Ultrasonic wave unit, diffraction swelling tape, and ultrasonic wave focusing device

Abstract

The ultrasonic wave unit according to the present invention comprises a piezoelectric element having an ultrasonic wave generation surface for generating ultrasonic waves and a transmissive diffraction portion which is positioned on the ultrasonic wave generation surface or is positioned apart from the ultrasonic wave generation surface.

Description

Ultrasonic unit, diffractive swelling tape, and ultrasonic focusing device

[0001] The present invention relates to an ultrasound unit, a diffractive swelling tape, and an ultrasound focusing device. This application claims priority to Japanese Patent Application No. 2022-055687, filed on March 30, 2022, the contents of which are incorporated herein by reference.

[0002] For example, as disclosed in Patent Document 1, a focused acoustic therapy device is known that includes a planar element that generates ultrasound waves and an acoustic lens that allows the ultrasound waves to pass through. In such a focused acoustic therapy device, sound waves are generated with an acoustically transparent gel and an acoustic lens interposed between the planar element and the skin surface. This makes it possible to focus the energy of the sound waves at a treatment site located at a desired depth from the skin surface.

[0003] The acoustic lens has a concave surface located on the opposite side to the surface attached to the planar element. The concave surface has a spherical surface designed based on a curvature corresponding to the focal distance from the skin to the treatment site. The focal distance can be adjusted by adjusting the curvature of the concave surface.

[0004] Utility Model Registration No. 3216192

[0005] However, in the configuration of the above-mentioned focused acoustic therapy device, it is necessary to form a concave portion on the acoustic lens. It is difficult to process a spherical surface with a high degree of curvature into a concave portion, and it is difficult to reduce the processing cost. Therefore, there is a problem that an acoustic lens with a concave portion is not suitable for mass production.

[0006] The present invention has been made in consideration of the above problems, and aims to provide an ultrasonic unit, a diffractive swelling tape, and an ultrasonic focusing device that have a structure that is easy to process, thereby reducing processing costs.

[0007] An ultrasonic unit according to one aspect of the present invention includes a piezoelectric element having an ultrasonic generating surface that generates ultrasonic waves, and a transmissive diffraction section that is located on the ultrasonic generating surface or spaced apart from the ultrasonic generating surface.

[0008] In the ultrasonic unit according to one aspect of the present invention, the transmission type diffraction section may be located on the ultrasonic wave generating surface, and the transmission type diffraction section may be a member different from the piezoelectric element.

[0009] The ultrasound unit according to one aspect of the present invention may further include a swelling body provided on the ultrasound generating surface so as to cover the transmission type diffraction section.

[0010] In an ultrasonic unit according to one aspect of the present invention, the transmissive diffraction section is positioned at a distance from the ultrasonic wave generating surface, and the transmissive diffraction section has a first surface facing the ultrasonic wave generating surface at a distance from the ultrasonic wave generating surface, and a second surface opposite the first surface, and a swelling body is disposed at least between the ultrasonic wave generating surface and the first surface, and the swelling body may adhere at least the transmissive diffraction section to the piezoelectric element.

[0011] In the ultrasound unit according to one aspect of the present invention, the swollen body may adhere the transmission type diffraction section to the piezoelectric element so as to cover both the first surface and the second surface.

[0012] In an ultrasonic unit according to one aspect of the present invention, the swelling body may include a first swelling body located between the ultrasonic wave generating surface and the first surface, which adheres the transmission type diffraction section to the piezoelectric element, and a second swelling body which is detachable from the second surface.

[0013] In an ultrasonic unit according to one aspect of the present invention, the swollen body has a contact surface that contacts the ultrasonic generating surface and an exposed surface that is on the opposite side of the contact surface and is exposed to the outside of the ultrasonic unit, and in the direction from the contact surface toward the exposed surface, the swollen body located between the first surface and the contact surface has a first thickness, and the swollen body located between the second surface and the exposed surface has a second thickness, and by adjusting at least one of the first thickness and the second thickness, it is possible to adjust the focal length from the exposed surface to the focal point or the focusing rate of the ultrasonic waves.

[0014] In an ultrasonic unit according to one aspect of the present invention, the swollen body has a contact surface that contacts the ultrasonic wave generating surface and an exposed surface that is on the opposite side of the contact surface and is exposed to the outside of the ultrasonic unit, and the transmissive diffraction section has a slit, and by adjusting the width of the slit, the focal distance from the exposed surface to the focal point or the focusing rate of the ultrasonic waves may be adjusted.

[0015] In an ultrasonic unit according to one aspect of the present invention, the transmissive diffraction section may have a first member, a second member spaced apart from the first member and surrounding the first member, and a connecting section located between the first member and the second member and connecting the first member and the second member.

[0016] A diffractive swelling tape according to one aspect of the present invention is used in the ultrasound unit according to the above aspect, and includes a transmission-type diffractive section having a first surface and a second surface opposite to the first surface, and a swelling body covering at least one of the first surface and the second surface and being adhered to a piezoelectric element.

[0017] An ultrasonic focusing device according to one aspect of the present invention comprises an ultrasonic unit, a signal generating unit that supplies a frequency signal to the ultrasonic unit, and an AC voltage generating unit that supplies an AC voltage to the signal generating unit, wherein the ultrasonic unit comprises a piezoelectric element having an ultrasonic generating surface that generates ultrasonic waves, and a transmission type diffraction unit that is located on the ultrasonic generating surface or is located away from the ultrasonic generating surface.

[0018] The ultrasonic unit, diffractive swelling tape, and ultrasonic focusing device according to the aspects of the present invention have a structure that is easy to process, thereby reducing processing costs.

[0019] FIG. 1 is a functional block diagram showing an example of the configuration of an ultrasonic focusing device according to a first embodiment of the present invention; FIG. 2 is a schematic cross-sectional view partially showing the structure of an ultrasonic unit according to a first embodiment of the present invention, as viewed from a direction parallel to the ultrasonic unit; FIG. 3 is a schematic cross-sectional view partially showing the structure of an ultrasonic unit according to a first embodiment of the present invention, as viewed from a thickness direction of the ultrasonic unit; FIG. 4 is a schematic cross-sectional view partially showing a modified example of an FZP member constituting the ultrasonic unit according to the first embodiment of the present invention, as viewed from a thickness direction of the ultrasonic unit; FIG. 5 is a schematic cross-sectional view partially showing the structure of an ultrasonic unit according to a second embodiment of the present invention, as viewed from a direction parallel to the ultrasonic unit; FIG. 6 is a schematic cross-sectional view partially showing the structure of an ultrasonic unit according to a third embodiment of the present invention, as viewed from a direction parallel to the ultrasonic unit; FIG. 7 is a schematic cross-sectional view partially showing the structure of an ultrasonic unit according to a fourth embodiment of the present invention, as viewed from a direction parallel to the ultrasonic unit; FIG. 8 is a schematic cross-sectional view partially showing the structure of an ultrasonic unit according to a fifth embodiment of the present invention, as viewed from a direction parallel to the ultrasonic unit; FIG. 9 is a schematic cross-sectional view partially showing the structure of a diffractive gel tape according to a sixth embodiment of the present invention, as viewed from a direction parallel to the diffractive gel tape; and FIG. 10 is a plan view partially showing a modified example of a diffractive gel tape according to the sixth embodiment of the present invention. 10 is a schematic cross-sectional view partially showing the structure of a diffractive gel tape according to a modified example of the seventh embodiment of the present invention, as viewed from a direction parallel to the diffractive gel tape; FIG. 11 is a schematic cross-sectional view partially showing the structure of a diffractive gel tape according to the seventh embodiment of the present invention, as viewed from a direction parallel to the diffractive gel tape; FIG. 12 is a schematic cross-sectional view partially showing the structure of a diffractive gel tape according to the seventh embodiment of the present invention, as viewed from a direction parallel to the diffractive gel tape; FIG. 13 is a schematic cross-sectional view partially showing the structure of a diffractive gel tape according to the seventh embodiment of the present invention, as viewed from a direction parallel to the diffractive gel tape; FIG. 14 is a schematic cross-sectional view partially showing the structure of a diffractive gel tape according to a modified example of the seventh embodiment of the present invention, as viewed from a direction parallel to the diffractive gel tape; FIG. 15 is a schematic cross-sectional view partially showing the structure of a diffractive gel tape according to a modified example of the seventh embodiment of the present invention, as viewed from a direction parallel to the diffractive gel tape; FIG. 16 is a schematic cross-sectional view partially showing the structure of a diffractive gel tape according to a modified example of the seventh embodiment of the present invention, as viewed from a direction parallel to the diffractive gel tape;1 is a cross-sectional view schematically showing an ultrasonic unit according to an example of the present invention, and is a view for explaining the conditions of a simulation. FIG. 2 is a cross-sectional view schematically showing an ultrasonic unit according to Example 1 of the present invention, and is a view for explaining an analytical model of the simulation. FIG. 3 is a view showing the results of a simulation of an ultrasonic unit according to Example 1 of the present invention. FIG. 4 is a view showing the results of a simulation of an ultrasonic unit according to Example 1 of the present invention. FIG. 5 is a cross-sectional view schematically showing an ultrasonic unit of a comparative example, and is a view for explaining the conditions of the simulation. FIG. 6 is a cross-sectional view schematically showing an ultrasonic unit of a comparative example, and is a view for explaining an analytical model of the simulation. FIG. 7 is a view showing the results of a simulation of an ultrasonic unit of a comparative example. FIG. 8 is a view showing the results of a simulation of an ultrasonic unit according to Example 2 of the present invention. FIG. 9 is a view showing the results of a simulation of an ultrasonic unit according to Example 2 of the present invention. FIG. 10 is a view showing the results of a simulation of an ultrasonic unit according to Example 2 of the present invention. FIG. 11 is a view showing the results of a simulation of an ultrasonic unit according to Example 2 of the present invention. FIG. 12 is a view showing the results of a comparison between the present invention and a comparative example in terms of maximum ultrasonic intensity, with respect to Example 3 of the present invention. FIG. 13 is a table showing the conditions of Example 4 of the present invention. FIG. 14 is a view showing the configuration of a test apparatus used in Example 4 of the present invention. FIG. 15 is a view showing the results of a simulation of a comparative example with respect to Example 4 of the present invention. FIG. 16 is a view showing the results of an experiment of a comparative example using a test apparatus, with respect to Example 4 of the present invention. FIG. 10 is a diagram showing a simulation result of lens 1 in Example 4 of the present invention. FIG. 11 is a diagram showing an experimental result of lens 1 using a test device in Example 4 of the present invention. FIG. 12 is a diagram showing a simulation result of lens 2 in Example 4 of the present invention. FIG. 13 is a diagram showing an experimental result of lens 2 using a test device in Example 4 of the present invention. FIG. 14 is a diagram showing a simulation result of a comparative example in Example 4 of the present invention. FIG. 15 is a diagram showing an experimental result of a comparative example using a test device in Example 4 of the present invention. FIG. 16 is a diagram showing a simulation result of lens 3 in Example 4 of the present invention. FIG. 17 is a diagram showing an experimental result of lens 3 using a test device in Example 4 of the present invention.10 is a diagram showing a simulation result of Lens 4 in Example 4 of the present invention; 11 is a diagram showing an experimental result of Lens 4 using a test device in Example 4 of the present invention; 12 is a table summarizing the simulation results and experimental results of Lenses 1 to 4 in Example 4 of the present invention.

[0020] An ultrasonic unit, a diffractive swelling tape, and an ultrasonic focusing device according to an embodiment of the present invention will be described with reference to the drawings. In the description of the embodiments, components having the same or similar functions are assigned the same reference numerals. Duplicate descriptions of components may be omitted. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. may not necessarily be the same as those in reality.

[0021] In the description of the embodiments, ordinal numbers such as "first" and "second" may be used. These ordinal numbers do not indicate the number of components described by the ordinal numbers. Ordinal numbers may be used to indicate that each of a plurality of components is a separate component.

[0022] In the drawings referred to in the description of the embodiments, three directions corresponding to a three-dimensional Cartesian coordinate system, namely, the X direction, the Y direction, and the Z direction, are shown (symbols X, Y, and Z). The Z direction corresponds to the thickness direction of the ultrasound unit, or the direction from the contact surface of the gel member toward the exposed surface. In other words, the Z direction corresponds to the direction in which ultrasound generated from the piezoelectric element propagates toward the swelling body. Of the two directions perpendicular to the Z direction, one is referred to as the X direction, and the other is referred to as the Y direction. The X direction and the Y direction may also be referred to as directions parallel to the ultrasound unit or directions parallel to the diffractive gel tape. When viewed in the Z direction, the direction extending radially from the center of the ultrasound unit is referred to as the radial direction. When viewed in the Z direction, the circumferential direction of a circular ultrasound unit is referred to as the circumferential direction.

[0023] However, the terms "X direction," "Y direction," and "Z direction" are used to describe the relative positions of the multiple components that make up the ultrasound unit and the shapes and structures of each of the multiple components, and do not define the orientation of the ultrasound unit. Depending on the usage state of the ultrasound unit, the orientation of the ultrasound unit can change freely. In such usage state, for example, the ultrasound unit may be inverted or tilted in at least one of the three directions.

[0024] In the following embodiments, the ultrasound unit, diffractive gel tape, and ultrasound focusing device are applied to, for example, an acupuncture point stimulation device. Such an acupuncture point stimulation device utilizes the ultrasound focusing effect to non-invasively (without damaging the body) stimulate a treatment site (focus) located at a desired depth below the skin surface of a living body, such as a human or animal. This ultrasound stimulation can thus achieve the same effect as acupuncture.

[0025] <First Embodiment> <Structure of Ultrasonic Focusing Device> Fig. 1 is a functional block diagram showing an example of the configuration of an ultrasonic focusing device 200. The ultrasonic focusing device 200 includes an ultrasonic unit 1, a device main body 100, and a signal cable 103. The device main body 100 includes an AC voltage generating section 101 and a signal generating section 102. The ultrasonic unit 1 is electrically connected to the signal generating section 102 of the device main body 100 via the signal cable 103. The ultrasonic unit 1 generates ultrasonic waves based on a frequency signal received from the signal generating section 102.

[0026] When using the ultrasonic focusing device 200, the ultrasonic focusing device 200 is connected to an external power supply via a power cable (not shown). The external power supply is, for example, a commercial power supply that supplies power to a power outlet. The power of the external power supply is, for example, AC power such as AC 100 V. In this case, it is possible to realize the ultrasonic focusing device 200 that uses the external power supply.

[0027] Instead of using an external power supply, the ultrasonic focusing device 200 may be provided with a rechargeable battery. In this case, it is not necessary to connect the external power supply to the ultrasonic focusing device 200, and a portable ultrasonic focusing device 200 that uses power stored in the battery can be realized. In the following description, an ultrasonic focusing device 200 that uses an external power supply will be described.

[0028] <AC voltage generating unit 101> The AC voltage generating unit 101 is connected to the signal generating unit 102 via wiring built into the ultrasonic focusing device 200. The AC voltage generating unit 101 is configured to supply an AC voltage to the signal generating unit 102. The AC voltage generating unit 101 is a circuit configured to boost AC power supplied from an external power supply to the ultrasonic focusing device 200. The AC voltage generating unit 101 includes, for example, a transformer and an inverter. As long as the AC voltage can be supplied to the signal generating unit 102, the circuit configuration of the AC voltage generating unit 101 is not limited, and a known circuit may be used. The AC voltage generating unit 101 may also be referred to as a power amplifier.

[0029] <Signal Generating Unit 102> The signal generating unit 102 is connected to the ultrasound unit 1 via a signal cable 103. The signal generating unit 102 is a circuit configured to supply a frequency signal to the ultrasound unit 1. With regard to the frequency signal, there are no particular limitations on the frequency value, signal waveform, voltage value, etc., as long as the effect of the ultrasound unit 1 can be sufficiently obtained.

[0030] The frequency signal may be, for example, a continuous wave having a frequency that matches the design value of the FZP member 20, which will be described later. Examples of such continuous waves include sine waves and burst waves. The frequency signal supplied by the signal generating unit 102 to the ultrasound unit 1 is not limited to sine waves and burst waves, and signals having other waveforms may also be used. For example, a signal having an ultrasound pulse waveform may also be used.

[0031] The circuit configuration of the signal generating unit 102 is not limited, and a known circuit may be used as long as it can supply a continuous wave, which is a frequency signal, to the ultrasound unit 1. The signal generating unit 102 may also be called an AC waveform generator.

[0032] <Ultrasound unit 1> Fig. 2 is a schematic cross-sectional view partially showing the structure of the ultrasound unit 1 according to the first embodiment, as viewed from a direction parallel to the ultrasound unit 1. Fig. 3A is a schematic cross-sectional view partially showing the structure of the ultrasound unit 1 according to the first embodiment, as viewed from the thickness direction of the ultrasound unit 1.

[0033] 2 and 3A, the ultrasound unit 1 includes a piezoelectric element 10, a Fresnel Zone Plate (FZP) member 20, and a gel member 30. The FZP member 20 is an example of a transmission type diffraction section. The gel member 30 is an example of a swelling body.

[0034] The shape of the ultrasound unit 1 is circular when viewed in the Z direction. However, the shape of the ultrasound unit 1 may be a shape other than circular. The width of the ultrasound unit 1 in the X and Y directions, i.e., the diameter of the ultrasound unit 1, is, for example, approximately 5 mm to 6 mm. However, this embodiment does not limit the diameter of the ultrasound unit 1. The length of the ultrasound unit 1 in the Z direction, i.e., the thickness of the ultrasound unit 1, can be changed as appropriate depending on the thickness of the FZP member 20 and the gel member 30 that constitute the ultrasound unit 1.

[0035] 2 and 3A, the ultrasound unit 1 includes the gel member 30, but the ultrasound unit 1 does not necessarily have to include the gel member 30. That is, the ultrasound unit 1 only needs to include at least the piezoelectric element 10 and the FZP member 20. Regarding the positional relationship between the piezoelectric element 10 and the FZP member 20 in the ultrasound unit 1, the piezoelectric element 10 and the FZP member 20 are spaced apart in the structure shown in FIG. 2, but the piezoelectric element 10 does not necessarily have to be spaced apart from the FZP member 20. In other words, the FZP member 20 may be positioned on the piezoelectric element 10 so as to be in contact with the piezoelectric element 10. Furthermore, in the example shown in FIGS. 2 and 3A, the FZP member 20 is made of a different material from the piezoelectric element 10.

[0036] <Piezoelectric element 10> The piezoelectric element 10 is a passive element that utilizes the piezoelectric effect. Specifically, the piezoelectric element 10 includes an upper electrode, a lower electrode, and a piezoelectric body sandwiched between the upper and lower electrodes. The voltage of a frequency signal supplied to the piezoelectric element 10 from the signal generating unit 102 is applied to the upper and lower electrodes. The voltage of the frequency signal applied between the upper and lower electrodes is applied to the piezoelectric body, causing it to vibrate. In other words, the piezoelectric element 10 is configured to convert a voltage signal applied to the piezoelectric element 10 into vibrational motion.

[0037] The piezoelectric body is formed using a ferroelectric ceramic such as PZT (lead zirconate titanate). The material constituting the piezoelectric body is not limited to PZT, and other piezoelectric element materials may be used.

[0038] The structure of the piezoelectric element 10 is not particularly limited. The piezoelectric element 10 may include, for example, a lower electrode, an upper electrode, and a support substrate that supports the piezoelectric body. The support substrate may have a wiring pattern connected to each of the lower electrode and the upper electrode. In this case, the signal cable 103, the lower electrode, and the upper electrode are connected via the wiring pattern formed on the support substrate. In the example shown in FIGS. 2 and 3A , the piezoelectric element 10 has a shape similar to that of the ultrasound unit 1 when viewed in the Z direction, but the shape of the piezoelectric element 10 is not particularly limited. In terms of reducing the manufacturing cost of the ultrasound unit 1, it is preferable that the piezoelectric element 10 be a commercially available product that has been in the market for some time.

[0039] The piezoelectric element 10 has an ultrasonic wave generating surface 10F that generates ultrasonic waves. The ultrasonic wave generating surface 10F is, for example, the surface of one of the upper electrode and the lower electrode that constitute the piezoelectric element 10. Note that the ultrasonic wave generating surface 10F does not have to be the surface of one of the upper electrode and the lower electrode. As long as the vibration of the piezoelectric element 10 can be transmitted to the ultrasonic wave generating surface 10F and the ultrasonic wave generating surface 10F can generate ultrasonic waves, the position of the ultrasonic wave generating surface 10F in the structure of the piezoelectric element 10 is not limited. For example, the ultrasonic wave generating surface 10F may be formed in a portion located inside an electrode that is formed in a ring shape when viewed in the Z direction.

[0040] In this embodiment, the ultrasonic wave generating surface 10F is the surface that comes into contact with the gel member 30 and is the surface from which the gel member 30 is peeled off. The ultrasonic wave generating surface 10F of a commercially available piezoelectric element 10 is, for example, a flat surface. The structure and shape of the ultrasonic wave generating surface 10F are not particularly limited. The surface of the ultrasonic wave generating surface 10F may be an uneven surface that takes into consideration the adhesive strength between the ultrasonic wave generating surface 10F and the gel member 30 and the ease of peeling the gel member 30 from the ultrasonic wave generating surface 10F. In this case, for example, the ultrasonic wave generating surface 10F may have an uneven surface on which fine irregularities are formed. In other words, the ultrasonic wave generating surface 10F may have a surface roughness that takes into consideration the adhesive strength to the gel member 30 and the ease of peeling.

[0041] The shape of the ultrasonic wave generating surface 10F of the piezoelectric element 10 is not limited to a flat surface, and may be curved or uneven. The piezoelectric element 10 may also be a flexible piezoelectric element. For example, a structure using a flexible film can be adopted as a flexible piezoelectric element.

[0042] <FZP member 20> The FZP member 20 is a flat member having a slit 25. The FZP member 20 is an example of an acoustic lens. In this embodiment, the FZP member 20 has an inner FZP portion 21 and an outer FZP portion 22. The outer FZP portion 22 is positioned so as to surround the inner FZP portion 21. The inner FZP portion 21 and the outer FZP portion 22 are spaced apart from each other. A slit 25 is formed between the inner FZP portion 21 and the outer FZP portion 22. The inner FZP portion 21 is an example of a first member. The outer FZP portion 22 is an example of a second member.

[0043] In other words, the FZP member 20 has a concentric slit pattern SP formed in a flat plate member. Specifically, the slit pattern SP has a central opening P1 and a peripheral opening P2. The central opening P1 is circular in shape. The peripheral opening P2 is annular in shape. The peripheral opening P2 is positioned so as to surround the central opening P1. The central opening P1 and the peripheral openings P2 are positioned concentrically. The FZP member 20 is a member that generates diffraction of ultrasound waves by the concentric slit pattern SP.

[0044] The FZP member 20 functions as a lens that generates interference of ultrasonic waves, resulting in a diffraction phenomenon (Fresnel diffraction), and generates ultrasonic interference fringes at a focal point. Therefore, the FZP member 20 can also be referred to as a diffraction member, a diffraction lens, an FZP lens, a Fresnel lens, or the like. In the ultrasonic unit 1 using the FZP member 20, the focal length can be adjusted depending on the frequency of the ultrasonic waves. In other words, the configuration of the FZP member 20 can be adjusted depending on the frequency signal supplied from the ultrasonic focusing device 200 to the piezoelectric element 10 and the frequency of the ultrasonic waves generated by the piezoelectric element 10.

[0045] In the following description, the term "focal point" refers to the position where ultrasonic waves are focused. In other words, the focal point corresponds to the treatment area in the depth direction from the skin of the living body. Furthermore, the term "focal length" corresponds to the distance from the end of the ultrasonic unit 1 in the Z direction to the focal point. In other words, the term "focal length" corresponds to the distance between the exposed surface 30S of the gel member 30 and the focal point, i.e., the distance between the surface of the skin of the living body and the treatment area.

[0046] For example, acrylic resin (PMMA, Polymethyl Methylacrylate) is used as the material of the flat plate member that constitutes the FZP member 20. Note that the FZP member 20 may be made of a material other than acrylic resin.

[0047] The thickness of the FZP member 20 in the Z direction is set to a value approximately equal to the wavelength of the ultrasonic waves propagating through the gel member 30. The wavelength λ is calculated by dividing the propagation velocity v by the frequency f (λ = v / f). The propagation velocity of the ultrasonic waves propagating through the gel member 30 used in this embodiment is 1141.5 m / s. In this case, if the frequency of the ultrasonic waves is 2 MHz, the wavelength of the ultrasonic waves is 570.75 μm, and the thickness of the FZP member 20 is set to approximately 0.6 mm. If the frequency of the ultrasonic waves is 3 MHz, the wavelength of the ultrasonic waves is 380.5 μm, and the thickness of the FZP member 20 is set to approximately 0.4 mm.

