Ultrasonic vibration device

Abstract

The present invention comprises a part (110) to be vibrated, and at least one vibrator (120). The at least one vibrator (120) is bonded to the part (110) to be vibrated and vibrates the part (110) to be vibrated. The at least one vibrator (120) is configured by laminating a piezoelectric element (121), a pair of resin layers (125, 126) that sandwich the piezoelectric element (121) therebetween, and a pair of metal layers (127, 128) that sandwich the piezoelectric element (121) and the pair of resin layers (125, 126) therebetween. The at least one vibrator (120) vibrates the part (110) to be vibrated in a resonance mode.

Description

Ultrasonic vibration device

[0001] The present invention relates to an ultrasonic vibration device.

[0002] As a prior art document that discloses a panel that generates a tactile sensation by vibration, there is Patent No. 7370190 (Patent Document 1). The panel described in Patent Document 1 includes a diaphragm and a piezoelectric actuator. The piezoelectric actuator is provided on the main surface of the diaphragm and vibrates the diaphragm. The piezoelectric actuator includes a positive electrode, a negative electrode, and a piezoelectric material layer. The piezoelectric actuator is joined to the diaphragm by an adhesive or the like.

[0003] Patent No. 7370190

[0004] When the vibrating part to which the piezoelectric element is adhered is bent and vibrated, the displacement of the vibrating part becomes small due to the influence of the thickness of the adhesive layer.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide an ultrasonic vibration device that can reduce the influence of the thickness of the adhesive layer and stably displace the vibrating part greatly.

[0006] The ultrasonic vibration device according to the present invention includes a vibrating part and at least one vibrator. At least one vibrator is adhered to the vibrating part to vibrate the vibrating part. At least one vibrator is configured by laminating a piezoelectric element, a pair of resin layers that sandwich the piezoelectric element between them, and a pair of metal layers that sandwich the piezoelectric element and the pair of resin layers between them. At least one vibrator vibrates the vibrating part in a resonance mode.

[0007] According to the present invention, the influence of the thickness of the adhesive layer can be reduced and the vibrating part can be stably displaced greatly.

[0008] This is a plan view showing an ultrasonic vibration device according to one embodiment of the present invention. This is a cross-sectional view of the ultrasonic vibration device of Figure 1 taken from the direction of the arrow II-II. This is a side view of the ultrasonic vibration device of Figure 1 taken from the direction of arrow III. This is a cross-sectional view of an ultrasonic vibration device according to a comparative example. This is a graph showing the results of a simulation analysis of the relationship between the amount of displacement of the vibrated part and the thickness of the adhesive layer in the ultrasonic vibration devices according to the example and comparative example. This is a graph showing the results of an actual measurement of the relationship between the vibration frequency of the vibrated part and the impedance of the vibrator in the ultrasonic vibration devices according to the example and comparative example. This is a graph showing the relationship between the target resonance frequency and the impedance of the vibrator. This is a graph showing the results of a simulation analysis of the relationship between the Poisson's ratio of the resin constituting a pair of resin layers and the amount of displacement of the vibrated part in the ultrasonic vibration device according to the example. This is a plan view showing an ultrasonic vibration device according to a modified example of one embodiment of the present invention.

[0009] Hereinafter, an ultrasonic vibration device according to one embodiment of the present invention will be described with reference to the figures. In the following description of the embodiment, the same or corresponding parts in the figures will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0010] Figure 1 is a plan view showing an ultrasonic vibration device according to one embodiment of the present invention. Figure 2 is a cross-sectional view of the ultrasonic vibration device of Figure 1 taken from the direction of the arrow II-II. Figure 3 is a side view of the ultrasonic vibration device of Figure 1 taken from the direction of arrow III.

