Flexible ultrasonic transducer and method for manufacturing the same

Abstract

The present invention relates to a flexible ultrasonic transducer and a method for manufacturing the same. The flexible ultrasonic transducer according to one embodiment of the present invention comprises: a substrate having a shape having a central portion and a plurality of long extensions extending from the central portion; an ultrasonic probe located in the central portion of the substrate and used to obtain an ultrasonic image of a region of interest; and a focused ultrasonic output portion located in the extension portion of the substrate and configured to output focused ultrasonic waves to the region of interest, wherein the focused ultrasonic output portion located in the extension portion of the substrate has flexible characteristics and is deformable. According to the structure of the embodiment, ultrasonic imaging and ultrasonic treatment such as stimulation or removal of lesions can be performed simultaneously, and the focus position of the focused ultrasonic wave can be adjusted or the focus sensitivity can be increased by soft movement.

Description

Technical Field

[0001] The present invention relates to an ultrasonic transducer and a method for manufacturing the same, and more particularly, to a dual-mode ultrasonic transducer and a method for manufacturing the same, wherein the dual-mode ultrasonic transducer comprises an ultrasonic probe disposed at the center of a substrate, and a focused ultrasonic output portion disposed at an extension portion of the substrate having flexible characteristics, and is capable of simultaneously performing ultrasonic image acquisition and focused ultrasonic therapy.

[0002] Description of nationally supported research and development

[0003] This research was conducted under the supervision of the Korea Advanced Institute of Science and Technology and supported by the Bio and Medical Technology Development Project of the Ministry of Science and ICT (Development of Ultrasonic Probe and Attachment-Type Device Using Semiconductor Technology, Project Identification Numbers: 1711093060, 1711105874). Background Art

[0004] The ultrasonic probe is composed of an array of ultrasonic transducers, each of which can simultaneously function as a transmitter that outputs an ultrasonic beam to the region of interest and a receiver that receives an ultrasonic beam reflected from an object in the region of interest. By calculating the time points of sending and receiving the ultrasonic beam, the round-trip time of the ultrasonic wave can be measured, and image information of the object in the region of interest can be generated based on this. The ultrasonic image information generated in this way can be visualized through a display. Ultrasonic probes are widely used in the medical field because they can capture images of the inside of the body in a non-invasive manner.

[0005] In the prior art, in order to relieve the patient's pain or stimulate the nerve cells in a specific part of the body, electrodes are inserted into the patient's body, but there is a possibility of physical damage due to this physical trauma process. In recent years, ultrasound stimulation therapy that can stimulate the affected part without a physical trauma process is widely used. Ultrasound can be divided into high-intensity focused ultrasound (HIFU) and low-intensity focused ultrasound (LIFU) according to its intensity. It is known that high-intensity focused ultrasound is used for direct treatment of living tissue such as cancer cells, tumors, and lesions in a physical way, while low-intensity focused ultrasound can still achieve medical effects without causing necrosis of body tissues. For example, low-intensity focused ultrasound can be used to treat neurological diseases such as cognitive impairment, anxiety, and depression in a non-invasive manner, or high-intensity focused ultrasound can be used to remove lesions in a non-invasive manner.

[0006] However, existing treatment methods based on focused ultrasound are not a method of directly removing lesions by grasping their location in real time. Instead, medical staff are required to perform surgery while observing photos of the patient's internal body taken in advance through CT or MRI, which inevitably leads to reduced accuracy. In addition, since the boundary between the lesion and other tissues cannot be accurately grasped, there is a risk of damaging functionally important tissues that do not need to be cut. Summary of the invention

[0007] The object of the present invention is to provide a dual-mode flexible ultrasonic transducer and a method for manufacturing the same, which can simultaneously perform ultrasonic image acquisition and treatment based on focused ultrasound, and can adjust the focus position or improve the focus sensitivity through soft movement.

[0008] A flexible ultrasonic transducer according to one embodiment includes: a substrate having a shape having a central portion and a plurality of long extension portions extending from the central portion; an ultrasonic probe located in the central portion of the substrate and used to obtain an ultrasonic image of a region of interest; and a focused ultrasonic output portion located in the extension portion of the substrate and configured to output focused ultrasonic waves to the region of interest, wherein the focused ultrasonic output portion located in the extension portion of the substrate has flexible characteristics and is capable of deformation.

