JP4484047B2 - Method for producing patterned columnar aggregate of oriented carbon nanotubes and field emission cold cathode - Google Patents

Description

  The present invention provides a method for patterning a columnar aggregate of oriented carbon nanotubes (hereinafter referred to as CNT) and a method for forming a patterned columnar aggregate of oriented CNTs on an electrode at a low voltage. The present invention relates to a method for manufacturing a cold cathode capable of obtaining field electron emission with uniform intensity. The present technology can be applied to a thin image 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, CNTs are expected to be applied as field electron emission type electron sources. A negative voltage is applied to the electrode on which the field electron emission type electron sources are arranged, and further heat is not emitted, so it is called a cold cathode. In particular, when CNT is used as an electron source of an image display device such as an FED, a large number of electrons are required because the amount of emitted electrons is insufficient from one CNT. Furthermore, since a unique electron source for illuminating each pixel of the FED is required, it is necessary to insulate each electron source and energize the control circuit.

  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. The former has the advantage of shortening the manufacturing process, but the CNT manufacturing conditions are limited by the properties of the electrode substrate, so that the CNT shapes that can be manufactured may be limited. 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 (see, for example, Patent Documents 1 and 2). ). 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 forming a pattern on the electrode by screen printing (for example, see Patent Document 3), mixing CNT with a solvent or a binder, dropping A method of forming a CNT layer on an electrode by applying or spraying (for example, see Patent Document 4), a method of mixing CNT with a solvent or a binder, and extruding the electrode through a metal mesh (for example, see 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 image 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 5). Also disclosed is a method in which a CNT growth substrate is covered with a photoresist mask, patterned by development and dissolution, CNT is grown by patterning, and transferred to a second substrate (Patent Document 6). However, it is necessary to dissolve the residual photoresist layer at the time of transfer, and the process becomes longer and there is a concern about contamination of CNTs.

  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 that the lower the density or the smaller the area of the CNT aggregate, the better the field emission ability. Yes. In view of the current 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 7). He also succeeded in emitting electrons from the body.

As a method of 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 (Patent Document 1), a method of patterning and etching a catalytic metal by a mask method ( There is a method (Patent Document 6) in which a substrate for CNT growth is covered with a photoresist mask and patterned by development and dissolution. 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-A-11-260249 JP 2000-340098 A Special table 2003-500325 gazette Special table 2003-500324 gazette JP 2002-338221 A JP 2001-020071 A 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 an image display apparatus using a field electron emission type cold cathode, it is advantageous to emit electrons with as low a 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 anode, the lower the voltage for extracting electrons. Therefore, if the height of the electron source is constant, the anode is placed close to the surface of the electron source. However, the uniformity of the distance can be maintained, and the extraction voltage can be lowered to obtain the same electron emission intensity.

  Further, the oriented CNT aggregate used for the field electron emission type cold cathode preferably has a smaller area. If the area of the oriented CNT aggregate is smaller, the electric field concentrates more strongly at the tip, so that the field emission capability is expected to be large. 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.

  In view of the above, the present invention patterns an oriented CNT aggregate having a small area, that is, a columnar aggregate of oriented CNTs, which is composed of CNTs having a vertical orientation, a constant height, and a small tube diameter. It is an object of the present invention to provide a method and a method for producing a field emission cold cathode that enables uniform electron emission at a low voltage by transferring the CNT aggregate to an electrode substrate.

