Local Luminance Boosting of an RGBW LCD

Compared to a conventional RGB LCD, an RGBW LCD is known to result in 50% higher light transmission. However, the reduced aperture for the RGB subpixels lead to reduced luminance for saturated pixels. Consequently, colorful images may appear dull due to a lack of sufficient luminance. In this work it is proposed to address the luminance shortage for bright saturated pixels by boosting a spatially modulated backlight. Whereas best-in-class methods for deriving backlight drive levels either results in high contrast or temporal stability, we propose a reformulation which provide superior contrast and temporal stability. By employing local backlight boosting, the 99.5% percentile of ΔE₉₄ is reduced from 12.3 JND to 4.3 JND on average. Power consumption is reduced by 18% compared to an RGB LCD with local backlight dimming. Additionally, we propose to increase luminance of desaturated pixels in regions of backlight boosting, which results in an average luminance increase of 16% for pixels which are boosted.