Patent Description:
Portable digital radiographic detectors have been widely deployed to improve diagnostic radiographic imaging productivity, image quality and ease of use. In particular, mobile or bedside radiographic imaging is conducted in locations such as intensive care units so that the patient does not need to be transported from their critical care environment. This type of imaging procedure is best served by a portable detector that is light weight and durable to improve ease of use and reliability.

Current digital radiographic detectors typically include an amorphous silicon TFT/photo diode image sensor array that is fabricated on glass using semiconductor processes that are similar to those used for flat panel displays. A scintillator is combined with the image sensor array along with required electronics for signal readout and processing onto an internal core plate which is contained within a durable housing to create the portable DR detector.

<FIG> is a perspective view of a digital radiographic (DR) imaging system <NUM> that may include a generally curved or planar DR detector <NUM> (shown in a planar embodiment and without a housing for clarity of description), an x-ray source <NUM> configured to generate radiographic energy (x-ray radiation), and a digital monitor, or electronic display, <NUM> configured to display images captured by the DR detector <NUM>, according to one embodiment. The DR detector <NUM> may include a two dimensional array <NUM> of detector cells <NUM> (photosensors), arranged in electronically addressable rows and columns. The DR detector <NUM> may be positioned to receive x-rays <NUM> passing through a subject <NUM> during a radiographic energy exposure, or radiographic energy pulse, emitted by the x-ray source <NUM>. As shown in <FIG>, the radiographic imaging system <NUM> may use an x-ray source <NUM> that emits collimated x-rays <NUM>, e.g. an x-ray beam, selectively aimed at and passing through a preselected region <NUM> of the subject <NUM>. The x-ray beam <NUM> may be attenuated by varying degrees along its plurality of rays according to the internal structure of the subject <NUM>, which attenuated rays are detected by the array <NUM> of photosensitive detector cells <NUM>. The curved or planar DR detector <NUM> is positioned, as much as possible, in a perpendicular relation to a substantially central ray <NUM> of the plurality of rays <NUM> emitted by the x-ray source <NUM>. In a curved array embodiment, the source <NUM> may be centrally positioned such that a larger percentage, or all, of the photosensitive detector cells are positioned perpendicular to incoming x-rays from the centrally positioned source <NUM>. The array <NUM> of individual photosensitive cells (pixels) <NUM> may be electronically addressed (scanned) by their position according to column and row. As used herein, the terms "column" and "row" refer to the vertical and horizontal arrangement of the photosensor cells <NUM> and, for clarity of description, it will be assumed that the rows extend horizontally and the columns extend vertically. However, the orientation of the columns and rows is arbitrary and does not limit the scope of any embodiments disclosed herein. Furthermore, the term "subject" may be illustrated as a human patient in the description of <FIG>, however, a subject of a DR imaging system, as the term is used herein, may be a human, an animal, an inanimate object, or a portion thereof.

In one exemplary embodiment, the rows of photosensitive cells <NUM> may be scanned one or more at a time by electronic scanning circuit <NUM> so that the exposure data from the array <NUM> may be transmitted to electronic read-out circuit <NUM>. Each photosensitive cell <NUM> may independently store a charge proportional to an intensity, or energy level, of the attenuated radiographic radiation, or x-rays, received and absorbed in the cell. Thus, each photosensitive cell, when read-out, provides information defining a pixel of a radiographic image <NUM>, e.g. a brightness level or an amount of energy absorbed by the pixel, that may be digitally decoded by image processing electronics <NUM> and transmitted to be displayed by the digital monitor <NUM> for viewing by a user. An electronic bias circuit <NUM> is electrically connected to the two-dimensional detector array <NUM> to provide a bias voltage to each of the photosensitive cells <NUM>.

