JP2010262857A - Manufacturing method of electron-emitting element, and forming method and lighting apparatus of surface-emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the manufacturing method of an electron-emitting element having an emitter with uniform electron-emitting sources and superior reliability. <P>SOLUTION: The manufacturing method of the electron-emitting element has a step of constituting a catalytic-containing film 102, containing a catalytic material to advance constitution of a graphite structure on a substrate 21 and forming a carbon structure 104, in a direction normal to the substrate 21 so as to be appropriately dispersed on the catalytic-containing film 102. The carbon structure 104 is changed to the graphite structure to constitute a carbon nanotube 101, by heating the substrate 21 to move a catalytic particle 105 within the carbon structure 104. Accordingly, the electron-emitting element is manufactured with an emitter 23, constituted from the carbon nanotube 101, oriented substantially in a direction normal to the substrate 21 and disposed at an even density. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an electron-emitting device using carbon nanotubes as an emitter, a method for forming a planar light-emitting device including the electron-emitting device, and an illumination device including the electron-emitting device.

  Since the field emission light-emitting element is flat emission and the element itself is thin, an illuminating device using the field emission light-emitting element as an illumination light source can be installed without limiting a place such as a ceiling or a wall surface. Therefore, the field emission light-emitting element can be expected as an illumination light source that replaces a fluorescent lamp or the like. A field emission type electron-emitting device composed of fibrous carbon such as a carbon nanotube is used as an electron source for emitting light from an illuminator of an anode substrate in an illumination device or a fluorescent display tube using electron emission characteristics. There is something. This electron-emitting device is manufactured by applying a paste in which fibrous carbon is dispersed in a solvent to a cathode substrate. However, since the fibrous carbon applied by a normal method is not oriented in the direction in which electrons are emitted, that is, in the direction perpendicular to the substrate, electrons cannot be emitted efficiently.

  In order to orient the carbon nanotubes in a direction perpendicular to the substrate, an adhesive tape is applied to the surface of the applied carbon film, and then the adhesive tape is removed to orient the carbon fibers perpendicularly to the substrate (raising). Known (Patent Document 1). Also, there is a method of increasing the starting point of electron emission by applying a reverse bias in a reduced-pressure atmosphere into which an activation gas is introduced to roughen the surface on which the carbon nanotube is applied to expose and raise the carbon nanotube (Patent Document 2). Proposed.

In addition, it has been reported that the electric field concentrates favorably at the tip of the carbon nanotube by setting the density of the raised carbon nanotube to 10 ¹⁰ / cm ² or less (Non-patent Document 1). Therefore, it is desirable that the raised carbon nanotubes are appropriately dispersed, and several methods have been proposed for specifying the place where the carbon nanotubes are grown (Patent Documents 3, 4, and 5).

  As a method for producing carbon nanotubes, a method using graphitization of amorphous carbon by solid-phase reaction using a catalytic metal has been proposed (Patent Document 6).

Japanese Patent No. 3468723 JP 2008-097842 A Japanese Patent No. 3502804 Japanese Patent No. 3581298 JP 2004-259667 A International Publication No. 2005/033006

H. Shimoyama et al., Proceedings of SPIE, Vol. 4510 (2001), pp. 163-171.

  The method using the adhesive tape disclosed in Patent Document 1 has a problem in the uniformity of electron emission because the number of electron emission starting points and the density thereof cannot be controlled. Further, the method disclosed in Patent Document 2 has a problem in the reliability of the electron-emitting device because the carbon nanotube is damaged by ion irradiation.

  In addition, the method disclosed in Patent Document 3 includes a process of creating a projection that is a nanotube generation site, a process of creating a mask, a process of attaching a catalyst, a process of growing a nanotube, and a process of removing the mask. Therefore, there is a problem that the process becomes complicated.

  Furthermore, in the method disclosed in Patent Document 4, since electrophoresis is used when attaching carbon nanotubes to a desired position on the anodized film, it is difficult to control the degree of adhesion. is there. In the method disclosed in Patent Document 5, in order to attach the carbon nanotube at a desired position, the carbon nanotube including the magnetic substance is oriented using a magnetic field and fixed with a low melting point metal. Similar to the method disclosed in the above, there is a problem in its controllability.

