ILLUMINATION DEVICE, PROJECTION-TYPE IMAGE DISPLAY DEVICE, AND OPTICAL DEVICE

摘要

[Problem] To provide an illumination device and a projection-type image display device that uniformly illuminate an illuminated area (image-forming area) without noticeable speckle noise. [Solution] This illumination device is characterized by being provided with: a light source (11) that projects coherent light; a light scanning part (15) that scans the coherent light projected from the light source (11); and an optical path conversion system (21) that is set up in such a manner that the coherent light scanned by the light scanning part (15) illuminates the illuminated area so as to overlap over time. The illumination device is further characterized in that the angle of incidence of the coherent light that is incident upon each point of the illuminated area changes over time.