Ultrasonic irradiator

Abstract

To provide an ultrasonic irradiator that expands and uniforms a micro bubble generation range, and reduces invasion of an ultrasonic wave to a living body.SOLUTION: A piezoelectric device 1 is driven by AC voltage of a predetermined frequency, and is largely telescopically vibrated to a radial direction as shown by an arrow H. To a lower surface of the piezoelectric device 1, an acoustic vibrator 2 is adhered. The acoustic vibrator 2 includes: an upper circular flat surface 2a that is opposite to the piezoelectric device 1; and a lower concave semispherical surface 2b that is opposite to the upper circular flat surface 2a. At a center of the upper circular flat surface 2a, an upper concaved-like surface 2a-1 for a cymbal structure is formed. At a center of the acoustic vibrator 2, a thin cymbal structure S is formed. Both of lower edge portions 2c and 2d of the lower concave-like semispherical surface 2b are bending-vibrated as shown by an arrow C in accordance with an extension vibration H of a radial direction of the piezoelectric device 1. Bend-vibration C are enhanced by a vertical vibration V of the cymbal structure S.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an ultrasonic irradiator for transdermally transporting a drug, such as an anesthetic, by irradiating ultrasonic waves onto a biological surface such as the skin or mucous membrane. [Background technology]

[0002] Fig. 5 is a diagram showing the principle of an ultrasonic irradiator. In Fig. 5, when ultrasonic waves U are irradiated onto the surface of a living body B, such as skin or mucous membrane, in a medium, such as water W, vibrating microbubbles MB called ultrasonic cavitation bubbles are generated on the surface of the living body B. These microbubbles MB are used to promote the biopermeability of drugs, such as anesthetics, without damaging blood vessels or nerves.

[0003] 5, the ultrasonic waves U are strong enough not to damage the blood vessels, nerves, etc. of the living body B. On the other hand, the microbubbles MB are uniformly distributed over the surface of the living body B and have a large range.

[0004] FIG. 6 is a front view showing a first conventional ultrasonic radiator.

[0005] 6, in order to generate microbubbles MB, a bolt-tightened Langevin transducer (BLT) that generates strong ultrasonic waves is used as the ultrasonic transducer 100. That is, in the ultrasonic transducer 100, an electrode plate 101 is sandwiched between piezoelectric elements 102 and 103, and further, metal bodies 104 and 105 are provided on the outside of the piezoelectric elements 102 and 103. The electrode plate 101 is grounded, and an AC voltage of ±V is applied to the metal bodies 104 and 105. The metal bodies 104 and 105 are mechanically fixed together by bolts (not shown) to provide a robust connection.

[0006] A grip 110 is provided on the upper part of the ultrasonic transducer 100, and an enclosure 120 for holding, for example, water W as a medium is provided on the lower part of the ultrasonic transducer 100.

[0007] In FIG. 6, ultrasonic waves U radiated from radiation surface R on the lower surface of metal body 105 propagate through water W, generating microbubbles MB on the surface of living organism B, and may invade living organism B.

[0008] FIG. 7 is a cross-sectional view showing a second conventional ultrasonic radiator (see Patent Document 1).

[0009] 7, the ultrasonic irradiator is composed of an ultrasonic transducer 201 made of a piezoelectric element, an acoustic propagation body 202 made of a main body 202a and a shaft body 202b provided below the ultrasonic transducer 201, and a grip 203 provided above the ultrasonic transducer 201. The main body 202a is composed of a flat surface 202a-1 joined to the ultrasonic transducer 201, a concave primary reflection surface 202a-2 bulging downward, and a concave secondary reflection surface 202a-3 continuing to the flat surface 202a-1.

[0010] In Figure 7, ultrasound U emitted from the radiation surface R on the bottom surface of the ultrasound transducer 201 enters through the flat surface 202a-1 of the main body 202a, reflects off the primary reflection surface 202a-2, passes through the shaft body 202b, propagates through water (not shown), and is irradiated to cells of the living body B directly below the shaft body 202b.

[0011] FIG. 8 is a cross-sectional view showing a third conventional ultrasonic radiator (see FIG. 5 of Patent Document 2).

[0012] In FIG. 8, the ultrasonic radiator is composed of a hemispherical ultrasonic transducer 302 supported by a backing material 301, a contact layer 303 in contact with the living body B and having a window 303a, and a cavity 304 between the hemispherical ultrasonic transducer 302 and the contact layer 303 and filled with a medium, such as water.