  In addition, a light emitting element including an electron emission electrode with a low density of electron emission starting points and a low reliability has a problem that light emission is uneven and luminance is low.

  The present invention has been made in view of such a problem, and provides a method for manufacturing an electron-emitting device having an emitter with a substantially uniform number and density of electron emission starting points and excellent in reliability. Objective. Furthermore, an object of the present invention is to provide a method for forming a planar light emitting element that emits light substantially uniformly and with good luminance, and an illumination device.

In order to achieve the above object, a method for manufacturing an electron-emitting device according to the first aspect of the present invention includes:
A method of manufacturing an electron-emitting device that emits electrons from an emitter composed of carbon nanotubes,
Forming a catalyst-containing film containing a catalyst for promoting carbon nanotube formation on a substrate;
Forming a substantially vertically oriented carbon structure on the catalyst-containing film;
The catalyst in the catalyst-containing film is moved into the carbon structure to form a carbon nanotube, thereby forming the emitter composed of the carbon nanotubes oriented substantially perpendicular to the substrate. Process,
It is characterized by providing.

In order to achieve the above object, a method for forming a planar light emitting device according to the second aspect of the present invention includes:
Disposing a phosphor layer facing the electron-emitting device manufactured by the manufacturing method;
Disposing an anode electrode facing the electron-emitting device across the phosphor layer;
It is characterized by providing.

  In order to achieve the above object, an illumination device according to a third aspect of the present invention includes the electron-emitting device manufactured by the manufacturing method.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the electron emission element provided with the emitter with the substantially uniform number and density of the electron emission, and excellent in reliability can be provided. Furthermore, it is possible to provide a method for forming a planar light emitting element that emits light substantially uniformly and with good luminance, and a lighting device.

1 is a cross-sectional view of a field emission light-emitting device according to a first embodiment of the present invention. It is a disassembled perspective view of the field emission light emitting element shown in FIG. It is sectional drawing which shows typically the emitter area | region of the field emission light emitting element shown in FIG. It is a figure which shows the manufacturing method of the field emission light emitting element which concerns on the 1st Embodiment of this invention. It is a figure which shows the manufacturing method of the field emission light emitting element which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows typically a part of field emission display which applied the field emission light emitting element shown in FIG.

  Next, a manufacturing method of the field emission light emitting device (planar light emitting device) 1 according to the embodiment of the present invention will be described in detail with reference to the drawings.

(First embodiment)
First, the field emission light-emitting device 1 manufactured by the manufacturing method according to the first embodiment of the present invention will be described.

  As shown in FIGS. 1 and 2, the field emission light-emitting device 1 includes an anode substrate 10, a cathode substrate 20, and a spacer 30.

  The anode substrate 10 includes a substrate 11, an anode electrode 12 formed on the surface thereof, and a phosphor layer 13 formed on the anode electrode 12.

  The substrate 11 is made of an insulating transparent material such as soda lime glass or borosilicate glass, crystal or quartz. However, other materials may be used as long as the material can be insulated.

The anode electrode 12 is a transparent electrode composed of indium tin oxide (ITO), zinc oxide (ZnO), titanium oxide (TiO ₂ ), carbon nanotube (CNT), carbon nanohorn (CNH), or the like.

  The phosphor layer 13 is composed of an electron beam excited phosphor that emits fluorescence when irradiated with an electron beam, and has a film thickness of, for example, 0.1 μm to 100 μm. The electron beam excited phosphor is composed of, for example, a sulfide phosphor, an oxide phosphor, and a nitride phosphor.

  The cathode substrate 20 includes a substrate 21, a cathode electrode 22 formed on the surface thereof, and an emitter 23 formed on the cathode electrode 22.

  The substrate 21 is made of an insulating transparent material such as soda lime glass or borosilicate glass, crystal or quartz. However, other materials may be used as long as the material can be insulated.

The cathode electrode 22 is made of, for example, a metal or a conductive metal oxide. The metal used for the cathode electrode 22 is composed of Ag, Au, Pt, Ti, Al, Cu, Cd, Pd, Zr, C, and the like, and the metal oxide is composed of ITO, TiO ₂ , ZnO, and the like. . The cathode electrode 22 may be composed of a simple substance or an alloy selected from these metals or metal oxides.

