Patent ID: 8817389

Claim:
An optical lens assembly for image taking comprising, in order from an object side to an image side: a first lens element with positive refractive power comprising a convex object-side surface at a paraxial region and an image-side surface; a second lens element with negative refractive power comprising a concave object-side surface at a paraxial region and an image-side surface; a third lens element with refractive power comprising a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region; and a fourth lens element made of plastic with negative refractive power comprising a concave object-side surface at a paraxial region and a concave image-side surface at a paraxial region wherein at least one of the object-side surface and the image-side surface is aspheric, and the image-side surface is convex at a peripheral region; wherein T 23 is an axial distance between the second lens element and the third lens element, CT 3 is a central thickness of the third lens element, R 1 is a curvature radius of the object-side surface of the first lens element, R 2 is a curvature radius of the image-side surface of the first lens element, Dr 1 r 4 is an axial distance between the object-side surface of the first lens element and the image-side surface of the second lens element, and the optical lens assembly for image taking satisfies the following conditions: 1.45 <T 23 /CT 3 <3.0; −0.15 <R 1 /R 2 <0.50; and 0.70 <Dr 1 r 4 /T 23 <1.08.