[0048] The FZP member 20 is located at a distance from the ultrasonic generating surface 10F. Specifically, the FZP member 20 has a first FZP surface 20F facing the ultrasonic generating surface 10F at a distance, and a second FZP surface 20S on the opposite side of the first FZP surface 20F. The first FZP surface 20F is an example of a first surface. The second FZP surface 20S is an example of a second surface.

[0049] The slits 25 in the FZP member 20 are portions that allow the ultrasonic waves generated by the piezoelectric element 10 to pass through. In other words, ultrasonic waves do not pass through portions of the FZP member 20 where the slits 25 are not formed. The width of the slits 25 in the radial direction is determined depending on the focal length or ultrasonic focusing rate when using the ultrasonic unit 1. The width of the slits 25 is selected, for example, from a range of 0.4 mm to 1.0 mm. However, this embodiment does not limit the width of the slits 25. Methods for forming the slits 25 in the flat plate member that serves as the base material for the FZP member 20 include, for example, laser processing, cutting, etching, etc. As long as the desired width of the slits 25 can be ensured, high precision is not required for processing the slits 25.

[0050] 2, the FZP member 20 is disposed so as to be spaced apart from the ultrasonic generating surface 10F, but the FZP member 20 does not have to be spaced apart from the ultrasonic generating surface 10F. In other words, the FZP member 20 may be in contact with the ultrasonic generating surface 10F. That is, the FZP member 20 may be located on the ultrasonic generating surface 10F or may be located spaced apart from the ultrasonic generating surface 10F.

[0051] <First Modification of FZP Member 20> Figure 3B is a schematic cross-sectional view partially illustrating a modification of the FZP member 20 constituting the ultrasound unit 1A according to the first embodiment, as viewed from the thickness direction of the ultrasound unit 1A. The FZP member 20 shown in Figure 3B differs from the FZP member 20 shown in Figure 3A in that a connecting portion is provided between the inner FZP portion 21 and the outer FZP portion 22.

[0052] As shown in FIG. 3B , the FZP member 20 has connecting portions 23 that connect the inner FZP portion 21 and the outer FZP portion 22. The connecting portions 23 extend, for example, along the radial direction. The connecting portions 23 may extend in a direction inclined toward the radial direction. In the example shown in FIG. 3B , the number of connecting portions 23 is four, but the number of connecting portions 23 may be one to three, or may be five or more. For example, the number of connecting portions 23 can be determined depending on the strength required of the FZP member 20.

[0053] In the example shown in FIG. 3B , the slit pattern SP has one central opening P1 and multiple peripheral openings P2. Since there are four connecting portions 23, there are also four peripheral openings P2. The four peripheral openings P2 are aligned along the circumferential direction. Each of the four peripheral openings P2 is a curved elongated hole. This elongated hole has a curved shape that extends along the circumferential direction. The four peripheral openings P2 are positioned to surround the central opening P1. The central opening P1 and the four peripheral openings P2 are positioned concentrically. Two adjacent peripheral openings P2 are spaced apart in the circumferential direction. In other words, the four peripheral openings P2 may be referred to as an annular shape having a spaced apart portion formed by the connecting portions 23.

[0054] Because the inner FZP portion 21 and the outer FZP portion 22 are connected by the connecting portion 23, the inner FZP portion 21 and the outer FZP portion 22 can be integrated, thereby improving the strength of the FZP member 20. Furthermore, the connecting portion 23 allows the distance between the inner FZP portion 21 and the outer FZP portion 22, i.e., the width of the slit 25, to be maintained constant.

[0055] 3A and 3B, the slit pattern SP of the FZP member 20 is a concentric circular pattern, but the slit pattern SP is not limited to a concentric circular pattern. The FZP member 20 may have a slit pattern SP that extends linearly in the X direction, the Y direction, or a diagonal direction oblique to the X direction. In other words, the FZP member 20 may have a diffraction grating with a line-and-space pattern. Furthermore, a spiral pattern may be adopted as the slit pattern SP of the FZP member 20.

[0056] 3A and 3B, the central opening P1 has a circular shape. However, other shapes may be used for the central opening P1. For example, the central opening P1 may have an elongated hole shape or an elliptical shape. As long as a constant slit width can be obtained, the annular shape formed by one or more peripheral openings P2 may be changed depending on the shape of the central opening P1.

[0057] Furthermore, the FZP member 20 may have a hologram element, in other words, a holographic diffraction grating, as long as it can generate the diffraction interference effect of ultrasonic waves. The FZP member 20 may perform ultrasonic beam forming, ultrasonic collimation, and ultrasonic modulation.

[0058] <Selection from Multiple FZP Members> It is also possible to prepare multiple types of FZP members with different slit 25 widths, i.e., N types (N is an integer greater than or equal to 2), of FZP members. Specifically, multiple types of FZP members are first designed according to the type of treatment target, type of treatment region, type of focal length, or type of ultrasonic focusing rate. In designing multiple FZP members, the width of the slit 25 is freely selected, and experiments and simulations are performed for each slit 25 to determine the width of the slit 25 according to the type of treatment target, type of treatment region, type of focal length, or type of ultrasonic focusing rate. In other words, by performing experiments and simulations while adjusting the width of the slit 25, the slit 25 according to the treatment target, type of treatment region, type of focal length, or type of ultrasonic focusing rate can be determined.

[0059] Through the above preparation, multiple types of FZP members having different widths of slits 25 can be obtained. The phrase "different widths of slits 25" means that the widths of the slits 25 in each of the multiple types of FZP members are different from each other. Note that when designing the FZP member, not only the width of the slits 25 but also the slit pattern SP may be designed. Different slit patterns SP may be designed.

[0060] The method for selecting an FZP member having an appropriate slit 25 from among a plurality of FZP members is as follows: Here, the "FZP member having an appropriate slit 25" is an FZP member to be used in actual treatment, and is selected by the user of the ultrasound unit 1 in consideration of the target treatment object, the target treatment area, the target focal length, or the target ultrasonic focusing rate.

[0061] The user determines the target treatment object, the target focal length, or the target ultrasonic focusing ratio. Next, the user selects an FZP member having an appropriate slit 25 from among a plurality of types of FZP members according to the target treatment object, the target focal length, or the target ultrasonic focusing ratio. The selected FZP member is applied to the ultrasonic unit 1. Therefore, by selecting an appropriate FZP member from a plurality of FZP members, it is possible to adjust the focal length or ultrasonic focusing ratio in the ultrasonic unit 1. In other words, by adjusting the width of the slit 25, it is possible to adjust the focal length or ultrasonic focusing ratio.

[0062] <Gel Member 30> The gel member 30 is a member in a gel state containing a solid polymer and a solvent such as water. In other words, the gel member 30 is a member that can be elastically deformed. The gel member 30 has a structure in which the volume increases as the solid polymer absorbs the solvent.

[0063] The flat plate members constituting the gel member 30 are made of, for example, urethane resin. The density of the gel member 30 is approximately 998.6 kg / m ３ It should be noted that materials other than urethane resin may be used as the material of the gel member 30. It is preferable that the material of the gel member 30 has a property of having excellent affinity with the skin of a living body.

[0064] It is preferable to use an ultra-soft urethane resin that has a softness similar to that of human skin after hardening as the material for the gel member 30. There are no particular limitations on the hardening method for the gel member 30. A two-component mixed material may be used and hardened by pouring the material into a mold prepared in advance.

[0065] The gel member 30 is capable of propagating the ultrasonic waves generated from the piezoelectric element 10 toward the outside of the ultrasonic unit 1. For this reason, the gel member 30 can also be called an acoustically transparent gel. The gel member 30 has a contact surface 30F that contacts the ultrasonic wave generating surface 10F, and an exposed surface 30S that is the surface opposite to the contact surface 30F and is exposed to the outside of the ultrasonic unit 1.

[0066] The gel member 30 covers both the first FZP surface 20F and the second FZP surface 20S of the FZP member 20. The gel member 30 is provided on the ultrasound generating surface 10F so as to cover the FZP member 20. In other words, the FZP member 20 is embedded in the gel member 30. This makes the gel member 30 integrated with the FZP member 20. That is, the gel member 30 is disposed between the first FZP surface 20F and the ultrasound generating surface 10F, and is also disposed on the second FZP surface 20S. Furthermore, the gel member 30 is also disposed inside the slit 25. Because the hardened gel member 30 is not a fluid, the position of the FZP member 20 inside the gel member 30 is stably maintained.

[0067] The gel member 30 has adhesive properties. Therefore, the gel member 30 can also be referred to as an adhesive gel. Therefore, the contact surface 30F of the gel member 30 can be directly and easily attached to the ultrasound generating surface 10F. In other words, the gel member 30 adheres at least the FZP member 20 to the piezoelectric element 10. Furthermore, the gel member 30 can also be easily peeled off from the ultrasound generating surface 10F. In other words, the integrated product of the gel member 30 and the FZP member 20 is detachable from the piezoelectric element 10, and the integrated product alone can be disposed of without discarding the piezoelectric element 10.

[0068] In this embodiment, the ultrasound unit 1 is applied to an acupoint stimulation device. Therefore, the gel member 30 can be attached to the skin of a living body. In other words, the exposed surface 30S of the gel member 30 becomes the attachment surface that is attached to the skin of a living body. Therefore, the gel member 30 can also be called a gel pad.

[0069] In the gel member 30 having such a configuration, the intensity and focal length of the ultrasound can be adjusted by adjusting the thickness of the gel member 30. Furthermore, as will be described later, it is possible to focus ultrasound more efficiently than in the case of an acoustic lens having a concave portion. Specifically, in the Z direction, the gel member 30 has a first thickness T1 corresponding to the distance between the first FZP surface 20F and the contact surface 30F. Furthermore, the gel member 30 has a second thickness T2 corresponding to the distance between the second FZP surface 20S and the exposed surface 30S. By adjusting at least one of the first thickness T1 and the second thickness T2, the gel member 30 can adjust the focal length from the exposed surface 30S to the focal point or the focusing rate of the ultrasound.

[0070] <Selection from Multiple Gel Members> It is also possible to prepare multiple types of gel members with different thickness conditions, i.e., N types (N is an integer of 2 or greater), of gel members. Here, the thickness condition refers to the first thickness T1 and the second thickness T2. Specifically, multiple types of gel members are first designed according to the type of treatment target, the type of treatment region, the type of focal length, or the type of ultrasonic focusing rate. In designing the multiple types of gel members, at least one of the first thickness T1 and the second thickness T2 is freely selected, i.e., the thickness condition is freely selected. By conducting experiments or simulations on the gel members under the selected conditions, the thickness condition according to the type of treatment target, the type of treatment region, the type of focal length, or the type of ultrasonic focusing rate is determined. In other words, by conducting experiments or simulations while adjusting the thickness condition, the thickness condition according to the type of treatment target, the type of treatment region, the type of focal length, or the type of ultrasonic focusing rate can be determined.

[0071] The above-described preparation results in the production of multiple types of gel members with different thickness conditions. The phrase "different thickness conditions" means that the thickness conditions of each of the multiple types of gel members are different from one another. More specifically, for example, "different thickness conditions" for two gel members means that at least one of the first thickness T1 and the second thickness T2 of the two gel members is different. In other words, even if the first thickness T1 of two gel members is the same but the second thickness T2 is different from one another, the thickness conditions can be said to be different.

[0072] The method for selecting a gel member having appropriate thickness conditions from among a plurality of gel members is as follows: Here, the "gel member having appropriate thickness conditions" refers to a gel member to be used in actual treatment, and is selected by the user of the ultrasound unit 1 in consideration of the intended treatment target, intended treatment area, intended focal length, or intended ultrasound focusing rate.

[0073] The user determines the target treatment object, the target focal length, or the target ultrasonic focusing ratio. Next, the user selects a gel member having an appropriate thickness from among multiple types of gel members according to the target treatment object, the target focal length, or the target ultrasonic focusing ratio. The selected gel member is applied to the ultrasound unit 1. Therefore, by selecting an appropriate gel member from multiple gel members, it is possible to adjust the focal length or ultrasonic focusing ratio in the ultrasound unit 1. In other words, by adjusting at least one of the first thickness T1 and the second thickness T2, it is possible to adjust the focal length or ultrasonic focusing ratio.

[0074] <Effects> A user of the ultrasonic focusing device 200 brings the exposed surface 30S, which is exposed to the outside of the ultrasonic unit 1, into contact with the skin of a living body. In this state, the ultrasonic focusing device 200 is driven. Note that the exposed surface 30S may also be brought into contact with the skin of a living body while the ultrasonic focusing device 200 is driven.

