Patents Assigned to Digirad Corporation
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Publication number: 20070267577Abstract: A combined cold plate for RF shield is optimized both for cooling a device and also for shielding it against RF. One embodiment uses a two-part material so that it has improved thermal characteristics from one part and RF shielding characteristics from another part.Type: ApplicationFiled: May 22, 2007Publication date: November 22, 2007Applicant: DIGIRAD CORPORATIONInventor: Joel Kindem
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Patent number: 7297927Abstract: Ultra-low leakage current backside-illuminated semiconductor photodiode arrays are fabricated using a method of formation of a transparent, conducting bias electrode layer that avoids high-temperature processing of the substrate after the wafer has been gettered. As a consequence, the component of the reverse-bias leakage current associated with strain, crystallographic defects or impurities introduced during elevated temperature processing subsequent to gettering can be kept extremely low. An optically transparent, conductive bias electrode layer, serving as both an optical window and an ohmic backside equipotential contact surface for the photodiodes, is fabricated by etching through the polysilicon gettering layer and a portion of the thickness of heavily-doped crystalline silicon layer formed within, and near the back of, the substrate during the gettering process.Type: GrantFiled: August 31, 2006Date of Patent: November 20, 2007Assignee: Digirad CorporationInventors: Lars S. Carlson, Shulai Zhao, John Sheridan, Alan Mollet
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Patent number: 7256386Abstract: Ultra-low leakage current backside-illuminated semiconductor photodiode arrays are fabricated using a method of formation of a transparent, conducting bias electrode layer that avoids high-temperature processing of the substrate after the wafer has been gettered. As a consequence, the component of the reverse-bias leakage current associated with strain, crystallographic defects or impurities introduced during elevated temperature processing subsequent to gettering can be kept extremely low. An optically transparent, conductive bias electrode layer, serving as both an optical window and an ohmic backside equipotential contact surface for the photodiodes, is fabricated by etching through the polysilicon gettering layer and a portion of the thickness of heavily-doped crystalline silicon layer formed within, and near the back of, the substrate during the gettering process.Type: GrantFiled: May 10, 2004Date of Patent: August 14, 2007Assignee: Digirad CorporationInventors: Lars S. Carlson, Shulai Zhao, John Sheridan, Alan Mollet
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Patent number: 7217953Abstract: A passive mechanism suppresses injection, into any active guard regions interposed between the edge of a photodiode array chip and the outer photodiode pixels or into the outer pixels themselves, of minority carrier current generated in the physically disrupted region at the edge of the semiconductor die created by cleaving, sawing or otherwise separating the chip from the remainder of the wafer on which the die was fabricated. A thin metallic layer covers all or part of the edge region, thereby creating a Schottky barrier. This barrier generates a depletion region in the adjacent semiconductor material. The depletion region inherently creates an energy band distribution which preferentially accelerates minority carriers generated or near the metal-semiconductor interface towards the metal, thereby suppressing collection of these carriers by any active regions of the guard structure or by the photodiode pixels.Type: GrantFiled: September 28, 2004Date of Patent: May 15, 2007Assignee: Digirad CorporationInventor: Lars S. Carlson
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Patent number: 7164130Abstract: Events of interest are detected within a gamma ray detection system. Characteristics of undesired signals, including a multiplicity of events within the signal, a density of events within the signal, and other aspects are determined. The signal is filtered based on its expected characteristics. A signal which does not have the expected characteristics is rejected, and an image is formed that excludes those rejected signals.Type: GrantFiled: February 18, 2004Date of Patent: January 16, 2007Assignee: Digirad CorporationInventors: Dan Welsh, Joel Kindem, Michael Gurley, Richard L. Conwell
