JP2011009073A - Electron-emitting element, its manufacturing method and electron-emitting device, self-luminous device, and image display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of an electron-emitting element which can maintain electron emission characteristics for a long period by avoiding a situation where an electrode on the electron emission side is lost gradually accompanying electron emission, and to provide its manufacturing method.SOLUTION: The electron-emitting element 1 includes an electron acceleration layer 4 between an electrode substrate 2 and a thin-film electrode 3. The electron acceleration layer 4 includes a particulate layer 105 containing insulator particulates located on the electrode substrate 2 side and includes a deposition 106 of conductive particulates on the surface of the particulate layer 105. Then, a conductive route is formed beforehand on the electron acceleration layer 4, and an electron emission part consisting of a physical defect which corresponds to an outlet of the conductive route is formed on the deposition 106. The electrons are emitted from this electron emission part 108.

Description

  The present invention relates to an electron-emitting device that emits electrons by applying a voltage, a manufacturing method thereof, an electron-emitting device, a self-luminous device, and an image display device.

  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 portion, the emitted electrons easily obtain large energy by the electric field and easily ionize gas molecules. There is a problem that positive ions generated by ionization of gas molecules are accelerated and collided in the direction of the surface of the electron-emitting device due to a strong electric field, and the electron-emitting device is destroyed by sputtering.

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

  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 accelerate electrons using the quantum size effect and strong electric field inside the electron-emitting device to 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, in the MIM type and MIS type electron-emitting devices, as in the Spindt-type, CNT-type, and BN-type electron-emitting devices, there is a problem of being destroyed by sputtering due to ionization of gas molecules and a problem of generating ozone. Can be overcome.

  For example, in Patent Document 1, an insulator film in which fine particles such as metal are dispersed is provided between two electrodes, electrons are injected from one electrode (substrate electrode) into the insulator film, and the injected electrons are injected. Has been disclosed in which an electron is emitted through the other electrode (electron emission side electrode) having a thickness of several tens of thousands to 1,000 mm.

JP-A-1-298623 (published on December 1, 1991) Japanese Patent Laid-Open No. 1-279557 (published on November 9, 1991)

  However, in the configuration in which electrons are emitted from the electron emission side electrode as in Patent Document 1, there is a problem that the electron emission side electrode is reverse sputtered by the emitted electrons. Reverse sputtering means that the electrode on the electron emission side becomes a target for sputtering by emitted electrons. For this reason, the metal material constituting the electrode on the electron emission side is gradually but surely lost. This phenomenon also applies to an electron-emitting device in which the electrode on the electron emission side is a solid electrode, and the metal material constituting the surface electrode disappears with time, and eventually the function as the electrode is lost.

  The present invention has been made in view of the above problems, and avoids a situation in which the electrode on the electron emission side gradually disappears along with electron emission, and an electron-emitting device capable of maintaining electron emission characteristics for a long period of time, and its The object is to provide a manufacturing method.

  In order to solve the above-described problems, an electron-emitting device of the present invention has an electron acceleration layer between an electrode substrate and a thin film electrode arranged to face each other, and a voltage is applied between the electrode substrate and the thin film electrode. Is applied to accelerate the electrons in the electron acceleration layer to emit the electrons from the thin film electrode, and the electron acceleration layer has a fine particle layer containing insulating fine particles. The fine particle layer is provided with a single substance or a mixed substance that enhances the flow of electricity in the thickness direction of the fine particle layer, and the electron acceleration layer has a conductive path passing through the electron acceleration layer in the thickness direction. In this case, a conductive path serving as an electron emitting portion that provides the electron to the thin film electrode at the path exit is formed in advance. Here, the pre-formation of the conductive path means that the voltage is applied to the device in a vacuum and before driving, that is, it is formed in the manufacturing process of the electron-emitting device. .

  According to the above configuration, by applying a voltage between the electrode substrate and the thin film electrode, a current flows in the electron acceleration layer, and a part of the current becomes a ballistic electron by the strong electric field formed by the applied voltage, and the thin film Released from the electrode side.

  Here, electrons are not emitted from an arbitrary portion on the thin film electrode side, but are emitted from an electron emission portion formed in advance in an electron acceleration layer located in the lower layer of the thin film electrode. The electron emission portion is an exit of a conductive path formed in the electron acceleration layer and passing through the electron acceleration layer in the thickness direction. Electrons emitted from the thin film electrode pass through the conductive path to the thin film electrode. Given and released.

  Such a conductive path (preliminarily formed conductive path) is caused by the action of a single substance or a mixed substance, which is imparted to the fine particle layer containing the insulating fine particles and enhances the flow of electricity in the thickness direction of the fine particle layer. It can be easily formed by a forming process in the atmosphere.

  In the atmosphere forming process, a DC voltage is applied between the electrode substrate and the thin film electrode in the atmosphere to form a conduction path for the current in the element that flows from the electrode substrate side to the thin film electrode side through the fine particle layer. It is processing to do.

  Since the conductive path is formed in the electron acceleration layer in advance by the forming process in the atmosphere, a new conductive path is not formed by voltage application to the element required for the subsequent electron emission operation in vacuum. The in-element current flows through a previously formed conductive path. As a result, the conductive path functions stably during electron emission. On the other hand, applying a voltage in a vacuum to an element that has not been subjected to the forming process in the atmosphere and has not previously been formed with a conductive path is a process of forming a conductive path and an electron emission process. It is. That is, electrons are emitted while forming a conductive path. The formation of the conductive path formed under such conditions is not constant, and is newly formed each time a voltage is applied in a vacuum. Therefore, every time a voltage is applied in vacuum, the conductive state of the device changes, and stable electron emission characteristics cannot be obtained. Thus, in the electron emission device of the present invention, an arbitrary portion of the electron acceleration layer is not obtained. Rather than being emitted from, the emission location is specified as the electron emission portion of the electron acceleration layer. Therefore, in the thin film electrode, the portion reversely sputtered by the emitted electrons is limited to a portion located directly above the electron emitting portion or a portion located near the electron emitting portion. Therefore, except for the portion located just above or near the electron emission portion in the thin film electrode, it is not exposed to electrons, the metal material constituting the thin film electrode is reverse sputtered by the emitted electrons, and disappears with time, Ultimately, the function as an electrode is not lost.

  In the electron-emitting device of the present invention, it is preferable that the single substance or the mixed substance is applied so that application positions are discrete when viewed from the upper surface of the fine particle layer.

  About the part which provides the single substance or mixed substance which raises the ease of electricity flow, the structure given to the whole surface of a fine particle layer may be sufficient. However, when forming the conductive path by performing the forming process, the conductive path is formed in a portion where current easily flows in the configuration applied to the entire surface, and the electron emission portion is determined accidentally. If the electron emission part is accidentally formed, the electron emission part is arbitrarily arranged on the surface of the thin film electrode to control the electron emission position in the thin film electrode, or to control the emission amount per unit area. I can't. The electron emission amount can also be controlled by changing the voltage applied between the electrode substrate and the thin film electrode. The electron emission amount is reduced at a low voltage, and the electron emission amount is increased at a high voltage. it can. However, the device of the present invention has an extremely small amount of electron emission when a low voltage is applied, and the electron emission efficiency is significantly reduced. For this reason, when it is desired to narrow down the electron emission amount extremely small, the control of the electron emission amount by the applied voltage is not used.

  On the other hand, according to the above configuration, the single substance or the mixed substance is provided so that the application positions when viewed from the upper surface of the fine particle layer are discrete. When the conductive path is formed, the conductive path through which the current in the element flows is formed with respect to the individual, single substance or mixed substance application parts discretely arranged from the electrode substrate side. An electron emitting portion is formed on the surface. In this way, by adopting a configuration in which the single substance or the mixed substance application portion is discretely arranged, the electron emission portion can be arbitrarily arranged in the thin film electrode surface, and electrons are emitted in the thin film electrode. It is possible to control the position, the discharge amount per unit area, and the like.

