JP2010198850A - Electron emission element, electron emission device, charging device, image forming device, electron beam curing device self light-emitting device, image device, blower, cooling device, manufacturing method for electron emission element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electron emission element which can restrain deterioration of an electron acceleration layer and effectively enables stable electron emission at atmospheric pressure as well as in a vacuum and is formed by raising mechanical strength. <P>SOLUTION: The electron emission element 1 has the electron acceleration layer 4 between an electrode substrate 2 and a thin-film electrode 3. The electron acceleration layer 4 includes binder resin 15 wherein insulator fine particles 5 and conductive fine particles 6 are dispersed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electron-emitting device that emits electrons by applying a voltage.

  As a conventional electron-emitting device, a Spindt type electrode, a carbon nanotube (CNT) type electrode, and the like are known. Such an electron-emitting device has been studied for application in the field of FED (Field Emission Display), for example. In such an electron-emitting device, a voltage is applied to the sharp portion to form a strong electric field of about 1 GV / m, and electrons are emitted by the 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 region, the emitted electrons easily obtain a large energy by the electric field and easily ionize gas molecules. There is a problem that cations generated by ionization of gas molecules are accelerated and collided in the direction of the surface of the device by a strong electric field, and device destruction occurs due to sputtering. Moreover, since oxygen in the atmosphere has lower dissociation energy than ionization energy, ozone is generated prior to the generation of ions. Since ozone is harmful to the human body and oxidizes various things with its strong oxidizing power, there is a problem of damaging members around the element. To avoid this, the surrounding members are ozone resistant. There is a restriction that high material must be used.

  Therefore, MIM (Metal Insulator Metal) type and MIS (Metal Insulator Semiconductor) type electron emitting devices are known as other types of electron emitting devices. These are surface emission type electron-emitting devices that use the quantum size effect and strong electric field inside the device to accelerate electrons and emit electrons from the planar device surface. Since these emit electrons accelerated by the electron acceleration layer inside the device, a strong electric field is not required outside the device. Therefore, the MIM type and MIS type electron-emitting devices have a problem that they are destroyed by sputtering due to ionization of gas molecules, and ozone is generated, like the Spindt-type, CNT-type, and BN-type electron-emitting devices. It can be overcome. In order to increase the mechanical strength of such an electron-emitting device, for example, in Patent Document 1, as an electron acceleration layer, a powder layer composed of a plurality of insulator particles and an oxide insulation covering the powder layer are disclosed. An electron-emitting device provided with a fixed layer made of a body is disclosed.

JP 2000-31640 A (published November 7, 2000)

  However, when the above-mentioned conventional electron emission device of MIM type or MIS type is operated in the atmosphere, various gas molecules are adsorbed on the surface of the device, and the electric characteristics of the electron acceleration layer are altered, resulting in an electron emission current. There is a new problem of decrease.

  The surface of these conventional electron emission devices of MIM type and MIS type that accelerate electrons by these electron acceleration layers plays the role of an upper electrode (thin film electrode) that applies an electric field to the electron acceleration layer. It consists of Further, the surface of the conventional electron-emitting device of the MIM type or the MIS type also plays a role of causing electrons accelerated by the electron acceleration layer to tunnel through the metal thin film and emit into the vacuum. The smaller the thickness, the higher the tunnel probability of electrons accelerated by the electron acceleration layer, and the more the electron emission. Therefore, it can be said that the metal thin film is preferably thin. However, if the metal thin film is too thin, it is difficult to form a dense film, so that there is almost no gas molecule barrier effect. Therefore, when the electron-emitting device is operated in the atmosphere, there is a problem that gas molecules enter the internal electron acceleration layer, change the electrical characteristics of the electron acceleration layer, and reduce the electron emission current.

  As a result, electrons cannot be stably generated in the atmosphere, and especially when the electron acceleration layer contains conductive fine particles, the oxidation of the conductive fine particles proceeds due to oxygen in the atmosphere, deteriorating the electron acceleration layer. The electron emission stops.

  Furthermore, if the electron acceleration layer contains fine particles, and its dispersibility is poor and it is an aggregate, the performance of the device will not be uniform and stable electron supply will not be possible. Further, as in Patent Document 1, when the electron acceleration layer contains insulating particles, the surface of the electron acceleration layer becomes uneven, and it is difficult to form a thin metal thin film thereon. Therefore, it is preferable that the metal thin film is thin as described above. However, if the metal thin film cannot be formed so thin, electrons cannot be efficiently emitted.

  The present invention has been made in view of the above problems, and can suppress deterioration of the electron acceleration layer, enable efficient and stable electron emission not only in a vacuum but also in an atmospheric pressure, and formed with increased mechanical strength. An object is to provide an electron-emitting device or the like.

  In order to solve the above-described problems, an electron-emitting device of the present invention has an electrode substrate, a thin film electrode, the electrode substrate, and an electron acceleration layer sandwiched between the thin film electrodes. When a voltage is applied between them, the electron accelerating layer accelerates the electrons and emits the electrons from the thin film electrode. The electron accelerating layer includes an insulator material and conductive fine particles dispersed therein. It is characterized by containing the resin binder made.

  According to the above configuration, the electron acceleration layer including the resin binder in which the insulator substance and the conductive fine particles are dispersed is provided between the electrode substrate and the thin film electrode. This electron acceleration layer is a thin film layer in which an insulating substance and conductive fine particles are dispersed in a resin binder, and has semiconductivity. When a voltage is applied to the semiconductive electron acceleration layer, a current flows in the electron acceleration layer, and a part thereof is emitted as ballistic electrons by the strong electric field formed by the applied voltage. Here, since the conductive fine particles are dispersed in the binder resin, that is, the binder resin exists around the conductive fine particles, it is difficult to cause element degradation due to oxidation by oxygen in the atmosphere. Therefore, it can be stably operated not only in a vacuum but also in an atmospheric pressure.

  In addition, since the insulator substance and the conductive fine particles are dispersed in the resin binder, aggregation hardly occurs, the device performance becomes uniform, and stable electron supply is possible. Further, the resin binder has high adhesiveness with the electrode substrate and high mechanical strength. Furthermore, the resin binder can improve the smoothness of the surface of the electron acceleration layer, and the thin film electrode thereon can be formed thin. Therefore, in the electron-emitting device of the present invention, the electron acceleration layer can be a thin film in which the insulator substance and the conductive fine particles are almost uniformly diffused, and the performance is uniform and the mechanical strength is high.

  As described above, the electron-emitting device of the present invention can suppress the deterioration of the electron acceleration layer, and enables efficient and stable electron emission not only in vacuum but also at atmospheric pressure. Furthermore, the electron-emitting device of the present invention can increase the mechanical strength.

  In the electron-emitting device of the present invention, in addition to the above configuration, the conductive fine particles may be a conductor having high anti-oxidation power.

  Here, the high antioxidant power mentioned here indicates that the oxide formation reaction is low. In general, the larger the negative value ΔG [kJ / mol] value of the oxide formation free energy obtained by thermodynamic calculation, the easier the oxide formation reaction occurs. In the present invention, a metal element corresponding to ΔG> −450 [kJ / mol] or more corresponds to conductive fine particles having a high antioxidant power. In addition, the conductive fine particles in a state in which an oxide generation reaction is more difficult to occur by attaching or coating an insulating material smaller than the size of the conductive fine particles around the corresponding conductive fine particles have anti-oxidation power. Included in high conductive particles.