As a result of intensive studies on a method of manufacturing a field emission cold cathode, the present inventors prepared an oriented CNT film having a uniform and constant height on a first substrate, and a plurality of second CNT films as a second substrate. Prepared by patterning an adhesive spot in an arbitrary position with a spot area of 0.01 mm ² or less and adhering the surface of the oriented CNT film on the first substrate onto the second substrate By overlapping the spots and peeling off the first substrate leaving only the alignment CNT film on the adhesion spot portion of the second substrate, there is vertical alignment on the second substrate and the height is constant. Orientable CNT aggregates with an area of 0.01 mm ² or less made of CNTs, that is, columnar aggregates of oriented CNTs can be patterned, and by using a conductive substrate as the second substrate, uniform at low voltage Easy electron emission It has reached the finding present invention a method of manufacturing a field emission cathode.
That is, the first of the present invention is a step of forming an oriented carbon nanotube film on the first substrate, and a plurality of adhesion spots on the second substrate with a single spot area of 0.01 mm ² or less. A step of forming a pattern at an arbitrary position, a step of adhering an adhesive spot on the second substrate on the surface of the oriented carbon nanotube film on the first substrate, and an oriented carbon adhered to the adhesive spot An alignment property characterized by forming a columnar aggregate formed by aggregating oriented carbon nanotubes at the adhesion spot on the second substrate through a step of peeling the nanotube from the first substrate. This is a method for producing a patterned columnar aggregate of carbon nanotubes.
The second aspect of the present invention is a method for manufacturing a field electron emission type cold cathode, wherein a conductive substrate is used as the second substrate, whereby patterned columns of oriented CNTs are formed on the electrode substrate. A method of manufacturing a field emission cold cathode, comprising forming a shape assembly.

  According to the method for producing a field emission cold cathode of the present invention, an electric field having an electron source in a unit of a columnar aggregate formed by assembling oriented CNTs having vertical alignment and uniform height and density. An emission type cold cathode 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 an image display device that operates at a low voltage and has uniform luminance.

In this embodiment, the first method for producing a patterned columnar aggregate of oriented carbon nanotubes according to the present invention is to prepare an oriented CNT film having a uniform and constant height on a first substrate. In addition, a plurality of adhesion spots, each having a spot area of 0.01 mm ² or less and patterned at an arbitrary position, are prepared as a second substrate, and the surface of the oriented CNT film on the first substrate is prepared. Adhesion spots on the second substrate are stacked and adhered, and the first substrate is peeled off leaving only the alignment CNT film on the adhesion spot portion of the second substrate, whereby the vertical alignment on the second substrate. This is a method of patterning oriented CNT aggregates having an area of 0.01 mm ² or less, ie, columnar aggregates of oriented CNTs.

  The oriented CNT film on the first substrate in the present invention is not particularly limited as long as it is uniform and has a constant height. However, when the CNT film is used as a field emission cold cathode, each CNT is It is desirable that the pipe diameter is as thin as possible. However, since single-walled CNT has a problem in strength, a multilayered CNT having two or more layers is desirable. In addition, the orientation CNT film on the first substrate is preferably weak in the adhesion between the first substrate and the CNTs on the substrate because an operation of peeling from the first substrate is performed later.

  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 JP-A-2002-338221, the CNT film is prepared by supporting a CNT-forming catalyst on a basic substrate prepared by vapor-depositing aluminum on a supporting substrate, It can be produced by decomposing a carbon compound on a substrate. In addition, as described in JP-A-2004-002182, the CNT film is formed on a basic substrate in which a sol-gel porous carrier having 0.1 to 50 nm pores on a supporting substrate is prepared. 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 substrate for CNT growth 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 production 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.

  As the first substrate used in the present invention, the basic substrate used for the production of the oriented CNT film can be used as it is. However, the base substrate is usually made of a non-deformable material such as ceramics or quartz. Therefore, when the second substrate is a material that cannot be deformed like the first substrate, it is difficult to uniformly contact the entire surface of the oriented CNTs on the first substrate with the second substrate. There is. As a means for compensating for this, an oriented CNT film transferred onto a deformable flexible substrate is preferably used. By using a deformable sheet, the surface of the oriented CNT film transferred to the flexible substrate and the non-deformable second substrate surface can be brought into uniform contact and adhere well Can do.

  The orientation CNT film on the flexible substrate is prepared by preparing an orientation CNT film on the base substrate and having a surface on which the surface of the orientation CNT film can be bonded and peeled off. After bonding, the base substrate is peeled off, leaving the oriented CNT film adhered to the surface that can be adhered and peeled, and the oriented CNT film is transferred. As a specific implementation method, the surface of the oriented CNT film grown on the base substrate is brought into contact with the surface of a flexible substrate made of a deformable sheet, followed by drying, pressure bonding, heating, or thermocompression bonding. The contact surface is adhered, and the oriented CNT film is peeled off from the base substrate to produce an oriented CNT film on the flexible substrate sheet.

  As the flexible substrate sheet used here, a flexible substrate having a surface that can be bonded and peeled can be used. The surface that can be bonded and peeled only needs to have weak adhesiveness or adhesiveness on the surface, and the adhesive or adhesive is applied to the entire surface of the sheet. In particular, a sheet printed with an EVA or acrylic adhesive is preferred. In addition, even a sheet that does not have adhesiveness or tackiness under a normal environment, or a sheet that exhibits adhesiveness or tackiness under a special environment such as a humid atmosphere or high temperature can be used. Specific examples of the flexible substrate include a single-layer sheet made of a thermoplastic resin, a two-layer structure sheet of an adhesive acrylic resin / thermoplastic resin, and an adhesive two-layer structure sheet of an adhesive EVA / thermoplastic resin. Examples of the thermoplastic resin include polyolefin, polyester, polycarbonate, polyamide, and polyimide. Moreover, the sheet | seat which consists of a thermosetting resin illustrated by an epoxy resin and a phenol resin, and the sheet | seat which consists of water-soluble resin illustrated by polyvinyl alcohol can also be used. When using a heat-adhesive binder in a later step, the sheet is preferably a sheet that can withstand the curing temperature. A multilayer sheet composed of two or more layers having a surface capable of bonding and peeling can also be used.

  In addition, after the surface of the alignment film transferred to the first flexible substrate is bonded to the surface of the flexible substrate having a second bondable and peelable surface, the bondable and peelable surface. Also preferred is a method of interposing a step of peeling the first flexible substrate leaving the oriented CNT film adhered to and transferring the oriented CNT film to the surface of the second flexible substrate. As the flexible substrate having the first and second adhesive and peelable surfaces, the same sheet as the flexible substrate having the adhesive and peelable surface can be used. It is preferable to use different types of sheets in order to increase the transferability by making a difference in the adhesiveness. The flexible substrate having a surface that can be peeled off and peeled is preferably a heat-resistant sheet that can withstand the curing temperature when a heat-adhesive binder is used in a later step.

An oriented CNT film on the first substrate was prepared by the above-described method, and a plurality of adhesion spots were formed as patterns on arbitrary positions with a spot area of 0.01 mm ² or less as the second substrate. The adhesive spot on the second substrate is overlapped and adhered to the surface of the oriented CNT film on the first substrate, and the oriented CNT film is left only on the adhesive spot portion of the second substrate. By exfoliating one substrate, an aligned CNT aggregate having an area of 0.01 mm ² or less, which is composed of CNTs having a vertical alignment and a constant height on the second substrate, that is, a column-shaped assembly of oriented CNTs The body can be patterned.
Here, various methods can be used as a method of patterning a plurality of adhesion spots on the second substrate at an arbitrary position with one spot area of 0.01 mm ² or less.

As a first method for patterning an adhesive spot at an arbitrary position, there is a method in which an adhesive binder is applied to an arbitrary position on the second substrate, and only the adhesive binder application portion is adhered. This is shown in FIG. Here, one spot area of the adhesive binder needs to be 0.01 mm ² or less. Examples of a method that enables such a coating pattern include a screen printing method, a dispenser method, and an ink jet method. The surface of the oriented CNT film on the first substrate is formed by using a second substrate in which an adhesive binder is applied to an arbitrary position at an arbitrary position with a spot area of 0.01 mm ² or less by these methods. By adhering to the second substrate, the CNT adheres only to the application part of the adhesive binder, and a pattern is formed at any position on the second substrate with a spot area of 0.01 mm ² or less. Can do. Note that CNT does not necessarily have to be attached to the entire surface of one spot of the adhesive binder, and may be attached to only a part of one spot. In that case, a columnar aggregate of oriented CNTs having a smaller area is preferable.

