A Direct-View Backlight With UV Excited Trichromatic Phosphor Conversion Film

This work presents a novel ultraviolet (UV) excited flat lighting (UFL) system consisting of remote phosphor converter (RPC) for liquid-crystal display (LCD) backlight applications. A trichromatic RPC is excited using 254 nm UV lamps to achieve a slim, high color saturation and high luminance backlight. Experimental results indicate that the module thickness reduces to 14.5 mm, along with a high color saturation (92% of the NTSC standard) as well as a high luminance (573 cd/m² ) when applied to large sized display (42-inch). Additionally, the proposed UFL backlight configuration has already been certified by a lifetime test to ensure the feasibility of proposed system in mass production.

I. Introduction

Direct-view backlight (BL) is especially useful for large TFT-LCD applications in terms of high power efficiency and high luminance in contrast with edge-view BL. The conventional configuration of a direct-view BL set generally consists of a metal holder with plural light sources, e.g., CCFL and LED, inside and a diffuser plate above the light source to effectively suppress the non-uniform luminance distribution. The BL design (Fig. 1(a)) with either a CCFL or LED light source lacks a slim configuration. According to Fig. 1(b), despite the edge-view BL sets to thin the BL outline, LED light source with inadequate color saturation, LED color binning and thermal effect are still the issues for commercialization purposes [1]–[9].