Ultrasound Imaging Devices

Abstract

The present specification relates to an ultrasonic imaging device (100) comprising an ultrasonic transducer assembly (101) and an acoustic coupling layer (140) covering the ultrasonic transducer assembly (101), the acoustic coupling layer (140) being formed of an activatable polymer material configured to have a first Young's modulus during an ultrasonic image acquisition phase and a second Young's modulus greater than the first Young's modulus outside the acquisition phase.

Description

[Technical field]

[0001] The present disclosure relates to the field of ultrasound imaging devices, and more particularly to ultrasound transducer-based skin pattern acquisition and / or microvascular imaging devices. [Background technology]

[0002] An ultrasound imaging device conventionally comprises a number of ultrasound transducers and an electronic control circuit connected to the ultrasound transducers. In operation, the ultrasound transducers are all positioned in front of the object or body whose image is to be acquired. The electronic control circuit is configured to apply an electrical excitation signal to the ultrasound transducers, causing the ultrasound transducers to emit ultrasound waves towards the body to be analyzed. The ultrasound waves emitted by the ultrasound transducers are reflected by the body to be analyzed (the body's internal and / or surface structures) and then return to the ultrasound transducer, which converts the ultrasound waves back into electrical signals. These electrical response signals can be read by the electronic control circuit and stored and analyzed to derive information about the body to be analyzed from the electrical response signals. Summary of the Invention [Problem to be solved by the invention]

[0003] It would be desirable to at least partially improve upon certain aspects of known ultrasound imaging devices. [Means for solving the problem]

[0004] To this end, an embodiment provides an ultrasonic imaging device comprising a collection of ultrasonic transducers, an acoustic coupling layer covering the collection of ultrasonic transducers, and a heating device adapted to heat an imaging target positioned on the acoustic coupling layer during an ultrasonic image acquisition stage.

[0005] According to an embodiment, the ultrasound imaging device further comprises an electronic power and control circuit.

[0006] According to an embodiment, the heating device is adapted to collect heat generated by the electronic power and control circuitry and dissipate all or a portion of the heat to the acoustic coupling layer above the ultrasonic transducer assembly.

[0007] According to an embodiment, the heating device comprises one or more metal foils arranged to conduct heat generated by the electronic power and control circuitry and dissipate all or a portion of the heat to the acoustic coupling layer above the ultrasonic transducer assembly.

[0008] According to an embodiment, the heating device further comprises one or more switches configured to interrupt heat transfer to the acoustic coupling layer if the internal temperature of the ultrasound imaging device exceeds a predetermined threshold.

[0009] According to an embodiment, the heating device comprises a flexible Peltier module having a cold side facing the electronic power and control circuitry and a hot side facing the image target.

[0010] According to an embodiment, the heating device includes a heating mat having a serpentine metal resistor disposed between the ultrasound transducer assembly and the imaging subject.

[0011] According to an embodiment, the heating mat is embedded in the acoustic coupling layer.

[0012] According to an embodiment, the heating mat covers the acoustic coupling layer.

[0013] According to an embodiment, the heating device comprises a heating layer integrated with the acoustic coupling layer and made of a thermoelectric polymer material.

[0014] According to an embodiment, the heating layer is electrically connected to the electronic power and control circuitry by a connection element.

[0015] According to an embodiment, the ultrasonic transducers in the collection of ultrasonic transducers are CMUT transducers, PMUT transducers, piezoelectric transducers, piezoelectric composite transducers, or single crystal transducers.

[0016] According to an embodiment, the acoustic coupling layer has at least one layer formed of an activatable polymer material configured to have a first Young's modulus during an ultrasound image acquisition phase and a second Young's modulus greater than the first Young's modulus outside the acquisition phase.

[0017] Another embodiment provides an ultrasound imaging device comprising a collection of ultrasound transducers and an acoustic coupling layer covering the collection of ultrasound transducers, the acoustic coupling layer being formed of an activatable polymer material configured to have a first Young's modulus during an ultrasound image acquisition phase and a second Young's modulus greater than the first Young's modulus outside the acquisition phase.

[0018] According to an embodiment, the acoustic coupling layer is formed of a thermally active polymer, a photoactive polymer, an electroactive polymer, or a polymer that can be activated under the influence of a chemical or mechanical stimulus.

[0019] According to an embodiment, the acoustic coupling layer is formed of a thermally active polymer, and the ultrasound imaging device includes a heating device configured to heat the acoustic coupling layer during an ultrasound image acquisition phase and to discontinue heating outside the acquisition phase.

[0020] According to an embodiment, the acoustic coupling layer is formed of a heat-activated polymer that can be directly activated under the effect of heat generated by an imaging object, for example a user's finger.

[0021] According to an embodiment, the acoustic coupling layer is formed of a thermally activated polymer that can be activated to have the first Young's modulus when its temperature exceeds a threshold value in the range of 25°C to 40°C.

[0022] According to an embodiment, the acoustic coupling layer is formed of a photoactive material having a Young's modulus that has a first value under the influence of light irradiation at a first wavelength A and returns to a second value under the influence of light irradiation at a second wavelength B different from the first wavelength A, or when the light irradiation at the first wavelength A is discontinued, or under the influence of another stimulus.

