OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 19, Iss. 27 — Dec. 19, 2011
  • pp: 26000–26005
« Show journal navigation

Formation of micro protrusive lens arrays atop poly(methyl methacrylate)

Yong Zhao, Chang Chun Wang, Wei Min Huang, Hendra Purnawali, and Lin An  »View Author Affiliations


Optics Express, Vol. 19, Issue 27, pp. 26000-26005 (2011)
http://dx.doi.org/10.1364/OE.19.026000


View Full Text Article

Acrobat PDF (3369 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

Different sized/shaped micro protrusive lens arrays atop poly(methyl methacrylate) can be fabricated by a simple two-step method, i.e., indentation followed by immersion in ethanol. Profile and projection of obtained microlenses were characterized. Thermal stability of microlenses was examined at 25°C and 60°C. This work demonstrates a cost effective approach for massive fabrication of microlens array with high reliability.

© 2011 OSA

1. Introduction

Microlens array (MLA) is a useful optical element with wide applications in liquid crystal display, wavefront sensor, image recorder, optical signal processing, and interconnection, etc [1

1. H. P. D. Shieh, Y. P. Huang, and K. W. Chien, “Micro-optics for liquid crystal displays application,” J. Disp. Technol. 1(1), 62–76 (2005). [CrossRef]

4

4. H. Toshiyoshi, G. D. J. Su, J. LaCosse, and M. C. Wu, “A surface micromachined optical scanner array using photoresist lenses fabricated by a thermal reflow process,” J. Lightwave Technol. 21(7), 1700–1708 (2003). [CrossRef]

]. Fabrication of MLAs in a low cost, highly efficient and highly reliable way is of great interest to many engineering applications. A number of methods have been reported so far. Apart from conventional injection molding, fluidic lens, slow tool servo method and roller imprinting are some among others [5

5. B. K. Lee, D. S. Kim, and T. H. Kwon, “Replication of microlens arrays by injection molding,” Microsyst. Technol. 10(6-7), 531–535 (2004). [CrossRef]

11

11. H. Yabu and M. Shimomura, “Simple fabrication of micro lens arrays,” Langmuir 21(5), 1709–1711 (2005). [CrossRef] [PubMed]

]. All of them are more applicable for larger sized lenses (i.e., in millimeter and above scale for the diameter). It is difficult to make micro sized lenses (i.e., with a diameter less than 100 μm) due to reasons, such as high flow resistance during filling in micro channel/mold, difficulties in master mold fabrication and ultraprecision position controlling. Some special techniques have been developed for fabricating small sized lens array, such as ink-jet printing [12

12. V. J. Cadarso, J. Perera-Núñez, L. Jacot-Descombes, K. Pfeiffer, U. Ostrzinski, A. Voigt, A. Llobera, G. Grützer, and J. Brugger, “Microlenses with defined contour shapes,” Opt. Express 19(19), 18665–18670 (2011). [CrossRef] [PubMed]

, 13

13. J. P. Lu, W. K. Huang, and F. C. Chen, “Self-positioning microlens arrays prepared using ink-jet printing,” Opt. Eng. 48(7), 073606 (2009). [CrossRef]

], soft lithography [14

14. A. Tripathi, T. V. Chokshi, and N. Chronis, “A high numerical aperture, polymer-based, planar microlens array,” Opt. Express 17(22), 19908–19918 (2009). [CrossRef] [PubMed]

, 15

15. J. M. Park, Z. Gan, W. Y. Leung, R. Liu, Z. Ye, K. Constant, J. Shinar, R. Shinar, and K. M. Ho, “Soft holographic interference lithography microlens for enhanced organic light emitting diode light extraction,” Opt. Express 19(S4Suppl 4), A786–A792 (2011). [CrossRef] [PubMed]

], electrohydrodynamic instability method [16

16. Y. J. Lee, Y. W. Kim, Y. K. Kim, C. J. Yu, J. S. Gwag, and J. H. Kim, “Microlens array fabricated using electrohydrodynamic instability and surface properties,” Opt. Express 19(11), 10673–10678 (2011). [CrossRef] [PubMed]

], and some novel liquid\solvent approaches [17

17. H. Ren, D. Ren, and S. T. Wu, “A new method for fabricating high density and large aperture ratio liquid microlens array,” Opt. Express 17(26), 24183–24188 (2009). [CrossRef] [PubMed]

