Oleg Belik

44.5: Dynamic Wide‐Color‐Gamut RGBW Display

LCD displays with an additional white primary (RGBW displays) have some clear advantages over conventional RGB displays. Firstly, they can transmit 50% more light and secondly they can have 50% more resolution compared to a conventional RGB display. RGBW displays also have a clear disadvantage; the display gamut does not match with the standard three-primary (RGB) input gamut. Up to now, this resulted in rather poor color rendition of such displays, which prevented mass-introduction in the (high-end) LCD-TV market. This paper presents the Philips Dynamic Gamut concept that solves the color rendition issues and describes the technical details of a 26″ demonstrator that proves the concept.

Color‐breakup evaluation of spatio‐temporal color displays with two‐ and three‐color fields

— Spatio-temporal color displays have higher transmission and resolution than conventional LCDs, but suffer from color breakup. In this paper, a 120-Hz display with two-color filters and two-color fields is described and the amount of color breakup is compared with that of a 180-Hz full-color-sequential display with no color filters and three-color fields. The results indicate that color breakup in a color-filterless display is annoying, whereas it is just visible in displays with two-color filters even though the refresh rate is much lower.

25.3: Spectrum Sequential Liquid Crystal Display

Conventional displays cannot show all real-world colours. We have made a 30-inch Spectrum Sequential LCD that uses two different types of fluorescent lamps that alternately illuminate the panel. In this way, a 6 primary display is obtained with a 22% larger colour gamut, without modifying the panel itself.

Computation of minimal RGB LED backlight intensity for RGBW LCD displays

In the article we address the problem of RGB LED backlight power minimization in RGBW LCD displays. The problem is formalized as the determination of the minimal LEDs currents (and/or duty cycle) that allows the picture content rendering without clipping artifacts. We will write this problem in mathematical language and show that it has a unique solution. Then we propose an efficient algorithm that finds the minimal LEDs drive values according to the input content. The algorithm is stable and relatively simple. It gives temporally consistent solutions and converges to the minimal gamut in two-three iterations. When used in an RGBW display the method significantly reduces power consumption without clipping in the content.