Patent ID: 9110247
Filing Date: 2015-08-18
Classification: G02B

Abstract:
1. An imaging lens comprising first, second, third, and fourth lens elements arranged from an object side to an image side in the given order, each of said first, second, third, and fourth lens elements having an object-side surface facing toward the object side and an image-side surface facing toward the image side, wherein: said first lens element has a positive refractive power, said object-side surface of said first lens element having a convex portion in a vicinity of an optical axis of said imaging lens, said image-side surface of said first lens element having a convex portion in a vicinity of the optical axis; said object-side surface of said second lens element has a convex portion in a vicinity of the optical axis, and said image-side surface of said second lens element has a concave portion in a vicinity of the optical axis; said fourth lens element has a negative refractive power, and said object-side surface thereof has a concave portion in a vicinity of the optical axis; wherein said imaging lens satisfies 10.5≧EFL/CT wherein said imaging lens does not include any lens element with refractive power other than said first, second, third, and fourth lens elements.