[0075] The ultrasonic focusing device 200 includes an ultrasonic unit 1, an AC voltage generating unit 101, a signal generating unit 102, and a signal cable 103. Therefore, the ultrasonic focusing device 200 can supply a frequency signal to the ultrasonic unit 1. When the ultrasonic unit 1 receives the frequency signal, the voltage of the frequency signal is applied to the piezoelectric element 10, causing the piezoelectric element 10 to vibrate. This allows the piezoelectric element 10 to generate ultrasonic waves from the ultrasonic generating surface 10F.

[0076] The ultrasonic waves propagate through the gel member 30 located between the ultrasound generating surface 10F and the first FZP surface 20F, and reach the FZP member 20. The ultrasonic waves pass through the slits 25 and propagate to the gel member 30 located between the exposed surface 30S and the second FZP surface 20S. The ultrasonic waves reach the skin of the living body and then reach the treatment site located away from the skin surface of the living body. On the other hand, in areas of the FZP member 20 where the slits 25 are not provided, the ultrasonic waves do not reach the skin of the living body.

[0077] Ultrasonic waves that pass through the slits 25 of the FZP member 20 cause interference of the ultrasonic waves. Therefore, the FZP member 20 causes a diffraction phenomenon of the ultrasonic waves generated from the ultrasonic generating surface 10F, and focuses the ultrasonic waves at a focal point, which is the treatment site. In other words, the FZP member 20 can focus the energy of the ultrasonic waves at a focal point. This allows the FZP member 20 to stimulate the treatment site.

[0078] The ultrasonic unit 1 according to this embodiment provides the following excellent effects. When forming the FZP member 20, the slit 25 can be formed in the flat plate member without requiring high precision. This makes the process of forming the FZP member 20 extremely simple. In other words, when forming a conventional acoustic lens, it is necessary to process a spherical surface with a highly accurate curvature into a concave portion, which makes processing difficult and makes it difficult to reduce processing costs. In contrast, the ultrasonic unit 1 makes it easy to form the FZP member 20 that functions as an acoustic lens, thereby reducing the processing costs of the ultrasonic unit 1 including the FZP member 20.

[0079] Conventional ultrasonic therapy devices equipped with concave acoustic lenses require not only a gel member but also adhesive tape to attach the acoustic lens to the piezoelectric element. In contrast, the ultrasonic unit 1 can be obtained simply by attaching the adhesive gel member 30 to the ultrasound generating surface 10F. Therefore, compared to a structure in which an acoustic lens is attached to a piezoelectric element using adhesive tape, the number of components constituting the ultrasonic unit 1 can be reduced. This allows the ultrasonic unit 1 to be easily manufactured, thereby reducing the processing costs of the ultrasonic unit 1 equipped with the FZP member 20.

[0080] Furthermore, in a structure in which adhesive tape is disposed between the acoustic lens and the piezoelectric element, an interface is formed between the acoustic lens and the adhesive tape, and an interface is formed between the piezoelectric element and the adhesive tape. In other words, two interfaces are formed between the acoustic lens and the piezoelectric element. In this conventional configuration, ultrasonic waves are attenuated at the interfaces, making it impossible to reduce the amount of ultrasonic attenuation. In contrast, the ultrasonic unit 1 has a configuration in which an adhesive gel member 30 is attached to the ultrasonic generating surface 10F without using adhesive tape. Therefore, compared to conventional configurations, the number of interfaces is reduced, making it possible to suppress ultrasonic attenuation.

[0081] In an ultrasonic therapy device equipped with a conventional acoustic lens having a concave portion, a gel or resin material may be embedded in the concave portion. In this case, there is a risk of air remaining in the concave portion when the gel or resin material is embedded in the concave portion. If air remains in the concave portion, there is a problem of ultrasonic attenuation. In contrast, the ultrasonic unit 1 equipped with the FZP member 20 does not have a concave portion, and therefore, unlike conventional ultrasonic therapy devices, air is less likely to enter the ultrasonic unit 1. Therefore, the problem of ultrasonic attenuation due to air remaining in the concave portion can be solved.

[0082] In conventional ultrasonic treatment devices equipped with an acoustic lens, treatment is performed by applying a gel to the skin of a living body and then placing the acoustic lens against the skin. In contrast, the ultrasound unit 1 equipped with the gel member 30 can be used by contacting the skin with the exposed surface 30S of the gel member 30 without applying gel to the skin of a living body. Because the gel member 30 can be easily peeled off from the piezoelectric element 10, after treatment using the ultrasound unit 1 is completed, the used gel member 30 that has been in contact with the skin can be peeled off from the piezoelectric element 10 and discarded. The ultrasound unit 1 can be used by attaching a new gel member 30 to the piezoelectric element 10. Because the gel member 30 can be easily replaced, an ultrasound unit 1 with excellent hygiene can be realized.

[0083] Furthermore, in the case of this embodiment, there is no need to apply gel to the skin, so there is no need to wipe off the gel applied to the skin after using the ultrasound unit 1, and there is no need to remove the gel by rubbing the skin, so there is no discomfort to the person being treated.

[0084] The piezoelectric element 10 is a commercially available product that has been conventionally used. Therefore, there is no need to use a piezoelectric element with a special function or structure in the ultrasound unit 1. The ultrasound unit 1 can be realized simply by attaching an integrated product of the gel member 30 and the FZP member 20 to a conventional piezoelectric element. Therefore, in an ultrasound treatment device that uses a conventional acoustic lens, by using the gel member 30 and the FZP member 20 instead of the conventional acoustic lens, it is possible to obtain the same effects as the ultrasound unit 1.

[0085] <Other Embodiments> Next, other embodiments of the ultrasound unit will be described. In the embodiments described below, the same components as those in the first embodiment will be given the same reference numerals, and their description will be omitted or simplified. Configurations that differ from those described in the first embodiment will be mainly described. Regarding the omission of explanation, for example, a description of the drive of the ultrasound focusing device 200 used as an acupoint stimulation device will be omitted.

[0086] The FZP member 20 described in the following embodiments may be an FZP member without a connecting portion 23 as shown in FIG. 3A, or an FZP member with a connecting portion 23 as shown in FIG. 3B.

[0087] 4 is a schematic cross-sectional view partially illustrating the structure of an ultrasound unit 3 according to a second embodiment, as viewed from a direction parallel to the ultrasound unit 3. The second embodiment differs from the first embodiment in that an FZP member is in contact with the ultrasound generating surface of a piezoelectric element. Furthermore, the second embodiment does not use a gel member 30.

[0088] As shown in Figure 4, the ultrasonic unit 3 has a piezoelectric element 10 and an FZP member 20, similar to the first embodiment. The FZP member 20 is located on the ultrasonic wave generating surface 10F of the piezoelectric element 10. The FZP member 20 is located on the ultrasonic wave generating surface 10F. In other words, the ultrasonic wave generating surface 10F and the first FZP surface 20F are in contact with each other. No gel member is disposed between the ultrasonic wave generating surface 10F and the first FZP surface 20F. The FZP member 20 is a member different from the piezoelectric element 10.

[0089] The structure for fixing the FZP member 20 to the ultrasound generating surface 10F is not particularly limited. For example, an adhesive may be placed between the ultrasound generating surface 10F and the FZP member 20 to fix the FZP member 20 to the ultrasound generating surface 10F. The FZP member 20 can be peeled off from the ultrasound generating surface 10F.

[0090] In Figure 4, reference numeral 40 denotes a coating gel that is placed between the skin of a living body and the piezoelectric element 10 when using the ultrasound unit 3. The coating gel 40 may be applied to the skin of a living body first, or may be applied to the ultrasound generating surface 10F. In other words, the coating gel 40 is not a component of the ultrasound unit 3, but is a material that is used when using the ultrasound unit 3. In the following description, the coating gel 40 is applied to the skin of a living body.

[0091] <Effects> First, the application gel 40 is applied to the skin of a living body. The ultrasound unit 3 is placed on the skin via the application gel 40. As a result, the application gel 40 comes into contact with the ultrasound generating surface 10F, as shown in FIG. 4 . The application gel 40 covers the entire ultrasound generating surface 10F and the second FZP surface 20S so as to fill the slits 25 of the FZP member 20. In this state, the ultrasound focusing device 200 is driven.

[0092] Ultrasonic waves generated from the ultrasonic generating surface 10F of the piezoelectric element 10 pass through the slits 25 and propagate to the application gel 40. The ultrasonic waves reach the skin of the living body and then reach the treatment area located away from the skin surface of the living body. On the other hand, in areas of the FZP member 20 where the slits 25 are not provided, the ultrasonic waves do not reach the skin of the living body.

[0093] Ultrasonic waves that pass through the slits 25 of the FZP member 20 cause interference of the ultrasonic waves. Therefore, the FZP member 20 causes a diffraction phenomenon of the ultrasonic waves generated from the ultrasonic generating surface 10F, and focuses the ultrasonic waves at a focal point, which is the treatment site. In other words, the FZP member 20 can focus the energy of the ultrasonic waves at a focal point. This allows the FZP member 20 to stimulate the treatment site.

[0094] Unlike the first embodiment described above, the ultrasound unit 3 according to this embodiment does not use the FZP member 20, which reduces the number of members constituting the ultrasound unit 3. This makes it possible to easily manufacture the ultrasound unit 3.

[0095] 5 is a schematic cross-sectional view partially showing the structure of an ultrasonic unit 4 according to a third embodiment, as viewed from a direction parallel to the ultrasonic unit 4. The third embodiment differs from the first embodiment in that an FZP member is in contact with the ultrasonic wave generating surface of a piezoelectric element.

[0096] 5, the ultrasonic unit 4 has a piezoelectric element 10, an FZP member 20, and a gel member 30, similar to the first embodiment. The FZP member 20 is located on the ultrasonic generating surface 10F of the piezoelectric element 10. The FZP member 20 is located on the ultrasonic generating surface 10F. In other words, the ultrasonic generating surface 10F and the first FZP surface 20F are in contact with each other. The FZP member 20 is a member different from the piezoelectric element 10.

[0097] The gel member 30 covers the entire ultrasonic wave generating surface 10F and the second FZP surface 20S so as to fill the slits 25 of the FZP member 20. The gel member 30 is not disposed between the ultrasonic wave generating surface 10F and the first FZP surface 20F. In other words, the first thickness T1 of the gel member 30 is zero. The second thickness T2 of the gel member 30 can be changed as appropriate depending on the design of the gel member 30.

[0098] <Effects> First, the exposed surface 30S of the gel member 30 is brought into contact with the skin of a living body. In this state, the ultrasound focusing device 200 is driven. Ultrasonic waves generated from the ultrasound generating surface 10F of the piezoelectric element 10 pass through the slits 25 and propagate to the gel member 30. The ultrasonic waves reach the skin of the living body and then reach the treatment area located away from the skin surface of the living body. On the other hand, in areas of the FZP member 20 where the slits 25 are not provided, the ultrasonic waves do not reach the skin of the living body.

[0099] Ultrasonic waves that pass through the slits 25 of the FZP member 20 cause interference of the ultrasonic waves. Therefore, the FZP member 20 causes a diffraction phenomenon of the ultrasonic waves generated from the ultrasonic generating surface 10F, and focuses the ultrasonic waves at a focal point, which is the treatment site. In other words, the FZP member 20 can focus the energy of the ultrasonic waves at a focal point. This allows the FZP member 20 to stimulate the treatment site.

[0100] According to the ultrasound unit 4 of this embodiment, unlike the first embodiment described above, the gel member 30 is not disposed between the ultrasound generating surface 10F and the first FZP surface 20F, so the configuration of the gel member 30 can be simplified. In particular, there is no need to adjust the first thickness T1 of the gel member 30. The thickness of the gel member 30 can be adjusted by simply adjusting the second thickness T2. Therefore, the thickness of the gel member 30 can be easily controlled.

[0101] 6 is a schematic cross-sectional view partially showing the structure of an ultrasound unit 5 according to a fourth embodiment, as viewed from a direction parallel to the ultrasound unit 5. The fourth embodiment differs from the first embodiment in the structure of the gel member 30.

[0102] 6, the ultrasonic unit 5, like the first embodiment, has a piezoelectric element 10, an FZP member 20, and a gel member 30. The FZP member 20 is positioned away from the ultrasonic wave generating surface 10F.

