JP4895663B2 - Manufacturing method of field emission electron source - Google Patents

Description

  The present invention relates to a method for manufacturing a field emission electron source that emits electrons from a carbon film containing fibrous carbon such as carbon nanotubes or carbon nanofibers.

  Conventionally, carbon films containing fibrous carbon such as carbon nanotubes or carbon nanofibers have been used as field emission electron sources. In a field emission electron source, when an electric field is applied to a carbon film, electrons are emitted from the carbon film.

The carbon film is formed on the cathode electrode layer by a printing method. In order to improve the electron emission characteristics of the carbon film, an adhesive tape or the like is attached to the carbon film and then removed from the carbon film. By this treatment, the surface layer of the carbon film is removed. As a result, the tip of the fibrous carbon protrudes from the surface of the carbon film.
JP 2003-203559 A JP 2003-168355 A

  According to the conventional method, the degree of removal of the surface layer of the carbon film is not controlled. Therefore, due to variations in the distribution of the size and amount of fine particles such as glass serving as an adhesive contained in the carbon film in the plane direction, the exposed surface of the carbon film after the surface layer is removed is May have irregularities.

  In this case, due to the unevenness of the exposed surface of the carbon film, the distribution in the in-plane direction of the carbon film of the electric field applied to the exposed ends of the plurality of fibrous carbons occurs. For this reason, the amount of electrons emitted from the fibrous carbon varies depending on the position of the upper surface of the carbon film. As a result, when the field emission electron source is used in a display device, the uniformity of light emission in the in-plane direction of the display device varies.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a method for manufacturing a field emission electron source having uniform electron emission characteristics.

  The field emission electron source has a step of forming a laminated structure carbon having a plurality of carbon films containing fibrous carbon on the cathode electrode, and peeling at the interface between any two carbon films of the plurality of carbon films. And a step of peeling the pressure-sensitive adhesive tape after the pressure-sensitive adhesive tape is attached to the laminated structure carbon film.

  According to said manufacturing method, peeling arises in the interface of the carbon films which comprise laminated structure. Therefore, the flat upper surface of the carbon film is exposed. Fibrous carbon stands up from the flat upper surface. As a result, the uniformity of the distribution of electrons emitted from the field emission electron source is improved.

  In the method of manufacturing the field emission electron source according to the embodiment of the present invention, the formation of irregularities on the surface of the carbon film due to the peeling treatment is suppressed. For this purpose, first, a laminated structure carbon film in which a plurality of types of carbon films are laminated using a plurality of types of paste is formed. Thereafter, the carbon film located in the upper layer is removed so that peeling occurs at the interface between the carbon films constituting the laminated carbon film.

  In order to form the above-described laminated carbon film, a plurality of carbon films are laminated using a plurality of types of pastes having different weight mixing ratios of fine particles serving as adhesives such as glass fine particles. Thereby, it is possible to cause peeling at the time of peeling at a boundary of a specific laminated structure. As a result, the flatness of the upper surface of the carbon film after the peeling process is improved. Therefore, variation in the distribution of electron emission characteristics due to the unevenness of the upper surface of the carbon film is reduced. Therefore, the uniformity of electron emission from the carbon film is improved.

Hereinafter, field emission electron sources according to embodiments of the present invention will be described with reference to the drawings.
First, the problem of the method of manufacturing a field emission electron source that the inventors of the present application are trying to implement will be described with reference to FIGS.

  Generally, fibrous carbon such as carbon nanotubes and carbon nanofibers formed by a printing method such as screen printing or spray printing is used as the fibrous electron emission material of the field emission electron source. In the following, for convenience of explanation, a field emission electron source using carbon nanotubes will be described as an example as a representative of these fibrous carbons.

  Immediately after the carbon film is printed, the carbon nanotubes are tilted so as to extend along the surface of the carbon film due to the surface tension of the solvent component in the paste. In such a case, electric field concentration to the extent that electron emission is promoted does not occur at the tip portion of the carbon nanotube. Therefore, good electron emission characteristics cannot be obtained.

  Therefore, when the carbon film is formed by a printing method, a surface treatment for raising the carbon nanotubes from the surface of the carbon film is performed. Thereby, electric field concentration tends to occur at the tip of the carbon nanotube. As a result, good electron emission characteristics can be obtained.

  As the surface treatment as described above, there is a treatment (hereinafter referred to as “peeling treatment”) in which an adhesive pressure-sensitive adhesive tape is attached to the surface of the carbon film, and the pressure-sensitive adhesive tape is peeled off from the surface of the carbon film. . Note that the state in which the carbon nanotubes stand from the surface of the carbon film is called a raised state.

  FIG. 1 is a schematic view of a carbon film formed on a cathode electrode layer by a spray method or a screen printing method. In general, when a carbon film is used as the electron emission layer, the carbon film 111 is formed on the cathode electrode layer 102 on the glass substrate 101. The cathode electrode layer 102 is made of a metal such as ITO, Cr, or Al.

  At this time, it is necessary to increase the adhesion between the cathode electrode layer 102 and the carbon film 111 and the adhesion between the carbon nanotubes in the carbon film 111. For this purpose, the glass fine particles 103 are mixed together with the carbon nanotubes 104 in a printing paste for forming the carbon film 111. The glass fine particles 103 function as an adhesive. The paste may also contain an adhesive composed of fine particles such as silver or nickel together with the fine glass particles. If the carbon film 111 is baked at a temperature of 350 ° C. or higher, the fine particles serving as the adhesive are melted, and the above-described adhesion is ensured. In the following, for the convenience of explanation, a method for manufacturing a field emission electron source in which glass fine particles are used as fine particles serving as an adhesive will be described.

  In general, when the carbon film 111 is formed by a screen printing method, as described above, the carbon nanotubes 104, glass serving as an adhesive, and silver or nickel are used as solid components in the paste. Fine particles are mixed. In addition to the solid components described above, the paste contains a resin material such as ethyl cellulose or acrylic for printing these solid components on the cathode electrode layer 102. Further, the paste contains solvent components such as butyl carbitol (BC), butyl carbitol acetate (BCA), and terpineol for dissolving the above-described resin material. The paste also contains a dispersant for preventing the carbon nanotubes 111 and fine particles 103 such as glass from aggregating.

  If the above-described firing of the carbon film 111 is executed, not only the fine particles 103 such as glass or silver are melted, but also the components such as the resin, solvent, and dispersant in the paste are burned out.

  If the fine particles 103 such as glass, silver, or nickel are not mixed in the paste, it is possible to leave the carbon film 111 made of only the carbon nanotubes 104 after the carbon film 111 is baked. However, in this case, the adhesive force between the cathode electrode layer 102 and the carbon film 111 made of only the carbon nanotubes 104 is only van der Waals force, and is small. Moreover, the force with which the carbon nanotubes 104 are entangled is large. Therefore, when the peeling process is performed, the carbon film 111 is completely separated from the cathode electrode layer 102.

  FIG. 1 is a view showing a state after a carbon film 111 containing glass fine particles 103 as an adhesive material is baked on the cathode electrode layer 102. In FIG. 1, carbon nanotubes are used as fibrous carbon contained in the carbon film 111. FIG. 1 shows the state of the carbon film 111 before being peeled. As shown in FIG. 1, before the peeling process is performed, a carbon film 111 is formed on the cathode electrode layer 102 on the glass substrate 101, and the carbon film 111 plays a role as an adhesive. And the carbon nanotube 104.