[0009] According to an embodiment, the ultrasound probe may include an arrangement of a plurality of imaging ultrasound output elements configured to output imaging ultrasound toward the region of interest.

[0010] According to an embodiment, the ultrasound probe may include the plurality of imaging ultrasound output elements configured in a linear one-dimensional arrangement or the plurality of ultrasound output elements configured in a circular or quadrilateral two-dimensional arrangement.

[0011] According to one embodiment, the focused ultrasound output unit may include an array of a plurality of focused ultrasound output elements configured to output therapeutic focused ultrasound to the region of interest.

[0012] According to one embodiment, the extension portion of the substrate may have a plurality of groove structures formed at fixed intervals, and the focused ultrasonic output portion may include a flexible material layer, which covers the plurality of groove structures and the arrangement of the plurality of focused ultrasonic output elements.

[0013] According to an embodiment, the focused ultrasonic wave output portion may further include a reinforcing layer below the extension portion of the substrate, wherein the reinforcing layer is made of a material having a thermal expansion coefficient greater than that of the flexible material layer.

[0014] According to one embodiment, the therapeutic focused ultrasound may be low-intensity focused ultrasound (LIFU) for stimulating the region of interest at a low intensity or high-intensity focused ultrasound (HIFU) for physically removing lesions in the region of interest.

[0015] According to an embodiment, the imaging ultrasonic output element and the focusing ultrasonic output element may be micromachined ultrasonic transducers (Micromachined Ultrasound Transducer; MUT).

[0016] A method for manufacturing a flexible ultrasonic transducer according to one embodiment includes: providing a substrate; arranging a plurality of focused ultrasonic output elements at fixed intervals on the substrate; forming a photoresist on the plurality of focused ultrasonic output elements; etching the substrate to form a plurality of groove structures between the plurality of focused ultrasonic output elements; and forming a flexible material layer covering the plurality of groove structures and the plurality of focused ultrasonic output elements.

[0017] According to an embodiment, the ultrasonic output element may be a micromachined ultrasonic transducer.

[0018] According to an embodiment, the flexible material layer may be formed of an elastic polymer including at least one of PDMS (polydimethylsiloxane), polyurethane, polyester and a mixture thereof.

[0019] According to an embodiment, the method may further include forming a reinforcement layer below the substrate, wherein the reinforcement layer is made of a material having a thermal expansion coefficient greater than that of the flexible material layer.

[0020] According to an embodiment, the method may further include heating the flexible material layer and the reinforcing layer to bend the flexible ultrasonic transducer.

[0021] According to one embodiment of the present invention, a flexible ultrasonic transducer having the following structure is provided, namely, capable of simultaneously performing ultrasonic imaging and ultrasonic therapy (for example, utilizing LIFU or HIFU to stimulate or remove lesions), wherein through soft movement, a user can arbitrarily adjust the focal position of the focused ultrasound or improve the focal sensitivity required for ultrasonic imaging and therapy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 1 is a diagram showing a structure of a flexible ultrasonic transducer according to an embodiment.

[0023] Figure 2 This is a diagram showing how a lesion is detected using an ultrasonic probe disposed at the center of a substrate of a flexible ultrasonic transducer according to an embodiment.

[0024] Figure 3A as well as Figure 3B FIG. 1 is a diagram showing a structure of a flexible ultrasonic transducer according to another embodiment.

[0025] Figure 4 FIG. 1 is a diagram showing a cross section of a focused ultrasonic wave output portion disposed on a substrate extension portion of a flexible ultrasonic transducer according to an embodiment.

[0026] Figure 5 This is a diagram showing how the focal position is adjusted by flexible movement of the substrate extension portion of the flexible ultrasonic transducer according to one embodiment.

[0027] 6A to 6F It is a diagram showing a partial process in a method for manufacturing a flexible ultrasonic transducer according to an embodiment.

