Patent ID: 9405097
Filing Date: 2016-08-02
CPC Classification: G02B

Claim Text:
1. An imaging lens comprising a first lens element, a second lens element, a third lens element and a fourth lens element arranged in order from an object side to an image side along an optical axis of said imaging lens, each of said first lens element, said second lens element, said third lens element and said fourth lens element having a refractive power, an object-side surface facing toward the object side, and an image-side surface facing toward the image side, wherein: said image-side surface of said first lens element has a concave portion in a vicinity of a periphery of said first lens element; said second lens element has a positive refractive power; said image-side surface of said third lens element has a convex portion in a vicinity of the optical axis; said fourth lens element has a negative refractive power, and said image-side surface of said fourth lens element has a concave portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of said fourth lens element; said imaging lens does not include any lens element with refractive power other than said first lens element, said second lens element, said third lens element and said fourth lens element; and said imaging lens satisfies 2.5≦BFL/G