Light source device, lighting device, vehicular headlight, and vehicle

Abstract

A headlight system in accordance with the present invention includes: a semiconductor laser element that emits laser light; a light-emitting section that upon receipt of the laser light emitted from the semiconductor laser element, emits illumination light which is both the laser light and fluorescence obtained by wavelength conversion of a portion of the laser light; and a diffusion plate that mixes the laser light and fluorescence which are contained in the illumination light emitted by the light-emitting section.

1 . (canceled) 
     
     
         2 . A light source device comprising:
 an excitation light source that emits excitation light;   a light-emitting section that, upon receipt of excitation light emitted from the excitation light source, emits illumination light which is both the excitation light and wavelength-converted light obtained by wavelength conversion of a portion of the excitation light; and   a light projection section which projects the illumination light, the excitation light being laser light, and the excitation light source being a semiconductor laser element,   the light projection section being a lens, and   the lens being placed to abut, at a surface thereof facing the light-emitting section, a diffusion plate having asperities.   
     
     
         3 . The light source device according to  claim 1 , wherein the diffusion plate and the lens are formed integrally. 
     
     
         4 . The light source device according to  claim 2 , wherein the diffusion plate is such that a maximum full width at half maximum of intensity distribution of outgoing light derived from incoming parallel light is not less than O.7 degree and not more than 3.0 degree. 
     
     
         5 . The light source device according to  claim 2 , wherein the diffusion plate has a micro lens array pattern or surface relief holographic pattern formed thereon. 
     
     
         6 . A lighting device comprising a light source device which includes:
 an excitation light source that emits excitation light;   a light-emitting section that, upon receipt of excitation light emitted from the excitation light source, emits illumination light which is both the excitation light and wavelength-converted light obtained by wavelength conversion of a portion of the excitation light; and   a light projection section which projects the illumination light,   the excitation light being laser light, and the excitation light source being a semiconductor laser element,   the light projection section being a lens, and   the lens being placed to abut, at a surface thereof facing the light-emitting section, a diffusion plate having asperities.   
     
     
         7 . A vehicular headlight comprising a light source device which includes:
 an excitation light source that emits excitation light;   a light-emitting section that, upon receipt of excitation light emitted from the excitation light source, emits illumination light which is both the excitation light and wavelength-converted light obtained by wavelength conversion of a portion of the excitation light; and   a light projection section which projects the illumination light,   the excitation light being laser light, and the excitation light source being a semiconductor laser element,   the light projection section being a lens, and   the lens being placed to abut, at a surface thereof facing the light-emitting section, a diffusion plate having asperities.   
     
     
         8 . A vehicle comprising a light source device which includes:
 an excitation light source that emits excitation light;   a light-emitting section that, upon receipt of excitation light emitted from the excitation light source, emits illumination light which is both the excitation light and wavelength-converted light obtained by wavelength conversion of a portion of the excitation light; and   a light projection section which projects the illumination light,   the excitation light being laser light, and the excitation light source being a semiconductor laser element,   the light projection section being a lens, and   the lens being placed to abut, at a surface thereof facing the light-emitting section, a diffusion plate having asperities.