JP2010267492A - Method for manufacturing electron emitting element, electron emitting element, electron emitting device, charging device, image forming device, electron beam curing device, self-luminous device, image display, blower, and cooling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an electron emitting element for making a small amount of conductive particulates exist uniformly simply and at a low cost, and for making stable and excellent electron emission. <P>SOLUTION: The forming process of an electron acceleration layer 4 of the electron emitting element 1 includes a particulate layer forming process in which a particulate layer containing insulator particulates 5 is formed by coating a dispersion liquid in which the insulator particulates 5 are dispersed, and a conductive particulate coating process in which a dispersion liquid of conductive particulates 6 is coated on the particulate layer by an electrostatic spray method. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an electron-emitting device that emits electrons by applying a voltage, an electron-emitting device, and the like.

  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.

  On the other hand, MIM (Metal Insulator Metal) 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.

  For example, Patent Document 1 discloses an MIM type electron-emitting device having an insulator film in which fine particles are dispersed as an electron acceleration layer between two opposing electrodes. In Patent Document 1, when fine particles are dispersed in an insulator film, a voltage of 10 V or more can be applied to the electron-emitting device, and the dielectric breakdown of the insulator film hardly occurs, and the yield and reproducibility are improved. It has been reported.

JP-A-1-298623 (published on December 1, 1991)

However, in the electron-emitting device of Patent Document 1, fine particles are dispersed in an insulator coating liquid, and the insulator film is formed by baking after being applied on the electrode substrate. Is required. The fine particles dispersed in the insulator film are those having an average particle size of 1000 × 10 ⁻¹⁰ m or less. The fine particles have different melting points depending on the material forming the fine particles, but the smaller the particle diameter, the faster the melting. For this reason, in the electron-emitting device disclosed in Patent Document 1, fine particles are melted earlier than the formation of the insulator film in the firing step, causing aggregation and segregation, and the expected effect may not be expected. .

  In addition, in the electron-emitting device of Patent Document 1, an insulating coating liquid in which conductive fine particles are dispersed is applied. When this application is performed by spin coating or dipping, the location and amount of the electron-emitting portion are controlled. It is difficult to form a thin film.

  For this reason, it is necessary to eliminate the firing step and make the fine particles exist in a small amount and uniformly in the electron-emitting device.

  In addition, forming a plurality of electron-emitting devices on a common substrate has been performed so far, but the conventional method has a problem that a plurality of electron-emitting devices can be formed only on a flat substrate. I had it. In addition, controlling the position of an electron emission portion, which is a location where electrons are emitted from an electron-emitting device, has been conventionally performed, and a vacuum deposition method or the like is known. However, the vacuum deposition method has a problem that a large-scale apparatus such as a vacuum facility is required and the manufacturing cost is increased.

  The present invention has been made in view of the above problems, and a method for producing an electron-emitting device capable of uniformly presenting a small amount of conductive fine particles at a simple and low cost and capable of emitting stable and good electrons, and An object is to provide an electron-emitting device or the like. Another object is to collectively form a plurality of electron-emitting devices. Furthermore, it aims at providing the electron emission element which can control the position of an electron emission part.

  In order to solve the above problems, an electron-emitting device manufacturing method according to the present invention includes an electrode substrate, a thin film electrode, an electron acceleration layer including conductive fine particles and insulating fine particles sandwiched between the electrode substrate and the thin film electrode, When the voltage is applied between the electrode substrate and the thin film electrode, the electron acceleration layer accelerates the electrons and emits the electrons from the thin film electrode. The step of forming the electron acceleration layer includes the step of applying an insulating fine particle dispersion in which the insulating fine particles are dispersed in a dispersion solvent to form a fine particle layer containing the insulating fine particles on the electrode substrate. The method includes a forming step and a conductive fine particle coating step in which the conductive fine particle dispersion in which the conductive fine particles are dispersed in a dispersion solvent is applied to the fine particle layer using an electrostatic spraying method.

  Here, the electron emission amount of the electron-emitting device does not increase in proportion to the amount of conductive fine particles in the electron acceleration layer, but rather the electrons are emitted as ballistic electrons in the electron acceleration layer. It only needs to be semiconductive. Therefore, the amount of conductive fine particles required in the electron acceleration layer may be small. On the other hand, in order to obtain a device with uniform performance, the electron emission portion, which is a region where conductive fine particles are introduced, must not be unevenly distributed. Therefore, for device production, a dispersion medium with good dispersibility is selected for each fine particle, and a small amount of conductive fine particle dispersion is uniformly applied on the fine particle layer containing the insulating fine particles, and the upper part or the inside of the fine particle layer, or It is required that the conductive fine particles exist uniformly in the upper and inner regions where the conductive fine particles are introduced.

  According to the above method, in the step of forming the electron acceleration layer, a fine particle layer containing insulating fine particles is formed, and a conductive fine particle dispersion is applied onto the fine particle layer using an electrostatic spray method. By this method, the conductive fine particles can be present in a small amount and uniformly in the upper part or inside of the fine particle layer, or in the upper and inner regions where the conductive fine particles are introduced. Therefore, it is possible to manufacture an electron-emitting device that has an electron-emitting portion uniformly and can stably and satisfactorily emit electrons. In addition, by applying a voltage to the electrode substrate and the spray needle after the formation of the fine particle layer and electrostatically spraying the conductive fine particle dispersion solution, the conductive fine particles reach the fine particle layer without diffusing, and wasteful conductive fine particles are consumed. Can be suppressed. In addition, since the electrostatic spraying method is used, the conductive fine particles can be uniformly introduced regardless of the shape of the fine particle layer, and the electron emission portion, which is the region where the conductive fine particles are introduced, can be formed on the curved surface. The shape of the emitting element can be manufactured without limitation.

  Furthermore, according to the above method, since the insulating fine particle dispersion solution and the conductive fine particle dispersion solution are prepared separately and applied onto the electrode substrate, aggregates are generated when the insulating fine particle dispersion solution and the conductive fine particle dispersion solution are mixed. It is possible to prevent problems such as

  Therefore, after applying the insulating fine particle dispersion on the electrode substrate to form a fine particle layer containing the insulating fine particles, the conductive fine particle dispersion is applied, so that there are few aggregates of fine particles and the fine particles are uniformly dispersed. An electron acceleration layer can be formed. In addition, an electron-emitting device can be obtained easily and at low cost by a simple manufacturing process of applying a fine particle dispersion.

  As described above, according to the method of the present invention, it is possible to avoid the generation of aggregates of fine particles, and conductive fine particles are introduced into the upper part or the inner part of the fine particle layer including the uniformly dispersed insulating fine particles, or the upper part and the inner part. An electron acceleration layer in which electron emission portions are uniformly present in the region can be formed easily and at low cost, and an electron-emitting device that emits electrons stably and satisfactorily can be manufactured.

  In the method for manufacturing an electron-emitting device of the present invention, in addition to the above method, the insulating fine particle dispersion and the conductive fine particle dispersion may contain different dispersion solvents.

  Here, the following problems occur when the insulating fine particles and the conductive fine particles have different dispersion solvents that are easy to disperse. In the case where the insulating fine particle dispersion and the conductive fine particle dispersion contain different dispersion solvents, agglomerates are likely to occur when both fine particles are mixed. Therefore, in order to prevent the formation of aggregates when both fine particles are mixed, if one of the insulating fine particles and the conductive fine particles is aligned with a dispersion solvent having good dispersibility, the dispersibility of the other fine particles is reduced and aggregates are formed. appear. Therefore, it does not solve the generation of aggregates after all.

