Higher efficiency incandescent lighting units

摘要

An improved high efficiency general service incandescent lighting unit is disclosed. The lamp has coaxial outer and inner envelopes. The inner envelope has a low voltage filament coaxially disposed therein, a halogen gas atmosphere and a fill-gas at a high pressure. The outer envelope has a coating of a light transmissive reflective infrared film on its inner surface. Further disclosed are various control systems for reducing a typical 120 v. A.C. voltage and applying the reduced A.C. or D.C. voltage across the low voltage filament within the inner envelope.