[0103] The gel member 30 covers the ultrasound generating surface 10F and the first FZP surface 20F so as to fill the slits 25 of the FZP member 20. The second FZP surface 20S is not covered by the gel member 30. That is, in the Z direction, the position of the second FZP surface 20S and the position of the exposed surface 30S of the gel member 30 coincide with each other. In other words, the second thickness T2 of the gel member 30 is zero. The first thickness T1 of the gel member 30 can be changed as appropriate depending on the design of the gel member 30.

[0104] The application gel 40 shown in Figure 6 is the same as that in the second embodiment described above. The application gel 40 may be applied first to the skin of the living body, or may be applied to the exposed surface 30S. In other words, the application gel 40 is not a component of the ultrasound unit 5, but is a material used when using the ultrasound unit 5. In the following description, the application gel 40 is applied to the skin of the living body.

[0105] <Effects> First, the application gel 40 is applied to the skin of a living body. The ultrasound unit 5 is placed on the skin via the application gel 40. As a result, the application gel 40 covers the entire exposed surface 30S, as shown in Figure 5. In this state, the ultrasound focusing device 200 is driven.

[0106] Ultrasonic waves generated from the ultrasonic wave generating surface 10F of the piezoelectric element 10 propagate through the gel member 30 located between the ultrasonic wave generating surface 10F and the first FZP surface 20F, and reach the FZP member 20. The ultrasonic waves pass through the slits 25 provided in the FZP member 20 and propagate to the applied gel 40. The ultrasonic waves reach the skin of the living body and then reach the treatment area located away from the skin surface of the living body. On the other hand, in areas of the FZP member 20 where the slits 25 are not provided, the ultrasonic waves do not reach the skin of the living body.

[0107] Ultrasonic waves that pass through the slits 25 of the FZP member 20 cause interference of the ultrasonic waves. Therefore, the FZP member 20 causes a diffraction phenomenon of the ultrasonic waves generated from the ultrasonic generating surface 10F, and focuses the ultrasonic waves at a focal point, which is the treatment site. In other words, the FZP member 20 can focus the energy of the ultrasonic waves at a focal point. This allows the FZP member 20 to stimulate the treatment site.

[0108] According to the ultrasound unit 5 of this embodiment, unlike the first embodiment described above, the gel member 30 is not disposed on the second FZP surface 20S, and therefore the configuration of the gel member 30 can be simplified. In particular, there is no need to adjust the second thickness T2 of the gel member 30. The thickness of the gel member 30 can be adjusted by simply adjusting the first thickness T1. Therefore, the thickness of the gel member 30 can be easily controlled.

[0109] 7 is a schematic cross-sectional view partially showing the structure of an ultrasound unit 6 according to a fifth embodiment, as viewed from a direction parallel to the ultrasound unit 6. The fifth embodiment differs from the first embodiment in the structure of the gel member 30.

[0110] 7, the ultrasound unit 6 has a piezoelectric element 10, an FZP member 20, and a gel member 30, similar to the first embodiment. The gel member 30 has a first gel member 30A and a second gel member 30B. The first gel member 30A is an example of a first swelling body. The second gel member 30B is an example of a second swelling body.

[0111] The first gel member 30A is located between the ultrasound generating surface 10F and the second FZP surface 20S. The first gel member 30A adheres the FZP member 20 to the piezoelectric element 10. The second gel member 30B is detachable from the second FZP surface 20S. In other words, the second gel member 30B is detachable from the first gel member 30A. The first gel member 30A has a first thickness T1. The second gel member 30B has a second thickness T2.

[0112] The first gel member 30A and the second gel member 30B are made of the same material. In other words, it is preferable that the refractive index of the first gel member 30A and the refractive index of the second gel member 30B are equal to each other. However, the first gel member 30A and the second gel member 30B may be made of different materials as long as the degree of obstruction to ultrasonic wave propagation can be sufficiently reduced.

[0113] The dotted line connecting the two points indicated by the symbols A and B in Fig. 7 is the surface between the first gel member 30A and the second gel member 30B. Fig. 7 shows that an interface exists between the first gel member 30A and the second gel member 30B. This surface is the surface (peeling surface) where the second gel member 30B is peeled from the first gel member 30A. At this surface, the first gel member 30A and the second gel member 30B are in close contact with each other, and it is preferable that no interface that would obstruct the propagation of ultrasound is formed.

[0114] <Effects> With the ultrasound unit 6 according to this embodiment, after treatment using the ultrasound unit 6 is completed, the used second gel member 30B that has been in contact with the skin can be peeled off from the piezoelectric element 10 and discarded, while leaving the first gel member 30A disposed between the piezoelectric element 10 and the FZP member 20. The ultrasound unit 6 can be used again by attaching a new second gel member 30B to the first gel member 30A. Because the second gel member 30B can be easily replaced, an ultrasound unit 6 that is highly hygienic can be realized.

[0115] 8A is a schematic cross-sectional view partially illustrating the structure of a diffractive gel tape according to a sixth embodiment, as viewed from a direction parallel to the diffractive gel tape. The diffractive gel tape 50 according to this embodiment can be used as the FZP member 20 and the gel member 30 constituting each of the ultrasound units 4 to 6 shown in FIGS. 5 to 7. The diffractive gel tape 50 is an example of a diffractive swelling tape.

[0116] As shown in FIG. 8 , the diffractive gel tape 50 has an FZP member 20 and a gel member 30. The gel member 30 covers at least one of the first FZP surface 20F and the second FZP surface 20S of the FZP member 20. In this embodiment, the gel member 30 covers the first FZP surface 20F and exposes the second FZP surface 20S. Note that the gel member 30 may also cover the second FZP surface 20S. In this case, the gel member 30 exposes the second FZP surface 20S.

[0117] The diffractive gel tape 50 may be a tape extending in the Y direction. In this case, the diffractive gel tape 50 has a plurality of FZP members 20 arranged in the Y direction.

[0118] The diffractive gel tape 50 may have multiple notches formed therein to separate the multiple FZP members 20 one by one. In this case, the multiple notches are aligned in the Y direction. By having multiple notches pre-formed in the diffractive gel tape 50 extending in the Y direction, a user of the diffractive gel tape 50 can easily separate the multiple FZP members 20 one by one. Note that the following description will be given of a cross section of a portion of the diffractive gel tape extending in the Y direction. The same applies to the descriptions in Figures 9 to 11 described below.

[0119] The diffractive gel tape 50 is adhesive because it is mainly composed of the gel member 30. For this reason, the diffractive gel tape 50 can also be called an adhesive tape. Furthermore, because the diffractive gel tape 50 is a member in which the gel member 30 and the FZP member 20 are integrated, it can also be called an integrated tape. Such a diffractive gel tape 50 can be directly and easily attached to the contact surface 30F of the piezoelectric element 10.

[0120] The diffractive gel tape 50 has a first tape surface 50F and a second tape surface 50S opposite the first tape surface 50F. In this embodiment, the first tape surface 50F is a surface that corresponds to the contact surface 30F of the gel member 30. The second tape surface 50S is a surface that corresponds to the exposed surface 30S of the gel member 30. Note that the first tape surface 50F may correspond to the exposed surface 30S. In this case, the second tape surface 50S corresponds to the contact surface 30F.

[0121] The distance between the first tape surface 50F and the first FZP surface 20F is a third thickness T3. The third thickness T3 corresponds to the first thickness T1 or the second thickness T2 described above. By adjusting the third thickness T3, the diffractive gel tape 50 can adjust the focal length or the focusing rate of the ultrasonic waves obtained by the ultrasonic unit.

[0122] In other words, the position of the surface of the diffractive gel tape 50 that is attached to the piezoelectric element 10 is not limited. Depending on the configuration of the ultrasound unit shown in Figures 5 to 7, the first tape surface 50F of the diffractive gel tape 50 may be attached to the piezoelectric element 10, or the second tape surface 50S of the diffractive gel tape 50 may be attached to the piezoelectric element 10. When the diffractive gel tape 50 is applied to the ultrasound unit 6 shown in Figure 7, the second tape surface 50S becomes the surface that comes into contact with the applied gel 40.

[0123] In this embodiment, the diffractive gel tape 50 has a first protective sheet 51F and a second protective sheet 51S. The first protective sheet 51F covers the first tape surface 50F. The second protective sheet 51S covers the second tape surface 50S. The first protective sheet 51F and the second protective sheet 51S each have the function of protecting the FZP member 20 and the gel member 30, respectively. Furthermore, the first protective sheet 51F and the second protective sheet 51S each function as a support substrate that supports the FZP member 20, the gel member 30, and the diffractive gel tape 50.

[0124] <Effects> The diffractive gel tape 50 according to this embodiment can provide the same effects as the ultrasound units 4 to 6. Furthermore, after treatment using the diffractive gel tape 50 is completed, the used diffractive gel tape 50 that has been in contact with the skin can be peeled off from the piezoelectric element 10 and discarded. By attaching a new diffractive gel tape 50 to the piezoelectric element 10, the ultrasound unit can be used repeatedly. Because the diffractive gel tape 50 can be easily replaced, an ultrasound unit with excellent hygiene can be achieved.

[0125] By covering both sides of the diffractive gel tape 50 with the first protective sheet 51F and the second protective sheet 51S, it is possible to prevent dust and dirt from adhering to the gel member 30 before use of the ultrasound unit.

[0126] Furthermore, the first protective sheet 51F and the second protective sheet 51S protect the FZP member 20 and the gel member 30, thereby preventing damage to the FZP member 20 and the gel member 30. In the example shown in Fig. 8A, the first protective sheet 51F and the second protective sheet 51S are attached to both sides of the diffractive gel tape 50, but a configuration in which a protective sheet is attached to only one side of the diffractive gel tape 50 may also be employed.

[0127] <Modification of Diffractive Gel Tape 50> FIG. 8B is a plan view partially illustrating a modification of the diffractive gel tape according to the sixth embodiment. In the diffractive gel tape 50, multiple diffractive gel members 55 are arranged on a first protective sheet 51F. Each of the multiple diffractive gel members 55 includes the FZP member 20 and gel member 30 shown in FIG. 3B. The multiple diffractive gel members 55 are aligned along the extension direction of the first protective sheet 51F, i.e., the Y direction. Each of the multiple diffractive gel members 55 is individually separated and arranged on the first protective sheet 51F in advance. The cross-sectional structure of the diffractive gel member 55 may be, for example, the structure shown in FIG. 8A. The multiple diffractive gel members 55 may be connected by a connecting portion 56 made of the same material as the gel member 30.

[0128] When using the ultrasound unit, the user first peels the diffractive gel member 55 from the first protective sheet 51F. Then, the user attaches one side of the diffractive gel member 55 to the skin of a living body. Furthermore, the user attaches the piezoelectric element 10 to the other side of the diffractive gel member 55. For example, a signal cable 103 is connected to the piezoelectric element 10 in advance. This allows the ultrasound unit to be realized. Note that instead of the first protective sheet 51F, multiple diffractive gel members 55 may be arranged on the second protective sheet 51S. Also, after attaching the piezoelectric element 10 to one side of the diffractive gel member 55, the other side of the diffractive gel member 55 may be attached to the skin of a living body.

[0129] <Seventh embodiment> Figure 9 is a schematic cross-sectional view partially showing the structure of a diffractive gel tape according to a seventh embodiment, as viewed from a direction parallel to the diffractive gel tape. In the seventh embodiment, the same components as those in the sixth embodiment are given the same reference numerals, and their description will be omitted or simplified. The diffractive gel tape 60 according to this embodiment can be used as the FZP member 20 and gel member 30 constituting the ultrasound unit 1A shown in Figures 2 and 3B. The diffractive gel tape 60 is an example of a diffractive swelling tape.

[0130] 9, the diffractive gel tape 60 has the FZP member 20 and gel member 30 described in the first embodiment. The diffractive gel tape 60 differs from the diffractive gel tape 50 described above in that the gel member 30 covers both the first FZP surface 20F and the second FZP surface 20S of the FZP member 20. Descriptions of the same configuration as the diffractive gel tape 50 will be omitted.

[0131] The diffractive gel tape 60 has a first tape surface 60F and a second tape surface 60S opposite the first tape surface 60F. In this embodiment, the first tape surface 60F corresponds to the contact surface 30F of the gel member 30. In other words, the first tape surface 60F is the surface that contacts the ultrasound generating surface 10F. The second tape surface 60S corresponds to the exposed surface 30S of the gel member 30. A first protective sheet 51F covers the first tape surface 60F. A second protective sheet 51S covers the second tape surface 60S.

