JP2005032523A - Electron emission element and display device using the same, and method of manufacturing electron emission element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method which very easily manufactures an electron emission element, using a carbon nanotube (CNT) superior in electrical and mechanical properties. <P>SOLUTION: Two substrates 5 (5a, 5b) are separated from each other. As the two substrates 5 separate from each other, a plurality of CNTs 2 in line segments are made to arrange in a state of standing erect on the surfaces of the substrates 5 in unison. A paste material 3 is solidified to be used as a support. The support supports the CNTs 2, in a state of standing erect. This forms a bunch of CNTs used as the electron emission element and the like. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electron-emitting device suitable for, for example, a triode field effect display device, a manufacturing method thereof, and a display device (display) using the electron-emitting device.
[0002]
[Prior art]
In recent years, field emission display (FED) devices including electron-emitting devices have been developed in particular in terms of characteristics such as image display brightness, color reproducibility, wide viewing angle, and low power consumption. The device is attracting attention as a device for a next-generation flat panel display device suitable for a wall-mounted television or the like (see, for example, Patent Documents 1 to 14).
[0003]
In general, as a technique of FED, a technique using a Spindt-type emitter in which Mo (molybdenum) is formed in a pointed shape by a vapor deposition method in an emitter well patterned in advance has been proposed. .
[0004]
Until the first FED prototype (prototype) was announced (around 1985), practically no practical study was made on such FED, but after the prototype was announced, Research and development has been actively promoted, and a prototype of full-color VGA specifications with a diagonal of 15 inches (about 38.1 [cm]) has been announced.
[0005]
[Patent Document 1]
JP 2003-141983 A
[Patent Document 2]
JP 2003-151456 A
[Patent Document 3]
JP 2003-115259 A
[Patent Document 4]
JP 2003-115257 A
[Patent Document 5]
JP 2003-123632 A
[Patent Document 6]
JP 2003-86079 A
[Patent Document 7]
JP 2003-86085 A
[Patent Document 8]
JP 2003-86080 A
[Patent Document 9]
JP 2003-7196 A
[Patent Document 10]
JP 2003-7200 A
[Patent Document 11]
JP 2003-7234 A
[Patent Document 12]
JP 2002-197965 A
[Patent Document 13]
JP 2002-150922 A
[Patent Document 14]
JP 11-329217 A
[Non-Patent Document 1]
Huang et al. , Large-scale routed growth of aligned super bundles of single-walled carbon nanotubes using a directed arc plasma method, “Chemical 34”, “Chem. 7-14
[0006]
[Problems to be solved by the invention]
Various conventional prototypes and research for the practical application of the FED including the prototype as described above can sufficiently satisfy the conditions for practical use in terms of display image quality and manufacturing cost. Such technology has not yet been achieved.
[0007]
The most important problems in achieving the practical use of FEDs are the phosphor problem applicable to display devices operating at a low anode voltage or discharge voltage of less than 1 [kV], the visibility of spacers, etc. Problems include cathode durability (lifetime) issues in display devices that operate at high anode voltages.
[0008]
As an approach different from the above for the practical application of the FED, a technique for uniformly producing a Spindt type electron-emitting device (emission cathode) over a large area has been tried. The technical approach greatly relates to the cost of the vapor deposition method for forming the electron-emitting device and the elimination of the complexity of the process.
[0009]
However, even if any of the above approaches succeeded in the past for practical application of FED, and FED up to about 15 inches diagonally has been put into practical use by that technology, for example, In order to achieve the practical use of FEDs with larger screens, the higher aspect ratio, conductivity, thermal resistance, and mechanical strength, which are different from those used in the prior art as described above, are required. It is necessary to realize an emitter made of the provided material.
[0010]
Accordingly, it has been proposed to produce a flat panel display device using CNTs by paying attention to various effectiveness of carbon nanotubes (CNT; Carbon Nanotubes; hereinafter, carbon nanotubes are also referred to as CNTs). In recent years, attention has been paid to the tripolar cathode structure (gated cathode structure) as an indispensable part of its main technology, including a completely sealed 4.5 inch, 3 color, nanotube FED, and 4.5 inch.・ Prototypes such as full-color nanotube FED or 9-inch full-color nanotube FED with 576 × 242 pixels have been made. Further, a nanotube FED having a diagonal size of 32 inches has been experimentally produced.
[0011]
As a method for manufacturing an electron-emitting device (emitter) using CNT, the following two types are mainly proposed.
[0012]
One of them is that a vertical hole (cathode hole) is formed in advance in a substrate having a gate electrode layer, and CNT as an emitter is directly generated in this cathode hole by a CVD method. The other is to fill the cathode hole with a mixture of CNTs in a vehicle made of an organic material.
[0013]
Of the above manufacturing methods, it has been reported that an emitter array (FEA; Field Emission Array) can be manufactured and functioned effectively by the CVD method. The FEA was manufactured at a temperature (600 ° C. or higher) that is extremely high (too high) as the temperature at which FEA is formed on a glass substrate. Have been reported to be made as a well-ordered array.
[0014]
However, such a CVD method has a problem that it is difficult to produce a uniform FEA over a large area. In addition, there is a problem that it is difficult to adjust the length and density of CNTs to be appropriate and to make the length and density uniform.
[0015]
On the other hand, among the above manufacturing methods, a manufacturing method in which a cathode hole is filled with a mixture of CNTs in a vehicle made of an organic material, and a uniform FEA can be manufactured over a large area. Since it is expected that it is relatively easy to adjust the length and density of CNTs to appropriate values, it is considered to be a promising technique. Actually, trial production of a gate CNT-FEA having a performance capable of displaying a moving image of a color image by using this technique has been performed.
