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. 26, 1985
Filed:
May. 24, 1982
Hisao Fujita, Hachioji, JP;
Shozo Ishiyama, Hino, JP;
Konishiroku Photo Industry Co., Ltd., Tokyo, JP;
Abstract
The present invention relates to a zoom lens system having a new structure for use with still cameras, which is wide magnification-variable and compact whose zoom ratio is about three times. A positive third lens group of a conventional zoom lens comprising three lens group, i.e. positive, negative and positive is divided into two positive lens groups to thereby decrease the refractive power of each lens group and an airspace therebetween being increased and decreased, whereby enhancing the effect of magnification-variation or rendering it possible to be utilized for correction of aberration. Further, a positive lens group having a weak refractive power is arranged between image planes to effect correction of aberration. As a result, there is obtained a zoom lens system having a new arrangement of refractive power in order of positive, negative, positive, positive and positive.