[0132] The distance between the first tape surface 60F and the first FZP surface 20F is a first thickness T1. The distance between the second tape surface 60S and the second FZP surface 20S is a second thickness T2. By adjusting either the first thickness T1 or the second thickness T2, the diffractive gel tape 60 can adjust the focal length or the focusing rate of the ultrasonic waves obtained by the ultrasonic unit 1.

[0133] <Modification of Diffractive Gel Tape 60> The diffractive gel tape 60 may be applied to the modification shown in FIG. 8B described above.

[0134] <Method of manufacturing diffractive gel tape 60> Figures 10A and 10B are schematic cross-sectional views partially showing the structure of the diffractive gel tape 60 according to the seventh embodiment described above, and are figures for explaining the method of manufacturing the diffractive gel tape 60.

[0135] First, as shown in Fig. 10A, a base 70 and a frame 71 are prepared. The base 70 has a base surface 70F. The frame 71 has a frame inner surface 71N. The area surrounded by the base surface 70F and the frame inner surface 71N is a mold 72 for molding the diffractive gel tape 60.

[0136] The base 70 and the frame 71 are made of a material that has excellent releasability and liquid repellency with respect to the urethane resin that constitutes the gel member 30. Such materials include resin materials and metal materials. Note that the base surface 70F and the frame inner surface 71N may also have releasability and liquid repellency with respect to the constituent material of the gel member 30.

[0137] With the frame 71 placed on the base surface 70F of the base 70, the FZP member 20 is placed inside the mold 72. The height from the base surface 70F to the second FZP surface 20S of the FZP member 20 corresponds to the second thickness T2 described above. This height is set by a jig or the like that is used repeatedly only in the manufacturing method of the diffractive gel tape. A spacer made of the material that constitutes the FZP member 20 may be placed between the base surface 70F and the FZP member 20.

[0138] In this case, the spacers may be arranged so as to be aligned in the Y direction in which the diffractive gel tape 60 extends. For example, the spacers may be formed near the positions of the multiple notches formed in the diffractive gel tape 50. The spacers may be separable from the FZP members 20. For example, the spacers may have a shape or arrangement that allows them to be separated from the FZP members 20 when the multiple FZP members 20 formed in the diffractive gel tape 60 can be easily separated one by one.

[0139] Next, as shown in FIG. 10B , urethane resin, which is the material for the gel member 30, is poured into the mold 72. As a result, the urethane resin material covers the entire FZP member 20 and fills the inside of the slits 25. The distance between the liquid surface, which becomes the contact surface 30F of the gel member 30, and the first FZP surface 20F corresponds to the first thickness T1 described above. The urethane resin material is then cured. The method for curing the urethane resin material is not particularly limited. A curing method appropriate for the type of urethane resin material is used. The base 70 and frame 71 are then removed from the cured urethane resin member. A first protective sheet 51F is then attached to the first tape surface 60F. Furthermore, a second protective sheet 51S is attached to the second tape surface 60S. This results in the diffractive gel tape 60 shown in FIG. 9 .

[0140] <Effects> The diffractive gel tape 60 according to this embodiment can provide the same effects as the ultrasound unit 1. Furthermore, after treatment using the diffractive gel tape 60 is completed, the used diffractive gel tape 60 that has been in contact with the skin can be peeled off from the piezoelectric element 10 and discarded. By attaching a new diffractive gel tape 60 to the piezoelectric element 10, the ultrasound unit 1 can be used repeatedly. Because the diffractive gel tape 60 can be easily replaced, an ultrasound unit 1 with excellent hygiene can be achieved.

[0141] In the above-described manufacturing method of the diffractive gel tape 60, a chamber capable of adjusting the internal pressure may be used to prevent air bubbles from being mixed into the diffractive gel tape 60. In this case, by manufacturing the diffractive gel tape 60 in a reduced pressure atmosphere in the chamber, it is possible to manufacture a diffractive gel tape 60 in which the mixing of air bubbles is suppressed. This makes it possible to suppress the attenuation of ultrasonic waves caused by the mixing of air bubbles.

[0142] 11A to 11C, a modified method of manufacturing the diffractive gel tape 60 will be described. In this modified example, the same components as those in FIGS. 10A and 10B are denoted by the same reference numerals, and their description will be omitted or simplified.

[0143] 11A , with frame 71 placed on base surface 70F of base 70, first urethane resin 31, which will be the material for gel member 30, is poured into mold 72. The position of upper surface 31A of first urethane resin 31 in the Z direction is set so that second thickness T2 of gel member 30 is obtained. In other words, the distance between upper surface 31A and base surface 70F corresponds to second thickness T2. Then, first urethane resin 31 is cured.

[0144] Next, the FZP member 20 is placed on the upper surface 31A of the first urethane resin 31. This determines the height of the FZP member 20 from the base surface 70F in the Z direction. In this modification, it is possible to omit spacers for setting the height of the FZP member 20. The method for placing the FZP member 20 on the upper surface 31A is not limited.

[0145] Next, as shown in FIG. 11C , the second urethane resin 32, which is the material for the gel member 30, is poured into the mold 72. As a result, the second urethane resin 32 covers the entire FZP member 20 and fills the inside of the slit 25. The distance between the liquid surface 32A of the second urethane resin 32, which forms the contact surface 30F of the gel member 30, and the first FZP surface 20F corresponds to the first thickness T1 described above. The second urethane resin 32 is then cured. The base 70 and frame 71 are then removed from the cured first urethane resin 31 and second urethane resin 32. This results in the diffractive gel tape 60 shown in FIG. 9 . According to this modification, the position of the FZP member 20 in the Z direction can be easily set.

[0146] <Modification of Ultrasound Unit> In the above-described embodiment, a structure has been described in which the ultrasound focusing device 200 drives one ultrasound unit. The ultrasound unit of the above-described embodiment may be applied to an ultrasound unit array in which a plurality of ultrasound units are arranged.

[0147] An example of the ultrasound unit array is a one-dimensional ultrasound unit array in which a plurality of ultrasound units are arranged in one dimension. Specifically, a configuration in which a plurality of ultrasound units are arranged in the X direction or the Y direction can be adopted.

[0148] An example of an ultrasound unit array is a two-dimensional ultrasound unit array in which multiple ultrasound units are arranged two-dimensionally. Specifically, a configuration in which multiple ultrasound units are arranged in both the X and Y directions can be adopted. For example, a planar array can be realized in a structure in which a two-dimensional ultrasound unit array is attached to a planar sheet. Furthermore, a curved array can be realized in a structure in which a two-dimensional ultrasound unit array is attached to a deformable or stretchable sheet. As described above, in a configuration in which a diffractive gel tape is attached to a piezoelectric element, multiple ultrasound units can be easily applied to a two-dimensional ultrasound unit array.

[0149] <Application Examples of Ultrasound Unit, Diffractive Gel Tape, and Ultrasound Focusing Device> In the above-described embodiment, the application of an ultrasound unit, a diffractive gel tape, and an ultrasound focusing device to an acupuncture point stimulation device has been described. The present invention is not limited to acupuncture point stimulation devices that stimulate treatment sites, and may also be used for treatment, diagnosis, surgery, etc. on living organisms. For example, by using a measurement unit that combines the above-described ultrasound unit with a reflected wave sensor that detects reflected ultrasound waves, it is possible to realize various medical diagnostic devices and measurement devices. Below are listed examples of applications of the present invention.

[0150] (1) Ultrasonic Sensor The ultrasonic sensor includes an ultrasonic unit and a measurement unit having a reflected wave sensor. The ultrasonic unit may be configured to have not only the above-mentioned function of focusing ultrasonic waves but also the function of a reflected wave sensor. The ultrasonic sensor can be used as a sensor whose measurement position within the body can be changed. For example, the sensor is attached to the body surface directly above the blood vessels of a living body, and various information regarding the behavior of the blood vessels and the movement of blood can be obtained.

[0151] (2) Sheet-shaped ultrasonic probe The sheet-shaped ultrasonic probe includes multiple measurement units each having an ultrasonic unit and a reflected wave sensor. For example, the sheet-shaped ultrasonic probe may be a sheet on which multiple ultrasonic units configured to have not only the above-mentioned function of focusing ultrasonic waves but also the function of a reflected wave sensor are arranged. The multiple ultrasonic units may be arranged in a one-dimensional array in a single row or in a two-dimensional array in the X and Y directions. Such an ultrasonic probe is attached to the body surface of a living body. The sheet-shaped ultrasonic probe may be deformable according to the shape of the body surface. The sheet-shaped ultrasonic probe may be flexible enough to be bent in a predetermined direction for ultrasonic beamforming, ultrasonic collimation, and ultrasonic modulation. For example, by attaching such an ultrasonic probe to the neck, it can measure the carotid artery and jugular vein of a living body. Furthermore, by attaching the ultrasonic probe to the body surface above the clavicle, various information regarding blood in the inferior vena cava and inferior aorta can be obtained.

[0152] Furthermore, such an ultrasound probe can be passed between the ribs and placed inside the living body to measure the shape and movement of the heart. The ultrasound probe can obtain various information about the heart. Furthermore, image processing such as cardiac imaging can be performed based on the information obtained by the ultrasound probe. Furthermore, by attaching the ultrasound probe to the surface of the neck, it is possible to measure the movement of the throat and evaluate the muscles that move the epiglottis.

[0153] Next, the effects of the present invention will be specifically explained with reference to examples. Below, we will explain the case where an ultrasound unit is applied to an acupuncture point stimulation device. In this case, we will explain the difference between an ultrasound unit equipped with a conventional acoustic lens having a concave portion and the ultrasound unit of the present invention.

[0154] (Example 1) Fig. 12A is a cross-sectional view schematically showing an ultrasound unit according to Examples 1 and 2, and is a view for explaining the conditions of the simulation. Fig. 12B is a cross-sectional view schematically showing an ultrasound unit according to Example 1, and is a view for explaining an analytical model of the simulation. Fig. 12C is a view showing the results of a simulation of the ultrasound unit according to Example 1, and is a graph showing the relationship between the design focal length (mm) and the focal length FL (mm) from the skin surface SF. Fig. 12D is a view showing the results of a simulation of the ultrasound unit according to Example 1, and is a graph showing the relationship between the design focal length (mm) and the ultrasound intensity (kW / m ２ 12E is a graph showing the relationship between the focal distance FL (mm) from the skin surface SF and the ultrasonic intensity (kW / m ２ ) is a graph showing the relationship between

[0155] In the simulation of Example 1, the ultrasound unit 1 shown in Figure 3A is used. The symbol W represents water, which is used as an example of skin in the simulation. The symbol WB represents an open interface. The symbol SF corresponds to the exposed surface 30S of the gel member 30 constituting the ultrasound unit 1 and represents the skin surface. At the skin surface SF, the exposed surface 30S is in contact with the water W. The symbol FL represents the focal length. In other words, the focal length FL means the distance from the skin surface SF toward the interior of the skin. The symbol UW represents ultrasound waves generated from the ultrasound generating surface 10F.

[0156] In the simulation of Example 1, the frequency of the ultrasonic waves generated from the piezoelectric element 10 was set to 3 MHz. The sound pressure was 2.8×10 ４ The sound pressure was measured in Pa. Here, sound pressure refers to the pressure generated on the ultrasonic wave generating surface of the piezoelectric element 10. The FZP member 20 was formed using acrylic resin. The gel member 30 was formed using Human Skin Gel Solution (registered trademark). The density of the gel member 30 was approximately 998.6 kg / m ３ and the propagation velocity of the ultrasonic wave in the gel member 30 is 1141.5 m / s.

[0157] 12C, 12D, and 12E, simulations were performed using 13 samples in which the diameter of the piezoelectric element 10 was 5 mm and 13 samples in which the diameter of the piezoelectric element 10 was 6 mm. This allowed the intensity of ultrasound propagating from the surface of the skin, which is the body surface, toward the interior of the skin to be analyzed.

[0158] The design focal length was adjusted so that the focal length FL was approximately 3 mm and so that the strongest ultrasonic wave intensity was obtained. Here, the thickness of the FZP member 20, the width of the slit 25, and the thickness of the gel member 30 were adjusted to adjust the design focal length. Since the ultrasonic frequency was 3 MHz, the thickness of the FZP member 20 was set to 0.4 mm. The width of the slit 25 was adjusted within a range of 0.4 mm to 1.0 mm. The thickness of the gel member 30 was adjusted within a range of 0.4 mm to 2.4 mm.

