Patent ID: 7889441

Claim:
A lens system comprising: a first lens of a biconvex type having two aspherical surfaces; a second lens of a biconcave type having at least one aspherical surface; a third lens having two aspherical surfaces and having a positive refracting power; and a fourth lens having two aspherical surfaces and having a negative refracting power, wherein the first lens, the second lens, the third lens, and the fourth lens are arranged sequentially from an object side of the lens system to an image side of the lens system; wherein an aspherical surface of an image side of the fourth lens comprises an inflection point within an effective aperture range, wherein |L1R1|>|L1R2|, where L1R1 is a radius of curvature of an object side of the first lens, and L1R2 is a radius of curvature of an image side of the first lens, and wherein 0.8<|L1R2|/|L2R2|<1.1, where L2R2 is a radius of curvature of an image side of the second lens.