  The state after the peeling process is performed on the carbon film 111 shown in FIG. 1 is shown in FIG. As shown in FIG. 2, when the peeling process is performed, carbon nanotubes 112 standing from the exposed surface of the carbon film 111 are formed.

  In the state before the peeling process shown in FIG. 1, the glass particles 103 are relatively uniformly mixed in the carbon nanotubes 104 in the portion 105. The film thickness of the carbon film 111 peeled off by the peeling process in the portion 105 is about one or two glass particles. Therefore, after the peeling process, the portion 105 in FIG. 1 becomes the portion 108 in FIG. The upper surface of the portion 108 is lower by about the size of one or two glass particles 103 than the upper surface of the carbon film 111 before the peeling process indicated by the line AA ′ in FIG. .

  On the other hand, in the portion 106 in FIG. 1, the density of the glass fine particles 103 is low in the vicinity of the cathode electrode layer 102 in a relatively wide range, and the glass fine particles 103 are not in contact with the cathode electrode layer 102. In this portion 106, the adhesion between the carbon film 111 and the cathode electrode layer 102 is small. Therefore, when the peeling process is performed, the carbon film 111 is completely peeled off from the portion 106. As a result, the cathode electrode layer 102 is exposed as in the portion 109 shown in FIG.

  Further, as shown in a portion 107 in FIG. 1, even in a portion 107 where the density of the glass fine particles 103 in the carbon film 111 is low in the central portion of the carbon film 111 in the thickness direction, the adhesive force is small. Therefore, when the peeling process is performed, as shown in FIG. 2, the upper surface of the portion 110 is formed at a position lower than the upper surface of the portion 108 formed by the desired peeling process.

  As described above, when the adhesion force between the cathode electrode layer 102 and the carbon film 111 is non-uniform or the adhesion force between the portions in the carbon film 111 is non-uniform, the carbon film 111 after the peeling process is formed. The unevenness of the surface becomes large.

  In the method for manufacturing the field emission electron source shown in FIG. 2, first, the cathode electrode layer 102 is formed on the glass substrate 101. Next, a carbon film 111 containing carbon nanotubes is formed on the cathode electrode layer 102 by a printing method. Thereafter, the carbon film 111 is fired and then peeled.

  In the field emission electron source formed by the above-described manufacturing method, as shown in FIG. 3, the electric field for extracting electrons from the carbon film 111 directly above the carbon film 111 is the cathode electrode layer 102 and the cathode electrode layer 102. Applied to the space between the anode electrode layer 114 and the anode electrode layer 114 facing each other.

  The anode electrode layer 114 is provided at a position facing the cathode electrode layer 102 to attract electrons emitted from the carbon film 111. The anode electrode layer 114 is made of a glass substrate on which a metal film such as ITO or Al is formed, or a metal plate such as Al or Mo. The anode electrode layer 114 is disposed at a distance d from the portion 108 of the carbon film 111 where the desired peeling process has been performed.

  When a field emission electron source having a bipolar structure as described above is installed in a vacuum chamber, the potential of the cathode electrode layer 102 is set to 0 V, and the potential of the anode electrode layer 114 is set to a positive value, carbon An electric field is applied to the space between the surface of the film 111 and the anode electrode layer 114. As a result, an electric field concentration occurs at the tip of the carbon nanotube 112 rising from the surface of the carbon film 111, and electrons are emitted. At this time, the amount of electrons emitted from the carbon nanotube 112 depends on the degree of electric field concentration on the surface of the carbon film 111. Therefore, the amount of electrons emitted from the tip of the carbon nanotube 112 increases as the electric field applied between the tip of the carbon nanotube 112 and the upper surface of the canode electrode layer 114 increases.

  The electric field applied between the carbon film 111 and the canode electrode layer 114 is the anode electrode layer 114 when the electric field applied to the space between the main surface of the carbon film 111 and the anode electrode layer 114 is constant. Depends on the distance between the main surface of the carbon film 111 and the main surface of the carbon film 111. That is, the longer the distance, the smaller the electric field.

  As shown in FIG. 3, in the portion 109, the carbon film 111 is peeled off to the bottom by a peeling process. Therefore, almost no carbon film 111 remains. On the other hand, in the part 110, the peeling process is performed to a position lower than the part 108 where the desired peeling process is performed. The portion 108 is subjected to a desired peeling process.

  Therefore, the distance between each of the portions 109 and 110 and the anode electrode layer 114 is larger than the distance between the portion 108 and the anode electrode layer 114. Therefore, the electric field applied to the space between each of the portions 109 and 110 and the anode electrode layer 102 is smaller than the electric field applied to the space between the portion 108 and the anode electrode layer 114. Accordingly, the amount of electron emission from the carbon nanotube 112 in each of the portions 110 and 109 is smaller than the amount of electron emission from the carbon nanotube 112 in the portion 108. In the portion 109, since the carbon nanotube 112 itself is small, the electron emission amount is the smallest.

  As described above, when unevenness occurs on the surface of the carbon film 111 due to the peeling process, the amount of electron emission varies on the surface of the carbon film 111 according to the unevenness. Therefore, electrons are not emitted uniformly from the surface of the carbon film 111. Therefore, in order to realize uniform electron emission from the carbon film 111, it is necessary to reduce the unevenness of the surface of the carbon film 111 after the peeling process.

  In order to suppress the occurrence of irregularities on the surface of the carbon film formed by the peeling process, it is necessary to peel the carbon film on the surface of the carbon film formed flat. Therefore, in the field emission electron source manufacturing method of the embodiment described below, the carbon film has a laminated structure formed of a plurality of types of pastes, and peeling is performed by peeling treatment at the interface of the laminated structure. generate.

  Hereinafter, the manufacturing method of the field emission type electron source according to the embodiment of the present invention will be described with reference to FIGS.

Embodiment 1 FIG.
First, the manufacturing method of the field emission power supply according to the embodiment of the present invention will be described with reference to FIG. In the method for manufacturing a field emission power supply according to the present embodiment, first, a cathode electrode layer 402 made of an ITO film is formed on a glass substrate 401. Next, a first carbon film 407 is formed on the cathode electrode layer 402 by using a screen printing method. Thereafter, for example, a drying process of the first carbon film 407 is performed at a temperature of 120 ° C. for 10 minutes. Next, a second carbon film 408 is formed on the first carbon film 407 using a screen printing method. Thereafter, for example, a drying process of the carbon film 407 and the second carbon film 408 is performed at a temperature of 120 ° C. for 10 minutes. A laminated structure carbon film 409 composed of the carbon film 407 and the carbon film 408 is formed by two drying processes as described above.

  Next, the firing process of the laminated structure carbon film 409 is performed for 1 hour in an atmosphere at a temperature higher than the temperature at which the glass fine particles 403 and 404 contained in the carbon film of the laminated structure carbon film 409 are softened, for example, 470 ° C. Executed. Thereby, the resin, the solvent, and the dispersant contained in the first carbon film 407 and the second carbon film 408 are removed. Further, the glass fine particles 403 and 404 contained in the carbon films 407 and 408 are softened.

In the present embodiment, the softening point of the glass is about 420 ° C., and the firing temperature may be any temperature as long as it is equal to or higher than this softening point temperature. However, when the heat resistance of the carbon nanotube is low, the carbon nanotube may be lost by firing. Therefore, it is desirable that the carbon films 407 and 408 be baked in an atmosphere free of oxygen, such as in an N ₂ or Ar atmosphere or a vacuum atmosphere. However, when the carbon films 407 and 408 are baked in these atmospheres, the resin and the dispersant contained in the paste are not completely removed. Therefore, the carbon films 407 and 408 are baked in the air at a temperature up to 400 ° C. where the resin and the dispersant are decomposed and disappeared, and in a N ₂ or Ar atmosphere or in a vacuum atmosphere at a temperature of 400 ° C. or higher. It is desirable that the carbon films 407 and 408 be fired.