As shown in FIG. 3, the emitter 23 is composed of carbon nanotubes 101 formed in a matrix on the cathode electrode 22. A thin carbon film (not shown) is formed on the entire surface of the cathode electrode 22 or on the interface region between the cathode electrode 22 and the carbon nanotube 101. As will be described later, the carbon nanotube 101 is formed such that a carbon structure (amorphous carbon rod) 104 is converted into a carbon nanotube by a catalyst and is oriented substantially perpendicularly to the cathode substrate 20, which inhibits electric field concentration. The density is about 10 ¹⁰ pieces / cm ² or less, which is not uniform. Note that the joint between the carbon nanotube 101 and the carbon film is graphitized. Therefore, the carbon nanotube 101 is fixed to the cathode electrode 22.

  The anode substrate 10 and the cathode substrate 20 described above are arranged so that the phosphor layer 13 and the emitter 23 face each other, as shown in FIG.

The spacer 30 is provided between the anode substrate 10 and the cathode substrate 20, maintains the distance between the substrates 10 and 20 at a predetermined value, and seals between the substrates. The distance between the two substrates 10 and 20 is preferably 0.1 mm to 200 mm, and more preferably 1 mm to 10 mm. The space between the sealed substrates 10 and 20 is preferably 1.0 × 10 ⁻³ Pa or less, more preferably 1.0 × 10 ⁻⁴ Pa or less.

  As shown in FIG. 1, the anode electrode 12 and the cathode electrode 22 are connected to a power source 40 or a voltage terminal (not shown) by lead wires, respectively.

  According to such a configuration, since the emitter 23 on the cathode electrode 22 is composed of the carbon nanotubes 101 oriented substantially perpendicular to the cathode electrode 22, the electric field is concentrated on the tip of the carbon nanotubes 101, and electrons are efficiently used. Can be released well.

  In addition, since the density of the carbon nanotubes 101 is set in an appropriate range, inhibition of electric field concentration can be prevented. Furthermore, since the carbon nanotube 101 and the carbon film formed on the cathode electrode 22 are joined by graphite, the carbon nanotube 101 is fixed to the cathode electrode 22 and is difficult to come off. As described above, it is possible to obtain an electron emission electrode that is excellent in reliability, has high electron emission efficiency, and has an electron emission origin, that is, a substantially uniform density of the carbon nanotubes 101, and a light emitting device including the same.

  Next, a method for manufacturing the field emission light-emitting device 1 of the first embodiment will be described with reference to FIG.

First, a method for manufacturing the cathode substrate 20 will be described. An insulating substrate 21 made of an insulating material such as soda lime glass is prepared. A cathode electrode 22 is formed on the substrate 21. For example, a single or alloy target selected from metals such as Ag, Au, Pt, Ti, Al, Cu, Cd, Pd, Zr and C, and metal oxides such as ITO, TiO ₂ and ZnO is disposed. By sputtering this, metal or the like is deposited on the substrate 21 to a predetermined film thickness. By patterning this film, the cathode electrode 22 is formed as shown in FIG. Moreover, it is not limited to sputtering, It is also possible to use a vapor deposition method etc. Furthermore, a paste containing particles of these materials may be printed by a printing technique such as screen printing or ink jet printing, dried, and then patterned.

  Next, a solution of an organic compound (organometallic compound) containing a metal that serves as a catalyst for promoting the conversion of amorphous carbon to carbon nanotubes, such as a metal porphyrin, is applied onto the cathode electrode 22. This is dried to form a catalyst-containing film 102 as shown in FIG. The metal used as a catalyst should just be a metal which causes graphitization at high temperature, such as Fe, Co, Ni, Au, Pt, Cu, and Ga. As a solvent for dissolving the organometallic compound, for example, a polar solvent such as acetone, methanol, ethanol, isopropyl alcohol (IPA), toluene, or a mixture thereof can be used.

