Vibration generating device and tactile sense generating device

Abstract

The vibration generating device includes: piezoelectric elements (10a, 10b) including a piezoelectric layer, and a first electrode and a second electrode sandwiching the piezoelectric layer, the piezoelectric elements being capable of expanding and contracting in a direction in which the piezoelectric layer is sandwiched between the first electrode and the second electrode by applying a voltage between the first electrode and the second electrode; and a housing 25 including a first member 30 and a second member 20 that sandwich the piezoelectric element in the direction, the first member and the second member being capable of pressing the piezoelectric element in the direction, the first member being capable of outputting sound waves in the direction in accordance with expansion and contraction of the piezoelectric element.

Description

Technical Field

[0001] The invention relates to a vibration generating device and a tactile generating device. Background Art

[0002] It is known that a piezoelectric element is used in a vibration generating device such as a transducer that converts an electrical signal into an acoustic wave. It is known that a Langevin type vibrator having a vibration plate is used to generate ultrasonic waves.

[0003] In addition, it is known that a vibrator of a tactile sense generating device that generates a tactile sense by vibration of the vibrator generates vibration of a modulated wave modulated by a rectangular wave (for example, Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 8-314369 Summary of the invention

[0007] Technical problem to be solved by the invention

[0008] In the case where the vibration generating device has a vibration plate, when the vibration plate is reduced in size, the output will decrease. In a structure without a vibration plate, although miniaturization can be achieved, it is difficult to achieve high output. As described above, it is difficult to achieve both miniaturization and high output of the vibration generating device.

[0009] Alternatively, for a tactile sense generating device, a hard material is required to exhibit a soft tactile sense.

[0010] The present invention has been made in view of the above-mentioned technical problems, and an object of the present invention is to achieve miniaturization and high output, or to provide a soft touch.

[0011] Means for solving technical problems

[0012] The present invention is a vibration generating device, comprising: a piezoelectric element, comprising a piezoelectric layer and a first electrode and a second electrode sandwiching the piezoelectric layer, wherein the piezoelectric element can expand and contract in a direction in which the first electrode and the second electrode sandwich the piezoelectric layer by applying a voltage between the first electrode and the second electrode; and a shell, comprising a first component and a second component sandwiching the piezoelectric element in the direction, wherein the first component and the second component can press the piezoelectric element in the direction, and the first component can output a sound wave corresponding to the expansion and contraction of the piezoelectric element in the direction.

[0013] In the above configuration, the first member and the second member may be configured so as to be able to press the piezoelectric element by fitting a thread provided on the first member with a thread provided on the second member.

[0014] In the above structure, it can be constructed to include a third component joined to the first component and the second component, and the first component and the second component can press the piezoelectric element by making the thread teeth set on the first component engage with the thread teeth set on the third component, and making the thread teeth set on the second component engage with the thread teeth set on the third component.

[0015] In the above structure, it can be constructed to include at least one of a fourth component and a fifth component, wherein the fourth component is arranged between the first component and the piezoelectric element and has a Young's modulus larger than the Young's modulus of the first component and the Young's modulus of the piezoelectric layer, and the fifth component is arranged between the second component and the piezoelectric element and has a Young's modulus larger than the Young's modulus of the second component and the Young's modulus of the piezoelectric layer.

[0016] In the above structure, the pressure of the first member and the second member pressing the piezoelectric element may be 5×10 5 Pa or above.

[0017] In the above structure, it can be constructed that the piezoelectric layer, the first electrode and the second electrode are respectively provided in plurality, the plurality of first electrodes and the plurality of second electrodes are alternately arranged in the direction, and one piezoelectric layer among the plurality of piezoelectric layers is sandwiched by one of the plurality of first electrodes and one of the plurality of second electrodes in the direction.

[0018] In the above structure, it can be constructed that the first component can output the sound wave to the space in the direction, and can supply a modulated wave as the voltage to the piezoelectric element, and the modulated wave is obtained by amplitude modulating a carrier having a frequency greater than 0.86 times and less than 1.14 times the resonant frequency of the shell using a signal wave having a frequency lower than the frequency of the carrier.

[0019] In the above configuration, the frequency of the signal wave may be greater than or equal to 70 Hz and less than or equal to 1000 Hz.

[0020] In the above structure, it can be constructed that the first component is capable of outputting the sound wave to the space in the direction, and is capable of supplying the piezoelectric element with a second modulated wave as the voltage, which is obtained by amplitude modulating a first carrier wave having a frequency greater than 0.86 times and less than 1.14 times the resonant frequency of the shell using a first modulation wave, wherein the first modulation wave is obtained by amplitude modulating a second carrier wave having a frequency greater than 50 Hz and less than 300 Hz using a signal wave having a frequency greater than 1 Hz and less than 60 Hz.