As a second method of patterning the adhesion spot at an arbitrary position, there is a method in which an adhesive binder is applied to a second substrate and a non-adhesive substance is disposed on the surface of the adhesive binder. As the shape and arrangement of the non-adhesive substance, a portion where the non-adhesive substance does not exist, that is, an adhesive spot may be formed at an arbitrary position with one spot area of 0.01 mm ² or less. This is shown in FIG. Examples of the shape of the non-adhesive substance include particles, scales, films, and plates. In the case of particles and scales, a smaller particle diameter is preferred. If it is too large, there is an obstacle to the adhesion of oriented CNTs. Further, patterning of 0.01 mm ² or less becomes difficult. The diameter is preferably 100 μm or less, more preferably 10 μm or less. Specific examples of the substance include metal particles, activated carbon, and carbon fiber. These particles are spread on an adhesive binder at an appropriate density. As an example of a specific method, the non-adhesive substance is spread on one surface of an adhesive binder, and the non-adhesive substance not adhered to the adhesive binder is shaken off. If it does in this way, the crevice between nonadhesive particles will certainly arise. This gap becomes an adhesion spot. There is also a method in which a non-adhesive substance is arranged through a mask in which one through-hole having a spot area of 0.01 mm ² or less is patterned. When the non-adhesive substance is in the form of a film or a plate, a material in which a plurality of through-holes each having an area of 0.01 mm ² or less are formed in advance is prepared. Examples of a method for forming such a through-hole pattern include a pressing method, a laser processing method, an electroforming method, and a photolithography method. By adhering CNTs with this film or plate placed on an adhesive binder, it is possible to adhere CNTs with a spot area of 0.01 mm ² or less. Therefore, a thinner plate or film is preferable. If it is too thick, the CNTs cannot contact the adhesive binder. The thickness is preferably 20 μm or less, more preferably 5 μm or less. By these methods, it is possible to selectively bond CNTs only to a portion where no non-adhesive substance exists. Moreover, these non-adhesive substances may be removed after the selective adhesion of the CNTs or may not be removed.

As a third method for patterning the adhesion spot at an arbitrary position, there is a method in which the surface of the second substrate is made uneven, and selectively adhered to the convex position. If the surface of the second substrate is uneven, the adhesive pressure is increased only at the convex portion when contacting the oriented CNT film on the first substrate, and only the convex portion is selectively bonded. Therefore, even if the adhesive binder is applied to the entire surface of the second substrate having an irregular shape, the oriented CNT film is selectively adhered only to the convex position. This is shown in FIG. In some cases, the adhesive binder is not applied to the concave position. At this time, in order to make the alignment CNT film adhesion portion of the second substrate one area of 0.01 mm ² or less, the area of one protrusion needs to be 0.01 mm ² or less. As a method for producing such a concavo-convex shape, a lithography method such as etching by electron beam, laser, chemicals, mechanical processing, or photolithography using a photosensitive material is usually performed. At this time, as the uneven step, it is only necessary to have a difference in bonding pressure when bonding CNTs. Preferably it is 100-1 micrometer, More preferably, it is 50-5 micrometers. These uneven shapes can be produced directly on the surface of the second substrate having adhesiveness, or after the surface of the second substrate is made uneven by these methods, an adhesive binder is applied to the entire surface. You can also. By these methods, selective adhesion of the oriented CNT film becomes more reliable.

