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:
Feb. 08, 1994
Filed:
Apr. 10, 1992
Applicant:
Inventor:
Yuichiro Kanoshima, Yokohama, JP;
Assignee:
Ricoh Company, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B / ; G02B / ;
U.S. Cl.
CPC ...
359740 ; 359760 ; 359775 ;
Abstract
A scanner lens for reading has first to fourth lens groups sequentially arranged from an object side to an image side. The first to fourth lens groups are constructed by six lenses. Each of the six lenses is constructed by a positive or negative meniscus lens having a convex or concave face directed on the object side. The scanner lens further has a diaphragm arranged between the second and third lens groups. Refractive indices N.sub.g, N.sub.F, N.sub.d and N.sub.C at respective wavelengths on lines g, F, d and C, an Abbe's number .nu. on line d, and a partial dispersion ratio .theta.=(N.sub.g -N.sub.d)/(N.sub.F -N.sub.C) satisfy the following condition,