Direct LED backlight for large area LCD TVs: brightness analysis

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

doi:10.1117/12.735508

14 September 2007 Direct LED backlight for large area LCD TVs: brightness analysis

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

Proceedings Volume 6669, Seventh International Conference on Solid State Lighting; 666909 (2007) https://doi.org/10.1117/12.735508
Event: Optical Engineering + Applications, 2007, San Diego, California, United States

Abstract

A direct or bottom LED backlight is a key concept in large area LCD displays because it does not use a light guide, is flat, and is easy to assemble. In this paper, a method of luminance management for a bottom LED backlight is proposed and demonstrated. We analytically calculate both the power consumption and brightness uniformity in function of: screen brightness, screen size, backlight thickness, transmittance of the LCD panel, reflective cavity efficiency, gain and cone angle of enhancement films, LED array configuration, and the average luminous flux and radiation pattern of a single LED. Moreover, a 42-inch LCD television with this backlight design approach is made and demonstrated. 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. We predict with an accuracy of 94% the brightness uniformity and with 96% the luminance level.

Citation Download Citation

Ching-Cherng Sun, Ivan Moreno, Shih-Hsun Chung, Wei-Ting Chien, Chih-To Hsieh, and Tsung-Hsun Yang "Direct LED backlight for large area LCD TVs: brightness analysis", Proc. SPIE 6669, Seventh International Conference on Solid State Lighting, 666909 (14 September 2007); https://doi.org/10.1117/12.735508

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