Patent ID: 7301684

Claim:
A scanning optical system comprising: a scanning device which scans light from a light source, and a first optical system which directs the light scanned by the scanning device to an exit pupil, wherein the first optical system comprises a first surface and a second surface, the first surface having at least a reflective action and being decentered with respect to a central principal ray, the second surface reflecting light reflected by the first surface toward the first surface, wherein the first surface reflects the central principal ray, which has again been made incident to the first surface from the second surface, toward a side substantially opposite to a side toward which the central principal ray was reflected the last time with respect to a normal on a hit point of the central principal ray on the first surface, and wherein the first optical system makes the light from the scanning device form an intermediate image, and a diffuse-reflective surface serving as the second surface is disposed at one of the positions of the intermediate image and in the vicinity of the intermediate image.