Each of the bias circuit <NUM>, the scanning circuit <NUM>, and the read-out circuit <NUM>, may communicate with an acquisition control and image processing unit <NUM> over a connected cable <NUM> (wired), or the DR detector <NUM> and the acquisition control and image processing unit <NUM> may be equipped with a wireless transmitter and receiver to transmit radiographic image data wirelessly <NUM> to the acquisition control and image processing unit <NUM>. The acquisition control and image processing unit <NUM> may include a processor and electronic memory (not shown) to control operations of the DR detector <NUM> as described herein, including control of circuits <NUM>, <NUM>, and <NUM>, for example, by use of programmed instructions, and to store and process image data. The acquisition control and image processing unit <NUM> may also be used to control activation of the x-ray source <NUM> during a radiographic exposure, controlling an x-ray tube electric current magnitude, and thus the fluence of x-rays in x-ray beam <NUM>, and/or the x-ray tube voltage, and thus the energy level of the x-rays in x-ray beam <NUM>. A portion or all of the acquisition control and image processing unit <NUM> functions may reside in the detector <NUM> in an on-board processing system <NUM> which may include a processor and electronic memory to control operations of the DR detector <NUM> as described herein, including control of circuits <NUM>, <NUM>, and <NUM>, by use of programmed instructions, and to store and process image data similar to the functions of standalone acquisition control and image processing system <NUM>. The image processing system may perform image acquisition and image disposition functions as described herein. The image processing system <NUM> may control image transmission and image processing and image correction on board the detector <NUM> based on instructions or other commands transmitted from the acquisition control and image processing unit <NUM>, and transmit corrected digital image data therefrom. Alternatively, acquisition control and image processing unit <NUM> may receive raw image data from the detector <NUM> and process the image data and store it, or it may store raw unprocessed image data in local memory, or in remotely accessible memory.

With regard to a direct detection embodiment of DR detector <NUM>, the photosensitive cells <NUM> may each include a sensing element sensitive to x-rays, i.e. it absorbs x-rays and generates an amount of charge carriers in proportion to a magnitude of the absorbed x-ray energy. A switching element may be configured to be selectively activated to read out the charge level of a corresponding x-ray sensing element. With regard to an indirect detection embodiment of DR detector <NUM>, photosensitive cells <NUM> may each include a sensing element sensitive to light rays in the visible spectrum, i.e. it absorbs light rays and generates an amount of charge carriers in proportion to a magnitude of the absorbed light energy, and a switching element that is selectively activated to read the charge level of the corresponding sensing element. A scintillator, or wavelength converter, may be disposed over the light sensitive sensing elements to convert incident x-ray radiographic energy to visible light energy. Thus, in the embodiments disclosed herein, it should be noted that the DR detector <NUM> (or DR detector <NUM> in <FIG> or DR detector <NUM> in <FIG>) may include an indirect or direct type of DR detector.

Examples of sensing elements used in sensing array <NUM> include various types of photoelectric conversion devices (e.g., photosensors) such as photodiodes (P-N or PIN diodes), photo-capacitors (MIS), photo-transistors or photoconductors. Examples of switching elements used for signal read-out include a-Si TFTs, oxide TFTs, MOS transistors, bipolar transistors and other p-n junction components.

<FIG> is a schematic diagram <NUM> of a portion of a two-dimensional array <NUM> for a DR detector <NUM>. The array of photosensor cells <NUM>, whose operation may be consistent with the photosensor array <NUM> described above, may include a number of hydrogenated amorphous silicon (a-Si:H) n-i-p photodiodes <NUM> and thin film transistors (TFTs) <NUM> formed as field effect transistors (FETs) each having gate (G), source (S), and drain (D) terminals. In embodiments of DR detector <NUM> disclosed herein, such as a multilayer DR detector (<NUM> of <FIG>), the two-dimensional array of photosensor cells <NUM> may be formed in a device layer that abuts adjacent layers of the DR detector structure, which adjacent layers may include a rigid glass layer or a flexible polyimide layer or a layer including carbon fiber without any adjacent rigid layers. A plurality of gate driver circuits <NUM> may be electrically connected to a plurality of gate lines <NUM> which control a voltage applied to the gates of TFTs <NUM>, a plurality of readout circuits <NUM> may be electrically connected to data lines <NUM>, and a plurality of bias lines <NUM> may be electrically connected to a bias line bus or a variable bias reference voltage line <NUM> which controls a voltage applied to the photodiodes <NUM>. Charge amplifiers <NUM> may be electrically connected to the data lines <NUM> to receive signals therefrom. Outputs from the charge amplifiers <NUM> may be electrically connected to a multiplexer <NUM>, such as an analog multiplexer, then to an analog-to-digital converter (ADC) <NUM>, or they may be directly connected to the ADC, to stream out the digital radiographic image data at desired rates. In one embodiment, the schematic diagram of <FIG> may represent a portion of a DR detector <NUM> such as an a-Si:H based indirect flat panel, curved panel, or flexible panel imager.

