U.S. Philips Corporation

Berthold Frank

Bernhard N Lersmacher

Georg Friedrich Gartner

Hans J Lydtin

Hans-Jurgen Lydtin

The cathode (4) the material of which is substantially high-melting metal such as W, Mo, Ta, Nb, Re and/or C, consists of a very fine-grained mechanically stable support layer (5), a series of layers (6) considerably enriched with emissive material, in general from the scandium group especially from the group of rare earth metals, preferably with Th or compounds thereof and a thermally stable preferentially oriented coating layer (7). All the layers are provided via the gaseous phase, for example, CVD methods, on a substrate (1) formed according to the desired cathode geometry. The substrate (1) is removed after termination of the deposition. FIG. 2.

Method of manufacturing a thermionic cathode and thermionic cathode

The undulation of hot-moulded glass is avoided when the cooling of the glass edge layers in the first phase of the moulding operation is delayed and is accelerated after completed moulding. This is achieved by using a mould of a glassy carbon having a porous structure. Prior to the moulding, the pores are filled with a gas-forming liquid or a gas. The resulting gas film between the glass and the surface of the mould is removed ater completed moulding. The pores may subsequently be filled with a cooling agent.

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Aachen, Germany

Berthold Frank