Abstract: A printed circuit board includes a plurality of layers including attachment layers and routing layers; and via patterns formed in the plurality of layers, each of the via patterns including first and second signal vias forming a differential signal pair, the first and second signal vias extending through at least the attachment layers; ground vias extending through at least the attachment layers, the ground vias including ground conductors; and shadow vias located adjacent to each of the first and second signal vias, wherein the shadow vias are free of conductive material in the attachment layers. The printed circuit board may further include slot vias extending through the attachment layers and located between via patterns.

Abstract: A yarn for reinforcing composite material includes carbon nanotubes. The yarn has also been treated to promote interaction with a resinous matrix.

Abstract: A yarn for reinforcing composite material includes carbon nanotubes. The yarn has also been treated to promote interaction with a resinous matrix.

Abstract: A heat collector (50) is formed by at least one extruding step for reducing machining steps, and is assembled to a separately formed mounting frame (40) which may be stamped and formed or molded. The heat collector has flanges (53) which bear against retaining tabs (45) formed on the mounting frame, and may be held by solder, glue, or mechanical means. The heat collector may receive a heat dissipator (18), or may be formed as a heat sink (56) such as a pin-fin type heat sink. The mounting frame can be fixed to a printed circuit board or the like having a component such as a central processing unit which contacts the collector in order to cool the unit.

Abstract: A heat collector (50) is formed by at least one extruding step for reducing machining steps, and is assembled to a separately formed mounting frame (40) which may be stamped and formed or molded. The heat collector has flanges (53) which bear against retaining tabs (45) formed on the mounting frame, and may be held by solder, glue, or mechanical means. The heat collector may receive a heat dissipator (18), or may be formed as a heat sink (56) such as a pin-fin type heat sink. The mounting frame can be fixed to a printed circuit board or the like having a component such as a central processing unit which contacts the collector in order to cool the unit.

Abstract: In the embodiments of the simplified ink jet head described in the specification, a carbon body is formed with ink passages, such as internal passages extending through a carbon plate, pressure chambers on one side of a carbon plate, flow-through passages on the other side of the same plate and ink supply passages, and a piezoelectric plate is affixed to the pressure chamber side of the carbon plate by a thin layer of epoxy adhesive. The piezoelectric plate may have a conductive coating on one side which is photo-etched to produce an electrode pattern corresponding to the pattern of the pressure chambers in the carbon plate. An orifice plate may have specially profiled orifice openings to assure axial projection of drops and may be affixed by a thin layer of epoxy adhesive to a carbon plate having orifice passages supplying ink from the pressure chambers to the orifices.

Abstract: Conditioning an ink jet orifice by illuminating the orifice with radiation to remove contaminants, smooth rough surfaces, and/or round sharp edges.

Abstract: A heat sink structure having a pipe attached to a plurality of fins for dissipating heat into an environment. Each fin in the plurality is constructed of a thermally conductive material and has a cavity formed therein dimensioned for seating about the pipe exterior surface. An opening or notch extends from the edge of each of the fins to the cavity to facilitate the spread of an adhesive or solder to the fin/pipe interface for providing thermal and physical coupling of the plurality of fins to the pipe.

Abstract: Conditioning an ink jet orifice by illuminating the orifice with radiation from a laser to remove contaminants and smooth rough surfaces.

Abstract: In the embodiments described in the specification, a piezoelectric transducer has electrodes to the piezoelectric layer with an adhesive bonding agent under pressure applied hydraulically so as to be distributed uniformly throughout the surface of the piezoelectric layer. In one embodiment the dielectric film also carries conductor arrays for connecting the electrodes to remote driver chips at locations spaced from the surface of the piezoelectric layer.

Abstract: A heat sink has a surface with a plurality of slots having mutually facing sidewalls which converge toward the base of the slot at an angle. Each slot receives an end portion of a cooling fin having sidewalls which converge at the same angle, so that the sidewalls of the slot are at least substantially parallel to the sidewalls of the cooling fin. The slots are preferably machined in the base and the sidewalls on the fins are machined or coined, yielding tolerances which are so close that the gap between parts is less than 60 microinches, and unfilled adhesive can be used. The thinness of the bond provides good thermal conductivity and reduced curing time. It is also possible to, provide the slots with a slightly smaller angle so that the base deforms to accommodate the cooling fin and adhesive may be eliminated.

Abstract: In the embodiments of the simplified ink jet head described in the specification, a carbon body is formed with ink passages, such as internal passages extending through a carbon plate, pressure chambers on one side of a carbon plate, flowthrough passages on the other side of the same plate and ink supply passages, and a piezoelectric plate is affixed to the pressure chamber side of the carbon plate by a thin layer of epoxy adhesive. In one alternative embodiment, an ink jet head assembly contains two separate carbon pressure chamber plates, a carbon manifold plate and a carbon collar to retain the carbon plates in an assembly.