[0023] According to an embodiment, the ultrasound imaging device comprises one or more first light sources adapted to emit radiation at the first wavelength A through the acoustic coupling layer, and one or more second light sources adapted to emit radiation at the second wavelength B through the acoustic coupling layer.

[0024] According to an embodiment, the ultrasound imaging device further comprises an electronic power and control circuit for supplying power to and controlling the ultrasound transducer assembly, and the one or more first light sources and the one or more second light sources are controlled by the electronic power and control circuit.

[0025] According to an embodiment, the acoustic coupling layer is formed of an electroactive material having a Young's modulus that has a first value under the influence of an electrical bias and returns to a second value in the absence of the electrical bias.

[0026] According to an embodiment, the ultrasonic imaging device further comprises an electronic power supply and control circuit for supplying power to and controlling the ultrasonic transducer assembly, and a first electrode and a second electrode in contact with the acoustic coupling layer and connected to the electronic power supply and control circuit for applying the electrical bias.

[0027] According to an embodiment, the ultrasonic transducers in the collection of ultrasonic transducers are CMUT transducers, PMUT transducers, piezoelectric transducers, piezoelectric composite transducers, or single crystal transducers.

[0028] According to an embodiment, the ultrasound imaging device is adapted to heat an imaging target placed on the acoustic coupling layer during an acquisition phase of an ultrasound image. [Brief description of the drawings]

[0029] The foregoing and other features and advantages are described in detail in the remainder of the present disclosure of specific embodiments, given by way of non-limiting example with reference to the accompanying drawings, in which:

[0030] [Figure 1] 1A and 1B are schematic diagrams illustrating examples of ultrasound imaging devices according to embodiments. [Diagram 2] 2 is a schematic diagram of another example of an ultrasound imaging device according to an embodiment; FIG. [Diagram 3] 2 is a schematic diagram of another example of an ultrasound imaging device according to an embodiment; FIG. [Figure 4] 2 is a schematic diagram of another example of an ultrasound imaging device according to an embodiment; FIG. [Diagram 5] 2 is a schematic diagram of another example of an ultrasound imaging device according to an embodiment; FIG. [Figure 6] 2 is a schematic diagram of another example of an ultrasound imaging device according to an embodiment; FIG. [Figure 7] 2 is a schematic diagram of another example of an ultrasound imaging device according to an embodiment; FIG. [Figure 8] 2 is a schematic diagram of another example of an ultrasound imaging device according to an embodiment; FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Like features are indicated by like reference numerals in the various figures, and in particular, structural and / or functional features common to the various embodiments may have the same reference numerals and may have the same structural, dimensional and material characteristics.

[0032] For clarity, only those steps and elements useful for understanding the described embodiments are shown and detailed. In particular, the formation of the ultrasound transducers and electronic control circuits of the described devices has not been detailed, the described embodiments being compatible with the conventional formation of these elements. Furthermore, the various applications to which the described devices may be applied have not been detailed, the described embodiments being compatible with all or the most common applications of ultrasound imaging devices, and in particular with applications for imaging parts of the human or animal body.

[0033] Unless otherwise indicated, when referring to two elements connected together, this refers to a direct connection without any intermediate elements other than conductors, and when referring to two elements coupled together, this refers to the two elements being either connected or coupled through one or more other elements.

[0034] In the following description, when reference is made to terms that qualify absolute positions, such as "front", "back", "top", "bottom", "left", "right", or terms that qualify relative positions, such as "top", "bottom", "upper", "lower", or terms that qualify orientations, such as "horizontal", "vertical", unless otherwise specified, this term refers to the orientation of the drawing.

[0035] Unless otherwise specified, the terms "about," "approximately," "substantially," and "to the extent of" refer to plus or minus 10% of the applicable value, preferably plus or minus 5%.

[0036] FIG. 1 is a cross-sectional view that illustrates a schematic example of an ultrasound imaging device 100 according to an embodiment.

[0037] The device 100 of Fig. 1 comprises a collection 101 of ultrasonic transducers (US) arranged, for example, in an array, in a linear array or according to any other arrangement. The ultrasonic transducers of the collection 101 are, for example, transducers of the CMUT (Capacitive Membrane Ultrasonic Transducer) type, of the PMUT (Piezoelectric Membrane Ultrasonic Transducer) type, quartz transducers or any other type of ultrasonic transducer, for example a piezoelectric transducer or a piezoelectric composite transducer or a single crystal transducer.

[0038] The transducers of the assembly 101 are, for example, integrated in a monolithic chip or are, for example, formed in and on a semiconductor substrate, for example a silicon substrate, or formed in and on an insulating substrate, for example a glass substrate, and are not shown in detail in the drawings.

[0039] In the illustrated example, the transducer assembly 101 is mounted on a printed circuit board 103. The printed circuit board 103 comprises, for example, a support made of an electrically insulating material, for example plastic, and a collection of metal interconnection areas and tracks (not shown in detail in the drawings) formed on at least one side of the support. In this example, the ultrasonic transducer assembly 101 is fixed to and electrically connected to the upper surface of the printed circuit board 103.

