White-light Phase Shifting Interferometry for Three Dimension Surface Measurement

• Main Authors: Wen-Ming Hong, 洪文明
• Other Authors: Mao-Hong Lu
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/93134633335835686657

碩士 === 國立交通大學 === 光電工程所 === 91 === In order to study the application of white-light phase-shifting interferometry (PSI) in three dimension surface measurement ,we use traditional PZT phase shifting and achromatic phase shifting .We compare and discuss the results from both the phase-shifting methods. The measurement system is a Linnik interferometer. The light source is a halogen lamp,which is a polychromatic light source,covering the visible spectral range . In the theory we assume that the polychromatic light source has a Gaussian power spectral density, so we use a narrow bandwidth filter with central wavelength 629.5nm and broad bandwidth filter with central wavelength 550nm, to satisfy the theoretical requirement. To verify our measurement results,we compare the surface profiles measured by our interferometer with that by Zygo instrument. By using phase shifting, we can achieve high vertical resolution, but have a limited vertical depth. If we consider the characteristics of the short coherence length of white-light and make a vertical scanning to find the location of maximum intensity, we can greatly improve the measurement of vertical range.