Patent ID: 8175687

Claim:
A light source device for fluorescence diagnosis and photodynamic therapy comprising: a light source comprised of an excitation light source emitting light in a short wavelength range and a long wavelength light source emitting light in a long wavelength range, wherein said short wavelength range is different from said long wavelength range; a light guide adapted to guide light to a diagnostic region; a light path coupler coupling light emitted from the light source to an incident end of said light guide; a first filter for selectively transmitting emitted light based on wavelength; a second filter for photodynamic therapy positionable in a light path between the light path coupler and the light guide; and a switching device which controls emissions of the long wavelength light source so as to achieve any of (i) a white light condition where both said excitation light and said long wavelength light are directed to said diagnostic region, (ii) an excitation condition where only said excitation light is directed to said diagnostic region, and (iii) a photodynamic condition where both said excitation and said long wavelength light are directed to said diagnostic region under a photodynamic therapy condition.