Next, a hydrocarbon compound such as phenanthrene is adsorbed on the catalyst-containing film 102 to form a hydrocarbon adsorption layer 103 as shown in FIG. Thereafter, as shown in FIG. 4 (d), the hydrocarbon adsorption layer 103 is decomposed by an electron beam excitation chemical vapor deposition method so that the thickness becomes 10 nm or less and the density becomes 10 ¹⁰ pieces / cm ² or less. A carbon structure (amorphous carbon rod) 104 is formed with a pitch.

  The amorphous carbon rod 104 is a prototype of the carbon nanotube 101 described later. Therefore, by forming the amorphous carbon rod 104 at a desired position, size, and density, the emitter 23 in which the carbon nanotubes 101 are arranged at a desired position, size, and density can be formed.

  Thereafter, the cathode substrate 20 is preferably heated at a temperature of about 400 ° C. to 600 ° C., more preferably about 500 ° C., to deposit the catalyst, thereby generating catalyst particles 105 as shown in FIG. The size of the generated catalyst particles 105 is preferably 0.5 to 3 times, more preferably about the same to a maximum of about 2 times the diameter of the amorphous carbon rod 104, so that the carbon nanotubes described later can be obtained. Can be efficiently and uniformly advanced. The size of the catalyst particles 105 can be adjusted by controlling the heating temperature or time. For example, when heated at about 500 ° C., the diameter of the catalyst particles 105 becomes about 10 nm.

  Subsequently, the heating temperature is increased by about 50 ° C. and the heating is continued. When the heating temperature is raised, the catalyst particles 105 located at the base of the amorphous carbon rod 104 enter the amorphous carbon rod 104, and as shown by the arrow Y in FIG. Move to.

  Thus, in the process in which the catalyst particles 105 move in the amorphous carbon rod 104, the entire catalyst particles 105 made of metal or a part of the surface becomes liquid. Since amorphous carbon and graphite have different solubility limit amounts in a liquid metal, amorphous carbon is selectively taken in and excess carbon in catalyst particles 105 is deposited. As a result, while the catalyst particles 105 spontaneously move to the tip of the amorphous carbon rod 104, the amorphous carbon is graphitized, and the carbon nanotubes 101 are formed accordingly.

  When a predetermined time set so that the catalyst particles 105 reach the tip from the base of the amorphous carbon rod 104 elapses, heating is stopped, for example, natural cooling is performed. Note that the heating time may be obtained in advance by experiments or the like.

  Through the above steps, an electron-emitting device including the emitter 23 composed of the carbon nanotubes 101 oriented substantially perpendicular to the substrate 21 and arranged at a predetermined pitch is completed.

  In the present embodiment, a carbon film is formed on the cathode electrode 22 and the joint between the carbon film and the carbon nanotube 101 is graphitized, so that the carbon nanotube 101 is fixed to the cathode electrode 22 with sufficient strength. .

  In the present embodiment, the amorphous carbon remaining on the surface of the carbon nanotube 101 without being graphitized can be removed by performing plasma treatment or the like in a trace amount of oxygen after graphitization. Thereby, the reliability as an electron-emitting device improves.

Next, a method for manufacturing the anode substrate 10 will be described. A transparent insulating substrate 11 made of an insulating material such as soda lime glass is prepared. On the substrate 11, an anode electrode 12, ITO, by sputtering ZnO, the transparent conductor typified by TiO _2, depositing a predetermined film transparent conductor to a thickness on the substrate 11. The anode electrode 12 is formed by patterning this film.

  A phosphor layer 13 is produced by screen printing on the substrate 11 on which the anode electrode 12 is formed. In order to screen-print the phosphor layer 13, a paste is formed using a phosphor, a binder, and a solvent. For example, a sulfide phosphor can be used as the phosphor, and nitrocellulose, ethyl cellulose, an acrylic resin, or the like can be used as the binder. As the solvent, for example, a solvent selected from terpineol, amyl acetate, butyl acetate, IPA, toluene, and xylene can be used. The phosphor layer 13 is applied to a thickness of 0.1 μm to 100 μm, and the applied phosphor layer 13 is baked at 350 ° C. to 500 ° C. in the atmosphere. The phosphor layer 13 can also be formed by a spray method, hand-painting printing, or a sedimentation method. Through the above steps, the anode substrate 10 is completed.

