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US 4,375,605 AGranted
Ellipsoidal envelope for incandescent lamp with infrared energy return means
AssigneeDuro-Test Corporation
InventorsRaymond P. Fontana, Peter Walsh
Life of this patent
Estimating the term…
Abstract
An incandescent electric lamp having a coating to reflect infrared energy back to the filament to raise its operating temperature in which the envelope is shaped as an ellipsoid and the filament and envelope have a relationship to reduce losses due to aberration and to produce a more uniform temperature distribution along the filament.
Claims9
An incandescent electric lamp comprising:
- an ellipsoidal shaped envelope having a base portion, said envelope defining a major axis on which is a pair of spaced focal points,
- an incandescent filament mounted within said envelope,
- means for supplying electrical energy to said filament to cause it to incandesce to produce energy in both the infrared and the visible range,
- means for cooperating with said envelope to return to the filament a substantial portion of the infrared energy produced by said filament and for transmitting therethrough a substantial portion of the visible range energy produced by said filament;
- said filament being elongated, generally cylindrical and linear along its major axis, at least as long as the distance between the two foci of the major axis of the envelope, and being mounted along the major axis of the ellipsoidal envelope so that the two foci of the ellipsoid are located on the filament a spaced points therealong.
2 more elements
Dependencies are inferred from the claim text.