Incident x-rays, or x-ray photons, <NUM> are converted to optical photons, or light rays, by a scintillator, which light rays are subsequently converted to electron-hole pairs, or charges, upon impacting the a-Si:H n-i-p photodiodes <NUM>. In one embodiment, an exemplary detector cell <NUM>, which may be equivalently referred to herein as a pixel, may include a photodiode <NUM> having its anode electrically connected to a bias line <NUM> and its cathode electrically connected to the drain (D) of TFT <NUM>. The bias reference voltage line <NUM> can control a bias voltage of the photodiodes <NUM> at each of the detector cells <NUM>. The charge capacity of each of the photodiodes <NUM> is a function of its bias voltage and its capacitance. In general, a reverse bias voltage, e.g. a negative voltage, may be applied to the bias lines <NUM> to create an electric field (and hence a depletion region) across the pn junction of each of the photodiodes <NUM> to enhance its collection efficiency for the charges generated by incident light rays. The image signal represented by the array of photosensor cells <NUM> may be integrated by the photodiodes while their associated TFTs <NUM> are held in a non-conducting (off) state, for example, by maintaining the gate lines <NUM> at a negative voltage via the gate driver circuits <NUM>. The photosensor cell array <NUM> may be read out by sequentially switching rows of the TFTs <NUM> to a conducting (on) state by means of the gate driver circuits <NUM>. When a row of the pixels <NUM> is switched to a conducting state, for example by applying a positive voltage to the corresponding gate line <NUM>, collected charge from the photodiode in those pixels may be transferred along data lines <NUM> and integrated by the external charge amplifier circuits <NUM>. The row may then be switched back to a non-conducting state, and the process is repeated for each row until the entire array of photosensor cells <NUM> has been read out. The integrated signal outputs are transferred from the external charge amplifiers <NUM> to an analog-to-digital converter (ADC) <NUM> using a parallel-to-serial converter, such as multiplexer <NUM>, which together comprise read-out circuit <NUM>.

This digital image information may be subsequently processed by image processing system <NUM> to yield a digital image which may then be digitally stored and immediately displayed on monitor <NUM>, or it may be displayed at a later time by accessing the digital electronic memory containing the stored image. The flat panel DR detector <NUM> having an imaging array as described with reference to <FIG> is capable of both single-shot (e.g., static, radiographic) and continuous (e.g., fluoroscopic) image acquisition.

<FIG> shows a perspective view of an exemplary prior art generally rectangular, planar, portable wireless DR detector <NUM> according to an embodiment of DR detector <NUM> disclosed herein. The DR detector <NUM> may include a flexible substrate to allow the DR detector to capture radiographic images in a curved orientation. The flexible substrate may be fabricated in a permanent curved orientation, or it may remain flexible throughout its life to provide an adjustable curvature in two or three dimensions, as desired. The DR detector <NUM> may include a similarly flexible housing portion <NUM> that surrounds a multilayer structure, or core, comprising a flexible photosensor array portion <NUM> of the DR detector <NUM>. The housing portion <NUM> of the DR detector <NUM> may include a continuous, rigid or flexible, x-ray opaque material or, as used synonymously herein a radio-opaque material, surrounding an interior volume of the DR detector <NUM>. The housing portion <NUM> may include four flexible edges <NUM>, extending between the top side <NUM> and the bottom side <NUM>, and arranged substantially orthogonally in relation to the top and bottom sides <NUM>, <NUM>. The bottom side <NUM> may be continuous with the four edges and disposed opposite the top side <NUM> of the DR detector <NUM>. The top side <NUM> comprises a top cover <NUM> attached to the housing portion <NUM> which, together with the housing portion <NUM>, substantially encloses the core in the interior volume of the DR detector <NUM>. The top cover <NUM> may be attached to the housing <NUM> to form a seal therebetween, and be made of a material that passes x-rays <NUM> without significant attenuation thereof, i.e., an x-ray transmissive material or, as used synonymously herein, a radiolucent material, such as a carbon fiber, carbon fiber embedded plastic, polymeric, elastomeric and other plastic based material.

