Simulated enhancement of the axial symmetry of a micro lens array with a modified mask by using an excimer laser dragging process

Abstract

This computer simulation investigated the fabrication of an aspheric micro lens array by using a laser dragging process. An excimer laser dragging process is capable of manufacturing a microstructure array with a curved surface. Generally, a mask of quadratic equation form (like a semi-circle) is adopted in the dragging process to produce a micro lens array. However, by adopting a semi-circular, elliptical or hyperbolic shape of mask, the axial symmetry in the border region of a micro lens is not good. The unsatisfactory form accuracy limits the use of dragging in practical optical applications. Newly modified shapes of masks were computer-simulated to solve this problem. In order to remove the inaccurate region from a single micro lens, an original mask was trimmed both sides of the boundary parts to produce a new mask. For all these three kinds of mask, the simulated results demonstrate that this new method can generate a better axial symmetry and higher fill factor than the untrimmed ones.