JP2007073217A - Manufacturing method of field emission type cold cathode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a field emission type cold cathode enabling uniform electron emission with a low voltage by laminating a structural body having a micro-opening vertically in the surface of an orientative carbon nanotube film. <P>SOLUTION: This manufacturing method of the field emission type cathode includes a process to transfer the orientative carbon nanotube film to an electrode substrate from a holding substrate, a process to give a vertical opening to a two layer structural body comprising a conductive layer and an insulating layer, and a process to install the conductive layer side of the two layer structural body on the surface of the orientative carbon nanotube film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a method for partially exposing the surface of an oriented carbon nanotube (hereinafter referred to as CNT) film to the surface, and by concentrating the electric field on the uniformly exposed surface of the oriented CNT film, so that it is uniform at a low voltage. The present invention relates to a method for manufacturing a cold cathode capable of obtaining field electron emission with a high intensity. The present technology can be applied to a thin surface emitting display device such as a field emission display (hereinafter referred to as FED).

  CNT was discovered by Sumio Iijima in 1991 (see Non-Patent Document 1). The general shape is 0.5-100 nm in diameter and 1-100 μm in length, and is a very elongated hollow tube. Carbon material. In recent years, CNT is expected to be applied as a field electron emission type electron source. A negative voltage is applied to the electrode on which the field electron emission type electron source is arranged, and it is called a cold cathode because it does not emit heat. In particular, when CNT is used as an electron source of a surface-emitting display device such as an FED, a large number of electrons are required because the amount of electron emission from one CNT is insufficient. Furthermore, in order to obtain uniform surface light emission, it is necessary to concentrate the electric field on the CNTs having the same number per area and the same height.

  Various methods are known for manufacturing a field electron emission cold cathode using CNT, and there are a method of growing CNT directly on an electrode and a method of attaching separately prepared CNT to an electrode. Although the former has the advantage of shortening the manufacturing process, there is a problem that the CNT shape that can be manufactured is limited because the manufacturing conditions of CNT are limited by the properties of the electrode substrate. Although the latter requires a long manufacturing process, there are no restrictions on the CNT manufacturing conditions. Therefore, CNTs with various shapes and patterns can be manufactured, and it is advantageous for manufacturing a large area electrode.

  As a method of directly growing CNTs on an electrode, there is a method of growing CNTs vertically aligned on an electrode by attaching a catalyst to a predetermined position on the electrode substrate surface and performing CVD (for example, Patent Documents 1, 2, 3). However, since the electrode substrate used in these methods is exposed to high temperature carbon deposition conditions, the material of the electrode substrate may deteriorate.

  In addition, as a method of attaching separately prepared CNT to the electrode, a method of mixing CNT with a conductive paste and patterning the electrode by screen printing (for example, see Patent Document 4), mixing CNT with a solvent or a binder, dropping A method of forming a CNT layer on an electrode by coating or spraying (for example, see Patent Documents 5 and 6), a method of mixing CNT with a solvent or a binder, and extruding the electrode through a metal mesh (for example, a non-patent document) 2). These are methods in which the adhesion between the electrode and the CNTs is strengthened and electrically conductive. However, nanoscale substances such as CNTs tend to aggregate even if mixed with other fluid substances, and it is difficult to mix them uniformly. If CNT and other fluid substances are attached to the electrode in an unevenly mixed state, the density of the CNT contained in each electron source on the electrode is not constant, and irregularities occur on the surface of the electron source. As a result, the surface emitting display device becomes uneven. Here, there is a means of increasing the ratio of the solvent so that it is mixed as uniformly as possible. However, if the solvent remains in the electrode, it becomes a hindrance when performing field electron emission in a high vacuum, so use of the solvent is minimized. It is desirable.

  As a method not using a binder, there is a method in which a CNT layer is formed on the surface of a filter by passing a CNT suspension through a filter, and the CNT layer is transferred to an electrode (for example, see Non-Patent Document 3). However, since the CNT aggregate on the filter is directly attached to the Teflon (registered trademark) sheet as an electrode, it is not suitable for pattern formation. There is also a problem with the adhesion between the electrode and the CNT.

  As a transfer method similar to the above-mentioned Non-Patent Document 3, although a method for producing a field electron emission cold cathode is not mentioned, an oriented CNT aggregate is grown on a substrate, and the oriented CNT aggregate is A method of transferring to a second substrate is also disclosed (for example, see Patent Document 7). However, this method is also a method of batch-transferring film-like CNTs, and does not clearly indicate a method of finely dividing or partially covering the surface.

