Patent ID: 8848267

Claim:
An illumination apparatus using a coherent light source, comprising: a coherent light source ( 50 ) that generates a coherent light beam (L 50 ); a hologram recording medium ( 45 , 46 , 85 ) on which an image ( 35 ) of a scatter plate ( 30 ) is recorded; and a light beam scanning device ( 60 , 65 ) that irradiates the light beam (L 60 , L 65 ) onto the hologram recording medium ( 45 , 46 , 85 ), and scans the light beam (L 60 , L 65 ) so that an irradiation position of the light beam (L 60 , L 65 ) on the hologram recording medium ( 45 , 46 , 85 ) changes with time, wherein the image of the scatter plate ( 30 ) is recorded as a hologram on the hologram recording medium ( 45 , 46 , 85 ) as a form of interference fringes which reproduce the image of the scatter plate ( 30 ) when respective light beams (L 61 , L 62 ) are given as illumination light advancing toward respective one points (P 1 , P 2 ) within the medium along respective particular optical paths so that reproduction images ( 35 ) are identical to each other and produced at a same position, the coherent light source ( 50 ) generates a light beam (L 50 ) with a wavelength capable of reproducing the image ( 35 ) of the scatter plate, the light beam scanning device ( 60 , 65 ) scans the generated light beam (L 60 , L 65 ) so that an irradiation direction of the generated light beam (L 60 , L 65 ) with respect to the hologram recording medium ( 45 , 46 , 85 ) is along one of said particular the optical paths, and reproduction light of the image ( 35 ) of the scatter plate ( 30 ) obtained from the hologram recording medium ( 45 , 46 , 85 ) is used as illumination light.