Patent ID: 7911716

Claim:
A lens module, comprising: a first lens group disposed between a magnified side and a reduced side, having a positive refractive power, and comprising in sequence from the magnified side to the reduced side: a first sub-lens group having a negative refractive power and a second sub-lens group having a positive refractive power, wherein the first sub-lens group comprises a first lens and the second sub-lens group comprises a second lens, and a first surface of the first lens facing the magnified side is a concave surface; a second lens group disposed between the first lens group and the reduced side, having a negative refractive power, and comprising in sequence from the magnified side to the reduced side: a third lens having a positive refractive power and a fourth lens having a negative refractive power, wherein a surface closest to the reduced side in the second lens group is a second surface; a third lens group disposed between the second lens group and the reduced side, having a positive refractive power, and comprising a fifth lens, wherein a surface closest to the magnified side in the third lens group is a third surface; and an aperture stop disposed between the second sub-lens group and the second lens group, wherein an effective focal length of the lens module is f, a distance from a center of the second surface to a center of the third surface is L 1 , and the lens module satisfies 0.4<L 1 /f<1.2.