1. 1 Paper Survey Fabrication of various dimensions of high fill-factor micro-lens arrays for OLED package Sensors and Actuators A xxx (2010) xxx–xxx a Department of Mechanical Engineering, R.O.C. Military Academy, Kaohsiung, Taiwan, ROC b Department of Mechanical and Electro-Mechanical Engineering, Center for Nanoscience and Nanotechnology, National Sun-Yat-Sen University, 70 Lien-hai Rd., Kaohsiung 804, Taiwan, ROC c Department of Photonics, National Sun-Yat-Sen University, Kaohsiung 804, Taiwan, ROC Advisee ﹕ Sung-Wen Tsai Institute of Mechanical Engineering Date ﹕ 2010/06/18 K.H. Liua, M.F. Chenb, C.T. Panb, ∗, M.Y. Changc, W.Y. Huangc

2. 2 Outline  The design principle  Fabrication process of gapless hexagonal micro-lens array  Results and discussions  Conclusion

3. The design principle 3 1.T ≧ D ： gap group 2.T ＜ D ： gapless group Fig. 1. The three smaller circles (A, B and C) are the patterns of a mask; three bigger circles which are drawn in dotted line are used to describe the micro-lenses how to interwork; finally, the interworked micro-lenses become hexagonal micro-lenses.Diameter (D) is the original diameter of a pattern on a mask; vertical (V) is a distance of; period (T) is a distance of AB, and it is also a distance of centers of two circles. (D 1 =D 2 =D)

4. T<D(gapless) 4 A BA B A B A B D T v

5. 5 A B A T D B T=D(tangential) v

6. T>D(Not gapless) 6 D T v

7. 7 No.DiameterThickness(H)Vertical(V)Period(T)HypotensueLayoutAspect ratio 14012.51005055.90gapless0.313 23012.51004053.85gapless0.416 32512.51003552.97gapless0.5 41551002551.54gapless0.33 54012.51005055.90Not gapless0.25 62512.51003552.97Not gapless0.5 71551002551.54Not gapless0.313 The design principle Table 1 The designed variables of seven micro-lens arrays (unit: μ m) (aspect ratio = H/D)

8. Fabrication process of gapless hexagonal micro-lens array 8 Fig. 2. A sketch of a circle array on a mask with three parameters. V ： constant value D ： variable T ： variable

9. 9 Fabrication process of gapless hexagonal micro-lens array Fig. 3.Schematic lithography process: (a) spin coating the photoresist AZ4620; (b) a cylindrical array was obtained after development; (c) reflow the microstructures at 140 ◦ C; (d) sputtering a Ni-film as a seed layer

10. 10 Fabrication process of gapless hexagonal micro-lens array Fig. 3.(e) NiCo electroplating was used to wrap the photoresist micro-lenses to form a gapless mold; (f) a passivation treatment with thermal method was applied on the surface of NiCo alloy; (g) a secondary electroplating was performed, and CMP process was used to flat the surface; the substrate was removed.

11. 11 Fig. 4. A replication of UV-cured process: (a) spin coating the polymer on the secondary mold, and exposed to UV light; (b) after several seconds, the polymer was cured. Fabrication process of gapless hexagonal micro-lens array

12. 12 gaples s

13. 13 Not gaples s

14. Results and discussions 14 Fig. 4. The definition of three measured distance of a micro-lens. The three values can be used to calculate the length of Hypotenuse as shown in Fig. 1. This figure was drawn by computer software, Solidworks.

15. 15 No.Diameter aDiameter bDiameter cHypotenuseError(c)Error(hypotenuse) 138.0162.2150.8056.180.80 0.28 240.0959.1040.0953.490.09-0.36 343.2055.6435.2552.470.25-0.5 447.3552.5325.2351.510.23-0.03 526.6157.0250.1148.750.11-7.14 639.4052.1835.2549.060.25-3.91 742.5150.1125.2348.000.23-3.54 Error(C)=Diameter c –T Error(hypotenuse)=measured value – designed value Results and discussions Table 2 The measured data of seven different micro-lens arrays and the error of measured and designed value. Positive errors mean the micro-lenses are bigger than designed one and negative errors mean they are smaller (unit: μ m).

16. Results and discussions 16 Measurement instrument ： SpectraScan Colorimeter PR-650 Fig. 5. Nine points of measurement of an optical film, and an OLED as light source under the optical film (a region of a gray rectangle).

17. 17 Results and discussions

18. 18 Results and discussions

19. 19 Results and discussions

20. 20 Results and discussions

21. 21 Results and discussions

22. 22 Results and discussions

23. 23 Results and discussions

24. 24 Results and discussions

25. 25 Results and discussions

26. 26 Results and discussions Fig. 11. The luminance comparison of a base and an optic film, Sample 3, (a) the comparison of points 1, 3, 4, 6, 7 and 9 of a base and Sample 3, and the raising percentages are 120.59%, 830.90%, 313.42%, 502.86%, 512.35% and 599.82%, respec-tively

27. 27 Results and discussions Fig. 11. (b) the comparison of points 2, 5 and 8 of a base and Sample 3, and the decreasing percentages are 26.88%, 7.74% and 21.85%, respectively.

28. Conclusion 1.A LIGA-like process was applied in this study, because it has good replication for microstructures. 2.The effect of an optical film with gapless and high aspect ratio micro-lens array can show more obvious results than of the other designs. 28

29. 29 Thanks for your attention