JP2013037784A - Electron emission element and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron emission element that can be usable when enlarged, and a manufacturing method thereof.SOLUTION: An electron emission element 1 includes an electrode substrate 2, a particulate layer 3, a thin film electrode 4 and an electric insulation layer 5. The electrode substrate 2 is a structure having conductivity to support the particulate layer 3, the thin film electrode 4, and the electric insulation layer 5. The electric insulation layer 5 is formed on the electrode substrate 2, and has plural opening parts 6. Openings 6A formed by the opening parts 6 are filled with the particulate layer 3 between the electrode substrate 2 and the thin film electrode 4. The particulate layer 3 is constituted by a first particulate layer 31 including an insulative particulate and a conductive particulate, and a second particulate layer 32 including an insulative particulate. The thin film electrode 4 is formed along surface shapes of the particulate layer 3 and the electric insulation layer 5.

Description

  The present invention relates to an electron-emitting device that emits electrons and a method for manufacturing the same.

  Known electron-emitting devices according to the prior art include a Spindt-type electrode and a carbon nanotube (abbreviated as “CNT”)-type electrode. The electron-emitting device is expected to be applied to, for example, the field emission display (FED) field. In such an electron-emitting device, a voltage is applied to a sharp shape portion to form a strong electric field of about 1 GV / m, and electrons are emitted by a tunnel effect.

  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. There is a problem in that positive ions generated by ionization of gas molecules are accelerated and collided toward the surface of the electron-emitting device by a strong electric field, and the electron-emitting device is destroyed by sputtering.

  In addition, oxygen in the atmosphere generates ozone prior to the generation of ions because dissociation energy is lower than ionization energy. Since ozone is harmful to the human body and oxidizes various things with a strong oxidizing power, there is a problem of damaging members around the electron-emitting device. In order to cope with such a problem, it is necessary to use an expensive ozone-resistant material for the peripheral member.

  For the above-mentioned problems, MIM (Metal Insulator Metal) type and MIS (Metal Insulator Semiconductor) type electron emitting devices are known as conventional technologies for preventing the destruction of the electron emitting device by sputtering and suppressing the generation of ozone. ing. These electron-emitting devices are surface-emission type electron-emitting devices that accelerate electrons using the quantum size effect and strong electric field inside the electron-emitting device, and emit electrons from the surface of the planar electron-emitting device. Since electrons accelerated by the electron acceleration layer inside the electron-emitting device are emitted, a strong electric field is not required outside the electron-emitting device. Therefore, in the MIM type and MIS type electron emitting devices, the problem of being destroyed by sputtering due to ionization of gas molecules and the problem of generating a large amount of ozone, like the Spindt type and CNT type electron emitting devices, are overcome. can do.

Further, with respect to the above-mentioned problems, and enables stable electron emission in the atmosphere, the electron-emitting device capable of suppressing generation of harmful substances such as ozone and NO _X due to electron emission, for example described in Patent Document 1 An electron-emitting device has been developed. In this electron-emitting device, an electron acceleration layer including conductive fine particles having a strong anti-oxidation effect and an insulating material larger than the size of the conductive fine particles is provided between electrodes.

JP 2009-146891 A

  However, although the electron-emitting device described in Patent Document 1 enables stable electron emission even under atmospheric pressure, it has a very large problem with respect to the increase in size of the electron-emitting device. The biggest problem in increasing the size is maintaining the electrical conductivity of the thin film electrode formed on the surface of the electron-emitting device.

  In this electron-emitting device, a thin film electrode is formed by sputtering. However, a very large amount of organic substances are emitted from the fine particle layer of the electron-emitting device in the process of forming the thin-film electrode, so-called outgas problem. There is. Usually, in order to reduce the outgas emitted during film formation, the substrate is degassed. However, many organic substances that are emitted are added as necessary functions. It cannot be actively lost. That is, the organic substance is derived from a solvent for the fine particle dispersant, a substance accompanying the silicon resin for solidifying the fine particles, or a coating agent for preventing moisture adsorption to the fine particles. The thin film electrode is in a state where the sputtered metal fine particles and the emitted organic substance are mixed, that is, a metal thin film in which a large amount of contamination occurs, and thus the electrical conductivity of the original metal thin film cannot be obtained.

  The thin-film electrode formed in such a state has a large electric resistance particularly in the plane direction. Therefore, as the electrode becomes larger, that is, the electron-emitting device becomes larger, the thin-film electrode has a potential depending on how the voltage is applied. A gradient is formed. That is, the same voltage as the applied voltage is applied at the portion near the voltage supply point of the thin film electrode, but at a portion far from the voltage supply point, it is a fraction or a few tenths depending on the electric resistance of the thin film electrode. Only the voltage is applied. If such a voltage drop occurs and falls below the electric field intensity required for electron emission, a portion where electrons are not emitted is generated and cannot be used as a planar electron source.

  Further, when the applied voltage is increased, an excessive voltage is supplied to a portion where a predetermined voltage is applied, resulting in partial deterioration and destruction of the electron-emitting device. For this reason, a new device structure is desired that enables creation of a large-sized electron-emitting device in line with actual use.

  Patent Document 1 discloses an electron-emitting device structure having an insulating layer having a plurality of openings (φ50 nm through-holes) penetrating in the thickness direction of the layer and containing conductive fine particles in the openings. It is disclosed. This structure can overcome the potential gradient generated in the thin film electrode described above, but is difficult to realize due to some obstacles.

  First, in order to form an electric field necessary for electron emission in the opening, it is difficult to uniformly fill the opening with conductive fine particles. Since the conductive fine particle is a conductor, if the filling amount increases to some extent, it becomes a simple electric conduction path, and the electric resistance necessary for forming an electric field cannot be maintained. In particular, when the element area is increased, the amount of the conductive fine particles filled in only one part of the opening is excessive, and the excessive part becomes an electric conduction path. As a result, the function of the system is impaired.

  Secondly, the electron-emitting device having this structure emits electrons in the initial stage of the conductive path forming process of the electron-emitting device, that is, the so-called forming process, but the function is achieved in a very short time as the forming process progresses. It is a point that stops. From the analysis of the operation of the electron-emitting device, it has recently been clarified that the electron emission point of the device is located in a hole (hole) having a diameter of 500 nm to 5 μm formed in the thin film electrode on the surface. The hole (hole) of the thin film electrode is a region where the surface electrode has completely disappeared, is generated by the forming process, and functions as an electron emission point. Since the size of the hole (hole) is larger than the diameter of the opening, no voltage is applied to the opening existing in the hole and no electric field is generated, so that the hole does not function as an electron emission point. In order for the electron emission point to maintain its function, the region to which a voltage is applied for electron emission must be greater than or equal to the hole of the thin film electrode.

  An object of the present invention is to provide an electron-emitting device that can be enlarged to withstand actual use and a manufacturing method thereof.

The present invention includes a plate-like first electrode;
A second electrode formed opposite the first electrode;
An electrical insulating layer formed between the first electrode and the second electrode and having a plurality of openings filled with a fine particle layer containing insulating fine particles and conductive fine particles;
When a voltage is applied between the first electrode and the second electrode, electrons emitted from the first electrode pass through the fine particle layer, pass through the second electrode, and are emitted from the second electrode. It is an electron-emitting device characterized by comprising.

In the invention, it is preferable that the shape of a cross section perpendicular to the depth direction of each opening formed in the electrical insulating layer is a square having a side of 10 μm or more and 500 μm or less.
In the invention, it is preferable that the electrical insulating layer is made of an acrylic resin.

  The present invention is characterized in that the plurality of openings formed in the electrical insulating layer are arranged in a range where the first electrode and the second electrode face each other.

  In the invention, it is preferable that the second electrode has a plurality of concave portions facing outward on a surface facing outward.

  Further, according to the present invention, the second electrode has a first thin film electrode layer formed on the fine particle layer side, and a second thin film electrode having a resistance value lower than that of the first thin film electrode layer and the plurality of recesses formed. And a layer.

  In the invention, it is preferable that the second thin film electrode layer is electrically connected to the fine particle layer when the recess penetrates the first thin film electrode layer.

In the invention, it is preferable that the first thin film electrode layer is an amorphous carbon layer.
In the invention, it is preferable that the second thin film electrode layer is a metal layer.

  In the invention, it is preferable that the metal layer contains at least one of gold, silver, tungsten, titanium, aluminum, and palladium.

  According to the present invention, the fine particle layer further includes an insulating fine particle layer formed of insulating fine particles.

  The present invention is also characterized in that the insulating fine particles and conductive fine particles contained in the fine particle layer are fixed by a silicon resin.

  In the invention, it is preferable that the conductive fine particles include at least one of gold, silver, platinum, palladium, and nickel, and have an average particle diameter of 3 to 10 nm.

  Further, the present invention is characterized in that the insulating fine particles include at least one of silicon dioxide, aluminum oxide, and titanium dioxide, and the particle diameter thereof is an average diameter of 10 to 1000 nm.

The present invention also provides an electrical insulation layer forming step of forming an electrical insulation layer having a plurality of openings on the plate-like first electrode;
A fine particle layer forming step of forming a fine particle layer composed of conductive fine particles and insulating fine particles on the surface of the electric insulating layer formed in the electric insulating layer forming step;
A removal step of removing the fine particle layer formed on the surface of the electrically insulating layer excluding the opening;
The second electrode, which is a thin film electrode, is formed in a shape that conforms to the shape of the surface of the electrically insulating layer from which the fine particle layer has been removed and the shape of the surface of the fine particle layer filled in the opening formed by the opening. And a film process.

  According to the present invention, the electron-emitting device is formed between the plate-shaped first electrode, the second electrode formed to face the first electrode, and the first electrode and the second electrode, and has an insulating property. And an electrically insulating layer having a plurality of openings filled with a fine particle layer containing fine particles and conductive fine particles. In the electron-emitting device, when a voltage is applied between the first electrode and the second electrode, electrons emitted from the first electrode are transmitted through the fine particle layer and further transmitted through the second electrode. It is configured to be emitted from two electrodes.

