Abstract
Molding is an effective and efficient approach for producing highly functional optical elements with complex shapes. However, edge sharpness is a serious problem with molded microstructures. Ultrasonic assistance can induce heat generation and reduce friction during the molding process, and therefore, an ultrasonic-assisted molding (UAM) device was developed to improve shape transferability and demolding performance. First, basic experiments showed that UAM induced a maximum temperature increase of 3.2℃ for a polycarbonate substrate with a starting temperature of 170℃, and the stick-slip phenomenon was not observed with ultrasonic vibration. Second, UAM and conventional molding simulation models were constructed to compare the transferability of a microgroove; ultrasonic superimposed press movement demonstrated the highest transferability. Finally, microgratings were fabricated using UAM and conventional molding, and the UAM micrograting had better transferability with a 30-s molding time. Therefore, UAM may be an effective process for reducing molding time.
