Title page for etd-0825111-130535


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URN etd-0825111-130535
Author Chao-Hsuan Huang
Author's Email Address No Public.
Statistics This thesis had been viewed 5338 times. Download 1381 times.
Department Electrical Engineering
Year 2010
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Implementation of Double Pulse Width Modulation for Uniformity of LED Light Bars in LCD Back-Light
Date of Defense 2011-06-10
Page Count 55
Keyword
  • Dimming
  • Back-Light
  • Light Emitting Diode (LED)
  • Double Pulse Width Modulation (DPWM)
  • Abstract This thesis proposes a dimming approach with Double Pulse Width Modulation for equalizing the light output of the back light with light emitted diodes (LEDs) for large scale outdoor liquid crystal displays (LCDs). The approach compensates the difference among the LED light bars by adjusting the power outputs of converters according to the feedback of light strength from light sensors. With the proposed Double Pulse Width Modulation method, local brightness adjustment on the light bars can be made to provide a uniform light output and the dimming function for LCD can be retained. Experiments results made on a 46” LCD with four LED light bars demonstrate that the double pulse-width- modulation can provide uniformly in the light bar output. The experimental results show the proposed Double Pulse Width Modulation  (DPWM) method can alleviate the problem from divergence of the light bars and thus can generate more uniform light output on LCDs.
    Advisory Committee
  • Chih-Chiang Hua - chair
  • Jia-You Lee - co-chair
  • Ching-Ran Lee - co-chair
  • Yao-Ching Hsieh - co-chair
  • Chin-Sien Moo - advisor
  • Files
  • etd-0825111-130535.pdf
  • indicate access worldwide
    Date of Submission 2011-08-25

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