Abstract: A sequential electrochemical reduction method and apparatus for assessing solderability of electronic component leads and printed wiring boards. The method detects and quantifies the oxides present on copper, solder, and intermetallics that are detrimental to solderability. A solderable portion of the component to be tested is immersed in an electrolyte to form an electrode. An inert counter electrode and a reference electrode are also placed in the electrolyte. A current is passed from the inert counter electrode to the tested component, and the potential between the component and the reference electrode is recorded as a function of time. In a plot of the electrode potential versus the total charge passed, a series of inflection points identify and quantify particular metallic oxides present on the solder. The plot is compared with previous analyses of aged specimens having known oxide compositions that correlate with degradation of solderability.

Abstract: A III-V compound planar HBT-FET device integrates field effect transistors (FETs) with heterojunction bipolar transistors (HBTs) formed on the same semiconductor substrate. An HBT fabricated on the substrate includes a collector, a base, and an emitter. The HBT emitter comprises a lightly doped layer of a first conductivity type deposited atop a heavily doped base layer of a second conductivity type, a lightly doped emitter cap layer of the first conductivity type deposited atop the emitter layer, and a heavily doped emitter contact layer of the first conductivity type deposited atop the emitter cap layer. A FET, isolated from the HBT by areas of ion implantation, is formed in the layers of material deposited during fabrication of the HBT. The FET has a source and a drain formed in the heavily doped emitter contact layer, a gate recess etched in the emitter contact layer between the source and drain, and a Schottky gate metal contact deposited on the lightly doped emitter cap layer exposed in the gate recess.

Abstract: A system of active emitters and sensors is provided for measuring distance and communicating between vehicles on an automated highway. The preferred system utilizes a pair of spaced apart sensors at the front of each vehicle for stereo depth perception, two temporally modulated emitters on the rear of each vehicle for redundancy and inter-vehicle communication, and temporally modulated emitters positioned at intervals along the highway for communication from the highway to the vehicles. The emitters may transmit radiation at a wavelength, such as 1 .mu.m IR, for example, that can be detected by low cost detectors. The emitters are modulated temporally to transmit a binary code, resulting in signal-to-noise improvement and increased clutter rejection and operational range.

Abstract: A high temperature resist process is combined with microlithographic patterning for the production of materials, such as diamond films, that require a high temperature deposition environment. A conventional polymeric resist process may be used to deposit a pattern of high temperature resist material. With the high temperature resist in place and the polymeric resist removed, a high temperature deposition process may proceed without degradation of the resist pattern. After a desired film of material has been deposited, the high temperature resist is removed to leave the film in the pattern defined by the resist. For diamond films, a high temperature silicon nitride resist can be used for microlithographic patterning of a silicon substrate to provide a uniform distribution of diamond nucleation sites and to improve diamond film adhesion to the substrate.

Abstract: A self-timed bus arbitration and digital data transfer system is provided for a computer network having multiple master and slave devices sharing a digital data bus. Each master device includes a bus arbitration logic circuit having a time delay element. Each master contending for access to the data bus outputs an identifier on signal lines connecting the master devices. After a period of time comprising the slowest master's operational delay, the bus arbitration circuits determine, on a prioritized basis, which particular master shall have access to the data bus at that time. Upon gaining access, the particular master provides a request signal on a control line connecting the master and slave devices and provides an address on an address bus that may be multiplexed with the data bus. After each slave has decoded the address, as determined by the slowest slave's delay, an acknowledge signal is provided on the control line to the particular master so that data transfer may proceed to/from the selected slave.

Abstract: A method is provided for depositing a dense, high quality, superconducting coating on a substrate of large size and complex shape. The superconducting coating is deposited from a precursor melt that generally comprises the same constituents as the superconducting coating but not necessarily in the same proportions. The liquid precursor melt, which may bear suspended platelike crystals of the superconducting phase, flows into or through a smooth, fine-grained, porous substrate that is largely inert to the liquid precursor. The desired superconducting phase is the sole crystalline phase co-existing with the precursor melt over a range of conditions. The crystals have a pronounced platelike character and form on the substrate with their superconducting planes oriented parallel to the surfaces of the substrate.

Abstract: An electronic image processing system uses data provided by one or more sensors to perform cooperative computations and improve image recognition performance. A smoothing resistive network, which may comprise an integrated circuit chip, has switching elements connected to each node. The system uses a first sensory output comprising primitives, such as discontinuities or object boundaries, detected by at least a first sensor to define a region for smoothing of a second sensory output comprising at least a second, distinct output of the first sensor or a distinct output of at least a second sensor. A bit pattern for controlling the switches is generated from the detected image discontinuities in the first sensory output. The second sensory output is applied to the resistive network for data smoothing. The switches turned off by the data from the first sensory output define regional boundaries for smoothing of the data provided by the second sensory output.

