Korean Journal of Optics and Photonics (한국광학회지)

Optical Society of Korea (한국광학회)
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Optimized Optical Design of LCD Color-matching BLU Using an RGB Light Source

RGB 광원을 사용한 고효율 LCD Color-matching BLU의 광학적 설계

  • 전화준 (영남대학교 자연과학대학 물리학과) ;
  • 곽진석 (영남대학교 자연과학대학 물리학과) ;
  • 권진혁 (영남대학교 자연과학대학 물리학과)
  • Received : 2019.04.05
  • Accepted : 2019.05.15
  • Published : 2019.06.25
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Abstract

An LCD backlight unit (BLU) using RGB light sources is designed and simulated, in order to improve its optical energy efficiency. A color-matching BLU is designed with a lenticular lens array (LLA) with elements that image the linear RGB light sources onto the RGB subpixels of the color filter. Type-A and Type-B simulations are performed, according to the location of the light sources. As a result, the luminance increases to 210% in Type-A and 270% in Type-B respectively. The optimum values for the height and the gap of the LLA for maximum efficiency are found to be $25{\mu}m$ and $3{\mu}m$ respectively.

LCD의 광 효율을 향상시키기 위해 LCD backlight unit (BLU)의 광원으로 적색, 녹색, 청색의 광원을 사용하였으며, RGB 광은 lenticular lens array (LLA)를 통해 집광되어 각각 컬러 필터의 적색, 녹색, 청색 필터에 색일치되는 조건으로 광이 지나도록 설계하여 시뮬레이션하였다. 광원의 위치에 따라 Type-A와 Type-B 두 가지 방식으로 시뮬레이션을 진행하였으며, 그 결과 LLA를 사용하지 않았을 때와 비교하여 Type-A는 휘도가 210%로 상승하였으며, Type-B는 270% 상승함을 확인하였다. LLA의 최적의 조건은 렌즈의 높이가 $25{\mu}m$, 렌즈 간의 간격이 $3{\mu}m$일 때, 효율이 최대가 됨을 확인하였다.

Keywords

KGHHBU_2019_v30n3_101_f0001.png 이미지

Fig. 1. Schematic structure of the color-matching backlight unit of (a) Type-A and (b) Type-B.

KGHHBU_2019_v30n3_101_f0002.png 이미지

Fig. 2. Ray propagation in the color-matching backlight unit of (a) Type-A and (b) Type-B.

KGHHBU_2019_v30n3_101_f0003.png 이미지

Fig. 3. Energy efficiency enhancement of color-matching backlight unit in terms of the height of lenticular lens.

Table 1. Comparison of efficiency enhancement according to the structure of RGB light sources

KGHHBU_2019_v30n3_101_t0001.png 이미지

References

  1. X. Yang, Y. Yan, and G. Jin, "Polarized light-guide plate for liquid crystal display," Opt. Express 13, 8349-8356 (2005). https://doi.org/10.1364/OPEX.13.008349
  2. F. Yamada, H. Nakamura, Y. Sakaguchi, and Y. Taira, "Sequential-color LCD Based on OCB with an LED Backlight," J. Soc. Inf. Disp. 10, 81-85 (2002). https://doi.org/10.1889/1.1827848
  3. C. H. Lee, "Angularly positioned LED-based spatial-temporal color separation system," Opt. Express 20, 19109-19118 (2012). https://doi.org/10.1364/OE.20.019109
  4. M. J. J. Jak, R. Caputo, E. J. Hornix, L. de Sio, D. K. G. de Boer, and H. J. Cornelissen, "Color-separation backlight for improved LCD efficiency," J. Soc. Inf. Disp. 16, 803-810 (2008). https://doi.org/10.1889/1.2966441
  5. C. G. Son, J. S. Gwag, J. H. Lee, and J. H. Kwon, "Analysis of a color-matching backlight system using a blazed grating and a lenticular lens array," Appl. Opt. 51, 8615-8620 (2012). https://doi.org/10.1364/AO.51.008615
  6. J. H. Kwon, "A color-filterless LCD with RGB LED and lenticular-lens arrays," J. Inf. Disp. 11, 45-48 (2010). https://doi.org/10.1080/15980316.2010.9652118
  7. H. J. Jeon, G. J. Park, J. S. Gwag, J. H. Lee, and J. H. Kwon, "Color-matching liquid crystal display using a lenticular lens array and RGB light sources," J. Opt. Soc. Korea 18, 345-349 (2014). https://doi.org/10.3807/JOSK.2014.18.4.345
  8. Y. Kim and C. S. Ha, Advances in Organic Light-Emitting Device (Trans Tech Publications Ltd, Switzerland, 2008).