Measurement of paraboloid surface workpiece with zero error sum

According to the existed method of positioning paraboloid surface workpiece for measuring its shape accuracy, this paper proposes a new method of positioning paraboloid surface workpiece with zero error sums. The key idea of new method is to consider whole workpiece surface comprehensively, which can appreciate whole workpiece surface reasonably, objectively and entirely. It is different from former measuring methods mainly considering several points with big errors. The new method is important for elements used in a optical system, since in optical system the main factors of affecting optical system characteristic are not only several points with big errors on optical element surface, but also the whole surface. It is favorable to improve workpiece surface shape accuracy and its optical characteristics. Its principle not only can be used in measuring paraboloid but also for measuring other aspheric surface.