CT detector module and CT equipment

Abstract

The invention relates to a CT detector module (2) and a CT device. The CT detector module comprises at least one X-ray converter element (6) having an upper side and a lower side, the X-ray converter element (6) having an X-ray detector layer (8, 9) on the upper side (O) thereof and being fixed on the heat-conducting module carrier (4) on the lower side thereof. The X-ray converter element (6) is in heat-conducting contact with the at least one metal element (12), and the at least one metal element (12) is in heat-conducting contact with the module carrier (4).

Description

Technical Field

[0001] The invention relates to a CT detector module and a CT device. Background Art

[0002] Modern computed tomography (CT) devices have a gantry with a rotatable frame, at which in particular an X-ray source and a detector module for detecting X-ray radiation are arranged. Such a CT detector module usually comprises an X-ray converter element, which has an X-ray sensor layer and, possibly, a layer arranged below it, with an A / D (analog-to-digital) converter. Electronic integration has become an important trend in X-ray converter elements recently. The goal here is to shorten the analog path length between the analog X-ray sensor layer and the A / D converter, which is usually implemented as an ASIC (application-specific integrated circuit). In an integrated X-ray converter, the analog X-ray sensor layer is formed by a suitable sensor layer (e.g. scintillator) in combination with a photodiode, while in a counting X-ray converter, a directly converted semiconductor sensor is used. The A / D converter, which is designed as an ASIC, then generates a digital output signal. In both cases, the integration of the ASIC in a compact structure, in particular a stacked structure, together with the analog X-ray sensor layer brings significant heat sources closer to the X-ray sensor element of the X-ray sensor layer itself.

[0003] Since X-ray sensor elements react very sensitively to thermal fluctuations, thermal management is a key task in the development of modern CT detector modules. The particular challenges of thermal management are: keeping the operating temperature of the CT detector module stable, avoiding temperature gradients between adjacent X-ray converter elements and reducing temperature gradients within each X-ray converter element. These challenges are even more important in counting X-ray converters, since the directly converted semiconductor sensors are additional heat sources and their sensor properties react very sensitively to thermal changes.

[0004] Currently, thermal management is ensured by creating a thermal interface between the X-ray converter element and the metal frame of the CT detector module by means of a thermally conductive adhesive or paste. However, this does not allow a defined amount of heat to be transferred, since the quality of the thermal interface depends on different, less susceptible factors (in particular the thickness of the gap between the X-ray converter and the metal frame) and on the exact distribution of the thermal paste. Summary of the invention

[0005] It is therefore an object of the present invention to provide a CT detector module in which thermal energy can be conducted away from the X-ray converter elements, in particular into the module carrier, as efficiently as possible. It is a further object of the present invention to provide a CT detector module in which temperature gradients within the X-ray converter elements and between adjacent X-ray converter elements are reduced relative to the prior art.

[0006] The present invention achieves the above-mentioned object by means of a CT detector module and a CT device.

[0007] The invention provides a CT detector module, which comprises at least one X-ray converter element having an upper side and an underside, wherein the X-ray converter element has an X-ray detector layer on its upper side and is fixed on a thermally conductive module carrier on its underside. The X-ray converter element is in thermally conductive contact with at least one metal element, and the at least one metal element is in thermally conductive contact with the module carrier.

[0008] Therefore, in the CT detector module according to the invention, the thermal contact between the X-ray converter element and the module carrier is established by metal-to-metal contact, thereby having a high thermal conductivity. The metal-to-metal contact is established between the X-ray converter element and the intermediate element composed of metal (i.e. the metal element), and is also established between the metal element and the module carrier. The module carrier can be a metal frame with convection cooler elements, such as cooling fins. By using at least one metal element, the thermal interface between the X-ray converter element and the module carrier can be precisely defined, because the metal contact position can be precisely determined. The metal-to-metal thermally conductive contact is preferably formed without gaps in order to achieve the highest possible heat conduction. The metal-to-metal contact can be established after the CT detector module has been fixed to the module carrier with the required accuracy (e.g. glued, in particular glued by means of UV adhesive). In many cases, the thermal contact can be further improved by, for example, thermally conductive paste or pads or adhesive or solder material to increase the thermal contact.

[0009] According to one embodiment, the metal element is not solder. In particular, the metal element is a dimensionally stable element which may, for example, take the form of a spring, a metal plate, a pin, a screw, a spring element or the like.

