Abstract

We demonstrate a promising method for fabrication of plastic microlens arrays (MLAs) with a controllable ellipticity and structure, by using the combination of multiple-exposure two-beam interference and plastic replication techniques. Multiple exposures of a two-beam interference pattern with a wavelength of 442nm into a thick positive photoresist (AZ-4620) were used to form different two-dimensional periodic structures. Thanks to the developing effect of the positive photoresist, fabricated structures consisting of hemielliptical- or hemispherical-shaped concave holes were obtained. By controlling the rotation angle between different exposures, both the shape and structure of the holes varied. By adjusting the dosage ratio between different exposures, the shape of the holes was modified while the structure of the holes was unchanged. The photoresist concave microstructures were then transferred to plastic MLAs by employing replication and embossing techniques. The fabricated MLAs were characterized by a scanning electron microscope and atomic force microscope measurements. We show that the ellipticity of the microlenses can be well controlled from 0 (hemispherical) to 0.96 (hemielliptical) by changing the rotation angle or dosage ratio between the two exposures.

© 2011 Optical Society of America

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References

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2009 (1)

2008 (1)

2007 (1)

2006 (2)

2005 (2)

S. Yang, G. Chen, M. Megens, C. K. Ullal, Y. J. Han, R. Rapaport, E. L. Thomas, and J. Aizeberg, “Functional biomimetic microlens array with integrated pores,” Adv. Mater. 17, 435–438 (2005).
[CrossRef]

N. D. Lai, W. P. Liang, J. H. Lin, C. C. Hsu, and C. H. Lin, “Fabrication of two- and three-dimensional periodic structures by multi-exposure of two-beam interference technique,” Opt. Express 13, 9605–9610 (2005).
[CrossRef] [PubMed]

2004 (3)

H. Yang, C. K. Chao, M. K. Wei, and C. P. Lin, “High fill-factor microlens array mold insert fabrication using a thermal reflow process,” J. Micromech. Microeng. 14, 1197–1204(2004).
[CrossRef]

T. K. Shin, J. J. Ho, and J. W. J. Cheng, “A new approach to polymeric microlens array fabrication using soft replica molding,” IEEE Photon. Technol. Lett. 16, 2078–2080 (2004).
[CrossRef]

S. I. Chang and J. B. Yoon, “Shape-controlled, high fill-factor microlens arrays fabricated by a 3D diffuser lithography and plastic replication method,” Opt. Express 12, 6366–6371(2004).
[CrossRef] [PubMed]

2003 (3)

2002 (1)

M. H. Wu and G. M. Whitesides, “Fabrication of two-dimensional arrays of microlenses and their applications in photolithography,” J. Micromech. Microeng. 12, 747–758(2002).
[CrossRef]

1999 (2)

E. H. Park, M. J. Kim, and Y. S. Kwon, “Microlens for efficient coupling between LED and optical fiber,” IEEE Photon. Technol. Lett. 11, 439–441 (1999).
[CrossRef]

K. M. Baker, “Highly corrected close-packed microlens arrays and moth-eye structuring on curved surfaces,” Appl. Opt. 38, 352–356 (1999).
[CrossRef]

1998 (1)

1997 (1)

P. Nussbaum, R. Völkel, H. P. Herzig, M. Eisner, and S. Haselbeck, “Design, fabrication and testing of microlens arrays for sensors and microsystems,” Pure Appl. Opt. 6, 617–636 (1997).
[CrossRef]

1995 (1)

1994 (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, 1112–1114 (1994).
[CrossRef]

1989 (1)

Z. L. Liau, V. Diaduik, J. N. Walpole, and D. E. Mull, “Gallium phosphide microlenses by mass transport,” Appl. Phys. Lett. 55, 97–99 (1989).
[CrossRef]

Aizeberg, J.

S. Yang, G. Chen, M. Megens, C. K. Ullal, Y. J. Han, R. Rapaport, E. L. Thomas, and J. Aizeberg, “Functional biomimetic microlens array with integrated pores,” Adv. Mater. 17, 435–438 (2005).
[CrossRef]

Baker, K. M.

Bu, J.

Cescato, L.

Chang, S. I.

Chao, C. K.

H. Yang, C. K. Chao, M. K. Wei, and C. P. Lin, “High fill-factor microlens array mold insert fabrication using a thermal reflow process,” J. Micromech. Microeng. 14, 1197–1204(2004).
[CrossRef]

Chen, G.

S. Yang, G. Chen, M. Megens, C. K. Ullal, Y. J. Han, R. Rapaport, E. L. Thomas, and J. Aizeberg, “Functional biomimetic microlens array with integrated pores,” Adv. Mater. 17, 435–438 (2005).
[CrossRef]

Chen, T.

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, 1112–1114 (1994).
[CrossRef]

Cheng, J. W. J.

