small holes 2a, when the electron-emitting device 9 is subjected to an aging test (for example, a continuous operation test for a long time), each small hole 2a. The state where the electric field is concentrated on the portion continues, and the electron-emitting device 9 is continuously exposed to local voltage / current stress.
When a large voltage / current stress continues for a long time, defects may occur in the peripheral portion of the small hole 2a of the electron emission control insulating film 2, and when the number of defects increases, a current path is generated, leading to dielectric breakdown.
Since the carbon thin film 4 as a resistor has a higher electrical resistance than the second electrode 5 made of, for example, gold, silver or the like, the local and continuous voltage / current stress applied by the electron-emitting device 9 is increased. As a result, defects are less likely to occur and dielectric breakdown is less likely to occur.
As a material of the carbon thin film, for example, graphite is suitable.

  The film thickness of the carbon thin film 4 depends on conditions such as applied voltage, film thickness of the electron emission control insulating film 2, the size and density of the small holes 2a, the material of the second electrode 5, and the like. 5-20 nm is preferable. If the thickness of the carbon thin film is less than 5 nm, it is not sufficient for the carbon thin film to function as a resistor. On the other hand, if the thickness of the carbon thin film is greater than 20 nm, the voltage required for electron emission becomes too large.

  Although Embodiment 1-1 illustrates the case where the carbon thin film 4 is formed on the surface of the electron acceleration layer 3 on the second electrode 5 side, the electron emission device 10y of Embodiment 1-2 shown in FIG. As described above, the carbon thin film 4 may be omitted in the electron-emitting device 9. That is, the electron-emitting device 9 includes a first electrode 1, an electron emission control insulating film 2, an electron acceleration layer 3 including insulating fine particles 3 a, and a second electrode 5 formed on the electron acceleration layer 3. May be provided. In FIG. 2, the same elements as those in FIG. 1 are denoted by the same reference numerals.

<Second electrode>
The second electrode 5 constitutes a pair of electrodes with the first electrode 1 and is an electrode for applying a voltage in the electron acceleration layer 3 together with the first electrode 1. For this reason, what is necessary is just to form with the material which has the electroconductivity of the grade which functions as an electrode.
However, since it is preferable that the second electrode 5 is emitted within the electron acceleration layer 3 by being transmitted through the electron acceleration layer 3 with as little energy loss as possible, it can be formed with a low work function and a thin film. It is preferable to form with an electroconductive material.
Examples of such a material include gold, silver, tungsten, titanium, aluminum, palladium, and the like whose work function corresponds to 4 to 5 eV. In particular, assuming operation at atmospheric pressure, gold without oxide and sulfide formation reaction is the best material. In addition, silver, palladium, tungsten, and the like, which have a relatively small oxide formation reaction, are materials that can withstand actual use without problems.

The film thickness of the second electrode 5 is important as a condition for efficiently emitting electrons from the electron-emitting device 9 to the outside, and from this viewpoint, 10 to 55 nm is preferable.
The minimum film thickness for causing the second electrode 5 to function as a planar electrode is 10 nm, and electrical conduction cannot be ensured with a film thickness smaller than this. On the other hand, the maximum film thickness for emitting electrons from the electron-emitting device 9 to the outside is 55 nm. When the film thickness is thicker than this, no ballistic electrons are transmitted, and the second electrode 5 absorbs or reflects ballistic electrons. Recapture into the acceleration layer 3 occurs. For this reason, the film thickness of the second electrode 5 is preferably 10 to 55 nm.

<Production method>
Next, a method for manufacturing the electron-emitting device 9 according to Embodiment 1 will be described with reference to FIG.
The electron-emitting device 9 configured as described above includes a step of forming an electron emission control insulating film 2 having a plurality of small holes 2a penetrating in the film thickness direction on the first electrode 1, and an electron emission control insulating film A step of forming an electron acceleration layer 3 including insulating fine particles 3 a on the first electrode 1 so as to cover 2; a step of forming a carbon thin film 4 on the electron acceleration layer 3; It is manufactured by a method for manufacturing an electron-emitting device including a step of forming two electrodes 5.

More specifically, in the step of forming the electron emission control insulating film 2, first, a coating solution in which an acrylic resin as an insulating material is dissolved in a solvent is applied onto the first electrode 1 by a spin coating method. The coating film is heated and dried, and then a plurality of small holes 2a are formed in the dried coating film (insulating film) by photolithography to form the electron emission control insulating film 2. For example, as described above, the small hole 2a having an inner diameter of 21.2 to 141.4 μm is formed in the electron emission control insulating film 2 having a thickness of 0.1 to 3 μm.
Examples of the insulator material include organic polymers such as silicone resins, polyimide resins, epoxy resins, polyester resins, polyurethane resins, and polystyrene resins, in addition to acrylic resins. Moreover, you may use these organic polymers 1 type or in mixture of 2 or more types.
In addition to the organic polymer, the insulator material is an inorganic material such as silicon oxide or silicon nitride, and the electron emission control insulating film 2 is formed by, for example, sputtering, vapor deposition, CVD, or the like. Also good.
Moreover, as a method of the small holes 2a, electron beam lithography, plasma etching, ink jet, or the like may be used, and the method is not limited to these methods.

Next, in the step of forming the electron acceleration layer 3, first, an insulating fine particle dispersion in which the insulating fine particles 3a are dispersed in a solvent is prepared. At this time, conductive fine particles and a binder component may be mixed in the insulating fine particle dispersion.
The solvent used in the insulating fine particle dispersion is not particularly limited as long as the binder component can be dissolved, the insulating fine particles 3a and the conductive fine particles can be dispersed, and can be dried after coating. For example, toluene, benzene, Xylene, hexane, tetradecane and the like can be used.
The concentration of the insulating fine particles 3a in the insulating fine particle dispersion is preferably 10 to 50% by weight. If the concentration is lower than 10% by weight, it is difficult to fully fill the small particles 2a of the electron emission control insulating film 2 with the insulating fine particles 3a. If the concentration is higher than 50% by weight, the viscosity of the insulating fine particle dispersion is low. As it rises and agglomeration occurs, the thinned electron acceleration layer 3 cannot be formed.