[0010] In an advantageous embodiment of the invention, the heat is discharged from each X-ray converter element not only at one point on the underside, but at a plurality of points and / or in a planar manner. The term "planar" means that the contact is not only point-shaped, but takes place over a larger area of ​​the underside of the X-ray converter element, for example over 10%-90%, preferably 20%-80%, more preferably 30%-60% of the area of ​​the underside of the X-ray converter element.

[0011] The X-ray converter element has an X-ray detector layer on its upper side. The X-ray detector layer faces the X-ray source and is designed to detect X-rays. The X-ray detector layer can include a directly converted (semiconductor) X-ray sensor layer, for example with CdTe, CdZnTe, CdTeSe, CdZnTeSe, CdMnTe, GaAs, Si or Ge as semiconductor materials. The X-ray detector layer can also include a suitable sensor layer for converting X-ray radiation into light and an optically coupled photodiode, in particular one or more photodiode arrays. Here, scintillator materials such as GOS (Gd2O2S), CsJ, YGO or LuTAG are usually used as materials. The X-ray detector layer can also include a layer with an analog-to-digital converter, to which the X-ray sensor layer is applied, wherein the A / D converter layer can be implemented in one or more ASICs. The X-ray detector layer can be applied on a substrate, also called a substrate, such as a circuit board or a ceramic or glass substrate, which then forms the bottom side of the X-ray converter element. The X-ray converter element is fixed on a heat-conducting module carrier at its bottom side.

[0012] The module carrier is particularly made of metal, for example of an aluminum die casting. The module carrier can be configured to mechanically fasten the corresponding detector module in a CT device comprising the detector module. For this purpose, corresponding fastening mechanisms and alignment mechanisms can be provided at the module carrier. The module carrier is preferably configured as a metal heat sink, which is configured to stabilize the temperature of the detector module and to conduct heat away from the X-ray converter element. For example, the module carrier can be equipped with suitable cooling fins. The CT detector module is typically part of a rotating gantry of a CT device.

[0013] The X-ray converter element can be fixed to the module carrier by means of an adhesive, for example a UV adhesive, wherein other fixing means, for example screws, are also possible. A plurality of X-ray converter elements can also be fixed to the module carrier, so that the module carrier is thus "tiled" by arranging the X-ray converter elements one after the other.

[0014] The invention is also characterized in that the heat generated in the x-ray converter element and in particular in the x-ray detector layer is effectively dissipated into the module carrier via the novel metal element.

[0015] According to a preferred embodiment, the bottom side of the X-ray converter element, which is in thermal contact with at least one metal element, is at least partially provided with a metal lining. As a result, the heat conduction to the module carrier can be improved and, if necessary, a large-area contact to the metal element can be established, thereby further improving the heat conduction to the module carrier. The metal lining can be formed, for example, by a coating with a metal with good thermal conductivity (for example, gold, silver or copper). The metal lining can be a so-called "metallized thermal pad". The thermally conductive lining can cover a part or even the entire bottom side of the X-ray converter element, in particular, the thermally conductive lining is arranged at the position where the metal element is in contact with the X-ray converter element. The metal lining can be connected to the A / D conversion layer and / or the X-ray sensor layer through a metallized through-hole in the substrate of the X-ray detector layer and / or the A / D conversion layer, so that heat can be conducted from there to the metal lining. This is also called thermal via technology. The metallized through-hole can be, for example, a contact hole in the substrate.

[0016] According to one embodiment, at least one metal element has a flat metal element, in particular a metal plate, which in a first region rests against the underside of the X-ray converter element and in a second region rests against the module carrier. The embodiment as a flat metal element is advantageous in production and ensures very good heat conduction, in particular when the metal plate rests against the element to be connected at a planar region on its upper side and / or lower side. The flat metal element can, for example, have two legs, one of which rests against the underside of the X-ray converter element and the other leg rests against the module carrier, wherein the two legs can, for example, form an angle of about 90°. Thus, the cross section of the metal plate can be L-shaped or T-shaped. The metal element can also be a profile element, which can also have two legs. The second leg can be arranged in a recess of the module carrier and, if necessary, fixed there, for example, by a fixing element such as a screw. The recess can, for example, be a gap, into which the second leg of the metal element is pushed. In another embodiment, the metal element, in particular a metal plate, forms a disk which is inserted between the bottom side of the X-ray converter element and the top side of the module carrier and is thus in thermal contact with the X-ray converter element with its top side and in thermal contact with the module carrier with its bottom side. In this embodiment, a fixing means or a spring element can also be provided which ensures that the contact is established. Such a plate can also be just one of a plurality of heat-conducting metal elements, in particular the fixing means can also consist of metal and thus form part of the thermal bridge.

