Large-area and high-resolution distortion measurement based on moire fringe method for hot embossing process

A moiré fringe approach is developed to identify simultaneously the global and local distortions in hot-embossed polymeric samples. A square grid pattern with a pitch of 63.5 μm is hot-embossed on the polymer substrate. When a reference grid, a polymeric film with the same pattern, is placed on top...

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Bibliographic Details
Main Authors: Boning, Duane S., Taylor, Hayden Kingsley, Youcef-Toumi, Kamal, Xu, Zhiguang, Yoon, Soon Fatt
Other Authors: Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Format: Article
Language:en_US
Published: Optical Society of America 2012
Online Access:http://hdl.handle.net/1721.1/71162
https://orcid.org/0000-0002-0417-445X
Description
Summary:A moiré fringe approach is developed to identify simultaneously the global and local distortions in hot-embossed polymeric samples. A square grid pattern with a pitch of 63.5 μm is hot-embossed on the polymer substrate. When a reference grid, a polymeric film with the same pattern, is placed on top of the sample, a moiré fringe pattern is observed and recorded by a document scanner. The deviation of the intersections of the fringes from their ideal positions presents the residual distortion in the sample. With different sample-reference rotation angles eight images are acquired for the same sample to achieve the optimal result by a data fitting technique. The validity of this method is proved by the self-consistency of the results from the eight images. To the best of our knowledge, this is the first time distortion quantification has been achieved both in a large area up to that of a scanner and with a high resolution at the level of 1 μm. Furthermore, we do not use any expensive instrument, nor need to measure the sample–reference rotation angle or position the sample precisely, and the process is run automatically by a computer instead of manual operation.