Microlens array based three-dimensional light field projection and possible applications in photolithography

摘要

A three-dimensional (3D) system is developed with a microlens array (MLA) and a digital micromirror device (DMD)type spatial light modulator (SLM) to perform light field projection. In order to get 3D projections, a pixel value map, i.e.elemental images, is required to be loaded into SLM. Algorithm to render elemental images is developed in this studyusing ray tracing. The reconstructed 3D projection, which is the 3D output of the system, is examined by cameras atdifferent focal positions. The result shows that the intended projection patterns are correctly reconstructed. The light fieldprojection method can be extended to photolithography when photoresist is exposed to reveal the 3D structures of theintended projection. Compared with current 3D lithography, the proposed MLA based projection/lithography canreconstruct micro-structure with 3D curved structures in a single projection, which can significantly improve the 3Dfabrication speed and quality. With the future implementation of optical compression and femtosecond laser, the proposedtechnique has the capability of conduct large area microfabrication with resolutions better than diffraction limit at a veryhigh speed.