  However, according to the above method according to the present invention, the insulating fine particle dispersion is applied by coating the insulating fine particle dispersion without mixing both, even if the insulating fine particles and the conductive fine particles are different in dispersion solvent. After forming the fine particle layer, the electron acceleration layer can be formed while maintaining the dispersibility of both fine particles by applying the conductive fine particle dispersion. That is, even if the insulating fine particles and the conductive fine particles have different dispersion solvents with high dispersibility, the insulating fine particles aggregates, the conductive fine particle aggregates, and the uniform electrons not including the insulating fine particle and conductive fine particle aggregates An acceleration layer can be formed.

  In the method for manufacturing an electron-emitting device of the present invention, in addition to the above method, the insulating fine particle dispersion may contain a binder component.

  In the fine particle layer containing the binder component and the insulating fine particles, the dispersed state of the insulating fine particles is maintained. Therefore, even if the conductive fine particle dispersion is applied by electrostatic spraying, the insulating fine particles in the fine particle layer The distributed state does not change. Therefore, an electron acceleration layer in which the electron emission portion is uniformly controlled can be formed, and an electron-emitting device capable of stable and good electron emission can be manufactured. Furthermore, the binder component has high adhesiveness with the electrode substrate, and can increase the mechanical strength of the element.

  In the method for manufacturing an electron-emitting device of the present invention, in addition to the above method, the conductive fine particle dispersion may be a nanocolloid liquid of the conductive fine particles.

  According to the above method, the nano colloid liquid of conductive fine particles is applied to the fine particle layer containing the insulating fine particles. Here, since the nanocolloid liquid is used in a liquid state, it is possible to apply a dispersion in which the conductive fine particles are uniformly dispersed without aggregation. Therefore, an electron accelerating layer in which conductive fine particles are present more uniformly is formed on the fine particle layer, and an electron-emitting device capable of stable and good electron emission can be manufactured.

  In addition to the above method, in the method for manufacturing an electron-emitting device of the present invention, in the conductive fine particle application step, a mask is placed on the fine particle layer, and the conductive fine particle dispersion is applied using an electrostatic spraying method. May be.

  According to the above method, when the mask is installed, the conductive fine particle dispersion is applied using the electrostatic spraying method, and then the mask is removed. The conductive fine particles are not so dispersed in the place. Therefore, the dispersion liquid of conductive fine particles can be applied to any location in the fine particle layer. Here, the mask to be used may be a metal mask or another mask, and is not particularly limited. Therefore, by controlling the size of the mask and the size of the unmasked area, the arrangement of the electron acceleration layer on the common electrode substrate can be patterned, or conductive fine particles are introduced for each element. The electron emission portion can be patterned. In addition, by forming the thin film electrodes on the electron acceleration layer patterned on the common electrode substrate so as to be insulated from each other, each becomes an electron-emitting device. Therefore, a plurality of electron-emitting devices are formed on the common electrode substrate. Can be created at once. Further, since the electrostatic spraying method is used, the conductive fine particles are uniformly dispersed in the region where the conductive fine particles are introduced.

  In order to solve the above-mentioned problems, an electron-emitting device according to the present invention is manufactured by any one of the above-described methods for manufacturing an electron-emitting device.

  In the electron-emitting device manufactured by the method according to the present invention, the electron acceleration layer between the electrode substrate and the thin film electrode is a layer containing insulating fine particles and conductive fine particles, 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. This electron-emitting device is manufactured easily and at low cost, and a small amount of conductive fine particles are present uniformly in the electron-emitting portion. Therefore, electrons can be emitted with a stable and good electron emission amount. Moreover, since the electron emission part which is an area | region where the conductive fine particle was introduce | transduced in the element is formed by an electrostatic spraying method, this electron emission part is obtained also on a curved surface, and the shape of an electron emission element is not limited. Therefore, the electron-emitting device of the present invention can be installed in devices having various shapes, and the range of devices that can be applied is wide.

  The electron-emitting device according to the present invention includes an electrode substrate, a thin film electrode, the electrode substrate and an electron acceleration layer sandwiched between the electrode substrate, and a voltage is applied between the electrode substrate and the thin film electrode. And an electron-emitting device for accelerating electrons in the electron acceleration layer and emitting the electrons from the thin film electrode, wherein the electron acceleration layer is composed of a fine particle layer containing insulating fine particles, and at least the Conductive fine particles are discretely arranged on the surface of the fine particle layer.

  According to the above configuration, since the conductive fine particles are discretely arranged on the surface of the fine particle layer composed of at least the insulating fine particles, the arrangement location becomes the electron emission portion. Therefore, the electron-emitting device is an electron-emitting device in which the electron-emitting portion is patterned. Therefore, the position of the electron emission portion can be controlled, and the phenomenon that the constituent material of the thin film electrode formed on the electron acceleration layer disappears due to the emitted electrons can be prevented. Moreover, the amount of electron emission from each electron emission part can be controlled independently.

  The electron-emitting device according to the present invention includes an electrode substrate, a thin film electrode, the electrode substrate and an electron acceleration layer sandwiched between the electrode substrate, and a voltage is applied between the electrode substrate and the thin film electrode. And an electron-emitting device for accelerating electrons in the electron acceleration layer and emitting the electrons from the thin film electrode, wherein the electron acceleration layer includes insulator fine particles and conductive fine particles, and A plurality of electrode substrates are formed on a flat or curved electrode substrate.

  According to the above configuration, a plurality of electron-emitting devices can be formed on a common electrode substrate, and can be suitably used in an apparatus that requires a plurality of electron-emitting devices.

  In the electron-emitting device of the present invention, the conductive fine particles preferably have an average particle size of 3 to 10 nm. By setting the average particle diameter of the conductive fine particles to 3 to 10 nm, a conductive path due to the conductive fine particles is not formed in the electron acceleration layer, and dielectric breakdown does not easily occur in the electron acceleration layer. Although there are many unclear points in principle, ballistic electrons are efficiently generated by using conductive fine particles having an average particle diameter within the above range.

  In the electron-emitting device of the present invention, in addition to the above configuration, the average particle size of the insulating fine particles is preferably 10 to 500 nm, which is larger than the average particle size of the conductive fine particles. 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. Since the average particle size of the insulating fine particles is larger than the average particle size of the conductive fine particles, heat can be efficiently conducted from the inside to the outside of the conductive fine particles smaller than the average particle size of the insulating fine particles, and the current inside the device Joule heat generated when flowing 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.

  Here, the degree of penetration of the conductive fine particles into the fine particle layer containing the insulating fine particles depends on the type and / or average particle size of the insulating fine particles, the type and / or average particle size of the conductive fine particles, and the combination of the insulating fine particles and the conductive fine particles. Depends on etc. That is, when the average particle diameter of the insulating fine particles is small, most of the applied conductive fine particles do not penetrate into the fine particle layer but deposit on the upper part. On the other hand, if the average particle size of the insulating fine particles is large, the gaps between the particles of the fine particle layer become too large, and the conductive fine particles staying in the fine particle layer are reduced. Therefore, when using conductive fine particles having an average particle diameter of 3 to 10 nm, the average particle diameter of the insulating fine particles is preferably 10 to 500 nm in order to control the degree of penetration of the conductive fine particles into the fine particle layer.

