Manufacture of microscale random pattern using indentation machining technology

Abstract

The display industries recently demand new microscale dot-type patterns for thinner and brighter displays with high energy efficiency, which are randomly distributed with irregular separation distances and have uniform optical characteristics. We developed a new program to generate the coordinates of the controlled microscale random patterns considering their diameter and the distance to the nearest pattern for preventing overlap of each pattern. Then the microscale random patterns were machined on a metal mold using the indentation machining which is a simple and low-cost machining method. We decreased the total machining time by the optimization of machining order of the random patterns. The coordinates, the diameter and the fill-factor of the machined patterns by the indentation machining were much consistent to the designed values. The controlled microscale random patterns had uniform optical characteristics over all areas of the manufactured optical film. Moreover, if optical films have the same diameters and fill-factor, they showed the same optical characteristics even they have totally different coordinates of random microscale patterns. This technology is expected to reduce the number of the optical films and the light sources in the display, which can save much energies.

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References

  1. 1.

    Zhou S, Cao B, Liu S, Ding H (2012) Improved light extraction efficiency of GaN-based LEDs with patterned sapphire substrate and patterned ITO. Opt Laser Technol 44:2302–2305

    Article  Google Scholar 

  2. 2.

    Pudis D, Suslik L, Skriniarova L, Kovac L, Kovac J (2013) Effect of 2D photonic structure patterned in the LED surface on emission properties. Appl Surf Sci 269:161–165

    Article  Google Scholar 

  3. 3.

    Jeong SM, Kissinger S, Kim DW, Lee SJ, Kim JS (2010) Characteristic enhancement of the blue LED chip by the growth and fabrication on patterned sapphire (0001) substrate. J Cryst Growth 312:258–262

    Article  Google Scholar 

  4. 4.

    Cho JY, Hong SH, Byeon KJ, Lee H (2012) Light extraction efficiency improvement in GaN based blue light emitting diode with two-dimensional nano-cavity structure. Thin Solid Films 521:115–118

    Article  Google Scholar 

  5. 5.

    Ee YK, Li XH, Biser J, Cao W, Chan HM (2010) Abbreviated MOVPE nucleation of IIIN itride light-emitting diodes on nano-patterned sapphire. J Cryst Growth 312:1311–1315

    Article  Google Scholar 

  6. 6.

    Li CJ, Fang YC, Chu WT, Cheng MC (2018) Design of a prism light-guide plate for an LCD backlight module. J Soc Inf Display 16(4):545–550

    Article  Google Scholar 

  7. 7.

    Li CJ, Fang YC, Cheng MC (2010) Prism-pattern design of an LCD guide plate using a neural-network optical model. Optik 121:2245–2249

    Article  Google Scholar 

  8. 8.

    Zhao WX, Wang QH, Wang AH, Li DH (2010) Autostereoscopic display based on two-layer lenticular lenses. Opt Lett 35:4127–4129

    Article  Google Scholar 

  9. 9.

    Funamoto A, Aoyama S (2003) LED backlight system with double-prism pattern. J Soc Inf Display 11(4):1045–1051

    Google Scholar 

  10. 10.

    Idé T, Numata H, Taira Y, Mizuta H, Suzuki M, Noguchi M, Katsu Y (2003) A novel dot-pattern generation to improve luminance uniformity of LCD backlight. J Soc Inf Display 11(4):659–665

    Article  Google Scholar 

  11. 11.

    Mao X, Li H, Han Y, Luo Y (2014) A two-step design method for high compact rotationally symmetric optical system for LED surface light source. Opt Express 22:A233–A247

    Article  Google Scholar 

  12. 12.

    Fang F, Zhang X, Weckenmann A, Zhang G, Evans C (2013) Manufacturing and measurement of freeform optics. CIRP Ann Manuf Technol 62:823–846

    Article  Google Scholar 

  13. 13.

    Lee YM, Lee JH, Jeon E (2010) A study on an integrated light guide plate. J Opt Soc Korea 21:53–60

    Article  Google Scholar 

  14. 14.

    Shih CJ, Lin WC, Lin CS, Ou SF, Pan YN (2013) Fabrication of diamond conditioners by using a micro patterning and electroforming approach. Microelectron Eng 103:92–98

    Article  Google Scholar 

  15. 15.

    Lim CS, Hong MH, Kumar S, Rahman A, Liu M (2006) Fabrication of concave micro lens array using laser patterning and isotropic etching. Int J Mach Tools Manuf 46:552–558

    Article  Google Scholar 

  16. 16.

    Radtke D, Duparré J, Zeitner UD, Tünnermann A (2007) Laser lithographic fabrication and characterization of a spherical artificial compound eye. Opt Express 15:3067–3077

    Article  Google Scholar 

  17. 17.

    Nayak BK, Gupta MC (2010) Self-organized micro/nano structures in metal surfaces by ultrafast laser irradiation. Opt Laser Technol 48:940–949

    Article  Google Scholar 

  18. 18.

    Jeon E, Lee JR, Choi DH, Choi HJ, Je TJ (2017) A new application of dynamic indentation: indentation machining technology. Exp Mech. https://doi.org/10.1007/s11340-016-0187-5

    Article  Google Scholar 

  19. 19.

    Oh HS, Cho HR, Park H, Hong ST, Chun DM (2016) Study of electrically-assisted indentation for surface texturing. Int J Precis Eng Manuf Green Technol 3:161–165

    Article  Google Scholar 

  20. 20.

    Chaudhri MM, Winter M (1988) The load-bearing area of a hardness indentation. J Phys D Appl Phys 21:370–374

    Article  Google Scholar 

  21. 21.

    McElhaney KW, Vlassak JJ, Nix WD (1998) Determination of indenter tip geometry and indentation contact area for depth sensing indentation experiments. J Mater Res 13:1300–1306

    Article  Google Scholar 

  22. 22.

    Oliver WC, Pharr GM (2004) Measurement of hardness and elastic modulus by instrumented indentation: advances in understanding and refinements to methodology. J Mater Res 19:3–20

    Article  Google Scholar 

  23. 23.

    Cheng YT, Cheng CM (1998) Effects of ‘Sinking in’ and ‘Piling up’ on estimating the contact area under load in indentation. Philos Mag Lett 78:115–120

    Article  Google Scholar 

  24. 24.

    Lee JR, Jeon E, Kim HS, Woo W, Je TJ, Yoo YE, Lee ES (2015) Optical characterization and manufacturing of an optical plate for increasing light efficiency of LED systems. Int J Precis Eng Manuf 16:1355–1360

    Article  Google Scholar 

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Acknowledgements

This work was supported by the 2018 Research Fund of University of Ulsan.

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Correspondence to Hwi Kim or Eun-chae Jeon.

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Lee, J., Moon, S.H., Je, T. et al. Manufacture of microscale random pattern using indentation machining technology. Int. J. of Precis. Eng. and Manuf.-Green Tech. (2020). https://doi.org/10.1007/s40684-020-00240-4

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Keywords

  • Indentation machining
  • Microscale random pattern
  • Fill-factor
  • Optical characteristics