IMAGE PROJECTION APPARATUS AND PLANETARIUM

摘要

Provided is an image projection apparatus 15 having a laser light source 6 and a diffractive optical element provided on a light path of laser light L from the laser light source 6, wherein a transparent member 17 having a higher refractive index than that of a region further forward from an emission surface is arranged on the light path of the laser light L, the diffractive optical element is formed on an emission surface 19 of the transparent member 17, and the laser light L is arranged so as to enter the diffractive optical element at an angle. Further, the diffractive optical element is formed so as to generate a diffraction image within a region which overlaps neither 0-order light LR of the laser light L nor a region occupied by a conjugate image, and is arranged in an orientation so as to irradiate a screen with diffraction light forming the diffraction image while substantially eliminating both the 0-order light and diffraction light constituting the conjugate image.