Patent ID: 8331036

Claim:
An imaging lens system comprising, in order from an object side to an image side: a first lens element having a convex object-side surface and a concave image-side surface; a second lens element with positive refractive power, the object-side and image-side surfaces thereof being aspheric; a third lens element with negative refractive power, the object-side and image-side surfaces thereof being aspheric and at least one of the object-side and image-side surfaces having at least one inflection point; and an aperture stop disposed between the first and second lens elements; wherein there are only three lens elements with refractive power; and wherein a focal length of the imaging lens system is f, a focal length of the first lens element is f 1 , a radius of curvature of the object-side surface of the first lens element is R 1 , a radius of curvature of the image-side surface of the first lens element is R 2 , a thickness on the optical axis of the second lens element is CT 2 , a focal length of the second lens element is f 2 , and they satisfy the relations: |f/f 1 |<0.58, 0.20<R 1 /f<0.65, 0.00<R 2 /f<2.40, 0.10 mm<CT 2 <1.00 mm, 1.4<f/f 2 <2.3.