  According to the above configuration, since a conductive material having high anti-oxidation power is used as the conductive fine particles, it is difficult to cause device deterioration due to oxidation by oxygen in the atmosphere, so that the electron-emitting device can be operated more stably even at atmospheric pressure. Can do. Therefore, the lifetime can be extended and continuous operation can be performed for a long time even in the atmosphere.

  In the electron-emitting device of the present invention, in addition to the above configuration, the conductive fine particles may be a noble metal. As described above, since the conductive fine particles are precious metals, it is possible to prevent element deterioration such as oxidation of the conductive fine particles by oxygen in the atmosphere. Therefore, the lifetime of the electron-emitting device can be extended.

  In the electron-emitting device of the present invention, in addition to the above configuration, the conductor constituting the conductive fine particles may include at least one of gold, silver, platinum, palladium, and nickel. As described above, the conductive material forming the conductive fine particles contains at least one of gold, silver, platinum, palladium, and nickel, so that the conductive fine particles are oxidized by oxygen in the atmosphere. Deterioration can be prevented more effectively. Therefore, the lifetime of the electron-emitting device can be extended more effectively.

  In the electron-emitting device of the present invention, in addition to the above-described configuration, the average diameter of the conductive fine particles must be smaller than the size of the insulator substance because it is necessary to control conductivity, and is 3 to 10 nm. preferable. Thus, by setting the average diameter of the conductive fine particles to be smaller than the fine particle diameter of the insulator substance, preferably 3 to 10 nm, a conductive path by the conductive fine particles is not formed in the electron acceleration layer, and the electrons Dielectric breakdown is less likely to occur in the acceleration layer. Although there are many unclear points in principle, ballistic electrons are efficiently generated by using conductive fine particles having a particle diameter within the above range.

In the electron-emitting device of the present invention, in addition to the above configuration, the insulator substance may include at least one of SiO ₂ , Al ₂ O ₃ , and TiO ₂ . Or it may contain an organic polymer. If the insulator material contains at least one of SiO ₂ , Al ₂ O ₃ , and TiO ₂ , or contains an organic polymer, the insulating property of these materials is high. It is possible to adjust the resistance value to an arbitrary range. In particular, when an oxide (SiO ₂ , Al ₂ O ₃ , and TiO ₂ ) is used as an insulator substance and a conductor having high anti-oxidation power is used as a conductive fine particle, an element accompanying oxidation by oxygen in the atmosphere Since the deterioration is less likely to occur, the effect of stably operating even at atmospheric pressure can be exhibited more significantly.

  Here, the insulator substance may be fine particles, and the average diameter is preferably 10 to 1000 nm, and more preferably 12 to 110 nm. In this case, the dispersion state of the particle diameter may be broad with respect to the average particle diameter. For example, fine particles having an average particle diameter of 50 nm may have a particle diameter distribution in the region of 20 to 100 nm. By making the average diameter of the insulating substance, which is the fine particles, preferably 10 to 1000 nm, more preferably 12 to 110 nm, heat conduction is efficiently conducted from the inside to the outside of the conductive fine particles that are smaller than the size of the insulating substance. Thus, Joule heat generated when current flows in the device can be efficiently released, and the electron-emitting device can be prevented from being destroyed by heat. Furthermore, the resistance value in the electron acceleration layer can be easily adjusted.

  In the electron-emitting device of the present invention, in addition to the above configuration, the ratio of the conductive fine particles in the electron acceleration layer is preferably 0.5 to 30% by weight. When the amount is less than 0.5%, the effect of increasing the current in the device as conductive fine particles is not exhibited, and when the amount is more than 30%, aggregation of the conductive fine particles occurs. Among these, 2 to 20% is more preferable.

  In the electron-emitting device of the present invention, in addition to the above configuration, the thickness of the electron acceleration layer is preferably 12 to 6000 nm, and more preferably 300 to 6000 nm. By making the layer thickness of the electron acceleration layer preferably 12 to 6000 nm, more preferably 300 to 6000 nm, the electron acceleration layer can be made uniform, and the resistance of the electron acceleration layer can be adjusted in the layer thickness direction. It becomes possible. As a result, electrons can be uniformly emitted from the entire surface of the electron-emitting device, and electrons can be efficiently emitted outside the device.

  In the electron-emitting device of the present invention, in addition to the above configuration, the thin film electrode may include at least one of gold, silver, carbon, tungsten, titanium, aluminum, and palladium. By containing at least one of gold, silver, carbon, tungsten, titanium, aluminum, and palladium in the thin film electrode, electrons generated in the electron acceleration layer are efficiently tunneled due to the low work function of these materials. Thus, more high-energy electrons can be emitted outside the electron-emitting device.

  In the electron-emitting device of the present invention, in addition to the above configuration, an insulating material smaller than the size of the conductive fine particles may exist around the conductive fine particles. As described above, the presence of an insulating material smaller than the size of the conductive fine particles around the conductive fine particles contributes to the improvement in dispersibility of the conductive fine particles in the dispersion liquid at the time of device preparation. Further, it is possible to more effectively prevent device deterioration including oxidation due to oxygen in the atmosphere. Therefore, the lifetime of the electron-emitting device can be extended more effectively.

  In the electron-emitting device of the present invention, in addition to the above configuration, the insulator material smaller than the size of the conductive fine particles present around the conductive fine particles may include at least one of alcoholate, fatty acid, and alkanethiol. . As described above, since the insulator material smaller than the size of the conductive fine particles existing around the conductive fine particles contains at least one of alcoholate, fatty acid, and alkanethiol, the dispersion of the conductive fine particles at the time of device preparation is achieved. In order to contribute to the improvement of dispersibility in the liquid, the formation of abnormal paths of the current caused by the aggregates of the conductive fine particles is made difficult, and the composition of the particles accompanying the oxidation of the conductive fine particles themselves existing around the insulator substance Since no change occurs, the electron emission characteristics are not affected. Therefore, the lifetime of the electron-emitting device can be extended more effectively.

  Here, in the electron-emitting device of the present invention, the insulator material smaller than the size of the conductive fine particles existing around the conductive fine particles is attached to the surface of the conductive fine particles and exists as an attached substance. The substance may coat the surface of the conductive fine particles as an aggregate having a shape smaller than the average diameter of the conductive fine particles. As described above, the surface of the conductive fine particles is formed as an aggregate in which an insulating substance smaller than the size of the conductive fine particles existing around the conductive fine particles adheres to the surface of the conductive fine particles or has a shape smaller than the average diameter of the conductive fine particles. In order to contribute to improving the dispersibility of the conductive fine particles in the dispersion liquid at the time of device preparation, it is difficult to form an abnormal current path due to the aggregate of the conductive fine particles. Since there is no change in the composition of the particles accompanying the oxidation of the conductive fine particles themselves existing around the substance, the electron emission characteristics are not affected. Therefore, the lifetime of the electron-emitting device can be further effectively increased.

  The electron-emitting device of the present invention includes any one of the above-described electron-emitting devices and a power supply unit that applies a voltage between the electrode substrate and the thin-film electrode.

  According to the above configuration, it is possible to ensure electrical continuity, flow a sufficient in-device current, and efficiently and stably emit ballistic electrons from the thin film electrode.

  Furthermore, by using the electron-emitting device of the present invention for a self-light-emitting device and an image display apparatus provided with the self-light-emitting device, a self-light-emitting device that realizes stable and long-life surface light emission can be provided.

