LED的波長與亮度會隨著本身溫度改變而飄移。亮度的飄移已藉由PWM (pulse width modulation，PWM)的duty cycle大小來補償。波長飄移一般而言並沒有獲得補償。由於不同的LED驅動電流會有不同的發光波長，因此本論文除了調變LED的duty cycle維持其亮度的穩定之外，並嘗試於控制系統中加入LED驅動電流調變。在溫度上升的同時，系統可以即時調變duty cycle與驅動電流來維持背光模組色溫的穩定。我們利用duty cycle的調變來維持亮度的穩定，並隨著溫度的改變來調變LED的驅動電流以減少波長的漂移。
基於以上的即時回授與調變方式，我們可將背光模組的色溫維持在5500K上下。在溫度變化25~45℃時，其最大的色溫差異在64K以內；在CIE1976的色座標圖上的u^'與v^'軸最大的距離差從0.0111與0.0067降低為-0.0017和0.0020。而背光模組的平均色差在色座標圖上的距離∆u^' v^'從0.0115降為0.0008。

The brightness and wavelength of LED will be shifted by temperature change. The brightness shift can be compensated by the duty cycle in pulse width modulation (PWM). But the wavelength shift was not compensated in general. Due to the different driving current of LED has different radiate wavelength, we attempt to modulate the driving current of LED into a control system in this thesis. So, as the temperature increasing, the system can immediately adjust the duty cycle and the driving current to keep the color temperature stable. The objective of this thesis is to utilize the duty cycle modulation to keep brightness stable and change the driving current of LED with temperature to reduce wavelength shift.
Based on the described real time feedback and modulation, we can keep the color temperature of back lighting unit around 5500K. The maximum change of color temperature is less then 64K when the temperature is from 25 to 45℃; the maximum distance of CIE1976 chromaticity diagram in u^' and v^' axis at change from 0.0111 and 0.0067 to -0.0017 and 0.0020. The average color difference of back lighting unit ∆u^' v^', which is the directly distance at chromaticity diagram, change from 0.0115 to 0.0008.

1. J.Y. Tsao, “Solid-State Lighting: Lamps, Chips and Materials for Tomorrow,” IEEE Circuit and Devices Magazine 4, 28-37, 2004.
2. A. Stich, LEDs, New Light Sources for Display Backlighting, Osram Opto Semiconductors, Regensburg, 2004.
3. A. Perduijn, “Light Output Feedback Solution for RGB LED Backlight Applications,” SID 34, 1254-1257, 2003.
4. 林彥男，微米金屬光柵對氮化銦鎵多重量子井發光效率之研究，國立中央大學光電研究所，碩士論文，2007。
5. 溫竣貴，LED背光源整合系統設計之色溫管理，國立交通大學電子與光電學程，碩士論文，2006。
6. 柯俊宇，LEDs發光光譜校正，國立中央大學光電研究所，碩士論文，2004。
7. S. Chhajed, “Junction Temperature in Light-emitting Diodes Assessed by Different Methods,” SPIE 5739, 16-24, 2005.
8. 紀國鐘，液晶顯示器技術手冊，經濟部技術處，2003。
9. A. S. Sedra, Microelectronic Circuits, 4th ed., Oxford University Press, Oxford, 1996.
10. 陳隆建，發光二極體之原理與製程，全華科技圖書股份有限公司，2008。
11. Y. P. Varshni, “Temperature Dependence of the Energy Gap in Semiconductors,” Physica 34, 149-154, 1967.
12. http://zh.wikipedia.org/zh-tw/LED
13. 朱正之，適用於LCD TV之LED背光電源電路之研製，台灣科技大學電子工程系，碩士論文，2006。
14. R. S. West, “High Brightness Direct LED Backlight for LCD-TV,” SID 34, 1262-1265, 2003.
15. D. E. Johnson, Basic Electric Circuit Analysis, 5th ed., Prentice Hall, Upper Saddle River, 1997.
16. Data sheet, Max17061, Maxim Integrated Products, Sunnyvale, 2008.
17. Data sheet, LM3432, National Semiconductor, Santa Clara, 2007.
18. Data sheet, MBI1801, Macroblock, Hsinchu, 2008.
19. 大田登，基礎色彩再現工程，全華科技圖書股份有限公司，2006。
20. R. S. Berns, Billmeye and Saltzman's Principles of Color Technology, John Wiley & Sons, New York, 2000.
21. http://www.ecse.rpi.edu/~schubert/Light-Emitting-Diodes-dot-org/
22. Data sheet, C8051F310, Silicon Laboratories, Austin, 2006.
23. Data sheet, 61-23-R6GHBHC-A01, Everlight Electronics, Taipei, 2007.
24. Data sheet, S6428-30, Hamamatsu Photonics, Iwata, 2008.
25. 盧明智，感測器應用與線路分析，全華科技圖書股份有限公司，2008。
26. 盧明智，線性IC積木式實驗與專題製作，全華科技圖書股份有限公司，2001。
27. Data sheet, Max6648, Maxim Integrated Products, Sunnyvale, 2008.
28. Data sheet, MBI1816, Macroblock, Hsinchu, 2008.
29. 葉振明，電子電路控制與應用，全華科技圖書股份有限公司，2007。