A numerical simulation of mask shape effect for fabrication of hexagonal microlens array by using excimer laser dragging process

Abstract

This investigation analysed the characteristics of simulating the fabrication of an aspheric hexagonal microlens array using a laser dragging process. Traditionally, an aspheric microlens array with rectangular coordinates was produced using an excimer laser dragging process. For the hexagonal case, the first step in the proposed dragging process is to generate microchannels with a cross-section shape similar to the mask. Then, the dragging procedure is repeated twice, each time after rotating the work piece by 60° relative to the previous channels. This microlens array can be applied in image processing. Variously shaped masks were computer simulated. The results demonstrate that the parabolic-shaped mask can generate excellent axial symmetry for both rectangular and hexagonal microlens array. The analytical results of this study indicate that a hexagonal microlens array has a better axial symmetry than a rectangular microlens array. But for the parabolic case, a hexagonal microlens array has a smaller fill factor than a rectangular microlens array.

Acknowledgment

The author thanks the National Science Council of the Republic of China, Taiwan, for financially supporting this research under Contract NSC-94-2218-E-230-001.