  In addition, by using the electron-emitting device of the present invention in a blower or a cooling device, no discharge occurs, no harmful substances such as ozone and NOx are generated, and the slip effect on the surface of the object to be cooled is used. By doing so, it is possible to cool with high efficiency.

  Further, by using the electron-emitting device of the present invention in a charging device and an image forming apparatus equipped with the charging device, the discharge is not accompanied and no harmful substances such as ozone and NOx are generated. The object to be charged can be charged stably for a period.

  In addition, by using the electron-emitting device of the present invention in an electron beam curing apparatus, the electron beam can be cured in terms of area, maskless can be achieved, and cost reduction and high throughput can be realized.

  In order to solve the above problems, the method for manufacturing an electron-emitting device of the present invention includes an electrode substrate, a thin film electrode, the electrode substrate, and an electron acceleration layer sandwiched between the thin film electrode, and the electrode substrate and the thin film. When a voltage is applied between the electrodes, the electron acceleration layer accelerates the electrons to emit the electrons from the thin film electrode, and the insulator material is dispersed in the resin binder. A dispersion adjusting step for adjusting the dispersion, a mixture adjusting step for adjusting a mixture in which conductive fine particles are dispersed in the dispersion, and the electron acceleration by applying the mixture on the electrode substrate. And an electron acceleration layer forming step of forming a layer.

  According to the above method, an electron acceleration layer is provided on an electrode substrate by applying a mixed liquid in which an insulating substance and conductive fine particles are dispersed in a resin binder. As a result, it is possible to obtain an element with high mechanical strength that has a uniform performance and enables efficient and stable electron emission by covering the electrode substrate with an insulating material and conductive fine particles thinly and uniformly.

  In the electron-emitting device of the present invention, as described above, the electron acceleration layer includes a resin binder in which an insulating material and conductive fine particles are dispersed.

  This electron acceleration layer is a thin film layer in which an insulating substance and conductive fine particles are dispersed in a resin binder, and has semiconductivity. When a voltage is applied to the semiconductive electron acceleration layer, a current flows in the electron acceleration layer, and a part thereof is emitted as ballistic electrons by the strong electric field formed by the applied voltage. Here, since the conductive fine particles are dispersed in the binder resin, that is, the binder resin exists around the conductive fine particles, it is difficult to cause element degradation due to oxidation by oxygen in the atmosphere. Therefore, it can be stably operated not only in a vacuum but also in an atmospheric pressure.

  In addition, since the insulator substance and the conductive fine particles are dispersed in the resin binder, aggregation hardly occurs, the device performance becomes uniform, and stable electron supply is possible. Further, the resin binder has high adhesiveness with the electrode substrate and high mechanical strength. Therefore, in the electron-emitting device of the present invention, the electron acceleration layer can be a thin film in which the insulator substance and the conductive fine particles are almost uniformly diffused, and the performance is uniform and the mechanical strength is high.

  As described above, the electron-emitting device of the present invention can suppress the deterioration of the electron acceleration layer, and enables efficient and stable electron emission not only in vacuum but also at atmospheric pressure. Furthermore, the electron-emitting device of the present invention can increase the mechanical strength.

It is a schematic diagram which shows the structure of the electron-emitting element of one Embodiment of this invention. FIG. 2 is an enlarged view of a cross section in the vicinity of an electron acceleration layer in the electron-emitting device of FIG. 1. It is a figure which shows the measurement system of an electron emission experiment. It is a figure which shows an example of the charging device using the electron-emitting element of this invention. It is a figure which shows an example of the electron beam hardening apparatus using the electron-emitting element of this invention. It is a figure which shows an example of the self-light-emitting device using the electron-emitting element of this invention. It is a figure which shows another example of the self-light-emitting device using the electron-emitting element of this invention. It is a figure which shows another example of the self-light-emitting device using the electron-emitting element of this invention. It is a figure which shows another example of the image display apparatus which comprises the self-light-emitting device using the electron-emitting element of this invention. It is a figure which shows an example of the air blower using the electron-emitting element which concerns on this invention, and a cooling device provided with the same. It is a figure which shows another example of the air blower using the electron-emitting element of this invention, and a cooling device provided with the same.

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

[Embodiment 1]
FIG. 1 is a schematic diagram showing the configuration of an embodiment of an electron-emitting device of the present invention. As shown in FIG. 1, an electron-emitting device 1 according to this embodiment includes an electrode substrate 2 that is a lower electrode, a thin film electrode 3 that is an upper electrode, and an electron acceleration layer 4 that is sandwiched therebetween. In addition, the electrode substrate 2 and the thin film electrode 3 are connected to a power source 7 so that a voltage can be applied between the electrode substrate 2 and the thin film electrode 3 arranged to face each other. The electron-emitting device 1 applies a voltage between the electrode substrate 2 and the thin film electrode 3, thereby passing a current between the electrode substrate 2 and the thin film electrode 3, that is, the electron acceleration layer 4. The thin film electrode 3 is transmitted and / or emitted from the gap between the thin film electrodes 3 as ballistic electrons by the strong electric field formed by the applied voltage. The electron emission device 10 is composed of the electron emission element 1 and the power source 7.

  The electrode substrate 2 serving as the lower electrode serves as a support for the electron-emitting device. Therefore, any material can be used without particular limitation as long as it has a certain degree of strength, has good adhesion to a directly contacting substance, and has appropriate conductivity. Examples thereof include metal substrates such as SUS, Ti, and Cu, semiconductor substrates such as Si, Ge, and GaAs, insulator substrates such as glass substrates, and plastic substrates. For example, if an insulating substrate such as a glass substrate is used, a conductive substance such as a metal is attached to the interface with the electron acceleration layer 4 as an electrode, so that it can be used as the electrode substrate 2 serving as a lower electrode. . The conductive material is not particularly limited as long as a material having excellent conductivity can be formed into a thin film using magnetron sputtering or the like, but its constituent material is not particularly limited. It is preferable to use a conductor having a high thickness, and it is more preferable to use a noble metal. An ITO thin film widely used for transparent electrodes is also useful as an oxide conductive material. In addition, for example, a metal thin film in which a Ti film is formed to 200 nm on a glass substrate surface and a Cu film is further formed to a 1000 nm thickness may be used in that a tough thin film can be formed. Never happen.

  The thin film electrode 3 applies a voltage in the electron acceleration layer 4. Therefore, any material that can be applied with voltage can be used without particular limitation. However, from the standpoint that electrons accelerated and become high energy in the electron acceleration layer 4 are transmitted with as little energy loss as possible and emitted, a material having a low work function and capable of forming a thin film is higher. The effect can be expected. Examples of such a material include gold, silver, carbon, tungsten, titanium, aluminum, palladium, and the like whose work function corresponds to 4 to 5 eV. In particular, assuming operation at atmospheric pressure, gold without oxide and sulfide formation reaction is the best material. In addition, silver, palladium, tungsten, and the like, which have a relatively small oxide formation reaction, are materials that can withstand actual use without problems. The film thickness of the thin-film electrode 3 is important as a condition for efficiently emitting electrons from the electron-emitting device 1 to the outside, and is preferably in the range of 10 to 55 nm. The minimum film thickness for causing the thin film electrode 3 to function as a planar electrode is 10 nm. If the film thickness is less than this, electrical conduction cannot be ensured. On the other hand, the maximum film thickness for emitting electrons from the electron-emitting device 1 to the outside is 55 nm. If the film thickness exceeds this, no ballistic electrons are transmitted, and the thin-film electrode 3 accelerates electrons by absorbing or reflecting ballistic electrons. Recapture into layer 4 will occur.