  In Patent Document 8, an aligned CNT is formed, the CNT portion is transferred to an electrode plate except for a growth support member, and an electron emission layer is opened. However, in order to maintain the shape of a single CNT that is oriented but is isolated, a complicated operation of embedding in a matrix material is required.

  Here, as CNTs for field electron emission type cold cathodes, it is known that the thinner each one has better field emission capability. In addition, it is known that the CNT aggregate is oriented in the direction perpendicular to the electrode substrate, and the density is lower or the smaller the area of the CNT aggregate, the better the field emission ability. ing. In view of the present situation as described above, the present inventors have succeeded in producing an aligned CNT aggregate composed of CNTs having a height of 10 μm or more and a tube diameter of 10 nm or less (see Patent Document 9). Electron emission from the columnar assembly was also successful (see Patent Document 10).

As a method for selectively growing an oriented CNT aggregate in a minute area on the order of μm, a method of patterning and arranging a catalytic metal by a mask method (see Patent Document 1), a method of patterning and etching a catalytic metal by a mask method (Refer to Patent Document 11) and a method of forming a catalyst layer by sputtering and patterning in a stripe shape (refer to Patent Document 8). However, the CNTs manufactured by these methods have a large tube diameter of 10 nm or more.
Special Table 2002-530805 gazette JP 2001-15077 A JP 2003-100198 A JP-A-11-260249 JP 2000-340098 A JP 2000-311578 A Special table 2003-500325 gazette JP 2005-116469 A JP 2002-338221 A Japanese Patent Application No. 2004-256429 Special table 2003-500324 gazette S.Iijima, "Helical microtubules of graphite carbon", Nature, 354, p56-58 (1991) WBChoi et al., "Fully sealed high-brightness carbon-nanotube field-emission display", Applied Physics Letters, 75, 20, p3129-3131 (1999) WAde Heer et al., "A Carbon Nanotube Field-Emission Electron Source", Science, 270, p1179-1180 (1995)

  In order to operate a surface light emitting display device using a field electron emission type cold cathode, it is advantageous to emit electrons with as low voltage and uniform intensity as possible. Therefore, it is desirable that each CNT used in the field electron emission type cold cathode has as small a tube diameter as possible. However, since single-walled CNT has a problem in strength, a multilayered CNT having two or more layers is desirable.

  As the CNT aggregate used for the field electron emission type cold cathode, an oriented CNT aggregate in which a large number of CNTs are oriented in a direction perpendicular to the electrodes and the height is constant is preferable. If it is vertically aligned, the maximum electron emission intensity can be obtained in the vertical direction as the sum of a plurality of CNT electron sources. Moreover, if the height of the surface is constant, uniform electron emission can be obtained in the planar direction. Furthermore, in the case of field electron emission, the closer the distance between the tip of the CNT and the extraction electrode, the lower the voltage for extracting electrons, so if the height of the electron source is constant, the extraction electrode is close to the surface of the electron source. Even if they are used, the uniformity of the distance can be maintained, and the extraction voltage can be lowered to obtain the same electron emission intensity.

  However, it is said that in order to extract electrons from the entire surface of the oriented CNT aggregate, the extraction electrode needs to be separated by an aspect ratio of 1 or more. For example, in order to extract electrons from the entire oriented CNT film formed in a planar shape with a diameter of 1 mm, the extraction electrode must be set apart by 1 mm or more. Even if the formed CNT has a high threshold electric field of 1 V / micron. Even for CNT, it is necessary to apply a voltage of 1 KV or more.

  From the above consideration, the oriented CNT aggregate used for the field electron emission type cold cathode preferably has a smaller area of the electron emission surface. In addition, by reducing the area of the oriented CNT aggregate, a larger number of oriented CNT aggregate electron sources can be arranged per pixel or per unit area. I can expect.

  Furthermore, the oriented CNT aggregate used for the field electron emission type cold cathode has a structure in which the extraction electrode can be easily installed near the surface of the CNT, or a triode that can be brightly displayed with a low extraction voltage and an acceleration voltage in the future. Desirable for developing devices.

  In view of the above, the present invention has a vertical orientation, a constant height, and a CNT aggregate having a small tube diameter and exposed to a small area, that is, perpendicular to the surface of the oriented CNT film. It is an object of the present invention to provide a method for manufacturing a field emission cold cathode that enables uniform electron emission at a low voltage by laminating structures having minute openings.

