Patent ID: 8740406

Claim:
A light source device comprising: a first excitation light source generating a first excitation light; a second excitation light source generating a second excitation light, wherein a peak wavelength of the second excitation light is shorter than a peak wavelength of the first excitation light; a filter, which substantially transmits the first excitation light at input angles smaller than a first threshold angle and substantially reflects the first excitation light at input angles greater than a second threshold angle, and which substantially transmits the second excitation light at input angles smaller than a third threshold angle, wherein the third and second threshold angles are greater than the first threshold angle; wherein the first excitation light source is arranged to input the first excitation light onto the filter at input angles smaller than the first threshold angle and passes through the filter, and the second excitation light source is arranged to input the second excitation light onto the filter at input angles smaller than a third threshold angle and at least partially greater than the first threshold angle and passes through the filter; and a wavelength conversion device carrying a wavelength conversion material, disposed to receive the first and second excitation lights that have passed through the filter, the wavelength conversion material converting a part of the first and second excitation lights into a converted light and reflecting another part of the first and second excitation lights toward the filter; and wherein the filter reflects a part of the first excitation light that has been reflected from the wavelength conversion material, and which reaches the filter at input angles greater than the second threshold angle, back toward the wavelength conversion material.