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:
Oct. 02, 2012
Filed:
Oct. 27, 2010
Kazuhiro Oe, Suwa, JP;
Kazuhiro Oe, Suwa, JP;
Nittoh Kogaku K.K., Nagano, JP;
Abstract
A lens system includes, in order from an object side, a first lens group with positive refractive power, a second lens group with negative refractive power that moves during zooming, a third lens group with positive refractive power, and a fourth lens group with positive refractive power that moves during zooming and focusing adjustments. The first lens group includes a lens with positive refractive power and an Abbe number vdthat satisfies a following condition (vd>80). The second lens group includes a lens with positive refractive power and an Abbe number vdand two lenses with negative refractive power and Abbe numbers vdand vdrespectively, the Abbe numbers Vd, Vdand Vdsatisfying following conditions (vd, vd, vd<23). The third lens group includes a plurality of lenses with positive refractive power, an average vdof the Abbe numbers of the plurality of lenses with positive refractive power satisfies a following condition (77.5<vd<82.5), and a sum ndts of thermo-optical coefficients of the plurality of lenses with positive refractive power in a temperature range of 40° C. to 60° C. satisfies a following condition (−12.8×10<ndts<−2.4×10).