[0159] In Figures 12D and 12E, the ultrasonic intensity was 30 kW / m ２ The position where the ultrasound intensity is 30kW / m is shown by a thick line. This intensity means the ultrasound intensity that was actually recognized as effective when acupuncture point stimulation was performed using a focused ultrasound with an ultrasound unit. Specifically, at the focal point, the ultrasound intensity was 30kW / m. ２ In addition, the 30 kW / m indicated by the thick line in the drawings for explaining the comparative example, example 2, and example 3 described later. ２ The meaning of the ultrasonic intensity is the same as in FIGS. 12D and 12E.

[0160] (Evaluation Results) The results shown in Figures 12C, 12D, and 12E reveal the following: (A1) It was revealed that the focal distance FL from the skin surface SF can be adjusted by adjusting the design focal distance. (A2) In Example 1, the design focal distance was adjusted so that the focal distance FL was about 3 mm and the strongest ultrasound intensity was obtained, but it was revealed that the focal distance FL can be set to 3 mm or more by adjusting the design focal distance. (A3) By adjusting the design focal distance, that is, when the focal distance FL is about 3 mm, it was possible to achieve a power of 30 kW / m, at which the effect of acupoint stimulation was observed. ２ It was found that ultrasonic intensity exceeding

[0161] (Comparative Example) Fig. 13A is a cross-sectional view schematically showing an ultrasonic unit of a comparative example, and is a view for explaining the conditions of the simulation. Fig. 13B is a cross-sectional view schematically showing an ultrasonic unit of a comparative example, and is a view for explaining an analytical model of the simulation. Fig. 13C is a view showing the results of a simulation of the ultrasonic unit of the comparative example, and is a graph showing the relationship between the focal length FL (mm) and the radius of curvature (mm) of the acoustic lens. Fig. 13D is a view showing the results of a simulation of the ultrasonic unit of the comparative example, and is a graph showing the relationship between the focal length FL (mm) and the ultrasonic intensity (kW / m ２ ) is a graph showing the relationship between

[0162] The simulation of the comparative example uses an ultrasound unit 501 equipped with an acoustic lens having a concave surface. The ultrasound unit 501 includes a piezoelectric element 510 having an ultrasound generating surface 510F, an acoustic lens 520 having a concave surface 521, a gel member 530 provided on the surface of the concave surface 521, and adhesive tape 540 that adheres the acoustic lens 520 to the ultrasound generating surface 510F. The gel member 530 has an exposed surface 530S that contacts water W, which is used as an example of skin in the simulation. The exposed surface 530S coincides with the skin surface SF.

[0163] The piezoelectric element 510 has the same configuration as the piezoelectric element 10 that constitutes the ultrasound unit 1. The focal length FL is the distance from the skin surface SF toward the inside of the skin. The ultrasound UW is generated from the ultrasound generating surface 510F. The distance between the edge 520E of the acoustic lens 520 and the skin surface SF is set to 1 mm. The acoustic lens 520 has a radius of curvature R (mm). In the comparative example, the radius of curvature R was adjusted within a range of 3 to 19 mm.

[0164] In the simulation of the comparative example, the frequency of the ultrasonic waves generated from the piezoelectric element 510 was set to 2 MHz or 3 MHz. The sound pressure was 1.0×10 ５ The acoustic pressure was set to Pa. Here, the sound pressure refers to the pressure generated on the ultrasonic wave generating surface of the piezoelectric element 510. The acoustic lens 520 was formed using acrylic resin. The material of the gel member 530 was the same as that of the gel member 30.

[0165] 13C and 13D, a total of 26 samples were prepared and simulations were performed. This allowed for the analysis of the intensity of ultrasound propagating from the surface of the skin, which is the body surface, to the interior of the skin. Specifically, four samples were prepared in which the ultrasound frequency was set to 2 MHz and the piezoelectric element 10 had a diameter of 5 mm ("○ 2 MHz 5 mm"). Eight samples were prepared in which the ultrasound frequency was set to 3 MHz and the piezoelectric element 10 had a diameter of 5 mm ("□ 3 MHz 5 mm"). Six samples were prepared in which the ultrasound frequency was set to 2 MHz and the piezoelectric element 10 had a diameter of 6 mm ("◇ 2 MHz 6 mm"). Eight samples were prepared in which the ultrasound frequency was set to 3 MHz and the piezoelectric element 10 had a diameter of 6 mm ("△ 3 MHz 6 mm").

[0166] (Evaluation Results) The results shown in Figures 13C and 13D reveal the following: (B1) In the comparative example, the focal length FL is adjusted by adjusting the radius of curvature R of the acoustic lens 520. It was revealed that the focal length FL is reduced by reducing the radius of curvature R, and that the focal length FL is increased by increasing the radius of curvature R. (B2) It was revealed that the ultrasonic intensity is reduced by increasing the focal length FL. (B3) It was revealed that the ultrasonic intensity is reduced when the frequency is low. (B4) The ultrasonic intensity is increased by reducing the focal length FL, but the ultrasonic intensity is reduced below 30 kW / m ２ It was found that ultrasound intensity exceeding this level could not be obtained, meaning that the effect of acupoint stimulation could not be obtained.

[0167] Example 2 As shown in FIG. 12A , the gel member 30 constituting the ultrasound unit 1 according to Example 2 has a first gel region 35 having a first thickness T1 and a second gel region 36 having a second thickness T2. The first gel region 35 is located between the first FZP surface 20F and the ultrasound generating surface 10F. The second gel region 36 is located between the second FZP surface 20S and the skin surface SF (exposed surface 30S). In Example 2, the focal length or ultrasound intensity was analyzed for each of the first thickness T1 and the second thickness T2. The simulation conditions for Example 2 were the same as those for Example 1 described above. Simulations were performed for a piezoelectric element 10 with a diameter of 5 mm and a piezoelectric element 10 with a diameter of 6 mm.

[0168] 14A is a graph showing the results of a simulation of the ultrasonic unit according to Example 2, illustrating the relationship between the focal length FL (mm) and the second thickness T2 (mm) of the second gel region 36. FIG. 14B is a graph showing the results of a simulation of the ultrasonic unit according to Example 2, illustrating the relationship between the focal length FL (mm) and the first thickness T1 (mm) of the first gel region 35. FIG. 14C is a graph showing the results of a simulation of the ultrasonic unit according to Example 2, illustrating the relationship between the second thickness T2 (mm) of the second gel region 36 and the ultrasonic intensity (kW / m ２ 14D is a graph showing the relationship between the first thickness T1 (mm) of the first gel region 35 and the ultrasonic intensity (kW / m ２ ) is a graph showing the relationship between

[0169] In each of Figures 14A, 14B, 14C, and 14D, the symbol "D5mm" indicates that the diameter of the piezoelectric element 10 is 5 mm. The symbol "D6mm" indicates that the diameter of the piezoelectric element 10 is 6 mm. The symbol "t0.0mm" indicates that the thickness of the gel region is 0.0 mm. The symbol "t0.4mm" indicates that the thickness of the gel region is 0.4 mm. The symbol "t0.8mm" indicates that the thickness of the gel region is 0.8 mm. The symbol "t1.2mm" indicates that the thickness of the gel region is 1.2 mm.

[0170] (Evaluation Results) The results shown in Figures 14A, 14B, 14C, and 14D revealed the following: (C1) It was revealed that the focal length FL can be adjusted by adjusting the second thickness T2. In particular, it was revealed that the focal length FL can be reduced by increasing the second thickness T2. (C2) Although the focal length FL changes when the first thickness T1 is adjusted, it was revealed that adjusting the first thickness T1 does not significantly affect the focal length FL. (C3) It was revealed that the focal length FL can be adjusted not only by simply adjusting the thickness of the gel member 30 including the FZP member 20, but also by adjusting the thicknesses of the first gel region 35 and the second gel region 36. (C4) It was revealed that the ultrasonic intensity can be adjusted by adjusting the second thickness T2. In other words, it was revealed that the focusing rate of the ultrasonic waves can be adjusted. In particular, it was revealed that the ultrasonic intensity can be increased by increasing the second thickness T2. (C5) It was revealed that the ultrasonic intensity can be adjusted by adjusting the first thickness T1. In other words, it was found that the focusing rate of the ultrasonic waves can be adjusted. In particular, it was found that the ultrasonic intensity can be increased by increasing the first thickness T1. (C6) 30 kW / m ２ It has become clear that adjusting the thickness of the first gel region 35 and the second gel region 36 is effective in obtaining an ultrasonic wave intensity exceeding .

[0171] Example 3 Figure 15 is a diagram showing the results of comparing Example 1 and the comparative example with respect to the maximum ultrasonic intensity under conditions 1 to 4. Under condition 1, the diameter of the piezoelectric element 10 is 5 mm, and the focal length FL is 3 mm. Under condition 2, the diameter of the piezoelectric element 10 is 5 mm, and the focal length FL is 5 mm. Under condition 3, the diameter of the piezoelectric element 10 is 6 mm, and the focal length FL is 3 mm. Under condition 4, the diameter of the piezoelectric element 10 is 6 mm, and the focal length FL is 5 mm.

[0172] (Evaluation Results) The results shown in Figure 15 reveal the following: (D1) Under each of conditions 1 to 4, Example 1 was found to have a higher maximum ultrasonic intensity than the comparative example. In particular, under conditions 1, 3, and 4, Example 1 achieved a maximum ultrasonic intensity of 30 kW / m, at which the effect of acupoint stimulation was observed. ２ It was clear that a high ultrasonic intensity of 30 kW / m or more could be obtained. ２ It was found that ultrasonic intensity exceeding this value could not be obtained.

[0173] Example 4 Example 4 will be described with reference to Figures 16 to 30. Figure 17 is a diagram showing the configuration of a test device used in Example 4. Figures 18 to 30 show simulation results and experimental results using test device 80. In the following description, the experimental results using test device 80 may be simply referred to as "experimental results."

[0174] Based on the simulation results obtained from Examples 1 to 3 described above, Example 4 further verified the effects of the present invention. Here, simulations were performed for Examples involving four lenses and a Comparative Example that did not use a lens (FZP member). Furthermore, the FZP member and gel member that make up the ultrasound unit were actually manufactured. Each of the four manufactured lenses is an integral unit of the FZP member and gel member described in the above embodiment. In the following description, the four lenses will be referred to as Lenses 1 to 4.

[0175] FIG. 16 is a table showing the conditions of lenses 1 to 4 (lenses 1 to 4). "PZT diameter" refers to the diameter of the piezoelectric element 10. R1 to R4 listed under "FZP lens size" correspond to R1 to R4 of the FZP member 20 shown in FIG. 3B. Symbol R1 is the distance in the radial direction from the center O of the ultrasonic unit 1A to the inner edge of the inner FZP section 21, i.e., the inner diameter of the inner FZP section 21. Symbol R2 is the distance in the radial direction from the center O of the ultrasonic unit 1A to the outer edge of the inner FZP section 21, i.e., the outer diameter of the inner FZP section 21. Symbol R3 is the distance in the radial direction from the center O of the ultrasonic unit 1A to the inner edge of the outer FZP section 22, i.e., the inner diameter of the outer FZP section 22. The symbol R4 is the distance in the radial direction from the center O of the ultrasonic unit 1A to the outer edge of the outer FZP section 22, i.e., the outer diameter of the outer FZP section 22. In other words, the symbol R4 is the distance in the radial direction from the center O of the ultrasonic unit 1A to the outer peripheral edge of the FZP member 20, i.e., the diameter of the FZP member 20.

[0176] "Gel thickness" refers to the thickness of the gel member 30 shown in FIG. 12A. "t1" corresponds to the first thickness T1 and is the thickness of the first gel region 35. "t2" corresponds to the second thickness T2 and is the thickness of the second gel region 36. Lenses 1 to 4 differ from one another in terms of "PZT diameter," "FZP lens size," and "Gel thickness." Lenses 1 to 4 used in the experiment using test device 80 differ from the simulation in that they use a connecting portion 23. Specifically, in lenses 1 to 4 used in the experiment using test device 80, the inner FZP portion 21 and the outer FZP portion 22 are connected by the connecting portion 23 as shown in FIG. 3B. In contrast, lenses 1 to 4 used in the simulation each have a structure in which the inner FZP portion 21 and the outer FZP portion 22 are not connected by the connecting portion 23.

