Journal of the European Optical Society - Rapid publications, Vol 8 (2013)
Fabrication of adhesive lenses using free surface shaping
Abstract
Two approaches for fabricating polymer lenses are presented in this paper. Both are based on filling circular holes with UV curing adhesives. Initially, the viscous adhesive material creates a liquid and spherical free surface due to its own surface tension. This shape is then preserved by curing with UV-hardening light. For the first approach, the holes are generated in a 4 inch Si-wafer by deep reactive ion etching (DRIE) and for the second, a polydimethylsiloxane (PDMS) mould is manufactured. Three types of UV-curing adhesives are investigated (NOA 61, NOA 88 and NEA 121 by Norland Products). Preliminary to the determination of the lens curvature, a contact angle goniometer is used for taking side view images of the lenses. The radius of curvature is then extracted via image processing with the software MATLAB®. Furthermore, the surface roughness of the PDMS mould and the generated lenses is measured with a white light interferometer to characterize the casting process. The resolution power of the generated lenses is evaluated by measurement of their point spread functions (psf) and modulation transfer functions (mtf), respectively.
© The Authors. All rights reserved. [DOI: 10.2971/jeos.2013.13065]
Citation Details
Cite this articleReferences
J. Chen, W.Wang, J. Fang, and K. Varahramyan, ”Variable-focusing microlens with microfluidic chip,” J. Micromech. Microeng 14, 675–680 (2004).
T. Knieling, M. Shafi, W. Lang, and W. Benecke, ”Microlens array production in a microtechnological dry etch and reflow process for display applications,” J. Europ. Opt. Soc. Rap. Public. 7, 12007 (2012).
M.-K.Wei, J.-H. Lee, H.-Y. Lin, Y.-H. Ho, K.-Y. Chen, C.-C. Lin, C.-F. Wu, et al., ”Efficiency improvement and spectral shift of an organic light-emitting device by attaching a hexagon-based microlens array,” J. Opt. A: Pure Appl. Opt. 10, 055302 (2008).
J.-M. Kang, M.-K. Wei, H.-Y. Lin, J.-H. Lee, H.-Y. Lin, J.-H. Tsai, and T.-C. Wub, ”Shape-controlled microlens arrays fabricated by diffuser lithography,” Microelectronic Engineering 87, 1420–1423 (2010).
H. Schmitt, M. Rommel, A. Bauer, L. Frey, A. Bich, M. Eisner, R. Voelkel, and M. Hornung, ”Full wafer microlens replication by UV imprint lithography,” Microelectronic Engineering 87, 1074–1076 (2010).
R. Zoberbier and R. Voelkel, ”Wafer-Level Cameras: Update on Fabrication and Packaging Technologies,” 3D Packaging 13, 7–8 (2009).
F.-C. Chen, J.-P. Lu, , and W.-K. Huang, ”Using Ink-Jet Printing and Coffee Ring Effect to Fabricate Refractive Microlens Arrays,” IEEE Photonics Technology Letters 21(10), 648–650 (2009).
E. Bonaccursoa, H.-J. Butt, B. Hankeln, B. Niesenhaus, and K. Graf, ”Fabrication of microvessels and microlenses from polymers by solvent droplets,” Appl. Phys. Lett. 86, 124101 (2005).
E.-H. Park, M.-J. Kima, and Y.-S. Kwon, ”Microlens for efficient coupling between LED and optical fiber,” IEEE Photonics Technology Letters 11(4), 439–441 (1999).
P. Nussbaum, I. Philipoussis, A. Husser, and H. Herzig, ”Simple technique for replication of micro-optical elements,” Opt. Eng. 37(6), 1804–1808 (1998).
H. Yang, R. F. Shyu, and J.-W. Huang, ”New production method of convex microlens arrays for integrated fluorescence microfluidic detection systems,” Microsyst Technol 12, 907–912 (2006).
M. Meeder and O. Fähnle, ”In situ shape monitoring of optical cement during UV curing,” in Proceedings of Optical Fabrication and Testing (OSA, New York, 2004).
T. Schultheis, L. S. Molella, and E. Reithmeier, ”An Innovative Concept of a Magnetically Driven Liquid Lens,” in Proceedings of the EOS Conferences at the World of Photonics Congress 2011 (EOS, München, 2011).
T. Schultheis, L. S. Molella, and E. Reithmeier, ”Optical Measurement on a Small Aperture Liquid Lens,” in Proceedings of the 4th EOS Topical Meeting on Optical Microsystems (EOS, Capri, 2011).
Norland Products Inc., http://www.norlandprod.comasat19.06. 2013, Datasheet of NEA 121, NOA 61 and NOA 88 (2013).
W. Zhang, K. Aljasem, H. Zappe, and A. Seifert, ”Highly Flexible MTF measurement system for tunable micro lenses,” Opt. Express 18(12), 12458–12469 (2010).
E. Hecht, Optik (Oldenbourg Wissenschaftsverlag, München, 2005).
H. G., Handbook of Optical Systems (Wiley, New Jersey, 2005).