[0013] In FIG. 8, ultrasonic waves U emitted from the radiation surface R on the bottom surface of the hemispherical ultrasonic transducer 302 propagate through the water in the cavity 304, and are concentrated at the window 303a of the contact layer 303, irradiating the cells of the living body B directly below the window 303a. [Prior art documents] [Non-patent literature]

[0014] [Patent Document 1] Patent No. 6774697 [Patent Document 2] Special Publication No. 2002-515786 Summary of the Invention [Problem to be solved by the invention]

[0015] However, in the first conventional ultrasonic irradiator shown in Fig. 6, the ultrasonic transducer 100 has metal bodies 104 and 105 on the top and bottom, so that it is large in the axial direction and difficult to fix to the living body B. Also, as shown in Fig. 9, the effective range R0 of the cavitation effect of the microbubbles MB is limited and non-uniform compared to the radiation surface R of the ultrasonic transducer 100. Furthermore, as shown in Fig. 6, the energy of the ultrasonic waves U is strong, so that it is highly invasive to the living body B, resulting in the risk of complications such as burns, internal bleeding, and nerve damage.

[0016] 7, the ultrasonic transducer 201 can be miniaturized, but the microbubble generation range is limited and non-uniform compared to the radiation surface R of the ultrasonic transducer 201 because it is determined by the shaft body 202b. Furthermore, the energy of the ultrasonic wave U directly below the shaft body 202b is large, so there is still a problem that there is a high risk of invasion to the living body B.

[0017] 8, the ultrasonic transducer 302 can be made smaller, but the ultrasonic waves are concentrated at the window 303a of the contact layer 303 by the hemispherical ultrasonic transducer 302, so the microbubble generation range is determined by the window 303a of the contact layer 303 where the ultrasonic waves U are concentrated, and therefore is limited and non-uniform compared to the radiation surface R of the hemispherical ultrasonic transducer 302. Furthermore, since the energy of the ultrasonic waves U at the window 303a is large, the invasion of the living body B is still large, resulting in a problem of the risk of complications such as burns, internal bleeding, and nerve damage. [Means for solving the problem]

[0018] In order to solve the above-mentioned problems, the ultrasonic irradiator of the present invention comprises a disk-shaped ultrasonic transducer and an acoustic transducer attached to the underside of the ultrasonic transducer, and the acoustic transducer has an upper flat surface facing the ultrasonic transducer and a lower concave hemispherical surface facing the upper flat surface. Effect of the Invention

[0019] According to the present invention, the range in which microbubbles are generated can be expanded by the vibration of the acoustic transducer, and the attenuation of ultrasonic waves by the acoustic transducer can reduce the invasiveness of ultrasonic waves to a living body. [Brief description of the drawings]

[0020] [Figure 1] 1A and 1B show an embodiment of an ultrasonic radiator according to the present invention, in which (A) is a cross-sectional view and (B) is a dimensional view of (A). [Diagram 2] 2A and 2B are views of the ultrasonic radiator in FIG. 1 as viewed from different directions, where (A) is an upper perspective view and (B) is a lower perspective view. [Diagram 3] FIG. 3 is a diagram showing the operating state of the lower edge portion of FIG. 1 and FIG. 2. [Figure 4] FIG. 3 is a diagram for explaining the effective range of the cavitation effect caused by the microbubbles in FIGS. 1 and 2. [Diagram 5] FIG. 1 is a diagram showing the principle of an ultrasonic irradiator. [Figure 6] FIG. 1 is a front view showing a first conventional ultrasonic irradiator. [Figure 7] FIG. 11 is a front view showing a second conventional ultrasonic irradiator. [Figure 8] FIG. 11 is a front view showing a third conventional ultrasonic irradiator. [Figure 9] FIG. 7 is a diagram for explaining the effective range of the cavitation effect caused by the microbubbles MB in FIG. 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] FIG. 1 shows an embodiment of an ultrasonic irradiator according to the present invention, where (A) is a cross-sectional view and (B) is a dimensional drawing of (A), and FIG. 2 shows the ultrasonic irradiator of FIG. 1 from a different direction, where (A) is an oblique view from above and (B) is an oblique view from below.

[0022] In Fig. 1 (A) and (B) and Fig. 2 (A) and (B), an ultrasonic transducer is constructed by providing electrodes 1a, 1b made of, for example, copper, to which an AC voltage from an AC power source AC is applied, on the top and bottom of a piezoelectric element 1 made of, for example, zirconium titanate PZT, ceramic, or polymer, with a thickness of 2 mm and an outer diameter D1 = 28 mm. As described later, the transducer vibrates in the radial direction, eliminating the need for axial bolt tightening and a horn, and as a result, the ultrasonic transducer can be made smaller. The piezoelectric element 1 is driven by an AC voltage of a predetermined frequency, for example, 78 kHz, and vibrates greatly in the radial direction, expanding and contracting, as indicated by the arrow H.