[0011] As shown in Figures 1 to 3, an ultrasonic vibration device 100 according to one embodiment of the present invention comprises a vibration-receiving part 110 and at least one transducer 120. The vibration-receiving part 110 is a plate-shaped member made of glass or plastic. The vibration-receiving part 110 has a rectangular outer shape when viewed from the thickness direction (Z-axis direction). In the rectangular outer shape of the vibration-receiving part 110, the long side is aligned in the horizontal direction (X-axis direction), and the short side is aligned in the vertical direction (Y-axis direction). The dimensions of the vibration-receiving part 110 are, for example, that the length of the long side is 100 mm or more and 360 mm or less, the length of the short side is 50 mm or more and 180 mm or less, and the thickness T0 is 0.3 mm or more and 3 mm or less.

[0012] At least one vibrator 120 is bonded to the back surface of the vibrating part 110 by an adhesive layer 130. In this embodiment, the adhesive layer 130 is made of an adhesive made of epoxy resin or the like, but is not limited to this, and the adhesive layer 130 may be made of double-sided tape. The thickness T6 of the adhesive layer 130 is, for example, 50 μm or more and 100 μm or less.

[0013] In this embodiment, the ultrasonic vibration device 100 is equipped with a plurality of transducers 120, but is not limited to this, and may be equipped with only one transducer 120. The transducer 120 is rectangular when viewed from the thickness direction (Z-axis direction), but is not limited to this, and may be circular or elliptical.

[0014] As shown in Figure 2, at least one oscillator 120 is constructed by laminating a piezoelectric element 121, a pair of resin layers sandwiching the piezoelectric element 121 between them, and a pair of metal layers sandwiching the piezoelectric element 121 and the pair of resin layers between them.

[0015] The piezoelectric element 121 includes a piezoelectric body 122 and a first electrode layer 123 and a second electrode layer 124 that sandwich the piezoelectric body 122 between them. In this embodiment, the piezoelectric body 122 is made of piezoelectric ceramics such as PZT (lead zirconate titanate) ceramics, but is not limited to this and may be made of other piezoelectric materials. The first electrode layer 123 is directly connected to one side of the piezoelectric body 122 (the side facing the vibrated part 110). The second electrode layer 124 is directly connected to the other side of the piezoelectric body 122 (the side opposite to the vibrated part 110). The piezoelectric element 121 may be constructed by stacking multiple laminates in which a piezoelectric body 122 is sandwiched between a pair of electrode layers. The thickness T1 of the piezoelectric element 121 is, for example, 0.1 mm or more and 0.5 mm or less.

[0016] A pair of resin layers consists of a first resin layer 125 and a second resin layer 126. The first resin layer 125 is located on one side of the piezoelectric element 121 (the side facing the vibrating part 110). The second resin layer 126 is located on the other side of the piezoelectric element 121 (the side opposite to the vibrating part 110). The thickness T2 of the first resin layer 125 and the thickness T3 of the second resin layer 126 are, for example, 0.3 mm or more and 1 mm or less. The thickness T2 of the first resin layer 125 and the thickness T3 of the second resin layer 126 may be the same or different. The thickness T3 of the second resin layer 126 may be thicker than the thickness T2 of the first resin layer 125.

[0017] Each of the first resin layer 125 and the second resin layer 126 is made of acrylic resin. However, the resins constituting each of the first resin layer 125 and the second resin layer 126 are not limited to acrylic resin, and any resin having a Young's modulus of 1 GPa or more and 4 GPa or less at room temperature, and a Poisson's ratio of 0.3 or more and 0.5 or less, is acceptable. The Young's modulus of the resins constituting each of the first resin layer 125 and the second resin layer 126 may be 1.5 GPa or more and 3 GPa or less, or 2 GPa or more and 3 GPa or less.

