Ultrasound probe

Abstract

The present description relates to an ultrasound probe (200) comprising: - an interconnection substrate (230); - an array of ultrasound transducers (201); - an integrated control circuit (202) electrically connected to the array of ultrasound transducers and positioned on a first face (230A) of the interconnection substrate; - a capacitive structure (210) positioned at a second face (230B) of the interconnection substrate opposite the first face, the capacitive structure having a mechanically rigid insulating substrate, comprising at least one dielectric layer, and two metal elements insulated from one another and positioned on either side of each dielectric layer, forming at least one capacitance.

Description

B23662PCT - CATH-ICE-CAPARAID 1 DESCRIPTION TITLE: Ultra sound probe This application is based on, and claims priority from, French patent application FR2414202 filed on December 16, 2024, entitled "Ultrasonic Probe", which is considered to be an integral part of this description within the limits provided by law. technical field

[0001] This description generally relates to ultrasonic probes comprising ultrasonic transducers, transducer control circuits, and generally passive electronic components.

[0002] This description may relate, in particular, to ultrasonic probes integrated into catheters, which may be referred to as ultrasound catheters. Previous technique

[0003] It has already been proposed to integrate a small ultrasound probe into a catheter, which can then be called an ultrasound catheter. The ultrasound catheter can be intended to be introduced into a patient's body, for example into a blood vessel, particularly to perform imaging of an anatomical region.

[0004] Ultrasound catheters have been designed for use in many anatomical regions, for example, for diagnostic, therapeutic, drug delivery, and / or surgical purposes. Among the known techniques are intravascular ultrasound (IVUS) and intracardiac echocardiography (ICE). In both techniques, the ultrasound probe typically includes a B23662PCT- CATH-ICE-CAPARAID 2 An array of ultrasonic transducers, or ultrasound transducer array, is positioned at one end of the catheter to emit ultrasonic waves. This end is generally referred to as the distal end of the catheter, through which the catheter is guided into the area of ​​the body to be examined. The transducers can then be used to receive ultrasound waves reflected back from specific structures within the anatomical region. The reflected ultrasound waves can be transmitted to a processing device designed to process them and produce an image of the body area where the catheter is placed. The generated image is either a plane or a volume. Alternatively, the generated image can be one or more radiofrequency lines for measurement purposes, such as for Doppler and elastography modalities.

[0005] An IVUS catheter is typically used in a blood vessel, such as a vein, or in a respiratory system, such as the bronchi, and is usually associated with a guidewire that has a flexible tip to guide the catheter into the vessel. An ICE catheter is typically used in a region of the heart, or even a surrounding structure, to image that region, for example, to prepare for, guide, and / or facilitate medical procedures. An ICE catheter is not usually designed to be associated with a guidewire, but rather typically includes a distal end that can be articulated by a guiding mechanism located in a handle at a proximal end of the catheter.

[0006] In addition to IVUS and ICE applications, other applications of transesophageal echocardiography (TEE) can be mentioned. B23662PCT - CATH-ICE-CAPARAID 3 Echocardiography), laparoscopy, and endocardial exploration, including 4D with electronics.

[0007] The ultrasound probe typically includes a control circuit mounted near the transducer array. A control circuit can select individual transducer elements, or groups of transducer elements, to transmit ultrasound waves and / or receive ultrasound waves reflected by the tissues to be imaged or characterized.

[0008] To improve their performance, an increasing number of ultrasonic probes incorporate integrated circuits, particularly for control circuits. An integrated circuit is, for example, an application-specific integrated circuit, known by the acronym ASIC (Application Specific Integrated Circuit). Integrated circuits can improve the signal-to-noise ratio of ultrasonic probes, significantly increase the number of channels in the transducer array, and / or provide reconfiguration capabilities.

[0009] Furthermore, it is generally necessary to add power reservoirs, commonly called decoupling capacitors, to integrated circuits to prevent, or minimize, voltage fluctuations under all operating conditions, particularly transient conditions and the current consumption profile of the ultrasonic probe. Power reservoirs typically consist of capacitors, for example, surface-mounted (SMD) components. Capacitors may be part of a set of passive electronic components, which may include other electronic components. B23662PCT - CATH-ICE-CAPARAID

[0010] To maximize efficiency, capacitors are preferably located as close as possible to the integrated circuits. Furthermore, the size of a capacitor is generally directly related to the average power and transient operating profile it can handle, ideally remaining below a maximum voltage, or even a maximum temperature. As the number of transducers in the array increases, it may be necessary to increase the size of the capacitors, which can significantly impact their footprint within the ultrasonic probe, or even call into question the feasibility of integrating these capacitors into the probe.

[0011] Indeed, since the ultrasound probe is generally intended to be introduced, with the catheter, into an anatomical space of small cross-section or small diameter, its external diameter is typically a few millimeters, for example an external diameter of 5 mm (15 French), or even less than or equal to 1.6 mm (5 French) for ICE applications, or 1 mm (3 French) for IVUS applications.

[0012] It can be difficult to manufacture an ultrasonic probe that integrates, in addition to ultrasonic transducers, integrated circuits and electronic components such as capacitors within a diameter of just a few millimeters. In other words, it can be challenging to create an ultrasonic probe with a small external diameter, typically just a few millimeters, while still integrating ultrasonic transducers, integrated circuits, electronic components such as capacitors, and the various electrical interconnections within that same ultrasonic probe. B23662PCT- CATH-ICE-CAPARAID 5

[0013] It would be desirable to have an ultrasonic probe that at least partially overcomes some of the drawbacks of known ultrasonic probes.

[0014] In particular, there is a need for an ultrasound probe, for example an ultrasound probe intended to be integrated into a catheter, that can integrate several electronic functionalities associated with the ultrasound transducer array, including control integrated circuits and passive electronic components such as capacitors, in a reduced diameter, while maintaining efficient assembly, interconnection and operation of the ultrasound probe. Summary of the invention

[0015] One embodiment overcomes all or part of the disadvantages of known ultrasonic probes.

[0016] One embodiment provides for an ultrasonic probe comprising: - an interconnection substrate; - an array of ultrasonic transducers; - an integrated control circuit electrically connected to the ultrasonic transducer network and positioned on one face of the interconnection substrate; - a capacitive structure positioned on a second face of the interconnecting substrate opposite the first face, the capacitive structure comprising a mechanically rigid insulating substrate, including at least one dielectric layer, and two metallic elements insulated from each other and positioned on either side of each dielectric layer, forming at least one capacitance.