[0017] According to one embodiment, the at least one metal element has a spring element, which is pressed against the underside of the X-ray converter element by a restoring force. The spring element can be formed by a metal sheet and have the above-mentioned properties. For example, a metal sheet with a raised L-shaped prebend can be arranged between the X-ray converter element and the module carrier so that the metal sheet presses against the underside of the X-ray converter element. An embodiment in which the metal element has a metal sheet or a spring element is particularly advantageously combined with an embodiment in which the underside of the X-ray converter element is at least partially provided with a metal lining. The portion provided with the lining can, for example, constitute 20%-80%, preferably 40%-60%, of the underside of the X-ray converter element.

[0018] The spring element can be inserted as an insert into the module carrier, in particular into a recess of the module carrier. When assembling the CT detector module, the X-ray converter element can be glued to the module carrier in a first step, preferably with the highest possible positional accuracy. Here, a fast-curing adhesive, such as a UV adhesive, can be used. During the gluing, the spring element or the metal plate is preferably already inserted into the module carrier, but in a specific embodiment, it can also be pushed in from the side after the gluing process.

[0019] The metal-to-metal surface contact can be increased by pressing the corresponding abutting areas against each other, in particular by means of a fixing element or an element with a restoring force, such as a spring. For example, a screw, such as a grub screw, can be screwed into a bore in the module carrier, which extends up to the second area of ​​the metal plate or the spring element. As a result, the area can be pressed against the module carrier. In addition, heat conduction also occurs through the screw itself. Similarly, another bore can reach up to the first area of ​​the metal element. The grub screw inserted through the bore can be pressed against the first area of ​​the metal element at the bottom side of the X-ray converter element.

[0020] Alternatively, the metal element can also be thermally connected to the X-ray converter element and the module carrier at its planar contact area by any fixing mechanism, wherein the metal element should be in contact with the lower side of the X-ray converter element and the module carrier at the contact area. The fixing mechanism can be, for example, a screw, a rivet, a piston spring, a solder or a reactive solder. Reactive solder can be understood as a process of applying a multilayer system to the surface to be connected, the multilayer system usually consisting of two different metals, the metal cups are alternately superimposed on each other, and the metals are, for example, nickel / aluminum, aluminum / titanium or copper / silver. The thermal energy required to melt the solder is triggered by a self-propagating exothermic reaction of the multilayer system. The reaction is usually triggered by an energy pulse, for example, by high temperature, mechanical pressure, electric sparks or laser pulses. Therefore, in the present invention, a corresponding reactive solder layer can be applied to the following area of ​​the metal element, where the reactive solder is in contact with the X-ray converter element and the module carrier. If the CT detector module is assembled in such a way that the X-ray converter element is glued to the module carrier at a predetermined position, a reaction can be initiated and a tight metallic connection can be established between the metal element and the X-ray converter and the module carrier. In this embodiment, a metal lining on the underside of the X-ray converter element has also proven to be advantageous. Alternatively, the reactive solder can also be ignited before the X-ray converter element is mounted.

[0021] According to one embodiment, at least one metal element is fixed to the module carrier by a fixing mechanism. The fixing mechanism preferably consists of metal and thus also forms a thermal bridge or part of the metal element. The fixing mechanism can in particular be a screw, a rivet, a clamp, a pin or a piston spring, a solder or also a reactive solder. Preferably, the fixing mechanism is a screw, which is introduced into a bore in the module carrier and presses against the metal element or presses the metal element against a part of the module carrier in order to fasten the metal element. In particular, the fixing mechanism can be a metal screw, for example a grub screw.

[0022] According to one embodiment, at least one metal element includes at least one fixing mechanism, which is arranged at the module carrier and is pre-tensioned relative to the metal lining on the bottom side of the X-ray converter element or relative to the planar metal element arranged at the bottom side of the X-ray converter element. In the embodiment, the fixing element can represent the main thermal conductor. The fixing element can be configured as described above, that is, it is configured as a screw, a rivet, a clamp, a pin or a piston spring. In one embodiment, the fixing element is a screw, which is screwed into a threaded bore in the module carrier. In particular, it can be a bore extending from the bottom through the module carrier through the module carrier to the bottom side of the X-ray converter element. The borehole can be perpendicular to the bottom side of the X-ray converter element, for example. If a metal screw is screwed into the borehole, the metal screw can reach the bottom side of the X-ray converter element, thereby establishing thermal contact. When manufacturing the CT detector module, the X-ray converter element can be pasted to the module carrier in a first step. Preferably, a metal lining is present on the underside of the X-ray converter element, which is preferably connected to the heat source, in particular the X-ray detector layer, by means of thermal via technology. The introduced metal screw or the screw with a metal piston spring then acts as a heat conducting component between the underside of the X-ray converter element and the module carrier. Metal-to-metal surface contact can be achieved by prestressing the screw relative to the underside of the X-ray converter element, in particular relative to the metal lining.

