Method of evaluating inhibition of CCOS (computer controlled optical surfacing) process on errors under different frequencies

Abstract

The invention relates to a method of evaluating the inhibition of CCOS (computer controlled optical surfacing) process on errors under different frequencies. The method includes the steps of S1, building a formula (1), PSDaft=(1-H)(1-H)<*>*PSDbef, for smoothing spectral function H, PSDaft and PSDbef according to the power spectral density functions PSDbef and PSDaft before and after optical element polishing, with (1-H)<*> being a conjugate to (1-H) and the symbol * being an operator used for obtaining the conjugate; S2, subjecting the formula (1) to bilateral modulo operation according to complex operation algorithms to obtain a power spectral density function expression (2), PSDaft=|(1-H)|2*PSDbef, for polished surface shape data; S3, solving the formula (2) according to |H|<1 due to the fact that the smoothing spectral function H is for Fourier transform after function normalization is removed, thus establishing a smoothing spectral function H formula (3); expressing the inhibition of the PCCOS process on errors under different frequencies as a frequency normalization function, calculating smoothing spectral function curves according to the PSDbef and PSDaft obtained before and after polishing, and evaluating the magnitude of the inhibition of the CCOS process on the errors under different frequencies according to values of the smoothing spectral function curves.

Description

technical field [0001] The invention belongs to the technical field of optical precision detection, and in particular relates to an evaluation method for the ability of CCOS polishing technology to suppress errors in different frequency bands. Background technique [0002] In high-precision optical systems, the influence of errors in different frequency bands on the surface of optical components on the performance of the optical system has attracted more and more attention. Low-frequency errors distort the image of the imaging system and introduce various aberrations; intermediate-frequency errors cause light to scatter at small angles. As a result, flares are generated in the imaging, which affects the contrast of the image; high-frequency errors cause light to scatter at a large angle and reduce the reflectivity of the mirror; therefore, it is particularly important to control the surface manufacturing errors of optical components by frequency division. For low-frequency s...

AI Technical Summary

Problems solved by technology

For low-frequency surface errors, Zernike polynomials, PV values ​​and RMS values ​​can be used to accurately describe them, and they can be eliminated by controlling the dwell time of the local area of ​​CCOS processing technology. However, the above methods are difficult to apply to small-scale medium-high frequency errors

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