Fabrication of precision micrograting on resin substrate utilizing ultrasonic-assisted molding

Molding is an effective and efficient approach to producing highly functional optical elements with complex shapes. However, edge sharpness is a serious problem with molded microstructures. An Ultrasonic- Assisted Molding (UAM) device was developed to improve shape transferability. First, basic experiments showed that UAM induced a maximum temperature increase of 3.2°C for a polycarbonate substrate with a starting temperature of 170°C, 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, micrograting was fabricated using UAM and conventional molding, and the UAMmicrograting had better transferability with a 30-smolding time. Therefore, UAM may be an effective process for reducing molding time.