What is the difference between concavo-convex and convexo-concave lenses? We dont say convexo-plane for plano-convex. Does that mean concavo-convex and convexo-concave are essentially the same?
In both types, (convexo-concave or concavo-convex) the lens has one convex and one concave side.
Convexo-concave : The concave face has a greater degree of curvature than the convex face.
Concavo-convex : The convex face has a greater degree of curvature than the concave face.
The images are as follows:
Now a days these lenses are referred as convex-concave or meniscus. It is this type of lens that is most commonly used in corrective lenses.
Convex-concave (meniscus) lenses can be either positive or negative, depending on the relative curvatures of the two surfaces. A negative meniscus lens has a steeper concave surface and will be thinner at the centre than at the periphery. Conversely, a positive meniscus lens has a steeper convex surface and will be thicker at the centre than at the periphery.