  As shown in FIG. 2, the electron acceleration layer 4 only needs to include a binder resin 15 in which an insulator material 5 and conductive fine particles 6 are dispersed. In the present embodiment, the electron acceleration layer 4 includes a binder resin 15 in which insulating fine particles 5 and conductive fine particles 6 are dispersed as the insulating material 5.

  The size of the insulating fine particles 5 is preferably larger than the diameter of the conductive fine particles 6 in order to obtain a heat radiation effect superior to that of the conductive fine particles 6, and the diameter (average diameter) of the insulating fine particles 5 is 10 to 1000 nm. It is preferable that it is 12-110 nm.

Materials of the insulating fine particles 5 such thing as _{SiO 2, Al 2 O 3,} TiO 2 becomes practical. However, using small-sized silica particles with surface treatment increases the surface area of the silica particles in the solvent and increases the solution viscosity compared to using spherical silica particles with a larger particle diameter. Therefore, the film thickness of the electron acceleration layer 4 tends to increase slightly. The material of the insulating fine particles 5 may be fine particles made of an organic polymer. For example, highly crosslinked fine particles (SX8743) made of styrene / divinylbenzene manufactured and sold by JSR Corporation, or manufactured by Nippon Paint Corporation. The fine sphere series of styrene / acrylic fine particles to be sold is available. Here, the insulating fine particles 5 may use two or more kinds of different particles, may use particles having different particle size peaks, or have a single particle and a broad distribution of particle sizes. May be used.

  As the material of the conductive fine particles 6, any conductor can be used on the principle of operation of generating ballistic electrons. However, for the purpose of avoiding oxidative degradation when operated at atmospheric pressure, it is necessary to be a conductor having high anti-oxidation power, and a noble metal is preferable, and examples thereof include materials such as gold, silver, platinum, palladium, and nickel. Such conductive fine particles 6 can be prepared using a known fine particle production technique such as sputtering or spray heating, and also use commercially available metal fine particle powders such as silver nanoparticles produced and sold by Applied Nano Laboratory. Is possible. The principle of ballistic electron generation will be described later.

  Here, since it is necessary to control the conductivity, the average diameter of the conductive fine particles 6 must be smaller than the size of the insulating fine particles 5 described below, and is more preferably 3 to 10 nm. Thus, by setting the average diameter of the conductive fine particles 6 to be smaller than the particle diameter of the insulating fine particles 5, preferably 3 to 10 nm, a conductive path by the conductive fine particles 6 is not formed in the electron acceleration layer 4. Insulation breakdown in the electron acceleration layer 4 hardly occurs. Although there are many unclear points in principle, ballistic electrons are efficiently generated by using the conductive fine particles 6 having a particle diameter in the above range.

  The proportion of the conductive fine particles 6 in the entire electron acceleration layer 4 is preferably 0.5 to 30% by weight. When the amount is less than 0.5% by weight, the effect of increasing the current in the device as conductive fine particles is not exhibited, and when the amount is more than 30% by weight, aggregation of the conductive fine particles occurs. Especially, it is more preferable that it is 1 to 10 weight%.

  Note that a small insulator material, which is an insulator material smaller than the size of the conductive fine particles 6, may exist around the conductive fine particles 6, and the small insulator material adheres to the surface of the conductive fine particles 6. The substance may be a substance, and the attached substance may be an insulating film that coats the surface of the conductive fine particles 6 as an aggregate having a shape smaller than the average diameter of the conductive fine particles 6. As the small insulator material, any insulator material can be used on the principle of operation of generating ballistic electrons. However, when the insulating material smaller than the size of the conductive fine particle 6 is an insulating film that coats the conductive fine particle 6, and the insulating film is covered by the oxide film of the conductive fine particle 6, the thickness of the oxide film due to oxidative degradation in the atmosphere. In order to avoid oxidative degradation when operated at atmospheric pressure, an insulating film made of an organic material is preferable. For example, materials such as alcoholate, fatty acid, and alkanethiol are listed. It is done. It can be said that the thinner the insulating coating, the more advantageous.

  The resin binder 15 is not particularly limited as long as it has good adhesion to the substrate electrode 2, can disperse the insulating fine particles 5 and the conductive fine particles 6, and has insulating properties. Examples of such a resin binder 15 include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltriethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, hydrolyzable group-containing siloxane, Vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxy Propyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysila N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-tri Ethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropyltri Examples include methoxysilane, bis (triethoxysilylpropyl) tetrasulfide, and 3-isocyanatopropyltriethoxysilane. These resin binders can be used alone or in combination of two or more.

  When the electron acceleration layer 4 on the electrode substrate 2 is composed of conductive fine particles and insulator fine particles, the opportunity strength is weak, and a thin film electrode may be provided on the electrode acceleration layer 4 and it is fragile, so that electron emission is unstable. Become. However, when the conductive fine particles and the insulating fine particles are dispersed in the binder resin 15, the mechanical strength of the electron-emitting device 1 is increased because the resin binder 15 has high adhesion to the electrode substrate 2 and high mechanical strength. Further, when the conductive fine particles and the insulating fine particles are dispersed in the resin binder 15, aggregation hardly occurs. Therefore, the performance of the electron-emitting device 1 becomes uniform, and stable electron supply is possible. Further, the binder resin 15 can improve the smoothness of the surface of the electron acceleration layer 4 and the thin film electrode 3 thereon can be formed thin.

  As the electron acceleration layer 4 is thinner, a stronger electric field is applied, so that electrons can be accelerated by applying a low voltage. However, the thickness of the layer can be made uniform and the resistance of the electron acceleration layer in the thickness direction can be adjusted. The layer thickness of the electron acceleration layer 4 is preferably 12 to 6000 nm, and more preferably 300 to 6000 nm.

  Next, the principle of electron emission will be described. FIG. 2 is an enlarged schematic view of the cross section near the electron acceleration layer 4 of the electron-emitting device 1. As shown in FIG. 2, most of the electron acceleration layer 4 is composed of the insulating fine particles 5 and the binder resin 15, and the conductive fine particles 6 are scattered in the gaps. Since the electron acceleration layer 4 is composed of the insulating fine particles 5 and the binder resin 15 and a small number of conductive fine particles 6, it has semiconductivity. Therefore, when a voltage is applied to the electron acceleration layer 4, a very weak current flows. The voltage-current characteristic of the electron acceleration layer 4 shows a so-called varistor characteristic, and the current value is rapidly increased as the applied voltage increases. Part of this current becomes ballistic electrons due to the strong electric field in the electron acceleration layer 4 formed by the applied voltage, passes through the thin film electrode 3 and / or passes through the gap, and is emitted to the outside of the electron-emitting device 1. The formation process of ballistic electrons is thought to be due to electrons tunneling while being accelerated in the direction of the electric field, but it has not been determined.