[0040] The device 100 of FIG. 1 further comprises electronic power and control circuitry 110 .

[0041] The electronic power and control circuit 110 comprises a transmitting circuit 111 (PULS) adapted to provide electrical excitation signals to the ultrasonic transducers of the assembly 101 to cause the ultrasonic transducers to emit ultrasonic waves.

[0042] The electronic power and control circuit 110 further comprises a receiver circuit 113 (REC) adapted to read an electrical response signal generated by the ultrasonic transducer of the assembly 101 under the influence of ultrasonic waves received from the imaged object.

[0043] The electronic power and control circuit 110 further comprises a processing circuit 115 (PROC) for processing the electrical signals transmitted by the transmitting circuit 111 and / or received by the receiving circuit 113 .

[0044] The electronic power supply and control circuit 110 further comprises a power supply circuit 117 (SUPP), which is particularly adapted to electrically power the transmitting circuit 111, the receiving circuit 113 and / or the processing circuit 115.

[0045] The transmit circuit 111, the receive circuit 113, the processing circuit 115, and the power circuit 117 may be integrated, for example, on one or more integrated circuit chips. By way of example, the transmit circuit 111, the receive circuit 113, the processing circuit 115, and the power circuit 117 may be integrated, respectively, on four separate integrated circuit chips. However, the described embodiment is not limited to this particular case.

[0046] The transmitting circuit 111, the receiving circuit 113, the processing circuit 115, and the power supply circuit 117 are mounted, for example, on one or more printed circuit boards. In the illustrated example, the transmitting circuit 111 and the receiving circuit 113 are mounted on a printed circuit board 121, and the processing circuit 115 and the power supply circuit 117 are mounted on another printed circuit board 123. More specifically, in this example, the transmitting circuit 111 and the receiving circuit 113 are fixed to and electrically connected to the upper surface of the printed circuit board 121, and the processing circuit 115 and the power supply circuit 117 are fixed to and electrically connected to the upper surface of the printed circuit board 123.

[0047] In the example of FIG. 1, the ultrasonic transducer assembly 101 and electronic power and control circuitry 110 are monolithically integrated, e.g., in the same housing (not shown in the drawings), to form a monolithic ultrasonic imaging module.

[0048] In this example, the ultrasonic transducer assembly 101 is arranged above the electronic power and control circuitry 110. More specifically, in the illustrated example, the printed circuit board 103 is arranged above the assembly comprising the printed circuit board 121 and the transmitting circuitry 111 and the receiving circuitry 113, which is itself arranged above the assembly comprising the printed circuit board 123 and the processing circuitry 115 and the power circuitry 117. In other words, the printed circuit boards 123, 121 and 103 are stacked vertically. Mechanical fixing elements, not shown, may be provided for mechanically fixing the printed circuit boards to each other. Furthermore, electrical connection elements, not shown, may be provided for electrically connecting the printed circuit boards to each other.

[0049] A dielectric protective material 131, for example a protective resin, may be disposed between the printed circuit board 123 and the printed circuit board 121, and between the printed circuit board 121 and the printed circuit board 103. For example, the protective material 131 completely fills the gap between the printed circuit board 123 and the printed circuit board 121, and the gap between the printed circuit board 121 and the printed circuit board 103. The protective material 131 may further cover the lower surface of the printed circuit board 123 and the upper surface of the printed circuit board 103 around the ultrasonic transducer assembly 101.

[0050] The device 100 of Fig. 1 further comprises a bonding layer 140, for example made of a polymer material, which for example electrically insulates and covers the upper surface of the ultrasonic transducer assembly 101. For example, the bonding layer 140 is disposed on the upper surface of the ultrasonic transducer assembly 101 and is in contact with the upper surface of the ultrasonic transducer assembly 101. As a variant, the bonding layer 140 is fixed to the upper surface of the ultrasonic transducer assembly 101 via an adhesive layer not shown.

[0051] In the illustrated example, the bonding layer 140 further covers the top surface of the printed circuit board 103 around the ultrasonic transducer assembly 101. More specifically, in this example, the bonding layer 140 extends continuously across the entire surface of the printed circuit board 103.

[0052] The thickness of the bonding layer 140 is, for example, in the range of 100 μm to 5 mm, for example, in the range of 500 μm to 1 mm.

[0053] The upper surface of bonding layer 140 defines a contact surface upon which an imaging object may be placed, such as one or more fingers of a user, the palm of a user's hand, or any other part of a human or animal body which it is desired to image.

[0054] The coupling layer 140 has the function of ultrasonic coupling between the transducer of the assembly 101 and the object to be imaged. In particular, the coupling layer 140 is preferably relatively flexible and deformable to avoid the presence of an air gap between the transducer of the assembly 101 and the object to be imaged. Furthermore, the coupling layer 140 desirably has an acoustic impedance that is matched to the acoustic impedance of the object to be imaged, for example, an acoustic impedance substantially equal to the acoustic impedance of the skin. Thus, the coupling layer 140 can maximize the transmission of acoustic energy between the ultrasound transducer and the object to be analyzed.

