Ultrasonic Transducer

Abstract

To provide an ultrasonic transducer that makes it easy to stabilize the relative positional relationship between transducers.SOLUTION: An ultrasonic transducer 1 includes a plurality of vibrators each having a plurality of piezoelectric elements and a diaphragm 20 bonded to the piezoelectric elements, and a connecting portion 30 that connects the diaphragms 20 of the respective vibrators. The width of the connecting portion 30 is smaller than the width of the diaphragm 20, and the connecting portion 30 includes a first connecting portion 31 that connects the diaphragms 20 arranged side by side in the X direction, and a second connecting portion 32 that connects the diaphragms 20 arranged side by side in the Y direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an ultrasonic transducer. [Background technology]

[0002] Patent Document 1 discloses a parametric speaker. This parametric speaker includes a substrate and a plurality of ultrasonic sound generating bodies (vibrators). The plurality of ultrasonic sound generating bodies (vibrators) are individually installed on the substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-175935 Summary of the Invention [Problem to be solved by the invention]

[0004] In a configuration in which a plurality of vibrators are individually mounted on a substrate, as in Patent Document 1, it is difficult to stabilize the relative positional relationship between the vibrators.

[0005] An object of the present invention is to provide a technique that makes it easier to stabilize the relative positional relationship between transducers. [Means for solving the problem]

[0006] [1] The ultrasonic transducer of the present invention includes a plurality of vibrators and a connecting portion that connects the vibrators to each other. The vibrators have a piezoelectric element and a vibration plate bonded to the piezoelectric element. The connecting portion connects the vibration plates to each other. The width of the connecting portion is smaller than the width of the vibration plate.

[0007] With this configuration, the vibrators are connected to each other by the connecting portions, which makes it easy to stabilize the relative positional relationship between the vibrators. Moreover, the vibrators are connected to each other by connecting the diaphragms that make up the vibrators, and the width of the connecting portions that connect the diaphragms to each other is smaller than the width of the diaphragms. Therefore, it is possible to suppress the transmission of vibration between the diaphragms via the connecting portions.

[0008] [2] The vibration plate may have a notch cut inward from the outer edge of the vibration plate, the connecting portion may be connected to a part of the inner surface of the notch, and a recess opening to the outer periphery of the vibration plate may be formed between the inner surface of the notch and the connecting portion.

[0009] When the diaphragm vibrates, annular nodes are formed on the diaphragm, and the vibration increases as it moves from the nodes toward the outer periphery. Therefore, when the connecting portion is connected to the outer periphery of the diaphragm, the large vibration at the outer periphery is transmitted to the connecting portion. However, with the above configuration, the connecting portion is connected to a part of the inner surface of a notch cut inward from the outer periphery of the diaphragm, and a recess opening to the outer periphery of the diaphragm is formed between the inner surface of the notch and the connecting portion. This prevents the large vibration at the outer periphery from being transmitted directly to the connecting portion. Therefore, the transmission of vibration between diaphragms via the connecting portion can be further suppressed.

[0010] [3] The ultrasonic transducer may include a base and a plurality of intervening members. The intervening members may be annular, disposed between the vibrator and the base, and bonded to both the vibrator and the base. The bottom of the recess may be located between an inscribed circle inscribed in the intervening member and a circumscribed circle circumscribed in the intervening member in a planar direction perpendicular to the thickness direction of the diaphragm.

[0011] Since the vibrator is joined to the base portion via the intervening member, the portion where the intervening member is joined is less likely to vibrate. In the above configuration, the bottom of the recess is located between the inscribed circle inscribed in the intervening member and the circumscribed circle circumscribed around the intervening member in the planar direction, i.e., in a portion where the diaphragm is less likely to vibrate. Therefore, the connecting portion is connected at a portion where the diaphragm is less likely to vibrate. Therefore, it is possible to further suppress the transmission of vibration between the diaphragms via the connecting portion.

[0012] [4] The interposing member may be arranged such that a vibration node of the diaphragm is located between an inscribed circle inscribed in the interposing member and a circumscribed circle circumscribed around the interposing member in the planar direction.

