Abstract
A flexible digital radiographic detector with a flexible multi-layered core including a two-dimensional array of photo-sensitive cells, a flexible enclosure enveloping the multi-layered core to facilitate conforming the radiographic detector to a curved surface. A shaped flexible sleeve can receive the digital radiographic detector to conform the detector against a surface of a preselected structure.
Claims
1. A flexible digital radiographic detector comprising: a flexible multi-layered core comprising a two-dimensional array of photo-sensitive cells; and a flexible enclosure enveloping the multi-layered core to facilitate conforming the radiographic detector onto a curved surface.
2. The detector of claim 1, further comprising a shaped flexible sleeve configured to receive the digital radiographic detector wherein the flexible sleeve is shaped to conform against a surface of a preselected structure to be radiographically imaged.
3. The detector of claim 1, wherein the flexible enclosure comprises a polyimide, PET or mylar based material.
4. The detector of claim 1, wherein the flexible enclosure comprises an environmetally protective material selected from the group consisting of a flame retardant material, electrically insulating material, polyetherimide, FR4, or a metalized film.
5. The detector of claim 1, wherein the flexible multi-layered core comprises a thickness between about 500 microns and 2 mm.
6. The detector of claim 1, wherein the flexible multi-layered core comprises a substrate made from polyimide, PET, polyethylene, FR4, mylar, or a conductor.
7. The detector of claim 1, wherein the flexible enclosure is configured on its interior surface to slidably engage the flexible multi-layered core.
8. The detector of claim 1, wherein the flexible enclosure comprises adhesive or a high friction material on at least one interior surface that faces the flexible multi-layered core.
9. The detector of claim 1, wherein the flexible multi-layered core comprises a sensor array layer, a substrate and a slip plane between the sensor array layer and the substrate to facilitate a slidable engagement therebetween.
10. The detector of claim 9, wherein the flexible multi-layered core further comprises a scintillator layer and a slip plane between the scintillator layer and the sensor array layer to facilitate a slidable engagement therebetween.
11. The detector of claim 1, wherein the flexible multi-layered core comprises a scintillator layer, a sensor array layer and a slip plane between the scintillator layer and the sensor array layer to facilitate a slidable engagement therebetween.
12. The detector of claim 1, wherein the flexible multi-layered core comprises a sensor array layer, a substrate and an adhesive layer between the sensor array layer and the substrate.
13. The detector of claim 12, wherein the flexible multi-layered core further comprises a scintillator layer and an adhesive layer between the scintillator layer and the sensor array layer.
14. The detector of claim 2, wherein the shaped flexible sleeve comprises a repositionable adhesive to temporarily hold the flexible digital radiographic detector against the surface of the preselected structure to be radiographically imaged.
15. A flexible digital radiographic detector comprising: a photosensor array layer; a scintillator layer over the photosensor array layer; an integrated circuit electrically coupled to the photosensor array layer; and a flexible bag enclosing the photosensor array layer and the scintillator layer.
16. The detector of claim 15, wherein the flexible bag encloses the photosensor array layer, the scintillator layer and the integrated circuit.
17. The detector of claim 15, further comprising a shaped flexible sleeve configured to receive the digital radiographic detector wherein the flexible sleeve is shaped to conform against a surface of a preselected structure to be radiographically imaged.
18. The detector of claim 17, wherein the shaped flexible sleeve comprises a repositionable adhesive to temporarily hold the flexible digital radiographic detector against the surface of the preselected structure to be radiographically imaged.
19. The detector of claim 15, further comprising a slip plane between the photosensor array layer and the scintillator layer to facilitate a slidable engagement therebetween.
