DOI QR코드

DOI QR Code

Research Trends in Light Guide Plates for LED Backlight Units

LED 백라이트유닛 도광판의 연구동향

  • Park, So Hee (Department of Physics, College of Natural Science, Chosun University) ;
  • Choi, Eun Seo (Department of Physics, College of Natural Science, Chosun University) ;
  • Ahn, Sun Young (Policy and Planning Department, Korea Association for Photonics Industry Development) ;
  • Shin, Yong Jin (Department of Physics, College of Natural Science, Chosun University)
  • Received : 2017.11.06
  • Accepted : 2017.11.29
  • Published : 2017.12.25

Abstract

The display, which is closely related to modern life, is being developed as a window on a network connecting individuals, devices, and even other individuals from simple display devices, as the IT industry develops. To achieve a thinner, brighter unit with less consumption for backlighting, the LED light source has applied, and the study of complex light-guiding plates to improve luminance, uniformity, and viewing angle has been initiated. In this paper, we summarize the research results for the scatterers' pattern formation of the light-guiding plate and the arrangement and composition of the light source, which have enabled remarkable development of the LED backlight unit over the last 10 years. In addition, a large-area flat-screen illumination system, applying the light-guiding-plate technology to a currently noteworthy LED light-fixture design, is outlined. Finally, we discuss the direction and way to develop the current technology more progressively.

현대생활에 매우 밀접하게 연관되어 있는 디스플레이는 IT산업이 발전함에 따라 단순한 표시장치에서 개인과 기기, 더 나아가 또 다른 개인을 연결해주는 네트워크의 창으로서 발전하고 있다. 이와 같은 디스플레이의 가장 중요한 구성요소인 백라이트유닛이 보다 얇고 더 밝으며 전기 소모량도 적게 구현하기 위해서 LED 광원을 적용하였으며, 휘도와 휘도 균일도 및 시야각을 향상 시키기 위한 복합 도광판에 대한 연구가 시작되었다. 본 논문에서는 최근 10여 년간 LED 백라이트 유닛의 괄목할만한 성장을 가능하게 한, 도광판의 산란패턴 형성에 관한 연구와 광원의 배치 및 구성 기술에 관하여 정리하고, 더 나아가 이러한 도광판 기술을 최근 주목을 받고 있는 LED 조명기구 설계에 적용시킨 대면적 flat-type 조명시스템에 대해 개괄적으로 기술한다. 최종적으로 현 기술을 보다 발전적으로 향상시킬 수 있는 방안 및 적용 방법에 관하여 논의한다.

