Method for manufacturing an ultrasonic device, and ultrasonic device

Abstract

This technology allows for fine-tuning of the resonant frequency of ultrasonic devices. [Solution] The method for manufacturing an ultrasonic device includes a joining step and a grinding step. In the joining step, a piezoelectric element is joined to one side of the diaphragm, and a cone is joined to the other side of the diaphragm. In the grinding step, the cone is ground down after the joining step. According to this manufacturing method, the weight of the cone can be finely adjusted by performing the grinding step, and the resonant frequency of the ultrasonic device can be finely adjusted.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing an ultrasonic device and an ultrasonic device.

Background Art

[0002] Patent Document 1 discloses an ultrasonic transducer. This ultrasonic transducer includes a vibrator and a cone. The vibrator has a diaphragm and a piezoelectric element. The cone is fixed to the diaphragm.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In this type of device, the resonance frequency changes due to the weight of the cone. Therefore, it is conceivable to form the cone so that the resonance frequency becomes a desired value. However, the resonance frequency may deviate from the desired value due to manufacturing errors or the like.

[0005] An object of the present disclosure is to provide a technique capable of finely adjusting the resonance frequency of an ultrasonic device.

Means for Solving the Problems

[0008] According to this disclosure, the resonant frequency of the ultrasonic device can be finely adjusted. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a flowchart showing the manufacturing process of the ultrasonic device according to the first embodiment. [Figure 2] Figure 2 is a schematic diagram showing the ultrasonic device and laser irradiation device of the first embodiment. [Figure 3] Figure 3 is a plan view of the ultrasonic device before the cutting process in the first embodiment. [Figure 4] Figure 4 is a plan view of the ultrasonic device after the cutting process in the first embodiment. [Figure 5] Figure 5 is a plan view of the ultrasonic device according to the second embodiment. [Figure 6] Figure 6 is a plan view of the ultrasonic device according to the third embodiment. [Figure 7] Figure 7 is a cross-sectional view of the ultrasonic device of the fourth embodiment, obtained by cutting it through the first virtual plane. [Figure 8] Figure 8 is a flowchart showing the manufacturing process of the ultrasonic device according to the fifth embodiment. [Modes for carrying out the invention]

[0010] [Description of Embodiments in this Disclosure] The embodiments of this disclosure are listed and illustrated below.

[0011] [1] A bonding step of bonding a piezoelectric element to one side of the diaphragm and a cone to the other side of the diaphragm, The process includes, after the joining process, a trimming process for trimming the cone. A method for manufacturing an ultrasonic device.

[0012] According to this manufacturing method, by performing a shaving process, the weight of the cone can be finely adjusted, and the resonance frequency of the ultrasonic device can be finely adjusted.

[0013] 〔2〕The cone has a cone body and a weight adjustment material applied to the cone body. In the shaving process, the weight adjustment material is shaved. The manufacturing method of the ultrasonic device according to 〔1〕.

[0014] According to this manufacturing method, the weight of the cone can be finely adjusted without shaving the cone body.

[0015] 〔3〕The cone body is made of metal. The weight adjustment material is made of resin. The manufacturing method of the ultrasonic device according to 〔2〕.

[0016] " According to this manufacturing method, since the weight adjustment material that is easier to shave than the cone body is shaved, it is easier to perform fine adjustment.

[0017] 〔4〕In the shaving process, the cone is shaved by a device that performs laser irradiation or electric discharge. The manufacturing method of the ultrasonic device according to any one of 〔1〕to 〔3〕.

[0018] According to this manufacturing method, it is easy to perform fine processing.

[0019] 〔5〕In the shaving process, on a first virtual plane along the arrangement direction in which the piezoelectric element, the diaphragm, and the cone are arranged and passing through the center of the cone, both sides sandwiching the center of the cone are shaved. The manufacturing method of the ultrasonic device according to any one of 〔1〕to 〔4〕.

[0020] According to this manufacturing method, since both sides sandwiching the center of the cone are shaved on the first virtual plane, compared with the case where only one side is shaved on the first virtual plane, the weight is less likely to be biased to one side on the first virtual plane.

