Patent ID: 7199948
Filing Date: 2007-04-03
Classification: G02B

Abstract:
1. 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: 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.