  As described above, in the electron-emitting device 1, the electron acceleration layer 4 is a thin film layer in which the insulating fine particles 5 and the conductive fine particles 6 are dispersed in the resin binder 15. Here, since the conductive fine particles 4 are dispersed in the binder resin, that is, the binder resin 15 exists around the conductive fine particles 4, it is difficult to cause element degradation due to oxidation by oxygen in the atmosphere. Therefore, the electron-emitting device 1 can be stably operated not only in a vacuum but also in an atmospheric pressure. Further, since the insulator material 5 and the conductive fine particles 6 are dispersed in the resin binder 15, aggregation hardly occurs, the performance of the electron-emitting device 1 becomes uniform, and the electron-emitting device 1 can stably supply electrons. is there. Moreover, the resin binder 15 has high adhesiveness with the electrode substrate 2 and high mechanical strength. Further, the resin binder 15 can make the surface of the electron acceleration layer 4 uneven, and the thin film electrode 3 thereon can be formed thin.

  Therefore, in the electron-emitting device 1, the electron acceleration layer 4 can be a thin film in which the insulator material 5 and the conductive fine particles 6 are almost uniformly diffused, and the performance is uniform and the mechanical strength is high.

  Thus, the electron-emitting device 1 can suppress the deterioration of the electron acceleration layer 4 and can efficiently and stably emit electrons not only in a vacuum but also at atmospheric pressure. Furthermore, the electron-emitting device 1 can increase the mechanical strength simply and inexpensively.

  Next, an embodiment of a manufacturing method of the electron-emitting device 1 will be described.

  First, an insulator substance-containing resin binder dispersion dispersed in an insulator substance 5, a resin binder 15, and an organic solvent is obtained. The organic solvent used here can be used without particular limitation as long as it can disperse the insulator material 5 and the resin binder 15 and can be dried after coating. For example, methanol, ethanol, propanol, 2-propanol, butanol, Examples include 2-butanol. These organic solvents can be used alone or in combination of two or more. The dispersion method is not particularly limited, and for example, it can be dispersed by applying an ultrasonic disperser at room temperature. The content of the insulator substance is preferably 3 to 50% by weight. When the amount is less than 3% by weight, the effect of adjusting the resistance of the electron acceleration layer 4 as an insulator is not exhibited. Especially, it is more preferable that it is 20-30 weight%.

  Next, the conductive fine particle solution is mixed with the insulator substance-containing resin binder solution obtained as described above to obtain an insulator substance and conductive fine particle mixed solution. The mixing method is not particularly limited, and may be stirred at room temperature, for example. Here, when the conductive fine particles are in the form of powder during the mixing, it is preferable to use a conductive fine particle solution dispersed in an organic solvent. The organic solvent can be used without particular limitation as long as the conductive fine particles 6 can be dispersed and dried after coating, and examples thereof include hexane and toluene. The content of the conductive fine particles is preferably 0.5 to 30% by weight. When the amount is less than 1% by weight, the effect of increasing the current in the device as conductive fine particles is not exhibited, and when the amount is more than 30% by weight, aggregation of the conductive fine particles occurs. Especially, it is more preferable that it is 2 to 20 weight%.

  The electron acceleration layer 4 is formed by applying the insulating material and the conductive fine particle mixed solution formed as described above onto the electrode substrate 2 by using a spin coating method. A predetermined film thickness can be obtained by repeating film formation and drying by a spin coating method a plurality of times. The electron acceleration layer 4 can be formed by a method such as a dropping method or a spray coating method in addition to the spin coating method. Then, the thin film electrode 3 is formed on the electron acceleration layer 4. For forming the thin film electrode 3, for example, a magnetron sputtering method may be used. The thin film electrode 3 may be formed by using, for example, an ink jet method, a spin coat method, a vapor deposition method, or the like.

(Example)
In the following examples, an experiment in which current measurement is performed using the electron-emitting device according to the present invention will be described. In addition, this experiment is an example of implementation and does not limit the content of the present invention.

First, the electron-emitting devices of Examples 1 to 4 were produced as follows. And about the created electron emission element of Examples 1-4, the measurement experiment of the electron emission current per unit area was conducted using the experimental system shown in FIG. In the experimental system of FIG. 3, the counter electrode 8 is disposed on the thin film electrode 3 side of the electron-emitting device 1 with the insulator spacer 9 interposed therebetween. The electron-emitting device 1 and the counter electrode 8 are each connected to a power source 7, and a voltage V1 is applied to the electron-emitting device 1 and a voltage V2 is applied to the counter electrode 8. An electron emission experiment was conducted by placing such an experimental system in a vacuum of 1 × 10 ⁻⁸ ATM. In the experiment, the distance between the electron-emitting device and the counter electrode was 5 mm with the insulator spacer 9 interposed therebetween.

Example 1
First, 2.0 g of ethanol solvent and 0.5 g of tetramethoxysilane KBM-04 (manufactured by Shin-Etsu Chemical Co., Ltd.) are placed in a 10 mL reagent bottle, and spherical silica particles AEROSIL R8200 (Evonik EXASA) having an average diameter of 12 nm are used as the insulator material 5. (Japan Co., Ltd.) was introduced in an amount of 0.5 g, and the reagent bottle was put on an ultrasonic dispersing device to prepare an insulating substance-containing resin binder dispersion A. The content of the insulator substance in the dispersion A was 17% by weight.

  The dispersion A thus obtained and the conductive fine particle solution containing the conductive fine particles 6 were mixed. As the conductive fine particle solution containing the conductive fine particles 6, a silver nanoparticle-containing hexane dispersion solution (manufactured by Applied Nanoparticles Laboratory, average particle diameter of silver fine particles 4.5 nm, silver fine particle solid content concentration 7%) was used. 1.0 g of a hexane dispersion containing silver nanoparticles was added to 1.0 g of an insulating substance-containing resin binder dispersion A and stirred at room temperature to obtain an insulating substance and conductive fine particle mixed solution B. The content of the conductive fine particles 6 in the mixed solution B was 4.5% by weight.

  On the 30 mm square SUS substrate as the electrode substrate 2, after dropping the mixed solution B obtained above, an insulator material and a conductive fine particle-containing resin binder are deposited at 8000 rpm for 10 s using a spin coating method, and an electron acceleration layer 4 was obtained. The film thickness of the electron acceleration layer 4 was about 0.81 μm.

An electron-emitting device of Example 2 was obtained by forming a thin film electrode 3 on the surface of the electron acceleration layer 4 using a magnetron sputtering apparatus. Gold was used as the film forming material for the thin film electrode 3, the layer thickness of the thin film electrode 3 was 30 nm, and the area was 0.014 cm ² .

When the experimental system of FIG. 3 using this electron-emitting device was set to an applied voltage V1 = 27.4V to the thin film electrode and an applied voltage V2 = 100V to the counter electrode in a vacuum of 1 × 10 ⁻⁸ ATM, An electron emission current of 0.21 mA / cm ² per unit area was confirmed.

(Example 2)
Dispersion A obtained in the same manner as in Example 1 was mixed with a conductive fine particle solution containing conductive fine particles 6. As the conductive fine particle solution containing the conductive fine particles 6, a gold nanoparticle-containing naphthene dispersion solution (manufactured by Harima Chemicals Co., Ltd., average particle diameter of gold fine particles of 5.0 nm, solid concentration of gold fine particles of 52%) was used. 0.68 g of a gold nanoparticle-containing naphthene dispersion solution was added to 3.0 g of dispersion A and stirred at room temperature to obtain an insulator substance and conductive fine particle mixed solution C. The content of the conductive fine particles 6 in the mixed solution C was 9.6% by weight.

