JP2006252781A - Electron gun and cathode-ray tube equipped with same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost electron gun with high electron emission density and low power consumption in a simple structure. <P>SOLUTION: The electron gun 16 comprises a field emission cathode 28, and an electronic lens system 30 for converging electrons emitted from the field emission cathode 28. The field emission cathode 28 is composed of a conductive wire 28a, and a carbon thin film 28c having a number of nano-size microporous protrusions 28b formed on the surface of the conductive wire 28a as electron emission sources. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electron gun of various electronic devices using a converged electron beam such as a CRT (cathode ray tube) or an electron beam exposure apparatus, and a CRT having the same.

  The CRT has a neck portion provided with an electron gun, a funnel portion provided with a deflection plate for deflecting an electron beam emitted from the neck portion, and a fluorescent screen portion on which a phosphor that emits and emits light by the electron beam is attached. And have. In such a CRT, an electron gun is used as an electron emission source. A conventional electron gun uses an indirectly heated cathode in which an oxide mainly composed of barium oxide is applied to the surface of a nickel cylinder with a built-in heater.

  However, in the case of an indirectly heated cathode, in addition to the problems such as it takes a long time to obtain an electron beam after the heater is turned on, and a long-life CRT cannot be obtained because the heater life is short, there is a demand for a recent CRT. However, there is a limit to improvement of current density in realizing high resolution, and there is a problem that it is difficult to realize a high-definition display or the like.

  Patent Document 1 has been proposed to solve the problems of the conventional electron gun using the indirectly heated cathode as described above. The electron gun disclosed in Patent Document 1 uses a field emission cathode. A cathode conductor is formed on a substrate, and an insulating layer having a large number of openings is provided on the cathode conductor. A Spindt-type emitter (electron emission source) is disposed in each opening of the layer, and a gate is disposed on the insulating layer. According to the description in the specification of Patent Document 1, it is stated that a field emission type cathode is a cold cathode, so that a heater power source is unnecessary, and current density (electron emission density) can be improved.

  However, since the emitter, which is an electron emission source, is a Spindt type, an expensive production facility for placing it in an ultra-high vacuum environment is necessary in the production process, and the structure of the electron emission source is complicated as described above. Therefore, there is a problem that the structure is unsuitable for mass production at a low cost because the number of manufacturing steps is very large and the manufacturing cost is high.

In the Spindt type, even if the emitter arrangement density is increased, there is another problem that it is difficult to secure the current density because the number of arranged emitters is limited in an electron gun having a small installation space.
JP-A-5-343000

  The problem to be solved by the present invention is to provide an electron gun that can greatly reduce mass production cost by reducing both equipment cost and manufacturing cost in an electron gun using a field emission cathode as an electron emission source.

  An electron gun according to the present invention includes a field emission cathode and an electron lens system that converges electrons emitted from the field emission cathode. The field emission cathode includes a conductive wire and a conductive wire. A carbon thin film having a large number of nano-sized fine protrusions is formed on the surface of the conductive wire as an electron emission source.

  It is preferable that the conductive wire has microscopic unevenness on the surface because more electrons can be emitted from the fine protrusions of the carbon thin film by applying a lower electric field. The carbon thin film includes, for example, a carbon thin film made of a nano-sized material having a tube shape, a wall shape, or other shapes.

  According to the electron gun of the present invention, it is possible to overcome the problems of the electron gun using the indirectly heated cathode, as well as the Spindt type electron emission source. In addition, since the number of manufacturing steps can be reduced, both the equipment cost and the manufacturing cost can be reduced, and the mass production cost can be greatly reduced.

  Furthermore, according to the electron gun of the present invention, a large number of fine protrusions are provided on the entire surface of the conductive wire, and a strong electric field concentration occurs on the fine protrusions when a low voltage is applied, so that electron emission can be performed. Even with a certain neck portion, a sufficiently high current density can be ensured only by arranging one or a plurality of wire-like cathodes.

  Further, since the emitter is discrete on the substrate in the Spindt type, it is necessary to increase the numerical aperture of the insulating layer in order to increase the electron emission density, but there is a limit to increase the current density by increasing the numerical aperture. On the other hand, in the present invention, since each of a large number of fine protrusions provided in the carbon thin film formed on the surface of the conductive wire can function as an emitter, a high current density can be ensured.

  According to the present invention, an electron gun using a field emission type cathode as an electron emission source can be provided with an inexpensive mass production cost.

  Hereinafter, an electron gun according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram illustrating a configuration of a CRT including an electron gun according to an embodiment. With reference to FIG. 1, this CRT 10 has an electron gun 16 housed in a neck portion 14 of a glass tube 12 whose inside is sealed to a high vacuum. A horizontal / vertical deflection plate 20 is disposed on the outer periphery of the joint portion between the neck portion 14 and the funnel portion 18 of the glass tube 12. A fluorescent screen portion 24 is provided on the inner surface of the panel 22 of the glass tube 12.

  The electron beam 26 emitted from the electron gun 16 is deflected by the horizontal / vertical deflection plate 20 and collides with the fluorescent screen unit 24, and the fluorescent screen unit 24 emits light by excitation. Note that the deflection method of the CRT 10 shown in FIG. 1 is an electrostatic deflection method, but the embodiment is not limited to this deflection method and can also be applied to an electromagnetic deflection method. The electromagnetic deflection method is a method in which the electron beam is deflected horizontally and vertically according to the strength and direction of the magnetic field of the magnet.

  The configuration of the electron gun 16 according to the embodiment will be described with reference to FIGS. FIG. 2 is a configuration diagram of the electron gun 16, and FIG. 3 is a detailed view of the field emission cathode 28. The electron gun 16 includes a field emission cathode 28 and an electron lens system 30.

  The field emission cathode 28 is characterized in that a conductive wire 28a and a carbon thin film 28c having a large number of nano-sized fine protrusions 28b on the surface as an electron emission source are formed on the surface of the conductive wire 28a. Is. The conductive wire 28a is preferably disposed so as to extend in a direction substantially perpendicular to the electron lens system 30.

  It is preferable that the conductive wire 28a has microscopic irregularities 28d formed on the surface because more electrons can be emitted from the fine protrusions 28b of the carbon thin film 28c by applying a lower electric field. The carbon thin film 28c includes, for example, carbon nanotubes, carbon nanowalls, fullerenes, carbon nanohorns, nanoparticles, and other carbon and carbon-based thin films. One or a plurality of conductive wires 28a may be used, or they may be combined in a mesh shape. The shape of the conductive wire 28a may be linear or serpentine. The cross section of the conductive wire 28a may be circular, elliptical, rectangular, or the like. The conductive wire 28a may have the same diameter in the length direction, but may have a part with a different diameter.

  The film thickness of the carbon thin film 28c is not particularly limited. It is preferable for the electric field concentration that the tip of the fine protrusion 28b is sharp, but it may be somewhat rounded. In the case of carbon nanowalls, the thinner the wall thickness, the better for electric field concentration. The method is not limited to a method of forming a carbon thin film such as a carbon nanotube or a carbon nanowall on the surface of the conductive wire 28a.

  There are various types of electron lens system 30, and the embodiment is not particularly limited to these lens systems. For the sake of explanation, the electron lens system 30 is composed of a plurality of grid electrodes. It consists of grid electrodes 30a-30e, and the electron beam 26 is accelerated and converged by applying a voltage to each of these grid electrodes 30a-30e. Each grid electrode 30a-30e has an opening through which the electron beam 26 passes.

  In the electron gun 16 of the embodiment described above, the problems of the electron gun using the indirectly heated cathode can be overcome, and the problems of the electron gun using the Spindt type field emission cathode are overcome. can do.

  That is, the field emission cathode 28 of the electron gun 16 of the embodiment has a strong electric field concentration by applying a low voltage to the sharp fine protrusions 28b provided on the surface of the carbon thin film 28c formed on the entire surface of the conductive wire 28a. It is possible to perform electron emission, and it is not necessary to manufacture in an ultra-high vacuum environment, and since the number of manufacturing steps can be reduced, both the equipment cost and the manufacturing cost can be reduced. In the case of mass production, the mass production cost can be greatly reduced as compared with the Spindt type field emission cathode.

  Furthermore, in the conventional Spindt-type field emission cathode, since the emitters are discretely arranged on the substrate, there is a limit in improving the current density. However, in the field emission cathode 28 of the electron gun 16 according to the embodiment, carbon Since each of the large number of fine protrusions 28b on the surface of the thin film 28c can function as an emitter, an electron gun having an extremely high current density can be realized.

  The present invention is not limited to the above-described embodiment, and includes various changes or modifications within the scope described in the claims.

It is a block diagram of CRT incorporating the electron gun which concerns on embodiment. It is a block diagram of the electron gun incorporated in CRT. It is a detailed block diagram of the field emission type cathode of an electron gun.

Explanation of symbols

10 CRT
DESCRIPTION OF SYMBOLS 12 Glass tube 14 Neck part 16 Electron gun 18 Funnel part 20 Horizontal / vertical deflection part 24 Fluorescent screen part 26 Electron beam 28 Field emission type cathode 28a Conductive wire 28b Fine protrusion 28c Carbon thin film 28d Concavity and convexity 30 Electron lens system

Claims (2)

  In an electron gun comprising a field emission cathode and an electron lens system for converging electrons emitted from the field emission cathode, the field emission cathode emits electrons onto the surface of the conductive wire and the conductive wire. An electron gun comprising a carbon thin film having a number of nano-sized fine protrusions on a surface as a source. A CRT comprising: a neck portion comprising the electron gun according to claim 1; a funnel portion for deflecting an electron beam emitted from the neck portion; and a fluorescent screen portion that emits and emits light by the electron beam.

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