METHOD FOR THE ABSOLUTE MEASUREMENT OF THE FLATNESS OF THE SURFACES OF OPTICAL ELEMENTS

摘要

A method for absolute measurement of flatness of surfaces of optical elements. In the method, an interferometer having a measurement axis is used for applying a three-flat method by three optical elements, by conducting actual measurements on the elements, and planes of the elements are reconstructed by an iterative processing operation in which measurements are simulated and simulated measurements are compared with the actual measurements. At least two actual measurements are made after having performed a rotation around the measurement axis and/or a translation perpendicularly to the measured axis, of a measured optical element relatively to the other.