Abstract: An oblique incidence multispectral interferometric apparatus and the process of using it for measuring gross surface height errors of for measuring the total thickness of a substrate such as a semiconductor wafer or a photo mask. The instrumentation can be configured to either measure the air film between a reference flat and the substrate, or it can measure the air film on both sides of a substrate placed between reference flats. If the substrate is a flexible silicon wafer then it can be held against a known reference flat using a vacuum or other suitable means or the wafer surface can be measured from both sides in a free standing mode. In all cases the thickness map of the air space or spaces between the substrate surface or surfaces and a corresponding calibrated reference surface is measured using multispectral pattern matching.

Abstract: A transceiver is described which utilizes D-shaped optical fiber technology and advanced flip chip mounting techniques for manufacturing an integrated transceiver chip for use in electronic microcircuit applications. A single D-shaped optical fiber is used for bi-directional signal transmission, with coupling gratings superimposed on the flat surface of the fiber for coupling light into and out of the optical fiber. A light source and optical detector, aligned with the respective coupling grating for optical communication with the fiber, are flip mounted on the substrate which supports the fiber. Finally, the light source and optical detector are electrically connected with associated electronic circuitry also mounted or fabricated on the substrate.

Abstract: A magnetoresistor is monolithically integrated with an active circuit by growing a thin film magnetoresistor on a semiconductor substrate after the substrate has been doped and annealed for the active devices. The magnetoresistor is grown through a window in a mask, with the mask and magnetoresistor materials selected such that the magnetoresistor is substantially non-adherent to the mask. InSb is preferred for the magnetoresistor, Si.sub.3 N.sub.4 for the mask and GaAs for the substrate. The non-adherence allows the mask to be substantially thinner than the magnetoresistor without impairing the removal of the mask after the magnetoresistor has been established.

Abstract: A process is provided for passivating surfaces (12') of III-V microwave monolithic integrated circuit (MMIC) flip chips (40). Essentially, two cured, patterned polyimide layers (10, 28) are applied, one on the chip surface supporting a gold-plated bridge (26) and passivating the surface and the other over the gold-plated bridge to passivate the bridge surface. Further, a silver-titanium composite layer (32) is deposited over a gold-plated bump-post (24), which is then covered by a silver-plated bump (38), in order to prevent scavenging of gold from the bump-post by a subsequent Pb-Sn reflow solder process used to mount the chip to a metallized ceramic substrate. The process of the invention facilitates a more compatible reflow solder silk-screening process with passivated III-V MMIC flip chips, resulting in a more uniform and consistent solder thickness and relieving a tight tolerance requirement on the plated silver bump height uniformity.

Abstract: A membrane test probe (10) for use in testing integrated circuit chips (50) has a thin flexible membrane (30) bearing test contacts (40,42) that is stretched across an opening of a rigid-flex substrate (12). The membrane is manufactured with uniform radial tension by a lamination fixture having a steel pressure plate (76) that includes an annular groove (78). A high temperature O-ring (80) is positioned in the groove against the radially inner wall (82) of the groove with the radially outer wall of the groove being displaced from the outer part of the O-ring. The O-ring has a thickness greater than the depth of the groove and when the steel pressure plate is pressed against the membrane to press it against its substrate the O-ring pushes a portion (92) of the membrane into a shallow groove (16) in the substrate and deforms radially outwardly. As the O-ring deforms radially outwardly, it exerts a radially outwardly directed tension on the membrane which is cured in this radially stretched condition.

Abstract: A system, a portable propellant loading tank and loading method for bipropellant spacecraft servicing to load propellant into a spacecraft. The spacecraft has a propellant storage tank with a propellant input and a vent output. The system comprises a portable propellant loading tank for storing and transferring propellant that is couplable to the propellant input of the propellant storage tank in the spacecraft. The propellant loading tank is a stainless steel tank that is electropolished on its interior surface. A portable weighing system having a plurality of load cells provides output signals indicative of the weight of the propellant loading tank. A load cell readout device is coupled to the portable weighing system for providing an output indicative of the weight of the propellant storage tank. A receiver tank is coupled to the vent output of the propellant storage tank in the spacecraft.

Abstract: An optical display system in which an image is projected onto a combiner surface at a significant bending angle effectively compensates asymmetric aberrations, including quadratic, linear and constant binodal astigmatism components and both linear and constant coma components. Forward and rear optical lens relay groups are positioned between an image generator and the combiner surface. The two relay groups are independently decentered and angularly tilted to increase the degrees of freedom available for aberration compensation. The lenses included in the two relay groups are also designed to compensate for chromatic aberrations, thus allowing for the use of a broad bandwidth combiner and an operating bandwidth that encompasses substantially the full visible spectrum. The reduction in aberrations makes possible a significant increase in the system's field of view.

Abstract: A DC-to-AC power converter for use with a three phase motor that allows the motor to continue to operate at reduced power in the event of a switch failure in the converter. This is accomplished by using parallel power semiconductor switch poles for each phase. The motor may be wound with parallel windings for each phase to aid current sharing of the parallel poles. This feature is not absolutely required, but the impedance of the windings help balance the currents in the parallel poles. The arrangement of parallel switch poles allows for continued operation of the motor at half of its rated power level in the event of a failure of one of the power switches. Switching frequency and duty cycle of the parallel poles are controlled by a single pulse width modulation signal which is connected to the two drive circuits that control the switches. Fuses, or other circuit disconnect devices are added between the power switch pole outputs and their respective windings of the motor to isolate a failed power switch.

Abstract: A fine grained multi-planar clutter rejection processor (10) for correlating multiple sets of data. The processor (10) maps each set of data onto a plurality of arrays (28-34). The data includes target data which is correlated between sets and clutter which is uncorrelated between sets of data. The system also includes a means for shifting (40) the positions of the second and subsequent arrays in a pattern which is larger for each successive array. In addition, a correlation identification unit (78) identifies the coordinate locations in the first array (28) which contain data points and which also contain data points in subsequent arrays in their shifted positions. In this way, data points identified in this manner are correlated and the remaining data points can be discarded as clutter. The processor (10) system is able to handle a very large number of data points per scan (over 100,000) over a high number of scans (such as eight).

Abstract: A hologram copying system that includes a first reconstruction beam, a second reconstruction beam that is incoherent with respect to the first reconstruction beam, a first master hologram responsive to the first reconstruction beam for producing a first diffracted beam, a second master hologram responsive to the second reconstruction beam for producing a second diffracted beam, and a holographic recording layer responsive to the first and second reconstruction beams and the first and second diffracted beams, whereby a first hologram is formed by interference of the first reconstruction beam and the first diffracted beam, and a second hologram is formed by interference of the second reconstruction beam and the second diffracted beam.

Abstract: A method for transferring a photopolymer hologram from a curved exposure surface to a curved application surface including the steps of forming a release layer on the exposure surface, forming a photopolymer layer on the release layer, forming a protective layer on the photopolymer layer, recording a hologram in the photopolymer layer, removing the protective layer, attaching the laminar assembly comprised of the exposure substrate, the release layer and the photopolymer layer to the curved application surface of the final substrate with an optical adhesive layer located between the photopolymer layer and the curved application surface, and removing the exposure substrate from the release layer.

Abstract: An encoded hologram that produces a first image and a second image pursuant to playback illumination, wherein the first image is resolvable by human vision while the second image is not resolvable by human vision when the playback illumination comprises non-coherent broad band illumination, and wherein the second image is machine readable when the hologram is illuminated with playback illumination that is based on the original reference beam.

