subject: Types Of Optical Lens [print this page] An optical lens has a perfect or approximate axial symmetry for light transmission and refraction. Based on different elements, optical lenses can be differently classified.
If an optical lens has only one optical element (one focal point), it is called a simple lens. Lenses with multiple optical elements (multiple focal points) are called compound optical lenses. From the material aspect, optical lens has types of plastic lenses, glass lenses, and polycarbonate lenses etc By curvature of the two lens surfaces, optical lenses can be divided into mainly concave lenses and convex lenses. The following is a detail description on this point.
There are still several variations within convex optical lens. The first type is biconvex, which has two convex surfaces. So that it is also named double convex. This is the standard convex optical lens type. More exactly, if both surfaces have the same radius of curvature, the optical lens is called equi-convex. The second type is plano-convex optical lenses if one surface is flat and the other is convex.
Optical lenses with two concave surfaces are named biconcave, or just concave. This is the standard concave lens. Secondly, optical lens with a flat surface and a concave surface is called plano-concave.
Although corrective lenses can be made of many of the above lenses types, the most common used optical lens is concave-convex. This kind of optical lenses have one convex side and one concave side. For hyperopia and presbyopia correction, a convergent optical lens is used, and for myopia correction a divergent lens. All these two types can be made from concave-convex lenses with different curvatures between the front and rear surface.