[0021] In the above configuration, a central portion of a surface of the first member on the space side may be recessed toward the piezoelectric element.

[0022] The above configuration may include a driving device capable of supplying the modulated wave as the voltage to the piezoelectric element.

[0023] In the above configuration, the voltage may be supplied to the piezoelectric element so that the surface of the first member in the direction is pressed against a pressed member, thereby generating an acoustic wave from the pressed member.

[0024] The above structure may include: a biasing member capable of biasing the surface of the first member against the biased member; and a driving device capable of supplying the voltage to the piezoelectric element.

[0025] The present invention is a tactile generating device, comprising: a vibrator; and a driving device, which is capable of amplitude modulating a carrier having a frequency greater than 0.86 times and less than 1.14 times the resonant frequency of the vibrator using a signal wave having a frequency greater than 1 Hz and less than 60 Hz lower than the frequency of the carrier and being a rectangular wave, thereby generating a modulated wave having a modulation degree greater than 50% and less than 100%, and supplying the modulated wave to the vibrator.

[0026] In the above structure, it can be constructed that the vibrator includes: a piezoelectric element, which includes a piezoelectric layer and a first electrode and a second electrode sandwiching the piezoelectric layer, by applying a voltage between the first electrode and the second electrode, the piezoelectric element can expand and contract in the direction in which the first electrode and the second electrode sandwich the piezoelectric layer; and a shell, which includes a first component and a second component sandwiching the piezoelectric element in the direction, the first component and the second component can press the piezoelectric element in the direction and output vibrations corresponding to the expansion and contraction of the piezoelectric element.

[0027] In the above configuration, the first member and the second member may be configured to be able to press the piezoelectric element by threading the first member and the second member.

[0028] In the above structure, it can be constructed to include at least one of a third component and a fourth component, wherein the third component is arranged between the first component and the piezoelectric element and has a Young's modulus larger than the Young's modulus of the first component and the Young's modulus of the piezoelectric layer, and the fourth component is arranged between the second component and the piezoelectric element and has a Young's modulus larger than the Young's modulus of the second component and the Young's modulus of the piezoelectric layer.

[0029] In the above structure, the pressure of the first member and the second member pressing the piezoelectric element may be 5×10 5 Pa or above.

[0030] In the above structure, it can be constructed that the piezoelectric layer, the first electrode and the second electrode are respectively provided in plurality, the plurality of first electrodes and the plurality of second electrodes are alternately arranged in the direction, and one piezoelectric layer among the plurality of piezoelectric layers is sandwiched by one of the plurality of first electrodes and one of the plurality of second electrodes in the direction.

[0031] In the above structure, the structure may include a member that contacts with at least a portion of the housing, can transmit vibration from the at least a portion, and is softer than the at least a portion.

[0032] In the above configuration, the degree of modulation may be 98% or less.

[0033] In the above structure, the frequency of the signal wave is greater than or equal to 3 Hz and less than or equal to 50 Hz.

[0034] Effects of the Invention

[0035] According to the present invention, it is possible to achieve miniaturization and high output, or to provide a soft touch. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 (a) is a plan view of the vibration generating element of Example 1, Figure 1 (b) is Figure 1 AA cross-section view of (a).

[0037] Figure 2 (a) is a plan view of the second component in Example 1, Figure 2 (b) is Figure 2 (a) AA cross-section view, Figure 2 (c) is a cross-sectional view of the first component.

[0038] Figure 3 This is a cross-sectional view of the piezoelectric element in Example 1.

[0039] Figure 4 It is a schematic diagram of the vibration generating device of Example 2.

[0040] Figure 5 This is a diagram showing the modulated wave supplied by the driving device to the piezoelectric element in Example 2.

[0041] Figure 6 (a) and Figure 6 (b) is a cross-sectional view of the second component in Experiment 1.

[0042] Figure 7 This is a diagram showing a modulated wave supplied by a driving device to a piezoelectric element in a first variation of the second embodiment.

[0043] Figure 8 It is a schematic diagram of a vibration generating device of variant example 2 of embodiment 2.

[0044] Fig. 9 It is a schematic diagram of the vibration generating device of Example 3.

[0045] Fig.10 (a) is a plan view of the pushing component in Example 3, Fig.10 (b) is Fig.10 AA cross-section view of (a).

[0046] Fig.11 This is a cross-sectional view of the vibration generating element of Example 4.

[0047] Fig.12 It is a schematic diagram of a vibration generating device of variant example 1 of embodiment 4.

