ELECTRON-EMITTING DEVICE AND METHOD OF MANUFACTURING THE ELECTRON-EMITTING DEVICE

Abstract

An electron-emitting device includes a lower electrode, an emitter section formed from a dielectric material, and an upper electrode having fine through holes formed therein. When a drive voltage is applied between the lower electrode and the upper electrode, the electron-emitting device emits electrons from the emitter section through the fine through holes of the upper electrode. A protective film of oxide (e.g., silicon oxide) is formed on the upper surface of the emitter section. Thus, the upper surface of the emitter section is protected from attack of ionized gas molecules produced during electron-emitting operations. As a result, the upper surface of the emitter section becomes unlikely to be metalized, and thus, the amount of emitted electrons is unlikely to drop with the number of electron-emitting operations.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Various other objects, features and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description of the preferred embodiments when considered in connection with the accompanying drawings, in which:

FIG. 1 is a fragmentary, sectional view of an electron-emitting device according to a first embodiment of the present invention;

FIG. 2 is a fragmentary, sectional view of the electron-emitting device of FIG. 1;

FIG. 3 is a fragmentary plan view of the electron-emitting device of FIG. 1;

FIG. 4 is an enlarged fragmentary, sectional view of the electron-emitting device of FIG. 1;

FIG. 5 is an enlarged fragmentary, sectional view of the electron-emitting device of FIG. 1;

FIG. 6 is an enlarged fragmentary plan view of an upper electrode shown in FIG. 1;

FIG. 7 is a view showing another example of through holes of the upper electrode shown in FIG. 1;

FIG. 8 is a view showing a further example of through holes of the upper electrode shown in FIG. 1;

FIG. 9 is a view showing a still further example of through holes of the upper electrode shown in FIG. 1;

FIG. 10 is a view showing yet another example of through holes of the upper electrode shown in FIG. 1;

FIG. 11 is an enlarged fragmentary, sectional view of the upper electrodes and the emitter section shown in FIG. 1;

FIG. 12 is a view showing a state of the electron-emitting device shown in FIG. 1;

FIG. 13 is a graph of a voltage-polarization characteristic of the emitter section shown in FIG. 1;

FIG. 14 is a view showing another state of the electron-emitting device shown in FIG. 1;

FIG. 15 is a view showing a further state of the electron-emitting device shown in FIG. 1;

FIG. 16 is a view showing a still further state of the electron-emitting device shown in FIG. 1;

FIG. 17 is a view showing yet another state of the electron-emitting device shown in FIG. 1;

FIG. 18 is a view showing another state of the electron-emitting device shown in FIG. 1;

FIG. 19 is a view showing a state of emitted electrons in an electron-emitting device which does not have focusing electrodes;

FIG. 20 is a view showing a state of emitted electrons in the electron-emitting device shown in FIG. 1;

FIG. 21 is an enlarged fragmentary, sectional view of the upper electrodes and the emitter section of an electron-emitting device manufactured by an example manufacturing method of the present invention;

FIG. 22 is a view showing the process of formation of a protective film in the example manufacturing method of the present invention;

FIG. 23 is a view showing the process of formation of the protective film in the example manufacturing method of the present invention;

FIG. 24 is a graph showing the number of pulses vs. the amount of emitted electrons represented by relative value as tested on the electron-emitting device shown in FIG. 1 (an electron-emitting device which has the protective film) and on an electron-emitting device which does not have the protective film;

FIG. 25 is an electron micrograph of the surface (upper surface) of the emitter section of the electron-emitting device shown in FIG. 1;

FIG. 26 is a photograph showing detection of silicon (Si), by Auger electron spectroscopy, on the surface (upper surface) of the emitter section of the electron-emitting device shown in FIG. 25;

FIG. 27 is a photograph showing detection of lead (Pb), by Auger electron spectroscopy, on the surface (upper surface) of the emitter section of the electron-emitting device shown in FIG. 25;