20. The detector of claim 15, further comprising a substrate layer on a side of the photosensor array layer opposite the scintillator layer.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] 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:
[0025] FIG. 1 is a schematic perspective view of an exemplary x-ray system;
[0026] FIG. 2 is a schematic diagram of a photosensor array in a radiographic detector;
[0027] FIG. 3 is a perspective diagram of an exemplary DR detector;
[0028] FIG. 4 is a cross section diagram of an exemplary DR detector;
[0029] FIGS. 5A-5B are perspective views of exemplary core components of a DR detector;
[0030] FIGS. 6A-6B are perspective views of additional exemplary board-side core components of a DR detector;
[0031] FIGS. 7A-7B are perspective views of exemplary sensor-side core components of a DR detector;
[0032] FIGS. 8A-8B are exploded perspective views of final DR detector assembly;
[0033] FIGS. 9A-9B are perspective views of completed DR detector assembly;
[0034] FIGS. 10A-10B are perspective views of exemplary support structures within the DR detector assembly;
[0035] FIGS. 11A-11B are perspective views of exemplary thermal dissipation structures within the DR detector assembly;
[0036] FIG. 12 is a cross section view of the thermal dissipation structured of FIGS. 11A-11B;
[0037] FIGS. 13A-B illustrate an encapsulated flexible image sensor array assembly;
[0038] FIG. 13C is a cross section of the encapsulated flexible image sensor array assembly of FIG. 13B;
[0039] FIGS. 14A-B illustrate a sleeve for the encapsulated flexible image sensor array assembly; and
[0040] FIG. 14C illustrates a flexible sleeve preformed for a preselected structural shape.
DETAILED DESCRIPTION OF THE INVENTION
[0041] Referring to FIGS. 5A and 5B, there is illustrated a multi layered core 500 having a substantially planar, rectangular high density foam layer 502 machined to form recessed pockets 503 on two major sides thereof. A plate 504 formed from a metal, such as aluminum, is positioned in a recessed pocket on a top side of the foam layer 502 as shown in FIG. 5A. The metal plate, or ground plane, 504 may be glued to the foam layer 502 to secure it in position. Recessed pockets 503 are also machined in a bottom side of the foam layer 502 as shown in FIG. 5B, which bottom side pockets 503 will have electronic components placed therein. The foam layer 502 is also machined to form cutouts 505 therethrough wherein printed circuit boards and other electronics may be placed therein and positioned against the ground plane 504, as described herein. The ground plane 504 functions as an electrical ground for the electronic components to be assembled as described herein. As shown in FIG. 5B, the metal ground plane 504 is visible through the cutouts 505.
[0042] The metal ground plane 504 includes a plurality of holes 506, some of which may be threaded, for attaching electrical and mechanical components. Protective end caps 507, also made from the same or similar high density foam as the foam layer 502 are positioned along the edges of the foam layer 502 after electronic components are positioned thereon. As referred to herein, a width dimension of the multi layered core 500 is parallel to the shorter sides thereof as compared to the length dimension which is parallel to the longer sides of the multi layered core 500. The top and bottom sides of the multi layered core 500, as shown in FIGS. 5A and 5B, respectively, together with further detector assembly layers as described herein may be referred to as major surfaces of the multi layered core 500. As shown in FIG. 5A, an area of the top side major surface of the multi layered core 500 made from the foam layer 502 may be about the same or greater than an area made from the metal ground plane 504. According to embodiments of the multi layered core 500 disclosed herein, an area of the metal ground plane 504 may be designed to cover from about 40% of the top side major surface area or up to about 65% of the top side major surface area. The foam used for foam layer 502 and the end caps 507, and other foam components described herein may include high density, thermoplastic, closed cell foams having good heat and flame resistance, heat and electrical insulating properties, a high strength to weight ratio and low moisture absorption. A high density foam such as a polyetherimide based thermoplastic foam or a poly vinylidene fluoride based foam may be used. Alternatively, the foam components may be formed from silicone or rubber.
[0043] FIGS. 6A and 6B illustrate the bottom side of the multi layered core 500 having PCBs placed in the cutouts 505 and recessed pockets 503. The PCBs 602, 606, 608, placed in the cutouts 505 abut the grounding plane 504 and may be connected thereto using screws through the PCB into the holes 506 of the grounding plane 504. The screws may be used to electrically connect the PCBs to the grounding plane 504 or they may be separately electrically connected together. The PCB 604 is positioned in the recessed pocket 503. The PCBs may include, for example, a power distribution electronics PCB 602, a PCB 604 containing read out integrated circuits (ROICs), a PCB 606 for gate driver circuitry, and a PCB 608 having a main processor section. Some of the PCBs having the gate driver circuitry 606 and/or the ROICs 604 may include conductive communication lines (CoFs) 605 extending from the PCBS 604, 606, around an edge of the foam layer 502 and ground plane 504 assembly to enable digital communication between the PCB electronics and the radiographic sensor array on the top side of the multi layered core 500 which includes the two-dimensional array of photo-sensitive cells, as described herein. As shown in FIG. 6B, the protective foam ends caps 507 may be positioned on the edges of the foam layer 502 and ground plane 504 assembly over the CoFs 605.
