FIELD OF THE INVENTION

This invention relates to electron-emission devices and to vacuum microelectronics, more particularly to intergral modules, including various internal systems of electron-emission devices as applied to field-emission, thermal-emission, and photo-emission cathodes, including those with diamond coatings, as well as to devices based on field emission, thermal emission, and photoemission, such as displays, microwave devices, memories, etc.

PRIOR ART

All known electron-emission devices for flat panels (in particular, displays) can be divided in two classes. One of them can be designated by the formula "one-one", where against a cathode is only one point ("pixel") of an anode, as an output device reproducing a point (spot) that is perceived by an external observer ("signal consumer") and carries a certain information on its only coordinate and/or feature (for example, colour). Another class can be designated as "one-plurality", where against the cathode are two or more points of the anode, as an output device reproducing points (spots) that are perceived by an external observer as different coordinates and carry a certain information on each own coordinate and/or feature (for example, colour).

From this point of view, the emission device [1], based on deflection of an electron beam, should be considered as belonging to the devices of the first class, because, for an external observer, the deflection of the beam in the scopes of the same beam does not change the coordinates of the luminous spot, while just changes its feature (the colour of the spot), that it was intended in [1]. In the device [2], the beam deflection leads, for an external observer, to a shifting of the luminous spot (to a change of its coordinates); such a device can be ranked to the second class. If one,s accept such a conditional classification, the given invention should be ranked to the second class of the flat-panel emission devices.

There are known flat-panel emission devices [2], where the electron beam, leaving from the cathode, is deflected. However, there is no gate electrode that could allow for special drivers to work at low (10-30 V) voltages and, by modulation of the beam, reproduce the information signal. In addition, there are no electrostatic focusing lenses, that could allow to conrol narrow

beam with subsequent its scanning. That case, the effectivity of the system, consisting of only a pair of the deflecting electrodes, is very low.

Principal components of known electron-optical systems are a cathode ensemble, that includes at least one emitter, an anode, a film gate electrode, and a focusing system; the gate electrode and the focusing system being arranged between the cathode ensemble and the anode separated one from another by electrically-isolating layers.

An integration of focusing electrostatic lenses with the gate electrode and with the cathode at the same substrate was technologically implemented in the patent [3]. However, such an approach is effective only in some cases of cathode formation.

It is known an approach to realization of a flat-panel emission device [4]. The device includes a matrix electron-optical system consisting of at least two electron-optical systems; each of them includes a cathode ensemble (containing, at least, one emitter), a gate electrode, a focusing system, a deflecting system, and an anode. The approach gives, however, just a combination of conventional kinescopes resulting in a cumbersome, highly- energy-consuming, expensive device and is not acceptable in the cases where the aim consists in fabrication of cheap flat-panel displays having thickness 1 to 2 cm and consuming a small amount of energy. Such a design can not be considered as that relting to the flat panel displays. Such an approach has been earlier proposed in the patent [5], where a similar combination of screens was considered.

There are known devices for optical representation of information (displays) [4] that contain a matrix electron-optical system including, at least, two electron-optical systems. Each of the systems includes a cathode ensemble (containing at least one emitter), a gate electrode, a focusing system, a deflecting system, and an anode; the latter consists of a glass substrate, a phosphor layer, and a conducting- transparent-film layer. The layer can be of two versions, with a continuous + grid-like, or a segmentary + grid-like coatings, the segments being connected each to other. The device have the same drawbacks as the above-listed matrix electron-optical systems.

The display proposed in this invention has the advantages of the above-listed devices and, at the same time, has not the drawbacks. It is technologically simple for implementation, because technological procedures widely applied in electronic industry (such as photolithography, integration of several components in one module, matrix principle of fabrication, etc) are used at its realization. Owing to the modutness, this approach allows to fabricate devices of any sizes. At the same time, it is sufficiently original and, on this reason, solves the above problems that were not solved by other designs of the devices. In fact, this is a new stage in the technological integration of the modules of the emitting devices.