], etc. However, all these methods require to fabricate a pre-patterned mold/mask by semiconductor processing techniques (e.g. lithography and etching), which is expensive and complicate. In addition, most of the reported methods are based on polydimethylsiloxane (PDMS). It is well known that poly(methyl methacrylate) (PMMA) is a widely used optical polymer with excellent optical properties. However, few PMMA MLAs are reported today [18

18. F. Beinhorn, J. Ihlemann, K. Luther, and J. Troe, “Micro-lens arrays generated by UV laser irradiation of doped PMMA,” Appl. Phys., A Mater. Sci. Process. 68(6), 709–713 (1999). [CrossRef]

, 19

19. L. Li and A. Y. Yi, “Development of a 3D artificial compound eye,” Opt. Express 18(17), 18125–18137 (2010). [CrossRef] [PubMed]

].

2. Fabrication of individual micro protrusions

Figure 1
Fig. 1 Formation of micro protrusions.
shows the fabrication procedure of micro protrusions. A cast PMMA sheet with a thickness of 1 mm and a glass transition temperature of 110°C (from Ying Kwang Acrylic, Singapore) was cut into small pieces for our experiments. A micro hardness tester (CSM instruments) was used to make two different shaped indents atop PMMA at room temperature (refer to Figs. 1(a1) and 1(a3)). One indenter is a spherical conical diamond indenter with a radius of 20 μm and a conical angle of 90°. The other is a square pyramid indenter, with an angle of 130° between two edges. All indentation tests were conducted at room temperature (about 22°C) with a maximum load of 150 mN and a loading/unloading speed of 5 mN/s (with 10s holding time between loading and unloading). The resulted indents were characterized by an optical imaging profiler (Sensofar ® PLu), which is a combination of confocal and interferometry techniques, as shown in Figs. 1(a2) and 1(a4).

Upon indented to a maximum load of P, the corresponding maximum depth and diameter/width of the indent are denoted as hi and wi, respectively (Figs. 1(a1) and 1(a3)). After indentation, the residual maximum depth and diameter/width of indent are denoted as hr and wr, respectively (Figs. 1(b1) and 1(b3)). Subsequently, the PMMA samples were immersed in room temperature ethanol (concentration 95%) for 24 hours. Figures 1(b1) and 1(b3) show ethanol induced protrusions atop PMMA samples with a height of hf and diameter (width) of wf. A spherical indent results in a spherical protrusion (Fig. 1(b2)); while a pyramid indent produces a pyramid protrusion (Fig. 1(b4)). The formation of protrusions is a result of residual stress (in the indents) enhanced swelling during absorption of ethanol by PMMA [22

22. J. P. Harmon, S. Lee, and J. C. M. Li, “Anisotropic methanol transport in PMMA after mechanical deformation,” Polymer (Guildf.) 29(7), 1221–1226 (1988). [CrossRef]

, 23

23. Y. Zhao, C. C. Wang, W. M. Huang, and H. Purnawali, “Buckling of poly(methyl methacrylate) in stimulus-responsive shape recovery,” Appl. Phys. Lett. 99(13), 131911 (2011). [CrossRef]

].

3. Fabrication of microlens array and thermal stability

The simple two-step method (in section 2) can be utilized in MLAs fabrication. Refer to Fig. 2
Fig. 2 MLAs and surface profile.
. First, two indent arrays with different patterns/density were fabricated atop two pieces of PMMA (Fig. 2(a)); and then these samples were immersed into room temperature ethanol, which resulted in lens arrays with different patterns after 9 hours (Fig. 2(b)). Cross-sectional view of indents/protrusions is presented in Fig. 2(c1) for comparison. These lenses are well-ordered, densely packed and have an individual size of about 40 μm (wf) and a height (hf) of about 1 μm (refer to Fig. 1 for definitions of wf and hf). Figure 2(c2) further reveals the evolution process from indent to protrusion after being immersed into ethanol for different periods of time. As indentation was conducted at room temperature, at which PMMA is hard, the resulted spherical indent is actually pile-up [24

24. W. M. Huang, J. F. Su, M. H. Hong, and B. Yang, “Pile-up and sink-in in micro-indentation of a NiTi shape-memory alloy,” Scr. Mater. 53(9), 1055–1057 (2005). [CrossRef]

]. Upon immersing into ethanol, pile-up grows gradually before spherical protrusion is finally formed (after about 4-hour immersion) and then grows (a useful phenomenon, which can be used to control the density of lenses array and size of lenses, and consequently, to manipulate curvature, conic constant and focus length of lens). As we can see, after 9 hours, wf is about 40 μm, which is about doubled from wr; while hf is about 1 μm, which is about 0.5 times larger than hr.

