Abstract: The present invention provides an ink jet print head capable of fast, efficient and consistent printing. Such ink jet print heads include an ink ejecting component which incorporates electropolished surfaces. Electropolishing techniques useful in the production of such ink ejecting components are also discussed.

Abstract: A plasma addressing structure (52) having an ionizable gas captured within each of multiple parallel channels (62a) extending across a display screen (54) includes an arrangement (132a) of anodes (112a) and cathodes (114a) for selectively ionizing the gas to address data elements. The anode in each channel has an extended width (130a) in a direction transverse to the length of the channel, thereby to provide the channel with a relatively large conductive surface area that facilitates the ionization of the gas contained in the channel. The large conductive surface provided by the extended width of the anode allows each channel to be formed with a shallow depth (118a) that enhances the viewing angle characteristics of the display screen and simplifies the manufacture of the addressing structure.

Abstract: An interface system allows a user to select and control colors used in graphic images generated by a computer system. The interface system employs graphical representations of the hue, chroma, and lightness combinations capable of being rendered by a computer graphics system. In a preferred embodiment, the graphical representation includes a one-dimensional graph (40) depicting the range of hues and a two-dimensional graph (42) depicting the range of chroma and value combinations available for a selected hue. The graphical representations are preferably rendered in accordance with a Hue-Value-Chroma ("HVC") color space (90) having a high degree of perceptual uniformity.

Abstract: A plasma addressing structure functioning as a display panel (52) includes an ionizable gas captured within a network (110) of intersecting channels formed by multiple spaced-apart islands (60) arranged in substantially parallel rows (62) projecting from the major surface (104) of an underlying substrate (64). The network of channels includes elongated channels (112) that are positioned between adjacent rows of islands, and spur channels (114) that extend between individual islands in each row and couple adjacent elongated channels. The gas in the network of channels is selectively ionized to address display elements (54), which are aligned with the islands positioned along each of the island rows. Each island has a top surface or plateau (128) that is spaced-apart from and substantially parallel to the major surface from which the island projects.

Abstract: The present invention includes a cathode-ray tube (10) capable of providing a high-brightness, high-resolution large screen display that is compatible with, for example, field sequential liquid crystal color display systems and monochrome imaging systems. Preferably, the tube includes a small-diameter cathode assembly (14 of 110) with an adjacent small-diameter control grid electrode (38 or 114). The small diameters of the cathode assembly and the control grid electrode result in relatively little capacitance and are, therefore, compatible with relatively high video signal bandwidths. A thick accelerating electrode (66 or 150) is positioned adjacent the control grid electrode to prefocus the electron beam and, thereby, form it with relatively low spherical aberration. In a preferred embodiment, the electron beam is modulated in a push-pull manner by applying a video modulation signal and its inverse to the cathode and the control grid electrode.

Abstract: An ink jet print head cleaning and maintenance system has a purge chamber for applying a vacuum to a nozzle orifice surface. A specialized baffle diverts ink entering the purge chamber away a vent port through which the vacuum is drawn. An elongated wipe engages and wipes the orifice surface and is preferably moved at an extremely slow rate across the surface to enhance the wiping operation. An air knife directs a narrow stream of air across a portion of the nozzle orifice surface with air from the air stream being scanned across the surface for cleaning purposes. A specialized drip edge is positioned beneath the orifice surface for directing drops of ink away from the ink jet print head, the drops of ink being generated during the cleaning procedures. A mechanically simple cam mechanism coupled to a rotatable drum of the printer may be used to shift the maintenance system against the nozzle orifice surface for cleaning purposes.

Abstract: A projection lens assembly (10) projects onto a display screen (38) electrons emitted from an output side (86) of an electron multiplier such as, for example, a microchannel plate (70). The projection lens assembly includes a dome-shaped mesh element (16) that is concave as viewed from the display screen. The mesh element is positioned between the microchannel plate and a filter element (20) having a beam-limiting aperture (22). The mesh element is of an aspherical shape that allows the projection lens assembly to project the electrons toward the display screen with substantially no spherical aberration, thereby forming near the beam-limiting aperture an electron beam crossover of small diameter. The beam-limiting aperture is formed with a relatively small diameter that allows the filter element to block electrons of energies outside a preselected range of energy values, thereby reducing chromatic aberration in the image formed on the display screen.

