Patent ID: 8029146

Claim:
A light source device which produces illumination light for illuminating a target illumination area on a predetermined light receiving surface, comprising: a light source which emits light; a superimposing illumination element which superimposes the light emitted from the light source and produces an illumination light for illuminating the target illumination area; a plurality of optical path converting units including a first optical path converting unit and a second optical path converting unit disposed on an optical path between the light source and the superimposing illumination element to convert the optical path of the light emitted from the light source and to supply the light having the converted optical path to the superimposing illumination element; and a shift unit which shifts the plurality of optical path converting units such that the center axis of light released from the plurality of optical path converting units is moved by parallel displacement, wherein: the first optical path converting unit is a reflection member which reflects the light emitted from the light source toward the second optical path converting unit; the second optical path converting unit is a reflection member which reflects a light reflected by the first optical path converting unit toward the superimposing illumination element; the shift unit continuously reciprocates the first optical path converting unit and the second optical path converting unit; the shift unit always shifts at least one of the plurality of optical path converting units; and the shift unit shifts the first optical path converting unit at a time when the second optical path converting unit reaches a returning point during reciprocating movement.