Optimization of Optical Structure of Lightguide Panel for Uniformity Improvement of Edge-lit Backlight

엣지형 LED 백라이트의 균일도 향상을 위한 도광판의 광구조 최적화

  • 이정호 (한림대학교 전자물리학과) ;
  • 남기봉 (한림대학교 전자물리학과) ;
  • 고재현 (한림대학교 전자물리학과) ;
  • 김중현 (삼성전자(주), LCD 총괄)
  • Received : 2010.01.29
  • Accepted : 2010.03.18
  • Published : 2010.04.25


Optical simulation methods were applied to the edge-lit LED backlight for LCD TV applications in order to optimize the optical structure of the light guide plate(LGP), and thus to improve the uniformity properties by removing the bright spots caused by LED's. The edge-lit LED backlight consisted of three white LED's with a lamp cover, a light guide plate, and a reflection film. When there was no pattern on the entrance side surface of the LGP, the illuminance uniformity was sensitively dependent on the distance d between the LED and the entrance surface. The illuminance uniformity increased with d but its increasing rate slowed down when d was beyond ~ 1.5 mm. When micro-patterns such as a lenticular lens array (LLA) or a serration pattern were formed on the entrance surface, the illuminance uniformity was improved substantially even for the case of very small d. At the same simulation condition, the lightguide with serration pattern showed a better uniformity than that with LLA pattern. Additional improvement could be achieved by changing the refractive index of the micro-patterns. These results suggest that using micro-patterns is a very effective way to reduce the bright spots due to their refracting function for the concentrated incident rays onto the LGP.


Supported by : (주)지엘에스


  1. M. Anandan, “LED backlight for LCD/TV monitor: issuesthat remain,” in Proc. SID ‘06 Tech. Digest (San Francisco,USA, May 2006), pp. 1509-1512.
  2. A. Mills, “LED backlights poised to penetrate larger liquidcrystal displays,” LEDs Magazine May/June, 36-38 (2007).
  3. J. S. Ryu, M.-Y. Yu, S.-M. Park, S. J. Kim, and J.-H. Ko,“Initial photometric and spectroscopic characteristics of55-inch CCFL and LED backlights for LCD-TV applications,”accepted for publication in Journal of the KIIEE.
  4. G. Park, Y. G. Kim, J. H. Yi, J. H. Kwon, J. H. Park,B. G. Kim, B. C. Ahn, and H. S. Soh, “Color mixingcharacteristics of LED backlight unit,” in Proc. IDW ‘07Tech. Digest (Sapporo, Japan, Dec. 2007), pp. 643-646.
  5. Y. G. Kim, G. Park, and J. H. Kwon, “Removal of brightspots and color mixing characteristics of side-lit LEDbacklight,” in Proc. OSK Summer Meeting (PhoenixparkHotel, Korea, Jul. 2008), pp. 443-444.
  6. Y. H. Ju, J.-H. Park, J. H. Lee, J.-Y. Lee, K.-B. Nahm,J.-H. Ko, and J. H. Kim, “Study on the simulation modelfor the optimization of optical structures of edge-lit backlightfor LCD applications,” J. Opt. Soc. Korea 12, 25-30 (2008).
  7. J. H. Lee, Y. H. Ju, J.-H. Park, J.-Y. Lee, K.-B. Nahm,J.-H. Ko, and J. H. Kim, “Optical simulation study on theeffect of reflecting properties of reflection films on theperformances of collimating films for the LCD backlightapplications,” Journal of Information Display 9, 26-32(2008).
  8. J. S. Ryu, M.-Y. Yu, S.-M. Park, S. J. Kim, and J.-H. Ko,“Study on the correlation between the optical performanceof the reflective polarizer and the structure of the backlightfor large-size LCD applications,” New Physics : Sae Mulli60, 56-62 (2010).
  9. B. H. Hong, “Introduction to the analysis and the methodof the luminance improvement characteristics of theinverse-prism sheet,” Information Display 10, 26-33 (2010).
  10. J.-H. Park, J. H. Lee, J. H. Jeong, K.-B. Nahm, and J.-H. Ko, “Optical simulation study on the performances of collimating films for LCD backlight applications,” Hankook Kwanghak Hoeji (Korean J. Opt. Photon.) 18, 432-440 (2007).

Cited by

  1. Study on the Optimization of the Optical Structure of Lenticular-Lens Films for LCD Backlight Applications vol.22, pp.6, 2011,
  2. Optical characteristics of LGP depending on the scattering pattern orientation for flat-type LED lighting vol.23, pp.2, 2016,
  3. Design Guide of Surface and Watertight LED Luminaires for Naval Vessels vol.35, pp.5, 2011,
  4. Optimize pattern design for the thin LGP vol.124, pp.15, 2013,
  5. Effect of Photo Bioreactor with Optical Panel on the Growth Rate of Chlorella vulgaris vol.34, pp.7, 2012,
  6. Design of Light Guide Plate to Improve Optical Characteristics for Large-Area Edge-lit LED Display vol.9, pp.1, 2013,
  7. LGP pattern design with single LED light source vol.125, pp.3, 2014,
  8. Light guide plate with curved V-groove patterns in edge-lit backlight vol.55, pp.1, 2016,