Abstract: A cathode-ray tube (10) includes a prefocusing lens (14) and an adjacent high-voltage einzel focus lens (16) to form an electron beam with low spherical aberration. The high-voltage einzel focus lens includes a central lens element (52) positioned between a pair of outer lens elements (54) and (56). The outer lens elements receive a common high-voltage potential of more than about 12 kilovolts. The prefocusing lens includes a G3 electrode positioned between an anode (48) and a first one of the outer lens elements of the einzel focus lens. The G3 electrode receives the high voltage applied to the outer lens elements. In a preferred embodiment, the G3 electrode is a flat end disc plate (57b) on the end of the first one of the outer lens elements.

Abstract: A touch panel has panel scanning signals selectively applied to the four sides of a touch sensing surface of the panel so as to establish alternating current voltage gradients in desired directions across the touch sensing surface. When the panel is touched, touch signals result and are utilized by a touch location circuit in determining the location of touch. The impedance touch current resulting from a user's touch may also be determined and used. The touch panel circuit automatically filters the touch signals to an extent which varies depending upon the rate of movement of touch from one location on the touch sensing surface to a subsequent location. Filtering is decreased with the increasing rates of movement. The touch panel thereby minimizes the effects of noise on touch location determination.

Abstract: A flat panel apparatus for and a method of addressing data storage locations (80) employs a row-scanning electron beam (76) to address simultaneously a row (120) of such storage locations and thereby store data in and read data out of them. The storage locations are defined by the overlapping areas of multiple column electrodes (62) extending in a common direction on a first substrate (82) and rows addressed by the electron beam and extending in a common direction on a second substrate (54). A layer of dielectric material (52) separate the first and the second substrates, which are positioned face-to-face and spaced-apart with the direction of the addressed rows transverse to that of the column electrodes. The column electrodes receive data drive signals.

Abstract: A cathode-ray tube (54) includes a bipotential electrode structure (50) that converges the electrons in an electron beam. The bipotential electrode structure includes a cylindrical metallic electrode (56) positioned within a neck portion (66) of an evacuated glass envelope (52) and an electrically resistive coating (58) on an interior surface (60) of the neck portion. The resistive coating has a terminal end (64) positioned adjacent the metallic electrode. An electrically and thermally conductive coating (62) on the interior surface of the neck portion covers the terminal end of the resistive coating and partly overlaps the metallic electrode. The conductive coating functions to prevent electric "punch-through" between the interior and exterior surfaces of the tubular envelope. The conductive coating also allows relatively efficient operation of a beam deflection apparatus.

Abstract: A capacitive touch panel system (10) having a faceplate (14) with an electrically conductive layer (20) of a consistent resistivity employs a position measurement apparatus (12) to generate an address signal indicative of a position (46) on the faceplate in contact with a stylus (48). The position measurement apparatus includes a position measurement signal source (56) that generates a square-wave measurement signal of a frequency that varies in a substantially random manner. The position measurement signal is applied to a first pair of opposed electrodes (36) and (40) and a second pair of opposed electrodes (38) and (42) positioned along respective side margins (26, 30, 28, and 32) of the faceplate. The resistivity of the conductive layer establishes effective resistances of R.sub.x and R.sub.y between the respective first and second pairs of electrodes.

Abstract: A liquid crystal light valve (10) includes compensation for wire shadow effects caused by the interception of writing beam primary electrons as they propagate through the collector electrode (66). The wire shadows stem from the lack of charge deposited on target surface regions ( 106) intended to be addressed by the writing electron beam (60a). The present invention applies to the collector electrode an appropriate voltage that diverts the paths (112) of nonintercepted writing beam electrons toward target surface regions directly below the collector electrode portions that intercepted the writing beam electrons. Diverting the paths of nonintercepted electrons provides a more uniform charge distribution on the target surface (45) and thereby fills the charge voids created by the electron intercepting portions of the collector electrode.

Abstract: A stereoscopic graphics display terminal (10) having an image data processor (22) generates stereoscopic image data from three-dimensional image data. In a preferred embodiment, the graphics display terminal receives from a main or host computer (12) three-dimensional image data corresponding to a three-dimensional representation of an object. The three-dimensional image data are typically generated by an application program that resides in the host computer. The image data processor includes an image orienting system (74) that receives the three-dimensional image data and adaptes such data to represent a preselected orientation of the object and thereby provide an observer with a preselected view of the object. The adaptation of the three-dimensional image data by the image orienting system entails image manipulations that include rotating, translating, and scaling the size of the image.