As a result of intensive research on a method of manufacturing a field emission cold cathode, the present inventors have made a two-layer structure of a conductive layer and an insulating layer having a minute opening perpendicular to the surface of the oriented CNT film on the electrode substrate. As a result, the inventors have found a method of manufacturing a field emission cold cathode that enables uniform electron emission at a low voltage, and have reached the present invention. That is, the present invention is as follows.
(1) a step of transferring the oriented carbon nanotube film from the holding substrate to the electrode substrate, a step of forming a vertical opening in a two-layer structure comprising a conductive layer and an insulating layer, and a surface of the oriented carbon nanotube film A method for manufacturing a field emission cold cathode, comprising a step of installing the conductive layer side of the two-layer structure.
(2) The step of transferring the oriented carbon nanotube film from the holding substrate to the electrode substrate includes a step of producing an oriented carbon nanotube film on the base substrate surface, and a step of applying a conductive binder to the electrode substrate surface And the surface of the oriented carbon nanotube film and the surface of the conductive binder, and then the base substrate is peeled off leaving the oriented carbon nanotube film portion adhered to the conductive binder, and the oriented carbon nanotube film The manufacturing method of the field emission type cold cathode as described in said (1) including the process to transcribe | transfer.
(3) The step of transferring the oriented carbon nanotube film from the holding substrate to the electrode substrate includes a step of producing an oriented carbon nanotube film on the base substrate surface, and the surface of the oriented carbon nanotube film is reversible. After bonding to the surface of a flexible substrate having an adhesive surface, leaving the oriented carbon nanotube film adhered to the flexible substrate surface, peeling the base substrate and transferring the oriented carbon nanotube film; A step of applying a conductive binder to the surface of the electrode substrate, and an orientation in which the surface of the oriented carbon nanotube film transferred to the flexible substrate and the surface of the conductive binder are bonded together and then bonded to the conductive binder Including the step of transferring the oriented carbon nanotube film by peeling off the flexible substrate leaving the carbon nanotube film portion. Manufacturing method of field emission type cold cathode.
(4) The step of transferring the oriented carbon nanotube film from the holding substrate to the electrode substrate includes the step of producing an oriented carbon nanotube film on the surface of the base substrate, and the surface of the oriented carbon nanotube film is first After adhering to the surface of a flexible substrate having a reversible adhesive surface, the base substrate is peeled off leaving the oriented carbon nanotube film adhered to the first flexible substrate surface, and the oriented carbon nanotube film And bonding the surface of the oriented carbon nanotube film transferred to the first flexible substrate to the surface of the flexible substrate having a second reversible adhesive surface, A step of transferring the oriented carbon nanotube film by peeling off the first flexible substrate while leaving the oriented carbon nanotube film adhered to the surface of the flexible substrate, and a conductive binder on the surface of the electrode substrate. An orientation carbon nanotube bonded to the conductive binder after bonding the surface of the orientation carbon nanotube film transferred to the second flexible substrate and the surface of the conductive binder The method for producing a field emission cold cathode according to (1), comprising a step of transferring the oriented carbon nanotube film by peeling off the second flexible substrate while leaving a film portion.
(5) The field emission type according to (1), wherein a laser irradiation method, a photolithography method, a sand blast method, or an etching method is used in the step of forming a vertical opening in a two-layer structure including a conductive layer and an insulating layer. A method for producing a cold cathode.
(6) The method of manufacturing a field emission cold cathode according to (1), wherein the diameter of the opening formed in the two-layer structure including the conductive layer and the insulating layer is 100 micrometers or less.
(7) The method for producing a field emission cold cathode according to (1), wherein the material forming the conductive layer is a metal or an alloy having a melting point of 100 to 500 ° C.
(8) Production of field emission type cold cathode according to (1), wherein adhesion, pressure bonding, or thermocompression bonding is performed in the step of placing the conductive layer side of the double-layer structure on the surface of the oriented carbon nanotube film. Method.
(9) A field emission cold cathode obtained by any one of the methods (1) to (8).
(10) A triode device comprising the field emission cold cathode according to (9), a gate electrode, and a counter anode.

  According to the method for manufacturing a field emission cold cathode of the present invention, a field emission type cold cathode having a laminated structure in which an assembly of oriented CNTs having a vertical orientation and a uniform height and density is exposed in a small area. Can be easily manufactured in a large area. By using the cathode manufactured by the method of the present invention, it is possible to obtain a surface-emitting display device that operates at a low voltage and has uniform luminance. In the future, it has the potential to develop a triode display device that can be operated at a lower voltage by installing an extraction electrode.

  The method of manufacturing a field emission cold cathode in this embodiment includes a step of transferring an oriented carbon nanotube film from a holding substrate to an electrode substrate, and a step of providing a vertical opening in a two-layer structure comprising a conductive layer and an insulating layer And the conductive layer side of the double-layer structure is provided on the surface of the oriented carbon nanotube film.

