U.S. Philips Corporation

Koninklijke Philips Corporation N.V.

Forschungszentrum Julich Gmbh

Philips Intellectual Property & Standards Gmbh

Marcus Kubon

Robert Peter Scholl

Dorothea Seebode

Paul Hellwig

Joseph Franciscus Raymond Eijsermans

Manfred Peterek

Magnus Kolter

Juergen Schoeneich

Angela J&ouml;rres

Joseph F R Eijsermans

Claus Beneking

Hermann Krautzberger

A discharge lamp is disclosed comprising an enclosed discharge vessel for the generation of an electrical discharge and a casing made of glass which surrounds the discharge vessel. In order to achieve as constant properties as possible over the service life of the lamp, it is proposed that the glass material of the casing be doped with sodium in a concentration of at least 10 ppm, and preferably at least 30 ppm. According to a further embodiment, it is proposed that other alkali metals (except for sodium) be contained in a maximum concentration of 25 ppm. Surprisingly, by the appropriate choice of the outer bulb, not in direct contact with the actual discharge, the diffusion of sodium from the discharge vessel is reduced. In addition to this, the material of the outer bulb has a reduced inclination to crystallization.

Discharge lamp and outer bulb therefor

Tungsten electrodes are arranged on two rhenium rods in an electrode chamber in a high-pressure gas discharge lamp, such that the rhenium rods project to inside the electrode chamber.

High-pressure gas discharge lamp

The high-pressure discharge lamp comprises a sealed lamp vessel ( ) having a quartz glass wall ( ) enclosing a discharge space ( ). Metal foils ( ) are embedded in the wall, connected to electrode rods ( ) projecting from the wall into the discharge space. The electrode rods ( ) have a first part ( ) and a second part ( ) with a diameter of between 250 and 350 &mgr;m and at least an envelope ( ) made of rhenium. The second part, which is positioned within the wall ( ), prevents premature failure of the lamp caused by leakage.

High pressure discharge lamp with tungsten electrode rods having second parts with envelope of rhenium

A high-pressure metal halide discharge lamp has opposed tungsten electrodes carried by electrode rods. These rods have a first portion of tungsten adjacent the electrodes and a second portion made of at least 25% by weight of rhenium. Their common boundaries are at a location having an operating temperature in the range of 1900-2100&deg; K. The gas filling contains metal oxyhalide and is devoid of rare earth metal compounds.

High-pressure metal halide lamp having three part electrode rods

The high-pressure metal halide discharge lamp has opposite tungsten electrodes (5) carried by electrode rods (7). These rods (7) have a first portion (71) of tungsten adjacent the electrodes (5) and a second portion (72) having a core of tungsten and a skin of at least 90% by weight of rhenium. Their common boundaries are at a location having during operation a temperature in the range of 1900-2100 K. The gas filling contains metal oxyhalide and is devoid of rare earth metal compounds. The lamp has a long life and a high luminous maintenance.

Metal halide lamp with rhenium skin on tungsten electrode

Thin film solar cell

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Aachen, Germany

Marcus Kubon