| 摘要 |
A light source device comprising a filament showing high electric power-to-visible light conversion efficiency is provided. A light source device comprising a translucent gastight container, a filament disposed in the translucent gastight container, and a lead wire for supplying an electric current to the filament is provided. The filament comprises a substrate formed with a metal material and a white scatterer layer covering the substrate. To the white scatterer layer, a visible light-absorbing material that absorbs lights of visible region is added. The reflectance of the filament for visible lights is thereby made low, and the reflectance of the filament for infrared lights is thereby made high. Therefore, radiation of infrared lights is suppressed, and visible luminous efficiency can be enhanced. |
