Selected Patents Archive

A list of selected patents of Lincoln Laboratory-developed inventions available for license is periodically published. Below are patents that have been featured in past lists. For further information, contact Jack Turner of the MIT Technology Licensing Office, http://web.mit.edu/tlo/www/, at 617-253-6966, or mailto:jht@mit.edu.


Fedynyshyn, T. H., "Resist Materials for 157-nm Lithography"
U.S. Patent No. 6,468,712; issued October 22, 2002
U.S. Patent No. 6,815,145; issued November 9, 2004
Description: A radiation sensitive resin composition is described, including a photo-acid generator and an aliphatic polymer having one or more electron withdrawing groups adjacent to or attached to a carbon atom bearing a protected hydroxyl group, wherein the protecting group is labile in the presence of in situ generated acid. The radiation sensitive resin composition can be used as a resist suitable for image transfer by plasma etching, producing an etching image having high precision with high reproducibility, and with a high degree of resolution and selectivity.

Bloomstein, T. M., M. Rothschild, and M. Switkes, "Interferometric Projection System"
U.S. Patent No. 6,641,268; issued November 4, 2003

Description: A novel exposure system is described, which is capable of operating within the constraints imposed by the poor lateral spatial coherence and pointing error instabilities inherent in excimer based ultra-violet sources used in high resolution photolithography. The system is straightforward to implement, requiring only optical flats and mirrors, and overcomes the limited field sizes achievable in conventional designs using refractive and reflective elements. In addition, no diffractive elements are required to increase field size, thereby simplifying the extension of interference based lithography to shorter wavelength sources, such as 121 nm. Further, the disclosed design has twice the transmission throughput as the diffractive based approach, and features a more flexible architecture for varying the grating period.

Shaver, D.C., "Optical Imaging Systems and Methods Using Polarized Illumination and Coordinated Pupil Filter"
U.S. Patent Application Serial No. 10/626440; filed July 24, 2003

Description: A technique is described which enables dense patterns to be exposed using high numerical aperture optical lithography systems, without the loss of contrast that would normally occur due to the inherently low contrast that results from the p-polarized rays (electric field vector parallel to the plane of incidence). The technique uses both a varying polarization and a varying pupil filter in the projection optics. It allows improved contrast optical lithographic exposure using the emerging class of high numerical aperture systems, and offers the potential for improving process latitude and yield for the semiconductor industry.

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Fritze, M. and B.M. Tyrrell, "Method for Photolithography Using Multiple Illuminations and a Single Fine Feature Mask"
U.S. Patent Application Serial No. 10/447844; filed May 29, 2003
U.S. Patent Application Serial No. 11/135197; filed May 23, 2005

Description: A method is described for forming random contact patterns using a dense-only lithographic method. The advantage of this method is that the contrast and efficiency benefits of using two one-dimensional grating are realized, but only a single dense feature mask is necessary. The method can be generalized to produce a variety of feature patterns, using one mask and multiple illumination exposures with different illuminator settings. The method could help extend optical resolution limits because it is generally accepted that the most difficult imaging pattern for a given semiconductor process is a random contact array. It may be readily inserted into existing process flows and, in some cases, can offer immediate throughput enhancement for manufacturers already using dense-only contact lithography methods.

Fedynyshyn, T.H., "High Sensitivity X-Ray Photoresist"
U.S. Patent No. 6,872,504; issued March 29, 2005

Description: An improved X-ray sensitive resist formulation is described that is capable of high resolution imaging, and represents a simple material based solution to the problem of increasing resist sensitivity. It is based on the incorporation of fluorine in the polymers and photo acid generators that are employed in the resist formulation. Fluorine increases the X-ray absorbance of the resist, which leads to increased sensitivity and, consequently, higher manufacturing throughput.

Kunz, R.R., R.S. Sinta, and M. Switkes, "Optical Fluids, and Systems and Methods of Making and Using the Same"
U.S. Patent Application Serial No. 10/395703; filed March 24, 2003
Patent Convention Treaty Application Serial No. US04/09006; filed March 24, 2004
Description: A family of fluoroethers, hydrofluoroethers, and hydrofluorocarbons is described, with chemical structures optimized for use as transparent fluids to enhance the resolution of optical imaging in the wavelength range from 120 to 200 nm. The adoption of immersion imaging and/or photolithography for the manufacture of large-scale integrated circuits appears to be novel. Immersion lithography has been performed historically using wavelengths in the visible range, and using common organic oils as fluids. Also, known efforts are under way to develop an immersion photolithography process for use at 193 nm.

Clark, H.R., Jr., and B.S. Aherne, "Method for Producing Semiconductor Particles"
U.S. Patent No. 5,690,807, 25 Nov. 1997
Description: The invention provides a method for producing semiconductor particles in which a semiconductor material of the type for which particles are desired is placed in an electrolytic solution of an anodic cell. The anodic cell is configured with a cathode also positioned in the electrolytic solution. The electrolytic solution of the anodic cell includes an etchant and a surfactant that is characterized by an attractive affinity for the semiconductor material. To produce semiconductor particles from the semiconductor material, an electrical potential is applied between the semiconductor material in the electrolytic solution and the cathode in the electrolytic solution to anodically etch the semiconductor material. During the etch process, particles of the semiconductor material form and are encapsulated by the surfactant. This method for producing semiconductor particles uses an uncomplicated apparatus and procedure that results in inexpensive and high-volume production of particles of a semiconductor material. 