T. K. Shin, J. J. Ho, and J. W. J. Cheng, “A new approach to polymeric microlens array fabrication using soft replica molding,” IEEE Photon. Technol. Lett. 16, 2078–2080 (2004).
[CrossRef]

Cheong, W. C.

Chiang, T. H.

Cox, W. R.

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, 1112–1114 (1994).
[CrossRef]

da Costa, I. F.

Daly, D.

D. Daly, Microlens Arrays (Taylor & Francis, 2001).

Diaduik, V.

Z. L. Liau, V. Diaduik, J. N. Walpole, and D. E. Mull, “Gallium phosphide microlenses by mass transport,” Appl. Phys. Lett. 55, 97–99 (1989).
[CrossRef]

Do, D. B.

Eisner, M.

P. Nussbaum, R. Völkel, H. P. Herzig, M. Eisner, and S. Haselbeck, “Design, fabrication and testing of microlens arrays for sensors and microsystems,” Pure Appl. Opt. 6, 617–636 (1997).
[CrossRef]

Fournier, J. M.

Han, Y. J.

S. Yang, G. Chen, M. Megens, C. K. Ullal, Y. J. Han, R. Rapaport, E. L. Thomas, and J. Aizeberg, “Functional biomimetic microlens array with integrated pores,” Adv. Mater. 17, 435–438 (2005).
[CrossRef]

Haselbeck, S.

P. Nussbaum, R. Völkel, H. P. Herzig, M. Eisner, and S. Haselbeck, “Design, fabrication and testing of microlens arrays for sensors and microsystems,” Pure Appl. Opt. 6, 617–636 (1997).
[CrossRef]

Hayes, D. J.

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, 1112–1114 (1994).
[CrossRef]

He, M.

Herzig, H. P.

P. Nussbaum, R. Völkel, H. P. Herzig, M. Eisner, and S. Haselbeck, “Design, fabrication and testing of microlens arrays for sensors and microsystems,” Pure Appl. Opt. 6, 617–636 (1997).
[CrossRef]

Ho, J. J.

T. K. Shin, J. J. Ho, and J. W. J. Cheng, “A new approach to polymeric microlens array fabrication using soft replica molding,” IEEE Photon. Technol. Lett. 16, 2078–2080 (2004).
[CrossRef]

Hsu, C. C.

Kiel, H. J.

Kim, H.

Kim, J. J.

Kim, M. J.

E. H. Park, M. J. Kim, and Y. S. Kwon, “Microlens for efficient coupling between LED and optical fiber,” IEEE Photon. Technol. Lett. 11, 439–441 (1999).
[CrossRef]

Kwon, Y. S.

E. H. Park, M. J. Kim, and Y. S. Kwon, “Microlens for efficient coupling between LED and optical fiber,” IEEE Photon. Technol. Lett. 11, 439–441 (1999).
[CrossRef]

Lai, N. D.

Lee, B. K.

Lee, D. S.

D. S. Lee, S. S. Min, and M. S. Lee, “Design and analysis of spatially variant microlens-array diffuser with uniform illumination for short-range infrared wireless communications using photometric approach,” Opt. Commun. 219, 49–55(2003).
[CrossRef]

Lee, M. S.

D. S. Lee, S. S. Min, and M. S. Lee, “Design and analysis of spatially variant microlens-array diffuser with uniform illumination for short-range infrared wireless communications using photometric approach,” Opt. Commun. 219, 49–55(2003).
[CrossRef]

Liang, W. P.

Liau, Z. L.

Z. L. Liau, V. Diaduik, J. N. Walpole, and D. E. Mull, “Gallium phosphide microlenses by mass transport,” Appl. Phys. Lett. 55, 97–99 (1989).
[CrossRef]

Lima, C. R. A.

Lin, C. H.

Lin, C. P.

H. Yang, C. K. Chao, M. K. Wei, and C. P. Lin, “High fill-factor microlens array mold insert fabrication using a thermal reflow process,” J. Micromech. Microeng. 14, 1197–1204(2004).
[CrossRef]

Lin, J. H.

MacFarlane, D. L.

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, 1112–1114 (1994).
[CrossRef]

Megens, M.

S. Yang, G. Chen, M. Megens, C. K. Ullal, Y. J. Han, R. Rapaport, E. L. Thomas, and J. Aizeberg, “Functional biomimetic microlens array with integrated pores,” Adv. Mater. 17, 435–438 (2005).
[CrossRef]

Mello, B. de A.

Merenda, F.

Min, S. S.

D. S. Lee, S. S. Min, and M. S. Lee, “Design and analysis of spatially variant microlens-array diffuser with uniform illumination for short-range infrared wireless communications using photometric approach,” Opt. Commun. 219, 49–55(2003).
[CrossRef]

Mull, D. E.