[0017] The capacitive structure thus fulfills the functions of capacitance and mechanical rigidity of the ultrasonic probe. B23662PCT-CATH-ICE-CAPARAID 6

[0018] The transducer network has a first length, the control integrated circuit has a second length, and the capacitive structure has a third length.

[0019] According to one embodiment, the third length is greater than or equal to the second length.

[0020] According to one embodiment, the second length is greater than or equal to the first length.

[0021] According to one embodiment, the interconnecting substrate comprises a first portion and a second portion facing the first portion, said first and second portions being for example connected by a third portion forming a fold of the interconnecting substrate, the capacitive structure being positioned between said first portion and said second portion.

[0022] According to one embodiment, the ultrasonic transducer network is positioned on the control integrated circuit.

[0023] According to one embodiment, the control integrated circuit is between the ultrasonic transducer network and the capacitive structure.

[0024] According to one embodiment, the ultrasonic transducer network is positioned on a first portion of the interconnection substrate, and the control integrated circuit is positioned on a second portion of the interconnection substrate distinct from the first portion.

[0025] According to one embodiment, the ultrasonic transducer network is positioned on the first face of the interconnecting substrate.

[0026] According to one embodiment, the capacitive structure is between the ultrasonic transducer network and the control integrated circuit. B23662PCT- CATH-ICE-CAPARAID 7

[0027] According to one embodiment, each dielectric layer of the insulating substrate is a ceramic layer or a ceramic sheet.

[0028] According to one embodiment, the insulating substrate is a stack of several layers or sheets of ceramic, the metallic elements being positioned on either side of each layer or sheet of ceramic.

[0029] According to one embodiment, the capacitive structure comprises, for example, a stack of co-fired metallized ceramic sheets, for example at low temperature.

[0030] According to one embodiment, ceramics: - has a relative permittivity greater than 300; and / or - is non-piezoelectric; and / or - is paraelectric or ferroelectric.

[0031] According to one embodiment, the insulating substrate of the capacitive structure comprises, for example, a glass.

[0032] According to one embodiment, the insulating substrate of the capacitive structure comprises silicon, preferably oxidized to form a layer of dielectric material around the silicon.

[0033] According to one embodiment, the capacitive structure comprises a metallic structure which includes the metallic elements, the metallic structure being structured so as to form with the insulating substrate a plurality of capacitive elements.

[0034] According to one embodiment, the capacitive elements are individually connected and / or interconnected in series and / or interconnected in parallel, via the interconnecting substrate, so as to configure several capacitance values ​​in the capacitive structure. B23662PCT- CATH-ICE-CAPARAID 8 Brief description of the drawings

[0035] These features and advantages, as well as others, will be described in detail in the following description of particular embodiments, given by way of non-limiting example, in relation to the attached figures, among which:

[0036] Figure 1A is a three-dimensional view representing an example of an ultrasonic probe;

[0037] Figure 1B is a side view of the ultrasonic probe in Figure 1A;

[0038] Figure 1C is a top view of the ultrasonic probe in Figure 1A;

[0039] Figure 1D is a three-dimensional view representing an example of a capacitor that can be integrated into the ultrasonic probe of Figures 1A to 1C;

[0040] Figure 1E is a three-dimensional view representing another example of a capacitor that can be integrated into the ultrasonic probe of Figures 1A to 1C;

[0041] Figure 2A is a three-dimensional view representing an ultrasonic probe according to one embodiment;

[0042] Figure 2B is a side view of the ultrasonic probe in Figure 2A;

[0043] Figure 2C is a top view of the ultrasonic probe in Figure 2A;

[0044] Figure 3A is a top view representing an example of an embodiment of a capacitive structure of an ultrasonic probe according to one embodiment;

[0045] Figure 3B is a three-dimensional view of the capacitive structure of Figure 3A; B23662PCT- CATH-ICE-CAPARAID 9

[0046] Figure 3C and Figure 3D are top and three-dimensional views representing an example of assembly and electrical connection of the capacitive structure of Figures 3A and 3B to the interconnecting substrate of Figures 2A to 2C;

[0047] Figure 4 is a top view representing another example of an embodiment of a capacitive structure of an ultrasonic probe;

[0048] Figure 5A is a partial three-dimensional view representing an ultrasonic probe according to another embodiment;

[0049] Figure 5B is a side view of the ultrasonic probe in Figure 5A;

[0050] Figure 5C is a bottom view of the ultrasonic probe in Figure 5A; and

[0051] Figure 5D is a top view of the ultrasonic probe in Figure 5A. Description of the implementation methods

[0052] The same elements have been designated by the same reference numerals in the different figures. In particular, structural and / or functional elements common to the different embodiments may have the same reference numerals and may have identical structural, dimensional and material properties.

[0053] For the sake of clarity, only the steps and elements necessary for understanding the described embodiments have been shown and detailed. In particular, the ultrasonic transducers of the described ultrasonic probes have not been detailed, as the described embodiments are compatible with all or most known ultrasonic transducer structures. Furthermore, the circuits B23662PCT - CATH-ICE-CAPARAID 10 The ultrasonic probe control integrated circuits described have not been detailed, as the described embodiments are compatible with all or most of the usual control integrated circuits for ultrasonic transducers.

[0054] Unless otherwise specified, when referring to two elements connected together, this means directly connected without intermediate elements other than conductors, and when referring to two elements coupled together, this means that these two elements can be connected or linked through one or more other elements.

[0055] Unless otherwise specified, when referring to two elements mounted, or positioned, one on top of the other, this does not necessarily mean that these two elements are mounted, or positioned, directly on top of each other; one or more other elements may be positioned between these two elements.

[0056] In the description that follows, when referring to absolute position qualifiers, such as the terms "front", "back", "up", "down", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "superior", "inferior", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., unless otherwise specified, reference is made to the orientation of the figures or to an ultrasonic probe in a normal operating position.

[0057] Unless otherwise specified, the expressions "approximately", "roughly", "about", and "on the order of" mean to within 10% or 10°, preferably to within 5% or 5°.

[0058] In the following description, when referring to a longitudinal direction, it refers to B23662PCT - CATH-ICE-CAPARAID 11 to a direction parallel to the axis of the ultrasonic probe. The longitudinal direction corresponds to the X direction shown in the figures. A transverse direction corresponds to a direction taken in a plane transverse to the longitudinal direction. The figures illustrate two transverse directions, Y and Z.

