SU376826A1 - C P AND WITH A N AND E YOUR INVENTIONS - Google Patents

Description

one

The invention relates to electronic engineering.

Autoelectronic cathodes are known whose emitting surface is an end of a conducting film that is remote from a dielectric substrate.

In order to reduce the operating voltage, a conductive film is placed under the dielectric substrate near the emitting end of the cathode.

The proposed autoelectronic cathode is shown in the drawing, where: a) is a substrate, 2 is an insulating film, 3 is a cathode holder layer, 4 is a cathode film, 5 is an emitting edge of the cathode film, 6 is an electron collector, 7 is a starting conductive electrode. The arrows indicate the direction of movement of the electrons.

The cathode substrate 1 may be made of a conductive or non-conductive material, for example glass. The cathode film has a thickness equal to tenths or hundredths of a micron, and is made of mechanically strong conductive materials, such as tungsten, molybdenum, etc. The layer 3 of the cathode holder can be made of conductive or dielectric material, its thickness is determined The distance from the cathode film to film 2, the material for which is a dielectric with high electrical strength. The starting conductive electrode 7 is a thin film of any conductive material. Before starting work, the potential Uc relative to the cathode film is fed to the starting electrode. At the moment when the potential Uc is turned on, a capacitor formed by films of the starting and cathode electrodes as plates and an insulating film 2 in

dielectric will begin to charge. The intensity of the field in the insulating film 2 and the 1 vacuum gap between this film and the edge 5 of the cathode film is distributed inversely proportional to their dielectric constant, i.e., the strength of the field in the gap between the cathode film and the insulating film 2 is 8 times greater than an insulating film (e is the relative dielectric constant of film 2).

With a sufficient starting voltage Uc, autoelectronic emission of electrons from the edge 5 of the cathode will arise. The emitted electrons fall on the surface of the insulating film 2 with the energy determined by the drop in potential at the vacuum gap. If the coefficient of secondary emission of the surface of the film 2 is greater than 1, then the number of electrons knocked out will exceed the number caught on this surface, the surface will receive an additional positive charge.

secondary electrons will reach the collector 6. An additional positive charge on the surface of the film 2 will increase the field intensity at the cathode edge, which will increase the autoelectronic current, etc. The process goes avalanche and stops when the surface potential of the insulating film 2 becomes equal to the collector potential L / K. The field strength at the cathode edge (without taking into account the field gain due to the edge effect) will be equal, where d is the distance between the emitting edge and the film 2. The edge effect will enhance the field corresponding to the sharpness of the film edge. At the moment when the process of the avalanche-like buildup of the emitted current stops, the effective secondary emission factor of film 2 becomes equal to 1, i.e. the number of electrons emitted by the cathode is equalized with their number falling on the collector. The material of the dielectric film 2 must have a secondary emission coefficient greater than 1 at low operating voltages, such as magnesium oxide and other oxides. Since the distance d (equal to the thickness of the cathode holder) can be made very small, up to a hundred or less angstroms, without the danger of closing the cathode with the starting electrode, the intensity at the edge of the cathode can be increased to the necessary order value CM with a working voltage of 50 b and less.

The method of manufacturing thin film nribor. For example, with one option for the whole

The surface of the dielectric substrate 1 is successively sprayed in layers of vacuum 7, 2, 3, 4, then a layer of photoresist is applied and using photolithography, windows or slits are cut in the upper layer 4 to form the emitting edges 5.

The next step is to etch the windows with IB layer 3, and a cathode film is used as the resist. Etching

lasts until a slight undercutting under the edges of the cathode film. The material of layer 3 can be either dielectric or conductive; it is advisable to choose it so that when it is etched does not occur

corrosion of the cathode. For example, if the cathode material is tungsten, then molybdenum can be chosen as the material of layer 5.

The cathode can be used as a source of electrons instead of an oxide cathode in electronic devices such as PUL, kinescopes, oscilloscopes, etc.

Subject invention

The autoelectronic cathode, the emitting surface of which is an end-to-end conductive film remote from the dielectric substrate, is characterized in that, in order to reduce the operating voltage and increase the stability of operation, a conductive film is placed under the dielectric substrate near the output end of the cathode tension