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Patent number: 7019783Abstract: An embedded power supply for providing a voltage on a detector module within an imaging system provides the required potential to the module from charge stored on an output capacitor. Charge on the capacitor is replenished by injecting, commonly referred to as pumping, current into the capacitor by pulses of current generated by switching mode circuitry. Charge pumping into the capacitor is efficient because energy is stored in low-loss passive components and transferred into the low-loss output capacitor through low-impedance paths. Switching noise of the power supply is eliminated by turning off the charge pumping circuit during periods when such noise would disrupt the operation of the module, for example when the module is reading out image data. The output capacitor is large enough to supply the required voltage to the module for a certain period when the capacitor is not being pumped.Type: GrantFiled: October 4, 2004Date of Patent: March 28, 2006Assignee: Digirad CorporationInventors: Joel Kindem, Lars S. Carlson
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Publication number: 20040206886Abstract: Ultra-low leakage current backside-illuminated semiconductor photodiode arrays are fabricated using a method of formation of a transparent, conducting bias electrode layer that avoids high-temperature processing of the substrate after the wafer has been gettered. As a consequence, the component of the reverse-bias leakage current associated with strain, crystallographic defects or impurities introduced during elevated temperature processing subsequent to gettering can be kept extremely low. An optically transparent, conductive bias electrode layer, serving as both an optical window and an ohmic backside equipotential contact surface for the photodiodes, is fabricated by etching through the polysilicon gettering layer and a portion of the thickness of heavily-doped crystalline silicon layer formed within, and near the back of, the substrate during the gettering process.Type: ApplicationFiled: May 10, 2004Publication date: October 21, 2004Applicant: Digirad Corporation, a Delaware corporationInventors: Lars S. Carlson, Shulai Zhao, John Sheridan, Alan Mollet
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Patent number: 6734416Abstract: Ultra-low leakage current backside-illuminated semiconductor photodiode arrays are fabricated using a method of formation of a transparent, conducting bias electrode layer that avoids high-temperature processing of the substrate after the wafer has been gettered. As a consequence, the component of the reverse-bias leakage current associated with strain, crystallographic defects or impurities introduced during elevated temperature processing subsequent to gettering can be kept extremely low. An optically transparent, conductive bias electrode layer, serving as both an optical window and an ohmic backside equipotential contact surface for the photodiodes, is fabricated by etching through the polysilicon gettering layer and a portion of the thickness of heavily-doped crystalline silicon layer formed within, and near the back of, the substrate during the gettering process.Type: GrantFiled: November 15, 2002Date of Patent: May 11, 2004Assignee: Digirad CorporationInventors: Lars S. Carlson, Shulai Zhao, John Sheridan, Alan Mollet
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Patent number: 6677182Abstract: A passive mechanism suppresses injection, into any active guard regions interposed between the edge of a photodiode array chip and the outer photodiode pixels or into the outer pixels themselves, of minority carrier current generated in the physically disrupted region at the edge of the semiconductor die created by cleaving, sawing or otherwise separating the chip from the remainder of the wafer on which the die was fabricated. A thin metallic layer covers all or part of the edge region, thereby creating a Schottky barrier. This barrier generates a depletion region in the adjacent semiconductor material. The depletion region inherently creates an energy band distribution which preferentially accelerates minority carriers generated or near the metal-semiconductor interface towards the metal, thereby suppressing collection of these carriers by any active regions of the guard structure or by the photodiode pixels.Type: GrantFiled: April 20, 2001Date of Patent: January 13, 2004Assignee: Digirad CorporationInventor: Lars S. Carlson
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Patent number: 6670258Abstract: Ultra-low leakage current backside-illuminated semiconductor photodiode arrays are fabricated using a method of formation of a transparent, conducting bias electrode layer that avoids high-temperature processing of the substrate after the wafer has been gettered. As a consequence, the component of the reverse-bias leakage current associated with strain, crystallographic defects or impurities introduced during elevated temperature processing subsequent to gettering can be kept extremely low. An optically transparent, conductive bias electrode layer, serving as both an optical window and an ohmic backside equipotential contact surface for the photodiodes, is fabricated by etching through the polysilicon gettering layer and a portion of the thickness of heavily-doped crystalline silicon layer formed within, and near the back of, the substrate during the gettering process.Type: GrantFiled: April 20, 2001Date of Patent: December 30, 2003Assignee: Digirad CorporationInventors: Lars S. Carlson, Shulai Zhao, John Sheridan, Alan Mollet