Further, as a method for producing an easier uneven shape, there is also a method of arranging particles on the second substrate. As for the size of the particles, it is sufficient if there is a level difference that makes a difference in the adhesion pressure when the CNTs are adhered. The diameter is preferably 100 to 1 μm, more preferably 50 to 5 μm. Specific examples of the material include metal particles, activated carbon, carbon fiber, plastic pieces, and glass. When this is used for a field emission cold cathode, it is preferable to use conductive particles. By spreading these particles on the second substrate, convex patterning is possible with an area of 0.01 mm ² or less for each spot. As an example of a specific method, particles are spread on one surface on a substrate on which an adhesive binder has been entirely applied, and non-adhesive substances that have not adhered to the adhesive binder are shaken off. If it does in this way, the particle | grains which remain | survive will become convex. In addition, a method of arranging particles through a mask in which one spot area is 0.01 mm ² or less and through holes are patterned, or an adhesive binder is patterned on a second substrate, and the particles are placed on the adhesive binder. There is also a method of bonding. Examples of a method for forming such a through-hole pattern include a pressing method, a laser processing method, an electroforming method, and a photolithography method. Examples of the method for forming the adhesive binder pattern include a screen printing method, a dispenser method, and an ink jet method. By making the second substrate into an uneven shape by the above-described method and then applying an adhesive binder to the entire surface, the oriented CNT film can be selectively adhered to the position of the particles. As an example, FIG. 4 shows a method for producing a patterned columnar aggregate of oriented CNTs using a method in which an adhesive binder is patterned on a second substrate and particles are adhered to the adhesive binder. Show. In FIG. 4, one particle is disposed at one spot of the adhesive binder, but a plurality of particles may be disposed at one spot of the adhesive binder. By this method, an oriented CNT film can be adhered more easily and more reliably to a large area.

By the above-described method, a plurality of adhesion spots are patterned on the second substrate at an arbitrary position with a spot area of 0.01 mm ² or less, and the oriented CNT film on the first substrate is bonded to the adhesion spot. By bonding to, a patterned columnar aggregate of oriented CNTs having a spot area of 0.01 mm ² or less can be formed on the second substrate. Here, the area of one adhesion spot is preferably as small as 0.01 mm ² or less. In particular, when it is used as a cold cathode for field emission, the smaller one is preferable. Preferably, 0.01 mm ² or less, more preferably 0.0001 mm ² or less.

  Subsequently, a method for producing a field emission cold cathode, characterized by using a patterned columnar oriented CNT aggregate produced by the first method of the invention, which is the second of the present invention, is described. To do. First, in manufacturing a field emission cold cathode, a conductive substrate is used as the second substrate. Usually, since an electroconductive board | substrate does not have adhesiveness, it is necessary to apply | coat an adhesive binder to an electroconductive board | substrate. In addition, since the bonded columnar aggregate of oriented CNTs and the conductive substrate must be energized, it is preferable to use a conductive binder as the adhesive binder.

  As the conductive binder used here, a conductive paste is preferably used because fine patterning is required in the first method of the present invention. As the conductive paste used in the present invention, a conductive silver paste, a conductive gold paste, a conductive carbon paste, or a conductive copper paste is preferably used because of its conductivity and processing performance.

The field emission cold cathode manufactured by the above-described method is uniform because the tip surface of the CNT aggregate patterned on the conductive substrate is parallel to the electrode surface and smooth, and the height is constant. Enables light emission. Moreover, since the area of one columnar aggregate of oriented CNTs is as small as 0.01 mm ² , it has a large field emission capability.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
Example 1
(Preparation of oriented CNT film on first substrate)
As a support substrate, a square silica alumina plate having a composition of 25% silica and 75% alumina and a thickness of 2 mm and a side of 30 mm was used, and aluminum was coated to a thickness of 0.13 μm by vacuum deposition to obtain a basic substrate. It was. Next, it was immersed in a cobalt nitrate aqueous solution having a concentration of 0.2 mol / l for 10 minutes. The substrate was pulled up and then fired in the air at 400 ° C. for 3 hours to obtain a substrate for CNT growth. After firing, the CNT growth substrate was placed in a quartz tube furnace with the aluminum deposition side facing up horizontally. The temperature of the tubular furnace was increased to 700 ° C. while supplying argon at 360 ml / min in the horizontal direction. Subsequently, while maintaining the temperature at 700 ° C., propylene was mixed at a rate of 120 ml / min with 360 ml / min of argon, and the mixture was fed into the tubular furnace. After flowing a propylene / argon mixed gas for 8 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 50 μm was formed on the upper side of the basic substrate.
The film is made of CNTs oriented in the vertical direction, and has 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.
Next, the surface of the oriented CNT film is brought into contact with the surface of a water-soluble sheet (first flexible substrate) made of polyvinyl alcohol that has been preliminarily wetted in an atmosphere of 30 ° C. and 80% humidity for 2 hours. And crimped over 2 MPa. After crimping and drying, the water-soluble sheet was pulled to leave the oriented CNT film, and the basic substrate was peeled off to produce an oriented CNT film on the surface of the water-soluble sheet. Further, the surface of the oriented CNT film transferred to the water-soluble sheet is brought into contact with the surface of the adhesive sheet (second flexible substrate) made of an adhesive acrylic resin / polyolefin, and is pressed with a press machine at 2 MPa. did. After crimping, the entire sample is placed in a 90% humidity atmosphere for 1 hour, the water-soluble sheet is moistened and peeled off from the oriented CNT film to produce an oriented CNT film on the surface of the adhesive sheet. An oriented CNT film was prepared on the substrate.
(Transfer to the second substrate)
A conductive substrate was prepared by depositing aluminum on a 2.5 cm * 7.5 cm glass plate to form a conductive layer. A conductive silver paste was screen-printed on the surface of the conductive layer using a single screen plate having a spot diameter of 10 μm or less. As a result, the conductive silver paste was patterned with a diameter of 18 μm and a thickness of 5 μm. Here, the surface of the produced oriented CNT film and the screen-printed conductive silver paste were brought into contact on an adhesive sheet, pressed at 8.0 MPa, and then heated to 100 ° C. in an argon atmosphere. After cooling, the adhesive sheet was peeled off while leaving the oriented CNT film adhered to the conductive silver paste to obtain a field emission cold cathode to which the patterned columnar aggregate of oriented CNT was transferred. . FIG. 5 shows an SEM image of the columnar oriented CNT pattern.
The results of field electron emission measurement as a cathode are shown in FIG. The horizontal axis represents the electric field V / μm, and the vertical axis represents the current density mA / cm ² .