With reference to <FIG>, there is illustrated in schematic form an exemplary cross-section view along section <NUM>-<NUM> of the exemplary embodiment of the DR detector <NUM> (<FIG>). For spatial reference purposes, one major surface, or side, of the DR detector <NUM> may be referred to as the top side <NUM> and a second major surface, or side, of the DR detector <NUM> may be referred to as the bottom side <NUM>, as used herein. The core layers, or sheets, may be disposed within the interior volume <NUM> enclosed by the housing <NUM> and top cover <NUM> and may include a flexible curved or planar scintillator layer <NUM> over a curved or planar the two-dimensional imaging sensor array <NUM> shown schematically as the device layer <NUM>. The scintillator layer <NUM> may be directly under (e.g., directly connected to) the substantially planar top cover <NUM>, and the imaging array <NUM> may be directly under the scintillator <NUM>. Alternatively, a flexible layer <NUM> may be positioned between the scintillator layer <NUM> and the top cover <NUM> as part of the core layered structure to allow adjustable curvature of the core layered structure and/or to provide shock absorption. The flexible layer <NUM> may be selected to provide an amount of flexible support for both the top cover <NUM> and the scintillator <NUM>, and may comprise a foam rubber type of material. The layers just described comprising the multilayer core structure each may generally be formed in a rectangular shape and defined by edges arranged orthogonally and disposed in parallel with an interior side of the edges <NUM> of the housing <NUM>, as described in reference to <FIG>.

A substrate layer <NUM> may be disposed under the imaging array <NUM>, such as a rigid glass layer, in one embodiment, or flexible substrate comprising polyimide or carbon fiber upon which the array of photosensors <NUM> may be formed to allow adjustable curvature of the array, and may comprise another layer of the core layered structure. Under the substrate layer <NUM> a radio-opaque shield layer <NUM>, such as lead, may be used as an x-ray blocking layer to help prevent scattering of x-rays passing through the substrate layer <NUM> as well as to block x-rays reflected from other surfaces in the interior volume <NUM>. Readout electronics, including the scanning circuit <NUM>, the read-out circuit <NUM>, the bias circuit <NUM>, and processing system <NUM> (all shown in <FIG>) may be formed adjacent the imaging array <NUM> or, as shown, may be disposed below frame support member <NUM> in the form of integrated circuits (ICs) electrically connected to printed circuit boards (PCBs) <NUM>, <NUM>. The imaging array <NUM> may be electrically connected to the readout electronics <NUM> (ICs) over a flexible connector <NUM> which may comprise a plurality of flexible, sealed conductors known as chip-on-film (CoF) connectors.

X-ray flux may pass through the radiolucent top panel cover <NUM>, in the direction represented by an exemplary x-ray beam <NUM>, and impinge upon scintillator <NUM> where stimulation by the high-energy x-rays <NUM>, or photons, causes the scintillator <NUM> to emit lower energy photons as visible light rays which are then received in the photosensors of imaging array <NUM>. The frame support member <NUM> may connect the core layered structure to the housing <NUM> and may further operate as a shock absorber by disposing elastic pads (not shown) between the frame support beams <NUM> and the housing <NUM>. Fasteners <NUM> may be used to attach the top cover <NUM> to the housing <NUM> and create a seal therebetween in the region <NUM> where they come into contact. In one embodiment, an external bumper <NUM> may be attached along the edges <NUM> of the DR detector <NUM> to provide additional shock-absorption.

