Back-vertex-power measurement system based on laser differential confocal technique

A new vertex-power measurement method based on laser differential confocal technique is proposed for the demand of high-precision back-vertex-power measurement. A vertex power measurement system is built up. This system takes advantage of outstanding focusing ability of laser differential confocal system to improve the positioning accuracy, and uses the interferometer to measure the distance from the origin and finally gets the results by means of conversion of the formula. The component design specifications and influence factors are analyzed. Theoretical analysis and experimental results show that the measurement error of the method is about 0.03 m^-1.