A novel diffractive backlight concept for mobile displays

Abstract

Abstract— Power‐efficiency demands on mobile communications device displays have become severe with the emergence of full‐video‐capable cellular phones and mobile telephony services such as third‐generation (3G) networks. The display is the main culprit for power consumption in the mobile‐phone user interface and the backlight unit (BLU) of commonly used active‐matrix liquid‐crystal displays (AMLCDs) is the main power drain in the display. One way of reducing the power dissipation of a mobile liquid‐crystal display is to efficiently distribute and outcouple the light available in the backlight unit to direct the primary wavelength bands in a spectrum‐specific fashion through the respective color subpixels. This paper describes a diffractive‐optics approach for a novel backlight unit to realize this goal. A model grating structure was fabricated and the distribution of outcoupled light was studied. The results verify that the new BLU concept based on an array of spectrum‐specific gratings is feasible.