| 摘要 |
PROBLEM TO BE SOLVED: To uniformize the intensity distribution of illumination light in an illumination area larger than an illumination device, in the illumination device and a biometric authentication device.SOLUTION: The illumination device includes a light source which is provided on the surface of a substrate and outputs light, and a diffraction optical element in which a plurality of diffraction gratings different in pitch and rotation direction are arranged and which diffracts the light, to irradiate the illumination area of an illumination object with the illumination light. The illumination area is formed so as to be larger than the occupancy areas of the diffraction optical element on a plane parallel to the surface of the substrate and the light source. |
