Fast aspherical lens system,申请号US19940260829-传众专利搜索

Fast aspherical lens system

申请公布号：US5513045(A)

申请号：US19940260829

申请日期：1994.06.16

申请公布日期：1996.04.30

申请人：

ASAHI KOGAKU KOGYO KABUSHIKI KAISHA

发明人：ITO, TAKAYUKI;SUGANO, YASUYUKI

分类号：G02B13/04;G02B13/18;(IPC1-7):G02B13/04

主分类号：G02B13/04

摘要：A fast aspherical lens system is provided which includes a front lens group having a negative power, a diaphragm, and a rear lens group having a positive power, arranged in this order from the side of an object to be photographed. The rear lens group is provided with at least one lens having a diverging aspherical surface and satisfies the following conditions: -0.6<f/fF,<-0.2;tm (1) 3.0< SIGMA dF+S/f<8.0;(2) 3.0< SIGMA dR/f<6.0;(3) -0.9< DELTA IASP<-0.1;(4) where f represents a focal length of the entire lens system, fF represents a focal length of the front lens group, SIGMA dF+S represents a sum of the thickness of the front lens group and a distance between the front lens group and the rear lens group, and SIGMA dr represents a thickness of the rear lens group, and DELTA IASP represents an aberration factor of the aspherical surface term of the third-order spherical aberration factor of the aspherical lens.