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Patent number: 6630735Abstract: A semiconductor interconnection device having a semiconductor die, a plurality of epoxy bonds, and an array of insulating islands is disclosed. The semiconductor die has a plurality of conductive contacts. The plurality of epoxy bonds has a metallic substance such as silver. The epoxy bonds are configured to provide interconnection between the semiconductor die and an external structure. The plurality of epoxy bonds is selectively applied to the plurality of conductive contacts on the semiconductor die and corresponding conductive contacts on the external structure. The array of insulating islands is coupled to the plurality of conductive contacts. The islands are configured to prevent migration of the metallic substance from the plurality of epoxy bonds to the semiconductor die through the plurality of conductive contacts.Type: GrantFiled: April 7, 2000Date of Patent: October 7, 2003Assignee: Digirad CorporationInventors: Lars S. Carlson, Shulai Zhao
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Patent number: 6541763Abstract: A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector comprising a plurality of closely-packed detection modules. Each detection module comprises a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements. The circuit carrier includes channels for conditioning and processing the signals generated by corresponding detection elements and for preparing the processed signals for further processing by a signal processor. Each conditioning and processing channel stores the amplitudes of the detection element electrical pulses exceeding a predetermined threshold. The detection modules employ a fall-through circuit which automatically finds only those detection elements that have a stored pulse amplitude exceeding the threshold.Type: GrantFiled: April 15, 2002Date of Patent: April 1, 2003Assignee: Digirad CorporationInventors: Clinton L. Lingren, Stanley J. Friesenhahn, Jack F. Butler, F. Patrick Dory, William L. Ashburn, Frank L. Augustine, Boris Apotovsky
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Patent number: 6504178Abstract: A semiconductor imaging device is disclosed. The device includes a substrate having at least first and second surfaces opposing each other, and a circuit layer. The substrate is doped to exhibit a first conductivity type. The substrate includes a conducting layer, a region, and a plurality of doped regions. The conducting layer includes a first type dopants incorporated near the first surface. The region includes a heavily doped area within the substrate near the second surface. The plurality of doped regions includes a second type dopants formed on the second surface. The circuit layer is formed over the second surface to provide gate contacts to and readout circuits for the plurality of doped regions. The readout circuit provides readout of optical signals from pixels.Type: GrantFiled: April 5, 2001Date of Patent: January 7, 2003Assignee: Digirad CorporationInventors: Lars S. Carlson, Shulai Zhao, Richard Wilson
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Publication number: 20020185654Abstract: A passive mechanism suppresses injection, into any active guard regions interposed between the edge of a photodiode array chip and the outer photodiode pixels or into the outer pixels themselves, of minority carrier current generated in the physically disrupted region at the edge of the semiconductor die created by cleaving, sawing or otherwise separating the chip from the remainder of the wafer on which the die was fabricated. A thin metallic layer covers all or part of the edge region, thereby creating a Schottky barrier. This barrier generates a depletion region in the adjacent semiconductor material. The depletion region inherently creates an energy band distribution which preferentially accelerates minority carriers generated or near the metal-semiconductor interface towards the metal, thereby suppressing collection of these carriers by any active regions of the guard structure or by the photodiode pixels.Type: ApplicationFiled: August 7, 2002Publication date: December 12, 2002Applicant: Digirad Corporation, a Delaware corporationInventor: Lars S. Carlson
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Publication number: 20020148957Abstract: A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector comprising a plurality of closely-packed detection modules. Each detection module comprises a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements. The circuit carrier includes channels for conditioning and processing the signals generated by corresponding detection elements and for preparing the processed signals for further processing by a signal processor. Each conditioning and processing channel stores the amplitudes of the detection element electrical pulses exceeding a predetermined threshold. The detection modules employ a fall-through circuit which automatically finds only those detection elements that have a stored pulse amplitude exceeding the threshold.Type: ApplicationFiled: April 15, 2002Publication date: October 17, 2002Applicant: Digirad Corporation, a Delaware corporationInventors: Clinton L. Lingren, Stanley J. Friesenhahn, Jack F. Butler, F. Patrick Dory, William L. Ashburn, Frank L. Augustine, Boris Apotovsky
