JP2015208711A - Ultrasonic vibrator and ultrasonic medical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic vibrator which is compact and excellent in vibration transmission efficiency and an ultrasonic medical device.SOLUTION: An ultrasonic vibrator 1 comprises two metal blocks 2, a plurality of piezoelectric elements 4 laminated between the metal blocks 2, and a joint material 5 joining the metal blocks 2 and the piezoelectric elements 4, and the piezoelectric elements each other. On a cross section in parallel to the joint surface between the metal block 2 and the piezoelectric element 4, the metal blocks 2 and the piezoelectric elements 4 are rectangular.

Description

  The present invention relates to an ultrasonic transducer and an ultrasonic medical device that excite ultrasonic waves.

  As an ultrasonic vibrator, there is an ultrasonic vibrator called a Langevin vibrator in which a piezoelectric vibrator such as a piezoelectric ceramic is sandwiched and fixed from both sides by a metal block. The Langevin vibrator is an element that can generate an efficient ultrasonic vibration by vibrating the whole element at the whole natural frequency using the resonance phenomenon of the metal block. In general, an ultrasonic transducer has a structure in which the bonding between a piezoelectric transducer and a metal block is fixed with an adhesive or tightened with a bolt (see Patent Document 1).

  FIG. 13 is a diagram showing a conventional ultrasonic transducer 1. FIG. 14 shows a cross section of the piezoelectric element unit 3 and the wiring 7 when the conventional ultrasonic transducer 1 is disposed in the case 6.

  In the conventional example shown in FIG. 13, two metal blocks 2, a plurality of piezoelectric elements 4 stacked between the metal blocks 2, a metal block 2, the piezoelectric elements 4, and a bonding material 5 that joins the piezoelectric elements 4 together. . As shown in FIG. 13, the metal block 2, the piezoelectric element 4, and the piezoelectric elements 4 are bonded to each other by a bonding material 5. The cross section parallel to the joint surface between the metal block 2 and the piezoelectric element 4 is circular.

  As shown in FIG. 14, the conventional ultrasonic transducer 1 is provided with a piezoelectric element unit 3 and a wiring 7 connected to the piezoelectric element 4 in a case 6. The wiring 7 is disposed adjacent to the piezoelectric element 4 in the case 6 in order to connect every other piezoelectric element 4.

JP 2010-89007 A

  However, in the ultrasonic transducer 1 as shown in FIG. 13 and FIG. 14, the wiring 7 is disposed in the case 6, so that the cross section of the piezoelectric element 4 becomes small, and the vibration transmission efficiency becomes small.

  An embodiment according to the present invention is to provide an ultrasonic transducer and an ultrasonic medical device that are compact and have good vibration transmission efficiency.

  An ultrasonic transducer according to an aspect of the present invention includes two metal blocks, a plurality of piezoelectric elements stacked between the metal blocks, and a joint that joins the metal block to the piezoelectric element and the piezoelectric elements. The metal block and the piezoelectric element are rectangular in a cross section parallel to the joint surface between the metal block and the piezoelectric element.

  An ultrasonic medical device according to an aspect of the present invention includes the ultrasonic transducer, and a probe tip portion that transmits ultrasonic vibration generated by the ultrasonic transducer and treats living tissue. And

  According to the embodiment of the present invention, it is possible to provide an ultrasonic transducer and an ultrasonic medical device that are compact and have good vibration transmission efficiency.

