JP3189789B2 - Field emission cathode with planar focusing electrode - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field emission cathode with a flat focusing electrode used for a high definition field emission color display or the like.

[0002]

2. Description of the Related Art An electric field applied to a metal or semiconductor surface is 10
^At about ⁹ [volts / m], electrons pass through the barrier due to the tunnel effect, and electrons are emitted in a vacuum even at room temperature. This is called field emission (Field Emissin). A cathode that emits electrons based on this principle is called a field emission cathode (Field Emissin Cathode). By making full use of semiconductor microfabrication technology, it is possible to create a surface emission type field emission cathode consisting of micron-sized field emission cathodes, and a field emission display (Field Emissin Displa)
y), used as an electron emission source for an electron beam apparatus for lithography.

In a field emission display, a cathode substrate side and an anode substrate side are sealed with a predetermined gap therebetween, and the inside is kept in a vacuum state. When a Spindt-type cold cathode is used as the field emission cathode, when a positive gate voltage is applied to the extraction electrode, electrons are emitted from the emitter tip provided in the opening of the extraction electrode by field emission, and the positive voltage is reduced. The applied phosphor reaches the anode electrode, the phosphor covering the anode electrode emits light, and the display operation is performed. At this time, there is a field emission cathode with a plane focusing electrode in which a focusing electrode and a gate electrode are formed on the same plane of an insulating layer and an electron beam emitted from the field emission cathode is focused. By providing the focusing electrode, it is possible to reduce the rate at which the electron beam collides with the adjacent phosphor dots or the glass portion of the anode substrate, and to allow a margin in the positioning accuracy.

FIG. 6 is an explanatory view of a conventional field emission cathode with a flat focusing electrode. FIG. 6 (a) is a plan view of a field emission cathode with a flat focusing electrode, and FIG. 6 (b) is a corresponding anode. It is a top view on the side of a negative substrate. In the figure, 1 is a gate electrode, 1a is a gate wiring portion, 1b is a lead wire portion, 1c is a lead electrode portion, 2 is a focusing electrode, 3 is an insulating layer, 4 is an opening, 21
Is a phosphor (red), 22 is a phosphor (green), and 23 is a phosphor (blue).

[0005] As shown in FIG.
Are a gate wiring portion 1a, a lead line portion 1b, and a lead electrode portion 1c.
Consists of The gate electrode 1 and the focusing electrode 2 are formed on the same plane of the insulating layer 3. Extraction electrode part 1c
Is a vertically long rectangular shape, and three units arranged at equal intervals in the width direction (color selection direction) of the extraction electrode unit 1c constitute one unit,
It corresponds to each one of the three primary colors of one pixel. Each extraction electrode part 1c
An electron beam is emitted from the emitter tip in the plurality of openings 4. The focusing electrode 2 has a comb-tooth shape, and the extraction electrode portions 1c are arranged at intervals between the comb teeth. Each extraction electrode portion 1c has an open portion formed at an upper portion, and is surrounded by the focusing electrode 2 at equal intervals on the left, right, and lower sides.
The extraction electrode portion 1c is extracted through the opening of the focusing electrode 2 by the extraction line portion 1b, and is connected to the common gate wiring portion 1a. The width of the lead wire portion 1b is smaller than the width of the lead electrode portion 1c. The gate wiring portion 1a extends right and left, and a gate voltage is applied from the outside.

On the anode side shown in FIG.
There are three anode electrodes opposed to the three extraction electrode portions 1c. Each of the anode electrodes is covered with a rectangular three primary color phosphor (red) 21, a phosphor (green) 22, and a phosphor (blue) 23, and is arranged in stripes to constitute one pixel.
The electron beam emitted from each emitter tip collides with the corresponding phosphor (red) 21, phosphor (green) 22, and phosphor (blue) 23 while being focused by the focusing electrode 2. The phosphor emits light.

FIG. 7 is an explanatory view of the spot of the electron beam by the field emission cathode with the plane focusing electrode shown in FIG. The state of the light emitting surface on the anode substrate side is shown. In the figure, the same parts as those in FIG. 6 are denoted by the same reference numerals, and the description is omitted. Reference numerals 24, 25, and 26 are electron beam spots. As a result of evaluating the focusing characteristics of the electron beam in the above-described field emission cathode with a plane focusing electrode, the effect of the opening of the focusing electrode 2 was observed on the light emitting surface as the electron beam was focused. Since the extraction electrode section 1c cannot be completely surrounded by the focusing electrode 2, the electron beam emitted from the cone-shaped emitter leaks from the opening side of the focusing electrode 2, in the example of FIG. I can't get it.

