Fabrication of refractive microlens array by etching dichromate gelatin with enzyme solution

A new method is developed to fabricate a refractive microlens array by etch ing ammonium dichromate gelatin (ADG) with enzyme solution. The light expos es ADG through a high contrast binary mask, then the exposed parts of ADG g enerate a cross-linking reaction. Usually, the relief achieved by water dev eloping is very shallow (<1 <mu>m), so we compound a 0.2% concentration pro tein enzyme solution as the developer to develop ADG and deepen its relief. At 37 degreesC, the biochemical reaction occurs between ADG and the enzyme solution, and because of surface ens on, ADG turns to spherical structure after developing. The optimum y technique parameters of this process are pr esented. The principle of etching ADG with an enzyme solution to achieve de ep relief and the swelling of ADG are discussed in detail. The process of f abricating microlens array does not require the use of expensive equipment, and it is not sophisticated and time consuming. Results are presented for experiments and evaluated by a profile meter and an interference microscope . (C) 2001 Society of Photo-Optical Instrumentation Engineers.