# Radius of curvature requirement in optical drawings

Published on by Sergey Sidorovich. Source.

One of the key parameters found in optical drawings based on ISO 10110 standard.is the  radius of curvature of lens surfaces. This parameter can be found at first line of the surfaces columns in table of parameters. You can click here to review.

Optical properties of the lens are defined by the shapes of its surfaces, usually these surfaces are spherical. This means that lens surface is part of the some sphere surface.

Look at the picture above. You can see that lenses surfaces shapes coincide with sphere surface shape. Value of the sphere radius is the value of lens surface radius of curvature. Optical Engineers specify this value for each surface of the lenses in drawings.

In short, lens surface radius of curvature is the radius of the sphere which forms this surface. Radius of curvature value is value of sphere radius.

Attentively look on table of parameters in  this article. You can see literal mark near the radius curvature value. You can find two types of literal marks in optical drawings of the lens. These marks indicate what kind of the surface lens should be produced – Convex (CX) orConcave (CC).

We should note that radius of curvature is a basic parameter of the lens. This parameter defines focal power of the lens (in other words effective focal length). Mistakes in this value can have substantially negative influence on optical system.