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Bozler, C.O., and S. Rabe, "Spatial Light Modulator"
U.S. Patent No. 5,784,189, 21 July 1998
Description: A spatial light modulator formed of a moveable electrode which is disposed opposite a fixed electrode and is biased to roll in a preferred direction upon application of an electric field across the electrodes to produce a light valve or light shutter. In one embodiment, the moveable electrode is restrained at one end and coils about the fixed end in a preferential roll direction. The bias is achieved by inducing anisotropic stress or anisotropic stiffness. 

Swanson, E.A., and S.R. Chinn, "Apparatus and Method for Accessing Data on Multilayered Optical Media"
U.S. Patent No. 5,784,352, 21 July 1998
Description: Apparatus and methods for accessing data on a multilayered optical storage medium. The apparatus uses the time-of-flight of illumination directed to and reflected by the layers of the optical medium to access data stored on a desired layer of the medium. More particularly, alterations in illumination reflected from the desired layer are detected to access data stored on the layer. In accordance with embodiments of the invention utilizing interferometric techniques, the time-of-flight of a reference illumination is adjusted to cause interference of the reference illumination with the illumination reflected from the layer which contains the data to be accessed. Alternatively, and in accordance with embodiments of the invention utilizing non-interferometric techniques, the time-of-flight of illumination reflected by the layer which contains the data to be accessed is selected to permit data stored on the desired layer to be accessed. 

Leger, J.R., and W.C. Goltos, "Method and Apparatus for Efficient Concentration of Light from Laser Diode Arrays"
U.S. Patent No. 5,787,107, 28 July 1998
Description: A lens system for use with a linearly arrayed light beam including a first optical element for receiving and redirecting different portions of the linearly arrayed light beam to different locations on an imaginary plane so as to generate a two-dimensional pattern of light beams on the imaginary plane; and a second optical element located at the imaginary plane and aligned with the two-dimensional pattern of light beams for redirecting each of the light beams of the two-dimensional pattern of light beams to any arbitrary direction. 

Delanoy, R.L., "Machine Learning Apparatus and Method for Image Searching"
U.S. Patent No. 5,793,888, 11 Aug. 1998
Description: A computer model is interactively trained to recognize patterns of spectral or textural features in imagery. The interactively trained module is based on techniques of knowledge-based image processing and an approach that uses interest images to provide a means of continuous feedback of module performance to the user. The user, in turn, responds by indicating where the module is making mistakes. A set of user-indicated examples and counter examples form the inputs to a machine learning program called Functional Template Learning. The trained module is exportable as an independent agent to search large databases for matching patterns. Following retrieval of images having matching patterns, a user can further refine the agent’s performance by indicating where mistakes have been made. The overall search tool employing the trained module is capable of prescreening and highlighting images, significantly reducing the workload of analysts attempting to detect regions or objects in imagery. 

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Robbins, W.L., J.S. Haggerty, D.D. Rathman, W.D. Goodhue, G.B. Kenney, A. Lightfoot, R.A. Murphy, W.E. Rhine, and J. Sigalovsky, "Net-Shape Ceramic Processing for Electronic Devices and Packages"
U.S. Patent No. 5,801,073, 1 Sept. 1998
Description: A method of producing electronic device packages is provided, consisting of the steps of shaping a package preform and heating the package preform in a nitrogen-containing atmosphere to nitride the package preform. The shaped package preform may consist of package base, sidewall, conductor, resistor, or capacitor components. The package base and sidewall components may be formed of silicon powder. The method also accommodates the step of inserting a semiconducting material into the package preform and heating the semiconducting material component along with the package preform. The inserted semiconducting material component may be processed to define active electronic device areas on the component either before or after the step of heating the shaped package preform and inserted semiconducting material component. The package production methods of the invention provide the ability to produce reaction bonded structural and dielectric package components by way of a nitriding process that causes minimal overall shrinkage of the package. As a result, reaction formed electronic device packages of the invention may be shaped to finished dimensions before the nitriding process with complicated and tight-tolerance geometries of package structural, conducting, resistive, and capacitive components. The package production methods of the invention also provide the ability to interleave electronic device and packaging manufacturing sequence steps, resulting in increased manufacturing efficiency, as well as improved performance in the devices and packages produced. Device substrates or partially fabricated devices may be embedded into semi-finished packages, whereby completion of device fabrication coincides with completion of package fabrication. This makes possible the fabrication of active devices and circuits in a fully packaged environment. 

Liau, Z.-L., and R.C. Williamson, "Curved Surfaces Formed by Etching and Thermal Processing"
U.S. Patent No. 5,807,622, 15 Sept. 1998
Description: A smooth contoured structure is formed from a planar surface by etching mesas of equal height into the surface and heat treating the structure to mass transport material above the desired contour to fill in voids below the desired contour. In an alternate embodiment, an optical element is formed using a patterned layer of sacrificial material and thermally treating the sacrificial layer to form a precursor contour line. The line is then transformed onto a substrate and smoothed to form the optical element. 

Fenn, A.J., "Thermodynamic Adaptive Phased Array System for Activating Thermosensitive Liposomes in Targeted Drug Delivery"
U.S. Patent No. 5,810,888, 22 Sept. 1998
Description: A thermodynamic therapy system including a thermally activated drug delivery system which is provided within the bloodstream of a patient under therapy, and an adaptive phased array radiation transmission system operable for transmitting and focusing radiation to heat a treatment area within the patient. The drug delivery system releases a selected drug at the treatment area in response to the treatment area being heated by the focused radiation. 