Next, the insulating fine particle dispersion is applied onto the first electrode 1 by spin coating.
The spin coating conditions are not particularly limited. For example, the first electrode 1 having the coating film of the insulating fine particle dispersion is rotated at a spin rotation speed of 500 rpm for 1 second, and then rotated at a spin rotation speed of 3000 rpm for 10 seconds.
The coating amount of the coating film on the first electrode 1 is not particularly limited. For example, when the coating film is applied to a 24 mm square first electrode 1, it may be 0.2 mL / cm ² or more.
By using the spin coating method, the insulating fine particles and conductive fine particles can be easily applied over a wide range.
Subsequently, the coating film on the first electrode 1 is dried to form the electron acceleration layer 3. The application and drying may be repeated until the electron acceleration layer 3 has a desired film thickness.

Next, in the process of forming the carbon thin film 4, the carbon thin film 4 is formed on the electron acceleration layer 3 by using, for example, vapor deposition or magnetron sputtering.
Subsequently, in the step of forming the second electrode 5, the second electrode 5 is formed on the carbon thin film 4 by using, for example, a magnetron sputtering method, an ink jet method, a spin coating method, a vapor deposition method, or the like, and the electron-emitting device 9. Is completed.
Then, the negative electrode and the positive electrode of the power supply unit 7 are electrically connected to the first electrode 1 and the second electrode 5 of the electron-emitting device 9 through lead wires, whereby the electron-emitting device 10 is completed.
As the power supply unit 7, a power supply capable of applying a voltage of 10 to 25V can be used.

FIG. 3 is a schematic diagram showing an experimental system for confirming an electron emission point using the electron-emitting device 9 of Embodiment 1-1 described in FIG.
An experiment for confirming an electron emission point using this experimental system will be described in an example described later.

[Embodiment 2]
FIG. 4 is a schematic diagram illustrating an example of a charging device using the electron-emitting device of Embodiment 1 (Embodiments 1-1 to 1-2). In FIG. 4, elements similar to those in FIG. 1 are denoted by the same reference numerals.
The charging device 90 is composed of an electron emitting device 10 having an electron emitting element 9 and a power supply unit 7 for applying a voltage thereto, and charges the photosensitive member P provided in the electrophotographic image forming apparatus. is there.

The electron-emitting device 9 constituting the charging device 90 is installed to face the photosensitive member P that is a member to be charged, and emits electrons when a voltage is applied to charge the photosensitive member P. In the image forming apparatus described in this embodiment, conventionally known members can be used as the constituent members other than the charging device 90.
Here, it is preferable that the electron-emitting device 9 used as the charging device 90 is disposed 3 to 5 mm away from the photoreceptor P, for example.
The applied voltage to the electron-emitting device 9 is preferably about 25 V, and the electron acceleration layer 3 in the electron-emitting device 9 emits 1 μA / cm ² electrons per unit time by applying a voltage of 25 V, for example. It only has to be configured.

The electron emission device 10 used as the charging device 90 does not discharge even when operated in the atmosphere, and therefore, no ozone is generated from the charging device 90.
Ozone is harmful to the human body and is regulated by various environmental standards, and even if it is not released outside the machine, it oxidizes and degrades organic materials inside the machine, such as the photoreceptor P and belt.
Such a problem does not occur because the image forming apparatus has such a charging device 90.
Further, since the electron emission element 9 has an improved electron emission amount, the photosensitive member P can be efficiently charged by the charging device 90.
Further, by using the electron emitting device 10 in which a plurality of the electron emitting elements 9 are formed on the same substrate as the charging device 90, the charging device 90 is configured as a surface electron source. Therefore, it is possible to earn a lot of opportunities for charging a portion of the photosensitive member P.
Therefore, the charging device 90 can be uniformly charged as compared with a wire charger that charges in a linear manner. Further, the charging device 90 has an advantage that the applied voltage can be remarkably reduced to about 10 V as compared with a corona discharger that requires voltage application of several kV.

[Embodiment 3]
FIG. 5 is a schematic view showing the self-luminous device of Embodiment 3-1 using the electron-emitting device of Embodiment 1, and FIG. 6 is the self-luminous light of Embodiment 3-2 using the electron-emitting device of Embodiment 1. FIG. 7 is a schematic diagram showing the self-luminous device of Embodiment 3-3 using another electron-emitting device, and FIG. 8 is a schematic diagram showing the self-luminous device of Embodiment 3-3. It is a schematic diagram which shows the image display apparatus of Embodiment 3-4. 5 to 8, the same elements as those in FIG. 1 are denoted by the same reference numerals.

A self-luminous device 31 shown in FIG. 5 (Embodiment 3-1) has an electron-emitting device 10 having an electron-emitting device 9 and a power supply unit 7 that applies a voltage to the electron-emitting device 9, and is opposed to the electron-emitting device 9. And a light emitting unit 36 to be arranged.
The light emitting unit 36 has a laminated structure in which an ITO film 33 and a phosphor layer 32 are laminated in this order on a glass substrate 34 serving as a base material, and the phosphor layer 32 faces the second electrode 5 of the electron-emitting device 9. doing.
The film thickness of the ITO film 33 may be a film thickness that can ensure conductivity, and may be, for example, 100 to 300 nm, and is 150 nm in this embodiment.

As the phosphor layer 32, an electron excitation type phosphor material corresponding to red, green, and blue light emission is suitable. For example, in red, Y ₂ O ₃ : Eu, (Y, Gd) BO ₃ : Eu, green In this case, Zn ₂ SiO ₄ : Mn, BaAl ₁₂ O ₁₉ : Mn, and in blue, BaMgAl ₁₀ O ₁₇ : Eu ²⁺ can be used.
The thickness of the phosphor layer 32 is preferably about 1 μm.
In forming the phosphor layer 32, the phosphor layer 32 can be formed by a known technique such as a bar coater method, a dropping method, or a spin coating method using a kneaded product of an epoxy resin serving as a binder and phosphor fine particles.
At this time, phosphor particles of one or more colors are selected at an appropriate weight mixing ratio from among red, green and blue phosphor particles so that a desired emission color can be obtained. For example, if a white emission color is to be obtained, a kneaded material in which red, green and blue phosphor fine particles are mixed at a weight mixing ratio of 1: 1: 1 is used.

