METHOD AND DEVICE FOR MEASURING SHAPE OF CURVED SURFACE

摘要

PROBLEM TO BE SOLVED: To provide a method and device for measuring the shape of a specific frequency band as a surface which substantially affects optical characteristics without using a means for creating a highly accurate reference wave front such as a diffraction optical element even on an arbitrary free curved surface. SOLUTION: A surface to be inspected 3 is irradiated with coherent light. The wave front of a part of a spatial frequency band among a reflected wave front from the surface to be inspected 3 is optically extracted. Interference fringes are created from the reflected wave front from the surface to be inspected 3 and the extracted wave front. Information on the shape of the specific frequency band of the surface to be inspected 3 or information on surface accuracy is obtained from the interference fringes.