Wide Color Gamut Backlight for Liquid Crystal Displays Using Three-Band Phosphor-Converted White Light-Emitting Diodes

This work reports a wide color gamut backlight for liquid crystal display (LCD) utilizing a three-band white light-emitting diodes (LED). The LED backlight was fabricated by combining a blue LED chip with beta-sialon:Eu (green) and CaAlSiN3:Eu (red) phosphors. This 2-phosphor-converted white LED shows a discrete spectrum with distinct separation of red, green, and blue primary colors due to a narrow and asymmetric emission band of the green phosphor. By applying typical color filters of LCDs and color-matching functions, a wide color gamut of 91.9% of the National Television Standard Committee standard is attained, compared to 71.6% for the conventional two-band white LED. (C) 2009 The Japan Society of Applied Physics