[0013] With this configuration, the intervening member is less likely to impede the vibration of the diaphragm. Moreover, since the connecting portion is connected near the vibration node of the diaphragm, the transmission of vibration between the diaphragms via the connecting portion can be further suppressed.

[0014] [5] The connecting portion may protrude beyond the diaphragm in the thickness direction of the diaphragm.

[0015] According to this configuration, it is possible to lengthen the connecting portion while suppressing the expansion of the ultrasonic transducer in a planar direction perpendicular to the thickness direction of the diaphragm.

[0016] [6] The diaphragm and the connecting portion may be electrically conductive. The ultrasonic transducer may have a wiring portion that connects the diaphragm or the connecting portion to a conductive path. The number of wiring portions may be one or more and less than the number of diaphragms.

[0017] According to this configuration, all of the diaphragms connected by the connecting portions can be electrically connected to the conductive paths using a smaller number of wiring portions than the number of diaphragms. [Effects of the Invention]

[0018] According to the present invention, the relative positional relationship between the vibrators is likely to be stabilized. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an ultrasonic transducer according to a first embodiment. [Figure 2] FIG. 2 is a plan view showing a state in which a plurality of diaphragms are connected by connecting portions. [Figure 3] FIG. 3 is an enlarged view of the diaphragm and the connecting portion. [Figure 4] FIG. 4 is a cross-sectional view schematically showing an ultrasonic transducer according to the second embodiment. [Figure 5] FIG. 5 is a cross-sectional view schematically showing an ultrasonic transducer according to the third embodiment. [Figure 6] FIG. 6 is a plan view showing a state in which a plurality of diaphragms according to the fourth embodiment are connected by connecting portions. DETAILED DESCRIPTION OF THE INVENTION

[0020] 1. First embodiment The ultrasonic transducer 1 shown in Figure 1 is used in, for example, medical or industrial ultrasonic devices. The ultrasonic transducer 1 generates ultrasonic waves when a drive signal is applied, and converts the received ultrasonic waves into electrical signals.

[0021] The ultrasonic transducer 1 includes a plurality of vibrators 11, a plurality of resonators 12, a plurality of intervening members 13, a base portion 14, a wiring portion 15, a plurality of second wiring portions 16, and a case 17.

[0022] The vibrator 11 has a vibration plate 20 and a piezoelectric element 21. The vibration plate 20 and the piezoelectric element 21 are each plate-shaped, arranged so as to overlap each other, and bonded to each other. In this specification, the term "bonded" is used to refer not only to a direct bonded structure, but also to a bonded structure via another member.

[0023] The diaphragm 20 is conductive and made of, for example, metal. The diaphragm 20 is disk-shaped. The width (maximum width) W1 of the diaphragm 20 is larger than the widths (maximum widths) of the resonator 12, the intervening member 13, and the piezoelectric element 21. The width (maximum width) W1 of the diaphragm 20 refers to the length (maximum length) in a direction perpendicular to the thickness direction of the diaphragm 20. In this embodiment, the width (maximum width) W1 of the diaphragm 20 is the diameter of the outer periphery of the diaphragm 20.

[0024] The diaphragm 20 vibrates to generate annular (more specifically, circular) nodes 22. The nodes 22 are the portions where the amount of displacement in the thickness direction of the diaphragm 20 is smallest when the diaphragm 20 vibrates, or the portions where there is no vibration. The nodes 22 are uniquely determined by the shapes and materials of the vibrator 11 and the resonator 12. The outer periphery of the diaphragm 20 is a free end. In other words, the ultrasonic transducer 1 is a so-called open type, which is more susceptible to vibration than a closed type in which the outer periphery of the diaphragm 20 is fixed. The nodes 22 are generated inside the outer periphery of the diaphragm 20 and outside the center in a plane direction perpendicular to the thickness direction. The vibration of the diaphragm 20 increases from the nodes 22 toward the periphery and from the nodes 22 toward the center.

[0025] The resonator 12 is bonded to one surface of the diaphragm 20 in the thickness direction, and the piezoelectric element 21 is bonded to the other surface.

