Research On Measuring Method Of Curvature Radius Of Plano-Convex Lens With Stress Calibration

Newton's ring is a typical equal-thickness interference phenomenon.One of its basic applications is to measure the radius of curvature of a plano-convex lens.However,due to the existence of stress between the plano-convex lens and the optical flat glass in the Newton ring device,the measurement error of the curvature radius of the plano-convex lens is caused.Partially large.In view of the above problems,the first is to propose and design a Newtonian ring image observation and measurement system based on mobile phone observation to solve the problem that the long-time artificial observation reading microscope is easy to cause eye fatigue.By comparing the measurement results of the observation measurement system and The measurement results of the manual measurement method prove that the observation and observation system is clear and intuitive,and can reduce the measurement error.Secondly,theoretically,based on contact mechanics,the contact stress deformation caused by Newton s ring is used.A small variation of the dark spot in the center of Newton's ring interference pattern is proposed.A Newtonian ring center stress measurement method based on contact mechanics is proposed.The theoretical relationship between the central stress of Newton's ring and the dark spot of Newton's ring is derived.The transformation relationship between applied stress and central dark spot is experimentally studied by using the Newton ring device.It is proved by theoretical analysis and experimental measurement.The feasibility of measuring the central stress of Newton's ring by measuring the size of the dark spot in the center of Newton's ring by contact mechanics is compared with the method of measuring the Newton's ring stress based on the plate theory.The stress is measured when the stress is greater than 13N.The relative error of the measurement results is less than 2.8%.Thirdly,the measurement error caused by the stress between the plano-convex lens and the optical flat glass in the Newton ring measuring device is large.A method for measuring the radius of curvature of the plano-convex lens based on stress calibration is proposed.The relationship between the experimental calibration stress and the radius of curvature of the lens is obtained by data fitting.The fitting function relationship between the radius of curvature of the lens and the central stress of Newton's ring is obtained.The fitting formula is used to calibrate and measure the radius of curvature of the lens under different stress conditions.,thereby eliminating or reducing the effect of stress on the measurement results,and The experimental verification shows that the relative error of the experimentally measured plano-curvature radius curvature radius calibration measurement and the nominal value of the plano-convex lens curvature radius is less than 1.9%in the range of 1?206N center stress,which proves the feasibility of the method.The fourth is to study the Newton ring measurement by image processing method,and write the MFC-based CMOS camera monitoring and photographing application program.The CMOS camera is used to capture the Newton ring light interference image and image processing to measure the Newtonian ring interference image center dark spot.Radius,automatic calibration measurement of the radius of curvature of the plano-convex lens,and experimental verification,repeated experiments,the relative error of the experimental calibration results and the nominal value of the curvature of the plano-convex lens is less than 1.7%,which proves that the automatic calibration measurement application is practical.value.