Abstract: A method and an apparatus render on a display screen (14) an image of a three-dimensional object. The object is represented by image data arranged in a constructive solid geometry format including at least one halfspace that divides an object space (28) into an interior region that lies inside the halfspace and an exterior region that lies outside the halfspace. The boundary of the halfspace is defined by an implicit mathematical function. The method includes subdividing the object space into volume elements of either a cubical or rectangular parallelepiped shape. For each volume element, an upper bound and a lower bound are calculated to the values of each function defining the boundary of a halfspace. In a first preferred embodiment, the calculation of the upper and lower bounds of the function defining a halfspace within a volume element identifies all of the extrema of the function that lie in or on the boundary of the volume element.

Abstract: An electron beam addressed liquid crystal light modulator or "valve" (10) includes a liquid crystasl cell (40) having a target surface (45) which a writing electron beam (60a) and an erasing electron beam (60b) address to provide a display image. The writing electron beam and the erasing electron beam sequentially strike preselected locations on the target surface to cause an emission of secondary electrons and, thereby, develop an electrostatic potential at such preselected locations. A secondary electron collector electrode (66) positioned over and above the target surface collects in a uniform manner the secondary electrons emitted by all regions of the target surface. A collector electrode controller circuit (81) sequentially applied first and second potential differences between the target surface and the collector electrode in synchronism with the striking of the preselected locations by the respective writing and erasing beams.

Abstract: A stereoscopic graphics display system (10) has a stereoscopic window controller (18) that generates multiple windows (72 and 74) within which multiple images (76 and 78) are formed. The stereoscopic window controller directs the graphics display system to render around each window a border (80 and 82) representing an outline of the window. Each of the borders is rendered with zero binocular disparity to assist an observer to perceive the three-dimensional qualities of steroscopic images. Depth cue contradictions between stacked windows are reduced by rendering with zero binocular disparity the images in occluded windows.

Abstract: An apparatus for and a method of addressing data storage locations (80) employs an electron beam (76) to address such storage locations and thereby store data in and read data out of them. The storage locations are defined by the overlapping areas of multiple column electrodes (62) extending in a common direction on a first substrate (82) and rows (120) addressed by an electron beam (76) and extending in a common direction on a second substrate (54). A layer of dielectric material (52) separates the first and the second substrates, which are positioned face-to-face and spaced-apart with the direction of the addressed rows transverse to that of the column electrodes. The column electrodes receive data drive signals. The addressing apparatus is configured so that for each storage location secondary electrons emitted by the electron beam striking the location function as an electrical switch that changes between a conducting state and a nonconducting state in response to the presence of the electron beam.

Abstract: A multiple beam cathode-ray tube employs a bipotential electrode structure to provide acceleration and convergence of the electron beams without the use of a resistive helix coil. In a preferred embodiment, the bipotential electrode structure (10) is employed in a cathode-ray tube (14) in which a cathode (28) and a grid electrode structure (30) cooperate to form plural beams of high velocity electrons. The bipotential electrode structure includes an immersion lens cylinder (16) that is positioned upstream of a tubular electrode element (18). The outer diameter (226) of the immersion lens cylinder is less than the inner diameter (228) of the tubular electrode element, thereby allowing the downstream end of the immersion lens cylinder to extend into the upstream end of the tubular electrode element. A potential difference applied between the immersion lens cylinder and the tubular electrode element accelerates the electrons in the multiple beams and converges them to form an array of crossovers at a plane (64).

Abstract: A capacitive touch panel system (10) having a faceplate (14) with an electrically conductive layer (20) of a consistent resistivity employs a position measurement apparatus (12) to generate an address signal indicative of a position (46) on the faceplate in contact with a stylus (48). The position measurement apparatus includes a position measurement signal source (62) that generates a square-wave measurement signal of substantially constant frequency and a preselected magnitude. The position measurement signal is applied to a first pair of opposed electrodes (36) and (40) and a second pair of opposed electrodes (38) and (42) positioned along respective side margins (26, 30, 28, and 32) of the faceplate. The resistivity of the conductive layer establishes effective resistances of R.sub.x and R.sub.y between the respective first and second pairs of electrodes.