[0059] In the following description, when referring to a transducer, unless otherwise specified, it refers to an ultrasonic transducer, and when referring to a probe, unless otherwise specified, it refers to an ultrasonic probe. Furthermore, when referring to a control integrated circuit, or control circuit, the term "control" should be understood in a general sense, encompassing both the sending of signals, particularly for controlling electronic components, and the reception of signals that it can process. The terms "control circuit" or "control integrated circuit" may also be used.

[0060] In the following description, when referring to a catheter, it is broadly defined as a thin, usually flexible, hollow or solid rod-shaped device intended for insertion into a region of a human or animal body (e.g., a cavity, a lumen, or a duct), typically for the purpose of injecting fluid and / or draining its contents. An ultrasound catheter is defined as a catheter equipped with an ultrasound probe, typically intended for imaging a region of a human or animal body.

[0061] In the following description, a distal end corresponds to an end through which an ultrasound probe, or catheter, is introduced into a medium to be analyzed, and a proximal end corresponds to an end B23662PCT - CATH-ICE-CAPARAID 12 opposite to the distal end. The proximal end generally corresponds to an electrical connection end, or wiring, of the ultrasound probe, respectively of the catheter.

[0062] Figure 1A is a three-dimensional view representing an example of an ultrasonic probe 100. Figure 1B is a side view of the ultrasonic probe 100 from Figure IA. Figure 1C is a top view of the ultrasonic probe 100 from Figure IA.

[0063] The 100 ultrasound probe is intended to be integrated into a catheter, at the distal end of the catheter, to form an ultrasound catheter.

[0064] The ultrasonic probe 100 comprises an array of ultrasonic transducers 101 arranged on a control integrated circuit 102 in a vertically integrated configuration. The control integrated circuit 102 may be an application-specific integrated circuit, known as an ASIC (Application Specific Integrated Circuit). The control integrated circuit 102 is disposed on a flexible interconnect substrate 103. An upper portion 103A of the interconnect substrate 103 is disposed on an elongated parallelepiped-shaped stiffener 104. The interconnect substrate 103 is folded under the stiffener 104. In other words, the stiffener 104 is positioned between the upper portion 103A of the interconnect substrate 103 and a lower portion 103B of the interconnect substrate 103.

[0065] The stiffener 104 provides mechanical support and secures / mounts ultrasonic transducers, for example, to ensure flatness and proper positioning. The stiffener 104 can also provide rigidity to the ultrasonic probe 100. The stiffener 104 generally lacks electrical connection functions. B23662PCT- CATH-ICE-CAPARAID 13 which are filled in particular by the interconnecting substrate 103. To ensure good mechanical strength and / or good rigidity, the stiffener 104 is preferably solid, that is to say not entirely hollow.

[0066] The ultrasonic probe 100 comprises two modules 105 of electronic components, which are positioned on either side of the stiffener 104, and of the stack formed by the transducer network 101 and the control integrated circuit 102.

[0067] The modules 105 are wrapped by the interconnect substrate 103, which can ensure an interconnection between the modules 105 and the control integrated circuit 102. More specifically, the modules 105 are wrapped by the upper portion 103A of the interconnect substrate 103, the lower portion 103B of the interconnect substrate 103, and transverse portions 103C, 103D which can connect the upper and lower portions.

[0068] For example, one of the modules 105 is located at a first end 100A of the ultrasound probe 100, which may correspond to a distal end, and is wrapped at the fold of the interconnecting substrate 103, between the upper portion 103A, the lower portion 103B, and a first transverse portion 103C connecting the upper and lower portions at this first end. Another of the modules 105 is located at a second end 100B of the ultrasound probe 100, which may correspond to a proximal end, and is wrapped between the upper portion 103A, the lower portion 103B, and a second transverse portion 103D that corresponds to an extension of the upper portion 103A joining the lower portion 103B at this second end. However, it can be envisaged that the upper portion 103A and the lower portion 103B do not B23662PCT- CATH-ICE-CAPARAID 14 do not join in the second end 100B, and that there is no second transverse portion 103D.

[0069] The 105 modules include passive electronic components, in particular capacitors, forming power reservoirs for the control integrated circuit 102. Each 105 module may include several capacitors, typically in the form of surface-mount components (SMD), and the capacitors in this module may have several capacitance values, for example, ranging from 10nF to 1µF.

[0070] The 105 modules of electronic components can be capacitive modules or include other passive electronic components, for example inductors and / or resistors.

[0071] To manage hundreds of ultrasonic transducers in the transducer array 101 while minimizing voltage fluctuations, the control integrated circuit 102, such as an ASIC, may require numerous capacitors, perhaps with different capacitance values. Consequently, the modules 105 can be quite large, for example, forming parallelepipeds with length / width / height dimensions ranging from 0.6 mm / 0.3 mm / 0.3 mm to 3.5 mm / 3 mm / 3 mm. Considering their integration within a probe of small outer diameter, the configuration shown in Figures 1A to 1C allows such parallelepiped modules 105 to be positioned as close as possible to the control integrated circuit 102, while ensuring their interconnection via the interconnect substrate 103.

[0072] Figure 1D is a three-dimensional view showing an example of a 150 capacitor that can be integrated into the ultrasonic probe shown in Figures 1A to 1C. Figure 1E is a three-dimensional view showing a B23662PCT - CATH-ICE-CAPARAID 15 Another example of a 150' capacitor that can be integrated into the ultrasonic probe in Figures 1A to 1C. The capacitors in Figures 1D and 1E can make up module 105 in Figures 1A to 1C.

[0073] As shown in Figures 1D and 1E, capacitors 150, 150' are multilayer structures comprising several layers 151, for example, between 1 and 10 layers, of ferroelectric material. The ferromagnetic material is ceramic, with average relative permittivities between 600 and 6000. The layers 151 are electrically connected in parallel to each other, either by through-conducting vias or by lateral conductive elements 152 arranged around the layers 151, as shown in Figures 1D and 1E. A structure of these conductive elements 152, which takes the form of grooves 153 in the examples shown, allows precise control of the surface area over which each capacitance is expressed. The conductive elements can be referred to as "electrodes". Such capacitors are suitable for operation at high voltage, typically between 20V and 100V.

