Hybrid polymer microlens arrays with high numerical apertures fabricated using simple ink-jet printing technique

Microlens arrays fabricated by a direct ink-jet printing of UVcurable hybrid polymer are reported. A periodic pattern of polymer drops was ink-jet printed on the surface-treated glass substrate and cured in the UV-light. Using this simple technique, we demonstrated periodic arrays of almost semi-spherical microlenses of 50 μm diameter size and a focal distance of 48μm. The optical characteristics of solitary μ-lenses and arrays comprising up to 64x64 microlenses are measured both in the nearand farfield zones. Large numerical aperture and short focal distance make the inkjet printing of microlenses very attractive for applications in optical interconnects, large 2D VCSEL arrays and pixelated imagine sensors utilizing CCD or SPAD arrays, offering thus an efficient, simple and a cheap alternative to the conventionally used photolithography technique. ©2011 Optical Society of America OCIS codes: (130.0130) Integrated optics; (130.1750) Components; (130.3990) Micro-optical devices; (030.4280) Noise in imaging systems; (220.3630) Lenses; (220.4000) Microstructure fabrication; (160.5470) Polymers; (160.6060) Solgel. References and links 1. D. L. MacFarlane, V. Narayan, J. A. Tatum, W. R. Cox, T. Chen, and D. J. Hayes, “Microjet fabrication of microlens arrays,” IEEE Photon. Technol. Lett. 6(9), 1112–1114 (1994). 2. H. Ottevaere, R. Cox, H. P. Herzig, T. Miyashita, K. Naessens, M. Taghizadeh, R. Volkel, H. J. Woo, and H. Thienpont, “Comparing glass and plastic refractive microlenses fabricated with different technologies,” J. Opt. A, Pure Appl. Opt. 8(7), S407–S429 (2006). 3. Z. D. Popovic, R. A. Sprague, and G. A. N. Connell, “Technique for monolithic fabrication of microlens arrays,” Appl. Opt. 27(7), 1281–1284 (1988). 4. C. Croutxé-Barghorn, O. Soppera, and D. J. Lougnot, “Fabrication of refractive microlens arrays by visible irradiation of acrylic monomers: influence of photonic parameters,” Eur. Phys. J. Appl. Phys. 13(1), 31–37 (2001). 5. A. Tripathi, T. V. Chokshi, and N. Chronis, “A high numerical aperture, polymer-based, planar microlens array,” Opt. Express 17(22), 19908–19918 (2009). 6. M. He, X.-C. Yuan, N. Q. Ngo, J. Bu, and S. H. Tao, “Single-step fabrication of a microlens array in sol-gel material by direct laser writing and its application in optical coupling,” J. Opt. A, Pure Appl. Opt. 6(1), 94–97 (2004). 7. D. Wu, S. Wu, L. Niu, Q. Chen, R. Wang, J. Song, H. Fang, and H. Sun, “High numerical aperture microlens arrays of close packing,” Appl. Phys. Lett. 97(3), 031109 (2010). 8. W. Cheong, L. Yuan, V. Koudriachov, and W. Yu, “High sensitive SiO2/TiO2 hybrid sol-gel material for fabrication of 3 dimensional continuous surface relief diffractive optical elements by electron-beam lithography,” Opt. Express 10(14), 586–590 (2002), http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-10-14-586. 9. V. Fakhfouri, N. Cantale, G. Mermoud, J. Y. Kim, D. Boiko, E. Charbon, A. Martinoli, and J. Brugger, “Inkjet printing of SU-8 for polymer-based MEMS a case study for microlenses,” in Proceedings of 21st IEEE International Conference on Micro Electro Mechanical Systems MEMS 2008 (Tucson, AZ, 2008), pp. 407–410. #142920 $15.00 USD Received 22 Feb 2011; revised 14 May 2011; accepted 14 May 2011; published 25 May 2011 (C) 2011 OSA 1 June 2011 / Vol. 1, No. 2 / OPTICAL MATERIALS EXPRESS 259 10. Y. S. Yang, D. H. Youn, S. H. Kim, S. Ch. Lim, H. S. Shim, S. Y. Kang, and I. K. You, “Preparation and characteristics of pmma microlens array for a blu application by an inkjet printing method,” Mol. Cryst. Liq. Cryst. (Phila. Pa.) 520, 239–244 (2010). 11. C. H. Tien, C. H. Hung, and T. H. Yu, “Microlens arrays by direct-writing inkjet print for LCD backlighting applications,” IEEE J. Display Technol. 5(5), 147–151 (2009). 12. S. Obi, M. T. Gale, C. Gimkiewicz, and S. Westenhofer, “Replicated optical MEMS in sol-gel materials,” IEEE J. Sel. Top. Quantum Electron. 10(3), 440–444 (2004). 13. P. Ruffieux, T. Scharf, H. P. Herzig, R. Völkel, and K. J. Weible, “On the chromatic aberration of microlenses,” Opt. Express 14(11), 4687–4694 (2006), http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-14-11-4687. 14. S. A. Akhmanov Y. E. D'yakov, and A. S. Chirkin, Introduction to Statistical Radiophysics and Optics (Nauka, Moscow, 1981), pp. 306–307. 15. A. A. Grütter, H. P. Weber, and R. Dändliker, “Imperfectly mode-locked laser emission and its effects on nonlinear optics,” Phys. Rev. 185(2), 629–643 (1969).