Recently, processes have been developed that enable fabrication of the image sensor array onto durable thin substrates such as polyimide. This highly durable substrate enables the use of alternative housing components that are lighter in weight since the need for glass protection is reduced.

<CIT> discloses a portable radiographic detector with a casing having a front face including a top plate and a rear face fitted into the front face such that second sides of the rear face are disposed inside of first sides of the front face. Water-resistant members are disposed in corner portions that are formed in the front face. The second sides have ridges for pressing and elastically deforming the water-resistant members toward the top plate.

<CIT> discloses an intraoral sensor with a sensor panel, a circuit unit, a memory, a battery, a casing, a first connector, and a power terminal. A docking station receives the sensor and provides a second connector connected to the first connector to receive the image signal stored in the memory.

<CIT> discloses a digital X-ray detector with an X-ray detection array for detecting an X-ray image when a subject is irradiated. A board supports a bottom of the array, a case accommodates the array and the board. A plurality of insertion portions is formed on four sidewalls thereof, and shock abortion members are installed for each of the insertion portions and have a head resting on an outer wall of the case.

<CIT> discloses a curved radiographic detector with electromagnetic radiation sensitive elements disposed in a two-dimensional array. A curved housing encloses the array of radiation sensitive elements and includes a layer of aligned carbon nanotubes on a surface thereof.

<CIT> discloses a radiographic detector with external force action mechanisms for applying external force to peripheral sections of a radiation conversion panel, for applying external force while being laminated on the panel, or for pressing the panel against the inner wall of another panel.

<CIT> discloses a portable radiographic detector having a housing with a rectangular tube-shaped body that has a radiation entrance plane and multiple radiation detection elements. Shock absorbing material is provided between the inner surface of the plane and a sensor panel arranged in a 2D form. A plate-shaped sliding unit is interposed between the shock absorbing material and the inner surface of the plane.

In accordance with the present invention, a digital radiographic detector and a method as set forth in claims <NUM> and <NUM>, respectively, is provided. Further embodiments of the invention are inter alia disclosed in the dependent claims. A digital radiographic detector includes a planar multilayer core having a two-dimensional array of photo-sensitive cells. An enclosure having only one open side with upper and lower halves is joined together using a three-sided bumper configured to provide impact absorption for sides of the enclosure, or housing. A thermally conductive end cap covers the only one open side of the enclosure.

In one embodiment, a DR detector includes a planar multilayer core comprising a two-dimensional array of photo-sensitive cells. A rectangular shaped housing made from upper and lower shells joined together surround the multilayer core and leave only one open side along the width of the DR detector. An end cap covers the only one open side of the enclosure.

In one embodiment, a carbon fiber housing in the form of an upper and lower half are joined by a seam around the perimeter covered and secured together by an interlocking bumper. The upper half is as thick or thicker than the bottom half, which may be achieved by a single upper half part or by laminating two or more parts together. A thermally conductive end cap is mounted on an open fourth side of the enclosure to complete the enclosure and dissipate heat. Together, the enclosure forms a protective, fluid resistant, structural encasement for the detector panel assembly.

In one embodiment, the detector panel assembly is laminated to the inner surface of the upper half for support. This laminate configuration is stiffer than the individual components. The rigidity may also be further enhanced by adding lightweight core materials between the upper half and sensor panel assembly to increase separation distance and/or stiff materials below the sensor panel assembly for protection. All or portions of the sensor panel electronics may be restrained to the laminate structure. Beneath the laminate structure, a high strength, lightweight material such as foam is used to support loads applied to the detector. In areas cutout for electronics, stiff materials are integrated with the lightweight material to redirect, i.e. bridge, loads away from the electronics to the surrounding area. The sides and lower half of the enclosure, constructed of thinner material, act as a shock absorbing element, further enhancing durability.

It is an object of the invention to provide a light weight, durable DR housing and core plate assembly that takes advantage of the benefits provided by a non-glass substrate image sensor panel. Additionally, a method of providing electro-magnetic compatibility and ease of assembly is included.

