Enlarging the colour gamut of LCD with YAG-LED by using a liquid crystal based polarisation interference filter

We proposed a polarisation interference filter (PIF) to enlarge the colour gamut of liquid crystal display (LCD) with YAG-LED backlight, and the PIF consists of two crossed polarisers and two liquid crystal layers. The PIF can be used in the backlight unit to improve the colour gamut of LCD by eliminating unwanted colours in the spectrum. When the PIF is integrated into the YAG-LED backlight, the colour gamut of the LCD can be improved from 84% NTSC to 116% NTSC, and the colour gamut is larger than 116% NTSC within 30° polar angle. When a compensation layer is employed, the colour gamut distribution of LCD is more uniform at full viewing angles. The PIF has great potential for achieving a wide colour gamut display.