Patent ID: 7957076

Claim:
An optical lens system for taking image comprising, in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface and a concave image-side surface, the object-side and the image-side surfaces of the first lens element being aspheric; a second lens element with positive refractive power having a convex object-side surface and a concave image-side surface, the object-side and the image-side surfaces of the second lens element being aspheric; the first lens element and the second lens element made of plastic material; an aperture stop located between an object to be photographed and the first lens element; a radius of curvature of the object-side surface of the first lens element being R 1 , a radius of curvature of the object-side surface of the second lens element being R 3 , a radius of curvature of the image-side surface of the second lens element being R 4 , a focal length of the optical lens system for taking image being f, a focal length of the first lens element being f 1 , a focal length of the second lens element being f 2 , an on-axis distance between the first lens element and the second lens element being T 12 , a center thickness of the second lens element being CT 2 , and they satisfying the relations: 0.76 mm −1 <1 /R 1<2.0 mm −1 ; 0.4 <R 3 /R 4<1.15; 0.35<( f/f 1)−( f/f 2)<0.72; T 12 /CT 2>1.0; 0.5 <f/f 1<1.0; 0.15 <f/f 2<0.45 and in the optical lens system for taking image, the number of lens elements with refractive power being only two.