Patent ID: 7518810

Claim:
A wide-angle lens comprising, in this order from the object side to the image side thereof, a first lens having negative refraction of power, a second lens having positive refraction of power, a third lens having positive refraction of power, and a fourth lens having negative refraction of power, In sequence, with no intervening lenses; wherein the wide-angle lens satisfies the formulas: R 1 >R 2 >0, R 1 /R 2 >4.5, R 8 <R 7 <0, and 2<|R 8 /R 7 |<2.25, where R 1 is the radius of curvature of the object-side surface of the first lens, R 2 is the radius of curvature of the image-side surface of the first lens, R 7 is the radius of curvature of the object-side surface of the fourth lens, and R 8 is the radius of curvature of the image-side surface of the fourth lens.