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:
Dec. 17, 1991
Filed:
Aug. 27, 1990
Elliot M Burke, Santa Barbara, CA (US);
Medical Concepts, Inc., Goleta, CA (US);
Abstract
A lens system is characterized by a back focal length that substantially exceeds its front focal length. An input lens having a relatively short focal length is arranged to receive an image. The back of the input lens is a mirrored concave surface that is inclined in such a way as to direct the reflected image to a concave mirror. The concave mirror and a Mangin mirror having a convex mirrored back surface form a relay lens system for redirecting the image reflected from the concave mirror to a second point on that mirror from which the image is reflected to a predetermined focal point. The Mangin mirror is arranged to remove chromatic and spherical aberrations from the virtual image. The lenses and mirrors of the system are arranged so that the optical distance from the concave mirror to the predetermined focus is at least three times the focal length of the first lens.