  First, there are the following three methods (A, B, or C methods) for transferring the oriented carbon nanotube film from the holding substrate to the electrode substrate. The holding substrate is a general term for a basic substrate or a flexible substrate in the following AC methods.

  As shown in FIG. 1, the method A includes a step of producing an oriented carbon nanotube film on the surface of the base substrate, a step of applying a conductive binder to the surface of the electrode substrate, a surface of the oriented carbon nanotube film, After bonding the surface of the conductive binder, the method includes a step of transferring the oriented carbon nanotube film by peeling off the base substrate leaving a portion of the oriented carbon nanotube film adhered to the conductive binder.

  As shown in FIG. 2, the method B is a step of producing an oriented carbon nanotube film on the surface of the base substrate, and the surface of the oriented carbon nanotube film is a surface of a flexible substrate having a reversible adhesive surface. After bonding to the flexible substrate surface, leaving the oriented carbon nanotube film adhered to the flexible substrate surface, peeling the basic substrate and transferring the oriented carbon nanotube film, and applying a conductive binder to the electrode substrate surface And bonding the surface of the oriented carbon nanotube film transferred to the flexible substrate and the surface of the conductive binder, and leaving the portion of the oriented carbon nanotube film bonded to the conductive binder, the flexible This is a method including a step of transferring the oriented carbon nanotube film by peeling the conductive substrate.

The flexible substrate having a reversible adhesive surface means a flexible substrate that can adhere or peel off an object on the surface, and may be any substrate that has weak adhesiveness or adhesiveness on the surface. . There are cases where the pressure-sensitive adhesive or adhesive is applied to the entire surface of the substrate or partially according to a pattern, and cases where the substrate itself is sticky or adhesive. In addition, a substrate that does not have adhesiveness or tackiness under a normal environment, or a substrate that exhibits adhesiveness or tackiness under a special environment such as a humid atmosphere or high temperature can be used. Conversely, a substrate that has adhesiveness or tackiness under a normal environment or a substrate that loses adhesiveness or tackiness under a special environment such as light irradiation or high temperature can be used.
As a flexible substrate material, a material that can be deformed when pressed against an electrode substrate can be used, and a single or multilayer structure made of an adhesive resin, a thermosetting resin, a thermoplastic resin, a photocurable resin, or a water-soluble resin. Sheets can be used.

  Specific examples of the flexible substrate include a single-layer sheet made of a thermoplastic resin, an adhesive acrylic resin / thermoplastic polyolefin two-layer structure sheet, and an adhesive EVA / thermoplastic polyolefin adhesive two-layer structure sheet. Examples of the thermoplastic resin include polyolefin, polyester, polycarbonate, polyamide, and polyimide. Moreover, the sheet | seat consisting of the thermosetting resin illustrated by an epoxy resin and a phenol resin, and the sheet | seat consisting of water-soluble resin illustrated by polyvinyl alcohol can also be used.

  As shown in FIG. 3, the method C includes a step of producing an oriented carbon nanotube film on the surface of the base substrate, and the flexibility of the oriented carbon nanotube film having a first reversible adhesive surface. After bonding to the surface of the substrate, leaving the oriented carbon nanotube film adhered to the surface of the first flexible substrate, separating the base substrate and transferring the oriented carbon nanotube film; The orientation of the oriented carbon nanotube film transferred to the flexible substrate is adhered to the surface of the flexible substrate having the second reversible adhesive surface and then adhered to the surface of the second flexible substrate. Removing the first flexible substrate while leaving the carbon nanotube film, transferring the oriented carbon nanotube film, applying a conductive binder to the surface of the electrode substrate, and the second flexible substrate Transcribed into After adhering the surface of the directional carbon nanotube film and the surface of the conductive binder, the second flexible substrate is peeled off leaving the oriented carbon nanotube film part adhered to the conductive binder, and the oriented carbon The method includes a step of transferring a nanotube film.

  As the flexible substrate having the first and second reversible adhesive surfaces, the same sheet as the flexible substrate having the reversible adhesive surface can be used, and the oriented carbon nanotubes are used in the third step. In order to improve transferability by making a difference in adhesiveness with the film, it is preferable to use different types of sheets.

  Since the oriented CNT film in the present invention is used as a field emission electron source, the height and density are preferably constant. Each CNT preferably has the smallest possible tube diameter. However, since single-walled CNT has a problem in strength, a multilayered CNT having two or more layers is desirable. Furthermore, the orientation CNT film on the first substrate is preferably one in which the adhesion between the first substrate and the CNT on the substrate is weak in order to perform an operation of peeling from the first substrate later. In addition, in the present invention, the oriented carbon nanotube film transferred from the holding substrate to the electrode substrate is required to be made of a material that can withstand the subsequent lamination operation. That is, it is desirable to maintain the shape even in external operations such as bonding, pressure bonding, and thermocompression bonding.

