Patent ID: 8149477
Filing Date: 2012-04-03
Classification: G02B

Abstract:
1. An optical scanning apparatus comprising: a light emitting unit; a deflecting unit having a deflecting surface; an incidence optical system configured to cause a light beam emitted from the light emitting unit incident on the deflecting unit; an imaging optical system including a transmissive imaging optical element that forms an image of a light beam on a surface to be scanned, the light beam being subjected to scanning and deflected by the deflecting surface of the deflecting unit, with the transmissive imaging optical element having a first transmitting surface, a second transmitting surface, a third transmitting surface, and a fourth transmitting surface; and a reflective optical element disposed in an optical path between the deflecting unit and the transmissive imaging optical element, the reflective optical element having a reflecting surface, wherein, after the light beam subjected to scanning and deflected by the deflecting surface of the deflecting unit passes through the transmissive imaging optical element in order of the first transmitting surface and the second transmitting surface and then reflected at the reflecting surface of the reflective optical element, the light beam re-passes through the transmissive imaging optical element in order of the third transmitting surface and the fourth transmitting surface, and wherein the following condition is satisfied:  where L