Abstract: A semiconductor device comprises an active element and contacts that permit low-resistance external electrical connections. The active element includes an active layer formed from group II-VI elements, an n-doped layer on one side of the active it layer, and a p-doped layer on the other side of the active layer. The p-doped layer is a ZnSe-based alloy or a ZnTe-based alloy. There are electrical contacts to the n-doped layer and to the p-doped layer. The electrical contact to the p-doped layer includes a graded-alloy contact layer in epitaxial contact with the p-doped layer and whose bandgap varies from about that of the p-doped layer adjacent the p-doped layer to about zero at a location remote from the p-doped layer. The graded-alloy contact layer is a HgZnSSe-based graded-composition alloy where the p-doped layer is a ZnSe-based alloy, or a HgZnSeTe-based graded-composition alloy where the p-doped layer is a ZnTe-based alloy.
Abstract: The present invention provides a fixture (10) for coupling an optical component (12) to a machining apparatus through the use of a vacuum. The fixture includes a base (34) having means for coupling the fixture (10) to a machine and defining an aperture (50) communicable with a vacuum source, a fixture (60) sealably coupled to the base (34), and a pad (92) disposed on the fixture (60). The fixture (60) further includes an inner surface (64), an outer surface (66), and a passage (68) extending therebetween. The fixture is coupled to the base such that the inner surface (64) of the fixture (60) cooperates with the base (34) to define a cavity (62). The pad (92) is disposed on the fixture (60) to surround the passage (68) communicating with the cavity (62) and to securely and sealingly connect an optical component (12) to the fixture (60) when the cavity (62) is subjected to a negative pressure.
Abstract: A signal processing in the element (SPRITE) thermal imaging system (20) is provided which has an electronic zoom. The system has an optics and scanning assembly (24) that scans energy from a scene (26) onto an array of SPRITE detectors (28) which generate a plurality of analog signals (30) that are proportional to the flux of infrared light received by each of the SPRITE detectors (28). The optics and scanning assembly (24) scans at a rate which is based on an optics and scanning assembly timing scheme and a digital scan converter (32) processes the analog signals (30) and generates a resultant digital output (34) for image production of the scene. The digital scan converter (32) processes the analog signals based upon a digital scan converter timing scheme. A timing and control unit (40) is used for controlling synchronization and alters the timing schemes to increase resolution and sensitivity.
Abstract: Absorption coatings utilized in a detector array reduces the optical signature of an infrared detector or detector array by reducing the undesirable reflections from exposed metal surfaces and non-planar surface features within the photodetector array. The application of an absorption coating, consisting of a single layer black coating, a multi-layer dark coating, a moth-eye surface structure, or a combination of these, reduces the undesired reflected radiation for a relevant spectral range. Accordingly, the optical signature of the detector array is reduced and the problems of optical cross-talk and ghost images are eliminated.
Abstract: An array of a large number of low quality light collectors measure light generated by arrays of coherent light illuminators and rebounded from a target. The resulting data is utilized to derive the resulting speckle pattern which in turn is Fourier transformed to reconstruct the target image.
Abstract: An energy beam threat discrimination system (110) adapted for use with laser beam energy (134). The system (110) includes an first detector (114) for detecting a first laser signal. A second detector (112) detects a coherent laser signal. A timer circuit (124, 126) establishes a time interval between the detection of the first laser signal and the detection of the coherent laser signal and provides an output (130) in response thereto. A control circuit (128, 130) determines, based on the output (130), if the first laser signal and/or the second laser signal is threatening. In a specific embodiment, the first detector (114) provides an event detection flag (118) as an output in response to the detection of a first laser signal. The first detector (114) includes a high sensitivity laser light detector (142), a pre-amplifier (144), and an analog threshold circuit (146). The coherent detector (112) provides a coherent detection flag (116) as an output in response to the detection of the coherent laser signal.
Abstract: A torque motor includes an annular, cylindrically symmetric support base, and a plurality of electromagnet coils affixed to the support base at regular intervals around a cylindrical circumference of the support base. There is additionally an annular, generally cylindrical, rotationally movable rotor ring overlying the support base and having an inner surface, and a plurality of permanent magnets affixed to the inner surface of the rotor ring at regular intervals around a cylindrical circumference of the rotor ring. The number of permanent magnets is even and equal to the number of electromagnet coils, and the permanent magnets are arranged in alternating polarities around the circumference of the rotor ring. In a preferred form, there are six of each type of magnet, spaced equidistantly around the circumference of the respective rings.