[0016]
Trial production of tripolar CNT-FED has also been attempted by screen printing using backside lithography (backside exposure technology).
[0017]
In this manufacturing method, as a material for forming FEA, a material obtained by mixing CNT into a photoreactive paste, printing it in a predetermined pattern by a screen printing method, and curing it is used. However, in this method, therefore, only weak ultraviolet light is exposed near the outermost surface farthest from the bottom surface, and as a result, the paste near the outermost surface peels off during development of the photoreactive paste, and the portion There is a fundamental problem due to the use of the backside exposure technology that causes defects.
[0018]
In addition, in order to display a high-quality image of a full-color image, it is required that the emitter be precisely manufactured. In order to satisfy the above-described conventional technique, the following is required. There are problems to be solved.
[0019]
That is, firstly, the composition of the paste material mixed with CNTs is often non-uniform, so that the characteristics of the emitter array formed using the same are also non-uniform, thereby improving the image quality. There is a problem of lowering.
[0020]
Second, since the orientation and length of the emitter CNT provided on the substrate are not sufficiently aligned, there is a problem that the display characteristics within one screen become non-uniform.
[0021]
Third, in the vapor deposition process of the photoreactive material, there is a possibility that components used during the vapor deposition may contaminate or damage the CNT, which causes a problem that the shape reproducibility and reliability of the emitter are lowered.
[0022]
Fourth, since the binder, printing filler, photoreactive material, and the like mixed in the photoreactive paste for backside exposure are further mixed with CNT, they adversely affect the performance of the CNT as an emitter. It will be. In addition, this adversely affects the performance as a CNT-FED device, and further deteriorates the shape reproducibility and reliability of the emitter, thereby degrading the image display quality of the FED equipped with the emitter. There is a problem.
[0023]
Fifth, most of the CNTs are buried in the paste material, and only a small number of CNTs stand up and protrude from the surface of the paste material in many cases. Cannot be concentrated, and as a result, the brightness and clarity of the display image cannot be made sufficient.
[0024]
The present invention has been made in view of such problems, and a first object is to solve the above-described problems and to perform uniform and high-quality image display by a very simple and reliable method. The object is to provide a method for manufacturing an electron-emitting device.
[0025]
The second object of the present invention is manufactured by the above-described manufacturing method of the present invention, and is supported in an upright posture with cylindrical carbon molecules aligned, and has high shape reproducibility and reliability, uniform and high display quality. It is an object to provide a high-performance electron-emitting device capable of performing display and a display device using the same.
[0026]
[Means for Solving the Problems]
The electron-emitting device according to the present invention has one or a plurality of cylindrical carbon molecules standing on a substrate. Here, the “tubular carbon molecule” includes single-walled carbon nanotubes, multi-walled carbon nanotubes, carbon nanofibers, and carbon nanohorns. Here, the standing state is a state in which one end of the cylindrical carbon molecule extending in the longitudinal direction is disposed in the vicinity of the surface of the substrate, and the other end of the cylindrical carbon molecule is positioned further away from the surface of the substrate. Say.
[0027]
The display device according to the present invention includes an electron-emitting device having one or more cylindrical carbon molecules standing on a substrate, a predetermined voltage applied to the cylindrical carbon molecules, and electrons from the cylindrical carbon molecules. It has a configuration including an electrode to be emitted and a fluorescent part that emits light upon receiving electrons emitted from the electron-emitting device.
[0028]
The method for manufacturing an electron-emitting device according to the present invention includes a mixing step in which a cylindrical carbon molecule and a material having a predetermined viscosity are mixed to produce a coating material, and the coating material is selected from the first substrate and the second substrate. An application step of applying to at least one of the first substrate, an adhesion step of bringing the first substrate and the second substrate into close contact via a coating material, and the first substrate and the second substrate to each substrate surface And an element forming step for raising the cylindrical carbon molecules by pulling them apart in a substantially vertical direction.
[0029]
In the electron-emitting device according to the present invention, electrons are emitted in the extending direction from cylindrical carbon molecules standing on the substrate. Therefore, in the display device of the present invention using a plurality of such electron-emitting devices, uniform and high-quality image display is performed.
[0030]
In the method for manufacturing an electron-emitting device according to the present invention, in the mixing step, cylindrical carbon molecules and a material having a predetermined viscosity are mixed to produce a coating material. Next, in a coating process, a coating material is applied to at least one of the first substrate and the second substrate. Subsequently, in the adhesion process, the first substrate and the second substrate are adhered to each other through the coating material. After that, in the element formation process, the first substrate and the second substrate are separated in a substantially vertical direction with respect to each substrate surface, whereby the coating material is deformed in a viscous manner, and the viscosity of the coating material is increased. The material having the shape is constricted near an intermediate position between the two substrates. Due to the viscous flow effect accompanying the viscous deformation of the viscous material, the two substrates have been lying or folded in a horizontal or oblique direction with respect to the substrate surface. A plurality of cylindrical carbon molecules that are in a bent state or a curved state are aligned in such a manner that they rise from the surface of the substrate all at once. When the substrate is further pulled away to a sufficient distance, the viscous material gradually narrows near the middle position between the two substrates, and eventually exceeds the limit of viscous flow deformation. It is separated in a state of being cut at that part. At this time, a plurality of cylindrical carbon molecules are erected and attached in the same direction on each of the surfaces of the two substrates. Thereby, the electron-emitting device of the present invention is manufactured.
[0031]
In addition, the cylindrical carbon molecule which became the standing state is supported in the state which stood on the board | substrate with the support member by solidifying the support member which consists of a material which has viscosity.
[0032]
Further, the support member made of a material having viscosity is formed into a shape in which a rough shape protrudes in a pointed manner on the substrate by cutting the substrate by separating the substrate as described above. Therefore, the shape of the tip portion of the emitter composed of the tips of the plurality of cylindrical carbon molecules supported by it is also a shape protruding in a pointed shape. This concentrates the electric field more effectively. That is, the emitter having such a preferable shape can be formed extremely easily without requiring a complicated processing method.
[0033]
Further, by providing a protrusion with a flat upper surface on the surface of the substrate and providing the cylindrical carbon molecule in an upright state on the flat upper surface, the overall shape of the electron-emitting device can be reduced by an electric field. It is possible to concentrate more effectively.
[0034]
A manufacturing method in which a protrusion having a flat upper surface is provided on the surface of such a substrate and cylindrical carbon molecules are provided on the flat upper surface in a standing state is a so-called cathode such as a triode field effect display device. This is particularly suitable for an FED in which an emitter is provided on the bottom of a well (vertical hole).
[0035]
In addition, although the cylindrical carbon molecule provided in the standing state on the board | substrate can be one, it cannot be overemphasized that it is more desirable that it is multiple.
[0036]
In addition, it is desirable that the support member has conductivity required for an electron-emitting device. This is because current flows between the cylindrical carbon molecule and the substrate via the support member, so even if the conductivity in the cylindrical carbon molecule is good, the conductivity of the support member connecting the substrate and the substrate is low. This is because there is a possibility that the good conductivity of the bent cylindrical carbon molecule cannot be utilized.
[0037]
Further, after the cylindrical carbon molecules are raised from the respective surfaces of the two substrates, the raised cylindrical carbon molecules are bonded to both of the two substrates, or deliberately. If it is desired that the long cylindrical carbon molecules are erected in advance and then trimmed to the desired length, the erected cylindrical carbon molecules are cut between two substrates. By further including the step of performing, the cylindrical carbon molecules in an upright state may be trimmed to a uniform length. By doing so, a cylindrical carbon molecule having a uniform length and an electron-emitting device having a uniform performance are realized.
[0038]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0039]
FIG. 3 shows a main part of the electron-emitting device according to the embodiment of the present invention. This electron-emitting device is provided, for example, on a substrate 5 in a state where a plurality of cylindrical carbon molecules, for example, CNT (carbon nanotubes) 2 pulverized to a length within a predetermined range are erected. . These CNTs 2 are all standing up from the surface of the substrate 5, that is, in a forested state, and are supported upright on the substrate 5 by the support member 30 made of a solidified material. Yes.
[0040]
In the following description, a case where single-walled carbon nanotubes (SWCNT) or multi-walled carbon nanotubes (MWCNT) are used as cylindrical carbon molecules will be described. However, it is also possible to use carbon nanofiber (CNF) or carbon nanohorn, for example.
[0041]
CNTs generally have excellent mechanical and electrical properties. For example, single-walled carbon nanotubes (SWCNT) have a tensile strength 100 times that of steel (or 2 orders of magnitude greater) and a conductivity that is 100 times that of copper (or 2 orders of magnitude greater). In addition to SWCNTs, including multi-walled carbon nanotubes (MWCNTs), CNTs generally have a high aspect ratio and an extremely thin diameter, so that the electric field is concentrated at the tip. The function is excellent. Also, the carbon nanofiber (CNF) is larger than the CNT in terms of the scale of the outer diameter, but the mechanical characteristics and the electrical characteristics are substantially the same as those of the CNT. Therefore, CNT or CNF is extremely suitable as a material applied to an electron-emitting device that can be driven at a low voltage.
[0042]
The substrate 5 (5a, 5b) is made of, for example, glass, and an electrode 1 (1a, 1b) is formed on the surface thereof.
[0043]
The support member 30 is made of an organic material such as polyvinyl alcohol. Moreover, it is preferable that the support member 30 has conductivity that can satisfy the performance required as an electron-emitting device. Since a current flows between the CNT 2 and the electrode 1 of the substrate 5 through the support member 30, even if the conductivity of the CNT 2 is good, if the conductivity of the support member 30 that connects it to the substrate 5 is low, This is because the good conductivity of CNT2 may not be utilized.
[0044]
For example, carbon particles may be mixed in the support member 30 in order to increase conductivity. The carbon fine particles are not particularly limited, and examples thereof include carbon black, carbon microspheres, and carbon fibers. The carbon fine particles preferably have a size in the range of 1 [nm] to 1000 [μm], and more preferably have a size in the range of 1 [nm] to 100 [μm]. preferable. This is because, if the carbon fine particles become extremely large, for example, about 1000 times the diameter of the CNT 2, the carbon fine particles cover the CNT 2 in the manufacturing method described later, and it becomes difficult to make the CNT 2 stand up. Here, the “size” means the average particle diameter when the carbon fine particles are spherical, the thickness when they are flakes or rocks, and the fiber diameter when they are fibrous. .
[0045]
Alternatively, the support member 30 may be mixed with, for example, metal fine particles in order to increase conductivity. The metal fine particles are not particularly limited. For example, Ti (titanium), Mo (molybdenum), W (tungsten), Fe (iron), Co (cobalt), Ni (nickel), Cu (copper), Au (gold) It is possible to use suitably the thing which consists of 1 type or multiple types of IVa-Ib metals containing). The metal fine particles preferably have a size in the range of 1 [nm] to 1000 [μm], and more preferably have a size in the range of 1 [nm] to 100 [μm]. preferable. The reason is the same as in the case of carbon fine particles. Here, the “size” refers to the average particle diameter of the metal fine particles.
[0046]
Further, the support member 30 may be made of a material containing a conductive polymer, for example. Although it does not specifically limit as a conductive polymer, For example, what contains 1 type or multiple types of poly-P-phenylene vinylene (PPV), polyaniline, polythiophene, and polyacetylene is suitable.