[0023] According to one embodiment, at least one metal element is inserted into a recess in the module carrier or fixed to the side wall of the module carrier. The side wall is in particular at least substantially perpendicular to the upper and lower walls of the X-ray converter element. The recess can accommodate a planar metal element, such as a metal plate. For example, a metal element in the form of a metal block can be fixed to the side wall of the module carrier, for example, by a fixing mechanism such as a screw, and the metal block can also be attached to the lower side of the X-ray converter element from below or pressed against the X-ray converter element. Here, the X-ray converter element can be pasted to the module carrier in the first step. The lower side of the X-ray converter element can have a metal lining, which can be connected to a heat source by thermal via technology. For example, a metal element configured as a metal insert or a metal block can thermally connect the lower side of the X-ray converter element to the module carrier. Here, a metal-to-metal contact is established by pressing the metal insert against the lower side of the X-ray converter element and then clamping the metal element in the position in the module carrier, for example, by a fixing mechanism such as a screw. Alternatively, other connection techniques may be used to hold the metal block in its final position.

[0024] According to one embodiment, the at least one metal element is inserted into a recess in the module carrier or is fixed to a side wall of the module carrier. Particularly high heat conduction is possible by the metal element being inserted into the recess or resting against the side wall. The side wall of the module carrier can be a wall extending perpendicularly to the underside of the X-ray converter element. The metal element can be designed, for example, in a square shape, so that it contacts the underside of the X-ray converter element and the module carrier with two sides lying next to each other. The recess can be a slot into which a planar metal element (for example a leg of a metal sheet) is inserted.

[0025] According to one embodiment, the at least one metal element has a reactive solder, which connects the underside of the X-ray converter element to the module carrier in a thermally conductive manner. The reactive solder can form the metal element. However, in addition to a planar metal element (e.g. a metal plate) inserted between the X-ray converter element and the module carrier, a reactive solder can also be used. In the above-described embodiment, the thermally conductive paste is replaced by a soldering technique. Alternatively, instead of the reactive solder, a conventional solder can be used, which connects the underside of the X-ray converter element to the module carrier in a thermally conductive manner.

[0026] In the embodiment described, the metal interface can be realized by carrying out a local selective soldering process, which connects the underside of the X-ray converter element and the metal lining arranged there, if present, to the metal surface of the module carrier. In the embodiment described, the entire X-ray converter element can be glued to the module carrier again with high position accuracy in a first step. On the underside of the X-ray converter element, one or more locations are preferably provided with a metal lining, which can preferably be connected to a heat source by means of thermal via technology. The selective soldering process can be carried out with the aid of a reactive solder. When the reactive solder is ignited, the solder connection is directly implemented as a heat conducting element between the underside of the X-ray converter element and the module carrier. The ignition of the reactive solder can be triggered by known ignition techniques, such as laser or heating (for example by sparks or flames). Alternatively, instead of the reactive solder, a conventional solder can be used, which is either introduced into the gap between the underside of the X-ray converter element or the metal lining arranged there and the upper side of the module carrier after gluing. Alternatively, it is also possible to insert a conventional solder into the gap before the gluing step and then simply heat it by conventional thermal techniques (eg laser or (less preferred) flame) in order to produce the metallic connection.

[0027] According to one embodiment, the X-ray converter element has a substrate at its bottom side, the substrate having a recess, through which at least one metal element is directly in thermal contact with the X-ray detector layer. In the embodiment, the substrate of the X-ray converter element has a continuous recess, especially in the middle. For example, it can be a rectangular, circular or elliptical recess that allows the edge element to stand upright. In particular, the recess is configured as a through hole, so that the metal element can be directly guided through the recess to the bottom side of the X-ray detector layer. In this way, heat can be more effectively conducted. The metal element can be configured as described herein, for example, as a spring element, as a metal plate, a metal block, a screw, etc. The bottom side of the X-ray detector layer is preferably at least partially provided with a metal lining for the form of a coating or a metallized heat pad, which can in turn be connected to the X-ray detector layer or the X-ray sensor layer through a metallized through hole. Therefore, the metal element acts as a thermal bridge between the X-ray detector layer and the module carrier. The connection between the metal element and the bottom side of the X-ray detector layer can be carried out in particular in the manner described here with respect to other embodiments. For example, screws may press the metal surfaces against each other. Alternatively, a connection technique such as reaction welding may be used beforehand or as a final step.