  In the laminated structure carbon film 409 shown in FIG. 4, the bonding between the first carbon film 407 and the cathode electrode layer 402 is realized by the glass fine particles 403 included in the first carbon film 407. Further, the bonding between the first carbon film 407 and the second carbon film 408 is based on the adhesive force between the glass fine particles 403 in the first carbon film 407 and the glass fine particles 404 in the second carbon film 408, the first The adhesion between the glass fine particles 403 in the carbon film 407 and the carbon nanotubes 406 in the second carbon film 408, and the glass fine particles 404 in the first carbon film 407 and in the second carbon film 408. It is realized by the adhesive strength.

  Next, the adhesive tape which has an adhesive on the surface is affixed with respect to the above-mentioned laminated structure carbon film 409. FIG. Thereafter, a peeling process for peeling off the adhesive tape is performed.

  FIG. 5 is a schematic view showing a state where the adhesive tape 417 to which the adhesive 412 is attached is attached to the laminated structure carbon film 409. In the state shown in FIG. 5, the adhesive tape 417 attached to the laminated structure carbon film 409 is peeled off.

  At this time, the interface 413 between the cathode electrode layer 402 and the first carbon film 407, the interface 414 between the first carbon film 407 and the second carbon film 408, and the interface between the second carbon film 408 and the adhesive 412. 415, an interface 416 between the adhesive tape substrate 411 and the adhesive 412, a bonding surface between the glass fine particles 403 and the carbon nanotubes 405 in the first carbon film 407, and a glass fine particle 404 and carbon in the second carbon film 408. Peeling occurs at the position where the adhesion force is the smallest on the adhesion surface with the nanotube 406.

  That is, if the adhesion strength of the interface 414 between the first carbon film 407 and the second carbon film 408 in the above-mentioned interface or adhesion surface is the smallest, as shown in FIG. Arise.

  Therefore, if the interface 414 is flat, after the peeling process is performed, the occurrence of unevenness on the surface of the carbon film 111 as shown in FIG. 2 is suppressed. Therefore, the flatness of the upper surface of the carbon film 407 after the peeling process is ensured. That is, the carbon nanotube 405 rises from the flat upper surface of the carbon film 407. Therefore, the nonuniformity of the electric field due to the unevenness of the carbon film 407 is suppressed. Therefore, the electron emission characteristics of the carbon film 407 can be made uniform.

Next, a method for producing such a laminated carbon film will be specifically described.
First, a paste for forming the first carbon film 407 by screen printing is prepared.

  The paste contains carbon nanotubes, glass fine particles, ethyl cellulose (resin), a mixed solvent of butyl carbitol acetate and terpineol, and a dispersant.

The particle size of the glass fine particles mixed in the paste is determined from the following viewpoint.
After the peeling process is executed, the carbon nanotubes 405 stand up from the carbon film 407. Therefore, it is necessary that the unevenness on the surface of the carbon film 407 does not adversely affect the electron emission characteristics of the carbon film 407. Therefore, the arithmetic average surface roughness Ra indicating the unevenness of the surface of the first carbon film 407 after being fired is 1/10 of 3 μm in variation in height from the top surface of the carbon film 407 of the carbon nanotube 405. It is desirable that it is not more than .3 μm. Therefore, it is desirable that the average particle diameter of the glass fine particles 403 is in the range from 0.2 μm to 1.2 μm.

  Considering only the planarization of the upper surface of the carbon film 407, it is possible to use glass fine particles 403 having a particle size smaller than 0.2 μm. However, when glass fine particles 403 having an average particle size of 0.2 μm or less are used, the glass fine particles 403 are softened by firing, and then flow through the gaps between the carbon nanotubes 405 by capillary action, so that the first carbon Collect on the surface of the membrane 407. Therefore, the surface of the first carbon film 407 is covered with the glass fine particles 403. As a result, a glass layer is formed at the interface 414 between the first carbon film 407 and the second carbon film 408.

  Therefore, after the peeling process is performed, the raising process of the carbon nanotubes 405 is performed on the surface of the glass layer. The raised carbon nanotubes 405 and the cathode electrode layer 402 are electrically insulated by the glass layer. Therefore, electrons are not supplied from the cathode electrode layer 402 to the carbon nanotubes 405 raised. As a result, a problem that electron emission does not occur occurs. Therefore, the particle size of the glass fine particles 403 is desirably 0.2 μm or more as described above.

  The weight mixing ratio between the carbon nanotubes 405 and the glass fine particles 403 when forming the paste is determined from the following viewpoint.

  In the present embodiment, when the weight of the carbon nanotube 405 is 1, the weight of the glass fine particles 403 is 1 to 10. That is, the mixing weight ratio of the glass fine particles 403 to the carbon nanotubes 405 is in the range of 1-10.

  When the above-mentioned weight mixing ratio is smaller than 1, which is the lower limit, after the laminated structure carbon film 409 is formed, the adhesive force between the cathode electrode layer 402 and the first carbon film 407 and the first Adhesive strength between the glass fine particles 403 and the carbon nanotubes 405 in the carbon film 407 is not sufficiently ensured. Therefore, after the peeling process is performed, peeling partially occurs in the second carbon film 408 or at the interface 413 between the cathode electrode layer 402 and the first carbon film 407. Therefore, the weight mixing ratio of the glass fine particles 403 to the carbon nanotubes 405 needs to be 1 or more.

  When the weight mixing ratio is larger than 1, the adhesion between the cathode electrode layer 402 and the first carbon film 407 and the adhesion between the glass particles 403 in the first carbon film 407 and the carbon nanotubes 405. However, it increases as the weight mixing amount of the glass fine particles 403 with respect to the carbon nanotubes 405 increases. However, as the weight mixing amount of the glass fine particles 403 with respect to the carbon nanotubes 405 increases, the electrical resistance between the surface of the first carbon film 407 and the cathode electrode layer 402 varies depending on the position. Furthermore, a failure occurs in electrical contact between the cathode electrode layer 402 and the carbon nanotubes 405 in the first carbon film 407. As a result, the electron emission characteristics become non-uniform. Therefore, the weight mixing ratio of the glass fine particles 403 to the carbon nanotubes 405 is desirably 10 or less.

  Further, the flatness of the upper surface of the first carbon film 407 after being baked is important. The flatness of the upper surface of the first carbon film 407 is not only the particle size of the glass fine particles described above but also the weight mixing ratio of the carbon nanotube 405, the glass fine particles 403, the resin, the solvent, and the dispersant mixed in the paste. Also depends on.

  As described above, the weight mixing ratio of the glass fine particles 403 to the carbon nanotubes 405 is set to a value within the range of 1 to 10 when the weight of the carbon fine particles 403 is set to 1.

  The weight mixing ratio of the other resin, dispersant, and solvent is set so that the flatness Ra after firing of the first carbon film 407 is a value of 0.3 μm or less. The weight mixing ratio varies depending on the particle diameter of the glass fine particles 403 and the weight mixing ratio of the carbon nanotubes 405 and the glass fine particles 403. For example, the glass fine particles 403 having an average particle diameter of 0.3 μm On the other hand, when a paste mixed at a weight ratio of 5 is used, the carbon nanotube: glass fine particle: resin (ethylcellulose) + dispersant: solvent (butyl carbitol acetate) = 1: The relationship of 5:20:74 is established.

