Progress of LED backlights for LCDs

Abstract

Cold-cathode fluorescent lamps (CCFLs) are being used for LCD backlighting and is currently the dominant technology for LCD backlighting. However, recent attention has been given to LEDs as light sources for LCD backlighting because of their (i) long life, (ii) low-voltage operation, (iii) fast response time, and (iv) wide color gamut. This review article commences with the basics of LEDs as light sources and their limitations, followed by various backlight structures employing LEDs in cell phones, notebook computers, and LCD TVs. The description of the improvement in image quality on an LCD screen, stemming from the characteristics of LEDs, is also given. In conclusion, the possible rapid growth of LED backlights is outlined, thus gradually ending the domination of CCFL backlights.

Secondary electron emission and glow discharge properties of 12CaO·7Al2O3electride for fluorescent lamp applications

“…Although light-emitting diodes (LEDs) are being used for these purposes [2], CCFLs still have several advantages such as large-area illumination and low cost. However, the luminous efficacy of CCFLs is limited mainly by the discharge properties of the cathode electrode.…”

Paper No 9.4: Heat Dissipation Performance of Laser Backlight for Liquid Crystal Television Displays

“…The service life of the LED normally exceeds 50,000 h [2]. Also, since its blue uses a GaN material system similar to a blue LD, the temperature characteristics of the blue LED is relatively good [8].…”

“…Since white LEDs have high wall-plug efficiency (WPE), they are effective in reducing the electric power consumption of displays. However, it is known that the white LED where a blue LED excites the yellow emitting phosphor develops weak spectral intensity over green to red, thus making it have a narrow range of color reproducibility [2].…”

Modeling Power-Constrained Optimal Backlight Dimming for Color Displays

“…Light sources can be placed behind or at the sides of the diffuser, respectively defining direct-lit and edge-lit backlights. Today, light-emitting diodes (LEDs) are replacing cold cathode fluorescent lamps (CCFLs) as light sources, thanks to rapidly improving energy efficiency and decreasing price [1]. LED-based backlights can be divided in independently adjustable segments, called local backlights, in contrast to global backlight, where a single segment covers the Manuscript whole display; in this work we often use the word LED to refer to backlight segments.…”