Composite color filters for wide color gamut and high optical efficiency liquid crystal displays

We propose a composite color filter to achieve the wide color gamut and high optical efficiency of liquid crystal display (LCD). The composite color filter comprises a multi-layer polarization interference filter (ML-PIF) and a color filter. Specifically, two crossed polarizers and four twisted nematic liquid crystal layers with alternating opposite twisted directions form the ML-PIF. The Jones matrix method provides the transmittance formula of the ML-PIF. In the experiment, we successfully fabricate the blue and green ML-PIFs samples using the temperature birefringence effect of liquid crystal. When composite color filters (ML-PIF with certain color filters) are used in LCD, this can successfully achieve a color gamut of 122.3% NTSC and an absolute optical efficiency improvement of 1.4%. Alternatively, the composite color filter can attain a color gamut similar to that of a high-performance color filter and an absolute optical efficiency improvement of 3.8%. This composite color filter presents a tremendous opportunity for achieving a wide color gamut and high optical efficiency.