Chemically polished polycrystalline alumina material
AssigneeGeneral Electric Company
InventorsGarland E. Scott, Jr., Michael K. Levenson
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Abstract
Increased optical transmission is provided for a body of light transmissive polycrystalline alumina body treated at elevated temperatures with a molten flux composition. A tube of the flux polished material which can be used as the light transmissive envelope for high intensity discharge lamps especially sodium vapor lamps, improves light output from the lamp as the result of increased in-line transmission for the treated envelope member. A method of chemically polishing polycrystalline alumina material in this manner is also disclosed.
Claims6
An improved high intensity electric discharge lamp comprising a light transmissive envelope having electrodes sealed into its ends and containing an ionizable medium for carrying the discharge, wherein the improvement comprises utilizing as the light transmissive envelope a tube consisting essentially of high density, polycrystalline alumina having the major exterior surfaces flux polished so as to reduce the high spots on the individual exterior alumina crystals without materially etching grain boundaries and thereby to obtain increased optical transmission upon flux removal.
Dependencies are inferred from the claim text.