[0018] A pair of metal layers consists of a first metal layer 127 and a second metal layer 128. The first metal layer 127 is located on one side of the first resin layer 125 (the side facing the vibrated part 110). The first metal layer 127 is bonded to the vibrated part 110 by an adhesive layer 130. The second metal layer 128 is located on the other side of the second resin layer 126 (the side opposite to the vibrated part 110). The thickness T4 of the first metal layer 127 and the thickness T5 of the second metal layer 128 are, for example, 0.3 mm or more and 3 mm or less. In this embodiment, the thickness T5 of the second metal layer 128 is thicker than the thickness T4 of the first metal layer 127. The thickness T5 of the second metal layer 128 is 1.5 times or more and 5 times or less than the thickness T4 of the first metal layer 127. In other words, in a pair of metal layers, one metal layer is thicker than the other metal layer that is bonded to the vibrated part 110. This allows the vibration of the vibrator 120 to be effectively transmitted to the vibrated part 110, thereby increasing the displacement of the vibrated part 110. However, the thickness T4 of the first metal layer 127 and the thickness T5 of the second metal layer 128 may be the same. The first metal layer 127 and the second metal layer 128 are each made of stainless steel, titanium alloy, or aluminum alloy, etc.

[0019] As shown in Figure 3, at least one transducer 120 is attached to the vibrated part 110 and vibrates the vibrated part 110. At least one transducer 120 vibrates the vibrated part 110 in a resonant mode. In the ultrasonic vibration device 100 according to one embodiment of the present invention, the vibrated part 110 is vibrated in a thickness longitudinal vibration mode. As a result, as schematically shown in Figure 3, a standing wave W is generated in the in-plane direction (XY in-plane direction) of the vibrated part 110, where the vibration displaces the vibrated part 110 in the thickness direction (Z axis direction). In Figure 1, a standing wave Wx propagating in the lateral direction (X axis direction) and a standing wave Wy propagating in the longitudinal direction (Y axis direction) are schematically shown. However, depending on the dimensions of the vibrated part 110, the standing wave Wx propagating in the lateral direction (X axis direction) and the standing wave Wy propagating in the longitudinal direction (Y axis direction) may not occur simultaneously.

[0020] As shown in Figures 1 and 3, the multiple vibrators 120 are arranged at both ends of the vibrated part 110 in the lateral direction (X-axis direction) with spacing between them in the vertical direction (Y-axis direction). Alternatively, the multiple vibrators 120 may be arranged at either end of the vibrated part 110 in the lateral direction (X-axis direction) with spacing between them in the vertical direction (Y-axis direction).

[0021] The multiple oscillators 120 are arranged so as to be located at the antinodes of the standing wave W caused by the vibration of the vibrated part 110 in the resonance mode. Specifically, the multiple oscillators 120 are arranged so that the center of each oscillator 120 is located at the antinode of the standing wave Wx, while also being located at the antinode of the standing wave Wy. This makes it possible to increase the displacement of the vibration of the vibrated part 110 in the resonance mode. However, in order to obtain this effect, it is sufficient that the center of each oscillator 120 is located at the antinode of the standing wave Wx, and it is not necessarily required that the center of each oscillator 120 be located at the antinode of the standing wave Wy.

[0022] As shown in Figure 1, the maximum length Lmax of at least one transducer 120 in a direction perpendicular to the stacking direction (Z-axis direction) (in the XY plane) is less than or equal to the wavelength of the bending vibration of at least one transducer 120. This suppresses the vibration of the vibrated part 110 in the bending vibration mode, and allows the vibrated part 110 to vibrate stably in the resonance mode.

[0023] Here, a comparative example of an ultrasonic vibration device will be described to illustrate the effects of the ultrasonic vibration device 100 according to one embodiment of the present invention. The ultrasonic vibration device of the comparative example differs from the ultrasonic vibration device 100 according to one embodiment of the present invention in that the transducer is composed of a piezoelectric element 121. Therefore, the same configuration as the ultrasonic vibration device 100 according to one embodiment of the present invention will not be repeated in the description.

[0024] Figure 4 is a cross-sectional view of an ultrasonic vibration device according to a comparative example. In Figure 4, the cross-sectional view is the same as in Figure 2. As shown in Figure 4, the ultrasonic vibration device 900 according to the comparative example comprises a vibrated part 110 and at least one transducer. In the ultrasonic vibration device 900, the transducer is composed of a piezoelectric element 121. That is, the piezoelectric element 121 is bonded to the back surface of the vibrated part 110 by an adhesive layer 130. This forms a unimorph structure, and in the ultrasonic vibration device 900 according to the comparative example, the vibrated part 110 is vibrated in a bending vibration mode.

