SHAPE CALCULATION METHOD

PROBLEM TO BE SOLVED: To accurately calculate a high frequency component of a to-be-inspected surface in an aspheric surface shape calculation. SOLUTION: A shape calculation method includes: a process for dividing the to-be-inspected aspheric surface into a plurality of measurement regions so as to have overlapped regions, receiving an interference pattern due to an interference light generated by a light reflected by a reference surface as a reference for calculating a shape of the to-be-inspected surface and a light reflected by the measurement region at a light receiving section, and calculating the shape of each measurement region; and a process for splicing the shape calculated in each measurement region, and calculating the shape of the to-be-inspected surface. The process for calculating the shape of each measurement region includes: a process for adjusting a relative position between the to-be-inspected surface and the reference surface so as to minimize the number of lines measured in the interference pattern; a process for adjusting a position of the light receiving section so as to maintain a conjugate relationship between the to-be-inspected surface and a front light section while the position of the to-be-inspected surface is adjusted; a process for measuring a phase distribution of the interference pattern while the position of the light receiving section is adjusted; and a process for calculating the shape of the measurement region by using the measured phase distribution. COPYRIGHT: (C)2010,JPO&INPIT