Patent ID: 8891077
Filing Date: 2014-11-18
Classification: G01J

Abstract:
1. A wavefront measuring method of measuring a wavefront of a target optical system using a Shack-Hartmann sensor having a micro lens array and a plurality of light receiving elements, the micro lens array having a two-dimensional arrangement and including a plurality of micro lenses configured to condense light that has passed the target optical system upon the light receiving elements, the wavefront measuring method being performed by a processor and comprising the steps of: provisionally determining one of the plurality of light receiving elements as a center-of-gravity position in a spot having a light intensity distribution of light condensed on the light receiving element; calculating a distance between the provisionally determined center-of-gravity position and an adjacent center-of-gravity position; setting an area smaller than and inside of a spot that partially overlaps another spot, and setting a spot that does not overlap another spot to the area; calculating a center-of-gravity position for each area; and calculating the wavefront based upon a shift amount between an ideal center-of-gravity position when parallel light enters the micro lens array and the center-of-gravity position of each area.