Osram Gesellschaft MIT Beschraenkter Haftung

Patent-treuhand-gesellschaft F. Elektrische Gluehlampen Mbh

Osram Gmbh

Andreas Ponnier

Bernhard Altmann

Ralf Seedorf

Lothar Vollmer

Juergen Maier

Andreas Naujoks

Jürgen Becker

Juergen Begemann

Detlef Günther

A method for producing a molybdenum film for lamp construction is provided. The method may include roughening at least a part of the surface of the molybdenum film by sandblasting with a sandblasting means, wherein the sandblasting means contains at least one of aluminum oxide and quartz sand as well as at least one further component.

Method for producing a molybdenum film for the construction of a lamp and molybdenum film and lamp with molybdenum film

To improve the arc stability of high-pressure discharge lamps, particularly f power ratings of up to about only 250 W, the cathode (4) is formed as an elongated, essentially cylindrical base body (8) having a tapering, conical region (9) terminating in a tip (10). The base body (8), only, is covered with a carbide coating along its length, except for an end portion for electrical connection; the carbide coating starts at the junction or transition between the cylindrical base body portion and the conical end portion. This cathode construction is easier and cheaper to make than prior art cathodes, by coating an essentially cylindrical cathode and then etching or grinding and polishing the tapering end region (9). The electrode is preferably made essentially of tungsten, doped with thorium oxide present up to about 0.6%, optionally also potassium, aluminum and silicon in tiny amounts. The electrode spacing is between 0.4 to 0.8 mm, and when used as a mercury high-pressure discharge lamp, filled with 70 to 130 mg per cubic centimeter mercury; when used as a xenon lamp, the xenon fill is preferably present at a cold fill pressure of between about 2 and 15 bar.

High-pressure discharge lamp, particularly low-rated power discharge

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Berlin, Germany

Andreas Ponnier