Flat window - What kinds of spherical lens can be divided into?
A spherical lens is a refractor whose refracting surface is a transparent body with two spheres or one sphere and one plane. Generally, it can be divided into two categories: convex lens and concave lens. The central part thicker than the edge part is called convex lens, which has three kinds of biconvex, flat convex and concave convex; the central part thinner than the edge part is called concave lens, which has three kinds of biconvex, flat concave and convex concave. Convex lens has the function of converging line, so it is also called "converging lens" and "positive lens" (it can be used for hyperopia and presbyopia). This kind of lens can be divided into: A. biconvex lens, a lens whose two sides are grinded into convex spheres; B. planoconvex lens, a lens whose one side is convex and the other side is flat; C. concave convex lens, a lens whose one side is convex and the other side is concave. Concave lens has the function of divergent light, so it is also called "divergent lens" and "negative lens" (can be used for myopia glasses). This kind of lens can also be divided into: A. biconcave lens is a lens with two sides; B. flat concave lens is a lens with one side concave and one side flat; C. convex concave lens is a lens with one side convex and one side concave.
