Patent ID: 8711493

Claim:
An imaging lens comprising first, second, third, and fourth lens elements arranged in order from an object side to an imaging side, each of the first, second, third, and fourth lens elements having an object-side surface facing toward the object side, and an imaging-side surface facing toward the imaging side, wherein the imaging lens satisfies the conditions of: 30 <vd 1 −vd 2; 0.5 <d 1avg/ d 2avg<0.9; and 0.4 <d 3avg/ d 4avg<0.7, wherein vd1 and vd2 are Abbe numbers of the respective first and second lens elements, and d1avg, d2avg, d3avg, and d4avg are average diameters of the first, second, third, and fourth lens elements, respectively; and wherein the imaging-side surface of the third lens element satisfies the following condition: 5.0 <sag 75 /sag 25<7.0, wherein sag25 is a sag value at a 25 percent point of a clear aperture of the imaging-side surface of the third lens element and sag75 is a sag value at a 75 percent point of the clear aperture of the imaging-side surface of the third lens element.