Abstract: A method and apparatus for enabling the use of optical techniques for temperature measurement of a semiconducting substrate coated with an optically opaque overlayer. A reflective mirror structure is inserted between the semiconducting substrate and the optically opaque overlayer. The reflective structure prevents the overlayer from absorbing light transmitted through the semiconducting substrate and instead reflects the light, thereby restoring the substrate front-surface reflectivity required for temperature measurement analysis by optical techniques such as absorption edge reflectance spectroscopy.

Abstract: A scanning detection system. The inventive system includes a detector arrangement for scanning a target surface over a predetermined angular range and providing a plurality of sampled signals in response thereto. The detector outputs are sampled and aggregated to provide a first output having a constant spatial resolution independent of the scan angle of the detector. The detector outputs are also aggregated to provide a second output having fine radiometric sensitivity. In a specific implementation, constant resolution is achieved by co-adding a variable number of adjacent detector samples where the number of adjacent samples co-added is dependent on the scan angle. Fine radiometric sensitivity is achieved by co-adding a fixed number of adjacent samples. Thus, dual capabilities of constant resolution and high sensitivity are achieved in a cost effective manner.

Abstract: The angular and/or spectral bandwidth of a holographic lens assembly can be widened to accomodate highly diverging and/or wide spectral bandwidth illumination sources, respectively. Each lens in the lens assembly is comprised of a plurality of angularly customized holograms (an angularly customized hologram set). Each of the individual holograms in an angularly customized hologram set has an acceptance angle range that is centered on a discrete peak acceptance angle. The separation between the holograms' peak acceptance angles is chosen so that the acceptance angle ranges of the individual holograms overlap. The resulting cumulative acceptance angle range of each angularly customized hologram set provides a holographic lens assembly that has a wider angular bandwidth than prior holographic lenses.

Abstract: A method and system of displaying an image sequence containing a plurality of image frames to inhibit an unauthorized duplication thereof by a camera. The method includes steps of generating a pseudo-random noise sequence, and displaying the image sequence at a frame rate which is varied for successive pairs of the image frames in dependence upon the pseudo-random noise sequence. The frame rate is varied within a predetermined range about a nominal frame rate for the image sequence such that the variations are imperceptible by a human observer. The system includes a pseudo-random sequence generator (30) which generates the pseudo-random noise sequence, and a display device (36) to display the image sequence at a frame rate which is varied in dependence upon the pseudo-random noise sequence.

Abstract: Methods and systems for encoding an audio signal into a bit stream, and for recreating the audio signal from the bit stream are disclosed. In an embodiment of an encoder, a first encoder (10) symbolically encodes a substantially vocal audio signal to form a first encoded signal. A second encoder (12) symbolically encodes a substantially nonvocal audio signal to form a second encoded signal. A multiplexer (14) multiplexes the first encoded signal and the second encoded signal to form the bit stream. In an embodiment of a decoder, a demultiplexer (80) extracts an encoded vocal signal and an encoded nonvocal signal from the bit stream. A first decoder (82) forms a decoded vocal signal based upon the encoded vocal signal. A second decoder (84) forms a decoded nonvocal signal based upon the encoded nonvocal signal. A mixer (86) combines the decoded vocal signal with the decoded nonvocal signal to form the audio signal.

Abstract: A diamond matrix metallic mesh suppresses RF energy, and particularly side lobe energy, in a phased array antenna, while passing main beam energy. The metal mesh emulates the structure of the bond segments joining the carbon atoms in a diamond structure. The wire diamond lattice structure is placed above an array of radiating elements to absorb side lobe energy. The wire lattice structure is fabricated through use of complementary forms which compress a wire into a required unit shape. Many unit shaped wires are placed in a form which hold the wires in the proper position. Other unit shaped wires are rotated 90 degrees and attached in place to the held wires. Additional unit shaped wires are added to form the basic interlocking cube structure of the diamond lattice.

