Patent ID: 8351136

Claim:
An optical imaging lens system, in order from an object side to an image side comprising: a first lens element with positive refractive power having a convex object-side surface and a concave image-side surface, wherein the portion of the object-side surface of the first lens element in proximity to the optical axis is convex and the portion of the image-side surface of the first lens element in proximity to the optical axis is concave; a second lens element with negative refractive power having a convex object-side surface and a concave image-side surface; a third lens element with positive refractive power; and a fourth lens element having a concave image-side surface, and at least one of the object-side and image-side surfaces thereof being aspheric; wherein the optical imaging lens system further comprises an aperture stop and an electronic sensor on which an object is imaged, and the aperture stop is positioned between an object and the first lens element; wherein there are four lens elements with refractive power; wherein a focal length of the optical imaging lens system is f, a focal length of the third lens element is f 3 , a focal length of the fourth lens element is f 4 , an on-axis spacing between the first lens element and the second lens element is T 12 , an on-axis spacing between the second lens element and the third lens element is T 23 , a distance on the optical axis between the aperture 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 relation: 0 <f/f 3<0.9; | f/f 4|<0.75; 0 <T 12 /T 23<0.27; and 0.9 <SL/TTL< 1.2.