Keywords

References

  1. D. M. Brown, R. Dean, and J. D. Brown, "LED backlight: design, fabrication, and testing," Proc. SPIE 3938, 180-187 (2000).
  2. K. Kalantar, "Optical design of light-guide plates for illumination systems used in mobil phones and PDAs," Asia display, IDW 2001, 517-520 (2001).
  3. M. Anandan, "LCD backlighting," Society for Informational Display Seminar Lecture Notes, 169-250 (2002).
  4. Feng, X. Yang, G. Jin, Y. Yan, and S. Fan, "Integrated light-guide plates that can control the illumination angle for liquid crystal display backlight system," Proc. SPIE 6034, 603406 (2006).
  5. H. Lee, S. H. Jee, S. H. Kim, Y. S. Yoon, and S. H. Kim, "Modeling for new type backlight units," Korean J. Opt. Photon. 21, 41-45 (2010). https://doi.org/10.3807/KJOP.2010.21.2.041
  6. Y-M. Lee, J. H. Lee, and E. C. Jeon, "A study on an integrated light guide plate," Korean J. Opt. Photon. 21, 53-60 (2010). https://doi.org/10.3807/KJOP.2010.21.2.053
  7. Y. C. Kim, "LGP output characteristics depending in BLU pattern size," Korean J. Opt. Photon. 19, 43-47 (2008). https://doi.org/10.3807/HKH.2008.19.1.043
  8. Y. H. Choi, H. J. Ma, E. S. Choi, and Y. J. Shin, "The numerical calculation of simplified light guide panel model with adjustable optical reflectivity," New Physics (The Korean Physical Society) 59, 165-168 (2009).
  9. G. Lee, J. H. Jeong, S.-J. Yoon, and D.-H. Choi, "Design optimization for optical patterns in a light-guide panel to improve illuminance and uniformity of the liquid-crystal display," Opt. Eng. 48, 024001 (2009). https://doi.org/10.1117/1.3083290
  10. J. H. Lee, K.-B. Nahm, J.-H. Ko, and J. H. Kim, "Optimization of optical structure of lightguide panel for uniformity improvement of edge-lit backlight," Korean J. Opt. Photon. 21, 61-68 (2010). https://doi.org/10.3807/KJOP.2010.21.2.061
  11. Y. C. Kim, D.-W. Kim, T.-S. Oh, Y.-M. Lee, S. Ahn, and H.-S. Kim, "LGP pattern desigh by using a pattern density function with simple exponential function," Korean J. Opt. Photon. 21, 97-102 (2010). https://doi.org/10.3807/KJOP.2010.21.3.097
  12. S.-W. Oh, N. Kim, E.-S. Kim, and J.-W. An, "Optimization of the dual-layer LGP for improving luminance and uniformity of edge type back light unit," Korean J. Opt. Photon. 21, 247-253 (2010). https://doi.org/10.3807/KJOP.2010.21.6.247
  13. S. H. Park, S. S. Lee, H. J. Ma, E. S. Choi, and Y. J. Shin, "Simulation of luminance and uniformity of LGP according to the laser scattering pattern," Korean J. Opt. Photon. 21, 225-229 (2010). https://doi.org/10.3807/KJOP.2010.21.6.225
  14. B.-Y. Joo and D.-H. Shin, "Design guidance of backlight optic for improvement of the brightness in the conventional edge lit LCD backlight," Displays 31, 87-92 (2010). https://doi.org/10.1016/j.displa.2010.02.004
  15. B.-Y. Joo, J. J. Kang, and J.-P. Hong, "Analysis of the light-scattering power of patterned dot material printed on the light guide plate in liquid crystal display," Displays 33, 178-185 (2012). https://doi.org/10.1016/j.displa.2012.08.005
  16. S.-H. Park, Y.-J. Shin, E.-S. Choi, H.-J. Ma, and S.-S. Lee, "Improvement of luminance and uniformity of light guide panel using scatterer pattern by laser processing," Opt. Laser Technol. 44, 1301-1306 (2012). https://doi.org/10.1016/j.optlastec.2011.12.040
  17. Y. C. Kim, "Optimize pattern design for the thin LGP," Optik 124, 2171-2173 (2013). https://doi.org/10.1016/j.ijleo.2012.06.070
  18. Y. C. Kim, "LGP pattern design with single LED light source," Optik 125, 1341-1345 (2014). https://doi.org/10.1016/j.ijleo.2013.08.021
  19. E. S. Choi, Y. H. Choi, and Y. J. Shin, "Manipulation of the performance of a light guiding plate by using LED's arrangement," New Physics (The Korean Physical Society) 59, 160-164 (2009).
  20. S. S. Lee, H. J. Ma, Y.-J. Shin, and E. S. Choi, "Evaluation of the light guiding panel performance with a plastic optical fiber source," New Physics (The Korean Physical Society) 62, 994-999 (2012).
  21. S. H. Park, "Analysis of light-emitting effects of a LGP according to the processed POF light source device," New Physics (The Korean Physical Society) 65, 1022-1027 (2015).
  22. S. H. Park, "Optical properties of a light guide plate according to the conditions for processing the side-emitting plastic optical fiber light-source device," New Physics (The Korean Physical Society) 66, 1319-1324 (2016).
  23. Y. S. Kim, T. H. Kim, S. H. Park, Y. H. Choi, E. S. Choi, and Y. J. Shin, "Improvement of light guide panel performance by laser patterning," J. Korean Soc. Laser Process 10, 29-34 (2007).
  24. T.-H. Kim, S.-H. Park, H.-K. Oh, and Y.-J. Shin, "Analysis of the laser patterning inside light guide panel," Opt. Laser Technol. 39, 1437-1442 (2007). https://doi.org/10.1016/j.optlastec.2006.10.002
  25. E. S. Choi, Y. H. Choi, and Y. J. Shin, "Light manipulation in a transparent medium with laser-patterned three-dimensional and surface scatterers," J. Korean Phys. Soc. 55, 2646-2649 (2009). https://doi.org/10.3938/jkps.55.2646
