Positioning of the sensor unit using a positioning substrate

Abstract

The present invention relates to a method for positioning a sensor unit in a detector module of a CT device, the method comprising at least the following steps: arranging a connection layer on a positioning substrate, positioning at least one sensor unit and preferably at least one reading unit relative to the positioning substrate to form a sensor reading device, wherein the sensor unit is temporarily connected to the positioning substrate in a fixed position by means of the connection layer, preferably positioning at least one electronic circuit board, and establishing a conductive connection between the electronic circuit board and the contacts of the reading unit to obtain at least one sensor circuit board, positioning the sensor unit relative to a module carrier by means of the positioning substrate and preferably positioning the sensor circuit board, and placing the sensor unit on the module carrier to obtain a detector module. The present invention also relates to a detector module and the use of a positioning substrate for positioning a sensor unit.

Description

Technical Field

[0001] The invention relates to a method for positioning a sensor unit in a detector module of a CT (computed tomography) system by means of a positioning substrate. Background Art

[0002] Imaging with X-ray and CT equipment is undergoing a continuous process of improvement. The devices are becoming better and better on the market, which in turn leads to ever-increasing demands on manufacturing precision.

[0003] Especially for counting CT detectors, the manufacturing process shown below is known from practice. First, a so-called hybrid structure is manufactured, which includes both a sensor unit or the actual detection material and a reading unit, i.e., an ASIC, for example. The sensor unit is usually conductively connected to the reading unit by means of a reflow soldering process, wherein the solder is previously introduced between the two units in the form of a so-called ball grid array (BGA). In a further reflow soldering process step, the reading unit of the hybrid structure thus manufactured is applied to a substrate while introducing other ball arrays as solder and conductively connected to the substrate. For example, electrical connections can be redistributed with the aid of the substrate. Alternatively or additionally, other electronic components for processing and transmitting sensor data can be arranged thereon. The arrangement of the substrate and multiple hybrid structures is usually referred to as a sensor board or sensor circuit board.

[0004] In the above-mentioned manufacturing process, the manufacturing accuracy of the individual components is important on the one hand, and the accuracy of the self-orientation ("floating") of the components during the welding process is important on the other hand.

[0005] However, very high demands are placed on manufacturing tolerances, because even small deviations in the subpixel range, either in the direction within the detection plane (i.e. the distance between the sensor units) or in the direction perpendicular to the detection plane (i.e. the (height) steps between the individual sensor units), can have an adverse effect on the imaging.

[0006] Document DE 10 2018 200 845 A1 discloses an assembly method for producing an X-ray detector, wherein according to the method a plurality of sensor surface elements made of an X-ray-sensitive material are positioned on an assembly support.

[0007] Document DE 10 2014 221 829 A1 discloses a method for producing a sensor plate of a detector module, wherein a plurality of readout units are provided which are each positioned on a common sensor layer in a stacked structure.

[0008] Document DE 10354497A1 describes a detector for an X-ray tomography device, wherein a detector module is abutted against an adjustment plate on a beam input side, wherein a first adjustment component arranged on the detector module on the beam input side engages with a second adjustment component corresponding to the first adjustment component and arranged on the adjustment plate to accurately position the detector module. Summary of the invention

[0009] Therefore, the technical problem to be solved by the present invention is to improve imaging by means of and / or to produce a detector module of a CT system.

[0010] The technical problem is solved according to the invention by a method for positioning a sensor unit in a detector module of a CT system, the method comprising at least the following steps:

[0011] - arranging the connecting layer on the positioning substrate,

[0012] - positioning at least one sensor unit and preferably at least one reader unit relative to the positioning substrate to form a sensor reader, wherein the sensor unit is temporarily connected to the positioning substrate in a fixed position by means of the connecting layer,

[0013] - preferably positioning at least one electronic circuit board and establishing a conductive connection between said electronic circuit board and contacts of a reading unit in order to obtain at least one sensor circuit board,

[0014] - Positioning the sensor unit and preferably the sensor circuit board relative to the module carrier with the aid of the positioning substrate, and placing the sensor unit on the module carrier to obtain a detector module, wherein the positioning substrate has optical markings and the positioning of the at least one sensor unit and, if necessary, the at least one reading unit relative to the positioning substrate is achieved in an image processing-controlled manner.