[0026] The resonator 12 resonates with the vibration of the diaphragm 20 to generate ultrasonic waves. The resonator 12 is cone-shaped. The resonator 12 has a flat portion 12A and a tapered portion 12B. The flat portion 12A is flat and has a plate shape (more specifically, a disk shape). The flat portion 12A is joined to one surface of the diaphragm 20 in the thickness direction. The tapered portion 12B extends in a cylindrical shape from the outer periphery of the flat portion 12A toward the opposite side to the diaphragm 20 side. The inner periphery of the tapered portion 12B has a tapered shape that widens as it approaches the opposite side to the diaphragm 20 side.

[0027] The piezoelectric element 21 has a rectangular shape when viewed in the thickness direction of the diaphragm 20. The piezoelectric element 21 has a plate-shaped piezoelectric body 21A and electrodes 21B and 21C provided on both sides of the piezoelectric body 21A in the thickness direction. The piezoelectric body 21A is made of piezoelectric ceramics. Of the electrodes 21B and 21C provided on both sides of the piezoelectric element 21, one electrode 21B is bonded to the diaphragm 20 and electrically connected to the wiring portion 15 via the diaphragm 20. Of the electrodes 21B and 21C provided on both sides of the piezoelectric element 21, the other electrode 21C is electrically connected to the second wiring portion 16. A base portion 14 is bonded via an intervening member 13 to a surface of the piezoelectric element 21 opposite to the diaphragm 20 side (i.e., the surface of the vibrator 11 opposite to the resonator 12 side).

[0028] Intervening member 13 is disposed between vibrator 11 (more specifically, piezoelectric element 21) and base portion 14, and is bonded to both vibrator 11 (more specifically, piezoelectric element 21) and base portion 14. Intervening member 13 is insulating and elastic. Intervening member 13 is made of, for example, rubber or resin mixed with carbon black or calcium carbonate. Intervening member 13 is annular (more specifically, circular). The axial direction of intervening member 13 is aligned with the thickness direction of diaphragm 20, and more specifically, is the same as the thickness direction of diaphragm 20. Intervening member 13 is disposed such that, in a planar direction perpendicular to the thickness direction of diaphragm 20, vibration node 22 of diaphragm 20 is located between inscribed circle 13A inscribed in intervening member 13 and circumscribed circle 13B circumscribed in intervening member 13 (see FIG. 3).

[0029] The base portion 14 is made of synthetic resin and configured as a resin base. The base portion 14 is plate-shaped. The thickness direction of the base portion 14 is along the thickness direction of the diaphragm 20, more specifically, the same as the thickness direction of the diaphragm 20. The multiple vibrators 11 are bonded to one surface of the base portion 14 in the thickness direction. The multiple vibrators 11 are arranged along a plane direction perpendicular to the thickness direction.

[0030] The wiring portion 15 has a metal terminal 15A. The wiring portion 15 is electrically connected to the diaphragm 20. The wiring portion 15 is also electrically connected to one of the positive and negative conductive paths (e.g., ground). In other words, the wiring portion 15 electrically connects the diaphragm 20 to the one conductive path.

[0031] The second wiring portion 16 has a metal terminal 16A and a coil spring 16B. A base through-hole 14A is formed in the base portion 14, penetrating in the thickness direction. The second wiring portion 16 is inserted through the base through-hole 14A. The terminal 16A is fixed to the base portion 14 at a position that closes the opening of the base through-hole 14A on the side opposite to the diaphragm 20 side. The direction of expansion and contraction of the coil spring 16B is along the thickness direction of the diaphragm 20, more specifically, the same as the thickness direction. The coil spring 16B is sandwiched and disposed between the piezoelectric element 21 and the terminal 16A, and is disposed in a compressed state by being pressed by the piezoelectric element 21 and the terminal 16A. One end of the coil spring 16B contacts the surface of the piezoelectric element 21 opposite to the diaphragm 20 side (i.e., the electrode 21C of the piezoelectric element 21), and the other end contacts the terminal 16A. The second wiring portion 16 is electrically connected to the other of the positive electrode side conductive path and the negative electrode side conductive path (for example, ground).

