Ultrasound imaging device

Abstract

The present description relates to an ultrasound imaging device (200) comprising a set of ultrasound transducers (101), an acoustic coupling layer (105) covering the set of ultrasound transducers (101) and a suction system (203) suitable for exerting a suction force designed to press an object to be imaged (111) that is arranged facing the acoustic coupling layer (105) against an upper surface of the coupling layer (105).

Description

DESCRIPTION TITLE: Ultrasound Imaging Device This application is based on, and claims priority from, French patent application FR2303100 filed on March 30, 2023, entitled "Ultrasonic Imaging Device", which is considered to form an integral part of this description within the limits provided by law. Technical field

[0001] This description relates to the field of ultrasound imaging devices, and more specifically to skin impression acquisition devices and / or microvascular imaging devices based on ultrasound transducers. Prior art

[0002] An ultrasound imaging system typically comprises multiple ultrasonic transducers and an electronic control circuit connected to them. In operation, the transducers are positioned facing an object or body whose image is to be acquired. The electronic control circuit is configured to apply electrical excitation signals to the transducers, causing them to emit ultrasonic waves towards the body being analyzed. These ultrasonic waves are reflected by the body (through its internal and / or surface structure) and then return to the transducers, which convert them back into electrical signals. These electrical response signals are read by the electronic control circuit and can be stored and analyzed to derive information about the body being examined.

[0003] It would be desirable to improve, at least in part, certain aspects of known ultrasound imaging devices. Summary of the invention

[0004] For this purpose, one embodiment provides an ultrasonic imaging device comprising an array of ultrasonic transducers, an acoustic coupling layer covering the array of ultrasonic transducers, and a suction system adapted to exert a suction force tending to press against an upper surface of the coupling layer an object to be imaged arranged opposite the acoustic coupling layer.

[0005] According to one embodiment, the device includes a protective housing comprising a top plate located above the acoustic coupling layer, such that a cavity separates a lower face of the top plate of the housing from the upper face of the acoustic coupling layer.

[0006] According to one embodiment, the upper plate has a through opening intended to be placed opposite the object to be imaged.

[0007] According to one embodiment, the through-opening is located opposite the assembly of ultrasonic transducers.

[0008] According to one embodiment, the suction system is connected to said cavity by an airtight conduit.

[0009] According to one embodiment, the suction system is configured to apply at least a partial vacuum in the cavity during an ultrasonic image acquisition phase, so as to press the object to be imaged against the upper face of the acoustic coupling layer.

[0010] According to one embodiment, the acoustic coupling layer is made of a polymer material.

[0011] According to one embodiment, the suction system includes a vacuum pump.

[0012] One embodiment provides for the use of an ultrasonic imaging device as defined above, for the acquisition of biometric images.

[0013] One embodiment provides for the use of an ultrasound imaging device as defined above, for the acquisition of medical images.

[0014] One embodiment provides for the use of an ultrasonic imaging device as defined above, for ultrasonic non-destructive testing applications. Brief description of the drawings

[0015] These and other features and advantages will be set forth in detail in the following description of particular embodiments given without limitation in relation to the attached figures, among which:

[0016] Figure 1 is a cross-sectional view schematically representing an example of an ultrasound imaging device;

[0017] Figures 2A and 2B are cross-sectional views schematically representing an example of an ultrasonic imaging device according to one embodiment. Description of the embodiments

[0018] The same elements have been designated by the same references in the different figures. In particular, the structural and / or functional elements common to the different embodiments may have the same references and may have identical structural, dimensional and material properties.

[0019] For the sake of clarity, only the steps and elements necessary for understanding the described embodiments have been shown and detailed. In particular, the implementation of the ultrasonic transducers and the electronic control circuits of the described devices has not been detailed, as the described embodiments are compatible with common implementations of these components. Furthermore, the various applications of the described devices have not been detailed, as the described embodiments are compatible with all or most common applications of ultrasonic imaging devices, and in particular, applications for imaging parts of the human or animal body.

[0020] 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 connected (in English "coupled") together, this means that these two elements can be connected or be connected by means of one or more other elements.

