Wide gamut LCD using locally dimmable four‐primary‐color LED backlight

Abstract

This paper proposes a wide gamut LCD using locally dimmable four‐primary‐color (4PC) LED backlight. Although the color gamut of LCDs has been improved in recent years, it is insufficient to reproduce all the colors in the real world. The objective of this paper is to propose a wide gamut LCD that reproduces all the colors in the real world while keeping the cost increases to a minimum. We evaluated the color gamut reproduced by LEDs of multiple primary colors and selected cyan as the optimal color to be added to the three primary colors to reproduce all the colors in the real world. Therefore, we designed an LED backlight consisting of an additional only‐cyan LED with three‐primary‐color LEDs and developed a prototype LCD with 4PC LED backlight. Furthermore, we developed a local dimming algorithm for the 4PC LED backlight. As a result, we confirmed that the prototype LCD with the 4PC LED backlight is able to cover almost all the colors in the real world and also able to display natural images with highly saturated colors by local dimming.

Adaptive one-dimensional dimming technique for liquid crystal displays with low power consumption and high image quality

“…[1][2][3][4][5][6] To reduce power consumption while increasing image quality in LCDs, various technologies have been studied such as backlight dimming, [7][8][9][10][11][12][13][14][15] inversion methods, [16][17][18] and charge sharing methods. [19][20][21][22][23][24] Based on a demand for slim designs and low power consumption, a side-lit light-emitting diode (LED) backlight unit (BLU) has been widely adopted not only in mobile LCD applications but also in large LCDs.…”

“…[19][20][21][22][23][24] Based on a demand for slim designs and low power consumption, a side-lit light-emitting diode (LED) backlight unit (BLU) has been widely adopted not only in mobile LCD applications but also in large LCDs. [9][10][11][12][13][14] To further reduce power consumption in LCDs, a dimming technique was developed. Dimming techniques can be generally categorized as three types: zero-dimensional (0-D), one-dimensional (1-D), or two-dimensional (2-D) dimming techniques.…”

Adaptive charge sharing method for liquid crystal displays with lower power consumption

“…Power consumption in liquid crystal displays (LCDs) is currently the subject of intensive research. [1][2][3][4][5][6][7] To achieve lower power consumption with higher image quality in LCDs, various techniques have been studied, including backlight dimming technologies, [8][9][10][11][12][13][14][15] inversion methods, [16][17][18] and charge sharing (CS) methods. [19][20][21][22][23][24][25] Column inversion provides very low power consumption because only one polarity change occurs per frame.…”

Thermal management of edge‐lit wide color gamut backlight for LCD using red laser diodes and cyan LEDs

“…One is to heighten the purity of each primary color and the other is to increase the number of primary colors. Research on increasing the number of primary colors for LCDs has taken place so enthusiastically [5][6][7] that it resulted in the development of a four-primary-color liquid crystal television display in 2010, where increasing the aperture ratio improved the light transmissivity of the liquid crystal cells by 20% compared with a conventional one. 8 Successfully dealing with image signals of significantly wide color gamut such as those defined in the BT.2020 makes it of the utmost importance to increase the color purity of the light sources.…”