Imprinting of double-sided microstructures with rapid induction heating and gas-assisted pressuring

Many components need microstructures on both upper and lower surfaces for integrating and enhancing functions. For the replication of microstructures on the polymeric substrate, hot embossing is an inexpensive and flexible method. However, the cycle time is too long and the embossing pressure is not uniform. This study is devoted to developing an innovative hot embossing system, which integrates induction heating and gas-assisted pressuring for the imprinting of double-sided microstructures. In this study, a wrapped coil for induction heating was designed, implemented, and tested. Then, an apparatus with wrapped coils for induction heating and gas pressuring for hot embossing was designed and constructed in a chamber. Experiments showed that the cycle time can be reduced to 4 min. V-cut patterns and microlens array had been successfully replicated on both surfaces of the polycarbonate substrates. The replication rates were above 95%. This study proves the potential of induction heating gas-assisted embossing for rapid replication of double-sided microstructures for industrial applications. (paper)