This brief description of the invention is intended only to provide a brief overview of subject matter disclosed herein according to one or more illustrative embodiments, and does not serve to define or limit the scope of the invention, which is defined only by the appended claims. This brief description is provided to introduce an illustrative selection of concepts in a simplified form that are further described below in the detailed description. This brief description is not intended to identify key features or essential features of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.

So that the manner in which the features of the invention can be understood, a detailed description of the invention may be had by reference to certain embodiments, some of which are illustrated in the accompanying drawings. It is to be noted, however, that the drawings illustrate only certain embodiments of this invention and are therefore not to be considered limiting of its scope, for the scope of the invention encompasses other equally effective embodiments. The drawings are not necessarily to scale, emphasis generally being placed upon illustrating the features of certain embodiments of the invention. In the drawings, like numerals are used to indicate like parts throughout the various views. Thus, for further understanding of the invention, reference can be made to the following detailed description, read in connection with the drawings in which:.

This application claims priority to <CIT>, and entitled RADIOGRAPHIC DETECTOR.

Referring to <FIG>, an exploded view of components of an inventive assembly for a DR detector <NUM> includes an upper shell <NUM> secured to a lower shell <NUM> using a U-shaped, or three-sided, bumper <NUM>. The bumper <NUM> engages flanged edges (<FIG>) of the upper shell <NUM> and the lower shell <NUM> to secure them together. Adhesive is also used between the flanged edges and on an inside surface of the bumper <NUM>. When joined together, the upper shell <NUM> and the lower shell <NUM> leave an opening along a width of the shells because upper and lower shell edges 501a, 502a, respectively, are not folded over and so do not contact each other. The upper and lower shells <NUM>, <NUM>, enclose a multilayer core <NUM> which includes a two dimensional array of photosensors, a scintillator, a support substrate and supporting electronics for reading out radiographic image data captured by the photosensors. The upper and lower shells <NUM>, <NUM>, may be made from carbon fiber or similar material. As shown in <FIG>, the multilayer core is embedded in a core foam base <NUM> (<FIG>). The opening along the width of the shells is closed by positioning an end cap <NUM> therein. Power is supplied to the DR detector by a battery placed in a battery compartment <NUM> formed in the lower shell <NUM>. A battery compartment <NUM> is positioned in the lower shell <NUM> by forming a concave recess in an exterior bottom surface thereof.

With reference to <FIG>, a perspective view of the upper shell <NUM> is shown wherein the upper shell <NUM> is flipped upside down with the multilayer core <NUM> and additional components attached thereto. In one embodiment, an L-shaped grounding plate <NUM> is attached with adhesive either to a lead sheet, if a lead sheet <NUM> (<FIG>) is used; or, in another embodiment, the L-shaped grounding plate <NUM> is attached with adhesive to a stiffening member with adhesive, if a stiffening member <NUM> (<FIG>) is used; or, in another embodiment, the L-shaped grounding plate <NUM> is attached with adhesive directly to the multilayer core <NUM> (<FIG>) if neither a stiffening member <NUM> nor a lead sheet <NUM> is used. The grounding plate <NUM> extends along two perpendicular peripheral edges of the DR detector <NUM>, and may be made from aluminum or other suitable conductor. Gate driver integrated circuitry <NUM> is electrically attached to the grounding plate <NUM> along one edge thereof and read out integrated circuits (ROICS) <NUM> are electrically attached thereto along an adjacent perpendicular edge of the L-shaped grounding plate <NUM>. A thermally conductive pad <NUM> is attached to, and is thermally coupled to, the ROICS <NUM>. The end cap <NUM>, when positioned in the open end of the joined shells <NUM>, <NUM>, thermally engages the thermally conductive pad <NUM> to act as a thermal sink for heat generated by ROICS <NUM>.

