摘要 |
An imaging lens includes plastic-made first, second, third, and fourth lens elements arranged in the given order from an object side to an imaging side. The first lens element has a positive focusing power and is biconvex. The second lens element has a negative focusing power, is biconcave, and has an abbe number not greater than 30. The third lens element has a positive focusing power and has a convex imaging-side surface facing toward the imaging side. The fourth lens element has an imaging-side surface formed with a concave area in a vicinity of an optical axis of the fourth lens element. The imaging lens further includes an aperture stop disposed between the first and second lens elements. |
主权项 |
1. An optical imaging lens comprising, from an object side to an image side, a first lens element, a second lens element, a third lens element, and a fourth lens element, each of the first, second, third, and fourth lens element having an object-side surface facing toward the object side and an image-side surface facing toward the image side, wherein:
the object-side surface of the first lens element has a convex portion in a vicinity of an optical axis and a convex portion near a circumference of the first lens element; the second lens element has a negative refracting power; the third lens element has a positive refracting power, the object-side surface of the third lens element has a concave portion in a vicinity of an optical axis, and the image-side surface of the third lens element has a convex portion in a vicinity of an optical axis; the fourth lens element has a negative refracting power and the image-side surface of the fourth lens element has a concave portion in a vicinity of the optical axis and a convex portion near the circumference of the fourth lens element; the optical imaging lens has only four lens elements having a refracting power; and the optical imaging lens satisfies the relation:
0.76≦AG23/AG12≦2.33, wherein AG12 is a width of an air gap between the first and second lens elements along the optical axis, and AG23 is a width of an air gap between the second and third lens elements along the optical axis. |