  When the binder component is included in the electron acceleration layer, if the average particle size of the insulating fine particles is larger than 200 nm, most of the applied conductive fine particles having an average particle size of 3 to 10 nm include the insulating fine particles. Does not stay on top of the binder component layer. Therefore, when the electron acceleration layer contains a binder component and conductive fine particles having an average particle diameter of 3 to 10 nm are used, the average particle diameter of the insulating fine particles is preferably 10 to 200 nm.

  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 means that the oxide forming 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 covering an insulating material smaller than the average particle diameter of the conductive fine particles around the corresponding conductive fine particles are also anti-oxidant. Included in conductive particles with high strength.

  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 configuration, the insulating fine particles may include at least one of SiO ₂ , Al ₂ O ₃ , and TiO ₂ . Or it may contain an organic polymer. If the insulating fine particles contain at least one of SiO ₂ , Al ₂ O ₃ , and TiO ₂ , or contain an organic polymer, the insulating properties of these substances are high, so that the electron acceleration layer 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 the insulating fine particles and a conductive material having high anti-oxidation power is used as the conductive fine particles, 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.

  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, 1 to 10% 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, a small insulator material that is an insulator material smaller than the size of the conductive fine particles may exist around the conductive fine particles. As described above, the presence of a small insulating material smaller than the size of the conductive fine particles around the conductive fine particles contributes to the improvement of the dispersibility of the conductive fine particles in the dispersion liquid at the time of device fabrication. It is possible to more effectively prevent device deterioration such as oxidation of fine particles by 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 small insulator material may contain at least one of alcoholate, fatty acid, and alkanethiol. As described above, since the small insulator material contains at least one of alcoholate, fatty acid, and alkanethiol, it contributes to improvement in dispersibility of the conductive fine particles in the dispersion liquid at the time of device creation. In addition to making it difficult to form abnormal current paths due to the aggregate of fine particles, it does not cause changes in the composition of the particles due to oxidation of the conductive fine particles themselves around the insulating fine particles, thus affecting the electron emission characteristics. There is nothing. Therefore, the lifetime of the electron-emitting device can be extended more effectively.

  Here, in the electron-emitting device of the present invention, the small insulator substance is attached to the surface of the conductive fine particles and exists as an attached substance, and the attached substance is smaller than the average particle diameter of the conductive fine particles. The conductive fine particle surface may be coated as an aggregate of shapes. In this way, the small insulating material adheres to the surface of the conductive fine particles or coats the surface of the conductive fine particles as an aggregate having a shape smaller than the average particle diameter of the conductive fine particles, so that the element can be formed. In order to contribute to improving the dispersibility of the conductive fine particles in the dispersion liquid, the aggregate of the conductive fine particles makes it difficult to form an abnormal current path based on the current, and also oxidizes the conductive fine particles themselves existing around the insulating fine particles. As a result, no change in the composition of the particles is caused, so that 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 said structure, it can manufacture simply and at low cost, and can discharge | emit stable and favorable electron.

  Further, by using the electron emission device of the present invention in a charging device and an image forming apparatus equipped with this charging device, electrons can be stably and satisfactorily emitted, so that stable and favorable charging can be achieved. Furthermore, the object to be charged can be stably charged for a long period of time without generating harmful substances such as ozone and NOx without discharging.

  Further, by using the electron emission device of the present invention in an electron beam curing device, it is possible to emit electrons stably and satisfactorily, so that an electron beam can be irradiated with high stability and goodness. In addition, the electron beam can be cured in terms of area, masklessness can be achieved, and low cost and high throughput can be realized.

  Further, by using the electron emitting device of the present invention for a self-luminous device and an image display device equipped with the self-luminous device, electrons can be emitted stably and satisfactorily, and light can be emitted with high efficiency. In addition, it is possible to provide a self-luminous device that realizes stable and good surface light emission.

  Further, by using the electron emission device of the present invention for a blower device or a cooling device, electrons can be emitted stably and satisfactorily, so that it can be cooled stably and satisfactorily. Further, no harmful substances such as ozone and NOx are generated without discharge, and cooling can be efficiently performed by utilizing the slip effect on the surface of the object to be cooled.

  In the method for manufacturing an electron-emitting device according to the present invention, as described above, in the step of forming the electron acceleration layer, an insulator fine particle dispersion in which the insulator fine particles are dispersed in a dispersion solvent is applied onto the electrode substrate. A fine particle layer forming step for forming a fine particle layer containing insulating fine particles, and a conductive fine particle application in which a conductive fine particle dispersion in which the conductive fine particles are dispersed in a dispersion solvent is applied to the fine particle layer by using an electrostatic spray method Process.

  According to the above method, in the step of forming the electron acceleration layer, a fine particle layer containing insulating fine particles is formed, and a conductive fine particle dispersion is applied onto the fine particle layer using an electrostatic spray method. By this method, the conductive fine particles can be present in a small amount and uniformly in the upper part or inside of the fine particle layer, or in the upper and inner regions where the conductive fine particles are introduced. Therefore, it is possible to manufacture an electron-emitting device that has an electron-emitting portion uniformly and can stably and satisfactorily emit electrons. In addition, by applying a voltage to the electrode substrate and the spray needle after the formation of the fine particle layer and electrostatically spraying the conductive fine particle dispersion solution, the conductive fine particles reach the fine particle layer without diffusing, and wasteful conductive fine particles are consumed. Can be suppressed. In addition, since the electrostatic spraying method is used, the conductive fine particles can be uniformly introduced regardless of the shape of the fine particle layer, and the electron emission portion, which is the region where the conductive fine particles are introduced, can be formed on the curved surface. The shape of the emitting element can be manufactured without limitation.

  Furthermore, according to the above method, since the insulating fine particle dispersion solution and the conductive fine particle dispersion solution are prepared separately and applied onto the electrode substrate, aggregates are generated when the insulating fine particle dispersion solution and the conductive fine particle dispersion solution are mixed. It is possible to prevent problems such as

  Therefore, after applying the insulating fine particle dispersion on the electrode substrate to form a fine particle layer containing the insulating fine particles, the conductive fine particle dispersion is applied, so that there are few aggregates of fine particles and the fine particles are uniformly dispersed. An electron acceleration layer can be formed. In addition, an electron-emitting device can be obtained easily and at low cost by a simple manufacturing process of applying a fine particle dispersion.

  As described above, according to the method of the present invention, it is possible to avoid the generation of aggregates of fine particles, and conductive fine particles are introduced into the upper part or the inner part of the fine particle layer including the uniformly dispersed insulating fine particles, or the upper part and the inner part. An electron acceleration layer in which electron emission portions are uniformly present in the region can be formed easily and at low cost, and an electron-emitting device that emits electrons stably and satisfactorily can be manufactured.

It is a schematic diagram which shows the structure of the electron emission apparatus which has the electron emission element of this invention. It is a figure explaining charging a photoreceptor using an electron emission device having a plurality of electron emission portions as a charging device. 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 emission apparatus of this invention. It is a figure which shows an example of the electron beam hardening apparatus using the electron emission apparatus of this invention. It is a figure which shows an example of the self-light-emitting device using the electron emission apparatus of this invention. It is a figure which shows another example of the self-light-emitting device using the electron emission apparatus of this invention. It is a figure which shows another example of the self-light-emitting device using the electron emission apparatus 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 emission apparatus of this invention. It is a figure which shows an example of the air blower using the electron emission apparatus of 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 apparatus of this invention, and a cooling device provided with the same.