[0048] Fig.13 This is a graph showing the amplitude relative to Vp-p in Experiment 2.

[0049] Fig.14 It is a schematic diagram of a vibration generating device of variant example 3 of embodiment 4.

[0050] Fig.15 It is a schematic diagram of the tactile generating device of Example 5.

[0051] Fig.16 (a) is a plan view of the vibrator in Example 5, Fig.16 (b) is Fig.16 AA cross-section view of (a).

[0052] Fig.17 (a) is a plan view of the second part of the vibrator in Example 6, Fig.17 (b) is Fig.17 (a) AA cross-section view, Fig.17 (c) is a cross-sectional view of the first component.

[0053] Fig.18 This is a cross-sectional view of the piezoelectric element in Example 5.

[0054] Fig.19 This is a diagram showing the modulated wave supplied by the driving device to the piezoelectric element in Example 5.

[0055] Fig. 20 (a) and Fig. 20 (b) is a cross-sectional view showing another example of the second component in Example 5.

[0056] Fig.21 It is a schematic diagram of a tactile sensation generating device according to variant example 1 of embodiment 5.

[0057] Fig. 22 (a) is a cross-sectional view of the first part of the vibrator in Example 6, Fig. 22 (b) is a cross-sectional view of the second component of the vibrator in Example 6.

[0058] Fig.23 It is a schematic diagram of the tactile generating device in Example 7.

[0059] Fig.24 (a) is a plan view of the tactile sensation generating device in Example 8, Fig.24 (b) is Fig.24 AA cross-section view of (a).

[0060] Fig.25 This is a cross-sectional view of the vibrator in Example 8. DETAILED DESCRIPTION

[0061] Hereinafter, embodiments will be described with reference to the accompanying drawings.

[0062] Example 1

[0063] By improving the Q value (Quality Factor) characteristics of the mechanical vibration of the vibrator, it is possible to achieve a higher output of the vibration generating device even without using a vibration plate. In the first embodiment, a vibration generating device capable of improving the Q value of the mechanical vibration of the housing is described.

[0064] Figure 1 (a) is a plan view of the vibration generating element of Example 1, Figure 1 (b) is Figure 1 AA cross-section view of (a). Figure 2 (a) is a plan view of the second component in Example 1, Figure 2 (b) is Figure 2 (a) AA cross-section view, Figure 2(c) is a cross-sectional view of the first member. The direction in which the first member 30 and the second member 20 sandwich the piezoelectric elements 10a and 10b is defined as the Z direction, and the directions in which the sides of the piezoelectric elements 10a and 10b extending in a plan view are orthogonal to the Z direction as the X direction and the Y direction.

[0065] like Figure 1 (a) to Figure 2 As shown in (c), in the vibration generating element 100 of Example 1, the shell 25 includes a first component 30 and a second component 20. The first component 30 is joined to the second component 20. A recess 28 is provided on the surface of the second component 20 in the +Z direction. The recess 28 has a first part 22 provided on the +Z side and a second part 24 provided on the -Z side. The planar shape of the first part 22 is a substantially circular shape, and the planar shape of the second part 24 is a substantially rectangular shape. A thread 26 forming an internal thread is formed on the side surface of the first part 22. No thread is formed on the side surface of the second part 24. In the recess 28, the support component 12a, the piezoelectric elements 10a, 10b and the support component 12b are inserted in sequence from the -Z side. The support component 12a, the piezoelectric elements 10a, 10b and the support component 12b are not joined to the second component 20 and are movable.

[0066] The first component 30 includes a head 32 provided on the +Z side and a threaded portion 34 provided on the -Z side. The planar shape of the head 32 is substantially circular. The central portion of the surface on the +Z side of the head 32 is recessed in an inverted cone shape relative to the peripheral portion in the -Z direction. A thread 36 forming an external thread is formed on the side surface of the threaded portion 34. The threaded portion 34 of the first component 30 can be engaged with the first portion 22 of the recess 28 of the second component 20 by fitting the thread 26 with the thread 36. By tightening the thread, the second component 20 can press the piezoelectric element 10a in the +Z direction as indicated by the arrow 50a via the support component 12a. The first component 30 can press the piezoelectric element 10b in the -Z direction as indicated by the arrow 50b via the support component 12b. The stress pressing the piezoelectric elements 10a and 10b is, for example, 5×10 6 Pa or above.

