A new technology which enables a local brightness control according to the displayed images has been expected in the thin and lightweight backlight systems to improve a contrast ratio and power consumption of the liquid crystal displays (LCDs). In this paper, we have proposed a novel local-dimming backlight system using alignment-controlled polymer-dispersed liquid crystals as a light-guiding plate and investigated the forming conditions of polymer-dispersed liquid crystals to achieve both a high-luminance ratio and a fast response speed. As a result, we found that a luminance ratio and response speed of the backlight system can be improved by using bifunctional LC monomer materials and forming fine and rigid polymer network in the LCs, and achieved high luminance ratio of 16:1 and fast response time less than 0.5 ms. In addition, we fabricated the twisted nematic-mode LCD using the local dimming light-guiding plate-type backlight based on this design, and successfully realized eight times higher contrast ratio than that of the traditional twisted nematic-mode LCD.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering