Patents Assigned to Litton Systems Canada Limited
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Patent number: 5930591Abstract: In a method of fabricating a high resolution low voltage flat panel radiation imaging sensor having a radiation transducer having a radiation conversion layer of amorphous semiconductor and an electrode on one side thereof and an array of pixels arranged in rows and columns on an opposite side thereof, each pixel including a pixel electrode and storage capacitor and a charge readout device connected to the pixel electrode and the storage capacitor, the improvement comprising the step of shining light on selected regions of the radiation conversion layer which are aligned with the pixel electrodes to thereby crystallize the regions, resulting in a plurality of low resistivity and high charge mobility crystallized regions where the semiconductor material has been exposed to the light surrounded by high resistivity and low charge mobility regions where the semiconductor material has not been exposed to the light, for preventing lateral charge diffusion between respective ones of the low resistivity and high charType: GrantFiled: April 23, 1997Date of Patent: July 27, 1999Assignee: Litton Systems Canada LimitedInventor: Zhong Shou Huang
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Patent number: 5917210Abstract: A novel thin film transistor (TFT) structure for minimizing parasitic capitances on both the drain and source electrodes. According to a first embodiment, a triple gate TFT is provided with an open gate structure in which the source and drain electrodes are non-overlapping with the top gate electrode. A pair of bottom gate electrodes being aligned respectively with the first gap between the gate and source and the second gap between the gate and drain. According to a second embodiment of the invention, a full transfer TFT switch is provided having a source, a drain, a bottom gate and semi-conductor layer therebetween, and a partial top gate overlapping a portion of the drain and a portion of the semiconductor layer for creating a generally triangular-shaped charge density distribution in the semiconductor layer for moving channel electrons toward the source electrode.Type: GrantFiled: June 30, 1997Date of Patent: June 29, 1999Assignee: Litton Systems Canada LimitedInventors: Zhong Shou Huang, John Wright
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Patent number: 5869837Abstract: A radiation imaging system comprising a capacitive coupling radiation detector for directly converting incidence radiation to electrical charges, a storage capacitor for storing the generated charges, a read-out switch for periodically outputting the charges stored on the storage capacitor, and a reset switch for periodically re-setting the radiation detector.Type: GrantFiled: March 31, 1997Date of Patent: February 9, 1999Assignee: Litton Systems Canada LimitedInventor: Zhong Huang
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Patent number: 5780858Abstract: An electromagnetic radiation imaging device comprising an energy absorbing layer overlying an array of thin film transistors (TFTs). each of the thin film transistors incorporates a dual gate. The lower gate provides row selection, while the upper gate of the same device modulates current conducted by the transistor. By utilizing dual gates, a reduction in the number of transistors is achieved over prior art imaging devices, thereby increasing production yield. Furthermore, the use of dual gate transistors provides increased versatility in choosing the bias point of the transistors.Type: GrantFiled: October 4, 1996Date of Patent: July 14, 1998Assignee: Litton Systems Canada LimitedInventors: David Waechter, Surendra Singh
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Patent number: 5589965Abstract: A wide viewing-angle twisted nematic liquid crystal display is provided. The wide viewing-angle is achieved by the application of properly aligned retardation films in between a 90.degree. twisted nematic liquid crystal cell and one of two polarizers, as well by doping the liquid crystal with an appropriate amount of dichroic dye molecules. These two additional elements not only increase the viewing-angle but also improve the chromaticity of the display. The retardation films convert the polarization state of the transmitted light of the liquid crystal cell to a more linearly polarized light in order to achieve higher contrast ratio at -45.degree. and +45.degree. scanning direction relative to the rub direction of the back substrate of the cell. The dichroic dye molecules operate on the absorption principle and further improve the contrast ratio along a 90.degree. scanning direction. By combining both elements in a liquid crystal display, a much wider viewing-angle is achieved.Type: GrantFiled: June 23, 1994Date of Patent: December 31, 1996Assignee: Litton Systems (Canada) LimitedInventors: Birendra Bahadur, Kam H. Wan
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Patent number: 5260606Abstract: Presented is a device and method for providing a means of driving capacitive cells, such as those comprising suspended particle light valve windows, with a squarewave voltage signal at a select frequency with high efficiency and low power requirements. The invention uses an inductive circuit in parallel with the capacitive load of the capacitive cell, a dc voltage source, and a fast switching means connected to timely control the polarity of the voltage source to the capacitive cell.Type: GrantFiled: January 31, 1992Date of Patent: November 9, 1993Assignee: Litton Systems Canada LimitedInventor: Willard A. Young
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Patent number: 5246042Abstract: A method and apparatus are disclosed for controllably filling a confined optical cavity primarily with a volatile fluid suspension where a controlled slight pressure is used to force the fluid into the cavity and is followed by adjusting the equilibrium with a slight negative pressure or possibly atmospheric pressure applied at an exit port to the cavity. This method and apparatus is particularly suited to the filling of light valves which are configured with parallel plates positioned by very small distances between one another to create the cavity which is to be filled with the volatile fluid suspension.Type: GrantFiled: November 20, 1992Date of Patent: September 21, 1993Assignee: Litton Systems Canada LimitedInventor: James F. Farrell
