The application discloses a fixed-focus lens, which comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens arranged in sequence along an
optical axis from an object plane to an
image plane; the object side surface of the first lens is a convex surface, and the image side surface is a
concave surface; the object side surface of the second lens is a convex surface, and the image side surface is a
concave surface; the object side surface of the third lens is a
concave surface, and the image side surface is a convex surface; and the object side surface of the eighth lens is a convex surface, and the image side surface is a convex surface. By arranging the fixed-focus lens to comprise eight lenses and by reasonably arranging the surface shapes of the first lens, the second lens, the third lens and the eighth lens, the
machining difficulty of the lens is reduced, the illumination of the lens and the sensitivity of the lens are improved, the aberration of the lens is balanced, the imaging effect of the fixed-focus lens is improved, and the characteristics of being capable of matching a 1''
target surface sensor
chip and being capable of giving consideration to wide angle and
low distortion and the maximum image surface being up to 16.1 mm are achieved.