In the electron-emitting device of the present invention, the single substance or the mixed substance is conductive fine particles, and the conductive fine particles are deposited on the surface of the fine particle layer to form a deposit,
The deposit of the conductive fine particles may have a configuration in which a physical defect serving as the electron emission portion is provided.

  The single substance or the mixed substance can be, for example, conductive fine particles. Application of the conductive fine particles to the fine particle layer is realized by depositing conductive fine particles on the surface of the fine particle layer to form a deposit. The deposit of the conductive fine particles is provided with a physical defect that becomes an electron emission portion in the formation of the conductive path.

  In the electron-emitting device of the present invention, it is preferable that the fine particle layer further includes a binder resin for binding the insulating fine particles.

  According to the above configuration, since the insulating fine particles are bound to each other by the binder resin in the fine particle layer, the mechanical strength of the electron-emitting device can be increased. Further, when the single substance or the mixed substance is conductive fine particles, the fine particle layer is hardened with a binder resin, so that the conductive fine particles are more easily deposited on the surface of the fine particle layer than entering the fine particle layer. The configuration of the electron-emitting device of the present invention can be easily realized.

  In the electron-emitting device of the present invention, 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, the conductive fine particles may further include at least one of gold, silver, platinum, palladium, and nickel. As described above, since the conductive fine particles contain at least one of gold, silver, platinum, palladium, and nickel, the deterioration of the elements such as oxidation of the conductive fine particles due to oxygen in the atmosphere is further reduced. Can be effectively prevented. Therefore, the lifetime of the electron-emitting device can be extended more effectively.

  In the electron-emitting device of the present invention, the thin film electrode may further 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.

  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.

  As already described in the electron-emitting device, the electron-emitting device of the present invention is an electron-emitting device capable of maintaining the electron-emitting characteristics for a long time by avoiding the situation where the thin-film electrode gradually disappears with the emission of electrons. Therefore, an electron emission device configured using such an electron emission element is an electron emission device capable of maintaining electron emission characteristics for a long period of time.

  Further, a self-luminous device constructed using such an electron emission device of the present invention is also included in the scope of the present invention.

  In order to solve the above-described problem, the method for manufacturing an electron-emitting device according to the present invention includes an electron acceleration layer between an electrode substrate and a thin film electrode arranged to face each other. A method of manufacturing an electron-emitting device that emits electrons from the thin-film electrode by accelerating electrons in the electron acceleration layer by applying a voltage therebetween, and includes insulating fine particles on the electrode substrate Forming a fine particle layer, depositing conductive fine particles on the surface of the fine particle layer to form a deposit of conductive fine particles, and forming a thin film electrode on the surface of the electron accelerated layer; And a forming process for forming a conductive path in the electron acceleration layer by applying a DC voltage between the electrode substrate and the thin film electrode in the atmosphere.

  According to the above method, the above-described electron-emitting device of the present invention capable of maintaining the electron emission characteristics for a long period of time can be obtained.

  In the method for manufacturing an electron-emitting device according to the present invention, it is preferable that in the step of forming the electron acceleration layer, conductive fine particle deposits are discretely arranged on the surface of the fine particle layer.

  According to the above method, in addition to the ability to maintain the electron emission characteristics for a long period of time, the electron emission element of the present invention can control the electron emission position in the thin film electrode, the emission amount per unit area, and the like. Can be obtained.

In the method for manufacturing an electron-emitting device according to the present invention, the step of forming the electron acceleration layer includes:
It is preferable that the method further includes a step of applying a basic solution in which an electron donor for donating an electron pair is introduced as a substituent on the entire surface of the electron acceleration layer.

  According to the above method, the electron emission portion can be formed by forming in the atmosphere with good reproducibility, small energy, and mild processing conditions.

  The basic solution has an electron donor that donates an electron pair introduced as a substituent. An electron donating group having an electron donor ionizes after donating an electron (electron pair). The ionized electron donating group transfers charges on the surface of the insulating fine particles, and conducts electricity on the surface of the insulating fine particles. Is considered to be possible. In addition, from the atmospheric condition of the atmosphere, it is considered that the surface adhesion of water molecules or oxygen molecules in the air facilitates this electric conduction phenomenon.

  In the method for manufacturing an electron-emitting device according to the present invention, it is preferable that in the step of performing the forming process, the voltage is applied in a stepwise manner when the DC voltage is applied.

  In forming the electron emission portion by forming, if a voltage that generates a necessary electric field is applied between the electrode substrate and the thin film electrode at once, there is a possibility that the element may cause dielectric breakdown.

  By increasing the voltage stepwise as in the above method, the forming process can be performed without causing dielectric breakdown.

In the method for manufacturing an electron-emitting device according to the present invention, the electric field intensity generated between the electrode substrate and the thin film electrode is 1.9 × 10 ^{7 to} 4.1 × 10 in the forming process. It is preferable to apply a DC voltage so as to be ⁷ [V / m].

This is because when the electric field strength is less than 1.9 × 10 ⁷ [V / m], the forming process cannot be performed, or even when it is formed, the formation of the conductive path is insufficient, and the voltage required for electron emission is applied. This is because the current in the device is not sufficient to obtain electron emission. On the other hand, if the electric field strength exceeds 4.1 × 10 ⁷ [V / m], large-scale dielectric breakdown is likely to occur, and the conductive path itself is destroyed. This is because once such a process is followed, even if a voltage required for electron emission is applied, the current in the device does not flow at all, or even if it flows, it does not have a sufficient amount to obtain electron emission. By setting it as the said range, an electron emission part can be formed by a forming process without a malfunction.

  In the method for manufacturing an electron-emitting device according to the present invention, it is preferable that in the step of forming the electron acceleration layer, deposits of conductive fine particles are discretely arranged on the surface of the fine particle layer using an ink jet method.

  Methods for depositing conductive fine particle deposits in the electron acceleration layer include a spray coating method using a mask and an electrostatic spray method capable of scattering fine droplets without using a mask. By using it, the controllability of the coating position and the reproducibility of the coating amount can be easily secured high.

  The electron-emitting device of the present invention has an electron acceleration layer between an electrode substrate and a thin film electrode arranged to face each other, and a voltage is applied between the electrode substrate and the thin film electrode. An electron-emitting device that emits electrons from the thin film electrode by accelerating electrons in an electron acceleration layer, wherein the electron acceleration layer has a fine particle layer containing insulating fine particles, A single substance or a mixed substance that enhances the flow of electricity in the thickness direction of the fine particle layer is provided, and the electron acceleration layer is a conductive path that passes through the electron acceleration layer in the thickness direction, and the path exit is the In this configuration, a conductive path serving as an electron emission portion for supplying electrons to the thin film electrode is formed in advance.

  In the method for manufacturing an electron-emitting device according to the present invention, an electron acceleration layer is provided between an electrode substrate and a thin film electrode arranged to face each other, and a voltage is applied between the electrode substrate and the thin film electrode. A method of manufacturing an electron-emitting device that emits electrons from the thin film electrode by accelerating electrons in the electron acceleration layer, wherein a fine particle layer containing insulating fine particles is formed on the electrode substrate, and the fine particles A step of forming an electron acceleration layer by depositing conductive fine particles on the surface of the layer to form a deposit of conductive fine particles; a step of forming a thin film electrode on the surface of the electron acceleration layer; and Forming a conductive path in the electron acceleration layer by applying a DC voltage between the electrode substrate and the thin film electrode.

  According to the above configuration or method, it is possible to obtain an electron-emitting device capable of maintaining electron emission characteristics for a long period by avoiding a situation where the thin-film electrode positioned on the electron-emitting side gradually disappears with the emission of electrons. Can do.

