Study On Aspheric Surface Measurement Using Coordinate Contour Measuring Machine

Aspheric surface, which have the deviation with spherical surface, are being usedwidely in various optical systems. Compared with spherical surface, aspherics have a seriesof advantages, such as improve image quality, correct aberration, expand field of view,increase the effective distance and make the optical system compact, lightweight. Off-axisaspheric system as one of the aspheric optical systems is not only able to improve systemresolution, expand viewing angle, but also to further reduce the size and weight of opticalsystem. Especially, with the rapid development of space optics, space sensor resolution isrequired higher and viewing angle is required larger. Off-axis aspheric surface will becomeone of the essential components in the optical system.However, in recent years, the hysteresis of aspheric detection level has increasinglybecome one of the important factors which are restricting the aspheric development.Although there are many aspheric detection methods, all these methods exist differentlimitations. Aim to the measurement of aspheric surface, especially off-axis asphericsurface, this paper discusses the method for testing aspheric surface with coordinatecontour measuring machine (CMM), the main work we did is as follows:1. Some common methods for testing aspheric surface were introduced; the previous ideasand methods of testing aspheric surface with three-coordinate contour measuringmachine were summarized.2. The principle of testing aspheric surface using CMM were detailed analyzed. And onthis basis, the reasons for the formation of errors in the aspheric surface detectionprocess and their impact on the measurement results were analyzed.3. An appropriate mathematical method that can solve the error value in the practical application was selected. And then the error correction model for testing asphericsurface with CMM was established. Both axis-symmetric and off-axis aspheric surfacemeasurement data are applied to the model.4. The relevant programs were compiled by the combination of matlab and c language. Thefeasibility and accuracy of the model and programs have been proved through thetheoretical simulations and the experimental results of the actual aspheric surfaces. Inaddition, the program operator interface was designed by using MFC.