[0055] Bonding layer 140 may further provide a protective function for the device, in particular the ultrasound transducers of assembly 101. In particular, it is desirable for bonding layer 140 to have a relatively high mechanical strength so as not to degrade over time in contact with the subject being imaged.

[0056] Experiments performed by the inventors have shown that in certain applications, such as imaging small blood vessels, the quality of the acquired images strongly depends on the temperature of the imaged object. For example, imaging the weak blood flow and small blood vessels at the tips of fingers and toes is difficult to achieve since these vessels are at the coldest tips and can be subject to vasoconstriction and therefore reduced blood flow.

[0057] According to an aspect of the first embodiment, a heating device is integrated into the imaging device, which is adapted to heat the imaging object during the acquisition phase of the ultrasound images, thereby allowing to increase the temperature of the object during acquisition and thus improving the quality of the acquired images, especially in microvascular imaging applications.

[0058] In the example of FIG. 1, the heating device 150 is a heat sink configured to collect heat generated by the electronic power and control circuitry 110 and conduct the heat to the top side of the device above the ultrasonic transducer assembly 101.

[0059] More specifically, in this example, the heating device 150 includes a first metal foil or layer 151 covering an upper surface of the transmitting circuit 111, a second metal foil or layer 153 covering an upper surface of the receiving circuit 113, a third metal foil or layer 155 covering an upper surface of the processing circuit 115, and a fourth metal foil or layer 157 covering an upper surface of the power circuit 117. Each of the metal foils 151, 153, 155, and 157 may extend continuously over the entire surface of the respective underlying electronic circuit 111, electronic circuit 113, electronic circuit 115, and electronic circuit 117, for example.

[0060] The heating device 150 of Fig. 1 further comprises a metal foil or metal layer 159 covering the top surface of the ultrasonic transducer assembly 101. The metal foil 159 extends continuously over the entire top surface of the ultrasonic transducer assembly 101, for example. As an example, the metal foil 159 is embedded in the bonding layer 140 between the top surface of the ultrasonic transducer assembly 101 and the top surface of the bonding layer 140. In other words, the metal foil 159 covers the lower part of the bonding layer 140 and is covered by the upper part of the bonding layer 140. As a variant, the metal foil 159 is disposed on the top surface of the bonding layer and is in contact with the top surface of the bonding layer.

[0061] The heating device 150 of FIG. 1 further includes metal regions 160 that thermally couple the metal foils 151 , 153 , 155 , 157 to an upper metal foil 159 .

[0062] 1, the heating device 150 further comprises four temperature switches 161, 163, 165, 167 thermally coupling the metal foils 151, 153, 155, 157, respectively, to the upper metal foil 159. Each of the switches 161, 163, 165, 167 is adapted to thermally connect the metal foils 151, 153, 155, 157, respectively, to the upper metal foil 159 in a first configuration and to thermally isolate the metal foils 151, 153, 155, 157, respectively, from the upper metal foil 159 in a second configuration.

[0063] The switches 161, 163, 165, 167 are mechanical switches, for example metal bimetallic switches, adapted to automatically switch from the first configuration to the second configuration when their temperature exceeds a first predefined threshold and from the second configuration to the first configuration when their temperature falls below a second predefined threshold that is less than or equal to the first threshold (hysteresis). As a variant, the switches 161, 163, 165, 167 are electrically controlled depending on the temperature measured by one or more temperature sensors of a device not shown in detail in the drawings. As a variant, the switches 161, 163, 165, 167 may be omitted and the heat collecting metal foils 151, 153, 155, 157 may be thermally connected directly to, for example, the upper metal foil 159.

[0064] During operation, heat generated by the electronic power and control circuitry 110 is collected by the collection foils 151 , 153 , 155 , 157 and conducted to the top surface of the device where it is dissipated by the dissipation foil 159 .

[0065] This allows the imaging subject to be heated during the ultrasound image acquisition phase.

[0066] Switches 161, 163, 165, 167, if applicable, can stop all or part of the heat flow transferred to the upper metal foil 159 if too much heat is generated by the electronic power and control circuitry 110 to prevent risk of burning the user and / or damage to the bonding layer 140 or the ultrasonic transducer. In this case, the heat flow may be redirected towards an auxiliary heat sink (not shown), for example located on the underside of the device.

[0067] 1 is that the heating device 150 collects heat generated by the electronic power and control circuitry 110 to heat the imaged object, thereby improving the quality of the acquired image. Another advantage is that the metal layer further shields the ultrasound transducer, ensuring its protection from possible electromagnetic interference.

[0068] FIG. 2 is a cross-sectional view that illustrates a schematic diagram of another example of an ultrasound imaging device 200 according to an embodiment.

[0069] Device 200 of FIG. 2 differs from device 100 of FIG. 1 essentially in that device 200 replaces heating device 150 of FIG.