Abstract: A long life fluorescent lighting system provides uniform white light illumination with high efficiency. The system includes a gas-filled lamp with no phosphors on the inside surface of the lamp. A diffuser plate or mirror external to the lamp includes a phosphor coating to convert ultraviolet radiation emitted by the lamp to uniform white light illumination. The lamp may be filled with mercury vapor enriched with .sup.196 Hg for emission of 254 nm wavelength ultraviolet radiation and minimization of radiation trapping. The system may include band pass reflectors for reflecting 254 nm radiation to the phosphors and reflecting unwanted 185 nm radiation away from the phosphors and back into the lamp. The system provides uniform, high efficiency white light output suitable for back illumination of liquid crystal displays.

Abstract: A method is provided for fabricating a fiber reinforced metal tube. A first, thin walled metal tube, such as a copper tube, is wrapped with layers of reinforcing fibers, such as copper coated graphite fibers. Layers of fibers aligned in the longitudinal direction of the tube, for example, may be alternated with layers of fibers aligned in the circumferential direction. The fiber wrapped tube is inserted into a second, thick walled metal tube having an inside diameter slightly larger than the outside diameter of the fiber wrapped tube. A vacuum may be formed in the fiber wrapped region between the two metal tubes. The fiber wrapped inner tube is then expanded radially against the inside of the thick walled tube with hot isostatic pressure to consolidate the reinforcing fibers into the metal, thereby forming the fiber reinforced metal tube.

Abstract: A method and apparatus are provided for photoelectrochemical reproduction of an image on a plate or roller. For a printing press, the apparatus includes a reusable image roller coated with a oxide semiconductor. A plating solution is applied to the image roller as a thin film. The desired image is written onto the oxide semiconductor by a laser that generates a photoelectrochemical reaction between the semiconductor and the plating solution. In a preferred embodiment, the image roller is coated with hydrophilic p-type NiO. The image is written onto the roller as dots of oleophilic metallic copper, which are formed on the NiO coating by laser-generated cathodic photoelectrodeposition. Subsequent erasure of the metallic copper image can be accomplished by chemical or electrochemical dissolution of the deposited copper. The method functions to create, erase, and recreate high-resolution images directly on a printing press roller without the necessity of precise matrix registration.

Abstract: A photorefractive device is provided for converting an image-bearing incoherent input beam to a high contrast coherent output beam the intensity of which varies as the square of the input intensity pattern. The device uses an incoherent image beam to write a holographic grating directly in a photorefractive medium. In one embodiment, a parallel, laterally displaced, telecentric system of lenses is used to split a quasi-monochromatic, incoherent image-bearing beam into two equal components. The two components are superimposed at the surface of the photorefractive medium to produce the hologram. In a second embodiment, the incoherent input beam is directed through a physically translating external grating to write the hologram in the photorefractive medium. The moving grating improves the diffraction efficiency of the hologram under the influence of an applied electric field and stabilizes the temporal response characteristics for signal processing.

Abstract: A gradient index codeposition process involving refractive index clipping is used to fabricate rugate filters having multiple reflectance bands. During the codeposition process, whenever the superimposed sine wave profiles extend beyond either the upper or lower refractive index limits of the optical materials involved, the index is held at its bound (i.e., clipped). A rugate filter having a multiplicity of stop bands can be fabricated using a rather limited range of refractive index excursions during the codeposition process. Loss of optical density from index clipping can be corrected by a compensating increase in filter thickness.

Abstract: A thin film, light absorbing coating comprises an analog structure fabricated by the simultaneous codeposition of absorbing and non-absorbing material. The two materials may comprise a non-absorbing dielectric material, such as silicon monoxide, and a metal, such as chromium, that is absorbing over the desired wavelength range. Individual evaporation rates for the two materials are adjusted during the codeposition process to achieve a continuously graded quintic transition between the absorbing material and the non-absorbing material. The continuous grading of the composition allows good light absorption properties to be maintained over a wide range of wavelengths. The total design thickness of the absorbing coating is on the order of a full wavelength of light. All wavelengths of incident light shorter than the design wavelength are absorbed into the coating. The coating is useful as a broad band light absorbing layer between a substrate and a spectrally selective reflective surface layer.