[0047]
Furthermore, the support member 30 may be made of a material containing a conductive metal oxide, for example. Although it does not specifically limit as a conductive metal oxide, For example, what contains 1 type or multiple types of a tin oxide, a titanium oxide, and an indium oxide is suitable.
[0048]
The addition amount of these conductive substances contained in the support member 30 can be appropriately adjusted in consideration of the viscosity as the coating material 40 described later and the conductivity required for the support member 30.
[0049]
The support member 30 may be made of a material to which a conductive material as described above is added, or the support member 30 itself may be made of a conductive material.
[0050]
Such an electron-emitting device can be manufactured, for example, as follows.
[0051]
First, CNT2 is produced. SWCNT and MWCNT can be generally obtained by various production methods such as arc discharge method, laser ablation method, CVD method, etc. However, CNT2 produced by the arc discharge method has a characteristic of high heat resistance. Since this is a characteristic suitable as a CNT used for manufacturing an electron-emitting device, SWCNT2 manufactured by this arc discharge method is used in this embodiment.
[0052]
SWCNT2 is manufactured by direct current arc plasma discharge in a high vacuum chamber (not shown). In the manufacturing process of SWCNT2 by this direct-current arc plasma discharge, for example, a graphite rod (not shown) to which a lanthanide such as Co (cobalt), Ni (nickel), La (lanthanum) or the like is added as a catalyst is used as an anode for plasma discharge. It is possible to use a single graphite rod (not shown) as the cathode. In order to obtain SWCNT2 having higher oxidation resistance, it is desirable to use a ball-shaped cathode (not shown). For the process itself for producing such SWCNT2, for example, the technique proposed by the present inventors in Non-Patent Document 1 can be suitably used.
[0053]
Further, for example, by mixing an organic material such as polyvinyl alcohol and a solvent, a material 3 (hereinafter referred to as “paste material”) 3 having a predetermined viscosity is produced. The solvent is for adjusting the viscosity of the paste material 3 and is not particularly limited as long as it has volatility. In this embodiment, for example, water is used as the solvent. The viscosity of the paste material 3 is a viscosity that does not flow when applied to the surface of the substrate 5 and does not deform the substrate 5 when the substrate 5a and the substrate 5b are separated as will be described later. A viscosity range of about is desirable. Further, when the micromesh 4 is used as will be described later, it is desirable that the viscosity is lower so as not to cause deformation of the micromesh 4.
[0054]
Next, the SWCNT 2 is mixed with the paste material 3 to produce the coating material 40. The SWCNT 2 may be mixed with the paste material 3 without removing impurities or the like (it goes without saying that impurities may be removed). Furthermore, the obtained coating material 40 may be added to the obtained coating material 40 as necessary, for example, a solidification accelerator, or the above-described carbon fine particles, metal fine particles, conductive polymer, or conductive metal oxide particles (hereinafter referred to as “carbon fine particles”). ) Is then applied to a ball mill device (ball-shaped pulverizing and mixing device) to pulverize SWCNT 2 into a plurality of shorter line segments and to uniformly disperse SWCNT 2 in paste material 3. . After that, the coating material 40 is filtered with a filter to remove carbon fine particles of 5 [μm] or more.
[0055]
Subsequently, as shown in FIG. 1, two substrates 5 (5a, 5b) each having an electrode 1 (1a, 1b) formed on the surface thereof are prepared, and one or both of these substrates 5 are coated. Material 40 is applied. Then, these substrates 5 are arranged so that the electrodes 1 face each other with the coating material 40 in between, and then, by applying an appropriate pressing force from the outside to the two substrates 5, The coating material 40 is brought into close contact with the electrodes 1 on the respective surfaces of the two substrates 5.
[0056]
After that, as shown in FIG. 2, mechanical force is applied from the outside to separate the two substrates 5 sandwiching the coating material 40 from each other. Then, as the two substrates 5 are separated from each other, the coating material 40 (particularly, the paste material 3 among them) is viscously deformed, and the paste material 3 starts from the middle position between the two substrates 5. The condition becomes constricted.
[0057]
By the viscous flow action accompanying the viscous deformation of the paste material 3, the two substrates 5 are in a state of lying in a horizontal direction or an oblique direction with respect to the surface of the respective substrates 5 until then. A plurality of line-shaped CNTs 2 that are bent, bent, or curved are aligned to stand up with respect to the surface of the substrate 5 all at once.
[0058]
When the two substrates 5 are further separated to a sufficient distance, the constriction of the paste material 3 gradually decreases in the vicinity of the intermediate position between the two substrates 5 and eventually exceeds the limit of viscous flow deformation. So it is divided into two parts. Thus, as shown in FIG. 3, the plurality of CNTs 2 are attached in a state where they are erected in the same direction on each of the surfaces of the two substrates 5.
[0059]
After that, the support member 30 is formed by solidifying the paste material 3. As a result, the CNTs 2 in the upright state are supported by the support member 30 in the upright state on the substrate 5 (continuously as shown in FIG. 3). The solidification method of the paste material 3 may be selected according to the material of the paste material 3. For example, if the paste material 3 is thermosetting, it can be solidified by heating. Alternatively, if the paste material 3 is ultraviolet (UV) curable, it can be solidified by ultraviolet irradiation. The paste material 3 may be solidified by natural drying.
[0060]
FIG. 5 shows another electron-emitting device of the present embodiment. This electron-emitting device is the same as the electron-emitting device shown in FIG. 3 except that the support member 30 has a pointed protruding shape on the substrate 5. Such an electron-emitting device in which the support member 30 has a pointed protrusion shape is preferable because the electric field is more effectively concentrated.
