Abstract: A display overlay includes a contrast media layer and a photoconductive layer disposed between two electrodes. Light from an emissive display strikes the photoconductive layer and lowers the impedance of the photoconductive layer at the point at which the light is incident. Voltage applied to the electrodes creates an electric field that addresses the contrast media layer in locations of reduced impedance.

Abstract: Novel addressing schemes for controlling bistable electronically addressable displays include the use of addressing signals with additional signals having opposite polarity and equal integrated signal strength, and addressing schemes that minimize the number of state changes that a display element undergoes. In one embodiment, pre-pulses are employed to apply a pre-stress to an display element that is equal and opposite to the electrical stress applied in addressing the element. In another embodiment, the addressing signal is followed by a post-stressing pulse. Methods for minimizing the number of display elements that must change state to change the image displayed include the determination of a set of elements that must be deactivated and a set of elements that must be activated to change the image depicted by a display. Alternatively, only the elements forming one image are deactivated before the elements forming a different image are activated.

Abstract: A mounted display assembly comprises a flexible substrate that supports both display elements and control circuits. The display assembly generally comprises: an electrical connection formed on the flexible substrate, the electrical connection having first and second contact pads; a display element in electrical communication with the first contact pad; and a control circuit mounted on the flexible substrate and in electrical communication with the second contact pad. In a preferred embodiment, the display element comprises a microencapsulated electrophoretic display medium. In another preferred embodiment, printing processes are employed in manufacturing methods for the display assembly.

Abstract: A portable electronic device, for example a cellular telephone or a personal digital assistant, has an internal screen for the display of information, the electronic device also having an external screen arranged to receive information from the electronic device and being capable of displaying this information on an electro-optic medium. There is also provided a cellular telephone having a visual indicator comprising an electro-optic medium having at least two different display states, the electro-optic medium being arranged to change its display state when a call is received by the telephone.