  Therefore, the second electrode is formed in a form along the surface shape formed by the electrically insulating layer and the fine particle layer. Among these, the second electrode formed on the surface of the electrical insulating layer is hardly affected by the contamination derived from the material constituting the fine particle layer when the electrode is formed by sputtering, and maintains a good electrical conductivity. Become. This part is called an “electric supply path”. When a voltage is applied to the second electrode, the potential drop in the electric supply path is extremely small. Therefore, even if the line length of the electric supply path increases, the electron-emitting device supplies a voltage equivalent to the applied voltage value. It becomes possible. Therefore, even when the electron-emitting device is increased in size, it is possible to apply a uniform voltage with almost no potential distribution in the second electrode plane.

  Further, since the fine particle layer formed in the opening of the electric insulating layer is made of a mixture of insulating fine particles and conductive fine particles, the electric resistance of the electron-emitting device can be easily and uniformly adjusted. Therefore, the electron-emitting device has a device configuration that can realize a large area. Therefore, the electron-emitting device has a large area and can maintain uniform electron emission in the surface direction for a long period of time.

  According to the invention, the shape of the cross section perpendicular to the depth direction of each opening formed in the electrical insulating layer is a square having a side of 10 μm or more and 500 μm or less. Thus, since the size of the opening formed in the electrical insulating layer is made larger than 10 μm square, the electron-emitting device can be formed even if a hole (hole) is formed in the second electrode by the forming process of the electron-emitting device. It becomes possible to continue applying a voltage to the electron emission portion via the electrode around the hole (hole).

  According to the invention, since the electrical insulation layer is made of an acrylic resin, the electrical insulation layer has good electrical insulation performance, heat resistance, and surface hardness, and can easily form an arbitrary pattern. .

  According to the invention, the plurality of openings formed in the electrical insulating layer are disposed within a range where the first electrode and the second electrode face each other. Therefore, the electron-emitting device can make the bias of the electric field derived from the outer edge portion of the second electrode independent of the formation of the current path in the electric field formed between the first electrode and the second electrode.

  According to the invention, the second electrode has a plurality of recesses facing outward on the surface facing outward. The physical configuration of the recess serves as a trigger for functioning as an electron emission point. Therefore, the electron-emitting device can surely form the electron emission point of the device on the device surface.

  According to the invention, the second electrode has a first thin film electrode layer formed on the fine particle layer side and a second thin film having a resistance value lower than that of the first thin film electrode layer and formed with the plurality of recesses. An electrode layer. Therefore, when a voltage is applied to the second electrode, the electron-emitting device can form an electric current path by concentrating the electric field on the fine particle layer immediately below the recess. The current path functions as an electron emission unit.

  According to the invention, the second thin film electrode layer is electrically connected to the fine particle layer 3 when the recess penetrates the first thin film electrode layer. Therefore, the electron-emitting device can concentrate the electric field on the outer peripheral portion of the connection portion between the second thin film electrode layer and the fine particle layer, particularly on the fine particle layer immediately below the connection portion.

According to the invention, the first thin film electrode layer is an amorphous carbon layer. Therefore, the electron-emitting device can cause the first electrode layer to function as a resistance layer.

  According to the invention, the second thin film electrode layer is a metal layer. Due to the presence of this metal layer, the second electrode can function as an electrode.

  According to the invention, the metal layer includes at least one of gold, silver, tungsten, titanium, aluminum, and palladium. Thus, since the electron-emitting device uses a metal material having a low work function as the metal layer, the efficiency of electron emission from the surface of the electron-emitting device to the space is improved.

  According to the invention, the fine particle layer further includes an insulating fine particle layer formed of insulating fine particles. Therefore, the electron-emitting device can relieve irregularities on the surface of the fine particle layer, prevent the generation of a local strong electric field, the concentration of current generated in the portion of the strong electric field, and the accidental occurrence caused by long-time energization. Current concentration can be prevented.

  According to the invention, the insulating fine particles and the conductive fine particles contained in the fine particle layer are fixed by the silicon resin. Therefore, for example, a thermosetting silicone resin is mixed in the fine particle dispersion forming the fine particle layer. After the fine particle layer is formed, the fine particle layer is solidified and fixed by thermally curing the silicon resin. As a result, the mechanical strength of the fine particle layer is improved, and only the fine particle layer filled in the opening of the electrical insulating layer can be left at the time of peeling the fine particle layer using a scraper. Further, since the silicon resin has a water repellent function, the electron-emitting device can suppress adhesion of water molecules contained in the atmosphere to the fine particle layer. As a result, since the electron-emitting device can suppress a change in electrical resistance due to water molecule adhesion, the electron-emitting device can operate stably even in an operating atmosphere with humidity fluctuations.

  According to the invention, the conductive fine particles include at least one of gold, silver, platinum, palladium, and nickel, and have an average diameter of 3 to 10 nm. Similar to the material used for the second electrode, these materials are less susceptible to deterioration of the electron-emitting device, including oxidation by oxygen in the atmosphere. Therefore, the electron-emitting device can be continuously driven for a long time even under atmospheric pressure. In addition, since the conductive fine particles have an average diameter of 3 to 10 nm, dielectric breakdown is less likely to occur in the fine particle layer serving as an electron path, and an electron emission phenomenon is likely to occur.

  According to the invention, the insulating fine particles include at least one of silicon dioxide, aluminum oxide, and titanium dioxide, and the average particle diameter thereof is 10 to 1000 nm. Since oxides such as silicon dioxide, aluminum oxide, and titanium dioxide have high insulating properties, the electron-emitting device sets the resistance value of the fine particle layer to an arbitrary range by adjusting the mixing ratio with the conductive fine particles. be able to. In addition, since the oxide is used as the material for the insulating fine particles, the electron-emitting device is less likely to be oxidized due to oxygen in the atmosphere even when continuously driven for a long time at atmospheric pressure. Can be prevented. Therefore, the electron-emitting device can be continuously driven for a long time.

  According to the invention, in the electrical insulating layer forming step, the electrical insulating layer having a plurality of openings is formed on the plate-like first electrode. In the fine particle layer forming step, a fine particle layer composed of conductive fine particles and insulating fine particles is formed on the surface of the electric insulating layer formed in the electric insulating layer forming step. In the removing step, the fine particle layer formed on the surface of the electrical insulating layer excluding the opening is removed. In the film forming step, the second electrode, which is a thin film electrode, is aligned with the shape of the surface of the electrical insulating layer from which the fine particle layer has been removed and the shape of the surface of the fine particle layer filled in the opening formed by the opening. The film is formed in a different shape.

  Therefore, the second electrode is formed in a form along the surface shape formed by the electrically insulating layer and the fine particle layer. Among these, the second electrode formed on the surface of the electrical insulating layer is hardly affected by the contamination derived from the material constituting the fine particle layer when the electrode is formed by sputtering, and maintains a good electrical conductivity. Become. When a voltage is applied to the second electrode, the potential drop in the electric supply path is extremely small. Therefore, even if the line length of the electric supply path increases, the electron-emitting device supplies a voltage equivalent to the applied voltage value. It becomes possible. Therefore, even when the electron-emitting device is increased in size, it is possible to apply a uniform voltage with almost no potential distribution in the second electrode plane.

  Further, since the fine particle layer formed in the opening of the electric insulating layer is made of a mixture of insulating fine particles and conductive fine particles, the electric resistance of the electron-emitting device can be easily and uniformly adjusted. Therefore, the electron-emitting device has a device configuration that can realize a large area. Therefore, the electron-emitting device has a large area and can maintain uniform electron emission in the surface direction for a long period of time.

1 is a diagram showing a cross section of an electron-emitting device 1 and a configuration of an electron-emitting device 10 according to an embodiment of the present invention. It is the figure which looked at the electron-emitting device 1 from cut surface line AA. 1 is a perspective view of an electron emitter 1. 3 is a diagram showing a measurement system for measuring voltage-current characteristics of the electron-emitting device 1. FIG. FIG. 4 is a diagram illustrating voltage-current characteristics of an example of the electron-emitting device 1. It is a figure which shows the voltage-current characteristic of the electron-emitting element of a comparative example. 2 is a surface photograph of an electron-emitting device 100 of a comparative example.

  FIG. 1 is a diagram showing a cross section of an electron-emitting device 1 and a configuration of an electron-emitting device 10 according to an embodiment of the present invention. The electron-emitting device 1 includes an electrode substrate 2, a fine particle layer 3, a thin film electrode 4, and an electrical insulating layer 5. The electrical insulating layer 5 is formed on the electrode substrate 2 and has a plurality of openings 6. The fine particle layer 3 is filled in the opening 6 </ b> A formed by the opening 6 of the electrical insulating layer 5. The thin film electrode 4 is formed in a form along the surface shape of the electrical insulating layer 5 and the fine particle layer 3. The electron emission device 10 includes an electron emission element 1 and a power source 11. The power source 11 is connected to the electrode substrate 2 and the thin film electrode 4.

  When a voltage is applied between the electrode substrate 2 and the thin-film electrode 4, the electron-emitting device 1 moves when the electrons supplied from the electrode substrate 2 pass through the fine particle layer 3 and move to the thin-film electrode 4. Some energy is given to the electrons, and the electrons are emitted from the thin film electrode 4 into the space.

  The physical phenomenon leading to the electron emission has many unclear points at the present time and is not in the range of estimation, but is related to the Joule heat caused by the current flowing through the fine particle layer 3 and the strong electric field region formed in the fine particle layer 3. It is expected that

  Generally, thermal electron emission, photoelectron emission, field electron emission, secondary electron emission, and the like are known as physical mechanisms by which electrons are emitted from the inside to the outside of the solid. Thermionic emission is performed by applying energy (work function) corresponding to the energy barrier between the Fermi level (level filled with electrons at zero K) and the vacuum level by heat, so that the electron is put into vacuum. It is a phenomenon that is released.

In addition, field electron emission (cold field electron emission) is achieved by setting the electric field strength formed between the metal surface and the vacuum to about 1 × 10 ⁹ V / m and making the energy barrier very thin, even at about room temperature. This is a phenomenon in which electrons are emitted into vacuum by the tunnel effect. This phenomenon in which thermionic emission and field electron emission are mixed is called thermal field emission, and is considered to be the most appropriate mechanism as the electron emission mechanism of the electron-emitting device 1. That is, it is considered that the electron work is caused by the combination of the apparent work function decrease due to Joule heat, the energy barrier decrease due to the strong electric field, and the tunnel phenomenon.

