| 摘要 |
<p>An imaging lens includes first, second, third, and fourth lens elements arranged from an object side to an image side in the given order. The first lens element has a positive refractive power, and both of the object-side and image-side surfaces thereof have a convex portion near an optical axis of the imaging lens. The object-side and image-side surfaces of the second lens element respectively have a convex portion and a concave portion near the optical axis. The fourth lens has a negative refractive power, and the object-side surface thereof has a concave portion near the optical axis. The imaging lens satisfies EFL/CT1≧5.3, where EFL is an effective focal length of the imaging lens, and CT1 is a thickness of the first lens element.</p> |