[0177] <Simulation Results> Figures 18, 20, 22, 24, 26, and 28 each show the results of the following simulations. - Figure 18: Simulation results of a comparative example using only a piezoelectric element with a diameter of 6 mm without using a lens (FZP member) - Figure 20: Simulation results of lens 1 - Figure 22: Simulation results of lens 2 - Figure 24: Simulation results of a comparative example using only a piezoelectric element with a diameter of 5 mm without using a lens (FZP member) - Figure 26: Simulation results of lens 3 - Figure 28: Simulation results of lens 4

[0178] In each of the above figures, the horizontal axis indicates the position (mm) on the surface of the body. The vertical axis indicates the depth (mm) from the body surface. Here, the "body surface" corresponds to the surface of the skin of a living body. In the simulation, the physical properties of water, which are similar to those of skin, are used. In the simulation results, the range of 0 to 1.8 kW / m ２ In each of the simulation results, the symbol S0 indicates that the ultrasonic intensity is in the range of 0 to 0.18 kW / m ２ The symbol S1 indicates the region where the ultrasonic intensity was 0.18 to 0.36 kW / m ２ The symbol S2 indicates the region where the ultrasonic intensity was 0.36 to 0.54 kW / m ２ The symbol S3 indicates the region where the ultrasonic intensity was 0.54 to 0.72 kW / m ２ The symbol S4 indicates the region where the ultrasonic intensity was 0.72 to 0.90 kW / m ２ The symbol S5 indicates the region where the ultrasonic intensity was 0.90 to 1.08 kW / m ２ The symbol S6 indicates the region where the ultrasonic intensity was 1.08 to 1.26 kW / m ２ The symbol S7 indicates the region where the ultrasonic intensity was 1.26 to 1.44 kW / m ２ The symbol S8 indicates the region where the ultrasonic intensity was 1.44 to 1.62 kW / m ２ The symbol S9 indicates the region where the ultrasonic intensity was 1.62 to 1.80 kW / m ２In addition, in a portion where multiple regions where the ultrasonic intensity increases continuously are concentrated in an elliptical shape, the multiple regions may be collectively represented as, for example, "S3 to S9."

[0179] <Test Apparatus 80> As shown in FIG. 17, the test apparatus 80 includes a computer 81, a display 82, an oscilloscope 83, a movable stage 84, an ultrasonic generator 85, a hydrophone 86, a device 87, and a water tank 88.

[0180] The computer 81 has a control unit that controls the testing apparatus 80 overall and a memory unit that stores the conditions and test results of lenses 1 to 4. The display 82 displays the conditions and test results of lenses 1 to 4. The display 82 is connected to the computer 81. The oscilloscope 83 is connected to the hydrophone 86 and acquires signal data detected by the hydrophone 86. The oscilloscope 83 is connected to the computer 81. The movable stage 84 is capable of moving the hydrophone 86 horizontally under the control of the computer 81. The ultrasonic generator 85 has a function generator that generates an electrical signal, such as a sine wave or a square wave, and an amplifier. The ultrasonic generator 85 corresponds, for example, to the apparatus main body 100 shown in FIG. 1. The hydrophone 86 is, for example, a sensor that measures the underwater ultrasonic sound field. The device 87 is replaceable and connected to the ultrasonic generator 85. There are four types of device 87, corresponding to lenses 1 to 4. Each of the four devices 87 is composed of a lens selected from lenses 1 to 4 and a piezoelectric element. Device 87 corresponds to an ultrasonic unit. Water is contained in water tank 88. Device 87 and hydrophone 86 are arranged to face each other in the water of water tank 88.

[0181] In such a test device 80, the hydrophone 86 was moved horizontally by 0.5 mm at a time by driving the movable stage 84, and the ultrasonic wave intensity at each position after the movement was measured.

[0182] <Experimental Results Using Test Device 80> Figures 19, 21, 23, 25, 27, and 29 each show the following experimental results using test device 80. - Figure 19: Experimental results for a comparative example using only a piezoelectric element with a diameter of 6 mm without using a lens (FZP member) - Figure 21: Experimental results for lens 1 - Figure 23: Experimental results for lens 2 - Figure 25: Experimental results for a comparative example using only a piezoelectric element with a diameter of 5 mm without using a lens (FZP member) - Figure 27: Experimental results for lens 3 - Figure 29: Experimental results for lens 4

[0183] In each of the above figures, the horizontal axis indicates the position (mm) on the surface of the body surface. The vertical axis indicates the depth (mm) from the body surface. Here, "body surface" corresponds to the surface of the skin of a living organism. Water is used in the test device 80. The reason for using water is that the physical properties of water are similar to those of skin. "Body surface" corresponds to the interface between the device 87 and water. In other words, it corresponds to the interface between the lens and water. In these experimental results, each of the multiple measured values ​​is normalized. That is, the maximum value is extracted from the multiple measured values ​​indicating ultrasound intensity, and multiple calculated values ​​are obtained by dividing each of the multiple measured values ​​by the maximum value. Therefore, the normalized calculated values ​​are within the range of 0 to 1.0. In each of Figures 19, 21, 23, 25, 27, and 29, symbol V1 indicates the portion where the calculated value was 0 to 0.2. Symbol V2 indicates the portion where the calculated value was 0.2 to 0.4. Symbol V3 indicates the portion where the calculated value was 0.4 to 0.6. Reference symbol V4 indicates the portion where the calculated value was 0.6 to 0.8, and reference symbol V5 indicates the portion where the calculated value was 0.8 to 1.0.

[0184] <Summary> FIG. 30 is a table summarizing the simulation results and experimental results of lenses 1 to 4 for Example 4. FIG. 30 shows the focal depth, focal area, and convergence rate. Here, the focal area refers to the area irradiated with an intensity of 50% or more of the maximum intensity. The convergence rate (dB) is a value obtained by comparing the maximum intensity of each of lenses 1 to 4 with the maximum intensity of a comparative example not equipped with an FZP member.

[0185] (Evaluation Results) The results shown in Figures 18 to 30 revealed the following points: (E1) In the comparative example, the ultrasound intensity was dispersed throughout the entire depth from the body surface. This made it clear that ultrasound could not be focused at a high intensity at the desired depth. (E2) For each of Lenses 1 to 4, a distribution in which ultrasound was focused at a high intensity was achieved. Therefore, it was confirmed that each of Lenses 1 to 4 could create a focal point as expected. (E3) Example 4 uses the FZP member shown in Figure 3B. This FZP member has four connecting portions 23. It was revealed that experimental results close to the simulation results could be obtained regardless of the presence or absence of the four connecting portions 23. (E4) It was revealed that the simulation results and experimental results were approximately the same for the focal depth of Lens 1. In other words, the target value of 3.0 mm could be achieved. (E5) For the focusing ratio of Lens 1, the experimental result was approximately 3.0 dB, indicating a high focusing ratio and that the experimental results could be brought closer to the simulation results. (E6) The focal area of ​​lens 2 can be reduced in both simulation and experimental results. (E7) The diameters of lenses 1 and 2 are each 6.0 mm, and the diameters of lenses 3 and 4 are each 5.0 mm. In other words, lenses 3 and 4 are smaller than lenses 1 and 2. Due to this difference in size, it became clear that adjusting the focusing characteristics of lenses 3 and 4 is difficult.

[0186] 1, 1A, 3, 4, 5, 6 Ultrasonic unit, 10 Piezoelectric element, 10F Ultrasonic wave generating surface, 20 FZP member (transmission type diffraction portion), 20F First FZP surface (first surface), 20S Second FZP surface (second surface), 21 Inner FZP portion, 22 Outer FZP portion, 23 Connecting portion, 25 Slit, 30 Gel member, 30A First gel member, 30B Second gel member, 30F Contact surface, 30S Exposed surface, 31 First urethane resin, 31A Upper surface, 32 Second urethane resin, 32A Liquid upper surface, 35 First gel region, 36 Second gel region, 40 Applied gel, 50, 60 Diffractive gel tape (diffractive swelling tape), 50F, 60F First tape surface, 50S, 60S Second tape surface, 51F First protective sheet, 51S Second protective sheet, 55 Diffractive gel member, 70 base, 70F base surface, 71 frame, 71N frame inner surface, 72 mold, 80 test apparatus, 81 computer, 82 display, 83 oscilloscope, 84 movable stage, 85 ultrasonic generator, 86 hydrophone, 87 device, 88 water tank, 100 apparatus body, 101 AC voltage generator, 102 signal generator, 103 signal cable, 200 ultrasonic focusing device, P1 central opening, P2 peripheral opening, SP slit pattern

Claims

1. A piezoelectric element having an ultrasonic generating surface that generates ultrasonic waves, A transmission-type diffraction section located on or separated from the ultrasonic wave generating surface, Equipped with, Ultrasonic unit.

2. The transmission diffraction section is located on the ultrasonic wave generating surface, The transmission diffraction section is made of a different material from the piezoelectric element. The ultrasonic unit according to claim 1.

3. The device comprises a swelling body provided on the ultrasonic generating surface so as to cover the transmission diffraction portion. The ultrasonic unit according to claim 1 or claim 2.

4. The transmission diffraction section is positioned at a distance from the ultrasonic wave generating surface. The transmission diffraction section has a first surface that is spaced apart from and facing the ultrasonic wave generating surface, and a second surface that is opposite to the first surface. A swelling body is placed at least between the ultrasonic generating surface and the first surface. The swollen body adheres at least the transmission diffraction portion to the piezoelectric element. The ultrasonic unit according to claim 1.

5. The swollen body adheres the transmission diffraction portion to the piezoelectric element so as to cover both the first and second surfaces. The ultrasonic unit according to claim 4.

6. The aforementioned swelling body is A first swelling body is located between the ultrasonic generating surface and the first surface, and the transmission diffraction portion is made to adhere to the piezoelectric element. A second swelling body that is detachable from the second surface, Having, The ultrasonic unit according to claim 4.

7. The swelling body has a contact surface that contacts the ultrasonic generating surface and an exposed surface that is opposite to the contact surface and is exposed to the outside of the ultrasonic unit. In the direction from the contact surface toward the exposed surface, the swelling body located between the first surface and the contact surface has a first thickness, and the swelling body located between the second surface and the exposed surface has a second thickness. By adjusting at least one of the first thickness and the second thickness, the focal distance from the exposed surface to the focal point or the focusing rate of the ultrasound is adjusted. The ultrasonic unit according to any one of claims 4 to 6.

8. The swelling body has a contact surface that contacts the ultrasonic generating surface and an exposed surface that is opposite to the contact surface and is exposed to the outside of the ultrasonic unit. The transmission diffraction section has a slit, By adjusting the width of the slit, the focal distance from the exposed surface to the focal point or the focusing rate of the ultrasound is adjusted. The ultrasonic unit according to any one of claims 4 to 6.

9. The transmission diffraction section is, First member and A second member spaced apart from the first member and surrounding the first member, It has a connecting portion located between the first member and the second member, which connects the first member and the second member. The ultrasonic unit according to claim 1.

10. A diffraction swelling tape used in an ultrasonic unit equipped with a piezoelectric element that generates ultrasonic waves, Support base material and A plurality of diffraction gel members are supported by the support substrate and are arranged in the direction in which the support substrate extends, It has, Each of the plurality of diffraction gel members is A transmission diffraction section having a first surface and a second surface opposite to the first surface, A swelling body that covers at least one of the first and second surfaces and adheres to the piezoelectric element, Equipped with, Diffraction swelling tape.

11. The plurality of diffraction gel members are arranged on the support substrate in a fragmented state. The diffraction swelling tape according to claim 10.

12. The plurality of diffraction gel members are connected by connecting portions formed of the same material as the swollen body. The diffraction swelling tape according to claim 10.

13. Multiple notches are formed to divide the plurality of diffraction gel members into individual ones. The diffraction swelling tape according to claim 10.

14. The first tape surface and The second tape surface, which is opposite to the first tape surface, It has, The aforementioned swelling body is A contact surface that contacts the ultrasonic generating surface of the piezoelectric element, The exposed surface that is exposed to the outside of the ultrasonic unit, It has, Of the first tape surface and the second tape surface, One side is the surface corresponding to the contact surface, The other side is an exposed surface that is exposed to the outside of the ultrasonic unit, The support substrates are a first protective sheet and a second protective sheet. The first protective sheet covers the first tape surface, and the second protective sheet covers the second tape surface, so that the first and second protective sheets protect the plurality of diffraction gel members. The diffraction swelling tape according to claim 10.

15. Ultrasonic unit and A signal generating unit that supplies a frequency signal to the ultrasonic unit, An AC voltage generating unit that supplies AC voltage to the signal generating unit, Equipped with, The aforementioned ultrasonic unit, A piezoelectric element having an ultrasonic generating surface that generates ultrasonic waves, A transmission-type diffraction section located on or separated from the ultrasonic wave generating surface, Equipped with, Ultrasonic focusing device.