Patent ID: 8804253

Claim:
An image lens system comprising, 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 plastic third lens element having a concave image-side surface, both the object-side and image-side surfaces thereof being aspheric; a plastic fourth lens element with positive refractive power having a convex object-side surface and a convex image-side surface, both the object-side and image-side surfaces thereof being aspheric; and a plastic fifth lens element with negative refractive power having a concave image-side surface, both the object-side and image-side surfaces thereof being aspheric, at least one inflection point is formed on at least one of the object-side and image-side surfaces thereof; wherein there are air distances between the first lens element, the second lens element, the third lens element, the fourth lens element and the fifth lens element; wherein the image lens system comprises a total of five lens elements with refractive power; wherein a focal length of the image lens system is f, a focal length of the fourth lens element is f4, an axial distance between the third lens element and the fourth lens element is T34, an axial distance between the fourth lens element and the fifth lens element is T45, and they satisfy the following relations: 0<f/f4<0.95; and 0<T34/T45<2.85.