  Hereinafter, embodiments and examples of an electron-emitting device and a method for manufacturing the same according to 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 manufactured by the manufacturing method of the present invention. As shown in the figure, the electron-emitting device 1 of the present embodiment includes an electrode substrate 2 serving as a lower electrode, a thin film electrode 3 serving as 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 insulator substrate such as a glass substrate is used, it can be used as the electrode substrate 2 to be the lower electrode by attaching a conductive material such as a metal as an electrode to the interface with the electron acceleration layer 4. . 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. However, if a stable operation in the air is desired, it is preferable to use a conductor with high antioxidation power, 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 100 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 100 nm. If the film thickness exceeds this value, 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.

  In the electron acceleration layer 4, as shown in FIG. 1, conductive fine particles 6 and insulator fine particles 5 are dispersed. Furthermore, the electron acceleration layer 4 may contain a binder component 15.

  Further, the electron acceleration layer 4 may be composed of a fine particle layer including the insulating fine particles 5, and the conductive fine particles 6 may be discretely arranged on at least the surface of the fine particle layer. Here, the fine particle layer may include conductive fine particles 6 in addition to the insulating fine particles 5. If the fine particle layer contains the conductive fine particles 6, the conductive fine particles 6 can change the electric conduction of the surface of the insulator fine particles 5, so that the conductivity of the element can be easily controlled.

The insulating fine particles 5 can be used without particular limitation as long as the material has insulating properties. However, the weight ratio of the insulating fine particles 5 to the whole fine particles constituting the electron acceleration layer 4 is preferably 80 to 95%. 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.

  The average particle diameter of the insulating fine particles 5 is preferably larger than the average particle diameter of the conductive fine particles 6 in order to obtain a heat radiation effect superior to that of the conductive fine particles 6. 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. If the insulating fine particles 5 are larger than the average particle size of the conductive fine particles 6, the conductive fine particles 6 smaller than the average particle size of the insulating fine particles 5 are efficiently conducted from the inside to the outside, and a current flows in the element. Joule heat generated at the time 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 4 can be easily adjusted.

  Further, when the electron acceleration layer 4 is formed by applying the conductive fine particles 6 on the fine particle layer including the insulating fine particles 5 as described later, the degree of penetration of the conductive fine particles 6 into the fine particle layer is determined by the insulating fine particles 5. It depends on the type and / or average particle size, the type and / or average particle size of the conductive fine particles 6, the combination of the insulating fine particles 5 and the conductive fine particles 6, and the like. That is, when the average particle diameter of the insulating fine particles 5 is small, most of the applied conductive fine particles 6 do not penetrate into the fine particle layer and deposit on the upper part. On the other hand, when the average particle diameter of the insulating fine particles 5 is large, the gaps between the particles of the fine particle layer become too large, and the conductive fine particles 6 staying in the fine particle layer are reduced. Therefore, in order to control the degree of penetration of the conductive fine particles into the fine particle layer when using the conductive fine particles 6 having an average particle diameter of 3 to 10 nm, the average particle diameter of the insulating fine particles 5 is 10 to 500 nm. preferable.

  As will be described later, when the electron acceleration layer 4 contains a binder component, if the average particle size of the insulating fine particles 5 is larger than 200 nm, most of the applied conductive fine particles having an average particle size of 3 to 10 nm It does not stay on top of the binder component layer containing the insulating fine particles 5. Therefore, when the electron acceleration layer 4 contains a binder component and the conductive fine particles 6 having an average particle diameter of 3 to 10 nm are used, the average particle diameter of the insulating fine particles 5 is preferably 10 to 200 nm.

  As the material of the conductive fine particles 6, any conductor can be used on the principle of operation of generating ballistic electrons. However, if the conductor has a high anti-oxidation power, it is possible to avoid oxidative degradation when operated at atmospheric pressure. Here, the high antioxidant power means that the oxide forming 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. The conductive fine particles having high anti-oxidation power can prevent device 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.

  Examples of the conductive fine particles having high anti-oxidation power include materials such as noble metals 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, the average particle diameter of the conductive fine particles 6 is more preferably 3 to 10 nm. Thus, by setting the average particle diameter of the conductive fine particles 6 to preferably 3 to 10 nm, a conductive path by the conductive fine particles 6 is not formed in the electron acceleration layer 4, and dielectric breakdown in the electron acceleration layer 4 is achieved. Is less likely to occur. Although there are many unclear points in principle, ballistic electrons are efficiently generated by using the conductive fine particles 6 having an average particle diameter within 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 particle 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.

  In addition, the conductive fine particles 6 are preferably subjected to a surface treatment in order to improve dispersibility when preparing a dispersion of conductive fine particles in the production method described later, and the surface treatment is performed on the above insulating coating substance. It may be to coat.

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

  The electron acceleration layer 4 may contain a binder component. In this case, the insulating fine particles 5 and the conductive fine particles 6 are dispersed in the binder component. As such a binder component, for example, adhesiveness with the electrode substrate 2 is good, and the insulating fine particles 5 and the conductive fine particles 6 can be dispersed, and an insulating binder resin may be used. Examples of such binder resins include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltriethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, hydrolyzable group-containing siloxane, vinyl Trimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyl Triethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, -2 (aminoethyl) 3-aminopropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl -N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane Bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanatopropyltriethoxysilane, and the like. These binder resins can be used alone or in combination of two or more.

  In the fine particle layer containing the binder component, the dispersed state of the insulating fine particles 5 is maintained, so that the insulating fine particles in the fine particle layer can be applied even when the conductive fine particle dispersion is applied using an electrostatic spraying method as will be described later. The dispersion state of 5 does not change. Therefore, the electron acceleration layer 4 in which the electron emission portion is uniformly controlled can be formed, and the electron-emitting device 1 capable of stable and good electron emission can be manufactured. Furthermore, the binder component has high adhesiveness with the electrode substrate, and can increase the mechanical strength of the element.

  Here, when the electron acceleration layer 4 is composed of a fine particle layer containing insulating fine particles and conductive fine particles are discretely arranged on at least the surface of the fine particle layer, the arrangement location becomes an electron emission portion. Therefore, the electron-emitting device 1 has a structure in which the electron-emitting portion is patterned. Therefore, the position of the electron emission portion can be controlled, and the phenomenon that the constituent material of the thin film electrode 3 formed on the electron acceleration layer 4 disappears due to the emitted electrons can be prevented. Moreover, the amount of electron emission from each electron emission part can be controlled independently.

  In an element in which conductive fine particles are discretely arranged on the surface of the fine particle layer, after forming the fine particle layer, for example, as described later, a conductive fine particle dispersion is applied using an electrostatic spray method using a mask. To make. At that time, since the dispersed state of the insulating fine particles is maintained in the fine particle layer containing the binder component, even if the conductive fine particle dispersion is applied later, the dispersed state of the insulating fine particles in the fine particle layer may change. There is no. Therefore, an electron acceleration layer with improved controllability of electron emission positions can be formed, and an electron-emitting device capable of stable and good electron emission can be obtained.

  Further, when conductive fine particles are also present inside the electron acceleration layer 4, the conductive fine particles 6 are present only below the landing position of the conductive fine particles on the surface of the fine particle layer. That is, the conductive fine particles are also present inside the electron acceleration layer 4. These discrete states are held.

  In addition, when the conductive fine particles are discretely arranged on the surface of the fine particle layer, if the fine particle layer contains a binder component, it is a factor for controlling the degree of penetration of the conductive fine particles into the fine particle layer. You may let them. In order to disperse the conductive fine particles on the surface of the fine particle layer, for example, (1) From the fine particle layer in which the insulating fine particles having a small diameter are closely packed, the conductive fine particles having the same diameter as the insulating fine particles are applied. (2) Forming a fine particle layer using a relatively high-viscosity insulator fine particle dispersion, and applying conductive fine particles thereon, (3) Controlling the drying rate of the conductive fine particle dispersion, etc. Is also possible.