The ultrasonic transducer | vibrator before joining of 1st Embodiment is shown. The ultrasonic transducer | vibrator after joining of 1st Embodiment is shown. The cross section of a piezoelectric element unit and wiring at the time of arrange | positioning the ultrasonic transducer | vibrator of 1st Embodiment in a case is shown. The definition of the dimension of the ultrasonic transducer | vibrator of 1st Embodiment is shown. It is a graph which shows the curvature amount of the piezoelectric element of 1st Embodiment. It is a graph which shows the relationship of the dimension at the time of making the curvature amount of the x direction of the piezoelectric element of 1st Embodiment, and a y direction equivalent. It is a graph which shows the relationship of FIG. 6 by the ratio of each dimension. The ultrasonic transducer | vibrator after joining of 2nd Embodiment is shown. The piezoelectric element unit at the time of arrange | positioning the ultrasonic transducer | vibrator of 2nd Embodiment in a case, and the cross section of wiring are shown. 1 shows an overall configuration of an ultrasonic medical apparatus according to the present embodiment. 1 shows an overall schematic configuration of a transducer unit of an ultrasonic medical apparatus according to the present embodiment. The whole structure of the ultrasonic medical device of the other aspect of the ultrasonic medical device which concerns on this embodiment is shown. It is a figure which shows the conventional ultrasonic transducer | vibrator. The cross section of a piezoelectric element unit and wiring at the time of arrange | positioning the conventional ultrasonic transducer | vibrator in a case is shown.

  Hereinafter, the ultrasonic transducer 1 of the present embodiment will be described.

  FIG. 1 shows an ultrasonic transducer 1 before bonding according to the first embodiment. FIG. 2 shows the ultrasonic transducer 1 after bonding according to the first embodiment.

  As shown in FIG. 1, the ultrasonic transducer 1 according to the first embodiment includes two metal blocks 2, a plurality of piezoelectric element units 3 stacked between the metal blocks 2, a metal block 2, and a piezoelectric element 4. And a bonding material 5 for bonding the piezoelectric elements 4 to each other. As shown in FIG. 2, the metal block 2, the piezoelectric element 4, and the piezoelectric elements 4 are bonded to each other by a bonding material 5.

  FIG. 3 shows a cross section of the piezoelectric element unit 3 and the wiring 7 when the ultrasonic transducer 1 of the first embodiment is disposed in the case 6.

  In the ultrasonic transducer 1 of the first embodiment, the cross section of the metal block 2 and the piezoelectric element 4 is rectangular. And it is preferable to arrange | position in the case 6 so that the long side of the metal block 2 with a rectangular cross section and the piezoelectric element 4 may adjoin the wiring 7. FIG.

  By arranging in this way, the space in the case 6 can be used effectively, and it is possible to provide a compact ultrasonic transducer and ultrasonic medical device that are compact and have good vibration transmission efficiency.

  Here, each material of the ultrasonic transducer | vibrator 1 of this embodiment is demonstrated.

  The piezoelectric element 4 is preferably made of single crystal lithium niobate having a high Curie point. For example, it is preferable to use a lithium niobate wafer having a crystal orientation called 36-degree rotation Y-cut so that the electromechanical coupling coefficient in the thickness direction of the piezoelectric element 4 is increased, and wettability between lithium niobate and non-lead solder In order to improve the adhesion, a base metal such as Ti / Pt or Cr / Ni / Au is formed on the front and back surfaces of the lithium niobate wafer and then cut into a rectangle by dicing or the like.

  As the bonding material 5, a lead-free solder having a melting point lower than the Curie point, preferably not more than half of the Curie point is used. However, when solder is used as the bonding material and the solder supply method is solder pellets, it is difficult to bond the uneven portions without bubbles. Therefore, it is preferable that the joint portion between the piezoelectric element 4 and the metal block 2 is a flat surface.

  The metal block 2 is made of aluminum alloy such as duralumin, titanium alloy, pure titanium, stainless steel, mild steel, nickel chrome steel, tool steel, brass, monel metal or the like.

In the ultrasonic transducer 1 of the present embodiment, as an example, 64 titanium alloy (64Ti) is used for the metal block 2, and 36Y lithium niobate (LiNb03) having a crystal orientation called 36-degree rotation Y cut is used as the piezoelectric element 4. As shown in Table 1, 64 titanium alloy has an isotropic thermal expansion coefficient, while 36Y lithium niobate is an anisotropic material having different thermal expansion coefficients in the plane. Note that x and y indicate in-plane orthogonal directions.

  Therefore, for example, anisotropy occurs in the residual stress when the rectangular metal block 2 having the same cross-sectional aspect ratio and the piezoelectric element 4 are joined, resulting in different states in the vertical and horizontal directions. For this reason, there is a possibility that the piezoelectric element 4 is easily cracked when driven at a high amplitude.

