Spatial frequency converting device and optical system having the same
AssigneeOlympus Optical Co., Ltd.
InventorTakeshi Suga
Life of this patent
Estimating the term…
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.
Claims10
A spatial frequency converting device constructed and arranged to convert spatial frequency characteristics of an optical system, comprising a plurality of converting units, said spatial frequency converting device being selectively actuatable to switch between a state of performing spatial frequency characteristic conversion and a state of not performing spatial frequency characteristic conversion, said plurality of converting units including two converting units, said two converting units being provided in symmetry with respect to an aperture stop,
- wherein said state of performing spatial frequency characteristic conversion and said state of not performing spatial frequency characteristic conversion are switched from one to the other by rotating at least one of said plurality of converting units about an optical axis.
An optical system comprising a spatial frequency converting unit constructed and arranged to convert spatial frequency characteristics of said optical system, said optical system being a variable-focus optical system having an aperture stop of a fixed size,
- wherein an F-number is invariable regardless of a change in a focal length.
A spatial frequency converting device for converting spatial frequency characteristics of an optical system,
- said spatial frequency converting device comprising a plurality of converting units,
- said plurality of converting units being provided in symmetry with respect to an aperture stop of said optical system,
- wherein an amount of conversion of spatial frequency characteristics is variable by rotating at least one of said plurality of converting units about an optical axis.
Dependencies are inferred from the claim text.