Incandescent lamp with bulb having IR reflecting film

摘要

This invention relates to an incandescent lamp bulb comprising a visible light transmitting and infrared ray reflecting film formed on at least either one of the inside and outside of a tubular, transparent bulb, said film being composed of a lamination of alternate high and low refractive index layers, wherein the optical film thickness of any one of the high reflective index layers ranges from 0.21 to 0.31, that of the topmost low refractive index layer ranges from 1/20.21 to 1/2. times.0.31, that of at least one low refractive index layer ranges from 20.21 to 20.31, and that of any remainder low refractive index layer ranges from 0.21 to 0.31.