It is a schematic diagram which shows the structure of the electron emission apparatus using the electron emission element of one Embodiment of this invention. It is a schematic diagram of the cross section of the electron acceleration layer in the electron emission element with which the electron emission apparatus of FIG. 1 was equipped. 2 is a photograph of a modification of the electron-emitting device provided in the electron-emitting device of FIG. 1, and is a photograph of the surface of the electron acceleration layer in which insulator fine particles are discretely deposited on the fine particle layer in the electron acceleration layer. . It is explanatory drawing which shows the surface state of one deposit in which the electroconductive fine particles of the electron acceleration layer in the electron emission element of the modification shown in FIG. 3 are discretely deposited. It is a schematic diagram of the cross section of the electron acceleration layer in the electron-emitting device of the modification shown in FIG. 3, and is a schematic diagram showing a cross section near one conductive fine particle deposit deposited discretely. (A)-(b) is explanatory drawing which expands and shows the surface state of one deposit in which the electroconductive fine particles are discretely deposited of the electron acceleration layer in the electron emission element of the modification shown in FIG. . It is explanatory drawing which shows the measurement system of the electron emission experiment implemented with respect to an electron emission element. It is a figure which shows the result of having applied the step-wise voltage application in the vacuum with respect to the electron emission element of sample # 1, and measuring the element internal current of an electron emission element. It is a figure which shows the result of having applied the stepwise voltage in atmospheric pressure with respect to the electron emission element of sample # 1, and measuring the element internal current of an electron emission element. It is a figure which shows the result of having measured the element internal current of the electron emission element in a vacuum with respect to the electron emission element of sample # 1 after performing stepwise voltage application (forming process) in atmospheric pressure. For the electron-emitting device created by the same manufacturing method as the electron-emitting device of sample # 1, the final voltage is changed and a forming process is performed, and then the in-device current and electron-emitting current of the electron-emitting device in vacuum are measured. It is a figure which shows the result. (A)-(b) is drawing which shows the state of the silver particle dome surface which is a conductive fine particle deposit, and its vicinity at the time of changing forming process conditions. It is a figure which shows the result of having measured the electron emission current of the electron emission element, after performing the forming process in air | atmosphere with respect to the electron emission element of sample # 7, # 8. It is a figure which shows an example of the self-light-emitting device using the electron emission apparatus of FIG. It is a figure which shows another example of the self-light-emitting device using the electron emission apparatus of FIG. It is a figure which shows another example of the self-light-emitting device using the electron emission apparatus of FIG. 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 FIG.

  Embodiments and examples of an electron-emitting device and an electron-emitting device according to the present invention will be described below 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 a configuration of an electron emission device 10 using an electron emission element 1 according to an embodiment of the present invention.

  As shown in FIG. 1, an electron emission device 10 includes an electron emission element 1 and a power source 7 according to an embodiment of the present invention. The electron-emitting device 1 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 sandwiched therebetween. A voltage is applied between the electrode substrate 2 and the thin film electrode 3 by a power source 7.

  When a voltage is applied between the electrode substrate 2 and the thin film electrode 3, a current flows through the electron acceleration layer 4 between the electrode substrate 2 and the thin film electrode 3, and a part thereof is a strong electric field formed by the applied voltage. Are emitted from the electron acceleration layer 4 as ballistic electrons and emitted from the thin film electrode 3 side to the outside of the device.

  The electrons emitted from the electron acceleration layer 4 pass through (transmit) the thin film electrode 3 or the holes of the thin film electrode 3 caused by the influence of irregularities on the surface of the electron acceleration layer 4 positioned below the thin film electrode 3. It passes through the gap and is released to the outside.

  By the way, as described above, in the configuration in which electrons are emitted from every part of the electron acceleration layer 4 located below the thin film electrode 3, the thin film electrode 3 located on the electron emission side is reverse sputtered by the emitted electrons. As a result, there is a problem that the thin film electrode 3 disappears with time and eventually loses its function as the upper electrode.

  In order to solve such a problem, in the electron-emitting device 1 of the present embodiment, electrons are not emitted from the entire surface of the electron acceleration layer 4, but an electron emission portion is formed in the electron acceleration layer 4, and the electron acceleration layer is formed. In this configuration, electrons are emitted only from the four specific portions.

  That is, the electron acceleration layer 4 has a fine particle layer containing insulating fine particles, and the fine particle layer is provided with a single substance or a mixed substance that enhances the flow of electricity in the thickness direction of the fine particle layer. Further, the electron acceleration layer 4 is preliminarily formed with a conductive path that is a conductive path that passes through the electron acceleration layer 4 in the thickness direction and that serves as an electron emitting portion whose path exit provides electrons to the thin film electrode 3. The formation of the conductive path in advance means that the voltage is applied to the element 1 in a vacuum and before driving, that is, in the manufacturing process of the electron-emitting element 1.

  According to the above configuration, electrons are not emitted from an arbitrary location on the thin film electrode 3 side, but are emitted from an electron emission portion formed in advance in the electron acceleration layer 4 positioned below the thin film electrode 3. The electron emission portion is an exit of a conductive path formed in advance in the electron acceleration layer 4 and passing through the electron acceleration layer 4 in the thickness direction. It is given to the thin film electrode 3 through the path and emitted.

  As described above, in the electron-emitting device 1, instead of being emitted from an arbitrary portion of the electron acceleration layer 4, the emitted portion corresponds to an electron in the electron acceleration layer 4 corresponding to the exit of the conductive path formed in advance. Specific to the discharge part. Therefore, in the thin film electrode 3, the portion reversely sputtered by the emitted electrons is limited to a portion located directly above the electron emitting portion or a portion located in the vicinity of the electron emitting portion, and other portions. Then, the metal material constituting the thin film electrode is not reversely sputtered by the emitted electrons and disappears with time, and the function as the electrode is not lost.

  FIG. 1 shows the electron-emitting device 1 in the case where the single substance or the mixed substance that enhances the ease of electricity flow in the thickness direction of the fine particle layer 105 in the electron acceleration layer 4 is the conductive fine particles 6. The conductive fine particles 6 are deposited on the surface of the fine particle layer 105 to form a deposit 106, and the conductive fine particles 6 are applied to the fine particle layer 105 by depositing the conductive fine particles 6 on the surface of the fine particle layer 105. This is realized by forming 106. The deposit 106 of the conductive fine particles 6 is provided with a physical defect that becomes an electron emission portion in forming a conductive path.

  FIG. 2 is a schematic diagram of a cross section of the electron acceleration layer 4 having a configuration including the deposit 106 of the conductive fine particles 6. As shown in FIG. 2, in the electron acceleration layer 4, the conductive fine particles 6 that form the upper deposit 106 do not mix with the insulating fine particles 5 that form the lower fine particle layer 105. It is deposited on (upper surface). As a method for depositing the conductive fine particles 6 without being mixed with the insulating fine particles 5, the conductive fine particles 6 and the insulating fine particles 5 have the same size, or in the fine particle layer 105, the insulating fine particles 5 are mutually connected. This can be realized by binding using a binder resin. In particular, in the configuration in which the fine particle layer 105 is hardened with a binder resin, the particle size of the insulating fine particles 5 can be selected without considering the mixing of the conductive fine particles 6 into the fine particle layer 105, so that the selection range is widened. Further, there is an advantage that the mechanical strength of the electron-emitting device 1 itself is increased.

  In the deposit 106, an electron emission portion 108 made of physical defects is formed. Although not shown, a conductive path is formed under the electron emission portion 108. Here, the electron emission portion 108 and the conductive path are formed by a forming process in the atmosphere.

