Patent ID: 7088528

Claim:
A single focus lens comprising, arranged along an optical axis in order from the object side: a stop on the object side of the single focus lens; a first lens component of positive refractive power and a meniscus shape, having both surfaces aspheric, and having its convex surface on the object side; a second lens component of positive refractive power and a meniscus shape, having both surfaces aspheric and, at least near the optical axis, having a convex surface on the object side; wherein the following conditions are satisfied: 0.20< R 1 / f< 0.70 0.05< D 2 / f 1<0.3 where R 1 is the radius of curvature on the optical axis of the object-side surface of the first lens component, f is the focal length of the entire single focus lens on the optical axis. D 2 is the distance on the optical axis from the image-side lens surface of the first lens component to the object-side lens surface of the second lens component, and f 1 is the focal length of first lens component on the optical axis; and the following condition is satisfied: 0.70< ΔZF/ΔZR< 1.20 where ΔZF is the object-side shape displacement at the maximum height at which an image forming light ray passes through the object-side surface of the first lens component, and ΔZR is the image-side shape displacement at the maximum height at which an image forming light ray passes through the image-side surface of the first lens component.