<FIG> illustrates a cross-section view of one edge of DR detector <NUM> showing the engagement of bumper <NUM> to flange edge 501b of the upper shell <NUM> and to flanged edge 502b of the lower shell <NUM>. The vertical sidewall portions of upper and lower shells <NUM>, <NUM>, respectively, in the perspective of <FIG>, extend horizontally into bumper <NUM> to form flanged edges 501b, 502b, respectively. The bumper <NUM> secures together both the upper and lower shells, <NUM>, <NUM>, respectively, by compressive force against flanged edges 501b, 502b, and, in addition, adhesive <NUM> is disposed between upper and lower flanged edges 501b, 502b, between the bumper <NUM> and the upper and lower flanged edges 501b, 502b, and between the bumper <NUM> and the upper and lower shells <NUM>, <NUM>. As will be described herein, the multilayer core <NUM> is embedded in a core foam base <NUM> disposed in the interior area of DR detector <NUM>. The bumper <NUM> may be made of an elastomeric material, plastic, rubber, or other suitable impact tolerant material, to absorb shock but should be suitably rigid to hold together the upper and lower shells <NUM>, <NUM>.

<FIG> is a perspective view of the core foam base <NUM>, and other internal electronic components of DR detector <NUM>, which includes shaped recesses <NUM>, cutouts <NUM>, pockets <NUM>, and wirelines <NUM> to receive components of DR detector <NUM>, and which occupies a major volume of the interior of the DR detector <NUM> between upper and lower shells <NUM>, <NUM>. Recesses <NUM> may be used to provide space for folds <NUM> of the ribbon cables <NUM>, which provide for data and electrical communication between ROICS <NUM> and the PCB main control circuitry <NUM> via chip-on-film connectors <NUM>, among other communications; pockets <NUM> may be used for providing space for a battery, for example; wirelines <NUM> may each be used to press a wire <NUM> therein in order to secure the wire in position within DR detector <NUM>. Components of the PCB main control circuitry <NUM> are positioned within the edges of a cutout <NUM>.

<FIG> is a perspective view similar to <FIG> but with a conformal adhesive release layer, film, sheet, or tape, <NUM> place along a periphery of the assembly of <FIG>. The release layer <NUM> covers the ROICS <NUM>, chip-on-film connectors <NUM>, and portion of the DR detector interior assembly. The release layer <NUM> prevents seeping or leaking adhesive from contacting portions of DR detector <NUM> that are covered by the release layer <NUM>. Release layer <NUM> also serves as a sacrificial layer that may be peeled off when separating the upper and lower shells <NUM>, <NUM>, during a repair procedure. Release layer <NUM> also assists in separating the upper and lower shells <NUM>, <NUM>, for repair purposes by preventing excess adhesive or glue from contacting the upper shell <NUM>.

<FIG> is a cross-section cut away view of a portion of DR detector <NUM> without core foam base <NUM> to illustrate positioning of certain described components. <FIG> is a cross-section view near one edge of assembled DR detector <NUM> showing relative positioning of the components of <FIG> from a view perpendicular to the view of <FIG>. Adhered to an interior surface of upper shell <NUM> is a carbon fiber stiffening member <NUM> which strengthens upper shell <NUM> against distortion caused by weight placed thereon. In one embodiment, the upper shell <NUM> is manufactured to have a thicker structure of about <NUM> up to about <NUM> thickness, instead of adhering the stiffening member <NUM> thereto. The other portions of upper shell <NUM>, i.e., sidewall area proximate the flanged edges, and lower shell <NUM> may have half the thickness of the upper shell <NUM>. A buffer layer (foam) <NUM> is positioned below the stiffening member <NUM>. The multilayer core <NUM> is positioned below the buffer layer <NUM>, which includes a scintillator layer, photosensor layer, and a substrate, such as a polyimide substrate. An optional, very thin, mylar sheet <NUM> and conductive grounding sheet <NUM> may be positioned between the buffer layer <NUM> and the multilayer core <NUM>. If included, the mylar sheet <NUM> may be adhered to the buffer layer <NUM>, with the conductive sheet <NUM> below. An optional lead (Pb) layer <NUM> may be positioned under the substrate layer of the multilayer core <NUM>. The grounding plate <NUM> is placed below the optional lead (Pb) layer <NUM>, if the lead layer <NUM> is used, otherwise against the substrate layer of the multilayer core <NUM>. The ROICS <NUM> (<FIG>) are attached to the ground plate <NUM> using posts <NUM>; the gate driver ICs <NUM> are similarly attached to the ground plate <NUM> using posts <NUM>. Foam supports <NUM> may be positioned between the multilayer core <NUM> and the thermal pad <NUM> (<FIG>). The thermal pad <NUM> is in thermal contact with a heat generating IC chip <NUM> mounted on chip-on-film conductor <NUM>. Chip-on-film conductor <NUM> is in electrical communication with both photosensor electronics in the multilayer core <NUM> and ROICS <NUM>, and wraps around intermediate layers as shown in <FIG>. The core foam base <NUM> (<FIG>) supports portions of the assembly as shown including the ROICS <NUM> (core foam base <NUM> not shown in <FIG>) and gate driver PCB <NUM> (<FIG>).

