Abstract: An optical reconstruction filter in the form of a phase diffraction grating (that is, a diffractive diffuser) placed between a flat panel liquid crystal color matrix display and a viewer to optically filter flat panel images and present a higher quality image to the viewer.

Abstract: A task scheduler system including an array of priority queues for use in a real time multitasking operating system including equation lists, configuration lists, a function library, input and output drivers, user-created task definition lists of major and minor tasks and interrupt handlers. The system includes task scheduling apparatus which, upon the completion of each library function, interrogates the priority queues and finds the highest priority task segment whose requested resource is available and executed, and which executes task segments in the same priority queue in round-robin fashion. The system further includes task creation apparatus and apparatus for maintaining the status of all major tasks in a system in the states of unlocked and done, unlocked and active, unlocked and waiting, locked and active, or locked and waiting.

Abstract: A multiplexer cell particularly adapted for multiplexing the output signals of photovoltaic detectors and which when appropriately connected together form a random access multiplexer for the photovoltaic detectors located in a large focal plane of a photosensing device. Each multiplexer cell includes an input circuit to which the input signal current from a detector is applied. A charge is stored in a storage well, the magnitude of which is an integration over an integration period of the input signal from a detector. The output of the input circuit is an output voltage produced by a sensor in close proximity to the storage well. The output voltage is a function of the magnitude of the charge stored during each integration period. Each multiplexer cell also includes a random access multiplexer output circuit to which the output voltage signal produced by its associated input circuit is applied.

Abstract: A system for classifying a two-dimensional object, the object having a boundary. The system includes a sensor for sensing the boundary of the object, a processor which assigns a chain code to the boundary of the object and memory for storing a plurality of chain code histograms corresponding to known two-dimensional objects. A histogram is generated from the object's assigned chain code and correlated in the processor with a chain code histogram from memory. A final ambiguity between the normalized chain code of the object and the chain code of the correlating known object is resolved through application of a Viterbi algorithm.

Abstract: A miniature, evacuated and hermetically sealed detector refrigerator assembly for use in infrared imaging systems incorporates a miniature Joule-Thomson laminar refrigerator which serves as the substrate for the detector subassembly, electrical leads, as well as the primary structural element of the assembly. The detector subassembly is positioned on the cold region of the refrigerator, surrounded by a vacuum chamber and capped by an optical window or filter as required. As a result, the detector is cooled in a small and relatively inexpensive package that can operate intermittently or continuously, as desired.

Abstract: A temperature compensation system for semiconductor digital or analog circuits where the temperature compensation is accomplished by two depletion mode MESFETs. A first MESFET is adapted to operate as a level shifter in the linear region of operation only in combination with a second MESFET adapted to operate in the saturation region of operation.

Abstract: A power supply having a dual-polarity, automatically switchable high voltage output. The power supply includes apparatus for regulating low voltage including a comparator having a programming voltage input and a feedback voltage input. The low voltage is converted by low voltage dc conversion apparatus to both negative and positive polarity high voltage dc signals proportional to the electronic signal applied to the programming input. Apparatus for switching the high voltage output by remote control is provided such that in a first switching mode the high voltage output is derived from the output of the positive polarity conversion apparatus, and in a second switching mode the high voltage output is derived from the output of the negative polarity conversion apparatus.

Abstract: A switching network for a GaAs semiconductor circuit employing four FETs. The FETs are configured in a ring pattern which is connected to two matched current sources. Also disclosed is a sample-and-hold circuit employing such a switching network.

Abstract: A laser radiation detection system is disclosed comprising phase retarding apparatus for retarding a portion of the laser radiation incident on the system, optical focusing apparatus, detector apparatus and an electrical circuit. The optical focusing apparatus focuses the incident radiation on the detector apparatus. The detector apparatus is located in the focal plane and detects the presence of laser radiation due to the uneven distribution of light caused by the interference of the retarded portion of the incident radiation with the portion that remains in phase. The detector apparatus supplies output signals in response to the incident radiation received by each detector to the electrical circuit which then compares the various outputs from the detector apparatus in pairs and outputs a signal indicating the presence of laser radiation when the sum of the differences of the detector outputs is greater than a predetermined threshold value.

Abstract: An improved composite lens is described which provides higher optical transmittance and lower weight and cost than a conventional ZnSe/ZnS doublet. A method of manufacture is also described which uses a process of chemical vapor disposition of one material (e.g. ZnSe) on a blank of another material (e.g. ZnS), combined with well-known optical machining and polishing processes to obtain the desired curvatures on the lens surfaces.

Abstract: A slider/stator device for the growth of thin film material, such as mercury cadmium telluride, in which the substrate, thin film and growth solution are kept free from impurities by use of sleeves, made, for example, from sapphire, in order to prevent contamination and adhesion of the growth solution to the slider assembly.