  26. S. S. Lee, H. J. Ma, Y. J. Shin, and E. S. Choi, "Simulation study of uniformity enhancement caused by changing the slope of a slanted plate," New Physics (The Korean Physical Society) 61, 763-767 (2011).
  27. Y. H. Choi, Y. J. Shin, and E. S. Choi, "Performance analysis of light guide panel implemented with laser-processed inner and surface patterns," J. Korean Soc. Laser Process 11, 1-6 (2008).
  28. Y. H. Choi, E. S. Choi, and Y.-J. Shin, "The pattern design and an efficient simulation method for high-luminescence inner-scatterer-based light guide panels," New Physics (The Korean Physical Society) 56, 426-432 (2008).
  29. S. H. Park and Y. J. Shin, "Quantitative analysis of the dependence of the luminance of the light guide plate for a LCD backlight on the scattering angle of the optical patterns," New Physics (The Korean Physical Society) 64, 934-939 (2014).
  30. S.-H. Park and Y.-J. Shin, "Light guide plate with curved V-groove patterns in edge-lit backlight," Opt. Eng. 55, 0151031-0151035 (2016).
  31. S. H. Park, "Dependence of the illuminance of a light guide plate for edge-lit backlight on the shape of the scattering pattern," New Physics (The Korean Physical Society) 67, 890-895 (2017).
  32. H.-D. Yim, D.-J. Lee, Y. G. Kim, and B.-H. O, "Beam pattern analysis of LED reflector design and simplification of the functional design," Korean J. Opt. Photon. 23, 222-226 (2012). https://doi.org/10.3807/KJOP.2012.23.5.222
  33. H.-W. Ku, T.-Y. Lim, J.-H. Hwang, J.-H. Kim, M.-J. Lee, and D. W. Shin, "Development and characterization of translucent opal glass for diffuser of LED lighting," Kor. J. Mater. Res. 22, 650-657 (2012). https://doi.org/10.3740/MRSK.2012.22.12.650
  34. C.-Y. Tsai, "Design and analysis of reflector for uniform light-emitting diode illuminance," J. Opt. Soc. Am. A 30, 993-1001 (2013). https://doi.org/10.1364/JOSAA.30.000993
  35. B.-J. Kim, D.-C Kim, B.-H. O, S.-G. Park, B.-H. Kim, and S. G. Lee, "Optimal design of secondary optics for narrowing the beam angle of an LED lamp with a large-area COB-type LED package," Korean J. Opt. Photon. 25, 78-84 (2014). https://doi.org/10.3807/KJOP.2014.25.2.078
  36. D.-I. Kang, K.-Y. Kim, Y.-M. Yu, and H.-L. Choi, "Optimization and fabrication of color temperature tunable white LED luminaires," Korean J. Opt. Photon. 25, 102-107 (2014). https://doi.org/10.3807/KJOP.2014.25.2.102
  37. H.-Y. Lee and Y.-G. Ju, "Light-emitting-diode illumination system based on a double-stacked cylindrical micro-lens array," New Physics (The Korean Physical Society) 64, 200-205 (2014).
  38. S.-B. Yoon and E.-Y. Chang, "LED source optimization for the LED chip array of the LED luminaires," J. Digital Convergence 14, 419-424 (2016).
  39. J.-Y. Lee, M.-H. Shin, J.-S. Kim, and Y.-J. Kim, "Design of light guide plate to improve optical characteristics for large-area edge-lit LED display," Trans. Soc. Inf. Storage Syst. 9, 10-16 (2013).
  40. S. S. Lee, E. S. Choi, and Y. J. Shin, "Use of simulation to design the optical scattering pattern for LED lighting," New Physics (The Korean Physical Society) 63, 1027-1031 (2013).
  41. S. H. Park and Y. J. Shin, "Optimization of the reflector and the light guide panel for improving the uniformity of large-area flat-type LED lighting," New Physics (The Korean Physical Society) 64, 825-828 (2014).
  42. S. H. Park, T. H. Bang, and Y. J. Shin, "High-precision laser processing of LGP for flat-type LED lighting," New Physics (The Korean Physical Society) 65, 933-937 (2015).
  43. S.-H. Park, Y.-J. Shin, K.-H. Oh, and T.-W. Bang, "Optical characteristics fo LGP depending on the scattering pattern orientation for flat-type LED lighting," Opt. Rev. 23, 172-179 (2016). https://doi.org/10.1007/s10043-016-0193-y
  44. Y. S. Kim and S. Lim, "Design of high uniformity LED backlight," SID International Symposium Digest of Technical Papers 36, 1321-1325 (2005).
  45. A. Mills, "LED backlights poised to penetrate large liquid crystal displays," LEDs Magazine May/June, 36-38 (2007).
  46. Y. J. Shin, Y. S. Kim, S. H. Park, J. W. Lee, W. G. Jung, Z. Chen, and J. S. Nelson, "Analysis of laser engraving image inside crystal and PMMA," Proc. SPIE 5713, 539-544 (2005).
  47. G.-H. Kim, "A PMMA composite as an optical diffuser in a LCD BLU," Eur. Polym. J. 41, 1729-1730 (2005). https://doi.org/10.1016/j.eurpolymj.2005.02.029
  48. G. D. Kim, H. J. Kang, S. H. Ahn, C. K. Song, C. I. back, and C. S. Lee, "Laser-marking process for liquid-crystal display light guide panel," Proc. IMechE 219(B), 565-569 (2005).
  49. Y. S. Kim, E. S. Choi, and Y. J. Shin, "Control of laser parameter for precision line processing," J. Korean Soc. Laser Process 10, 11-17 (2007).
  50. Y.-S. Kim, E. S. Choi, W.-S. Kwak, and Y.-J. Shin, "Analysis of the thermal distribution by using laser-beam irradiation," J. Korean Phys. Soc. 51, 503-508 (2007). https://doi.org/10.3938/jkps.51.503
  51. Y.-J. Shin, Y.-S. Kim, S.-H. Park, J.-W Lee, W.-G. Jung, and Z. Chen, "Analysis of laser engraving image inside crystal and PMMA," Proc. SPIE 5713, 539-544 (2005).