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. 05, 2002
Filed:
Jun. 21, 2000
Shinsuke Shikama, Tokyo, JP;
Mistubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A retrofocus lens system comprises a first lens group having a negative power, a second lens group having a positive power, and a third lens group having a positive power. The first lens group includes a first lens, a meniscus-shaped second lens having a negative power and a convex surface facing the large conjugate side, a third lens having a negative power, and a fourth lens. The second lens group includes a fifth lens having a positive power. The third lens group includes a sixth lens having a negative power, both surfaces of which are concave, a seventh lens having a positive power, both surfaces of which are convex, an eighth lens having a positive power, both surfaces of which are convex, and a ninth lens having a positive axial power. The system satisfies 0.9<f /f <1.8, 1.5<|f |/f<2.7, |f |/f>30, and f /f>6, where f is a focal distance of the whole lens system, |f | is an absolute value of a focal distance of the first lens group, f is a focal distance of the second lens group, f is a focal distance of the third lens group, |f | is an absolute value of a focal distance of the first lens, and f is an axial focal distance of the ninth lens.