A Simulation Study on Figure Error Correction Using Near-Gaussian Removal Function in Numerical Controlled Local Wet Etching
Local wet etching (LWE) is a non-conventional deterministic surface figuring and finishing technique in ultra-precision optics fabrication fields. The general removal function in LWE is cylinder, so fringe of the removal function is sharp and scale of the removal function is determined by inner diameter of the nozzle head. When fabricating some specimen with high frequency figure error, ideal designed shape can’t be achieved easily. Compared with general LWE removal function, Gaussian removal function is more suitable for figuring owing to its smoother fringe and the centralization of its energy. At the same time Gaussian removal function can improve the efficiency in calculation of the dwelling time, because it’s very suitable for Fourier transform. What’s more, theoretical residual figure error can also be reduced for Gaussian removal function’s high spatial resolution. Ideal Gaussian function is difficult to obtain in LWE, so we have proposed near-Gaussian removal function by eccentric rotation of the nozzle head. Through controlling offset of the eccentric rotation, we achieve the optimal near-Gaussian removal function in LWE. Aims of the introduction of near-Gaussian removal function in LWE are to improve the fabrication efficiency and to remove the surface’s high frequency residual figure error.
Tojiro Aoyama, Hideki Aoyama, Atsushi Matsubara, Hayato Yoshioka and Libo Zhou
X. M. Shen et al., "A Simulation Study on Figure Error Correction Using Near-Gaussian Removal Function in Numerical Controlled Local Wet Etching", Key Engineering Materials, Vols. 523-524, pp. 276-280, 2012