[0061]
Such an electron-emitting device can be manufactured by using a paste material 3 having a higher viscosity than that used in the manufacturing method shown in FIGS.
[0062]
That is, when the viscosity of the paste material 3 is increased, when the two substrates 5 are separated by applying a mechanical force from the outside as in the case shown in FIGS. As shown in FIG. 4, the paste material 3 has a shape in which the rough shape protrudes like a peak on the substrate 5, and the shape of the tip of the emitter composed of the tips of a plurality of CNTs 2 supported by the paste material 3. Also has a shape protruding in a pointed shape.
[0063]
When the two substrates 5 are further separated to a sufficient distance, the limit of viscous flow deformation is eventually exceeded, and the paste material 3 is divided into two at that portion. After being divided into two, the height of the pointed tip of the paste material 3 on the individual substrate 5 is slightly lowered due to the surface tension of the paste material 3 itself, and the tip of the CNT 2 goes out from the surface. Will protrude. In this manner, an electron-emitting device in which the CNT 2 is supported at the tip of the support member 30 having a pointed protrusion shape as shown in FIG. 5 is formed.
[0064]
FIG. 8 shows still another electron-emitting device of the present embodiment. In this electron-emitting device, for example, when the length of each individual CNT2 is longer than a desired length, or when the long CNT2 is erected in advance, a desired length is obtained. It is something that has been trimmed to. Thereby, it is possible to realize a CNT 2 having a uniform length and an electron-emitting device having a uniform performance.
[0065]
This electron-emitting device allows the CNT 2 to pass through efficiently and also has a micro mesh (fine lattice) 4 (4a, 4b) having a lattice size capable of holding the surface of the paste material 3 flat (uniformly). It is preferable to provide.
[0066]
The material of the micromesh 4 is not limited to a conductor but may be an insulator, and examples thereof include stainless steel, ceramics, and plastic. Moreover, the diameter of the holes of the micromesh 4 is preferably larger than the diameter of the CNTs 2 so that the carbon fine particles mixed in the paste material 3 do not pass through the holes of the micromesh 4. For example, a range of 1 [nm] to 100 [μm] is suitable, but can be appropriately selected according to the size of the carbon fine particles and the diameter of the CNT 2. If the pore diameter of the micromesh 4 is selected within such a range, the CNTs 2 are erected by passing through the pores of the micromesh 4 while confining the carbon fine particles or the like in the paste material 3 without taking out from the pores of the micromesh 4. Can be in a state.
[0067]
Next, a method for manufacturing an electron-emitting device using such a micromesh 4 will be described with reference to FIGS. First, as shown in FIG. 6, the micro meshes 4a and 4b were buried in the paste material 3 mixed with the longer CNT 2 so that the surfaces facing each other were substantially parallel to each other, as shown in FIG. Thus, the board | substrate 5a and the board | substrate 5b are moved to the direction which spaces apart. At this time, as shown in FIG. 7, the CNT 2 is moved to 2 by keeping the positional relationship between the substrate 5a and the micromesh 4a and the positional relationship between the substrate 5b and the micromesh 4b constant. It is possible to stand up with respect to each of the surfaces of the single substrate 5. Therefore, since the micromesh 4a is moved by the external force to separate the paste material 3 into two together with the substrate 5a, the micromesh 4a needs to have a strength that does not deform during the movement. The same can be said for the micromesh 4b.
[0068]
As shown in FIG. 7, the CNT 2 that has come to stand is in a state of being bonded to both of the two substrates 5. Therefore, by cutting the CNT2 at the position indicated by the arrow in FIG. 7, the CNT2 is uniformly cut to a desired length as shown in FIG. Note that the cutting is not necessarily performed at two locations as shown in FIG. 7, but may be performed at one location.
[0069]
An energy beam can be used to cut the standing CNT2.
[0070]
As the energy beam, it is necessary to reliably cut the CNT 2 into a uniform length. Therefore, in order to meet such a demand, the energy density is 1 [mW / mm. ² ], More preferably 1 [W / mm ² It is possible to use the above laser beam. The upper limit of the energy density is appropriately set within a range where there is no possibility of burning or deteriorating the CNT2 near the position where the cutting is performed when the CNT2 is cut with a laser beam. It goes without saying that it is desirable.
[0071]
As energy beam, energy density is 1 [mW / mm ² ], More preferably 1 [W / mm ² It is also possible to use the above electron beam. Note that the upper limit of the energy density is the same as that of the laser beam.
[0072]
In addition, energy density is 1 [mW / mm as an energy beam. ² ], More preferably 1 [W / mm ² It is also possible to use the above ion beam. The upper limit of the energy density is the same as in the case of a laser beam.
[0073]
The CNT 2 may be cut by a mechanical cutting method instead of the energy beam. For example, cutter cutting using a thin diamond blade used for cutting a semiconductor wafer may be used.
[0074]
Thus, the electron-emitting device shown in FIG. 8 is completed. The micromesh 4 may be kept in the same position after the paste material 3 is divided into two substrates 5 as shown in FIG. 8, or the paste material divided into each substrate 5 (not shown). You may make it remove from 3.
[0075]
FIG. 9 shows the main part of the process for fabricating the cathode well of the FED. First, as shown in FIG. 9A, on the transparent electrode 6 made of ITO (Indium-Tin Oxide: indium and tin oxide film) formed on the surface of the glass substrate 5, for example, A resistance layer 7 made of silicon is formed, an insulating layer 8 made of SiO2 (silicon oxide film) is formed thereon, and a gate electrode layer 9 is further formed thereon. Then, as shown in FIG. 9B, vertical holes in the cathode well are drilled at predetermined positions by, for example, an etching method using a general photomask and photoresist 50 or the like. About the process so far, a general thing may be sufficient.
