Importance

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Abstract

An object of this invention is to provide an incandescent bulb which has sufficiently high brightness and produces a god light distribution on a surface irradiated by the light, and a light source apparatus having high usage efficiency of the light radiated from the incandescent light bulb. The incandescent light bulb is provided therein with a filament that includes a plurality of filament segments made from a single coil formed by winding one wire material that respectively extend along an axial direction of the bulb and are arranged in parallel to form a flat surface, wherein a pitch of the plurality of filament segments located at a central part of the bulb is smaller than a pitch of a plurality of filament segments located at both side portions.

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First Claim