[0025] Figure 5 is a graph showing the results of a simulation analysis of the relationship between the displacement of the vibrated part and the thickness of the adhesive layer in the ultrasonic vibration devices according to the example and comparative example. In Figure 5, the vertical axis shows the displacement (Peak to Peak) (μm) of the vibrated part 110, and the horizontal axis shows the thickness of the adhesive layer 130 (μm). The data for the ultrasonic vibration device 100 according to the example is shown by a solid line, and the data for the ultrasonic vibration device 900 according to the comparative example is shown by a dotted line.

[0026] As shown in Figure 5, within the range of adhesive layer thickness 130 from 50 μm to 100 μm, the displacement (pp) of the vibrated part 110 in the comparative ultrasonic vibration device 900 was smaller than the displacement (pp) of the vibrated part 110 in the example ultrasonic vibration device 100. As the thickness of the adhesive layer 130 increased from 70 μm to 100 μm, the difference between the displacement (pp) of the vibrated part 110 in the comparative ultrasonic vibration device 900 and the displacement (pp) of the vibrated part 110 in the example ultrasonic vibration device 100 increased. When the thickness of the adhesive layer 130 was 100 μm, the displacement (pp) of the vibrated part 110 in the example ultrasonic vibration device 100 was 1.5 times that of the vibrated part 110 in the comparative ultrasonic vibration device 900.

[0027] The mechanism by which the displacement amount (pp) of the vibrated part 110 in the ultrasonic vibration device 100 according to the embodiment is larger than the displacement amount (pp) of the vibrated part 110 in the ultrasonic vibration device 900 according to the comparative example will be explained.

[0028] In the ultrasonic vibration device 100 according to the embodiment, the piezoelectric element 121 is sandwiched between a first resin layer 125 and a second resin layer 126. This reduces the overall spring constant of the transducer 120 and increases the displacement (pp) of the transducer 120 alone. Specifically, since the Young's moduli of the first resin layer 125 and the second resin layer 126 are smaller than those of the first metal layer 127 and the second metal layer 128, the interposition of the first resin layer 125 between the piezoelectric element 121 and the first metal layer 127, and the interposition of the second resin layer 126 between the piezoelectric element 121 and the second metal layer 128, reduces the deformation resistance of the piezoelectric element 121 in the thickness direction (Z-axis direction), and increases the displacement of the piezoelectric element 121 in the thickness direction (Z-axis direction).

[0029] Furthermore, the piezoelectric element 121 expands and contracts in the in-plane direction (XY in-plane direction). This expansion and contraction is converted into displacement in the thickness direction (Z axis direction) in the first resin layer 125 and the second resin layer 126, according to the Poisson's ratio of the resins constituting the first resin layer 125 and the second resin layer 126, and is added to the displacement of the piezoelectric element 121 in the thickness direction (Z axis direction). As a result, in the ultrasonic vibration device 100 according to the embodiment, the transducer 120 vibrates in a thickness longitudinal vibration mode, expanding and contracting in the thickness direction (Z axis direction). Therefore, even if the thickness of the adhesive layer 130 increases to about 100 μm, the attenuation of vibrations transmitted from the transducer 120 to the vibrated part 110 is suppressed. Thus, in the ultrasonic vibration device 100 according to the embodiment, the effect of the thickness of the adhesive layer 130 is mitigated, and the vibrated part 110 can be stably displaced significantly.

