Patent ID: 6284352
Filing Date: 2001-09-04
Classification: G02B,G09F,Y10S,Y10T

Abstract:
A bistable electric paper, comprising:a base substrate layer;a transparent cover layer; andan intermediate layer defining an array of print cells, each print cell including a first completely hidden reservoir adjacent the base substrate layer, a second visible reservoir adjacent the transparent cover layer and visible through the transparent cover layer, a passageway defined between the first completely hidden reservoir and the second visible reservoir shaped to prevent viewing of the completely hidden reservoir when looking through the transparent cover layer, and a ferrofluidic coloring fluid contained in one of the first completely hidden reservoir and the second visible reservoir,wherein a size of the passageway and at least one of a surface tension and a viscosity of the ferrofluidic coloring fluid are selected such that the ferrofluidic coloring fluid does not flow through the passageway absent an external magnetic driving force, but upon application of an external magnetic driving force near one of the base substrate layer and the cover layer, the ferrofluidic coloring fluid from each desired print cell is pulled by the external magnetic force from a farther one of the first hidden reservoir and the second visible reservoir through the passageway and into a nearer one of the first hidden reservoir and the second visible reservoir to form a desired viewable image in the electric paper.