Shirley, L.G., "Methods and Apparatus for Remotely Sensing the Orientation of an Object"
U.S. Patent No. 5,811,826, 22 Sept. 1998
Description: A method and apparatus for remotely sensing the orientation of an object takes advantage of the fact that, for flat surfaces, a change in radiation frequency illuminating the object produces a global translation at the detector plane of the speckle pattern reflected from the object. An object is illuminated with radiation of two different frequencies and the corresponding speckle patterns are compared to determine the magnitude and direction of shift from the first speckle pattern to the second. The magnitude and direction of the speckle pattern shift indicates the orientation of the object. 

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Geis, M.W., E.R. Brown, S.J. Eglash, and C.L. Dennis, "Resonant-Tunneling Transmission Line Technology"
U.S. Patent No. 5,815,240
Description: Resonant-tunneling transmission lines in the various architectures rely on discrete or continuous resonant-tunneling heterostructures to actively modify propagating logic signals. One embodiment utilizes amplification of logic signals to counteract ubiquitous losses and distortion associated with any transmission medium. Basically, the logic signal is incrementally reamplified and reshaped as it propagates along the transmission line. Another embodiment is directed to a clocking system that transmits a signal represented by a sinusoid. Then, in proximity to the logic gates or modules, the sinusoid is converted into a square wave that actually clocks the gates and other logic structures. The inventive active transmission line naturally performs this feature, thus enabling clock signal transmission over longer links coupled with sinusoid-to-square wave conversion in a limited area. Still other embodiments implement step or continuous variations in the physical width of the resonant-tunneling transmission line. By manipulating the transmission line width of successive sections of the line, isolation in addition to the logic operation of the input signals is achievable in a simple monolithic circuit design. Further embodiments are directed to oscillator circuits and the control of the characteristics of the generated periodic signal. 

Boroson, D.M., "Signal Generation Using Optical Pulses"
U.S. Patent No. 5,822,103, 13 Oct. 1998
Description: An optical modulator includes an optical pulse train generator that forms an optical pulse train of a predetermined frequency at a generator output. The optical modulator also includes an optical pulse train modifier having a first input optically coupled to the output of the pulse train generator, a second input, and an optical output. The modifier produces a modulated optical pulse train related to a signal appearing at the second input and having an optical sub-carrier frequency related to the predetermined frequency of the optical pulse train at the first input.

Moores, J.D., "Rational-Harmonic Apparatus and Technique"
U.S. Patent No. 5,828,682, 27 Oct. 1998
Description: A modulated cavity including a cavity; a modulation source; and a modulator located with said cavity and in electrical communication with said modulation source. The modulation source overdrives the modulator with a period of modulation Tmod substantially equal to Troundtrip (n+(p/q))-1. n, p, and q are integers. Troundtrip is the period of a pulse making one round-trip in the cavity. In one embodiment of the invention, p and q are relatively prime. In another embodiment of the invention, the optical response of the modulator includes the qth harmonic of (1/Tmod). In yet another embodiment of the invention, p/q is an integer. In still yet another embodiment of the invention p/q is a rational number. 

Hall, K.L., and K.A. Rauschenbach, "Apparatus and Method for Comparing Optical Bits"
U.S. Patent No. 5,831,731, 3 Nov. 1998
Description: An optical bit error tester for testing an optical device. The optical bit error tester, in one embodiment, includes an optical bit pattern generator, an optical beam divider in communication with the optical bit pattern generator, the optical device being tested, and an optical XOR gate. The optical XOR gate in one embodiment includes a first input port in communication with the beam divider and a second input port in communication with the optical device being tested. The optical XOR gate produces an output signal at its output port in response to changes introduced by the optical device under test in the optical bit pattern produced by the optical bit pattern generator. In one embodiment the optical XOR gate includes a non-linear optical loop mirror. 

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Song, W.S., "Quadrature Sampling System and Hybrid Equalizer"
U.S. Patent No. 5,841,811, 24 Nov. 1998
Description: A quadrature sampling system and method (BQS) and a hybrid quadrature sampling and channel equalization system and method (BQS/EQ) which convert input signals to baseband inphase and quadrature signal components. The BQS system includes an inphase signal channel including a first set of K filters, and a signal summer which sums the outputs of the first set of K filters to produce the inphase signal component; a quadrature signal channel including a second set of K filters and a signal summer which sums the outputs of the second set of K filters to produce the quadrature signal component; and a controlled switch which provides input samples to the inphase and quadrature signal channels so that each filter of both channels receives one input sample of each sequence. The BQS/EQ system includes first and second sets of signal processing filter pairs, each pair including an inphase and a quadrature filter. A controlled switch alternately switches input samples between the first and second sets of signal processing filter pairs and applies selected ones of the input samples to each filter pair so that each filter pair receives one input sample of each sequence. The outputs of the filters pairs of each set are selectively provided to the inphase and quadrature signal summers. 

Hollis, M.A., D.J. Ehrlich, R.A. Murphy, B.B. Kosicki, D.D. Rathman, R.H. Mathews, B.E. Burke, M.D. Eggers, M.E. Hogan, and R.S. Varma, "Optical and Electrical Methods and Apparatus for Molecule Detection"
U.S. Patent No. 5,846,708, 8 Dec. 1998
Description: A method and apparatus are disclosed for identifying molecular structures within a sample substance using a monolithic array of test sites formed on a substrate upon which the sample substance is applied. Each test site includes probes formed therein to bond with a predetermined target molecular structure or structures. A signal is applied to the test sites and certain electrical, mechanical and/or optical properties of the test sites are detected to determine which probes have bonded to an associated target molecular structure. 