Since this method is based on swelling of PMMA upon immersing into ethanol, desorption of ethanol may be an issue which brings the reliability issue of these MLAs into question. To address this point, different sized spherical lenses were fabricated on different PMMA samples following the above two-step method and then put inside an oven of 25°C or 60°C.

Figure 3
Fig. 3 Thermal stability of MLAs.
(a1) shows surface profile of an indent array, in which three different sized indents were made by a 20 μm spherical indenter under three different maximum loads (namely, 150 mN, 100 mN and 80 mN, respectively). Figure 3(a2) reveals the surface profile (MLA) after immersion in ethanol for 24 hours. Figures 3(a3) and 3(a4) present two typical MLA surface profiles after being kept inside an oven for thermal stability test. It was found that MLAs were stabilized after 168 hours inside a 25°C oven, while it took 24 hours if the oven temperature was set to be 60°C. Figure 3(b) compares the profiles of lenses after 24, 168 and 360 hours inside 60°C oven. It is concluded that all three sized lens arrays are stable after 24 hours at 60°C. Figure 3(c) plots the evolution of the center points of three different sized indents/protrusions (depth/height) against time of the whole process (i.e., after indentation, immersion in ethanol and placed in 60°C oven). It can be seen that there are three major stages during the whole process. The first is the gradual formation of micro lens during immersion in ethanol (from indent to protrusion in 24 hours). Relaxation due to desorption of ethanol is followed (decrease in protrusion height in 60°C oven for 24 hours). After this, MLA becomes stable (no visible change in height in 60°C air for 360 hours).

The stabilized MLA (Fig. 2(b1)), after being put in 60°C oven for 24 hours) have a diameter of 39.95 ± 0.55 μm, center-to-center distance of 40 μm and a sag height of 0.8 ± 0.02 μm.

4. Characterization

Projection experiment was conducted on stabilized MLAs. Refer to Fig. 4(a)
Fig. 4 Projection experiment and results.
for the experimental setup. The optical scope is a microscope (Axiotech 100 HD, Zeiss). A PMMA MLA was placed atop a stage and illuminated with white light from bottom through a mask with a letter E (size 12 × 18 mm) in the middle. The projected image at the top was recorded by a CCD system. Figures 4(b) and 4(c) show the focus spot and projected images through two MLAs (as shown in Figs. 2(b1) and 2(b2)). The focus length of these MLAs measured to be 500 μm by this optical microscope system. It can be seen that letter Es are clearly projected.

For an ideal spherical curve, the radius (R), focal length (f) and numerical aperture (NA) of the lens can be calculated from [25

25. J. T. Wu and S. Y. Yang, “A gasbag-roller-assisted UV imprinting technique for fabrication of a microlens array on a PMMA substrate,” J. Micromech. Microeng. 20(8), 085038 (2010). [CrossRef]

]
R=wf2+4hf28hf,f=Rn1,NA=wf2f
(1)
where wf, hf and n are the diameter, the sag height and the refractive index of PMMA, respectively. For PMMA used in these experiments, n is about 1.49.

5. Conclusions

In summary, we developed a two-step method to fabricate MLAs by means of immersing pre-indented PMMA samples in ethanol. This method is simple, low cost and efficient for massive fabrication over a large area. Furthermore, as demonstrated, the size and shape of lenses are tunable by varying the indentation parameters and ethanol absorption time. After following the thermal stability process, the resulted MLAs become highly stable.

Acknowledgments

This project is partially supported by DSO (DSOCL 09292), Singapore.

References and links

1.

H. P. D. Shieh, Y. P. Huang, and K. W. Chien, “Micro-optics for liquid crystal displays application,” J. Disp. Technol. 1(1), 62–76 (2005). [CrossRef]

2.

