Abstract: A radiation detector includes a top gate thin film transistor (TFT) including a source electrode, a drain electrode, a gate electrode, a TFT dielectric layer, a TFT semiconductive layer, and a TFT intrinsic amorphous silicon (a-Si) layer. The radiation detector also includes a capacitor including a first electrode, a second electrode substantially coplanar with the gate electrode, and a capacitor dielectric, the capacitor dielectric including a capacitor dielectric layer substantially coplanar with the TFT dielectric layer, a capacitor semiconductive layer substantially coplanar with the TFT semiconductive layer, and a capacitor a-Si layer substantially coplanar with the TFT a-Si layer.

Abstract: In one aspect of the invention a method for processing a fluoroscopic image is provided. The method includes scanning an object with an imaging system including at least one radiation source and at least one detector array, acquiring a plurality of dark images to generate a baseline image, acquiring a plurality of lag images subsequent to the baseline image, determining a plurality of parameters of a power law using at least one lag image and at least one baseline image, and performing a log-log extrapolation of the power law including the determined parameters.

Abstract: An imaging array of photodiodes on a chip cut from a semiconductor wafer includes a guard diode at each cut edge to reduce leakage current from the cut edges when the imaging array is in use. The photodiodes and guard diode may be fabricated from the same materials during the same process step. Electrical contacts coupled to the imaging array provide a mechanism for applying a reverse electrical bias to the photodiodes and guard region with respect to the wafer.

Abstract: In an imager having an array of light-sensitive elements and employing striped common electrodes, exposed edges of preimidized polyimide layers above the light-sensitive imaging elements are sealed with the material of the common electrode (e.g., indium tin oxide). Similarly, exposed preimidized polyimide edges in electrical contacts for the array and bridge members electrically coupling adjacent light-sensitive imaging elements are also sealed with the material of the common electrode.

Abstract: RD-25953-17-A method of fabricating an imager array having a plurality of pixels is provided in which each pixel is made up of a photodiode and a corresponding thin film transistor (TFT) switching device, the method including the steps of depositing materials to form the photodiode island and to form a TFT body over a gate electrode, then depositing a layer of source/drain metal over the silicon layers of the TFT body, and over a common dielectric layer, removing sections of the source/drain metal layer to expose a portion of the silicon layers of the TFT body, but leaving regions of sacrificial source/drain metal over the photodiode islands, and forming a back channel in the TFT body by a back channel etch step. The method further includes then removing the sacrificial regions of source/drain metal from above the photodiode islands, and depositing a passivation layer over the entire exposed surface of the array.

Abstract: In an imager having an array of light-sensitive elements and employing striped common electrodes, exposed edges of preimidized polyimide layers above the light-sensitive imaging elements are sealed with the material of the common electrode (e.g., indium tin oxide). Similarly, exposed preimidized polyimide edges in electrical contacts for the array and bridge members electrically coupling adjacent light-sensitive imaging elements are also sealed with the material of the common electrode.

Abstract: RD-25953-17-A method of fabricating an imager array having a plurality of pixels is provided in which each pixel is made up of a photodiode and a corresponding thin film transistor (TFT) switching device, the method including the steps of depositing materials to form the photodiode island and to form a TFT body over a gate electrode, then depositing a layer of source/drain metal over the silicon layers of the TFT body, and over a common dielectric layer, removing sections of the source/drain metal layer to expose a portion of the silicon layers of the TFT body, but leaving regions of sacrificial source/drain metal over the photodiode islands, and forming a back channel in the TFT body by a back channel etch step. The method further includes then removing the sacrificial regions of source/drain metal from above the photodiode islands, and depositing a passivation layer over the entire exposed surface of the array.

Abstract: A method and system for an automatic exposure control (AEC) arrangement for a matrix-addressed imaging panel having an array of sensors including use of localized regions of the imaging panel exhibiting capacitive coupling. In one embodiment, the matrix-addressed imaging panel includes one or more AEC electrode receptive field regions that provide a signal representative of exposure specific, respective AEC electrode receptive field regions. Additionally, in another embodiment, the imaging array includes data line signal monitoring regions in which capacitive coupling between electrodes in radiation sensors adjacent to the data line are read and processed to provide and AEC signal. In another embodiment, the imaging array includes both AEC electrode filed receptive regions and data line signal monitoring regions that are coupled to an AEC controller for control of the radiation source for the imaging array.

Abstract: An imaging array of photodiodes on a chip cut from a semiconductor wafer includes a guard diode at each cut edge to reduce leakage current from the cut edges when the imaging array is in use. The photodiodes and guard diode may be fabricated from the same materials during the same process step. Electrical contacts coupled to the imaging array provide a mechanism for applying a reverse electrical bias to the photodiodes and guard region with respect to the wafer.

