Patent ID: 7199948

Claim:
A single focus lens comprising: a first lens of positive power having a convex-shaped surface on an object side; a second lens of a negative meniscus lens having, on the object side, a concave-shaped surface on its paraxial axis; and a third lens of an aspheric lens having, on the object side, a convex-shaped surface on its paraxial axis, in this order from the object side, wherein the single focus lens satisfies the following conditions: 1.5>f1/f>0.6 (1) 69<ν (2) 55<νdB<59 (3) 1.55>NdA (4) 1.55>NdB>1.48 (5) 1.8>L/D (6) 0.30<RA/f<0.40 (7) where f: Entire focal distance, f1: Focal distance of the first lens, νdA: Abbe number of the first lens, νdB: Abbe number of the second lens and the third lens, NdA: Refractive index at d-line of the first lens, NdB: Refractive index at d-line of the second lens and the third lens, RA: Paraxial curvature radius of a surface at the object side of the first lens, L: Distance on an optical axis from the surface at the object side of the first lens to an imaging position, and D: Maximum image height.