  In addition, electrons generated inside the fine particle layer 3 are expected to be transmitted to the atmosphere through the thin film electrode 4, but in the electron-emitting device 1, the possibility is considered to be particularly low. . In the electron-emitting device 1, destruction (disappearance) of the extremely fine thin film electrode 4 during the forming process has been confirmed. The destruction (disappearance) of the extremely fine thin film electrode 4 means that an extremely fine portion of the thin film electrode 4 loses its function as an electrode. Hereinafter, an extremely fine portion that has lost its function as an electrode is referred to as a hole portion. From recent analysis, it has been confirmed that the hole portion generated on the surface of the thin film electrode 4 functions as an electron emission point, and electrons pass through the hole portion of the thin film electrode 4 and reach the atmosphere. It seems that we can conclude.

  More specifically, an extremely fine disappearance of the thin-film electrode 4 occurs due to a conductive path forming process necessary for forming an electron emission point of the electron-emitting device 1, a so-called forming process. The forming process is a means for boosting the voltage applied to the electron-emitting device 1 in a slow step in the atmosphere in the atmosphere, and the electron-emitting device according to the prior art is equivalent to the means used as a pretreatment for generating the electron-emitting device. belongs to. The electron emission portion formed in the thin film electrode 4, that is, the hole portion of the thin film electrode 4 has a diameter of about 500 nm to 5 μm. It is considered that electrons are emitted from the periphery of the hole portion of the thin film electrode 4 by applying a voltage between the edge portion of the hole portion formed in the thin film electrode 4 and the electrode substrate 2. By making the opening 6 formed in the electrical insulating layer 5 sufficiently larger than the hole portion of the thin film electrode 4, it is possible to maintain the electron emission even if the thin film electrode 4 is lost very finely.

  The electrode substrate 2 that is the first electrode may be formed of aluminum, for example. The electrode substrate 2 is arranged below the thickness direction of the electron-emitting device 1 shown in FIG. The electrode substrate 2 is a lower electrode and has a function as a substrate. The shape of the electrode substrate 2 is, for example, a plate shape. The electrode substrate 2 is a conductive structure and may be a structure that supports the fine particle layer 3, the thin film electrode 4, and the electrical insulating layer 5. For this reason, the electrode substrate 2 is a substrate having a certain degree of strength and good conductivity.

  As a substrate usable for the electrode substrate 2, in addition to aluminum, metals such as stainless steel (hereinafter referred to as “SUS”), titanium (hereinafter referred to as “Ti”), and copper (hereinafter referred to as “Cu”) are used. Examples include substrates and semiconductor substrates such as silicon (hereinafter referred to as “Si”), germanium (hereinafter referred to as “Ge”), and gallium arsenide (hereinafter referred to as “GaAs”). Alternatively, an insulator substrate in which an electrode formed of a conductive material is formed on the surface thereof may be used. Examples of such a substrate include a glass substrate and a plastic substrate having a metal film formed on the surface.

  As a conductive material used for forming such an electrode, a material capable of forming a thin film by using a magnetron sputtering method or the like is selected. If the electron-emitting device 1 is stably operated in the atmosphere, it is preferable to use a conductive material having high antioxidation power. Preferably, a noble metal is used. Indium tin oxide (hereinafter referred to as “ITO”), which is an oxide conductive material and is widely used for transparent electrodes, is also useful. In addition, a laminated film of titanium and copper or a laminated film in which an aluminum thin film is sandwiched between molybdenum thin films may be used because a tough thin film can be formed. For example, a metal thin film in which a titanium film having a thickness of 200 nm is formed on a glass plate surface and a copper film having a thickness of 1000 nm is further stacked is useful. Also useful is a metal thin film in which molybdenum is deposited to a thickness of 20 nm on the glass plate surface, aluminum is further deposited to a thickness of 10 nm, and molybdenum is again deposited to a thickness of 20 nm.

  The electrical insulating layer 5 has an opening 6. The electrical insulating layer 5 is preferably an acrylic resin from the viewpoint of electrical insulation performance, heat resistance, surface hardness, and ease of arbitrary pattern formation processing. The acrylic resin is, for example, a photosensitive acrylic resin. The base polymer of the photosensitive acrylic resin is a polymer of methacrylic acid and glycidyl methacrylate, and includes a naphthoxydiazide positive photosensitive agent as the photosensitive agent. The film thickness of the acrylic resin needs to be 2 μm or less. The value of 2 μm or less arises from the necessity of making the electrical insulating layer 5 thicker than the fine particle layer 3 in the step of removing the fine particle layer deposited on the surface of the electrical insulating layer 5 and the electron emission characteristics of the fine particle layer 3. . The film thickness of the acrylic resin can be easily realized by spin coating of a polymer solution.

  The size of the opening 6A formed by the opening 6 (hereinafter simply referred to as “the size of the opening 6”) is preferably 10 μm square to 500 μm square. The opening 6 is provided so that the hole portion described above functions as an electron emission point. The size, particularly the minimum size, of the opening 6 is important in order to make the hole portion function as an electron emission point. In the electron-emitting device according to the prior art, destruction (disappearance) of the very thin thin-film electrode 4 that has occurred during the forming process has been confirmed. From recent analysis, holes generated on the surface of the thin-film electrode 4 of the electron-emitting device 1 are confirmed. It is confirmed that the (hole) part functions as an electron emission point. Therefore, the size of the opening 6 needs to be larger than the size of the hole (hole) generated by the forming process. Otherwise, the voltage is not applied to the portion of the thin film electrode 4 at the position corresponding to the position of the opening 6 with the disappearance of the electrode.

  Since the size of the hole portion formed in the thin film electrode 4 has a diameter of about 500 nm to 5 μm with variations in size, electron emission can be achieved by making the size of the opening 6 larger than 10 μm square. The element 1 can sufficiently sustain the electron emission. Further, when the size of the opening 6 is larger than 500 μm square, the non-uniformity of electron emission points in the opening 6 becomes conspicuous, and the electron-emitting device 1 cannot be said to be a uniform electron source in the plane direction. . The non-uniformity of the electron emission points in the opening 6 means that the distribution of the plurality of electron emission points is not uniform in the opening 6.

  The electrical insulating layer 5 is pre-baked at 150 ° C. after a coating step of applying an acrylic resin by using a spin coating method, and a portion corresponding to the opening 6 of the electrical insulating layer 5 is patterned using a metal mask and ultraviolet rays. Exposed. Thereafter, a part of the acrylic resin is removed by an etching process in which etching is performed with an alkaline developer, for example, a tetramethylammonium hydroxide developer, so that the opening 6 is formed. The acrylic resin in which the opening 6 is formed is washed with pure water, and finally the resin layer is heated and cured at 200 ° C.

  FIG. 2 is a view of the electron-emitting device 1 as viewed from the section line AA. FIG. 2 is a cross-sectional view showing the configuration of the fine particle layer 3 formed in the opening 6 and the thin film electrode 4 formed on the fine particle layer 3.

  The thin film electrode 4 as the second electrode is formed of a plurality of conductive films so that uniform and sufficient electrons are emitted from the entire thin film electrode 4. As shown in FIG. 1, the thin film electrode 4 is formed along the surface shapes of the fine particle layer 3 and the electrical insulating layer 5. The thin film electrode 4 includes an amorphous carbon layer 8, a porous electrode layer 9A, and a solid electrode layer 9B. The amorphous carbon layer 8, the porous electrode layer 9A, and the solid electrode layer 9B are arranged in this order from the fine particle layer 3 side. The thin film electrode 4 has a plurality of holes 41 formed on the surface facing outward. The hole part 41 is a concave part facing outward and forms a hole 41A. Here, the concave portion refers to a portion where the amorphous carbon layer 8 and the porous electrode layer 9A partially thin the layer film, and are arranged uniformly and discretely on the thin film electrode 4.

The amorphous carbon layer 8 that is the first thin film electrode layer is formed by randomly depositing clusters of graphite structures having S (Sharp) P (Principal) ² hybrid orbitals. A cluster is a mass of several hundred atoms. Graphite itself is a material excellent in electrical conductivity, but functions as a resistance layer because it is a deposited state in which electrical conductivity between clusters is not good. That is, the amorphous carbon layer 8 has a higher electrical resistance than the porous electrode layer 9A and the solid electrode layer 9B. Therefore, the electric resistance in the film thickness direction of the thin film electrode 4 is different between the concave portion and the portion other than the concave portion. Since the portion of the recess has a lower electric resistance than the portion other than the recess, it is easy to form a current path in the fine particle layer 3 below the recess. As a result, the electron-emitting device 1 can improve the current path formation accuracy, and can reliably increase the probability of electron emission.

  The amorphous carbon layer 8 is formed with a thickness of about 10 nm. In order for the amorphous carbon layer 8 to function as a resistance layer, it is necessary to form it with a film thickness of 5 nm or more. A plurality of holes for forming a plurality of hole portions 41 are formed in the amorphous carbon layer 8.

  9 A of porous electrode layers are formed with the material which has a metal, for example, gold | metal | money and palladium, as a main component. The material of the porous electrode layer 9A may be any material that can apply a voltage. However, from the viewpoint of the function of the electrode that allows electrons generated in the fine particle layer 3 to pass through and emit with as little energy loss as possible, a material having a low work function and capable of forming a thin film has a larger number. Electron emission can be expected. Examples of such a material include gold, silver, tungsten, titanium, aluminum, and palladium whose work function corresponds to 4 to 5 eV. In particular, when the operation of the electron-emitting device 1 under atmospheric pressure is assumed, gold having no 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. In the porous electrode layer 9 </ b> A, a plurality of holes for forming the hole portions 41 are formed at the same positions as the holes formed in the amorphous carbon layer 8.

  The solid electrode layer 9B is formed of a metal layer made of a material mainly composed of gold and palladium, similarly to the porous electrode layer 9A. Similarly to the material of the porous electrode layer 9A, the material of the solid electrode layer 9B may be any material that can apply a voltage. Therefore, the solid electrode layer 9B may be formed of the same material as the porous electrode layer 9A.

