Open AccessShape-controlled, high fill-factor microlens arrays fabricated by a 3D diffuser lithography and plastic replication method
Author(s) -
Sun Hyok Chang,
JunBo Yoon
Publication year - 2004
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/opex.12.006366
Subject(s) - microlens , materials science , polydimethylsiloxane , optics , photoresist , lithography , diffuser (optics) , replication (statistics) , fabrication , focal length , optoelectronics , mold , lens (geology) , photolithography , resist , soft lithography , ultraviolet , uv curing , curing (chemistry) , nanotechnology , composite material , medicine , light source , statistics , physics , mathematics , alternative medicine , layer (electronics) , pathology
This paper describes a simple and effective method to fabricate a plastic microlens array with controllable shape and high fill-factor, which utilizes the conventional lithography and plastic replication. The only difference from conventional lithography is the insertion of a diffuser that randomizes paths of the incident ultraviolet (UV) light to form lens-like 3D latent image in a thick positive photoresist. After replication of the developed concave microlens mold onto the polydimethylsiloxane (PDMS), the focal length of the fabricated hemispherical microlens was observed to be 13-88 microm depending on the UV exposure dose. Two PDMS curing conditions were tested, where the elevated temperature of 85 masculineC resulted in smoother surface roughness of 2.6 nm in RMS value in the microlens mold. The proposed method can be extensively applied for microlens fabrication with other plastic materials due to its simplicity and versatility.