藉由最佳化LED排列方式增進背光源LED波長使用範圍之模型

Optimization of LED Arrangement for Extending LED Binning Range in Backlight System

周秉彥(Ping-Yen Chou)

指導教授 ： 黃乙白

國立交通大學/電機學院/光電工程系所/碩士(2012年)

https://doi.org/10.6842/NCTU.2012.00523

摘要

薄型化液晶電視(Slim format LCD-TV)逐漸成為顯示器市場趨勢，此外，因為發光二極體(LED)具有高能量萃取效率、較長使用壽命、不需使用含汞元素和符合綠色能源需求，LED被視為是下一世代背光源的主流。基於製程上的因素影響，整面晶元(wafer)做出來的所有LED，各項品質和參數會有些許不同，可以根據光波長、光強度和操作電壓來分類，然而，LED在背光源的使用上，波長的挑選是非常苛刻的，導致目前面臨LED無法有效利用、背光源成本無法降低的問題。
本篇論文提出一套分析背光源光學特性系統，來使LED能被運用的更有效率。這套系統的操作原理，首先，需要量測單一光源的光線擴散軌跡(Light spread function)與頻譜(spectrum)資訊，再藉由計算光輝度分布、頻譜線性疊加與色彩座標轉換的模擬程序，來獲得整面背光源色彩均勻性及色偏量的結果。此系統的準確度，已經由比對模擬結果與實際成品來獲得驗證，在展示品中，使用了外層螢光發光技術(Remote phosphor technology)，此結構具備厚度薄、壽命長和光源種類可用範圍廣的優點。藉此分析背光源光學特性系統，可輕易獲得不同條件下的背光色偏量，再加以設計可達降低生產成本與光源有效利用的目的。

關鍵字

直下式背光系統 ； 色彩均勻度 ； LED最佳化排列

並列摘要

Slim-format LCD-TV had been a trend for the current display market. Moreover, light-emitting diode (LED) is expected to become the backlight source of next generation, because of enhanced energy efficiency, a lager lifetime, the omission of mercury, and compliance with demand for green technologies. Since the manufacturing effect, LEDs are classified to different bin types by wavelength, brightness and voltage. However, the wavelength requirement of LED is very strict in backlight system. Therefore, LED cannot be used effectively in backlight systems, which still have high costs, currently.
In this thesis, an analysis method was developed to calculate the optical properties of direct-emitting backlight systems, which expands the usage of bins. The method based on computing the radiance distribution from the measured light spreading function and spectrum of LED. The calculation procedure includes linear spectral superposition and color difference evaluation. The accuracy of this method was verified by a real backlight module, which introduced the remote phosphor backlight system. This structure could have more benefits than the traditional one, including thinner thickness, longer life time, and wider LED bins. The conditions of acceptable color deviation values could be simply obtained, and the different binned LEDs could be efficiently used to reduce cost and achieve the wider binned-LEDs application purpose.

並列關鍵字

direct-emitting backlight ； color uniformity ； optimization of LED arrangement

參考文獻

[2] Dawson, R.M.A. et al, “The impact of the transient response of organic light emitting diodes on the design of active matrix OLED displays”, IEDM '98 Technical Digest, p.875 (1998)

[3] W. B. Choi et al, “Fully sealed, high-brightness carbon-nanotube field-emission display”, Applied Physics Letters, Vol. 75 (1999)

[4] J. I. Pannkove, “Display Devices (Topics in Applied Physics)”, Chap.4, Springer-Verlag (1980)

[5] E. Lueder, Liquid Crystal Displays, John Wiley & Sons, p.294 (2000)

[6] H.-T. Huang, C.-H. Hung, Y.-P. Huang, C.-H. Tien, C.C. Tsai, H.-P. D. Shieh, J. Lin, J. Chen, P. Chen, and W.-C. Chang, “UV Excited Flat Lighting (UFL) System for LCD-TV Backlight Application,” SID’08 DIGEST, p.862-p.865 (2008)