[0067] The material of the first member 30 and the second member 20 is, for example, metal or resin. The material of the supporting members 12a and 12b is a material having a Young's modulus greater than that of the first member 30, the second member 20, and the piezoelectric elements 10a and 10b, such as stainless steel or aluminum. The width of the head 32 of the first member 30 in the X direction and the Y direction is 10 mm as an example, the height of the head 32 in the Z direction is 2.5 mm as an example, the amount of depression of the top of the inverted cone of the +Z surface of the head 32 is 1.5 mm as an example, the width of the threaded portion 34 in the X direction and the Y direction is 6 mm as an example, and the height of the threaded portion 34 in the Z direction is 5 mm as an example.

[0068] The width of the second member 20 in the X and Y directions is 8 mm as an example, the height is 15 mm as an example, the depth of the recess 28 in the Z direction is 14 mm as an example, the depth of the first portion 22 in the Z direction is 6 mm as an example, and the width of the second portion 24 in the X and Y directions is 4.5 mm as an example. The materials, shapes, and sizes of the first member 30, the second member 20, and the supporting members 12a and 12b can be appropriately designed.

[0069] Figure 3 is a cross-sectional view of the piezoelectric element in Example 1. Figure 3 As shown, the piezoelectric elements 10a and 10b include a piezoelectric body 40 composed of a plurality of piezoelectric layers 41, a plurality of first electrodes 42, and a plurality of second electrodes 44. The plurality of piezoelectric layers 41 are stacked in the Z direction. The piezoelectric layer 41, the first electrode 42, and the second electrode 44 are in the shape of a flat plate extending in the XY plane. The plurality of first electrodes 42 and the plurality of second electrodes 44 are arranged alternately in the Z direction. One piezoelectric layer 41 is sandwiched by one first electrode 42 and one second electrode 44 in the Z direction. A first external electrode 43 is arranged on the side surface of the -X side of the piezoelectric body 40, and a second external electrode 45 is arranged on the side surface of the +X side of the piezoelectric body 40. The plurality of first electrodes 42 are electrically connected to the first external electrode 43. The plurality of second electrodes 44 are electrically connected to the second external electrode 45. By applying a voltage between the first external electrode 43 and the second external electrode 45, the piezoelectric body 40 can expand and contract in the Z direction as shown by the arrow 52 by utilizing the inverse piezoelectric effect. The vibration mode in which the first electrode 42 and the second electrode 44 expand and contract in the stacking direction by applying a voltage to the first electrode 42 and the second electrode 44 is referred to as a longitudinal displacement mode or a d33 mode.

[0070] The piezoelectric body 40 includes a first region 46, a second region 47, and a third region 48. The first region 46 and the second region 47 are alternately arranged in the Z direction. The third region 48 is arranged outside the outermost first region 46 in the Z direction. The first region 46 is a region where the first electrode 42 and the second electrode 44 are alternately arranged at a certain interval in the Z direction. As an example, the number of stacking layers of the piezoelectric layer 41 in the first region 46 is 50 layers. The second region 47 and the third region 48 are regions where the first electrode 42 and the second electrode 44 are not arranged. The second region 47 may not be arranged. There is also a case where reliability is improved by setting the second region 47.

[0071] As the material of the piezoelectric layer 41, for example, lead zirconate titanate (PZT: Pb(Zr, Ti)O3), barium titanate materials (BaTiO3, Ba can also be Ca, Ti can also be Zr), bismuth titanate materials (BiTiO3, part of Bi can also be Na), niobate alkali materials (NaNbO3, Na can also be Li or K) can be used. As the material of the first electrode 42, the second electrode 44, the first external electrode 43 and the second external electrode 45, for example, metals such as Ag, Pd, Pt, Cu, Ni and Au can be used. The piezoelectric elements 10a and 10b are sheets composed of a sintered body formed by stacking and sintering piezoelectric sheets having the first electrode 42 and the second electrode 44 formed on the surface. The piezoelectric elements 10a and 10b are, for example, rectangular parallelepipeds, and the widths of the piezoelectric elements 10a and 10b in the X direction and the Y direction are, as an example, 3.5 mm, and the heights in the Z direction are, as an example, 3 mm.

[0072] When the displacement in the Z direction of the surface on the ±Z side of the piezoelectric elements 10a and 10b is ΔZ, the number of stacked piezoelectric layers 41 is N, the voltage applied between the first electrode 42 and the second electrode 44 is V, and the constant related to the inverse piezoelectric constant is d33, ΔZ=d33×V×N. Therefore, by increasing the number of stacked layers N of the piezoelectric layer 41, the displacement ΔZ becomes larger. However, due to manufacturing constraints, etc., there are cases where the number of stacked layers N in one piezoelectric element 10a or 10b cannot be increased. In such a case, the piezoelectric elements 10a and 10b can be stacked in the Z direction within the housing 25. Thereby, the total displacement of the piezoelectric elements 10a and 10b can be increased. The number of piezoelectric elements 10a and 10b stacked in the Z direction can be one or more than three.