  Therefore, in this embodiment, by setting the aspect ratio of the joint surface between the metal block 2 and the piezoelectric element 4 in accordance with the thermal expansion coefficient of the piezoelectric element 4, the residual when the metal block 2 and the piezoelectric element 4 are joined is set. Relieve stress. For example, in the x direction and the y direction perpendicular to each other in the joint surface between the metal block 2 and the piezoelectric element 4, the side with the larger difference in thermal expansion coefficient is shortened and the side with the smaller side is lengthened.

  By adopting such a configuration, in the x direction and the y direction perpendicular to each other in the joint surface between the metal block 2 and the piezoelectric element 4, it becomes easy to be deformed in a direction having a large difference in thermal expansion coefficient, and the amount of thermal warpage is made equal. Thus, the residual stress when the metal block 2 and the piezoelectric element 4 are joined can be made uniform. In addition, it is possible to provide an ultrasonic transducer and an ultrasonic medical device in which damage to the piezoelectric element 4 is suppressed and vibration transmission efficiency is good.

  FIG. 4 shows the definition of the dimensions of the ultrasonic transducer 1 of the first embodiment. FIG. 5 is a graph showing the amount of warpage of the piezoelectric element 4 of the present embodiment. FIG. 6 is a graph showing the relationship of dimensions when the amounts of warpage in the x direction and y direction of the piezoelectric element 4 of the first embodiment are made equal. FIG. 7 is a graph showing the relationship of FIG.

  In the first embodiment, 64 titanium alloy and 36Y lithium niobate having thermal expansion coefficients shown in Table 1 are used for the metal block 2 and the piezoelectric element 4, respectively. Here, the dimension h1 in the z direction of the metal block 2 shown in FIG. 4 is 20 mm, the dimension in the x direction of the joint surface between the metal block 2 and the piezoelectric element 4 is A = the dimension L in the y direction is 10 mm (square), and the temperature change FIG. 5 shows the relationship between the half h2 of the dimension in the z direction of the piezoelectric element unit 3 at 300 ° C. and the warpage amount δ. However, the warpage amount δ is a difference in the position of the center portion in the z direction with respect to the end portion.

  A piezoelectric element unit for making the dimension A in the x direction of the piezoelectric element 4 constant and making the warpage amount δ in the x direction and the y direction of the piezoelectric element 4 at the joint surface of the metal block 2 and the piezoelectric element 4 equal. The relationship between the half h2 of the dimension 3 in the z direction and the dimension L in the y direction of the piezoelectric element 4 can be expressed as shown in FIG. If the relationship of FIG. 6 is shown by the ratio of each dimension, it can be expressed as shown in FIG.

  As shown in FIG. 7, for example, in the case of h1 <h2, when the L / A ratio is 0.6 ≦ L / A ≦ 0.8, preferably L / A = 0.7, the x direction and the y direction It is possible to make the warpage amount δ equal. Further, in the case of h1 = h2, when the L / A ratio is 0.4 ≦ L / A ≦ 0.6, preferably L / A = 0.5, the warpage amount δ in the x direction and the y direction is made equal. It becomes possible. Further, in the case of h1> h2, when the L / A ratio is 0.8 ≦ L / A ≦ 2.5, preferably 0.9 ≦ L / A ≦ 1.5, the amount of warpage in the x and y directions It is possible to make δ equal. These numerical values are obtained by approximating the numerical values that can be read from FIG. 7 to the first decimal place.

  By adopting such a structure, it is possible to equalize the stress applied to the piezoelectric element 4 by reducing the bias depending on the location, and it is possible to suppress damage to the piezoelectric element 4 and to provide ultrasonic vibration with good vibration transmission efficiency. A child and an ultrasonic medical device can be provided.

  FIG. 8 shows an ultrasonic transducer 1 according to the second embodiment. FIG. 9 shows a cross section of the piezoelectric element unit 3 and the wiring 7 when the ultrasonic transducer 1 of the second embodiment is disposed in the case 6.

