The Study Of Wavelength Scanning Interference Testing Method For Aspherical Surface

With the development of technology, people have known special function of aspheric surface in kind of optical instruments little by little. So optical aspheres are more and more adopted in designing and producing of optical instruments recently. Because of the variety of aspheres and different requirements of dimension and precision, the testing of asphere is more difficult and complex than that of sphere. The surface testing of aspheric and optical part is especially difficult, which is big scale and high precision.The paper studies mainly a new kind of measure method of aspheric surface-laser wavelength-scanning interference testing. This research is aimed at putting forwarding laser wavelength scanning interference testing method. Processing and analyzing instantly-read interference pattern corresponding with continuous varying wavelength, the method overcomes the following disadvantage: the longer referenced and measuring optical circuit in big-scale high-accuracy asphere testing and the sensitive interferential system to the disturb, such as the oscillation of worktable, dithering of air, and so on.In this paper, we summarize the present testing level of optical aspheric surface, expound the principle of laser wavelength scanning interference testing method, and analyze the laser that can be tuned, and we also study the change of wavelength. Further more, we achieve the elementary design of experiment device, curtly introduce the method for interference fringe processing and image processing by Matlab. By the study of this method, we can not only solve the surface testing of big-scale high-precision aspheric surface, and advance the application of asphere, but also we can improve the integration of digital image processing, application of CCD and optical testing.