Imaging lens and imaging apparatus
AssigneeFujinon Corporation
InventorsTakashi Suzuki, Taro Asami
Life of this patent
Estimating the term…
Abstract
An imaging lens is provided and includes: 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. The lens group has an air lens formed by an air gap between lenses adjacent to each other, and the imaging lens satisfies conditional expression (1): −8<L×(1/Ra2−1/Ra1)<−3 (1) Ra1 represents a radius of curvature of an object-side surface of the air lens which has a convex shape and is closest to an image side of the imaging lens in the lens group, Ra2 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 tens from an object-side surface of a lens closest to an object side in the imaging lens to an imaging plane.
Claims15
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):
- −8<L×(1/Ra2−1/Ra1)<−3 (1)
- wherein Ra1 represents a radius of curvature of an object-side surface of the air lens, Ra2 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.
Dependencies are inferred from the claim text.