[0028] According to one embodiment, the X-ray converter element has a substrate on its underside, wherein the substrate has a thermal bridge between the underside of the substrate and the X-ray detector layer at least in its region of thermally conductive connection to the at least one metal element. The thermal bridge can be, for example, a metallized through-hole which ensures an improved heat flow between the X-ray detector layer and the module carrier. The thermal bridge can also be formed by an additional metal layer.

[0029] The present invention provides a robust and efficient thermal management design for the integration of X-ray converter elements into a CT detector module by consistently using gapless metal-to-metal contacts. As a result, thermal conductivity is significantly improved relative to known solutions using thermal boxes or thermal pastes. By avoiding gaps between individual elements of the CT detector module or bridging the gaps by means of metal elements, thermal resistance can be reduced. As a result, improved temperature uniformity over the entire CT detector module can be achieved while reducing the temperature. Signal performance and stability are thus improved.

[0030] According to one embodiment, the X-ray converter element has a substrate on its underside, which has galvanically plated through-holes, which form a thermal bridge between the underside of the substrate and the X-ray detector layer, thereby further improving the heat conduction.

[0031] According to one embodiment, the module carrier has cooling fins. This is useful in order to dissipate the heat introduced into the module carrier to the surrounding air. The temperature of the CT detector module is thereby further reduced.

[0032] The invention also relates to a CT device having at least one CT detector module according to the invention, in particular a plurality of CT detector modules arranged in a row in the direction of rotation. All embodiments and advantages mentioned with reference to the CT detector module can also be used for the CT device, and vice versa. The CT detector module is in particular part of a rotating gantry of the CT device. The CT device can have other common components, such as an X-ray source, a patient bed, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Now, the present invention will be explained in more detail based on embodiments with reference to the attached drawings.

[0034] In the accompanying drawings:

[0035] Figure 1 shows a schematic cross-sectional view through a CT apparatus according to one embodiment of the present invention;

[0036] Figure 2 shows a schematic cross-sectional view through a CT detector module according to the prior art in the longitudinal and transverse directions;

[0037] Figure 3 shows a cross-sectional view in longitudinal and transverse direction through a CT detector module according to a first embodiment of the present invention;

[0038] Figure 4 shows a cross-sectional view in longitudinal and transverse direction through a CT detector module according to a second embodiment of the present invention;

[0039] Figure 5 shows a cross-sectional view in longitudinal and transverse direction through a CT detector module according to a third embodiment of the present invention;

[0040] Figure 6 shows a cross-sectional view in longitudinal and transverse direction through a CT detector module according to a fourth embodiment of the present invention;

[0041] Figure 7 shows a cross-sectional view in longitudinal and transverse directions through a CT detector module according to a fifth embodiment of the present invention;

[0042] Figure 8 A cross-section through a CT detector module according to a sixth embodiment of the invention is shown in longitudinal and transverse direction.

[0043] In the figures, identical parts are provided with the same reference symbols. DETAILED DESCRIPTION

[0044] Figure 1A schematic cross section through a CT device 1 according to one embodiment of the present invention is shown. A rotating gantry 20 is supported in a device frame 22. The gantry 20 is designed to rotate around an examination space 5 having a bed 24, on which a patient can be supported. A plurality of detector modules 2 are arranged in the rotating gantry 20, each of which comprises a module carrier 4, the side of which facing the examination space 5 is covered with an X-ray converter element 6. An X-ray source 26 is located on the side opposite to the CT detector module 2.

