Reflective color LCDs with high image quality, which have very low power consumption when displaying still images and can also display moving pictures, have been developed. Two key technologies are Memory‐in‐Pixel (MIP) fabrication using LTPS technology, and another is optical property optimization by adopting a newly‐developed scattering layer.

In this paper, the performance of a new RGBW reflective display for mobile devices is described, including high reflectance and wide color gamut. In addition, a newly developed 7‐inch WUXGA (1200 times 1920) prototype reflective color LCD using a new RGBW technology is described.

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-A 7.03-in. extended graphics array reflective LCD prototype has been developed by using memory-in-pixel (MIP) technologies with a newly designed system and pixel structure. The MIP system comprising a MIP backplane and a display driver has been optimized to reduce power consumption. The MIP backplane has specific circuits that allow accessing row drivers randomly, and the display driver manages which row should be accessed. Thus, the system is capable of showing a mixture of still and moving images, resulting in low power consumption. A dithering block embedded in the display driver enables to select an appropriate dithering algorithm according to the types of images and the position on the screen. In addition, the novel pixel structure, "three divided patterns", has been designed to improve image quality and to provide visibility in dark environments. The latter is based on a novel approach; interpixel area is used for an aperture to transmit light from the backlight, and the fringe field from adjacent pixel electrodes is used to control LC directions. The feature of the pixel structure is also effective for obtaining equivalent gamma between reflective and transmissive images.

We have developed 10-inch RGBW LCD with edge-lit 2D local dimming backlight system for automotive applications. This prototype system has power consumption reduction performance of 41.5% compared to a conventional RGB display without local dimming backlight. The performance and evaluation results are described in this paper. Author KeywordsAutomotive display, RGBW, Local Dimming, LCD, Backlight, Edge-lit, CIE2000 BackgroundThe backlights for automotive displays require high power consumption to obtain high luminance more than 1,000 cd/m2. High-resolution displays, as well as the current mobile displays are expected to be used for automotive in the near future, resulting in increased power consumption. Furthermore, there has been concern about the cost of the heat sink systems to suppress the increase in the temperature of automotive displays. As such, the development of displays with reduced power consumption is becoming increasingly important. Moreover, high-contrast characteristics, especially deep black, are required to achieve unity of interior design. We previously reported the development of an RGBW mobile display with a local dimming system [1] based on the "Extended HSV" color space model [2, 3] to reduce power consumption and obtain a higher contrast ratio. In our previous study [1], LEDs were placed on one side of the LCD module. To obtain over 1,000 cd/m2 luminance for high-resolution automotive displays, LEDs are placed on both sides of the LCD module in this study. Furthermore, a 2D local dimming system can be adapted to suppress increased backlight power consumption, which can achieved by optimizing the previous 1D local dimming algorithm for 2D. Method for Determining LED PWM in 2D