US Patent 7324262 Optical shutter and light scanning apparatus employing the same

An optical shutter includes a cell having a transparent panel and a hydrophobic transparent insulation panel which are arranged to face each other, a transparent electrode formed on an outer surface of the hydrophobic transparent insulation panel, and an opaque droplet contained in the cell and contacting an inner surface of the hydrophobic transparent insulation panel, wherein the amount of light transmitted is adjusted by changing a contact angle of the opaque droplet with respect to the hydrophobic transparent insulation panel. The opaque droplet may be hydrophobic or hydrophilic. The contact angle of the opaque droplet may be changed by applying an electric field between the transparent electrode and the opaque droplet.