Abstract: A plasma ion implantation apparatus includes a vacuum chamber that receives the object within its walls. The object is supported upon an electrically conductive base that is electrically isolated from the wall of the vacuum chamber. An electrically conductive enclosure is positioned between the object and the wall of the vacuum chamber and supported upon the base. The enclosure is made of an electrically conductive material. A plasma source is positioned so as to create a plasma in the vicinity of the object to be implanted. A voltage source applies an electrical voltage to the base and thence the enclosure relative to the wall of the vacuum chamber. Secondary electrons emitted from the object during implantation are reflected back into the plasma by the enclosure, reducing X-ray production and improving plasma efficiency.

Abstract: A unitized multilayer circuit structure that includes a plurality of planar dielectric insulating layers stacked in laminar fashion to form a substrate having sides formed by edges of the dielectric insulating layers and recessed regions formed in one or more one sides of the substrate for use in attaching the unitized multilayer circuit structure to a higher level assembly or for attaching electrical contact circuitry to the unitized multilayer circuit structure.

Abstract: A degaussing system for color monitors is disclosed. During a degaussing cycle, the system successively reverses the coupling in a bridge circuit between a degaussing coil and a storage capacitor so as to generate oppositely directed degaussing currents through the coil. To insure that the residual magnetism after degaussing is substantially zero, feedback signals are developed in a feedback circuit and applied through a control circuit to the bridge circuit to successively decrease the coil's current magnitudes until they reach a predetermined threshold. Simultaneously, the feedback signals are adjusted to cause the time-integrated current in one direction of the coil to substantially equal the time-integrated current in the other coil direction.

Abstract: The inductive charge coupler carrying the transformer primary is supplied with coolant fluid. The inductive charge receptacle mounted on the automobile has interior cooling fluid passages and there is a duct to transfer the cooling fluid from the inductive charge coupler to the cooling fluid passages in the inductive charge receptacle.

Abstract: A dielectric material having a dielectric constant which varies inversely with frequency, and preferably with the second power of frequency, fills the space between a radiator and a reflecting groundplane. The back-directed wave is reflected back to the radiator in phase with the directly radiated wave over a wide frequency band, increasing the radiator efficiency.

Abstract: A hologram structure for use in a holographic center high mounted stoplight system for a vehicle. The hologram structure includes an illumination source for providing a reconstruction beam, a first array of non-overlapping hologram cells and non-hologram cells, and a second array of non-overlapping hologram and non-hologram cells. Each hologram cell of the first array produces a specular image that is viewable in a first predetermined angular field pursuant to diffraction of a portion of the reconstruction beam, and each hologram cell of the second array produces a diffuse image that is viewable in a second predetermined angular field pursuant to diffraction of a portion of the reconstruction beam. The specular images and diffuse images produced by the first and second holograms form stoplight illumination.

Abstract: A surface condition sensing system includes a frequency controlled source of electromagnetic power adapted to produce a band of selected frequencies which are directed to a surface under examination. A monitoring circuit compares transmitted and reflected electromagnetic power as a function of frequency from the surface, and generates a plurality of absorption signals representing the difference between the amplitude of the transmitted signal with the corresponding amplitude of the reflected signal. An evaluator circuit generates a surface condition signal representing the results of a comparison between the plurality of absorption signals with known surface models. A control circuit generates a status signal representative of the surface condition. The system can be configured as a road condition sensor or as an aircraft ice detection sensor.

Abstract: Code excited linear prediction (CELP) is performed using two voiced and unvoiced sets of windows, each set is used both for linear prediction and pitch determination. The accompanying degradation in voice quality is comparable to the IS54 standard 8.0 Kbps voice coder employed in U.S. digital cellular systems. This is accomplished by using the same parametric model used in traditional CELP coders but determining, quantizing, encoding, and updating these parameters differently. The low bit rate speech decoder is like most CELP decoders except that it operates in two modes depending on the received mode bit. Both pitch prefiltering and global postfiltering are employed for enhancement of the synthesized speech. In addition, built-in error detection and error recovery schemes are used that help mitigate the effects of any uncorrectable transmission errors.