DE1054594B - Metal-ceramic tubes and method for applying a resistance layer to the inner surface of a ceramic ring for such a tube - Google Patents

Description

The invention relates to a metal-ceramic tube, which consists of a layered structure of alternating successive metal and ceramic disks or rings, the metal disks or -ring represent the connection contacts for the electrodes housed inside the tube, and a Method for applying a resistive layer to the inner surface of a ceramic ring for a such tube.

Particularly high requirements are placed on such discharge tubes in certain applications with regard to high ambient temperatures, vibrations or impacts. Furthermore, such Tubes sometimes work in an environment that is exposed to nuclear radiation. Same requirements are now placed on the circuit elements with the electrical discharge tubes are interconnected.

According to the invention it is proposed that one or more of the usual Circuits belonging to resistors as resistive layers on the inner surfaces of the ceramic rings of the Tube are applied. It can be, for. B. to circuit resistors, such as the. Anode resistance and the grid-cathode resistor, which are designed as inner coverings of the insulating parts of the discharge vessel, so that on the one hand the initially The conditions set also with regard to these circuit parts are fulfilled and, on the other hand, a Number of connecting lines is saved.

It is already known per se to have resistors belonging to circuits as resistance layers to apply to the inner surfaces of electron tubes. For example, one has to achieve a continuous Course of the post-acceleration field in a Braun tube in tube piston two Metal rings attached at a certain distance from each other and both metal rings connected to each other by a resistance layer. In this well-known Arrangement, the resistance layer has the task of creating a linear potential gradient between the two Manufacture metal electrodes. The resistance layer is thus directly attached to the structure of the field within involved in the tube.

Furthermore, it is also already known to use insulating parts in a tube to cover a conductive layer in order to prevent charges or undesired voltage distributions on this insulating body.

In contrast to the known arrangements, the resistance layer in the arrangement according to the invention has has nothing to do with the field build-up inside the discharge tube. It is within other processes the discharge tube is usually not involved at all.

Metal-ceramic tube
and method of application
a resistance light
on the inner surface of a ceramic ring
for such a tube

Applicant:

General Electric Company,
Schenectady, Ν. Υ. (V. St. A.)

Representative: Dr.-Ing. Β. Johannesson, patent attorney,
Hanover, Göttinger Chaussee 76

Claimed priority: V. St. v. America September 4th 1956

Walter Grattidge ₁ Schenectady, NY (V. St. A.),
has been named as the inventor

Some embodiments of the invention are shown in the drawing.

Fig. 1 shows a longitudinal section of an electrical discharge tube and that designed according to the invention Circuit parts; in

FIG. 2 shows the circuit arrangement which is achieved by a structure according to FIG.

According to the exemplary embodiment according to FIG. 1 ', the tube arrangement consists of a triode system, which contains the anode resistance and the grid-cathode resistance; both resistors are arranged in the array in such a way that connections to the electrodes are made during manufacture of the array. The stacked structure includes annular insulating members 10-13 and conductive connecting members 14-18; these members are alternately arranged and cemented together, so that they result in five isolated connections, the distance between which is determined by the insulators. The whole forms a vacuum-tight ^p- eye envelope. The ceramic insulators can be made of a material - which appears suitable for -electrical discharge tubes. For this purpose are preferred Aluminum oxide body or body made of a ceramic material used, whose coefficient of expansion is comparable to that of titanium. The ceramic bodies are of high purity and give off very little gas when they are on a

809 789/401

Claims (5)

