Ultra-Thin Design of Large Backlight Module Used in Illuminating Advertising Pictures


Article Preview

At present, the large backlight modules, used in illuminating advertising pictures, are designed and developed in various specifications, whose common goal is to try to manufacture thinner backlight modules and produce more uniform illumination. The currently well developed backlighting technology for liquid crystal displays (LCDs) can be transformed and used in such an area. However, the design of edge-lit backlight with size of over 1 square meter has great difficulties in eliminating the phenomenon of non-uniform illumination. In this paper, the application of Bezier curve in the simulating the dot pattern on the bottom of light guide is presented, which directly determines the final light extraction efficiency and illuminating uniformity. Taking the RMS deviation of illuminance values at several sample positions as the merit function, the shape of Bezier curves can be smoothly changed, so that the dot radius can be optimized in a fast and efficient way. Such an optimization procedure uses only two variables and has a fast convergence. As an example, a large light guide, 800mm×1000mm in size, was designed by applying the Bezier method, and the final uniformity of 70% was achieved. The most prominent feature in such a method is that the thickness of designed light guide can decrease to 5 mm. In sum, the large sized edge-lit backlight can be designed in a short optimization period by simulating the dot radius distribution in a shape of the Bezier curve.



Key Engineering Materials (Volumes 364-366)

Edited by:

Guo Fan JIN, Wing Bun LEE, Chi Fai CHEUNG and Suet TO




S. T. Deng et al., "Ultra-Thin Design of Large Backlight Module Used in Illuminating Advertising Pictures", Key Engineering Materials, Vols. 364-366, pp. 800-804, 2008

Online since:

December 2007




[1] K. Kashima, N. Yoshida, O. Shoji, E. Yanagi, and T. Fukunishi, Back lighting device for a panel, " U.S. Pattern 5, 093, 765. (1992).

[2] K. Kalantar, S. Matsumoto, and T. Onishi, Functional light-guide plate characterized by optical micro-deflector and micro-reflector for LCD backlight, IEICE Transactions on electronics. Vol. 11 (2001), pp.1637-1646.

[3] M. Sendova, Optimized highly efficient large area modular flat panel display lighting device, U.S. pattern 6, 132, 053, (2000).

[4] Tagaya A, Koike Y, Highly scattering optical transmission polymers for bright display, Macromolecular symposia, Vol. 154 (2000), pp.73-82.

DOI: https://doi.org/10.1002/1521-3900(200004)154:1<73::aid-masy73>3.0.co;2-z

[5] Okumura T, Tagaya A, Koike Y, Horiguchi M, Suzuki H, Highly-efficient backlight for liquid crystal display having no optical films, Applied physics letters, Vol. 13 (2003), pp.2515-2517.

DOI: https://doi.org/10.1063/1.1613051

[6] J.G. Chang, Y.B. Fang, C.F. Lin, Solution strategy of optimal dot pattern design for light guide using in backlight, Optical design and fabrication, Proc. Of SPIE Vol. 6034 (2006).

DOI: https://doi.org/10.1117/12.668113

[7] G. Farm, Curves and Surfaces for Computer Aided Geometric Design: A practical Guide, Academic Press, (1996).