  In the ultrasonic transducer 1 of the second embodiment, the cross section of the metal block 2 and the piezoelectric element 4 is elliptical. And it is preferable to arrange | position the wiring 7 in the case 6 so that the elliptical long side of the cross section of the metal block 2 and the piezoelectric element 4 may be pinched | interposed.

  By arranging in this way, the space in the case 6 can be used effectively, and it is possible to provide a compact ultrasonic transducer and ultrasonic medical device that are compact and have good vibration transmission efficiency.

  FIG. 10 shows an overall configuration of the ultrasonic medical apparatus according to the present embodiment. FIG. 11 shows an overall schematic configuration of the transducer unit of the ultrasonic medical apparatus according to the present embodiment.

  An ultrasonic medical device 101 shown in FIG. 10 includes a vibrator unit 103 having an ultrasonic vibrator 1 that mainly generates ultrasonic vibrations, and a handle unit 104 that treats the affected area using the ultrasonic vibrations. Is provided.

  The handle unit 104 includes an operation unit 105, an insertion sheath unit 108 including a long mantle tube 107, and a distal treatment unit 30. The proximal end portion of the insertion sheath portion 108 is attached to the operation portion 105 so as to be rotatable about the axis. The distal treatment section 30 is provided at the distal end of the insertion sheath section 108. The operation unit 105 of the handle unit 104 includes an operation unit main body 109, a fixed handle 10, a movable handle 11, and a rotary knob 12. The operation unit body 109 is formed integrally with the fixed handle 10.

  A slit 13 through which the movable handle 11 is inserted is formed on the back side of the connecting portion between the operation unit main body 109 and the fixed handle 10. The upper part of the movable handle 11 extends through the slit 13 into the operation unit main body 109. A handle stopper 14 is fixed to the lower end of the slit 13. The movable handle 11 is rotatably attached to the operation unit main body 109 via the handle support shaft 15. The movable handle 11 is opened and closed with respect to the fixed handle 10 as the movable handle 11 rotates about the handle support shaft 15.

  A substantially U-shaped connecting arm 16 is provided at the upper end of the movable handle 11. The insertion sheath portion 108 includes a mantle tube 107 and an operation pipe 17 that is inserted into the mantle tube 107 so as to be movable in the axial direction. A large diameter portion 18 having a diameter larger than that of the distal end portion is formed at the proximal end portion of the outer tube 107. The rotary knob 12 is mounted around the large diameter portion 18.

  A ring-shaped slider 20 is provided on the outer peripheral surface of the operation pipe 19 so as to be movable along the axial direction. A fixing ring 22 is disposed behind the slider 20 via a coil spring (elastic member) 21.

  Further, the proximal end portion of the grip portion 23 is rotatably connected to the distal end portion of the operation pipe 19 via an action pin. This gripping part 23 constitutes a treatment part of the ultrasonic medical apparatus 1 together with the distal end part 31 of the probe 106. When the operation pipe 19 moves in the axial direction, the grip portion 23 is pushed and pulled in the front-rear direction via the action pin. At this time, when the operation pipe 19 is moved to the hand side, the grip portion 23 is rotated clockwise about the fulcrum pin via the action pin. As a result, the gripping portion 23 rotates in the direction approaching the distal end portion 31 of the probe 106 (the closing direction). At this time, the living tissue can be grasped between the single-opening type grasping portion 23 and the distal end portion 31 of the probe 106.

  In this state where the living tissue is gripped, power is supplied from the ultrasonic power source to the ultrasonic vibrator 1 to vibrate the ultrasonic vibrator 1. This ultrasonic vibration is transmitted to the distal end portion 31 of the probe 106. The ultrasonic tissue is used to treat the biological tissue gripped between the grip portion 23 and the tip portion 31 of the probe 106.

  Here, the vibrator unit 103 will be described. As shown in FIG. 11, the vibrator unit 103 integrally assembles the ultrasonic vibrator 1 and a probe 106 that is a rod-like vibration transmission member that transmits ultrasonic vibration generated by the ultrasonic vibrator 1. It is a thing.

