| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a calibration method for calibrating a geometrical error of a surface shape of a reference mirror using a reference device whose geometrical error of the surface shape is unknown.SOLUTION: The interferometer comprises a reference mirror 33 whose geometrical error of the surface shape is unknown and which is for generating interference light between the measurement object surface and it. A reference device WO whose geometrical error of the surface shape is unknown is disposed at a position of the measurement object. While parts of the measurement regions are overlapped, the reference mirror 33 is moved to scan so as to measure the surface shapes of a plurality of regions in each of a plurality of directions. With respect to each measurement region, the geometrical error of the surface shape of the reference mirror 33, the geometrical error of the surface shape of the reference device (center portion WOC), and the equation established between surface shape measurement values are solved to obtain the geometrical error of the surface shape of the reference mirror 33.</p> |
