Patent ID: 7119907

Claim:
A low coherent interference fringe analysis method dividing low coherent light as illumination light in an interferometer apparatus into two light components, using one of thus obtained two light components as reference light, irradiating a sample with the other so as to form object light carrying phase information of said sample, and analyzing phase information of said sample according to information of interference fringes obtained by interference of said object light and said reference light with each other; said method comprising the steps of: expressing a light intensity distribution of said interference fringes along an optical axis of said interferometer apparatus in terms of a predetermined light intensity distribution function including an unknown by using a predetermined envelope function; carrying out a phase shift with a predetermined shift width so as to measure said light intensity at each shift stage; computing said unknown of said light intensity distribution function according to said measured light intensity at each shift stage; determining a peak position of a curve of said envelope function according to said computed unknown; and attaining said phase information according to thus determined peak position.