Assessment of replication fidelity of optical microstructures by hot embossing

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• 作者：Giuseppe A. Cirino ; Renê M. Granado…
• 关键词：Diamond turning ; Hot embossing ; Diffractive optics ; Wavefront sensor ; PMMA replication fidelity ; Aspheric Fresnel lens
• 刊名：The International Journal of Advanced Manufacturing Technology
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：88
• 期：1-4
• 页码：303-316
• 全文大小：
• 刊物类别：Engineering
• 刊物主题：Industrial and Production Engineering; Media Management; Mechanical Engineering; Computer-Aided Engineering (CAD, CAE) and Design;
• 出版者：Springer London
• ISSN：1433-3015
• 卷排序：88

文摘

This work reports the performance evaluation of low-cost hot embossing processes of fine three-dimensional microstructures, namely (i) cylindrical microlens array, (ii) plano-convex aspheric Fresnel lens, and (iii) pyramidal array structures. All those optical elements were replicated by employing a low-cost hot embossing tool in optical quality acrylic material. Scanning electron microscopy and optical interference microscopy techniques were used to quantitatively measure the obtained structures. In terms of the replication fidelity with respect to the mold counterpart, the resulting optical elements presented at least 96 % of dimensional fidelity at micro- and nanometer scale, including the structures with sharp edges present in the Fresnel lens. In terms of the surface optical quality, resulting root mean square surface roughness of at least one tenth of wavelength was obtained, considering applications in the visible range of spectrum. The results showed that even nanostructures generated by the material removal mechanisms during mold fabrication, such as crystal grain elastic recovery, were well replicated with differences in the range of few of nanometers which is within the vertical resolution of the employed optical interference technique.