[0032] The case 17 is a member that protects the vibrator 11 and the resonator 12 to prevent foreign objects from coming into contact with the vibrator 11 and the resonator 12. The case 17 is fixed to the base 14. The case 17 has a peripheral wall 17A that surrounds the vibrator 11 and the resonator 12. A plurality of openings are formed in the case 17 on the side opposite the base 14 side of the resonator 12, and ultrasonic waves are sent to the outside through these openings and enter the case 17 from the outside.

[0033] As shown in FIGS. 1 and 2, the ultrasonic transducer 1 includes a connecting portion 30. The connecting portion 30 connects the vibrators 11 to each other. More specifically, the connecting portion 30 connects the diaphragms 20 to each other. The connecting portion 30 is conductive and is made of, for example, metal. The width W2 of the connecting portion 30 is smaller than the width (maximum width) W1 of the diaphragm 20. The connecting portion 30 and the diaphragm 20 have the same thickness. Both surfaces of the connecting portion 30 in the thickness direction are flat and flush with both surfaces of the diaphragm 20 in the thickness direction. The connecting portion 30 is formed integrally with the diaphragm 20 from the same material. The diaphragm 20 and the connecting portion 30 are formed, for example, by punching a metal plate. Note that if the connecting portion 30 does not have a constant width, the width W2 of the connecting portion 30 refers to the width at the portion where the width is greatest.

[0034] 2, the diaphragm 20 has a notch 40 cut inward from the outer periphery of the diaphragm 20. A plurality of notches 40 (four in this embodiment) are provided along the circumferential direction of the diaphragm 20. A connecting portion 30 is connected to the inner surface of the notch 40.

[0035] As shown in FIG. 2, the diaphragms 20 are arranged side by side along a planar direction perpendicular to the thickness direction. The X and Y directions intersect each other in the planar directions perpendicular to the thickness direction of the diaphragms 20 (in this embodiment, they are perpendicular). The diaphragms 20 are arranged side by side along the X and Y directions. The notches 40 are formed on both sides of the diaphragm 20 in the X direction and on both sides of the diaphragm 20 in the Y direction. The connecting portion 30 has a first connecting portion 31 that connects the diaphragms 20 arranged side by side in the X direction, and a second connecting portion 32 that connects the diaphragms 20 arranged side by side in the Y direction. The first connecting portion 31 and the second connecting portion 32 are connected by crossing each other. The connecting portion 30 has a curved portion when viewed from the thickness direction of the diaphragm 20. More specifically, as shown in Figure 3, the connecting portion 30 has a straight portion 30A that extends linearly from the inner surface of the cutout portion 40, and a bent portion 30B that extends bent from the end of the straight portion 30A opposite the cutout portion 40 side.

[0036] As shown in Fig. 3, a recess 41 is formed between the inner surface of the cutout 40 and the connecting portion 30. A bottom 41A of the recess 41 is located between an inscribed circle 13A that inscribes the intervening member 13 and a circumscribed circle 13B that circumscribes the intervening member 13 in a planar direction perpendicular to the thickness direction of the diaphragm 20. The bottom 41A of the recess 41 refers to the position of the recess 41 that is closest to the center of the diaphragm 20 in the planar direction. The center of the diaphragm 20 refers to the center of the circumscribed circle that circumscribes the diaphragm 20.

[0037] As shown in Fig. 1, the plurality of diaphragms 20 are electrically connected via connecting portions 30. A wiring portion 15 is joined to one of the plurality of diaphragms 20. The wiring portion 15 is electrically connected to one of the positive and negative conductive paths (e.g., ground). In other words, the plurality of diaphragms 20 are electrically connected to the one conductive path by one wiring portion 15.

[0038] The following description relates to the effects of the first embodiment. In the ultrasonic transducer 1 of the first embodiment, the oscillators 11 are connected to each other by the connecting portions 30, which makes it easy to stabilize the relative positional relationship between the oscillators 11. Moreover, the oscillators 11 are connected to each other by connecting the vibration plates 20 that constitute the oscillators 11 to each other, and the width of the connecting portions 30 that connect the vibration plates 20 to each other is smaller than the width of the vibration plates 20. Therefore, it is possible to suppress transmission of vibration between the vibration plates 20 via the connecting portions 30.