  The paste is prepared as described above, and is printed on the cathode electrode layer 402 made of ITO formed on the glass substrate 401 by a screen printing method, for example. Next, the paste is dried at 120 ° C. for 10 minutes. Thereby, the first carbon film 407 is formed. Thereafter, a second carbon film 408 is formed on the first carbon film 407. Similar to the first carbon film 407, the second carbon film 408 is printed by a screen printing method.

  As for the paste used for forming the second carbon film 408, adhesion at the interface 414 between the first carbon film 407 and the second carbon film 408 after the laminated structure carbon film 409 is baked. Made with power in mind.

  Specifically, the adhesive force at the interface 414 between the first carbon film 407 and the second carbon film 408 is the interface 413 between the cathode electrode layer 402 and the first carbon film 407, and the second carbon film 408. Adhesive force of the interface 415 between the surface of the substrate and the adhesive 412, the interface 416 between the adhesive tape substrate 411 and the adhesive 412, and the contact surface between the glass fine particles 403 and the carbon nanotubes 405 in the first carbon film 407. The weight mixing ratio of the material constituting the paste is determined so as to be smaller than each of the above.

  Therefore, the laminated structure carbon film 409 is generated at the interface 414 between the first carbon film 407 and the second carbon film 408 or inside the second carbon film 408 by peeling treatment. In order to realize this, the weight mixing ratio of the glass fine particles 404 in the paste for forming the second carbon film 408 to the carbon nanotubes 406 has a glass fine particle in the paste for forming the first carbon film 407. The weight mixing ratio of 403 to carbon nanotube 405 is smaller. That is, the distribution of the glass fine particles 403 is not constant in the film thickness direction of the laminated carbon film 409 after firing.

  More specifically, per unit volume in the order of the inside of the first carbon film 407, the interface 414 between the first carbon film 407 and the second carbon film 408, and the inside of the second carbon film 408. The amount of glass particles is low. The particle size of the glass fine particles 404 contained in the second carbon film 408 is not particularly limited. In the present embodiment, the second carbon film 408 containing glass fine particles 404 having the same particle diameter as the glass fine particles 404 contained in the paste used for the first carbon film 408 is used as an example. It is done.

  For example, as the paste used to form the first carbon film 407, the paste having a weight mixing ratio of the above-described carbon nanotube: glass: resin + dispersant: solvent = 1: 5: 20: 74 was used. In this case, as the paste for forming the second carbon film 408, a paste having a weight mixing ratio of carbon nanotube: glass: resin + dispersant: solvent = 4: 3: 9: 84 is used.

  The adhesive strength between the carbon nanotubes and the glass fine particles in the individual portions of the paste becomes smaller as the glass amount is smaller, and peeling occurs in the portion where the glass amount is small due to the peeling treatment. Therefore, in the configuration as described above, the adhesive force between the adhesive 412 of the adhesive tape 417 and the second carbon film 408 is greater than the adhesive force between the carbon nanotubes 406 and the glass particles 404 in the second carbon film 408. If it is larger, peeling of the laminated structure carbon film 409 occurs in the second carbon film 408 by peeling treatment. The state of the peeled surface at this time is basically the same as the state of the peeled surface after the single layer carbon film shown in FIG. 2 is peeled. That is, a flat peeling surface cannot be obtained.

  In this case, the peeling process is executed a plurality of times. Thereby, the flat upper surface of the first carbon film 407 is exposed. Therefore, the carbon nanotube 405 can be raised from the flat upper surface of the first carbon film 407.

  However, the selection range of the pressure-sensitive adhesive tape having such an adhesive force is narrow. Further, even when a pressure-sensitive adhesive tape having an adhesive force as described above is selected and peeled a plurality of times using it, the carbon nanotube 405 in the first carbon film 407 and the glass fine particles 403 There is a variation in the adhesive force between. For this reason, the first carbon film 407 is also peeled off together with the second carbon film 408. That is, it is difficult to expose the flat upper surface of the first carbon film 407 even if an adhesive tape having a desired adhesive force is used. Further, when the peeling treatment is performed a plurality of times, the residue of the pressure-sensitive adhesive on the surface of the carbon film causes a cause of deterioration of electron emission characteristics such as inhibition of raising of the carbon nanotube and contamination of the carbon nanotube.

  Therefore, in the present embodiment, the laminated structure carbon having such a structure that the peeling of the laminated structure carbon film 409 occurs at the interface 414 between the first carbon film 407 and the second carbon film 408 by one peeling process. A film 409 is formed. Therefore, the thickness after the second carbon film 408 is baked is equal to or less than the average thickness of the carbon film peeled off by one peeling process.

  FIG. 7 is a diagram showing a change in the average film thickness of the carbon film when peeling is performed a plurality of times on the baked carbon film. The average film thickness of the carbon film after the peeling process is calculated based on the average value of the film thickness of only the portion 108 that has been subjected to the predetermined peeling process shown in FIG. That is, the film thickness in the portion 109 where the carbon film has been completely removed to the extent that the cathode electrode layer 402 is exposed and the thickness in the portion 110 where the carbon film has been largely removed are calculated as the average value of the carbon film. Is excluded from the data for.

  From FIG. 7, when the average particle diameter of the glass particles 404 contained in the carbon film is 0.3 μm, the average thickness of the second carbon film 408 peeled by one peeling process is about It turns out that it is 0.5 micrometer. Further, from FIG. 7, when the average particle size of the glass fine particles 404 contained in the second carbon film 408 is 1.2 μm, the average second carbon film peeled off by one peeling process. It can be seen that the film thickness of 408 is 2 μm. In this measurement, the weight mixing ratio of the carbon nanotubes 406 and the glass fine particles 404 in the paste is 1: 0.75. Even when the weight mixing ratio is increased to 1:10, the same result as the above-mentioned effect is obtained.

  From this result, the thickness of the second carbon film 408 peeled by one peeling process depends on the particle diameter of the glass fine particles 404 in the second carbon film 408, and the ratio to the glass particle diameter is It is almost constant. Specifically, it is clear from the above results that the carbon film 408 having a thickness about 1.7 times the glass particle size 404 is peeled off by one peeling process.

  Therefore, in order to peel off the second carbon film 408 by one peeling process, the film thickness of the second carbon film 408 after baking is such that the glass fine particles 404 contained in the second carbon film 408 The average particle size is desirably 1.7 times or less.

  FIG. 8 shows that the weight mixing ratio of the carbon nanotubes 405 and the glass particles 403 in the first carbon film 407 is 1: 5, and the weight mixing ratio of the carbon nanotubes 405 and the glass particles 403 in the second carbon film 408 is as follows. The flatness of the film after the peeling treatment of the laminated structure carbon film 409 of 1: 0.75, the single-layer film made only of the first carbon film 407, and the single-layer film made only of the second carbon film 408 It is a figure which shows the result of having evaluated the change of this by arithmetic mean surface roughness Ra.

  The average particle diameter of the glass fine particles 403 mixed in the second carbon film 408 is 0.3 μm. In the laminated carbon film 409 after firing, the film thickness of the first carbon film 407 is 3 μm, and the film thickness of the second carbon film 408 is a film thickness that can be peeled off by one peeling process. .45 μm.