  The solid electrode layer 9B is configured to cover the porous electrode layer 9A. That is, the solid electrode layer 9B is formed so as to cover the surface of the porous electrode layer 9A. A plurality of holes 41 are formed in the solid electrode layer 9B. In order for the thin film electrode 4 to function as an electrode, a metal layer composed of the porous electrode layer 9A and the solid electrode layer 9B needs to function as an electrode. For this reason, the total thickness of the thickness of the metal layer including the porous electrode layer 9A and the solid electrode layer 9B, that is, the total thickness of the porous electrode layer 9A and the solid electrode layer 9B is 10 nm or more. Good. When the thickness of the metal layer is 10 nm or more, sufficient conductivity as an electrode can be ensured. In this embodiment, the solid electrode layer 9B is formed with a thickness of 20 nm. The porous electrode layer 9A and the solid electrode layer 9B are second thin film electrode layers.

  The film thickness of the thin film electrode 4 is important as a condition for efficiently emitting electrons from the electron-emitting device 1 to the outside, and the maximum film thickness is preferably in the range of 15 to 100 nm. Thus, the thin film electrode 4 needs to be formed with a film thickness of 100 nm or less, and the electron emission is extremely reduced in the thin film electrode 4 with a film thickness exceeding 100 nm. The decrease in the emitted electrons is considered to be because the thin film electrode 4 absorbs or reflects the electrons so that the electrons are captured again in the fine particle layer 3. Since the thin film electrode 4 only needs to function as an electrode, the thin film electrode 4 may be formed of a plurality of conductive films, that is, a conductive film having a so-called laminated structure, such as a metal film made of gold and palladium. .

  The thin film electrode 4 is formed in a form along the surface shape constituted by the electrical insulating layer 5 and the fine particle layer 3. The thin film electrode 4 formed on the surface of the electrical insulating layer 5 functions as an “electric supply path”, and the thin film electrode 4 formed on the surface of the fine particle layer 3 functions as an “electron emission surface electrode”. In particular, the thin-film electrode 4 formed on the surface of the electrical insulating layer 5 is not easily affected by contamination derived from the material constituting the fine particle layer 3 when forming an electrode by sputtering, and maintains an excellent electrical conductivity. Functions as a supply channel. Therefore, even if the electron-emitting device 1 is increased in size, the thin film electrode 4 formed on the surface of the electrical insulating layer 5, so-called “electric supply path”, does not cause a potential drop in the plane direction along the electrical conduction line, It is possible to apply a uniform voltage without potential distribution within the surface of the thin film electrode 4. Therefore, even when the electron-emitting device 1 having a large area is manufactured, it is possible to provide a surface electron emission source that can maintain the electron emission for a long period of time without any bias in the electron emission point.

  The fine particle layer 3 is filled in the opening 6 </ b> A formed by the opening 6 of the electrical insulating layer 5 and between the electrode substrate 2 and the thin film electrode 4. The fine particle layer 3 is substantially composed of insulating fine particles 7A. Specifically, as illustrated in FIG. 2, the fine particle layer 3 filled in the opening 6 </ b> A formed by the opening 6 of the electrical insulating layer 5 includes the first fine particle layer 31 formed on the electrode substrate 2. And the second fine particle layer 32 formed on the first fine particle layer 31.

  The first fine particle layer 31 includes insulating fine particles 7A and conductive fine particles 7B. The insulating fine particles 7A and the conductive fine particles 7B are mainly composed of nano-sized particles. The second fine particle layer 32 is an insulating fine particle layer.

The insulating fine particles 7A are made of silicon dioxide (abbreviated as “silica”: hereinafter referred to as “SiO ₂ ”). That is, the insulating fine particles 7A are formed of silica fine particles. The material of the insulating fine particles 7A may be any material having insulating properties, and is selected from SiO ₂ , aluminum oxide (hereinafter referred to as “Al ₂ O ₃ ”), and titanium dioxide (hereinafter referred to as “TiO ₂ ”). The material may be a main component. More specifically, for example, Cabot's Famed Silica C413 can be used. If the material is highly insulating such as SiO ₂ , Al ₂ O ₃ , and TiO ₂ , the resistance value of the fine particle layer 3 can be easily adjusted to a desired value. In addition, when these oxides are used, oxidation hardly occurs and deterioration of the electron-emitting device 1 can be prevented.

  The insulating fine particles 7A are fine particles having an average particle diameter of 50 nm. The insulating fine particles 7A preferably have an average particle size of 10 to 1000 nm, and more preferably have an average particle size of 10 to 200 nm. The insulating fine particles 7A may have a dispersion state of the particle diameter that is broad with respect to the average particle diameter. For example, fine particles having an average particle diameter of 50 nm may be widely distributed in the range of 20 to 100 nm. no problem. Therefore, even in such a dispersed state, the particle diameter of the insulating fine particles 7A only needs to satisfy the above-described range of the average particle diameter.

  When the average particle size is smaller than 10 nm, the force acting between the particles is strong, so that the particles are likely to aggregate and dispersion becomes difficult. If the average particle size is larger than 1000 nm, the dispersibility is good, but the voids of the fine particle layer 3 of the thin film become large, making it difficult to adjust the resistance of the fine particle layer 3. For this reason, it is preferable that an average particle diameter is the average particle diameter mentioned above.

  Further, the unevenness of the surface of the fine particle layer 3 causes nonuniformity of the electric field strength formed in the fine particle layer 3. In particular, since the concave portion on the surface of the fine particle layer 3 forms a portion of a local strong electric field, the conductive path tends to concentrate. When this state is remarkable, the electron emission points are concentrated in the concave portion, and the electron emission cannot be maintained in a planar shape. A condition of 200 nm is provided as a particle size for alleviating this phenomenon.

  The conductive fine particles 7B are made of silver. The conductive fine particles 7B are preferably formed using a noble metal in order to prevent the electron-emitting device 1 from being oxidized and deteriorated in the atmosphere. For example, the conductive fine particles 7B may be formed of a metal material mainly containing gold, platinum, palladium, or nickel in addition to silver. The conductive fine particles 7B can be prepared using a known fine particle production technique such as sputtering or spray heating, and commercially available metal fine particle powders such as silver nanoparticles produced and sold by Applied Nano Laboratory can also be used. is there.

  The conductive fine particles 7B are nanoparticles having an average particle diameter of 10 nm. For the conductive fine particles 7B, in order to control the conductivity of the first fine particle layer 31, it is necessary to use fine particles having an average particle size smaller than the average particle size of the insulating fine particles 7A. For this reason, it is preferable that the average particle diameter of the conductive fine particles 7B is 3 to 20 nm. By making the average particle size of the conductive fine particles 7B smaller than the average particle size of the insulating fine particles 7A, a conductive path by the conductive fine particles 7B is not formed in the fine particle layer 3, and insulation in the fine particle layer 3 is performed. Destruction is less likely to occur. When the average particle size is 3 nm or less, the cohesive force is too strong, so that the particle size cannot be maintained. The upper limit of the average particle diameter is 20 nm, which is a limitation from the manufacturing process of the electron-emitting device 1. However, when the particle diameter is too large, the film is formed due to a mass difference from the silica fine particles as the insulating fine particles 7A. It sometimes settles and cannot maintain a dispersed state. Although there are many unclear points in principle, electron emission is efficiently generated by using the conductive fine particles 7B having an average particle diameter in the range of 3 to 20 nm.

  In the first fine particle layer 31, the insulating fine particles 7A and the conductive fine particles 7B are fixed with silicon resin. Therefore, the electron-emitting device 1 having sufficient mechanical strength and capable of withstanding the processing step is formed even in the step of forming the hole for forming the hole 41 in the amorphous carbon layer 8 and the porous electrode layer 9A. The In addition, since the silicon resin has a water repellent function, water molecules are unlikely to adhere to the fine particle layer 3, and even if the electron-emitting device 1 is operated in the air, changes in electrical resistance due to the water molecules are unlikely to occur. Therefore, the electron-emitting device 1 that operates stably can be formed. For this silicon resin, for example, a room temperature / humidity curing type SR2411 silicon resin manufactured by Toray Dow Corning Silicon Co., Ltd. is used.

  The second fine particle layer 32 is composed of insulating fine particles 7A. As the insulating fine particles 7A, the same fine particles as the insulating fine particles 7A used in the first fine particle layer 31 are used. As described above, the insulating fine particles 7 </ b> A used in the second fine particle layer 32 may be the same fine particles as those in the first fine particle layer 31. In the second fine particle layer 32, the insulating fine particles 7A and the insulating fine particles 7A are fixed with silicon resin. This silicon resin is also the same as the first fine particle layer 31. Therefore, the second fine particle layer 32 also has the same effects as those described above with respect to mechanical strength and water molecule adhesion.

  The fine particle layer 3 is formed with a layer thickness of 1200 nm. The first fine particle layer 31 is formed at 700 to 800 nm, and the second fine particle layer 32 is formed at 400 to 500 nm. The fine particle layer 3 may have a layer thickness of 300 to 2000 nm in order to make the layer thickness uniform and to have uniform resistance in the layer thickness direction. The fine particle layer 3 may be formed with a combined thickness of the first fine particle layer 31 and the second fine particle layer 32 from the function as a layer for emitting electrons. When the layer thickness of the fine particle layer 3 is less than 300 nm, when forming a thin film electrode by sputtering, the metal particles of the electrode material penetrate through the gap between the fine particles to the lower surface electrode, and the upper and lower electrodes are short-circuited. In addition, the reason why the layer thickness of the fine particle layer 3 must be made thinner than 2000 nm is a limitation from the manufacturing process of the electron-emitting device 1.

  The fine particle layer 3 may be composed of only the first fine particle layer 31, but the fine particle layer 3 may be composed of the first fine particle layer 31 and the second fine particle layer 32 as in the present embodiment. That is, if the surface of the fine particle layer 3 is too large compared to the thickness of the fine particle layer 3, a local strong electric field derived from the surface shape is generated, and current concentration occurs in the strong electric field portion. Further, even when the electron-emitting device 1 is energized for a long time, an accidental current concentration point is generated in the fine particle layer 3. In order to avoid these problems, the fine particle layer 3 may be composed of the first fine particle layer 31 and the second fine particle layer 32, and the unevenness of the surface of the fine particle layer 3 may be reduced. In general, the layer thickness of the fine particle layer 3 is preferably thinner, but a slight increase in the thickness is useful for the countermeasure against the above problem.

