Mobile device and optical imaging lens thereof

摘要

Present embodiments provide for a mobile device and an optical imaging lens thereof. The optical imaging lens may comprise an aperture stop and four lens elements positioned sequentially from an object side to an image side. By controlling the convex or concave shape of the surfaces of the lens elements and designing parameters satisfying at least two inequalities, the optical imaging lens may exhibit better optical characteristics and the total length of the optical imaging lens may be shortened.

主权项

1. An optical imaging lens, sequentially from an object side to an image side along an optical axis, comprising an aperture stop, and first, second, third and fourth lens elements, each of said first, second, third and fourth lens elements having refracting index, an object-side surface facing toward the object side and an image-side surface facing toward the image side and a central thickness defined along the optical axis, wherein:
said object-side surface of said first lens element comprises a convex portion in a vicinity of a periphery of the first lens element, and said image-side surface of said first lens element comprises a convex portion in a vicinity of the periphery of the first lens element; said second lens element has negative refracting index, and said object-side surface of said second lens element comprises a concave portion in a vicinity of the optical axis and a concave portion in a vicinity of a periphery of the second lens element; said third lens element has positive refracting index, and said object-side surface of said third lens element comprises a concave portion in a vicinity of the optical axis and a concave portion in a vicinity of a periphery of the third lens element, and said image-side surface thereof comprises a convex portion in a vicinity of the periphery of the third lens element; said image-side surface of said fourth lens element comprises a concave portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the fourth lens element; the optical imaging lens comprises no other lenses having refracting index beyond the four lens elements; and the central thickness of the second lens element is represented by T2, the central thickness of the fourth lens element is represented by T4, an air gap between the third lens element and the fourth lens element along the optical axis is represented by G34, a sum of the central thicknesses of all four lens elements is represented by ALT, and T2, T4, G34 and ALT satisfy the inequalities: ALT/T2≦5.4; and (T2+T4)/G34≦4.0.