Patent ID: 6930841

Claim:
A single focus lens comprising, arranged along an optical axis in order from the object side: a first lens component having positive refractive power, having a convex object-side surface, and being made of glass; a stop; a second lens component having a meniscus shape with a concave object-side surface, being made of plastic, and having at least one aspheric surface; a third lens component having a meniscus shape with a convex object-side surface, being made of plastic, and each of the object-side surface and the image-side surface being aspheric; wherein the following conditions are satisfied: 1.0 <f 1 / f <2.5 R 1 / f <3.0 1.0 <ΔZF/ΔZR <2.0 0.3 <ΔZRA/ΔZR <0.6 0.7<( Bf−ΔZR )/ M 0.6<(| R 2 |− R 1 )/( R 1 +| R 2 |) where f 1 is the focal length of the first lens component, f is the focal length of the single focus lens, R 1 is the radius of curvature of the object-side surface of the first lens component, ΔZF is the object-side shape displacement at the maximum height at which an image forming light ray passes through the image-side surface of the third lens component, 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 third lens component, ΔZRA is the image-side shape displacement at one-half the maximum height at which an image forming light ray passes through the image-side surface of the third lens component, Bf is the back focal length of the single focus lens based on air being between the image-side surface of the single focus lens and the image plane, M is the maximum image height at the image plane, and R 2 is the radius of curvature of the image-side surface of the first lens component.