  In the present embodiment, in order to make the thickness of the baked second carbon film 408 0.45 μm, the above paste diluted with a solvent is used. In this embodiment, butyl carbitol is used as a solvent for diluting the paste. The film thickness of the single-layer film made only of the fired first carbon film 407 and the film thickness of the single-layer film made only of the fired second carbon film 408 are 3 μm, respectively.

  In any of the single-layer film made only of the first carbon film 407 and the single-layer film made only of the second carbon film 408, the surface roughness increases as the number of peelings increases. On the other hand, in the laminated structure carbon film 409, the surface roughness before peeling is larger than the surface roughness of the first carbon film 407 in terms of the surface roughness of the second carbon film 408. Therefore, the surface roughness of the laminated structure carbon film 409 is larger than the surface roughness of the single layer film consisting only of the first carbon film 407. However, the surface roughness after the first peeling of the laminated structure carbon film 409 is smaller than the surface roughness before peeling. That is, in the laminated structure carbon film 409, the flatness is improved by the peeling process, and the surface roughness matches the surface roughness of the first carbon film 407. Further, the film thickness of the first carbon film 407 after one peeling process is performed on the laminated structure carbon film 409 matches the film thickness of the first carbon film 407.

  From the above results, it can be seen that peeling at the interface 414 between the first carbon film 407 and the second carbon film 408 is realized by peeling the laminated structure carbon film 409 once. Further, when the laminated carbon film 409 is peeled twice or more, the surface roughness increases. This is because a peeling process is performed on the first carbon film 407 by the second and subsequent peeling processes. This is because the tendency of the increase in surface roughness after the second and subsequent peeling treatments of the laminated structure carbon film 409 is caused when the peeling treatment is performed on the single-layer film composed only of the first carbon film 407. It can also be seen from the fact that it is consistent with the trend of increasing surface roughness.

  FIG. 9 is a photomicrograph when the peeled state of the single layer carbon film and the laminated structure carbon film 409 is viewed from above. In the single-layer carbon film shown in FIG. 9A, it can be seen that there is a portion 701 where the ITO used as the cathode electrode layer is exposed by the peeling process. On the other hand, in the laminated structure carbon film shown in FIG. 9B, it can be seen that ITO is not exposed and the flatness is improved.

  In the present embodiment, the above-described laminated carbon film 409 is peeled to form a structure in which the carbon nanotubes 405 are erected from the first carbon film 407. This structure is used as an electron source. Therefore, the carbon nanotube 405 stands up from the flat upper surface of the first carbon film 407 in the electron source. Therefore, the distribution of electrons emitted from the electron source is made uniform.

  FIG. 10A is a view showing a light emission state of the phosphor resulting from the electron emission of the single-layer structure carbon film. FIG. 10B is a view showing a light emission state of the phosphor resulting from the electron emission of the laminated structure carbon film 409.

  Both the single-layer structure carbon film and the laminated structure carbon film 409 are peeled off using an adhesive tape composed of a Teflon (registered trademark) -based adhesive tape substrate and a Si-based adhesive and having an adhesive strength of 3.6 N. Has been implemented once. In addition, both the single-layer structure carbon film and the multilayer structure carbon film 409 emit electrons to the anode electrode in which a low-pressure phosphor (ZnO: Zn) is provided on a glass substrate with ITO.

  Each of the single layer structure carbon film and the laminated structure carbon film 409 has a planar shape of 2 mm × 2 mm, and the distance between the glass substrate on which the single layer structure carbon film is formed and the anode electrode, and The distance between the glass substrate on which the laminated carbon film 409 is formed and the anode electrode is about 60 μm. In addition, a current of 200 μA was passed through the cathode electrode, and the light emission state was observed.

  The electron source shown in FIG. 10A is provided with a single-layer structure carbon film, and has a dark region that does not emit light due to the unevenness of the film after peeling. On the other hand, the electron source shown in FIG. 10B is made up of only the first carbon film from which the second carbon film of the laminated structure carbon film is removed, and has a bright spot as compared with the single-layer carbon film. And a good light emission uniformity in the plane direction of the carbon film.

Embodiment 2.
Next, a field emission type electron source according to Embodiment 2 of the present invention will be described with reference to FIGS.

  FIG. 11 is a schematic diagram of the field emission electron source according to the present embodiment. In the field emission electron source of this embodiment, a cathode electrode layer 902 made of, for example, ITO or the like is formed on a glass substrate 901. On the cathode electrode layer 902, a first carbon film 908 including glass particles 903, a second carbon film 909 not including glass particles, and a third carbon film 910 including glass particles 904 are stacked. Each of the first carbon film 908, the second carbon film 909, and the third carbon film 910 is a mixture of carbon nanotubes 905, glass particles, resin, dispersant, and solvent at a predetermined weight mixing ratio. It is formed by printing paste. Note that the second carbon film 909 does not contain glass particles.

  The first carbon film 908 is formed, for example, through a drying process at 120 ° C. for 10 minutes after the paste is printed. Next, after the paste is printed, the second carbon film 909 is formed, for example, through a drying process at 120 ° C. for 10 minutes. Thereafter, after the paste is printed, the first carbon film 908 is formed, for example, through a drying process at 120 ° C. for 10 minutes.

  Further, the laminated structure carbon film 911 is baked in an air atmosphere at a temperature higher than the softening point of the glass fine particles 903 and 904 contained after the printing step, for example, a temperature of 470 ° C. Thereby, the solvent component, the resin component, and the dispersant component are removed from the first carbon film 908, the second carbon film 909, and the third carbon film 910. Further, the glass fine particles 903 and 904 in the first carbon film 908, the second carbon film 909, and the third carbon film 910 are softened. FIG. 11 is a cross-sectional view showing the structure of the laminated carbon film after this firing step.

  In the laminated structure carbon film 911, the first carbon film 908 and the cathode electrode layer 902 are bonded by the glass fine particles 903 included in the first carbon film 908. Further, the bonding at the interface 916 between the first carbon film 908 and the second carbon film 909 is performed by the glass fine particles 903 in the first carbon film 908, the carbon nanotubes 907 in the second carbon film 909, and This is done by the glass fine particles 904 in the third carbon film 910.

  Next, an adhesive tape 912 having an adhesive 914 is attached to such a laminated structure carbon film 911. Thereafter, a peeling process for peeling off the adhesive tape 912 is performed. FIG. 12 is a schematic diagram of a state in which an adhesive tape 912 to which an adhesive 914 has been attached is attached to the laminated structure carbon film 911.

  When the adhesive tape 912 attached to the laminated structure carbon film 911 shown in FIG. 12 is peeled off, peeling occurs on the surface having the smallest adhesive force among the following adhesive forces.

Adhesive force at interface 915 between cathode electrode layer 902 and first carbon film 908 Adhesive force at interface 916 between first carbon film 908 and second carbon film 909 Second carbon film 909 and third carbon film Adhesive force of interface 917 with 910 Adhesive force of interface 918 between third carbon film 910 and adhesive 914 Adhesive force of interface 919 between adhesive tape substrate 913 and adhesive 914 Glass in first carbon film 908 Adhesive force of the adhesion surface between the fine particles 903 and the carbon nanotubes 905 Adhesive force of the adhesion surface between the glass fine particles 904 and the carbon nanotubes 906 in the third carbon film 910 The second carbon film 909 includes glass fine particles 403. Therefore, the carbon nanotubes 905 are entangled with each other. For this reason, the carbon nanotubes 905 are in close contact with each other. As a result, peeling does not occur inside the second carbon film 909.

