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, 1980
Filed:
Jul. 17, 1978
Edward K Kaprelian, Mendham, NJ (US);
Questar Corporation, New Hope, PA (US);
Abstract
The invention provides a highly corrected, parfocalized, two-focal-length optical system comprising a primary image producing group consisting of a catadioptric lens system which forms its image within a first, positive field lens, and a second group comprising a symmetrical relay system coaxial with the primary group and movable axially relative to the primary image producing group, the relay system reimaging the image formed by the primary group through a second, negative field lens onto the fixed plane of the final image, movement of the relay lens between its extreme positions permitting close focusing of the entire system without altering its overall length.