Ir-Reflecting Multilayer Films For Energy-Efficient Lamps

Most of the radiated energy of incandescent or halogen lamps is emitted in the near-infrared rather than in the visible. This makes these lamps inherently inefficient. Numerous improvements in efficiency by means of thin films have been described in patents and scientific papers over the last four decades. The most effective approach is an interference heat reflector that comprises at least 30 layers and transmits nearly 100% of the visible light while reflecting up to 80% of the radiation in the wavelength region between 750 and 1800nm back to the filament. The reflected IR energy is abosrbed by the filament, heats the filament up and in this way reduces the power consumption of the lamp.