[0015] This object is achieved according to the invention by a detector module for a CT system, which is obtained by a method of the aforementioned type.

[0016] This object is achieved according to the invention by the use of a positioning substrate for positioning a sensor unit relative to a module carrier of a detector module of a CT system, wherein:

[0017] - positioning at least one sensor unit relative to the positioning substrate and temporarily connecting the at least one sensor unit to the positioning substrate in a fixed position by means of a connecting layer, and

[0018] - positioning the sensor unit relative to the module carrier and attaching it to the module carrier by means of the positioning substrate to obtain a detector module,

[0019] - and wherein the positioning substrate has optical markings and the positioning of the at least one sensor unit relative to the positioning substrate is achieved in an image processing controlled manner.

[0020] The aforementioned method for positioning a sensor unit in a detector module of a CT device comprises at least the following steps. In a first step, a connecting layer is arranged on a positioning substrate. In another step, a plurality of sensor units, preferably a plurality of reading units, are positioned relative to the positioning substrate to form a sensor reading device. The sensor reading device here respectively comprises a sensor unit and a plurality of reading units with contacts. The sensor unit is temporarily connected to the positioning substrate in a fixed position by means of a connecting layer. In another step, preferably, a plurality of electronic circuit boards are positioned, in particular relative to the positioning substrate. In addition, a plurality of conductive connections are preferably established between the electronic circuit board and the contacts of the reading unit. It is further preferred that a plurality of sensor circuit boards or sensor boards are thereby obtained. In addition, the sensor unit and preferably the sensor circuit board are positioned relative to the module carrier by means of the positioning substrate and are placed on the module carrier. A detector module is thereby obtained.

[0021] The positioning substrate is a planar, in particular flat substrate, whose surface has particularly small deviations in a direction perpendicular to the substrate surface or substrate plane. The positioning substrate can be made, for example, of silicon, steel, glass or a suitable material with similarly favorable surface properties. The positioning substrate serves as an auxiliary component for positioning the sensor unit relative to the module carrier.

[0022] The sensor cell usually comprises a semiconductor material, for example CdTe, CdZnTe, CdZnTeSe, CdTeSe, CdMnTe, InP, TlBr2, HgI2. Therefore, the sensor cell is designed in particular as a direct conversion sensor cell. That is, when a voltage is applied, the sensor cell converts incident photons of a suitable wavelength into an electrical signal.

[0023] The connecting layer provides a temporary connection between the sensor unit and the positioning substrate during the manufacturing process and is fixed relative to the positioning substrate. The connecting layer can be designed, for example, in the form of an adhesive film, a paint, a tape or the like. The connecting layer can include, for example, a suitable polymer. Other characteristics of the connecting layer will be described in detail below.

[0024] "Temporary" here means that the connection can be released in another step of the manufacturing process without damaging or destroying the sensor unit and the positioning substrate. This ensures that the sensor unit can be used normally in the detector. On the other hand, it also allows the positioning substrate to be reused in another manufacturing process. However, for a new manufacturing process, a new connection layer can be applied to the positioning substrate if necessary.

[0025] “Fixed in position” means here that the sensor unit has neither translational nor rotational degrees of freedom relative to the positioning substrate. In other words, the temporary connection between the positioning substrate and the sensor unit is rigid.

[0026] The term "several or at least one" means that the corresponding feature is included at least once; however, the feature may also be included multiple times. In contrast, the term "multiple" means that the corresponding feature is included more than once in each case.

