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Improved electro-optical properties of dye-doped polymer dispersed liquid crystal display

FARZANA AHMAD1, JIN WOO LEE2, YOUNG JAE JEON1,* , MUHAMMAD JAMIL3,4

Affiliation

  1. LCD Research Center, Department of Chemistry, Konkuk University, Seoul 05029, Korea
  2. Display R&D Team, LIVICON Co., Ltd., Daesowon-Myeon, Chungbuk, Korea
  3. Division of Global Business, Konkuk University, Seoul 05029, Korea
  4. Department of Physics, Konkuk University, Seoul 05029, Korea

Abstract

The next generation polymer dispersed liquid crystals (PDLCs) based electro optical devices could be polarizer-free flexible and reflective just by doping the dichroic dye material in such devices. The electro-optical performances of both scattering (Off state) and electrically absorbing On state of dye-doped PDLC depend on the curing properties and compositions of dye mixture that control the contrast ratios and domain sizes of polymer networks. Due to having polymer networks that surrounds the LC droplets such electro-optical devices are flexible. In the present work, a dichroic black dye S428 is utilized in PDLC system to make it colored with enhanced contrast ratio properties. Three types of PDLC devices with cell thickness of 20μm are fabricated by different LC and Polymer contents. The doping contents of dye have been varied from 0.5 to 1.5 wt% into the PDLC films. The dye S428 (1.5 wt%) has exhibited smaller domain size PDLCs consisting the ratios of LC/Polymer 77:23 wt% and has indicated the higher contrast ratio and lower operational voltage. This dye can be a distinctive addition in dye doped PDLCs for optical applications..

Keywords

Polymer Dispersed Liquid Crystal films, Opto-electronic devices, Liquid Crystals, Phase separations, Dye doped PDLC.

Submitted at: Dec. 12, 2016
Accepted at: June 7, 2017

Citation

FARZANA AHMAD, JIN WOO LEE, YOUNG JAE JEON, MUHAMMAD JAMIL, Improved electro-optical properties of dye-doped polymer dispersed liquid crystal display, Journal of Optoelectronics and Advanced Materials Vol. 19, Iss. 5-6, pp. 309-313 (2017)