J.B. Bernstein, "Technique for Producing Interconnecting Conductive Links"
U.S. Patent No. 5,861,325, 19 Jan. 1999
Description: A method for providing a conductive link between conductive materials, e.g., metals, separated by a nonconductive material, e.g., a silicon based glass material. In a preferred embodiment a single pulse of laser energy is applied to at least one of the conductive materials to produce mechanical strain therein which strain initiates a fracturing of the non-conductive material so as to provide at least one fissure therein extending between the conductive materials. The laser energy pulse further causes at least one of the conductive materials to flow in such fissure to provide a conductive link between the conductive materials. 

Betts, G., "Sub-Octave Bandpass Optical Remote Antenna Link Modulator and Method Therefor"
U.S. Patent No. 5,867,295, 2 Feb. 1999
Description: An electro-optical modulation device comprises a first Mach-Zehnder interferometric modulator. This modulator has balanced optical power in each arm to intensity modulate an optical carrier signal in response to an information signal. The invention also includes a second Mach-Zehnder interferometric modulator that is in a cascade connection with the first modulator and also has balanced optical power in each arm. This second modulator receives the optical carrier signal from the first modulator and also intensity modulates the optical carrier signal in response to the information signal. In another embodiment, the electro-optical modulation device comprises an electro-optical modulator, for intensity modulating an optical carrier in response to an electrical signal, and a reflective termination. The termination reflects the intensity modulated optical carrier signal to travel back through the electro-optical modulator. As a result, the modulation effect of the modulator is effectively doubled. Either embodiment finds application in applications that involve bandwidths of less than one octave, for which the embodiments can be easily optimized. The best examples are links for remote antennas, the most notable exception being cable television. For these sub-octave-bandpass links, second-order distortion does not present a problem since these spurious signals fall outside the band of interest. As a result, the second-order distortion control constraint can be sacrificed in an effort to negate third-order distortion and remediate other problems. This trade-off is not available in broadband cable applications. 

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Spitzberg, R.M., "Non-Contact Surface Temperature, Emissivity, and Area Estimation"
U.S. Patent No. 5,868,496, 9 Feb. 1999
Description: Method and apparatus for non-contact temperature, emissivity and area estimation for gray and non-gray (uniform and non-uniform surface emissivity) are disclosed. Optical power measurements are obtained for radiation from a surface of interest in multiple wavelength bands. These power measurements are used to generate an expression for surface emissivity as a function of unknown temperature and surface projected area. At each of series of trial temperatures and areas within a predetermined range of physically plausible values, a value for emissivity at each measured wavelength is obtained. A best fit between these emissivity data points and a selected model emissivity function is obtained by least-squares minimization. The trial temperature and area which yield both the smallest minimum sum of squares and an emissivity value within predetermined physical constraints are concluded to be the temperature and projected surface area. An expression for the emissivity of the surface as a function of wavelength is also thus obtained. The invention applies as well for the case when the surface of interest has a known area. The invention includes a means of correcting for reflected background radiation by modeling it as part of the measured optical power at each measurement wavelength. Optical power measurements are taken in the environment of the surface from a calibration source having a known temperature and known emissivity characteristics, thus allowing the background radiation source effects to be characterized and excluded from the temperature estimation. 

Shirley, L.G., and M.S. Mermelstein, "Apparatus and Methods for Surface Contour Measurement"
U.S. Patent No. 5,870,191, 9 Feb. 1999
Description: Apparatus and methods of measuring position information, typically the depth coordinate, of a point on the surface of an object. In one embodiment, the apparatus includes two sources of radiation positioned to illuminate the point on the surface of the object with radiation from each of the sources. The radiation from each of the sources is coherent with respect to the radiation from the other source. A control system changes the phase of the radiation from at least one of the sources relative to the phase of the radiation from the other source as measured at the point on the surface of the object. A detector is positioned to receive radiation scattered by the point, and a processor, in communication with the detector, calculates position information in response to the change in phase of the radiation from the source and the received radiation scattered by the point on the surface of the object. 

Kushner, L.J., "Composite Direct Digital Synthesizer"
U.S. Patent No. 5,878,335, 2 Mar. 1999
Description: A low-power digital frequency synthesizer combining direct digital frequency synthesis techniques with serrodyne frequency translation principles to produce a wideband frequency response with high spectral purity. A conventional direct digital synthesizer is used to generate a high-resolution analog carrier signal from a low-speed digital clock signal. The carrier signal is phase modulated by a low-resolution signal generated from a high-speed digital clock signal. The modulation signal is a higher frequency signal than the carrier signal. The phase modulation is accomplished by exact decoded gain elements. The spectral purity of the resulting high-resolution output signal is unobtainable by conventional direct digital synthesizers, while providing significant power savings. 

Kushner, L.J., "Balanced Digital-to-Analog Converter"
U.S. Patent No. 5,880,689, 9 Mar. 1999
Description: A balanced digital-to-analog converter has improved half-wave symmetry and glitch energy due to the use of a pair of single-ended DACs. By subtracting the outputs from a pair of DACs operating 180° out-of-phase, even-order distortion and glitch energy can be cancelled out. When the balanced DAC is employed in a high-speed direct digital synthesizer, the alias second-harmonic, which is the dominant spur, is dramatically decreased without increasing the noise level of the circuit. 

