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Wide-angle objective for endoscopes

  • US 4,858,002 A
  • Filed: 04/11/1988
  • Issued: 08/15/1989
  • Est. Priority Date: 04/11/1987
  • Status: Expired due to Term
First Claim
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1. A wide-angle objective for an endoscope, said objective having a distal side facing an object and an image side, a meniscus being located at the distal side with a concave first surface facing towards the object, another optical component being of the meniscus, the improvements comprising said meniscus being a distal meniscus with said first surface having a first radius r1, said distal meniscus having a second surface with a second radius r2 facing toward said another optical component, said another optical component being a proximal meniscus having a first surface with a radius r3 facing toward the distal meniscus and a second surface with a radius r4 facing towards said image side of the objective, said objective having a field of view angle α

  • and an overall focal length of F, said distal meniscus having a focal length of f1 and said proximal meniscus having a focal length f2, and the proximal and distal menisci having the following dimensions;

    ##EQU2## wherein nd is an index of refraction for a wavelength of 580 nm; and

    Vd is an abbe coefficient for a wavelength of 580 nm.

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