Abstract: An electrode structure (100) for an addressing structure using an ionizable gaseous medium has a substrate (102) and a cover (126). A plurality of channel-defining portions (116, 118, 120, 122, 124) each extend from the substrate to the cover; each pair of adjacent channel-defining portions defines a plasma discharge channel (129, 131, 133, 135, 137) for the ionizable gaseous medium. An electrode (104, 106, 108, 110, 112) extends through each channel-defining portion so that the electrode has a surface exposed to each of the channels defined in part by the channel-defining portion. Each of the channel defining portions or walls separates each electrode from the cover. An addressing structure using the electrode structure of the invention ionizes the gas in each channel by driving the electrodes of the pair of adjacent channel-defining portions that define the channel.

Abstract: A plasma addressed liquid crystal display (10) uses a liquid crystal material (18) having a low .DELTA..epsilon., .epsilon..sub..perp., and .DELTA.n, resulting in reduced sensitivity to cross talk, reduced operating voltage, and improved resistance to the deleterious electrochemical effects of direct current biases. Liquid crystal layers of low .DELTA..epsilon., .epsilon..sub..perp., and .DELTA.n materials exhibit lower capacitance, which increases the threshold voltage and reduces the saturation voltage to achieve reduced sensitivity to crosstalk and a lower operating voltage.

Abstract: A gray scale LCD cell device (116) combines a liquid crystal cell (80) having a symmetrical director field (82, 82') with a negative birefringence compensator plate (110) and interposes them between a pair of linear polarizers (112, 114). The symmetrical director field produces a symmetrical but nonuniform gray scale or color viewing circle curve (100) from the liquid crystal cell. The negative birefringence plate restores the gray scale or color viewing angle uniformity. When graphed on a polar plot, the measured light transmission percentage curves (120, 122, 124) characterizing the LCD are substantially concentric circles surrounding the optical axis (18) for all azimuthal angles (28) and viewing angles (24) up to 30 degrees. Adding colored filters (152) to a color cell triad (150) provides a basis for a multi-color display having uniformly perceived colors over a wide range of azimuthal and viewing angles.

Abstract: A stereoscopic imaging system (10) includes a display (14) and stereoscopic glasses (18) having right-and left-eye pieces (20 and 22). A photodetector (28) in the glasses receives electromagnetic radiation including IR pulses, having fast rise times, from a transmitter (26), and noise from ambient light and other electromagnetic radiation. An ambient light filter (34) filters out low frequency and low amplitude noise created by ambient light and other electromagnetic signals. The ambient light filter employs a high pass filter cancellation loop (42) that cancels low frequency components, a high frequency amplifier (50) that provides unity gain to low frequency components, and a high pass filter (C3 and R9). The ambient light filter also employs a threshold adjusting circuit (64) that temporarily adjusts the threshold voltage of a comparator (60) in response to reception of the IR pulses.

Abstract: A thermal transfer printer (10) includes multiple media trays (16, 120, 126) each encoded to communicate to a printer controller (46) via sensors (132, 134, 136) a print medium size and type contained in the tray, and a pair of thermal transfer ribbon (24) sensors (44,45) to communicate whether the ribbon includes a pre-coat material panel (34). A printer driver responsive to the media size and type sensors and the thermal transfer ribbon sensors to causes pre-coat material to be applied to coated or plain paper print media but not to transparency print media. Post-rendering color correction is provided for color images printed on various media type and pre-coat combinations. The printer driver prevents an image from printing when potentially wasteful conditions are detected in response to a print job request, forced tray selection, or automatic tray switching selection.

Abstract: An ink jet printer (10) having a print head (14) for directing an ink jet toward a sheet of paper (16) includes automatic print head spacing apparatus (80) that holds the print head apart from the sheet of paper by a preselected distance. In a preferred embodiment, the printer includes a rotatable drum (20) for supporting the sheet of paper and media securing system (24) of a first predetermined thickness for securing the paper to the drum. The print head is positioned at the preselected distance after a major surface (130) of the print head engages and is pushed back by the media securing system.

Abstract: A signal acquisition and sampling system mounted in an oscilloscope probe includes an input buffer amplifier (30) featuring shunt feedback, offset capability, input bias current compensation, and very low input capacitance. Signal sampling is accomplished by a cascaded pair of differential sampling bridges including a fast track-and-hold stage (40) followed by a slow track-and-hold stage (50). The differential configuration of the bridges features common mode rejection of strobe signal coupling into the signal path and reduces aberrations and voltage droop. The fast track-and-hold stage features Schottky diode switching bridges (42A) and (42B), low value storage capacitors (44A) and (44B), thereby resulting in a fast tracking time. The slow track-and-hold stage features low-leakage diode-connected transistor switching bridges (52A) and (52B) and a FET buffer stage, thereby resulting in fast acquisition of the fast stage output and long hold time for quantization of the sample.

Abstract: A multi-orifice ink jet print head array (32) includes multiple drive circuits that drive respective PZTs (16) to cause ink drops to be ejected from respective orifices (28). Each drive circuit includes a voltage divider (36) having a resistor R.sub.S. The ink drop ejection velocity is controlled by selecting an appropriate value of R.sub.S for each voltage divider, thereby compensating for imperfections in manufacturing of the print head array. The value of a particular R.sub.S is selected by temporarily connecting the corresponding voltage divider (36A), in which the value of R.sub.S is R.sub.I, to assessment circuit (56). The assessment circuit includes a potentiometer (66) with resistance value R.sub.POT. Ink drops are ejected at a rapid periodic rate as a camera (102) records the position of the ink drops with respect to a graticule (94) at the time a strobe (100) flashes. The value of R.sub.POT is adjusted until the ink drops are on the graticule as viewed on a monitor (108), at which time R.sub.POT =R.

Abstract: The present invention (50) corrects duty-cycle errors generated by imperfections in encoder scales and encoder detectors. A preferred embodiment of the invention operates by detecting successive transparent-to-opaque transitions of the encoder scale (20), calculating the distance between the transitions, dividing that distance by two, and generating a synthetic encoder pluse that is timed to represent a position 50 percent of the distance between the transparent-to-opaque transitions.