[0028] Figure 7 This is an electron microscope photograph of the cross-sectional structure of a flexible ultrasonic transducer according to an embodiment. DETAILED DESCRIPTION

[0029] Below, the present invention is described with reference to the accompanying drawings and with reference to the specific embodiments that the present invention can implement as examples. These embodiments are fully described so that those skilled in the art can implement the present invention. Although the various embodiments of the present invention are different, it should be understood that they do not need to be mutually exclusive. For example, the specific shapes, structures and characteristics recorded here can be changed to other embodiments without departing from the concept and scope of the present invention. In addition, it should be understood that the position or configuration of the individual structural elements in the various embodiments disclosed can be changed without departing from the concept and scope of the present invention. Therefore, the detailed description below does not refer to a restrictive meaning. If the scope of the present invention is to be reasonably described, it is limited only by all equivalent scopes required by the scope of the claims and the accompanying scope of the claims. In the accompanying drawings, similar figure marks indicate that the same or similar functions are present in various aspects.

[0030] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings, but the scope of the claimed invention is not limited or restricted by the embodiments.

[0031] Figure 1 1 is a diagram showing a structure of a flexible ultrasonic transducer according to an embodiment.

[0032] Reference Figure 1 The flexible ultrasonic transducer according to one embodiment includes: a substrate having a central portion 10 and a plurality of long extension portions 20 extending from the central portion 10; an ultrasonic probe 100 located at the central portion 10 of the substrate and used to obtain an ultrasonic image of a region of interest; and a focused ultrasonic output portion 200 located at the extension portion 20 of the substrate and configured to output focused ultrasonic waves to the region of interest. The focused ultrasonic output portion 200 located at the extension portion 20 can be easily deformed or restored due to its flexible and elastic properties.

[0033] Figure 2 FIG. 1 is a diagram showing a state in which a lesion is detected using an ultrasonic probe 100 located at the center of a substrate of a flexible ultrasonic transducer according to an embodiment.

[0034] Reference Figure 2 , the ultrasonic probe 100 is composed of an arrangement of multiple imaging ultrasonic output elements 110. Each imaging ultrasonic output element 110 outputs ultrasonic waves toward the region of interest, and the output ultrasonic beam is reflected by an object (e.g., a lesion, a tumor, an organ, etc.) located in the path of travel and returns to the ultrasonic probe 100. The ultrasonic probe 100 detects the position or shape of the object based on the round-trip time information of the ultrasonic wave. The processing device connected to the ultrasonic probe 100 can obtain the position and shape information of the object in real time and visualize it through a display. In this way, the ultrasonic probe is used to detect lesions in the center of the substrate.

[0035] Figure 1 as well as Figure 2 The ultrasonic probe 100 shown in FIG. 1 has a one-dimensional arrangement structure in which a plurality of imaging ultrasonic output elements are arranged in a linear manner. According to one embodiment, the ultrasonic probe with a one-dimensional arrangement structure rotates 360 degrees while taking pictures, thereby obtaining a two-dimensional image (planar image) of the region of interest.

[0036] Figure 3A and 3B is a diagram showing the structure of a flexible ultrasonic transducer according to another embodiment.

[0037] Reference Figure 3A , the ultrasonic probe 100 located at the center portion 10 of the substrate may have a two-dimensional arrangement structure in which a plurality of imaging ultrasonic output elements are arranged in a circular shape. Figure 1 , Figure 2 The one-dimensional arrangement structure of the ultrasonic probe can obtain a two-dimensional image of the area of ​​interest without rotating.

[0038] Reference Figure 3BThe ultrasonic probe 100 disposed at the center portion 10 of the substrate may have a two-dimensional arrangement structure in which a plurality of imaging ultrasonic output elements are arranged in a quadrilateral. Figure 3A Similarly, a two-dimensional image of the region of interest can also be obtained.

[0039] Figure 4 1 is a diagram showing a cross section of a focused ultrasonic wave output portion disposed on a substrate extension portion of a flexible ultrasonic transducer according to an embodiment. Figure 4 Yes Figure 1 FIG. 2 is a cross-sectional view of a portion of the focused ultrasound output portion 200 located on the substrate extension portion 20 along the dashed line AA′.

