Patent ID: 8243256

Claim:
A measurement apparatus which measures an aberration of a measurement target optical system, the apparatus comprising: an optical element which is arranged on a side of an object plane of the measurement target optical system, and configured to split light from a light source into test light and reference light; a generation unit configured to generate a plurality of phase states by changing a phase difference between the test light and the reference light; a fringe scanning unit configured to perform fringe scanning by changing the phase difference between the test light and the reference light; wherein said fringe scanning unit further comprises a piezoelectric element for moving the optical element in an optical axis direction of the measurement apparatus; a detector configured to detect an interference pattern between the test light and the reference light; a determination unit configured to determine a nonlinear error representing a nonlinear relationship between control data of the piezoelectric element and a Zernike term of the aberration which is derived from the interference pattern formed in the plurality of phase states; and a correction unit configured to correct, based on the nonlinear error determined by the determination unit, an aberration calculated from the interference pattern between the test light and the reference light to obtain an aberration of the measurement target optical system.