PROBLEM TO BE SOLVED: To provide a light source device that emits diffused illumination light and illumination light with reduced diffusion.SOLUTION: A light source device comprises: a light source for emitting primary light a light guide member for guiding the primary light a primary illumination unit including an incident surface and an emission surface and having a diffusion member that converts light distribution characteristics of the primary light having entered from the light guide member so as to emit as secondary light and an adaptor having an adaptor incidence side opening for allowing incidence of the secondary light, a light conversion member for converting optical characteristics of the secondary light so as to emit as illumination light and an adaptor emission side opening for emitting illumination light obtained by the conversion in the light conversion member, the adaptor being attached/detached to/from the primary illumination unit. A diffusion function cancellation part is provided between the emission surface of the diffusion member and the optical conversion member with the adaptor being fitted to the primary illumination unit so that a function to convert light distribution characteristics of the diffusion member is reduced and a spread angle of the secondary light emitted from the primary illumination unit is made smaller when the adaptor is fitted than when the adaptor is not fitted.COPYRIGHT: (C)2014,JPO&INPIT【課題】拡散する照明光、及び拡散が低減された照明光を射出する光源装置を提供する。【解決手段】1次光を出射する光源と、1次光を導光する導光部材と、入射面と射出面とを備え、導光部材から入射された1次光の配光特性を変換し2次光として射出する拡散部材を有する1次照明ユニットと、2次光が入射するアダプタ入射側開口と、2次光の光学特性を変換し照明光として射出する光変換部材と、光変換部材で変換された照明光を射出するアダプタ射出側開口とを有し、1次照明ユニットに着脱されるアダプタと、を具備する光源装置であり、アダプタを1次照明ユニットに装着したときの拡散部材の射出面と光変換部材との間に、拡散部材の配光特性を変換する機能を低下させ、1次照明ユニットから射出される2次光の広がり角がアダプタ装着時にアダプタ未装着時よりも小さな広がり角となるように変化させる拡散機能打消し部が設けられている。【選択図】図1