[0030] On the other hand, in the ultrasonic vibration device 900 according to the comparative example, a piezoelectric element 121 is bonded to the vibrated part 110 by an adhesive layer 130 to form a unimorph structure, and the vibrated part 110 is vibrated in a bending vibration mode. Therefore, when the thickness of the adhesive layer 130 increases to about 100 μm, the restraining force between the vibrated part 110 and the transducer 120 weakens, and the efficiency of converting the expansion and contraction of the piezoelectric element 121 in the in-plane direction (XY in-plane direction) into bending vibration decreases. Thus, in the ultrasonic vibration device 900 according to the comparative example, the thickness of the adhesive layer 130 has a significant effect, and it is not possible to stably displace the vibrated part 110 significantly.

[0031] Figure 6 is a graph showing the measured relationship between the vibration frequency of the vibrated part and the impedance of the transducer in the ultrasonic vibration apparatus according to the example and comparative example. In Figure 6, the vertical axis shows the impedance of the transducer (Ω), and the horizontal axis shows the vibration frequency of the vibrated part 110 (kHz). The data for the ultrasonic vibration apparatus 100 according to the example is shown by a solid line, and the data for the ultrasonic vibration apparatus 900 according to the comparative example is shown by a dotted line.

[0032] For the experimental conditions, the driving voltage applied to the transducer 120 was set to 100 Vp-p. However, during impedance measurement, the driving voltage applied to the transducer 120 was set to 0.5 Vrms. The resonance frequency of the first mode of the transducer 120 alone was set to 130 kHz. The adhesive layer 130 consisted of a copper foil tape with a thickness of 60 μm and epoxy adhesive. The vibrated part 110 was a glass plate with a thickness of 2 mm.

[0033] As shown in Figure 6, in both the ultrasonic vibration device 100 according to the embodiment and the ultrasonic vibration device 900 according to the comparative example, multiple frequencies appear where the impedance of the transducer has its lowest peak, and the vibrated part 110 resonates at each of these frequencies. Hereinafter, the desired frequency at which the vibrated part 110 is made to resonate will be referred to as the target resonance frequency.

[0034] Of the multiple resonant frequencies shown in Figure 6, the target resonant frequency at which the vibrated part 110 is vibrated was set to 70 kHz for the ultrasonic vibration device 100 according to the example and to 71.25 kHz for the ultrasonic vibration device 900 according to the comparative example. Calculating the displacement of the vibrated part 110 using the relationship v / 2πf, the displacement (pp) of the vibrated part 110 in the ultrasonic vibration device 900 according to the comparative example was 1.6 μm, while the displacement (pp) of the vibrated part 110 in the ultrasonic vibration device 100 according to the example was 2.3 μm. In other words, the displacement (pp) of the vibrated part 110 in the ultrasonic vibration device 100 according to the example was 1.4 times that of the vibrated part 110 in the ultrasonic vibration device 900 according to the comparative example.

[0035] Here, a method for configuring the transducer 120 to achieve the target resonant frequency in an ultrasonic vibration device 100 according to one embodiment of the present invention will be described. Figure 7 is a graph schematically showing the relationship between the target resonant frequency and the impedance of the transducer. In Figure 7, the impedance of the transducer (Ω) is shown on the vertical axis and the frequency (kHz) is shown on the horizontal axis. The data for the transducer 120 alone is shown by a solid line, and the data for the transducer 120 attached to the vibrated part 110 is shown by a dotted line.

[0036] As shown in Figure 7, for the oscillator 120 alone, the frequency Fx at which the impedance reaches its lowest peak is the resonance frequency of the first mode. The configuration of the oscillator 120 is set so that the impedance of the oscillator 120 bonded to the vibrated part 110 reaches its lowest peak at the target resonance frequency Fy. Specifically, the thicknesses of the first resin layer 125, the second resin layer 126, the first metal layer 127, and the second metal layer 128, as well as the Young's modulus, density, and Poisson's ratio that the materials constituting the first resin layer 125, the second resin layer 126, the first metal layer 127, and the second metal layer 128 should have, are set so that the impedance of the oscillator 120 bonded to the vibrated part 110 reaches its lowest peak at the target resonance frequency Fy.

