JPS63110537A - Electron source - Google Patents

Abstract

PURPOSE:To make it possible to control the length of a part, where electrons are emitted from a linear hot cathode, on the basis of the voltage applied to a planar electrode by equipping the planar electrode insulated from a rear electrode. CONSTITUTION:A voltage positive to a linear hot cathode 9 is applied to a lattice-shaped electrode 10, and a voltage negative to the linear hot cathode 9 is applied to a planar electrode 6, and the linear hot cathode 9 is heated at an enough temperature for electron emission. When a voltage negative to the linear hot cathode 9 is applied to rear electrodes 7 in this state, an electric field in the vicinity of the linear hot cathode 9 becomes negative and so electron beams 11 are not emitted. Next, when a positive voltage is applied to one of plural rear electrodes 7, an electric field capable of electron emission is formed on a part of the linear hot cathode 9's vicinity in correspondence with the part of positive voltage application, and so electron beams are emitted. At that time, the length of the part, where electrons are emitted from the linear hot cathode 9, can be made small due to effects given by the planar electrode 6 to the electric field.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electron source used in a flat display device for displaying characters, images, etc., and particularly relates to an electron source that generates a focused electron beam with a simple electrode configuration. .

2. Description of the Related Art An example of a conventional electron source will be described below with reference to the drawings.

FIGS. 3 and 4 show the main structure of a conventional electron source. In FIG. 3, a plurality of back electrodes 2 are formed on an insulating substrate 1, a plurality of linear hot cathodes 3 are arranged to intersect with the back electrodes 2, and a linear hot cathode 3 is arranged above the linear hot cathodes 3. A grid electrode 4 is arranged substantially parallel to the hot cathode 3.

The operation of the electron source configured as above will be explained below.

FIG. 4 is a cross-sectional view of the configuration of FIG. 2. In FIG. 4, a positive voltage is applied to the grid electrode 4 with respect to the linear hot cathode 2, the linear hot cathode 2 is heated to a temperature at which it can emit electrons, and a negative voltage is applied to the back electrode 2 with respect to the cathode. With voltage applied,
The vicinity of the linear hot cathode is in a negative electric field, and the electron beam 6 is not emitted. Next, when a positive voltage is applied to one of the multiple back electrodes, a part of the vicinity of the linear hot cathode corresponding to the part to which the positive voltage is applied becomes an electric field that can emit electrons from the cathode. , an electron beam is emitted.

Problems to be Solved by the Invention However, in the above configuration, the length of the part from which electrons are emitted from the cathode is mainly controlled by the potential of the back electrode. It is difficult to shorten the length of the electron beam, and therefore it is difficult to obtain a sufficiently small electron beam spot diameter, resulting in the problem that only high-resolution display can be obtained.

The present invention solves the above-mentioned problems of conventional sources and provides an electron source capable of improving electron beam focusing.

Means for Solving the Problems The electron source of the present invention has a plurality of linear hot cathodes and a lattice-like electrode arranged approximately parallel to the linear hot cathodes. A configuration in which a plurality of linear back electrodes that intersect with a linear hot cathode are arranged on the opposite side from the linear hot cathode, and a planar electrode that is airtightly insulated from the back electrode by an insulator. It is prepared.

Operation In the above structure of the present invention, an electron beam is emitted as in the conventional case, and by applying a negative voltage to the planar electrode with respect to the linear hot cathode, the length of the electron emitting portion of the cathode is reduced. The length can be easily shortened and a focused electron beam can be emitted.

Example Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing the main structure of an electron source in an embodiment of the present invention. 6 is a planar electrode, and the planar electrode 6 also serves as a substrate on which a back electrode 7 is arranged. The back electrode 7 is formed with an insulator 8 sandwiched between it and the planar electrode 6. Numeral 9 is a linear hot cathode, and a plurality of linear hot cathodes are stretched so as to be substantially orthogonal to the back electrode 7. The opening portion 10a of the grid-like electrode 1o for extracting the electron beam is arranged to face the back electrode 7.

The operation of the electron source configured as above will be explained using FIG. 2.

FIG. 2 is a cross-sectional view of the configuration of FIG. 1. In FIG. 2, a positive voltage with respect to the linear hot cathode 9 is applied to the grid electrode 10, a negative voltage with respect to the linear hot cathode 9 is applied to the planar electrode 6, and the linear hot cathode 9 is heated to a temperature that allows it to be released.

In the above state, when a negative voltage is applied to the back electrode 7 with respect to the linear hot cathode 9, a negative electric field exists in the vicinity of the linear hot cathode 9, and the electron beam 11 is not emitted. Next, when a positive voltage is applied to one of the plurality of back electrodes, a part of the vicinity of the linear hot cathode 9 forms an electric field capable of emitting electrons, corresponding to the part to which the positive voltage is applied. Yes, an electron beam is emitted. At this time, due to the influence of the planar electrode 6 on the electric field, the length of the portion from which electrons are emitted from the linear hot cathode 9 becomes shorter than when the conventional configuration is used.

Effects of the Invention As described above, the present invention provides a planar electrode that is electrically insulated from the back electrode, so that the length of the portion where electrons are emitted from the linear hot cathode can be applied to the planar electrode. It can be controlled by the voltage applied. Furthermore, by shortening the length of the portion from which electrons are emitted from the cathode, a focused electron beam can be extracted.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the configuration of main parts of an electron source in an embodiment of the present invention, FIG. 2 is a cross-sectional view of the structure shown in FIG. 1, and FIG. 3 is an example of the structure of main parts of a conventional electron source. FIG. 4 is a cross-sectional view of the configuration shown in FIG. 3. 1... Insulating substrate, 2, 7... River/back electrode, 3
, 9... Line hot cathode, 4, 10... Grid electrode, 5゜11... Electron beam, 6...
- Planar electrode, 8... Insulator. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure IO grid back electrode Figure 2 Figure 3 Figure 2 Back electrode

Claims (1)

[Claims] It has a plurality of linear hot cathodes and a lattice electrode arranged almost parallel to the linear hot cathode, and the linear hot cathode is arranged on the opposite side of the lattice electrode to the linear hot cathode. 1. An electron source comprising: a plurality of linear back electrodes intersecting a cathode; and a planar electrode electrically insulated from the back electrode by an insulator.