Here, in order to increase the light emission luminance of the phosphor layer 32, it is necessary to accelerate the electrons emitted from the electron-emitting device 9 toward the phosphor layer 32. In this case, the first electrode of the electron-emitting device 9 is used. It is preferable that a second power supply unit 35 for applying a DC voltage for forming an electric field for accelerating electrons is provided between 1 and the ITO film 33.
At this time, the distance between the phosphor layer 32 and the electron-emitting device 9 is set to 0.3 to 1 mm, the applied voltage from the power supply unit 7 is set to 18V, and the applied voltage from the second power supply unit 35 is set to 500 to 2000V. preferable.

A self-luminous device 131 shown in FIG. 6 (Embodiment 3-2) includes an electron-emitting device 9 having an electron-emitting device 9 and a power supply unit 7 that applies a voltage to the electron-emitting device 9, and a phosphor formed on the electron-emitting device 9. Layer 132.
The phosphor layer 132 can be formed on the second electrode 5 of the electron-emitting device 9 by the same method as in Embodiment 3-1. However, since the electron-emitting device 9 is weak against external force and the bar-coater method may be used, the electron-emitting device 9 may be broken. Therefore, it is preferable to use a dropping method or a spin coating method.

A self-luminous device 231 shown in FIG. 7 (Embodiment 3-3) is an electron-emitting device 210 having an electron-emitting device 29 different from the above and a power supply unit 7 that applies a voltage to the electron-emitting device 29.
In the electron-emitting device 29, the electron acceleration layer 23 is formed of a material using a material in which the insulating fine particles 3a and phosphor fine particles (reference numerals are omitted) are mixed.
The phosphor fine particles generally have a low electric resistance, and the electric resistance is clearly lower than that of the insulating fine particles 3a.
Therefore, when using phosphor fine particles, it is necessary to suppress the amount of phosphor fine particles mixed with the insulating fine particles 3a to a small amount. For example, when spherical silica particles (particle diameter: 110 nm) are used as the insulating fine particles 3a and ZnS: Mg (particle diameter: 500 nm) are used as the phosphor fine particles, a weight mixing ratio of about 3: 1 is appropriate.
In this case, one or more phosphor fine particles are selected at an appropriate weight mixing ratio from among red, green and blue phosphor fine particles so that a desired emission color can be obtained in the total amount of the phosphor fine particles.

In the case of the self-luminous device 31 of Embodiment 3-1, the phosphor layer 32 emits light when electrons emitted from the electron-emitting device 9 collide with the phosphor layer 32 of the light emitting unit 36.
In the case of the self-luminous device 131 of Embodiment 3-2, the phosphor layer 132 emits light when electrons enter and collide with the phosphor layer 132 from the electron emitter 9.
In the case of the self-luminous device 231 of Embodiment 3-3, when the electrons from the first electrode 1 pass through the electron acceleration layer 23, the electrons collide with the phosphor fine particles, whereby the electron-emitting device 29 emits light.
Since these electron-emitting devices 9 and 29 have improved electron emission amounts, the self-emitting devices 31, 131, and 231 can emit light efficiently.
In addition, although the self-light-emitting devices 31, 131, and 231 can be operated in the atmosphere, the electron emission current is increased by vacuum sealing, and light can be emitted more efficiently.

An image display apparatus 340 illustrated in FIG. 8 (Embodiment 3-4) includes the self-light-emitting device 231 illustrated in FIG.
In the image display device 340, the self light emitting device 231 is disposed behind the liquid crystal panel 330 and used as a backlight.
Therefore, in this case, red, green, and blue phosphor fine particles are dispersed in a weight mixing ratio of 1: 1: 1 in the electron acceleration layer 23 so that the white light emitting device 231 can obtain a white emission color.
In this case, for example, the voltage applied to the self-light emitting device 231 is preferably set to 20 to 35 V so that the self-light emitting device 231 emits 10 μA / cm ² of electrons per unit time. The distance from the liquid crystal panel 330 is preferably about 0.1 mm.
The liquid crystal panel 330 is a conventionally known one, for example, from the backlight side, a polarizing plate, a glass substrate, a transparent electrode, an alignment film, a liquid crystal, an alignment film, a transparent electrode, a protective film, a color filter, a glass substrate, and a polarizing plate. A laminated panel structure can be used.

Further, as an image display apparatus of Embodiment 3-5 (not shown), the self-luminous devices 31 described in FIG. 5 (Embodiment 3-1) are arranged in a matrix, and a field emission display (FED) by the self-luminous device 31 itself is arranged. : Field Emission Display) Images can also be displayed.
In this case, for example, it is preferable to set the applied voltage to the self light emitting device 31 to 20 to 35 V so that the self light emitting device 31 emits 10 μA / cm ² of electrons per unit time.

[Embodiment 4]
FIG. 9 is a schematic diagram showing the ion wind generator of Embodiment 4-1 using the electron-emitting device of Embodiment 1, and FIG. 10 shows ions of Embodiment 4-2 using the electron-emitting device of Embodiment 1. It is a schematic diagram which shows a wind generator. In FIG. 9 and FIG. 10, the same reference numerals are given to the same elements as those in FIG.
The ion wind generator 150 of FIG. 9 (Embodiment 4-1) includes an electron emitter 10 having an electron emitter 9 and a power supply unit 7 that applies a voltage to the electron emitter 9.
The ion wind generator 150 is arranged so that the electron-emitting device 9 faces the object to be cooled Q in an inclined manner, and the electrons are directed toward the object Q to be cooled with the electron-emitting device 9 electrically grounded. To cool the object Q to be cooled by generating ion wind.