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Savoye, E.D., A.M. Waxman, R.K. Reich, B.E. Burke, J.A. Gregory, W.H. McGonagle, A.H. Loomis, B.B. Kosicki, R.W. Mountain, A.N. Gove, D.A. Fay, and J.E. Carrick, "Low-Light-Level Imaging and Image Processing"
U.S. Patent No. 5,880,777, 9 Mar. 1999
Description: An imaging system is provided for imaging a scene to produce a sequence of image frames of the scene at a frame rate, R, of at least about 25 image frames per second. The system includes an optical input port, a charge-coupled imaging device, an analog signal processor, and an analog-to-digital processor (A/D). The A/D digitizes the amplified pixel signal to produce a digital image signal formatted as a sequence of image frames each of a plurality of digital pixel values and having a dynamic range of digital pixel values represented by a number of digital bits, B, where B is greater than 8. A digital image processor is provided for processing digital pixel values in the sequence of image frames to produce an output image frame sequence at the frame rate, R, representative of the imaged scene, with a latency of no more than about 1/R and a dynamic range of image frame pixel values represented by a number of digital bits, D, where D is less than B. The output image frame sequence is characterized by noise-limited resolution of at least a minimum number, NM, of line pairs per millimeter, referred to the charge-coupled imaging device pixel array, in an imaged scene as a function of illuminance of the input light impinging the charge-coupled imaging device pixels. 

Gleason, K.K., S.J.H. Limb, E.F. Gleason, H.H. Sawin, and D.J. Edell, "Chemical Vapor Deposition of Fluorocarbon Polymer Thin Films"
U.S. Patent No. 5,888,591, 30 Mar. 1999
Description: Provided are methods for forming a fluorocarbon polymer thin film on the surface of a structure. In one method, a monomer gas is exposed to a source of heat having a temperature sufficient to pyrolyze the monomer gas and produce a source of reactive CF2 species in the vicinity of the structure surface. The structure surface is maintained substantially at a temperature lower than that of the heat source to induce deposition and polymerization of the CF2 species on the structure surface. In another method for forming a fluorocarbon polymer thin film, the structure is exposed to a plasma environment in which a monomer gas is ionized to produce reactive CF2 species. The plasma environment is produced by application to the monomer gas of plasma excitation power characterized by an excitation duty cycle having alternating intervals in which excitation power is applied and in which no excitation power is applied to the monomer gas. The monomer gas employed in the methods preferably includes hexa-fluoropropylene oxide. The monomer gas pyrolysis and plasma excitation methods can be carried out individually, sequentially, or simultaneously. Flexible fluorocarbon polymer thin films can thusly be produced on wires, twisted wires, neural probes, tubing, complex microstructures, substrates, microfabricated circuits, and other structures. The thin films have a compositional CF2 fraction of at least about 50%, a dielectric constant of less than about 1.95, and a crosslinking density of less than about 35%. 

Swanson, G.J., and R.P. Gale, "Illumination System for Color Displays"
U.S. Patent No. 5,889,567, 30 Mar. 1999
Description: Binary optics are used in an illumination system for a color projection display. In one embodiment a broad spectrum light source illuminates a multilevel optical phase element which disperses the broad spectrum light from the light source by diffraction. A display having a number of pixel elements, each capable of transmitting a predetermined spectral region, is positioned within the near field region of the multilevel optical phase element so as to receive the light dispersed by the multilevel phase element. 

Eggers, M.D., M.E. Hogan, K.L. Beattie, J. Shumaker, D.J. Ehrlich, and M. Hollis, "MultiSite Detection Apparatus"
U.S. Patent No. 5,891,630, 6 Apr. 1999
Description: A method and apparatus for identifying molecular structures within a sample substance using an array having a plurality of test sites upon which the sample substance is applied. Each test site includes a probe formed therein to bond with an associated target molecular structure. An electrical signal is applied to the test site and the electrical properties of the test sites are detected to determine which probes have bonded to an associated target molecular structure. 

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Kunz, R.R., "Polymeric Anti-Reflective Compounds"
U.S. Patent No. 5,891,959, 6 Apr. 1999
Description: Anti-reflective coatings and methods for forming these anti-reflective coatings are disclosed that have a polymer chemistry and optical characteristics suitable for suppressing the light that reflects off a circuit substrate during a photolithographic process. These anti-reflective coatings include a phenolic polymer material and an epoxide-containing polymer material that can be combined in a select proportion to form a thermally curable polymeric anti-reflective coating. The select proportions of the combined materials tailors the optical characteristic of the anti-reflective coating to attenuate energy about a select range of wavelengths. 

Marino, R.M., "Method and Apparatus for Imaging a Scene Using a Light Detector Operating in Nonlinear Geiger-Mode"
U.S. Patent No. 5,892,575, 6 Apr. 1999
Description: A method and apparatus for imaging a scene. The method and apparatus are capable of resolving 3D spatial structure within the scene. The apparatus includes a light source, a timing system and a detector system. The light source emits pulses of light toward the object or target scene being imaged. In one embodiment, the light source is a laser. In another embodiment, the detector system includes an optical system and a monolithic array of light detectors operating in nonlinear Geiger-mode. The optical system collects a portion of the light scattered off of objects in the target scene and directs the collected light toward the array of light detectors. In another embodiment, the detector system includes an optical system and a single light detector operating in non-linear Geiger-mode. In this embodiment, the optical system scans the target scene, collects a portion of the light scattered off objects in the target scene and directs the collected light toward the light detector. 

Moores, J.D., "Polarization Desensitizer"
U.S. Patent No. 5,894,532, 13 Apr. 1999
Description: A polarization desensitizing method and apparatus including a polarization analyzer separating a polarized input pulse into two orthogonally polarized components separated in time; and a nonlinear switch integrating the power of the two orthogonally polarized components over a predetermined time and producing an output pulse having a predetermined polarization. In one embodiment the polarization desensitizer includes a polarization analyzer in communication with a data source providing data pulses; a pulse generator; and a polarization converting switch in communication with both the polarization analyzer and the pulse generator, the polarization converting switch producing output pulses of a known polarization in response to the data pulses. 

