INCANDESCENT LAMP WITH INFRARED RAY REFLECTING FILM

摘要

PROBLEM TO BE SOLVED: To expand the wavelength band when reflecting infrared rays, to increase the heat quantity fed back to a filament and to increase the light quantity by setting the film thickness of at least one layer of low-refraction factor films in an infrared ray reflecting film to a specific range. ;SOLUTION: An infrared ray reflecting film 3 is laminated with low-refraction factor films made of SiO2 (refraction factor = 1.46) and high-refraction factor films made of TiO2 (refraction factor = 2.1) in turn, for example. A high- refraction factor film with the film thickness of 1/4-wavelength (e.g. 260 nm) is provided on the outer surface of a bulb 2 as a first layer, a low-refraction factor film with the film thickness of 1/4-wavelength is provided as a second layer, and the high-refraction factor films and the low-refraction factor films are laminated in turn in 18 layers. The low-refraction factor film of the fourth layer and the low-refraction factor film of the eighth layer have the film thickness of 1/2-wavelength (520 nm). The infrared ray reflection band is expanded by about 400 nm, and the efficiency of an electric lamp 1 can be improved.;COPYRIGHT: (C)2000,JPO