[0074] Figure 1D shows a capacitor 150 comprising four layers 151 of ferroelectric material, each 0.7 mm thick. The multilayer structure, with the conductive elements 152, forms a parallelepiped with a length of 3.2 mm, a width of 2.5 mm, and a thickness (height) of 2.8 mm. The capacitance of this capacitor 150 is, for example, approximately 1 µF.

[0075] Figure 1E shows a capacitor 150' comprising 6 layers 151 of ferroelectric material, each having a thickness of 0.08 mm, the multilayer structure with the conducting elements 152 forming a parallelepiped of length 1 mm, width 0.5 mm and thickness (height) 0.5 B23662PCT- CATH-ICE-CAPARAID 16 mm. The capacitance of this 150' capacitor is, for example, equal to approximately 1µF.

[0076] All these elements 101, 102, 103, 104, 105 of the ultrasonic probe 100 are integrated inside a sheath made of an acoustically transparent material, or having at least a portion made of an acoustically transparent material opposite the transducer array 101. The sheath being intended to be in contact with the tissues of the anatomical region into which the catheter is introduced, it is preferably biocompatible.

[0077] Because the 100 ultrasound probe is designed to be inserted, along with the catheter, into a small anatomical space, the external diameter of both the ultrasound probe and the sheath is generally a few millimeters, for example, an external diameter of 5 mm (15 French) or less, or even 3 mm (9 French), or 1.6 mm (5 French) or less for ICE applications, or 1 mm (3 French) for IVUS applications. The internal diameter of the ultrasound probe varies depending on the sheath wall thickness and can be 4.5 mm or less, or even 1 mm or 0.7 mm.

[0078] Thus, in the configuration shown in Figures 1A to 1C, it can be seen that the modules 105 already occupy a significant volume, and that this volume can hardly be increased within a constrained internal diameter. Conversely, it may be necessary to reduce the volume occupied by the modules 105 in order to reduce the size of the ultrasonic probe 100.

[0079] There is a need for an ultrasound probe, for example, an ultrasound probe intended for integration into a catheter, that can integrate a control integrated circuit and passive electronic components such as capacitors, all within a small diameter, while B23662PCT- CATH-ICE-CAPARAID 17 now an efficient assembly, interconnection and operation of the ultrasonic probe.

[0080] Figure 2A is a three-dimensional view of an ultrasonic probe 200 according to one embodiment. Figure 2B is a side view of the ultrasonic probe 200 of Figure 2A. Figure 2C is a top view of the ultrasonic probe of Figure 2A.

[0081] Similar to the ultrasonic probe 100 of Figures 1A to 1C, the ultrasonic probe 200 of Figures 2A to 2C includes a transducer array 201, or acoustic component, comprising ultrasonic transducers adapted to emit and receive ultrasonic waves.

[0082] All or part of the ultrasonic waves emitted by the transducers of the transducer array 201 may be reflected by specific features of the medium into which the ultrasonic probe 200 is introduced, for example, specific features of a region of a vessel, a heart, or more generally, of a structure surrounding the ultrasonic probe. The reflected ultrasonic waves may be received by the transducers. These reflected ultrasonic waves may be processed by a processing device to produce an image of the medium in which the ultrasonic probe is placed, for example, to visualize specific features. The processing device may be located in all or part of the control integrated circuits 202 described later.

[0083] An ultrasonic transducer is a transducer designed to convert an electrical signal into an ultrasonic wave, and conversely, to convert an ultrasonic wave into an electrical signal. Depending on the type of transducer, the electrical signal can be a voltage, a current, or an electrical charge. B23662PCT - CATH-ICE-CAPARAID 18

[0084] The 201 transducer network can include any type of ultrasonic transducer, or even several types of ultrasonic transducers.

[0085] Ultrasonic transducers can consist of a single-crystal or polycrystalline piezoelectric layer, such as PZT (lead zirconia titanate), or a composite structure comprising at least one piezoelectric layer, for example, a PZT layer with polymer-filled grooves. The resting thickness of the piezoelectric layer can range from 0.05 to 1 mm, and this thickness varies when a voltage is applied. The thickness of an ultrasonic transducer, including electrodes and other layers, can range from 0.1 to 2 mm.

[0086] Ultrasonic transducers can be microelectromechanical systems (MEMS), employing microelectronic manufacturing technologies. A MEMS transducer typically consists of a deformable membrane suspended above a cavity. In one embodiment, the deformable membrane is displaced or deformed by capacitive force using an electrode attached to the membrane and a separate electrode separated by the cavity. This type of ultrasonic transducer is known by the acronym CMUT, for Capacitive Micromachined Ultrasonic Transducer, also called a micromachined capacitive ultrasonic transducer or membrane capacitive transducer. According to another embodiment, the deformable membrane is displaced or deformed by piezoelectric effect using a layer of piezoelectric material equipped with two electrodes attached to the membrane.This type of ultrasonic transducer is known by the acronym PMUT, from the English Piezoelectric. B23662PCT- CATH-ICE-CAPARAID 19 Micro-machined Ultrasonic Transducer, that is to say a micro-machined piezoelectric ultrasonic transducer, or piezoelectric membrane transducer.

[0087] The 201 transducer array can include any number of ultrasonic transducers, for example between 50 and 400 transducers aligned along the longitudinal X direction. The 201 transducer array can be a matrix consisting of several dozen rows and columns, i.e. several hundred or even thousands of transducers, for example a matrix of 12x64 transducers, i.e. 768 transducers.

[0088] The transducer array 201 has a length L1 and a width 11. The length and width L1 and 11 depend on the number of transducers and the array spacing. The array spacing itself depends on the center frequency of the ultrasonic signals. For example, the length L1 is between 10 and 20 mm, for example, approximately 15 mm, and the width 11 is between 0.5 and 4 mm, for example, approximately 2 mm.

[0089] Similar to the ultrasonic probe 100 of Figures 1A to 1C, the ultrasonic probe 200 of Figures 2A to 2C further includes a control integrated circuit 202, or control circuit 202. The control integrated circuit 202 may be an application-specific integrated circuit, or ASIC, or any other integrated circuit suitable for controlling several ultrasonic transducers.

[0090] The control integrated circuit 202 is, for example, configured to control all the transducers in the transducer array 201. The control integrated circuit 202 can include several electronic circuits enabling it to perform different functions; these electronic circuits can be grouped into several B23662PCT- CATH-ICE-CAPARAID 20 cells, each associated with one or more transducers of the transducer network 201.