Next, the anode substrate 10, the cathode substrate 20, the spacer 30, and the exhaust glass tube are bonded together with a sealing frit glass in the atmosphere, and fired at 400 ° C. to 500 ° C. for 15 to 30 minutes for assembly. A vacuum is drawn from the exhaust glass tube of the assembled device, and the inside of the field emission light-emitting device 1 is sealed in a vacuum to produce the field emission light-emitting device 1. Internal field emission light-emitting device 1 is preferably a high vacuum degree 1.0 × ¹⁰ -3 Pa or less, perform vacuuming to be 1.0 × ¹⁰ -4 Pa or less and more preferably. The field emission light emitting device (planar light emitting device) 1 is completed through the above steps.

  According to the above-described embodiment, a method for manufacturing an electron-emitting device including the emitter 23 composed of the carbon nanotubes 101 oriented substantially perpendicular to the substrate 21 and arranged to have a predetermined density, and field emission light emission including the same A method for forming the element (planar light emitting element) 1 can be provided. Since the electron emission starting point is formed so that the electron emission element has a desired position and dispersion state, electrons can be emitted substantially uniformly and efficiently. In addition, the field emission light-emitting device 1 can emit light with good luminance and substantially uniform.

  The field emission light-emitting device 1 can be used as an illumination device by connecting lead wires from the anode electrode 12 and the cathode electrode 22 to terminals, for example. Further, by producing an electron emission array, it can be used as a fluorescent display tube.

(Second Embodiment)
In the first embodiment, the amorphous carbon rod 104 is formed by the electron beam excitation chemical vapor deposition method. However, the present invention is not limited to this, and an amorphous carbon rod having a predetermined size and a substantially uniform density is formed. If possible, the formation method itself is arbitrary. Hereinafter, a second embodiment, which is a manufacturing method for forming an amorphous carbon rod by patterning, will be described with reference to FIG. The steps other than the step of forming the amorphous carbon rod 205 are the same as those in the first embodiment.

  First, as shown in FIG. 5A, the cathode electrode 22 is formed on the substrate 21. On the cathode electrode 22, a solution such as metal porphyrin containing a metal serving as a catalyst is applied to form a catalyst-containing film 201 as shown in FIG. Next, as shown in FIG. 5C, a thick amorphous carbon film (carbon layer) 202 is formed by an ordinary chemical vapor deposition method or the like.

  Next, as shown in FIGS. 5D to 5F, a resist 203 is applied on the amorphous carbon thick film 202, and the resist 203 is patterned. Etching is performed using the patterned resist 204 as a mask to produce an amorphous carbon rod 205.

  Thereafter, as shown in FIGS. 5G and 5H, the carbon nanotubes 207 are formed by performing heating or the like as in the first embodiment. By this method, the time required for forming the amorphous carbon rod 205 can be shortened.

  Although the first and second embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and applications are possible.

  For example, in the first and second embodiments, the electron-emitting device including the cathode electrode 22 between the glass substrate 21 and the emitter 23 has been described. However, the cathode electrode 22 may not be provided as long as conduction is obtained.

  In the first and second embodiments, a solution containing a catalyst substance is applied onto the cathode electrode 22 to form the catalyst-containing films 102 and 201. However, a focused ion beam excited chemical vapor deposition method or an electron beam is used. The catalyst-containing films 102 and 201 may be formed by an excited chemical vapor deposition method or the like.

  In the first and second embodiments, after the catalyst-containing films 102 and 201 are formed, the catalyst particles 105 and 206 are deposited by heating. However, the catalyst particles 105 and 206 prepared in advance are dispersed in a solvent. It is also possible to apply on the cathode electrode 22. The catalyst particles 105 and 206 can be produced by, for example, a chemical vapor deposition method, a precipitation method, a focused ion beam excited chemical vapor deposition method, or the like.

  In the first and second embodiments, amorphous carbon is exemplified as the carbon material of the carbon structure that is the prototype of the carbon nanotubes 101 and 207. However, the solid phase reaction using the catalyst particles 105 and 206 described above is exemplified. Any carbon material can be used as long as it is converted into carbon nanotubes by the method, and the present invention is not limited to this. Further, the shape of the carbon structure to be converted into a carbon nanotube is not limited to a rod having a circular cross section, and may be, for example, a conical shape, a polygonal column, a pyramid, or a plate shape.

