Fabrication of high fill-factor aspheric microlens array by digital maskless lithography

A simple and effective method for fabricating high fill-factor aspheric microlens array using digital maskless lithography is reported. The method use the contour planes of the designed profile as binary image, which replace physical mask by DMD display. On the lithography system, the dose accumulated over multiple exposures and the exposure dose reconstructed in wafer, then the designed profile developed. Aspheric microlens arrays with hexagonal base and square base were produced by the method, and they were gapless at each microlens periphery, so the microlens array with fill-factor of 100%.