| 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, wherein each of the first lens element, the second lens element, the third lens element, and the fourth lens element have an object-side surface facing toward the object side and an image-side surface facing toward the image side, wherein: the first lens element has a positive refracting power, 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, and the image-side surface of the first lens element has a convex portion in a vicinity of the optical axis and a convex portion near the circumference of the first lens element; the second lens element has a negative refracting power, the object-side surface of the second lens element has a concave portion in a vicinity of the optical axis and a concave portion near a circumference of the second lens element, and the image-side surface of the second lens element has a concave portion in a vicinity of the optical axis; 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 the optical axis, and the image-side surface of the third lens element has a convex portion in a vicinity of the 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 a 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 following relations: 0.430≦AG12/AG23≦1.303, 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. |