  Examples of the oriented CNT film satisfying the above conditions include oriented CNT films disclosed in Japanese Patent Application Laid-Open Nos. 2002-338221 and 2004-002182, which have been invented by the present inventors. As described in Japanese Patent Application Laid-Open No. 2002-338221, the CNT film is a base substrate prepared by vapor-depositing aluminum on a support substrate to carry a CNT generation catalyst to produce a CNT growth substrate, It can be produced by decomposing a carbon compound on a substrate. Further, as described in JP-A-2004-002182, the CNT film is formed on a base substrate in which a sol-gel porous carrier having pores of 0.1 to 50 nm on a support substrate is formed. Can be produced by preparing a substrate for growing CNTs and decomposing a carbon compound on the substrate.

  The CNT production catalyst used here may be any catalyst that forms CNTs. For example, iron, cobalt, nickel, molybdenum, or a compound thereof is used. These catalysts can be used alone or as a mixture. Any catalyst loading method may be used as long as the catalyst is supported on a carrier, and examples thereof include an impregnation method, an immersion method, and a sol-gel method. In some cases, the CNT growth substrate is heated after supporting the catalyst.

  By decomposing the carbon compound using the CNT growth substrate, an oriented CNT film is formed on the substrate. Any carbon compound may be used as long as it generates CNTs in the presence of a suitable catalyst, for example, saturated hydrocarbon compounds such as methane, ethane, and propane, and unsaturated hydrocarbon compounds such as ethylene, propylene, and acetylene. , Aromatic hydrocarbon compounds such as benzene and toluene, and oxygen-containing hydrocarbon compounds such as methanol, ethanol, and acetone, preferably methane, ethylene, propylene, acetylene, methanol, ethanol, and propanol. The carbon compound may be introduced in the form of a gas, mixed with an inert gas such as argon, or introduced as a saturated vapor in the inert gas. Also good. Further, a hetero element-containing nanotube can be obtained by mixing a compound containing a hetero element such as boron or nitrogen incorporated into the nanotube.

  As the decomposition reaction of the carbon compound, thermal decomposition is the most common, and a preferable reaction temperature is 400 to 1100 ° C, more preferably 500 to 900 ° C, and a preferable reaction pressure is 1 kPa to 1 MPa, more preferably 0.01 to 0. .12 MPa.

  In the present embodiment, the catalyst particles are often included in the tip portion of each CNT, that is, the tip side of the oriented CNT film, after the CNTs are generated. According to the manufacturing method of the present invention, an oriented CNT film having a height of 1 to 100 μm can be uniformly formed on a basic substrate. At this time, the outer diameter of each CNT can be manufactured in the range of 1 to 10 nm. Further, the basic substrate and the CNT film on the basic substrate are only in physical contact, and the adhesion between the basic substrate and the CNT film on the substrate is weak.

The oriented carbon nanotube film transferred from the holding substrate to the electrode substrate by the A to C methods does not break its shape even with a high pressure bonding force of 100 kg / cm ² .

Next, the step of forming a vertical opening in a two-layer structure composed of a conductive layer and an insulating layer in the method for manufacturing a field emission cold cathode according to the present invention will be described.
First, a two-layer structure including a conductive layer and an insulating layer is prepared. The thickness of each layer is 0.1 to 1 μm for the conductive layer and 5 to 50 μm for the insulating layer, but is not limited thereto. Also, the preparation method of the two-layer structure is not particularly limited, but there is a method in which an insulating layer is fixed to a holding film, if necessary, thinning treatment is performed to a predetermined thickness, and a conductive layer is formed on the surface. Convenient.

Here, the holding film may be a film having the same function as the flexible substrate having the above-described reversible adhesive surface, but it is necessary to peel from the two-layer structure in a later step. Since the two-layer structure is an inflexible thin film, it needs to be peeled off by applying as little force as possible or without applying heat. Therefore, the holding film used here is particularly preferably a flexible film that loses tackiness under mild conditions such as a UV cured film.
As a specific UV cured film, a two-layer structure sheet of adhesive acrylic resin / polyolefin is typical.

  As a method for forming the conductive layer, a normal thin film lamination method may be used, and a vapor deposition method, a sputtering method, a screen printing method, or the like is preferable. The conductive layer may be made of any conductive material such as metal, but a low melting point metal or low melting point alloy having a melting point of 100 to 500 ° C. is more preferable. Specific examples of the low melting point metal include indium, tin, and zinc, and examples of the low melting point alloy include indium-tin and tin-zinc.

