Patent ID: 8891178
Filing Date: 2014-11-18
Classification: G02B

Abstract:
1. An optical lens system, in order from an object side to an image side comprising: a first lens element having a convex object-side surface in proximity to an optical axis; a second lens element with negative refractive power having a concave object-side surface in proximity to the optical axis and a convex image-side surface in proximity to the optical axis; a third lens element with positive refractive power having a convex object-side surface in proximity to the optical axis and a convex image-side surface in proximity to the optical axis; a plastic fourth lens element with negative refractive power having a concave object-side surface in proximity to the optical axis and a convex image-side surface in proximity to the optical axis, with both the object-side and image-side surfaces thereof being aspheric; wherein the optical lens system comprises a total of four lens elements with refractive power; wherein a focal length of the fourth lens element is f4, a focal length of the optical lens system is f, an axial distance between the second lens element and the third lens element is T23, an axial distance between the third lens element and the fourth lens element is T34, a central thickness of the third lens element is CT3, a focal length of the first lens element is f1, and they satisfy the following relations: