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:
Aug. 27, 2002
Filed:
Jul. 07, 2000
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A zoom lens comprising, in the order of an increasing distance from an object; a fixed first lens group ( ) having a positive refractive power; a second lens group ( ) containing an aspherical surface, having a negative refractive power and being in charge of a variable power action by being moved; a fixed third lens group ( ) containing an aspherical surface and having a positive refractive power; and a fourth lens group ( ) containing an aspherical surface, having a positive refractive power and moving while following up a moving object point; wherein the surface on the image plane side of a lens positioned closest to the image plane in the third lens group ( ) has a concave plane having a strong refractive power with respect to the image plane and a relation, 2.0<L/CL <2.3, is satisfied when an effective aperture of a lens ( ) positioned closest to the object in the first group is CL and a distance from the lens ( ) to the image plane is L, whereby a high magnification, compact and wide-angle zoom lens having its aberration adequately corrected can be obtained with a simple configuration.