[0027] The sensor reading device has a sensor unit and several reading units. That is, the sensor reading device includes a sensor unit and one or more reading units, which read and, if necessary, analyze the electrical signal generated by the incident photons in the sensor material. The sensor reading arrangement is particularly designed here so that it detects and preferably counts the electrical signal of a single incident photon. To this end, a conductive contact is formed pixel by pixel between the reading unit and the corresponding sensor unit, and the contact preferably simultaneously realizes a mechanically rigid connection. As mentioned above, these contacts can be established, for example, by means of solder in a reflow soldering process, and the solder is introduced between two components in a ball array. The contacts can alternatively also be established, for example, by means of a pixel-by-pixel and conductive bonding. The reading unit can be designed, for example, as an integrated circuit, in particular an ASIC. In general, it particularly relates to a photon counting sensor reading device.

[0028] Furthermore, in order to establish the contact between the electronic circuit board and the reader unit, one of the electrically conductive and preferably mechanically rigid connection methods already described above is used. The electronic circuit board serves for further processing and transmission of the measurement data detected by the sensor unit or the sensor reader. The electronic circuit board can be designed, for example, as a typical circuit board with corresponding printed circuits and other electronic components. The combination of an electronic circuit board with several sensor readers or a mechanically and electronically integrated structure is referred to as a sensor circuit board or sensor board.

[0029] The module carrier serves as a stable holding device, which is accurately positioned in the detector. The module carrier is made of cast aluminum or similar materials, for example. The module carrier has precise mechanical connection elements or similar elements for connecting to the detector. The sensor circuit board is arranged on the module carrier or connected to the module carrier. This can be achieved, for example, by a mechanical connection formed by a suitable bonding process or similar process. The combined structure of the module carrier and the sensor board is called a detector module. The module carrier is used to mechanically rigidly connect the sensor circuit board to other components of the detector.

[0030] The detector module is used in a CT device. In principle, the CT device can be any common CT device in the art. However, the CT device particularly includes a detector for directly converting photon counting as described above. A plurality of detector modules are usually installed in a column section of the CT device, which is basically opposite to the X-ray source. The positioning of the detector module during installation is usually achieved by a mechanical positioning device commonly used in the art.

[0031] In contrast to known production methods, the positioning accuracy of the sensor unit relative to the module carrier no longer depends on the positioning accuracy of other layers on the sensor unit, such as the reading unit, the electronic circuit board, the intermediate layer (rewiring layer), etc. Instead, the positioning accuracy of the individual sensor units now depends only on the positioning accuracy relative to the positioning substrate and the positioning accuracy of the positioning substrate relative to the module carrier.

[0032] Even if other intermediate layers, in particular the reader unit and the electronic circuit board, are preferably also positioned relative to the positioning substrate, inaccuracies in these optional process steps do not affect the positioning accuracy of the sensor unit relative to the module carrier. This means that even inaccuracies that may occur during the individual reflow soldering process steps when the component "floats" have no effect on the positioning accuracy of the sensor unit relative to the module carrier.

[0033] Therefore, the above-mentioned detector module for a CT device can be obtained or manufactured by the above-mentioned method for positioning a sensor unit in a detector module according to the present invention.

[0034] As mentioned above, the positioning substrate is used to position the sensor unit relative to the module carrier of the detector module of the CT device. At least one sensor unit is positioned relative to the positioning substrate and is temporarily connected to the positioning substrate in a fixed position by means of a connecting layer. Then, the sensor unit is positioned relative to the module carrier by means of the positioning substrate and is mounted on the module carrier to obtain the detector module.

[0035] Other particularly advantageous designs and extensions of the invention are apparent from the following description, wherein claims of one claim type may also be extended similarly to claims of another claim type and to parts of the description, and in particular individual features of different embodiments or variant designs may be combined into new embodiments or variants.

[0036] The deviations or height differences of the surfaces of the positioning substrate are preferably less than 15 μm, particularly preferably less than 10 μm, particularly preferably less than 5 μm.