Abstract: A roughened surface of a conductive substrate, such as copper, provides uniform Sn-Pb solder coatings and improved solder retention at printed wiring board (PWB) plated through-hole rims (knees) and surface pads during solder dipping or reflow. A high density of copper surface features of moderate average roughness provides the most favorable solder coating thickness distribution. Various chemical or electrochemical etching processes may be used to produce the desired copper surface topography. Reflowed solder thickness distribution in a PWB knee region attained with a ferric chloride copper etching process peaks at 4 .mu.m, which provides a good margin of safety for preventing exposure/oxidation of the underlying Cu-Sn intermetallics. The ferric chloride copper etching process yields only 1% of solder thickness measurements in the undesirable 0-1.5 .mu.m range for plated through-hole rims. Copper surface roughening is expected to greatly reduce solderability loss in mass produced PWBs.

Abstract: An automatic tuner is provided for continuous, on-line tuning of proportional, integral, and derivative (PID) feedback controllers. The tuner compares the system input signals with the system response to generate estimates of system damping, frequency, and steady-state error, and then applies a set of if-then rules derived from mathematical and/or empirical analysis of the system parameters. The tuner represents each parameter of the rule-set by a "fuzzy" membership function, and an inference mechanism uses fuzzy logic for computing system outputs from the input values. The tuner also incorporates a self-monitoring mechanism to adjust the tuner output based on past performance. At each running cycle, the tuner computes a Euclidean distance between present values and desired values in the parameter-space represented by damping, frequency, and steady-state error. The output of the tuner is then scaled by a "reward factor" that is a function of the tuner effectiveness and consistency.

Abstract: A self-timed bus arbitration and digital data transfer system is provided for a computer network having multiple master and slave devices sharing a digital data bus. Each master device includes a bus arbitration logic circuit having a time delay element. Each master contending for access to the data bus outputs an identifier on signal lines connecting the master devices. After a period of time comprising the slowest master's operational delay, the bus arbitration circuits determine, on a prioritized basis, which particular master shall have access to the data bus at that time. Upon gaining access, the particular master provides a request signal on a control line connecting the master and slave devices and provides an address on an address bus that may be multiplexed with the data bus. After each slave has decoded the address, as determined by the slowest slave's delay, an acknowledge signal is provided on the control line to the particular master so that data transfer may proceed to/from the selected slave.

Abstract: Thermodynamically stable ceramic composites are provided for use in high temperature oxidizing environments. The composites comprise high strength alumina fibers (Al.sub.2 O.sub.3) in a ceramic matrix. The ceramic matrix comprises material similar to the fibers to improve compatibility of the composite materials. A material selected from the .beta.-alumina and magnetoplumbite family of materials is used to provide a weakly bonded interface between the fibers and the ceramic matrix. .beta.-aluminas and magnetoplumbites have weak layers as an intrinsic characteristic of their crystal structure, which comprise spinel layers (basically Al.sub.2 O.sub.3) separated by very weakly bonded planes containing the .beta.-forming ions. The weak planes of these materials allow preferential debonding and sliding, and thus inhibit crack growth across the interface between the fibers and the ceramic matrix. The alumina fibers can be coated with .beta.

Abstract: An optical system is provided for the transformation of input images to be correlated by a pattern recognition system. A pulse of light from a laser carries an input image to a beam splitter. The beam splitter divides the input pulse into an output pulse and a thoughput pulse that is directed through an optical ring resonator. The ring resonator is an optical reimaging system that transforms the input image in scale or orientation. The transformed version of the input image is then directed to the beam splitter where it is split into a modified output pulse and a modified throughput pulse that reenters the ring resonator. The transformation process is self-repeating to generate a series of successively modified output images that are equally spaced in time. The series of output images can be provided to an optical pattern recognition system for correlation with a stored reference.

Abstract: A method is provided for reconstructing an image transmitted through a thick distorting medium. A remote source provides coherent light at the object plane, and a local source, typically derived from the remote source, provides corresponding light that is coherent with respect to the remote source. Light from the remote source is directed through the thick aberrator and into a holographic medium, such as a photorefractive crystal, to interact with corresponding light from the local source and produce a volume hologram. An angularly multiplexed volume hologram, which covers the entire object field, is written into the holographic medium by successive exposures of light from the remote and local sources for successive pixels of the object plane. Light from an object, which comprises two-dimensional information from the object plane, can be reconstructed by the volume hologram after being distorted by the thick aberrator.

Abstract: A low-temperature, nondestructive method of electrochemical reduction is provided for restoring solderability of oxidized electronic component leads and solderable portions of printed wiring boards. The component or circuit board is immersed in an electrolyte solution. The electrolyte is chosen to be non-reactive with the circuit board and component materials. In one embodiment, the electrolyte comprises a benign borate buffer solution. The solderable portion of the component or circuit board is connected to the cathode of an electric power source to form a first electrode. A second, inert electrode is connected to the anode of the current source and immersed in the electrolyte. Current passing between the electrodes electrochemically reduces the metallic oxides on the solderable portions of the component or circuit board. In a second embodiment, the electrolyte comprises an active reducing agent.