Research On Surface Divergence Topograph Of Progressive Multifocal Lens

With the development of optical technology, Complex refractive distribution of optical lenses have been emerging on the market. The traditional single point measurement has been unable to achieve one time measurement of the entire optical lens. At present, the rapid testing of the surface refractive power of the entire glasses is one of the hot spots in the test technology. Using Talbot interferometry for measurement of progressive multifocal lens diopter has been a way to solve this problem for its high precision, simple optical path.The basic theory of progressive multifocal lenses based on Talbot-Moire fringes is analyzed. The relationship between the diopter and the system parameters, which included the angle, spacing of the two gratings and Moire fringes angle, is established. The formula is optimized to solve the problem of grating line is not easy to determine. The system parameters are designed based on moire fringes analog. And to improve the quality of moire fringes, the simulation of different parameters is carried out. The three different gate integrated measurement method not only can complete the measurement of the degree of 0° to 800° of the manufacturer’s requirements. The measurement effectively solve the problem of sensitivity reducing. In view of the displacement of the measurement information, the position correction algorithm is proposed, which can effectively solve the defect of the refractive error of the lens. And for the generation of the curved moire fringes, the piecewise fringes fitting method is proposed. This method not only can complete the slope of arbitrary bending fringes, but also has a fast processing speed in the actual measurement. The model of the experimental system is built, and the software is written by VS2013 and MATLAB. The results show that the accuracy of the progressive multifocal lenses of -200 and -100 can reach 3.1%. The measuring device meets the requirements of the national spectacle lenses, and the whole measuring system has good stability.