  In general, the forming process is a process for forming a conductive path by applying an electric field to an electron-emitting device generally configured in an MIM type, as described in Patent Document 2, for example. The forming process is decisively different from normal dielectric breakdown: a) diffusion of the electrode material into the insulator layer, b) crystallization of the insulator substance, c) formation of a conductive path called a filament, d) insulation This is an accidental growth of a conductive path (current path) explained in various theories such as a stoichiometric shift of a body material.

  The formation of the conductive path (preliminarily formed conductive path) by the forming process in the atmosphere is such that the deposit 106 of the conductive fine particles 6 on the surface of the fine particle layer 105 easily flows electricity in the thickness direction of the fine particle layer 105. By increasing the thickness, it can be easily formed by a forming process in the atmosphere.

  Since the conductive path is formed in advance in the electron acceleration layer 4, a new conductive path is not formed by voltage application to the element required for the subsequent electron emission operation in vacuum, and the current in the element is It flows through a pre-formed conductive path. As a result, the conductive path functions stably during electron emission. On the other hand, applying a voltage in a vacuum to an element in which a conductive path is not formed in advance is a process for forming a conductive path and an electron emission process. That is, electrons are emitted while forming a conductive path. The formation of the conductive path formed under such conditions is not constant, and is newly formed each time a voltage is applied in a vacuum. Therefore, every time a voltage is applied in a vacuum, the conductive state of the element changes, and stable electron emission characteristics cannot be obtained.

  As described above, in the electron-emitting device 1 having the electron acceleration layer 4, the electron emission layer 1 is not emitted from an arbitrary portion of the electron acceleration layer 4 but the emission portion is specified as the electron emission portion of the electron acceleration layer 4. . Therefore, in the thin film electrode 3, the portion reversely sputtered by the emitted electrons is limited to a portion located directly above the electron emitting portion 108 and a portion located near the electron emitting portion 108. For this reason, the portion other than the portion of the thin film electrode 3 positioned directly above or near the electron emitting portion 108 is not exposed to electrons, and the metal material constituting the thin film electrode 3 is reverse sputtered by the emitted electrons, and with time It disappears, and finally the function as an electrode is not lost. As a result, the thin film electrode 3 can maintain a long function as an upper electrode.

  As shown in FIGS. 1 and 2, the conductive fine particles 6 may be a single film-like deposit 106 deposited on the entire surface of the fine particle layer 105. However, as shown in FIG. It is more preferable that the partial deposits 107... 6 are discretely deposited on the surface of the fine particle layer 105. FIG. 3 is a surface photograph of the electron-emitting device 1 in which the conductive fine particles 6 are discretely deposited on the surface of the fine particle layer 105 by the inkjet method. An inner portion surrounded by a black frame is a portion where the thin film electrode 3 is formed. The thin film electrode 3 is uniformly deposited along the unevenness of the deposits 107 shown in black dots.

  The reason why the configuration of the discretely arranged deposits 107 is preferable will be described. In the forming process step in the atmosphere, a current flows from the electrode substrate 2 side to the thin film electrode 3 side aiming at a portion where the current 106 in the deposits 106, 107. Is formed. Therefore, in the single-film deposit 106, the electron emission portion 108 is accidentally determined on the surface of the deposit 106, and the position and the number of the electron-emitting portions 108 are not determined. As described above, when the electron emission portion which is the electron emission portion 108 is accidentally formed on the surface of the electron acceleration layer 4, the electron emission position is controlled or the emission amount per unit area is controlled. I can't.

  The electron emission amount can also be controlled by changing the voltage applied between the electrode substrate 2 and the thin film electrode 3, and the electron emission amount is small at a low voltage, and the electron emission amount is large at a high voltage. Can be operated. However, the device disclosed in this specification has an extremely small amount of electron emission when a low voltage is applied, and the electron emission efficiency is remarkably lowered. For this reason, when it is desired to narrow down the electron emission amount extremely small, the control of the electron emission amount by the applied voltage is not used.

  On the other hand, in the configuration as shown in FIG. 3 in which the conductive fine particles 6 are discretely deposited and the partial deposits 107 are discretely arranged, the conductive path formed by the forming process in the atmosphere is The individual deposits 107 are formed from the electrode substrate 2 side, and the electron emission portions 108 are formed in the individual deposits 107. Therefore, by controlling the arrangement of the deposits 107, the electron emission portion can be arranged at an arbitrary position on the surface of the electron acceleration layer 4, and the electron emission position in the plane of the electron emission element 1 or It is possible to control the discharge amount per unit area. Needless to say, the arrangement of the deposits 107 is not limited to a regular arrangement as shown in FIG. 3 but may be a random arrangement.

  The formation of the discretely arranged deposits 107... Is not limited to the ink jet method using an ink jet head, as long as it is a method that enables the discrete deposition of the conductive fine particles 6. An electrostatic spraying method or the like that can scatter droplets of the conductive fine particles 6 without using a mask can be used. However, in consideration of controllability of the application position and reproducibility of the application amount, application by the ink jet method is preferable.

  FIG. 4 shows a surface photograph of a partial deposit 107. This is formed by the ink jet method, but the partial deposit 107 formed in a dome shape by the ink jet method causes a so-called coffee ring phenomenon in the drying process, and the central portion of the circle is depressed, and the outer peripheral portion Solidify with the ring slightly raised. Note that FIG. 4 is an image of the deposit 107 before the forming process, and thus the electron emission portion 108 is not formed. FIG. 5 is a schematic diagram showing a cross-sectional structure of the deposit 107 solidified in a state where the center of the circle is depressed and the outer ring is slightly raised.

  In the above description, the conductive fine particles 6 have been presented as a single substance or a mixed substance that enhances the ease of electricity flow in the thickness direction of the fine particle layer 105 in the electron acceleration layer 4. However, as another example, an electron pair is provided. A configuration in which a basic dispersant in which an electron donor is introduced as a substituent is imparted to the fine particle layer 105 is also conceivable.

  By applying a basic solution containing a basic dispersant to the fine particle layer 105, the identification represented by the electron donating group contained in the basic solution is applied to the surface of the insulating fine particles 5 constituting the fine particle layer 105. (For example, a phenyl group or a vinyl group which is a π electron system, and an alkyl group, an amino group, or the like). Giving a specific substituent to the surface of the insulating fine particles 5 not only facilitates electric conduction of the particle surface through them, but also the surface of water molecules or oxygen molecules in the atmosphere from atmospheric conditions. Adhesion further facilitates this electrical conduction phenomenon. As a result, like the deposits 106, 107... Of the conductive fine particles 6, a constant conductive path can be formed in the fine particle layer 105 by the forming process in the atmosphere. When a basic solution containing a basic dispersant is applied, it may be applied as a single film or partially as in the case of the conductive fine particles 6. In the case of a basic solution, unlike the conductive fine particles 6, the basic solution does not stay on the surface of the fine particle layer 105 but diffuses into the fine particle layer 105. When the basic solution is discretely applied, there are discrete portions where the basic solution is diffused.

  Examples of commercially available basic dispersants that can be applied to the present invention include various trade names such as trade names manufactured by Avicia: Solsperse 9000, 13240, 13940, 20000, 24000, 24000GR, 24000SC, 26000, 28000, 32550, 34750, and 31845. Solsperse dispersant, trade name manufactured by Big Chemie: Dispersic 106, 112, 116, 142, 161, 162, 163, 164, 165, 166, 181, 182, 183, 184, 185, 191, 2000, 2001, Ajinomoto Product names manufactured by Fine Techno Co., Ltd .: Addisper PB711, PB411, PB111, PB821, PB822, product names manufactured by Fuka Chemicals: EFKA-47, 4050, and the like.

