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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

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.

Acknowledgement

Supported by : (주)지엘에스

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