  Therefore, in the present embodiment, the adhesive force at the interface 917 between the second carbon film 909 and the third carbon film 910 is the smallest among the above-mentioned adhesive forces, or the first carbon film 908 and the first carbon film 908 are It is assumed that the adhesive force of the interface 916 with the second carbon film 909 is the smallest. Thereby, peeling always occurs at the interface 916 or the interface 917.

  Therefore, if the interface 917 is flat, the occurrence of unevenness on the upper surface of the second carbon film 909 after the peeling process as shown in FIG. 2 is suppressed. Therefore, the flatness of the upper surface of the second carbon film 907 is ensured even after the peeling process. As a result, the carbon nanotube 905 rises from the upper surface of the second carbon film 909. Therefore, the nonuniformity of the electric field due to the unevenness of the upper surface of the second carbon film 909 is suppressed. Therefore, the distribution of electrons emitted from the carbon film can be made uniform.

  On the other hand, when peeling occurs at the interface 916 between the first carbon film 908 and the second carbon film 909, the adhesive force at the interface 917 between the second carbon film 909 and the third carbon film 910 is increased. It is necessary to make it larger than the adhesive force at the interface 916 between the first carbon film 908 and the second carbon film 909.

  Therefore, the amount per unit volume of the glass fine particles 903 contained in the first carbon film 908 must be smaller than the amount per unit volume of the glass fine particles 904 contained in the third carbon film 910. However, in this case, the adhesive force at the interface 915 between the cathode electrode layer 902 and the first carbon film 908 is insufficient. Therefore, if the adhesive force of the adhesive 914 of the adhesive tape 912 used for the peeling process is not properly selected, peeling may occur at the interface 915 due to the peeling process.

  Therefore, in the three-layered laminated carbon film 911 as described above, the second carbon film 909 and the second carbon film 909 are formed rather than the separation at the interface 916 between the first carbon film 908 and the second carbon film 909. It is desirable to cause peeling at the interface 917 with the third carbon film 910. Therefore, it is desirable that the amount per unit volume of the glass fine particles 903 contained in the first carbon film 908 is larger than the amount per unit volume of the glass fine particles 904 contained in the third carbon film 910. According to this, the adhesive force at the interface 917 between the second carbon film 909 and the third carbon film 910 is greater than the adhesive force at the interface 916 between the first carbon film 908 and the second carbon film 909. And the separation occurs at the interface 917, and the separation does not occur at the interface 915 between the cathode electrode layer 902 and the first carbon film 908.

  Hereinafter, a method for producing a laminated carbon film having a three-layer structure as shown in FIG. 11 will be specifically described.

  First, a cathode electrode (for example, ITO, Al, Cr, or a laminated film thereof) 901 having a predetermined pattern is formed on a glass substrate 901. Next, a paste is applied on the cathode electrode layer 901 in a predetermined shape by a printing method. The paste includes carbon nanotubes, glass fine particles having an average particle size in the range of 0.3 μm to 1.2 μm, resin (ethyl cellulose or acrylic), and solvent (butyl carbitol, butyl carbitol acetate, terpineol, or a mixture thereof. ). Thereafter, the paste is dried at 120 ° C. for 10 minutes. Thereby, a first carbon film 908 is formed.

  The weight mixing ratio of the carbon nanotubes 905 and the glass fine particles 903 used in the paste for forming the first carbon film 908 is the same as the first carbon film 908 in the field emission electron source manufacturing method of the first embodiment. For the same reason as the weight mixing ratio in the paste for forming the glass, the weight of the glass fine particles 903 is set to 1 to 10 times the weight of the carbon nanotubes 905. The weight mixing ratio of the resin, the dispersant, and the solvent in the paste of the present embodiment is also the same as that of the first carbon film 908 of the first embodiment from the viewpoint of flatness required for the first carbon film 908. Similar weight mixing ratios are set.

  The weight mixing ratio of the substances in the paste used for forming the first carbon film 908 is CNT: glass: resin + dispersant: solvent = ethylcellulose as the resin and terpineol as the solvent. 1: 5: 20: 74.

  If the above-described paste is used, the flatness of the surface of the first carbon film 908 is 0.3 μm or less when expressed by Ra which is an index indicating the surface roughness. That is, the first carbon film 908 having a flat upper surface is formed. As the particle size of the glass fine particles mixed in the paste increases, the flatness of the first carbon film 908 deteriorates. Therefore, it is not preferable to use glass fine particles having a particle size of 1.2 μm or more. In addition, it is not preferable to use glass fine particles having a particle size of 0.3 μm or less for the same reason as described in the first embodiment.

  Next, a paste is applied in a predetermined shape on the first carbon film 908 by a printing method. This paste consists of carbon nanotubes and a resin (ethyl cellulose or acrylic) and a solvent (butyl carbitol, butyl carbitol acetate, terpineol, or a mixture thereof). Thereafter, the paste is dried at 120 ° C. for 10 minutes. Thereby, a second carbon film 909 is formed. For example, when the weight mixing ratio of each substance in the paste used to form the second carbon film 909 is ethyl cellulose as the resin and terpineol as the solvent, carbon nanotube: resin: solvent = 3: 4: 93. The flatness of the upper surface of the second carbon film 909 is such that the flatness of the carbon film obtained by printing the second carbon film 909 alone is 0.15 μm or less in terms of arithmetic average surface roughness Ra. Is set. Therefore, when the carbon nanotubes are pulverized and a paste is formed, the weight mixing ratio of the resin, the dispersant, and the solvent is set to a predetermined value.

  FIG. 14 is a view showing the arithmetic average surface roughness Ra of the surface of the laminated carbon film made of the two-layered carbon film from which the uppermost layer of the laminated carbon film made of the three-layered carbon film is removed. It is. The laminated structure carbon film shown in FIG. 13 is obtained by forming a second carbon film 909 that does not contain glass fine particles on a first carbon film 908 having a different arithmetic surface roughness Ra.

  From FIG. 14, the arithmetic surface roughness Ra of the second carbon film 909 formed on the first carbon film 908 tends to increase as the arithmetic surface roughness Ra of the first carbon film 908 increases. I understand that there is. It can also be seen that when the arithmetic surface roughness Ra of the first carbon film 908 is 0.3 μm or less, the surface roughness of the second carbon film 909 is also 0.3 μm or less. In addition, when the surface roughness Ra of the first carbon film 908 is 0.3 μm or more, the arithmetic surface roughness Ra of the second carbon film 909 is larger than the arithmetic surface roughness Ra of the first carbon film 908. It can be seen that this tends to be smaller. This result is a result obtained from a laminated carbon film in which the thickness of the fired second carbon film 909 is 1.5 μm. If the arithmetic surface roughness Ra of the second carbon film 909 is about 0.15 μm, the same result as described above is obtained regardless of the thickness of the second carbon film 909.

  Further, the relationship represented in the graph shown in FIG. 14 varies depending on the surface roughness of the second carbon film 909 alone. However, when the surface roughness of the second carbon film 909 alone is up to 0.3 μm, the graph shows the same tendency as the graph shown in FIG.

  As described above, the surface roughness of the upper surface of the second carbon film 909 reflects the flatness of the upper surface of the first carbon film 908 because glass fine particles are not included in the second carbon film 909. The Accordingly, by improving the flatness of the upper surface of the first carbon film 908, the flatness of the upper surface of the second carbon film 909 is improved. After such a second carbon film 909 is formed on the first carbon film 908 by a printing method, a drying process is performed at the aforementioned 120 ° C. for 10 minutes.

