U.S. Philips Corporation

Jan W Denneman

Pieter Postma

Henk Houkes

Jan Willem Dorleijn

Rudolf L Van Der Heijden

Petrus F Wouters

Hendrik B Van Dam

A method of and a device for the operation of a high-pressure discharger lamp provided with a discharge vessel (3) which accommodates an ionizable filling and two electrodes (4, 5), between which electrodes in the operating condition the discharge takes place. The lamp is operated from a supply source which supplies a power of periodically alternating value. According to the invention, for each power frequency .nu..sub.i (i=1,2, . . .) the relation .nu..sub.i .gtoreq.60 .nu..sub.1 is satisfied, where .nu..sub.1 is the lowest frequency at which in the operating condition of the lamp standing pressure waves can occur in the discharge vessel (3). Thus, it is possible to operate the lamp so as to be free from arc instabilities due to standing pressure waves.

Method of operating a high-pressure discharge lamp

A discharge lamp having a sealed glass vessel filled with gas and a metal vapor, operated with a supply at a frequency of at least 20 kHz. An interference-suppressing conductive layer is arranged on a wall surface surrounding the discharge, and connected to an electric supply lead-in wire. Preferably, a plurality of insulated metal rings, on the outside of the wall, also surround the discharge.

Discharge lamp with interference shielding

An electrodeless gas discharge lamp having a closed loop core of a magnetic material the part of which core extends through the lamp vessel, a high frequency field being induceable in this core by means of an h.f. generator in the lamp base, said core is assembled of at least two operable core portions at least a major part of one portion lying within the lamp vessel, and the other of the two portions being located in the lamp base, the lamp base being detachably secured to the lamp vessel.

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Eindhoven, Netherlands

Jan W Denneman