Abstract: A compensation circuit for use in a high resolution amplified flat panel for radiation imaging. The circuit includes an amplifier having an input terminal to receive amplified signal charge output on a source line by a selected pixel of the flat panel in response to a gate pulse. The amplified signal charge has a DC bias. Switching means is used to connect the input terminal to a potential voltage source when the amplified charge is received. The potential voltage source includes a magnitude substantially the same as the DC bias but opposite in polarity to offset the DC bias.

Abstract: A method and apparatus of operating a dual gate TFT electromagnetic radiation imaging device wherein the electrical conditions on each pixel are compared after exposure to radiation and during measurement. The pixel charge electrode is preset to a predetermined voltage level prior to radiation exposure so that the pixel may be operated beyond its linear operating range.

Abstract: A source driver for an active matrix liquid crystal display, comprising a sample-and-hold circuit for sampling successive lines of an input video signal, a source follower for applying successive lines of the input video signal sampled by the sample-and-hold circuit to successive source lines of the active matrix crystal display, the source follower being characterized by a predetermined threshold voltage; a reset circuit for resetting the successive source lines after respective ones of the successive lines of the input video signal; and an autozero circuit for cancelling the threshold voltage from the video signal so that variations in the threshold voltage do not affect the video signal applied to the successive source lines.

Abstract: During the formation of a self-aligned thin film transistor (50), the semiconductor material channel layer (58) on the gate insulating layer (56) has a passivation shield (P.sub.S) applied to it aligned with the gate electrode (54). The channel layer is then exposed to a reagent selected to yield a chemical reaction with the portions of the channel layer (58) not covered by the passivation shield (P.sub.S) causing removal of a component of the semiconductor material thereby to change the electrical properties of those portions of the channel layer. In this manner, doped source and drain regions (60, 62) can be formed on opposite sides of the channel having edges that extend to the edges of the gate electrode avoiding any overlap therebetween and reducing the parasitic capacitance of the thin film transistor (50).

Abstract: A method of inhibiting electrostatic discharge damage to an array of semiconductor switches (21) formed on a common substrate and arranged in rows and columns comprises the steps of: during formation of gate lines (24) that interconnect one of the rows and columns of the array, connecting one end of each gate line directly to a shorting ring (52) and another end of each gate line to a shorting ring (56) via a protection element (54); during formation of the source lines (26) that interconnect the other of the rows or columns of the array, connecting one end of each source line directly to a shorting ring (56) and connecting another end of each source line to a shorting ring (56) via a protection element (58); and electrically coupling the shorting rings (52, 56). A semiconductor switch array (21) incorporating electrostatic discharge protection (50) is also provided.

Abstract: A thin-film, flat panel, pixelated detector array serving as a real-time digital imager and dosimeter for diagnostic or mega-voltage X rays or gamma rays, including a plurality of photodiodes (30) made of hydrogenated amorphous silicon arrayed in columns and rows upon a glass substrate (12). Each photodiode (30) is connected to a thin film field effect transistor (52) also located upon the glass or quartz substrate (12). Upper and lower metal contacts (38, 22) are located below and above the photodiodes (30) to provide the photodiodes (30) with a reverse bias. The capacitance of each photodiode (30) when multiplied by the resistance of the field effect transistor (52) to which it is connected yields an RC time constant sufficiently small to allow fluoroscopic or radiographic imaging in real time.