Example 2
(Preparation of oriented CNT film on first substrate)
The oriented CNT film on the first substrate was produced in the same manner as in Example 1.
(Transfer to the second substrate)
A conductive substrate was prepared by depositing aluminum on a 2.5 cm * 7.5 cm glass plate to form a conductive layer. Using a dispenser, a conductive silver paste was patterned on the surface of the conductive layer with a spot diameter of 100 μm. Here, the surface of the prepared oriented CNT film and the conductive silver paste patterned with a dispenser were brought into contact with the adhesive sheet, pressed at 2.0 MPa, and then heated to 150 ° C. in an argon atmosphere. After cooling, the field emission in which the patterned columnar aggregate of oriented CNTs is adhered onto the conductive silver paste by peeling the adhesive sheet leaving the oriented CNT film adhered to the conductive silver paste A mold cold cathode was obtained.
The results of field electron emission measurement as a cathode are shown in FIG.

Example 3
(Preparation of oriented CNT film on first substrate)
The oriented CNT film on the first substrate was produced in the same manner as in Example 1.
(Transfer to the second substrate)
A conductive substrate was prepared by depositing aluminum on a 2.5 cm * 7.5 cm glass plate to form a conductive layer. A conductive silver paste having a thickness of 15 μm was screen-printed on the surface of the conductive layer, and nickel particles having a diameter of 5 μm were spread over the conductive silver paste. Here, the surface of the prepared oriented CNT film and the conductive silver paste in which nickel particles were spread were brought into contact with the adhesive sheet, pressed at 2.0 MPa, and then heated to 150 ° C. in an argon atmosphere. After cooling, the field emission type in which the aligned columnar aggregate of oriented CNTs is adhered to the gaps between nickel particles by peeling the adhesive sheet leaving the oriented CNT film adhered to the conductive silver paste A cold cathode was obtained.
The results of field electron emission measurement as a cathode are shown in FIG.

Comparative Example 1
(Preparation of oriented CNT film on first substrate)
The oriented CNT film on the first substrate was produced in the same manner as in Example 1.
(Adhesion to the second substrate)
An electrode substrate having a conductive layer formed on a glass plate was prepared. A conductive silver paste was screen-printed with a thickness of 15 μm on the surface of the conductive layer. Here, the surface of the produced oriented CNT film and the screen-printed conductive silver paste were brought into contact on an adhesive sheet, pressed at 2.0 MPa, and then heated to 150 ° C. in an argon atmosphere. After cooling, the adhesive sheet was peeled off while leaving the oriented CNT film adhered to the conductive silver paste to obtain a field emission cold cathode having the oriented CNT film transferred thereto.
The results of field electron emission measurement as a cathode are shown in FIG.