[0040] Reference Figure 4 The extension portion 20 of the substrate has a plurality of trench structures formed at fixed intervals. The trench structure is filled with a flexible material, such as an elastic polymer including at least one of PDMS (polydimethylsiloxane), polyurethane, polyester, and a mixture thereof, during the manufacturing process of the transducer, and the flexible material layer 220 formed thereby covers the trench structure and the arrangement of the focused ultrasonic output elements 210.

[0041] According to an embodiment, the focused ultrasound output unit 200 may further include a reinforcing layer 230 below the extension portion 20 of the substrate, the reinforcing layer 230 being made of a material having a greater thermal expansion coefficient than the flexible material layer 220. Thus, the bending degree of the element substrate can be adjusted and reinforced.

[0042] Thus, the extension portion 20 of the substrate and the focused ultrasound output portion 200 have a soft structure and can be easily deformed or restored by external pressure. The curvature or elasticity of the substrate can be different according to specific design variables such as the type and content of the material constituting each layer, and the heating temperature in the manufacturing process.

[0043] like Figure 4As shown, the focused ultrasound output elements 210 are arranged at fixed intervals on the extension portion 20 of the substrate. Each focused ultrasound output element 210 is an element that converts AC energy into mechanical vibrations with the same frequency to generate ultrasound, and can be, for example, a micromachined ultrasound transducer such as a CMUT or a PMUT. By adjusting the output according to the part to be treated and the purpose, it is possible to output low-intensity focused ultrasound (LIFU) for stimulating the area of ​​interest with low intensity, or high-intensity focused ultrasound (HIFU) for physically removing lesions in the area of ​​interest. The output ultrasound is superimposed to form an ultrasound beam, and a therapeutic effect is achieved in the body tissue.

[0044] According to one embodiment, the intensity of the high-intensity focused ultrasound is sufficient to apply thermal stimulation or mechanical stimulation to the detected tumor or other lesions to physically remove the lesions. For example, the high-intensity focused ultrasound has a central frequency of more than 1 MHz and a power of 3 W / cm 2 In contrast, low-intensity focused ultrasound has a frequency sufficient to pass through the skull and has an appropriate intensity to physically stimulate human tissue without causing damage to it. For example, low-intensity focused ultrasound has a central frequency of about 200 kHz to 1 MHz and a power of 3 W / cm 2 (Ispta) or less.

[0045] The user can arbitrarily control fine settings such as the frequency, intensity, and switching of thermal / mechanical stimulation types of the ultrasound output from the focused ultrasound output unit 200 through a control device and an interface connected to the ultrasound transducer element.

[0046] Figure 5 This is a diagram showing how the focal distance (focal position) of the flexible ultrasonic transducer according to one embodiment is adjusted by flexible movement.

[0047] like Figure 5 As shown in FIG. 1 , the focused ultrasound output unit 200 located at the extension portion of the substrate has flexibility and can be closely attached to the skin according to the tortuous shape. Figure 5 As shown in (a), each focused ultrasound output element 210 outputs a high-intensity or low-intensity ultrasound beam, and the ultrasound beam focused on the focal point in the region of interest removes or stimulates an object O such as a tumor, cancer cell, lesion, living tissue, etc. Since the focused ultrasound output unit 200 has a flexible characteristic, the user can arbitrarily bend the substrate to adjust the focal distance of the focused ultrasound. For example, Figure 5As shown in (b), if the substrate is greatly bent, the focus on which the ultrasonic beam is focused is located at a closer position.

[0048] In the existing ultrasonic transducer (with a rigid substrate), it is necessary to correct the focal position by controlling the position or phase of each arranged transducer. According to the embodiment of the present invention, the focal distance can be adjusted as desired or the ultrasonic output part can be brought into close contact with the skin according to the tortuosity of the skin by soft movement of the substrate.

[0049] Below, refer to 6A to 6F A method for manufacturing a flexible ultrasonic transducer according to an embodiment will be described.