[0073] By pressing the piezoelectric elements 10a and 10b by the housing 25, the Q value is improved compared to the case where the housing 25 does not press the piezoelectric elements 10a and 10b. Such a phenomenon cannot be obtained when using piezoelectric elements of a lateral displacement mode as the piezoelectric elements 10a and 10b, and is a phenomenon discovered for the first time by the inventor of the present invention. In addition, the lateral displacement mode refers to a mode in which the vibration direction of the piezoelectric elements 10a and 10b is orthogonal to the stacking direction of the first electrode 42 and the second electrode 44. The resonant frequency does not change much with respect to the presence or absence of the pressing of the piezoelectric elements 10a and 10b. It can be considered that this is because the supporting member 12a is provided.

[0074] According to Example 1, using Figure 3 In this way, the piezoelectric layer 41 is sandwiched between the first electrode 42 and the second electrode 44 in the Z direction, and the piezoelectric elements 10a and 10b can be expanded and contracted in the Z direction by applying a voltage between the first electrode 42 and the second electrode 44. Figure 1 As shown in (b), the first component 30 and the second component 20 can press the piezoelectric element 10a in the Z direction, and the first component 30 can output sound waves corresponding to the expansion and contraction of the piezoelectric elements 10a and 10b in the Z direction. As described above, by pressing the longitudinal displacement type piezoelectric elements 10a and 10b by the housing 25, the Q value of the mechanical vibration of the housing 25 is improved. Therefore, even in a small vibration generating device without a vibration plate, high output can be achieved.

[0075] The first component 30 and the second component 20 can press the piezoelectric elements 10a and 10b by fitting the thread teeth 26 and the thread teeth 36. As a result, the piezoelectric elements 10a and 10b can be pressed stably with a large force. In addition, the deviation of the pressure applied to the piezoelectric elements 10a and 10b can be suppressed. Therefore, the deviation of the resonant frequency can be suppressed. As an example, when a plurality of structures are made, the deviation of the resonant frequency is less than 600 Hz. The mechanism for pressing the piezoelectric elements 10a and 10b may also be a mechanism other than the fitting of the threads.

[0076] In Example 1, when the nominal diameter d (maximum diameter) of the thread 36 of the first component 30 is 6 mm, when the tightening torque T of the first component 30 is measured using a torque wrench, it is approximately 0.1 N·m. The force F of the first component 30 pressing the piezoelectric element 10b is T / (k×d), and when the torque coefficient k is 0.2, F=83N. The area of ​​the XY plane of the piezoelectric elements 10a and 10b is 3.5 mm×3.5 mm. Therefore, the pressure of the first component 30 pressing the piezoelectric element 10b is 6.8×10 6 Pa. It is believed that the effect of improving the Q value of the mechanical vibration of the housing 25 is effective even at a pressure of 6.8×10 6Therefore, the pressure of the first component 30 and the second component 20 pressing the piezoelectric elements 10a and 10b is preferably 5×10 5 Pa or more, more preferably 1×10 6 Pa or more, more preferably 2×10 6 The pressure at which the first member 30 and the second member 20 press the piezoelectric elements 10a and 10b is equal to or lower than the pressure at which the piezoelectric elements 10a and 10b are destroyed.

[0077] A supporting member 12b (fourth member) is provided between the first member 30 and the piezoelectric element 10b, and a supporting member 12a (fifth member) is provided between the second member 20 and the piezoelectric element 10a. It is sufficient to provide at least one of the supporting members 12a and 12b. When PZT is used as the piezoelectric body 40, the Young's modulus of PZT is approximately 60 GPa. When a resin is used as the housing 25, the Young's modulus of the resin is less than 10 GPa. When stainless steel is used as the supporting members 12a and 12b, the Young's modulus of stainless steel is approximately 120 GPa. In addition, the Young's modulus of aluminum is approximately 70 GPa. As described above, the Young's modulus of the supporting member 12b is greater than the Young's modulus of the piezoelectric body 40 and the Young's modulus of the first member 30, and the Young's modulus of the supporting member 12b is greater than the Young's modulus of the piezoelectric body 40 and the Young's modulus of the second member 20. By providing the support members 12a and 12b, a load can be applied to the piezoelectric elements 10a and 10b, thereby strengthening the transmission of vibration. Therefore, the resonance frequency of the housing 25 can be suppressed from changing due to pressure, and the Q value can be further improved. It is sufficient to provide at least one of the support members 12a and 12b. The Young's modulus of the support members 12b and 12a is preferably 1.2 times or more of the Young's modulus of the piezoelectric body 40 and the Young's modulus of each of the first member 30 and the second member 20, and more preferably 1.5 times or more.