[0037] According to the invention, the positioning substrate has an optical mark, and the positioning of the at least one sensor unit and, if necessary, the at least one reading unit or at least one sensor reading device relative to the positioning substrate (20) is achieved in an image processing controlled manner. Alternatively or additionally, the positioning substrate preferably has an optical mark, and the positioning of the at least one sensor circuit board relative to the module carrier is achieved in an image processing controlled manner. With the aid of the optical mark, the sensor unit or the reading unit or the sensor reading device and / or the sensor circuit board can advantageously be positioned accurately relative to the positioning substrate or the module carrier. For this purpose, for example, a camera is used, and the positioning is regulated in a control loop (feedback loop) taking into account the detected image. The positioning accuracy controlled by image processing is preferably better than 15 μm, particularly preferably better than 10 μm, and particularly preferably better than 5 μm in a direction parallel to the surface of the positioning substrate. The electronic circuit board is also preferably positioned relative to the positioning substrate with the aid of the optical mark.

[0038] Preferably, the positioning substrate has a first mechanical positioning element, which is used to position at the second mechanical positioning element of the module carrier. The positioning element is designed in particular as a defined shape feature. This means that the positioning elements interact in a form-fitting manner, in particular directly or via additional elements, such as fixing pins, so that the positioning substrate can be positioned with high precision relative to the module carrier. The first mechanical positioning element is particularly preferably designed as a hole in the positioning substrate.

[0039] The second positioning element is also particularly preferably designed as a hole. However, the positioning element is also preferably designed so that it is also suitable as a connecting device connected to a corresponding module holding device of the detector. The positioning element can be designed, for example, as a thread connected to the detector thread.

[0040] The holes of the first positioning element and the second positioning element can have the same clear inner diameter. The first positioning element and the second positioning element can be aligned with each other, for example, so as to be positioned by means of a fixing pin or a positioning pin. The fixing pins can here each fit into the hole with very small tolerances. Alternatively, the fixing pins can also have, for example, conical sections, which serve to self-center the holes relative to each other. Overall, the sensor is thus positioned relative to the module carrier with a positioning accuracy of substantially 20 μm by means of the method according to the invention.

[0041] In a first preferred variant, the positioning of the at least one sensor unit and the at least one reading unit comprises at least the following sub-steps:

[0042] - positioning at least one sensor unit relative to the positioning substrate and temporarily connecting the at least one sensor unit to the positioning substrate in a fixed position by means of the connecting layer,

[0043] - At least one reading unit is respectively positioned relative to the positioning substrate and conductively connected to a sensor unit respectively connected to the positioning substrate to obtain at least one sensor reading device.

[0044] In other words, in this first variant, the sensor unit is first positioned separately on the positioning substrate, and only then the reading unit is positioned and connected to the sensor unit. In this variant, the positioning element of the positioning substrate can be used to accurately position the reading unit relative to the positioning substrate if necessary.

[0045] In a second preferred variant, the positioning of the at least one sensor unit and the at least one reading unit comprises at least the following sub-steps:

[0046] At least one reader unit is positioned relative to one another and is respectively conductively connected to a sensor unit to produce at least one sensor reader.

[0047] - positioning the at least one, in particular a plurality of, sensor readers relative to the positioning substrate, wherein the sensor unit of the at least one sensor reader is temporarily connected to the positioning substrate in a positionally fixed manner by means of the connecting layer.

[0048] In other words, in this first variant, the sensor unit is first positioned relative to the reading unit and connected to the reading unit. The combined sensor reader, in particular the sensor of the sensor reader, is then positioned relative to the positioning substrate. This variant has the advantage that the sensor reader can be prefabricated. However, the positioning accuracy of the sensor unit relative to the positioning substrate is not reduced in this case compared to the other variants.

[0049] Preferably, the electronic circuit board is designed as a flexible electronic circuit board, a reinforced flexible electronic circuit board, a solid-flexible-solid electronic circuit board or a solid electronic circuit board. These circuit boards are particularly suitable for CT equipment or its detector. In the design of the detector, the choice of the circuit board depends on the requirements for its stability, flexibility, thickness or similar mechanical properties or properties that are beneficial to electrical conduction.

[0050] Preferably, the positioning substrate is made of silicon, steel or particularly preferably of glass. All these materials have only very slight deviations or height differences as described above on their surfaces when suitably prepared. The use of glass provides the special advantage that the optical positioning elements for positioning in an image processing controlled manner can also be detected through the substrate by a camera or similar device. In other words, the positioning substrate is preferably transparent to optical radiation. This makes positioning in an image processing controlled manner easier.