[0045] The following figures each show a schematic cross-sectional view through a CT detector module 2, more precisely a section in the longitudinal direction on the left and a section in the transverse direction on the right. In the following figures, the upper side of the detector module marked with O is the side facing the examination space 5, and the lower side of the detector module marked with U is the side facing away from the examination space. Figure 2 On the left, a schematic cross-sectional view is shown in the only partially connected state to illustrate the adhesive connection, while on the right, the connected state is shown. Figure 2 As can be seen in the figure, the detector modules 2 each have a heat-conducting module carrier 4, which is particularly made of metal. Here, it can be a casting made of an aluminum alloy, for example. In addition to the X-ray converter element 6, the module carrier 4 can also carry a power supply device and also have a cooling plate to effectively conduct the absorbed heat. The X-ray converter element 6 has X-ray detector layers 8 and 9 on the upper side O. The X-ray detector layer includes an X-ray sensor layer 8, which can be made of CdTe, for example. Below it is a layer composed of an A / D converter 9, such as an A / D electrical sensor layer. These sections 9 can be configured as ASICs. The X-ray sensor layer 8 and the A / D converter layer 9 are connected to each other via an electrically conductive connection (for example, a solder connection). The intermediate space can also be filled with the so-called "bottom filling", that is, a filling material. The filling material can, for example, have an epoxy compound, a plastic material, a composite material or a (pre) polymer or other material. For example, a conductive adhesive connection can also be provided. The A / D converter layer 9 is connected to the substrate 10 via an interface layer 21, and there is an electrical terminal for forwarding a signal from the A / D converter layer in the cross-sectional layer. The substrate 10 is, for example, a printed circuit board 10, which can be used in particular as a redistribution layer and is also referred to below as substrate 10. The substrate 10 can also be designed differently, for example as a ceramic substrate or the like. 34 schematically represents a plug connector, via which the data processed in the substrate 10 can be exported. In this case, for example, a ribbon cable is plugged into the plug connector 34. This can only be arranged on one side of the detector module 2. The arrangement of the plug connector 34 on both sides is shown here. In addition, the module carrier 4 can have a recess 50, which allows the plug connector to be placed more easily. In the following Figures 3 to 8, the recess 50 in the module carrier 4 is no longer shown for the sake of clarity, but can be present in the same way. In addition to the embodiment shown here, in which the recess 50 is combined with the plug connector 34, other embodiments and in particular arrangements on the detector module 2 can also be obtained, which enable the data to be derived from the substrate 10 and which, for example, do not require the recess 50. The module carrier 4 can be, for example, an aluminum die casting.

[0046] Figure 2 The prior art is shown, according to which the X-ray converter element 6 is fixed to the module carrier 4 at 30 by means of an adhesive, for example a UV adhesive. These adhesive locations 30 can be arranged at the outer edge of the X-ray converter element 6. A heat-conducting paste or heat-conducting adhesive 32 is used between them, which is arranged in the adhesive gap 11 between the substrate 10 and the module carrier 4. However, this has the following disadvantages: the amount of heat-conducting paste 32 and the gap width 11 can fluctuate due to manufacturing tolerances, and thus the gap filling exhibits a thermal connection of different strengths. In addition, if the adhesive volume is large and the gap is small, the heat-conducting paste 32 may be partially pressed out of the gap 11 during production, so that the heat conduction between the X-ray converter element 6 and the module carrier deteriorates uncontrolled. A plurality of X-ray converter elements 6 can be adhered to the module carrier in a planar manner, so to speak, the module carrier is flat. Here, the substrate 10 can also extend over a plurality of X-ray converter elements 6, for example, or can be associated with only one X-ray converter element in each case.

[0047] The object of the invention is to improve the thermal connection between the X-ray converter element 6 and the module carrier 4. This is done in particular by increasing the heat transfer via the adhesive gap 11 between the X-ray converter element 6 and the module carrier 4 and making the heat transfer better adjustable.