Z. L. Liau, V. Diaduik, J. N. Walpole, and D. E. Mull, “Gallium phosphide microlenses by mass transport,” Appl. Phys. Lett. 55, 97–99 (1989).
[CrossRef]

Narayan, V.

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, 1112–1114 (1994).
[CrossRef]

Ngo, N. Q.

Nussbaum, P.

P. Nussbaum, R. Völkel, H. P. Herzig, M. Eisner, and S. Haselbeck, “Design, fabrication and testing of microlens arrays for sensors and microsystems,” Pure Appl. Opt. 6, 617–636 (1997).
[CrossRef]

Park, E. H.

E. H. Park, M. J. Kim, and Y. S. Kwon, “Microlens for efficient coupling between LED and optical fiber,” IEEE Photon. Technol. Lett. 11, 439–441 (1999).
[CrossRef]

Rapaport, R.

S. Yang, G. Chen, M. Megens, C. K. Ullal, Y. J. Han, R. Rapaport, E. L. Thomas, and J. Aizeberg, “Functional biomimetic microlens array with integrated pores,” Adv. Mater. 17, 435–438 (2005).
[CrossRef]

Rohner, J.

Salathé, R. P.

Schlingloff, G.

Schober, A.

Shin, D. H.

Shin, T. K.

T. K. Shin, J. J. Ho, and J. W. J. Cheng, “A new approach to polymeric microlens array fabrication using soft replica molding,” IEEE Photon. Technol. Lett. 16, 2078–2080 (2004).
[CrossRef]

Tatum, J. A.

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, 1112–1114 (1994).
[CrossRef]

Thomas, E. L.

S. Yang, G. Chen, M. Megens, C. K. Ullal, Y. J. Han, R. Rapaport, E. L. Thomas, and J. Aizeberg, “Functional biomimetic microlens array with integrated pores,” Adv. Mater. 17, 435–438 (2005).
[CrossRef]

Ullal, C. K.

S. Yang, G. Chen, M. Megens, C. K. Ullal, Y. J. Han, R. Rapaport, E. L. Thomas, and J. Aizeberg, “Functional biomimetic microlens array with integrated pores,” Adv. Mater. 17, 435–438 (2005).
[CrossRef]

Völkel, R.

P. Nussbaum, R. Völkel, H. P. Herzig, M. Eisner, and S. Haselbeck, “Design, fabrication and testing of microlens arrays for sensors and microsystems,” Pure Appl. Opt. 6, 617–636 (1997).
[CrossRef]

Walpole, J. N.

Z. L. Liau, V. Diaduik, J. N. Walpole, and D. E. Mull, “Gallium phosphide microlenses by mass transport,” Appl. Phys. Lett. 55, 97–99 (1989).
[CrossRef]

Wei, M. K.

H. Yang, C. K. Chao, M. K. Wei, and C. P. Lin, “High fill-factor microlens array mold insert fabrication using a thermal reflow process,” J. Micromech. Microeng. 14, 1197–1204(2004).
[CrossRef]

Whitesides, G. M.

M. H. Wu and G. M. Whitesides, “Fabrication of two-dimensional arrays of microlenses and their applications in photolithography,” J. Micromech. Microeng. 12, 747–758(2002).
[CrossRef]

Wu, C. Y.

Wu, M. H.

M. H. Wu and G. M. Whitesides, “Fabrication of two-dimensional arrays of microlenses and their applications in photolithography,” J. Micromech. Microeng. 12, 747–758(2002).
[CrossRef]

Yang, H.

H. Yang, C. K. Chao, M. K. Wei, and C. P. Lin, “High fill-factor microlens array mold insert fabrication using a thermal reflow process,” J. Micromech. Microeng. 14, 1197–1204(2004).
[CrossRef]

Yang, S.

S. Yang, G. Chen, M. Megens, C. K. Ullal, Y. J. Han, R. Rapaport, E. L. Thomas, and J. Aizeberg, “Functional biomimetic microlens array with integrated pores,” Adv. Mater. 17, 435–438 (2005).
[CrossRef]

Yoon, J. B.

Yu, W.

Yuan, X.