[0070] The heating device 250 of Fig. 2 is a flexible Peltier module. The Peltier module 250 has the shape of a flexible strip or web and has a first surface 250a, referred to as the cold side, configured to be placed against a heat-generating device, and a second surface 250b, referred to as the hot side, configured to face a heat-dissipating area.

[0071] In this example, the Peltier module covers the top surface of the ultrasonic transducer assembly 101 and an edge of the Peltier module is folded under a portion of the electronic power and control circuitry 110.

[0072] 2, the transmitting circuit 111 and the receiving circuit 113 are fixed to and electrically connected to the bottom surface of the printed circuit board 103, and the edge of the Peltier module is folded under the bottom surfaces of the circuits 111 and 113 and over the circuits 115 and 117. In this example, the printed circuit board 121 may be omitted.

[0073] For example, the top of the Peltier module covering the ultrasonic transducer assembly 101 is embedded in the bonding layer 140 between the top surface of the ultrasonic transducer assembly 101 and the top surface of the bonding layer 140 .

[0074] In this example, at the top of Peltier module 250, hot surface 250b of the Peltier module faces the top surface of the ultrasound imaging device, i.e., faces the image subject. At the folded edge of Peltier module 250, cold surface 250a of the Peltier module contacts the underside of electronic circuitry 111 and electronic circuitry 113.

[0075] During operation, Peltier module 250 cools electronic circuitry 111 and electronic circuitry 113 and dissipates heat generated on hot surface sides, particularly the top surface side of the imaging device on which the imaged subject is placed.

[0076] An advantage of the device 200 of FIG. 2 is that the heating device 250 collects heat generated by the electronic power and control circuitry 110 to heat the imaged subject and still allow cooling of the electronic power and control circuitry 110.

[0077] FIG. 3 is a cross-sectional view that diagrammatically illustrates another example of an ultrasound imaging device 300 according to an embodiment.

[0078] Device 300 of FIG. 3 differs from device 100 of FIG. 1 essentially in that device 300 replaces heating device 150 of FIG.

[0079] Heating device 350 in FIG. 3 is, for example, a resistive heating mat having a metal resistor serpentine disposed between two sheets of electrically insulating material, such as polyimide.

[0080] The heating mat 350, for example, covers the entire upper surface of the ultrasonic transducer assembly 101. The heating mat 350 is connected to the power supply circuit 117, for example, for power supply.

[0081] In the example of FIG. 3, the heating mat 350 is embedded in the bonding layer 140 between the top surface of the ultrasonic transducer assembly 101 and the top surface of the bonding layer 140 .

[0082] An advantage of the device 350 of FIG. 3 is that the heating device 350 can be precisely controlled to obtain a desired temperature at the top surface of the bonding layer 140 .

[0083] FIG. 4 is a cross-sectional view that illustrates a schematic of an alternative embodiment of the ultrasound imaging device 300 of FIG.

[0084] In this variant, the heating mat 350 is flush with the top surface of the bonding layer 140. This variant is less favorable for skin print acquisition, since the image plane to be acquired (skin surface) is very close to the metal serpentine of the heating mat. As a result, depressions in the metal serpentine are superimposed on the image of the finger, reducing the acquisition quality. However, this variant is adapted for acquiring images of surfaces further away from the contact surface of the device, for example images of microvessels, so that the heating mat is not visible in the acquired image.

[0085] FIG. 5 is a cross-sectional view that illustrates a schematic diagram of another example of an ultrasound imaging device 500 according to an embodiment.

[0086] Device 500 of FIG. 5 differs from device 100 of FIG. 1 essentially in that device 500 replaces heating device 150 of FIG.

[0087] The heating device 550 comprises a heating layer 551 formed of a thermoelectric polymer material, ie a polymer material adapted to generate heat under the influence of an electrical bias.

[0088] The heating layer 551 is made, for example, of a material based on poly(3,4-ethylenedioxythiophene) (PEDOT) or a polymer material to which conductive nanoparticles such as silver nanowires have been added, so that it can obtain a level of conductivity that generates heat when subjected to electrical stress. Alternatively, the heating layer 551 is made of a transparent conductive oxide, for example indium tin oxide (ITO), fluorine-doped indium tin oxide (FTO) or aluminum-doped zinc oxide (AZO). Alternatively, the heating layer 551 is made of a material based on carbon nanotubes or graphene.

[0089] In this example, the heating layer 551 is integrated into the bonding layer 140. More specifically, in this example, the heating layer 551 covers a lower portion of the bonding layer 140 and is covered by an upper portion of the bonding layer 140.

[0090] In this example, the thickness of the heating layer 551 is relatively thin compared to the overall thickness of the bonding layer 140 .

[0091] For example, the thickness of the heating layer 551 is in the range of 50 to 200 nm, for example, about 100 nm.

[0092] The heating device 550 of FIG. 5 further includes an electrical connection element 553 electrically coupling the heating layer 551 to the electronic power circuitry 117 of the ultrasound imaging device.

[0093] FIG. 6 is a cross-sectional view that illustrates a schematic of an alternative embodiment of the ultrasound imaging device 500 of FIG.

