Duro-test Corporation

Ronald C Koo

Peter J Walsh

Joel Shurgan

Luke Thorington

Wolfgang E Thouret

An incandescent lamp having a transparent heat mirror placed on the lamp envelope which transmits a substantial portion of the energy in the visible range produced by the lamp filament and which reflects back to the filament at least about 80%-85% of the infrared energy that the filament produces. In the preferred embodiment the transparent heat mirror is formed by a layered coating of TiO.sub.2 /Ag/TiO.sub.2 optimized for the operating temperature range of the filament. The filament is constructed to optically conform to the shape of the lamp envelope.

Incandescent light source with transparent heat mirror

A high intensity discharge lamp in which the arc tube is located within an outer envelope. A multi-filament assembly is located within the outer envelope in series with the current supply to the arc tube. When the lamp outer envelope is broken, the filaments will burn out in the presence of air, open the current supply to the arc tube and extinguish the arc. The use of multi-filaments permits better control of the filament burn out time.

High intensity discharge lamp with multiple filament to extinguish lamp

An annealed tungsten filament wire for electric lamps having substantially the same amounts of impurities therein as was present prior to annealing.

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Weehawken, NJ, United States of America

Ronald C Koo