[0021] [6] In the cutting process, the sides on either side of the center of the cone are cut on a second virtual plane that is perpendicular to the first virtual plane and passes through the center of the cone. A method for manufacturing the ultrasonic device described in [5].

[0022] According to this manufacturing method, since both sides of the cone's center are shaved on the second virtual plane, the weight distribution on the second virtual plane is less likely to be biased to one side compared to the case where only one side is shaved on the second virtual plane.

[0023] [7] In the cutting process, the cone is cut in an annular shape around its center. A method for manufacturing the ultrasonic device described in [6].

[0024] According to this manufacturing method, the weight is less likely to be unevenly distributed in the circumferential direction of the cone.

[0025] [8] In the grinding process, the device grinds the cone while checking the frequency characteristics of the ultrasonic device, and stops grinding when the desired frequency characteristics are obtained. A method for manufacturing the ultrasonic device described in [4].

[0026] This manufacturing method allows the cutting process to be automatically stopped once the desired frequency characteristics are obtained.

[0027] [9] Diaphragm and, A piezoelectric element is bonded to one side surface of the diaphragm, The diaphragm comprises a cone joined to the other side surface, The cone has a recess formed therein. Ultrasonic device.

[0028] In this configuration, the resonant frequency of the ultrasonic device is finely tuned by the recesses formed in the cone.

[0029]

[10] The cone comprises a cone body and a weight adjustment material applied to the cone body, The weight adjustment material has a recess formed therein. The ultrasonic device described in [9].

[0030] In this configuration, the resonant frequency of the ultrasonic device is finely tuned by the recesses formed in the weight adjustment material.

[0031] [Details of the embodiments of this disclosure] 1. First Embodiment 1-1. Method for manufacturing an ultrasonic device First, in step S11 of Figure 1, the joining process is performed. In the joining process, as shown in Figure 2, the piezoelectric element 12 is joined to one side of the diaphragm 11, and the cone 13 is joined to the other side of the diaphragm 11.

[0032] The diaphragm 11 is made of, for example, metal. The diaphragm 11 is, for example, plate-shaped. The diaphragm 11 has a first surface 11A and a second surface 11B. The first surface 11A is one side of the diaphragm 11 in the thickness direction. The second surface 11B is the other side of the diaphragm 11 in the thickness direction.

[0033] The piezoelectric element 12 is composed of a piezoelectric body and electrodes positioned on both sides of the pressure voltage. The piezoelectric element 12 is joined to the first surface 11A. In this specification, joining includes not only configurations where the elements are directly joined, but also configurations where they are joined via another member.

[0034] The cone 13 is joined to the second surface 11B. The cone 13 has a cone body 13A and a weight-adjusting material 13B applied to the cone body 13A. The cone body 13A is made of metal, for example. The cone body 13A has a joint portion 20 and an expanded portion 21. The joint portion 20 is the part that is joined to the diaphragm 11. The expanded portion 21 is cylindrical in shape, with its inner diameter increasing as it moves away from the diaphragm 11. One end of the expanded portion 21 is connected to the outer circumference of the joint portion 20. The other end of the expanded portion 21 is open. The weight-adjusting material 13B is made of resin, for example. The weight-adjusting material 13B is applied to the inner surface of the cone body 13A, as shown in Figures 2 and 3. The weight-adjusting material 13B is applied to the inner surface of the cone body 13A, excluding the open end. The step of applying the weight adjustment material 13B to the cone body 13A may be performed before joining the cone body 13A to the diaphragm 11, or it may be performed after joining the cone body 13A to the diaphragm 11.

[0035] The diaphragm 11, piezoelectric element 12, and cone 13 are stacked on top of each other. The direction in which the diaphragm 11, piezoelectric element 12, and cone 13 are arranged is the same as the thickness direction of the diaphragm 11.

[0036] Through this joining process, the ultrasonic device 10 shown in Figures 2 and 3 before the grinding process is manufactured. After the joining process, a grinding process is performed to grind the cone 13. The grinding process is performed using, for example, the laser irradiation device 50 shown in Figure 2. The laser irradiation device 50 is an example of such a device.