  Next, a third carbon film 910 is formed on the second carbon film 909 by a printing method. Similar to the first carbon film 908, the third carbon film includes glass fine particles 904. The particle size of the glass fine particles 904 included in the third carbon film 910 is not particularly limited. In the present embodiment, it is assumed that glass fine particles 904 having the same particle size as the glass fine particles 903 included in the first carbon film 908 are used.

  The weight mixing ratio of the carbon nanotubes 906, the glass fine particles 904, the resin, the dispersant, and the solvent contained in the paste used for forming the third carbon film 910 is determined as follows.

  The adhesive force at the interface 917 between the second carbon film 909 and the third carbon film 910 may be smaller than the adhesive force at the interface 916 between the first carbon film 908 and the second carbon film 909. is necessary. Therefore, the weight mixing ratio of the glass particles 904 to the carbon nanotubes 906 in the third carbon film 910 is smaller than the weight mixing ratio of the glass particles 903 to the carbon nanotubes 905 in the first carbon film 908. Further, it is assumed that the relationship of carbon nanotube: glass: resin + dispersant: solvent = 4: 3: 9: 84 is established. After the third carbon film 910 is printed on the second carbon film 909, a drying process is performed again at 120 ° C. for 10 minutes, and a laminated structure carbon film 911 having a three-layer structure is formed.

  Next, the laminated structure carbon film 911 having a three-layer structure is baked in the atmosphere at 470 ° C. for 1 hour, whereby the first carbon film 908, the second carbon film 909, and the third carbon film 910 are fired. The resin, solvent, and dispersant contained therein are removed. Further, the glass fine particles 903 and 904 contained in the first carbon film 908 and the third carbon film 910 are softened.

  The softening point of the glass particles used in the present embodiment is about 420 ° C. The firing temperature of the glass fine particles may be a temperature equal to or higher than the softening point of the glass fine particles.

In addition, when the heat resistance of a carbon nanotube is low, a carbon nanotube may lose | disappear in a baking process. Therefore, it is desirable that the firing process be performed in an N ₂ atmosphere, an Ar atmosphere, or a vacuum atmosphere. However, when the firing step is performed in an N ₂ atmosphere, an Ar atmosphere, or a vacuum atmosphere, the resin and the dispersant contained in the paste are not completely removed. Therefore, firing is performed in the atmosphere up to 400 ° C. at which the resin and the dispersant decompose and disappear, and the firing step is performed in an N ₂ atmosphere, Ar atmosphere, or vacuum atmosphere at a temperature of 400 ° C. or higher. It is desirable.

  A peeling treatment is performed on the laminated carbon film 911 having a three-layer structure that has undergone the firing process as described above. This peeling process will be described with reference to FIG.

  As shown in FIG. 11, a cathode electrode layer 902 is formed on a glass substrate 901. Next, on the cathode electrode layer 902, a first carbon film 908 including glass particles 903, a second carbon film 909 not including glass particles, and a third carbon film 910 including glass particles 904 are arranged in this order. Thus, a laminated structure carbon film 911 is formed.

  The weight mixing ratio of the glass fine particles 903 to the carbon nanotubes 905 in the first carbon film 908 is larger than the weight mixing ratio of the glass fine particles 904 in the third carbon film 910. That is, the amount of glass fine particles 903 contained per unit volume in the first carbon film 908 is larger than the amount of glass fine particles 904 contained per unit volume in the third carbon film 910. That is, the weight of the glass particles 903 bonded to the carbon nanotubes 907 in the second carbon film 908 is larger than the weight of the glass particles 904 bonded to the carbon nanotubes 907 in the third carbon film 910. Therefore, the adhesive force at the interface 916 between the first carbon film 908 and the second carbon film 909 is larger than the adhesive force at the interface 917 between the second carbon film 909 and the third carbon film 910.

  Therefore, when the peeling treatment is performed on the above-described laminated carbon film 911 having the three carbon films, peeling occurs at the interface 917 between the second carbon film 909 and the third carbon film 910 having the smallest adhesion. Arise. Thereby, as shown in FIG. 12, a structure in which the carbon nanotubes 907 are erected from the flat upper surface of the second carbon film 909 is formed.

  However, similarly to the method of manufacturing the field emission electron source described in Embodiment 1, the thickness of the third carbon film 910 is 1.7 of the glass fine particles 904 included in the third carbon film 910. If it is larger than twice, a part of the third carbon film 910 may remain on the second carbon film 909 in one peeling process.

  In such a case, the carbon nanotube 907 is formed with a structure rising from the upper surface of the first carbon film 908 having projections and depressions. According to this structure, there is a large variation in electron emission characteristics as compared with a structure that rises from the flat upper surface of the second carbon film 909. Therefore, peeling of the third carbon film 910 may be performed so that the peeling process is performed a plurality of times and the flat upper surface of the second carbon film 909 is exposed. However, according to this, the adhesive 914 of the adhesive tape 912 remains on the upper surface of the second carbon film 909 for the same reason as described in the first embodiment. In this case, there is a risk of deteriorating electron emission characteristics and increasing variations.

  Therefore, also in this embodiment, for the same reason as described in Embodiment 1, the film thickness of the third carbon film 910 is a film thickness that is peeled by one peeling process, that is, glass. The thickness is preferably 1.7 times or less the average particle diameter of the fine particles 904.

  Therefore, as in the case of the first embodiment, the third carbon film 910 including glass fine particles 904 having an average particle diameter of 0.3 μm may have a thickness of 0.45 μm after the firing process is performed. desirable. Therefore, as a paste used for forming the third carbon film 910, a paste having a mixing ratio of the above-described carbon nanotube: glass: resin + dispersant: solvent = 4: 3: 9: 84 is butyl. Those diluted with carbitol acetate are used. A third carbon film 910 is formed by this paste, and a laminated carbon film 911 having a three-layer structure is formed.

  After each layer of the laminated structure carbon film 911 is fired, the film thickness of the first carbon film 908 is 2 μm, the film thickness of the second carbon film 909 is 1 μm, and the film of the third carbon film The thickness is 0.45 μm. FIG. 15 shows the surface of the carbon film after the laminated structure carbon film 911 is peeled. From FIG. 15, the upper surface of the laminated structure carbon film 911 is not exposed to the cathode electrode layer 102 locally, like the surface of the two-layer structure carbon film shown in FIG. It can be seen that the peeling process is performed uniformly.

  FIG. 16 is a photograph when the cross section of the three-layer structure carbon film is observed by SEM (Scanning Electronic Microscope) before and after the peeling treatment. FIG. 16A shows a state before the peeling process, and FIG. 16B shows a state after the peeling process.

  When comparing FIG. 16A and FIG. 16B, the third carbon film 910 is removed by the peeling process, and from the interface 917 between the second carbon film 909 and the third carbon film 908, that is, From the upper surface of the second carbon film 909, it can be seen that the carbon nanotubes 907 are raised and the flatness of the upper surface of the second carbon film 909 is good. Therefore, the distribution of electrons emitted from the plurality of carbon nanotubes 907 in the pixel can be made uniform.

  Next, referring to FIG. 17, the emission state of an electron source having a single-layer carbon film is compared with the emission state of an electron source having a two-layer carbon film from which the uppermost layer of the three-layer structure is removed. The

  FIG. 17A shows an electron emitted from a carbon film having a single-layer structure as an electron source colliding with an anode phosphor in which a glass substrate with ITO is attached with a low-pressure phosphor (ZnO: Zn). It is a photograph which shows the light emission state at the time of doing. For the single-layer carbon film, a peeling treatment is performed once using an adhesive tape having an adhesive force 306N made of a Teflon (registered trademark) adhesive tape substrate and an Si adhesive, The top is removed.

