Patent ID: 8665538

Claim:
An imaging lens apparatus, comprising: a first lens with a convex object-side surface and positive refractive power, at least one surface of the first lens is aspheric; a second lens which is a biconcave lens with negative refractive power, at least one surface of the second lens is aspheric; an aperture stop located between the first lens and the second lens, for controlling the ray cone that come to focus at the image plane; a third lens which is a positive meniscus lens with a concave object-side surface, both side of the third lens are aspheric; and a fourth lens which is a negative meniscus lens with a convex object-side surface, both side of the fourth lens are aspheric with at least one inflection point; and wherein the imaging lens apparatus satisfies the conditions below: |1/slope — S 8|>0.9 −0.2 <SAG — S 8 /SD — S 8<0.1 wherein slope_S8 is the slope of the periphery of the image-side surface of the fourth lens in the imaging lens apparatus; SD_S8 is the vertical distance between the periphery of the image-side surface of the fourth lens and the optical axis; and SAG_S8 is the sag of the image-side surface of the fourth lens related to SD_S8.