FIG. 28 is a photograph showing detection of carbon (C), by Auger electron spectroscopy, on the surface (upper surface) of the emitter section of the electron-emitting device shown in FIG. 25;

FIG. 29 is an electron micrograph of the surface (upper surface) of the emitter section of an electron-emitting device whose durability is poor;

FIG. 30 is a photograph showing detection of silicon (Si), by Auger electron spectroscopy, on the surface (upper surface) of the emitter section of the electron-emitting device shown in FIG. 29;

FIG. 31 is a photograph showing detection of lead (Pb), by Auger electron spectroscopy, on the surface (upper surface) of the emitter section of the electron-emitting device shown in FIG. 29;

FIG. 32 is a photograph showing detection of carbon (C), by Auger electron spectroscopy, on the surface (upper surface) of the emitter section of the electron-emitting device shown in FIG. 29;

FIG. 33 is an enlarged fragmentary, sectional view of an electron-emitting device according to a second embodiment of the present invention; and

FIG. 34 is a fragmentary, sectional view of an electron-emitting device according to a modified embodiment of the present invention.

Claims

1. An electron-emitting device comprising: an emitter section formed from a dielectric material;a lower electrode formed on a lower portion of the emitter section; andan upper electrode formed on an upper portion of the emitter section in opposition to the lower electrode to sandwich the emitter section between the same and the lower electrode, and having a plurality of fine through holes formed therein, lower surfaces of portions of the upper electrode surrounding the fine through holes thereof being separated from and facing the emitter section,the electron-emitting device emitting electrons from the emitter section through the fine through holes of the upper electrode when a drive voltage is applied between the lower electrode and the upper electrode,wherein a protective film of oxide is formed on portions of an upper surface of the emitter section separated from the lower surface of the upper electrode and/or on portions of the upper surface of the emitter section exposed to the exterior of the upper electrode through the fine through holes of the upper electrode.

2. An electron-emitting device according to claim 1, wherein the protective film is formed in contact with both of the upper surface of the emitter section and the lower surface of the upper electrode at those portions of the upper surface of the emitter section where the upper surface of the emitter section starts to separate from the lower surface of the upper electrode, and is formed in contact with only the upper surface of the emitter section at those portions of the upper surface of the emitter section which are separated from the lower surface of the upper electrode.

3. An electron-emitting device according to claim 1, wherein the protective film is formed on the entire upper surface of the emitter section.

4. An electron-emitting device according to any one of claim 1, wherein the emitter section is formed from ceramic, and the protective film is of an oxide which contains atoms that are not replaced with atoms forming a crystallographic structure of the emitter section.

5. An electron-emitting device according to claim 4, wherein the atoms that are not replaced with the atoms forming the crystallographic structure of the emitter section are of silicon (Si).

6. An electron-emitting device according to claim 5, wherein the emitter section is formed from a compound including lead (Pb).

7. A method of manufacturing an electron-emitting device which comprises an emitter section formed from a dielectric material, a lower electrode formed on a lower portion of the emitter section, and an upper electrode formed on an upper portion of the emitter section in opposition to the lower electrode to sandwich the emitter section between the same and the lower electrode, and having a plurality of fine through holes formed therein, lower surfaces of portions of the upper electrode surrounding the fine through holes thereof being separated from and facing the emitter section, the electron-emitting device emitting electrons from the emitter section through the fine through holes of the upper electrode through application of a drive voltage between the lower electrode and the upper electrode, the method comprising the steps of: adding silicon or a compound containing silicon to a material used to form the emitter section, and firing the material for forming the emitter section; andforming a protective film of silicon oxide on the upper surface of the emitter section through application of heat to the emitter section in a reducing atmosphere.

8. A method of manufacturing an electron-emitting device according to claim 7, wherein the step of forming the protective film is practiced by applying heat to the emitter section in a state where a pasty and organometallic compound for forming the upper electrode is spread on the upper surface of the emitter section.