The insulating layer is preferably made of an insulating material and can maintain its shape even at a vacuum sealing temperature (about 500 ° C.). Moreover, the thing which does not generate | occur | produce a gas in a vacuum is preferable, and the glassy substance which has silicon as a main component is used normally. In addition, a photosensitive organosilicate film developed in recent years also satisfies this function and can be used.

  As the vertical opening method, a normal thin film opening method may be used, and a laser irradiation method, a photolithography method, a sand blast method, an etching method, or the like is used.

The opening diameter is preferably 100 μm or less. For example, in the case of an opening diameter of 100 μm, in order to extract electrons from the front surface of the CNT in the opening, when the extraction electrode is installed at a position of 100 μm from the CNT surface, the CNT has a threshold electric field of 1 V / micron. If there is, it will be possible at 100V.
Further, even if the opening is too close, it is difficult to apply an electric field to the CNT, which is not preferable. However, if the opening is too far away, a sufficient amount of current per unit area cannot be obtained. In this manufacturing method, it is preferable to set a distance approximately the same as the opening diameter, that is, to set the pitch to about twice the opening diameter. In this case, the ratio per unit area of the opening is about 20%.

Next, the step of installing the conductive layer side of the two-layer structure on the surface of the oriented carbon nanotube film in the method for producing a field emission cold cathode of the present invention will be described.
As a basic operation, only the surface of the oriented carbon nanotube film transferred to the electrode surface in the first step is brought into contact with the surface on the conductive layer side of the open two-layer structure obtained in the second step. Good. When a holding film is used in the second step, it needs to be peeled off. In this case, it is convenient to select in advance a film that can lower the tackiness, such as a UV curable film, as the holding film.

  Further, when the strength is insufficient as a device simply by contact, an operation of mechanically and electrically connecting the conductive layer and the oriented carbon nanotube film, such as adhesion, pressure bonding, and thermocompression bonding, is performed. In this case, it is convenient to select a low melting point metal or a low melting point alloy as the conductive layer in advance.

Below, the manufacturing method of the field emission type cold cathode in this embodiment is demonstrated with simple sectional drawing.
First, as shown in FIG. 4, an insulating plate 8 is prepared, and a conductive layer 9 is formed on the surface thereof. The thickness of each layer is not limited to 0.1 to 1 μm for the conductive layer and 5 to 50 μm for the insulating plate. As a method for forming the conductive layer 9, a general method for forming a metal layer may be used, and vacuum deposition, sputtering, or the like is used.

  Next, as shown in FIG. 5, a vertical opening process is performed on the two-layer structure obtained as described above. As described above, a laser irradiation method, a photolithography method, a sand blast method, an etching method, or the like is used as the opening method. A method of fixing to the holding film 10 such as a UV cured film is also desirable so that the two-layer structure is not broken during the opening treatment.

  As shown in FIG. 6, the surface of the conductive layer 9 in the two-layer structure subjected to the opening treatment in FIG. 5 and the surface of the oriented CNT film 2 transferred to the electrode substrate by any of the above AC methods are contacted. Then, the target field emission cold cathode 11 is obtained by peeling the holding film 10 as shown in FIG. Here, when the holding film 10 is a UV cured film, the holding film 10 can be more easily peeled off by irradiating UV from the film side.

  When the material for forming the conductive layer 9 is a low melting point metal or a low melting point alloy, the conductive layer 9 and the oriented CNT film 2 are heated by heating the field emission cold cathode 11 to the melting point of the low melting point metal. Can be more mechanically and electrically connected.

  When a potential is applied between the field emission cold cathode obtained by the manufacturing method of the present invention and the counter anode 12 in a vacuum, 13 portions of the surface of the oriented CNT film 2 exposed to the minute mouth face each other. Since there is a potential difference with respect to the anode 12, electron emission is performed when the threshold value is exceeded (see FIG. 8). Since there is no potential difference between the unexposed portion 14 and the conductive layer 9 in contact therewith, neither electrons are emitted nor discharge breakdown occurs. Comparing the field emission cold cathode of FIG. 8 with the cold cathode (see FIG. 9) using the columnar aggregate 15 of oriented CNTs as an electron source, the portion 13 exposed in the micro-mouth of FIG. If the area of the surface 16 of the columnar aggregate 15 is equal, the electron emission ability is equivalent.

  Here, when a gate layer (gate electrode) 17 is further laminated on the insulating layer 8 of the field emission cold cathode of FIG. 8 (see FIG. 10), it is possible to develop a triode device by installing the counter anode 12. It is.