[0050] First, if Fig. 6A As shown, the step of arranging a plurality of focused ultrasound output elements 610 at fixed intervals on the provided substrate 600 is performed. The substrate 600 may be made of silicon or a mixture of silicon and other substances, but is not limited thereto. The ultrasound output element 610 may be a micromachined ultrasound transducer such as a CMUT or a PMUT, which may output low-intensity focused ultrasound (e.g., having a center frequency of 200 kHz to 1 MHz and a power of 3 W / cm2) for stimulating the area of ​​interest at low intensity according to the part to be treated and the purpose. 2 Ultrasound with an intensity of less than 100 W / cm2 (Ispta) or high-intensity focused ultrasound (with a center frequency of 1 MHz or more and a power of 3 W / cm2) for physically removing lesions in an area of ​​interest 2 (Ultrasound with an intensity above Ispta).

[0051] Next, if Figure 6B As shown, a step of forming a photoresist 615 on each focused ultrasonic output element 610 is performed. Photoresist refers to a photosensitive resin that causes a solidification change when exposed by an exposure device. The photoresist 615 is composed of components that are not decomposed by an etching solution, and protects the focused ultrasonic output element 610 and the substrate 600 thereunder from being etched in subsequent processes.

[0052] Next, if Figure 6C As shown, a step of etching the substrate 600 to form a plurality of thin groove structures between the plurality of focused ultrasonic output elements 610 is performed. According to an embodiment, both wet etching using a chemical solution that reacts with a silicon material substrate or dry etching using an ionized gas can be applied.

[0053] Next, if Fig.6DAs shown, a step of forming a flexible material layer 620 covering the groove structure and the focused ultrasonic output element 610 after removing the photoresist 615 is performed. The flexible material layer 620 is, for example, composed of an elastic polymer including at least one of PDMS (polydimethylsiloxane), polyurethane, polyester, and a mixture thereof. If such a flexible material is filled into the groove structure of the substrate 600, the substrate can achieve soft movement.

[0054] According to one embodiment, Fig. 6E As shown, the following steps may also be performed: a step of forming a reinforcing layer 630 under the substrate 600, the reinforcing layer 630 being composed of a material having a greater thermal expansion coefficient than the flexible material layer 620; and a step of heating the flexible material layer 620 and the reinforcing layer 630. The reinforcing layer 630 may be composed of a material having a greater thermal expansion coefficient than PDMS constituting the flexible material layer 620, such as polyparaxylene (plastic obtained by polymerizing paraxylene).

[0055] Thus, since the volume increase rate of the reinforcing layer 630 having a larger thermal expansion coefficient than the flexible material layer 620 is larger, the curvature of the element can be increased. Fig. 6F As shown, the substrate is bent toward the surface opposite to the surface formed with the reinforcing layer 630. The degree of substrate bending or elastic force may vary depending on the type and content of the constituent materials constituting the flexible material layer 620 and / or the reinforcing layer 630, and the degree of heating during the manufacturing process.

[0056] Figure 7 FIG. 1 is an electron microscope photograph of the cross-sectional structure of a flexible ultrasonic transducer according to an embodiment. Figure 7 As shown, ultrasonic transducer elements are arranged on a substrate, and a groove structure is formed between every two ultrasonic transducer elements and then filled with a flexible material, thereby manufacturing a flexible ultrasonic transducer element that can adhere to the skin or change the focal position by soft movement.

[0057] According to the above-mentioned embodiment, a dual-mode ultrasonic transducer is provided that can obtain an ultrasonic image through an ultrasonic probe at the center and can perform ultrasonic treatment (stimulate or remove lesions) using focused ultrasound with the flexible extension portion in close contact with the skin.

[0058] The existing dual-mode ultrasonic transducer has the disadvantages of being large and heavy in weight, as the high-frequency output part for ultrasonic imaging and the low-frequency output part for ultrasonic therapy are independently manufactured and then combined. According to the present invention, there is no need to assemble a conversion part separately, and the transducer elements can be arranged in different ways on each substrate (central part, extension part) to design different response characteristics of the frequency required for treatment and the frequency required for imaging. Therefore, the manufacturing cost can be reduced, and the volume and weight of the elements can be reduced.

[0059] In addition, in the prior art, the complexity of the process is solved by arranging the CMUT elements in a uniform manner, but according to an embodiment of the present invention, its advantage is that it can not only solve the complexity of the process by arranging the 1D array and 2D array of CMUT on each substrate, but also maximize the effect of the ultrasonic transducer.