The integration proposed in this invention consists in preparation of cathodes or matrices of the cathodes on a separate substrate. This approach expands significantly a spectrum of the cathodes used in the emission device and, at the same time, does not limit the spectrum by initially

determined parameters. If take into account that the creation of the cathodes is principal in the emission devices, the approach proposed is of great importance. In this approach, three modules - those of cathode, of gating- focusing-deflecting, and of anode, are prepared separately and, then, combined in a united device. In such an approach, yield of the combined (united) devices is increased because, usually, combination of different procedures multiplies defectness (spoilage) of the product, whereas the preparation of the cathode ensemble is a critical procedure that complicates all the technology.

DISCLOSURE OF THE INVENTION

According to the invention, the emission device represents an electron- optical system that contain a cathode ensemble with at least one emitter, an anode, a film gate electrode, together with the focusing system, placed between the cathode ensemble and the anode, the gate electrode and the focusing system being separated one-from-another by isolating layers and, in the electron-optical system, between the focusing system and the anode is introduced a deflecting system implemented as a united (single-whole) separate electrode module, together with the gate electrode and the focusing system, that deflects the electron beam of the electron-optical system for an angle α , where the angle is counting off a vertical line connecting the center of the cathode ensemble and the nearest point of the anode, the angle is between 0° and 90°.

In the electron-optical system, the cathode ensemble can be implemented, together with a substrate, as a field emitter, or a photocathode, or a secondary field emitter, or a thermionic cathode. The gate electrode can be implemented as a perforated dielectric plate whose openings are covered with a conducting film grid.

The focusing system contains more than two film electrodes that have potentials, different in value and sign. The potentials are chosen so that the force lines of the electric field from the anode form a cupola in the space of the cathode ensemble, that covers all the cathode ensemble, and the apex of the cupola is at the level of the last electrode of the focusing system on the way of electrons that move from the cathode.

The focusing and deflecting systems are implemented as electromagnetic windings.

The deflecting system can be implemented as a multistage system of film electrodes with a profile as a straight line, and also as a line concave into the anode-to-cathode space and as a line convex out the anode-to-cathode space, the electrodes being placed along the trajectory of the electron beam that moves from the cathode and is accelerated in the electric field of the anode. Another point of the invention includes a matrix electron-optical system that contains at least two electron-optical systems. Each of the latter systems includes a cathode ensemble that contains at least one emitter, a

gate electrode, a focusing system, a deflecting system, and an anode. The gate electrode is of film nature, whereas the focusing system and the deflecting system of all the electron-optical systems are connected by isolating layers so that the components form a united (single whole) separate matrix- electrode module.

In the matrix electron-optical system, cathode ensembles of all the electron-optical systems are implemented on a single whole substrate regularly and in a system mode. Each of the electron-optical systems can be realized according to the above-described design. In particular, the deflecting system of each of the electron-optical systems is implemented as a system of electromagnetic windings, whereas between the matrix-electrode module and the anode is placed a conical spacer whose basis is positioned on the boundary of two electron-optical systems. The deflecting systems of all the electron-optical systems have separate or common electrical leads. One more point of the invention includes a device for optical representation of information (a display) that contains a matrix electron-optical system consisting of at least two electron-optical systems. Each of the latter systems includes a cathode ensemble, that contains at least one emitter, a gate electrode, a focusing system, a deflecting system, and an anode that includes a glass substrate, a phosphor layer, and a conducting-transparent- film layer, the latter containing two coatings, continuous and grid-like ones or segmentary and grid-like ones , and elements of the segmentary coatings are connected each to other. The gate electrode, of film kind, the focusing system, and the deflecting system of all the electron-optical systems are connected by isolating layers so that the components form a united matrix electrode module. In the first version of coating, the continuous coating is placed between the glass substrate and the phosphor layer. In the second version of coating, between the glass substrate and the phosphor layer is placed the grid-like coating. All of the electron-optical systems can be realized according to the above-described design.

