X-scan Imaging Corporation

Scan Vision Limited

Peripheral Imaging Corporation

Hsin-Fu Tseng

Linbo Yang

Weng-Lyang Wang

Shizu Li

Chinlee Wang

Pheng Tan

Satoru C Tanaka

Nguyen Phuoc Luu

Lin-Bo Yang

A dual or multi-energy range x-ray image sensor is implemented as side-by-side pixel arrays on a planar and monolithic semiconductor substrate as part of an x-ray object detector. Each pixel array in this side-by-side monolithic arrangement is designed to be responsive to a particular x-ray energy range or spectrum (i.e. a high-energy (HE) range or a low-energy (LE) range) to provide high object sensitivity and material discrimination capabilities. The side-by-side monolithic construction of pixel arrays improves alignment and spacing precision for improved image alignment among different arrays specialized in detecting different energy levels and signatures. Furthermore, integrated signal processing circuitry, placed on a radiation-shielded periphery of the pixel arrays, enables improved detection performance with enhanced noise reduction and/or sensitivity. This novel configuration is scalable by increasing the number of side-by-side and monolithically-placed pixel arrays, each of which is specialized in detecting a specific energy range from a scanned object.

Integrated side-by-side pixel-array sensor-based multi-energy range x-ray detector

A dual/multi-energy x-ray image sensor with stacked two-dimensional pixel arrays. Each pixel in one pixel array has a corresponding 'overlaid' pixel in the other pixel array. The pixel arrays are stacked parallel and aligned so that they are nominally normal to the x-ray path, and so that a straight path taken by an x-ray photon from the x-ray source to a pixel in one pixel array will also nominally intersect the corresponding pixel in the other pixel array(s). The energy image sensor provides an x-ray scanning detector system, which has increased signal levels and signal-to-noise ratios over dual- or multi-energy detectors using linear diode arrays, specifically when the pixel arrays are TDI pixel arrays that offer higher sensitivities in high-speed line-scan applications. Signal processing circuitry is placed on a periphery of the pixel arrays and shielded. Dual-to-multiple energy applications can be accomplished by increasing the number of stacked pixel arrays.

Dual/multiple-energy x-ray sensor with separation between pixels and active circuitry

An X-ray line-scan camera utilizes an image transferring means to alter the optical path and thus eliminates the X-ray radiation damage on the electrical components of the camera system. The camera comprises a layer of scintillating material, a fiber optic face plate (FOFP) block, and an array of image sensors. One face of the FOFP block is bonded to the surface of the image sensors. The layer of scintillating material is placed on other face of the FOFP block and used to convert an impinging X-ray beam into visible light. The FOFP block is used to transfer the visible light from the scintillating layer onto the image sensor array, which in turn converts the visible light into electrical video signals. The FOFP block has a rotation angle of 32 to 40 degree relative to the impinging X-ray beam to prevent direct impingement of the X-ray beam onto the image sensors.

Linear X-ray detector using fiber optic face plate to alter optical path

A radiation damage resistant linear X-ray detector array system based on a unique buttable monolithic image sensor design and precision chip-on-board assembly technology includes at least one of the detector chips. Multiple chips of the image sensor may be butted end-to-end on a common printed circuit board to accommodate larger detection systems. A layer of scintillating material, such as GdOS:Tb (GOS), CsI(Tl), or CdWO, is placed on the image sensor to convert the impinging X-ray energies into visible light which can be detected efficiently by the image sensor array. A protective metal shield is fastened to the substrate to protect the sensitive circuits of the image sensor from X-ray radiation damage. A proper separation of sensitive circuits from the photodiode array on the sensor chip, coupled with precision registration of the sensor chips on the substrate, allows easy installation of the protective metal shield.

Linear X-ray detector with monolithic detector chip including both photodiode array and peripheral circuits spaced apart

A radiation damage resistant linear X-ray detector array system based on a unique focusing principle reduces or eliminates the X-ray radiation damage on the electrical components of the detector system. The system includes a layer of scintillating material, a rod lens array, and an array of image sensors. The layer of scintillating material, such as GdOS:Tb (GOS or GADOX), CsI(TI), or CdWO, is placed on an image plane and used to convert the impinging X-ray energies into visible light which can be detected efficiently by the image sensor array. The rod lens array is used to focus the visible light after the X-ray flux has been converted. The photon energy of the visible light is collected with a scanning image sensor array that converts the photon energy proportionally into electrical video signals and enables the signals to be processed using standard signal and image processing software and equipment.

Linear X-ray detector using rod lens array

A dynamic threshold two-level A/D converter, also termed a tracking digitizer circuit. The module circuitry includes a comparator circuit and a tracking low-pass filter circuit. The dynamic thresholding module takes the output signals from a CIS module and develops a tracking (variable) background signal. The tracking background signal is then compared to the output signals from the CIS in a comparator. The comparator outputs a two-level (binary) output digital signal. The circuit is designed to be used in conjunction with a scanning device, particularly a CIS system. The circuit can be used in a wide variety of applications that require pre-processed digitized video signals. The dynamic thresholding module's circuitry can be implemented quite simply. Moreover, the circuit provides a very low cost and a low parts density module that can easily be incorporated with existing CIS modules without substantially increasing the size of the CIS module or the cost to manufacture the unit. The circuit requires roughly half the space required by existing digital circuits that accomplish similar ends.

Dynamic thresholding module

A Contact Image Sensor (CIS) system utilizing a phototransistor sensing element that consists of a mechanism to pre-charge or inject a 'background charge' into the storage node and allow the charge to reset through the same output base-to-emitter junction. This pre-charge and reset process removes the residual image and replenishes the charge lost by the base-to-emitter sub-threshold leakage current. Furthermore, the reset of the injected charge through the same output base-to-emitter junction automatically sets the phototransistor to an initial dark level, which is at the start of a linear region of the response versus illumination curve, and thus substantially improves the photo-response linearity.

Charge storage image scanner having equalizing pre-charge and reset

A contact image sensing system that eliminates the use of npn phototransistors. The device comprises a plurality of sensing elements, a like number of dummy sensing elements, control and drive clocks, a digital scanning shift register, and a differential amplifier. The device operates by sequentially reading the voltage output of the sensors, then comparing that output with the output of the dummy sensors so that any noise or offset in the signal can be cancelled by a differential amplifier.

Contact image sensor utilizing differential voltage pickoff

A color-reproducing contact image sensing (CORCIS) system that eliminates the use of multiple arrays of photodetectors with separate color filters and which permits the use of any of various signal-processing improvements such as voltage pickoff, transducer gain and correlated double sample and hold processing. The device operates by sequentially illuminating the colored object to be reproduced by primary color illumination means, with each illumination transferring in parallel the appropriate color response to a readout register for sequential readout. The sample and hold, and the parallel transfer operation, allow the CORCIS system to be able to read out signal while the detector array is integrating the next color signal, thus improving the sensitivity.

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Los Altos, CA, United States of America

Hsin-Fu Tseng