[0051] The connecting layer preferably has thermal, optical, chemical and / or mechanical release properties or corresponding release mechanisms.

[0052] For the thermal release property, the connection layer is cooled to below a specified temperature or heated to above a specified temperature in order to achieve release from the sensor unit or to facilitate such release. For this purpose, it is preferred that essentially only the positioning substrate and the connection layer are heated or cooled, but not other components that are still connected to the positioning substrate. The specified temperature is selected here so that, on the one hand, the melting point of the solder is not reached, for example, at the welding point, and at the same time no components are damaged. However, temperature effects, in particular local temperature effects, can, for example, make the connection layer brittle, liquefy, etc. In any case, the adhesion between the sensor unit and the connection layer is weakened due to the temperature effect.

[0053] For the optical release property, the connecting layer is irradiated with light of a defined wavelength in order to reduce the adhesion of the sensor unit to the connecting layer. This is, for example, radiation in the ultraviolet range (UV radiation) or the like.

[0054] For the chemical release property, the connecting layer is immersed in a solvent provided for the connecting layer, for example. This dissolves the connecting layer. This also causes the sensor unit to be released from the connecting layer or the positioning substrate. The solvent is selected so that the remaining components are not damaged.

[0055] For the mechanical release behavior, for example, normal stress, bending stress, shear stress and / or torsion stress are generated in the connection layer by applying corresponding forces, so that the connection breaks or tears off the sensor unit. The connection layer is designed in this case so that the sensor unit and other components are not damaged during the breaking or tearing.

[0056] After the sensor circuit board has been positioned on the board module carrier, the connecting layer and the positioning substrate are preferably released from the sensor unit. The positioning substrate is an auxiliary device for positioning the sensor unit and is not or is not necessarily a component of the manufactured detector module. Therefore, the positioning substrate is preferably removed after the sensor unit has been positioned relative to the module carrier. For this purpose, one or more of the aforementioned release properties of the connecting layer are preferably used. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The invention is explained in more detail below using embodiments with reference to the drawings. Identical components in different drawings are provided with the same reference numerals. If not otherwise specified, relative positional conditions and / or directional conditions, such as "upper", refer to the direction perpendicular to the positioning substrate on the side with the connecting layer. The drawings are generally not true to scale. In the drawings:

[0058] Figure 1 A schematic perspective view showing initial components and products of process step I of an embodiment of a method for positioning a sensor unit according to the present invention,

[0059] Figure 2 Shown as Figure 1 The illustration shown, however, is for method step II and alternative method step II′.

[0060] Figure 3 Shown as Figure 1 The illustration shown, however, is for method step III,

[0061] Figure 4 Shown as Figure 1 The illustration shown, however, is for method step IV, and

[0062] Figure 5 Shown as Figure 1 The illustration shown, however, refers to method step V. DETAILED DESCRIPTION

[0063] Figures 1 to 5 The process steps of the method according to the invention for positioning a sensor unit in a detector module of a CT system as well as the initial components and the production of the sensor unit are shown by way of example and schematically in a perspective view. Figure 1 Here, step I of the method is shown.

[0064] In step I, a positioning substrate 20 is provided. The positioning substrate 20 is essentially planar and has a rectangular base surface made of glass. The positioning substrate 20 has a smooth surface with a deviation of up to 5 μm. The positioning substrate is along the direction z with its longitudinal direction (indicated here by the central axis). When installed in the CT device, the direction z corresponds to the direction of the cranio-caudal axis of the patient (not shown here) on the patient couch in the CT device. In addition, a direction phi perpendicular to the z direction is shown, which corresponds to the circumference of a circle around the cranio-caudal axis of the patient when installed in the CT device. The direction phi corresponds to the lateral direction of the positioning substrate 20.

[0065] The positioning substrate 20 has a thickness perpendicular to the z direction and the phi direction, and the thickness is selected so that the positioning substrate has sufficient mechanical properties for positioning, such as breaking strength, bending strength, etc.