[0076]
Subsequently, as shown in FIGS. 10A and 10B, an emitter of SWCNT2 is formed. This process is the most important part of the manufacturing method according to the present embodiment.
[0077]
In order to make the formation position and shape of the emitter highly accurate, it is necessary to precisely control the distance and positional relationship between the relief plate 10 and the glass substrate 5. It is desirable to perform this process by placing the relief plate 10 and the glass substrate 5 on a table (not shown).
[0078]
First, the coating material 40 is transferred at a predetermined position on the substrate 5 by a transfer process such as a relief printing method. That is, first, a relief plate 10 corresponding to the shape of the emitter to be manufactured is prepared. Such a relief plate 10 can be manufactured using a photolithography (etching) method, an electron beam lithography method, a laser beam lithography method or the like generally used in a patterning process of a semiconductor device. Needless to say, they may be appropriately designed so as to meet various conditions required in accordance with the characteristics of the electron-emitting device and cathode well to be manufactured.
[0079]
Next, the coating material 40 is transferred as ink for each printing surface (part of the flat surface at the tip of the convex shape) of the prepared relief plate 10 (press plate), and the relief plate 10 is pressed against the glass substrate 5. 10A, the coating material 40 adhering to the printing surface of the relief plate 10 is exposed from the cathode well (vertical hole) on the glass substrate 5 in the plane (resistance layer). 7). In this case, it goes without saying that the relief plate 10 functions as one of the two substrates 5 in the manufacturing process described with reference to FIGS. However, in this case, the SWCNT 2 in an upright state is not necessarily formed on the printing surface of the relief plate 10, so the printing surface of the relief plate 10 exhibits wettability to the coating material 40 and has a resistance layer on the glass substrate 5 side. 7 may be set lower than the wettability of the surface.
[0080]
Subsequently, as shown in FIG. 10B, the relief plate 10 and the substrate 5 are separated from each other, so that each position where the coating material 40 is transferred is shown in FIG. 1, FIG. 2, and FIG. By the action described in the above description, the SWCNT 2 is raised, and for example, an emitter in which the support member 30 has a pointed protrusion shape can be manufactured.
[0081]
Here, by the method of separating the relief plate 10 and the substrate 5, it is possible to adjust the pointed protrusion shape of the emitter so as to have various desired shapes. First, when the relief plate 10 is slightly strongly pressed against the glass substrate 5 and then pulled away, the end portion is quickly separated from the relief plate 10 due to the effect of the viscosity of the paste material 3, and the center portion is later separated from the relief plate 10 so that the center is raised. Become. Therefore, if the movement speed of the relief plate 10 is adjusted as the end portions of the paste material 3 are sequentially separated from the relief plate 10, the amount of evaporation of the solvent of the paste material 3 is adjusted, and the form of the bulge in the center portion is adjusted. Can manage. Accordingly, the relief plate 10 and the glass substrate 5 are temporarily stopped or slowly separated from each other, and when the standby time has elapsed, the relief plate 10 is completely separated from the glass substrate 5. Is effective in forming various desired forms.
[0082]
11, 12, and 13 show an example in which electron-emitting devices are formed in an array on one substrate 5 by the manufacturing process shown in FIG. 10. In this way, the electron-emitting device using SWCNT2 can be manufactured uniformly over a large area.
[0083]
FIG. 14 shows an example of an FED using the electron-emitting device as shown in FIG. The FED includes an electron-emitting device 60 having one or a plurality of SWCNTs 2 standing on a substrate 5, a transparent electrode 6 for applying a predetermined voltage to the SWCNT 2 and emitting electrons e− from the SWCNT 2. A gate electrode 9 and a fluorescent part 70 (70R, 70G, 70B) that receives and emits electrons e− emitted from the electron-emitting device 60 are provided. The fluorescent part 70 is provided on a counter substrate 71 made of glass or the like so as to face each of the electron-emitting devices 60. Note that a large number of electron-emitting devices 60 are actually arranged in a matrix on the substrate 5 as shown in FIG.
[0084]
In this FED, when a voltage is selectively applied between the transparent electrode 6 and the gate electrode 9, field electron emission occurs in the electron-emitting device 60 located at the intersection, and electrons e− are emitted from the SWCNT2. Electrons e− emitted from the electron-emitting device 60 collide with the fluorescent part 70 and cause the phosphor to emit light. A desired image is displayed by the emission of the phosphor. Here, since the electron-emitting device 60 has the SWCNT 2 standing on the substrate 5, the electric field is effectively concentrated on the SWCNT 2, a high-brightness and clear image can be obtained, and the display quality is uniform over the entire screen. Will increase.
[0085]
As shown in FIG. 15, a protrusion 20 having a flat upper surface is formed on the surface of a substrate 5 such as a glass substrate, and the CNT 2 is provided upright on the flat upper surface of the protrusion 20. Good. By doing in this way, it becomes possible to concentrate an electric field more effectively on the front-end | tip part of CNT2 of the standing state in the whole shape of an electron emission element. Such a manufacturing method in which the protrusions 20 having a flat upper surface are provided on the surface of the substrate 5 and the CNTs 2 are provided in a standing state on the flat upper surface of the protrusions 20 is a tripolar field effect display device, This is particularly suitable for an FED in which an emitter is provided on the bottom surface of a so-called cathode well (vertical hole).
[0086]
As described above, since the electron-emitting device according to the present embodiment has the CNT 2 in an upright state on the substrate 5, it is possible to take advantage of the high aspect ratio, excellent electrical and mechanical characteristics of the CNT 2. Release characteristics can be improved.
[0087]
Further, if the support member 30 has a pointed protrusion shape, the electron emission performance can be further improved.