In FIG. 7A, a phosphor (red) 21
Spot 24 of the electron beam reaching the phosphor, phosphor (green) 2
2. Electron beam spot 25 that reaches 2, phosphor (blue)
Each of the spots 26 of the electron beam arriving at is almost elliptical, but the shape is distorted due to insufficient focusing above. In FIG. 7B, the position of the spot of the electron beam is shifted above the phosphor.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a flat focusing electrode with reduced distortion of the shape of the electron beam spot on the light emitting surface and displacement of the arrival position. It is an object to provide a field emission cathode.

[0010]

According to the present invention, there is provided an insulating layer, an extraction electrode formed on the insulating layer, a plurality of openings formed in a laminated portion of the insulating layer and the extraction electrode, and a plurality of openings formed in the opening. A plane having an emitter chip provided thereon, and a focusing electrode formed on the insulating layer on the same plane as the extraction electrode, spaced around the extraction electrode and partially surrounding the extraction electrode with an open portion; In the field emission cathode with a focusing electrode, the extraction electrode is connected to the gate wiring through the opening by an extraction line, and the surface of the extraction line is covered with an insulating film. Therefore, the insulating film has an action of focusing the electron beam by an electric field formed by the electrons charged in the insulating film. As a result, the shape distortion of the electron beam spot, the displacement of the arrival position, and the like due to the effect of the opening of the focusing electrode on the light emitting surface when the electron beam is focused are reduced.

[0011]

FIG. 1 is a plan view for explaining a structure of a field emission cathode with a planar focusing electrode according to a first embodiment of the present invention. FIG. 2 is a partial cross-sectional view of the structure shown in FIG. 1 along the section line AA. In the figure, the same parts as those in FIG. 7 are denoted by the same reference numerals, and description thereof will be omitted. 5 is an insulating film, 11 is a cone-shaped emitter, 12 is a cathode substrate, 1
3 is a resistance layer. The field emission cathode with a planar focusing electrode according to this embodiment is provided in an opening 4 formed in a laminated portion of the extraction electrode portion 1c formed on the insulating layer 3, the insulating layer 3 and the extraction electrode portion 1c. An emitter chip such as a cone-shaped emitter 11 and the extraction electrode portion 1c are formed on the same plane of the insulating layer 3 together with the extraction electrode portion 1c, and are spaced around the extraction electrode portion 1c and partially surround the opening portion. It has a focusing electrode 2. The lead electrode 1c is connected to the gate wiring part 1a through the open part by the lead line part 1b,
The surface of the lead wire portion 1b is covered with the insulating film 5. The insulating film 5 may be formed of the same material as the insulating layer 3. Three extraction electrode portions 1c are provided in the width direction corresponding to each color of one pixel, and the focusing electrode 2 has four comb-tooth portions corresponding to one pixel so as to sandwich each extraction electrode 1c. Is provided.

Assuming that the potential of the focusing electrode 2 is 0 V, a voltage of about 80 V is applied to the gate electrode, so that the insulating film 5 covering the surface of the lead wire portion 1b of the gate electrode is charged with electrons.
The electric field formed by the electrons charged on the insulating film 5 has a function of focusing the electron beam. Therefore, the effect of the opening of the focusing electrode 2 is reduced.

As shown in FIG. 2, a resistance layer 13 is formed on a cathode substrate 12, and an insulating layer 3 is formed thereon. The cone-shaped emitter 11 is formed on the resistance layer 13 at the position of the opening 4 formed in the extraction electrode section 1c and the insulating layer 3. In the illustrated example, the extraction electrode portion 1c
1 shows a plurality of openings 4 arranged in one vertical line. However, the number of the arrangement of the openings 4 and the number of the openings 4 are not particularly limited.

Although not appearing in this cross section on the cathode substrate 12, for example, a cathode wiring portion is formed in a vertical direction on the cathode substrate 12 at the position of the comb teeth of the focusing electrode 2 in FIG. I have. The resistance layer 13 partially covers the cathode wiring portion, thereby forming the cone-shaped emitter 1.
The cathode current flows from 1 to the cathode wiring portion. By forming a matrix with the cathode wiring section and the gate wiring section 1a, a group of cone-shaped emitters 11 that emit electrons is selected. When pixels are selected by scanning the voltage applied to the focusing electrode 2, the focusing electrodes of adjacent pixels are formed separately, but when such selection is unnecessary, all the pixels are selected. The focusing electrode 2 of the pixel
It is formed to be one.

FIG. 3 is an explanatory view of the spot of the electron beam by the field emission cathode with the planar focusing electrode shown in FIGS. The state of the light emitting surface on the anode substrate side is shown. In the drawings, the same parts as those in FIGS. 6 and 7 are denoted by the same reference numerals, and description thereof will be omitted. The spot 24 of the electron beam reaching the phosphor (red) 21, the spot 25 of the electron beam reaching the phosphor (green) 22, and the spot 26 of the electron beam reaching the phosphor (blue) 23 are each Since the light is focused into an elliptical shape that matches the rectangular shape of the phosphor, distortion of the spot shape of the electron beam and displacement of the arrival position due to the open portion of the focusing electrode 2 are eliminated.

FIG. 4 is a plan view for explaining the structure of a field emission cathode with a planar focusing electrode according to a second embodiment of the present invention. FIG. 5 is a sectional view of the structure shown in FIG.
It is a fragmentary sectional view which follows A. In the drawings, the same parts as those in FIGS. 6 and 1 are denoted by the same reference numerals, and description thereof will be omitted. In this embodiment, the surfaces of the gate wiring portion 1a, the lead wire portion 1b, and the insulating layer 3 other than the extraction electrode portion 1c and the focusing electrode 2 of the gate electrode 1 are covered with the insulating film 5. As in the first embodiment, the electric field formed by the electrons charged on the insulating film 5 covering the surface of the lead wire portion 1b has a function of focusing the electron beam. The insulating film 5 may be formed of the same material as the insulating layer 3. Further, even when the distance between the gate electrode 1 and the focusing electrode 2 is small and the potential difference between the two is large, the edge of each electrode is covered and concealed.

[0017]

As is apparent from the above description, the present invention has the effect that the shape and position of the spot of the electron beam on the light emitting surface can be less affected by the open portion of the focusing electrode. If the lead wire portion, gate wiring portion, etc. are covered with an insulating film,
This has the effect of alleviating the problem of discharge.

[Brief description of the drawings]

FIG. 1 is a plan view for explaining a structure of a field emission cathode with a planar focusing electrode according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of the structure shown in FIG. 1, taken along section line AA.

FIG. 3 is an explanatory diagram of a spot of an electron beam by the field emission cathode with a planar focusing electrode shown in FIGS. 1 and 2;

FIG. 4 is a plan view for explaining a structure of a field emission cathode with a planar focusing electrode according to a second embodiment of the present invention.

5 is a partial cross-sectional view of the structure shown in FIG. 5, taken along section line AA.

6A and 6B are explanatory views of a conventional field emission cathode with a plane focusing electrode, FIG. 6A is a plan view of the field emission cathode with a plane focusing electrode, and FIG. 6B is a corresponding anode substrate; It is a top view of a side.

FIG. 7 is an explanatory diagram of an electron beam spot by the field emission cathode with a planar focusing electrode shown in FIG. 6;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Gate electrode, 1a Gate wiring part, 1b Leader part, 1c Leader electrode part, 2 focusing electrodes, 3 insulating layers, 4
Opening, 5 insulating film, 11 cone-shaped emitter, 12
Cathode substrate, 13 resistance layer, 21 phosphor (red), 2
2 phosphor (green), 23 phosphor (blue), 24, 25,
26 Electron Beam Spot

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01J 1/304

Claims (1)

(57) [Claims] 1. An insulating layer, an extraction electrode formed on the insulating layer, a plurality of openings formed in a laminated portion of the insulating layer and the extraction electrode, an emitter chip provided in the opening, and A planar focusing electrode-equipped field emission cathode which is formed on the insulating layer and on the same plane as the extraction electrode, and has a focusing electrode spaced around the extraction electrode and partially surrounding an opening. The field emission cathode with a planar focusing electrode, wherein the extraction electrode is connected to a gate wiring through the opening by an extraction line, and a surface of the extraction line is covered with an insulating film.