[0023] An acoustic vibrator 2 made of quartz glass, titanium alloy, or the like is bonded to the lower surface of the piezoelectric element 1 by an adhesive (not shown). The acoustic vibrator 2 has an upper circular plane 2a with an outer diameter D2=20.5 mm facing the piezoelectric element 1, and a lower concave hemispherical surface 2b with an opening diameter D3=18.5 mm facing the upper circular plane 2a. An upper concave surface 2a-1 for a cymbal structure is formed at the center of the upper circular plane 2a. In this case, a gap is formed between the piezoelectric element 1 and the upper concave surface 2a-1 for a cymbal structure. Therefore, the periphery of the acoustic vibrator 2 is bonded to the piezoelectric element 1, and a thin cymbal structure S with a thickness of 0.5 mm is formed at the center of the acoustic vibrator 2. As a result, the lower edge portions 2c and 2d of the lower concave hemispherical surface 2b bend and vibrate as shown by the arrow C in accordance with the radial stretching vibration H of the piezoelectric element 1. Moreover, this bending vibration C is enhanced by the presence of the cymbal structure S. That is, the thin cymbal structure S also vibrates vertically as shown by the arrow V, which enhances the bending vibration C.

[0024] FIG. 3 shows the operating state of the lower edge portions 2c and 2d of the acoustic vibrator 2 of FIGS.

[0025] When the piezoelectric element 1 vibrates and contracts in the radial direction, it changes from Fig. 3(A) to Fig. 3(B). That is, the central portion of the acoustic transducer 2 moves upward, and the lower edge portions 2c, 2d move inward. On the other hand, when the piezoelectric element 1 vibrates and expands in the radial direction, it changes from Fig. 3(C) to Fig. 3(D). That is, the central portion of the acoustic transducer 2 moves downward, and the lower edge portions 2c, 2d move outward. In this way, it can be seen that when the piezoelectric element 1 vibrates, the lower edge portions 2c, 2d of the acoustic transducer 2 also move horizontally.

[0026] On the other hand, the opening diameter D3=18.5 mm of the lower concave hemisphere 2b is set to an integer multiple of the half wavelength of the sound wave of the liquid phase of the acoustic transducer 2, for example, water W. This excites acoustic resonance (resonance) in the acoustic transducer 2 filled with the liquid phase. That is, when bending vibration C of the lower edge parts 2c and 2d of the acoustic transducer 2 occurs with the radial vibration H of the piezoelectric element 1, the sound wave sound pressure decreases from the lower concave hemisphere 2b, which acts as the radiating surface of the ultrasonic wave U, toward the surface of the living body B, and a pressure gradient is generated. As a result, the ultrasonic wave U hardly invades the living body B. At the same time, microbubbles MB are generated on the surface of the living body B. These microbubbles MB are diffused and moved in the horizontal direction by the bending vibration C. Therefore, as shown in FIG. 4, the microbubbles MB on the living body B are uniformed, and the effective range R0 of the cavitation effect by the microbubbles MB is expanded compared to the case of FIG. 9.

[0027] In the above-described embodiment, although not shown, for example, the entire device may be housed in a casing with an open bottom, and a grip may be provided on the casing.

[0028] Furthermore, the present invention can be applied to any modifications within the obvious scope of the above-described embodiment. [Industrial Applicability]

[0029] The present invention can be used not only for transdermal drug delivery but also for cleaning semiconductor wafers. [Explanation of symbols]

[0030] 1: Piezoelectric element 1a, 1b: Electrode 2: Acoustic transducer 2a: Upper circular plane 2a-1: Cymbal structure upper concave surface 2b: Lower concave hemisphere 2c, 2d: Edge parts 100: Ultrasonic transducer 101: Electrode plate 102, 103: Piezoelectric element 104, 105: Metal body 110: Grip 120: Enclosure 201: Ultrasonic transducer 202: Acoustic propagation body 202a-1: Flat surface 202a-2: Primary reflective surface 202a-3: Secondary reflective surface 202b: Shaft body 301: Backing material 302: Hemispherical ultrasonic transducer 303: Contact layer 303a: Window 304: Cavity U:Ultrasonic R: Radiation surface B: Living organisms MB: Microbubbles W: Water (medium)

Claims

1. A disk-shaped ultrasonic transducer, an acoustic transducer bonded to the lower surface of the ultrasonic transducer; Equipped with The acoustic transducer is An upper plane facing the ultrasonic transducer; a lower concave hemispherical surface facing the upper flat surface; An ultrasonic irradiator having the above structure.

2. 2. The ultrasonic applicator according to claim 1, further comprising AC driving means for generating a driving signal of a predetermined frequency to the ultrasonic transducer in order to vibrate the ultrasonic transducer in a radial direction.

3. 2. The ultrasonic radiator according to claim 1, wherein an upper concave surface for a cymbal structure is formed in the center of the upper flat surface of the acoustic transducer.

4. 2. The ultrasonic applicator according to claim 1, wherein the opening diameter of the lower concave hemispherical surface of the acoustic transducer is an integer multiple of a half wavelength of a sound wave in a medium when the lower concave hemispherical surface is filled with the medium.

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