Polymer dispersed liquid crystal (PDLC) has been developed for a light shutter due to the advantage of high transmittance. To achieve high transmittance in PDLC's transparent mode and high opacity in shading mode, the black dye-doped emulsion type of PDLC using a membrane filter was investigated with variations in LC droplet size and LC layer thickness. The transmittance difference (Delta T) between the on and off states strongly depended on LC droplet size, and there existed an optimal value to provide higher Delta T, which implies that our method is an effective one for PDLC with a high Delta T.