Patent ID: 10845020

Abstract:
To protect observer's eyes while forming a clear illumination pattern on a desired region to be illuminated. An illumination device includes a light source that emits coherent light, a collimating optical system that enlarges and collimates a beam diameter of the coherent light emitted from the light source, and a diffractive optical element that diffracts the coherent light collimated by the collimating optical system into a predetermined diffusion angle space. The diffractive optical element has a plurality of element diffractive optical portions and has a function to illuminate the region to be illuminated defined at a predetermined position and having predetermined size and shape to form the desired illumination pattern. Each of the plurality of element diffractive optical portions has a function to illuminate at least a part of the region to be illuminated, and diffractive characteristics of the element diffractive optical portions are different from each other.