ANALYSIS OF EXCIMER LASER MACHINING OF MICROPATTERNS

A laser dragging process to ablate a groove pattern and more sophisticated 3D features on a polycarbonate (PC) sheet through a shape of mask opening is analyzed. To predict the machined profile during the dragging process, a mathematical model describing the relationship between laser machining parameters and the produced profile is developed. The proposed model is verified experimentally. This study depicts the results of the experiment and numerical simulation in both single and cross dragging using elliptic, triangular and rectangular masks. The operating parameters include the dragging velocity, pulse repetition rate, pulse number, fluence and the opening dimension of the mask pattern. A good agreement between the experiment and simulation with deviation less than 14% is demonstrated. Based on the proposed model, miniature lamp lens can be manufactured by varying laser operating parameters, mask shape and dimensions. Further, the advantage of the micro-size lamp lens on light efficiency is explored. The results illustrate the optical systems with the micro-feature lamp lens can offer better optical performance than those with macro-feature lamp lens.