Abstract: A technique is provided for automatically initiating reset of a digital detector. Generally, a digital detector has an array of rows and columns of pixels, read out electronics and scan electronics, that are configured to generate and transmit signals based upon radiation impacting the detector. The technique incorporates an automatic reset circuit that provides state machines to implement a reset if no readout or scrub command is received within a set time interval, or if communication with a readout control circuit is not available. The technique also includes methods for monitoring inputs, and resetting the charge on the rows and columns of pixels.

Abstract: A technique is provided for automatically initiating reset of a digital detector. Generally, a digital detector has an array of rows and columns of pixels, read out electronics and scan electronics, that are configured to generate and transmit signals based upon radiation impacting the detector. The technique incorporates an automatic reset circuit that provides state machines to implement a reset if no readout or scrub command is received within a set time interval, or if communication with a readout control circuit is not available. The technique also includes methods for monitoring inputs, and resetting the charge on the rows and columns of pixels.

Abstract: A method for detecting cut data lines in an imaging array having a detector including an array of pixels for measuring radiation, and a plurality of data line contacts is provided. The method includes the steps of initializing pixels of the imaging array which includes a plurality of data lines including at least one uncut data line and at least one cut data line, wherein each cut data line is electrically connected to at least one of the plurality of data line contacts and at least one uncommitted contact. The method further includes determining a signal level for the uncut data lines, measuring a signal level of each data line in the plurality of data lines, and determining a number of cut data lines and a number of uncut data lines by using the signal levels received from each data line in the plurality of data.

Abstract: A method of forming a planar photosensitive device, such as an array of APDs, includes the steps of doping a substantially planar block of n type semiconductor material with a p type dopant in accordance with a selected pattern to form a plurality of p type wells in the block surrounded by a foundation of n type semiconductor material. Each p type well corresponds to an APD pixel and is disposed so as to respectively adjoin a first surface of the block and such that a respective p-n junction is formed between the p type material in the well and the n type material foundation. Each APD pixel further comprises depletion layer profile modification means such that the peak surface electric field of the p-n junction in each well is substantially less than the bulk electric field of the same p-n junction.

Abstract: A method of fabricating a high density thin film circuit includes the step of bonding a high density connector having a plurality of electrical connection lines with a wafer having a plurality of electrical contact pads arranged in a pattern with a pitch less than about 100 .mu.m so that an electrical coupling is formed between the wafer contact pads and connector electrical connection lines. The step of forming the electrical coupling comprises pyrolysis of an adhesive disposed between the high density connector and said wafer. The electrical coupling between the contact pads and electrical connection lines is formed by directing a laser beam on the area in which the electrical coupling is to be formed so as to cause thermal decomposition of the adhesive to form a conductive carbon material; portions of the wafer contact pads and the connector electrical connection lines are also welded to the conductive carbon material.

Abstract: An interferometric switch for spatially switching either linearly polarized or unpolarized externally derived beams of substantially coherent light includes an optical input unit for dividing an externally derived light beam into a constituent beam pair. An optical phase modulating device includes a nematic liquid crystal pixel for selectively shifting the relative phase of the constituent beam pair. An output unit cooperates to combine respective components of the constituent beam pair along coincident collinear paths so as to form a respective output light beam directed along a selected one of first and second output axes, according to the relative phase imparted by the phase-modulating device. The phase modulating device may comprise a cascading arrangement of pixel stages which can respectively provide a selected incremental phase-shift to each constituent beam passing therethrough.

Abstract: A method of fabricating a high density thin film circuit includes the step of bonding a high density connector having a plurality of electrical connection lines with a wafer having a plurality of electrical contact pads arranged in a pattern with a pitch less than about 100 .mu.m so that an electrical coupling is formed between respective ones of the wafer contact pads and corresponding ones of connector electrical connection lines. The step of forming the electrical coupling comprises pyrolysis of an adhesive disposed between the high density connector and said wafer.