[0037] As described above, in the ultrasonic vibration device 100 according to one embodiment of the present invention, the vibrated part 110 is vibrated at a target resonant frequency Fy in the resonance mode of the thickness longitudinal vibration mode. The resonant frequency Fx of the first mode of at least one transducer 120 is equal to or greater than the target resonant frequency Fy. That is, the resonant frequency Fx of the first mode of at least one transducer 120 may be higher than the target resonant frequency Fy, or it may be the same as the target resonant frequency Fy. This suppresses the excitation of unwanted resonant modes of the transducer 120, so that the vibrated part 110 can be displaced uniformly in the plane.

[0038] When the ultrasonic vibration device 100 according to one embodiment of the present invention is used as a haptic device, it is preferable that the internode distance of the standing wave W is 8 mm or less and the target resonant frequency Fy is 70 kHz or higher in order to obtain uniform tactile feedback over the entire surface of the vibrated part 110.

[0039] Here, we will explain the results of a simulation analysis of the relationship between the Poisson's ratio of the resins constituting the first resin layer 125 and the second resin layer 126, and the displacement (Peak to Peak) of the vibrated part 110.

[0040] Figure 8 is a graph showing the results of a simulation analysis of the relationship between the Poisson's ratio of the resins constituting a pair of resin layers and the displacement of the vibrated part in the ultrasonic vibration device according to the embodiment. In Figure 8, the vertical axis shows the displacement (Peak to Peak) (μm) of the vibrated part 110, and the horizontal axis shows the Poisson's ratio of the resins constituting the first resin layer 125 and the second resin layer 126, respectively. The data for the ultrasonic vibration device 100 according to the embodiment is shown as a solid line, and the data for the ultrasonic vibration device 900 according to the comparative example is shown as a dotted line. As an analysis condition, the thickness of the adhesive layer 130 was set to 60 μm in both the ultrasonic vibration device 100 according to the embodiment and the ultrasonic vibration device 900 according to the comparative example.

[0041] As shown in Figure 8, the displacement (pp) of the vibrated part 110 in the ultrasonic vibration device 100 according to the embodiment increased as the Poisson's ratio of the resins constituting the first resin layer 125 and the second resin layer 126 increased. In the range where the Poisson's ratio of the resins constituting the first resin layer 125 and the second resin layer 126 is 0.25 or higher, the displacement (pp) of the vibrated part 110 in the ultrasonic vibration device 100 according to the embodiment was greater than the displacement (pp) of the vibrated part 110 in the ultrasonic vibration device 900 according to the comparative example. When the Poisson's ratio of the resins constituting the first resin layer 125 and the second resin layer 126 is 0.3 or higher, the difference between the displacement (pp) of the vibrated part 110 in the ultrasonic vibration device 900 according to the comparative example and the displacement (pp) of the vibrated part 110 in the ultrasonic vibration device 100 according to the embodiment increased.

[0042] FIG. 9 is a plan view showing an ultrasonic vibration device according to a modification of an embodiment of the present invention. As shown in FIG. 9, in an ultrasonic vibration device 100a according to a modification of an embodiment of the present invention, a plurality of vibrators 120 are arranged at both ends in the lateral direction (X-axis direction) of the vibrating portion 110 so as to be arranged in a plurality of rows at intervals in the longitudinal direction (Y-axis direction). In this modification, the plurality of vibrators 120 are arranged in two rows at both ends in the lateral direction (X-axis direction) of the vibrating portion 110, but may be three or more rows.

[0043] Also in this modification, the plurality of vibrators 120 are arranged so as to be located at the antinode positions of the standing wave W caused by the vibration of the vibrating portion 110 in the above resonance mode. Specifically, the plurality of vibrators 120 are arranged such that the centers of each of the plurality of vibrators 120 arranged in a plurality of rows are located at the antinode positions of the standing wave Wx and at the antinode positions of the standing wave Wy. Thereby, the displacement of the vibration of the vibrating portion 110 in the above resonance mode can be increased.

