Lens apparatus and image pickup apparatus including the same

摘要

Lens apparatus includes adjacent concave and convex lens surfaces adjacent with an air layer therebetween. At least one of the lens surfaces includes an antireflection film including multiple subwavelength structures at an average pitch of 400 nm or smaller. The surface satisfies:
0.715°,
provided that:
D=f/FNo,θ1=sin−1(D/(2×fi)), andθ2=sin−1((h×D)/R2),where f and FNo represent focal length and F-number of the entire optical system, f1 represents focal length of an optical system on object side with respect to the air layer between the lens surfaces, h represents axial conversion beam height on the at least one surface having anti-reflection film, R1 and R2 represent curvature radii of surfaces of respective object and image sides between the lens surfaces.

主权项

1. A lens apparatus, comprising an optical system comprising a concave lens surface and a convex lens surface adjacent to each other with an air layer therebetween,
wherein at least one of the concave lens surface and the convex lens surface comprises an anti-reflection film comprising multiple subwavelength structures at an average pitch of 400 nm or smaller, and wherein the at least one of the concave lens surface and the convex lens surface satisfies the following expressions:
0.715°,provided that:
D=f/FNo, θ1=sin−1(D/(2×f1)), and θ2=sin−1((h×D)/R2)where f represents a focal length of the entire optical system, f1 represents a focal length of an optical system on an object side with respect to the air layer between the concave lens surface and the convex lens surface, FNo represents an F-number of the entire optical system, h represents an axial conversion beam height on the at least one of the concave lens surface and the convex lens surface having the anti-reflection film formed thereon, R1 represents a curvature radius of a surface situated on the object side between the concave lens surface and the convex lens surface, and R2 represents a curvature radius of a surface situated on an image side between the concave lens surface and the convex lens surface.