[0091] The control integrated circuit 202 can be configured to select certain transducers from the transducer array 201 for use in transmitting / receiving ultrasonic waves, to transmit control signals to the selected transducers so that they generate and transmit ultrasonic waves, and / or to accept or even amplify return signals from the selected transducers when they receive reflected ultrasonic waves, or even to perform operations on the return signals, such as beamforming and / or scanning. More generally, several types of signals, such as control, power, and / or data signals, can be exchanged between the transducers in the transducer array 201 and the control integrated circuit 202.

[0092] The control integrated circuit 202 has a length L2 and a width 12. For example, the length L2 is between 15 and 30 mm, for example approximately 20 mm, and the width 12 is between 1 and 4 mm, for example approximately 2 mm. Preferably, the length L2 is greater than the length L1 to allow access to contact pads on the control integrated circuit 202, for example, digital control, synchronization, power supply pads, and other signals related to the transmission and reception phases of ultrasonic waves.

[0093] In the example shown in Figures 2A to 2C, similarly to Figures 1A to 1C, the transducer network 201 is connected to the control circuit 202, according to a so-called vertical integration, but this is not limiting, as shown in the variant in Figures 4A to 4D described later. For example, the electrical connections between the transducer network B23662PCT - CATH-ICE-CAPARAID 21 201 and the control circuit 202 are made using solder balls or using an anisotropic conductive film.

[0094] Similar to the ultrasonic probe 100 of Figures 1A to 1C, the ultrasonic probe 200 of Figures 2A to 2C comprises an interconnecting substrate 230 on which the control integrated circuit 202 is disposed. The control integrated circuit 202 is disposed on an upper portion 231 of the interconnecting substrate 230, and on a first face 230A, or outer face, of the interconnecting substrate 230. The interconnecting substrate 230 is folded (folded portion 233) at a first end 200A of the ultrasonic probe 200, which may be a distal end, to form a lower portion 232 below the upper portion 231. The lower portion 232 extends to a second end 200B of the ultrasonic probe 200, which may be a proximal end. The fold portion 233 of the interconnecting substrate 230 connects the upper portion 231 and lower portion 232.

[0095] The 230 interconnect substrate is preferably flexible enough to be folded as described above. The 230 interconnect substrate can be a flexible printed circuit board (FPCB). To minimize stress in the 230 interconnect substrate, the folding areas should ideally have a minimum bend radius of a few micrometers.

[0096] In the example shown in Figures 2A to 2C, the upper and lower portions 231 and 232 of the interconnecting substrate 230 meet at the second end 200B. However, it is possible that the upper 231 and lower 232 portions of the interconnecting substrate 230 do not meet at the second end 200B. In all cases, the upper and lower portions 231 and 232 of the interconnecting substrate 230 can form B23662PCT - CATH-ICE-CAPARAID 11 connecting tabs, blades, strips, or flats at the second end 200B. The connecting flats can be used to couple the interconnect substrate 230 to circuits, cables, connectors and / or components external or internal to the ultrasonic probe 200. Other configurations can be considered by a person skilled in the art.

[0097] The ultrasonic probe 200 of Figures 2A to 2C differs from the ultrasonic probe 100 of Figures 1A to 1C in that it does not include the modules 105 on either side of the stiffener 104, and the stack formed by the network of transducers 101 and the control integrated circuit 102, but it includes a capacitive structure 210 positioned between the upper portion 231 and the lower portion 232 of the interconnecting substrate 230, replacing the stiffener 104.

[0098] The capacitive structure 210 is connected to a second face 230B, or inner face, of the interconnecting substrate 230, opposite to the first face 230A, in each of the upper portion 231 and lower portion 232.

[0099] The capacitive structure 210 fulfills at least the functions of a power reservoir for the control integrated circuit 202, i.e., it provides capacitance, and of mechanical rigidity for the ultrasonic probe 200, acting as a mechanical stiffener. This may include a mechanical holding function, or even a fixing / mounting function, for the ultrasonic transducers.

[0100] The capacitive structure 210 can have a shape adapted to fit into the space between the upper portion 231 and the lower portion 232 of the interconnecting substrate 230. The form factor of the capacitive structure can be optimized, its size reduced, and its positioning within the ultrasonic probe optimized, for example, to reduce the size of the ultrasonic probe and / or B23662PCT - CATH-ICE-CAPARAID 23 to increase the electrical capacity of this capacitive structure. For example, the capacitive structure 210 is roughly parallelepiped in shape.

[0101] As shown in Figures 2A and 2B, the capacitive structure 210 replaces the stiffener 104 shown in Figures 1A to 1C, without the need to add the modules 105, which have a considerable size. This allows for a reduction in the height of the ultrasonic probe, and potentially its length as well. Alternatively, for an equivalent ultrasonic probe length, this allows for an increase in the length of the control integrated circuit and / or the transducer array. More broadly, this optimizes the arrangement of the various components of the ultrasonic probe, thereby minimizing their overall size within the probe.

[0102] The capacitive structure 210 has a length L3 and a width l3. For example, the length L3 is between 18 and 40 mm, for example approximately 22 mm, and the width l3 is between 0.3 and 4.5 mm, for example approximately 2 mm. Preferably, the length L3 is greater than or equal to the length L2 of the control integrated circuit 202. For example, the length L3 is also greater than or equal to the length L1 of the transducer array 201. The fact that the length L3 of the capacitive structure 210 is greater than or equal to the length L1 of the transducer array 201 and / or the length L2 of the control integrated circuit 202 has the technical effect of stiffening the ultrasonic probe 200 over a significant portion of its length, thereby ensuring or even increasing the mechanical rigidity effect conferred by the capacitive structure.

[0103] To fulfill the functions of capacitance and mechanical stiffness, the capacitive structure 210 may include an insulating substrate made of a dielectric material, or comprising B23662PCT- CATH-ICE-CAPARAID 24 A dielectric material with a relative permittivity of epsilon, for example greater than 1 or greater than 1.3, is used as the insulating substrate. The substrate is covered with inter-insulated metallic elements forming electrodes, for example, on each of its upper and lower faces. The insulating substrate provides mechanical rigidity to the capacitive structure, while the metal / dielectric / metal stack forms at least one capacitor. The insulating substrate can be a multilayer structure, in which case metallic elements are also positioned between the layers of the insulating substrate.

[0104] The capacitive structure 210 can be implemented in different ways. Three embodiments of capacitive structures are described below, although a person skilled in the art may consider variations of these embodiments, or even other embodiments.

