Image-forming optical apparatus having a decentered optical surface

摘要

A compact image-forming optical apparatus which is free from moire fringes and capable of providing an aberration-free, clear image of minimal distortion even at a wide field angle. The image-forming optical apparatus has an objective optical system (104) and an electronic image pickup device (108). The objective optical system (104) has at least one reflecting surface (106, 107) decentered such that the whole surface is tilted with respect to the axial principal ray. The reflecting surface has a rotationally asymmetric surface configuration that corrects rotationally asymmetric decentration aberrations caused by decentration. A low-pass member (103) is disposed in the vicinity of a pupil plane (101) closer to the object than the reflecting surface. The low-pass member cuts off a high-frequency component concerning the object image in a bundle of rays led to the electronic image pickup device (108).