  As described above, the fine particle layer 3 is filled in the opening 6 </ b> A formed by the opening 6 of the electrical insulating layer 5 formed on the electrode substrate 2 between the electrode substrate 2 and the thin film electrode 4. That is, the fine particle layer 3 is disposed between the electrode substrate 2 and the thin film electrode 4 in the opening 6 </ b> A formed by the opening 6 of the electrical insulating layer 5.

  FIG. 3 is a perspective view of the electron-emitting device 1. FIG. 3 schematically shows the overall shape of the electrical insulating layer 5 of the electron-emitting device 1. The positional relationship among the opening 6 formed in the electrical insulating layer 5, the fine particle layer 3 filled in the opening 6A formed by the opening 6, and the thin film electrode 4 is shown. FIG. 3 shows a state in which the electrical insulating layer 5 and the thin film electrode 4 are separated from each other on the surface of the electrical insulating layer 5 in order to show the shape and position of the opening 6 </ b> A formed by the opening 6. A broken line 51 shown on the surface of the electrical insulating layer 5 in FIG. 3 is a projection line when the outer edge portion of the thin film electrode 4 is projected onto the electrical insulating layer 5.

  The electrical insulating layer 5 has a large number of minute openings 6 arranged discretely. The opening 6 of the electrical insulating layer 5 is installed on the surface of the electrical insulating layer 5 so as to be positioned on the inner surface within the range defined by the broken line 51.

  By arranging in this way, in the electric field formed between the electrode substrate 2 and the thin film electrode 4, the bias of the electric field derived from the outer edge portion of the thin film electrode 4 becomes irrelevant to the formation of the current path. Generally, electric lines of force are concentrated at the electrode end portion as compared with the electrode surface. Therefore, when a voltage is applied between the electrode substrate 2 and the thin film electrode 4, the electrode end portion is easier to form a current path than in the electrode plane. That is, electron emission from the electron-emitting device 1 is concentrated from the outer edge of the thin film electrode 4. In order to suppress this phenomenon, it is necessary to prevent the outer edge portion of the thin film electrode 4 from flowing electricity.

  The electron-emitting device 1 includes an electrode pad 12 that forms a wiring pattern from the thin film electrode 4 to the outside of the thin film electrode 4. The electrode pad 12 is an electrical wiring in which a part of the electrode pad 12 extends to the outside of the thin film electrode 4 from a position that overlaps the thin film electrode 4 and does not overlap the opening 6 of the electrical insulating layer 5. The electrode pad 12 is a thick and strong metal layer having a layer thickness of 200 nm to 500 nm. The electrode pad 12 can apply a voltage to the electron-emitting device 1 without using a special needle probe or the like by connecting a power source 11 as an external power source to the end of the electrode pad 12. The electron-emitting device 1 is used with an electrode substrate 2 and a thin film electrode 4 connected to a power source 11.

  Next, a method for manufacturing the electron-emitting device 1 will be described. The electrode substrate 2 is formed by forming a molybdenum film of 20 nm on the surface of a 0.7 mm thick glass substrate by sputtering, forming an aluminum film of 10 nm again, and forming a molybdenum film of 20 nm again.

  In the electrical insulating layer forming step, the electrical insulating layer 5 having the opening 6 on the surface of the electrode substrate 2 is formed. In the electrical insulating layer forming step, a solution containing a photosensitive acrylic resin material is spin-coated on the electrode substrate 2, and pre-baking, pattern exposure, alkali development, and pure water cleaning are performed in this order.

  Here, the electrical insulating layer 5 is formed so that a solution containing a photosensitive acrylic resin is formed on the electrode substrate 2 by a spin coat coating method and has a thickness of 2 μm after curing. The base polymer of the photosensitive acrylic resin is a polymer of methacrylic acid and glycidyl methacrylate. In this polymer, the photosensitive portion is dissolved in the developer, and is applied to the surface of the cleaned electrode substrate 2 by a spin coating method. Subsequently, the electrode substrate 2 to which the polymer is applied is pre-baked, and a solvent of a photosensitive acrylic resin, for example, a solvent such as ethyl lactate is dried and thermally cured.

  A metal mask pattern for forming the opening 6 is overlaid and exposed on the electrode substrate 2 to which the acrylic resin is applied. The opening 6A formed by the opening 6 is a 60 μm square. In the metal mask pattern, a total of 18225 opening patterns of 135 × 135 vertical and horizontal are formed in an area of 32.2 mm × 32.2 mm.

  The acrylic resin exposed with the metal mask pattern superimposed is developed with an alkaline solution after exposure. The exposed portion of the acrylic resin is etched by the alkaline solution, and the opening 6 having a desired shape is obtained.

  Further, the acrylic resin in which the opening 6 is formed is heated by a pure water, and then heated and cured by a crosslinking reaction. The electrical insulating layer 5 and the electrode substrate 2 which are acrylic resins in which the openings 6 are formed are placed in a hot plate or an oven and heated.

  In the next fine particle layer forming step, the fine particle layer 3 is filled into the opening 6 </ b> A formed by the opening 6 of the electrical insulating layer 5. First, a dispersion A that becomes the material of the first fine particle layer 31 and a dispersion B that becomes the second fine particle layer 32 are prepared. Dispersion A is obtained by introducing insulating fine particles 7A and conductive fine particles 7B into a solvent in this order and dispersing them with an ultrasonic disperser. Dispersion B is obtained by introducing insulating fine particles 7A and a silicon resin solution in this order into a solvent and applying an ultrasonic disperser. Here, the dispersion solvent is not particularly limited as long as it can form a slurry in which each material is dispersed. For example, toluene, benzene, xylene, hexane, or the like can be used as the dispersion solvent. The dispersion method is not limited to the ultrasonic disperser, but may be dispersed by other methods.

  Next, the dispersion liquid A is applied on the electrode substrate 2 on which the electrical insulating layer 5 having the opening 6 is formed, and is applied by, for example, a spin coating method to form the first fine particle layer 31. After applying the dispersion A, the electrode substrate 2 on which the electrical insulating layer 5 is formed is heated at 150 ° C. to evaporate the solvent. In addition to the spin coating method, the dispersion A can be applied by a method such as a dropping method, a spray coating method, a spraying method, or an ink jet method. The first fine particle layer 31 having a desired film thickness can be formed by repeating the spin coating method and the application and drying by these methods.

  Subsequently, the second fine particle layer 32 is formed on the electrode substrate 2 on which the first fine particle layer 31 is formed in the same manner as in the case of the dispersion A. At this time, the silicon resin component contained in the dispersion liquid B also penetrates into the first fine particle layer 31, and as a result, the respective fine particles constituting the first fine particle layer 31 are bound by silicon resin, that is, fixed. Become. Even after the dispersion B is applied, heat treatment is performed again at 150 ° C.

  The layer thickness of the fine particle layer 3, that is, the layer thickness in which the first fine particle layer 31 and the second fine particle layer 32 are laminated is formed to be thinner than the layer thickness of the electrical insulating layer 5. This is the next removal step, so that when the scraper removes the fine particle layer formed on the surface of the electrical insulating layer 5, it does not scrape the entire fine particle layer formed on the opening 6A. is there. By making the layer thickness of the fine particle layer 3 thinner than the layer thickness of the electrical insulating layer 5, the scraper can slide only the surface of the electrical insulating layer 5.

  In the next removal step, the fine particle layer formed in the opening 6A formed by the opening 6 of the electric insulating layer 5 is left as it is, and only the fine particle layer formed on the surface of the electric insulating layer 5 is used with a scraper. And remove. In order not to damage the electric insulating layer 5, the scraper blade needs to be made of a material having a lower hardness than the cured acrylic resin. Here, the surface of the electrical insulating layer 5 is scraped off using a polypropylene blade, and the fine particle layer formed in the opening 6A formed by the opening 6 of the electrical insulating layer 5 is left as it is. Only the fine particle layer formed on the surface is removed. The dust of fine particles generated during scraping is cleaned by blowing away with an air gun. By doing so, as shown in FIG. 1, the fine particle layer 3 is filled only in the opening 6 </ b> A formed by the opening 6 of the electrical insulating layer 5.

  Next, in the film forming step, the thin film electrode 4 is formed on the electrical insulating layer 5 and the fine particle layer 3. The thin film electrode 4 includes an amorphous carbon layer 8, a porous electrode layer 9A, and a solid electrode layer 9B.

  First, in order to form the hole 41, a spherical shield functioning as a shield is dispersed in a solvent to prepare a dispersion C, and the dispersion C is formed on the electrode substrate 2 and the fine particles. Apply to the surface of layer 3. As the solvent evaporates, the spherical shield is uniformly dispersed on the surfaces of the electrical insulating layer 5 and the fine particle layer 3. The spherical shield is spherical silica particles having an average particle diameter of 8 μm.

  Next, a mask in which a region corresponding to the shape of the thin film electrode 4 is opened, that is, a mask in which a range of a broken line 51 is opened is overlaid on the surfaces of the electrical insulating layer 5 and the fine particle layer 3 on which the spherical shields are dispersed, and sputtering is performed. Then, the amorphous carbon layer 8 and the porous electrode layer 9A are continuously formed. Here, the shape of the thin film electrode 4 is a square of 35 mm × 35 mm, and gold, silver, tungsten, titanium, aluminum, palladium, or the like is used as a sputtering target. The range of the broken line 51 is a 35 mm × 35 mm square.

  Next, dry air is blown against the surface of the porous electrode layer 9A thus formed to remove the spherical shield. As a result, the amorphous carbon layer 8 and the porous electrode layer 9A in which holes for forming the holes 41 are formed are completed.

