Koninklijke Philips Corporation N.v.

Pieter Postma

Michael Haacke

Paul Hellwig

Ralf Muckel

Shin'ichi Honma

Juergen Schoeneich

A high-pressure gas discharge lamp includes at least a lamp tube and two electrodes. The two electrodes are each attached to the lamp tube by a sealed area and, outside the sealed area, each electrode has a perpendicular minimum distance, with respect to its longitudinal axis, from the lamp tube.

High-pressure gas discharge lamp

A high-pressure gas discharge lamp (HID [high intensity discharge] lamp) is described which is in particular free from mercury and suitable for use in automobile technology. The lamp is remarkable in particular for a discharge space () which has a volume which is reduced by a given factor in comparison with the volume of the discharge space of known mercury-containing discharge lamps. The quantity of the light-generating substances in the discharge space () is reduced by the same factor in the simplest case, or even more strongly. This avoids the risk of an impairment of the imaging properties of the lamp because of non-evaporated light-generating substances which may shade off a portion of the luminous discharge arc () and/or the tips of the electrodes ().

High-pressure gas discharge lamp with an asymmetrical discharge space

A device and a method for the control of a gas discharge lamp are disclosed. In order to detract as little as possible from lamp life in spite of the luminous flux requirements to be fulfilled during the run-up of the lamp, the lamp is operated with an alternating current in a run-up phase which comprises at least the interval from 1 s to 3 s after lamp ignition, the amplitude of said current rising during the run-up phase. After the rise in the run-up phase, the current may first rise further or remain constant in a transitional phase which preferably follows the former phase, and is subsequently reduced until the lamp enters the stationary operational phase. The time gradient of the current is preferably chosen such here that minimum values for the luminous flux of the lamp are achieved at given moments. Particular advantages are obtained, for example, in the case of Hg-free lamps which are operated with high currents, especially during the run-up.

Device and method for controlling a gas discharge lamp, and lighting system with gas discharge lamp and control device

A high-pressure gas discharge lamp (HID &lsqb;high intensity discharge&rsqb; lamp) is described which is designed in particular so as to be free from mercury and suitable for use in automobile technology. To achieve improved lamp properties, in particular a substantially equal luminous efficacy compared with lamps of the same power and having a gas filling with mercury, as well as a burning voltage which is as high as possible, a geometry is proposed for the discharge space ( ) which raises the temperature of the coldest spot in the lamp to such a degree that the light-generating substances can enter the gas phase to a sufficient extent also without mercury, and in particular in combination with the use of a metal halide as a voltage gradient generator.

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Roosteren, Netherlands

Pieter Postma