The proposed design can work with a broad spectrum of cathodes such as field-, photofield-, thermionic-cathodes. According to this invention, such design become possible owing to their moduleness and because the techniques of their implementation are common for cathodes of all the types. The versatility is achieved by the fact that an integral electrode module, including the gate electrode, the focusing and deflecting systems, is placed between the anode and the cathode. For most devices, such an electrode module can be realized in an united technological process. The cathode ensemble can be presented by a single emitting point, as well as by a group of N emitting points, where N is a number from 1 and more. It can be presented by a single emitting tips, as well as by a group of K emitting tips, where K is a number from 1 and more.

Basing on this invention with the universal electrode module, it is posible to fabricate flat panel devices with various areas, for example, in the case of electron-emission displays, from several milimiters up to meters.

This invention can be also used for fabrication of memory equipments, if a matrix target, where is a material able to change its state under an action of the electron beam, is used as an anode.

Both the components of the proposed devices and their arrangements are of micrometer and of millimeter sizes. This simplifies significantly the technology of their fabrication and decrease their input capacity that ensures their good high-frequency characteristics..

A BRIEF DESCRIPTION OF DRAWINGS

The invention is illustrated by the following figures. Fig. 1 A,B. An electron-optical system, produced by the described earlier [3] integration technique for preparation of field-emission devices. 101 - a substrate for cathode ensembles.

102 - a cathode ensemble.

201 - a gate electrode.

202 - a system of film focusing electrodes. 204 - isolating layers. Fig. 2 A,B. A matrix electron-optical system produced by the described earlier [4,5] techniques for combination of plurality of screens into a united screen.

203 - a deflecting system.

208 - an angle α , a deflection off the "vertical". 300 - an anode.

Fig. 3. An electron-optical system produced by using of an electrode module 200 (point 1 of the "Claims"). 100 - a cathode module. 200 - the electrode module. 208 - the angle α , the deflection off the "vertical", 0° < α < 90°.

300 - the anode module.

Fig. 4. A matrix substrate with the cathode ensembles (see point 14 of the "Claims").

Fig. 5 A,B. A matrix electron-optical system where, in each separate electron-optical system, a function of the focusing system is implemented by a system of film electrodes with various potentials, whereas a deflection system is implemented as elecrtromagnetic windings (points 7 and points 9, as related to the point 7, of the "Claims").

202 - the electromagnetic windings of the deflecting system. 205 - a spacer between the matrix electrode module 200 and the anode.

Fig. 6 A,B,C - a matrix electron-optical system where, in each separate electron-optical system, the function of the focusing system is implemented by the system of film electrode with various potentials, whereas the deflection system is implemented as a system of film electrodes separated by isolated layers, the system having different profiles of the electromagnetic windings (point 7 and points 10, 1 1 , and 12, as related to the point 7, of the "Claims").

206 - a multistage system of film electrodes separated by isolating layers

Fig. 7 A,B - a matrix of electron-optical systems where, in each separate electron-optical system, the function of the focusing system is implemented by the electromagnetic windings, the deflecting system being implemented as electromagnetic windings (point 8 and point 9, as related to the point 8, of the "Claims").

207 - the electromagnetic windings of the focusing system.

Fig. 8 A,B,C - a matrix electron-optical system where, in each separate electron-optical system, the function of the focusing system is implemented by the electromagnetic windings, whereas the deflection system is implemented as a multistage system of film electrodes separated by isolating layers, the multistage system having different profiles (point 8 and points 10, 11 , 12, as related to the point 8, of the "Claims"). Fig. 9. An arrangement of separate miniscreens - of continuous areas of a transparent-film conductor, and of a grid of the(a) transparent-film conductor deposited along the perimeter of the miniscreen corresponding to each of the electron-optical system (point 16 of the "Claims").

Fig. 10 A,B. A structure of the anode in the cross-section A-A with two different arrangement of the transparent-film-conducting layers: according to the point 15 of the "Claims"- of continuous and grid-like ones; and according to the point 16 of the "Claims"- of segmentary and grid-like ones.

