Patent ID: 7755291

Claim:
An incandescent lamp that emits infrared light, comprising: a filament assembly inside a tubular polycrystalline aluminum oxide envelope, said filament assembly having a coiled tungsten filament, solid metal ends of tungsten or molybdenum attached to distal ends of said coiled tungsten filament and first and second leads at respective distal ends of said solid metal ends; polycrystalline aluminum oxide spacers disposed within the tubular envelope, each spacer having an opening through which the filament assembly passes, the coiled tungsten filament being stretched in regions where coiled tungsten filament passes through the spacers; end caps attached to ends of said envelope, wherein said end caps each have an opening through which a respective one of said first and second leads extends and wherein said first and second leads are each made of an electrically conductive material having a coefficient of thermal expansion compatible with said end caps; and glass-ceramic sealing frits that attach each of said first and second leads to a respective one of said end caps, wherein said end caps and said sealing frits seal a gas inside said envelope.