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Patent number: 5241995Abstract: A method and apparatus are disclosed for controllably filling a confined optical cavity primarily with a volatile fluid suspension where a controlled slight pressure is used to force the fluid into the cavity and is followed by adjusting the equilibrium with a slight negative pressure or possibly atmospheric pressure applied at an exit port to the cavity. This method and apparatus is particularly suited to the filling of light valves which are configured with parallel plates positioned by very small distances between one another to create the cavity which is to be filled with the volatile fluid suspension.Type: GrantFiled: September 24, 1991Date of Patent: September 7, 1993Assignee: Litton Systems Canada LimitedInventor: James F. Farrell
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Patent number: 5235451Abstract: This invention teaches a method of making reliable electrical contact between the driver IC circuits and the TFT matrix array by the use of wire bond connections which are short and which facilitate compact location of the drivers to the frame of a flat panel display or directly to the panel substrate.Type: GrantFiled: September 9, 1992Date of Patent: August 10, 1993Assignee: Litton Systems Canada LimitedInventor: Keith D. Bryan
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Patent number: 5146355Abstract: A transflective liquid crystal display provides a high quality color image and efficient energy utilization. A layer of liquid cyrstal material is controlled by a transparent electrode matrix. A matrix of (primary color emitting) phosphors is aligned with a matrix of transparent electrodes for controlling the shuttering of the liquid crystal layer. A source of fluorescent energy excites the phosphors. A first dichroic filter and a second dichroic filter are located behind the liquid crystal layer. The first filter reflects untraviolet light and transmits visible light while the second filter transmits ultraviolet light and reflects visible light. The two filters are arrayed so that the phosphors are efficiently energized by the ultraviolet light source while ambient illumination is utilized, the display thereby providing both transmissive and reflective modes of operation.Type: GrantFiled: March 18, 1991Date of Patent: September 8, 1992Assignee: Litton Systems Canada LimitedInventors: John C. Prince, James F. Farrell
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Patent number: 5143433Abstract: This invention presents a way to provide night vision viewing compatibility of backlit electrooptic modulated light valve or LCD displays designed for daylight viewing. Liquid crystal displays (LCD) designed with backlighting systems which provide a high brightness, good contrast display under daylight conditions are inappropriate for use in dark, night time conditions where viewing of the display is desired utilizing electronic night vision equipment. This invention describes improvements to standard backlighting displays which through the utilization of arrays of low-level intensity light sources such as secondary fluorescent light sources, miniature incandescent lamps or light emitting diodes, the general means used in daylight vision can be turned off and the secondary low-level lighting sources achieve a minimum intensity acceptable for night vision electronic viewing.Type: GrantFiled: November 1, 1991Date of Patent: September 1, 1992Assignee: Litton Systems Canada LimitedInventor: James F. Farrell
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Patent number: 5019808Abstract: A liquid crystal display provides a high quality color image and efficient energy utilization. A layer of liquid crystal material is controlled by a transparent electrode matrix. A matrix of (primary color emitting) phosphors, each in alignment with a transparent electrode, is fixed to a surface of a fiber optic plate. A source of fluorescent energy excites the phosphors. A filter located behind the fiber optic plate reflects visible light, both ambient and that emitted from the phosphors. The fiber optic late acts as a relay lens and prevents cross pixel color contamination while the generation of backlight by the phosphor conversion of fluorescent to visible energy is a highly efficient process.Type: GrantFiled: November 14, 1988Date of Patent: May 28, 1991Assignee: Litton Systems Canada LimitedInventors: John C. Prince, James F. Farrell
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Patent number: 4857801Abstract: A display for full color video includes light emitting diodes (LED's) arranged to increase LED density and thereby achieve enhanced resolution. The matrix is of the type that includes a plurality of physically separate, addressable dice fixed to a substrate. The display of the invention achieves increased density by utilizing dice of at least two distinct predetermined heights which are positioned onto the substrate in a predetermined pattern whereby the heights of adjacent dice differ. In this way, the closeness of inter-die spacing is not limited by the size of a positioning tool for grasping dice adjacent their upper portions.Type: GrantFiled: May 28, 1987Date of Patent: August 15, 1989Assignee: Litton Systems Canada LimitedInventor: James F. Farrell
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Patent number: 4799050Abstract: A liquid crystal display provides a high quality color image and efficient energy utilization. A layer of liquid crystal material is controlled by a transparent electrode matrix that is fixed to one surface of a fiber optic plate. A matrix of (primary color emitting) phosphors, each in alignment with a transparent electrode, is fixed to the opposed surface of the plate. A source of fluorescent energy excites the phosphors. A filter located behind the fiber optic plate reflects visible light, both ambient and that emitted from the phosphors. The fiber optic plate acts as a relay lens and prevents cross pixel color contamination while the generation of backlight by the phosphor conversion of fluorescent to visible energy is a highly efficient process.Type: GrantFiled: October 23, 1986Date of Patent: January 17, 1989Assignee: Litton Systems Canada LimitedInventors: John C. Prince, James F. Farrell
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Patent number: 4793708Abstract: A symmetric fiber optic sensing coil for use in a rotation sensing device such as a gyroscope. The coil comprises a plurality of turns of a continuous strand of orthogonally wound fiber optic material. The coil may comprise either dualpole or quadrupole symmetry and may be formed on a spool having at least one aperture in each of its circular flanges. The symmetric sensing coil is minimally affected by environmental factors such as temperature, vibration and magnetic fields that can otherwise produce measurements that are indistinguishable from sensed rotation.Type: GrantFiled: March 27, 1987Date of Patent: December 27, 1988Assignee: Litton Systems Canada LimitedInventor: Bronek Bednarz