In other words, conventionally, even if air is sent to the surface of the object Q to be cooled only with a fan, a so-called “no-slip effect” occurs in which the air molecules closest to the surface stay and do not move. The cooling effect of was low.
According to the ion wind generator 150 of Embodiment 4-1, the electrons from the electron-emitting device 9 collide with air molecules to generate ions, and further, the ions collide with surrounding air molecules, thereby causing air molecules and ions. Move. This generates “ionic wind”. At this time, the ions are transported to the surface of the cooled object Q by a potential difference or an electric field, and hot molecules and cold ions are exchanged by an electric field (image force) acting between the cooled object Q. The surface is cooled.
In this case, for example, the voltage applied to the electron emitter 9 is preferably set to about 18 V so that the ion wind generator 150 emits 1 μA / cm ² of electrons per unit time.
In addition, as the to-be-cooled body Q, electronic parts, such as a semiconductor, CPU of a computer, and LED, the apparatus which mounts them, etc. are mentioned, for example.

The ion wind generator 160 of FIG. 10 (Embodiment 4-2) is provided rotatably around the electron-emitting device 9 and the electron-emitting device 10 having the electron-emitting device 9 and the power supply unit 7 that applies a voltage to the device. The air blowing fan 42 is provided.
The ion wind generator 160 is also arranged so that the electron-emitting device 9 is inclined with respect to the cooled object Q, and the electrons are directed toward the cooled object Q with the electron-emitting device 9 electrically grounded. In addition, the blower fan 42 blows air toward the cooled object Q, thereby generating ion wind and air flow to cool the cooled object Q.

At this time, an air flow is generated in addition to the ion wind, so the atmosphere (air) in the vicinity of the surface of the cooled object Q can be efficiently replaced, and the cooling efficiency is greatly improved by the synergistic effect of the ion wind and the air flow. To do.
In this case, for example, the voltage applied to the electron emitter 9 is set to about 18 V so that the ion wind generator 160 emits 1 μA / cm ² of electrons per unit time, and the air volume by the blower fan 42 is set to 0. it is preferably set to 9～2L / min / cm ^2.

[Other Embodiments]
In the first to fourth embodiments, the case where the film thickness of the electron acceleration layer 3 is thicker than the film thickness of the electron emission suppression insulating layer 2 is exemplified, but the film thickness of the electron acceleration layer 3 is the film thickness of the electron emission suppression insulation layer 2. Or thin (not shown).
In the former case, the carbon thin film 4 and the second electrode 5 are formed on the surface of the electron emission suppressing insulating layer 2 and on the surface of the electron acceleration layer 3 filled in each small hole 2a.
In the latter case, since the surface of the electron acceleration layer 3 is concavely lower than the surface of the electron emission suppression insulating layer 2, the electron acceleration layer 3 on the surface of the electron emission suppression insulating layer 2 and in each small hole 2a thereof. When the carbon thin film 4 and the second electrode 5 are formed on the surface, a recess is formed at a position corresponding to each electron acceleration layer 3 in the second electrode 5.

In the following examples, an experiment in which current measurement is performed using the electron-emitting device according to the present invention will be described. In addition, this Example is an example, Comprising: The content of this invention is not restrict | limited.
First, the electron-emitting devices of Examples 1 and 2 and the electron-emitting devices of Comparative Examples 1 and 2 were produced as follows. Examples 1 and 2 are electron-emitting devices having the same structure as in FIG. 1, and Comparative Examples 1 and 2 are electron-emitting devices in which the electron emission control insulating film 2 and the carbon thin film 4 in FIG. 1 are omitted.
And about each produced electron-emitting device, the experiment system shown in FIG. 3 was arrange ^| positioned in the vacuum container of 1 * 10 <^-8> ATM, and the confirmation experiment of the electron emission point was conducted.

  In the experimental system of FIG. 3, the light emitting portion 36 is disposed on the second electrode 5 side of the electron-emitting device 9 through the insulating spacer 8 so as to face each other. The first electrode 1 and the second electrode 5 of the electron-emitting device 9 are connected to the DC power supply unit 7A, and the light emitting unit 36 is connected to the DC power supply unit 7B. The distance between the electron-emitting device 9 and the phosphor layer 32 was set to 5 mm.

Example 1
A 24 mm × 24 mm square MAM (Mo / Al / Mo) glass substrate is used as the first electrode 1, and 289 small holes 2 a of 60 μm square (diagonal: 84.9 μm) are formed on the first electrode 1 (= 17). X17) An electron emission control insulating film 2 made of an acrylic resin arranged uniformly was produced. (The film thickness of the electron emission control insulating film 2 was 2.5 μm.)
The total area of the small holes 2a is 0.01 cm ² .

Further, 0.6 g of hexane as a solvent and 0.1 g of spherical silica particles having a particle diameter of 50 nm as the insulating fine particles 3a are put into a 5 mL reagent bottle, and the fine particles in the reagent bottle are collected using an ultrasonic disperser. Dispersion was performed to prepare an insulating fine particle dispersion. Then, 0.024 g of silver nanoparticles (manufactured by Applied Nanoparticles Laboratory, silver fine particle size 10 nm) is added to the obtained insulating fine particle dispersion, and the fine particles in the reagent bottle are removed using an ultrasonic disperser. Dispersed to prepare a dispersion A of insulating fine particles and silver nanoparticles.
Next, 0.6 g of hexane as a solvent and 0.1 g of spherical silica particles having a particle size of 50 nm as the insulating fine particles 3a are put into a 5 mL reagent bottle, and the fine particles in the reagent bottle are used with an ultrasonic disperser. Was dispersed to prepare an insulating fine particle dispersion. Then, 0.02 g of a silicone resin (SR2411, manufactured by Toray Dow Corning Co., Ltd.) is added to the obtained insulating fine particle dispersion, and the fine particles in the reagent bottle are dispersed using an ultrasonic disperser. A dispersion B of fine particles and silicone resin was prepared.