[0021] In the description that follows, when referring to absolute positional qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative positional qualifiers, such as the terms "above", "below", "superior", "inferior", etc., or to orientational qualifiers, such as the terms "horizontal", "vertical", etc., unless otherwise specified, it refers to the orientation of the figures.

[0022] Unless otherwise specified, the expressions "about", "approximately", "substantially", and "of the order of" mean to within 10%, preferably to within 5%.

[0023] Figure 1 is a cross-sectional view schematically representing an example of an ultrasonic imaging device 100, for example for biometric applications.

[0024] The device 100 of Figure 1 comprises an assembly 101 of ultrasonic transducers (not detailed in the figure), for example arranged in a matrix, in a strip, or in any other arrangement. The transducers of the assembly 101 are, for example, CMUT type transducers (capacitive ultrasonic membrane transducers), PMUT type transducers (piezoelectric membrane transducers), crystal transducers, or any other type of ultrasonic transducer, for example piezoelectric or piezocomposite transducers, or single crystal transducers.

[0025] The transducers of the set 101 are for example integrated into a monolithic chip, for example formed in and on a semiconductor substrate, for example a silicon substrate, or in and on an insulating substrate, for example a glass substrate (not detailed in the figure).

[0026] In the example shown, the transducer assembly 101 is mounted on a printed circuit board 103. The printed circuit board 103 includes, for example, a substrate made of an electrically insulating material, such as plastic, and a set of metallic interconnecting pads and traces (not detailed in the figure) formed on at least one face of the substrate. In this example, the ultrasonic transducer assembly 101 is fixed and electrically connected to the top face of the printed circuit board 103.

[0027] The device 100 in Figure 1 may further include one or more electronic circuits (not shown) for powering and controlling the assembly 101 of ultrasonic transducers. The electronic circuits power supply and control components are, for example, fixed and electrically connected to one side of the printed circuit board 103.

[0028] The electronic power and control circuits include, for example, transmitting circuits adapted to provide electrical excitation signals to the ultrasonic transducers so as to cause the transducers to emit ultrasonic waves, and receiving circuits adapted to read electrical response signals generated by the ultrasonic transducers of assembly 101 under the effect of an ultrasonic wave received from the object to be imaged.

[0029] The device 100 of Figure 1 further comprises a coupling layer 105, for example made of a polymer material, for example electrically insulating, coating the upper surface of the ultrasonic transducer assembly 101. By way of example, the layer 105 is disposed on and in contact with the upper surface of the ultrasonic transducer assembly 101. Alternatively, the layer 105 is fixed to the upper surface of the transducer assembly 101 by means of an adhesive layer, not shown.

[0030] For example, the coupling layer 105 extends continuously over the entire upper surface of the ultrasonic transducer assembly 101. In the example shown, the coupling layer also extends laterally beyond the edges of the elementary transducer assembly 101, and thus also covers the sides of the assembly 101.

[0031] The thickness of the coupling layer 105 is for example between 100 pm and 10 mm, for example between 500 pm and 2 mm.

[0032] The top face of layer 105 defines a contact surface on which an object to be imaged is placed, for example one or more fingers of a user, the palm of a user, or any other part of the human or animal body that we wish to image.

[0033] Layer 105 provides ultrasonic coupling between the transducers of assembly 101 and the object being imaged. Specifically, layer 105 is preferably relatively flexible and deformable to avoid air gaps between the transducers of assembly 101 and the object being imaged. Furthermore, layer 105 preferably has an acoustic impedance matched to that of the object being imaged, for example, an acoustic impedance approximately equal to the acoustic impedance of skin. Thus, layer 105 maximizes the transfer of acoustic energy between the ultrasonic transducers and the object being analyzed.

[0034] Layer 105 can also have a protective function for the device and in particular for the ultrasonic transducers of assembly 101. In particular, layer 105 preferably has a relatively high mechanical strength so as not to degrade over time and in contact with the objects to be imaged.