Abstract: A method of forming a planar semiconductor device, such as an array of APDs, includes the steps of doping a substantially planar block of n type semiconductor material with a p type dopant in accordance with a selected pattern to form a plurality of n type wells in the block surrounded by a foundation of p type semiconductor material. Each n type well is disposed so as to respectively adjoin a first surface of the block and such that a respective p-n junction is formed between the n type material in the well and the p type material foundation. The n type semiconductor material in each well has a substantially constant concentration of n type dopant throughout the n type material; the concentration of p type dopant in the foundation has a positive gradient extending from the p-n junction towards the second surface such that the peak surface electric field of the p-n junction in each well is less than the bulk electric field of the same p-n junction.

Abstract: A planar photosensitive device, such as an array of APDs, includes a planar block of n type semiconductor material having a plurality of p type wells in the block surrounded by a foundation of n type semiconductor material. Each p type well corresponds to an APD pixel and is disposed so as to respectively adjoin a first surface of the block and such that a respective p-n junction is formed between the p type material in the well and the n type material foundation. Each APD pixel further comprises depletion layer profile modification means such that the peak surface electric field of the p-n junction in each well is substantially less than the bulk electric field of the same p-n junction.

Abstract: An interferometric optical switching device for switching substantially coherent light beams includes a plurality of interferometric switching cells arranged in matrix form. Each interferometric switching cell is independently controllable to selectively direct received light beams along at least a selected one of two axes. The device can be three-dimensionally expanded to increase the number of ports to which the light beams can be selectively switched, in which case the matrices can share integrally constructed interferometric switching cells. The device is further capable of providing bidirectional communication between predetermined ones of the ports thereof.

Abstract: A compact optical switching unit includes a spatial light modulator coupled to a delay assembly such that incident light beams are respectively selectively directed along either a direct path or a delay path dependent on the linear polarization of the light beam. The delay assembly includes a light deflection device, such as a polarizing beam splitter, coupled to a delay path apparatus, such as mirror prisms or fiber optic cable. A compact and readily fabricated cascade of optical switching units includes polarizing beam splitter blocks and polarization rotation switch blocks, a portion of which constitutes the polarizing beamsplitters and spatial light modulators in respective optical switching units sequentially optically coupled. Delay path apparatuses disposed along an axis orthogonal to both the axis of beams passing along a direct path through polarizing beam splitter switches on the direct path and the axis between respective optical switching units result in a compact optical architecture.

Abstract: A compact optical switching unit includes a polarization independent beamsplitter switch (PIBS) coupled to a delay path apparatus such that incident light beams are respectively selectively directed along either a direct path or a delay path dependent on the the manipulation of the polarization of polarized constituent light beams in the PIBS. The delay path apparatus is typically a mirror prism or fiber optic cable disposed such that light deflected onto the delay path traverses a longer distance than light passing along the direct path and thus a particular light beam can be selectively time delayed by controlling the PIBS to direct the beam into desired delay paths in a cascade of optical signal switching units. A compact and readily fabricated cascade of optical switching units includes PIBS blocks, a portion of which constitutes the PIBS in respective optical switching units sequentially optically coupled.

Abstract: A radiation imaging device has a plurality of scintillator elements that are each optically coupled to a plurality of internal gain photodetectors. Each photodetector is electrically coupled to a respective detect and hold circuit which amplifies and stores the pulse generated by the photodetector; the stored pulses are sampled via a multiplexed switching arrangement to allow the stored signal from each detect and hold circuit to be processed to produce a digitized imaging signal which corresponds to the energy level of, and location on the array of, the detected incident radiation. The digitized imaging signal is supplied to display memory and analysis equipment for the device.

Abstract: A radiation imager comprises a scintillator mated to a photodetector array. An enclosure ring is disposed around the outer sidewalls of the scintillator and an enclosure ring cover hermetically bonded to the ring extends across the scintillator to form a chamber sealably enclosing the scintillator. The enclosure ring cover is substantially impervious to moisture, is radiation transmissive, and minimizes scattering of light from the scintillator. The cover may be optically reflective or light absorptive. The chamber is evacuated to draw the cover in towards the photodetector array and thus to ensure close contact between the cover and the scintillator and between the scintillator and the photodetector array. Desiccant can be disposed in the chamber to provide additional protection against moisture absorption by the scintillator.

