Wide-angle lens,申请号US19940275417-传众专利搜索

Wide-angle lens

申请公布号：US5631780(A)

申请号：US19940275417

申请日期：1994.07.15

申请公布日期：1997.05.20

申请人：

NIKON CORPORATION

发明人：SATO, HARUO

分类号：G02B13/04;G02B13/06;G02B13/18;(IPC1-7):G02B13/04

主分类号：G02B13/04

摘要：A retrofocus type wide-angle lens for achieving a highly stable imaging performance and a reduction in spherical aberrations, astigmatism, and coma, while allowing for a large aperture and a large wide angle of view. The retrofocus type wide-angle lens has, in the following order from an object side, a first lens group having a negative refracting power and being fixed in a focusing operation and a second lens group having a positive refracting power and being moved in the focusing operation. The first lens group has, in the following order from the object side, a first unit with a negative refracting power and a second unit having a positive refracting power. The second lens group has, in the following order from the object side, a first unit with a negative refracting power, a second unit with a positive refracting power, a third unit with a negative refracting power and a fourth unit with a positive refracting power. The third unit of the second lens group having a cemented lens formed of a lens with a negative refracting power and a lens with a positive refracting power, the cemented lens constituting a negative meniscus lens with a convex surface directed to an image side.