Fabrication of continuous relief micro-optic elements using real-time maskless lithography technique based on DMD

• The required dose distribution of the design profile is calculated.
• The contour planes of the profile of the required exposure dose as virtual masks.
• The dose accumulated and the required exposure dose is reconstructed on the systems.
• Arbitrary continuous relief micro-optic elements can be obtained.

A novel method is proposed to fabricate continuous relief micro-optic elements using real-time maskless lithography technique based on digital mirror device (DMD). To evaluate the method, aspheric and spheric micro-lens array was fabricated by following the proposed principle. Firstly distribution of the required exposure dose of lens array was obtained and sliced into a number of contours of equal proportions. Then the contour planes instead of virtual masks were converted into binary image. On the lithography system, the dose accumulated over multiple exposures and the required exposure dose profiles were reconstructed. Finally in the photoresist layer, virtual profiles of lens array were formed, consistent with the original designed elements. The method is feasible and reliable for the fabrication of arbitrary continuous relief micro-optic elements.