Abstract: An optical heterodyne system provides the radiation source and beam scan control of a millimeter wave (MMW) array antenna. The heterodyne system is an optical feed system to produce the MMW by mixing the optical outputs from two lasers, distribute the signal source to an array of radiating elements through a Rotman lens and optical fibers, generate the differential phase shift for beam scan in the optical domain, change the beam direction by switching the input laser being used to illuminate the Rotman lens or by varying the frequency of one of the laser sources. The feed system includes a plurality n-1 lasers spaced along the transmit side of the lens, and a center laser disposed on the center axis of the transmit side. A l:n switch receives a command input to determine which of the n-1 lasers will operate. The beat frequency between the center laser operating frequency and that of the n-1 lasers is the MMW frequency.

Abstract: An aviator's helmet-mounted display includes a visor/combiner module (14) which is configured for use with an essentially standard aviator's flight helmet (12). The helmet-mounted display also includes a conformal image source and relay optics (ISRO) module (30) which is removably attachable to the aviator's helmet. This ISRO module (30) projects an image inwardly from outside the visor/combiner module through a transparent window portion (44) thereof and out and inner surface (48) of an angulated transparent viewing portion (18,20) of the visor/combiner module (14). The image is focused at infinity and is partially reflected from the inner surface (48) to an eye (50) of the aviator so that the image is superimposed on the aviator's view of an outside scene viewed through the viewing portion (18,20).

Abstract: A light source system (10) for collecting and directing light. The light source system (10) includes light cubes (12) including an enclosure (22) substantially surrounding a light emitter (26). The enclosure includes a body (22) enclosing a cavity (24). A plurality of light pipes (32) are disposed to extend through the body into the interior of the cavity, so that the light pipes (32) carry light from inside to outside the cavity. By utilizing a plurality of these light cubes (12), the intensity of light can be controlled by combining light from a plurality of such light sources into a combiner unit (16) which combines the light from all of these sources into a single path. The intensity of light in the combiner output can be controlled by selectively turning on or off one or more of the light sources. The present invention thereby provides a high intensity light source which is rugged and easy to manufacture at low cost. The modular design provides built in redundancy and light intensity control.

Abstract: A frequency synthesizer having two atomic frequency standard inputs that is adapted to provide seamless switching or transition between the atomic frequency standard inputs with no change in the synthesizer output phase and frequency. The synthesizer includes a multichannel phase comparison system, each channel adapted for handling an atomic frequency standard input, a digital phase lock loop, a digital to analog converter, and a voltage controlled crystal oscillator which provides the synthesizer output. The phase comparison system is adapted to continually monitor the integrity of the atomic frequency standard inputs and to continually estimate the phase differences between the two atomic frequency standard inputs. The phase difference is used to estimate the proper phase and frequency offset between the primary and secondary inputs.

Abstract: A flip-chip assembly and method for reducing the stress in its metal interconnections resulting from thermal mismatch includes a detector that has a radiation sensitive circuit on a substrate that is flip-chip connected to a layer of semiconductor material that is provided with a readout circuit. The substrate has a thermal coefficient of expansion (TCE) greater than the semiconductor layer such that operating the detector over a predetermined temperature range would stress the flip-chip connections. A first compensation layer on the readout chip has a TCE greater than the substrate's, and a second compensation layer on the first layer has a TCE approximately equal to the semiconductor layer's. The materials and thicknesses of the compensation layers are selected such that the TCE of a composite structure that includes the semiconductor and compensation layers is approximately equal to the substrate's TCE to avoid the stress over the predetermined temperature range.

Abstract: A ceramic sensor comprising a thin film of Cu.sub.x Mn.sub.3-x O.sub.4 is provided that quantitatively measures the partial pressure of CO and hydrocarbon gases in a flowing system. The sensor is specific to both CO and hydrocarbon gases and is negligibly affected by the presence of the common automobile exhaust vapors NO and H.sub.2 O, within the operational temperature range from about 250.degree. to 450.degree. C. The CO/hydrocarbon sensor of the invention has other applications, such as monitoring CO and hydrocarbon levels in laboratories, mines, and industrial smoke stacks, and may be used in environments up to about 700.degree. C.

Abstract: Methods are disclosed for fabricating a monolithic array of radiation detectors and associated readout circuits, as are monolithic arrays fabricated by the methods.