[0078] like Figure 3 As shown, in the piezoelectric elements 10a and 10b, the plurality of first electrodes 42 and the plurality of second electrodes 44 are alternately arranged in the Z direction, and one of the plurality of piezoelectric layers 41 is sandwiched in the Z direction by one of the plurality of first electrodes 42 and one of the plurality of second electrodes 44. With such a structure, the displacement in the Z direction can be further increased, and the characteristics of the vibration generating device can be further improved.

[0079] Example 2

[0080] Embodiment 2 is an example in which the vibration generating element 100 of Embodiment 1 is used in a vibration generating device for spatial tactile sensation. Figure 4 It is a schematic diagram of the vibration generating device of Example 2.

[0081] like Figure 4 As shown, in the vibration generating device 101 of Example 2, the housing 25 of the vibration generating element 100 of Example 1 is fixed on the base 60. The base 60 has rigidity like a metal plate. The driving device 62 can supply voltage between the first external electrode 43 and the second external electrode 45 of the piezoelectric elements 10a and 10b in the housing 25. The sound wave 54 can be emitted from the first component 30 in the Z direction. When a part of the human body (such as a finger or a palm) is suspended in the +Z direction of the first component 30, a sense of touch can be obtained through the sound wave 54.

[0082] Figure 5 This is a diagram showing the modulated wave supplied by the driving device to the piezoelectric element in Example 2. Figure 5 The horizontal axis represents time, and the vertical axis represents voltage. Figure 5 As shown in FIG. 6 , a signal with a period of T1 (frequency f1) is a carrier wave 64. An envelope 65 of a modulated wave 66 corresponds to a signal wave. The signal wave has a period of T2 (frequency f2). A sine wave is used as the carrier wave 64, but a triangular wave is shown as the carrier wave 64 for the sake of simplicity. In addition, the period T1 is much smaller than the period T2, but for the sake of easy understanding, the period T1 is shown in FIG. Figure 5 The period T1 is magnified in the figure. In the modulated wave 66, the carrier wave 64 is amplitude modulated by the signal wave. Figure 5 In the example, the carrier wave 64 and the signal wave are both sine waves. The signal wave may also be a rectangular wave, a triangular wave, or a sawtooth wave other than a sine wave.

[0083] The frequency f1 of the carrier wave 64 is, for example, the resonant frequency of the housing 25. The resonant frequency may be a fundamental wave or a higher harmonic. The frequency f2 of the signal wave is a frequency that the Pacinian corpuscles, which are receptors of the human skin, can sensitively sense. Such a frequency is, for example, 70 Hz or more and 1000 Hz or less. The frequency that the Pacinian corpuscles, etc. can sensitively sense is 250 Hz.

[0084] When the maximum amplitude of the envelope 65 in the modulated wave 66 is A1 and the minimum amplitude of the envelope is A2, the modulation degree M is defined as M=(A1-A2) / (A1+A2). The modulation degree M of the modulated wave 66 is, for example, 50% or more and 100% or less, preferably 80% or more and 100% or less.

[0085] [Experiment 1]

[0086] The shape of the second member 20 was changed to investigate the tactile sensation in mid-air.

[0087] The materials of the components used in the experiments are as follows.

[0088] Piezoelectric elements 10a and 10b

[0089] The material of the piezoelectric body 40 is PZT

[0090] Width in X and Y directions: 3.5mm

[0091] Height in Z direction: 3mm

[0092] Number of stacked piezoelectric layers 41 in the first region 46: 50

[0093] Number of first area 46: 3

[0094] Material of support member 12a: Stainless steel

[0095] Material of the first member 30: Acrylic resin

[0096] Material of the second member 20: Acrylic resin

[0097] Will Figure 2 The second component of (c) is set to component A. Figure 6 (a) and Figure 6 (b) is a cross-sectional view of the second component in Experiment 1. Figure 6 As shown in (a) of FIG. 1 , in component B, the surface on the +Z side of the head 32 is flat. Figure 6 As shown in (b) of FIG. 1 , in the component C, the peripheral edge portion of the surface on the +Z side of the head portion 32 is inclined in the -Z direction.

