Abstract A display system which responds to a light image to form a viewable image. The system is sealed and is filled with a fluid carrying a dilute suspension of electrically photosensitive particles between two conductive plates. If an image is focused onto the space between the plates and a voltage established therebetween, the particles in contact with the inner surface of the conductive plates will migrate from light-struck areas of the plates. After the fluid has been circulated for an appropriate time after imaging, the fluid circulation is directed through a filter, which replaces the fluid between the plates with fluid having the undeposited particles removed. Various provisions for viewing the images formed within the display system are described.
The method as defined in claim 1 further including the step of erasing the particle image formed on said transparent conductive plate, said erasing step comprising: illuminating said particle image while applying an electric field between said plates of a polarity to remove said particles from said transparent conductive plate, and recirculating said fluid suspension between said plates.
Claim 2
Dependent Claim
37 words
The method as defined in claim 1 wherein particle migration is accomplished by reversing the direction of the electric field between the plates causIng the particles which were not struck by light to migrate from said surface.
Claim 3
Dependent Claim
24 words
The method as defined in claim 1 wherein said electrically photosensitive particles are charged before being directed between said pair of electrically conductive plates.
Claim 4
Dependent Claim
43 words
The method as defined in claim 4 further including the steps of: reducing the electric field between said conductive plates to a valve which inhibits the particles from migration during exposure, and increasing the electric field after image exposure to enable particle migration.