U.S. Philips Corporation

Dirk Van Houwelingen

Johannes A Damsteegt

Johannes M Compen

Jozephus J Warringa

To test a cathode ray tube or an apparatus comprising a cathode ray tube, a part of the electron gun is heated by means of high-frequency electromagnetic radiation. By virtue thereof, the warm-up period, that is the time which, after turning on the cathode ray tube, must elapse before the testing operation can be carried out, can be reduced, for example, from approximately 30 minutes to approximately 2 minutes.

Method of manufacturing a cathode ray tube

A film provided on a cathode ray tube is cured by locally subjecting it to a flow of very hot air. The gas flow heats the film without heating the underlying display window. Said gas flow is used to scan the surface.

Method of curing a film

An electron tube, for example, a transmitter tube of the triode type, comprising in an evacuated envelope a mesh or cage cathode (3) and an anode (1). By providing a control electrode (4) near the cathode (3) on the side thereof remote from the anode (1), the output power of the tube can be controlled by means of a potential difference between the control electrode (4) and the cathode (3).

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Eindhoven, Netherlands

Dirk Van Houwelingen