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OBJECTIVE LENS FOR ENDOSCOPES AND ENDOSCOPE

  • US 20170224201A1
  • Filed: 12/27/2016
  • Published: 08/10/2017
  • Est. Priority Date: 02/08/2016
  • Status: Active Grant
First Claim
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1. An objective lens for endoscopes comprising, in order from the object side to the image side:

  • a single lens having a negative refractive power and a concave surface toward the object side;

    an aperture stop; and

    a cemented lens;

    the cemented lens being formed by one positive lens and one negative lens which are cemented together;

    the number of lenses within the entire system being only three; and

    Conditional Formulae (1) and (2) below being satisfied;


    0.1<

    dSt/Lt<

    0.6  



    (1)
    0<

    vp−

    vn<

    55  



    (2)wherein dSt is the distance along the optical axis from the surface toward the object side of the single lens to the aperture stop, Lt is the distance along the optical axis from the surface toward the object side of the single lens to the surface toward the image side of the cemented lens, vp is the Abbe'"'"'s number with respect to the d line of the positive lens within the cemented lens, and vn is the Abbe'"'"'s number with respect to the d line of the negative lens within the cemented lens.

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