Patent ID: 8456759
Filing Date: 2013-06-04
Classification: G02B

Abstract:
1. A lens system for imaging an object on an image plane, the lens system comprising, in this order from the object side to the image side thereof: a first lens of positive refractive power; a second lens of negative refractive power; a third lens of positive refractive power; a fourth lens of positive refractive power, the fourth lens comprising an object-side surface facing the object side and an image-side surface facing the image side; and a fifth lens of negative refractive power; wherein the lens system satisfies the following condition formulas: where D is the diameter of optical images formed by the lens system on the image plane, TTL is the total length of the lens system, Z is the distance between an outer periphery of the image-side surface to the center of the object-side surface along a direction parallel to an optical axis of the lens system, Y is the distance between the outer periphery of the image-side surface to the center of the object-side along another direction perpendicular to the optical axis of the lens system, G3R1, G1R1, G2R2, G3R2, G5R1 G5R2 are the radii of curvature of an object-side surface of the third lens, an object-side surface of the first lens, an image-side surface of the second lens, an image-side surface of the third lens, an object-side surface of the fifth lens, and an image-side surface of the fifth lens, respectively, and F1, F3, F5 are focal lengths of the first, third, and fifth lenses, respectively.