  Further, in the case of a basic solution, it does not stay on the surface of the fine particle layer 105, but is diffused in the fine particle layer 105. Therefore, in the fine particle layer 105 to which the basic solution is applied, a conductive path is formed by an atmospheric forming process. Is not formed as an electron emission portion made of physical defects as formed in the deposits 106, 107... Of the conductive fine particles 6, and only the exit of the conductive path becomes the electron emission portion. Therefore, from the viewpoint of protecting the electron emission portion and realizing long-term driving, it is necessary to harden the electron emission portion like the deposits 106, 107. It is preferable to apply a solid material mixed with a basic solution and form an electron emission portion as an electron emission portion in the solid material deposit like the deposits 106, 107.

  Next, each part in the electron-emitting device 1 will be described in detail. In addition to the function as an electrode, the electrode substrate 2 serves as a support for the electron-emitting device. Therefore, any substrate can be used without particular limitation as long as the substrate has a certain degree of strength, good adhesion to a directly contacting substance, and appropriate conductivity. Specifically, for example, a metal substrate such as SUS, Ti, or Cu, or a semiconductor substrate such as Si, Ge, or GaAs can be used. In addition, a conductive material such as a metal may be attached as an electrode to the surface of an insulating substrate such as a glass substrate or a plastic substrate (interface with the electron acceleration layer 4). The conductive substance to be attached to the surface of the insulating substrate is not particularly limited as long as it has excellent conductivity and can be formed into a thin film using magnetron sputtering or the like. It is preferable to use a conductor having high strength, 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 having a thickness of 200 nm is formed on the surface of a glass substrate and a Cu film having a thickness of 1000 nm may be used may be used because a strong thin film can be formed. However, it is not limited to these materials and numerical values.

  The thin film electrode 3 can be used without particular limitation as long as it can be applied with a voltage. However, from the viewpoint of transmitting electrons that are accelerated and become high energy in the electron acceleration layer 4 without loss of energy as much as possible, it is higher if the material has a low work function and can form a thin film. 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. Above all, gold is free from oxide and sulfide formation reaction because of forming process under atmospheric pressure. 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, and if the film thickness exceeds this, the emission of ballistic electrons is extremely reduced. The decrease in the amount of ballistic electrons emitted is thought to be due to recapture of the ballistic electrons in the electron acceleration layer 4 by absorption or reflection of the ballistic electrons.

As materials for the insulator fine particles 5 included in the fine particle layer 105 in the electron acceleration layer 4, materials such as SiO ₂ , Al ₂ O ₃ , and TiO ₂ become 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. Further, as the insulating fine particles 5, fine particles made of an organic polymer may be used.

  Further, as the insulating fine particles 5, two or more kinds of particles having different materials may be used, particles having different particle size peaks may be used, and a single particle may have a broad particle size. A distribution may be used. However, as described above, the conductive fine particles 6 are deposited on the fine particle layer 105 to form the deposits 106, 107. At the interface between the deposits 106, 107... And the fine particle layer 105, the two layers need to be separated even if there is little mutual mixing. Therefore, it is necessary to select the particle diameter of the insulating fine particles 5 according to the particle diameter of the conductive fine particles 6 so that mixing does not occur. However, when the binder resin that binds the insulating fine particles 5 to each other is used, the binder resin prevents the conductive fine particles 6 from entering, so that the particle diameter of the insulating fine particles 5 is smaller than when the binder resin is not used. Some margin can be expected.

  Further, the layer thickness of the fine particle layer 105 preferably has a thickness sufficient to absorb the solvent used when the conductive fine particles 6 are applied and diffuse it into the fine particle layer 105. Although this will be described in detail later, for the purpose of suitable manufacturing, a step of applying a basic solution to the entire surface of the electron acceleration layer 4 in which the conductive fine particles 6 are deposited on the fine particle layer 105 is added. It is. When the basic solution is applied in a state where the deposits 106, 107... In the electron acceleration layer 4 are not completely solidified, the conductive fine particles 6 constituting the deposits 106, 107. End up. Therefore, the deposits 106, 107... Need to be completely solidified when applying the basic solution. In order to completely solidify the deposits 106, 107..., It is necessary to absorb and diffuse the solvent used when applying the conductive fine particles 6 in the fine particle layer 105. Therefore, it is necessary that the fine particle layer 105 has a void enough to absorb the solvent and has a layer thickness sufficient to absorb and diffuse the solvent. This also applies to the case where a basic solution containing a basic dispersant is used as the single substance or the mixed substance for increasing the ease of electricity flow in the thickness direction of the fine particle layer, and a solid substance is mixed therewith. On the other hand, as the material of the conductive fine particles 6 constituting the deposits 106, 107..., Any conductor can be used on the principle of operation of generating ballistic electrons. When the conductor has a high anti-oxidation power, oxidative deterioration of the conductive fine particles 6 can be avoided, and a long life can be achieved. 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. Examples of the conductor having a high antioxidation 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 particle size of the conductive fine particles 6 needs to be a particle size such that the deposits 106, 107,... Are not easily destroyed by electron beam irradiation, especially by reverse sputtering. Then, it has been confirmed that the reverse sputtering phenomenon can be prevented. The point which is the deposit | attachment of the electroconductive fine particles 6 of such a magnitude | size (mass) suppresses own destruction by an emitted electron.

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

  The binder resin used for the fine particle layer 105 is required to have good adhesion to the electrode substrate 2, disperse the insulating fine particles 5, and have insulation properties. As described above, the fine particle layer 105 needs not to prevent the fine particle layer 105 from absorbing the solvent used when the conductive fine particles 6 are applied. It is necessary not to prevent the absorption and diffusion of the solvent used when applying the coating.

  Examples of the binder resin 15 include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltriethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, hydrolyzable group-containing siloxane, Vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxy Propyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysila N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-tri Ethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropyltri Examples include methoxysilane, bis (triethoxysilylpropyl) tetrasulfide, and 3-isocyanatopropyltriethoxysilane. These resin binders can be used alone or in combination of two or more.

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

  First, the dispersing agent and the insulating fine particles 5 are put into a dispersion solvent, and the insulating fine particles 5 are dispersed by applying an ultrasonic dispersing device to obtain the insulating fine particle dispersion solution A. The dispersion method is not particularly limited, and the dispersion method may be performed by a method other than the ultrasonic disperser. As a dispersion solvent for dispersing the insulating fine particles 5, any insulating solvent that can effectively disperse the insulating fine particles 5 and evaporate after coating can be used without particular limitation. For example, toluene, benzene, xylene, hexane, tetradecane, or the like can be used. Any dispersant may be used as long as it is compatible with the dispersion solvent and can disperse the insulating fine particles 5.

  Next, the insulating fine particle dispersion solution A prepared as described above is applied onto the electrode substrate 2 to form the fine particle layer 105 constituting the electron acceleration layer 4. As a coating method, for example, a spin coating method can be used. The insulating fine particle dispersion solution A is dropped on the electrode substrate 2, and a thin film to be the fine particle layer 105 is formed by using a spin coating method. A predetermined film thickness can be obtained by repeating the dropping of the insulating fine particle dispersion solution A onto the electrode substrate 2, film formation by spin coating, and drying a plurality of times. In addition to the spin coating method, for example, a dropping method, a spray coating method, or the like can be used for forming the fine particle layer 105.

  Next, a dispersing agent and the conductive fine particles 6 are added to a dispersion solvent, and the conductive fine particles 6 are dispersed by applying an ultrasonic dispersing device to obtain a conductive fine particle dispersion solution B. The dispersion method is not particularly limited, and the dispersion method may be performed by a method other than the ultrasonic disperser. As a dispersion solvent for dispersing the conductive fine particles 6, any conductive solvent can be used without particular limitation as long as the conductive fine particles 6 can be effectively dispersed and evaporated after coating. For example, toluene, benzene, xylene, hexane, tetradecane, or the like can be used. Any dispersant may be used as long as it has good compatibility with the dispersion solvent and can disperse the conductive fine particles 6.