[0037] The laser irradiation device 50 includes a mounting base 51, an irradiation unit 52, a power supply unit 53, and a control unit 54. The ultrasonic device 10 is mounted on the mounting base 51. The irradiation unit 52 irradiates with a laser under the control of the control unit 54. At least one of the mounting base 51 and the irradiation unit 52 is configured to be displaceable. At least one of the mounting base 51 and the irradiation unit 52 is controlled by the control unit 54 to be displaceable relative to it. The control unit 54 irradiates the irradiation unit 52 with a laser while displacing the mounting base 51 and the irradiation unit 52 relative to each other. As a result, the laser is irradiated onto the cone 13 in a predetermined pattern. The power supply unit 53 applies a predetermined AC voltage to the piezoelectric element 12 of the ultrasonic device 10.

[0038] In step S12 of Figure 1, when the cutting process begins, the laser irradiation device 50 irradiates the cone 13 with a laser to cut the cone 13. The control unit 54 controls the laser irradiation device 50 so that the laser is irradiated according to a pre-stored irradiation pattern. In the first embodiment, the irradiation pattern is a pattern that cuts both sides of the center C of the cone 13 on the first virtual plane VL1. The first virtual plane VL1 is a virtual plane that is aligned along the direction of the arrangement of the diaphragm 11, piezoelectric element 12, and cone 13, and passes through the center C of the cone 13. By controlling the laser irradiation device 50 according to this irradiation pattern, as shown in Figure 4, both sides of the cone 13 (more specifically, the weight adjustment material 13B) on the first virtual plane VL1, with the center C in between, are cut. As a result, recesses 30 and 31 are formed in the cone 13 (more specifically, the weight adjustment material 13B).

[0039] After the grinding process has started, the control unit 54 continues to apply a predetermined AC voltage to the power supply unit 53 while irradiating the irradiation unit 52 with a laser. The predetermined AC voltage is set, for example, so that its frequency matches the target resonant frequency of the ultrasonic device 10. In step S13, the control unit 54 checks the frequency characteristics of the ultrasonic device 10, and in step S14, it determines whether the desired frequency characteristics have been obtained. For example, the control unit 54 measures the impedance of the ultrasonic device 10. The control unit 54 then determines whether the desired frequency characteristics have been obtained by determining whether the impedance is below a predetermined value, above a predetermined value, whether the decreasing trend of the impedance has stopped, or whether the increasing trend of the impedance has stopped.

[0040] If the control unit 54 determines that the desired frequency characteristics cannot be obtained, it repeats steps S13 and S14 until the desired frequency characteristics are obtained. The control unit 54 repeats steps S13 and S14 while performing the grinding process. The control unit 54 may or may not provide an interval between performing step S14 and performing steps S13 and S14 again. In the first embodiment, as shown in Figure 4, the laser is irradiated to draw one straight line on each side of the center C of the cone 13, and the desired frequency characteristics are obtained when the second straight line is being drawn.

[0041] If the control unit 54 determines that the desired frequency characteristics have been obtained, the laser irradiation by the irradiation unit 52 is stopped in step S15, and the grinding process is completed.

[0042] 1-2. Effects According to this manufacturing method, the weight of the cone 13 can be finely adjusted by performing a grinding process, thereby finely adjusting the resonant frequency of the ultrasonic device 10. Moreover, since the weight adjustment material 13B applied to the cone body 13A is ground away, the weight of the cone 13 can be finely adjusted without grinding away the cone body 13A. Furthermore, since the weight adjustment material 13B is made of resin, it is easier to grind away than the metal cone body 13A. For this reason, fine adjustment is easier.

[0043] In the machining process, the cone 13 is machined using a laser irradiation device 50. This makes it easy to perform fine machining.

[0044] In the machining process, both sides of the cone 13, with the center C in between, are machined on the first virtual plane VL1. Therefore, compared to the case where only one side is machined on the first virtual plane VL1, the weight is less likely to be unevenly distributed on the first virtual plane VL1.