Abstract: A liquid crystal display device includes an entrance polarizer to provide light which is linearly polarized in a first selected direction and a first birefringent film to convert the linearly polarized light from the entrance polarizer to elliptically polarized light having a selected ellipticity. At least one liquid crystal cell having an ellipticity equal to the selected ellipticity receives the light propagating from the first birefringent film; the liquid crystal cell includes first and second parallel-facing transparent plates which sealably contain a quantity of liquid crystal material. The liquid crystal material comprises at least a first molecule immediately adjacent the first transparent plate which is oriented in the first selected direction and at least a second molecule immediately adjacent the second transparent plate which is oriented in a second selected direction.

Abstract: A liquid crystal device includes at least one pixel electrode, formed on a transparent substrate, and having opposed first and second sides edges. A transparent cover glass is disposed in parallel alignment with the substrate and has a ground plane formed thereon opposite to the pixel electrode. A multiplicity of liquid crystal molecules is sealably contained between the substrate and cover glass. In one embodiment, a field control electrode (FCE) is formed on the substrate proximate to the pixel electrode first side edge. A voltage of proper polarity and magnitude may be applied to the FCE relative to the ground plane electrode to avoid a disclination line (mobile inversion wall) proximate to the pixel electrode first side edge when another voltage of proper polarity and magnitude is applied to the pixel electrode relative to the ground plane electrode.

Abstract: A thin film FET switching element, particularly useful in liquid crystal displays (LCDs) employs particular materials and is fabricated via a particular process to ensure chemical compatibility and the formation of good electrical contact to an amorphous silicon layer while also producing FETs with desirable electrical properties for LCDs. These materials include the use of titanium as a gate electrode material and the use of N.sup.+ amorphous silicon as a material to enhance electrical contact between molybdenum source and drain pads and an underlying layer of amorphous silicon. The process of the present invention provides enhanced fabrication yield and device performance.

Abstract: Light blocking spacer material is disposed so as to at least partially cover the data and/or gate lines in a variety of liquid crystal display (LCD) devices. The material prevents spurious visual information from being displayed as a result of high RMS supply voltages applied to the data lines, such voltages acting to switch liquid crystal material at inopportune times and to thus degrade the displayed image. The light blocking material also enhances the displayed image by acting as a spacer between the front and back LCD device panels to insure uniform cell spacing. Light blocking material is also employed at the same time to prevent light from reaching light sensitive thin film field effect transistors (FETs) which operate to switch each cell or to establish gray levels therein. The light otherwise has a tendency to discharge the LCD cell, also hampering device function.

Abstract: A thin film FET switching element, particularly useful in liquid crystal displays, employs a set of special materials to ensure compatibility with the indium tin oxide of a pixel electrode layer used as transparent conductive material in liquid crystal display devices. These materials include the use of titanium as a gate electrode material and the use of aluminum as a material to enhance electrical contact between source and drain pads and an underlying layer of amorphous silicon. The apparatus and process of the present invention provide enhanced fabrication yield and device reliability.

Abstract: Redundancy is provided in the data and gate lines of the liquid crystal display device for improved reliability and greater fabrication yield. The data lines in particular are preferably fabricated in a multilayer structure with two conductive layers sandwiching a narrow insulating strip. The presence of the insulating strip permits the upper conductive line to be formed without step jumps which can exhibit a tendency for poor electrical connection. The upper and lower conductive layers of the data line are in contact for the length of the lower data line, contact being made on either side of the narrower insulating strip. Similar redundancy, without the necessity of providing an intermediary insulating layer is also provided for the gate lines. The redundancy provided in the present invention is particularly suitable for fabrication methods employed in thin film FET driven LCD devices.