Application of Taguchi Method in Light-Emitting Diode Backlight Design for Wide Color Gamut Displays

This paper utilizes the Taguchi design method to optimize the design parameters of a light-emitting diode (LED) backlight unit for wide color gamut liquid crystal displays (LCDs). In optimizing the design, the parametric analyses consider two particular regions of the backlight unit, namely, the color-mixing zone and the extractor zone. The Taguchi experiments are configured in L9 (34 ) orthogonal arrays and are designed to evaluate the effects of the design parameters on the color-difference, optical efficiency and luminance of the unit. The analysis of variance (ANOVA) results reveal that the optical efficiency and color-difference properties are determined primarily by the reflector design and the length of the color mixing zone, respectively, while the luminance to the LCD panel is affected principally by the taper angle of the optical microstructures in the extractor zone. The optimal design parameters of the color-mixing zone and extractor zone are estimated from the Taguchi S/N ratio data and the ANOVA results, and are verified via ray-tracing simulations. For an input flux of 1501 lm, the optimal design shows 0.01 of the color differences in CIE 1976 color space, 85% of the optical efficiency, and 10675 nits of luminance. Thus, the optimized backlight unit provides an ideal solution for the illumination of large-scale LCD display devices.

[1]  P. Clarricoats,et al.  Solution of Maxwell's equations by optimisation (antenna radiation patterns) , 1989 .

[2]  Genichi Taguchi,et al.  Taguchi methods : design of experiments , 1993 .

[3]  Kevin Barraclough,et al.  I and i , 2001, BMJ : British Medical Journal.

[4]  Tony Rodriguez,et al.  Optimized selection of benchmark test parameters for image watermark algorithms based on Taguchi methods and corresponding influence on design decisions for real-world applications , 2003, IS&T/SPIE Electronic Imaging.

[5]  K. Käläntär.  Modulation of viewing angle on an LCD surface through backlight optics , 2003 .

[6]  Simon J. M. Kuppens,et al.  43.3: High-efficiency Slim LED Backlight System with Mixing Light Guide , 2003 .

[7]  Yourii Martynov,et al.  43.4: High Brightness Direct LED Backlight for LCD-TV , 2003 .

[8]  Yingbai Yan,et al.  High quality light guide plates that can control the illumination angle based on microprism structures , 2004 .

[9]  Oliver Dross,et al.  High-efficiency LED backlight optics designed with the flow-line method , 2005, SPIE Optics + Photonics.

[10]  Kye-Si Kwon,et al.  Robust finite element model updating using Taguchi method , 2005 .

[11]  T. L. R. Davenport,et al.  Optimizing density patterns to achieve desired light extraction for displays , 2006, International Optical Design Conference.

[12]  Yi-Chin Fang,et al.  A new design mixing RGB LED (red, green, blue light-emitting diode) for a modern LCD (liquid crystal display) backlight system , 2006, SPIE Optics + Photonics.

[13]  Dong-Woo Lee,et al.  High-efficiency trichromatic LED backlight for mobile LCDs , 2006, SPIE OPTO.

[14]  Paul C.-P. Chao,et al.  Design of a novel LED lens cap and optimization of LED placement in a large area direct backlight for LCD-TVs , 2006, SPIE Photonics Europe.

[15]  이철호,et al.  Back light unit having a light guide buffer plate , 2006 .

[16]  Jee-Gong Chang,et al.  Dot-pattern design of a light guide in an edge-lit backlight using a regional partition approach , 2007 .

[17]  Ching-Cherng Sun,et al.  Direct LED backlight for large area LCD TVs: brightness analysis , 2007, SPIE Optical Engineering + Applications.

[18]  Kai Wang,et al.  A novel highly integrated light guide plate using micro optical technique , 2007, SPIE/COS Photonics Asia.

[19]  William J. Cassarly.  Backlight pattern optimization , 2007, SPIE/COS Photonics Asia.

[20]  H. Öktem,et al.  Application of Taguchi optimization technique in determining plastic injection molding process parameters for a thin-shell part , 2007 .

[21]  I. Fujieda,et al.  Input couplers for thin light-guides and light-emitting diodes , 2008 .

[22]  E. Anawa,et al.  Using Taguchi method to optimize welding pool of dissimilar laser-welded components , 2008 .