[0066] The positioning substrate 20 has a hole 22 in each of its two end regions in the longitudinal direction, centrally relative to the transverse direction of the positioning substrate, which hole has a defined radius. The hole 22 serves as a first mechanical positioning element 22 .

[0067] Furthermore, the positioning substrate 20 has optical markings 23 in the form of positioning crosses. The optical markings 23 are arranged in groups of four. The optical markings 23 in groups of four are each positioned in the corners of a rectangle, wherein the rectangles are arranged equidistantly in the direction z and are arranged centrally relative to the center axis of the positioning substrate 20 in the direction phi. The distance between adjacent rectangles is in this case of the order of magnitude of the pixels of the sensor unit 24 (see Figure 2 ) and is preferably smaller than one pixel.

[0068] In step I, a connecting layer 21 is applied to the positioning substrate 20, which connecting layer consists, for example, of a polymer film, which cures after a certain period of time and in the next step II, the sensor unit 24 to be positioned is temporarily connected to the positioning substrate 20. For the temporary design of the connection, the connecting layer 21 has optical release properties, for example. This means that after the curing of the connecting layer, the connection to the sensor unit 24 can be released again by the action of radiation in the UV spectrum, in that the polymer bonds formed during the curing process are destroyed by the UV radiation.

[0069] Figure 2Step II is shown, in which the sensor unit 24 is positioned relative to the positioning substrate 20. Positioning is achieved here in an image processing controlled manner. The position of the corresponding sensor unit 24 and the position of the correspondingly assigned four groups of optical marks 23 are detected here by at least one camera. The optical mark 23 indicates the end position of the corner of the relevant sensor unit 24. By automatically comparing the position of the optical mark 23 with the position of the corner of the sensor unit 24, a positioning device, such as a robot arm, can be controlled in a feedback loop so that the robot arm positions the sensor unit 24 as accurately as possible. The deviation or tolerance when positioning in an image processing controlled manner is preferably less than 15μm, particularly preferably less than 10μm, and particularly preferably less than 5μm. The individual pixels of the sensor unit 24 are respectively displayed here as a grid on the sensor unit 24.

[0070] After all sensor units 24 have been positioned, connecting layer 21 is cured in order to form a temporary, positionally fixed, ie, mechanically rigid connection between sensor units 24 and positioning substrate 20 .

[0071] In addition, Figure 2 , an alternative step II' is shown. A prefabricated sensor reader 26, which includes a sensor unit 24 and a reader unit 25, is positioned on the positioning substrate 20 in an image processing-controlled manner as described above. The sensor reader 26 is prefabricated by introducing solder between the two components in a ball array (not shown here) and connecting the two components to each other in an electrically conductive and mechanically rigid manner after a reflow soldering process. Here, an electrically conductive contact is formed pixel by pixel between the reader unit 25 and the sensor unit 24 by means of the individual solder balls of the ball array. In various variant designs, the sensor reader 26 can also include multiple reader units 25 for each sensor unit 24.

[0072] After step II, if after positioning the sensor unit 24 on the positioning substrate 20 (and optionally curing the connecting layer), at least one reading unit 25 is positioned on the sensor unit 24 as already described in the context of step II' and connected by means of ball array and reflow soldering, the same product is obtained as after carrying out step II'. The positioning of the reading unit 25 can be carried out in an image processing-controlled manner and relative to the positioning substrate 20 or its optical markings 23 as already described. The sensor reading device 26 is also generated by the sensor unit 24 and the reading unit 25.

[0073] exist Figure 3In the embodiment, four sensor readers 26 arranged together with the positioning substrate are connected to the electronic circuit board 32. This is also achieved as basically described above by means of a ball array 33 and a reflow soldering process. In the reflow soldering process, it is preferred to work with relatively low temperatures and a solder material suitable for this purpose in order not to impair the electrical contact in the sensor reader 26.