Abstract: An assembly comprises a base (16) and a thin optical substrate (10) having a light reflective first surface (12) and an opposite back surface (14). At least one actuator (20) is mounted to said base and has a moving end (21) associated with the back surface of said optical substrate. A metallic button (18) is interposed between and connected through associated joints respectively to the moving end (21) of the actuator and said back surface (14) of the optical substrate to protect the actuator to substrate connection.
Abstract: An array 1 of photodiodes 2 is comprised of a Group II-VI material, such as HgCdTe, which may be selectively doped to form a plurality of diode junctions. Array 1 is comprised of a plurality of photodiodes 2 which are disposed in a regular, two dimensional array. Incident IR radiation, which may be long wavelength, medium wavelength or short wavelength (LWIR, MWIR or SWIR) radiation, is incident upon a surface of the array 1. The array 1 comprises a radiation absorbing base layer 3 of Hg.sub.1-x Cd.sub.x Te semiconducting material, the value of x determining the responsivity of the array to either LWIR, MWIR or SWIR. Each of the photodiodes 2 is defined by a mesa structure, or cap layer 3; or the array 1 of photodiodes 2 may be a planar structure. Each of the photodiodes 2 is provided with an area of contact metallization 4 upon a top surface thereof, the metallization serving to electrically couple an underlying photodiode to a readout device.
March 29, 1988
Date of Patent:
August 10, 1999
Charles A. Cockrum, Peter R. Bratt, David R. Rhiger, Owen K. Wu
Abstract: A method and apparatus for testing elliptical mirrors is provided which reduces the length of the test apparatus by half, provides for precise location of the focus of the interferometer beam, and precise measurement of the distance between foci of the elliptical mirror under test. A small reflective sphere (10) with an optical passageway (15) through its center is used to locate the focal point (f.sub.2) of the interferometer (5) within interferometric precision. A plane mirror (30) is placed half way between the focal points of the ellipse (20) under test with one of the elliptical foci coincident with the interferometer focal point (f.sub.2). The elliptical mirror (20) under test is placed with reflective concave surface facing away from the interferometer (5) to receive light reflected from the plane mirror (30). The optical passageway (15) is sized to emit a volume of light to fill the elliptical mirror surface (22) after reflection from the plane mirror (30).
Abstract: An IR focal plane array (IR-FPA) includes an IR radiation detector (11a) having a plurality of IR radiation responsive photodetectors (PDs) and a readout integrated circuit (11) that includes a plurality of unit cells arranged in an N.times.M matrix. Each unit cell has an input coupled to an output of one of the IR radiation responsive photodetectors. The IR-FPA further includes M column amplifiers, preferably CTIAs, individual ones of which have an input that is coupled through one of N switches (.phi.tr) to individual ones of the N unit cells. A charge integrating capacitance in each unit cell is formed by a charge well underlying one (.phi..sub.1) of a plurality of transfer gates coupled between individual ones of the N unit cells that are coupled to one of the M column amplifiers.
Abstract: A vacuum package (20) is fabricated by providing a package base (22) with a device (32) affixed to the interior of the package base (22), and a package lid (42). An activatable getter material (54) is deposited onto a preselected region of either the interior (48) of the package lid (42) or that portion of the package base (22) which does not have the device (32) affixed thereto. The deposited getter material (54) is deposited at a temperature such that it is activated during deposition. The vacuum package lid (42) is sealed to the vacuum package base (22). The steps of depositing and sealing are conducted in an evacuated vacuum chamber without exposing the interior to atmosphere.
June 11, 1997
Date of Patent:
July 13, 1999
Adam M. Kennedy, Charles E. Sarver, Ronald L. Williams
Abstract: A liquid crystal projector and color beamsplitter that comprises a single X-cube beamsplitter that transmits both incident and exit light beams. One half of the beamsplitter divides incident white light into three primary colors, and the other half of the beamsplitter combines the primary colors to produce white light that is used for projection. More specifically, the projector comprises a light source for projecting white light, and the color beamsplitter is disposed to receive the white light. The beamsplitter comprises four (right angle) prisms that each comprise a base and two sides, and that are disposed such that the sides of the prisms are adjacent each other. The incident white light is separated by the prisms and coupled along three separate light paths corresponding to red, green and blue light paths. Apparatus such as a plurality of mirrors, or an optical link, for example, are provided for coupling the red, green and blue light back toward the beamsplitter.
Abstract: An assembly (22) comprises an optical substrate having a light reflective first surface (12) and an opposite back surface (14). At least one actuator stem (25) having a moving end (21) is provided and is associated with the back surface of the optical substrate. The optical substrate back surface has at least one integrally formed undercut button (19) and an actuator button (18) with a given thickness (T). The integrally formed button is connected to the actuator stem by an epoxy joint (38) which is distanced from the back surface by at least the dimension of the given thickness.
