Fabrication Of Refractive Microlens Arrays Research Articles

A high-corrugation-rate self-Processing SiO/sub 2/--ZrO/sub 2/ hybrid sol-gel material for fabrication of microlens array

A novel high-corrugation-rate self-processing SiO/sub 2/--ZrO/sub 2/ hybrid sol-gel material has been developed and employed in single-step fabrication of refractive microlens array (MLA). In the proposed process, the SiO/sub 2/--ZrO/sub 2/ hybrid sol-gel film was exposed to ultraviolet through a binary mask and directly patterned into an MLA, which could be used as an end product with no further development or etching steps. Measurements showed that the surface relief depth could reach 1.32 /spl mu/m, equivalent to 17.1% of the sol-gel film thickness. As expected, the fabricated refractive MLA had excellent surface smoothness, structural and dimensional conformity. The discrepancy between the designed and actual focal length of the MLA was 5.3%. The self-processing, being a true single-step method, was shown to be a practical, cost-effective, and promising fabrication technique for microoptical elements.

Simple reflow technique for fabrication of a microlens array in solgel glass.

A simple reflow method for fabrication of refractive microlens arrays in inorganic-organic SiO2-ZrO2 solgel glass is presented. To our knowledge, this is the first report that presents a simple reflow technique for transforming a negatively induced hybrid solgel material into desirable spherical microlenses. It is shown that the microlenses have excellent smooth surfaces and uniform dimensions. The reflow technique is considerably cheaper than use of a high-energy beam-sensitive gray-scale mask and is suitable for mass production.

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

A new method is developed to fabricate a refractive microlens array by etching ammonium dichromate gelatin (ADG) with enzyme solution. The light exposes ADG through a high contrast binary mask, then the exposed parts of ADG generate a cross-linking reaction. Usually, the relief achieved by water developing is very shallow (<1 ?m), so we compound a 0.2% concentration protein enzyme solution as the developer to develop ADG and deepen its relief. At 37°C, the biochemical reaction occurs between ADG and the enzyme solution, and because of surface tension, ADG turns to spherical structure after developing. The optimum technique parameters of this process are presented. The principle of etching ADG with an enzyme solution to achieve deep relief and the swelling of ADG are discussed in detail. The process of fabricating 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.

Fabrication of refractive microlens arrays by excimer laser ablation of amorphous Teflon

The fabrication of refractive microlens arrays by the technique of excimer laser ablation of doped amorphous Teflon combined with the subsequent annealing and melting of the produced polymer islands is described. The microlenses obtained are optically clear from the far UV (190 m) to the near IR (2000 nm) and are of good optical quality. They vary in size from 50 to 385 µm in diameter with numerical apertures between 0.2 and 0.3. Utilization of these microlenses for material processingby excimer lasers at 193 nm is demonstrated, and possible applications are discussed.