Patent ID: 8068290

Claim:
An image pick-up 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 convex image-side surface; a second lens element with negative refractive power having a concave object-side surface and a convex image-side surface; a third lens element with positive refractive power having an object-side surface and a convex image-side surface, at least one of the surfaces thereof being aspheric; and a fourth lens element with negative refractive power having a convex object-side surface and a concave image-side surface, at least one of the surfaces thereof being aspheric; wherein the image pick-up optical lens assembly further comprises an aperture stop disposed between an object and the first lens element; wherein the number of lens elements with refractive power is four; and wherein a combined thickness of the lens elements with refractive power on an optical axis is Σ ⁢ ⁢ CT Td , a distance on the optical axis between the object-side surface of the first lens element and the image-side surface of the fourth lens element is Td, 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 focal length of the image pick-up optical lens assembly is f, a focal length of the second lens element is f 2 , a focal length of the third lens element is f 3 , a focal length of the fourth lens element is f 4 , a distance on the optical axis between the first lens element and the second lens element is T 12 , and they satisfy the relations: 0.80 < Σ ⁢ ⁢ CT Td < 0.98 ; 0.15 < ( R ⁢ ⁢ 1 + R ⁢ ⁢ 2 ) / ( R ⁢ ⁢ 1 - R ⁢ ⁢ 2 ) < 1.0 ; 0.4 < ( f / f 2 ) + ( f / f 3 ) f / f 4 < 1.7 ; and ⁢ ⁢ 0.0 < T ⁢ ⁢ 12 / f < 0.10 .