[0105] According to a first embodiment, the capacitive structure comprises a ceramic substrate, for example, a ceramic layer or a stack of ceramic layers. The ceramic preferably has a high permittivity or a high dielectric constant, typically with a relative permittivity (or dielectric constant) between 300 and 18,000. The ceramic is preferably non-piezoelectric. The ceramic may be paraelectric or ferroelectric, with or without dopants. The ceramic substrate may be a bulk ceramic.

[0106] Examples of ceramics include: barium titanate, for example in percentages ranging from 10% to 98% of the ceramic composition, for example with rare-earth additives (neodymium, samarium), oxides, for example titanium oxide, and dopants. Examples of ceramics may include other formulations of B23662PCT- CATH-ICE-CAPARAID 25 ceramics such as calcium titanate, calcium zirconate, magnesium titanate, strontium titanate...

[0107] To form the capacitive structure, a conductive structure, for example metallic, can be formed around the ceramic substrate, for example on each of the top and bottom faces, or even between the ceramic layers in the case of a stack of several ceramic layers. The metallic structure can be structured to form isolated metallic elements, or electrodes, on either side of each ceramic layer. The metallic structure can also be structured to form, with the ceramic substrate, several individual capacitive elements, each equipped with electrodes.

[0108] The insulating substrate, for example the ceramic substrate, is preferably chosen to provide significant mechanical stiffness, for example with a Young's modulus greater than 100 GPa, or even greater than 200 GPa.

[0109] The capacitance of the capacitive structure can be determined by the ceramic used, its dielectric constant, the dimensions (length, width, and thickness) of the ceramic substrate, the characteristics of the metallic structure, and, as described later, the number of capacitive elements and their electrical connection. The dimensions of the ceramic substrate can also influence the stiffness of the capacitive structure.

[0110] The metal structure can be produced mechanically, or by dry engraving, or by laser engraving, or by any other structuring technique.

[0111] The metal structure can be produced using an additive manufacturing technique. B23662PCT – CATH-ICE-CAPARAID 26

[0112] An example of the realization of this first embodiment is illustrated in figures 3A and 3B.

[0113] Figure 3A is a top view representing an example of an embodiment of a capacitive structure 300 of an ultrasonic probe. Figure 3B is a partial three-dimensional view of the capacitive structure 300 of Figure 3A.

[0114] In the example of Figures 3A and 3B, the capacitive structure 300 comprises a stacking 310 of four layers of ceramic 311, but this number of layers of ceramic 311 is not limiting, the number of layers of ceramic 311 can vary, for example be between 1 and 100. The thickness of each layer of ceramic 311 can be between 0.02 and 2 mm, for example be about 0.2 mm.

[0115] The ceramic layers 311 are embedded in a metal structure 320. The metal structure 320 includes a metal envelope 321 which surrounds the stack 310 of the ceramic layers 311 and intercalated metal layers 322 which are positioned between the ceramic layers 311, and which are in contact with the metal envelope 321.

[0116] The metal structure 320 is structured by cutting patterns allowing access to the stack 310 of ceramic layers 311.

[0117] In the example of Figures 3A and 3B, the cutting patterns include longitudinal grooves 323 extending in the X direction: a longitudinal groove 323A is formed in the metal casing 321 on the upper face 310A of the stack 310, a longitudinal groove 323B is formed in the metal casing 321 on the lower face 310B of the stack 310, and grooves B23662PCT – CATH-ICE-CAPARAID 27 Longitudinal grooves 323C are formed in each metal layer 322 interposed between the ceramic layers 311. Preferably, as shown in Figure 3B, two successive longitudinal grooves are offset from each other in the Y direction. These longitudinal grooves 323 allow the formation, for each ceramic layer 311, of two upper electrodes 325 insulated from each other, and two lower electrodes 326 insulated from each other. The electrodes located to the right of the grooves 323 are connected to each other by the right side of the metal casing 321. The electrodes located to the left of the grooves 323 are connected to each other by the left side of the metal casing 321.The metallic structure 320 thus structured makes it possible to form for each layer of ceramic 311 a capacity on the metal / ceramic / metal stacking areas which are between the grooves 323 and to put the capacities thus created in parallel, while making two terminal links (upper and lower faces of the metallic envelope 321) appear on each face of the stack 310.

[0118] Each electrode can typically have a thickness between 0.1 and 50 µm.

[0119] In the example shown in Figures 3A and 3B, the cutting patterns further include transverse grooves 324 all around the stack 310, in both the Y and Z directions. In the Y direction, the grooves 324 extend inward from each of the two lateral faces of the capacitive structure 300 until they reach the nearest longitudinal groove 323B, 323C. This allows the internal electrodes to be separated from the sides to create the individual capacitances. These transverse grooves 324 allow for the formation of several capacitive elements 301 along the X direction. In the example shown in Figures 3A and 3B, there are 25 capacitive elements B23662PCT - CATH-ICE-CAPARAID 28 301 are formed along the X direction by these transverse grooves 324.

[0120] The metal in the 320 metallic structure includes, for example, gold, copper, and / or nickel. This 320 metallic structure can be produced by physical vapor deposition (PVD), chemical vapor deposition (CVD), or chemical deposition.

[0121] The assembly of the ceramic layers 311 with the metallic layers 322 together can be carried out by bonding, co-sintering, aerosol, or tape casting.

[0122] These details of the metal structure 320 are given by way of non-limiting example; other types of metal structures, and for example other cutting patterns, may be considered by a person skilled in the art. For example, instead of having lower and upper electrodes, a person skilled in the art may consider having interdigitated electrodes arranged on the same face of each ceramic layer 311.

[0123] The capacitive structure 300 can form the capacitive structure 210 of figures 2A to 2C, or of figures 5A to 5D described later.

[0124] As a non-limiting example, the capacitive structure 300 has a length of approximately 18 mm and a width of approximately 2 mm.

[0125] It is possible to use, and connect, all or part of the capacitive elements 301 individually, and / or to connect all or part of the capacitive elements 301 together, in series and / or in parallel, for example to control the capacitance value of the capacitive structure 300. B23662PCT- CATH-ICE-CAPARAID 29

[0126] For example, with a ceramic having a relative permittivity of 3000, a capacitance of 1 µF can be obtained for each capacitive element 301. If all these capacitive elements 301 are connected in parallel in the same electrical circuit, the capacitive structure 300 can be considered a single capacitor of approximately 25 µF. If all these capacitive elements 301 are connected in series, the capacitive structure 300 can be considered a single capacitor of approximately 40 nF. Therefore, all combinations are possible for connecting the capacitive elements 301 together and / or individually to obtain different capacitance values.

