Patent ID: 7859770

Claim:
A fixed-focus lens, comprising: a first lens group, disposed between a magnified side and a reduced side and comprising a first lens and a second lens arranged in sequence from the magnified side to the reduced side, wherein the refractive powers of both the first lens and the second lens are negative, and the first lens is an aspheric lens; and a second lens group, disposed between the first lens group and the reduced side and comprising a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens arranged in sequence from the magnified side to the reduced side, wherein the refractive powers of the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are respectively positive, negative, positive, negative, positive, negative, and positive in sequence, the effective focal length of the fixed-focus lens is F, the image height at the reduced side is H, and F/H>0.627.