U.S. Philips Corporation

Pieter Hendrik Broerse

Johannes A Van Vliet

Louis E Vrenken

Markus Wilhelm Wanninkhof

Johnny Wilhelmus Van Der Velden

A metal vapor discharge lamp includes a discharge tube with main electrodes at each end. A starting electrode extends around at least an axial portion of the tube intermediate the main electrodes, one main electrode is connected to the starting electrode by a first resistance and the other main electrode is connected to the other electrode by a second resistance. At least one of the resistances has a temperature dependent characteristic which is substantially more positive than the other resistance.

Electric device provided with a metal vapor discharge lamp

A flash array which is provided with a transparent electrically conductive layer which serves to prevent spontaneous ignition of a flash lamp in the device. The flash array is provided with high voltage combustion flash lamps and the transparent electrically conductive layer consisting of conductive indium oxide which is applied to the inner side of a transparent cover of the array. The resistance per square of that layer is smaller than 100 kOhm, so that for these lamps -- which are, for example, ignited by means of a piezo element -- substantially no spontaneous ignition occurs.

Flash array

In a lighting fitting provided with at least two low-pressure mercury vapor discharge lamps whose radiated light has a different spectral composition. The lighting fitting is provided with apparatus to control the lumen ratio of the two lamps without varying the lumen level of the fitting. According to the invention low-pressure mercury vapor discharge lamps are used in the fitting which, inter alia as regards their color point, satisfy special requirements so that the color rendition obtained with these lamps is always of a high quality for each mixing ratio of the light from these lamps.

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Eindhoven, Netherlands

Pieter Hendrik Broerse