Next, the dispersion A is dropped on the electron emission control insulating film 2, and spin coating is performed in two stages under conditions of 500 rpm for 1 second and then 3000 rpm for 10 seconds, so that insulating fine particles and conductive fine particles are obtained. A coating film including the same was formed, and this coating film was dried at 150 ° C. for 60 seconds using a hot plate to form an electron acceleration layer I having a thickness of 1.0 μm. In order not to cause a change with time, the process immediately moved to the next step.
The dispersion liquid B is dropped on the electron acceleration layer I, and spin coating is performed in two stages under conditions of 500 rpm for 1 second and then 3000 rpm for 10 seconds to form a coating film containing insulating fine particles and a silicone resin. The coating film is dried at 200 ° C. for 90 seconds using a hot plate to form an electron acceleration layer II having a film thickness of 1.5 μm, whereby the electron acceleration layer I and the electron acceleration layer II are laminated. An electron acceleration layer 3 having a thickness of 2.5 μm was formed.

Subsequently, a carbon thin film 4 having a film thickness of 10 nm made of graphite was formed on the electron acceleration layer 3 using a vacuum deposition apparatus.
Thereafter, the second electrode 5 having a film thickness of 40 nm and the same area of 0.16 cm ^{2 made} of Au—Pd is formed on the carbon thin film 4 by using a magnetron sputtering apparatus, whereby the electron emission of Example 1 is performed. Element 9 was obtained.
In the electron-emitting device 9 of Example 1, since the film thickness of the electron acceleration layer 3 is 2.5 μm, the inner diameter (the length of the diagonal line) of the small hole 2a is relative to the film thickness of the electron acceleration layer 3. The size was about 33.9 times.

On this electron-emitting device 9, the phosphor layer 32 is arranged oppositely while maintaining a distance of 5 mm by an insulating spacer S to complete the experimental system of FIG. 3, which is a vacuum vessel of 1 × 10 ⁻⁸ ATM. Installed inside. An experiment for confirming the electron emission point in the electron-emitting device 9 was performed, and the results are shown in FIGS. Here, in FIG. 12, the scale bar has a length of 1.0 mm, and the portion surrounded by a dotted line indicates the electron emission effective range of the electron-emitting device 9. (Hereinafter, also in FIGS. 13 to 18, 20, and 22, the scale bar indicates a length of 1.0 mm, and the portion surrounded by the dotted line indicates the effective electron emission range of the electron emitter 9). )
In addition, the applied voltage V1 at this time was 16V, and V2 was 3.5 kV.
As shown in FIGS. 11 and 12, the electron emission points of Example 1 existed uniformly throughout the device.

(Example 2)
A 24 mm × 24 mm square MAM (Mo / Al / Mo) glass substrate is used as the first electrode 1, and 289 small holes 2 a of 60 μm square (diagonal: 84.9 μm) are formed on the first electrode 1 (= 17). X17) An electron emission control insulating film 2 made of an acrylic resin arranged uniformly was produced. (The film thickness of the electron emission control insulating film 2 was 2.5 μm.)
The total area of the small holes 2a is 0.01 cm ² .

Further, in a 20 mL reagent bottle, 3.0 g of hexane as a solvent, 0.5 g of spherical silica particles having a particle size of 50 nm as insulating fine particles 3a, silver nanoparticles (manufactured by Applied Nanoparticles Laboratory, particle size of silver fine particles) 10 nm) 0.12 g was added, and the fine particles in the reagent bottle were dispersed using an ultrasonic disperser to prepare a dispersion of insulating fine particles and silver nanoparticles.
Next, 0.175 g of a silicone resin (SR2411 manufactured by Toray Dow Corning Co., Ltd.) is added to the obtained dispersion liquid of insulating fine particles and silver nanoparticles, and the fine particles in the reagent bottle are used with an ultrasonic disperser. Was dispersed to prepare dispersion C of insulating fine particles, silver nanoparticles and silicone resin.

  Next, the dispersion C is dropped on the electron emission control insulating film 2 and spin coating is performed in two stages under conditions of 500 rpm for 1 second and then 3000 rpm for 10 seconds, so that insulating fine particles, conductive fine particles, and silicone are applied. A coating film containing a resin was formed, and this coating film was dried at 150 ° C. for 60 seconds using a hot plate to form an electron acceleration layer I having a thickness of 1.0 μm.

Subsequently, a carbon thin film 4 having a film thickness of 10 nm made of graphite was formed on the electron acceleration layer 3 using a vacuum deposition apparatus.
Thereafter, by using a magnetron sputtering apparatus, a second electrode 5 having a film thickness of 40 nm and an area of 0.16 cm ^{2 made} of Au—Pd is formed on the carbon thin film 4, thereby emitting electrons in the second embodiment. Element 9 was obtained.
In the electron-emitting device 9 of Example 2, since the film thickness of the electron acceleration layer 3 is 1.0 μm, the inner diameter (the length of the diagonal line) of the small hole 2a is relative to the film thickness of the electron acceleration layer 3. The size was about 84.9 times.

On this electron-emitting device 9, the phosphor layer 32 is arranged oppositely while maintaining a distance of 5 mm by an insulating spacer S to complete the experimental system of FIG. 3, which is a vacuum vessel of 1 × 10 ⁻⁸ ATM. Installed inside. And the confirmation experiment of the electron emission point in the electron-emitting device 9 was conducted, and the result is shown in FIG. In addition, the applied voltage V1 at this time was 16V, and V2 was 3.5 kV.
As shown in FIG. 13, the electron emission points of Example 2 existed uniformly throughout the entire device.
Further, an electron-emitting device 9 having a film thickness of 0.3 μm of the electron acceleration layer I was produced in the same manner as above except that the dispersion C was diluted, and an experiment for confirming the electron emission point was performed. Met. (In this case, the inner diameter (the length of the diagonal line) of the small hole 2a was about 282.8 times (approximately 300 times) the film thickness of the electron acceleration layer 3.

