| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an imaging optical system capable of satisfactorily correcting any trapezoid distortion of an object image (imaged object image) in spite of a compact configuration. <P>SOLUTION: In an imaging optical system TL for use in an image pickup device that picks up an image of an object with an image pickup element IS in a direction oblique to the surface of the object, the imaging optical system TL comprises a rotational symmetric lens group G1 comprising a plurality of rotational symmetric lenses L11 to L14 sequentially arrayed along an optical axis from the image pickup element IS side onward and formed in rotational symmetry with respect to a central axis, a free-form surface lens group G2 comprising a plurality of free-form surface lenses L21 to L23 formed in rotational asymmetry with respect to the central axis, and a free-form surface mirror M having a reflective face formed in rotational asymmetry with respect to the central axis. <P>COPYRIGHT: (C)2012,JPO&INPIT |