  Subsequently, the previously used mask having an opening of a 35 mm × 35 mm square area is overlaid again at the same position as the position where the amorphous carbon layer 8 and the porous electrode layer 9A are laminated, and the electrode surface on which the porous electrode layer 9A is formed. Further, a thin film of a metal material is formed by sputtering, and the mask is removed after the film formation. Thereby, the solid electrode layer 9B is formed, and the thin film electrode 4 that forms the surface of the electron-emitting device 1 is obtained.

  Finally, an electrode pad 12 serving as a wiring pattern from the thin film electrode 4 to the outside of the thin film electrode 4 is formed. The electrode pad 12 may be formed by using not only a sputtering method but also a vapor deposition method after overlapping a metal mask on which a wiring pattern is formed. Through the above steps, the electron-emitting device 1 according to this embodiment is completed.

  Hereinafter, examples of the electron-emitting device 1 used for evaluating the voltage-current characteristics will be described. The electrode substrate 2 was formed by depositing molybdenum with a thickness of 20 nm on the surface of a glass substrate having a thickness of 0.7 mm and a length and width of 41 mm × 45 mm by sputtering. Is.

  First, in the electrical insulating layer forming step, the electrical insulating layer 5 and the opening 6 are formed. A solution containing a photosensitive acrylic resin is applied to the surface of the electrode substrate 2 by spin coating, and is formed to a thickness of 2 μm after curing. The base polymer of the photosensitive acrylic resin is a polymer of methacrylic acid and glycidyl methacrylate, and the photosensitive portion is dissolved in the developer. Specifically, an acrylic resin having a viscosity of 27 cp is prepared, and the prepared acrylic resin is applied to the surface of the cleaned electrode substrate 2 at a spin rotation speed of 1000 rpm. Subsequently, the electrode substrate 2 coated with the acrylic resin is heated to 100 ° C., and a solvent of a photosensitive acrylic resin, for example, a solvent such as ethyl lactate is dried and thermally cured.

  Next, the metal substrate pattern for forming the opening 6 is overlapped and exposed on the electrode substrate 2 coated with the acrylic resin. The opening 6A formed by the opening 6 is a 60 μm square. In the metal mask pattern, a total of 18225 opening patterns of 135 × 135 vertical and horizontal are formed in an area of 32.2 mm × 32.2 mm.

  After the exposure, the acrylic resin exposed with the metal mask pattern superimposed thereon is developed with an alkaline solution, here, a solution of tetramethylammonium hydroxide. The exposed portion of the acrylic resin is etched by the alkaline solution, and the opening 6 having a desired shape is obtained.

  Further, the acrylic resin in which the opening 6 is formed is heated with a developer remaining on the surface with pure water, and then cured by a crosslinking reaction. The electrical insulating layer 5 and the electrode substrate 2 which are acrylic resins in which the openings 6 are formed are placed in an oven and heated at 200 ° C.

  In the next fine particle layer forming step, the fine particle layer 3 is formed. Into a 10 mL reagent bottle, 1.5 g of n-hexane solvent is added, and 0.25 g of silica particles are added as insulating fine particles 7A, and the reagent bottle is dispersed by an ultrasonic disperser. Here, the silica fine particles are Fame silica C413 having an average particle diameter of 50 nm manufactured by Cabot Corporation. The surface of the silica fine particles is treated with hexamethylsidirazan. By applying the dispersion to the disperser for 5 minutes, the silica fine particles are dispersed milky white in the n-hexane solvent.

  Subsequently, 0.06 g of silver nanoparticles are charged as the conductive fine particles 7B, and similarly dispersed by an ultrasonic dispersing device. The silver nanoparticles are manufactured by Applied Nano Laboratory and have an average particle diameter of 10 nm with an alcoholate insulating coating. Here, a dispersion in which silver nanoparticles are dispersed is referred to as dispersion A.

  Similarly, 1.5 g of n-hexane solvent is put into a 10 mL reagent bottle, 0.25 g of the silica particles of Famed Silica C413 is added as the insulating fine particles 7A, and the reagent bottle is similarly dispersed through an ultrasonic disperser. Let Next, 0.036 g of the silicone resin solution is added, and is similarly dispersed using an ultrasonic disperser. This silicone resin is a room temperature / moisture-curing SR2411 silicone resin manufactured by Toray Dow Corning. Here, a dispersion in which the silicone resin is dispersed is referred to as dispersion B.

  The dispersion A is dropped on the surface of the electrical insulating layer 5 having the opening 6 formed on the electrode substrate 2, and the first fine particle layer 31 is formed using a spin coating method. The electrode substrate 2 on which the first fine particle layer 31 is formed is heat-dried (hereinafter referred to as “preliminary firing”) for 1 minute using a hot plate at 150 ° C. Further, the second fine particle layer 32 is formed in the same manner using the dispersion B. Similarly, the electrode substrate 2 on which the second fine particle layer 32 is formed is heated and dried for 1 hour (hereinafter referred to as “main firing”) using a hot plate at 150 ° C.

  The film forming condition by the spin coating method is that the dispersion A or the dispersion B is dropped on the surface of the electrical insulating layer 5 while rotating at 500 rpm (hereinafter referred to as “RPM”), and then 3000 RPM. Rotate for 10 seconds.

  In the next removal step, the fine particle layer 3 formed in the opening 6A formed by the opening 6 is left as it is, and only the fine particle layer formed on the surface of the electrical insulating layer 5 is removed using a scraper. . In order not to damage the electric insulating layer 5, the scraper blade needs to be made of a material having a lower hardness than the cured acrylic resin. Here, the surface of the electrical insulating layer 5 is scraped off using a polypropylene blade, and the fine particle layer 3 formed in the opening 6 </ b> A formed by the opening 6 is left as it is, and the film is formed on the surface of the electrical insulating layer 5. Only the formed fine particle layer is removed. The dust of fine particles generated during scraping is cleaned by blowing away with an air gun.

  Next, in the film forming process, the thin film electrode 4 is formed. 1.0 g of ethanol solvent is put into a 10 mL reagent bottle, 0.1 g of silica particles is put as a spherical shield, and is dispersed for 5 minutes using an ultrasonic disperser. Here, the silica fine particles are fumed silica SE-5V having an average particle diameter of 8 μm manufactured by Tokuyama Corporation, and the surface of the silica fine particles is subjected to hexamethylsidirazan treatment. Here, a dispersion in which silica fine particles are dispersed is referred to as a dispersion C.

  The dispersion C is dropped on the surfaces of the electrical insulating layer 5 and the fine particle layer 3 formed on the electrode substrate 2, and the spherical shield is uniformly dispersed using a spin coating method. After spraying, the electrode substrate 2 on which the electrical insulating layer 5 and the fine particle layer 3 formed on the electrode substrate 2 are heated for 1 minute using a hot plate at 150 ° C. to evaporate the solvent.

  A region corresponding to the shape of the thin film electrode 4, specifically, a metal mask having an opening of a 35 mm × 35 mm square region where the thin film electrode 4 is disposed, the electrical insulating layer 5 and the fine particle layer in which the spherical shields are dispersed. 3, the amorphous carbon layer 8 is deposited using a resistance overheating type vapor deposition machine, and subsequently deposited using a gold palladium (hereinafter referred to as “Au—Pd”) target using a sputtering apparatus. Then, an Au—Pd electrode film that is the basis of the porous electrode layer 9A is obtained. The film thickness of the amorphous carbon layer 8 is 10 nm, and the film thickness of the Au—Pd electrode film is 20 nm.

  After removing the metal mask, the surface of the thin film electrode 4 is blown using dry air to remove the spherical shield. The Au—Pd electrode film from which the spherical shield has been removed is the porous electrode layer 9A. The portion where the amorphous carbon layer 8 and the porous electrode layer 9A are not stacked due to the presence of the spherical shield is a hole for forming the hole 41 of the thin film electrode 4.

Subsequently, the metal mask used for the formation of the amorphous carbon layer 8 and the porous electrode layer 9A was again stacked at the same position as the position where the amorphous carbon layer 8 and the porous electrode layer 9A were laminated to form the porous electrode layer 9A. A solid electrode layer 9B made of Au—Pd is formed on the entire surface by sputtering. The film thickness of the solid electrode layer 9B is 20 nm. The solid electrode layer 9B is a thin film of a metal material. After the solid electrode layer 9B is formed, the metal mask is removed. By removing the metal mask, the solid electrode layer 9B is completed, and the thin film electrode 4 that forms the surface of the electron-emitting device 1 is formed. A hole 41 is formed in a portion where the amorphous carbon layer 8 and the porous electrode layer 9A are not laminated. As a result of measurement of the shape and number of holes 41 using an electron microscope (Scanning Electron Microscope: abbreviated as “SEM”), the size of the holes 41 is 4.5 μm in diameter, and the dispersion state of the holes 41 is 930. Pieces / mm ² .

  Finally, an electrode pad 12 serving as a wiring pattern connected from the thin film electrode 4 to the outside of the thin film electrode 4 is formed. The electrode pad 12 is formed using a vacuum deposition method after a metal mask on which a wiring pattern is formed is overlaid. Since the electrode pad 12 is a simple electric wiring, it is preferable that the electrode pad 12 be formed thick. In this embodiment, the electrode pad 12 has a thickness of 200 nm.

  FIG. 4 is a diagram illustrating a measurement system that measures the voltage-current characteristics of the electron-emitting device 1. The measurement system shown in FIG. 4 is a measurement system that measures the voltage-current characteristics of the electron-emitting device 1 of the above-described embodiment.

  In the measurement system shown in FIG. 4, a mesh counter electrode 14 made of SUS (hereinafter referred to as “counter electrode”) is sandwiched between an insulator spacer 13 made of polyimide on the outside of the porous thin film electrode 4 of the electron-emitting device 1. Is arranged). The porosity process is a process for forming the hole 41. The height of the insulator spacer 13 is 5 mm. Between the electrode substrate 2 and the thin film electrode 4, a voltage composed of a rectangular wave having a voltage V <b> 1 is applied by a rectangular wave power supply 15, and a direct current voltage V <b> 2 is applied to the counter electrode 14 by a direct current power supply 16. The In this measurement system, the current flowing between the thin film electrode 4 and the rectangular wave power supply 15 is measured as the in-element current Ip, and the current flowing between the counter electrode 14 and the DC power supply 16 is measured as the electron emission current Ie. The voltage-current characteristics in the example of the electron-emitting device 1 were measured in a measurement system installed in an environment with a temperature of 24 ° C. and a relative humidity of 30%.