Abstract: The present invention involves a method for bonding together molecularly homogeneous objects including optical and semiconductor members. In particular, such method involves forming micro-thin grooves using high precision laser ablation in one of two surfaces to be bonded together. An adhesive is then flowed into such a groove to form chemical bonding of the members. Such bonding essentially eliminates the formation of an adhesive layer in the interface between the bonding surfaces allowing optical contacting in addition to the chemical bonding.

Abstract: A surface-emitting laser system includes a laser that emits a vertically divergent beam generally parallel to the substrate on which it is formed, and a turning mirror in the path of the beam that extends up from the substrate to a level well above the laser height. The extended mirror area reflects a greater portion of the beam than prior planar designs, increasing the output efficiency and providing a smoother beam pattern. One fabrication method employs a masking and ion beam milling technique that uses an accumulation of redeposited material to form the additional mirror area, with a thick mask layer that is later removed guiding the redeposition. An alternate fabrication method involves epitaxial growth of an additional layer of material above the conventional laser epilayers, with the additional layer subsequently removed from the laser region but retained in the mirror region.

Abstract: A liquid carbon dioxide dry cleaning system that employs a rotating basket inside a dry cleaning vessel that is powered by hydraulic flow. The present invention is particularly useful as a dry cleaning system that uses liquid carbon dioxide as the cleaning agent. The dry cleaning system has a pressurized vessel containing a liquid carbon dioxide bath. The basket is disposed in the vessel and has a plurality of openings around its periphery. A plurality of roller bearings are disposed between the basket and the vessel that allow it to rotate within the vessel. A plurality of manifolds are disposed between the vessel and the basket that have nozzles that produce jets of liquid carbon dioxide that agitate the garments. The nozzles are aligned with the plurality of openings in the basket. A pump is coupled between the manifolds and the vessel for circulating the liquid carbon dioxide to produce the jets that clean the garments and rotate the basket.

Abstract: Bonding of expanded polymeric parts together to produce lost foam molds suitable for casting metallic details is accomplished by applying a non-aqueous, adhesive-free coating comprising a polar, highly dielectric component contained in a liquid vehicle to the interfacing surface of at least one of the parts to be joined. The interfacing surfaces of the parts to be joined are held in contact while the assembly is irradiated with high frequency electromagnetic energy. This energy enables the coating to dielectrically heat the mated expanded polymeric parts until a bond is effected by melting the polymeric parts and inducing expansion of the parts into one another.

Abstract: A plurality of biphase modulators (42) each modulate a sinusoidal radio frequency signal based upon a corresponding one of a plurality of bits contained in a time-dependent data word. The biphase modulators (42) form a plurality of biphase modulated signals which are communicated to a summing network (40). The summing network (40) contains a plurality of attenuators (44) which attenuate the modulated signals to form a plurality of attenuated signals. The summing network (40) combines the attenuated signals to form a radio frequency signal.

Abstract: A method of operating a liquid crystal display, and a liquid crystal display constructed to operate in accordance with the method. The liquid crystal display has a plurality of display pixels, and the method comprises the steps of (a) operating a first switch (S1) for storing a charge on a storage capacitance (C1), the charge having a magnitude selected so as to cause a desired degree of polarization of a region (pixel) of liquid crystal material; (b) operating a second switch (S2) so as to conductively couple the stored charge to the region of liquid crystal material, thereby storing a charge on a capacitance (C2) that is associated with the region of liquid crystal material; and (c) operating a third switch (S3) so as to discharge the storage capacitance and the capacitance that is associated with the region of liquid crystal material.

Abstract: A micro-dimensional coupling conductor with a shape that is customized for a particular electronic device. A fabrication method is used in which the physical dimensions of the conductor are precisely controlled with photolithographic techniques, resulting in a conductor that is more precisely tuned to the operating frequency of the device. The conductor is fabricated on an SiO.sub.2 substrate using vacuum deposition or electroplating techniques. After fabrication, the conductor is separated from the SiO.sub.2 substrate by dissolving the SiO.sub.2. Alternatively, the conductor may be fabricated on a Teflon.TM. substrate. The use of a Teflon substrate allows a user to remove the conductor from the substrate by applying a small mechanical force to the conductor.