Spherometer

A ring spherometer is a measuring device for determining the radii of curvature of spherical lenses. It consists essentially of a flat hollow cylinder on which the lens may be placed centrally. At the center of the hollow cylinder is a sensor that allows the reduction or curvature can be determined relative to the zero position. The zero position can be adjusted by placing a plane-parallel plate on the Spherometers and the probe calibrated it.

From the measured reduction or curvature T and the inner or outer diameter of ring D can be calculated the radius of curvature. The following applies according to the Pythagorean theorem:

• Optical measuring device