  In FIG. 17B, electrons emitted from a carbon film having a two-layer structure as an electron source collide with an anode phosphor in which a low-pressure phosphor (ZnO: Zn) is attached to a glass substrate with ITO. It is a photograph which shows the light emission state at the time of doing. The laminated structure carbon film having a two-layer structure has an adhesive force 306N made of a Teflon (registered trademark) adhesive tape substrate and a Si-based adhesive with respect to the laminated structure carbon film having a three-layer carbon film. Using an adhesive tape, the peeling process was performed once and the uppermost carbon film was removed.

  In any of the structures shown in FIGS. 17A and 17B, the size of the carbon film is 2 mm square, and the distance between the glass substrate on which the carbon film is formed and the anode electrode layer is about 60 μm. The observation of the light emission state is performed in a state where a current of 200 μA flows through the cathode electrode layer 102.

  As shown in FIG. 17 (a), the electron source using the single-layer carbon film from which the upper portion has been removed has a region that does not emit light uniformly due to the unevenness of the carbon film after the peeling treatment. is doing. On the other hand, as shown in FIG. 17B, the laminated structure carbon film having the two-layer structure from which the uppermost layer is removed is excellent in the flatness of the carbon film after the peeling treatment, In comparison, it has a large number of bright spots and good emission uniformity.

  Note that in the case where peeling occurs at the interface 916, the carbon nanotube 905 rises from the upper surface of the first carbon film 908 as shown in FIG. That is, the uppermost layer and the intermediate layer carbon films 909 and 910 of the three-layer structure carbon film are removed, and the upper surface of the carbon film 908 is flat. Also by this, the same effect as that obtained by the laminated structure carbon film in which peeling occurs at the interface 917 can be obtained.

  In each of the above embodiments, carbon nanotubes are used as the field emission electron source. However, if the electron emission source utilizes the field effect, for example, other fibrous carbons such as carbon fiber and carbon nanowire are used. May be used.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a figure for demonstrating the single layer carbon film of a comparative example. It is sectional drawing explaining the carbon film after the peeling process of a comparative example. It is sectional drawing which shows a state when evaluating the electron emission characteristic of the single layer carbon film of a comparative example. FIG. 3 is a cross-sectional view for explaining the laminated structure carbon film of the first embodiment. It is sectional drawing for demonstrating the state by which the adhesive tape was affixed with respect to the laminated structure carbon film of Embodiment 1. FIG. FIG. 3 is a cross-sectional view for explaining a state where the adhesive tape is peeled off from the laminated structure carbon film of the first embodiment. 4 is a graph showing the relationship between the number of peeling processes described in Embodiment 1 and the film thickness of a carbon film. It is a figure which shows the relationship between the frequency | count of each peeling process of the single layer carbon film demonstrated in Embodiment 1, and the surface roughness of the carbon film after a peeling process. 4 is a photograph of a microscopic observation result of the surface after peeling of the single-layer carbon film and the laminated structure carbon film described in the first embodiment. 4 is a photograph showing a phosphor emission state by electrons emitted from an electron source in which the single-layer carbon film and the laminated carbon film described in Embodiment 1 are peeled. 6 is a cross-sectional view illustrating a laminated structure carbon film according to a second embodiment. FIG. It is sectional drawing for demonstrating the state which the adhesive tape affixed with respect to the laminated structure carbon film of Embodiment 2. FIG. It is sectional drawing for demonstrating the state by which the adhesive tape was peeled off from the laminated structure carbon film of Embodiment 2. FIG. It is a figure which shows the relationship between the surface roughness of the 1st carbon film demonstrated in Embodiment 2, and the surface roughness of the laminated structure carbon film in which the 2nd carbon film was formed on the 1st carbon film. It is a photograph of the microscope observation result of the surface after peeling of the laminated structure carbon film of Embodiment 2. 4 is an electron micrograph of a cross section of each carbon film before and after peeling treatment of a laminated structure carbon film shown in Embodiment 2. FIG. FIG. 5 is a photograph showing the light emission state of the phosphor when each of the single-layer carbon film and the laminated structure carbon film described in Embodiment 2 is used as an electron source after being peeled.

Explanation of symbols

  101 glass substrate, 102 cathode electrode layer, 103 glass fine particles, 104 carbon nanotube, 105, 106, 107, 108, 109, 110 part, 111 carbon film, 112 carbon nanotube, 114 anode electrode layer, 203 carbon film, 205 part, 401 glass substrate, 402 cathode electrode layer, 403 glass particulate, 404 glass particulate, 405,406 carbon nanotube, 407,408 carbon film, 409 laminated carbon film, 411 adhesive tape substrate, 412 adhesive, 413, 414, 415 , 416 interface, 417 adhesive tape, 701 part, 901 glass substrate, 902 cathode electrode layer, 903, 904 fine glass particles, 905, 906, 907 carbon nanotube, 908, 90 9,910 Carbon film, 911 Laminated structure carbon film, 912 Adhesive tape, 913 Adhesive tape base material, 914 Adhesive, 915,916,917,918,919 Interface.

Claims (9)

Forming a laminated carbon film having a plurality of carbon films containing fibrous carbon on the cathode electrode;
An electric field comprising a step of attaching an adhesive tape to the laminated structure carbon film and then peeling the adhesive tape so that peeling occurs at the interface between any two carbon films of the plurality of carbon films. A method of manufacturing an emission electron source. The laminated structure carbon film is composed of a first carbon film formed on the cathode electrode, and the second carbon film formed on said first carbon film,
The first carbon film and the second carbon film are formed by firing the first paste and the second paste, respectively.
The first paste includes first fibrous carbon and first fine particles,
The second paste includes second fibrous carbon and second fine particles,
The mixing ratio by weight of the second fine particles to the second fibrous carbon is less than the weight mixing ratio of said first fine particles for said first fibrous carbon, field emission type according to claim 1 Manufacturing method of electron source.   The method of manufacturing a field emission electron source according to claim 2, wherein a weight mixing ratio of the first fine particles to the first fibrous carbon is within a range of 1 to 10. 3. The method of manufacturing a field emission electron source according to claim 2, wherein a thickness of the second carbon film is not more than 1.7 times an average particle diameter of the second fine particles.   3. The method of manufacturing a field emission electron source according to claim 2, wherein the peeling step is executed only once. The laminated structure carbon film, wherein the first carbon film formed on the cathode electrode, and the second carbon film formed on said first carbon film is formed on the second carbon film It was and a third of the carbon film,
It said first carbon film, said second carbon film, and the third carbon film, respectively, a first paste, is formed by firing of the second paste, and the third paste,
The first paste includes first fibrous carbon and one fine particle,
The second paste contains the second fibrous carbon without containing fine particles ,
The third paste, and a third fibrous carbon and other side of the fine particles,
2. The method of manufacturing a field emission electron source according to claim 1, wherein in the peeling step, peeling occurs at an interface between the third carbon film and the second carbon film. Mixing ratio by weight of the other side of fine particles to said third fibrous carbon is less than the weight mixture ratio of the one fine particles against the first fibrous carbon emissions, the field emission of claim 6 Type electron source manufacturing method. The thickness of the third carbon film, the 1.7 times or less of the average particle diameter of the other side of the fine particles, a method of manufacturing a field emission electron source of claim 6.   The method of manufacturing a field emission electron source according to claim 6, wherein the peeling step is executed only once.