Fabrication of plastic microlens array using gas-assisted micro-hot-embossing with a silicon mold

This paper reports an innovative method for fabrication of plastic microlens arrays. By using gas pressure to press the plastic film onto silicon mold of holes array, microlens array can be directly fabricated. A machine with closed chamber for gas-assisted micro-hot-embossing was constructed and tested. The 300 × 300 plastic microlens array with a diameter of 150 μm and a pitch of 200 μm were successfully produced. Under the condition of 150 °C, 10–40 kgf/cm2 gas pressure and 30–90 s duration, the microlens with uniform and strong focusing function were formed on the polycarbonate film. The shape and height of microlens can be changed by adjusting the processing temperature, pressure and duration. This technique shows great potential for fabricating microlens array on large plastic films with high productivity and low cost.