Fast Switching of Frequency Modulation Twisted Nematic Liquid Crystal Display Fabricated by Doping Nanoparticles and Its Mechanism

Abstract

The electrooptic characteristics of a twisted nematic (TN) liquid crystal display (LCD) fabricated by doping Ag nanoparticles protected with NLC, 5CB (K-15, Merck) molecules have been investigated, and it is shown that the device exhibits a unique electrooptic response characteristic that is sensitive to the high-frequency components of the operating voltage together with the conventional root-mean-square voltage response. We call this device frequency modulation (FM) TN-LCD. The FM-TN-LCD is switched by switching the frequency of the operating voltage while its amplitude is kept unchanged. As an example, the frequency switched from 20 Hz to 500 Hz or 50 Hz to 2 kHz, and the switching is performed with the time constant of 21 ms for the rising process and 3 ms for the falling process. This device shows a peculiar response to a burst AC square wave, where the decay time is reduced by several times compared to that of an undoped TN-LCD. The mechanism of the FM-TN-LCD is investigated through the study of its dielectric properties.

Dielectric and Electro-Optical Properties of Ceramic Nanoparticles Doped Liquid Crystals

“…Instead of synthesizing a large number of high quality LC compound, doping particles into LCs is a potentially cost effective way to attain these important feachures. The doping of nano particles into liquid crystal has emerged as a fascinating area of research to the application point of view [7][8][9][10]. Liquid crystal dispersions containing various types of nano particles have been developed in the recent years [11,12].…”

Effect of barium titanate nanoparticles of different particle sizes on electro-optic and dielectric properties of ferroelectric liquid crystal

“…decrease of driving voltage and switching time of LC displays. [3,4] The new applications of LC materials in display devices, optical processing, photonics, spatial light modulator and adaptive optics require LC materials with improvised properties but because of the complexity in the synthesis of new liquid crystalline materials with exotic properties, the lowconcentration doping in the LC host is one of the best alternative to enhance their physical properties. The enhanced properties of any LC material mainly depend upon the nature of the doping materials, particle size, shape of particles, concentration and the mutual interaction between nanoparticles and LC molecules.…”

Multiscale models of colloidal dispersion of particles in nematic liquid crystals

“…Their effect, however, may still be significant. For example, gold nanoparticle inclusions [8] have a considerable effect on the liquid crystal hosts: they lower the nematic-isotropic transition temperature [9], increase the switching speed [10], and introduce tunability of the dielectric anisotropy [11]. More recently, gold particles [12,13] and layered structures [14] have been studied for their applications to the creation of tunable metamaterials.…”