[0094] In this variation, the heating layer 551 has a relatively large thickness and forms the majority of the thickness of the bonding layer 140. The bonding layer 140 may further comprise a relatively thin electrically insulating layer 552 covering the heating layer 551 to prevent any risk of electric shock to the user.

[0095] More generally, the heating devices 150, 250, 350, 550 of the imaging devices described in relation to Figures 1 to 6 may be replaced by any other heating device adapted to heat the imaging object during the acquisition phase of an ultrasound image of the imaging object, for example an infrared LED-based device.

[0096] According to aspects of the second embodiment, the coupling layer 140 of the ultrasound imaging device is formed of a polymeric material having mechanical properties, in particular Young's modulus, that can be modified under the influence of a stimulus, such as thermal (heating or cooling), optical, electrical, chemical (water, pH, etc.) or mechanical (pressure or impact) stimuli. The coupling layer 140 is configured to have a first Young's modulus during an ultrasound image acquisition phase and a second Young's modulus outside said acquisition phase that is greater than the first Young's modulus. In other words, the mechanical properties of the coupling layer 140 are controlled to enhance the acoustic coupling properties of the coupling layer 140 during acquisition. More specifically, the coupling layer 140 is made more compliant, e.g. softer or more flexible, during acquisition, and less compliant, e.g. harder or more rigid, outside the acquisition phase, so as to enhance the acoustic coupling between the transducer and the analyte, enhancing the mechanical protection properties provided by the coupling layer 140. By way of example, the Young's modulus of bonding layer 140 during acquisition of an ultrasound image is at least 10% lower, preferably at least 20% lower, more preferably at least 50% lower than outside the acquisition phase, e.g., when the imaging device is turned off. By way of example, the Young's modulus of bonding layer 140 during acquisition is less than 1.7 MPa, preferably less than 0.7 MPa, and outside acquisition is greater than 2.5 MPa, preferably greater than 5.5 MPa.

[0097] According to a first example of the second embodiment, the bonding layer 140 is made of a thermoactive polymer material, ie a polymer material having mechanical properties, in particular the Young's modulus, that are modified under the effect of heat.

[0098] In this case, the bonding device may comprise a heating device adapted to heat the bonding layer 140 to a temperature higher than the ambient temperature, for example higher than 25° C., preferably higher than 30° C., preferably higher than 35° C., preferably higher than 40° C., during the acquisition phase of the ultrasound images, in order to reduce the Young's modulus of the bonding layer 140. Outside the acquisition phase, the heating device may be interrupted to return the bonding layer 140 to the ambient temperature, thus increasing the Young's modulus of the bonding layer 140.

[0099] The heating device may be the same as or similar to the devices described above in relation to Figures 1 to 6. In other words, the first embodiment (heating the imaged object during acquisition) and the first example of the second embodiment (altering the mechanical properties of the bonding layer by heating during acquisition) may be combined.

[0100] Alternatively, the heat used to reduce the Young's modulus of the bonding layer during acquisition is simply the heat radiated by the imaging object itself, e.g. a user's finger, when the imaging object is placed on top of the bonding layer, in which case the imaging device does not need to comprise a specific heating device.

[0101] By way of example, the bonding layer 140 may be formed of a heat-activated polymer based on PTFE (polytetrafluoroethylene), PLA (polylactic acid), EVA (ethylene vinyl acetate), PCL (poly(ε-caprolactone)), tBA / PEGDMA (tert-butyl acrylate / poly(ethylene glycol) dimethacrylate), PU (polyurethane), PMMA (poly(methyl methacrylate)), polystyrene (PS) or silicone.

[0102] Alternatively, a similar operation can be achieved using a polymer whose mechanical properties are modified under the effect of cooling: in this case the heating device may be replaced by a cooling device.

[0103] FIG. 7 is a cross-sectional view that diagrammatically illustrates a second example of an ultrasound imaging device 700 according to a second embodiment.

[0104] In this example, the bonding layer 140 is formed of a photoactive polymer material, ie, a polymer material that has mechanical properties, particularly Young's modulus, that are altered under the influence of radiation.

[0105] Device 700 of FIG. 7 includes substantially the same elements as device 100 of FIG.

[0106] In this example, bonding layer 140 is formed of a photoactive polymer having a Young's modulus that has a relatively low first value under the influence of light irradiation at a first wavelength A and returns to a relatively high second value under the influence of light irradiation at a second wavelength B that is different from the first wavelength A.

[0107] Wavelength A and Wavelength B are, for example, visible light wavelengths or infrared wavelengths, however, the described embodiments are not limited to this particular case.

[0108] The device 700 comprises one or more light sources 710 adapted to emit radiation at wavelength A through the bonding layer 140 and one or more light sources 712 adapted to emit radiation at wavelength B through the bonding layer 140. The light sources 710 and 712 are, for example, fixedly connected to the printed circuit board 103 at the periphery of the ultrasound transducer assembly 101. The light sources 710 and 712 are, for example, light emitting diodes (LEDs) adapted to emit at wavelengths A and B, respectively.