[0098] The materials of the first component 30, the second component 20, the supporting components 12a and 12b, and the structures of the piezoelectric elements 10a and 10b were the same as those in Experiment 1. The width of the head 32 of the first component 30 in the X and Y directions was 10 mm, the height of the head 32 in the Z direction was 2.5 mm, the amount of depression of the vertex of the inverted cone of the +Z surface of the head 32 was 1.5 mm, the width of the threaded portion 34 in the X and Y directions was 6 mm, and the height of the threaded portion 34 in the Z direction was 5 mm. The width of the second component 20 in the X and Y directions was 8 mm, the height was 15 mm, the depth of the recessed portion 28 in the Z direction was 14 mm, the depth of the first portion 22 in the Z direction was 6 mm, and the width of the second portion 24 in the X and Y directions was 4.5 mm.

[0099] Table 1 is a table showing the experimental conditions and results of samples A to C in Experiment 1.

[0100] [Table 1]

[0101]

[0102] In Table 1, samples A to C are samples using components A to C as the first component 30. "Vp-p" is equivalent to Figure 5The amplitude A1 is. "Carrier wave" is the frequency of carrier wave 64, which is the resonant frequency (second harmonic) of housing 25. "Signal wave" is the frequency of the signal wave. The modulation degree M is 100% in all samples. "D1" is Figure 4 The distance D1 in the +Z direction from the first component 30 with a sound pressure level of 85 dB in the above figure is the distance D1 in the +Z direction from the first component 30. The “tactile sensation” is the result of a survey on whether a tactile sensation can be obtained when the hand is suspended in the +Z direction of the first component 30. “1” indicates that a tactile sensation can be obtained, “2” indicates that a tactile sensation can be obtained slightly, and “3” indicates that a tactile sensation can not be obtained at all.

[0103] As shown in Table 1, Vp-p is roughly the same in samples A to C, and the frequency of the carrier wave is roughly the same. The frequency of the signal wave is the frequency that the Pacinian corpuscle can feel most sensitively. Sample A has the largest distance D1 compared to samples B and C, and is most capable of obtaining a sense of touch. In samples B and C, the distance D1 is roughly the same, but the sense of touch of sample C is greater. As described above, it can be seen that sample A is most capable of obtaining a sense of touch. In addition, it can be seen that the sense of touch in the air can be obtained in samples A to C.

[0104] Table 2 is a table showing experimental conditions and results using commercially available piezoelectric elements.

[0105] [Table 2]

[0106]

[0107] In Table 2, samples D and E use a commercially available lateral displacement mode piezoelectric element and a disc-shaped vibration plate, and a component capable of emitting sound waves, such as component A, is provided on the piezoelectric element. The planar shape of the piezoelectric element in samples D and E is circular, and the diameters are 10 mm and 15 mm, respectively. Thus, the piezoelectric elements of samples D and E are large. "D1" is the distance D1 when the sound pressure level is 80 dB.

[0108] As shown in Table 2, in samples D and E, since the sound pressure level for judgment is lower than that in Table 1, a strict comparison cannot be made, but the distance D1 of samples D and E is about the same as that of sample A. The plane area of ​​the piezoelectric element of samples D and E is more than 5 times that of sample A. As described above, sample A does not use a vibration plate, but uses piezoelectric elements 10a and 10b that are smaller than those of samples D and E, and can obtain the same degree of aerial tactile sensation as samples D and E. In this way, in sample A, miniaturization and high output can be achieved.

[0109] According to Example 2, Figure 4 As shown, the vibration generating device of Example 1 is used to form a structure in which the first component 30 outputs sound waves to the space in the Z direction. Figure 5As shown, a modulated wave 66 obtained by amplitude-modulating a carrier wave 64 having a frequency of the resonant frequency of the housing 25 using a signal wave having a frequency lower than that of the carrier wave 64 can be supplied to the piezoelectric elements 10a and 10b as a voltage. Thus, a high-output sound wave can be output to space using the vibration generating element 100 that can be miniaturized because a vibration plate is not used, thereby increasing the tactile sensation in the air.

[0110] When the frequency of the carrier wave 64 is in the range of 0.86 times or more and 1.14 times or less of the resonant frequency, a tactile sensation in the air can be obtained. More preferably, the frequency of the carrier wave 64 is in the range of 0.9 times or more and 1.1 times or less of the resonant frequency. In addition, the resonant frequency may be the resonant frequency of the fundamental mode or the resonant frequency of the higher harmonic mode. The frequency of the carrier wave 64 is, for example, in the range of 20 kHz or more and 110 kHz or less, preferably in the range of 30 kHz or more and 90 kHz or less.

[0111] The frequency of the signal wave is felt by Pacinian corpuscles and is therefore preferably 70 Hz to 1000 Hz, more preferably 110 Hz to 300 Hz. The modulation degree M is preferably 50% or more, more preferably 80% or more.