stand to reduce the oxide to a desired extent and thus affect the resistance of the film. This supply of hydrogen can take place through the presence of titanium hydride, which is exposed to the interior of the arrangement. Since titanium hydride is required in a particularly preferred method for assembling the tube envelope of such a layered arrangement, this provides a suitable way of keeping the necessary between the surface of the insulator 12 and the agile hydrogen for the reduction of the oxide grid connection 16. Get the cathode 21. sits in the shape of an overturned cup, the In Fig. 2 is the schematic diagram of the upper surface 22 is located in close proximity to the grid of different parts arranged in the tube again-22. The cathode member 21 is given at its upper one. These parts are identified by a number corresponding to FIG. 1 with an electron-emitting material 15. It is he temperature of several hundred degrees to be heated. The connecting members are made of a conductive material, titanium and copper have proven to be particularly useful. The various electrodes of the arrangement are located in the axial direction within the vacuum vessel. The anode 19 can be made in one piece with the anode connection 15; the grid 20 is supported by a grid ring which is coated 30-35, e.g. B. an alkaline earth oxide. This cathode member is heated to the emission temperature with the aid of a resistance heating element 23. One end of the heating element 23 is connected to the center point of the bottom of the Katfliodeelementes 21, while its other end leads to the heating connection 18. According to the invention, the inner wall of the insulator 12, which surrounds the cathode 21, is provided with a coating 24 which represents a resistor which connects the ring carrying the grid and the cable sleeve to one another. Similarly, the insulator 10 is provided with a resistive coating 25 on its inner surface which lies between the conductive disks 14 and 15. These resistance layers are obtained by applying a coating to the corresponding surfaces which is reduced during the heating and melting of the tube arrangement. The resistance is then determined by the nature of the coating and the process to which that coating is subjected. While the resistive coatings 24 and 25 can be produced by a variety of methods, depending only on the desired resistance characteristics, the grid-cathode resistor 24, which has a resistance of 1000 to 100,000 ohms, but preferably one of 10,000 ohms, can advantageously be produced by the following process: The surface of the ceramic to which the resistance film is to be applied, in particular the inner wall of the ceramic insulator 12, is coated with a mixture of about 30% iron and 70% titanium hydride ( Weight percent) in a binder containing a carbonaceous component, e.g. B. nitrocellulose, contains, coated. One of the advantages of such a coating is that it can be made during the pumping and fusing process of the entire assembly. In many applications it is desirable for the grid-cathode resistance to have a significantly higher value than is obtained with the method described. If such a resistance in the order of magnitude of 1 to 100 Ω is desired, it is advisable to use the following method: The inner wall of the insulator 12 is coated with an oxide, e.g. B. Fe2O3, TiO2 or ZrO2, which is evident in that the arrangement shown in Fig. 1 represents the basic combination that contains a triode and the anode-cathode Wi the stand. The whole arrangement can be used at high temperatures, e.g. B. at temperatures that exceed 500 ° C, operated. The invention can also be used for the production of circuit arrangements with a stacked structure of the individual parts. Patent claims: 1. Metal-ceramic tube, consisting of a layered structure of alternating successive Metal and ceramic disks or rings, the metal disks or rings being the Represent connection contacts for the electrodes housed inside the tube, characterized in that that in a manner known per se one or more belonging to conventional circuits Resistors are applied as resistance layers on the inner surfaces of the ceramic rings. 2. Metal-ceramic tube according to claim 1, characterized in that already existing electrode connections or additional connections also designed as metal disks are used as connections for these resistors. 3. Metal-Kerami'k tube according to claim 2, characterized in that several electrode systems in the layered design are arranged one above the other and axially to one another. 4. Method of applying a resistive layer to the inner surface of a ceramic ring for a metal-ceramic tube according to the claims.! to 3, characterized in that the ceramic surface with a binder in a carbonaceous, e.g. B. nitrocellulose, dissolved Powder from a mixture of 30 percent by weight iron and 70 percent by weight titanium anhydride will. 5. Method of applying a resistive layer to the inner surface of a ceramic ring for a metal-ceramic tube according to claims 1 to 3, characterized in that the Ceramic surface with a suitable organic binder, e.g. B. Zaponlack, dissolved 40 45 55 a suitable organic binder, e.g. B. Zapon, is coated; the insulator so coated becomes then heated. During this process, a hydrogen-generating substance must also be available 65 oxide, for example Fe ₂ O ₃ , TiO ₂ , ZrO ₂ , is coated, and that this coating layer is then heated in the presence of a hydrogen-releasing substance. Considered publications: German Patent Specifications No. 715 038, 732 513, 726, 684 750, 917 680, 676 367, 750 219; U.S. Patent No. 2,183,302. 1 sheet of drawings & 809 789/401 3.5 »