Patent ID: 8529070

Claim:
A projection optical apparatus comprising: a spatial light modulator; and a projection optical system including a first optical system having a transmissive-refractive element and a second optical system having a reflective-refractive element, wherein an image formed by the spatial light modulator is projected by the projection optical system on a projection surface, wherein a light beam that travels along an optical path that leads from the second optical system to the projection surface in an optical path between a center of the image formed by the spatial light modulator and the projection surface is projected at an angle with respect to a normal to the projection surface, wherein, when a vector in the direction of travel of the light beam is vector A, a projected component of the vector A that is substantially parallel to the projection surface is defined as an up direction, and a direction opposite to the up direction is defined as a down direction, and wherein an optical axis of the first optical system is folded to a folded position by an optical path deflecting unit in a direction including a vector in an up or down direction in an area of the first optical system where the light beam entering, the optical path deflecting unit is a converging light beam or a substantially parallel light beam.