Polygon microlens array design and fabrication using thermal pressing in LIGA-like process

This paper describes a simple and inexpensive technique to design and fabricate polygon microlens array using thermal pressing technique. Polygon microlens array molds were fabricated by using lithography and electroforming process. Microlens pattern was designed on a photomask and transferred to a substrate through photoresist patterning. The electroforming technology was used to convert the photoresist microlens patterns into metallic molds. A hot pressing machine was used to replicate microlens array in PC substrate. The compression pressure, temperature, and pressing time were key parameters to design and manufacture microlens array. The optical properties of these microlenses have been characterized by measuring their focal lengths. The average cylindrical microlenses radii of curvature were 315μm~420μm and the average sag heights were 2.98μm~4.03μm.

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