  In each example, constant field electron emission was uniformly obtained with a relatively low applied voltage. On the other hand, in the comparative example, a relatively high applied voltage was required to obtain constant field electron emission.

Method for producing patterned columnar aggregate of oriented CNTs by patterning application of adhesive binder Method for producing patterned columnar aggregate of oriented CNTs by patterning non-adhesive material Method for producing patterned columnar aggregate of oriented CNTs by patterning of irregularities Method for producing patterned columnar aggregate of oriented CNTs by patterning arrangement of particles SEM photograph of patterned columnar aggregate of oriented CNT Field electron emission measurement results

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st base | substrate 2 Oriented CNT film | membrane 3 2nd base | substrate 4 Column-shaped oriented CNT aggregate 5 Adhesive binder 6 Non-adhesive substance 7 Convex part 8 Particles

Claims (9)

A step of forming an oriented carbon nanotube film on the first substrate, and a step of patterning a plurality of adhesion spots on the second substrate at an arbitrary position with a spot area of 0.01 mm ² or less. A step of superposing and adhering the adhesion spot on the second substrate on the surface of the oriented carbon nanotube film on the first substrate, and peeling off the oriented carbon nanotube adhered to the adhesion spot from the first substrate. In a method for producing a patterned columnar aggregate of oriented carbon nanotubes, a columnar aggregate is formed by gathering oriented carbon nanotubes at the adhesion spot on a second substrate through a process. there, the method of patterning an adhesive spot to an arbitrary position, Ru method der to place non-adhesive material to a second substrate surface coated with adhesive binder Method for producing a patterned column-shaped aggregate distribution tropic carbon nanotubes. A step of forming an oriented carbon nanotube film on the first substrate, and a step of patterning a plurality of adhesion spots on the second substrate at an arbitrary position with a spot area of 0.01 mm ² or less. A step of superposing and adhering the adhesion spot on the second substrate on the surface of the oriented carbon nanotube film on the first substrate, and peeling off the oriented carbon nanotube adhered to the adhesion spot from the first substrate. In a method for producing a patterned columnar aggregate of oriented carbon nanotubes, a columnar aggregate is formed by gathering oriented carbon nanotubes at the adhesion spot on a second substrate through a process. The method of forming an adhesive spot pattern at an arbitrary position is to apply an adhesive binder on the surface of the second substrate having an arbitrary uneven shape, and Method for producing a patterned column-shaped aggregate distribution tropic carbon nanotube you characterized by bonding the aligned carbon nanotube film surface on the first substrate selectively to the position of the convex surface. The method for producing a patterned columnar aggregate of oriented carbon nanotubes according to claim 1 or 2, wherein one spot area of the adhesion spot is 0.0001 mm ² or less. 3. The method for producing a patterned columnar aggregate of oriented carbon nanotubes according to claim 2 , wherein the method of forming the second substrate with an uneven shape is etching or lithography of the second substrate. 3. The oriented carbon nanotube according to claim 2 , wherein the method of forming the second substrate with an uneven shape is a method in which particles are arranged at arbitrary positions on the second substrate and the particle portions are made convex. A method for producing a patterned columnar assembly. The method for producing a patterned columnar aggregate of oriented carbon nanotubes according to any one of claims 1 to 5 , wherein the first substrate is a flexible substrate. The second substrate is a conductive electrode substrate, the adhesive binder is a conductive paste, and the oriented carbon nanotubes formed on the electrode substrate by the method according to any one of claims 1 to 6 are patterned. Of manufacturing a field emission cold cathode using a cylindrical aggregate. 8. The method of manufacturing a field emission cold cathode according to claim 7 , wherein the conductive paste is a conductive silver paste, a conductive gold paste, a conductive carbon paste, or a conductive copper paste. A field emission cold cathode produced by the method according to claim 7 or 8 .

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