[0109] The electronic power and control circuitry 110 is configured to activate one or more light sources 710 prior to the ultrasound image acquisition stage, e.g., when an imaged object is detected in front of the ultrasound transducer assembly 101, to cause the bonding layer 140 to become relatively soft and enhance acoustic coupling properties, and then, after acquisition, activate one or more light sources 712 to cause the bonding layer 140 to become relatively hard and enhance mechanical protection properties.

[0110] For example, when a user places a finger on top of layer 140 to capture a fingerprint, electronic power and control circuitry 110 can activate radiation at wavelength A, thereby releasing stress and allowing layer 140 to conform to the shape of the finger. At the end of capture, the polymer regains its smooth shape (in other words, the top surface of layer 140 becomes substantially flat again), and activation of radiation at wavelength B can harden the polymer and keep layer 140 in this state.

[0111] The example embodiment of Figure 7 may be advantageously adapted to an optoacoustic imaging device, i.e., a device in which modulated light is emitted towards an imaging target during acquisition of an ultrasound image. In this case, the same light source may be used to emit modulated light during acquisition to soften the binding polymer of layer 140 (wavelength A).

[0112] Alternatively, the return to the initial state (relatively high Young's modulus) may be achieved simply by discontinuing the irradiation at wavelength A, or by heating or cooling, or under the influence of another stimulus. In this case, the light source emitting at wavelength B may be omitted.

[0113] By way of example, the tie layer 140 may be formed of a photoactive polymer that includes diazo-type groups, acrylate derivatives, cinnamic derivatives, furan derivatives, or other groups known for their photosensitive properties. One skilled in the art can select the appropriate group depending on the chemical compatibility of the tie layer 140 with the tie polymer and the desired photoactivatable properties.

[0114] FIG. 8 is a cross-sectional view that diagrammatically illustrates a third example of an ultrasound imaging device 800 according to the second embodiment.

[0115] In this example, bonding layer 140 is formed of an electroactive polymer material, ie, a polymer material having mechanical properties, particularly Young's modulus, that are altered under the influence of an electrical bias, for example under the influence of a voltage.

[0116] Device 800 of FIG. 8 includes substantially the same elements as device 100 of FIG.

[0117] In this example, bonding layer 140 is formed of an electroactive polymer having a Young's modulus that has a relatively low first value under the influence of an electrical bias, e.g., voltage, applied between an electrode E and a power source F in contact with the electroactive polymer, and a relatively high second value in the absence of the electrical bias.

[0118] Electrodes E and F each contact the polymer of tie layer 140, for example near two opposing side edges of tie layer 140.

[0119] Electrodes E and F are coupled to the device's electronic power circuitry 117, for example, to apply an electrical bias.

[0120] The electronic power supply and control circuitry 110 is configured to apply an electrical bias prior to an ultrasound image acquisition phase, e.g., when an imaged object is detected in front of the ultrasound transducer assembly 101, to render the bonding layer 140 relatively soft and increase its acoustic coupling properties, and then, after the acquisition phase, to discontinue the electrical bias to render the bonding layer 140 relatively hard and increase its mechanical protection properties.

[0121] For example, when a user places a finger on top of layer 140 to capture a fingerprint, electronic power and control circuitry 110 activates an electrical bias in layer 140, thereby releasing stress and allowing layer 140 to conform to the shape of the finger. At the end of capture, the polymer regains its smooth shape (in other words, the top surface of layer 140 becomes substantially flat again), and turning off the electrical bias can harden the polymer and keep layer 140 in this state.

[0122] By way of example, the bonding layer 140 is made of an electroactive polymer selected from the group of polyacrylates, polyurethanes, latex, natural rubber, silicones, butadiene-acrylonitrile copolymers, piezoelectric polymers of the PVDF (polyvinylidene fluoride) type, or its copolymers P(VDF-TrFE) (vinylidene fluoride and trifluoroethylene).

[0123] In connection with the second embodiment, a use example has been described above in which the bonding layer 140 is configured to have a first Young's modulus during an acquisition phase of an ultrasound image and a second Young's modulus outside said acquisition phase, e.g. when the device is switched off, which is greater than the first Young's modulus. Depending on the intended application, two successive acquisition phases may be provided, during which the bonding layer is configured to have different Young's moduli. As an example, a first acquisition phase is performed by configuring the bonding layer 140 to have a relatively high Young's modulus, and then a second acquisition phase is performed by configuring the bonding layer 140 to have a relatively low Young's modulus. During the first acquisition phase, the bonding layer is relatively hard. Thus, for example, a fingerprint image of the surface may be acquired, for example by electrical impedance methods. During the second acquisition phase, the bonding layer is relatively soft (highly compliant). Thus, a depth image, for example a microvascular image, of the part of the body to be imaged may be acquired, for example by Doppler imaging methods. This device therefore makes it possible to perform two modes of acquisition within a very short time interval using the same coupling material.

[0124] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these various embodiments and variations can be combined, and other variations will occur to those skilled in the art. In particular, the described embodiments are not limited to the example materials and dimensions described in this disclosure.