[0074] The electronic circuit board 32 comprises a flexible substrate 30, on which a reinforcement element 31 is arranged in the region that is to contact the sensor reading device 26. This serves to achieve additional mechanical stabilization. The electronic circuit board 32 also has several electronic components 35, by which the measurement data detected by means of the sensor unit 24 and read by means of the reading unit 25 are further processed and transmitted. For the transmission, the electronic circuit board 32 has electrical contacts 34, which are connected to the detector or other components of the CT device in order to finally realize the reconstruction of the CT image from the measurement data.

[0075] The connection or combination resulting from the sensor reader 26 and the electronic circuit board 32 in this manner is referred to as a sensor circuit board 36 or sensor board 36 .

[0076] Figure 4 Process step IV is shown, in which the sensor circuit board 36 is positioned relative to the module carrier 40 by means of the positioning substrate 20. For this purpose, the positioning pins or fixing pins are passed through the holes 22 in the positioning substrate 20 or through the first mechanical positioning elements 22 (see Figures 1 to 3 ) and inserted through corresponding holes 41 in the module carrier 40 or through second mechanical positioning elements 41. By manufacturing the corresponding positioning elements 22, 40 and positioning pins as accurately as possible with low tolerances, preferably in a self-centering manner, a positioning accuracy of less than 10 μm, preferably less than 5 μm, of the sensor unit 24 relative to the module carrier 40 can be achieved overall. This represents a clear improvement over the manufacturing methods known from practice.

[0077] The sensor circuit board 36 is arranged on the module carrier 40 and is mechanically rigidly connected or joined to the module carrier. This can be achieved, for example, by mechanical form-fitting and / or friction-fitting connecting devices. Alternatively or additionally, the sensor circuit 36 ​​can be bonded to the module carrier 40 by using a suitable material. The connection or combination of the sensor circuit board 36 and the module carrier 40 is referred to as a detector module 42. However, the detector module 42 can also include other components as described below.

[0078] exist Figure 5, step V is shown, in which the positioning substrate 20 and the connecting layer 21 are released from the sensor unit. After the sensor circuit board 36 is firmly connected to the module carrier 40, the positioning pins are first removed from the mechanical positioning elements 22, 41. The connecting layer 21 is then irradiated with UV light in accordance with its optical release properties until it is released from the sensor unit.

[0079] After removal from the positioning substrate 20 and the connecting layer 21, the other components of the detector module 42 can be placed on the now free side of the sensor unit 26. A high-voltage film 50 is shown here by way of example, which is in electrical contact with the sensor unit 26. The high-voltage film provides a suitable bias voltage for the sensor unit 26 during operation. In addition, a so-called anti-scatter grid 51 or anti-scatter grid (ASG) is arranged on the high-frequency film to protect the sensor unit 26 from obliquely incident beams during operation.

[0080] The described exemplary embodiment of the method according to the invention thus results in a detector module 42 having a high positioning accuracy relative to the sensor unit 26 of the module carrier 40. Due to the mechanically precise production of the mechanical connecting elements 22, 41 and the precise positioning of the first mechanical connecting element 22 relative to the second mechanical connecting element 41, a high positioning accuracy of the sensor unit 26 relative to the detector can also be achieved overall.

[0081] As mentioned above, since the image quality that can be achieved by a CT device with increasingly higher resolution, i.e., increasingly smaller pixels, depends decisively on the precise positioning of the pixels or the sensor units including the pixels, the present invention also helps to improve the image quality as a whole, in particular the image quality of CT devices with direct conversion of photon counts, and also simplifies its manufacturing process.

[0082] Finally, it should be reiterated that the devices and methods described in detail above are only embodiments, and those skilled in the art can optimize the embodiments in different ways, as long as they do not leave the scope of the present invention. In addition, the use of the indefinite article "a" or "an" does not exclude that the relevant features may also exist in multiple. Similarly, the terms "device", "unit", "circuit board", "device" or "module" do not exclude that they are composed of multiple components, which may also be distributed in space if necessary, unless otherwise specified.

Claims

1. A method for positioning a sensor unit (24) in a detector module (42) of a CT device, the method comprising at least the following steps: - arranging the connecting layer (21) on the positioning substrate (20), - positioning at least one sensor unit (24) and at least one reader unit (25) relative to the positioning substrate (20) to form a sensor reader device (26), wherein the sensor unit (24) is temporarily connected to the positioning substrate (20) in a fixed position by means of the connecting layer (21), - positioning at least one electronic circuit board (32) and establishing a conductive connection between said electronic circuit board (32) and contacts of a reading unit (25) in order to obtain at least one sensor circuit board (36), - Positioning the sensor unit (24) relative to the module carrier (40) with the aid of the positioning substrate (20) and placing the sensor unit (24) on the module carrier (40) to obtain a detector module (42), wherein the positioning substrate (20) has an optical mark (23) and the positioning of the at least one sensor unit (24) relative to the positioning substrate (20) is achieved in an image processing-controlled manner.

2. The method according to claim 1, wherein: The sensor circuit board (36) is positioned relative to the module carrier (40) by means of the positioning substrate (20).

3. The method according to claim 1, wherein: The positioning of the at least one reading unit (25) relative to the positioning substrate (20) is achieved in an image processing controlled manner.

4. The method according to claim 1, wherein: The at least one sensor circuit board (36) is positioned relative to the module carrier (40) in an image processing-controlled manner.

5. The method according to claim 1, wherein: The positioning substrate (20) has a first mechanical positioning element (22) for positioning at a second mechanical positioning element (41) of the module carrier (40).

6. The method according to any one of claims 1 to 5, wherein: The positioning of the at least one sensor unit (24) and the at least one reading unit (25) comprises at least the following sub-steps: - positioning at least one sensor unit (24) relative to the positioning substrate (20) and temporarily connecting the at least one sensor unit to the positioning substrate (20) in a fixed position by means of the connecting layer (21), - at least one reading unit (25) is positioned relative to the positioning substrate (20) and conductively connected to the sensor unit (24) respectively connected to the positioning substrate (20) to obtain at least one sensor reading device (26).

7. The method according to any one of claims 1 to 5, wherein: The positioning of the at least one sensor unit (24) and the at least one reading unit (25) comprises at least the following sub-steps: - positioning at least one reading unit (25) relative to one another and connecting each to a sensor unit (24) in a conductive manner to obtain at least one sensor reading device (26), - Positioning the at least one sensor reader (26) relative to the positioning substrate (20), wherein the sensor unit (24) of the at least one sensor reader (26) is temporarily connected to the positioning substrate (20) in a fixed position by means of the connecting layer (21).

8. The method according to claim 1, wherein: The electronic circuit board (32) is designed as a flexible electronic circuit board, a reinforced flexible electronic circuit board (32), a solid-flexible-solid electronic circuit board or a solid electronic circuit board.

9. The method according to claim 1, wherein: The positioning substrate (20) is made of silicon or steel.

10. The method according to claim 1, wherein: The positioning substrate (20) is made of glass.

11. The method according to claim 1, wherein: The connecting layer (21) has thermal, optical, chemical and / or mechanical release properties.

12. The method according to claim 1, wherein: The positioning substrate (20) is transparent to optical radiation.

13. The method according to claim 1, wherein: After the sensor printed circuit board (36) has been positioned on the module carrier (40), the connecting layer (21) and the positioning substrate (20) are released from the sensor unit (24).

14. A detector module (42) for a CT device, the detector module being obtained by the method according to any one of claims 1 to 13.

15. A use of a positioning substrate (20) for positioning a sensor unit (24) relative to a module carrier (40) of a detector module (42) of a CT device, wherein: - positioning at least one sensor unit (24) relative to the positioning substrate (20) and temporarily connecting the at least one sensor unit to the positioning substrate (20) in a fixed position by means of a connecting layer (21), and - positioning the sensor unit (24) relative to the module carrier (40) and attaching it to the module carrier (40) by means of the positioning substrate (20) to obtain a detector module (42), - and wherein the positioning substrate (20) has optical markings (23), and the positioning of the at least one sensor unit (24) relative to the positioning substrate (20) is achieved in an image processing controlled manner.

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