(Example 3)
A 24 mm × 24 mm square MAM (Mo / Al / Mo) glass substrate is used as the first electrode 1, and 289 small holes 2 a of 60 μm square (diagonal: 84.9 μm) are formed on the first electrode 1 (= 17). X17) An electron emission control insulating film 2 made of an acrylic resin arranged uniformly was produced. (The film thickness of the electron emission control insulating film 2 was 2.5 μm.)
The total area of the small holes 2a is 0.01 cm ² .

Next, the dispersion C prepared in Example 2 is dropped on the electron emission control insulating film 2, and spin coating is performed in two stages under conditions of 500 rpm for 1 second and then 3000 rpm for 10 seconds, so that insulating fine particles are formed. A coating film containing conductive fine particles and a silicone resin was formed, and this coating film was dried at 150 ° C. for 60 seconds using a hot plate, thereby forming an electron acceleration layer I having a thickness of 1.0 μm.
In order not to cause a change with time, the process immediately moved to the next step.
The dispersion C is further dropped on the electron acceleration layer I, and the same spin coating and drying operations as described above are repeated again to form an electron acceleration layer II having a film thickness of 1.0 μm. An electron acceleration layer 3 having a film thickness of 2.0 μm and laminated with the acceleration layer II was formed.

Then, the carbon thin film 4 and the 2nd electrode 5 were formed similarly to Example 2, and the electron-emitting element 9 of Example 3 was obtained.
In the electron-emitting device 9 of Example 3, since the electron acceleration layer 3 has a thickness of 2.0 μm, the inner diameter (the length of the diagonal line) of the small hole 2 a is set to the thickness of the electron acceleration layer 3. The size was about 42.4 times.

FIG. 14 shows the result of an experiment for confirming the electron emission point in a vacuum of 1 × 10 ⁻⁸ ATM using the electron-emitting device 9 of Example 3. In addition, the applied voltage V1 at this time was 16V, and V2 was 3.5 kV.
As shown in FIG. 14, the electron emission points of Example 3 existed uniformly throughout the entire device.

Example 4
A 24 mm × 24 mm square MAM (Mo / Al / Mo) glass substrate is used as the first electrode 1, and 289 small holes 2 a of 60 μm square (diagonal: 84.9 μm) are formed on the first electrode 1 (= 17). X17) An electron emission control insulating film 2 made of an acrylic resin arranged uniformly was produced. (The film thickness of the electron emission control insulating film 2 was 2.5 μm.)
The total area of the small holes 2a is 0.01 cm ² .

Next, the dispersion C prepared in Example 2 is dropped on the electron emission control insulating film 2, and spin coating is performed in two stages under conditions of 500 rpm for 1 second and then 3000 rpm for 10 seconds, so that insulating fine particles are formed. A coating film containing conductive fine particles and a silicone resin was formed, and this coating film was dried at 150 ° C. for 60 seconds using a hot plate, thereby forming an electron acceleration layer I having a thickness of 1.0 μm.
In order not to cause a change with time, the process immediately moved to the next step.
The dispersion C is further dropped on the electron acceleration layer I, and the spin coating and drying operations similar to those described above are repeated three times to obtain a 1.0 μm thick electron acceleration layer II and a 1.0 μm thick electron acceleration layer III. An electron acceleration layer IV having a thickness of 1.0 μm was formed. Thereby, an electron acceleration layer 3 having a thickness of 4.0 μm in which the electron acceleration layer I to the electron acceleration layer IV were laminated was formed.

Then, the carbon thin film 4 and the 2nd electrode 5 were formed similarly to Example 2, and the electron-emitting element 9 of Example 4 was obtained.
In the electron-emitting device 9 of Example 4, since the film thickness of the electron acceleration layer 3 is 4.0 μm, the inner diameter (the length of the diagonal line) of the small hole 2 a is relative to the film thickness of the electron acceleration layer 3. The size was about 21.2 times.

FIG. 15 shows the result of an experiment for confirming the electron emission point in a vacuum of 1 × 10 ⁻⁸ ATM using the electron-emitting device 9 of Example 4. In addition, the applied voltage V1 at this time was 20V, and V2 was 3.5 kV.
As shown in FIG. 15, the electron emission points of Example 4 were concentrated in part inside the device.

(Example 5)
A 24 mm × 24 mm square MAM (Mo / Al / Mo) glass substrate is used as the first electrode 1, and 289 small holes 2 a of 60 μm square (diagonal: 84.9 μm) are formed on the first electrode 1 (= 17). X17) An electron emission control insulating film 2 made of an acrylic resin arranged uniformly was produced. (The film thickness of the electron emission control insulating film 2 was 2.5 μm.)
The total area of the small holes 2a is 0.01 cm ² .

Next, the dispersion C prepared in Example 2 is dropped on the electron emission control insulating film 2, and spin coating is performed in two stages under conditions of 500 rpm for 1 second and then 3000 rpm for 10 seconds, so that insulating fine particles are formed. A coating film containing conductive fine particles and a silicone resin was formed, and this coating film was dried at 150 ° C. for 60 seconds using a hot plate, thereby forming an electron acceleration layer I having a thickness of 1.0 μm.
In order not to cause a change with time, the process immediately moved to the next step.
The dispersion C is further dropped on the electron acceleration layer I, and the spin coating and drying operations similar to those described above are repeated five times to obtain an electron acceleration layer II having a thickness of 1.0 μm and an electron acceleration layer III having a thickness of 1.0 μm. An electron acceleration layer IV having a thickness of 1.0 μm, an electron acceleration layer V having a thickness of 1.0 μm, and an electron acceleration layer VI having a thickness of 1.0 μm were formed. Thereby, an electron acceleration layer 3 having a film thickness of 6.0 μm in which the electron acceleration layer I to the electron acceleration layer VI were laminated was formed.