Harman, T.C., "Superlattice Structures Particularly Suitable for Use as Thermoelectric Materials"
U.S. Patent No. 5,900,071, 4 May 1999
Description: A superlattice structure comprising alternating layers of material such as (PbEuTeSe)m and (BiSbn)n where m and n are the number of PbEuTeSe and BiSb monolayers per superlattice period. For one superlattice structure the respective quantum barrier layers may be formed from electrical insulating material and the respective quantum well layers may be formed from semimetal material. For some applications superlattice structures with 10,000 or more periods may be grown. For example, the superlattice structure may comprise alternating layers of (Pb1-yEuyTe1-zSez)m and (BixSb1-x)n. According to one embodiment, the superlattice structure may comprise a plurality of layers comprising m layers of (Pb1-yEuyTe1-zSez)m and n layers of Bi0.9Sb0.1, where m and n are preferably between 2 and 20, grown on a BaF2 substrate with a buffer layer of PbTe separating the substrate and the superlattice structure. For other applications the superlattice structure may be formed from alternating layers of (Pb1-yEuyTe1-zSez)m (quantum barrier layers) and (Pb1-xSnxTe1-ySey)n (quantum well layers). 

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Verghese, S., E.R. Brown, and Q. Hu, "Photoconductive Optical Correlator"
U.S. Patent No. 5,900,624, 4 May 1999
Description: An optical correlator for correlating incident optical signals is described. The correlator comprises a transmission line in close juxtaposition to a photoconductor. The photoconductor may be positioned within the transmission line. The transmission line and the photoconductor may be monolithically integrated on a substrate. The optical correlator has an electrical nonlinear response to the incident optical signals that results from a voltage divider formed from the combination of the transmission line and the photoconductor. The electrical nonlinear response is proportional to a second-order intensity autocorrelation function g(2)(t). The response time of the electrical nonlinear response is less than the width of the narrowest pulse of the optical signals and may be less than twenty picoseconds. 

Shirley, L.G., and G.R. Hallerman, "Method and Apparatus for Detecting Relative Displacement Using a Light Source"
U.S. Patent No. 5,900,936 4 May 1999
Description: An apparatus and method for measuring the surface deformation or displacement in objects. In one embodiment the apparatus includes an interference pattern generator which projects an interference pattern onto a detector mounted to the surface which is to be measured. As the surface deforms, the detector moves and sweeps across the interference pattern. By noting the changes in the light intensity, the deformation or displacement in the surface at the detector may be determined. In another embodiment, both the detector and the interference pattern generator are located on the surface and as the surface deforms, the relative change in the surface at the detector and the relative deformation or displacement of the surface at the interference pattern generator may be determined. In another embodiment a plurality of detectors and interference pattern generators are positioned to map the deformation or displacement of the surface at many locations on the surface. 

Weiss, J.A., "Planar Gyrator"
U.S. Patent No. 5,903,198, 11 May 1999
Description: In a planar gyrator, parallel transmission lines are positioned proximal to a magnetized gyrotropic substrate. Input and output transducers couple the ends of the transmission lines to corresponding input and output ports. The input and output transducers are configured to excite first and second partial wave fields on the transmission lines of similar or different phases respectively. The wave fields, in turn, interact gyromagnetically with the substrate, such that the resultant difference in phase change for a first wave propagating from the first to the second port and a second wave propagating from the second to the first port is an odd-integer multiple of 180 degrees. Alternatively, if the magnetization of the substrate is reversed, the phase of a wave propagating from the first to the second port is changed by 180 degrees. The planar gyrator is amenable to application in miniaturized planar microwave devices, for example as a magnetically controlled phaser or switch, or as a component in a circulator or isolator implemented in planar microwave technology.

Burke, B.E., and B.B. Kosicki, "Interconnection Technique for Hybrid Integrated Devices"
U.S. Patent No. 5,904,495, 18 May 1999
Description: A hybrid integrated circuit and method of fabricating a hybrid integrated circuit. A first wafer is provided having a first surface with a first electrical contact for a first active circuit associated therewith and a second surface. A second wafer is provided having a third surface with a second electrical contact for a second active circuit associated therewith and a fourth surface, the second wafer being chemically thinned at the fourth surface. The first and second wafers are bonded together at an interface between the first and third surfaces such that the first and second electrical contacts are relatively aligned with one another. The fourth surface of the second wafer is processed to define an access via to both the first and second contacts. An electrical interconnection is formed between the first and second contacts within the access via so that the first and second active circuits are electrically interconnected. 

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Waxman, A.M., A.N. Gove, D.A. Fay, and J.E. Carrick, "Real-Time Adaptive Digital Image Processing for Dynamic Range Remapping of Imagery Including Low-Light-Level Visible Imagery"
U.S. Patent No. 5,909,244, 1 Jun. 1999
Description: An imaging system is provided for imaging a scene to produce a sequence of image frames of the scene at a frame rate, R, of at least about 25 image frames per second. The system includes an optical input port, a charge-coupled imaging device, an analog signal processor, and an analog-to-digital processor (A/D). The A/D digitizes the amplified pixel signal to produce a digital image signal formatted as a sequence of image frames each of a plurality of digital pixel values and having a dynamic range of digital pixel values represented by a number of digital bits, B, where B is greater than 8. A digital image processor is provided for processing digital pixel values in the sequence of image frames to produce an output image frame sequence at the frame rate, R, representative of the imaged scene, with a latency of no more than about 1/R and a dynamic range of image frame pixel values represented by a number of digital bits, D, where D is less than B. The output image frame sequence is characterized by noise-limited resolution of at least a minimum number, NM, of line pairs per millimeter, referred to the charge-coupled imaging device pixel array, in an imaged scene as a function of illuminance of the input light impinging the charge-coupled imaging device pixels. 