G. Y. Yoon, T. Jitsuno, M. Nakatsuka, and S. Nakai, “Shack Hartmann wave-front measurement with a large F-number plastic microlens array,” Appl. Opt. 35(1), 188–192 (1996). [CrossRef] [PubMed]

3.

D. A. Baillie and J. E. Gendler, “Zero-space microlenses for CMOS image sensors: Optical modeling and lithographic process development,” Proc. SPIE 5377, 953–959 (2004). [CrossRef]

4.

H. Toshiyoshi, G. D. J. Su, J. LaCosse, and M. C. Wu, “A surface micromachined optical scanner array using photoresist lenses fabricated by a thermal reflow process,” J. Lightwave Technol. 21(7), 1700–1708 (2003). [CrossRef]

5.

B. K. Lee, D. S. Kim, and T. H. Kwon, “Replication of microlens arrays by injection molding,” Microsyst. Technol. 10(6-7), 531–535 (2004). [CrossRef]

6.

D. Y. Zhang, N. Justis, and Y. H. Lo, “Integrated fluidic adaptive zoom lens,” Opt. Lett. 29(24), 2855–2857 (2004). [CrossRef] [PubMed]

7.

S. H. Cho, F. S. Tsai, W. Qiao, N. H. Kim, and Y. H. Lo, “Fabrication of aspherical polymer lenses using a tunable liquid-filled mold,” Opt. Lett. 34(5), 605–607 (2009). [CrossRef] [PubMed]

8.

R. Marks, D. L. Mathine, G. Peyman, J. Schwiegerling, and N. Peyghambarian, “Adjustable fluidic lenses for ophthalmic corrections,” Opt. Lett. 34(4), 515–517 (2009). [CrossRef] [PubMed]

9.

A. Y. Yi and L. Li, “Design and fabrication of a microlens array by use of a slow tool servo,” Opt. Lett. 30(13), 1707–1709 (2005). [CrossRef] [PubMed]

10.

C. N. Hu, H. T. Hsieh, and G. D. J. Su, “Fabrication of microlens arrays by a rolling process with soft polymethylsiloxane molds,” J. Micromech. Microeng. 21(6), 065013 (2011). [CrossRef]

11.

H. Yabu and M. Shimomura, “Simple fabrication of micro lens arrays,” Langmuir 21(5), 1709–1711 (2005). [CrossRef] [PubMed]

12.

V. J. Cadarso, J. Perera-Núñez, L. Jacot-Descombes, K. Pfeiffer, U. Ostrzinski, A. Voigt, A. Llobera, G. Grützer, and J. Brugger, “Microlenses with defined contour shapes,” Opt. Express 19(19), 18665–18670 (2011). [CrossRef] [PubMed]

13.

J. P. Lu, W. K. Huang, and F. C. Chen, “Self-positioning microlens arrays prepared using ink-jet printing,” Opt. Eng. 48(7), 073606 (2009). [CrossRef]

14.

A. Tripathi, T. V. Chokshi, and N. Chronis, “A high numerical aperture, polymer-based, planar microlens array,” Opt. Express 17(22), 19908–19918 (2009). [CrossRef] [PubMed]

15.

J. M. Park, Z. Gan, W. Y. Leung, R. Liu, Z. Ye, K. Constant, J. Shinar, R. Shinar, and K. M. Ho, “Soft holographic interference lithography microlens for enhanced organic light emitting diode light extraction,” Opt. Express 19(S4Suppl 4), A786–A792 (2011). [CrossRef] [PubMed]

16.

Y. J. Lee, Y. W. Kim, Y. K. Kim, C. J. Yu, J. S. Gwag, and J. H. Kim, “Microlens array fabricated using electrohydrodynamic instability and surface properties,” Opt. Express 19(11), 10673–10678 (2011). [CrossRef] [PubMed]

17.

H. Ren, D. Ren, and S. T. Wu, “A new method for fabricating high density and large aperture ratio liquid microlens array,” Opt. Express 17(26), 24183–24188 (2009). [CrossRef] [PubMed]

18.

F. Beinhorn, J. Ihlemann, K. Luther, and J. Troe, “Micro-lens arrays generated by UV laser irradiation of doped PMMA,” Appl. Phys., A Mater. Sci. Process. 68(6), 709–713 (1999). [CrossRef]

19.

