Patent ID: 8587872

Claim:
A lens module, comprising: a first lens group having a positive refractive power and essentially consisting of a first lens with a negative refractive power, a second lens with a positive refractive power and a third lens with a positive refractive power arranged in order from a magnified side to a reduced side; a second lens group disposed between the first lens group and the reduced side, the second lens group having a negative refractive power and essentially consisting of a fourth lens with a negative refractive power and a fifth lens with a positive refractive power arranged in order from the magnified side to the reduced side; a third lens group disposed between the second lens group and the reduced side, the third lens group having a positive refractive power and essentially consisting of a sixth lens with a positive refractive power and a seventh lens with a positive refractive power arranged in order from the magnified side to the reduced side; and an aperture stop disposed between the first lens group and the second lens group, wherein the first lens group, the aperture stop and the second lens group are moved together to function as a focusing lens group, and the third lens group is fixed.