  Furthermore, a plurality of electron-emitting devices 1 may be formed on a common electrode substrate including a flat surface or a curved surface. Thus, if a plurality of electron-emitting devices can be formed on a common electrode substrate, it can be suitably used in an apparatus that requires a plurality of electron-emitting devices.

  Next, the principle of electron emission will be described. Most of the electron acceleration layer 4 is composed of a fine particle layer including the insulating fine particles 5, and the conductive fine particles 6 exist only in the upper part of the fine particle layer or in the upper part and the inside. The ratio of the insulating fine particles 5 and the conductive fine particles 6 in the electron acceleration layer 4 is such that the weight ratio of the insulating fine particles 5 to the total weight of the insulating fine particles 5 and the conductive fine particles 6 corresponds to 80%. The conductive fine particles 6 attached per particle are about six particles. The electron acceleration layer 4 is a layer including the insulating fine particles 5 and a small number of conductive fine particles 6 and has semiconductivity.

  When the binder component is included in the electron acceleration layer 4, most of the electron acceleration layer 4 is composed of the insulating fine particles 5 and the fine particle layer containing the binder component, and the conductive fine particles 6 are formed only on the upper portion of the fine particle layer or on the upper portion and the inside thereof. Existing. The electron acceleration layer 4 includes insulating fine particles 5 and a fine particle layer containing a binder component and a small number of conductive fine particles 6 and 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.

  Further, when all of the conductive fine particles 6 are discretely arranged on the surface of the fine particle layer composed of the insulating fine particles in the electron acceleration layer 4, the electron emission mechanism of the electron-emitting device is not clear. I think that it is the following mechanism. When a voltage is applied between the electrode substrate 2 and the thin film electrode 3, electrons move from the electrode substrate 2 to the surface of the insulating fine particles 5. Since the inside of the insulating fine particles 5 has a high resistance, electrons are conducted through the surface of the insulating fine particles 5. At this time, electrons are trapped at impurities on the surface of the insulating fine particles 5, a surface treatment agent, or contacts between the insulating fine particles 5. The trapped electrons work as fixed charges. As a result, the applied voltage and the electric field created by the trapped electrons are combined on the surface of the electron acceleration layer 4 to form a high electric field. The electrons are accelerated by the high electric field, and conductive fine particles (electron emission portions) arranged discretely are formed. As a result, electrons are emitted from the thin-film electrode 3.

  Next, a method for manufacturing the electron-emitting device 1 according to the present invention will be described.

First, an insulating fine particle dispersion in which the insulating fine particles 5 are dispersed in a dispersion solvent is obtained. For example, it can be obtained by dispersing the insulating fine particles 5 in a dispersion solvent. The dispersion method is not particularly limited, and for example, it may be dispersed by applying an ultrasonic disperser at room temperature. The dispersion solvent used here can be used without particular limitation as long as the insulating fine particles 5 can be dispersed and dried after coating. For example, toluene, benzene, hexane, methanol, ethanol and the like can be mentioned. Here, the dispersion solvent suitable for dispersion varies depending on the type of the insulating fine particles 5. For example, when the insulating fine particles 5 are SiO ₂ , methanol or ethanol is preferable. Moreover, a dispersion | distribution solvent can be used individually or in combination of 2 or more types, respectively.

  Further, when the electron acceleration layer 4 includes a binder component, an insulating fine particle-containing binder component dispersion liquid dispersed in the insulating fine particles 5, the binder component, and the dispersion solvent is obtained. The dispersion solvent used here can be used without particular limitation as long as it can disperse the insulating fine particles 5 and the binder component and can be dried after coating. For example, methanol, ethanol, propanol, 2-propanol, butanol, 2 -Butanol and the like. These dispersion 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 insulating fine particles is preferably 1 to 50% by weight. When the amount is less than 1% by weight, the effect of adjusting the resistance of the electron acceleration layer 4 as an insulator is not exerted. When the amount is more than 50% by weight, aggregation of the insulator fine particles 5 occurs. Especially, it is more preferable that it is 1 to 20 weight%.

  Next, a conductive fine particle dispersion in which the conductive fine particles 6 are dispersed in a dispersion solvent is obtained. For example, the conductive fine particles 6 may be dispersed in a dispersion solvent, or a commercially available product may be used. The dispersion method is not particularly limited, and for example, it may be dispersed using an ultrasonic disperser at room temperature. Any dispersion solvent can be used without particular limitation as long as the conductive fine particles 6 can be dispersed and dried after coating. Here, in order to improve the dispersibility, when the conductive fine particles 6 are subjected to a surface treatment, it is preferable to use a dispersion solvent suitable for dispersion depending on the surface treatment method. For example, toluene or hexane is preferable for the conductive fine particles 6 whose surface is treated with alcoholate.

  Further, as the conductive fine particle dispersion, a nano colloid liquid of conductive fine particles 6 may be used in a liquid state. When the nano colloidal liquid of the conductive fine particles 6 is used in a liquid state, a dispersion in which the conductive fine particles 6 are uniformly dispersed can be applied without agglomeration. Therefore, the electron accelerating layer 4 in which the conductive fine particles 6 are present more uniformly exists on the fine particle layer, and the electron-emitting device 1 capable of stable and good electron emission can be manufactured. The conductive fine particles 6 preferably have an average particle size in a colloidal state of 0.35 μm or less. By using conductive fine particles having an average particle size in the colloidal state of 0.35 μm or less, the dispersibility in the electron acceleration layer 4 can be enhanced as described in Examples described later. Examples of the nano colloid liquid of the conductive fine particles 6 include gold nano particle colloid liquid manufactured and sold by Harima Kasei Co., Ltd., silver nano particles manufactured and sold by Applied Nano Laboratory, and platinum nano manufactured and sold by Tokuru Chemical Laboratory Co., Ltd. Examples thereof include a particle colloid solution and a palladium nanoparticle colloid solution, and a nickel nanoparticle paste manufactured and sold by IOX Co., Ltd. In addition, as the solvent of the nano colloid liquid of the conductive fine particles 6, the insulating fine particles 5 can be used without particular limitation as long as the fine particles can be colloidally dispersed and dried after coating. For example, toluene, benzene, xylene, hexane, tetradecane, etc. Can be used.

  Then, the insulating fine particle dispersion or the insulating fine particle-containing binder component dispersion prepared as described above is applied onto the electrode substrate 2 to obtain a layer (fine particle layer) of the insulating fine particles 5 (fine particle layer forming step). This coating may be performed using, for example, a spin coating method. The conditions for using the spin coating method for forming the fine particle layer are not particularly limited, but the rotation speed is preferably 1000 rpm or more and less than 10,000 rpm, particularly preferably 3000 rpm or more and less than 8500 rpm. The film thickness of the fine particle layer formed under these conditions is appropriate, and it is possible to make the thickness of the electron acceleration layer uniform and to adjust the resistance of the electron acceleration layer in the layer thickness direction. 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.

  Subsequently, the conductive fine particle dispersion prepared as described above is applied onto the fine particle layer (conductive fine particle application step). Here, if the fine particle layer is dried at normal temperature and does not change with time, the conductive fine particle dispersion may be applied continuously.

