Variable-magnification image-forming optical system
AssigneeOlympus Optical Co., Ltd.
InventorTakayoshi Togino
Life of this patent
Estimating the term…
Abstract
A variable-magnification image-forming optical system having at least four lens units including a decentered optical system. The decentered optical system has at least one curved surface with a rotationally asymmetric surface configuration having no axis of rotational symmetry in nor out of the surface. Rotationally asymmetric aberrations due to decentration are corrected by the rotationally asymmetric surface configuration. A magnification change is effected by changing at least one of the spacings between the four lens units.
Claims50
A variable-magnification image-forming optical system comprising a first lens unit having at least one lens;
- a second lens unit disposed on an image side of said first lens unit;
- a third lens unit disposed on an image side of said second lens unit;
- and a fourth lens unit disposed on an image side of said third lens unit,
- wherein when zooming from a wide-angle end of said optical system to a telephoto end of said optical system is performed, a spacing between said first lens unit and said second lens unit and a spacing between said second lens unit and said third lens unit are varied, and
- wherein said fourth lens unit includes a decentered optical system having at least one curved reflecting surface and a non-rotationally symmetric curved surface operating to correct non-rotationally symmetric aberrations produced by a decentering action of said curved reflecting surface.
Dependencies are inferred from the claim text.