L. Li and A. Y. Yi, “Development of a 3D artificial compound eye,” Opt. Express 18(17), 18125–18137 (2010). [CrossRef] [PubMed]

20.

N. Liu, Q. Xie, W. M. Huang, S. J. Phee, and N. Q. Guo, “Formation of micro protrusion arrays atop shape memory polymer,” J. Micromech. Microeng. 18(2), 027001 (2008). [CrossRef]

21.

Y. Zhao, W. M. Huang, and Y. Q. Fu, “Formation of micro/nano-scale wrinkling patterns atop shape memory polymers,” J. Micromech. Microeng. 21(6), 067007 (2011). [CrossRef]

22.

J. P. Harmon, S. Lee, and J. C. M. Li, “Anisotropic methanol transport in PMMA after mechanical deformation,” Polymer (Guildf.) 29(7), 1221–1226 (1988). [CrossRef]

23.

Y. Zhao, C. C. Wang, W. M. Huang, and H. Purnawali, “Buckling of poly(methyl methacrylate) in stimulus-responsive shape recovery,” Appl. Phys. Lett. 99(13), 131911 (2011). [CrossRef]

24.

W. M. Huang, J. F. Su, M. H. Hong, and B. Yang, “Pile-up and sink-in in micro-indentation of a NiTi shape-memory alloy,” Scr. Mater. 53(9), 1055–1057 (2005). [CrossRef]

25.

J. T. Wu and S. Y. Yang, “A gasbag-roller-assisted UV imprinting technique for fabrication of a microlens array on a PMMA substrate,” J. Micromech. Microeng. 20(8), 085038 (2010). [CrossRef]

OCIS Codes
(220.0220) Optical design and fabrication : Optical design and fabrication
(220.3630) Optical design and fabrication : Lenses
(350.3950) Other areas of optics : Micro-optics

ToC Category:
Optical Design and Fabrication

History
Original Manuscript: October 12, 2011
Revised Manuscript: November 6, 2011
Manuscript Accepted: November 6, 2011
Published: December 6, 2011

Citation
Yong Zhao, Chang Chun Wang, Wei Min Huang, Hendra Purnawali, and Lin An, "Formation of micro protrusive lens arrays atop poly(methyl methacrylate)," Opt. Express 19, 26000-26005 (2011)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-27-26000


