Patent Number: 6,295,155

Title: Spatial frequency converting device and optical system having the same

Abstract: A spatial frequency converting device in which the amount of conversion of spatial frequency characteristics is variable. An optical system using the spatial frequency converting device is a variable-focus optical system in which the depth of field can be enlarged by fixed signal processing. A pupil modulation element provided in a fixed-focus optical system includes a plurality of elements. At least one of the elements is rotated about an optical axis. In the variable-focus optical system, a movable lens placed on the object side of a pupil modulation element is moved along an optical axis.

Inventors: Suga; Takeshi (Hachioji, JP)

Assignee: Olympus Optical Co., Ltd.

International Classification: G02B 27/46 (20060101); G02B 026/00 ()

Expiration Date: 09/25/2018