Then, the carbon thin film 4 and the 2nd electrode 5 were formed similarly to Example 2, and the electron-emitting element 9 of Example 5 was obtained.
In the electron-emitting device 9 of Example 5, the film thickness of the electron acceleration layer 3 is 6.0 μm. Therefore, the inner diameter (the length of the diagonal line) of the small hole 2 a is relative to the film thickness of the electron acceleration layer 3. The size was about 14.1 times.

FIG. 16 shows the result of an experiment for confirming the electron emission point in a vacuum of 1 × 10 ⁻⁸ ATM using the electron-emitting device 9 of Example 5. At this time, the applied voltage V1 was 30 V, and V2 was 3.5 kV.
As shown in FIG. 16, the electron emission points of Example 5 were concentrated partially within the device.

(Example 6)
A 24 mm × 24 mm square MAM (Mo / Al / Mo) glass substrate is used as the first electrode 1, and 100 small holes 2 a of 100 μm square (diagonal: 141.4 μm) are formed on the first electrode 1 (= 10 Example 10 in the same manner as in Example 1 except that the electron emission control insulating film 2 (total area of the small holes 2a is 0.01 cm ² ) made of uniformly arranged acrylic resin is formed. Six electron-emitting devices 9 were formed. (The inner diameter (diagonal length) of the small hole 2a of Example 6 was about 56.6 times as large as the film thickness of the electron acceleration layer 3.)

FIG. 17 shows the result of an experiment for confirming the electron emission point in a vacuum of 1 × 10 ⁻⁸ ATM using the electron-emitting device 9 of Example 6. In addition, the applied voltage V1 at this time was 16V, and V2 was 3.5 kV.
As shown in FIG. 17, the electron emission points of Example 2 existed uniformly throughout the entire device.

(Example 7)
A 24 mm × 24 mm square MAM (Mo / Al / Mo) glass substrate is used as the first electrode 1, and 4356 (= 66) small holes 2 a of 15 μm square (diagonal: 21.2 μm) are formed on the first electrode 1. × 66) The same as in Example 1 except that the electron emission control insulating film 2 (total area of the small holes 2a is 0.01 cm ² ) made of an acrylic resin arranged uniformly is formed. An electron-emitting device 9 was formed. (The inner diameter (diagonal length) of the small hole 2a of Example 7 was about 8.5 times as large as the film thickness of the electron acceleration layer 3.)

FIG. 18 shows the result of an experiment for confirming the electron emission point in a vacuum of 1 × 10 ⁻⁸ ATM using the electron-emitting device 9 of Example 7. At this time, the applied voltage V1 was 30 V, and V2 was 3.5 kV.
As shown in FIG. 18, the electron emission points of Example 2 existed uniformly throughout the entire device.

(Comparative Example 1)
An aluminum substrate having a diameter of 24 mm was used as the first electrode 1 and UV irradiation was performed for 10 minutes under a vacuum degree of 20 Pa.
Next, 40% by weight of colloidal silica MP1040 (manufacturer nominal particle diameter 100 nm) manufactured by Nissan Chemical Industries, Ltd. as insulating fine particles is diluted to 10% by weight with ultrapure water, and the fine particles are dispersed with an ultrasonic disperser. A fine particle dispersion was prepared.
Next, 1 mL of the fine particle dispersion is dropped on the first electrode 1 and spin coating is performed in two stages under conditions of 500 rpm for 5 seconds and then 3000 rpm for 10 seconds to form an electron acceleration layer containing insulating fine particles. The film was formed with a thickness of 0.8 μm and was naturally dried at room temperature.

Next, on the electron acceleration layer obtained as described above, by using a magnetron sputtering apparatus, a second electrode having a film thickness of 40 nm and an area of 0.01 cm ^{2 made} of Au-Pd is formed. An electron-emitting device of Comparative Example 1 was obtained.
On this electron-emitting device, the phosphor layer 32 was arranged oppositely while maintaining a distance of 3 mm by an insulating spacer to complete an experimental system, which was placed in a vacuum vessel of 1 × 10 ⁻⁸ ATM. An experiment for confirming the electron emission point in the electron-emitting device was performed, and the results are shown in FIGS. At this time, the applied voltage V1 was 20V, and V2 was 1.5 kV.
As shown in FIGS. 19 and 20, the electron emission points of Comparative Example 1 were concentrated at one point inside the device.

(Comparative Example 2)
First, in a 5 mL reagent bottle, 3.0 g of toluene as a solvent and 0.03 g of Ajisper PB-821 (manufactured by Ajinomoto Fine Techno Co., Ltd.) as a dispersing agent are charged, and the reagent bottle is set in an ultrasonic disperser. A dispersion was prepared. Then, 0.25 g of spherical silica particles having a particle diameter of 50 nm were added as insulating fine particles to this dispersion, and the fine particles in the reagent bottle were dispersed using an ultrasonic disperser to prepare an insulating fine particle dispersion.

Next, the insulating fine particle dispersion is dropped onto a 24 mm × 24 mm square ITO glass substrate as the first electrode 1, and a two-step spin coating is performed at 500 rpm for 1 second and then at 3000 rpm for 10 seconds. In this way, an electron acceleration layer containing insulating fine particles was formed, and this was repeated a total of three times to form an electron acceleration layer having a total film thickness of 0.6 μm.
Next, a second electrode having a thickness of 40 nm and an area of 0.04 cm ^{2 made} of Au—Pd is formed on the electron acceleration layer by using a magnetron sputtering apparatus, so that the electron-emitting device of Comparative Example 2 is obtained. Obtained.

On this electron-emitting device, a phosphor layer 32 is arranged facing each other with a distance of 0.5 mm by an insulating spacer to complete an experimental system, which is installed in a vacuum vessel of 1 × 10 ⁻⁸ ATM. did. Then, an experiment for confirming the electron emission point in the electron-emitting device was performed, and the results are shown in FIGS. At this time, the applied voltage V1 was 20V, and V2 was 1.5 kV.
As shown in FIGS. 21 and 22, the electron emission points of Comparative Example 2 were concentrated at two points, one at each corner of the device.