[0088]
Furthermore, in the manufacturing method of the electron-emitting device of the present embodiment, such an electron-emitting device can be realized by an extremely simple manufacturing method without facing various problems as in the case of the prior art. it can. Further, even if the support member 30 is a point-like protruding electron emission element, it can be formed very easily without requiring a complicated processing method and without facing various problems. .
[0089]
[Example]
An electron-emitting device using SWCNT2 was prepared by the manufacturing method as described above. As a result, as is apparent from the electron micrograph shown in FIG. 16, SWCNT 2 having a high aspect ratio (elongated and sharp) can be supported in an upright state from paste material 3. confirmed. Further, as is apparent from the electron micrograph shown in FIG. 17, it was confirmed that the SWCNTs 2 in an upright state can be distributed in a forested state with a uniform density.
[0090]
The present invention has been described with reference to the embodiments and examples. However, the present invention is not limited to the above embodiments and examples, and various modifications can be made. For example, the number of line-segmented CNTs 2 provided upright on the substrate 5 can be one, but a plurality of CNTs can also be used.
[0091]
Further, not only when the long CNT2 is used as shown in FIG. 6 and FIG. 7, but also when the length of the CNT2 is not uniform in FIG. 3 or FIG. It is possible to
[0092]
【The invention's effect】
As described above, according to the method for manufacturing an electron-emitting device of the present invention, the first substrate and the second substrate are provided with a coating material formed by mixing cylindrical carbon molecules and a material having a predetermined viscosity. After the two substrates are brought into close contact with each other, the two substrates are separated in a substantially vertical direction with respect to the respective substrate surfaces, so that cylindrical carbon molecules standing on the substrate can be formed with good shape reproducibility. . Therefore, a highly reliable and high-performance electron-emitting device and a display device can be easily realized.
[0093]
In particular, by forming the support member in a shape that protrudes sharply on the substrate, the electric field can be more effectively concentrated on the tip of the cylindrical carbon molecule, which is the portion of the emitter that substantially concentrates the electric field. Therefore, the performance as an electron-emitting device can be further enhanced.
[0094]
Further, if the substrate has a protrusion with a flat upper surface, and the cylindrical carbon molecule is provided on the flat upper surface of the protrusion in an upright state, the overall shape of the emitter is made of the cylindrical carbon molecule. The electric field can be more effectively concentrated on the tip portion, and the performance as the electron-emitting device can be further enhanced.
[0095]
Further, after the cylindrical carbon molecules are raised from the respective surfaces of the two substrates, the raised cylindrical carbon molecules are bonded to both of the two substrates, or deliberately. In the case where a long cylindrical carbon molecule is erected in advance and cut into a desired length, the erected cylindrical carbon molecule is cut between two substrates. The cylindrical carbon molecules in an upright state are cut to a uniform length, so that a cylindrical carbon molecular bundle having a uniform length, an electron-emitting device having a uniform performance, and a display device can be realized.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing a method for manufacturing an electron-emitting device according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view illustrating a process following FIG.
FIG. 3 is a cross-sectional view illustrating a process following FIG.
FIG. 4 is a cross-sectional view illustrating another manufacturing method according to an embodiment of the present invention.
FIG. 5 is a cross-sectional diagram illustrating a process following the process in FIG. 4.
FIG. 6 is a cross-sectional view illustrating still another manufacturing method according to an embodiment of the present invention.
7 is a cross-sectional diagram illustrating a process following the process in FIG. 6. FIG.
8 is a cross-sectional view illustrating a process following FIG.
FIG. 9 is a diagram illustrating a process of manufacturing a cathode well of an FED according to an embodiment of the present invention.
FIG. 10 is a cross-sectional view showing a process of manufacturing an emitter inside the cathode well of the FED following FIG. 9;
11 is a cross-sectional view showing an example in which electron-emitting devices are formed in an array on one substrate by the manufacturing process shown in FIG.
12 is a sectional view illustrating a process following the process in FIG. 11. FIG.
13 is a cross-sectional diagram illustrating a process following the process in FIG. 12. FIG.
FIG. 14 is a cross-sectional view illustrating an example of an FED according to the present embodiment.
FIG. 15 is a diagram illustrating an example of a case where a protrusion having a flat upper surface is formed on the surface of a substrate and the CNTs are provided upright on the flat upper surface.
FIG. 16 is an electron micrograph of one of the SWCNTs produced in the example.
