Abstract: A method of utilizing a thin film device as a photosensor. The thin film device comprises a substrate upon which is deposited a charge transport layer, first and second injecting electrodes in low electrical resistance contact with the charge transport layer, the injecting electrodes being laterally spaced from one another, a gate electrode spaced normally from the first and second injecting electrodes and located opposite the first injecting electrode, for controlling injection therefrom, and laterally offset from the second injecting electrode, and a gate dielectric layer separating the gate electrode from the first and second injecting electrodes and the charge transport layer.

Abstract: An electrostatic discharge protection network for large area transducer arrays in which each transducer has associated therewith an addressing circuit for changing the state of the transducer element. Each addressing circuit includes at least one thin film transistor having a resistive path provided between the thin film transistor gate electrode and one or both of the transistor's other two terminal electrodes in order to provide current leakage paths for equalizing the potential between the gate electrode and the other two terminals during electrostatic discharge.

Abstract: A marking array for use in an ionographic marking apparatus in which the ion modulation structure is subject to a lighly corrosive atmosphere. Improved marking electrodes are provided which comprise a thin film body of a conductive material having a surface which is chemically neutral to the corona effluents.

Abstract: A high voltage amorphous silicon thin film transistor including a gate electrode which controls the injection of charge carriers from a superimposed n+ doped amorphous silicon source electrode into an amorphous silicon charge carrier transport layer, spaced from the gate electrode by a dielectric layer, for causing current conduction through the transport layer to a laterally offset drain electrode. The source electrode is in charge injecting contact with the transport layer and the drain electrode is in collecting contact with the transport layer.

Abstract: An ionographic marking apparatus capable of multifunction operation for use as an input printer, a document copier or a document scanner. The apparatus includes a writing head comprising thin film elements including ion modulating electrodes, data and address lines, and self-biasing amplification circuits including thin film transistors, resistors and photosensors integrally fabricated upon a large area substrate.

Abstract: A thin film writing head for recording information upon a record medium by means of a continuous writing process. The writing head comprises thin film elements including marking elements, high and low voltage bus lines, driver circuitry, and switching elements, integrally fabricated upon a large area substrate. A latching circuit, including at least one of the switching elements is located between the pair of bus lines for connecting the marking elements directly to one of the bus lines, so as to insure that the marking elements are always connected to a source of reference potential.

Abstract: A fluid jet assisted ion projection copier including a marking head incorporating an array of thin film ion modulating electrodes and photosensors integrated upon a single substrate. An optical projection system places incremental images of light and dark areas from an original to be copied onto the photosensor array. The marking head is mounted upon the ion projection housing, adjacent an outlet channel thereof for controlling the passage of ions out of the housing in accordance with the projected pattern of light and dark areas.

Abstract: An electrographic writing head capable of placing continuous marks upon a record medium in response to the application of a high voltage to selected writing styluses. The writing head includes a substrate upon which stylus electrodes, multiplexed driver circuitry and active devices are integrally fabricated by thin film deposition techniques. For each stylus, there is provided a high voltage thin film transistor and a latching circuit for holding the state of the high voltage transistor for substantially an entire line writing time.

Abstract: A fluid jet assisted ion projection electrographic marking apparatus including a marking head having integrally fabricated thereon, an array of modulating electrodes, divided into sections, address bus lines, data bus lines and suitable thin film switches, for sequentially bringing the electrodes of a selected section to a predetermined voltage during a portion of the line scan time. The electrodes of non-selected sections in conjunction with the thin film switches, hold the predetermined voltage for controlling the passage of ions, exiting the apparatus, during the remainder of the line scan time.