  The conductive fine particle dispersion is applied by electrostatic spraying. The conditions for using the electrostatic spray method for applying the conductive fine particle dispersion are not particularly limited, but the inner diameter of the syringe is preferably 0.11 mm or more and less than 2.16 mm, and preferably 0.21 mm or more and less than 0.51 mm. Particularly preferred. If it is less than 0.11 mm, the occurrence of clogging increases. On the other hand, at 2.16 mm or more, the conductive fine particles remaining on the fine particle layer are excessively large, a metal layer is formed between the electron acceleration layer and the thin film electrode, and accelerated electron scattering occurs. Decrease. Further, since the amount of conductive fine particles soaked into the insulating fine particle-containing binder component layer is large, a conductive path is easily formed, a large current flows in the element at a low voltage, and the amount of electron emission decreases. The flow rate of the liquid is preferably 0.2 μL / min or more and less than 10 mL / min, and particularly preferably 1.0 μL / min or more and less than 1.0 mm / min. Here, the degree of penetration of the conductive fine particles into the fine particle layer containing the insulating fine particles depends on the type and / or average particle size of the insulating fine particles, the type and / or average particle size of the conductive fine particles, and the combination of the insulating fine particles and the conductive fine particles. In addition to the above, it also depends on the discharge volume of the conductive fine particle dispersion. That is, if the ejection volume is too small, the droplets are small and the amount of the conductive fine particles soaked into the fine particle layer is small, so that most of the applied conductive fine particles do not penetrate into the fine particle layer including the insulating fine particles 5, Deposit on top. On the other hand, when the discharge volume is too large, the conductive fine particles remaining on the fine particle layer become excessively large, and the amount of electron emission decreases due to the same phenomenon as described above. Further, since the amount of the conductive fine particles soaked into the fine particle layer is large, the amount of electron emission decreases as in the above phenomenon.

  As described above, the insulating fine particle dispersion and the conductive fine particle dispersion are respectively prepared, and the conductive fine particle 6 dispersion is applied onto the fine particle layer including the insulating fine particles 5 by the electrostatic spraying method. The electron acceleration layer 4 is formed.

  Thus, the electron acceleration layer 4 is formed. After the formation of the electron acceleration layer 4, 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.

  Here, the electron emission amount of the electron-emitting device 1 does not increase in proportion to the amount of the conductive fine particles 6 in the electron acceleration layer 4, but the inside of the electron acceleration layer 4 becomes a ballistic electron. It only needs to be semiconductive so that is released. Therefore, the amount of conductive fine particles required in the electron acceleration layer 4 may be small. On the other hand, in order to obtain a device with uniform performance, the electron emission portion, which is a region where conductive fine particles are introduced, must not be unevenly distributed. Therefore, for device production, a dispersion medium with good dispersibility is selected for each fine particle, and a small amount of conductive fine particle dispersion is uniformly applied on the fine particle layer containing the insulating fine particles, and the upper part or the inside of the fine particle layer, or It is required that the conductive fine particles exist uniformly in the upper and inner regions where the conductive fine particles are introduced.

  In the manufacturing method described above, in the step of forming the electron acceleration layer 4, a fine particle layer including the insulating fine particles 5 is formed, and a conductive fine particle dispersion is applied onto the fine particle layer by using an electrostatic spray method. By this method, the conductive fine particles can be present in a small amount and uniformly in the upper part or inside of the fine particle layer, or in the upper and inner regions where the conductive fine particles are introduced. Therefore, it is possible to manufacture an electron-emitting device that has an electron-emitting portion uniformly and can stably and satisfactorily emit electrons. In addition, by applying a voltage to the electrode substrate 2 and the spray needle after forming the fine particle layer and electrostatically spraying the conductive fine particle dispersion solution, the conductive fine particles reach the fine particle layer without diffusing, and wasteful conductive fine particles are consumed. Can be suppressed. In addition, since the electrostatic spraying method is used, the conductive fine particles can be uniformly introduced regardless of the shape of the fine particle layer, and the electron emission portion, which is the region where the conductive fine particles are introduced, can be formed on the curved surface. The shape of the emitting element can be manufactured without limitation.

  Furthermore, according to the manufacturing method described above, since the insulating fine particle dispersion solution and the conductive fine particle dispersion solution are prepared separately and applied onto the electrode substrate, the aggregate during mixing of the insulating fine particle dispersion solution and the conductive fine particle dispersion solution And the occurrence of agglomerates when conductive fine particles are added to the insulating fine particle dispersion can be prevented. Therefore, after applying the insulating fine particle dispersion on the electrode substrate 2 to form a fine particle layer containing the insulating fine particles, the conductive fine particle dispersion is applied, so that the aggregate of the fine particles is small and the fine particles are uniformly dispersed. The formed electron acceleration layer can be formed. In addition, the electron-emitting device 1 can be obtained simply and at a low cost by a simple manufacturing process of applying a fine particle dispersion.

  As described above, according to the method of the present invention, it is possible to avoid the generation of aggregates of fine particles, and conductive fine particles are introduced into the upper part or the inner part of the fine particle layer including the uniformly dispersed insulating fine particles, or the upper part and the inner part. The electron acceleration layer 4 in which the electron emission portions are uniformly present in the region can be formed easily and at low cost, and the electron-emitting device 1 that emits electrons stably and satisfactorily can be manufactured.

  In addition, when conductive fine particles are applied after forming a fine particle layer containing a binder component using a binder component dispersion containing an insulating fine particle, the dispersed state of the insulating fine particles is maintained in the fine particle layer containing the binder component. Even when the conductive fine particle dispersion is applied using the electrostatic spraying method, the dispersion state of the insulating fine particles in the fine particle layer does not change. Therefore, an electron acceleration layer in which the electron emission portion is uniformly controlled can be formed, and an electron-emitting device capable of stable and good electron emission can be manufactured.

  Moreover, since the electron emission part which is the area | region where the conductive fine particle 6 was introduce | transduced in the element is formed by an electrostatic spraying method, this electron emission part is obtained also on a curved surface, and the shape of the electron emission element 1 is not limited. Therefore, the electron-emitting device 1 can be installed in devices having various shapes, and the range of devices that can be applied is wide.

  Further, according to the above manufacturing method, even when the dispersion solvent that is easily dispersed between the insulating fine particles 5 and the conductive fine particles 6 is different, the fine particle layer is formed by applying the insulating fine particle dispersion without mixing them. Later, by applying a conductive fine particle dispersion, an electron acceleration layer can be formed while maintaining the dispersibility of both fine particles. That is, the insulating fine particles 5 and the conductive fine particles 6 include an aggregate of insulating fine particles, an aggregate of conductive fine particles, and an aggregate of the insulating fine particles 5 and the conductive fine particles 6 even if the dispersion solvent having high dispersibility is different. A uniform electron acceleration layer can be formed.

  In addition, although the dispersion solvent suitable for an electrostatic spraying method is not specifically limited, THF, DMF, hexane, etc. are used.

  In the manufacturing method, a mask may be installed on the fine particle layer, and the conductive fine particle dispersion may be applied using an electrostatic spraying method. The mask to be used may be a metal mask or another mask, and is not particularly limited. By installing the mask in this way, when the conductive fine particle dispersion is applied using the electrostatic spraying method and then the mask is removed, the conductive fine particles 6 are unevenly distributed in the places where the mask is not formed, and the mask is not present. The conductive fine particles 6 are not very dispersed in the locations. Therefore, the dispersion liquid of conductive fine particles can be applied to any location in the fine particle layer. By controlling the size of the mask and the size of the unmasked area, the arrangement of the electron acceleration layer on the common electrode substrate can be patterned, and the electron emission that is a region where conductive fine particles are introduced for each element The part can be patterned. Further, since the electrostatic spraying method is used, the conductive fine particles 6 are uniformly dispersed in the region where the conductive fine particles 6 are introduced.

