Patent ID: 7515358

Claim:
An optical lens system for taking image, from object side along the optical axis comprising: an aperture stop, a first lens element, a second lens element, and a third lens element, wherein: the first lens element is a positive meniscus plastic lens element with its convex surface facing the object side; the second lens element is a negative meniscus plastic lens element with its convex surface facing the image side; and the third lens element is a positive meniscus plastic lens element with its convex surface facing the object side; both surfaces of each lens elements are aspheric; a focal length of the optical lens system is f; a focal lens of the first lens element is f 1 ; the focal length of the second lens system is f 2 ; a radius of curvature of object side surface of the first lens element is R 1 , a radius of curvature of image side surface of the first lens element is R 2 , a radius of curvature of the object side surface of the second lens element is R 3 , and a radius of curvature of the image side surface of the second lens element is R 4 , and they satisfy the relations: 0.7< f 1/ /f< 0.9 −3.5 <f 2 /f <−1.2 0.6< R 3 /R 4<0.8 0.20< R 1/ R 2<0.55.