  After the mixed solution C obtained above was dropped onto a 30 mm square SUS substrate as the electrode substrate 2, the insulator material and the conductive fine particle-containing resin binder were deposited at 3000 rpm and 10 s using a spin coating method, and the electron acceleration layer 4 was obtained. The film thickness of the electron acceleration layer 4 was about 1.6 μm.

An electron-emitting device of Example 3 was obtained by forming a thin film electrode 3 on the surface of the electron acceleration layer 4 using a magnetron sputtering apparatus. Gold was used as a film forming material for the thin film electrode 3, the layer thickness of the thin film electrode 3 was 40 nm, and the area was 0.014 cm ² .

When the experimental system of FIG. 3 using this electron-emitting device was applied in a vacuum of 1 × 10 ⁻⁸ ATM, the applied voltage V1 = 27.5V to the thin film electrode and the applied voltage V2 = 100V to the counter electrode were: An electron emission current of 0.39 mA / cm ² per unit area was confirmed.

(Example 3)
Into a 10 mL reagent bottle, 2.5 g of methanol solvent and 0.5 mL of methyltrimethoxysilane KBM-13 (manufactured by Shin-Etsu Chemical Co., Ltd.) are added, and spherical silica particles AEROSIL RX200 having an average diameter of 12 nm as an insulator material 5 (Evonik EXA Japan) 0.5 g of Co., Ltd. was added, the reagent bottle was put on an ultrasonic disperser, and an insulating substance-containing resin binder dispersion D was prepared. The content of the insulating material in the dispersion D was 14% by weight.

  Into a 10 mL reagent bottle, 2.5 g of toluene solvent is added, 0.5 g of silver nanoparticles (Applied Nanoparticles Laboratory, average particle diameter of silver fine particles 10 nm) are added as conductive fine particles 6, and the reagent bottle is an ultrasonic disperser. And conductive fine particle solution E was prepared.

  The conductive fine particle solution E1.0 g was added to the obtained dispersion D1.0 g and stirred at room temperature to obtain an insulating material and a conductive fine particle mixed solution F. The content of the conductive fine particles 6 in the mixed solution F was 8.3% by weight.

  On the 30 mm square SUS substrate as the electrode substrate 2, after dropping the mixed solution F obtained above, an insulator material and a conductive fine particle-containing resin binder are deposited at 6000 rpm for 10 s by using a spin coating method, and an electron acceleration layer is formed. 4 was obtained. The film thickness of the electron acceleration layer 4 was about 1.2 μm.

An electron-emitting device of Example 4 was obtained by forming a thin film electrode 3 on the surface of the electron acceleration layer 4 using a magnetron sputtering apparatus. Gold was used as a film forming material for the thin film electrode 3, the layer thickness of the thin film electrode 3 was 40 nm, and the area was 0.014 cm ² .

When the experimental system of FIG. 3 using this electron-emitting device was set to an applied voltage V1 = 20.0 V to the thin film electrode and an applied voltage V2 = 100 V to the counter electrode in a vacuum of 1 × 10 ⁻⁸ ATM, An electron emission current of 1.00 mA / cm ² per unit area was confirmed.

Example 4
Ethanol solvent 2.5 g and tetramethoxysilane KBM-04 (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.5 g are put into a 10 mL reagent bottle, and spherical silica particles EP-C413 (Cabot Corporation) having an average diameter of 50 nm are used as the insulator material 5. Product) was put in, and the reagent bottle was put on an ultrasonic dispersing device to prepare an insulating substance-containing resin binder dispersion G. The content of the insulating material 5 in the dispersion G was 14% by weight.

  As the conductive fine particle solution containing the conductive fine particles 6, a gold nanoparticle-containing naphthene dispersion solution (manufactured by Harima Chemicals Co., Ltd., average particle diameter of gold fine particles of 5.0 nm, solid concentration of silver fine particles of 52%) was used. 0.68 g of a gold nanoparticle-containing naphthene dispersion solution was added to 3.0 g of dispersion G and stirred at room temperature to obtain an insulator substance and conductive fine particle mixed solution H. The content of the conductive fine particles in the mixed solution H was 9.6% by weight.

  On the 30 mm square SUS substrate as the electrode substrate 2, after dropping the mixed solution H obtained above, an insulator material and a conductive fine particle-containing resin binder are deposited at 3000 rpm for 10 s using a spin coating method, and an electron acceleration layer 4 was obtained. The film thickness of the electron acceleration layer 4 was about 1.7 μm.

An electron-emitting device of Example 5 was obtained by forming a thin film electrode 3 on the surface of the electron acceleration layer 4 using a magnetron sputtering apparatus. Gold was used as a film forming material for the thin film electrode 3, the layer thickness of the thin film electrode was 40 nm, and the area was 0.014 cm ² .

When the experimental system of FIG. 3 using this electron-emitting device was applied in a vacuum of 1 × 10 ⁻⁸ ATM, the applied voltage V1 = 18.5V to the thin film electrode and the applied voltage V2 = 100V to the counter electrode, An electron emission current of 1.17 mA / cm ² per unit area was confirmed.

  Here, the electron-emitting devices of Examples 1 to 4 described above include the binder resin in which the insulator material and the conductive fine particles are dispersed in the electron acceleration layer 4, but only the insulator material, which is a modified example thereof, is included. Electron emission was also confirmed for the electron acceleration layer 4 ′ containing the dispersed binder resin. Therefore, this modification will be described below.

(Modification)
Electron acceleration was performed by dropping the dispersion A obtained in the same manner as in Example 1 onto a 30 mm square SUS substrate as the electrode substrate 2 and then depositing an insulator substance-containing resin binder at 3000 rpm for 10 s using a spin coating method. Layer 4 ′ was obtained. The film thickness of the electron acceleration layer 4 ′ was about 1.5 nm.

A thin film electrode 3 was formed on the surface of the electron acceleration layer 4 ′ by using a magnetron sputtering apparatus to obtain a modified electron-emitting device. Gold was used as a film forming material for the thin film electrode 3, the layer thickness of the thin film electrode 3 was 40 nm, and the area was 0.014 cm ² .

The experimental system shown in FIG. 3 using the electron-emitting device of this modification is as follows: in a vacuum of 1 × 10 ⁻⁸ ATM, the applied voltage V1 = 17.2V to the thin film electrode and the applied voltage V2 = 100V to the counter electrode. As a result, the electron emission current per unit area was confirmed to be 0.05 mA / cm ² .

[Embodiment 2]
FIG. 4 shows an example of a charging device 90 according to the present invention using the electron-emitting device 1 according to the present invention described in the first embodiment. The charging device 90 includes the electron-emitting device 1 and a power source 7 that applies a voltage to the electron-emitting device 1, and charges the photoconductor 11. The image forming apparatus according to the present invention includes the charging device 90. In the image forming apparatus according to the present invention, the electron-emitting device 1 constituting the charging device 90 is installed facing the photosensitive member 11 that is a member to be charged, and emits electrons by applying a voltage to the photosensitive member 11. Is charged. In the image forming apparatus according to the present invention, conventionally known members may be used other than the charging device 90. Here, it is preferable that the electron-emitting device 1 used as the charging device 90 is disposed 3 to 5 mm away from the photoreceptor 11, for example. The applied voltage to the electron-emitting device 1 is preferably about 25V, and the electron acceleration layer of the electron-emitting device 1 is configured such that, for example, 1 μA / cm ² of electrons is emitted per unit time when a voltage of 25V is applied. It only has to be.