Adv. Mater. (1)

S. Yang, G. Chen, M. Megens, C. K. Ullal, Y. J. Han, R. Rapaport, E. L. Thomas, and J. Aizeberg, “Functional biomimetic microlens array with integrated pores,” Adv. Mater. 17, 435–438 (2005).
[CrossRef]

Appl. Opt. (6)

Appl. Phys. Lett. (1)

Z. L. Liau, V. Diaduik, J. N. Walpole, and D. E. Mull, “Gallium phosphide microlenses by mass transport,” Appl. Phys. Lett. 55, 97–99 (1989).
[CrossRef]

IEEE Photon. Technol. Lett. (3)

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, 1112–1114 (1994).
[CrossRef]

T. K. Shin, J. J. Ho, and J. W. J. Cheng, “A new approach to polymeric microlens array fabrication using soft replica molding,” IEEE Photon. Technol. Lett. 16, 2078–2080 (2004).
[CrossRef]

E. H. Park, M. J. Kim, and Y. S. Kwon, “Microlens for efficient coupling between LED and optical fiber,” IEEE Photon. Technol. Lett. 11, 439–441 (1999).
[CrossRef]

J. Micromech. Microeng. (2)

H. Yang, C. K. Chao, M. K. Wei, and C. P. Lin, “High fill-factor microlens array mold insert fabrication using a thermal reflow process,” J. Micromech. Microeng. 14, 1197–1204(2004).
[CrossRef]

M. H. Wu and G. M. Whitesides, “Fabrication of two-dimensional arrays of microlenses and their applications in photolithography,” J. Micromech. Microeng. 12, 747–758(2002).
[CrossRef]

Opt. Commun. (1)

D. S. Lee, S. S. Min, and M. S. Lee, “Design and analysis of spatially variant microlens-array diffuser with uniform illumination for short-range infrared wireless communications using photometric approach,” Opt. Commun. 219, 49–55(2003).
[CrossRef]

Opt. Express (5)

Opt. Lett. (1)

Pure Appl. Opt. (1)

P. Nussbaum, R. Völkel, H. P. Herzig, M. Eisner, and S. Haselbeck, “Design, fabrication and testing of microlens arrays for sensors and microsystems,” Pure Appl. Opt. 6, 617–636 (1997).
[CrossRef]

Other (1)

D. Daly, Microlens Arrays (Taylor & Francis, 2001).

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Figures (9)

Fig. 1
Fig. 1

Fabrication process of PDMS MLAs: (a) Record desired 2D periodic structure on AZ-4620 positive photoresist by the multiple-exposure two-beam interference technique. (b) Develop the exposed AZ photoresist to obtain 2D microholes array. (c) Fill PDMS to the photoresist microhole structure. (d) Peel off the photoresist structure to obtain the PDMS MLAs.

Fig. 2
Fig. 2

Calculated light intensity distributions of double-exposure of a two-beam interference pattern with controllable parameters. (a)–(d) Structures obtained by changing the rotation angle (α) and keeping the dosage ratio ( ratio = 1 ). (e)–(h) Structures obtained by changing the dosage ratio while fixing the rotation angle ( α = 90 ° ).

Fig. 3
Fig. 3

SEM photographs of the 2D square structure containing the (a), (b) concave microhole AZ template and (c), (d) hemispherical PDMS microlens.

Fig. 4
Fig. 4

SEM of PDMS MLAs obtained by replication of the AZ templates that were fabricated by double exposure of the two-beam interference pattern at different α angles: (a)  80 ° , (b)  60 ° , (c)  40 ° , and (d)  20 ° . The dosage ratio between two exposures is equal to 1 for all these results.

Fig. 5
Fig. 5

SEM of PDMS MLAs obtained by replication of the photoresist templates, which were fabricated by double exposure of a two-beam interference pattern at different dosage ratios: (a)  1 : 1 , (b) 1 : 0.7 , (c) 1 : 0.5 , and (d)  1 : 0.2 . The rotation angle between two exposures was 90 ° for all results.

Fig. 6
Fig. 6

SEM image of PDMS hemispherical microlenses organized in a hexagonal configuration. This MLA was fabricated by triple exposures of a two-beam interference pattern at 60 ° , 0 ° , and 60 ° . Inset is a SEM image showing the side view of the MLA.

Fig. 7
Fig. 7

Calculated light intensity distributions (at an isointensity of 1.5) of a hexagonal structure obtained with different ratios of dosages between three exposures: (a)  1 : 1 : 1 , (b)  1 : 1 : 0.7 , (c)  1 : 1 : 0.5 , (d)  1 : 1 : 0.4 , (e)  1 : 1 : 0.2 .

Fig. 8
Fig. 8

AFM images and surface profile characterization of fabricated microlenses. (a), (b) Square structure/ hemispherical microlenses. (c), (d) Hexagonal structure/ hemielliptical microlenses. (e), (f) Square structure/hemielliptical microlenses.

Fig. 9
Fig. 9

Dependences of the ellipticity of the microlenses (a) on the rotation angle and (b) on the dosage ratio of two exposures. The inset in (a) illustrates the form of a single elliptical microlens.

Tables (1)

Tables Icon

Table 1 Experimental Values of Focal Lengths of the Various Microlenses Shown in Fig. 8 a

Equations (2)

Equations on this page are rendered with MathJax. Learn more.

R c = H 2 + ( D 2 ) 2 2 H , f = R c n 1 ,
e = 1 D 1 2 D 2 2 ,

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