[0048] The first embodiment of the present invention is Figure 3. Here, on the one hand, a metal lining 14 is provided on the lower side of the substrate 10, for example in the form of a coating or a metallized thermal pad. The purpose of the metal lining is to increase the area over which heat can be output from the X-ray converter element 6 to the module carrier 4 and / or to improve thermal conduction. The metal lining can also be arranged in multiple sub-areas in a manner distributed over the lower side of the X-ray converter element, for example in the form of multiple coating face segments or multiple thermal pads. The metal lining can be, for example, a gold layer. The thickness of the metal lining can be, for example, 0.5μm-20μm, preferably 1μm-10μm. The metal lining 14 can be connected to the upper layers 8, 9 of the X-ray converter element, in particular via thermal via technology. However, there can also be embodiments without such a metal lining. Here, in the absence of a metal lining, a thermally conductive connection by means of thermal via technology can cause improved thermal conduction from the upper layers 8, 9. In addition, the detector module 2 has a new metal element 12, which is inserted into a recess 13 in the module carrier 4 as shown on the right. In the example shown, it is a T-shaped, planar metal element having a leg 12a, which is arranged parallel to the upper side of the sensor layer and rests against the lower side of the substrate or against the metal lining. The other leg 12b is inserted into the recess 13 and contacts the module carrier 4 there. As shown on the right, the module carrier 4 can also be provided with an optional metal lining 44, for example a gold layer, at the contact surface with the metal element 12, which further increases the thermal conductivity. The metal element 12 can first be inserted loosely into the recess 13, where it initially still has a gap. In order to ensure that the metal element 12 is pressed against the lower side of the X-ray converter element 6 with its leg 12a and against the module carrier 4 with its leg 12b, as shown on the right, a grub screw 16 can be used, which can be introduced into the corresponding threaded bores 17, 19. The bore 17 extends, for example, from the side of the module carrier 4 to the recess 13, so that a grub screw 16 introduced therein, when tightening the leg 12b of the metal element, is pressed uniformly and in a planar manner against the opposite side of the recess 13 and thus against the module carrier 4. The second threaded bore 19 leads from the lower side of the module carrier 4 to the lower side of the substrate 10, so that a grub screw (not shown) introduced therein presses the leg 12a of the metal element against the lower side of the substrate or against the metal covering. Therefore, at this point, a uniform and planar thermal coupling is also ensured. The metal element 12 can also be designed in an L-shape, for example as a bent metal plate. In this case, the metal element can also be designed as a spring element, i.e. with a preload, by means of which the spring element is pressed against the lower side of the substrate 10. Figures 3 to 8 In the embodiment of , the X-ray converter element 6 is also pre-fastened and mechanically aligned on the module carrier 4 by means of an adhesive 30, for example an adhesive site consisting of a UV adhesive. However, additional fastening can also be performed, for example by means of screws.

[0049] Figure 4 A further embodiment is shown in which the heat-conducting metal element 12 is substantially formed by fixing means 18 , in this case by grub screws 18 , which are screwed into corresponding threaded bores 19 in the module carrier 4 until they press against the underside of the base 10 .

[0050] In this embodiment, the X-ray converter element 6 can first be glued to the module carrier 4 by means of an adhesive 30. In this embodiment, the metal lining 14 is also preferably present on the underside of the substrate 10, at least at the location of the threaded bore 19. After gluing and hardening, a grub screw 18 or a screw with a metallic piston spring is introduced into the bore 19 and then acts as a heat-conducting element between the underside of the substrate 10 and the module carrier 4. In this case, a metal-to-metal contact is formed by pressing the fixing means 18 against the metal lining 14. In a variant embodiment, another planar metal element can also be inserted as part of the metal-to-metal contact between the underside of the X-ray converter element 6 and the upper side of the module carrier 4, and thus is in heat-conducting contact with the X-ray converter element 6 with its upper side and in heat-conducting contact with the module carrier 4 with its underside. The fixing means 18 then ensures the establishment of contact by pressing and effectively transfers heat into the module carrier.

[0051] Figure 5 Another embodiment is shown in which the heat-conducting metal element 12 is formed by a block-shaped insert 12 c. The insert is pressed onto the module carrier 4 from the side and held in place by screws 16. Instead of screws, other connection techniques can also be used, such as clamps, in order to hold the metal element 12 in contact with the underside of the substrate or with the metal lining 14 optionally applied there. Even in this embodiment, the X-ray converter element 6 is held on the module carrier 4 by an adhesive 30.

[0052] Figure 6 A further embodiment is shown, in which the metal element 12 is realized by a layer 42 between the substrate 10 and the module carrier 4 or the optional metal lining 14. This can be solder. Before the X-ray converter element 6 is glued to the module carrier 4, the solder can be introduced into the gap 11. After gluing, the solder can then be melted, for example, by heating or laser. Alternatively, the layer 42 can also be formed by a reactive solder layer, which then only needs to be ignited and no further heat transport is required due to the exothermic reaction. As a result, a direct metal-to-metal connection between the bottom side of the X-ray converter element and the module carrier 4 is possible. In the material-fit connection, the metal lining 14 on the bottom side of the substrate is not required.

[0053] Figure 7Another embodiment is shown, in which, in addition to the cross-sectional view, a top view of the substrate 10 is shown without the electrical connection points of the layer 21. In this embodiment, the metal element 12 is in direct contact with the A / D converter layer 9 via the region 12e and is thus closer to the heat source in the X-ray detector layers 8, 9. This is achieved in that the substrate 10 has a continuous recess 43 through which the metal element 12 extends.