  As a comparative example with respect to the embodiment of the electron-emitting device 1, an electron-emitting device in which the fine particle layer formed on the surface of the electrical insulating layer 5 is not removed is created, and the voltage-current characteristics are measured with the measurement system shown in FIG. Went. The electron-emitting device of this comparative example is the same in all other steps except that there is no step of removing the fine particle layer formed on the surface of the electrical insulating layer 5.

FIG. 5 is a diagram illustrating voltage-current characteristics of the embodiment of the electron-emitting device 1. FIG. 6 is a graph showing voltage-current characteristics of the electron-emitting device of the comparative example. Graphs 61 and 71 are the electron emission current Ie, and graphs 62 and 72 are the in-device current Ip. 5 and 6, the left vertical axis is the electron emission current Ie (A / cm ² ), the right vertical axis is the in-device current Ip (A / cm 2), and the horizontal axis is the applied voltage (V _{0). -P} ).

FIG. 5 shows measurement results when the applied voltage V1 is increased stepwise until the electron emission current Ie becomes 1 (μA / cm ² ) as measurement conditions. The applied voltage V1 is a rectangular wave having an amplitude only on the positive electrode side, and has a frequency of 500 (Hz) and a duty of 50%. The value of the applied voltage H1 represents the peak value of the rectangular wave, and the unit is expressed as “V _0-p ”. The applied voltage V2 is a DC voltage, and the voltage is 500 (V). Each measured current value is an average current value when the measurement integration time is 166 (ms). Since the frequency of the applied voltage V1 is 500 (Hz), one wavelength is 2 (ms).

The voltage-current characteristics shown in FIG. 5 show that when the electron emission current Ie becomes 1 (μA / cm ² ), the applied voltage V1 = 16 (V _0-p ), and the in-element current Ip is 61 ( mA / cm ² ). At this time, the average power consumption W1 per unit area is W1 = 8 (V _{average value} ) × 61 (mA / cm ² ) = 0.49 (W). The unit “V _{average value} ” represents an average value of one cycle of the applied voltage. It shows that the unit of average voltage is volts (V), and is a unit for obtaining the average power consumption.

FIG. 6 shows the measurement results when the applied voltage V1 is raised stepwise under the same measurement conditions as the measurement results of FIG. In the voltage-current characteristics shown in FIG. 6, when the electron emission current Ie becomes 1 (μA / cm ² ), the applied voltage V1 = 61 (V _0-p ), and the in-element current Ip = 34 (mA / cm ² ). At this time, the average power consumption W1 per unit area is W1 = 30.5 (V _{average value} ) × 34 (mA / cm ² ) = 1.04 (W).

The applied voltage V1 required to obtain 1 (μA / cm ² ) of the electron emission current Ie from the electron-emitting device 1 of the embodiment is reduced to about ¼ compared with the applied voltage V1 of the electron-emitting device of the comparative example. The power consumption is about ½. As this result shows, by removing the fine particle layer formed on the surface of the electrical insulating layer 5, unnecessary power loss can be eliminated and the electron-emitting device 1 with low power consumption can be obtained.

  The ratio of the electron emission current Ie to the in-device current Ip (hereinafter referred to as “electron emission efficiency”) is 0.0016% in the electron-emitting device 1 of the example, whereas it is 0 in the electron-emitting device of the comparative example. .0029%, and the electron-emitting device 1 of the example is somewhat deteriorated. This is considered to be derived from the electron emission mechanism of the electron-emitting device 1. That is, since the electron-emitting device of the comparative example consumes a lot of electric power, the temperature of the electron-emitting device increases accordingly. As a result of measuring the temperature of the electrode substrate 2, the temperature reached 80 to 90 ° C. in the electron-emitting device of the comparative example, but changed between 30 to 40 ° C. in the electron-emitting device 1 of the example. The increase in temperature is thought to increase the electron emission efficiency because it has the effect of raising the energy level of trapped electrons to the vacuum level.

  Further, the difference in the element structure between the example and the comparative example, that is, the difference in the element structure as to whether or not the fine particle layer formed on the surface of the electrical insulating layer 5 is removed greatly affects the lifetime. The reason why a potential gradient is generated in the thin film electrode 4 when a voltage is applied is that power loss occurs on the surface of the thin film electrode 4. The power loss is caused by an increase in electrical resistance due to the metal film quality of the thin film electrode 4. The increase in electrical resistance of the thin film electrode 4 is caused by the outgas generated from the fine particle layer 3 when the thin film electrode 4 is formed being mixed into the electrode film as a contamination.

  By increasing the applied voltage, a voltage equal to or higher than the predetermined voltage can be applied to the entire surface of the thin film electrode 4. However, before the applied voltage is increased, the voltage of the thin film electrode 4 to which the predetermined voltage has been applied is increased. An excessive voltage is applied to the surface. Such a portion to which an excessive voltage is applied occurs at an electron emission point in the vicinity of the portion where the electrode pad 12 and the thin film electrode 4 overlap. Excessive voltage application tends to cause dielectric breakdown of the fine particle layer 3 and carbon deposition, and causes rapid partial deterioration of the electron-emitting device.

  FIG. 7 is a surface photograph of the electron-emitting device 100 of the comparative example. The electron-emitting device 100 is continuously driven for 100 hours, and the above-described deterioration of the electron-emitting device 100 occurs on the surface thereof. The vertical line-like shape that can be seen on the left side of FIG. On the right side of the electrode pad 12 are the thin film electrode 4 and the electrical insulating layer 5. On the surface of the electrical insulating layer 5, the fine particle layer 3 filled in the opening 6A formed by the opening 6 is shown. The region of the fine particle layer 3 filled in the opening 6A formed by the opening 6 is a 60 μm square electron emission portion, and it can be visually observed that the color is changed by continuous driving for 100 hours.

The electron-emitting device 100 in the photograph shown in FIG. 7 controls the applied voltage so that the electron-emitting current Ie is 10 (μA / cm ²⁾ compared to the electron-emitting device 100 of the comparative example in which the applied voltage is partially excessive. And after 100 hours of continuous driving. The electron emission portion adjacent to the electrode pad 12 is blackened, and carbon deposition is conspicuous. As the distance from the electrode pad 12 increases, that is, as the electrode pad 12 moves to the right in FIG. 7, the blackening of the electron emitting portion decreases, and the electron emitting device 100 maintains the initial state. Since carbon deposition inhibits electron emission from the electron-emitting device 100, it is necessary to increase the applied voltage with the progress of carbon deposition in order to maintain the electron emission current Ie. As a result, the deposition of carbon spreads over the entire electron-emitting device 100, and the blackened portion causes dielectric breakdown of the fine particle layer 3 and the electron-emitting portion is completely lost.

  Since the electron-emitting device 1 does not cause the above-described partial deterioration of the electron-emitting portion, it is not necessary to excessively increase the applied voltage. As a result, even when the area of the electron-emitting device 1 is increased, it is possible to obtain electron emission that is uniform in the surface direction and that can be driven stably for a long time in the atmosphere.

  The electron-emitting device 1 can be driven continuously over a long period of time with reduced power consumption compared to the device structure of the electron-emitting device according to the prior art. Therefore, for example, an image display device by combining with an image forming apparatus such as an electrophotographic copying machine, a printer, and a facsimile, an electron beam curing device, or a light emitter, or ions generated by emitted electrons. It can be suitably applied to a cooling device or the like using wind.

  The electron-emitting device 1 and the manufacturing method thereof are not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  As described above, the electron-emitting device 1 is formed between the plate-like electrode substrate 2, the thin film electrode 4 formed to face the electrode substrate 2, and the electrode substrate 2 and the thin film electrode 4. And an electrically insulating layer 5 in which a plurality of openings 6A filled with a fine particle layer 3 containing 7A and conductive fine particles 7B are formed. In the electron emitter 1, when a voltage is applied between the electrode substrate 2 and the thin film electrode 4, electrons emitted from the electrode substrate 2 pass through the fine particle layer 3 and further pass through the thin film electrode 4. And is configured to be emitted from the thin film electrode 4.

  Therefore, the thin film electrode 4 is formed in a form along the surface shape formed by the electrical insulating layer 5 and the fine particle layer 3. Among these, the thin film electrode 4 formed on the surface of the electrical insulating layer 5 is hardly affected by the contamination derived from the substance constituting the fine particle layer 3 when the electrode is formed by the sputtering method, and maintains a good electrical conductivity. It will be a thing. When a voltage is applied to the thin film electrode 4, the potential drop in the electric supply path is extremely small. Therefore, even if the line length of the electric supply path is increased, the electron-emitting device 1 has a voltage equivalent to the applied voltage value. Supply is possible. Therefore, even if the electron-emitting device 1 is increased in size, it is possible to apply a uniform voltage with almost no potential distribution in the surface of the thin film electrode 4.

  Further, since the fine particle layer 3 formed in the opening 6A of the electrical insulating layer 5 is composed of a mixture of the insulating fine particles 7A and the conductive fine particles 7B, the electric resistance of the electron-emitting device 1 can be easily and uniformly adjusted. It becomes possible. Therefore, the electron-emitting device 1 has a device configuration that can realize a large area. Accordingly, the electron-emitting device 1 has a large area and can maintain uniform electron emission in the surface direction for a long period of time.

  Furthermore, the shape of the cross section perpendicular to the depth direction of each opening 6A formed in the electrical insulating layer 5 is a square having a side of 10 μm or more and 500 μm or less. As described above, since the size of the opening 6A formed in the electrical insulating layer 5 is larger than 10 μm square, the electron-emitting device 1 forms a hole portion (hereinafter referred to as “hole”) in the thin film electrode 4 by the forming process. Can be applied to the electron emission portion via the electrode around the hole (hole).

  Furthermore, since the electrical insulating layer 5 is made of an acrylic resin, the electrical insulating layer 5 has good electrical insulation performance, heat resistance, and surface hardness, and can be easily formed into an arbitrary pattern.