From the results of Examples 1, 2, 3, 6, 7 and Comparative Examples 1 and 2, by intentionally producing a pattern structure in which the portions that emit electrons and the portions that do not emit electrons are alternately arranged inside the device, It was found that electrons were emitted uniformly and with good controllability.
Moreover, from the results of Examples 2 to 5, it was found that the thickness of the electron acceleration layer is preferably 0.3 μm or more and 2 μm or less. Furthermore, from the results of Examples 1, 6, and 7, it was found that the small holes are preferably 15 μm square or more and 100 μm square or less.

  The electron-emitting device according to the present invention can obtain a sufficient amount of electron emission by applying an appropriate voltage and can operate continuously for a long time. Therefore, for example, a charging device of an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile, an image display device combined with an electron beam curing device or a light emitter, or an ion wind generated by emitted electrons. It can apply suitably to the ion wind generator etc. by utilizing this.

1 First electrode (electrode substrate)
2 Electron emission control insulating film 2a Small hole 3, 23 Electron acceleration layer 3a Insulating fine particles 4 Carbon thin film 5 Second electrode (thin film electrode)
7 Power supply unit 9, 29 Electron emission element 10, 10x, 10y, 210 Electron emission device element 31, 131, 231 Self-luminous device 32, 132 Phosphor layer 33 ITO film 34 Glass substrate 35 Second power source unit 36 Light emitting unit 42 Blower Fan 90 Charging device 340 Image display device 150, 160 Ion wind generator 330 Liquid crystal panel P Photoconductor Q Cooled body

Claims (21)

A first electrode;
Formed on the first electrode, and the electron emission control insulating film having a plurality of small holes penetrating in the thickness direction,
An electron acceleration layer containing at least insulating fine particles formed on the electron emission control insulating film;
A second electrode formed on the electron acceleration layer,
The small hole has an inner diameter of 21.2 to 141.4 μm,
In the electron emission control insulating film, the plurality of small holes are uniformly arranged at a density of 5 to 2000 holes / mm ² ,
The first electrode and the second electrode overlap the plurality of small holes,
By applying a voltage between the first electrode and the second electrode, electrons emitted from the first electrode are accelerated at the positions of the plurality of small holes arranged uniformly in the electron emission control insulating film. An electron-emitting device configured to be accelerated by a layer and emitted from the second electrode to the outside.   2. The electron-emitting device according to claim 1, wherein the electron acceleration layer has a layer thickness of 0.3 to 2.0 μm, and the small holes have an inner diameter of 8.5 to 300 times the layer thickness of the electron acceleration layer. . The small holes, polygonal, circular, electron-emitting device according to claim 1 or 2 having one of the planar shape of the elliptical shape. The electron emission control insulating film, a silicon oxide film, a silicon nitride film, a silicone resin film, the electron emitting device according to any one of claims 1 to 3 made of an acrylic resin film or a polyimide resin film. An electron-emitting device according to any one of claims 1-4, wherein the insulating particles have an average particle size of 5 to 1000 nm. The insulating fine particles, SiO _2, Al ₂ O ₃ and the electron-emitting device according to any one of claims 1 to 5 comprising particles formed from at least one of TiO _2. The second electrode, gold, silver, tungsten, titanium, an electron emitting device according to any one of claims 1 to 6 comprising at least one of aluminum and palladium. Wherein the surface of the second electrode side of the electron acceleration layer, an electron-emitting device according to any one of claims 1 to 7 carbon thin film is formed. The electron-emitting device according to any one of claims 1 to 8 , wherein the plurality of small holes are arranged in a matrix. An electron-emitting device comprising: the electron-emitting device according to any one of claims 1 to 9 ; and a power supply unit that applies a voltage between the first electrode and the second electrode. A self-luminous device comprising the electron-emitting device according to claim 10 and a light emitter, wherein the light-emitting device is excited by the electrons emitted from the electron emitter to emit light. An image display device comprising the self-luminous device according to claim 11 . An ion wind generator comprising the electron emission device according to claim 10 and configured to generate an ion wind by emitting electrons from the electron emission device toward a cooled object. The ion wind generator according to claim 13 , further comprising a blower fan that generates an air flow toward the object to be cooled. A charging device comprising the electron emission device according to claim 10 , wherein the photoconductor is charged by emitting electrons from the electron emission device toward the photoconductor. An image forming apparatus comprising the charging device according to claim 15 . Forming an electron emission control insulating film having a plurality of small holes penetrating in the film thickness direction on the first electrode (A);
(B) forming an electron acceleration layer containing at least insulating fine particles on the first electrode in the plurality of small holes of the electron emission control insulating film; and forming a second electrode on the electron acceleration layer. look including a step (C) to be,
The second electrode is formed to overlap the first electrode and the plurality of small holes,
The small hole has an inner diameter of 21.2 to 141.4 μm,
In the electron emission control insulating film, the plurality of small holes are uniformly arranged at a density of 5 to 2000 holes / mm ² . The step (A) includes a step (A1) of forming an insulating film on the first electrode, a step (A2) of forming a resist pattern film on the insulating film, and the insulating film using the resist pattern film as a mask. The method of manufacturing an electron-emitting device according to claim 17 , further comprising: (A3) forming the plurality of small holes by etching and forming the electron emission control insulating film thereby. Wherein A electron acceleration layer first electrode-side surface and at least one of a surface of the second electrode side of said at positions ostium facing, or claim 17 further comprising the step of forming the thin carbon film 18 A method for manufacturing the electron-emitting device according to the above. The step (B) includes a step (B1) of preparing a fine particle dispersion in which the insulating fine particles are dispersed in a solvent, a step (B2) of applying the fine particle dispersion on the electron emission control insulating film, The method of manufacturing an electron-emitting device according to any one of claims 17 to 19 , further comprising a step (B3) of drying the coating film of the fine particle dispersion. 21. The method of manufacturing an electron-emitting device according to claim 20 , wherein the step (B2) is a step of applying the fine particle dispersion by a spin coating method.