Optical Simulation Study on the Effect of Reflecting Properties of Reflection Films on the Performances of Collimating Films for the LCD Backlight Applications

  • Lee, Jeong-Ho (Department of Physics, Hallym University) ;
  • Ju, Young-Hyun (Department of Physics, Hallym University) ;
  • Park, Ji-Hee (Department of Physics, Hallym University, Student Member, KIDS) ;
  • Lee, Ji-Young (Department of Physics, Hallym University, Student Member, KIDS) ;
  • Nahm, Kie-Bong (Department of Physics, Hallym University) ;
  • Ko, Jae-Hyeon (Department of Physics, Hallym University, Member, KIDS) ;
  • Kim, Joong-Hyun (AMLCD Division, Samsung Electronics Co. Ltd. Member, KIDS)
  • Published : 2008.03.31

Abstract

The dependence of optical performances of collimating films such as prism films and pyramid films on the reflecting properties of reflection films were investigated by using a ray tracing technique. The angular distribution of the luminance and the on-axis luminance gain were obtained by using a simple backlight model composed of a reflection film, a virtual flat light source, and a collimating film. Three kinds of reflecting properties were used, which were a perfect Lambertian reflector, a perfect mirror reflector, and a reflector having both diffuse and specular properties. It was found that the on-axis luminance gain was the highest in the simulation where a mirror reflector was used, while the viewing angle was the widest where the Lambertian reflector was used. This result indicates that it is necessary to optimize the simulation condition such as the reflecting properties in order to predict the optical performances of collimating films accurately. Quantitative correlation between the optical characteristics of collimating films and the reflecting properties of reflection films can be used to improve simulation technique for the development and the optimization of collimating films for LCD backlight applications.

Keywords

References

  1. M. Anandan, SID '02 Seminar Lecture Notes, (Society for Information Display, San Jose, 2002), p.169
  2. J. -H. Ko, Asian J. Phys. 14, 231 (2005)
  3. R. H. Wilson, P. Guiguizian, J. Lee, R. J. Sudol, and D. R. Strip, in SID '06 Digest, (2006) p.1332
  4. W.-G. Lee, J. H. Jeong, J.-Y. Lee, K. -B. Nahm, J. -H. Ko and J. H. Kim, J. Information Display 7, 1 (2006) https://doi.org/10.1080/15980316.2006.9651991
  5. M. F. Weber, C. A. Stover, L. R. Gilbert, T. J. Nevitt, and A. J. Ouderkirt, Science 287, 2451 (2000) https://doi.org/10.1126/science.287.5462.2451
  6. J. Ha, J. Paek, T. Jang, and J. Choi, in SID '07 Digest, (2007) p.46
  7. M. Tjahjadi, G. Hay, D. J. Coyle, and E. G. Olczak, Information Display 10, 22 (2006)
  8. M. H. Lee, W. T. Moon, M. J. Kim, S. K. Lee, J. S. Yoon, Y. H. Jung, B. K. Jung, H. S. Soh, and B. C. Ahn, in SID '06 Digest, (2006) p.503
  9. J. -H. Park, and J. -H. Ko, J. Opt. Soc. Kor. 11, 118 (2007) https://doi.org/10.3807/JOSK.2007.11.3.118
  10. J. -Y. Lee, Y. -J. Kim, K. -B. Nahm, and J. -H. Ko, in IMID '06 Digest, (2006) p.1343
  11. J. -Y. Lee, K. -B. Nahm, J. -H. Ko, and J. H. Kim, in IDW '06 Digest, (2006) p.941
  12. J.-H. Park, J. H. Lee, J. Ha Jeong, K. -B. Nahm, J. -H. Ko, and J. H. Kim, Hankook Kwanghak Hoeji 18, 432(2007) https://doi.org/10.3807/HKH.2007.18.6.432
  13. J. C. Stover, Optical Scattering: Measurement and Analysis (McGraw-Hill, New York, 1990), Ch.1
  14. J. E. Harvey, Light-Scattering Characteristics of Optical Surfaces (Ph.D. Dissertation, University of Arizona, 1976)