Patent ID: 6603610
Filing Date: 2003-08-05
Classification: G02B

Abstract:
A wide-angle lens system comprising a negative first lens group and a positive second lens group, in this order from an object,said first lens group comprising a positive lens element and at least one negative lens element, in this order from the object, and said second lens group comprising at least one aspherical surface, said at least one aspherical surface satisfying the following condition: âˆ’0.20 wherein&Dgr;V designates an aspherical-surface term in a distortion coefficient; wherein the wide-angle lens system satisfies the following conditions: 01-2+&phgr;2-1)/&phgr;<0.3 0.5<HF/HL<0.9 wherein&phgr;1-2=(1âˆ’n1)/r1-2; &phgr;2-1=(n2âˆ’1)/r2-1; &phgr;=1/f; n1 designates a refractive index of said positive lens element of said first lens group; n2 designates a refractive index of a most object-side negative lens element of said first lens group; r1-2 designates a radius of curvature of an image-side surface of said positive lens element of said first lens group; r2-1 designates a radius of curvature of an object-side surface of the most object-side negative lens element of said first lens group; f designates a focal length of the wide-angle lens system; HF designates a radius of a bundle of axial light rays with respect to a most object-side surface of said first lens group; and HL designates a radius of a bundle of axial light rays with respect to a most object-side surface of said second lens group.