Mask-free photolithographic exposure using a matrix-addressable micropixellated AlInGaN ultraviolet light-emitting diode

We report the integration of a UV-curable polymer microlens array onto a matrix-addressable, 368-nm-wavelength, light-emitting diode device containing 64364 micropixel elements. The geometrical and optical parameters of the microlenses were carefully chosen to allow the highly divergent emission from each micropixel to be collimated into a narrow beam of about 8-mu m m diam, over a distance of more than 500 mu m. This device is demonstrated as a photolithographic exposure tool, where the pattern-programmable array plays the role both of light source and photomask. A simple pattern comprised of two disks having 16-mu m diam and 30-mu m spacing was transferred into an i-line photoresist. (c) 2005 American Institute of Physics.