<FIG> shows several of the assembly components described herein in an exploded view. Each individual functional layer, enumerated along the left side of <FIG>, is attached to an adjacent layer using adhesive <NUM>, except for the grounding plate <NUM> and core foam base <NUM>. The upper shell <NUM> is adhered to carbon fiber stiffener <NUM>, which is adhered to buffer layer (foam) <NUM>, which is adhered to an optional, very thin conductive grounding sheet <NUM>, which is adhered to multi layer core <NUM>, which is adhered to optional lead (Pb) sheet <NUM>, which is adhered to L-shaped grounding plate <NUM>, which is supported by core foam base <NUM>. As shown in <FIG>, a carbon fiber bridge structure <NUM> is positioned in a recess on the core foam base, to provide stiffness and to prevent excess loads on PCB main control <NUM> which is positioned directly underneath the carbon fiber bridge <NUM>, in the perspective of <FIG>. The core foam base <NUM> is shaped along one edge <NUM>. to conform to, and support, gate driver integrated circuitry <NUM> (not shown) that is attached to an underside of ground plate <NUM>, in the perspective of <FIG>, as described in relation to <FIG>.

<FIG> and <FIG> correspond substantially to <FIG> and <FIG>, respectively, and so enumeration of the same components will not be repeated in these figures. <FIG> and <FIG> illustrate an optional use of a glass substrate <NUM> as part of the multilayer core <NUM>, rather than a polyimide substrate as shown in <FIG>. Due to the glass substrate being more brittle than a polyimide substrate, an additional stiffening member <NUM> is positioned beneath the multilayer core <NUM>, however, this stiffening member <NUM> may optionally be used with other substrates, such as polyimide. The stiffening member <NUM> may be made from a carbon fiber composite, or other sturdy and stiff material. The stiffening member <NUM> may also include a grounded, thin conductive layer thereon. The grounding plate <NUM> is then adhered to this stiffening member <NUM>.

As described herein, any foam layer components, including foam core base <NUM>, buffer layer <NUM>, foam supports <NUM>, may be made from a lightweight low density foam. Examples of foam materials suitable for use as described herein include ULTEM™ foam, which is a polyetherimide thermoplastic foam, having a density of about <NUM>/m<NUM>, that is thermoformable, manufactured by SABle, based in Riyadh, Saudi Arabia. Another suitable foam is ZOTEK® foam which is a closed cell foam made from poly vinylidene fluoride, having a density of about <NUM>/m<NUM>, that is thermoformable, manufactured by Zotefoams, in Walton, Kentucky, USA.

Claim 1:
A digital radiographic (DR) detector (<NUM>) comprising:
a planar multilayer core (<NUM>) comprising a two-dimensional array of photo-sensitive cells (<NUM>);
a rectangular shaped housing (<NUM>) comprising upper and lower shells (<NUM>, <NUM>) which, when joined together, leave only one open side; and
an end cap (<NUM>) configured to cover the only one open side of the rectangular shaped housing (<NUM>) and
characterized by being further configured to thermally engage a heat source inside the rectangular shaped housing (<NUM>) and to provide a thermal path from the heat source to an exterior of the rectangular shaped housing (<NUM>).