Ferrofluid display device

Abstract

A magnetizable fluid which serves as a display liquid and which includes a suspension of colloidal magnetic particles is used in a display device. The magnetic fluid is opaque to provide optical contrast. A host liquid is substantially immiscible with the display liquid. The display liquid is carried in a reservoir section which is distributed about the periphery of a display field in the reservoir. Each propagation line of the display field is provided with a bubble generator, which passes bubbles by the input end of each line. A bubble switch coil draws selected bubbles across a gap to reach the associated propagation line in response to a signal impressed on the coil. A uniform rotating magnetic field is provided by a permanent magnet beneath the display or by orthogonal magnetic coils.

Dependencies are inferred from the claim text.