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:
Mar. 20, 1984
Filed:
Jul. 02, 1981
Nippon Kogaku K.K., Tokyo, JP;
Abstract
A zoom lens comprises a magnification changing system and a relay lens system succeeding the magnification changing system. The magnification changing system comprises, in succession from the object side, a first group as a focusing portion having a positive refractive power, a second group as a variator portion having a negative refractive power and movable along the optical axis to thereby change chiefly the focal length, and a third group as a compensator portion having a negative refractive power and maintaining the image plane fluctuated by movement of the variator portion at a predetermined position. The relay lens system comprises a fourth group as a forward relay system group having a positive refractive power and a fifth group as a rearward relay system group having a positive refractive power. The fourth group has three positive lens components of which at least the middle lens component is a cemented lens component having a convex cemented surface in the direction of the image side. The fifth group has at least one positive lens component which is a cemented lens having a convex cemented surface on the object side.