Abstract: In the embodiments of the simplified ink jet head described in the specification, a carbon body is formed with ink passages, such as internal passages extending through a carbon plate, pressure chambers on one side of a carbon plate, flowthrough passages on the other side of the same plate and ink supply passages, and a piezoelectric plate is affixed to the pressure chamber side of the carbon plate by a thin layer of epoxy adhesive. The piezoelectric plate may have a conductive coating on one side which is photoetched to produce an electrode pattern corresponding to the pattern of the pressure chambers in the carbon plate. An orifice plate may have specially profiled orifice openings to assure axial projection of drops and may be affixed by a thin layer of epoxy adhesive to a carbon plate having orifice passages supplying ink from the pressure chambers to the orifices.

Abstract: A heat sink has a surface with a plurality of slots having mutually facing sidewalls which converge toward the base of the slot at an angle. Each slot receives an end portion of a cooling fin having sidewalls which converge at the same angle, so that the sidewalls of the slot are at least substantially parallel to the sidewalls of the cooling fin. The slots are preferably machined in the base and the sidewalls on the fins are machined or coined, yielding tolerances which are so close that the gap between parts is less than 60 microinches, and unfilled adhesive can be used. The thinness of the bond provides good thermal conductivity and reduced curing time. It is also possible to provide the slots with a slightly smaller angle so that the base deforms to accommodate the cooling fin and adhesive may be eliminated.

Abstract: A heat sink structure having a pipe attached to a plurality of fins for dissipating heat into an environment. Each fin in the plurality is constructed of a thermally conductive material and has a cavity formed therein dimensioned for seating about the pipe exterior surface. An opening or notch extends from the edge of each of the fins to the cavity to facilitate the spread of an adhesive or solder to the fin/pipe interface for providing thermal and physical coupling of the plurality of fins to the pipe.

Abstract: In the embodiments described in the specification, electrodes are bonded to the surface of a ceramic piezoelectric layer by supporting electrodes having a reduced dimension on a flexible dielectric film and placing the dielectric film under tension to expand the film and the electrodes sufficiently to conform the electrodes to the desired electrode pattern on the ceramic piezoelectric layer. The electrodes are then bonded to the piezoelectric layer with an adhesive bonding agent under pressure applied hydraulically so as to be distributed uniformly throughout the surface of the piezoelectric layer. In one embodiment the dielectric film also carries conductor arrays for connecting the electrodes to remote driver chips at locations spaced from the surface of the piezoelectric layer.

Abstract: In the ink jet printing system described in the specification, a hot melt ink jet printhead having two ink reservoirs is coupled through an ink supply line to a remote hot melt ink supply and a temperature controller is arranged to control the temperatures of the ink in the remote ink supply, the supply line, the ink reservoirs in the printhead and passages leading from the reservoirs to the ink jet orifices at selected temperature levels to inhibit high-temperature degradation of the ink while permitting the ink to be jetted at the desired jetting temperature. In addition, a pressure control system controls the pressure of the ink in the printhead at one or more selected levels to permit the printhead to be used at different orientations and to permit purging of air bubbles and contaminants from the orifice passageways and to supply a relatively high vacuum to a deaerator in the printhead to extract dissolved air from the ink.

Abstract: In the embodiments described in the specification, electrodes are bonded to the surface of a ceramic piezoelectric layer by supporting electrodes having a reduced dimension on a flexible dielectric film and placing the dielectric film under tension to expand the film and the electrodes sufficiently to conform the electrodes to the desired electrode pattern on the ceramic piezoelectric layer. The electrodes are then bonded to the piezoelectric layer with an adhesive bonding agent under pressure applied hydraulically so as to be distributed uniformly throughout the surface of the piezoelectric layer. In one embodiment the dielectric film also carries conductor arrays for connecting the electrodes to remote driver chips at locations spaced from the surface of the piezoelectric layer.

Abstract: In the simplified ink jet head described in the specification, a tubular member made of air-permeable, ink-permeable material which is closed at one end and connected at the other end to a source of subatmospheric pressure is inserted into an ink passage in the ink jet head to extract dissolved air through the material of the tubular member from a surrounding body of ink in the ink passage.

Abstract: In the particular embodiments described in the specification, a thin-film PZT piezoelectric transducer ink jet head includes a dielectric layer with electrodes and a thin film piezoelectric layer having a thickness in the range of 1-25 microns including one or more layers of perovskite-seeded PZT material and a further pattern of electrodes on the surface of the PZT layer along with a silicon substrate containing openings to provide ink chambers in the region of the electrodes. An orifice plate affixed to the substrate encloses the ink.