Research on digital coding mask technique for the fabrication of binary optical element

Digital coding mask technique is proposed to fabricate binary optical element (BOE) in this paper. Digital coding mask technique is to input the designed mask by coding into the digital micro-mirror device (DMD), and DMD is controlled real-timely by computer, so the mask patterns can be controlled real-timely as well. Then the mask imaging on the substrate spreading with photoresist by final minification and projection, then through the process of development, fixation and photoetching, BOE can be fabricated. Coding is achieved by computer-generated hologram coding and its improved methods. The digital coding-mask technique can give full advantage of DMD's real-time, flexible and easy for alignment to mask fabrication which needs photoetching for more times. In addition, the flexibility of improved algorithm, the digital coding mask technique is helpful to solve mask aberration problem, which is caused by no-linear effect in the process of projection and exposal system, and the technique can also make use of optimization algorithm to noise reduction processing, thus the photoetching quality can be improved.