Patent ID: 7889442
Filing Date: 2011-02-15
Classification: G02B

Abstract:
1. An imaging lens comprising: a stop; and a lens group disposed between the stop and an imaging plane of the imaging lens and having a positive power as a whole, wherein the lens group has an air lens with a positive power formed by an air gap between lenses adjacent to each other, the air lens being disposed in the lens group to be closer to an image side of the lens group than to an object side, and the imaging lens satisfies conditional expression (1): wherein Ra 1 represents a radius of curvature of an object-side surface of the air lens, Ra 2 represents a radius of curvature of an image-side surface of the air lens, and L represents a distance on an optical axis of the imaging lens from an object-side surface of a lens closest to an object side of the imaging lens to the imaging plane, wherein at least one lens surface exposed to the air lens has an anti-reflection coating having a reflectance of less than 2% for light having a wavelength of 800 nm.