Further improvement of the light efficiency of LCDs via the asymmetric reflection of metallic nanowire gratings

Abstract

Metallic nanowire gratings have been proposed for use as transmitted-type non-absorptive colorfilters and polarizers that take the place of the conventional absorptive ones in liquid crystal displays (LCDs), which can improve the light efficiency by recycling the reflected lights. To achieve a high recycling rate, the designed reflected light should be as high as possible, meaning absorption should be as low as possible. In this work, we find that higher reflection and lower loss can be obtained for the light incident to the grating side than to the substrate side in bi-layered aluminum nanowire gratings (BANGs), by decreasing light localization and waveguiding loss in the substrate. Taking full advantage of the reflection characteristics, we firstly demonstrate that when a BANG-based integrated polarizer and colorfilter is placed with its grating side facing the backlight in LCDs, more than a 30% light enhancement is obtained than the case with the substrate side facing the backlight. This work affords an essential guide for the design of eco-displays by using MNGs.