  The electron-emitting device 1 used as the charging device 90 does not discharge even when operated in the atmosphere, and therefore no ozone is generated from the charging device 90. Ozone is harmful to the human body and regulated by various environmental standards, and even if it is not released outside the machine, it oxidizes and degrades organic materials such as the photoreceptor 11 and the belt. Such a problem can be solved by using the electron-emitting device 1 according to the present invention for the charging device 90 and having the charging device 90 in the image forming apparatus.

  Further, since the electron-emitting device 1 used as the charging device 90 is configured as a surface electron source, it can be charged with a width in the rotation direction of the photoconductor 11 and there are many opportunities for charging to a certain place of the photoconductor 11. You can earn. Therefore, the charging device 90 can be uniformly charged as compared with a wire charger that charges in a linear manner. Further, the charging device 90 has an advantage that the applied voltage can be remarkably reduced to about 10 V as compared with a corona discharger that requires voltage application of several kV.

[Embodiment 3]
FIG. 5 shows an example of an electron beam curing apparatus 100 according to the present invention using the electron-emitting device 1 according to the present invention described in the first embodiment. The electron beam curing apparatus 100 includes an electron-emitting device 1, a power source 7 that applies a voltage to the electron-emitting device 1, and an acceleration electrode 21 that accelerates electrons. In the electron beam curing apparatus 100, the electron-emitting device 1 is used as an electron source, and the emitted electrons are accelerated by the acceleration electrode 21 and collide with the resist 22. Since the energy required for curing the general resist 22 is 10 eV or less, the acceleration electrode is not necessary if attention is paid only to the energy. However, since the penetration depth of the electron beam is a function of electron energy, for example, an acceleration voltage of about 5 kV is required to cure all the resist 22 having a thickness of 1 μm.

  A conventional general electron beam curing apparatus seals an electron source in a vacuum, emits electrons by applying a high voltage (50 to 100 kV), takes out electrons through an electron window, and irradiates them. With this electron emission method, a large energy loss occurs when transmitting through the electron window. Further, since electrons reaching the resist also have high energy, they pass through the thickness of the resist, resulting in low energy utilization efficiency. Further, since the range that can be irradiated at one time is narrow and drawing is performed in a dot shape, the throughput is also low.

  On the other hand, since the electron beam curing apparatus according to the present invention using the electron-emitting device 1 can operate in the atmosphere, there is no need for vacuum sealing. Further, since the electron transmission window is not passed, there is no energy loss and the applied voltage can be lowered. Further, since it is a surface electron source, the throughput is remarkably increased. Further, if electrons are emitted according to the pattern, maskless exposure can be performed.

[Embodiment 4]
FIGS. 6 to 8 show examples of the self-luminous device according to the present invention using the electron-emitting device 1 according to the present invention described in the first embodiment.

  A self-luminous device 31 shown in FIG. 6 includes an electron-emitting device 1, a power source 7 that applies a voltage to the electron-emitting device 1, and a glass substrate 34 and an ITO film 33 that are base materials at positions facing and away from the electron-emitting device 1. The phosphor 32 includes a light emitting unit 36 having a laminated structure.

As the phosphor 32, an electron excitation type material corresponding to red, green, and blue light emission is suitable, for example, Y ₂ O ₃ : Eu for red, (Y, Gd) BO ₃ : Eu, and Zn ₂ SiO for green. ₄ : Mn, BaAl ₁₂ O ₁₉ : Mn, blue, BaMgAl ₁₀ O ₁₇ : Eu ^{2+ and the} like can be used. A phosphor 32 is formed on the surface of the glass substrate 34 on which the ITO film 33 is formed. The thickness of the phosphor 32 is preferably about 1 μm. In addition, the thickness of the ITO film 33 is 150 nm in the present embodiment, as long as the film thickness can ensure conductivity.

  In forming the phosphor 32, it is preferable to prepare a kneaded product of an epoxy resin serving as a binder and finely divided phosphor particles and form the film by a known method such as a bar coater method or a dropping method.

  Here, in order to increase the light emission luminance of the phosphor 32, it is necessary to accelerate the electrons emitted from the electron-emitting device 1 toward the phosphor. In this case, the electrode substrate 2 and the light-emitting portion 36 of the electron-emitting device 1 are used. In order to apply a voltage for forming an electric field for accelerating electrons between the ITO films 33, a power source 35 is preferably provided. At this time, the distance between the phosphor 32 and the electron-emitting device 1 is preferably 0.3 to 1 mm, the applied voltage from the power source 7 is preferably 18 V, and the applied voltage from the power source 35 is preferably 500 to 2000 V.

  A self-luminous device 31 ′ shown in FIG. 7 includes an electron-emitting device 1, a power source 7 that applies a voltage to the electron-emitting device 1, and a phosphor 32. In the self-luminous device 31 ′, the phosphor 32 has a planar shape, and the phosphor 32 is disposed on the surface of the electron-emitting device 1. Here, the phosphor 32 layer formed on the surface of the electron-emitting device 1 is prepared as a coating liquid composed of a kneaded material with the phosphor particles finely divided as described above, and is formed on the surface of the electron-emitting device 1. To do. However, since the electron-emitting device 1 itself has a structure that is weak against external force, there is a risk that the device may be damaged if film forming means by the bar coater method is used. Therefore, a method such as a dropping method or a spin coating method may be used.

  A self-luminous device 31 ″ shown in FIG. 8 includes an electron-emitting device 1 and a power source 7 that applies a voltage to the electron-emitting device 1, and further, fluorescent fine particles as phosphors 32 ′ are formed on the electron acceleration layer 4 of the electron-emitting device 1. In this case, the fine particles of the phosphor 32 ′ may be used also as the insulator fine particles 5. However, the above-described phosphor fine particles generally have a low electric resistance, and are clear as compared with the insulator fine particles 5. Therefore, when the phosphor fine particles are mixed with the insulator fine particles 5 and mixed, the amount of the phosphor fine particles must be suppressed to a small amount, for example, as the insulator fine particles 5 as spherical silica particles. When ZnS: Mg (average diameter: 500 nm) is used as the phosphor fine particles (average diameter: 110 nm), a weight mixing ratio of about 3: 1 is appropriate.

  In the self-light-emitting devices 31, 31 ', 31 ", the electrons emitted from the electron-emitting device 1 collide with the phosphors 32, 32 to emit light. The self-light-emitting devices 31, 31', 31" Since the emission element 1 can emit electrons in the atmosphere, it can be operated in the atmosphere. However, if it is vacuum-sealed, the electron emission current is increased and light can be emitted more efficiently.

Furthermore, FIG. 9 shows an example of an image display device according to the present invention provided with the self-luminous device according to the present invention. An image display device 140 shown in FIG. 9 includes the self-light emitting device 31 ″ shown in FIG. 8 and a liquid crystal panel 330. In the image display device 140, the self-light emitting device 31 ″ is installed behind the liquid crystal panel 330. And used as a backlight. When used in the image display device 140, the applied voltage to the self-luminous device 31 ″ is preferably 20 to 35 V, and for example, 10 μA / cm ² of electrons are emitted per unit time at this voltage. The distance between the self-light emitting device 31 ″ and the liquid crystal panel 330 is preferably about 0.1 mm.

