Abstract: To seek a higher precision in manufacturing is the eternal target. The manufacturing accuracy is not only affected by the factors such as machine, tool, the numerical control technology, but affected by the accuracy of measurement system. Among many measurement technique of aspheric surface, Grating measurement technique with contact sensor has attained higher precision and been applicable to many cases. Two improvement on the technique were put forward： One is that atomic force microscope (AFM) replaced mechanical sensors to improve the measurement accuracy of aspheric surface manufacturing system, which worked in the tapping model. The other is that holographic grating replaced common grating. The properties of holographic grating technology is superior to that of common grating, and displacement-measuring technology with holographic grating is superior to displacement-measuring technology with common grating. Therefore, it is necessary to replace common grating with holographic grating to meet the need of high-precision aspheric surface measurement.

Key words: AFM, Aspheric surface, High accuracy measurement technology, Holographic grating