Optical Lenses

Lenses are classified by the curvature of these two surfaces. A lens is biconvex (or just convex) if both surfaces are convex, likewise, a lens with two concave surfaces is biconcave (or concave). If one of the surfaces is flat, the lens is termed plano-convex or plano-concave depending on the curvature of the other surface. A lens with one convex and one concave side is termed convex-concave, and in this case if both curvatures are equal it is a meniscus lens. Optical Lenses illustrates the function of convex and concave optical lenses. Both the size and the distance of the object and the focal length may be adjusted by the user.