Going beyond the limit of an LCD’s color gamut

• Published in: Light, science & applications science & applications, 2017-09, Vol.6 (9), p.e17043-e17043
• Main Authors: Chen, Hai-Wei, Zhu, Rui-Dong, He, Juan, Duan, Wei, Hu, Wei, Lu, Yan-Qing, Li, Ming-Chun, Lee, Seok-Lyul, Dong, Ya-Jie, Wu, Shin-Tson
• Format: Article
• Language: English
• Subjects: 639/624/1075/146; 639/624/1075/401; Applied and Technical Physics; Atomic; Classical and Continuum Physics; Color; Filters; Lasers; LCDs; Light emitting diodes; Light sources; Liquid crystal displays; Molecular; Optical and Plasma Physics; Optical Devices; Optics; Original; original-article; Photonics; Physics; Physics and Astronomy; Printing industry; Quantum dots
• ISSN: 2047-7538; 2095-5545; 2047-7538
• DOI: 10.1038/lsa.2017.43

In this study, we analyze how a backlight’s peak wavelength, full-width at half-maximum (FWHM), and color filters affect the color gamut of a liquid crystal display (LCD) device and establish a theoretical limit, even if the FWHM approaches 1 nm. To overcome this limit, we propose a new backlight system incorporating a functional reflective polarizer and a patterned half-wave plate to decouple the polarization states of the blue light and the green/red lights. As a result, the crosstalk between three primary colors is greatly suppressed, and the color gamut is significantly widened. In the experiment, we prepare a white-light source using a blue light-emitting diode (LED) to pump green perovskite polymer film and red quantum dots and demonstrate an exceedingly large color gamut (95.8% Rec. 2020 in Commission internationale de l'éclairage (CIE) 1931 color space and 97.3% Rec. 2020 in CIE 1976 color space) with commercial high-efficiency color filters. These results are beyond the color gamut limit achievable by a conventional LCD. Our design works equally well for other light sources, such as a 2-phosphor-converted white LED. Liquid-crystal displays: Broadening the rainbow A liquid-crystal display that produces a wider range of colours than current commercial devices has been created. Shin-Tson Wu from the University of Central Florida and co-workers achieved this by determining the optimal optical characteristics of a liquid-crystal display backlight. Colour liquid-crystal displays work by using a layer of electrically controlled molecules to block emission from a white-light source. The optical properties of this white backlight determine the full range of colours created by the display, referred to as its gamut. Wu and colleagues created a backlight based on a blue light-emitting diode combined with quantum dots and a perovskite polymer film. They then optimized the emission by adding a reflective polarizer and a half-wave plate, and hence increased the gamut of the display.