[0127] The interconnection of the various capacitive elements 301 is generally achieved via an interconnection substrate, for example the interconnection substrate 230 of Figures 2A to 2C. The interconnection substrate can thus make the electrical connections of the capacitive elements in series, in parallel and / or individually, so as to configure several capacitance values ​​in the capacitive structure 300. The interconnection substrate 230 also allows the resulting capacitances to be connected to the control integrated circuit 202 or to an equipotential, for example ground or a reference potential of a supply voltage.

[0128] Figure 3C and Figure 3D are top and three-dimensional views representing an example of assembly and electrical connection of the capacitive structure 300 of Figures 3A and 3B to the interconnecting substrate 230 of Figures 2A to 2C.

[0129] Figures 3C and 3D illustrate three types of electrical connections: a cell 302 of three capacitive elements 301 connected in parallel, a cell 303 of three capacitive elements 301 connected in series, and several elements B23662PCT- CATH-ICE-CAPARAID 30 301 capacitive elements connected individually. Three approximately 1 µF capacitive elements connected in parallel form a capacitance of 3 µF, while three 1 µF capacitive elements connected in series form a capacitance of approximately 0.33 µF.

[0130] The assembly and electrical connections to the interconnecting substrate are made in this example via the lower electrodes 326 which are positioned on the lower face 310B of the stack 310.

[0131] The first embodiment allows for obtaining several capacitance values ​​within the same capacitive structure by adapting the metallic structure, in particular by adapting the patterns, forming several unitary capacitive elements, and by organizing the interconnection of these capacitive elements. One way to configure different capacitance values ​​in the capacitive structure is to arrange the interconnections in series and / or in parallel between the different capacitive elements, and / or to connect some of these capacitive elements individually via the interconnecting substrate.

[0132] According to a second embodiment, the capacitive structure can be fabricated using microelectronic technologies. This type of structure is known as an IPD, for "Integrated Passive Device." The capacitive structure can comprise a glass, quartz, or silicon-based substrate, instead of a bulk ceramic substrate. The silicon-based substrate is preferably oxidized to form at least one insulating dielectric layer (silicon oxide) on each of its top and bottom faces, or around the substrate. A metallic structure can be fabricated by a deposition technique on the substrate, for example, by PVD or CVD, and then the metallic structure can be patterned into cutting patterns to form several B23662PCT - CATH-ICE-CAPARAID 31 electrodes on the substrate. The capacitive structure may include an encapsulation layer, for example, with low permittivity to encapsulate the metallized insulating substrate. This encapsulation layer can be achieved by anodic bonding for a glass-based substrate, or by another bonding technique, for example, wafer bonding, for a silicon-based substrate. The interconnection can be formed by etching techniques to expose the electrodes to be connected.

[0133] A glass or silicon-based substrate can provide more rigidity to the capacitive structure, compared to a solid ceramic substrate. In addition, IPD technology makes it possible to obtain other types of passive components such as inductors or resistors.

[0134] According to a third embodiment, the capacitive structure may comprise metallized ceramic sheets stacked one on top of the other, the stack being sintered using the LTCC (Low Temperature Co-fired Ceramic) technique. The metallization of the ceramic sheets may be carried out in such a way as to form interdigitated electrodes between the ceramic sheets.

[0135] A capacitive structure of the LTCC type can provide much more rigidity, compared to a solid ceramic substrate.

[0136] Figure 4 is a top view representing another embodiment of a capacitive structure for an ultrasonic probe. This other embodiment corresponds to the third embodiment of the capacitive structure.

[0137] The capacitive structure 400 comprises a stack 410 of several ceramic sheets 411, in this example seven B23662PCT- CATH-ICE-CAPARAID 32 ceramic sheets, but this number is not limited, the number of 411 ceramic sheets can vary, for example be between 1 and 100. The thickness of each 411 ceramic sheet can be between 20 µm and 1 mm.

[0138] The capacitive structure 400 further comprises, on either side of each ceramic sheet 411, a pair of upper electrodes 425 and lower electrodes 426. The upper electrodes 425 and lower electrodes 426 are part of a metallic structure 420 which further comprises a chain of vias 427 for connecting the upper electrodes 425 to each other, and a chain of vias 428 for connecting the lower electrodes 426 to each other. Grooves 423 are formed in the metallic structure 420 so as to isolate the upper electrodes 425 from the lower electrodes 426, and the chain of vias 427 from the chain of vias 428.

[0139] The metal structure 420, thus structured, allows for the formation of a capacity on the area of ​​the metal / ceramic / metal stacks which is located between the grooves 423.

[0140] The capacitive structure 400 can form the capacitive structure 210 of figures 2A to 2C, or of figures 5A to 5D described later.

[0141] The embodiment shown in Figures 2A to 2C is particularly advantageous for acoustic components that do not require acoustic attenuating material on the rear face of the transducers. Indeed, the ultrasonic waves on the rear face of the transducers in array 201 can be reflected by the control circuit 202 and interfere with the electrical signal generated by the waves received by the transducers on the front face.

[0142] Figure 5A is a three-dimensional view representing a 500 ultrasonic probe according to another mode of B23662PCT- CATH-ICE-CAPARAID 33 Implementation. Figure 5B is a side view of the 500 ultrasonic probe from Figure 5A. Figure 5C is a bottom view of the 500 ultrasonic probe from Figure 5A. Figure 5D is a top view of the 500 ultrasonic probe from Figure 5A.

[0143] The ultrasonic probe 500 of Figures 5A to 5D differs from the ultrasonic probe 200 of Figures 2A to 2C primarily in that the transducer array 201 is not positioned on the control integrated circuit 202, but on the interconnect substrate 230. The transducer array 201 is arranged on the upper portion 231 of the interconnect substrate 230, and on the first face 230A, or outer face, of the interconnect substrate 230. The control integrated circuit 202 is positioned on the lower portion 232 of the interconnect substrate 230, and on the first face 230A of the interconnect substrate 230.

[0144] This integration is called horizontal, referring to an integration of the transducer network 201 and the control integrated circuit 202 on the interconnection substrate 230 when the latter is not folded.