[0045] 2. Second Embodiment In the second embodiment, an example is described in which both sides of the center of the cone are removed on a second virtual plane that is orthogonal to the first virtual plane. Components identical to those in the first embodiment are denoted by the same reference numerals, and detailed explanations are omitted.

[0046] In the second embodiment, as shown in Figure 5, the ultrasonic device 210 is used to remove material from both sides of the center C of the cone 13, not only on the first virtual plane VL1 but also on the second virtual plane VL2. The second virtual plane VL2 is a virtual plane that is perpendicular to the first virtual plane VL1 and passes through the center C of the cone 13. The manufacturing method of the ultrasonic device in the second embodiment is the same as that of the ultrasonic device in the first embodiment in all other respects.

[0047] In the machining process of the second embodiment, both sides of the cone 13 (more specifically, the weight adjustment material 13B) with the center C on the first virtual plane are machined, and both sides of the cone 13 (more specifically, the weight adjustment material 13B) with the center C on the second virtual plane VL2 are also machined. This forms recesses 30, 31, 32, and 33. Recess 30 is continuous with recesses 32 and 33. Recess 31 is continuous with recesses 32 and 33.

[0048] In the second embodiment, as shown in Figure 5, the laser is irradiated in a manner that traces four straight lines, and the desired frequency characteristics are obtained when the fourth straight line is being traced.

[0049] According to this manufacturing method, both sides of the center C of the cone 13 are shaved off on the second virtual plane VL2, so the weight is less likely to be unevenly distributed on the second virtual plane VL2 compared to the case where only one side is shaved off on the second virtual plane VL2.

[0050] 3. Third Embodiment In the third embodiment, an example in which the cone is shaved in an annular pattern around its center will be described. Note that components identical to those in the first embodiment are denoted by the same reference numerals, and detailed explanations are omitted.

[0051] In the machining process of the third embodiment, the weight adjustment material 13B around the center C of the cone 13 is machined into an annular shape (more specifically, a circular shape), as shown in the ultrasonic device 310 in Figure 6. This forms a recess 35. According to this manufacturing method, the weight of the cone 13 is less likely to be unevenly distributed in the circumferential direction.

[0052] 4. Fourth Embodiment In the fourth embodiment, an example is described in which the weight balance of the cone is intentionally biased to tilt the direction of ultrasonic wave transmission. Components identical to those in the first embodiment are denoted by the same reference numerals, and detailed explanations are omitted.

[0053] In the machining process of the fourth embodiment, as shown in Figure 7, only one side is machined on a first virtual plane VL1 that is aligned with the alignment direction and passes through the center C of the cone 13. As a result, recesses 36 and 37 are formed on only one side. Consequently, the weight on the side where the recesses 36 and 37 are formed becomes relatively lighter, and ultrasonic waves are transmitted in the diagonal direction indicated by the arrow in Figure 7.

[0054] 5. Fifth Embodiment In the first embodiment, an example was described in which the frequency characteristics were checked while performing the cutting process and it was determined whether or not the desired frequency characteristics were obtained. In contrast, in the fifth embodiment, an example is described in which the cutting process is interrupted when checking the frequency characteristics and determining whether or not the desired frequency characteristics were obtained. The configuration of the ultrasonic device and laser irradiation device in the fifth embodiment is the same as the configuration shown in Figure 2 described in the first embodiment. Therefore, the fifth embodiment will be described with reference to Figure 2.

[0055] The manufacturing method for the ultrasonic device 10 of the fifth embodiment is as follows. First, a bonding process is performed in step S21 in Figure 8, and a cutting process is started in step S22.

[0056] After starting the cutting process, the control unit 54 determines in step S23 whether or not the determination condition has been met. The determination condition may be, for example, that a predetermined time has elapsed, or it may be another condition. If the control unit 54 determines that the determination condition has not been met, it returns to the process in step S23. In other words, the control unit 54 repeats the process in step S23 until the determination condition is met. During this time, the control unit 54 continues the cutting process.