[Step of growing oriented CNT film]
A square silica alumina plate having a composition of 25% silica and 75% alumina and a thickness of 2 mm and a side of 15 mm was selected as a support substrate, and aluminum was coated by vapor deposition by a vacuum deposition method. At this time, the thickness of the aluminum thin film was 0.5 μm. Subsequently, it was immersed in a cobalt nitrate aqueous solution having a concentration of 0.2 mol / l for 2 hours. After raising the substrate, the substrate was baked in air at 400 ° C. for 3 hours to obtain a basic substrate. After firing, the base substrate was placed in a quartz tube furnace with the aluminum deposition side facing up horizontally. The tube furnace was heated to 700 ° C. while blowing argon at 1000 cm ³ / min in the horizontal direction. Then, while holding 700 ° C., and blown into a tubular furnace of propylene to argon 1000 cm ³ / min was mixed with 300 cm ³ / min. After flowing a propylene / argon mixed gas for 2 minutes, while switching to argon only again, the heating of the tubular furnace was stopped and the mixture was allowed to cool to room temperature. After completion of the reaction, the surface of the basic substrate was observed with a scanning electron microscope (SEM). As a result, it was confirmed that an oriented CNT film having a thickness of 10 μm was formed on the upper side of the basic substrate.
The film was made of CNTs oriented in the vertical direction, and had a constant thickness and a smooth surface. When this alignment film was observed with a transmission electron microscope (TEM), the CNT constituting the alignment film was a multilayer CNT having an outer diameter of 5 to 8 nm and about 5 to 7 layers.

[Process of transferring oriented carbon nanotube film from base substrate to electrode substrate]
A re-peeling film A (adhesive strength 0.02 N / cm) 20 mm × 20 mm made of adhesive acrylic resin / polyethylene terephthalate is brought into contact with the surface of the oriented CNT film on the base substrate, and 10 kg / cm ^{2 is applied} for 3 minutes with a press. Pressed. After the pressure bonding, the re-peeling film A was peeled from the base substrate, whereby all the 15 mm × 15 mm oriented CNT films were transferred to the re-peeling film A. Further, the re-peeling film B (adhesive strength 0.04 N / cm) 25 mm × 25 mm was brought into contact with the surface of the oriented CNT film on the re-peeling film A, and pressurized with a press at 5 kg / cm ² for 15 minutes. After the pressure bonding, the re-peeling film B was peeled from the re-peeling film A, whereby all the 15 mm × 15 mm oriented CNT films were transferred to the re-peeling film B. Here, a 30 mm × 100 mm ITO glass plate (thickness 1.1 mm) was prepared as an electrode substrate, and a conductive silver paste was screen-printed in a size of 10 mm × 10 mm on the center of the surface to a thickness of about 4 μm. After printing, the surface of the oriented CNT film on the re-peeling film B and the conductive silver paste were brought into contact with each other and pressed with a press at 2 kg / cm ² for 60 minutes. After the pressure bonding, the re-peeling film B was peeled from the ITO glass plate, whereby an oriented CNT film having a size of 10 mm × 10 mm was transferred onto the conductive paste.

[Process for forming a vertical opening in a two-layer structure comprising a conductive layer and an insulating layer]
A glass plate having a size of 10 mm × 10 mm and a thickness of 100 μm was fixed to a UV cured film made of acrylic resin / polyolefin and polished to a thickness of 30 μm. Next, tin was laminated on the glass surface by sputtering to a thickness of 0.2 μm. Further, while the obtained glass / tin two-layer structure was fixed to the UV cured film, the entire surface was subjected to an opening process in the vertical direction with an opening diameter of 30 μm and a pitch of 60 μm using a laser.

[Step of installing double-layer structure on the surface of oriented carbon nanotube film]
The orientation CNT film surface on the electrode substrate is brought into contact with the tin lamination surface of the two-layer structure, and a UV cured film, a glass plate, tin, an orientation CNT film, a conductive paste, and an electrode substrate are laminated in that order from the top. Got the body. Upper, 500 mJ / cm ² UV was irradiated from the UV cured film side. After irradiation, the UV cured film was peeled from the glass plate. Furthermore, 0.5 kg of SUS block was loaded on the glass plate, and the whole was heated to 400 ° C. After cooling, the target field emission cold cathode was obtained by removing the SUS block.
As a result of conducting field electron emission measurement as a cathode, the threshold electric field was 0.8 V / μm, the current density was 5 mA / cm ² , and the achieved electric field was 2.0 V / μm.