[0039] Furthermore, when the diaphragm 20 vibrates, portions that become annular nodes 22 are formed on the diaphragm 20, and the vibration increases toward the outer periphery from the nodes 22. Therefore, when the connecting portion 30 is connected to the outer periphery of the diaphragm 20, the large vibration at the outer periphery is transmitted to the connecting portion 30. However, with the above configuration, the connecting portion 30 is connected to a part of the inner surface of a notch 40 that is cut inward from the outer periphery of the diaphragm 20, and a recess 41 that opens toward the outer periphery of the diaphragm 20 is formed between the inner surface of the notch 40 and the connecting portion 30. This prevents the large vibration at the outer periphery from being transmitted directly to the connecting portion 30. Therefore, the transmission of vibration between the diaphragms 20 via the connecting portion 30 can be further suppressed.

[0040] Furthermore, because vibrator 11 is joined to base portion 14 via intervening member 13, the portion where intervening member 13 is joined is less likely to vibrate. In the above configuration, bottom 41A of recess 41 is disposed between inscribed circle 13A inscribed in intervening member 13 and circumscribed circle 13B circumscribed therearound, in the above-mentioned planar direction, in other words, in a portion where diaphragm 20 is less likely to vibrate. Therefore, connecting portion 30 connects diaphragms 20 at a portion where diaphragms 20 are less likely to vibrate. Therefore, transmission of vibration between diaphragms 20 via connecting portion 30 can be further suppressed.

[0041] Furthermore, intervening member 13 is arranged such that, in a planar direction perpendicular to the thickness direction of diaphragm 20, vibration node 22 of diaphragm 20 is located between inscribed circle 13A that inscribes intervening member 13 and circumscribed circle 13B that circumscribes intervening member 13. For this reason, intervening member 13 is unlikely to inhibit the vibration of diaphragm 20. Moreover, because connecting portion 30 is connected to diaphragm 20 near vibration node 22, transmission of vibration between diaphragms 20 via connecting portion 30 can be further suppressed.

[0042] Furthermore, the diaphragm 20 and the connecting portion 30 are each conductive, and the wiring portion 15 connects the diaphragm 20 to the conductive path. The number of wiring portions 15 is one, which is less than the number of diaphragms 20. Therefore, all of the diaphragms 20 connected by the connecting portion 30 can be electrically connected to the conductive path using wiring portions 15 that are fewer in number than the diaphragms 20.

[0043] Second Embodiment The ultrasonic transducer 201 of the second embodiment differs from the ultrasonic transducer 1 of the first embodiment in that the connecting portion 230 protrudes in the thickness direction beyond the diaphragm 20, but is otherwise common to both. In the following description, the same components as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0044] 4, the ultrasonic transducer 201 of the second embodiment has a connecting portion 230. The connecting portion 230 protrudes in a direction away from the base portion 14 beyond the diaphragm 20. With this configuration, the connecting portion 230 can be made longer while suppressing the expansion of the ultrasonic transducer 201 in a planar direction perpendicular to the thickness direction of the diaphragm 20.

[0045] Third Embodiment In the ultrasonic transducer 301 of the third embodiment, the protruding direction of the connecting portion 330 is opposite to the protruding direction of the connecting portion 230 of the ultrasonic transducer 201 of the second embodiment. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0046] 5, an ultrasonic transducer 301 of the third embodiment has a connecting portion 330. The connecting portion 330 protrudes in a direction closer to the base portion 14 than the diaphragm 20. With this configuration, it is possible to lengthen the connecting portion 330 while suppressing the expansion of the ultrasonic transducer 301 in a planar direction perpendicular to the thickness direction of the diaphragm 20.