Bernstein, J.B., "Technique for Producing Interconnecting Conductive Links"
U.S. Patent No. 5,920,789, 6 Jul. 1999
Description: Conductive links are provided between conductive materials, e.g., metals, separated by a nonconductive material, e.g., a silicon-based glass material. In a preferred embodiment, a single pulse of laser energy is applied to at least one of the conductive materials to produce mechanical strain therein which strain initiates a fracturing of the nonconductive material so as to provide at least one fissure therein extending between the conductive materials. The laser energy pulse further causes at least one of the conductive materials to flow in such fissure to provide a conductive link between the conductive materials. Preferably, the nonconductive material is formed in layers such that an interface between the layers controls the fissures. 

Horn, M.W., "Vapor Deposition of Polymer Films for Photolithography"
U.S. Patent No. 5,925,494, 20 Jul. 1999
Description: The invention provides a method for vapor-depositing a polymer film having constituents that are synthesized during the deposition and that can therefore be customized by time-dependent process control during the deposition. In the vapor-deposition process, a hydrocarbon precursor is reacted with an oxygen-containing precursor in a plasma environment. The plasma reaction synthesizes O—H bonds and forms a polymer having O—H bonds, C—C bonds, and C—Hx bonds. Preferably, the hydrocarbon and oxygen-containing precursors are employed in a ratio selected such that the resulting polymer film has a selected level of oxygen constituency providing a corresponding selected ratio of O—H bond concentration to C—Hx bond concentration. The precursor ratio is preferably varied as a function of time during the plasma reaction to result in a corresponding distribution, e.g., a depth-dependent distribution, of O—H bonds in the film. The vapor-deposited polymer film provided by the invention is particularly well-suited as an all-dry positive-tone silylation photoresist because the vapor-deposition process can custom-synthesize a constituent hydroxyl group concentration and distribution in the photoresist film for a given photolithographic application. 

Misra, P.N., "Clock-Aided Satellite Navigation Receiver System for Monitoring the Integrity of Satellite Signals"
U.S. Patent No. 5,931,889, 3 Aug. 1999
Description: A satellite navigation receiver system detects faulty range measurement signals from navigation satellites and excludes them from future position estimates. This system includes a receiver coupled to a movable object. The receiver includes a stable clock with a constant frequency drift rate over a predetermined period of time. A processor coupled to the receiver models the behavior of the clock over a time period equivalent to the period of constant frequency drift rate. The processor then generates predicted clock bias estimates over a future period of time equivalent in length to the period modeled, generates an instantaneous clock bias estimate using satellite signals, and determines the difference between the instantaneous clock bias estimate and a predicted instantaneous clock bias estimate. If the difference does not fall within an acceptable limit, one or more signals are determined to be faulty. When at least five satellites are in view, the processor determines which satellites have generated the faulty signals by generating sets of position and clock bias estimates and performing four- and three-dimensional estimation to determine consistency of the sets. An inconsistent set suggests the existence of a malfunctioning satellite. Signals from malfunctioning satellites are excluded from future position estimates. 

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Bernstein, J.B., "Technique for Producing Interconnecting Conductive Links"
U.S. Patent No. 5,940,727, 17 Aug. 1999
Description: A method for providing a lateral conductive link between conductive elements, e.g., metals, placed on a first nonconductive material, wherein a second nonconductive material is placed on said first non-conductive material to form an interface there between in a region between the conductive elements. Energy is applied to the conductive elements to produce mechanical strains by thermal expansion in the conductive elements which initiate a rupturing of the interface between the nonconductive materials so as to provide at least one fissure therein extending between the conductive elements. The energy applied causes a portion of at least one of the conductive elements to flow in such fissure to provide a lateral conductive link between the conductive elements. 

Fenn, A.J., "X-Ray Needle Providing Heating with Microwave Energy"
U.S. Patent No. 5,944,749, 31 Aug. 1999
Description: Electrons moving in a first direction are concentrated (e.g., magnetically) in a beam within a first tube. A converter converts the electrons to x-rays for movement to a particular position (e.g., tumor) in a patient. A fluid (e.g., water) flowing past the converter through a second tube co-axial with the first tube cools the converter. Microwave energy passes in the first direction through a third tube co-axial with the first tube. The third tube is open at the end near the converter so that the microwave energy will pass to the particular position in the patient. A second fluid (e.g., air) passing through a fourth tube coaxial with the first tube cools the tissue in direct contact with the x-ray needle. The second, third and fourth tubes may respectively have diameters of approximately 2, 3, and 4 millimeters. The microwave energy may pass into the third tube from a fifth tube transverse to the third tube. The microwave energy impedance may be approximately 50 W at the fifth tube input and approximately 5 W at the third tube input. The fifth tube is constructed to match the 50 W and 5 W impedances. A first portion of the microwave energy introduced to the third tube flows in the first direction through the third tube coaxially with the electron beam. A second portion of the microwave energy flows in a direction opposite to the first direction, is reflected by a short circuit, and then flows in the first direction in phase with the first energy portion. 

Cuomo, K.M., "Coherent Ultra-Wideband Processing of Sparse Multisensor/Multispectral Radar Measurements"
U.S. Patent No. 5,945,940, 31 Aug. 1999
Description: A radar system coherently combines signals from independent upper- and lower-sub-band radars, mutually coheres the sub-band radar signals, and performs model fitting and parameter estimation to obtain ultra-wideband data signatures from a target. Signal processing models are used to compensate for potential lack of mutual coherence between the various sub-bands. An ultra-wideband signal model is fitted to the sparse sub-band measurements to accurately characterize ultra-wideband target scattering and provide for meaningful interpolations or extrapolations outside of the measurement sub-bands. 

