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US 4,539,505 AGranted
Candoluminescent electric light source
AssigneeGTE Laboratories Incorporated
InventorLeslie A. Riseberg
Life of this patent
Estimating the term…
Abstract
An electric lamp has a candoluminescent filament. The filament has a resistive core which is heated electrically. Infrared radiation emitted by the resistive core is converted to visible light by a sheath of candoluminescent material surrounding the resistive core. The filament may be a sintered composition of carbon, ceric oxide and thorium dioxide. Carbon proximate to the surface of the filament is removed by oxidation, leaving a closed pore structure of candoluminescent material.
Claims6
An electric lamp comprised of:
- a light passing envelope;
- at least two lead-in wires extending from the exterior to the interior of said envelope;
- a filament supported within said envelope by said lead-in wires, said filament including a resistive core electrically coupled to said lead-in wires;
- and
- a candoluminescent sheath at least partially surrounding said core;
- wherein
- said resistive core is a sintered composition including carbon, ceric oxide, and thorium dioxide;
- and
- said candoluminescent sheath is a sintered composition including ceric oxide and thorium dioxide.
6 more elements
A filament for use in electric lamps comprised of:
- a resistive core;
- and
- a candoluminescent sheath surrounding said core;
- wherein
- said resistive core is a sintered composition including carbon, ceric oxide, and thorium dioxide;
- and
- said candoluminescent sheath is a sintered composition including ceric oxide and thorium dioxide.
4 more elements
Dependencies are inferred from the claim text.