Abstract: A borophosphosilicate glass is deposited on a substrate (50) by heating the substrate (50), and contacting the substrate with a mixture of the gases tetramethylcyclotetrasiloxane, trimethylborate, trimethylphosphite, and oxygen, without the presence of a carrier gas. The first three of the gases are produced from liquid sources by controlled vaporization and flow. The gases react at the heated substrate (50) to deposit the glass upon the substrate. In a reactor (52) for depositing the glass, the tetramethylcyclotetrasiloxane and trimethylborate are introduced at a gas inlet location (79), and the trimethylphosphite and oxygen are heated and introduced at another gas inlet location (90). The tetramethylcyclotetrasiloxane and trimethylborate mixture flows toward the location where the trimethylphosphite and oxygen are introduced, and whereat the gases are mixed. This gaseous mixture flows past the heated substrate (50) to deposit the glass thereon.
Abstract: A three-dimensional stereovision imaging system (20) adapted for use with a polarizing filter (22). The inventive system (20) includes a stereovision projector (24) for generating a projection (26) of alternating left and right images. A polarizer (30) polarizes electromagnetic energy corresponding to the images (26) and provides a polarized image (34) in response thereto. A twist liquid crystal screen (28) controlled by a twist liquid crystal controller (36) rotates the plane of oscillation of the polarized image (40) by a first twist angle synchronized with the alternating left and right images. Polarizing glasses (42) direct the polarized image (40) from the twist liquid crystal (28) into alternate eyes in response to the polarization state of the polarized image (40). In a specific embodiment, the polarizing glasses (42) have first (44) and second (46) eye-pieces with first (44) and second (46) linear polarizers, respectively.
Abstract: A drive circuit (18) is provided that utilizes a power supply (30) to generate an output voltage that effects a precise displacement in a physical device. The drive circuit (18) includes storage circuitry (26) having a capacitive load (54) for storing the output voltage, a supply switch (34) connected the to the storage circuitry (26), the power supply (30), and control circuitry (22) that controls the supply switch (34) in response to an input signal. The control circuitry (22) controls the supply switch (34) in response to the input signal such that a supply voltage (31) from the power supply (30) is intermittently applied to the capacitive load (54) of the storage circuit (26) for generation of the output voltage that is used to effect a precise displacement in a physical device.
Abstract: A system and method for multimodal interactive speech training include selecting a modality (10) corresponding to various sensory stimuli to present non-native vocabulary elements (12) to an individual to train the individual to immediately respond (16) to a presented word, situation, or data without performing a time-consuming literal translation or other complex cognitive process. The system and method include speech synthesis, speech recognition, and visual representations of non-native vocabulary elements to promote rapid comprehension through neuro-linguistic programming of the individual.
Abstract: A beamsplitter (70) for separating a beam of light (48, 90, 92) into three frequency bands (94, 96, 98) corresponding to a first color (94), a second color (98), and a third color (96) adapted for use with a beam of white light (92). The inventive beamsplitter (70) includes first (78) and second (80) surfaces for reflecting the first color of light (94) and for transmitting the second color of light (98). A third (82) and fourth (84) surface reflect the second color of light (96) and transmit the third color of light (98). A glass support structure (72) supports the first (78), second (80), third (82), and fourth (84) surfaces in a predetermined configuration. The configuration is chosen so that the first color of light (94) is directed in a first direction (94), the second color of light (96) is directed in a second direction (96), and the third color of light (96) is directed in a third direction (96).
Abstract: A Group II-VI IR photodiode 10 has a passivation layer 16 overlying at least exposed surfaces of the p-n diode junction 15, the passivation layer being a compositionally graded layer comprised of Group II atoms diffused into a surface of the p-n diode junction. The passivation layer has a wider energy bandgap than the underlying diode material thereby repelling both holes and electrons away from the surface of the diode and resulting in improved diode operating characteristics. A cation substitution method of the invention includes the steps of preparing a surface to be passivated, such as by depleting an upper surface region of Group II atoms; depositing a layer comprised of a Group II material over the depleted surface region; and annealing the deposited layer and underlying Group II-VI material such that atoms of the deposited Group II layer diffuse into the underlying depleted surface region and fill cation vacancy sites within the depleted surface region.
May 11, 1988
Date of Patent:
March 9, 1999
Charles A. Cockrum, David R. Rhiger, Eric F. Schulte