U.S. Philips Corporation

Andreas P Sneijers

Jacobus M Claassens

Roger J Van Den Plas

The invention relates to a high-pressure discharge lamp comprising a discharge vessel enclosing a discharge space and provided with two main electrodes. Each of the main electrodes is connected to a lead-through element which is enclosed with an intermediate space by a closing part and is connected thereto in a gas-tight manner by means of a sealing joint. According to the invention, the lead-through element is provided with a protuberance reaching as far as the closing part and being present around the whole periphery of the lead-through element. In this manner, a screening of the sealing joint from the discharge space is obtained.

High pressure discharge lamp

The invention relates to a high-pressure sodium lamp which is provided with a discharge tube having an external auxiliary electrode. The auxiliary electrode is switched off by a bimetallic switch in the operating condition of the lamp. According to the invention the lamp also comprises a glow starter which in the operating condition of the lamp is switched off by means of the same bimetallic switch. This apparatus achieves in a simple manner, a large available voltage for igniting the discharge tube with an operating condition of the lamp in which no disturbance is experienced from any of the ignition auxiliary means.

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Eindhoven, Netherlands

Andreas P Sneijers