Abstract: A direction finding system for infrared radiation includes a set of three detectors uniformly positioned in an XY plane about the Z axis of a cartesian coordinate system with individual ones of the detectors having radiation detection surfaces being normal to the Z axis. A set of three mirrors have front and back reflecting surfaces which are parallel to the Z axis, the mirrors being uniformly distributed among the detectors. Signals of the detectors have magnitudes dependent on the sum of direct radiation and radiation reflected by adjoining mirrors. The detector signals are fed into computer storage to permit computation of the direction of a source of radiant energy relative to the Z axis based on a ratio of magnitudes of the signals of the detectors.

Abstract: Ground shield apparatus for improving a test jig apparatus (10) is disclosed for providing accurate and reliable evaluation of a wide variety of test devices which propagate signals having frequencies in excess of one gigahertz over a broad range of temperatures. A circular ground wall (12) encloses a multi-layer arrangement of disc-shaped dielectric layers (18, 22) which both enclose and are attached to a conductive ground plane (20). Plated-through holes (26) are deployed at the periphery of each of the discs (18, 20, 22) in order to electrically couple upper and lower ground rings (24, 25) to the ground wall (12) and the ground plane (20). External jig connectors (16) are mounted in connector holes (14) formed in the ground wall (12).

Abstract: A shearing phase difference sensor including a high energy laser source for generating adjacent coherent light beam. Samples of the beams are extracted by an extracter and directed to an optical modifier. The optical modifier, positioned for intercepting the sample beams from the extracter, diffracts the beams and produces output beams which, in turn, are directed through a lens to a detector. The detector, positioned to intercept the output beams, produces electrical signals indicative of the output beams. The electrical signals are processed by a processor which calculates the phase difference between adjacent coherent light beams. Also, disclosed is a method for measuring the phase difference between adjacent coherent light beams.

Abstract: A protective dome (14) is provided for a zoom telescope (12) which is located therein. Telescope (12) can be used as an attachment to a prime imaging system (22) such as a FLIR (forward looking infrared). The dome (14) is mounted so that its center of curvature (16) is inboard of the outer skin (18) of the aircraft in order to reduce aerodynamic drag. The objective lens (24) of the telescope (12) is decentered with respect to a common axis (29) and the lenses of the zoom lens group (26) are tilted with respect to the common axis (29) to compensate for aberrations introduced by the decentered dome (14).

Abstract: A fire sensing system utilizing fiber optics to extend the physical range of radiation sensing elements into areas and environments which are physically inaccessible to, and/or destructive of, such sensors and their associated electronic circuitry. The fiber optics are combined with signal processing circuitry to achieve reliable fire sensing systems which present particular advantages in special applications.

Abstract: A system and method is described for obtaining a spatial characterization of a particle beam, including the beam direction, position, divergence, aberrations and intensity profile. A mechanism is also provided for adjusting the beam propagation to a desired state in response to the sensed characteristics. A fiber array in the path of a neutral particle beam casts shadows which are sensed at a downstream location to characterize the beam. Various mechanisms can be used to sense the shadow positions and/or widths relative to the fibers, from which the various beam characteristics can be derived. By magnetically removing charged particles from the neutral beam shadows, the shadows can be sensed by their effect upon the secondary emission currents generated in downstream conducting sensor wires, by their effect upon the fluorescence of downstream optical fibers, or by their effect upon the thermal heating of various types of downstream heat sensors.

Abstract: Apparatus is disclosed for providing microelectronic, intra-chip and chip-to-chip interconnections in an ultra-dense integrated circuit configuration. An inverted chip carrier 36 comprises a carrier 35 between an improved interconnection device 37 and a semiconductor chip 12. The carrier 37 includes a mesa portion 52 bearing an array of conductive connectors 50 extending above ledge portions 54. Ledge terminals 56 are connected to the connectors 50 atop the mesa 52 by internal carrier conductors 51 and are connected to chip 12 through short, straight wires 58 that are coupled to chip 12 at conductive pads 60. Carrier 35 and chip 12 together form a sub-assembly 39 which mates with an array of complementary connectors 48 on the lower surface of an improved interconnection device 37. The present invention eliminates undesirable and wasteful looped wirebonds and provides substantial increases in volume available for active circuitry per planar die area.

Abstract: Method and apparatus for calibrating equipment used for testing photodiode arrays by reference to the diode under test. The diodes are illuminated with infrared radiation and different bias voltages, developed by bombardment with an electron beam, are measured at zero current. The measured voltage values are correlated with secondary emission sensor readouts to calibrate the sensor according to the specific diode being tested. Remote light emitting diodes generate the infrared radiation which is coupled to the photodiode array via optical fiber elements.

Abstract: A folded optical system is provided in the form of a telescope (20) for viewing distant objects. At least two optical elements (22, 24) have curved surfaces (32, 34) for imaging rays of radiation from a distant object. The two surfaces are positioned so as to permit a series of reflections therebetween for magnification of the resulting focal length of the optical system and diminution in the overall viewing angle so as to attenuate any light which may emanate from sources of radiation disposed off an optical axis which intercepts the object being viewed. One or more of the optical elements may be provided with apertures (30) through which rays of radiation are directed to a sensor (26) of the radiation, the sensor being positioned on a image plane to receive an image of the objects being viewed. First and second ones of the optical surface may be concave and convex, respectively, or alternatively, each optical surface may be concave with a folding mirror being utilized in the reflection of rays therebetween.