[0060] In the prior art, in order to adjust the focal length, a mechanical connection device is included to allow the tilting movement of the transducer array through an independent time delay. According to the embodiments of the present invention, the focus sensitivity required for ultrasound imaging and treatment can be further improved through the soft movement of the flexible substrate of the transducer element itself.

[0061] As a result, there is no need to provide a separate drive unit to move the focus of the focused ultrasound. By adding a flexible material layer to the existing substrate, the focus of the target area can be directly adjusted as a CMUT sensor. Therefore, the function of the transducer can be maximized without adding other components.

[0062] Although the above description is made with reference to the embodiments, it should be understood that those skilled in the art can modify and alter the present invention in various ways without departing from the concept and scope of the present invention as described in the appended claims.

Claims

1. A flexible ultrasonic transducer, characterized in that: include: a base plate having a shape having a central portion and a plurality of long extensions extending from the central portion; an ultrasonic probe located at a central portion of the substrate and used to obtain an ultrasonic image of a region of interest; and A plurality of focused ultrasonic wave output parts, which are located in the plurality of extension parts and are configured to output focused ultrasonic waves to the region of interest, each of the plurality of focused ultrasonic wave output parts comprises: an arrangement of a plurality of focused ultrasonic wave output elements, wherein each of a plurality of groove structures is formed between the plurality of focused ultrasonic wave output elements; and a flexible material layer, the flexible material layer is filled in the plurality of groove structures and covers the plurality of groove structures and the arrangement of the plurality of focused ultrasonic wave output elements, wherein: Each of the plurality of extensions comprises a reinforcing layer disposed on a side of the substrate opposite to the plurality of focused ultrasonic output portions, the reinforcing layer being composed of a material having a thermal expansion coefficient greater than that of the flexible material layer; wherein, The extension portion of the substrate and the focused ultrasonic wave output portion have flexibility and are deformable.

2. The flexible ultrasonic transducer according to claim 1, characterized in that: The ultrasonic probe includes an array of a plurality of imaging ultrasonic wave output elements configured to output imaging ultrasonic waves toward the region of interest.

3. The flexible ultrasonic transducer according to claim 2, characterized in that: The ultrasonic probe includes the plurality of imaging ultrasonic output elements arranged in a linear one-dimensional arrangement or the plurality of imaging ultrasonic output elements arranged in a planar two-dimensional arrangement.

4. The flexible ultrasonic transducer according to claim 1, characterized in that: The plurality of focused ultrasound output elements are arranged to output therapeutic focused ultrasound to the region of interest.

5. The flexible ultrasonic transducer according to claim 4, characterized in that: The therapeutic focused ultrasound is low-intensity focused ultrasound for stimulating the region of interest at a low intensity or high-intensity focused ultrasound for removing a lesion in the region of interest.

6. The flexible ultrasonic transducer according to claim 1, characterized in that: The ultrasonic probe or the focused ultrasonic output section includes an ultrasonic output element that is a micromachined ultrasonic transducer.

7. A method for manufacturing a flexible ultrasonic transducer, characterized in that: include: providing a substrate; The step of arranging a plurality of focused ultrasonic output elements at fixed intervals on the substrate; forming a photoresist on the plurality of focused ultrasonic output elements; A step of etching the substrate to form a plurality of groove structures between the plurality of focused ultrasonic output elements; forming a flexible material layer filled in the plurality of groove structures and covering the plurality of groove structures and the plurality of focused ultrasound output elements; and A step of forming a reinforcement layer below the substrate, wherein the reinforcement layer is made of a material having a thermal expansion coefficient greater than that of the flexible material layer.

8. The method for manufacturing a flexible ultrasonic transducer according to claim 7, characterized in that: The focused ultrasonic output element is a micromachined ultrasonic transducer.

9. The method for manufacturing a flexible ultrasonic transducer according to claim 7, characterized in that: The flexible material layer is made of an elastic polymer including at least one of polydimethylsiloxane, polyurethane, polyester fiber and a mixture thereof.

10. The method for manufacturing a flexible ultrasonic transducer according to claim 7, characterized in that: The method also includes the step of heating the flexible material layer and the reinforcing layer to bend the flexible ultrasonic transducer.

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