[0044] FIGS. 7A-7B illustrate the top side of the multi layered core 500. A lead layer 702 is positioned against the top side of the multi layered core 500 to provide shielding against x-rays that may scatter near the DR detector assembly. The lead layer 702 has an area substantially equivalent to an area of a major surface of the multi layered core 500 and, in the embodiments described herein, is the only metal layer in the multi layered core 500 having as extensive an area as the multi layered core 500 itself. The metal grounding plane 504 may, at most, cover about 65% of the area covered by the lead layer 702, as mentioned herein. A sensor layer 704 which may comprise a scintillator layer laminated onto the two-dimensional array of photosensitive cells, is placed on the lead layer 702 and is seated on the top side of the multi layered core 500 as shown in FIG. 7B. The sensor layer 704 may further include a substrate upon which the two-dimensional array of photosensors is formed. The substrate may include a rigid glass substrate or it may be formed as a flexible substrate such as a polyimide substrate. A shock absorbing foam layer 706 is positioned on top of the sensor layer 704 and typically abuts an inside surface of an enclosure for the multi layered core 500. Altogether, the multi layered core 500 may have a thickness of between about one-eighth inch and about one-half inch including the PCB circuitry attached thereto. Without the PCB circuitry attached, the multilayer core comprising the sensor array layer and scintillator may have a thickness between about five hundred (500) microns and two (2) mm.
[0045] FIGS. 8A-8B illustrate the top and bottom sides, respectively, of the multi layered core 500, as assembled, being inserted into an open end 803 of an enclosure, or housing, 800 which enclosure 800 may also be referred to as having corresponding top and bottom sides. A bottom side of the enclosure 800, as shown in FIG. 8B, includes an opening 801 for a battery 802 to be placed therethrough into a corresponding recessed pocket 503 of the foam layer 502 after the multi layered core 500 is fully inserted into the enclosure 800. Subsequently, an enclosure end cap 802 may be positioned in the open end 803 of the enclosure to seal the open end 803 of the enclosure 800 and complete the assembly of the DR detector 900 (FIG. 9). Such an end cap 802 may be formed out of aluminum and positioned in thermal contact with one or more of the PCBs, as described herein. The open end 803 may have a height of between about one-eighth inch and about one-half inch, similar to the thickness of the multi layered core 500 to allow slidable entry of the multi layered core 500 through the open end 803. In one embodiment, the shock absorbing foam layer 706 may be compressed to half its thickness upon the multi-layered core 500 being inserted into the enclosure 800. The enclosure 800, as shown, is a carbon fiber based material such as a twill type of carbon fiber, however, other carbon fiber types of enclosures may be used such as carbon fiber embedded plastics. In addition to carbon fiber, magnesium, aluminum, and plastic enclosures may be used, similar in form as the carbon fiber enclosure 800.
[0046] As shown, the enclosure 800 is a five-sided enclosure formed as a unitary integrated whole having only one open end parallel to a width of the multi-layer core 500. In another separate embodiment, the enclosure 800 may be formed as a four-sided enclosure, such as a flat tube having a rectangular cross section with two opposing open ends. In such an embodiment, the multi-layer core 500 could be inserted into either open end of the four-sided enclosure and two enclosure end caps 802 could be used to seal the opposing open ends of such an enclosure. FIGS. 9A-9B illustrate the top and bottom sides, respectively, of a completed assembly of the DR detector 900, wherein the battery 802 may be removed and replaced through a bottom side of the DR detector 900 as described herein.