Further, when the self-luminous device 31 shown in FIG. 6 is used as the image display device according to the present invention, the self-luminous devices 31 are arranged in a matrix, and an image is formed and displayed as an FED by the self-luminous device 31 itself. It can also be a shape. In this case, the applied voltage to the self-luminous device 31 is preferably 20 to 35 V, and it is sufficient that, for example, 10 μA / cm ² of electrons are emitted per unit time at this voltage.

[Embodiment 5]
10 and 11 show examples of the blower according to the present invention using the electron-emitting device 1 according to the present invention described in the first embodiment. Below, the case where the air blower concerning this invention is used as a cooling device is demonstrated. However, the use of the blower is not limited to the cooling device.

A blower 150 shown in FIG. 10 includes an electron-emitting device 1 and a power source 7 that applies a voltage to the electron-emitting device 1. In the blower 150, the electron-emitting device 1 emits electrons toward the object 41 to be cooled, which is electrically grounded, thereby generating ion wind to cool the object 41 to be cooled. In the case of cooling, the voltage applied to the electron-emitting device 1 is preferably about 18 V, and it is preferable to emit, for example, 1 μA / cm ² of electrons per unit time at this voltage in the atmosphere.

The blower 160 shown in FIG. 11 is further combined with the blower 150 shown in FIG. The blower 160 shown in FIG. 11 emits electrons toward the cooled object 41 in which the electron-emitting device 1 is electrically grounded, and the blower fan 42 blows air toward the cooled object 41 to generate electrons. Electrons emitted from the emitting element are sent toward the cooled object 41 to generate an ion wind to cool the cooled object 41. In this case, the air volume by the blower fan 42 is preferably 0.9 to ² L / min / cm ² .

  Here, when the object to be cooled 41 is cooled by air blowing, the flow velocity on the surface of the object to be cooled 41 becomes 0 only by air blowing by a fan or the like as in the conventional air blowing device or cooling device, and the most heat is released. The air in the desired part is not replaced and the cooling efficiency is poor. However, when charged particles such as electrons and ions are contained in the air to be blown, when the vicinity of the object to be cooled 41 is approached, it is attracted to the surface of the object to be cooled 41 by electric force. The atmosphere can be changed. Here, in the air blowers 150 and 160 according to the present invention, since the air to be blown contains charged particles such as electrons and ions, the cooling efficiency is remarkably increased. The blower 150 and the blower 106 can also be operated in the atmosphere.

  The present invention is not limited to the above-described embodiments and examples, and various modifications are possible within the scope of 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.

  The electron-emitting device according to the present invention can ensure electrical continuity, flow a sufficient current in the device, and emit ballistic electrons from the thin film electrode. Therefore, for example, an image display device by combining with an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile, an electron beam curing device, or a light emitter, or an ion wind generated by emitted electrons. Can be suitably applied to a cooling device or the like.

DESCRIPTION OF SYMBOLS 1 Electron emission element 2 Electrode substrate 3 Thin film electrode 4 Electron acceleration layer 5 Insulator fine particle (insulator substance)
6 Conductive fine particles 7 Power supply (Power supply part)
8 Counter electrode 9 Insulator spacer 10 Electron emitter 11 Photoreceptor 15 Binder resin 21 Accelerating electrode 22 Resist 31, 31 ′, 31 ″ Self-emitting device 32, 32 ′ Phosphor 33 ITO film 34 Glass substrate 35 Power supply 36 Light emitting part 41 Cooled object 42 Blower fan 90 Charging device 100 Electron beam curing device 140 Image display device 150 Blower device 160 Blower device 330 Liquid crystal panel

Claims (24)

An electrode substrate, a thin film electrode, and an electrode acceleration layer sandwiched between the electrode substrate and the thin film electrode. When a voltage is applied between the electrode substrate and the thin film electrode, electrons are transmitted through the electron acceleration layer. An electron-emitting device that accelerates and emits the electrons from the thin film electrode,
The electron-emitting device, wherein the electron acceleration layer includes a resin binder in which an insulating material and conductive fine particles are dispersed.   The electron-emitting device according to claim 1, wherein the conductive fine particles are a conductor having high anti-oxidation power.   The electron-emitting device according to claim 1, wherein the conductive fine particles are a noble metal.   The electron-emitting device according to any one of claims 1 to 3, wherein the conductive material forming the conductive fine particles contains at least one of gold, silver, platinum, palladium, and nickel.   5. The electron-emitting device according to claim 1, wherein the conductive fine particles have an average diameter of 3 to 10 nm. The insulator _{material, SiO 2, Al 2 O 3} , and characterized in that it includes the TiO ₂ comprises at least one, or an organic polymer, in any one of claims 1 5 The electron-emitting device described.   The electron-emitting device according to any one of claims 1 to 6, wherein the insulator substance is fine particles, and an average diameter thereof is 10 to 1000 nm.   The electron-emitting device according to claim 7, wherein the average diameter is 12 to 110 nm.   9. The electron-emitting device according to claim 1, wherein a ratio of the conductive fine particles in the electron acceleration layer is 0.5 to 30% by weight.   10. The electron-emitting device according to claim 9, wherein a ratio of the conductive fine particles in the electron acceleration layer is 1 to 10% by weight.   The electron-emitting device according to any one of claims 1 to 10, wherein the electron acceleration layer has a thickness of 12 to 6000 nm.   The electron-emitting device according to claim 11, wherein the electron acceleration layer has a thickness of 300 to 6000 nm.   The electron-emitting device according to any one of claims 1 to 12, wherein the thin-film electrode includes at least one of gold, silver, carbon, tungsten, titanium, aluminum, and palladium.   14. The electron-emitting device according to claim 1, wherein a small insulator material, which is an insulator material smaller than the size of the conductive fine particles, is present around the conductive fine particles.   The electron-emitting device according to claim 14, wherein the small insulator material includes at least one of alcoholate, fatty acid, and alkanethiol.   An electron-emitting device comprising: the electron-emitting device according to claim 1; and a power supply unit that applies a voltage between the electrode substrate and the thin-film electrode.   A self-luminous device comprising the electron-emitting device according to claim 16 and a light emitter, wherein the light-emitting device emits electrons by emitting electrons from the electron-emitting device.   An image display device comprising the self-luminous device according to claim 17.   An air blower comprising the electron emission device according to claim 16, wherein electrons are emitted from the electron emission device to blow air.   A cooling device comprising the electron-emitting device according to claim 16, wherein the object to be cooled is cooled by emitting electrons from the electron-emitting device.   A charging device comprising the electron-emitting device according to claim 16, wherein the photosensitive member is charged by emitting electrons from the electron-emitting device.   An image forming apparatus comprising the charging device according to claim 21.   An electron beam curing device comprising the electron emission device according to claim 16. An electrode substrate, a thin film electrode, and an electrode acceleration layer sandwiched between the electrode substrate and the thin film electrode. When a voltage is applied between the electrode substrate and the thin film electrode, electrons are transmitted through the electron acceleration layer. A method of manufacturing an electron-emitting device that accelerates and emits the electrons from the thin-film electrode,
A dispersion adjusting step of adjusting a dispersion in which an insulator substance is dispersed in a resin binder;
A mixed solution adjusting step of adjusting a mixed solution in which conductive fine particles are dispersed in the dispersion;
An electron acceleration layer forming step of forming the electron acceleration layer by applying the mixed solution on the electrode substrate;
A method for manufacturing an electron-emitting device, comprising:

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