[0057] If the control unit 54 determines that the determination condition has been met, it interrupts the cutting process in step S24. Then, in step S25, the control unit 54 checks the frequency characteristics of the ultrasonic device 10, and in step S26, it determines whether or not the desired frequency characteristics have been obtained.

[0058] If the control unit 54 determines that the desired frequency characteristics cannot be obtained, it restarts the cutting process in step S27 and returns to the process in step S23. In other words, the control unit 54 alternates between the cutting process and the processes in steps S25 and S26 until the desired frequency characteristics are obtained. The control unit 54 may also change the determination condition (for example, the time until the determination condition is met) based on the frequency characteristics confirmed in step S25.

[0059] If the control unit 54 determines that the desired frequency characteristics have been obtained, the laser irradiation by the irradiation unit 52 is stopped in step S28, and the grinding process is completed.

[0060] <Other Embodiments> The present invention is not limited to the embodiments described above and in the drawings, and the following embodiments, for example, are also included in the technical scope of the present invention. Furthermore, the various features of the embodiments described above and those described later may be combined in any way as long as they are not contradictory.

[0061] (1) The device for cutting the cone does not have to be a laser irradiation device. For example, the device for cutting the cone may be a device that performs electrical discharge. (2) In the above embodiments, the configuration involved removing only the weight adjustment material from the cone, but it is also possible to remove both the cone body and the weight adjustment material. (3) The cone may be configured without weight-adjusting material. In this case, the cone body is trimmed.

[0062] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is not limited to the embodiments disclosed herein, and is intended to include all modifications within the scope set forth in the claims or equivalents thereof. [Explanation of Symbols]

[0063] 10...Ultrasonic device 11...Diaphragm 11A...Side 1 11B…Second side 12... Piezoelectric element 13...corn 13A... Cone body 13B…Weight adjustment material 20…Joint part 21...Expanded section 30…recess 31…recess 32…recess 33…recess 35…recess 36…recess 37…recess 50…Laser irradiation device 51…Installation stand 52... Irradiation area 53...Power supply section 54... Control Unit 210...Ultrasonic device 310...Ultrasonic device 410...Ultrasonic device C…center VL1…First virtual plane VL2...Second virtual plane

Claims

1. A bonding step involves bonding a piezoelectric element to one side of the diaphragm and bonding a cone to the other side of the diaphragm, The process includes, after the joining process, a trimming process for trimming the cone. A method for manufacturing an ultrasonic device.

2. The cone comprises a cone body and a weight-adjusting material applied to the cone body. In the aforementioned cutting process, the weight adjustment material is cut. A method for manufacturing an ultrasonic device according to claim 1.

3. The cone body is made of metal, The aforementioned weight adjustment material is made of resin. A method for manufacturing an ultrasonic device according to claim 2.

4. In the aforementioned cutting process, the cone is cut using a device that performs laser irradiation or electrical discharge. A method for manufacturing an ultrasonic device according to any one of claims 1 to 3.

5. In the aforementioned cutting process, the sides of the cone on either side of the center are cut along the direction in which the piezoelectric element, the diaphragm, and the cone are arranged, and on a first virtual plane that passes through the center of the cone. A method for manufacturing an ultrasonic device according to any one of claims 1 to 3.

6. In the aforementioned cutting process, the sides of the cone on either side of the center are cut on a second virtual plane that is perpendicular to the first virtual plane and passes through the center of the cone. A method for manufacturing an ultrasonic device according to claim 5.

7. In the aforementioned trimming process, the cone is trimmed in an annular shape around its center. A method for manufacturing an ultrasonic device according to claim 6.

8. In the aforementioned grinding process, the device grinds the cone while checking the frequency characteristics of the ultrasonic device, and stops grinding when the desired frequency characteristics are obtained. A method for manufacturing an ultrasonic device according to claim 4.

9. The diaphragm and A piezoelectric element is bonded to one side surface of the diaphragm, The diaphragm comprises a cone joined to the other side surface, The cone has a recess formed therein. Ultrasonic device.

10. The cone comprises a cone body and a weight-adjusting material applied to the cone body. The weight adjustment material has a recess formed therein. The ultrasonic device described in claim 9.

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