[0047] FIGS. 10A-10B illustrate a deflection limiter 1000 used to attach the PCBs 602, 604, 608, to the grounding plane 504 (not shown). The deflection limiter 1000 may include a bottom portion 1001 that may be inserted through a hole in the PCBs 602, 604, 608, into the holes 506 of the grounding plane 504 to secure the PCBs 602, 604, 608, directly to the grounding plane 504. In one embodiment, the bottom portion 1001 of the deflection limiter may be threaded to engage a threaded hole 506 of the grounding plane 504 to screw the PCBs 602, 604, 608, directly to the grounding plane 504. In addition, the deflection limiters 1000 may be disposed in locations selected to prevent excessive deflection of the enclosure 800 by providing a pillar to contact an interior surface of the enclosure 800 when the multi-layer core 500 is inserted therein and so support the enclosure 800 to prevent excessive deflection thereof. An upper surface 1002 of the deflection limiter 1000 may be formed in a convex (domed) shape to prevent edges of the deflection limiter from marring an interior surface of the enclosure 800 coming into contact with the deflection limiter 800. Another feature of the multi layered core 500 used to strengthen rigidity of the DR detector assembly is a carbon fiber stiffening beam 1005 positioned along a width dimension of the multi layered core 500. The carbon fiber stiffening beam 1005 may be attached to the PCBs using brackets or they may be attached to the tops of selectively positioned deflection limiters 1000.
[0048] FIGS. 11A-11B illustrate the multi layered core 500 having a thermally conductive pad 1101 formed in the protective foam end cap 507 that is adjacent the PCB 604 containing the ROICs described herein. The thermally conductive pad 1101 may be used to provide thermal dissipation of heat generated by electronics in the multi layered core 500. Preferably, the thermally conductive pad 1101 is used in conjunction with the aluminum enclosure cap 807 placed on the protective foam end cap 507, as shown in FIG. 11B, and in contact with the thermally conductive pad 1101. FIG. 11B shows the aluminum enclosure cap 807 in position on the protective foam end cap 507 without the enclosure 800 for illustration purposes. FIG. 12 is a close-up cross section of an edge of the DR detector assembly, which edge is parallel to the width of the multi-layer core 500. With reference to FIG. 12, the thermally conductive pad 1101 is in physical contact with an IC chip 1202 of the CoF 605. The CoF 605 extends around an edge of the foam layer 502, as described herein, and is electrically connected to the sensor layer 704 at one end, and is electrically connected to the ROICs of PCB 604 at another end (not shown in FIG. 12). The IC chip 1202 of the CoF 605 may be a source of heat generation that, without a thermal exit pathway to an external environment of the DR detector 900, may cause a malfunction of the CoF 605 electronics, for example. Thus, the thermally conductive pad 1101 provides a portion of a thermal exit pathway by physically contacting the IC chip 1201 and absorbing heat therefrom. When the external aluminum enclosure cap 807 is in position to cover the open end of the enclosure 800, as shown, the aluminum enclosure cap 807 physically contacts the thermally conductive pad 1101 to absorb heat therefrom and functions as another portion of a thermally conductive exit pathway to dissipate heat from the thermally conductive pad 1101 to the external environment.
[0049] FIGS. 13A-C illustrate an embodiment whereby a flexible sensor array assembly 1301 comprising a flexible substrate 1311 is encapsulated in a flexible, enclosed, sealed envelope or bag 1303. Fabrication of the sensor array assembly comprising the flexible substrate 1311 is described in U.S. patent application Ser. No. 16/603,424 entitled FLEXIBLE SUBSTRATE MODULE AND FABRICATION METHOD as detailed above. The envelope 1303 may be made using a polyimide film, such as Kapton developed by DuPont, or Ultem developed by GE and made from polyetherimide (PEI) resins, a very thin glass-reinforced epoxy laminate such as a composite material composed of woven fiberglass cloth with an epoxy resin (FR4), it may be a metalized bag to protect against electromagnetic interference, an electrically insulating material, an environmentally protective material that resists moisture, dust, or other contaminants, PET, a flame retardant material or mylar. The bag is preferably sealed to protectively enclose the sensor array assembly 1301 against contaminants, moisture and other elements such as in a challenging outdoor environment. One layer of the sensor array assembly 1301 may include a scintillator layer 1307 which may include a GOS based or Cesium based scintillator. The sensor array layer 1309 may include a sensor array formed on a polyimide layer, which is further supported by a flexible substrate 1311. The sensor array layer 1309 may be adhered to the flexible substrate 1311 by a layer of adhesive therebetween.
