Patent ID: 9116325
Filing Date: 2015-08-25
Classification: G02B

Abstract:
1. An imaging lens system for imaging a subject image on an image sensing surface of an image sensing device, the imaging lens system comprising, from an object side: an aperture stop; a first lens element having a positive optical power and convex to the object side; a second lens element having a negative optical power; a third lens element having a positive optical power and convex to the object side; a fourth lens element having a positive optical power and having a meniscus shape convex to the image side; and a fifth lens element having a negative optical power and having a biconcave shape, wherein an image-side surface of the fifth lens element has, on a sectional plane including an optical axis, a point, other than an intersection with the optical axis, at which a tangent line is perpendicular to the optical axis, conditional formulae (1) to (4) below are fulfilled: where f represents a focal length of the entire imaging lens system; f1 represents a focal length of the first lens element; f4 represents a focal length of the fourth lens element; d3 represents an axial thickness of the second lens element; d4 represents an axial aerial distance between the second and third lens elements; and R3 wherein an image-side surface of the third lens element has a negative optical power in a peripheral part.