301 - a phosphor;

302 - the continuous-transparent-thin-conducting layer; 303 - the segmentary-transparent-film-conducting layer

304 - the grid-like transparent-film-conducting layer;

305 - a glass.

A MOST SUITABLE VERSION OF THE INVENTION

Currently, at fabrication of emission devices [6], a problem is that different screen areas are luminescent variously, and at each of such areas, a luminescence of individual emitters can be observed, the luminescence being accompanying with a flickering (glimming) nearby a principal position of the luminescent point.

The module version of the emission device, as it is proposed in this invention. This allows to control the emission current and to have either the luminescence or its absence, instead of the non-controlled flickering; this allows to focus the electron beam emitting by the cathode, to accelerate and to deflect it for a necessary angle ensuring the luminescence at a given point of the screen.

Another problem in the production of the emission devices consists in the fact that some cathode materials have rather large work function that makes it necessary to use high controlling voltages for overcoming the potential barrier by electrons.

The module 200 proposed here allows, by choosing a geometry of the module and specifying its components for each of the cathode types, and by calibrating of its principal systems such as gate, focusing, and deflecting electrodes, to reach a maximal result. This invention allows (in the case of displays) to fabricate high- resolution miniscreens (minidisplays) with sizes as small as 25 square mm (5 mm by 5 mm). To this aim, the only one cathode ensemble is necessary. An emitting electron beam from such a cathode will be treated by one-cell integral module 200 which, after some transformation, will implement scanning of the beam into an information picture that will be represented at the miniscren (minidisplay).

The technology proposed in this invention allows to produce emission devices with large screens without any principal limitation. Below, such a matrix device (a matrix electron-optical system).

AN EXAMPLE

(a) On a single-crystalline silicon wafer-substrate with the sizes 196 square mm = 14 mm x 14 mm, by a technique described in [6], a matrix 1 , that consists of cathode ensembles (3 rows by 3 cathode ensembles in each row, each of the ensembles containing 9 (3x3) emitter tips) is fabricated, see Fig. 4. The distance between the cathode ensembles is 4 mm.

(b) Four (or any other number) of matrices 1 , prepared according to (a), are installed onto an isolation (for example, glass) substrate so that to obtain a complete matrix 2 - module 100 consisting of 36 (6x6) cathode ensembles.

(c) According to the prepared cathode module 100, it is produced an integral electrode matrix (with emitter tips prepared according to the above- described technology) - the module 200 with the number of cells 36, symmetrically to the cathode ensembles prepared according to (b). The module 200 is put on the matrix by the gate electrodes down so as it is shown in Figs. 5, 6, and 7.

(d) Against the design prepared according to the (c), the last module 300 of a given design - the anode, shown in Fig. 9, prepared as modules 100 and 200, is installed.

(e) The structure prepared according to the sequential operations (a) to (c) is installed into a vacuum-tight chamber. The chamber has electrical leads of the cathode, gate electrodes, focusing and deflecting systems, and anode. It is pumping and sealing.

LITERATURE

1. Kawauchi, Yoshikazu et al, Flat configuration cathode ray tube, EP 0 336 449 B1 Date of publication 30.08.95 Bulletin 95/35

2.Suzuki, Hidetoshi et al, "Driving method for an electron beam emitting device", EP 0 628 982 A2

Date of publication 14.12.94 Bulletin 94/50

3. Kane, Robert C. et al, "Method of forming a field emission device with integrally formed electrostatic lens", EP 0 545 621 B1.

Date of publication 06.09.95, Bulletin 95/36

4. Shigeo Takenaka et. al, "Color cathode ray tube", US Pat. 4 792 720. Date of Patent 20.12.88

5. A.Weldorf, "Plural beam cathode ray tube", US Pat. 3 071 706.

Date of Patent 01.01.63 6. E.I.Givargizov et al, Field emission cathode and a device based thereon, Russian Patent 2074444, priority of 25.07.94; EP Application 726589.

Date of publication 14.08.96.