Flatness Measurement System using Fizeau Type Solid Interferometer with High Speed Acquiring Multi-phase Interferograms and Highly Effective Error Decreasing Algorithm

For the purpose of achieving high accurate and high speed flatness measurement, a new interferometer acquiring M ulti- P hase interferograms using Two orthogonally polarized lights has been developed (hereafter referred to as MP2 interferometer). In this interferometer, the characteristic errors occur because three interferograms are acquired by dividing a measuring light into three. Therefore, we propose a new algorithm by which the native errors of this interferometer are surprisingly decreased.