Abstract: The present invention is directed to a method and apparatus for reducing temperature variation in an infrared detector. The apparatus comprises a coldfinger for receiving thermal energy from an infrared detector. A thermal damper is also provided for conducting thermal energy from said detector to the coldfinger by one or more thermally conductive paths. A detector mount is used for combining the thermal energy flowing through the paths, thereby reducing the temperature variation in the detector.

Abstract: An afocal beam expansion system and method is described which achieves the compactness of prior art refractive systems and yet avoids the use of refractive elements with their accompanying beam scattering, adsorption and temperature sensitivity. A pointing reflector is positioned in the beam path between an expansion reflector and a collimating reflector. The small diameter input beam is directed onto the expansion reflector, which causes it to diverge, reflects off the pointing reflector, and reaches the collimating reflector. The latter element collimates the beam and reflects it back to the pointing reflector, which points the beam along a desired output axis. The expansion, pointing and collimating reflectors are positioned relative to each other such that the beam axis is altered upon each reflection from each element.

Abstract: An adaptive laser system (10) incorporates a laser (12) and a novel system and method for determining the slope distribution of a laser beam wavefront. The sensor comprises a ramp filter (16) with a continuous monotonically varying transmittance function and two intensity distribution sensors (18 and 20). Lenses (24, 26 and 28) are provided for focusing and collimating the laser beam as appropriate. A processor (22) calculates the slope distribution from the two intensity distributions obtained by the intensity sensors. The slope calculations can be used to determine commands to predistort the laser beam to approximate a desired flat wavefront at the sensor. The transmittance function of the ramp filter is linear and its spatial width is considerably larger than the expected spreading of the beam due to distortions in the wavefront.

Abstract: Apparatus for sensing the existence of a fire and providing a warning, if desired, with improved discrimination against the possibility of false alarms. Dual channel detectors are used, one detector being set to respond to incident radiation having a wavelength in the range of 0.8 to 1.1 microns while the other wavelength range is significantly displaced therefrom, being selected for wavelengths in the range from 14 to 25 microns. Reliability of true signal detection is further improved by the provision of separate flame flicker bandpass filters in the respective channels, these bandpass filters being set for different passbands. Circuits providing ratio discrimination, threshold detectors and delay circuitry are combined with the dual spectrum detectors and disparate flicker frequency filters to achieve improved performance.

Abstract: An improved transverse gas flow RF pumped waveguide laser has been developed utilizing RF discharge waveguide technology in a mid-infrared laser. A potential application has been identified in a continuous wave gas laser. For the laser, the flowing gas provides efficient cooling so that high output power per unit gain length can be achieved.

Abstract: A method and apparatus associated therewith for acquiring and maintaining a high quality communication by communication means of the type that includes a detector and focusing means for directing encoded incoming radiation to said detector. Means are provided for determining the location of said radiation upon said detector and for generating an electrical signal responsive to said location. Said electrical signal is applied to electroluminescent means so that there is produced for the user a pattern of illumination indicating the degree of alignment of said communication means with the incoming radiation.

Abstract: A method and circuit for reading out the detector signal current from an infrared focal plane array by converting the detector current into a precisely proportional charge packet which is injected into the channel of a charge-coupled device (CCD). In a preferred embodiment the circuit comprises a capacitive feedback transimpedance amplifier 30 (or similar infrared detector signal encoding circuit) coupled to a precision CCD charge-injection circuit 10 formed on a semiconducting substrate 12. A surface potential well 50 underneath a reservoir gate electrode 80 is filled with charge that is initially kept in place by a channel stop 14 and a potential barrier 62. When the detector signal is applied to signal gate electrode 60, the potential barrier 62 is lowered and a precisely proportional amount of charge fills a store potential well 48 underneath a store gate electorde 85.

Abstract: A Q-switched laser resonator is constructed in the form of an integral, one-piece assembly, thus eliminating the requirement for an optical bench to support the individual components. The integral assembly is constructed by bonding a surface of the Q-switch device to an end of the laser rod, the bonding being accomplished with a layer of transparent adhesive. Similarly, the optical coupler is bonded to the opposite surface of the Q-switch device with a layer of adhesive. The resulting laser resonator assembly is optically aligned prior to the setting of the adhesive layers such that the alignment is permanently maintained after the adhesive sets.

Abstract: A fire sensor that can perform a sophisticated analysis of the outputs of radiant energy detectors, while minimizing size, weight, and cost, by employing a microprocessor to analyze the detector outputs. In one embodiment, an Intel 2920 Signal Processor is utilized as the microprocessor. An alternative embodiment incorporates an RCA 1802 microprocessor to achieve fire sensing while discriminating against false signal radiation.

Abstract: A high pressure CO.sub.2 laser waveguide having an extended tuning range. The laser cavity is bounded by a first partially reflecting member and a second partially reflecting member, the second member comprising a reflecting mirror and a diffraction grating member used in the Littrow configuration, the grating being positioned outside the laser cavity and spaced from the second reflecting mirror a predetermined distance. The combination of the mirror and grating provides an effective grating reflectivity which is sufficient to extend the tuning range of the laser to a value not previously available.

Abstract: A unidirectional heat pipe (22) acting as a thermal diode or a heat switch, enables heat to be removed from electronic equipment (14) when temperatures outside of a missile envelope (12) are lower than those of the electronic equipment. When the temperature exterior to the missile envelope is greater than that of the electronic equipment, the heat therefrom is conducted to a package (16) containing phase change material which absorbs the heat from the electronic equipment, at which time the heat pipe acts as a thermal insulator. Heat is also removed from the PCM package by the heat pipe when exterior temperatures are lower than interior temperatures.