Patent ID: 7605775

Claim:
A displaying optical system, comprising: a scanning member for deflecting a light emitted from a light source; a scanned surface on which an image is formed by scanning with the light deflected by the scanning member, the scanned surface being a reflection surface; an optical surface provided at a position common to a first optical path through which a light reflected by the scanned surface travels and a second optical path through which a light from the scanning member to the scanned surface travels, the optical surface, in accordance with a polarization direction, transmitting the light traveling through one of the first optical path and the second optical path and reflecting the light traveling through the other optical path, the optical surface having a rotational asymmetry shape; and a phase plate that emits a light which has been incident into the phase plate by changing a state of polarization of the incident light, the phase plate being provided at the position common to the first optical path and the second optical path.