The light source device and a filament

The present invention provides a light source device with high efficiency filament power conversion to visible light. Providing a filament disposed in the translucent airtight container, and a light source device having a light-transmitting airtight container for supplying the filament wire current. Filament comprising: a base formed of a high melting point metal material and a visible light reflectance in order to reduce visible light reflectance of the substrate to cover the film substrate is reduced. Thus, low reflectance of visible light, a high reflectance of infrared light, it is possible to suppress the radiation of infrared light, visible luminous efficiency improved.