Abstract: A light block material disposed over the photosensitive region of a switching device (e.g., TFT) of a radiation imager is disclosed. The light block material prevents optical photons emitted from a scintillator from passing into the switching device and being absorbed. Cross-talk and noise in the imager are thereby reduced. Also, non-linear pixel response and spurious signals passing to readout electronics are avoided. Optionally, opaque caps comprising the same light block material may be included in the imager structure. The caps cover contact vias filled with a common electrode and located in the contact finger region of the imager. The integrity of the filled vias is thereby maintained during subsequent processing. Also disclosed is a radiation imager containing these structures.

Abstract: A fiber optic scintillator includes, for example, a first plurality of radiation absorbing elements comprising a scintillating material for converting radiation into light and a second plurality of radiation absorbing elements interspersed among the first plurality of radiation absorbing elements. The first plurality of radiation absorbing elements has a first radiation absorption efficiency. The second plurality of radiation absorbing elements has a second radiation absorption efficiency and an effective atomic number greater than about 50. The second radiation absorption efficiency is greater than said first radiation absorption efficiency. A scintillator forming method provides a bundle of the second plurality of radiation absorbing elements interspersed among the first plurality of radiation absorbing elements by drawing the bundle, The drawn bundle is cut into a plurality of sections.

Abstract: A method of forming a contact for a photosensitive element of a photosensitive imager including a common electrode separated from a bottom contact by intervening layers of an SiOx transistor passivation layer over the bottom contact and an SiNx diode passivation layer over the transistor passivation layer. Controlled etching through the passivation layers exposes but does not damage the thin film transistor passivation layer extending in regions beyond the common electrode, and also improves adherence of a protective gasket in such regions. The contact pad formed in this process has a layer of diode passivation material and a layer of transistor passivation material disposed between the upper common electrode material layer and the underlying source and drain electrode material layer, with a via provided having smooth and sloped sidewalls over which the common electrode material extends to provide electrical contact between the common electrode material layer and the source and drain electrode material layer.

Abstract: A radiation imager includes a photosensor array that is coupled to a scintillator so as to detect optical photons generated when incident radiation is absorbed in the scintillator. The imager includes an optical crosstalk attenuator that is optically coupled to a first surface of the scintillator (that is, the surface opposite the photosensor). The optical crosstalk attenuator includes an optical absorption material that is disposed so as to inhibit reflection of optical photons incident on the scintillator first surface back into the scintillator along selected crosstalk reflection paths. The crosstalk reflection paths are those paths oriented such that optical photons passing along such paths would be incident upon photosensor array pixels that are outside of a selected focal area corresponding to the absorption point in the scintillator.

Abstract: A method of forming a contact for a photosensitive element of a photosensitive imager including a common electrode separated from a bottom contact by intervening layers of an SiOx transistor passivation layer over the bottom contact and an SiNx diode passivation layer over the transistor passivation layer. Controlled etching through the passivation layers exposes but does not damage the thin film transistor passivation layer extending in regions beyond the common electrode, and also improves adherence of a protective gasket in such regions. The contact pad formed in this process has a layer of diode passivation material and a layer of transistor passivation material disposed between the upper common electrode material layer and the underlying source and drain electrode material layer, with a via provided having smooth and sloped sidewalls over which the common electrode material extends to provide electrical contact between the common electrode material layer and the source and drain electrode material layer.

Abstract: Contact pads for providing external electrical connection to components on a radiation imager having a photosensor array include a body of the material utilized for fabrication of the photosensors with an indium tin oxide (ITO) top layer disposed over the photosensor material to provide a contact region. A metal contact surface can also be disposed over the ITO. A barrier dielectric material is further disposed over portions of the contact pad.

Abstract: A radiation imager having a plurality of photosensitive elements has a two-tier passivation layer disposed between the top patterned common electrode contact layer and respective photosensor islands. The top passivation layer is a polymer bridge member disposed between adjacent photodiodes so as to isolate defects such as moisture-induced leakage in any bridge island layer to the two adjacent photodiodes spanned by the bridge island.

Abstract: An imager array includes a substrate with a plurality of superimposed layers of electrically conductive and active components. Sets of scan and data lines are electrically insulated from one another and also from a common electrode and active array components by dielectric material. Protection of the active components against static charge potential includes resistive means between the common electrode and a ground ring conductor around the array elements and in particular a thin film transistor circuit with a parallel pair of opposite polarity diode connected field effect transistors to safely drain the static charge during subsequent fabrication, test and standby period of the imager, while remaining in circuit during imager operation.

Abstract: A flat panel radiation imaging device that exhibits reduced capacitive coupling between pixel photodiode electrodes and readout data lines, and thus exhibits reduced phantom images and image artifacts in operation, includes a low-capacitive-coupling common electrode disposed over a pixel array of photosensors, switching transistors, and address lines that are arranged in an imaging array pattern of rows and columns. The low-capacitive coupling common electrode includes a plurality of common electrode column segments oriented along the same axis as the data lines in the array, with each of the common electrode column segments corresponding to a respective column of photosensors in the imaging array pattern.