[0050] The envelope 1303 may include an open side whereby the sensor array assembly 1301 is inserted therein. In one embodiment, the envelope 1303 may be formed by placing two sheets, or layers, of a selected encapsulation material one on a top side of the sensor array assembly 1301 and another on a bottom side of the sensor array assembly 1301 and adhering their edges together around the periphery 1305 of the sensor array assembly 1301. In one embodiment, one or both of such sheets may include adhesive to securely attach the encapsulation material to the sensor array assembly 1301 and prevent one or both of the top and bottom sides of the sensor array assembly 1301 from sliding against the envelope 1303. In one embodiment, one or both of such sheets may be laminated to top and/or bottom sides of the sensor array assembly 1301. In one embodiment, the envelope 1303 does not include adhesive so as to allow the sensor array assembly 1301 to slide against the interior surfaces of the envelope 1303 within the periphery 1305 that does not contain adhesive. This sliding engagement may be useful for applications where the sensor array assembly 1301 is bent around a small radius object to be radiographically imaged. In one embodiment, the envelope 1303 may be vacuum sealed around the sensor array assembly 1301. In addition, a slip plane 1313, may be formed between the scintillator 1307 and the sensor array layer 1309 and/or between the sensor array layer 1309 and the substrate 1311 to allow sliding engagement therebetween. The slip plane(s) may be formed by not adhering, i.e., not using adhesive or other constraining materials between, adjacent layers of the sensor array assembly 1301. In one embodiment, a slip plane 1313 may be formed by placing a deformable layer therebetween to facilitate a slidable engagement. The deformable layer may be made from an elastomer such as a thermoplastic elastomer (TPE), thermoplastic polyurethane (TPU), rubber, or a silicone based material, for example. In one embodiment, to facilitate a slight bending of the sensor array assembly 1301 around a large radius object, a slip plane 1313 may not be formed between the scintillator 1307 and the sensor array layer 1309 or the sensor array layer 1309 and the substrate 1311 to maintain a desired fixed or high friction engagement therebetween. The more layers that are affixed to each other in a layered stack, the stiffer the stack becomes. The polyimide portion of the sensor array layer 1309 may include a thickness between about 10 um and about 100 um, preferably between about 30 um and 50 um. The substrate layer 1311 may include a thickness of about 50 um up to about 350 um, preferably between about 150 and 250 um. Characteristics such as durability of the sensor array assembly 1301 may be increased with greater thickness of the substrate 1311, while bendability may be increased with lesser thickness of the substrate 1311. The substrate 1311 may be formed from a material based on polyimide, polyethylene terephthalate (PET), polyimide, polyethylene, mylar, a conductor such as copper or FR4, for example.
[0051] FIGS. 14A-B show a top view of the sealed sensor array assembly 1301 whereby ROICs 1401 are electrically attached to the sensor array and are included within the encapsulation envelope, or bag, 1303 (FIG. 14A) in one embodiment, and, in another embodiment, the ROICs are electrically attached to the sensor array 1309 through perforations in the encapsulation envelope, or bag, 1303, and so are not included within the encapsulation envelope, or bag, 1303. In one embodiment, the sealed sensor array assembly 1301 may be inserted, or placed, within a flexible sleeve 1403 made from a flexible rubber having temperature tolerance such as a high temperature silicone material. The flexible sleeve 1403 may be selected for specific application uses of the sensor array assembly 1301. The flexible sleeve 1403 could be tacky, such as having an adhesive 1404 applied to at least one side thereof, such as a repositionable adhesive, to facilitate repeated attachment of the sensor array assembly 1301 at different positions on a pipe, such as an oil or gas delivery pipe, for radiographically imaging different portions of the pipe. The flexible sleeve 1403 could be shaped, as shown in the example of FIG. 14C, to fit a specific desired structure, such an elbow portion of a pipe, so that, after inserting the sensor array assembly 1301 therein, the sensor array may be quickly conformed against the structure to be imaged. The flexible sleeve 1403 could be shaped by using a mold conformed to a selected structure to be radiographically imaged and fabricating the flexible sleeve 1403 using the conformed mold. The sensor array assembly 1301 may also be inserted into a standard cassette or rigid carbon fiber housing, as described herein, for standard rigid planar detector imaging applications.
[0052] The sleeve 1403 may include a lead (Pb) layer for suitable applications where the radiopaque lead layer may be advantageous. The sleeve may include conductive layers. The flexible sleeve 1403 may be made from temperature resistant material for application in high heat regions or proximate to flames or welding equipment. The flexible sleeve 1403 may be made from UV resistant material, tacky material to assist in being retained in a desired position, or low friction material to facilitate insertion into small gaps.
[0053] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
