Method for detecting large-caliber aspheric optical element by utilizing three-coordinate measuring machine

Abstract

The invention relates to a method for detecting a large-caliber aspheric optical element by utilizing a three-coordinate measuring machine, which comprises the following steps of: processing the data obtained by the three-coordinate measuring machine by utilizing an information processing technology, carrying out error compensation on the measuring head of the three-coordinate measuring machine by adopting a method for compensation by utilizing the measuring head, eliminating the tilting and translation errors of detected data by utilizing a least square method, eliminating the constant term and the tilting term after surface shape data Zernike polynomial fitting by a Gram-Schmidt orthogonalization method, and restoring the surface shape of the detected large-caliber aspheric optical element to realize the purpose of high-precision three-coordinate measurement of the large-caliber optical element. The invention comprehensively considers the error source of the three-coordinate measuring machine of the detected large-caliber aspheric optical element, so that the surface shape quality of the optical element can be more truly and objectively evaluated. The invention is used for processing the surface shape measurement error of the optical element by adopting the measuring-head compensation and least square methods and has important application value for the surface shape detection of the high-precision large-caliber optical element.

Description

technical field [0001] The invention belongs to the field of optical testing, and relates to an improvement on the surface error processing method of the large-diameter aspheric optical element, especially on the surface contact measurement error of the optical element. Background technique [0002] The manufacturing process of large aspheric optical components can generally be divided into workpiece forming, grinding, and polishing. Each processing stage has its corresponding surface shape detection method as a processing guide. The amount of material removed in the polishing stage is very small. At the same time, since the vertex curvature radius and eccentricity of the processed surface are basically not changed during polishing, the vertex curvature radius and eccentricity of the surface must be strictly controlled during the grinding stage. Therefore, the detection technology in the grinding stage is the key to the processing technology of large aspheric optical compone...

AI Technical Summary

Problems solved by technology

However, this method needs to use a standard plane mirror to realize surface shape detection by self-calibration method, or use a compensator that matches the aspheric surface to be tested to realize surface shape detection. Therefore, the disadvantages of the above detection method are: difficulty, high cost, long cycle

However, the probe of the three-coordinate measuring machine is not an ideal measuring point, but a probe with a certain radius, so the error caused by the radius of the probe will be brought during the measurement; at the same time, with the measurement stroke The increase will also introduce a certain stroke accumulation error

Therefore, the system error of the above-mentioned three-coordinate measuring machine will definitely affect the detection accuracy of optical components

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