Abstract: An electronic force-detecting robot gripper for gripping objects and attaching to an external robot arm is disclosed. The gripper comprises motor apparatus, gripper jaws, and electrical circuits for driving the gripper motor and sensing the amount of force applied by the jaws. The force applied by the jaws is proportional to a threshold value of the motor current. When the motor current exceeds the threshold value, the electrical circuits supply a feedback signal to the electrical control circuit which, in turn, stops the gripper motor.

Abstract: A passive range measurement device and method are described which device includes a camera, onboard motion sensors, image digitizers and memories and a digital processor. The device creates a digitized image stream from successive images taken by the camera. The digital processor operates on the image stream in conjunction with information obtained from the onboard motion sensors to determine the location of a median plane through the scene, and the position of terrain detail located on that plane. By evaluating in like fashion hypothetical slices through the scene parallel to the median plane, a topographic range map of the scene may be created. This map is referenced to the position of the camera and platform, and may, therefore, be used to provide a terrain following capability.

Abstract: A backside contacted mosaic detector array which provides close detector packing in one or more directions by eliminating over the edge contacts typically used. The array uses indium or other cold-weldable metal, both as a means for fastening the array from the backside to its circuit board and as a means for providing electrical contact with each detector.

Abstract: A device for imparting a selected delay to a pulse emanating from a transmitter before the pulse is returned as a simulated radar echo to a radar altimeter receiver. The selected delay is obtained by recirculating the transmitted pulse through a fixed delay element a prescribed number of times. The system includes a control circuit, including a single-pole, double-throw electronic switch coupled to a presettable counter which may be preloaded with a count value corresponding to the number of iterations of the transmitted pulse through a closed loop including the delay elements. Upon each such traversal, the counter is decremented and when the counter generates a borrow signal, the electronic switch diverts the pulse to the altimeter's receiver. The recirculation loop also includes pulse amplifying and shaping circuitry for compensating for attenuation and distortion of the recirculating pulse.

Abstract: An isolated MOSFET analog switch control circuit is disclosed comprising in combination first and second switching MOSFETs for switching an analog input signal through the control circuit. The MOSFETs have their gates connected together at a gate junction and their sources connected together at a source junction. The control circuit further includes current source apparatus for generating a fixed enhancement voltage referenced to the source voltage of the first and second MOSFETs; and switching apparatus. The switching apparatus has a circuit control isolated from the switching MOSFETs and further has first and second switching terminals, for applying and disconnecting the current source apparatus to the control circuit such that when the current source is applied the switching MOSFETs will be turned on and when the current source is disconnected the switching MOSFETs will be turned off.

Abstract: A MOSFET transistor switch control circuit using high impedance, low offset, ground referenced control is disclosed. The invention comprises a first enhancement mode MOSFET having a drain connected to an electrical signal, and a second enhancement mode MOSFET having a gate connected to the gate of the first MOSFET, a source connected to the source of the first MOSFET, and a drain connected to an output of the switch. The invention further comprises, in combination with the above elements, current injection apparatus for injecting current into the switch control circuit, current switching apparatus for connecting and disconnecting the current injection apparatus from and to the switch control circuit, and electrical circuit apparatus for maintaining the gate voltage of the MOSFETs about equal to their source voltage when the current injection apparatus is disconnected, and for increasing the gate voltage when the current injection apparatus is connected.

Abstract: A miniature, nonevacuated, detector refrigerator assembly for use in infrared imaging systems is described. The assembly incorporates a miniature Joule-Thomson laminar refrigerator which serves as the substrate for the detector subassembly, electrical leads, as well as the primary structural element of the assembly. The detector subassembly is positioned on the cold region of the refrigerator, surrounded by two prefabricated vacuum chambers and capped by an optical window or filter as required. As a result, the detector is easily built and is cooled in an efficient manner.

Abstract: A dental floss dispenser comprising a container, a feed through tube, a twist-and-lock mechanism, and a barrel. The container is adapted to hold a reel of dental floss which is connected to a barrel. A tube is inserted into the barrel and dental floss is fed through the tube emerging at a feed through hole in a second end. The tube has a flared end cap which extends beyond the barrel tip. A twist-open-and-lock mechanism causes the flared end cap to behave in a reciprocating manner with respect to the barrel tip thereby alternately freeing and pinching the floss against the barrel tip.

Abstract: The method of distributing a signal from an input conductor to a plurality of relay terminals at known locations in the plane of a circuit board which comprises meandering said input conductor to intersect said terminals in succession while avoiding other relay contacts. The meandering conductor path gives this type of relay switching system the ability to maintain a switching system characteristic impedance, Z.sub.0, in a simple, cost effective manner.