Wide color gamut and high dynamic range displays using RGBW LCDs

An increasing number of studies on efficient implementation of vivid and realistic displays are being conducted as liquid crystal displays (LCDs) become widely used in TV applications. For vivid displays, the specifications such as wide color gamut (WCG) and high dynamic range (HDR) should be implemented in LCDs. However, the low transmittance rate of the WCG and the significant costs for the peak luminance capability of the HDR are major obstacles. Hence, an RGBW LCD, which is capable of increasing the transmission efficiency, may be a good platform to overcome these problems. In this paper, we estimate the perceived brightness effect of the WCG by using the Helmholtz-Kohlrausch (H-K) effect on RGB and RGBW LCDs. The simulation results showed that the RGBW LCD was more suitable for adopting the WCG than the RGB LCD in terms of the brightness balance of achromatic and chromatic colors, and the results were also confirmed by subjective tests. In addition, we propose an effective method to implement the HDR display based on the RGBW LCD. The data stretch, considering a local adaptation characteristic of a human visual system (HVS), greatly enhanced the details of the dark regions, and the local peak dimming using the white channel analysis and the white channel data itself increased the expressiveness of the peak luminance in irradiative or specular regions to 1500 nits. (C) 2015 Elsevier B.V. All rights reserved.1165sciescopu