  In the first and second embodiments, the field emission light-emitting device 1 is assumed to be a light source that emits flat light. However, as shown in FIG. 6, cathode electrodes 22 and emitters 23 are arranged in a matrix. The fluorescent layers 13R, 13G, and 13B that emit light in the three primary colors R, G, and B are disposed at positions facing them, and the cathode electrodes 22 are individually driven to display a color image (FED). : Field Emission Display) 2 can also be configured.

  In the first and second embodiments, a planar light source is described. However, the field emission light-emitting element 1 may have a three-dimensional structure and is not limited to a planar surface.

1. Field emission light emitting device (planar light emitting device)
2 Field Emission Display 10 Anode Substrate 11, 21 Substrate 12 Anode Electrode 13, 13R, 13G, 13B Phosphor Layer 20 Cathode Substrate 22 Cathode Electrode 23 Emitter 30 Spacer 40 Power Supply 101, 207 Carbon Nanotube 102, 201 Catalyst-Containing Film 103 Hydrocarbon Adsorption layer 104, 205 Amorphous carbon rod (carbon structure)
105, 206 Catalyst particles 202 Amorphous carbon thick film (carbon layer)
203 resist 204 patterned resist

Claims (12)

A method of manufacturing an electron-emitting device that emits electrons from an emitter composed of carbon nanotubes,
Forming a catalyst-containing film containing a catalyst for promoting carbon nanotube formation on a substrate;
Forming a substantially vertically oriented carbon structure on the catalyst-containing film;
The catalyst in the catalyst-containing film is moved into the carbon structure to form a carbon nanotube, thereby forming the emitter composed of the carbon nanotubes oriented substantially perpendicular to the substrate. Process,
A method for manufacturing an electron-emitting device, comprising: The carbon nanotube conversion step includes
The method for manufacturing an electron-emitting device according to claim 1, wherein the catalyst is moved in the carbon structure by heating the substrate. The carbon nanotube conversion step includes
3. The method of manufacturing an electron-emitting device according to claim 2, wherein the substrate is heated for a predetermined time so that the catalyst reaches the tip from the base of the carbon structure. The carbon nanotube conversion step includes
Heating the substrate at a first temperature to deposit the catalyst contained in the catalyst-containing film to form catalyst particles;
Moving the catalyst particles within the carbon structure by heating the substrate at a second temperature;
The method of manufacturing an electron-emitting device according to any one of claims 1 to 3, further comprising: The step of forming the carbon structure includes
Adsorbing a hydrocarbon compound on the catalyst-containing film to form a hydrocarbon adsorption layer;
Irradiating the hydrocarbon adsorption layer with an electron beam to form the carbon structure;
5. The method of manufacturing an electron-emitting device according to claim 1, comprising: The step of forming the carbon structure includes
Forming a carbon layer on the catalyst-containing film;
Patterning the carbon layer to form the carbon structure;
5. The method of manufacturing an electron-emitting device according to claim 1, comprising:   The method for manufacturing an electron-emitting device according to any one of claims 1 to 6, wherein the carbon structure is an amorphous carbon rod.   8. The method of manufacturing an electron-emitting device according to claim 1, wherein a diameter of the catalyst particle is 0.5 to 3 times a diameter of the carbon structure. 9. The step of forming the carbon structure forms a plurality of the carbon structures at a predetermined pitch,
The carbon nanotube forming step converts each of the plurality of carbon structures into carbon nanotubes.
The method for manufacturing an electron-emitting device according to claim 1, wherein:   The method for manufacturing an electron-emitting device according to any one of claims 1 to 9, further comprising a step of forming a conductive layer on the substrate before the step of forming the catalyst-containing film. A step of disposing a phosphor layer facing the electron-emitting device manufactured by the method of manufacturing an electron-emitting device according to claim 1;
Disposing an anode electrode facing the electron-emitting device across the phosphor layer;
A method for forming a planar light emitting element, comprising:   An illumination device comprising the electron-emitting device manufactured by the method for manufacturing an electron-emitting device according to any one of claims 1 to 10.

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