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Publication number: 20020079456Abstract: A radiation detector for detecting ionizing radiation. The detector includes a semiconductor having at least two sides. A bias electrode is formed on one side of the semiconductor. A signal electrode is formed on a side of the semiconductor and is used to detect the energy level of the ionizing radiation. A third electrode (the control electrode) is also formed on the semiconductor. The control electrode shares charges induced by the ionizing radiation with the signal electrode, shielding the signal electrode until the charge clouds are close to the signal electrode. The control electrode also alters the electric field within the semiconductor, such that the field guides the charge clouds toward the signal electrode when the clouds closely approach the signal electrode. As a result, signal loss due to trapped charge carriers (i.e., electrons or holes) is minimized, and low-energy tailing is virtually eliminated.Type: ApplicationFiled: November 13, 2001Publication date: June 27, 2002Applicant: Digirad Corporation, a California corporationInventors: Clinton L. Lingren, Jack F. Butler, Boris Apotovsky, Richard L. Conwell, F. Patrick Doty, Stanley J. Friesenhahn
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Publication number: 20010025928Abstract: A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector comprising a plurality of closely-packed detection modules. Each detection module comprises a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements. The circuit carrier includes channels for conditioning and processing the signals generated by corresponding detection elements and for preparing the processed signals for further processing by a signal processor. Each conditioning and processing channel stores the amplitudes of the detection element electrical pulses exceeding a predetermined threshold. The detection modules employ a fall-through circuit which automatically finds only those detection elements that have a stored pulse amplitude exceeding the threshold.Type: ApplicationFiled: January 30, 2001Publication date: October 4, 2001Applicant: Digirad Corporation, a Delaware corporationInventors: Clinton L. Lingren, Stanley J. Friesenhahn, Jack F. Butler, F. Patrick Doty, William L. Ashburn, Frank L. Augustine, Boris Apotovsky
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Patent number: 6194715Abstract: A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector including a plurality of closely-packed detection modules. Each detection module includes a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements. The circuit carrier includes channels for conditioning and processing the signals generated by corresponding detection elements and for preparing the processed signals for further processing by a signal processor. Each conditioning and processing channel stores the amplitudes of the detection element electrical pulses exceeding a predetermined threshold. The detection modules employ a fall-through circuit which automatically finds only those detection elements that have a stored pulse amplitude exceeding the threshold.Type: GrantFiled: April 5, 1999Date of Patent: February 27, 2001Assignee: Digirad CorporationInventors: Clinton L. Lingren, Stanley J. Friesenhahn, Jack F. Butler, F. Patrick Doty, William L. Ashburn, Frank L. Augustine, Boris Apotovsky
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Patent number: 6194726Abstract: A radiation detection device for gamma radiation is disclosed having an array of crystals optically positioned adjacent an optional collimator, the crystals emitting visible light upon illumination by the incident gamma radiation. An array of photodetectors is optically positioned adjacent the crystal array on the side of the crystal array opposite that of the collimator. A select photodetector in the photodetector array provides an output signal when the select photodetector is illuminated by the visible light. An integrated circuit having an input from the output signals of said array of photodetectors is used to process and output signals indicative of the intensity and position of the gamma radiation.Type: GrantFiled: September 22, 1998Date of Patent: February 27, 2001Assignee: Digirad CorporationInventors: Bo Pi, Timothy C. Collins, Richard L. Conwell
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Patent number: 6172362Abstract: A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector including a plurality of closely-packed detection modules. Each detection module includes a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements.Type: GrantFiled: April 5, 1999Date of Patent: January 9, 2001Assignee: Digirad CorporationInventors: Clinton L. Lingren, Stanley J. Friesenhahn, Jack F. Butler, F. Patrick Doty, William L. Ashburn, Frank L. Augustine, Boris Apotovsky