  Further, the plurality of openings 6 </ b> A formed in the electrical insulating layer 5 are arranged in a range where the electrode substrate 2 and the thin film electrode 4 face each other. Therefore, in the electric field formed between the electrode substrate 2 and the thin film electrode 4, the electron-emitting device 1 can make the bias of the electric field derived from the outer edge of the thin film electrode 4 independent of the formation of the current path. .

  Furthermore, the thin film electrode 4 has a plurality of concave portions facing outward on the surface facing outward. The physical configuration of the recess serves as a trigger for functioning as an electron emission point. Therefore, the electron-emitting device 1 can surely form the electron emission point of the device on the device surface.

    Further, the thin film electrode 4 includes a first thin film electrode layer formed on the fine particle layer 3 side, and a second thin film electrode layer having a resistance value lower than that of the first thin film electrode layer and formed with the plurality of recesses. . Therefore, when a voltage is applied to the thin film electrode 4, the electron-emitting device 1 can concentrate an electric field on the fine particle layer 3 immediately below the recess to form a current path. The current path functions as an electron emission unit.

  Further, the second thin film electrode layer is electrically connected to the fine particle layer 3 when the recess penetrates the first thin film electrode layer. Therefore, the electron-emitting device 1 can concentrate the electric field on the outer peripheral portion of the connection portion between the second thin film electrode layer and the fine particle layer 3, particularly on the fine particle layer 3 immediately below the connection portion.

  Further, the first thin film electrode layer is an amorphous carbon layer 8. Therefore, the electron-emitting device 1 can function the first electrode layer as a resistance layer.

  Furthermore, the second thin film electrode layer is a metal layer. By having this metal layer, the thin film electrode 4 can function as an electrode.

  Furthermore, the metal layer includes at least one of gold, silver, tungsten, titanium, aluminum, and palladium. Thus, since the electron-emitting device 1 uses a metal material having a low work function as the metal layer, the electron emission efficiency from the surface of the electron-emitting device 1 to the space is improved.

  Furthermore, the fine particle layer 3 further includes a second fine particle layer 32 formed of the insulating fine particles 7A. Therefore, the electron-emitting device 1 can alleviate the unevenness of the surface of the fine particle layer 3, prevents the generation of a local strong electric field, generates a current concentration in a portion of the strong electric field, and occurs for a long time. Accidental current concentration can be prevented.

  Furthermore, the insulating fine particles 7A and the conductive fine particles 7B included in the fine particle layer 3 are fixed by silicon resin. Therefore, for example, a thermosetting silicone resin is mixed in the fine particle dispersion forming the fine particle layer 3. After the fine particle layer 3 is formed, the fine particle layer 3 is solidified and fixed by thermally curing the silicon resin. Thereby, the mechanical strength of the fine particle layer 3 is improved, and only the fine particle layer 3 filled in the opening 6A of the electrical insulating layer 5 can be left at the time of peeling the fine particle layer 3 using a scraper. Furthermore, since the silicon resin has a water repellent function, the electron-emitting device 1 can suppress adhesion of water molecules contained in the atmosphere to the fine particle layer 3. As a result, since the electron-emitting device 1 can suppress a change in electrical resistance due to water molecule adhesion, the electron-emitting device 1 can operate stably even in an operating atmosphere with humidity fluctuations.

  Furthermore, the conductive fine particles 7B include at least one of gold, silver, platinum, palladium, and nickel, and have an average diameter of 3 to 10 nm. Similar to the material used for the thin film electrode 4, these materials are less susceptible to deterioration of the electron-emitting device 1, including oxidation by oxygen in the atmosphere. Therefore, the electron-emitting device 1 can be continuously driven for a long time even under atmospheric pressure. Further, since the conductive fine particles 7B have an average particle diameter of 3 to 10 nm, dielectric breakdown does not easily occur in the fine particle layer 3 serving as an electron path, and an electron emission phenomenon is likely to occur.

  Furthermore, the insulating fine particles 7A include at least one of silicon dioxide, aluminum oxide, and titanium dioxide, and the particle diameter thereof is an average diameter of 10 to 1000 nm. Since oxides such as silicon dioxide, aluminum oxide, and titanium dioxide have high insulation, the electron-emitting device 1 can adjust the resistance value of the fine particle layer 3 to an arbitrary range by adjusting the mixing ratio with the conductive fine particles 7B. Can be set to In addition, since the oxide is used as the material of the insulating fine particles 7A, the electron-emitting device 1 is less likely to be oxidized due to oxygen in the atmosphere even when continuously driven at atmospheric pressure for a long time. Deterioration of the emitting element 1 can be suppressed. Therefore, the electron-emitting device 1 can be continuously driven for a long time.

  Furthermore, in the electrical insulating layer forming step, the electrical insulating layer 5 having a plurality of openings 6 is formed on the plate-like electrode substrate 2. In the fine particle layer forming step, a fine particle layer composed of the conductive fine particles 7B and the insulating fine particles 7A is formed on the surface of the electric insulating layer 5 formed in the electric insulating layer forming step. In the removing step, the fine particle layer formed on the surface of the electrical insulating layer 5 excluding the opening 6 is removed. In the film forming step, the thin film electrode 4 that is a thin film electrode is formed on the surface of the electric insulating layer 5 from which the fine particle layer has been removed, and the surface of the fine particle layer 3 filled in the opening 6A formed by the opening 6. The film is formed in a shape along the shape.

  Therefore, the thin film electrode 4 is formed in a form along the surface shape formed by the electrical insulating layer 5 and the fine particle layer 3. Among these, the thin film electrode 4 formed on the surface of the electrical insulating layer 5 is hardly affected by the contamination derived from the substance constituting the fine particle layer 3 when the electrode is formed by the sputtering method, and maintains a good electrical conductivity. It will be a thing. When a voltage is applied to the thin film electrode 4, the potential drop in the electric supply path is extremely small. Therefore, even if the line length of the electric supply path is increased, the electron-emitting device 1 has a voltage equivalent to the applied voltage value. Supply is possible. Therefore, even if the electron-emitting device 1 is increased in size, it is possible to apply a uniform voltage with almost no potential distribution in the surface of the thin film electrode 4.

  Further, since the fine particle layer 3 formed in the opening 6A of the electrical insulating layer 5 is composed of a mixture of the insulating fine particles 7A and the conductive fine particles 7B, the electric resistance of the electron-emitting device 1 can be easily and uniformly adjusted. It becomes possible. Therefore, the electron-emitting device 1 has a device configuration that can realize a large area. Accordingly, the electron-emitting device 1 has a large area and can maintain uniform electron emission in the surface direction for a long period of time.

DESCRIPTION OF SYMBOLS 1 Electron emission element 2 Electrode substrate 3 Fine particle layer 4 Thin film electrode 5 Electrical insulating layer 6 Opening 6A Opening 7A Insulating fine particle 7B Conductive fine particle 8 Amorphous carbon layer 9A Porous electrode layer 9B Solid electrode layer 10 Electron emission device 11 Power supply 12 Electrode Pad 13 Insulating spacer 14 Mesh counter electrode 15 Rectangular wave power source 16 DC power source 31 First fine particle layer 32 Second fine particle layer 41 Thin film electrode hole portion 41A Thin film electrode hole 51 Outer edge projection line

Claims (15)

A plate-like first electrode;
A second electrode formed opposite the first electrode;
An electrical insulating layer formed between the first electrode and the second electrode and having a plurality of openings filled with a fine particle layer containing insulating fine particles and conductive fine particles;
When a voltage is applied between the first electrode and the second electrode, electrons emitted from the first electrode pass through the fine particle layer, pass through the second electrode, and are emitted from the second electrode. An electron-emitting device comprising:   2. The electron-emitting device according to claim 1, wherein a shape of a cross section perpendicular to a depth direction of each opening formed in the electrical insulating layer is a square having one side of 10 μm to 500 μm.   The electron-emitting device according to claim 1, wherein the electrical insulating layer is made of an acrylic resin.   4. The electron emission according to claim 1, wherein the plurality of openings formed in the electrical insulating layer are disposed within a range in which the first electrode and the second electrode face each other. element.   5. The electron-emitting device according to claim 1, wherein the second electrode has a plurality of concave portions facing outward on a surface facing outward. 6.   The second electrode includes a first thin film electrode layer formed on the fine particle layer side and a second thin film electrode layer having a resistance value lower than that of the first thin film electrode layer and formed with the plurality of recesses. The electron-emitting device according to claim 5.   The electron-emitting device according to claim 6, wherein the second thin film electrode layer is electrically connected to the fine particle layer when the recess penetrates the first thin film electrode layer.   8. The electron-emitting device according to claim 6, wherein the first thin film electrode layer is an amorphous carbon layer.   The electron-emitting device according to any one of claims 6 to 8, wherein the second thin film electrode layer is a metal layer.   The electron-emitting device according to claim 9, wherein the metal layer includes at least one of gold, silver, tungsten, titanium, aluminum, and palladium.   The electron-emitting device according to any one of claims 1 to 10, wherein the fine particle layer further includes an insulating fine particle layer formed of insulating fine particles.   The electron-emitting device according to claim 1, wherein the insulating fine particles and the conductive fine particles contained in the fine particle layer are fixed by a silicon resin.   The conductive particles include at least one of gold, silver, platinum, palladium, and nickel, and have an average particle diameter of 3 to 10 nm. The electron-emitting device according to one.   The insulating fine particle includes at least one of silicon dioxide, aluminum oxide, and titanium dioxide, and has an average particle diameter of 10 to 1000 nm. The electron-emitting device described in 1. An electrically insulating layer forming step of forming an electrically insulating layer having a plurality of openings on the plate-like first electrode;
A fine particle layer forming step of forming a fine particle layer composed of conductive fine particles and insulating fine particles on the surface of the electric insulating layer formed in the electric insulating layer forming step;
A removal step of removing the fine particle layer formed on the surface of the electrically insulating layer excluding the opening;
The second electrode, which is a thin film electrode, is formed in a shape that conforms to the shape of the surface of the electrically insulating layer from which the fine particle layer has been removed and the shape of the surface of the fine particle layer filled in the opening formed by the opening. And a film process.