OPTICAL FILTER, PRODUCTION METHOD FOR THIS OPTICAL FILTER AND OPTICAL DEVICE USING THIS OPTICAL FILTER AND HOUSING STRUCTURE FOR THIS OPTICAL FILTER

摘要

An optical low-pass filter (10) comprising, laminated sequentially, a crystal double-refraction plate (11), a 1/4 wavelength plate (12) and a crystal double-refraction plate (13). Curvature chamfering portions (13a, 13b) are formed around the light outgoing chambering (principal plane) of the crystal double-refraction plate (13). A curvature chamfering width is smaller on the principal plane side (t2) than on the side plane side (t1).