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Wide-angle lens assembly and method

  • US 6,018,425 A
  • Filed: 09/29/1997
  • Issued: 01/25/2000
  • Est. Priority Date: 09/30/1996
  • Status: Expired due to Fees
First Claim
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1. A wide angle lens system comprising:

  • a combination of a first lens and a second lens which are respectively selected from a first group of discrete bi-concave lenses which have an aspherical surface on one face thereof and are fabricated respectively corresponding to each of horizontal viewing angles covered by the wide-angle lens system, and from a second group of identical bi-convex lenses which are provided with aspherical surfaces on both faces thereof and are fabricated respectively corresponding to each of horizontal viewing angles covered by the wide-angle lens system, said first lens and said second lens being aligned along an optical axis from an object side to an image side such that the first lens is positioned on the object side with respect to the second lens, the aspherical surface of the first lens being faced to the object side, wherein;

    the combination of the first lens and the second lens provides a wide angle view and satisfies the following conditions;

    0.65f2<

    bf<

    0.8f2-1.8f2<

    -1.1f2, andwhere f1 is a focal distance of the first lens, f2 is a focal distance of the second lens, and bf is a distance of back focus from the second lens to a focus point thereof in each discrete combination of the first lens and the second lens.

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