Patent ID: 8537474

Claim:
An imaging lens system comprising, in order from an object side to an image side: a first lens element with positive refractive power; a plastic second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, both surfaces thereof being aspheric; and a plastic third lens element with negative refractive power having a convex object-side surface and a concave image-side surface, both surfaces thereof being aspheric, and at least one inflection point is formed on at least one of the object-side and image-side surfaces thereof; wherein there are three lens elements with refractive power in the imaging lens system; the second lens element has the greatest central thickness among the three lens elements; a central thickness of the first lens element is CT1, a central thickness of the second lens element is CT2, a central thickness of the third lens element is CT3, a curvature radius of the object-side surface of the first lens element is R1, a curvature radius of the image-side surface of the first lens element is R2, an axial distance between the second lens element and the third lens element is T23, and they satisfy the following relations: 0.35 <CT 1 /CT 2<1.00; 0.35 <CT 3 /CT 2<1.00; −3.0<( R 1 +R 2)/( R 1 −R 2)<0; and 0.65 <T 23 /CT 3<1.80.