Patent ID: 7209295
Filing Date: 2007-04-24
Classification: G02B

Abstract:
1. An optical apparatus, comprising: a climbing type autofocusing function, an optical system, and an optical element having variable optical properties, which element changes from a first state to a fourth state, wherein: said optical element having variable optical properties changes from a second state to a third state for focusing, and to change from the first state to the second state and from the third state to the fourth state, said optical element having variable optical properties has an amount of change in its focal length required to change focus of said optical system by at least one-third of Sd determined by the following condition (370): where Sd is a focal depth of said optical system, Fno is an F-number of the optical system, k is a constant between 2 and 3, and P=√(Px·Py) wherein Px is a size in μm of one pixel of an image pickup device in an x-direction and Py is a size in μm of one pixel of the image pickup device in a y-direction.