Weiss, J.A., D.H. Temme, and G.F. Dionne, "Tunable Resonators"
U.S. Patent No. 5,949,311, 7 Sept. 1999
Description: In a magnetically tunable resonator, a wave-guiding structure comprising an electromagnetic frequency filter, or component of such a filter, is placed in sufficient proximity with a magnetic structure so as to be gyromagnetically coupled therewith. The resonator is supportable of two fundamental normal modes of propagation which, in the absence of magnetic interaction, are even and odd with respect to the resonator center plane of symmetry. Each normal mode possesses a spectrum of resonance frequencies. When the magnetic structure is magnetized, the formerly even and odd modes become mixed due to gyromagnetic interaction, and the resulting wave fields become elliptically polarized. With appropriate design such that the identities of the modes are preserved under conditions of resonance, this in turn results in a nonreciprocal reinforcement action in the resonator, which leads to the desired shift in resonance frequency in at least one of the two normal modes. The device is especially attractive to application in miniaturized planar microwave devices, for example MMICs, in conferring small size and weight, simplicity of structure, low power required for tuning, capability of fixed, continuous or digitally stepped frequencies, and low-loss high-Q performance; applicable with superconducting or conventional metallic conductors. 

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Swanson, E.A., and S.R. Chinn, "Method and Apparatus for Performing Optical Measurements Using a Rapidly Frequency-Tuned Laser"
U.S. Patent No. 5,956,355, 21 Sept. 1999
Description: An optical system, in one embodiment including an external-cavity frequency-tuned laser having a tunable longitudinal cavity mode and a center tunable wavelength. The external-cavity frequency-tuned laser includes an optical cavity, an optical gain medium positioned within the optical cavity, and a rapid tuning wavelength selecting device positioned to receive light from the optical gain medium and adapted to return selected wavelengths of light to the optical gain medium. The external-cavity frequency-tuned laser is substantially continuously tunable and the tunable wavelength selecting device tunes the center wavelength of the external-cavity frequency-tuned laser at the same rate as the longitudinal cavity mode of the external-cavity frequency-tuned laser is tuned. In another embodiment the optical system includes an interferometer in optical communication with the external-cavity frequency-tuned laser. The interferometer is adapted to project a portion of light from the external-cavity frequency-tuned laser onto a sample, to receive light altered by the sample, and to combine light reflected from the sample and the light from the external-cavity frequency-tuned laser. A detector positioned to receive the combined light from the interferometer and to generate a signal in response thereto. A processing unit in communication with the detector performs digital signal processing to extract spatial information related to the sample in response to the signal from the detector. 

Bozler, C.O., and S. Rabe, "Spatial Light Modulator"
U.S. Patent No. 5,959,763, 28 Sept. 1999
Description: A spatial light modulator formed of a moveable electrode which is disposed opposite a fixed electrode and is biased to roll in a preferred direction upon application of an electric field across the electrodes to produce a light valve or light shutter. In one embodiment, the moveable electrode is restrained at one end and coils about the fixed end in a preferential roll direction. The bias is achieved by inducing anisotropic stress or anisotropic stiffness. 

Wolfson, M., B. Forman, R. Hallowell, M. Moore, R. Delanoy, and E. Marciniak, "Method and Apparatus for Tracking of Organized Storms"
U.S. Patent No. 5,959,567, 28 Sept. 1999
Description: A method and apparatus for tracking of organized storms using weather radar images. An image filter approximating the envelope of the organized storm radar image is used to improve tracking of the large scale storm features. The image filter is repeatedly rotated to different orientations at each point in the weather radar images to produce filtered images. The filtered images are provided to an image tracker to generate an array of track vectors. Application of the array of track vectors to the unfiltered image generates a predicted weather radar image. 

Geis, M.W, N.N. Efremow, K.E. Krohn, J.C. Twichell, and T.M. Lyszczarz, "Surface-Emission Cathodes"
U.S. Patent No. 5,973,451, 26 Oct. 1999
Description: The surface-emission cathodes of the invention are constructed so that the cathode body has a free surface over which electrons are efficiently accelerated after injection from a conductive contact. The junction between the free surface and the contact has the property that the height of the barrier to tunneling from the contact to floating surface states associated with the free surface of the cathode body is lower than both the barrier to emission from the contact to vacuum and the barrier to injection from the contact into the conduction band of the cathode body material. Thus under an applied potential, electrons are injected from the contact into floating surface states associated with the free surface. After acceleration, electrons leave the free surface, either emitted to vacuum or injected into another medium. 

Geis, M.W., J.C. Twichell, T.M. Lyszczarz, and N.N. Efremow, "Field Emitters of Wide-Bandgap Material"
U.S. Patent No. 5,990,604, 23 Nov. 1999
Description: Improved field-emission devices are based on composing the back contact to the emitter material such that electron-injection efficiency into the emitter material is enhanced. Alteration of the emitter material structure near the contact or geometric field enhancement due to contact morphology gives rise to the improved injection efficiency. The devices are able to emit electrons at high current density and lower applied potential differences and temperatures than previously achieved. Wide-bandgap emitter materials without shallow donors benefit from this approach. The emission characteristics of diamond substitutionally doped with nitrogen, having a favorable emitter/vacuum band structure but being limited by the efficiency of electron injection into it, show especial improvement in the context of the invention. The injection-enhancing contacts can be created by combining the emitter material with an appropriate metal compound and annealing or by conventional dry anisotropic etching or ion bombardment techniques.

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