Abstract:
A field emission display having emitters controlled by an integrated driving circuit. The field emission display includes a charge shield positioned above exposed areas of the substrate to protect driving circuitry integrated into the substrate. The charge shield is a conductive layer within an insulative layer covering the driving circuit. The charge shield is connected to ground or to a low reference potential to bleed away current within the insulative layer, thereby preventing drifting charges from affecting the electrical response of the integrated driving circuit. The charge shield also terminates electric fields within the insulative layer to reduce the effect on the integrated driving circuit of dynamic variations in surface charge. Electrical characteristics of the driving circuit thus remain constant, reducing variations in the current supplied to the emitters, thereby reducing variations in the intensity of light emitted by the display.
Abstract:
A field emission display (110) of the active matrix type is arranged in rows and columns with a current source (126) for each column. As an active matrix display, each pixel circuit (118) in an array of pixel circuits (116) includes a switch for enabling display by that pixel circuit. By locating the current source (126) outside the array (116), for example outside a contour circumscribing the array when the display is formed on a susbstrate, smaller pixel circuit geometries are achieved.
Abstract:
A semiconductor device for use in field emission displays includes a substrate (30) formed from a semiconductor material, glass, soda lime, or plastic. A first layer of a conductive material (28) is formed on the substrate. A second resistive layer of microcrystalline silicon (32) is formed on the first layer. This layer has characteristics that do not fluctuate in response to conditions that vary during the operation of the field emission display, particularly the varying light intensity from the emitted electrons or from the ambient. One or more cold-cathode emitters (34) are formed on the second layer.
Abstract:
A method for forming resistors for regulating current in a field emission display (10) comprises integrating a high resistance resistor (32) into circuitry for the field emission display. The resistor (32) is in electrical communication with emitter sites (14) for the field emission display (10) and with other circuit components such as ground. The high resistance resistor (32) can be formed as a layer of a high resistivity material, such as intrinsic polycrystalline silicon, polycrystalline silicon doped with a conductivity-degrading dopant, lightly doped polysilicon, titanium oxynitride, tantalum oxynitride or a glass type material deposited on a baseplate (12) of the field emission display (10). Contacts (38, 39) are formed in the high resistivity material to establish electrical communication between the resistor (32) and the emitter sites (14) and between the resistor (32) and the other circuit components. The contacts (38, 39) can be formed as low resistance contacts (e.g., ohmic contacts) or as high resistance contacts (e.g., Schottky contacts).
Abstract:
A method for forming resistors for regulating current in a field emission display (10) comprises integrating a high resistance resistor (32) into circuitry for the field emission display. The resistor (32) is in electrical communication with emitter sites (14) for the field emission display (10) and with other circuit components such as ground. The high resistance resistor (32) can be formed as a layer of a high resistivity material, such as intrinsic polycrystalline silicon, polycrystalline silicon doped with a conductivity-degrading dopant, lightly doped polysilicon, titanium oxynitride, tantalum oxynitride or a glass type material deposited on a baseplate (12) of the field emission display (10). Contacts (38, 39) are formed in the high resistivity material to establish electrical communication between the resistor (32) and the emitter sites (14) and between the resistor (32) and the other circuit components. The contacts (38, 39) can be formed as low resistance contacts (e.g., ohmic contacts) or as high resistance contacts (e.g., Schottky contacts).