AT001 عدسة هلالية 420 مم - 680 مم H-LAK2A

A positive crescent lens is composed of two curved surfaces with similar radii of curvature and has a positive focal length. Usually used to reduce the focal length of another lens, increase the numerical aperture, and other related applications. To reduce spherical aberration, the beam should be incident on the convex surface of the lens when expanding, contracting, or diverging collimated light applications; When used for converging and collimating light, the beam is incident on a concave surface.
The positive crescent lens is mainly used to minimize spherical aberration. When used in combination with another lens, the positive meniscus lens can reduce the focal length and increase the system numerical aperture (NA) without introducing significant spherical aberration. When used to converge parallel light, in order to minimize spherical aberration, the convex surface of the lens should face the direction of the light source emission. Coated lenses are also widely used in visible and near-infrared applications.