| 主权项 |
1. An imaging lens comprising a first lens element, an aperture stop, a second lens element, a third lens element, a fourth lens element and a fifth 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, said fourth lens element and said fifth 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 object-side surface of said first lens element has a convex portion in a vicinity of a periphery of said first lens element, and said image-side surface of said first lens element has a convex portion in a vicinity of the optical axis; said second lens element is made of a plastic material; said object-side surface of said third lens element has a concave portion in a vicinity of a periphery of said third lens element; said fourth lens element has a positive refractive power, and said object-side surface of said fourth lens element has a concave portion in a vicinity of the optical axis; said object-side surface of said fifth lens element has a convex portion in a vicinity of the optical axis, and a concave portion in a vicinity of a periphery of said fifth lens element; and 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, said fourth lens element and said fifth lens element, and satisfies (T1+T3)/Gaa≧1.2, where T1 represents a thickness of said first lens element at the optical axis, T3 represents a thickness of said third lens element at the optical axis, and Gaa represents a sum of four air gap lengths among said first lens element, said second lens element, said third lens element, said fourth lens element and said fifth lens element at the optical axis. |
