发明授权
US06239921B1 Taking lens system 有权
拍摄镜头系统

  • 专利标题: Taking lens system
  • 专利标题(中): 拍摄镜头系统
  • 申请号: US09457747
    申请日: 1999-12-10
  • 公开(公告)号: US06239921B1
    公开(公告)日: 2001-05-29
  • 发明人: Masashi Isono
  • 申请人: Masashi Isono
  • 优先权: JP10-353181 19981211; JP10-353431 19981211
  • 主分类号: G02B1318
  • IPC分类号: G02B1318
Taking lens system
摘要:
A taking lens system has, from the object side, a front lens unit, an aperture stop, and a rear lens unit. The front lens unit is composed of two lens elements that are, from the object side, a positive glass element and a negative plastic lens element. The rear lens unit has a positive plastic lens element disposed at the image-side end thereof. On the object side of this positive plastic lens element is disposed solely a lens element made of glass. The following condition is fulfilled: |f×fa/Ha2+f×fb/Hb2|≦300 where f represents the focal length of the entire taking lens system; fa represents the focal length of the negative plastic lens element of the front lens unit; fb represents the focal length of the positive plastic lens element of the rear lens unit; Ha represents the height of incidence at which an axial F-number ray enters the negative plastic lens element of the front lens unit; and Hb represents the height of incidence at which an axial F-number ray enters the positive plastic lens element of the rear lens unit.
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