[0035] In the example shown in Figure 1, the acoustic coupling layer 105 and the transducer assembly 101 are encapsulated in a protective housing 107, for example, made of a rigid material, such as a metallic material or an electrically insulating material such as plastic. The protective housing 107 includes a through-opening or window 109 opposite the ultrasonic transducer assembly, allowing free access to the upper surface of the acoustic coupling layer 105.

[0036] In operation, the object to be imaged is placed in contact with the upper face of the acoustic coupling layer 105 opposite the opening 109.

[0037] In the example shown in Figure 1, the object to be imaged is a finger 111. The opening 109, for example, has approximately the same dimensions as those of a portion of the finger, for example, an end of the finger, which we are trying to image.

[0038] In practice, to avoid the presence of an air gap between the surface of the finger and the coupling layer 105, and to limit the risks of finger movement, users tend to apply relatively high pressure to the coupling layer 105 with their finger throughout the entire duration of an ultrasound image acquisition phase.

[0039] Experiments conducted by the inventors have shown that, for certain applications, such as microvascular imaging, the quality of acquired images can be degraded due to pressure exerted by the user during acquisition. For example, imaging low blood flow and microscopic vessels113 located at the tips of the fingers and toes is difficult because these vessels can be compressed, thus reducing blood flow.

[0040] Figures 2A and 2B are cross-sectional views schematically representing an example of an ultrasonic imaging device 200 according to one embodiment.

[0041] Device 200 includes elements common to Device 100 in Figure 1. These elements will not be detailed again. Only the differences with Device 100 in Figure 1 will be detailed below.

[0042] Device 200 differs from device 100 in Figure 1 primarily in that it includes a motorized suction system designed to exert suction force that presses the object to be imaged against the upper surface of the coupling layer 105. Thus, the user does not have to manually apply pressure to press the object against the surface of the coupling layer 105. This limits the risk of excessive compression of the object, which can degrade the quality of the acquired ultrasound images. In particular, for microvascular imaging applications, this prevents undesirable compression of the vessels being imaged.

[0043] In the example of Figures 2A and 2B, the protective housing 107 includes a top plate 107a arranged above the top face of the acoustic coupling layer 105. In this example, the housing 107 is arranged so that an air gap or cavity 201 separates the top face of the acoustic coupling layer 105 from the bottom face of the top plate 107a of the housing.

[0044] The air gap or cavity 201 can have a relatively small thickness, for example between 0.1 mm and 10 mm, for example between 0.5 mm and 5 mm.

[0045] When the user places their finger on the device, the latter comes into contact with and supports the upper face of the plate 107a. A central part of the finger, corresponding to the part to be imaged, closes the opening 109 and is thus opposite the upper face of the coupling layer 105, separated from the upper face of the layer 105 only by the cavity 201.

[0046] The air gap or cavity 201 is connected to a suction system 203 (not shown in detail in the figure) via a sealed duct (not shown in detail in the figure). For example, the air gap or cavity 201 is connected to the outside atmosphere to the housing 107 only via the opening 109 and the suction system 203.

[0047] The 203 suction system is, for example, a vacuum pump, or any other motorized suction system. The provision of a relatively thin air gap allows for an advantageous reduction in the overall size of the suction system.

[0048] Figure 2A illustrates a configuration in which the motorized suction system 203 is inactive. In this case, the finger rests on the upper plate 107a of the protective housing, with the portion of the finger to be imaged completely or partially obstructing the opening 109. It should be noted that, in this configuration, the portion of the finger to be imaged is not in contact with the upper surface of the acoustic coupling layer 105 but is separated from it by the air gap 201. Due to the presence of an air gap between the finger and the acoustic coupling layer 105, this configuration is not suitable for acquiring an ultrasonic image.

[0049] Figure 2B illustrates a configuration in which the motorized suction system 203 is active. In this case, at least a partial vacuum is created in the cavity 201, drawing the portion of the finger to be imaged into the cavity. Under the effect of the suction, the portion of the finger to be imaged is pressed against the upper surface of the acoustic coupling layer 105. An ultrasonic image of the finger can then be acquired.

[0050] The suction applied during the acquisition phase has several advantages.

[0051] In particular, it allows the finger, or more generally any object or organ to be imaged, to be held in position opposite the assembly 101 of ultrasonic transducers, in contact with the upper face of the coupling layer 105, via a calibrated suction force automatically controlled via a motorized system.

[0052] This allows, for example, the sensor to be held in place autonomously during data acquisition, without the need for a specific holding system, whether human or mechanical.

[0053] This also helps to avoid micromovements of the area to be imaged, which could degrade the quality of the acquired images.

[0054] This also helps to avoid the risk of the user applying excessive manual pressure, which could lead to deforming or compressing the object being imaged and thus degrading the quality of the acquired image.

[0055] In microvascular imaging applications, one advantage is that it prevents the blood vessels in the portion of the finger being imaged from being compressed, which could compromise the quality of the acquired image. Conversely, suction can cause localized dilation of the portion of the finger being imaged, improving image quality.

[0056] Compared to device 100 in Figure 1, the proposed solution also allows for an increase in the contact area between the finger and the acoustic coupling layer 105.

[0057] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will become apparent to them. In particular, the embodiments described are not limited to the example arrangement of the suction system 203 and the protective housing 107 of the device shown in figures 2A and 2B. More generally, a person skilled in the art will be able to adapt the arrangement of the suction system 203 and the protective housing 107 according to the application considered and the type of object to be imaged.

[0058] Furthermore, the described embodiments are not limited to the application example mentioned above for microvascular imaging devices. As an alternative, the proposed suction system can be applied to fingerprint acquisition devices to facilitate the placement and maintenance of the finger during acquisition.

[0059] Furthermore, the embodiments described are not limited to biometric applications but can be adapted to any ultrasound imaging system of portions of the human or animal body, for example for medical applications.

[0060] Furthermore, the described embodiments can be applied to ultrasonic imaging devices for non-living objects, for example, for non-destructive ultrasonic testing applications. The provision of a motorized suction system then facilitates the placement and maintenance of the acquisition device in position relative to the object to be imaged.

[0061] 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

CLAIMS 1. Ultrasound imaging device (200) comprising a set of ultrasonic transducers (101), an acoustic coupling layer (105) coating said set of ultrasonic transducers (101), and a motorized suction system (203) adapted to exert a suction force tending to press against an upper surface of the coupling layer (105) an object to be imaged (111) arranged opposite the acoustic coupling layer (105).

2. An ultrasound imaging device (200) according to claim 1, comprising a protective housing (107) comprising a top plate (107a) located above the acoustic coupling layer (105), such that a cavity (201) separates a lower face of the top plate (107a) of the housing (107) from the upper face of the acoustic coupling layer (105).

3. Ultrasound imaging device (200) according to claim 2, wherein said upper plate (107a) has a through opening (109) intended to be placed opposite the object (111) to be imaged.

4. Ultrasound imaging device (200) according to claim 3, wherein said through opening (109) is located opposite the set (101) of ultrasonic transducers.

5. An ultrasound imaging device (200) according to any one of claims 2 to 4, wherein the suction system (203) is connected to said cavity (201) by a hermetic conduit.

6. The ultrasound imaging device (200) of any one of claims 2 to 5, wherein the suction system (203) is configured to apply a vacuum to the less partial in the cavity during a phase of acquisition of an ultrasonic image, so as to press the object to be imaged (111) against the upper face of the acoustic coupling layer (105).

7. An ultrasound imaging device (200) according to any one of claims 1 to 6, wherein the acoustic coupling layer (105) is made of a polymer material.

8. An ultrasound imaging device (200) according to any one of claims 1 to 7, wherein the suction system comprises a vacuum pump.

9. Use of an ultrasound imaging device (200) according to any one of claims 1 to 8, for the acquisition of biometric images.

10. Use of an ultrasound imaging device (200) according to any one of claims 1 to 8, for the acquisition of medical images.

11. Use of an ultrasound imaging device (200) according to any one of claims 1 to 8, for non-destructive ultrasonic testing applications.

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