  The ultrasonic transducer 102 is connected to a horn 32 that amplifies the amplitude of the ultrasonic transducer. The horn 32 is made of duralumin, stainless steel, or a titanium alloy such as 64Ti (Ti-6Al-4V). The horn 32 is formed in a conical shape whose outer diameter becomes narrower toward the distal end side, and an outward flange 33 is formed on the base end outer peripheral portion. Here, the shape of the horn 32 is not limited to the conical shape, but may be an exponential shape in which the outer diameter decreases exponentially toward the tip side, or a step shape that gradually decreases toward the tip side. May be. A front mass 39 is integrally formed behind the outward flange 33.

  The probe 106 includes a probe main body 34 formed of a titanium alloy such as 64Ti (Ti-6Al-4V). On the proximal end side of the probe main body 34, the ultrasonic transducer 1 connected to the horn 32 is disposed. In this way, the transducer unit 3 in which the probe 106 and the ultrasonic transducer 2 are integrated is formed. In the probe 106, the probe main body 34 and the horn 32 are screwed together, and the probe main body 34 and the horn 32 are joined.

  The ultrasonic vibration generated by the ultrasonic transducer 1 is amplified by the horn 32 and then transmitted to the distal end portion 31 side of the probe 106. The distal end portion 31 of the probe 106 is formed with a treatment portion to be described later for treating a living tissue.

  In addition, two rubber linings 35 are attached to the outer peripheral surface of the probe main body 34 at intervals of vibration node positions in the middle of the axial direction at intervals formed in a ring shape with an elastic member. These rubber linings 35 prevent contact between the outer peripheral surface of the probe main body 34 and an operation pipe 19 described later. That is, when assembling the insertion sheath portion 108, the probe 106 as a transducer-integrated probe is inserted into the operation pipe 19. At this time, the rubber lining 35 prevents contact between the outer peripheral surface of the probe main body 34 and the operation pipe 19.

  The ultrasonic vibrator 1 is electrically connected via an electric cable 36 to a power supply device main body (not shown) that supplies a current for generating ultrasonic vibration. The ultrasonic vibrator 1 is driven by supplying power from the power supply device main body to the ultrasonic vibrator 1 through the wiring in the electric cable 36. The vibrator unit 103 includes an ultrasonic vibrator 1 that generates ultrasonic vibrations, a horn 32 that amplifies the generated ultrasonic vibrations, and a probe 106 that transmits the amplified ultrasonic vibrations.

  FIG. 12 shows an overall configuration of an ultrasonic medical apparatus according to another aspect of the ultrasonic medical apparatus according to the present embodiment.

  The ultrasonic transducer 1 and the transducer unit 103 do not necessarily have to be stored in the operation unit main body 109 as shown in FIG. 10, for example, are stored in the operation pipe 19 as shown in FIG. May be. In the ultrasonic medical device 101 of FIG. 10, the electric cable 36 between the bending stop 52 of the ultrasonic transducer 1 and the connector 38 disposed at the base of the operation unit main body 109 is inserted into the metal pipe 37. Has been stored. Here, the connector 38 is not essential, and the electric cable 36 may be extended to the inside of the operation unit main body 109 and directly connected to the folding stop 52 of the ultrasonic transducer 1. The ultrasonic medical apparatus 101 can further improve the space saving in the operation unit main body 109 with the configuration shown in FIG. The functions of the ultrasonic medical apparatus 101 in FIG. 12 are the same as those in FIG.

  As described above, the ultrasonic transducer 1 according to this embodiment includes two metal blocks 2, a plurality of piezoelectric elements 4 stacked between the metal blocks 2, the metal blocks 2, the piezoelectric elements 4, and the piezoelectric elements 4. And the metal block 2 and the piezoelectric element 4 are rectangular in a cross section parallel to the joint surface between the metal block 2 and the piezoelectric element 4, and are compact and have good vibration transmission efficiency. It becomes possible.

  Further, in the ultrasonic transducer 1 according to this embodiment, the piezoelectric element 4 is formed so that the thermal expansion coefficient is different between the long side direction and the short side direction of the rectangle, and the long side and the short side of the rectangle are Is determined in accordance with the amount of thermal warping caused by the difference in thermal expansion coefficient between the metal block 2 and the piezoelectric element 4. Thereby, since there is no difference in deformation according to the difference in thermal expansion coefficient, the amount of thermal warpage can be made equal, and the residual stress when the metal block 2 and the piezoelectric element 4 are joined is made equal. Is possible.