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. H. P. D. Shieh, Y. P. Huang, and K. W. Chien, “Micro-optics for liquid crystal displays application,” J. Disp. Technol.1(1), 62–76 (2005). [CrossRef]
  2. G. Y. Yoon, T. Jitsuno, M. Nakatsuka, and S. Nakai, “Shack Hartmann wave-front measurement with a large F-number plastic microlens array,” Appl. Opt.35(1), 188–192 (1996). [CrossRef] [PubMed]
  3. D. A. Baillie and J. E. Gendler, “Zero-space microlenses for CMOS image sensors: Optical modeling and lithographic process development,” Proc. SPIE5377, 953–959 (2004). [CrossRef]
  4. H. Toshiyoshi, G. D. J. Su, J. LaCosse, and M. C. Wu, “A surface micromachined optical scanner array using photoresist lenses fabricated by a thermal reflow process,” J. Lightwave Technol.21(7), 1700–1708 (2003). [CrossRef]
  5. B. K. Lee, D. S. Kim, and T. H. Kwon, “Replication of microlens arrays by injection molding,” Microsyst. Technol.10(6-7), 531–535 (2004). [CrossRef]
  6. D. Y. Zhang, N. Justis, and Y. H. Lo, “Integrated fluidic adaptive zoom lens,” Opt. Lett.29(24), 2855–2857 (2004). [CrossRef] [PubMed]
  7. S. H. Cho, F. S. Tsai, W. Qiao, N. H. Kim, and Y. H. Lo, “Fabrication of aspherical polymer lenses using a tunable liquid-filled mold,” Opt. Lett.34(5), 605–607 (2009). [CrossRef] [PubMed]
  8. R. Marks, D. L. Mathine, G. Peyman, J. Schwiegerling, and N. Peyghambarian, “Adjustable fluidic lenses for ophthalmic corrections,” Opt. Lett.34(4), 515–517 (2009). [CrossRef] [PubMed]
  9. A. Y. Yi and L. Li, “Design and fabrication of a microlens array by use of a slow tool servo,” Opt. Lett.30(13), 1707–1709 (2005). [CrossRef] [PubMed]
  10. C. N. Hu, H. T. Hsieh, and G. D. J. Su, “Fabrication of microlens arrays by a rolling process with soft polymethylsiloxane molds,” J. Micromech. Microeng.21(6), 065013 (2011). [CrossRef]
  11. H. Yabu and M. Shimomura, “Simple fabrication of micro lens arrays,” Langmuir21(5), 1709–1711 (2005). [CrossRef] [PubMed]
  12. V. J. Cadarso, J. Perera-Núñez, L. Jacot-Descombes, K. Pfeiffer, U. Ostrzinski, A. Voigt, A. Llobera, G. Grützer, and J. Brugger, “Microlenses with defined contour shapes,” Opt. Express19(19), 18665–18670 (2011). [CrossRef] [PubMed]
  13. J. P. Lu, W. K. Huang, and F. C. Chen, “Self-positioning microlens arrays prepared using ink-jet printing,” Opt. Eng.48(7), 073606 (2009). [CrossRef]
  14. A. Tripathi, T. V. Chokshi, and N. Chronis, “A high numerical aperture, polymer-based, planar microlens array,” Opt. Express17(22), 19908–19918 (2009). [CrossRef] [PubMed]
  15. J. M. Park, Z. Gan, W. Y. Leung, R. Liu, Z. Ye, K. Constant, J. Shinar, R. Shinar, and K. M. Ho, “Soft holographic interference lithography microlens for enhanced organic light emitting diode light extraction,” Opt. Express19(S4Suppl 4), A786–A792 (2011). [CrossRef] [PubMed]
  16. Y. J. Lee, Y. W. Kim, Y. K. Kim, C. J. Yu, J. S. Gwag, and J. H. Kim, “Microlens array fabricated using electrohydrodynamic instability and surface properties,” Opt. Express19(11), 10673–10678 (2011). [CrossRef] [PubMed]
  17. H. Ren, D. Ren, and S. T. Wu, “A new method for fabricating high density and large aperture ratio liquid microlens array,” Opt. Express17(26), 24183–24188 (2009). [CrossRef] [PubMed]
  18. F. Beinhorn, J. Ihlemann, K. Luther, and J. Troe, “Micro-lens arrays generated by UV laser irradiation of doped PMMA,” Appl. Phys., A Mater. Sci. Process.68(6), 709–713 (1999). [CrossRef]
  19. L. Li and A. Y. Yi, “Development of a 3D artificial compound eye,” Opt. Express18(17), 18125–18137 (2010). [CrossRef] [PubMed]
  20. N. Liu, Q. Xie, W. M. Huang, S. J. Phee, and N. Q. Guo, “Formation of micro protrusion arrays atop shape memory polymer,” J. Micromech. Microeng.18(2), 027001 (2008). [CrossRef]
  21. Y. Zhao, W. M. Huang, and Y. Q. Fu, “Formation of micro/nano-scale wrinkling patterns atop shape memory polymers,” J. Micromech. Microeng.21(6), 067007 (2011). [CrossRef]
  22. J. P. Harmon, S. Lee, and J. C. M. Li, “Anisotropic methanol transport in PMMA after mechanical deformation,” Polymer (Guildf.)29(7), 1221–1226 (1988). [CrossRef]
  23. Y. Zhao, C. C. Wang, W. M. Huang, and H. Purnawali, “Buckling of poly(methyl methacrylate) in stimulus-responsive shape recovery,” Appl. Phys. Lett.99(13), 131911 (2011). [CrossRef]
  24. W. M. Huang, J. F. Su, M. H. Hong, and B. Yang, “Pile-up and sink-in in micro-indentation of a NiTi shape-memory alloy,” Scr. Mater.53(9), 1055–1057 (2005). [CrossRef]
  25. J. T. Wu and S. Y. Yang, “A gasbag-roller-assisted UV imprinting technique for fabrication of a microlens array on a PMMA substrate,” J. Micromech. Microeng.20(8), 085038 (2010). [CrossRef]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

Figures

Fig. 1 Fig. 2 Fig. 3
 
Fig. 4
 

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited