WO2020174532A1 - Ultrasound treatment tool - Google Patents

Ultrasound treatment tool Download PDF

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Publication number
WO2020174532A1
WO2020174532A1 PCT/JP2019/007064 JP2019007064W WO2020174532A1 WO 2020174532 A1 WO2020174532 A1 WO 2020174532A1 JP 2019007064 W JP2019007064 W JP 2019007064W WO 2020174532 A1 WO2020174532 A1 WO 2020174532A1
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WO
WIPO (PCT)
Prior art keywords
piezoelectric element
peripheral surface
ultrasonic
liquid
cavity
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PCT/JP2019/007064
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French (fr)
Japanese (ja)
Inventor
伊藤　寛
晋一朗 梅村
晋 吉澤
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オリンパス株式会社
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Priority to PCT/JP2019/007064 priority Critical patent/WO2020174532A1/en
Publication of WO2020174532A1 publication Critical patent/WO2020174532A1/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/22—Implements for squeezing-off ulcers or the like on the inside of inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; Calculus removers; Calculus smashing apparatus; Apparatus for removing obstructions in blood vessels, not otherwise provided for
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N7/00—Ultrasound therapy

Definitions

  • the present invention relates to an ultrasonic treatment tool.
  • transurethral lithotripsy which inserts the tip of a treatment tool into the kidney and urinary tract to crush stones, has become the mainstream.
  • a treatment tool used for transurethral lithotripsy is required to have high lithotripsy performance, and it is also required that the tip has a small diameter and can be inserted through an endoscope channel. ..
  • the mainstream method is to crush stones by inserting an optical fiber into the endoscope channel and guiding a laser into the optical fiber to irradiate the stone. Also, it is possible to crush stones by irradiating the stones with powerful ultrasonic waves, but there is no device yet that can generate ultrasonic waves that are powerful enough to crush stones with a size that can be inserted into the endoscope channel. ..
  • Patent Document 1 describes an ultrasonic treatment instrument having a thin tip and capable of high output.
  • the ultrasonic treatment tool of Patent Document 1 has an ultrasonic transducer formed of a cylindrical piezoelectric element at the tip of the insertion portion, and when the ultrasonic transducer is filled with cooling water, Ultrasound is emitted toward the affected area.
  • the ultrasonic transducer formed of a cylindrical piezoelectric element has a small diameter and is sized to be inserted into a body cavity.
  • Ultrasonic treatment tools used for transurethral lithotripsy require further reduction in diameter and higher output.
  • the cylindrical piezoelectric element is provided inside the balloon in a state of being filled with cooling water, and it is difficult to further reduce the diameter.
  • the balloon and the cooling water become a load for the vibration of the piezoelectric element, and it is difficult to realize a high output.
  • an object of the present invention is to provide an ultrasonic treatment tool having a small diameter and high output.
  • the ultrasonic treatment instrument has a cylindrical shape having a cavity filled with a liquid that propagates ultrasonic waves, and the polarization direction is the thickness direction connecting the inner peripheral surface and the outer peripheral surface.
  • a piezoelectric element and an outer cylinder that holds the piezoelectric element by providing a gas layer on the outer peripheral surface side of the piezoelectric element are provided.
  • the resonance frequency of the respiratory vibration of the piezoelectric element is equal to the resonance frequency of the liquid in the cavity in the radial direction. Good.
  • the ultrasonic treatment tool according to the second aspect even if the ratio of the length in the longitudinal direction of the piezoelectric element to the inner diameter of the piezoelectric element is 3.5 or more. Good.
  • the ultrasonic wave irradiation direction of the piezoelectric element is the distal end side, and the direction opposite to the distal end side in the longitudinal direction is the proximal end side.
  • a second gas layer is formed in the cavity of the piezoelectric element, which serves as a reflection surface for reflecting ultrasonic waves toward a base end side of a division position where the length in the longitudinal direction is divided into two. May be done.
  • the division position may be a position obtained by dividing the length in the longitudinal direction into two equal parts.
  • the ultrasonic treatment instrument of the present invention it is possible to provide an ultrasonic treatment instrument having a small diameter and high output.
  • FIG. 6 is a cross-sectional view of an ultrasonic wave oscillating portion whose internal cavity is filled with a liquid.
  • FIG. 3 is a cross-sectional view of an ultrasonic wave oscillating unit in which a part of the cavity is filled with a liquid. 3 is an XY cross section of a cylindrical liquid filled in the same cavity.
  • FIG. 3 is a schematic diagram of the piezoelectric element of Example 1.
  • FIG. 5 is a schematic diagram of a piezoelectric element of Example 2.
  • FIG. 7 is a schematic diagram of a piezoelectric element of Example 3.
  • FIG. It is a graph which compared the sound pressure distribution in the central axis of a piezoelectric element. It is the graph which normalized the maximum value of sound pressure as 1.
  • FIG. 1 is a diagram showing an overall configuration of a calculus crushing system 300.
  • the calculus breaking system 300 includes an endoscope 200 that is inserted into the urethra U and an ultrasonic treatment instrument 100 that is inserted into a channel of the endoscope 200.
  • the endoscope 200 is appropriately selected from known flexible ureteroscopes including a long endoscope insertion portion 202 having a treatment instrument channel 201 through which a treatment instrument can be inserted.
  • the endoscope 200 has an operation unit 204 at the base end.
  • the operation section 204 is provided with a treatment instrument insertion hole 205, and the ultrasonic treatment instrument 100 is inserted into the treatment instrument channel 201 through the treatment instrument insertion hole 205.
  • FIG. 2 is a perspective view of the tip of the endoscope insertion portion 202 facing the calculus C to be crushed.
  • the endoscope 200 has an illumination 206 and an imaging unit 207 at the tip of the endoscope insertion unit 202.
  • the tip of the ultrasonic treatment instrument 100 inserted into the treatment instrument channel 201 projects from the treatment instrument channel opening 203 at the tip of the endoscope insertion portion 202.
  • the endoscope 200 sends water into the body by discharging the water conveyed via the treatment instrument channel 201 from the treatment instrument channel opening 203.
  • the water discharged from the treatment tool channel opening 203 is perfused through a separately provided drainage channel or the like.
  • the water supply channel and the water supply channel opening are provided in the endoscope 200, and the water conveyed through the water supply channel is discharged into the body by being discharged from the water supply channel opening at the tip of the endoscope 200. Also good.
  • the water discharged from the water supply channel opening is perfused through the treatment tool channel 201, a separately provided drainage channel, and the like.
  • the endoscope 200 is connected to an endoscope system 210 as shown in FIG.
  • the endoscope system 210 includes a light source that provides light to the illumination 206 of the endoscope 200, an image processing circuit that performs image processing on an image captured by the image capturing unit 207, and displays the image on a monitor.
  • the ultrasonic treatment instrument 100 includes an ultrasonic wave oscillating unit 1, an inserting unit 2, and a driving unit 3.
  • the ultrasonic treatment tool 100 is a treatment tool that performs treatment by generating ultrasonic waves from the ultrasonic wave oscillating unit 1 to the affected area.
  • FIG. 3 is a cross-sectional view of the ultrasonic wave oscillating unit 1 of the ultrasonic treatment instrument 100.
  • the ultrasonic wave oscillating unit 1 is a tubular member provided at the tip of the insertion unit 2 and generates ultrasonic waves for the calculus C.
  • the ultrasonic oscillator 1 has a piezoelectric element 11 and an outer cylinder 12.
  • the longitudinal direction of the ultrasonic oscillator 1 is also referred to as the Z-axis direction
  • the plane perpendicular to the Z-axis direction is also referred to as the XY plane.
  • the irradiation direction of ultrasonic waves (one side in the Z-axis direction) is referred to as “tip side”, and the opposite side (the other side in the Z-axis direction) is referred to as “proximal side”.
  • the piezoelectric element 11 is a cylindrical element having a cavity H inside, and is a passive element that utilizes the piezoelectric effect of converting voltage into force.
  • the piezoelectric element 11 is made of, for example, ceramics.
  • the piezoelectric element 11 has a polarization direction in the thickness direction connecting the inner peripheral surface 11i and the outer peripheral surface 11o, and utilizes radial vibration (breathing vibration).
  • the outer cylinder 12 is a cylindrical member provided on the outer peripheral side of the piezoelectric element 11, and has a cylindrical cylinder portion 12s and a tip portion 12d provided at the tip of the cylinder portion 12s.
  • the outer cylinder 12 has only a front end side opening 121 formed at the front end portion 12d and a base end side opening 122 formed at the base end of the cylindrical portion 12s.
  • the tip portion 12d is a disk-shaped member provided at the tip of the cylindrical portion 12s, and has a tip-side opening 121 at the center.
  • the tip portion 12d has a plate thickness direction that matches the longitudinal direction of the cylindrical portion 12s.
  • the peripheral edge portion 121e on the proximal end side of the distal end side opening 121 is tightly sealed with the distal end portion 11d of the piezoelectric element 11 and the adhesive portion 41.
  • the tip-side opening 121 communicates with the cavity H surrounded by the inner peripheral surface 11i of the piezoelectric element 11.
  • the diameter dimension of the front end side opening 121 is substantially equal to the diameter dimension D1 of the inner peripheral surface 11i of the piezoelectric element 11.
  • the diameter dimension D3 of the inner peripheral surface 12i of the outer cylinder 12 is slightly larger than the diameter dimension D2 of the outer peripheral surface 11o of the piezoelectric element 11. Further, the central axis of the outer cylinder 12 in the longitudinal direction coincides with the central axis C of the piezoelectric element 11 in the longitudinal direction. Therefore, between the outer peripheral surface 11o of the piezoelectric element 11 and the inner peripheral surface 12i of the outer cylinder 12, a "gas layer A" in which gas can exist is formed over the entire circumference of the outer peripheral surface 11o of the piezoelectric element 11. ..
  • the insertion portion 2 is a coaxial cable attached to the proximal end side of the ultrasonic wave oscillating portion 1, and a first conductive wire 21 and a second conductive wire 22 for transmitting electric power to the piezoelectric element 11 are inserted therein. ..
  • the first conductive wire 21 is one of the positive electrode and the negative electrode
  • the second conductive wire 22 is the other of the positive electrode and the negative electrode.
  • the tip of the first conductive wire 21 is attached to the inner peripheral surface 11i of the piezoelectric element 11 by the conductive adhesive portion 42. Further, the conductive adhesive portion 42 seals the base end side opening 112 of the piezoelectric element 11. On the other hand, the base end of the first conductive wire 21 is attached to the drive unit 3.
  • the tip of the second conductive wire 22 is attached to the outer peripheral surface 11o of the piezoelectric element 11 and the conductive adhesive portion 43.
  • the base end of the second conductive wire 22 is attached to the drive unit 3.
  • the polarization direction of the piezoelectric element 11 is the thickness direction (radial direction) connecting the inner peripheral surface 11i and the outer peripheral surface 11o.
  • a voltage is applied to the piezoelectric element 11 from the first conductive wire 21 and the second conductive wire 22.
  • the waveform of the applied voltage is a sine wave having a frequency at which radial vibration (breathing vibration) occurs, whereby the piezoelectric element 11 vibrates in the radial direction (breathing vibration) due to the piezoelectric effect.
  • the driving unit 3 is a device that applies a voltage to the piezoelectric element 11 of the ultrasonic oscillator 1 via the first conductive wire 21 and the second conductive wire 22 that are inserted through the insertion unit 2. is there.
  • the drive unit 3 has a switch or the like (not shown), and an operator can operate the switch and control the application of voltage to the piezoelectric element 11.
  • the proximal end opening 122 of the outer cylinder 12 is sealed by the adhesive portion 44 without any gap in a state where only the insertion portion 2 is passed.
  • the gas layer A is sealed on the front end side by the adhesive portion 41 without any gap.
  • the base end side opening 112 of the piezoelectric element 11 is also sealed by the conductive adhesive portion 42 without a gap. That is, the gas layer A is hermetically sealed and is kept watertight even when the ultrasonic wave oscillating unit 1 is immersed in a liquid.
  • FIG. 4 is a cross-sectional view of the ultrasonic wave oscillating unit 1 in which the cavity H is filled with the liquid L.
  • the tip-side opening 121 communicates with the cavity H of the piezoelectric element 11, and when the liquid L such as physiological saline flows from the tip-side opening 121, the liquid L flows into the cavity H. Since the gas layer A is kept watertight, the liquid L does not flow into the gas layer A.
  • the gas layer A formed over the entire circumference of the outer peripheral surface 11o of the piezoelectric element 11 is filled with gas, so that the gas layer A functions as a region that does not transmit ultrasonic waves. This is because the gas filled in the gas layer A hardly transmits ultrasonic waves as compared with the liquid L. Even if the radial dimension of the gas layer A is small, the gas layer A functions as a region that does not transmit ultrasonic waves. It is sufficient that the outer peripheral surface 11o of the piezoelectric element 11 and the inner peripheral surface 12i of the outer cylinder 12 do not come into contact with each other during breathing vibration. The smaller the radial dimension of the gas layer A is, the more suitable it is because the ultrasonic oscillating section 1 has a smaller diameter.
  • FIG. 5 is a cross-sectional view of the ultrasonic wave oscillating unit 1 in which the cavity H is partially filled with the liquid L.
  • a predetermined amount of gas remains without being discharged when the liquid flows in, and the second gas layer A2 is formed inside the cavity H.
  • the second gas layer A2 is arranged on the base end side by the pressure of the liquid L.
  • the boundary between the liquid L and the second gas layer A2 functions as a reflection surface R that reflects ultrasonic waves.
  • the reflecting surface R reflects ultrasonic waves toward the tip side, and the generated ultrasonic waves are emitted toward the calculus C to be crushed.
  • FIG. 6 is an XY cross section of the cylindrical liquid L filling the entire cavity H as shown in FIG.
  • the equation of motion of the resonant vibration in the radial direction of the liquid L is expressed by Equation 1.
  • Expression 1 is expanded into Expression 2, and Expression 3 is derived.
  • J 1 is a first-order Bessel function of the first kind (see FIG. 7), and u 0 is an arbitrary constant determined by boundary conditions.
  • the minimum resonance diameter 2r 0 of the distance (resonance diameter) at which the displacement u is maximized is calculated as in Expressions 4 and 5.
  • FIG. 8 is an XY cross section of the piezoelectric element 11.
  • the piezoelectric element 11 when the distance a from the central axis C, the radial displacement u, the elastic constant E of the piezoelectric element 11, the sound velocity ks of the piezoelectric element 11, the Poisson's ratio ⁇ , the density ⁇ , and the time t are given,
  • the equation of motion of the resonance vibration in the radial direction is expressed by Equation 6.
  • the piezoelectric element 11 is modeled as a cylinder having a very thin thickness.
  • Equation 6 is derived from Equation 6.
  • Cs is represented by Expression 8.
  • Equation 10 the ratio between the resonance diameter 2r 0 of the liquid L and the resonance diameter 2a of the piezoelectric element 11 is expressed by Equation 10.
  • the piezoelectric element 11 formed thinly of ceramics and the cylindrical liquid L having an outer diameter equal to the inner diameter of the piezoelectric element 11 resonate. That is, the resonance frequency of the respiratory vibration of the piezoelectric element 11 is equal to the resonance frequency of the liquid L in the cavity H in the radial direction.
  • the resonance frequency of the respiratory vibration of the piezoelectric element 11 is equivalent to the resonance frequency of the liquid L in the cavity H in the radial direction means that they both substantially coincide with each other to the extent that resonance occurs.
  • the lengths of the piezoelectric element 11 and the cylindrical liquid L in the longitudinal direction be sufficiently larger than the diameter of the piezoelectric element 11.
  • FIG. 9 is a sectional view of an ideal baffled piezoelectric element 11A.
  • the outer cylinder 12 is not provided on the outer circumference of the piezoelectric element 11A.
  • the piezoelectric element 11A is provided with an ideal baffle that does not become a load on the piezoelectric element 11A, and the liquid L does not flow into the outer periphery of the piezoelectric element 11A without the outer cylinder 12, and the outer periphery of the piezoelectric element 11A is A gas layer A is formed on the surface side.
  • FIG. 10 is a sectional view of the piezoelectric element 11 with the outer cylinder 12.
  • the piezoelectric element 11 is held by the outer cylinder 12, and the gas layer A is formed between the outer peripheral surface 11o of the piezoelectric element 11 and the inner peripheral surface 12i of the outer cylinder 12 over the entire outer peripheral surface 11o of the piezoelectric element 11. It is formed.
  • the thickness of the piezoelectric element was set to 1/5 of the inner diameter of the piezoelectric element.
  • FIG. 11 is a simulation result regarding the relationship between the aspect ratio of the piezoelectric element and the acoustic output.
  • the piezoelectric element 11 with the outer cylinder 12 is smaller than the piezoelectric element 11A with a baffle. Also has a higher sound output.
  • the piezoelectric element 11 with the outer cylinder 12 has a substantially constant value when the ratio of the length in the longitudinal direction of the piezoelectric element 11 to the length of the average diameter of the piezoelectric element 11 is 3.5 or more.
  • the operator causes the ultrasonic wave oscillating section 1 of the ultrasonic treatment instrument 100 to protrude from the treatment instrument channel opening 203 at the tip of the endoscope insertion section 202, as shown in FIG.
  • the surgeon further brings the tip-side opening 121 of the ultrasonic wave oscillating unit 1 closer to the calculus C to be crushed, while checking the image displayed on the monitor.
  • the physiological saline sent from the treatment instrument channel opening 203 flows in from the distal end side opening 121.
  • the cavity H surrounded by the inner peripheral surface 11i of the piezoelectric element 11 is filled with the liquid L.
  • the outer peripheral surface 11o of the piezoelectric element 11 is still surrounded by the gas layer A over the entire circumference.
  • the operator may leave a predetermined amount of gas in the cavity H to form the second gas layer A2.
  • the surgeon operates a switch or the like provided on the drive unit 3 to apply a voltage to the piezoelectric element 11.
  • the piezoelectric element 11 breathes and vibrates in the radial direction by the piezoelectric effect to generate ultrasonic waves.
  • the generated ultrasonic waves are emitted to the tip side from the tip side opening 121 via the liquid L filled in the cavity H.
  • the outer peripheral surface 11o of the piezoelectric element 11 is surrounded by the gas layer A over the entire circumference, it is difficult for ultrasonic waves to propagate. Therefore, most of the generated ultrasonic waves are emitted to the tip side from the tip side opening 121. Therefore, the generated ultrasonic waves can be emitted toward the calculus C to be crushed without loss.
  • the ultrasonic treatment device 100 of this embodiment since the outer peripheral surface 11o of the piezoelectric element 11 is surrounded by the gas layer A over the entire circumference, it is difficult for ultrasonic waves to propagate. Therefore, most of the generated ultrasonic waves are emitted to the tip side from the tip side opening 121. Therefore, the generated ultrasonic waves can be emitted toward the calculus C to be crushed without loss.
  • the reflecting surface R reflects the ultrasonic wave toward the tip side, and the ultrasonic wave is preferably stoned. Can be transmitted to C.
  • the piezoelectric element 11 has a tubular shape and has a low impedance even when the diameter is reduced, and it is easy to obtain a high output ultrasonic wave with a low driving voltage. Further, the gas layer A formed on the outer peripheral surface 11o of the piezoelectric element 11 exhibits a function of not transmitting ultrasonic waves even when formed thin. Therefore, even when the gas layer A is formed on the outer peripheral surface 11o of the piezoelectric element 11, the ultrasonic wave oscillating portion 1 can be suitably thinned.
  • the piezoelectric element 11 is made of ceramic, but the piezoelectric element according to the present invention is not limited to this.
  • the piezoelectric element according to the present invention may be formed of a passive element other than ceramic, for example, a piezoelectric single crystal.
  • the piezoelectric element 11 and the outer cylinder 12 are formed in a cylindrical shape, but the piezoelectric element and the outer cylinder according to the present invention are not limited to this.
  • the piezoelectric element and the outer cylinder according to the present invention may be formed in a rectangular tube shape, for example.
  • FIG. 12 is a schematic diagram of the piezoelectric element 11 according to the first embodiment.
  • Example 1 is a piezoelectric element 11 having a longitudinal length of 3 mm, an inner diameter of 0.8 mm, and an outer diameter of 1.0 mm.
  • the outer periphery of the piezoelectric element 11 of Example 1 is in contact with the air layer A. Further, the cavity H is completely filled with the liquid L.
  • FIG. 13 is a schematic diagram of the piezoelectric element 11 according to the second embodiment.
  • Example 2 is a piezoelectric element 11 having a longitudinal length of 3 mm, an inner diameter of 0.8 mm, and an outer diameter of 1.0 mm.
  • the outer periphery of the piezoelectric element 11 of Example 2 is in contact with the air layer A.
  • half of the cavity H is filled with the liquid L, and the second gas layer A2 is formed in the half on the base end side.
  • a reflective surface R is formed at the boundary between the liquid L and the second gas layer A2.
  • FIG. 14 is a schematic diagram of the piezoelectric element 11 according to the third embodiment.
  • Example 1 is a piezoelectric element 11 having a longitudinal length of 1.5 mm, an inner diameter of 0.8 mm, and an outer diameter of 1.0 mm.
  • the outer periphery of the piezoelectric element 11 of Example 1 is in contact with the air layer A. Further, the cavity H is completely filled with the liquid L.
  • a simulation for calculating the acoustic output was performed using Examples 1-3.
  • the liquid L is water and the piezoelectric element 11 is made of ceramics.
  • the drive voltage of the piezoelectric element 11 was set to 1V.
  • the Z-axis was defined as the origin where the tip side opening of the piezoelectric element 11 was located.
  • FIG. 15 is a graph comparing the sound pressure distributions on the central axis C of the piezoelectric element 11.
  • FIG. 16 is a graph in which the maximum value of sound pressure is normalized to 1. As shown in FIG. 15, the maximum value of the sound pressure is highest in Example 1 and lowest in Example 3. In any of the examples, the sound pressure is highest near the center of the region where the liquid L is located.
  • Example 2 Since the resonance resistance of the second embodiment is larger than that of the first embodiment, the absolute value of the sound pressure at the tip side opening is lowered. However, the sound pressure difference between the tip side opening and the sound pressure maximum portion is small. In Example 2, as compared with Example 3, the sound pressure difference between the tip side opening and the sound pressure maximum portion is substantially the same, but the absolute value of the sound pressure at the tip side opening is high.
  • the piezoelectric element 11 according to the second embodiment has a well-balanced configuration in terms of sound pressure at the tip-side opening and sound pressure difference between the tip-side opening and the central portion. Be considered.
  • the present invention can be applied to a medical manipulator having a curved portion.

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Abstract

This ultrasound treatment tool comprises: a piezoelectric element that has a cylindrical shape having therein a cavity filled with a liquid that propagates ultrasound, and in which the polarization direction is the thickness direction connecting an inner peripheral surface to an outer peripheral surface; and an outer cylinder that retains the piezoelectric element with a gas layer provided on the outer peripheral surface side of the piezoelectric element. The piezoelectric element respiration-oscillation resonant frequency may be equivalent to the resonant frequency in the radial direction of the liquid in the cavity. The ratio of the length of the piezoelectric element in the lengthwise direction in relation to the inner diameter of the piezoelectric element may be 3.5 or greater.

Description

超音波処置具Ultrasonic treatment tool
　本発明は、超音波処置具に関する。 The present invention relates to an ultrasonic treatment tool.
　腎臓、尿路に形成された結石を破砕する尿路結石治療においては、腎臓、尿路内に処置具の先端部を挿入して結石を破砕する経尿道的結石破砕術が主流となってきている。経尿道的結石破砕術に用いる処置具は、結石破砕性能が高いことが必要とされており、また、先端が細径であり内視鏡のチャネルを挿通可能であることも必要とされている。 In the treatment of urinary calculi that crush stones formed in the kidney and urinary tract, transurethral lithotripsy, which inserts the tip of a treatment tool into the kidney and urinary tract to crush stones, has become the mainstream. There is. A treatment tool used for transurethral lithotripsy is required to have high lithotripsy performance, and it is also required that the tip has a small diameter and can be inserted through an endoscope channel. ..
　経尿道的結石破砕術では、内視鏡チャネルに光ファイバーを挿通し、光ファイバー内にレーザーを導光して結石に照射することにより結石を破砕する方法が主流となっている。また、強力な超音波を結石に照射すれば結石を破砕することが可能であるが、内視鏡チャネルに挿通可能なサイズで結石を破砕できるほどの強力超音波を発生できるデバイスはまだ存在しない。 In transurethral lithotripsy, the mainstream method is to crush stones by inserting an optical fiber into the endoscope channel and guiding a laser into the optical fiber to irradiate the stone. Also, it is possible to crush stones by irradiating the stones with powerful ultrasonic waves, but there is no device yet that can generate ultrasonic waves that are powerful enough to crush stones with a size that can be inserted into the endoscope channel. ..
　特許文献１には、先端が細径であり、高出力が可能な超音波処置具が記載されている。特許文献１の超音波処置具は、円筒形状の圧電素子からなる超音波振動子を挿入部の先端に有しており、超音波振動子を冷却水に満たした状態で、超音波振動子から超音波を患部に向けて放射する。円筒形状の圧電素子からなる超音波振動子は、径寸法が小さく形成されており、体腔内に挿入可能な大きさになっている。 [Patent Document 1] describes an ultrasonic treatment instrument having a thin tip and capable of high output. The ultrasonic treatment tool of Patent Document 1 has an ultrasonic transducer formed of a cylindrical piezoelectric element at the tip of the insertion portion, and when the ultrasonic transducer is filled with cooling water, Ultrasound is emitted toward the affected area. The ultrasonic transducer formed of a cylindrical piezoelectric element has a small diameter and is sized to be inserted into a body cavity.
特開平５－６８６８４号公報JP-A-5-68684
　経尿道的結石破砕術に用いる超音波処置具は、さらなる細径化、高出力化が必要とされている。しかしながら、特許文献１の超音波処置具は、円筒形状の圧電素子がバルーンの内部において冷却水に満たされた状態で設けられており、さらなる細径化が難しかった。また、特許文献１の超音波処置具は、バルーンおよび冷却水が圧電素子の振動にとって負荷となってしまい、高出力を実現することが難しかった。 Ultrasonic treatment tools used for transurethral lithotripsy require further reduction in diameter and higher output. However, in the ultrasonic treatment tool of Patent Document 1, the cylindrical piezoelectric element is provided inside the balloon in a state of being filled with cooling water, and it is difficult to further reduce the diameter. Moreover, in the ultrasonic treatment tool of Patent Document 1, the balloon and the cooling water become a load for the vibration of the piezoelectric element, and it is difficult to realize a high output.
　上記事情を踏まえ、本発明は、細径かつ高出力な超音波処置具を提供することを目的とする。 In view of the above circumstances, an object of the present invention is to provide an ultrasonic treatment tool having a small diameter and high output.
　上記課題を解決するために、この発明は以下の手段を提案している。
　本発明の第一の態様に係る超音波処置具は、超音波を伝搬させる液体が充填される空洞を内部に有する筒形状であり、分極方向が内周面と外周面とを結ぶ厚み方向である圧電素子と、前記圧電素子の外周面側に気体層を設けて前記圧電素子を保持する外筒と、を備える。 In order to solve the above problems, the present invention proposes the following means.
The ultrasonic treatment instrument according to the first aspect of the present invention has a cylindrical shape having a cavity filled with a liquid that propagates ultrasonic waves, and the polarization direction is the thickness direction connecting the inner peripheral surface and the outer peripheral surface. A piezoelectric element and an outer cylinder that holds the piezoelectric element by providing a gas layer on the outer peripheral surface side of the piezoelectric element are provided.
　本発明の第二の態様によれば、第一の態様に係る超音波処置具において、前記圧電素子の呼吸振動の共振周波数は、空洞内の液体の半径方向の共振周波数と同等であってもよい。 According to a second aspect of the present invention, in the ultrasonic treatment tool according to the first aspect, the resonance frequency of the respiratory vibration of the piezoelectric element is equal to the resonance frequency of the liquid in the cavity in the radial direction. Good.
　本発明の第三の態様によれば、第二の態様に係る超音波処置具において、前記圧電素子の内径に対する前記圧電素子の長手方向の長さの比は、３．５以上であってもよい。 According to the third aspect of the present invention, in the ultrasonic treatment tool according to the second aspect, even if the ratio of the length in the longitudinal direction of the piezoelectric element to the inner diameter of the piezoelectric element is 3.5 or more. Good.
　本発明の第四の態様によれば、第一の態様に係る超音波処置具において、前記圧電素子の超音波の照射方向を先端側、前記先端側と長手方向に対向する方向を基端側とし、
　前記圧電素子の前記空洞は、前記液体が充填された状態において、前記長手方向の長さを２分割した分割位置よりも基端側に超音波を反射する反射面となる第二気体層が形成されてもよい。 According to a fourth aspect of the present invention, in the ultrasonic treatment tool according to the first aspect, the ultrasonic wave irradiation direction of the piezoelectric element is the distal end side, and the direction opposite to the distal end side in the longitudinal direction is the proximal end side. age,
In the cavity filled with the liquid, a second gas layer is formed in the cavity of the piezoelectric element, which serves as a reflection surface for reflecting ultrasonic waves toward a base end side of a division position where the length in the longitudinal direction is divided into two. May be done.
　本発明の第五の態様によれば、第四の態様に係る超音波処置具のおいて、前記分割位置は、前記長手方向の長さを２等分割した位置であってもよい。 According to the fifth aspect of the present invention, in the ultrasonic treatment tool according to the fourth aspect, the division position may be a position obtained by dividing the length in the longitudinal direction into two equal parts.
　本発明の超音波処置具によれば、細径かつ高出力な超音波処置具を提供することができる。 According to the ultrasonic treatment instrument of the present invention, it is possible to provide an ultrasonic treatment instrument having a small diameter and high output.
本発明の一実施形態に係る超音波処置具を備える結石破砕システムの全体構成を示す図である。It is a figure which shows the whole structure of the calculus crushing system provided with the ultrasonic treatment tool which concerns on one Embodiment of this invention. 破砕対象の結石と対向する内視鏡挿入部の先端の斜視図である。It is a perspective view of the tip of the endoscope insertion part which opposes the calculus of a crushing object. 同超音波処置具の超音波発振部の断面図である。It is sectional drawing of the ultrasonic wave oscillating part of the same ultrasonic treatment tool. 内部の空洞が液体で満たされた超音波発振部の断面図である。FIG. 6 is a cross-sectional view of an ultrasonic wave oscillating portion whose internal cavity is filled with a liquid. 同空洞の一部が液体で満たされた超音波発振部の断面図である。FIG. 3 is a cross-sectional view of an ultrasonic wave oscillating unit in which a part of the cavity is filled with a liquid. 同空洞に充填された円柱状の液体のＸＹ断面である。3 is an XY cross section of a cylindrical liquid filled in the same cavity. １次の第１種ベッセル関数を示すグラフである。It is a graph which shows the 1st-order Bessel function of the 1st kind. 同超音波発振部の圧電素子のＸＹ断面である。3 is an XY cross section of the piezoelectric element of the ultrasonic oscillator. 理想的なバッフル付き圧電素子の断面図である。It is sectional drawing of an ideal piezoelectric element with a baffle. 外筒付き圧電素子の断面図である。It is sectional drawing of the piezoelectric element with an outer cylinder. 圧電素子のアスペクト比と音響出力との関係に関するシミュレーション結果である。It is a simulation result regarding the relationship between the aspect ratio of a piezoelectric element and acoustic output. 実施例１の圧電素子の模式図である。3 is a schematic diagram of the piezoelectric element of Example 1. FIG. 実施例２の圧電素子の模式図である。5 is a schematic diagram of a piezoelectric element of Example 2. FIG. 実施例３の圧電素子の模式図である。7 is a schematic diagram of a piezoelectric element of Example 3. FIG. 圧電素子の中心軸における音圧分布を比較したグラフである。It is a graph which compared the sound pressure distribution in the central axis of a piezoelectric element. 音圧の最大値を１として正規化したグラフである。It is the graph which normalized the maximum value of sound pressure as 1.
　本発明の一実施形態に係る超音波処置具１００について、図１から図１１を参照して以下に説明する。 An ultrasonic treatment device 100 according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 11.
［結石破砕システム３００］
　図１は、結石破砕システム３００の全体構成を示す図である。
　結石破砕システム３００は、図１に示すように、尿道Ｕに挿入される内視鏡２００と、内視鏡２００のチャネルに挿通される超音波処置具１００と、を備えている。 [Stone crushing system 300]
FIG. 1 is a diagram showing an overall configuration of a calculus crushing system 300.
As shown in FIG. 1, the calculus breaking system 300 includes an endoscope 200 that is inserted into the urethra U and an ultrasonic treatment instrument 100 that is inserted into a channel of the endoscope 200.
［内視鏡２００］
　内視鏡２００は、処置具が挿通可能な処置具チャネル２０１を有する長尺の内視鏡挿入部２０２を備えた公知の軟性尿管鏡の中から、適宜選択したものである。内視鏡２００は、基端に操作部２０４を有している。操作部２０４には処置具挿入孔２０５が設けられており、処置具挿入孔２０５から超音波処置具１００が処置具チャネル２０１に挿入される。 [Endoscope 200]
The endoscope 200 is appropriately selected from known flexible ureteroscopes including a long endoscope insertion portion 202 having a treatment instrument channel 201 through which a treatment instrument can be inserted. The endoscope 200 has an operation unit 204 at the base end. The operation section 204 is provided with a treatment instrument insertion hole 205, and the ultrasonic treatment instrument 100 is inserted into the treatment instrument channel 201 through the treatment instrument insertion hole 205.
　図２は、破砕対象の結石Ｃと対向する内視鏡挿入部２０２の先端の斜視図である。
　内視鏡２００は、内視鏡挿入部２０２の先端に照明２０６や撮像部２０７を有している。処置具チャネル２０１に挿入された超音波処置具１００の先端は、内視鏡挿入部２０２の先端の処置具チャネル開口２０３から突出する。 FIG. 2 is a perspective view of the tip of the endoscope insertion portion 202 facing the calculus C to be crushed.
The endoscope 200 has an illumination 206 and an imaging unit 207 at the tip of the endoscope insertion unit 202. The tip of the ultrasonic treatment instrument 100 inserted into the treatment instrument channel 201 projects from the treatment instrument channel opening 203 at the tip of the endoscope insertion portion 202.
　内視鏡２００は、処置具チャネル２０１を経由して搬送された水が、処置具チャネル開口２０３から排出されることで、体内に送水を行う。処置具チャネル開口２０３から排出された水は、別途に設けられた排水チャネル等を経由して灌流する。
　なお、内視鏡２００に、送水チャネル、送水チャネル開口を設けて、送水チャネルを経由して搬送された水が、内視鏡２００先端の送水チャネル開口から排出されることによって体内に送水することとしても良い。この場合、送水チャネル開口から排出された水は、処置具チャネル２０１や別途設けられた排水チャネル等を経由して灌流する。 The endoscope 200 sends water into the body by discharging the water conveyed via the treatment instrument channel 201 from the treatment instrument channel opening 203. The water discharged from the treatment tool channel opening 203 is perfused through a separately provided drainage channel or the like.
It should be noted that the water supply channel and the water supply channel opening are provided in the endoscope 200, and the water conveyed through the water supply channel is discharged into the body by being discharged from the water supply channel opening at the tip of the endoscope 200. Also good. In this case, the water discharged from the water supply channel opening is perfused through the treatment tool channel 201, a separately provided drainage channel, and the like.
　内視鏡２００は、図1に示すように、内視鏡システム２１０に接続されている。内視鏡システム２１０は、内視鏡２００の照明２０６に光を提供する光源や、撮像部２０７が撮像した画像を画像処理してモニタに表示する画像処理回路等を備えている。 The endoscope 200 is connected to an endoscope system 210 as shown in FIG. The endoscope system 210 includes a light source that provides light to the illumination 206 of the endoscope 200, an image processing circuit that performs image processing on an image captured by the image capturing unit 207, and displays the image on a monitor.
［超音波処置具１００］
　超音波処置具１００は、超音波発振部１と、挿入部２と、駆動部３と、を備えている。超音波処置具１００は、超音波発振部１から患部に対して超音波を発生させて処置を行う処置具である。 [Ultrasonic treatment tool 100]
The ultrasonic treatment instrument 100 includes an ultrasonic wave oscillating unit 1, an inserting unit 2, and a driving unit 3. The ultrasonic treatment tool 100 is a treatment tool that performs treatment by generating ultrasonic waves from the ultrasonic wave oscillating unit 1 to the affected area.
　図３は、超音波処置具１００の超音波発振部１の断面図である。
　超音波発振部１は、挿入部２の先端に設けられた筒形状の部材であり、結石Ｃに対して超音波を発生させる。超音波発振部１は、圧電素子１１と、外筒１２と、を有している。
　以降の説明において、超音波発振部１の長手方向をＺ軸方向、Ｚ軸方向に垂直な平面をＸＹ平面とも称す。また、超音波発振部１において、超音波の照射方向（Ｚ軸方向の一方側）を「先端側」、その反対側（Ｚ軸方向の他方側）を「基端側」と称す。 FIG. 3 is a cross-sectional view of the ultrasonic wave oscillating unit 1 of the ultrasonic treatment instrument 100.
The ultrasonic wave oscillating unit 1 is a tubular member provided at the tip of the insertion unit 2 and generates ultrasonic waves for the calculus C. The ultrasonic oscillator 1 has a piezoelectric element 11 and an outer cylinder 12.
In the following description, the longitudinal direction of the ultrasonic oscillator 1 is also referred to as the Z-axis direction, and the plane perpendicular to the Z-axis direction is also referred to as the XY plane. Further, in the ultrasonic wave oscillating unit 1, the irradiation direction of ultrasonic waves (one side in the Z-axis direction) is referred to as “tip side”, and the opposite side (the other side in the Z-axis direction) is referred to as “proximal side”.
　圧電素子１１は、空洞Ｈを内部に有する円筒形状であり、電圧を力に変換する圧電効果を利用した受動素子である。圧電素子１１は、例えばセラミックスで形成されている。圧電素子１１は、分極方向が内周面１１ｉと外周面１１ｏとを結ぶ厚み方向であり、径方向の振動（呼吸振動）を利用する。 The piezoelectric element 11 is a cylindrical element having a cavity H inside, and is a passive element that utilizes the piezoelectric effect of converting voltage into force. The piezoelectric element 11 is made of, for example, ceramics. The piezoelectric element 11 has a polarization direction in the thickness direction connecting the inner peripheral surface 11i and the outer peripheral surface 11o, and utilizes radial vibration (breathing vibration).
　外筒１２は、圧電素子１１の外周側に設けられた円筒状部材であり、円筒状の筒部１２ｓと、筒部１２ｓの先端に設けられた先端部１２ｄと、を有している。外筒１２は、先端部１２ｄに形成された先端側開口１２１と、筒部１２ｓの基端に形成された基端側開口１２２のみが開口している。 The outer cylinder 12 is a cylindrical member provided on the outer peripheral side of the piezoelectric element 11, and has a cylindrical cylinder portion 12s and a tip portion 12d provided at the tip of the cylinder portion 12s. The outer cylinder 12 has only a front end side opening 121 formed at the front end portion 12d and a base end side opening 122 formed at the base end of the cylindrical portion 12s.
　先端部１２ｄは、筒部１２ｓの先端に設けられた円盤状部材であり、中心に先端側開口１２１を有する。先端部１２ｄは、板厚方向が筒部１２ｓの長手方向と一致している。 The tip portion 12d is a disk-shaped member provided at the tip of the cylindrical portion 12s, and has a tip-side opening 121 at the center. The tip portion 12d has a plate thickness direction that matches the longitudinal direction of the cylindrical portion 12s.
　先端側開口１２１の基端側の周縁部１２１ｅは、圧電素子１１の先端部１１ｄと、接着部４１によって隙間なく封止されている。先端側開口１２１は、圧電素子１１の内周面１１ｉに囲まれた空洞Ｈに連通している。先端側開口１２１の径寸法は、圧電素子１１の内周面１１ｉの径寸法Ｄ１と略一致している。 The peripheral edge portion 121e on the proximal end side of the distal end side opening 121 is tightly sealed with the distal end portion 11d of the piezoelectric element 11 and the adhesive portion 41. The tip-side opening 121 communicates with the cavity H surrounded by the inner peripheral surface 11i of the piezoelectric element 11. The diameter dimension of the front end side opening 121 is substantially equal to the diameter dimension D1 of the inner peripheral surface 11i of the piezoelectric element 11.
　図３に示すように、外筒１２の内周面１２ｉの径寸法Ｄ３は、圧電素子１１の外周面１１ｏの径寸法Ｄ２よりわずかに大きい。また、外筒１２の長手方向の中心軸は、圧電素子１１の長手方向の中心軸Ｃと一致している。そのため、圧電素子１１の外周面１１ｏと外筒１２の内周面１２ｉとの間には、圧電素子１１の外周面１１ｏの全周にわたって、気体が存在可能な「気体層Ａ」が形成される。 As shown in FIG. 3, the diameter dimension D3 of the inner peripheral surface 12i of the outer cylinder 12 is slightly larger than the diameter dimension D2 of the outer peripheral surface 11o of the piezoelectric element 11. Further, the central axis of the outer cylinder 12 in the longitudinal direction coincides with the central axis C of the piezoelectric element 11 in the longitudinal direction. Therefore, between the outer peripheral surface 11o of the piezoelectric element 11 and the inner peripheral surface 12i of the outer cylinder 12, a "gas layer A" in which gas can exist is formed over the entire circumference of the outer peripheral surface 11o of the piezoelectric element 11. ..
　挿入部２は、超音波発振部１の基端側に取り付けられた同軸ケーブルであり、内部には圧電素子１１に電力を伝達する第一導電線２１および第二導電線２２が挿通している。第一導電線２１が正極または負極の一方であり、第二導電線２２が正極または負極の他方である。 The insertion portion 2 is a coaxial cable attached to the proximal end side of the ultrasonic wave oscillating portion 1, and a first conductive wire 21 and a second conductive wire 22 for transmitting electric power to the piezoelectric element 11 are inserted therein. .. The first conductive wire 21 is one of the positive electrode and the negative electrode, and the second conductive wire 22 is the other of the positive electrode and the negative electrode.
　第一導電線２１の先端は、圧電素子１１の内周面１１ｉと導線性接着部４２により取り付けられている。また、導線性接着部４２は、圧電素子１１の基端側開口１１２を封止している。一方、第一導電線２１の基端は、駆動部３に取り付けられている。 The tip of the first conductive wire 21 is attached to the inner peripheral surface 11i of the piezoelectric element 11 by the conductive adhesive portion 42. Further, the conductive adhesive portion 42 seals the base end side opening 112 of the piezoelectric element 11. On the other hand, the base end of the first conductive wire 21 is attached to the drive unit 3.
　第二導電線２２の先端は、圧電素子１１の外周面１１ｏと導線性接着部４３により取り付けられている。一方、第二導電線２２の基端は、駆動部３に取り付けられている。 The tip of the second conductive wire 22 is attached to the outer peripheral surface 11o of the piezoelectric element 11 and the conductive adhesive portion 43. On the other hand, the base end of the second conductive wire 22 is attached to the drive unit 3.
　圧電素子１１の分極方向は、内周面１１ｉと外周面１１ｏとを結ぶ厚み方向（径方向）となる。圧電素子１１は、第一導電線２１および第二導電線２２から電圧が加えられる。印加電圧の波形は、径方向の振動（呼吸振動）が生じる周波数の正弦波で、これにより圧電素子１１は、圧電効果により径方向に振動（呼吸振動）する。 The polarization direction of the piezoelectric element 11 is the thickness direction (radial direction) connecting the inner peripheral surface 11i and the outer peripheral surface 11o. A voltage is applied to the piezoelectric element 11 from the first conductive wire 21 and the second conductive wire 22. The waveform of the applied voltage is a sine wave having a frequency at which radial vibration (breathing vibration) occurs, whereby the piezoelectric element 11 vibrates in the radial direction (breathing vibration) due to the piezoelectric effect.
　駆動部３は、図1に示すように、挿入部２を挿通する第一導電線２１および第二導電線２２を経由して、超音波発振部１の圧電素子１１に電圧を印加する装置である。駆動部３は、不図示のスイッチ等を有しており、術者がスイッチを操作すること、圧電素子１１への電圧の印加を制御することができる。 As shown in FIG. 1, the driving unit 3 is a device that applies a voltage to the piezoelectric element 11 of the ultrasonic oscillator 1 via the first conductive wire 21 and the second conductive wire 22 that are inserted through the insertion unit 2. is there. The drive unit 3 has a switch or the like (not shown), and an operator can operate the switch and control the application of voltage to the piezoelectric element 11.
　外筒１２の基端側開口１２２は、図３に示すように、挿入部２のみを通過させた状態で、接着部４４によって隙間なく封止されている。また、気体層Ａは、先端側が接着部４１によって隙間なく封止されている。また、圧電素子１１の基端側開口１１２も導線性接着部４２によって隙間なく封止されている。すなわち、気体層Ａは密閉されており、超音波発振部１が液体に浸された状態となった場合も水密に保たれる。 As shown in FIG. 3, the proximal end opening 122 of the outer cylinder 12 is sealed by the adhesive portion 44 without any gap in a state where only the insertion portion 2 is passed. In addition, the gas layer A is sealed on the front end side by the adhesive portion 41 without any gap. Further, the base end side opening 112 of the piezoelectric element 11 is also sealed by the conductive adhesive portion 42 without a gap. That is, the gas layer A is hermetically sealed and is kept watertight even when the ultrasonic wave oscillating unit 1 is immersed in a liquid.
　図４は、空洞Ｈが液体Ｌで満たされた超音波発振部１の断面図である。
　先端側開口１２１は圧電素子１１の空洞Ｈと連通しており、先端側開口１２１から生理食塩水等の液体Ｌが流入した場合、液体Ｌは空洞Ｈに流入する。気体層Ａは水密に保たれているため、液体Ｌは気体層Ａに流入しない。 FIG. 4 is a cross-sectional view of the ultrasonic wave oscillating unit 1 in which the cavity H is filled with the liquid L.
The tip-side opening 121 communicates with the cavity H of the piezoelectric element 11, and when the liquid L such as physiological saline flows from the tip-side opening 121, the liquid L flows into the cavity H. Since the gas layer A is kept watertight, the liquid L does not flow into the gas layer A.
　圧電素子１１の外周面１１ｏの全周にわたって形成された気体層Ａに気体が充填されるため、気体層Ａは超音波を伝達しない領域として機能する。気体層Ａに充填された気体は液体Ｌと比較して超音波をほとんど伝達しないためである。
　なお、気体層Ａの径方向の寸法はわずかであっても、気体層Ａは超音波を伝達しない領域として機能する。呼吸振動時に圧電素子１１の外周面１１ｏと外筒１２の内周面１２ｉが接触しなければよい。気体層Ａの径方向の寸法が小さい方が超音波発振部１の細径化により好適である。 The gas layer A formed over the entire circumference of the outer peripheral surface 11o of the piezoelectric element 11 is filled with gas, so that the gas layer A functions as a region that does not transmit ultrasonic waves. This is because the gas filled in the gas layer A hardly transmits ultrasonic waves as compared with the liquid L.
Even if the radial dimension of the gas layer A is small, the gas layer A functions as a region that does not transmit ultrasonic waves. It is sufficient that the outer peripheral surface 11o of the piezoelectric element 11 and the inner peripheral surface 12i of the outer cylinder 12 do not come into contact with each other during breathing vibration. The smaller the radial dimension of the gas layer A is, the more suitable it is because the ultrasonic oscillating section 1 has a smaller diameter.
　図５は、空洞Ｈの一部が液体Ｌで満たされた超音波発振部１の断面図である。
　図５に示す超音波発振部１の空洞Ｈには、液体が流入する際に所定の量の気体が排出されずに残り、第二気体層Ａ２が空洞Ｈの内部に形成されている。第二気体層Ａ２は、液体Ｌの圧力により、基端側に配置される。液体Ｌと第二気体層Ａ２との境界は、超音波を反射する反射面Ｒとして機能する。反射面Ｒは超音波を先端側に反射させ、発生した超音波は破砕対象の結石Ｃに向けて発せられる。 FIG. 5 is a cross-sectional view of the ultrasonic wave oscillating unit 1 in which the cavity H is partially filled with the liquid L.
In the cavity H of the ultrasonic wave oscillating unit 1 shown in FIG. 5, a predetermined amount of gas remains without being discharged when the liquid flows in, and the second gas layer A2 is formed inside the cavity H. The second gas layer A2 is arranged on the base end side by the pressure of the liquid L. The boundary between the liquid L and the second gas layer A2 functions as a reflection surface R that reflects ultrasonic waves. The reflecting surface R reflects ultrasonic waves toward the tip side, and the generated ultrasonic waves are emitted toward the calculus C to be crushed.
［径方向共振現象］
　図６は、図４のように空洞Ｈの全体に充填された円柱状の液体ＬのＸＹ断面である。
　液体Ｌにおいて、中心軸Ｃからの距離ｒ、径方向の変位ｕ、波数ｋとすると、液体Ｌの径方向における共鳴振動の運動方程式は式１のように表される。
Figure JPOXMLDOC01-appb-M000001
 [Radial resonance phenomenon]
FIG. 6 is an XY cross section of the cylindrical liquid L filling the entire cavity H as shown in FIG.
In the liquid L, if the distance r from the central axis C, the radial displacement u, and the wave number k are used, the equation of motion of the resonant vibration in the radial direction of the liquid L is expressed by Equation 1.
Figure JPOXMLDOC01-appb-M000001
　式１は式２に展開され、式３が導かれる。式３において、Ｊ１は１次の第１種ベッセル関数（図７参照）であり、ｕ０は境界条件で決まる任意定数である。
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000003
 Expression 1 is expanded into Expression 2, and Expression 3 is derived. In Equation 3, J 1 is a first-order Bessel function of the first kind (see FIG. 7), and u 0 is an arbitrary constant determined by boundary conditions.
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000003
　変位ｕが極大となる距離（共振直径）のうち、最小の共振直径２ｒ０は、式４および式５にように算出される。
Figure JPOXMLDOC01-appb-M000004
Figure JPOXMLDOC01-appb-M000005
 The minimum resonance diameter 2r 0 of the distance (resonance diameter) at which the displacement u is maximized is calculated as in Expressions 4 and 5.
Figure JPOXMLDOC01-appb-M000004
Figure JPOXMLDOC01-appb-M000005
　図８は、圧電素子１１のＸＹ断面である。
　圧電素子１１において、中心軸Ｃからの距離ａ、径方向の変位ｕ、圧電素子１１の弾性定数Ｅ、圧電素子１１の音速ｋｓ、ポアソン比σ、密度ρ、時刻ｔとすると、圧電素子１１の径方向における共鳴振動の運動方程式は式６のように表される。ここで、圧電素子１１は厚みが非常に薄い円筒としてモデル化されている。
Figure JPOXMLDOC01-appb-M000006
 FIG. 8 is an XY cross section of the piezoelectric element 11.
In the piezoelectric element 11, when the distance a from the central axis C, the radial displacement u, the elastic constant E of the piezoelectric element 11, the sound velocity ks of the piezoelectric element 11, the Poisson's ratio σ, the density ρ, and the time t are given, The equation of motion of the resonance vibration in the radial direction is expressed by Equation 6. Here, the piezoelectric element 11 is modeled as a cylinder having a very thin thickness.
Figure JPOXMLDOC01-appb-M000006
　式６から式７が導かれる。
Figure JPOXMLDOC01-appb-M000007
 　式６において、Ｃｓは式８で表される。
Figure JPOXMLDOC01-appb-M000008
 Equation 6 is derived from Equation 6.
Figure JPOXMLDOC01-appb-M000007
 In Expression 6, Cs is represented by Expression 8.
Figure JPOXMLDOC01-appb-M000008
　式７から、圧電素子１１の共振直径２ａは式９で表される。
Figure JPOXMLDOC01-appb-M000009
 From Expression 7, the resonance diameter 2a of the piezoelectric element 11 is expressed by Expression 9.
Figure JPOXMLDOC01-appb-M000009
　ここで、液体Ｌが水であり、圧電素子１１がセラミックスで形成されているとすると、液体Ｌの共振直径２ｒ０と圧電素子１１の共振直径２ａとの比は、式１０のように表される。
Figure JPOXMLDOC01-appb-M000010
 Here, assuming that the liquid L is water and the piezoelectric element 11 is made of ceramics, the ratio between the resonance diameter 2r 0 of the liquid L and the resonance diameter 2a of the piezoelectric element 11 is expressed by Equation 10. It
Figure JPOXMLDOC01-appb-M000010
　式１０が示すように、セラミックスで薄く形成された圧電素子１１と、圧電素子１１の内径に等しい外径をもつ円柱状の液体Ｌとは共振する。すなわち、圧電素子１１の呼吸振動の共振周波数は、空洞Ｈ内の液体Ｌの径方向の共振周波数と同等である。ここで、圧電素子１１の呼吸振動の共振周波数が空洞Ｈ内の液体Ｌの径方向の共振周波数と同等とは、双方とも共振が発生する程度に略一致することである。 As shown in Expression 10, the piezoelectric element 11 formed thinly of ceramics and the cylindrical liquid L having an outer diameter equal to the inner diameter of the piezoelectric element 11 resonate. That is, the resonance frequency of the respiratory vibration of the piezoelectric element 11 is equal to the resonance frequency of the liquid L in the cavity H in the radial direction. Here, that the resonance frequency of the respiratory vibration of the piezoelectric element 11 is equivalent to the resonance frequency of the liquid L in the cavity H in the radial direction means that they both substantially coincide with each other to the extent that resonance occurs.
　圧電素子１１が超音波を発生させた際に、圧電素子１１と液体Ｌとに共振を発生させることで、印加電圧あたりの変位が大きい高効率超音波音源を実現できる。ここで圧電素子１１および円柱状の液体Ｌの長手方向の長さを、圧電素子１１の直径よりも充分に大きく選ぶことが望ましい。長手方向の長さが直径に近いと、長手方向と径方向の振動が連成してしまい、圧電素子１１の呼吸振動と液体Ｌの径方向の振動との共振現象が発生する条件を満たさなくなる。 By generating resonance between the piezoelectric element 11 and the liquid L when the piezoelectric element 11 generates ultrasonic waves, a highly efficient ultrasonic sound source with a large displacement per applied voltage can be realized. Here, it is desirable that the lengths of the piezoelectric element 11 and the cylindrical liquid L in the longitudinal direction be sufficiently larger than the diameter of the piezoelectric element 11. When the length in the longitudinal direction is close to the diameter, vibrations in the longitudinal direction and the radial direction are coupled to each other, and the condition for causing the resonance phenomenon between the respiratory vibration of the piezoelectric element 11 and the radial vibration of the liquid L cannot be satisfied. ..
［圧電素子１１のアスペクト比］
　次に、圧電素子１１の長手方向の長さと径方向の長さとの比（アスペクト比）と、超音波の音響出力と、の関係に関するシミュレーション結果を示す。ここで、圧電素子の径方向の長さとは、圧電素子の内径と外径との加算値を２で除算して算出される平均径のことである。シミュレーションに用いた圧電素子１１のモデルは二つである。一方のモデルは、「バッフル付き圧電素子１１Ａ」であり、他方のモデルは「外筒１２付き圧電素子１１」である。 [Aspect Ratio of Piezoelectric Element 11]
Next, simulation results regarding the relationship between the ratio of the length of the piezoelectric element 11 in the longitudinal direction to the length in the radial direction (aspect ratio) and the acoustic output of ultrasonic waves will be shown. Here, the radial length of the piezoelectric element is an average diameter calculated by dividing the sum of the inner diameter and the outer diameter of the piezoelectric element by 2. There are two models of the piezoelectric element 11 used in the simulation. One model is "piezoelectric element 11A with baffle", and the other model is "piezoelectric element 11 with outer cylinder 12".
　図９は、理想的なバッフル付き圧電素子１１Ａの断面図である。圧電素子１１Ａの外周には外筒１２が設けられていない。また、圧電素子１１Ａには、圧電素子１１Ａに対して負荷とならない理想的なバッフルが付いており、外筒１２がなくとも圧電素子１１Ａの外周に液体Ｌが流入せず、圧電素子１１Ａの外周面側に気体層Ａが形成されている。 FIG. 9 is a sectional view of an ideal baffled piezoelectric element 11A. The outer cylinder 12 is not provided on the outer circumference of the piezoelectric element 11A. Further, the piezoelectric element 11A is provided with an ideal baffle that does not become a load on the piezoelectric element 11A, and the liquid L does not flow into the outer periphery of the piezoelectric element 11A without the outer cylinder 12, and the outer periphery of the piezoelectric element 11A is A gas layer A is formed on the surface side.
　図１０は、外筒１２付き圧電素子１１の断面図である。
　圧電素子１１は外筒１２に保持されており、圧電素子１１の外周面１１ｏと外筒１２の内周面１２ｉとの間に、圧電素子１１の外周面１１ｏの全周にわたって、気体層Ａが形成される。 FIG. 10 is a sectional view of the piezoelectric element 11 with the outer cylinder 12.
The piezoelectric element 11 is held by the outer cylinder 12, and the gas layer A is formed between the outer peripheral surface 11o of the piezoelectric element 11 and the inner peripheral surface 12i of the outer cylinder 12 over the entire outer peripheral surface 11o of the piezoelectric element 11. It is formed.
　バッフル付き圧電素子１１Ａおよび外筒１２付き圧電素子１１において、圧電素子の厚みは圧電素子の内径の１／５とした。 In the piezoelectric element 11A with the baffle and the piezoelectric element 11 with the outer cylinder 12, the thickness of the piezoelectric element was set to 1/5 of the inner diameter of the piezoelectric element.
　図１１は、圧電素子のアスペクト比と音響出力との関係に関するシミュレーション結果である。図１１に示すように、外筒１２付き圧電素子１１は、圧電素子１１の平均径の長さに対する圧電素子１１の長手方向の長さの比が３．５付近において、バッフル付き圧電素子１１Ａよりも音響出力が高くなる。また、外筒１２付き圧電素子１１は、圧電素子１１の平均径の長さに対する圧電素子１１の長手方向の長さの比が３．５以上において、およそ一定の値となっている。 FIG. 11 is a simulation result regarding the relationship between the aspect ratio of the piezoelectric element and the acoustic output. As shown in FIG. 11, when the ratio of the length in the longitudinal direction of the piezoelectric element 11 to the length of the average diameter of the piezoelectric element 11 is around 3.5, the piezoelectric element 11 with the outer cylinder 12 is smaller than the piezoelectric element 11A with a baffle. Also has a higher sound output. The piezoelectric element 11 with the outer cylinder 12 has a substantially constant value when the ratio of the length in the longitudinal direction of the piezoelectric element 11 to the length of the average diameter of the piezoelectric element 11 is 3.5 or more.
［超音波処置具１００の動作］
　次に、超音波処置具１００の動作について説明する。
　術者は、尿道Ｕに内視鏡２００の内視鏡挿入部２０２を挿入し、膀胱Ｂの尿道口Ｏから尿管または腎臓Ｋまで内視鏡挿入部２０２の先端を挿入する。術者はモニタに表示された撮像部２０７が撮像した画像を確認しながら、内視鏡挿入部２０２の先端を破砕対象の結石Ｃに接近させる。 [Operation of ultrasonic treatment instrument 100]
Next, the operation of the ultrasonic treatment instrument 100 will be described.
The operator inserts the endoscope insertion portion 202 of the endoscope 200 into the urethra U, and inserts the tip of the endoscope insertion portion 202 from the urethral opening O of the bladder B to the ureter or the kidney K. The operator brings the tip of the endoscope insertion section 202 closer to the calculus C to be crushed while checking the image captured by the image capturing section 207 displayed on the monitor.
　術者は、超音波処置具１００の超音波発振部１を、図２に示すように、内視鏡挿入部２０２の先端の処置具チャネル開口２０３から突出させる。術者は、超音波発振部１の先端側開口１２１を、モニタに表示された画像を確認しながら、破砕対象の結石Ｃにさらに接近させる。 The operator causes the ultrasonic wave oscillating section 1 of the ultrasonic treatment instrument 100 to protrude from the treatment instrument channel opening 203 at the tip of the endoscope insertion section 202, as shown in FIG. The surgeon further brings the tip-side opening 121 of the ultrasonic wave oscillating unit 1 closer to the calculus C to be crushed, while checking the image displayed on the monitor.
　先端側開口１２１からは、処置具チャネル開口２０３から送水された生理食塩水が流入する。その結果、圧電素子１１の内周面１１ｉに囲まれた空洞Ｈは液体Ｌで充填される。一方、圧電素子１１の外周面１１ｏは依然として全周にわたって気体層Ａに囲まれている。術者は、空洞Ｈに所定の量の気体を残存させて、第二気体層Ａ２を形成してもよい。 The physiological saline sent from the treatment instrument channel opening 203 flows in from the distal end side opening 121. As a result, the cavity H surrounded by the inner peripheral surface 11i of the piezoelectric element 11 is filled with the liquid L. On the other hand, the outer peripheral surface 11o of the piezoelectric element 11 is still surrounded by the gas layer A over the entire circumference. The operator may leave a predetermined amount of gas in the cavity H to form the second gas layer A2.
　術者は、駆動部３に設けられたスイッチ等を操作して、圧電素子１１へ電圧を印加する。その結果、圧電素子１１は、圧電効果により径方向に呼吸振動して超音波を発生させる。発生した超音波は、空洞Ｈの内部に充填された液体Ｌを介して先端側開口１２１から先端側に発せされる。 The surgeon operates a switch or the like provided on the drive unit 3 to apply a voltage to the piezoelectric element 11. As a result, the piezoelectric element 11 breathes and vibrates in the radial direction by the piezoelectric effect to generate ultrasonic waves. The generated ultrasonic waves are emitted to the tip side from the tip side opening 121 via the liquid L filled in the cavity H.
　圧電素子１１の外周面１１ｏは全周にわたって気体層Ａに囲まれているため、超音波が伝わりにくい。そのため発生した超音波のほとんどは、先端側開口１２１から先端側に発せされる。そのため、発生した超音波を、破砕対象の結石Ｃに向けてロスなく発することができる。 Since the outer peripheral surface 11o of the piezoelectric element 11 is surrounded by the gas layer A over the entire circumference, it is difficult for ultrasonic waves to propagate. Therefore, most of the generated ultrasonic waves are emitted to the tip side from the tip side opening 121. Therefore, the generated ultrasonic waves can be emitted toward the calculus C to be crushed without loss.
　本実施形態の超音波処置具１００によれば、圧電素子１１の外周面１１ｏは全周にわたって気体層Ａに囲まれているため、超音波が伝わりにくい。そのため発生した超音波のほとんどは、先端側開口１２１から先端側に発せされる。そのため、発生した超音波を、破砕対象の結石Ｃに向けてロスなく発することができる。 According to the ultrasonic treatment device 100 of this embodiment, since the outer peripheral surface 11o of the piezoelectric element 11 is surrounded by the gas layer A over the entire circumference, it is difficult for ultrasonic waves to propagate. Therefore, most of the generated ultrasonic waves are emitted to the tip side from the tip side opening 121. Therefore, the generated ultrasonic waves can be emitted toward the calculus C to be crushed without loss.
　本実施形態の超音波処置具１００によれば、圧電素子１１の内部に第二気体層Ａ２が形成された場合、反射面Ｒによって超音波を先端側に反射させて、好適に超音波を結石Ｃに伝達させることができる。 According to the ultrasonic treatment device 100 of the present embodiment, when the second gas layer A2 is formed inside the piezoelectric element 11, the reflecting surface R reflects the ultrasonic wave toward the tip side, and the ultrasonic wave is preferably stoned. Can be transmitted to C.
　本実施形態の超音波処置具１００によれば、圧電素子１１は筒形状であり細径化してもインピーダンスが低く、低い駆動電圧で高出力な超音波を得やすい。また、圧電素子１１の外周面１１ｏに形成する気体層Ａは、薄く形成された場合であっても、超音波を伝達させない機能を発揮する。そのため、圧電素子１１の外周面１１ｏに気体層Ａを形成した場合であっても、超音波発振部１を好適に細径化することができる。 According to the ultrasonic treatment device 100 of the present embodiment, the piezoelectric element 11 has a tubular shape and has a low impedance even when the diameter is reduced, and it is easy to obtain a high output ultrasonic wave with a low driving voltage. Further, the gas layer A formed on the outer peripheral surface 11o of the piezoelectric element 11 exhibits a function of not transmitting ultrasonic waves even when formed thin. Therefore, even when the gas layer A is formed on the outer peripheral surface 11o of the piezoelectric element 11, the ultrasonic wave oscillating portion 1 can be suitably thinned.
　以上、本発明の一実施形態について図面を参照して詳述したが、具体的な構成はこの実施形態に限られるものではなく、本発明の要旨を逸脱しない範囲の設計変更等も含まれる。また、上述の実施形態および変形例において示した構成要素は適宜に組み合わせて構成することが可能である。 As described above, one embodiment of the present invention has been described in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and includes design changes and the like without departing from the spirit of the present invention. Further, the constituent elements shown in the above-described embodiments and modifications can be appropriately combined and configured.
（変形例１）
　例えば、上記実施形態において、圧電素子１１はセラミックによって形成されていたが、本発明に係る圧電素子はこれに限定されない。本発明に係る圧電素子は、セラミック以外の受動素子、例えば圧電単結晶によって形成されていてもよい。 (Modification 1)
For example, in the above embodiment, the piezoelectric element 11 is made of ceramic, but the piezoelectric element according to the present invention is not limited to this. The piezoelectric element according to the present invention may be formed of a passive element other than ceramic, for example, a piezoelectric single crystal.
（変形例２）
　例えば、上記実施形態において、圧電素子１１および外筒１２は円筒形状に形成されていたが、本発明に係る圧電素子および外筒はこれに限定されない。本発明に係る圧電素子および外筒は、例えば角筒形状に形成されていてもよい。 (Modification 2)
For example, in the above embodiment, the piezoelectric element 11 and the outer cylinder 12 are formed in a cylindrical shape, but the piezoelectric element and the outer cylinder according to the present invention are not limited to this. The piezoelectric element and the outer cylinder according to the present invention may be formed in a rectangular tube shape, for example.
　以下、本発明を実施例に基づいて詳細に説明するが、本発明の技術範囲はこれらの実施例に限定されるものではない。 Hereinafter, the present invention will be described in detail based on examples, but the technical scope of the present invention is not limited to these examples.
＜実施例１＞
　図１２は、実施例１の圧電素子１１の模式図である。
　実施例１は、長手方向の長さが３ｍｍ、内径の長さが０．８ｍｍ、外径の長さが１．０ｍｍの圧電素子１１である。実施例１の圧電素子１１は外周が全て空気層Ａに接している。また、空洞Ｈは全て液体Ｌで満たされている。 <Example 1>
FIG. 12 is a schematic diagram of the piezoelectric element 11 according to the first embodiment.
Example 1 is a piezoelectric element 11 having a longitudinal length of 3 mm, an inner diameter of 0.8 mm, and an outer diameter of 1.0 mm. The outer periphery of the piezoelectric element 11 of Example 1 is in contact with the air layer A. Further, the cavity H is completely filled with the liquid L.
＜実施例２＞
　図１３は、実施例２の圧電素子１１の模式図である。
　実施例２は、長手方向の長さが３ｍｍ、内径の長さが０．８ｍｍ、外径の長さが１．０ｍｍの圧電素子１１である。実施例２の圧電素子１１は外周が全て空気層Ａに接している。また、空洞Ｈは半分が液体Ｌで満たされており、基端側半分に第二気体層Ａ２が形成されている。液体Ｌと第二気体層Ａ２との境界には反射面Ｒが形成されている。 <Example 2>
FIG. 13 is a schematic diagram of the piezoelectric element 11 according to the second embodiment.
Example 2 is a piezoelectric element 11 having a longitudinal length of 3 mm, an inner diameter of 0.8 mm, and an outer diameter of 1.0 mm. The outer periphery of the piezoelectric element 11 of Example 2 is in contact with the air layer A. Further, half of the cavity H is filled with the liquid L, and the second gas layer A2 is formed in the half on the base end side. A reflective surface R is formed at the boundary between the liquid L and the second gas layer A2.
＜実施例３＞
　図１４は、実施例３の圧電素子１１の模式図である。
　実施例１は、長手方向の長さが１．５ｍｍ、内径の長さが０．８ｍｍ、外径の長さが１．０ｍｍの圧電素子１１である。実施例１の圧電素子１１は外周が全て空気層Ａに接している。また、空洞Ｈは全て液体Ｌで満たされている。 <Example 3>
FIG. 14 is a schematic diagram of the piezoelectric element 11 according to the third embodiment.
Example 1 is a piezoelectric element 11 having a longitudinal length of 1.5 mm, an inner diameter of 0.8 mm, and an outer diameter of 1.0 mm. The outer periphery of the piezoelectric element 11 of Example 1 is in contact with the air layer A. Further, the cavity H is completely filled with the liquid L.
　実施例１－３を用いて音響出力を算出するシミュレーションを行った。シミュレーションにおいて、液体Ｌは水であり、圧電素子１１はセラミックスで形成されているものとした。圧電素子１１の駆動電圧は１Ｖとした。いずれの実施例においても、Ｚ軸は圧電素子１１の先端側開口が位置する部分を原点と定義した。 A simulation for calculating the acoustic output was performed using Examples 1-3. In the simulation, the liquid L is water and the piezoelectric element 11 is made of ceramics. The drive voltage of the piezoelectric element 11 was set to 1V. In any of the examples, the Z-axis was defined as the origin where the tip side opening of the piezoelectric element 11 was located.
　図１５は、圧電素子１１の中心軸Ｃにおける音圧分布を比較したグラフである。図１６は、音圧の最大値を１として正規化したグラフである。
　音圧の最大値は、図１５に示すように、実施例１が最も大きく、実施例３が最も小さい。いずれの実施例においては、液体Ｌが位置する領域の中心付近が最も音圧が大きくなっている。 FIG. 15 is a graph comparing the sound pressure distributions on the central axis C of the piezoelectric element 11. FIG. 16 is a graph in which the maximum value of sound pressure is normalized to 1.
As shown in FIG. 15, the maximum value of the sound pressure is highest in Example 1 and lowest in Example 3. In any of the examples, the sound pressure is highest near the center of the region where the liquid L is located.
　実施例２は、実施例１と比較して、共振抵抗が大きくなるため、先端側開口での音圧の絶対値は下がっている。しかしながら、先端側開口と音圧最大部分との音圧差は小さい。
　実施例２は、実施例３と比較して、先端側開口と音圧最大部分との音圧差は略同一であるが、先端側開口での音圧の絶対値は高い。 Since the resonance resistance of the second embodiment is larger than that of the first embodiment, the absolute value of the sound pressure at the tip side opening is lowered. However, the sound pressure difference between the tip side opening and the sound pressure maximum portion is small.
In Example 2, as compared with Example 3, the sound pressure difference between the tip side opening and the sound pressure maximum portion is substantially the same, but the absolute value of the sound pressure at the tip side opening is high.
　先端側開口での音圧の絶対値が高い場合、破砕対象の結石Ｃに対して、超音波を高出力で発することができる。しかしながら、先端側開口と音圧最大部分との音圧差が大きい場合、音圧最大部分に先端側開口より高い音圧を発生させる必要があり、圧電素子１１に高い負荷がかかることとなる。そのため、実施例１や実施例３と比較して、実施例２の圧電素子１１が、先端側開口での音圧および先端側開口と中心部分との音圧差の観点から、バランスのよい構成と考察される。 If the absolute value of the sound pressure at the tip side opening is high, ultrasonic waves can be emitted with high output to the calculus C to be crushed. However, when the sound pressure difference between the tip-side opening and the sound pressure maximum portion is large, it is necessary to generate a sound pressure higher than the tip-side opening at the sound pressure maximum portion, and a high load is applied to the piezoelectric element 11. Therefore, as compared with the first and third embodiments, the piezoelectric element 11 according to the second embodiment has a well-balanced configuration in terms of sound pressure at the tip-side opening and sound pressure difference between the tip-side opening and the central portion. Be considered.
　本発明は、湾曲部を有する医療用マニピュレータに適用することができる。 The present invention can be applied to a medical manipulator having a curved portion.
３００　結石破砕システム
２００　内視鏡
１００　超音波処置具
１　　　超音波発振部
１１　　圧電素子
１１Ａ　圧電素子
１１ｄ　先端部
１１ｉ　内周面
１１ｏ　外周面
１２　　外筒
１２ｄ　先端部
１２ｉ　内周面
１２ｓ　筒部
１２１　先端側開口
１２２　基端側開口
２　　　挿入部
２１　　第一導電線
２２　　第二導電線
３　　　駆動部
Ｈ　　　空洞
Ｒ　　　反射面
Ａ　　　気体層
Ａ２　　第二気体層 300 Calculus crushing system 200 Endoscope 100 Ultrasonic treatment tool 1 Ultrasonic wave oscillating unit 11 Piezoelectric element 11A Piezoelectric element 11d Piezoelectric element 11d Tip part 11i Inner peripheral surface 11o Outer surface 12d Outer tube 12d Tip part 12i Inner peripheral surface 12s Tube part 121 Tip side Opening 122 Base end side opening 2 Insertion portion 21 First conductive wire 22 Second conductive wire 3 Driving portion H Cavity R Reflecting surface A Gas layer A2 Second gas layer

Claims (5)

  1. 　超音波を伝搬させる液体が充填される空洞を内部に有する筒形状であり、分極方向が内周面と外周面とを結ぶ厚み方向である圧電素子と、
    　前記圧電素子の外周面側に気体層を設けて前記圧電素子を保持する外筒と、
    　を備える、
    　超音波処置具。     A piezoelectric element having a cylindrical shape having a cavity filled with a liquid that propagates ultrasonic waves inside, and a polarization direction being a thickness direction connecting an inner peripheral surface and an outer peripheral surface,
    An outer cylinder for holding the piezoelectric element by providing a gas layer on the outer peripheral surface side of the piezoelectric element,
    With
    Ultrasonic treatment tool.
  2. 　前記圧電素子の呼吸振動の共振周波数は、空洞内の液体の半径方向の共振周波数と同等である
    　請求項１に記載の超音波処置具。     The ultrasonic treatment instrument according to claim 1, wherein the resonance frequency of the respiratory vibration of the piezoelectric element is equal to the resonance frequency of the liquid in the cavity in the radial direction.
  3. 　前記圧電素子の内径に対する前記圧電素子の長手方向の長さの比は、３．５以上である、
    　請求項２に記載の超音波処置具。     The ratio of the length in the longitudinal direction of the piezoelectric element to the inner diameter of the piezoelectric element is 3.5 or more,
    The ultrasonic treatment device according to claim 2.
  4. 　前記圧電素子の超音波の照射方向を先端側、前記先端側と長手方向に対向する方向を基端側とし、
    　前記圧電素子の前記空洞は、前記液体が充填された状態において、前記長手方向の長さを２分割した分割位置よりも基端側に超音波を反射する反射面となる第二気体層が形成される、
    　請求項１に記載の超音波処置具。     The ultrasonic wave irradiation direction of the piezoelectric element is the distal end side, and the direction opposite to the distal end side in the longitudinal direction is the proximal end side,
    In the cavity filled with the liquid, a second gas layer is formed in the cavity of the piezoelectric element, which serves as a reflection surface for reflecting ultrasonic waves toward a base end side of a division position where the length in the longitudinal direction is divided into two. Will be
    The ultrasonic treatment device according to claim 1.
  5. 　前記分割位置は、前記長手方向の長さを２等分割した位置である、
    　請求項４に記載の超音波処置具。     The division position is a position obtained by dividing the length in the longitudinal direction into two equal parts.
    The ultrasonic treatment device according to claim 4.
PCT/JP2019/007064 2019-02-25 2019-02-25 Ultrasound treatment tool WO2020174532A1 (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5220412B2 (en) * 1974-11-20 1977-06-03
JPH06217989A (en) * 1993-01-29 1994-08-09 Olympus Optical Co Ltd Thermotherapy device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5220412B2 (en) * 1974-11-20 1977-06-03
JPH06217989A (en) * 1993-01-29 1994-08-09 Olympus Optical Co Ltd Thermotherapy device

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