Brightness management in a direct LED backlight for LCD TVs

Ching Cherng Sun, Ivan Moreno, Shih Hsun Chung, Wei Ting Chien, Chih To Hsieh, Tsung Hsun Yang

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


A method of calculating the luminance and luminance uniformity of a bottom LED backlight is proposed and demonstrated. Both the power consumption and brightness uniformity as a function of screen brightness, screen size, backlight thickness, transmittance of the LCD panel, reflective cavity efficiency, gain, cone angle of the enhancement films, LED array configuration, and the average luminous flux, radiation pattern, and input power of individual LEDs. Moreover, a 42-in. LCD TV using this backlight design approach was fabricated. The bottom backlight incorporates an array of RGGB 4-in-1 multi-chip LEDs within a highly reflective box behind a diffuser and a dual brightness-enhancement film. The brightness uniformity can be predicted within an accuracy of 94% and the luminance level within an accuracy of 96%.

Original languageEnglish
Pages (from-to)519-526
Number of pages8
JournalJournal of the Society for Information Display
Issue number4
StatePublished - Apr 2008


  • Light-emitting diodes
  • Optical engineering


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