FIG. 17 is an electron micrograph of SWCNT produced in an example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 (1a, 1b) ... Electrode, 2 ... CNT, 3 ... Paste material, 4 ... Micromesh, 5 (5a, 5b) ... Substrate, 7 ... Resistance layer, 9 ... Gate electrode, 10 ... Letterpress, 20 ... Protrusion

Claims (43)

An electron-emitting device comprising one or a plurality of cylindrical carbon molecules standing on a substrate. The electron-emitting device according to claim 1, wherein the cylindrical carbon molecule includes a single-walled carbon nanotube, a multi-walled carbon nanotube, or a carbon nanofiber. The electron-emitting device according to claim 1, wherein the cylindrical carbon molecule is supported in a standing state on the substrate by a support member made of a solidified material. The electron-emitting device according to claim 3, wherein the support member has a pointed protruding shape on the substrate. The electron-emitting device according to claim 3, wherein the support member has conductivity. 2. The electron-emitting device according to claim 1, wherein the length of the cylindrical carbon molecule is in the range of 10 [nm] to 100 [μm]. 2. The electron-emitting device according to claim 1, wherein the length of the cylindrical carbon molecule is in the range of 100 [nm] to 10 [μm]. 4. The electron-emitting device according to claim 3, wherein the support member is mixed with carbon fine particles. 9. The electron-emitting device according to claim 8, wherein the carbon fine particles have a size within a range of 1 [nm] to 1000 [μm]. 9. The electron-emitting device according to claim 8, wherein the carbon fine particles have a size in a range of 1 [nm] to 100 [μm]. The electron-emitting device according to claim 3, wherein the support member is mixed with metal fine particles. 12. The electron-emitting device according to claim 11, wherein the metal fine particles are made of one or more of IVa to Ib metals including Ti, Mo, W, Fe, Co, Ni, Cu, and Au. 12. The electron-emitting device according to claim 11, wherein the metal fine particles have a size within a range of 1 [nm] to 1000 [μm]. 12. The electron-emitting device according to claim 11, wherein the metal fine particles have a size in a range of 1 [nm] to 100 [μm]. The electron-emitting device according to claim 3, wherein the support member is formed to include a conductive polymer. The electron-emitting device according to claim 15, wherein the conductive polymer includes one or more of poly-P-phenylene vinylene (PPV), polyaniline, polythiophene, and polyacetylene. The electron-emitting device according to claim 3, wherein the support member is formed to include a conductive metal oxide. The electron-emitting device according to claim 17, wherein the conductive metal oxide includes one or more of tin oxide, titanium oxide, and indium oxide. 2. The electron-emitting device according to claim 1, wherein the substrate includes a protrusion having a flat upper surface, and the cylindrical carbon molecule is erected on the flat upper surface of the protrusion. 3. The electron-emitting device according to claim 1, wherein the substrate includes an electrode for applying a voltage to the cylindrical carbon molecule. An electron-emitting device having one or more cylindrical carbon molecules standing on a substrate;
An electrode for applying a predetermined voltage to the cylindrical carbon molecule to emit electrons from the cylindrical carbon molecule;
A display device comprising: a fluorescent portion that emits light upon receiving electrons emitted from the electron-emitting device. A mixing step in which a cylindrical carbon molecule and a material having a predetermined viscosity are mixed to produce a coating material;
An application step of applying the application material to at least one of the first substrate and the second substrate;
An adhesion step of bringing the first substrate and the second substrate into close contact with each other through a coating material;
And an element forming step of raising the cylindrical carbon molecule by separating the first substrate and the second substrate in a substantially vertical direction with respect to each substrate surface. Method. The method of manufacturing an electron-emitting device according to claim 22, wherein single-walled carbon nanotubes, multi-walled carbon nanotubes, or carbon nanofibers are used as the cylindrical carbon molecules. 23. The method of manufacturing an electron-emitting device according to claim 22, wherein the cylindrical carbon molecule is supported in a standing state on the substrate by a support member formed by solidifying the viscous material. 25. The method of manufacturing an electron-emitting device according to claim 24, wherein the support member is formed in a shape protruding in a peak shape on the substrate. 25. The method of manufacturing an electron-emitting device according to claim 24, wherein the support member is formed using a material having conductivity. 25. The method of manufacturing an electron-emitting device according to claim 24, wherein the support member is formed using a material mixed with metal fine particles. 28. The electron according to claim 27, wherein the metal fine particles are made of one or more of IVa to Ib metals including Ti, Mo, W, Fe, Co, Ni, Cu, and Au. A method for manufacturing an emitting device. 25. The method of manufacturing an electron-emitting device according to claim 24, wherein the support member is formed using a material containing a conductive polymer. 30. The method of manufacturing an electron-emitting device according to claim 29, wherein the conductive polymer includes one or more of poly-P-phenylene vinylene (PPV), polyaniline, polythiophene, and polyacetylene. The method of manufacturing an electron-emitting device according to claim 24, wherein the support member is formed using a material containing a conductive metal oxide. 32. The method of manufacturing an electron-emitting device according to claim 31, wherein the conductive metal oxide includes one or more of tin oxide, titanium oxide, and indium oxide. 23. The method of manufacturing an electron-emitting device according to claim 22, wherein a protrusion having a flat upper surface is formed on the surface of the substrate, and the cylindrical carbon molecule is provided upright on the flat upper surface of the protrusion. The method further includes the step of standing the cylindrical carbon molecules with respect to each of the surfaces of the two substrates, and then cutting the raised cylindrical carbon molecules between the two substrates. The method for manufacturing an electron-emitting device according to claim 22. 35. The method of manufacturing an electron-emitting device according to claim 34, wherein the raised cylindrical carbon molecules are cut by an energy beam. 36. The method of manufacturing an electron-emitting device according to claim 35, wherein a laser beam having an energy density of 1 [mW / mm ² ] or more is used as the energy beam. 36. The method of manufacturing an electron-emitting device according to claim 35, wherein a laser beam having an energy density of 1 [W / mm ² ] or more is used as the energy beam. 36. The method of manufacturing an electron-emitting device according to claim 35, wherein an electron beam having an energy density of 1 [mW / mm ² ] or more is used as the energy beam. 36. The method of manufacturing an electron-emitting device according to claim 35, wherein an electron beam having an energy density of 1 [W / mm ² ] or more is used as the energy beam. 36. The method of manufacturing an electron-emitting device according to claim 35, wherein an ion beam having an energy density of 1 [mW / mm ² ] or more is used as the energy beam. 36. The method of manufacturing an electron-emitting device according to claim 35, wherein an ion beam having an energy density of 1 [W / mm ² ] or more is used as the energy beam. 35. The method of manufacturing an electron-emitting device according to claim 34, wherein the raised cylindrical carbon molecules are cut by a mechanical cutting method. 23. The method of manufacturing an electron-emitting device according to claim 22, wherein a gate electrode corresponding to the raised cylindrical carbon molecule is formed on the surface of the substrate.

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