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US 4,049,988 AGranted
Tungsten halogen lamp
AssigneeGTE Sylvania Incorporated
InventorJames P. Keenan
Life of this patent
Estimating the term…
Abstract
Helium is added as a component of the gaseous filling of a tungsten halogen lamp in order to prevent deposits from forming on the walls of the lamp envelope.
Claims3
In a tungsten halogen lamp of the type where normal lamp operation does not permit attainment of a sufficiently high envelope wall temperature to prevent deposits from forming on the envelope walls, the improvement which comprises providing sufficient helium as a component of the lamp gaseous filling to prevent said deposits from forming, said helium being 20 to 50 volume percent of the total gaseous filling.
Dependencies are inferred from the claim text.