| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface shape measuring device capable of measuring highly accurately the surface shape of an optical element or the like such as a lens, a mirror or the like, and a wave front aberration measuring device capable of measuring highly accurately wave front aberration of a projection lens. SOLUTION: In this surface shape measuring device, a measuring beam reflected by an inspection surface which is a part of light emitted from a light source is allowed to interfere mutually with a reference beam having a reference wave front which is the other part of light emitted from the light source, and the state of an interference fringe generated by the interference is detected, to thereby measure the surface shape of the inspection surface. The measuring device is equipped with a mechanism for changing phases of the reference beam and the measuring beam relative to some standard in the device, and a mechanism for detecting each phase difference in the phase states of the plural reference beams and the measuring beams changed based on the phase changing mechanism and calculating the mean value of each phase difference information.
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