  As the conductive fine particle dispersion solution B, a conductive fine particle dispersion solution in which the conductive fine particles 6 are previously dispersed in a dispersion solvent may be used. However, since the coating solution has a clay limitation depending on the coating method, a commercially available conductive fine particle dispersion solution may be used within the limitation.

  The conductive fine particle dispersion solution B is applied to the surface of the fine particle layer 105, and the conductive fine particles 6 are deposited on the surface of the fine particle layer 105 to form deposits 106, 107. As a coating method, a spin coating method, an inkjet method, a droplet dropping method, a spraying method, or the like can be used. In addition, when the conductive fine particles 6 are discretely deposited to form the deposits 107, the ink jet method is most preferable. However, a spray coating method using a mask or a droplet of the conductive fine particles 6 can be scattered without using a mask. An electrostatic spray method or the like may be used.

  When the electron acceleration layer 4 composed of the fine particle layer 105 and the deposits 106, 107... Formed thereon is formed, 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 can be used. In addition to the magnetron sputtering method, for example, an inkjet method, a spin coating method, a vapor deposition method, or the like can be used for forming the thin film electrode 3.

  Next, in the air, a DC voltage is applied between the electrode substrate 2 and the thin film electrode 3 to physically destroy the deposits 106, 107... To form a conductive path. As a result, electron emission portions 108 are formed in the deposits 106, 107..., And a conductive path is formed in the fine particle layer 105. In performing the forming process, it is preferable that the DC voltage applied between the electrode substrate 2 and the thin film electrode 3 is increased stepwise. This is because if a voltage that generates a required electric field is applied between the electrode substrate 2 and the thin film electrode 3 at once, the element may break down. By increasing the voltage stepwise, processing can be performed without causing dielectric breakdown.

In the forming process, the voltage applied between the electrode substrate 2 and the thin film electrode 3 has an electric field strength generated between the electrode substrate 2 and the thin film electrode 3 of 1.9 × 10 ^{7 to} 4.1 ×. It is preferable to set to 10 ⁷ [V / m]. This is because if the electric field strength is less than 1.9 × 10 ⁷ [V / m], the forming process cannot be performed, or even if it can, the formation of the conductive path is insufficient and the voltage required for electron emission is applied. However, the current in the device is not sufficient to obtain electron emission. On the other hand, if the electric field strength exceeds 4.1 × 10 ⁷ [V / m], large-scale dielectric breakdown is likely to occur, and the conductive path itself is destroyed. Once such a process is followed, even if a voltage required for electron emission is applied, the current in the device does not flow at all, or even if it flows, the amount is not sufficient to obtain electron emission.

  In manufacturing the electron-emitting device 1 of the present invention, more preferably, the fine particle layer in the electron acceleration layer 4 is formed on the entire surface of the electron acceleration layer 4 in which the deposits 106, 107... Are formed on the fine particle layer 105. Applying a basic solution containing the basic dispersant described above as a single substance or a mixed substance other than the conductive fine particles 6 to enhance the flow of electricity in the thickness direction of 105, and then forming the thin film electrode 3 It is.

  The deposits 106, 107, etc. are those in which the conductive fine particles 6 are deposited on the fine particle layer 105, and the density of the conductive fine particles 6 is high. On the other hand, in the fine particle layer 105, although a part of the conductive fine particles 6 may permeate near the interface, the existence ratio is extremely low. Therefore, in such an electron acceleration layer 4, it is not easy to form a conductive path even if a DC voltage is applied in the forming process.

  However, by applying the basic solution to the electron acceleration layer 4 as described above, the electron emission portion 108 is formed in the forming process step with good reproducibility, small energy, and mild process conditions. It has been confirmed that a conductive path can be formed.

  By applying a basic solution to the fine particle layer 105 having the deposits 106, 107... On the surface, as described above, the electric conduction on the particle surface is facilitated and the atmospheric conditions such as the atmospheric air The surface adhesion of water molecules or oxygen molecules further facilitates this electric conduction phenomenon. As a result, the forming process can be performed easily and reliably.

  Here, the application method of the basic solution is a method that can uniformly coat a very small amount of solution without damaging the electron acceleration layer 4 on which the deposits 106, 107... On the surface of the fine particle layer 105 are disposed. Often, a spin coating method, a dropping method or the like can be used.

  Moreover, although it is a procedure which apply | coats a basic solution, it is also possible to apply | coat to the fine particle layer 105 before forming the deposits 106,107 ....

  However, the applicant of the present application believes that the procedure of applying the basic solution after forming the deposits 106, 107... Facilitates the formation of the conductive path in the forming process.

  This is due to the following reason. 6A to 6C are photographs of the surface of the deposit 107 in which the conductive fine particles 6 are discretely arranged. Among these, Fig.6 (a) shows the surface state of the deposit 107 before basic solution application | coating (before forming process). A black line that goes around the edge can be seen at the edge. FIG. 6B is a photograph of the surface state of the deposit 107 immediately after the application of the basic solution (before the forming process), focusing on the edge. As can be seen from a comparison with FIG. 6A, it can be seen that a second black line is formed around the edge part. FIG. 6C is a photograph of the surface state of the deposit 107 immediately after application of the basic solution (before the forming process), focusing on the ring part that is most prominent. As can be seen from comparison with FIG. 6 (a), it can be confirmed that a part of the most swelled ring is damaged, and a blue substance pool can be confirmed in the central recess.

  As a result of such observation, the applicant of the present application can scratch the surface of the deposits 106, 107, etc. by applying the basic solution after the deposits 106, 107,. In the forming process, it is considered that an electric current flows aiming at the scratch on the surface, and as a result, formation of a conductive path is facilitated.

[Example 1]
In a 10 mL reagent bottle, 2.0 g of ethanol solvent and 0.5 g of tetramethoxysilane KBM-04 (manufactured by Shin-Etsu Chemical Co., Ltd.) are placed. 0.5 g of company manufactured) was added, and the reagent bottle was put on an ultrasonic disperser to obtain an insulating fine particle dispersion solution A.

  After the above-mentioned insulator fine particle dispersion solution A is dropped on a 25 mm square glass substrate having an ITO thin film as the electrode substrate 2 on the surface, the silica as the fine particle layer 105 is used at 8000 rpm for 10 s using a spin coating method. A particle layer was formed and dried at room temperature for several hours.

Next, a tetradecane dispersion solution in which silver nanoparticles as conductive fine particles 6 are dispersed on the surface of the silica particle layer (manufactured by ULVAC, Inc., average particle diameter of silver fine particles: 5.0 nm, solid concentration of silver fine particles: 54%) Were ejected discretely using a so-called inkjet head, and a silver particle dome as a droplet mark of silver nanoparticles was formed as a deposit 107 at a landing diameter of 26 μm and a density of about 5500 particles / cm ² . . At this time, the discharge condition of the inkjet head is a discharge volume of 4 pL and a discharge pitch of one drop per 135 μm square.

  Next, 3 mL of a toluene solvent is placed in a 10 mL reagent bottle, 0.03 g of Ajisper PB821 (manufactured by Ajinomoto Fine Techno Co., Ltd.), which is a basic dispersant (basic functional group-containing copolymer), is added, and ultrasonic dispersion is performed. A basic solution was obtained by dispersing in a vessel. This basic solution was dropped onto a silica particle layer having a large number of silver particle domes, and then applied under conditions of 1000 rpm and 10 s using a spin coating method.