[0044] (Supplementary Note) It is understood by those skilled in the art that the above-described exemplary embodiments are specific examples of the following aspects.

[0045] <1> An ultrasonic vibration device comprising a vibrating portion and at least one vibrator adhered to the vibrating portion to vibrate the vibrating portion, wherein the at least one vibrator includes a piezoelectric element, a pair of resin layers sandwiching the piezoelectric element therebetween, and a pair of metal layers sandwiching the piezoelectric element and the pair of resin layers therebetween, and the at least one vibrator vibrates the vibrating portion in a resonance mode.

[0046] <2> The ultrasonic vibration device according to <1>, wherein the vibrating portion is vibrated at a target resonance frequency in the resonance mode, and the resonance frequency of the primary mode of the at least one vibrator is not less than the target resonance frequency.

[0047] <3> The ultrasonic vibration device according to <2>, wherein the target resonance frequency is 70 kHz or more.

[0048] <4> The Poisson's ratio of the resin constituting each of the pair of resin layers is 0.3 or more. The ultrasonic vibration device according to any one of <1> to <3>.

[0049] <5> In the pair of metal layers, the other metal layer is thicker than the one metal layer adhered to the vibrating portion. The ultrasonic vibration device according to any one of <1> to <4>.

[0050] <6> The maximum length of the at least one vibrator in a direction orthogonal to the stacking direction of the at least one vibrator is equal to or less than the wavelength of the flexural vibration of the at least one vibrator. The ultrasonic vibration device according to any one of <1> to <5>.

[0051] <7> A plurality of the at least one vibrator are arranged so as to be located at the position of the antinode of the standing wave due to the vibration of the vibrating portion in the resonance mode. The ultrasonic vibration device according to any one of <1> to <6>.

[0052] In the description of the above-described embodiment, configurations that can be combined may be combined with each other.

[0053] The embodiments and examples disclosed this time should be considered as illustrative in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

[0054] 100, 100a, 900 Ultrasonic vibration device, 110 Vibrating portion, 120 Vibrator, 121 Piezoelectric element, 122 Piezoelectric body, 123 First electrode layer, 124 Second electrode layer, 125 First resin layer, 126 Second resin layer, 127 First metal layer, 128 Second metal layer, 130 Adhesive layer, Fx Resonance frequency, Fy Target resonance frequency, W, Wx, Wy Standing wave.

Claims

1. An ultrasonic vibration device comprising a part to be vibrated and at least one vibrator bonded to the part to be vibrated and causing the part to be vibrated, wherein the at least one vibrator is constructed by laminating a piezoelectric element, a pair of resin layers sandwiching the piezoelectric element between each other, and a pair of metal layers sandwiching the piezoelectric element and the pair of resin layers between each other, and the at least one vibrator causes the part to be vibrated in a resonant mode.

2. The ultrasonic vibration device according to claim 1, wherein the part to be vibrated is vibrated at a target resonant frequency in the resonant mode, and the resonant frequency of the primary mode of at least one transducer is equal to or greater than the target resonant frequency.

3. The ultrasonic vibration device according to claim 2, wherein the target resonant frequency is 70 kHz or higher.

4. The ultrasonic vibration device according to any one of claims 1 to 3, wherein the Poisson's ratio of the resin constituting each of the pair of resin layers is 0.3 or more.

5. The ultrasonic vibration apparatus according to any one of claims 1 to 4, wherein in the pair of metal layers, the other metal layer is thicker than the metal layer bonded to the part that is vibrated.

6. The ultrasonic vibration apparatus according to any one of claims 1 to 5, wherein the maximum length of the at least one transducer in a direction perpendicular to the stacking direction of the at least one transducer is less than or equal to the wavelength of the bending vibration of the at least one transducer.

7. The ultrasonic vibration device according to any one of claims 1 to 6, wherein the at least one transducer is arranged in such a manner that it is positioned at the antinodes of standing waves resulting from vibrations in the resonant mode of the part being vibrated.

Images