Koninklijke Philips Corporation N.v.

Antoon Joseph Bock

Peter Luerkens

Wilhelmus Hinderikus Maria Langeslag

Guenther Hans Derra

Hubertus Cornelis Maria Van Den Nieuwenhuizen

Johannes Martinus De Regt

Ulrich Böke

Dirk Paul Joseph Vanderhaeghen

A ballast arrangement is provided for igniting and operating a discharge lamp. The lamp is connected in a commutating bridge in series with an inductor and parallel to a capacitor. The inductor and the capacitor together form a resonance circuit. During ignition, the bridge is commutated at a comparatively high frequency that changes with respect to time. The series resonance circuit has a resonance frequency that is close to an odd harmonic of the comparatively high frequency.

Circuit arrangement

The invention relates to a background lighting system for a liquid crystal display, more particularly to an electronic circuit for operation of one or more discharge lamps. A DC/AC full-bridge inverter circuit generates two voltages whose AC components are phase-shifted by 180&#xb0;. The discharge lamps are supplied with the sum of these two AC voltages.

Circuit arrangement for operation of one or more lamps

The invention relates to a high-pressure discharge lamp provided with a discharge vessel made of glass which encloses a discharge space having an ionizable filling and an electrode. The discharge vessel is provided with a seal which encloses an Mo foil having knife edges and forms a feedthrough for an electric conductor to the electrode. At the location of the foil, the seal has a gastight sealed cavity and a first antenna on the outer side of the cavity. Preferably, a second antenna is placed at the neck where the seal is connected to the discharge vessel. This reduces both hot restrike voltage and hot restrike delay.

High-pressure discharge lamp having seal with external antenna

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Landgraaf, Netherlands

Antoon Joseph Bock