In the ultrasonic transducer 1 according to this embodiment, the metal block 2 is made of 64 titanium alloy (64Ti), and the piezoelectric element 4 is made of lithium niobate (LiNb03) having a 36-degree rotated Y-cut crystal orientation. The length of the short side of the metal block 2 and the piezoelectric element 4 is A, the length of the long side is L, the length of the metal block 2 in the direction orthogonal to the bonding surface is h1, and the length in the direction orthogonal to the bonding surface is plural. When the half of the length of the piezoelectric element unit 3 composed of the piezoelectric element 4 and the bonding material for bonding the piezoelectric elements 4 is h2,
When h1 <h2, the L / A ratio is 0.6 ≦ L / A ≦ 0.8,
When h1 = h2, the L / A ratio is 0.4 ≦ L / A ≦ 0.6,
When h1> h2, the L / A ratio is 0.8 ≦ L / A ≦ 2.5
Therefore, the stress applied to the piezoelectric element 4 can be made equal by reducing the bias depending on the location, the damage of the piezoelectric element 4 can be suppressed, and the ultrasonic transducer and the ultrasonic medical treatment with good vibration transmission efficiency can be achieved. An apparatus can be provided.

  Furthermore, according to the ultrasonic medical device 10 of the present embodiment, the ultrasonic transducer 1 and the probe tip 31 that transmits the ultrasonic vibration generated by the ultrasonic transducer 1 and treats the living tissue are provided. Therefore, the ultrasonic medical device 10 which is compact and has good vibration transmission efficiency can be obtained.

  In addition, this invention is not limited by this embodiment. That is, in the description of the embodiments, many specific details are included for illustration, but those skilled in the art can add various variations and modifications to these details without departing from the scope of the present invention. It will be understood that this is not exceeded. Accordingly, the exemplary embodiments of the present invention have been described without loss of generality or limitation to the claimed invention.

DESCRIPTION OF SYMBOLS 1 ... Ultrasonic vibrator 2 ... Metal block 3 ... Piezoelectric element unit 4 ... Piezoelectric element 5 ... Joint part

Claims (4)

Two metal blocks,
A plurality of piezoelectric elements stacked between the metal blocks;
A bonding material for bonding the metal block, the piezoelectric element, and the piezoelectric elements;
With
The ultrasonic transducer according to claim 1, wherein the metal block and the piezoelectric element are rectangular in a cross section parallel to a joint surface between the metal block and the piezoelectric element. The piezoelectric element is formed such that the coefficient of thermal expansion differs between the long side direction and the short side direction of the rectangle,
2. The ultrasonic transducer according to claim 1, wherein lengths of the long side and the short side are determined according to a thermal warpage amount due to a difference in thermal expansion coefficient between the metal block and the piezoelectric element. The metal block is made of 64 titanium alloy (64Ti),
The piezoelectric element is made of lithium niobate (LiNb03) with a 36-degree rotated Y-cut crystal orientation,
The length of the short side of the metal block and the piezoelectric element on the joint surface is A, the length of the long side is L,
The length of the metal block in the direction orthogonal to the joint surface is h1,
When a half of the length of the piezoelectric element unit composed of the plurality of piezoelectric elements in the direction orthogonal to the bonding surface and the bonding material for bonding the piezoelectric elements is h2,
When h1 <h2, the L / A ratio is 0.6 ≦ L / A ≦ 0.8,
When h1 = h2, the L / A ratio is 0.4 ≦ L / A ≦ 0.6,
When h1> h2, the L / A ratio is 0.8 ≦ L / A ≦ 2.5
The ultrasonic transducer according to claim 2. The ultrasonic transducer according to any one of claims 1 to 3,
A probe tip for treating a living tissue through transmission of ultrasonic vibration generated by the ultrasonic transducer;
An ultrasonic medical device comprising:

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