The lens has an external convex mirror and an internal concave mirror surface. If the convex radian is greater than the concave radian, the lens has a positive focal length and is used as a magnifying glass. If the concave side curvature is large and the convex side curvature is small, it is a negative meniscus lens, and the negative meniscus lens can be used to replace other negative lenses. The meniscus lens is used to reduce spherical aberration to a large extent, and can obtain a smaller focus and less aberration than the plano-convex lens to improve the image quality. When combined with another lens, a positive meniscus lens can shorten the focal length, thereby increasing the numerical aperture (NA) of the system without introducing significant spherical aberrations. When used for converging collimating light, the convex surface of the lens should face the light source.