Finally, a surface electrode as a thin film electrode 3 was formed on the surface of a silica particle layer having a large number of silver particle domes using a magnetron sputtering apparatus, thereby obtaining an electron-emitting device 1 of sump # 1. Gold was used as the film forming material for the surface electrode, the layer thickness of the surface electrode was 40 nm, and the area was 0.014 cm ² .

  With respect to the electron-emitting device 1 of Sample # 1, electron emission experiments were performed in a vacuum and in the atmosphere using the measurement system shown in FIG.

First, FIG. 7 shows a measurement system used in the electron emission experiment. In the measurement system of FIG. 7, the counter electrode 8 is disposed on the thin-film electrode 3 side of the electron-emitting device 1 with an insulator spacer 9 (diameter: 1 mm) interposed therebetween. A voltage V1 is applied between the electrode substrate 2 and the thin film electrode 3 of the electron-emitting device 1 of sample # 1 by the power source 7A, and a voltage V2 is applied to the counter electrode 8 by the power source 7B. ing. In-device current (in-device current density) I1 per unit area flowing between the thin film electrode 3 and the power source 7A was measured by placing the above measurement system in a vacuum of 1 × 10 ⁻⁸ ATM and in the atmosphere. .

FIG. 8 shows the current I1 in the device when a DC voltage is applied to the electron-emitting device 1 of sample # 1 from 0 to +19 V in a 0.1 V step (increases in steps of 0.1 V) in a vacuum. The measurement results are shown. As can be seen from FIG. 8, the in-device current I1 was 1 × 10 ⁻⁷ A / cm ² or less in the entire range from 0 to + 19V. The electron-emitting device having the in-device current I1 in this state is almost an insulator, and the electron-emitting device 1 of sample # 1 did not have a function as an electron-emitting device.

  FIG. 9 shows the current I1 in the device when a DC voltage is applied to the electron-emitting device 1 of sample # 1 from 0 to +19 V in 0.1 V steps (increments in steps of 0.1 V) in the air. The measurement results are shown. Here, the voltage increase rate was 1 V / 3 seconds. Moreover, the voltage application process in the atmosphere was performed only once.

  As shown in FIG. 9, the device current flows several hundred times or more compared with that in the vacuum immediately after the voltage application, but it shows a non-linear and rapid current increase characteristic especially from around + 9V. After a sudden increase in current, the change in current value decreases with increasing voltage, and the current value is saturated near the final value of + 18.5V.

  While such a current flows, a light emission phenomenon that can be visually discerned occurs on the silver particle dome on the element surface. In exchange for this phenomenon, a part of the dome is chipped or cracked. Since the defect generated in the silver particle dome becomes a conductive path when a voltage is applied next, the voltage application process in the atmosphere applies an electric field to an electron-emitting device configured in a general MIM type. In addition, it is considered that a conductive path formation mechanism similar to the so-called “forming process” for forming a conductive path is developed. Hereinafter, this conductive path forming process is referred to as atmospheric forming process.

Next, the electron-emitting device of sample # 1 subjected to such an atmospheric forming process was placed in a vacuum (1 × 10 ⁻⁸ ATM) in FIG. 7 to examine electron emission characteristics. Here, the in-device current I1 and the electron emission current I2 per unit area were measured. As the electron emission current I2, a current I2 flowing between the counter electrode 8 and the power source 7B was measured.

The results are shown in FIG. An electron emission of 4.02 × 10 ⁻⁴ [A / cm ² ] per unit area was obtained at an applied voltage of 19.8 V to the thin film electrode 3. Since the electron emission portion is limited to the silver particle dome portion, the electron emission density per silver particle dome of this embodiment is 1.38 × 10 ⁻² [A / cm ² ].
[Example 2]
As Example 2, an electron-emitting device 1 of Sample # 2 was prepared in the same procedure as in Example 1 except that a basic solution was not applied to a silica particle layer having many silver particle domes. In Example 2, chipping and cracking could be formed in the silver particle dome by forming in air, and electron emission in vacuum could be confirmed. However, the current flowing in the element cannot be controlled, and it is difficult to control the degree of chipping or cracking formed in the silver particle dome.
[Example 3]
Next, the result of investigating the relationship between the applied voltage value and the electron emission characteristics of the atmospheric forming process is shown. The element preparation conditions are the same as those of the electron-emitting element 1 of sample # 1 in Example 1, but for comparison, the final value of the applied voltage in the atmospheric forming was changed to 17V, 19V, 25V, 30V, and 40V.

  In the silver particle dome immediately after forming in the atmosphere, chipping and cracking occurred only in the silver particle dome in the voltage application range of 19V and 25V, but in the voltage application range of 30V and 40V in the final value, The dome was lost, leaving only its trace on the surface of the silica particle layer, and at the same time, the silica particle layer and the surface electrode near the silver particle dome were destroyed and scattered. On the other hand, no particular change was observed in the voltage application range where the final value was 17V.

The electron emission characteristics of the device obtained in Example 3 are shown in FIG. FIG. 11 shows the current density in the device and the electron emission current density per unit area (both values when +20 V is applied) with respect to the applied voltage in the atmospheric forming process in vacuum (1 × 10 ⁻⁸ ATM). . Except for the result of 17 V, it can be seen that the current in the device decreases as the applied voltage in the atmospheric forming process increases, and the amount of electron emission decreases accordingly.

  Moreover, the state of the silver particle dome in the case where final values are 17V, 19V, and 30V, respectively, is shown in FIGS. 12 (a) to 12 (c). The conductive path formed in the element is concentrated on the portion where the silver nanoparticles are deposited (silver particle dome). Therefore, as shown in FIG. 5C, it is expected that the formation of the current path becomes difficult when the silver particle dome is significantly destroyed by the atmospheric forming process. On the other hand, as shown in FIG. 5C, a current path that allows a current in the element to sufficiently flow cannot be formed with a processing voltage that does not give any external change to the silver particle dome. On the other hand, as shown in FIG. 5B, a good result was obtained when a defect occurred in a portion (silver particle dome) where silver nanoparticles were appropriately deposited.

From the results of Example 1 and Example 3, the conditions of the applied voltage for atmospheric forming are 18.5 or more and less than 30V, more preferably 18.5V or more and less than 25V, and only the silver particle dome is chipped or cracked. It is judged that it is good to generate.
[Example 4]
Electron emission of sample # 3 is the same as sample # 1, except that a tetradecane dispersion solution in which silver nanoparticles are dispersed by ink jet is densely discharged to form a deposit of silver nanoparticles on the surface of the silica particle layer. An element was formed. The discharge conditions at this time are a discharge volume of 4 pL and a discharge pitch of 62 μm. By doing in this way, the discharge dispersion solvent connected with the adjacent tetradecane dispersion solvent, and became planar.

The electron-emitting device 1 of Sample # 3 thus prepared was subjected to a forming process in the atmosphere under the same conditions as in Example 1, and then a DC voltage (+18 V) was applied in a vacuum of 1 × 10 ⁻⁸ ATM. FIG. 13 shows the result of continuous driving of the element. FIG. 13 also shows the result of continuous driving of the electron-emitting device in which the forming process in the atmosphere is performed on the sample # 1 of Example 1.

  As is apparent from FIG. 13, the planar element showed an abnormal increase in electron emission after 15 minutes, and immediately after that, the electron emission stopped. This is because, in a planar device, an abnormal increase in the electron emission portion occurs in the aging process from the limited electron emission portion formed in the initial stage, the device cannot withstand the increase in the current in the device, and the device is destroyed. It is thought to have occurred. Also from this result, it can be seen that a configuration in which the partial deposits 107 are arranged discretely is more preferable for maintaining the electron emission characteristics for a long period of time.

[Embodiment 2]
14-16, the self-light-emitting device which comprised the self-light-emitting device in the electron emission apparatus 10 using the electron-emitting device 1 of one Embodiment based on this invention demonstrated in Embodiment 1 was demonstrated. Respectively.

