Droplet Size Distribution Effect on the Electro-Optical Properties of Emulsion Type Polymer Dispersed Liquid Crystal

Department of Display Engineering, Hoseo University, Asan 336-795, Korea(Received December 23, 2014; Revised May 7, 2015; Accepted June 9, 2015)Abstract: We established the emulsion method using membrane filter with precise control of LC droplet distribution in PDLC. PDLC cells with various LC droplet size distributions such as single droplet sizes of 1.0 μm, 1.9 μm and 3.5 μm, the mixture of two different LC droplet sizes and the mixture of three different LC droplet sizes were fabricated and the electro-optical properties of the emulsion type PDLC cells with various droplet size distribution were investigated. In the appropriate droplet size range, the PDLCs with the single droplet sizes distributions have good electro optical properties than those with the mixture of three different LC droplet sizes. In addition, the PDLC cells with the mixture of two different LC droplet sizes have the better electro optical properties than those with single droplet sizes distribution. The PDLC cell with dual droplet size distribution of 1.0+1.9 μm shown the best electro optical properties than the PDLC cells with other size distributions. This method enabled us to find the proper LC droplet size distribution for achieving both high transmittance and contrast ratio.Keywords: PDLC, Emulsion, Membrane filter, Droplet size, Flexible ()*+