[0145] This type of integration allows, for example, better thermal management of the ultrasonic probe. Indeed, the heat exchange surface area with the outside of the ultrasonic probe is increased since it is made up of both the external surface of the transducer array 201 and the external surface of the control circuit 202. On the other hand, the capacitive structure 210 interposed between the transducer array 201 and the control circuit 202 also serves as a thermal drain.

[0146] The positioning of the capacitive structure 210 is similar to that of Figures 2A to 2C, i.e., between the upper portion 231 and the lower portion 232 of the interconnecting substrate 230, the capacitive structure 210 B23662PCT- CATH-ICE-CAPARAID 34 being connected to the second face 230B, or inner face, of the interconnecting substrate 230, and this in each of the upper portion 231 and lower portion 232.

[0147] The other characteristics of the ultrasonic probe 200 described in connection with figures 2A to 2C can be applied to the ultrasonic probe 500 of figures 5A to 5D.

[0148] The examples of implementation described show that the capacitive structure according to the embodiments allows for the realization of other form factors compared to capacitive modules such as the 105 modules described in connection with figures 1A to 1C, while finding the same capacitance values, or even increasing them, or adapting them as needed.

[0149] For each of the examples and embodiments described above, and more generally for any capacitive structure in any embodiment, an insulating layer may be provided on the electrodes of the capacitive structure, at least on the faces of the capacitive structure that are exposed to the interconnecting substrate, to prevent any short circuit with this interconnecting substrate. Alternatively, the insulating layer may be provided on each face of the interconnecting substrate that is exposed to the capacitive structure.

[0150] The ultrasound probe, depending on the embodiment, can find applications in the field of intracardiac echocardiography (ICE), or in the field of intravascular ultrasound imaging (IVUS), or even in the field of high-intensity ultrasound therapy (HIFU), the ultrasound probe being integrated into a catheter, or even in the field of transesophageal echocardiography (TEE), laparoscopy, and endocavitary exploration. B23662PCT- CATH-ICE-CAPARAID 35

[0151] Various embodiments and variations have been described. A person skilled in the art will understand that some features of these various embodiments and variations could be combined, and other variations will become apparent to a person skilled in the art.

[0152] Finally, the practical implementation of the described methods and variants is within the reach of the person in the trade, based on the functional indications given above.

Claims

B23662PCT- CATH-ICE-CAPARAID 36 DEMANDS 1. Ultrasonic probe (200; 500) comprising: - an interconnection substrate (230); - an array of ultrasonic transducers (201); - an integrated control circuit (202) electrically connected to the ultrasonic transducer network and positioned on a first face (230A) of the interconnecting substrate; - a capacitive structure (210; 300; 400) positioned on a second face (230B) of the interconnecting substrate opposite the first face, the capacitive structure comprising a mechanically rigid insulating substrate (310, 410), including at least one dielectric layer (311; 411), and two metallic elements (325, 326; 425, 426) insulated from each other and positioned on either side of each dielectric layer, forming at least one capacitor (301; 401); the capacitive structure thus fulfilling the functions of capacitor and mechanical rigidity of the ultrasonic probe.

2. Ultrasonic probe (200; 500) according to claim 1, wherein the ultrasonic transducer array has a first length (L1), the control integrated circuit has a second length (L2), and the capacitive structure has a third length (L3): - the third length being greater than or equal to the second length; and / or the second length being greater than or equal to the first length.

3. Ultrasonic probe (200; 500) according to claim 1 or 2, wherein the interconnecting substrate (230) comprises a first portion (231) and a second portion (232) facing the first portion, said first and second portions being, for example, connected by a third portion (233) forming a fold of the substrate B23662PCT - CATH-ICE-CAPARAID 37 d interconnection, the capacitive structure ( 210 ) being positioned between said first portion and said second portion.

4. Ultrasonic probe (200) according to any one of claims 1 to 3, wherein the ultrasonic transducer array (201) is positioned on the control integrated circuit (202).

5. Ultrasonic probe (200) according to claim 4, wherein the control integrated circuit (202) is between the ultrasonic transducer array (201) and the capacitive structure (210).

6. Ultrasonic probe (500) according to any one of claims 1 to 3, wherein the ultrasonic transducer array (201) is positioned on a first portion (231) of the interconnecting substrate (230), and the control integrated circuit (202) is positioned on a second portion (232) of the interconnecting substrate (230) distinct from the first portion.

7. Ultrasonic probe (500) according to claim 6, wherein the ultrasonic transducer array (201) is positioned on the first face (230A) of the interconnecting substrate (230).

8. Ultrasonic probe (500) according to claim 6 or 7, wherein the capacitive structure (210) is between the ultrasonic transducer array (201) and the control integrated circuit (202).

9. Ultrasonic probe according to any one of claims 1 to 8, wherein each dielectric layer (311, 411) of the insulating substrate (310, 410) is a ceramic layer or a ceramic foil. B23662PCT - CATH-ICE-CAPARAID 38 10. Ultrasonic probe according to claim 9, wherein the insulating substrate (310; 410) is a stack of several layers or sheets of ceramic (311, 411), the metallic elements (325, 326; 425, 426) being positioned on either side of each layer or sheet of ceramic.

11. Ultrasonic probe according to claim 9 or 10, wherein the capacitive structure (400) comprises, for example, a stack of co-fired metallized ceramic sheets (411), for example at low temperature.

12. Ultrasonic probe according to any one of claims 9 to 11, wherein the ceramic: - has a relative permittivity greater than 300; and / or - is non-piezoelectric; and / or - is paraelectric or ferroelectric.

13. Ultrasonic probe according to any one of claims 1 to 8, wherein the insulating substrate of the capacitive structure comprises, for example, a glass.

14. Ultrasonic probe according to any one of claims 1 to 8, wherein the insulating substrate of the capacitive structure comprises silicon, preferably oxidized to form a layer of dielectric material around the silicon.

15. Ultrasonic probe according to any one of claims 1 to 14, wherein the capacitive structure (300; 400) comprises a metallic structure (320, 420) which includes the metallic elements (325, 326; 425, 426), the metallic structure being structured so as to form with the insulating substrate (310, 410) a plurality of capacitive elements (301; 401); for example B23662PCT-CATH-ICE-CAPARAID 39 the capacitive elements (301; 401) are connected individually and / or interconnected in series and / or interconnected in parallel, via the interconnecting substrate (230), so as to configure several capacitance values ​​in the capacitive structure (300;

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