Moiré techniques based on memory function of laser scanning microscope for deformation measurement at micron/submicron scales

This paper presents two up-to-date moiré techniques for deformation measurement based on the memory function of a laser scanning microscope (LSM). The two techniques are the LSM overlapping moiré method and the LSM secondary moiré method. The formation principles and the measurement principles of these two methods are presented and compared to those of the traditional scanning moiré method for the first time. The applicable conditions and characteristics of these three moiré techniques are analyzed. Some typical moiré fringes on a strain gauge, carbon fiber reinforced plastics, a polyimide film, and a silicon wafer are illustrated. Our proposed LSM overlapping moiré method and LSM secondary moiré method are able to expand the application range of the LSM in deformation measurement to the micron and the submicron scales.