Patent ID: 8000033

Claim:
A photographing optical lens assembly 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; a second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, the object-side and image-side surfaces thereof being aspheric; a third lens element with negative refractive power having a convex object-side surface and a concave image-side surface, the object-side and image-side surfaces thereof being aspheric, and at least one inflection point being formed on the image-side surface; wherein the lens assembly is further provided with an electronic sensor disposed at an image plane for image formation of an object, and a stop disposed between the object and the first lens element; wherein a distance on an optical axis between the first lens element and the second lens element is T 12 ; a distance on the optical axis between the second lens element and the third lens element is T 23 ; a focal length of the lens assembly is f; a focal length of the second lens element is f 2 ; 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 radius of curvature of the object-side surface of the second lens element is R 3 ; a vertex of the image-side surface of the second lens element on the optical axis is T 2 ; when an image height of the system is half of a diagonal length of an effective pixel area of the electronic sensor, a farthest point of an effective light entry area on the image-side surface of the second lens element is P 2 ; a distance on the optical axis between T 2 and a vertical projection of P 2 on the optical axis is SAG 22 ; a distance between P 2 and its vertical projection on the optical axis is Y 22 ; a vertex of the object-side surface of the second lens element on the optical axis is T 1 ; when the image height of the system is half of the diagonal length of the effective pixel area of the electronic sensor, a farthest point of the effective light entry area on the object-side surface of the second lens element is P 1 ; a distance on the optical axis between T 1 and a vertical projection of P 1 on the optical axis is SAG 21 ; a distance between P 1 and its vertical projection on the optical axis is Y 21 ; a distance on the optical axis between the stop and the electronic sensor is SL; a distance on the optical axis between the object-side surface of the first lens element and the electronic sensor is TTL; and they satisfy the following relations: 0.35 <T 12 /T 23<1.95; −0.50 <f/f 2<−0.10; 0.00 <R 1 /R 2<0.32; −0.65 <R 3 /f<− 0.30; | SAG 21 /Y 21|<0.33; | SAG 22 /Y 22<0.23; and 0.90 <SL/TTL< 1.07.