Koninklijke Philips Corporation N.V.

U.S. Philips Corporation

Fransiscus Arnoldus Vermeulen

Josephus Christiaan Maria Hendricx

Johannes Jacobus Franciscus Geijtenbeek

Joseph Leonardus Gregorius Suijker

Antonius Arnoldus Duisters

Johan Leopold Victorina Hendrix

Johannes J Geijtenbeek

Johannes J F Geijtenbeek

A method for driving a lamp is described includes generating a light controlling DC electric field E with a desired direction and a desired strength inside the lamp such as to obtain a desirable ion distribution inside the lamp. The lamp is supplied with a commutating current with a DC component, having a constant current intensity and a duty cycle differing from 50%. By setting the duty cycle, it is possible to set a certain average value of the lamp current, allowing the efficacy and/or color temperature of the lamp to be influenced.

Method and device for driving a metal halide lamp

A metal halide lamp () is described, the lamp being designed such that, when the lamp is operative in a vertical orientation, the location of the salt pool is close to the top of the discharge chamber (). In an embodiment, the coldest spot is close to the top of the discharge chamber. Means are provided enabling more heat to be supplied to the bottom part than to the upper part. In a lamp assembly (), comprising a lamp () arranged inside a bulb (), additional heat generating means () may comprise a radiation coil ().

Gas discharge lamp

Metal halide lamps have a discharge vessel operable at a high coldest spot temperature. The discharge vessel encloses a discharge space comprising an ionizable gas filling and, in addition to Hg, also an alkali iodide of Na of Li or a combination of both. According to the invention, the filling also comprises TbI3 or GdI3 or a combination thereof.

Metal halide lamp

Metal halide lamps are disclosed having a discharge vessel with a ceramic wall. The discharge vessel encloses a discharge space comprising an ionizable gas filling and, in addition to Hg, an alkali iodide of Na or Li or a combination of both. The filling also includes TbI or GdI or a combination thereof.

Metal halide lamp includes a discharge vessel having a ceramic wall with an internal diameter Di and enclosing two electrodes whose tips are a distance EA apart, wherein EA/Di>5. The vessel has a filling comprising Hg, CeI, and LiI.

Metal halide lamp with lithium and cerium iodide

Metal halide lamp includes a discharge vessel having a ceramic wall with an internal diameter Di and enclosing two electrodes whose tips are a distance EA apart, wherein EA/Di&gt;5. The vessel has a filling comprising Hg, CeI, and LiI.

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Eindhoven, Netherlands

Fransiscus Arnoldus Vermeulen