The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 25, 2008
Filed:
May. 22, 2007
Azusa Noguchi, Hino, JP;
Hisashi Goto, Tokyo-to, JP;
Azusa Noguchi, Hino, JP;
Hisashi Goto, Tokyo-to, JP;
Olympus Corporation, Tokyo, JP;
Abstract
A zoom optical system includes, in order from the object side, a first lens unit with positive refracting power, a second lens unit with negative refracting power, a third lens unit with positive refracting power, and a fourth lens unit with positive refracting power. An aperture stop is interposed between the second lens unit and the fourth lens unit. Upon zooming, at least, the first lens unit, the second lens unit, and the third lens unit are moved so that spacings between these lens units are varied. The first lens unit is constructed with at most two lens elements. The second lens unit includes, in order from the object side, a first negative lens in which the image-side surface is greater in curvature than the object-side surface, an air spacing, a second negative lens in which the image-side surface is greater in curvature than the object-side surface, an air spacing, and a positive lens in which the object-side surface is greater in curvature than the image-side surface. The second negative lens is constructed to satisfy the following condition:−0.7<23<0.05where r23 is the radius of curvature of the object-side surface of the second negative lens and fis the focal length of the second lens unit.