[0125] Furthermore, the skilled person may combine the various embodiments described above depending on the needs of the target application. In particular, the skilled person may combine the first and second embodiments described above to obtain both advantages related to the heating of the imaged object during acquisition and advantages related to the adaptation of the mechanical properties of the bonding layer under the influence of a stimulus. In particular, the example embodiment of FIG. 7 and the example embodiment of FIG. 8 may be combined with the example embodiment of FIG. 1, the example embodiment of FIG. 2, the example embodiment of FIG. 3, the example embodiment of FIG. 4, the example embodiment of FIG. 5 or the example embodiment of FIG. 6.

[0126] Furthermore, although only application examples to ultrasound imaging devices are described above, those skilled in the art will understand, based on the teachings herein, how to adapt the described embodiments to other ultrasound emitting and / or receiving devices, such as devices for treating the human or animal body with ultrasound radiation, or non-destructive ultrasound inspection equipment that does not necessarily have to be applied to the human or animal body.

[0127] Finally, the actual implementation of the described embodiments and variations is within the skill of those skilled in the art based on the functional representations given above.

[0128] This application is based on and claims priority to French Patent Application No. 2114110, filed December 21, 2021, entitled "Ultrasound Imaging Device", which is incorporated herein by reference as permitted by law.

Claims

1. 1. An ultrasound imaging device (100; 200; 300; 500; 700; 800), comprising: The ultrasonic transducer includes an ultrasonic transducer assembly (101) and an acoustic coupling layer (140) that covers the ultrasonic transducer assembly (101), An ultrasonic imaging device, wherein the acoustic coupling layer (140) is formed of an activatable polymeric material configured to have a first Young's modulus during an ultrasonic image acquisition phase and a second Young's modulus when the ultrasonic imaging device is powered off.

2. 10. The ultrasound imaging device of claim 1, wherein the acoustic coupling layer is formed of a thermally active polymer, a photoactive polymer, an electroactive polymer, or a polymer that can be activated under the influence of a chemical or mechanical stimulus.

3. The acoustic coupling layer (140) is formed of a thermally active polymer; 3. The ultrasonic imaging device (100; 200; 300; 500) of claim 1 or 2, comprising a heating device (150; 250; 350; 550) configured to heat the acoustic coupling layer (140) during an ultrasonic image acquisition phase and to discontinue heating outside the acquisition phase.

4. 3. The ultrasound imaging device of claim 1, wherein the acoustic coupling layer (140) is formed of a thermoactive polymer that can be directly activated under the effect of heat generated by an imaging object, e.g., a user's finger.

5. 5. The ultrasonic imaging device of claim 1, wherein the acoustic coupling layer is formed of a thermally active polymer that can be activated to have the first Young's modulus when its temperature exceeds a threshold value in a range of 25° C. to 40° C.

6. The ultrasonic imaging device (700) of claim 1 or 2, wherein the acoustic coupling layer (140) is formed of a photoactive material having a Young's modulus that has a first value under the influence of light irradiation at a first wavelength A and returns to a second value under the influence of light irradiation at a second wavelength B different from the first wavelength A, or when the light irradiation at the first wavelength A is discontinued, or under the influence of another stimulus.

7. 7. The ultrasound imaging device (700) of claim 6, comprising one or more first light sources (710) adapted to emit radiation at the first wavelength A through the acoustic coupling layer (140), and one or more second light sources (712) adapted to emit radiation at the second wavelength B through the acoustic coupling layer (140).

8. an electronic power supply and control circuit (110) for powering and controlling the ultrasonic transducer assembly (101); 8. The ultrasound imaging device (700) of claim 7, wherein the one or more first light sources (710) and the one or more second light sources (712) are controlled by the electronic power and control circuitry (110).

9. 3. The ultrasonic imaging device of claim 1, wherein the acoustic coupling layer is formed of an electroactive material having a Young's modulus that has a first value under the influence of an electrical bias and returns to a second value in the absence of the electrical bias.

10. an electronic power supply and control circuit (110) for powering and controlling said ultrasonic transducer assembly (101); a first electrode (E) and a second electrode (F) in contact with the acoustic coupling layer (140) and connected to the electronic power supply and control circuitry (110) for applying the electrical bias; 10. The ultrasound imaging device of claim 9, further comprising:

11. 11. The ultrasonic imaging device (100; 200; 300; 500; 700; 800) of claim 1, wherein the ultrasonic transducers of the ultrasonic transducer assembly (101) are CMUT transducers, PMUT transducers, piezoelectric transducers, piezoelectric composite transducers, or single crystal transducers.

12. 12. The ultrasonic imaging device of claim 1, adapted to heat an imaging target arranged on the acoustic coupling layer (140) during an acquisition phase of an ultrasonic image.

13. 13. The ultrasonic imaging device of claim 1, configured to sequentially perform an acquisition stage in which the acoustic coupling layer (140) is configured to have the first Young's modulus and another acquisition stage in which the acoustic coupling layer (140) is configured to have a higher Young's modulus.

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