  Further, by forming the thin film electrodes on the patterned electron emission portions so as to be insulated from each other, each becomes the electron emission device 1. Thus, a plurality of electron emission devices 1 are formed on the common electrode substrate 2 at a time. can do. The plurality of electron-emitting devices formed on the common electrode substrate 2 can independently control the amount of electron emission. For example, in the case where the electron emission device 10 as shown in FIG. 2 is used for the charging device 90, a plurality of electron emission portions can be used as the electron emission devices 1, respectively. By controlling, the effect of improving the uniformity of charging of the photoconductor 11 can be obtained. The application of the electron emission device 10 to the charging device 90 will be described in the second embodiment. Thus, if a plurality of electron-emitting devices can be formed on a common electrode substrate, it can be suitably used in an apparatus that requires a plurality of electron-emitting devices.

(Example)
In the following examples, an experiment in which current is measured using an electron-emitting device manufactured using the manufacturing method 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 3 were produced as follows. And about the produced electron emission element, 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. Such an experimental system was placed in a vacuum of 1 × 10 ⁻⁸ ATM to perform each electron emission experiment. In each experiment, the distance between the electron-emitting device and the counter electrode was 5 mm across the insulator spacer 9. Moreover, it measured by the applied voltage V2 = 100V to a counter electrode.

Example 1
Into a 10 mL reagent bottle, 2.4 g of hexane as a dispersion solvent and 0.5 g of spherical silica particles having an average particle diameter of 110 nm as the insulator fine particles 5 are placed, and this reagent bottle is placed in an ultrasonic disperser to obtain an insulator fine particle dispersion A Was prepared. The content of the insulating fine particles 5 in the insulating fine particle dispersion A was 17% by weight.

  Next, after the insulator fine particle dispersion A was dropped on a 30 mm square SUS substrate as the electrode substrate 2, the fine particle layer I was formed by spinning at 4500 rpm for 10 seconds using a spin coating method. Then, it is dried at room temperature for 1 hour, and a silver nanoparticle-containing hexane is used as a conductive fine particle dispersion (here, a nanocolloid liquid of conductive fine particles) in which the conductive fine particles 6 are dispersed in a dispersion solvent on the fine particle layer I obtained. A dispersion solution (manufactured by Applied Nanoparticles Laboratory, average particle diameter of silver fine particles 4.5 nm, solid content concentration of silver fine particles 7%) was applied by electrostatic spraying. The conditions for electrostatic spraying were a liquid flow rate of 2 μL / min, a syringe inner diameter of 0.41 mm, a distance from the spray needle to the electrode substrate 2 of 8 cm, and an applied voltage of 5 V between the electrode substrate 2 and the spray needle.

  The silver nanoparticle-containing hexane dispersion solution was applied onto the fine particle layer I by electrostatic spraying, and then allowed to stand for 1 hour and air-dried to infiltrate the silver nanoparticles into the fine particle layer I, thereby forming the electron acceleration layer 4.

Thereafter, the thin film electrode 3 was formed on the surface of the electron acceleration layer 4 using a magnetron sputtering apparatus, whereby the electron-emitting device of Example 1 was obtained. Gold was used as the film forming material, the layer thickness of the thin film electrode 3 was 40 nm, and the area was 0.014 cm ² .

The electron-emitting device of Example 1 has an electron emission current of 0.20 mA / cm ² per unit area at an applied voltage V1 = 16.8 V to the thin film electrode in a vacuum of 1 × 10 ⁻⁸ ATM. An internal current of 264 mA / cm ² and an electron emission efficiency of 0.074% were confirmed.

(Example 2)
In a 10 mL reagent bottle, 2.0 g of ethanol as a dispersion solvent and 0.5 g of methyltrimethoxysilane KBM-13 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a binder component are added, and the insulating fine particles 5 have an average particle size of 40 nm. 0.5 g of spherical silica particles AEROSIL RX50 (manufactured by Evonik Exa Japan Co., Ltd.) were added, and the reagent bottle was put on an ultrasonic dispersing device to prepare a binder component dispersion liquid B containing insulating fine particles. The content of the insulating fine particles 5 in the insulating fine particle-containing binder component dispersion B was 17% by weight.

  Next, an insulating fine particle-containing binder component dispersion liquid B was dropped on a 30 mm square SUS substrate as the electrode substrate 2 and then rotated at 3500 rpm for 10 seconds to form a fine particle layer II using a spin coating method. Thereafter, it is dried at room temperature for 24 hours, and a silver nanoparticle-containing hexane is obtained as a conductive fine particle dispersion (here, a nanocolloid liquid of conductive fine particles) in which the conductive fine particles 6 are dispersed in a dispersion solvent on the obtained fine particle layer II. A dispersion solution (manufactured by Applied Nanoparticles Laboratory, average particle diameter of silver fine particles 4.5 nm, solid content concentration of silver fine particles 7%) was applied by electrostatic spraying. The conditions for electrostatic spraying were a liquid flow rate of 2 μL / min, a syringe inner diameter of 0.41 mm, a distance from the spray needle to the electrode substrate 2 of 8 cm, and an applied voltage of 5 V between the electrode substrate 2 and the spray needle.

The silver nanoparticle-containing hexane dispersion solution was applied onto the fine particle layer II by electrostatic spraying, and then allowed to stand for 1 hour and air-dried to infiltrate the silver nanoparticles into the fine particle layer II, thereby forming the electron acceleration layer 4.
The silver nanoparticle-containing hexane dispersion solution was applied by electrostatic spraying, and then allowed to stand for 1 hour and air-dried to infiltrate the silver nanoparticles.

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

The electron-emitting device of Example 2 has an electron emission current of 0.10 mA / cm ² per unit area at a voltage V1 = 23.4 V applied to the thin film electrode in a vacuum of 1 × 10 ⁻⁸ ATM. An internal current of 25 mA / cm ² and an electron emission efficiency of 0.40% were confirmed.

(Example 3)
A conductive fine particle dispersion liquid in which a metal mask of 0.10 × 0.14 cm ² is placed on the fine particle layer II (containing the binder component) obtained in Example 2 and the conductive fine particles 6 are dispersed in a dispersion solvent ( Here, silver nanoparticle-containing tetradecane dispersion solution (manufactured by ULVAC, Inc., average particle diameter of silver fine particles of 5.0 nm, silver fine particle solid content concentration of 54%) is applied as a conductive fine particle nanocolloid solution by electrostatic spraying. did. The conditions for electrostatic spraying were a liquid flow rate of 2 μL / min, a syringe inner diameter of 0.41 mm, a distance from the spray needle to the electrode substrate 2 of 8 cm, and an applied voltage of 5 V between the electrode substrate 2 and the spray needle.

  After the silver nanoparticle-containing tetradecane dispersion solution was applied onto the fine particle layer II by electrostatic spraying, it was allowed to stand for 24 hours and air-dried to infiltrate the silver nanoparticles into the fine particle layer II, thereby forming the electron acceleration layer 4.

