Development of Verification Equipment for Phoropters

To solve the verification of the phoropters, optoelectronic equipment for measuring spherical vertex power, cylinder vertex power, axis position, and the center error of refractor heads based on the self-collimation sharpness method was developed. The equipment uses a grating length sensor to achieve precision measurement of concave reflector displacement, an angle encoder to measure the angular of the cross-line reticle, a CCD to achieve image acquisition, and a computer to achieve analysis and measurement. In this paper, the factors affecting the measurement accuracy and range are analyzed, the optical system of the comprehensive optometer and the key objective lens is designed, the photoelectric parameters are given, and the equipment is traceable to the national primary standard of vertex power. Theoretical analysis and experimental results indicate that the expanded uncertainly for phoropters can reach (0.03~0.08) m^-1(k=2), which meets the verification demand for the phoropters.