Patent ID: 8274593

Claim:
An optical lens system comprising, in order from an object side to an image side: a first lens element with negative refractive power having a convex object-side surface and a concave image-side surface; a second lens element with positive refractive power; a third lens element with positive refractive power, both object-side and image-side surfaces of the third lens element being aspheric; a fourth lens element with negative refractive power having a concave image-side surface, both object-side and image-side surfaces of the fourth lens element being aspheric; wherein there are four lens elements with refractive power, a distance on an optical axis between the first lens element and the second lens element is T 12 , a focal length of the optical lens system is f, a center thickness of the first lens element is CT 1 ; wherein the optical lens system is further provided with an aperture stop, a distance from the aperture stop to an image plane along the optical axis is SL, a distance from the object-side surface of the first lens element to the image plane along the optical axis is TTL, and they satisfy the relations: 0.1 <T 12 /f< 0.3; 0.30 <CT 1 /f< 0.75; 0.52 <SL/TTL< 0.82.