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http://dx.doi.org/10.3807/KJOP.2010.21.2.061

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

Lee, Jung-Ho (Department of Physics, Hallym University)
Nahm, Kie-Bong (Department of Physics, Hallym University)
Ko, Jae-Hyeon (Department of Physics, Hallym University)
Kim, Joong-Hyun (AMLCD Division, Samsung Electronics Co. Ltd.)
Publication Information
Korean Journal of Optics and Photonics / v.21, no.2, 2010 , pp. 61-68 More about this Journal
Abstract
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.
Keywords
Liquid crystal display(LCD); Backlight; Light-emitting diodes; Light guide plate; Bright spot;
Citations & Related Records
Times Cited By KSCI : 5  (Citation Analysis)
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1 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).   과학기술학회마을   DOI
2 M. Anandan, “LED backlight for LCD/TV monitor: issuesthat remain,” in Proc. SID ‘06 Tech. Digest (San Francisco,USA, May 2006), pp. 1509-1512.
3 A. Mills, “LED backlights poised to penetrate larger liquidcrystal displays,” LEDs Magazine May/June, 36-38 (2007).
4 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.
5 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.
6 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.
7 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).   DOI
8 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).   DOI
9 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).   DOI
10 B. H. Hong, “Introduction to the analysis and the methodof the luminance improvement characteristics of theinverse-prism sheet,” Information Display 10, 26-33 (2010).