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. 01, 1988
Filed:
Oct. 20, 1987
Toshiro Ozawa, Kawasaki, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
An ultra compact zoom lens system includes: a first lens unit having a positive refracting power and including a positive lens, a negative lens and a cemented lens comprised of a negative lens and a positive lens; a second lens unit having a negative refracting power and including a positive lens and a negative lens; and a third lens unit having a positive refractive power and including a positive lens. The second lens unit has a paraxial lateral magification which is always larger than unity and the third lens unit is fixed in position. And, the focal distance of the entire system is varied by varying a spacing between the first and second lens units and a spacing between the second and third lens units relative to each other. Selected parameters, such as focal distance, refractive index and dispersion, of selected lenses defining the present zoom lens system should have values within predetermined ranges so as to provide an ultra compact zoom lens system which provides an excellent image forming characteristic over the entire zooming range and which has a large zoom ratio.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile