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:
Apr. 17, 1984
Filed:
Mar. 23, 1981
R Calvin Owen, Jr, Lincoln, MA (US);
William T Plummer, Concord, MA (US);
Polaroid Corporation, Cambridge, MA (US);
Abstract
A zone focusing lens system is provided for use as a photographic camera objective. In the system, a fixed positive meniscus is placed ahead of the system aperture stop and is provided with an aspheric surface that is structured primarily to correct for off-axis aberrations. A lens disk having a plurality of different meniscus lens elements is located so that each of its elements can be selectively rotated into alignment proximate the system aperture stop to provide system focal lengths appropriate for sharply focusing objects located within different distance ranges. Each of the lens disk elements is provided with an aspheric surface that is structured primarily to reduce spherical aberrations.