[0054] As a result, the heat can be dissipated more effectively, since the heat can be absorbed by the metal element 12 closer to the heat source. The base 10 is then configured in a ring shape. The metal element 12 can be connected to the base 10. Figure 3 The embodiment shown is designed similarly, namely as a T-shaped metal element, whose leg 12e is pressed onto the underside of the A / D converter layer 9 and whose other leg 12f is accommodated in the recess 13 of the module carrier 4. By means of grub screws 16 introduced into threaded bores 17 and 19, the metal element 12 is pressed onto the corresponding surfaces, namely onto the underside of the A / D converter layer 9 and onto the side walls of the recess 13, in order to ensure metal-to-metal surface contact. Instead of grub screws 16, reactive solders can also be used. In addition, a metal lining can also be provided on the A / D converter layer 9 in order to achieve a further improved heat conduction.

[0055] Figure 8 Another embodiment is shown, which is similar to Figure 3 , because here too a T-shaped metal element 12 with legs 12a, 12b is used, which is inserted into a recess 13 in the module carrier 4. In this embodiment, however, the substrate 10 has a heat conducting area 46, which in this case is located in the middle of the substrate. Figure 8 The lower view in FIG. 4 shows substrate 10 without the electrical connection sites of layer 21. The heat flow between sensor element 8 and module carrier 4 is further improved by heat conducting layer 46. This can be ensured, for example, by the presence of additional metal layers and / or metallized through-holes 48 in heat conducting region 46.

[0056] Regardless of the grammatical part of a particular term, it includes persons / things having masculine, feminine, or other genders.

Claims

1. A CT detector module (2) comprising at least one X-ray converter element (6) having an upper side and an underside, wherein the X-ray converter element (6) has an X-ray detector layer (8, 9) on its upper side (O) and is fastened on its underside to a heat-conducting module carrier (4), characterized in that The X-ray converter element (6) is in thermally conductive contact with at least one metal element (12), and the at least one metal element (12) is in thermally conductive contact with the module carrier (4).

2. The CT detector module (2) according to claim 1, characterized in that: The underside of the X-ray converter element (6) which is in thermally conductive contact with the at least one metal element (12) is at least partially provided with a metal lining (14).

3. The CT detector module (2) according to claim 1 or 2, characterized in that: The at least one metal element (12) comprises a flat metal element, in particular a metal plate, which in a first region (12a) bears against the underside of the x-ray converter element (6) and in a second region (12b) bears against the module carrier (4).

4. The CT detector module (2) according to any one of the preceding claims, characterized in that The at least one metal element (12) has a spring element which is pressed against the underside of the x-ray converter element (6) by a restoring force.

5. The CT detector module (2) according to any one of the preceding claims, characterized in that The at least one metal element (12) is fixed to the module carrier (4) via a fixing means (16).

6. The CT detector module (2) according to any one of the preceding claims, characterized in that The at least one metal element (12) comprises at least one fixing means (18) which is arranged on the module carrier (4) and is prestressed relative to a metal lining (14) on the underside of the X-ray converter element (6) or relative to a planar metal element arranged at the underside of the X-ray converter element (6).

7. The CT detector module (2) according to any one of the preceding claims, characterized in that The at least one metal element (12) is inserted into a recess (13) in the module carrier (4) or is fixed to a side wall of the module carrier (4).

8. The CT detector module (2) according to any one of the preceding claims, characterized in that The at least one metal element (12) comprises a solder or reactive solder (42) which connects the underside of the X-ray converter element (6) to the module carrier (4) in a thermally conductive manner.

9. The CT detector module (2) according to any one of the preceding claims, characterized in that The X-ray converter element has a base plate (10) on its underside, which has a recess (43) through which the at least one metal element (12) is directly in thermally conductive contact with the X-ray detector layers (8, 9).

10. The CT detector module (2) according to any one of the preceding claims, characterized in that The X-ray converter element (6) has a base plate (10) on its underside, wherein the base plate (10) has, at least in its region (46) in which it is thermally connected to the at least one metal element (12), a plurality of thermal bridges (48) between the underside of the base plate and the X-ray detector layer (8, 9).

11. The CT detector module (2) according to any one of the preceding claims, characterized in that The X-ray converter element (6) has a substrate (10) on its underside, which has a plurality of electroplated through-holes (48) which form a thermal bridge between the underside of the substrate and the X-ray detector layer (8, 9).

12. The CT detector module (2) according to any one of the preceding claims, characterized in that The module carrier (4) has a plurality of cooling fins.

13. A CT device (1) comprising at least one CT detector module (2) according to any one of the preceding claims.

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