Patent ID: 8461754
Filing Date: 2013-06-11
Classification: H01K,Y02B

Abstract:
1. A glass halogen filament tube comprising a light-transmissive glass filament tube with a filament light source having a coil concentricity ratio of not greater than 20% disposed therein, the filament tube having a multi-layer optical interference coating deposited on the outer surface of the filament tube that transmits visible radiation at greater than 92% from about 400-750 nm and reflects infra-red radiation at greater than 80% from about 800-2500 nm back to the filament for re-absorption, the coated filament tube exhibiting an LPW gain of at least 26%; wherein the multi-layer optical interference coating comprises at least 210 layers; and wherein the multi-layer optical interference coating has a thickness of from about 3μ to about 25μ.