Introduction

ETD refers to components that use colloidal-based nanoparticles to adjust transparency according to the intensity of external electric field. ETD material is commercially available in  colloidal form as ETD-Ink, and ETD-Capsule, which is manufactured by forming ETD-Ink into capsules with an optically transmissible medium. Transparent controllable film (ETD-Film) can be manufactured by uniformly coating ETD-Capsules or filling micro-cups with ETD-Ink.
Organic-inorganic hybrid nanoparticles of core/shell types are uniformly dispersed in a non-aqueous medium, and the alignment of nanoparticles in ETD is varied according to the intensity of external electric field to adjust the transparency. Since transparency and translucency can be easily controlled at a low DC voltage, ETD is an outstanding solution for smart windows that offer variable transparency and smart walls capable of adjusting the amount of sunlight into the building.
ETD's ability to control transmittance can also be used effectively in novel reflective displays and electronic shutter applications.