Imaging lens system

摘要

This invention provides an imaging lens system, in order from an object side to an image side comprising: a first positive lens element having a convex object-side surface at a paraxial region and a convex image-side surface at the paraxial region; a plastic positive second lens element having a concave object-side surface at the paraxial region, a convex image-side surface at the paraxial region, and both of the object-side and image-side surfaces being aspheric; and a plastic negative third lens element having a concave object-side surface at the paraxial region, a concave at the paraxial region and convex at a peripheral region image-side surface, and both of the object-side and image-side surfaces being aspheric.

主权项

1. An 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 at a paraxial region and a convex image-side surface at a paraxial region; a plastic second lens element with positive refractive power having a concave object-side surface at a paraxial region, a convex image-side surface at a paraxial region, and both of the object-side and image-side surfaces thereof being aspheric; and a plastic third lens element with negative refractive power having a concave object-side surface at a paraxial region, a concave at a paraxial region and convex at a peripheral region image-side surface, and both of the object-side and image-side surfaces thereof being aspheric; wherein the lens elements of the imaging lens system with refractive power are only the first lens element, the second lens element, and the third lens element, 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, a focal length of the first lens element is f1, a focal length of the second lens element is f2, and they satisfy the following relations:
−0.5<(R1+R2)/(R1−R2)<1.0; and1.65