Patent ID: 8797520

Claim:
A wavefront aberration measuring apparatus which measures a wavefront aberration of an optical system to be inspected without using an interference method, the wavefront aberration measuring apparatus comprising: a point light source configured to supply a measuring light; a photodetector comprising a detection surface arranged at a position optically conjugate with the point light source, the photodetector being configured to measure a light intensity of a spot light formed on the detection surface; a wavefront change applying section arranged in an optical path between the point light source and the photodetector, the wavefront change applying section being configured to apply a wavefront change to the light outcome from the optical system based on an output of the photodetector so that the light intensity which is measured by the photodetector is maximized; and a measuring section configured to measure the wavefront aberration of the optical system, without using the interference method, based on the output of the photodetector and the wavefront change applied by the wavefront change applying section, wherein the optical system is arranged with respect to the point light source such that the light outcome from the optical system into the wavefront change applying section as a parallel light.