Patent ID: 8670190

Claim:
An imaging lens system including, in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface; a second lens element with negative refractive power; a third lens element; a fourth lens element with positive refractive power having a convex image-side surface; and a fifth lens element with negative refractive power having a convex object-side surface and a concave image-side surface, the object-side and image-side surfaces thereof being aspheric, at least one surface thereof being provided with at least one inflection point; wherein the lens elements with refractive power in the imaging lens system are only the first, second, third, fourth and fifth lens elements; a focal length of the fourth lens element is f 4 , a focal length of the fifth lens element is f 5 , and they satisfy the relation: −1.5<f 4 /f 5 <−0.5.