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

The electron-emitting device of Example 3 has an electron emission current of 0.31 mA / cm ² per unit area at a voltage of V1 = 26.5 V applied to the thin film electrode in a vacuum of 1 × 10 ⁻⁸ ATM. An internal current of 112 mA / cm ² and an electron emission efficiency of 0.27% were confirmed.

[Embodiment 2]
FIG. 4 shows an example of a charging device 90 according to the present invention using the electron emission device 10 according to the present invention described in the first embodiment. The charging device 90 includes an electron-emitting device 10 having 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 emission device 10 used as the charging device 90 is not accompanied by discharge, 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 emission device 10 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 has high electron emission efficiency, the charging device 90 can be charged efficiently.

  Further, since the electron emission device 10 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 emission apparatus 10 according to the present invention described in the first embodiment. The electron beam curing device 100 includes an electron emission device 10 having an electron emission element 1 and a power source 7 that applies a voltage to the electron emission 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 (cured object) 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.

  In contrast, the electron beam curing apparatus according to the present invention using the electron emission device 10 can irradiate the electron beam efficiently because the electron emission efficiency of the electron emission element 1 is high. 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 10 according to the present invention described in the first embodiment.

  A self-light-emitting device 31 shown in FIG. 6 includes an electron-emitting device having the electron-emitting device 1 and a power source 7 for applying a voltage to the electron-emitting device 1, and a glass serving as a base material at a position facing away from and The substrate 34, the ITO film 33, and the phosphor 32 include 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 layer of the phosphor 32 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. Film. 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 10 having an electron-emitting device 1 and a power source 7 for applying a voltage to the electron-emitting device 1, and further, as a phosphor 32 ′ 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-mentioned phosphor fine particles generally have a low electric resistance, and the insulator fine particles 5 are mixed. 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 kept small, for example, the insulator fine particles 5. When using spherical silica particles (average particle size 110 nm) as the phosphor fine particles and ZnS: Mg (average particle size 500 nm) as the phosphor fine particles, 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 and 32 to emit light. Since the electron-emitting device 1 has high electron emission efficiency, the self-light-emitting device. 31, 31 ′, 31 ″ can emit light efficiently. Note that the self-light emitting devices 31, 31 ', 31' 'can emit light more efficiently if they are vacuum-sealed to increase the electron emission current.

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 device according to the present invention using the electron emission device 10 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 emission device 10 having an electron emission element 1 and a power source 7 that applies a voltage to the electron emission element 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. Furthermore, since the electron emission element 1 has high electron emission efficiency, the air blowers 150 and 160 can be cooled more efficiently.

  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 be manufactured simply and at low cost with a small amount of conductive fine particles uniformly present, and stable and good electron emission is possible. Thus, for example, a self-luminous device, an image display device, or emitted electrons are generated by combining with a charging device, an electron beam curing device, or a light emitter of an image forming apparatus such as an electrophotographic copying machine, a printer, or a facsimile. By using the ion wind to be applied, it 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 6 Conductive fine particle 7 Power supply (power supply part)
8 Counter electrode 9 Insulator spacer 10 Electron emission device 11 Photoreceptor 15 Binder component 21 Accelerating electrode 22 Resist (cured material)
31, 31 ', 31 "Self-luminous device 32, 32' Phosphor (light emitter)
33 ITO film 34 Glass substrate 35 Power source 36 Light emitting unit 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 (29)

An electrode substrate, a thin film electrode, and an electron acceleration layer including conductive fine particles and insulator fine particles sandwiched between the electrode substrate and the thin film electrode, and a voltage is applied between the electrode substrate and the thin film electrode. When applied, the electron acceleration layer accelerates electrons in the electron acceleration layer and emits the electrons from the thin film electrode.
The step of forming the electron acceleration layer includes
On the electrode substrate, a fine particle layer forming step of forming a fine particle layer containing insulating fine particles by applying an insulating fine particle dispersion in which the insulating fine particles are dispersed in a dispersion solvent;
A method for manufacturing an electron-emitting device, comprising: applying a conductive fine particle dispersion in which the conductive fine particles are dispersed in a dispersion solvent to the fine particle layer using an electrostatic spray method.   The method of manufacturing an electron-emitting device according to claim 1, wherein the insulating fine particle dispersion and the conductive fine particle dispersion contain different dispersion solvents.   3. The method of manufacturing an electron-emitting device according to claim 1, wherein the insulating fine particle dispersion contains a binder component.   The method for manufacturing an electron-emitting device according to any one of claims 1 to 3, wherein the conductive fine particle dispersion is a nanocolloid liquid of the conductive fine particles.   5. The conductive fine particle application step according to claim 1, wherein a mask is placed on the fine particle layer, and the conductive fine particle dispersion is applied using an electrostatic spraying method. A method for manufacturing an electron-emitting device.   An electron-emitting device manufactured by the method for manufacturing an electron-emitting device according to claim 1. 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 accelerating layer is composed of a fine particle layer containing insulating fine particles, and conductive fine particles are discretely arranged at least on the surface of the fine particle layer. 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 accelerating layer includes insulating fine particles and conductive fine particles, and a plurality of the electron accelerating layers are formed on a common electrode substrate including a flat surface or a curved surface.   The electron-emitting device according to any one of claims 6 to 8, wherein the conductive fine particles have an average particle diameter of 3 to 10 nm.   10. The electron-emitting device according to claim 6, wherein an average particle diameter of the insulating fine particles is larger than an average particle diameter of the conductive fine particles and is 10 to 500 nm.   The electron-emitting device according to any one of claims 6 to 10, wherein the conductive fine particles are a conductor having a high anti-oxidation power.   The electron-emitting device according to claim 6, wherein the conductive fine particles are a noble metal.   The electron-emitting device according to any one of claims 6 to 12, wherein the conductive material forming the conductive fine particles contains at least one of gold, silver, platinum, palladium, and nickel. The insulating fine particles _{is, SiO 2, Al 2 O 3} , and characterized in that it comprises TiO ₂ in which at least one, or an organic polymer, in any one of claims 6 13 The electron-emitting device described.   15. The electron-emitting device according to claim 6, wherein a ratio of the conductive fine particles in the electron acceleration layer is 0.5 to 30% by weight.   The electron-emitting device according to claim 15, 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 6 to 16, wherein the electron acceleration layer has a thickness of 12 to 6000 nm.   The electron-emitting device according to claim 17, wherein the electron acceleration layer has a thickness of 300 to 6000 nm.   The electron-emitting device according to any one of claims 6 to 18, wherein the thin-film electrode includes at least one of gold, silver, carbon, tungsten, titanium, aluminum, and palladium.   The electron-emitting device according to any one of claims 6 to 19, 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 20, wherein the small insulator material includes at least one of alcoholate, fatty acid, and alkanethiol.   The electron-emitting device according to any one of claims 6 to 21, and a power supply unit that applies a voltage between the electrode substrate and the thin-film electrode included in the electron-emitting device. Electron emission device.   23. A charging device comprising the electron-emitting device according to claim 22, 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 23.   An electron beam curing device comprising the electron emission device according to claim 22, wherein the material to be cured is cured by emitting electrons from the electron emission device.   A self-luminous device comprising the electron-emitting device according to claim 22 and a light emitter, wherein the light-emitting device emits electrons by emitting electrons from the electron-emitting device.   An image display apparatus comprising the self-luminous device according to claim 26. 23. A blower device comprising the electron emission device according to claim 22, wherein electrons are emitted from the electron emission device to blow air.   23. A cooling device comprising the electron-emitting device according to claim 22, wherein the object to be cooled is cooled by emitting electrons from the electron-emitting device.

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