Patent ID: 8885232

Claim:
A scanner lens comprising: a first lens group having a positive refractive power, comprising a first positive lens and a second negative lens which are cemented; a second lens group comprising a third negative lens; a third lens group comprising a fourth positive lens; a fourth lens group comprising a fifth negative lens; a fifth lens group comprising a sixth negative lens, the first to fifth groups being arranged in order from an object side to an image side; and an aperture stop disposed between the first lens group and the second lens group, wherein the scanner lens is configured to satisfy the following three conditions: 0.01<BF/ L< 0.10 0.50 <f 1 /f< 9.5 0.20 <d 10 /f< 0.90 where BF is a back focus of the scanner lens, L is a total lens length, f1 is a focal length of an e-line of the first lens group, f is a focal length of an e-line of an entire lens system and d10 is an air space between the fifth and six lenses.