Method for transferring an oriented CNT film from a holding substrate to an electrode substrate (Method A) Method for transferring an oriented CNT film from a holding substrate to an electrode substrate (Method B) Method for transferring an oriented CNT film from a holding substrate to an electrode substrate (Method C) Two-layer structure comprising a conductive layer and an insulating layer Two-layer structure after opening treatment fixed to holding film Contact between the conductive layer surface of the two-layer structure subjected to the opening treatment and the CNT film surface transferred to the electrode substrate Field emission cold cathode obtained by peeling the holding film Field emission cold cathode with counter anode installed Cold cathode using columnar aggregate of oriented CNT as electron source Triode device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base substrate 2 Oriented CNT film | membrane 3 Electrode substrate 4 Conductive binder 5 Flexible substrate 6 First flexible substrate 7 Second flexible substrate 8 Insulating plate 9 Conductive layer 10 Holding film 11 Field emission type cold Cathode 12 Opposite anode 13 Exposed surface of oriented CNT film 14 Unexposed surface of oriented CNT film 15 Columnar aggregate 16 of oriented CNT Surface 17 of columnar aggregate of oriented CNT Gate layer

Claims (10)

Transferring the oriented carbon nanotube film from the holding substrate to the electrode substrate;
A field emission type comprising: a step of providing a vertical opening in a two-layer structure comprising a conductive layer and an insulating layer; and a step of placing the conductive layer side of the double-layer structure on the surface of the oriented carbon nanotube film A method for producing a cold cathode.   The step of transferring the oriented carbon nanotube film from the holding substrate to the electrode substrate includes a step of producing an oriented carbon nanotube film on the surface of the base substrate, a step of applying a conductive binder to the surface of the electrode substrate, After adhering the surface of the oriented carbon nanotube film and the surface of the conductive binder, the oriented carbon nanotube film is transferred by peeling off the base substrate leaving the oriented carbon nanotube film part adhered to the conductive binder. The manufacturing method of the field emission type cold cathode of Claim 1 including a process.   The step of transferring the oriented carbon nanotube film from the holding substrate to the electrode substrate includes the step of producing an oriented carbon nanotube film on the base substrate surface, and the reversible adhesive surface of the surface of the oriented carbon nanotube film. A step of transferring the oriented carbon nanotube film by peeling off the base substrate leaving the oriented carbon nanotube film adhered to the surface of the flexible substrate after bonding to the surface of the flexible substrate having Applying the conductive binder to the substrate, and bonding the surface of the oriented carbon nanotube film transferred to the flexible substrate and the surface of the conductive binder, and then aligning the oriented carbon nanotubes with the conductive binder The field emission type according to claim 1, further comprising a step of transferring the oriented carbon nanotube film by peeling off the flexible substrate while leaving a film portion. Method of manufacturing the cathode.   The step of transferring the oriented carbon nanotube film from the holding substrate to the electrode substrate includes the step of producing an oriented carbon nanotube film on the surface of the base substrate, and the first reversible surface of the oriented carbon nanotube film. After bonding to the surface of a flexible substrate having an adhesive surface, the orientation substrate is peeled off while leaving the oriented carbon nanotube film adhered to the first flexible substrate surface, and the oriented carbon nanotube film is transferred. And bonding the surface of the oriented carbon nanotube film transferred to the first flexible substrate to the surface of the flexible substrate having a second reversible adhesive surface, A step of transferring the oriented carbon nanotube film by peeling off the first flexible substrate while leaving the oriented carbon nanotube film adhered to the surface of the oriented substrate, and a conductive binder on the surface of the electrode substrate. A portion of the oriented carbon nanotube film bonded to the conductive binder after bonding the surface of the oriented carbon nanotube film transferred to the second flexible substrate and the surface of the conductive binder. 2. The method of manufacturing a field emission cold cathode according to claim 1, further comprising the step of transferring the oriented carbon nanotube film by peeling the second flexible substrate while leaving the film.   2. The method of manufacturing a field emission cold cathode according to claim 1, wherein a laser irradiation method, a photolithography method, a sand blast method, or an etching method is used in the step of forming a vertical opening in a two-layer structure comprising a conductive layer and an insulating layer. Method.   2. The method of manufacturing a field emission cold cathode according to claim 1, wherein the diameter of the opening formed in the two-layer structure including the conductive layer and the insulating layer is 100 micrometers or less.   The method of manufacturing a field emission cold cathode according to claim 1, wherein the material forming the conductive layer is a metal or alloy having a melting point of 100 to 500C.   The method for producing a field emission cold cathode according to claim 1, wherein in the step of placing the conductive layer side of the double-layer structure on the surface of the oriented carbon nanotube film, adhesion, pressure bonding, or thermocompression bonding is performed.   A field emission cold cathode obtained by the method according to claim 1.   A triode device comprising the field emission cold cathode according to claim 9, a gate electrode, and a counter anode.

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