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US 4,302,699 AGranted
Low wattage metal halide arc discharge lamp having optimum efficacy
AssigneeGTE Products Corporation
InventorsWilliam M. Keeffe, Harold L. Rothwell, Jr.
Life of this patent
Estimating the term…
Abstract
A single ended metal halide arc discharge lamp contains mercury, sodium halide, scandium, scandium halide and a starting gas. The molar ratio of sodium halide to scandium halide is between about 5 to 8 in order to obtain optimum luminous efficacy.
Claims5
A single-ended low wattage metal halide arc discharge lamp comprising:
- an arc tube having a press seal at one end thereof, two main electrodes embedded in the press seal and extending into the arc tube, the arc tube containing mercury, sodium halide, scandium, scandium halide and a starting gas, the molar ratio of sodium halide to scandium halide during normal operation being between about 5 to 8 in order to obtain optimum luminous efficacy.
A single-ended low wattage metal halide arc discharge lamp comprising:
- an arc tube having a press seal at one end thereof, two main electrodes embedded in the press seal and extending into the arc tube, the arc tube containing an initial filling that includes mercury, sodium halide, scandium, a starting gas and a metal halide that reacts with scandium to form scandium halide, the reaction of said metal halide with scandium being substantially complete after about 100 hours of lamp operation, the molar ratio of sodium halide to scandium halide being between about 5 to 8 after said substantially complete reaction, there remaining elemental scandium in the arc tube after said substantially complete reaction.
Dependencies are inferred from the claim text.