[0047] <Fourth embodiment> The vibration plate 20 of the ultrasonic transducer 1 in the first embodiment has a configuration having a notch 40, but may have a configuration not having the notch 40. Furthermore, the connecting portion 30 of the ultrasonic transducer 1 in the first embodiment has a configuration having a curved portion when viewed from the thickness direction of the vibration plate 20, but may have a configuration not having a curved portion. In the fourth embodiment, an example of a configuration not having a notch 40 and a configuration in which the connecting portion does not have a curved portion will be described.

[0048] 6, in the fourth embodiment, diaphragm 420 does not have notch 40. Furthermore, connecting portion 430 is linear when viewed in the thickness direction of diaphragm 420. With this configuration, diaphragm 420 and connecting portion 430 have simple shapes, which makes it easy to manufacture a mold for forming diaphragm 420 and connecting portion 430.

[0049] <Other embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments are also included within the technical scope of the present invention. Furthermore, the various features of the above-mentioned embodiments and the embodiments to be described later may be combined in any manner as long as they are not contradictory.

[0050] In the above embodiment, the diaphragm and the connecting portion are configured to be conductive, but they may be configured to be insulating.

[0051] In the above embodiment, the connecting portion is formed of the same material as the diaphragm, but it may be formed of a separate material from the diaphragm.

[0052] It should be noted that the embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, but is intended to include all modifications within the scope indicated by the claims or the scope equivalent to the claims. [Explanation of symbols]

[0053] 1...Ultrasonic transducer 11...Oscillator 12...Resonator 13…Intervening member 13A...Inscribed circle 13B…Circumcircle 14...Base 15...Wiring section 20...Diaphragm 21...Piezoelectric element 21A...Piezoelectric body 21B…Electrode 21C…electrode Verse 22 30...Connection part 40...Notch 41...recess 41A...Bottom of recess 201...Ultrasonic transducer 230...Connection part 301...Ultrasonic transducer 330...Connection part 420…Diaphragm 430...Connection part

Claims

1. A plurality of oscillators; a connecting portion that connects the vibrators to each other; Equipped with the vibrator has a piezoelectric element and a vibration plate joined to the piezoelectric element, the connecting portion has the same thickness as the diaphragm; the connecting portion connects the vibration plates to each other and is integrally formed with the plurality of vibration plates using the same member; The width of the connecting portion is smaller than the width of the diaphragm, The width of the diaphragm is the maximum length in a direction perpendicular to the thickness direction of the diaphragm, The width of the connecting portion is the maximum width of the connecting portion in a direction perpendicular to the thickness direction of the connecting portion. Ultrasonic transducer.

2. A plurality of oscillators; a connecting portion that connects the vibrators to each other; Equipped with the vibrator has a piezoelectric element and a vibration plate joined to the piezoelectric element, the connecting portion has the same thickness as the diaphragm; the connecting portion connects the diaphragms to each other, The width of the connecting portion is smaller than the width of the diaphragm, the diaphragm has a notch cut inward from an outer periphery of the diaphragm, the connecting portion is connected to a part of the inner surface of the notch portion, A recess that opens to the outer periphery of the diaphragm is formed between the inner surface of the notch and the connecting portion. Ultrasonic transducer.

3. A base portion and A plurality of intervening members; Equipped with the interposition member is annular, disposed between the vibrator and the base portion, and joined to both the vibrator and the base portion; The bottom of the recess is disposed between an inscribed circle inscribed in the interposition member and a circumscribed circle circumscribed in the interposition member in a planar direction perpendicular to the thickness direction of the diaphragm.

3. The ultrasonic transducer according to claim 2.

4. The intervening member is disposed in the planar direction such that a vibration node of the diaphragm is disposed between the inscribed circle and the circumscribed circle.

4. The ultrasonic transducer according to claim 3.

5. The connecting portion protrudes beyond the diaphragm in a thickness direction of the diaphragm.

5. The ultrasonic transducer according to claim 1.

6. the diaphragm and the connecting portion are conductive; a wiring portion that connects the diaphragm or the connecting portion to a conductive path; The number of the wiring portions is one or more and less than the number of the diaphragms. The ultrasonic transducer according to any one of claims 1 to 5.

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