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ENDOSCOPE AND OBJECTIVE LENS FOR THE SAME

  • US 20110002052A1
  • Filed: 07/06/2010
  • Published: 01/06/2011
  • Est. Priority Date: 07/06/2009
  • Status: Active Grant
First Claim
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1. An objective lens for an endoscope, comprising:

  • a front lens group having a negative power; and

    a rear lens group having a positive power arranged such that an aperture stop is positioned between the front lens group and the rear lens group,wherein;

    the front lens group comprises at least a front-side negative lens and a front-side positive lens arranged in this order from an object side;

    the rear lens group comprises at least a rear-side positive lens and a cemented lens arranged in this order from the object side, the cemented lens being configured by cementing together a negative lens and a positive lens; and

    the objective lens satisfies following conditions;




    4.5≦

    fF/f≦



    2.0  



    (1); and


    1.5≦

    fRP/f≦

    2.5  



    (2)where fF (unit;

    mm) represents a focal length of the front lens group, f (unit;

    mm) represents a total focal length of the front lens group and the rear lens group, and fRP (unit;

    mm) represents a focal length of the rear-side positive lens.

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