Fringe-field switching technology

Abstract

Fringe-field switching (FFS) liquid crystal display (LCD) mode has been the mainstream for thin-film transistor (TFT) LCDs with superior image quality and low power consumption since the advent of tablet PC like iPad and high-resolution retina mobile displays in 2010. Its application has expanded to displays for automobiles, mobile phones, high-resolution notebooks and monitors, televisions, and also most of the displays that require high-quality images. This chapter first describes switching fundamentals and electrode-structural advantages of the FFS mode for high-resolution and high-aperture displays with the introduction of lowtemperature poly-silicon (LTPS). In recent progress, the FFS mode has interesting features such that the flexoelectric effect arises noticeably when the driving frequency becomes approximately lower than 30 Hz as a power-saving mode. The flexoelectric effect basically gives rise to deterioration in image-quality, causing the so-called image-flickering. Thus, second, this chapter discusses the flexoelectric effect associated with structural conditions and physical properties of liquid crystals and possible solutions to minimise the flexoelectric effects in the FFS mode. Afterwards, superior electro-optic performance and low-power consumption driving of the flexoelectric FFS mode will be discussed in detail, such as light efficiency, high transmittance at the low-frequency driving.