Patent ID: 7738191

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> f 1 /f> 0.6 (1) 24.0<νdA<32.0 (2) 55.5<νdB<58.5 (3) 1.55<NdA (4) 1.47<NdB<1.55 (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 second lens, νdB: Abbe number of the first lens and the third lens, NdA: Refractive index at d-line of the second lens, NdB: Refractive index at d-line of the first lens and the third lens, RA: Paraxial curvature radius of a surface at the object side of the first lens, L: Distance on the optical axis from the surface at the object side of the first lens to an imaging position, and D: Maximum image height.