  A self-luminous device 31 shown in FIG. 14 includes a light-emitting unit 36 in addition to the electron-emitting device 10 including the electron-emitting device 1 and a power supply 7 that applies a voltage to the electron-emitting device 1. The light emitting unit 36 has a structure in which an ITO film 33 and a phosphor 32 are laminated on a glass substrate 34 serving as a base material. The light emitting unit 36 is disposed at a distance from the position facing the electron-emitting device 1. The self light emitting device 31 is vacuum sealed.

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, (Y, Gd) BO ₃ : Eu in red, Zn ₂ SiO ₄ : Mn, BaAl ₁₂ O ₁₉ : Mn in green, and BaMgAl ₁₀ O ₁₇ : Eu ²⁺ in blue can be used. It is. The phosphor 32 is formed on the surface of the glass substrate 34 on which the ITO film 33 is formed, and preferably has a thickness of about 1 μm. The thickness of the ITO film 33 is 150 nm in the present embodiment, as long as it is a film thickness that 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 emission luminance of the phosphor 32, it is necessary to accelerate the electrons emitted from the electron-emitting device 1 toward the phosphor 32. In order to realize such acceleration, as shown in FIG. 14, a power source 35 is provided between the electrode substrate 2 of the electron-emitting device 1 and the ITO film 33 of the light emitting unit 36 to form an electric field for accelerating electrons. A configuration that allows voltage application to be applied is preferable. 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-light-emitting device 31 ′ shown in FIG. 15 includes a phosphor (light-emitting body) 32 in addition to the electron-emitting device 10 including the electron-emitting device 1 and a power source 7 that applies a voltage to the element. In the self-luminous device 31 ′, the phosphor 32 has a planar shape and is disposed on the surface of the electron-emitting device 1. Here, the phosphor 32 layer formed on the surface of the electron-emitting device 1 is prepared as a coating liquid composed of a kneaded material with the phosphor particles finely divided as described above, and is formed on the surface of the electron-emitting device 1. To do. However, since the electron-emitting device 1 itself has a structure that is weak against external force, there is a risk that the device may be damaged if film forming means by the bar coater method is used. Therefore, a method such as a dropping method or a spin coating method may be used.

  A self-luminous device 31 ″ shown in FIG. 16 includes a phosphor (light emitter) in the electron acceleration layer 4 of the electron emitter 1 in addition to the electron emitter 10 including the electron emitter 1 and a power source 7 for applying a voltage thereto. ) Fluorescent fine particles are mixed in as 32 '. In this case, the fine particles of the phosphor 32' may also be used as the insulating fine particles 5. However, the aforementioned phosphor fine particles generally have low electric resistance, The electrical resistance is clearly lower than that of the insulating fine particles 5. Therefore, when the fluorescent fine particles are changed to the insulating fine particles 5 and mixed, the mixing amount of the fluorescent fine particles must be kept small. When spherical silica particles (average diameter 110 nm) are used as the insulating fine particles 5 and ZnS: Mg (average diameter 500 nm) is used as the phosphor fine particles, a weight mixing ratio of about 3: 1 is appropriate.

  In the self-luminous devices 31, 31 ′, 31 ″, the electrons emitted from the electron-emitting device 1 collide with the phosphors 32, 32 to emit light. Since the electron-emitting device 1 has an improved electron emission amount, The self-light-emitting devices 31, 31 ′, 31 ″ can emit light effectively.

Further, FIG. 17 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. 17 includes the self-luminous device 31 ″ shown in FIG. 16 and a liquid crystal panel 330. In the image display device 140, the self-luminous 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. 14 is used as the image display apparatus 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.

  The electron-emitting device according to the present invention can ensure electrical continuity, flow a sufficient current in the device, and emit ballistic electrons from the thin film electrode. Therefore, for example, it can be suitably applied to an image display device or the like by combining with a light emitter.

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)
7A power source 7B power source 8 counter electrode 9 insulator spacer 10 electron emission device 31, 31 ', 31 "self-emitting device 32, 32' phosphor (luminescent material)
33 ITO film 34 Glass substrate 35 Power supply 36 Light emitting part 105 Fine particle layer 106 Deposit 107 Deposit 140 Image display device 330 Liquid crystal panel

Claims (16)

An electron acceleration layer is provided between the electrode substrate and the thin film electrode arranged opposite to each other, and a voltage is applied between the electrode substrate and the thin film electrode to accelerate electrons in the electron acceleration layer. An electron-emitting device that emits the electrons from the thin film electrode,
The electron acceleration layer has a fine particle layer containing insulating fine particles, and the fine particle layer is provided with a single substance or a mixed substance that enhances the flow of electricity in the thickness direction of the fine particle layer,
In the electron acceleration layer, a conductive path that passes through the electron acceleration layer in the thickness direction and that serves as an electron emission portion whose path exit gives the electrons to the thin film electrode is formed in advance. An electron-emitting device.   The said single substance or mixed substance is provided so that the provision position when it sees from the upper surface of the said fine particle layer by making the electrode substrate side in the said fine particle layer into a lower surface may become discrete. Electron-emitting devices. The single substance or mixed substance is conductive fine particles,
The conductive fine particles are deposited on the surface of the fine particle layer to form a deposit,
The electron-emitting device according to claim 1, wherein the deposit of the conductive fine particles is provided with a physical defect serving as the electron-emitting portion.   The electron-emitting device according to claim 1, wherein the fine particle layer further includes a binder resin that binds the insulating fine particles to each other.   The electron-emitting device according to claim 3, wherein the conductive fine particles are a noble metal.   The electron-emitting device according to claim 3, wherein the conductive fine particles include at least one of gold, silver, platinum, palladium, and nickel.   7. The electron-emitting device according to claim 1, 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 1 to 7, and a power supply unit that applies a voltage between the electrode substrate and the thin-film electrode in the electron-emitting device. Electron emission device.   A self-luminous device comprising the electron-emitting device according to claim 8 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 9. An electron acceleration layer is provided between the electrode substrate and the thin film electrode arranged opposite to each other, and a voltage is applied between the electrode substrate and the thin film electrode to accelerate electrons in the electron acceleration layer. A method of manufacturing an electron-emitting device that emits the electrons from the thin-film electrode,
Forming a fine particle layer containing insulating fine particles on the electrode substrate, and depositing conductive fine particles on the surface of the fine particle layer to form a deposit of conductive fine particles, thereby forming an electron acceleration layer;
Forming a thin film electrode on the surface of the electron acceleration layer;
And a forming process for forming a conductive path in the electron acceleration layer by applying a DC voltage between the electrode substrate and the thin film electrode in the atmosphere.   12. The method of manufacturing an electron-emitting device according to claim 11, wherein, in the step of forming the electron acceleration layer, conductive fine particle deposits are discretely arranged on the surface of the fine particle layer. In the step of forming the electron acceleration layer,
The electron according to claim 11 or 12, further comprising a step of applying a basic solution in which an electron donor for donating an electron pair is introduced as a substituent on the entire surface of the electron acceleration layer. A method for manufacturing an emitter.   14. The method of manufacturing an electron-emitting device according to claim 11, wherein, in the step of performing the forming process, the voltage is applied in a stepwise manner when a DC voltage is applied. In the step of forming, the direct current voltage is applied so that the electric field strength generated between the electrode substrate and the thin film electrode is 1.9 × 10 ^{7 to} 4.1 × 10 ⁷ [V / m]. The method of manufacturing an electron-emitting device according to claim 11, wherein the electron-emitting device is applied.   16. The method according to claim 11, wherein, in the step of forming the electron acceleration layer, deposits of conductive fine particles are discretely arranged on a surface of the fine particle layer using an inkjet method. A method for manufacturing an electron-emitting device.