Patent ID: 8937775
Filing Date: 2015-01-20
Classification: G02B

Abstract:
1. An imaging lens comprising: a first lens element; a second lens element; a third lens element; and a fourth lens element, wherein each of the first lens element, the second lens element, the third lens element, and the fourth lens element are arranged in order from an object side to an image side along an optical axis of the imaging lens, have a refractive power, an object-side surface facing toward the object side, and an image-side surface facing toward the image side, wherein: the first lens element has a positive refractive power and the image-side surface of the first lens element has a convex portion in a vicinity of a periphery of the first lens element; the object-side surface of the second lens element has a concave portion in a vicinity of the optical axis and a concave portion in a vicinity of a periphery of the second lens element, and the image-side surface of the second lens element has a concave portion in a vicinity of the optical axis and a concave portion in a vicinity of a periphery of the second lens element; the third lens element has a positive refractive power and the object-side surface of the third lens element has a concave portion in a vicinity of a periphery of the third lens element; the fourth lens element has a negative refractive power and the image-side surface of the fourth lens element has a concave portion in a vicinity of the optical axis; the imaging lens does not include any lens element with a refractive power other than the first lens element, the second lens element, the third lens element, and the fourth lens element; and the imaging lens satisfies the following relations: wherein ALT is a sum of thicknesses of the first lens element to the fourth lens element along the optical axis, T1 is a thickness of the first lens element at the optical axis, AG34 is an air gap length between the third lens element and the fourth lens element along the optical axis, and T4 is a thickness of the fourth lens element along the optical axis.