[0112] As in sample A, the center of the surface on the space side (+Z side) of the first component 30 is recessed toward the piezoelectric element 10b. As a result, as shown in Table 1, the tactile sensation in the air can be further increased. The cross-sectional shape of the recess of the first component 30 can be a triangle with the center as the vertex as in sample A, or a curve such as a parabola with the center as the vertex. The maximum recess amount of the +Z surface of the head 32 is preferably not less than 1 / 10 times and not more than 1 / 2 times the width of the head 32.

[0113] [Variation 1 of Example 2]

[0114] Figure 7 This is a diagram showing a modulated wave supplied by a driving device to a piezoelectric element in a first variation of the second embodiment. Figure 7The horizontal axis represents time, and the vertical axis represents voltage. In variant 1 of embodiment 2, a first modulated wave is generated by amplitude modulating a second carrier wave of period T2 (frequency f2) using a signal wave of period T3 (frequency f3). A second modulated wave 66 is formed by amplitude modulating a first carrier wave of period T1 (frequency f1) using the amplitude-modulated first modulated wave. The envelope 65a is a waveform in which the signal wave and the second carrier wave overlap. The frequency f1 of the first carrier wave 64 is the resonant frequency of the shell 25 (for example, greater than 0.86 times and less than 1.14 times the resonant frequency), for example, 20kHz to 110kHz. The frequency f2 of the second carrier wave is the frequency to which the Pacinian corpuscles are sensitive, for example, 50Hz to 300Hz. The frequency f3 of the signal wave is the frequency to which the Messner corpuscles, which are receptors of the human skin, are sensitive, for example, 1Hz to 60Hz. The other structures are the same as those in embodiment 2, and the description is omitted.

[0115] As described above, in the modification 1 of the embodiment 2, a signal having a frequency to which the Pacinian corpuscles are sensitive is used as the second carrier wave, and a signal having a frequency to which the Meissner corpuscles are sensitive is used as the signal wave. For example, by changing the frequency f1, different tactile sensations in the air can be obtained. For example, when the frequency f2 is set to 3 Hz, a tactile sensation like snapping can be obtained, and when the frequency f2 is set to 30 Hz, a tactile sensation like buzzing can be obtained.

[0116] [Variation 2 of Example 2]

[0117] Modification 2 of Embodiment 2 is an example in which a plurality of vibration generating elements 100 of Embodiment 1 are provided. Figure 8 Schematic diagram of a vibration generating device according to a second variation of the second embodiment. Figure 8 As shown, in the vibration generating device 102 of the variation 2 of the embodiment 2, a plurality of vibration generating elements 100 of the embodiment 1 are fixed on the base 60. The driving device 62 can output modulated waves to the plurality of vibration generating elements 100. The plurality of vibration generating elements 100 can emit sound waves 54 from the first component 30 to the Z direction. When a part of the human body is suspended in the +Z direction of the first component 30 of the plurality of vibration generating elements 100, a stronger sense of touch can be obtained through the plurality of sound waves 54. The driving device 62 can output modulated waves of the same waveform to the plurality of vibration generating elements 100, or can output modulated waves of different waveforms to the plurality of vibration generating elements 100. The number of vibration generating elements 100 can be appropriately set. The other structures are the same as those in the embodiment 2, and the description is omitted.

[0118] Example 3

[0119] Example 3 is an example in which the vibration generating element 100 of Example 1 is used in a vibration generating device such as a speaker. Fig. 9 Schematic diagram of the vibration generating device of Example 3. Fig. 9 middle, Figure 1 The +Z direction in (b) is the vertical direction.

[0120] like Fig. 9 As shown, in the vibration generating device 103 of the third embodiment, the vibration generating element 100 of the first embodiment is arranged on the pushed component 72 in a manner that the first component 30 is at the bottom and the second component 20 is at the top. The pushing component 70 is arranged on the second component 20. The pushing component 70 is a counterweight with a large load, and can push the second component 20 toward the pushed component 72 as shown by the arrow 56. The driving device 62 can supply a voltage having a waveform equivalent to the sound emitted by the pushed component 72 to the vibration generating element 100.

[0121] Fig.10 (a) is a plan view of the pushing member of Example 3 viewed from the +Z direction, Fig.10 (b) is Fig.10 (a) AA cross-section diagram. Fig.10 (a) and Fig.10 As shown in (b) , the biasing member 70 is annular in shape with an opening 75 in the center, and has three recesses 74 on the +Z side surface. The three recesses 74 are provided rotationally symmetrically with respect to the center of the planar shape of the biasing member 70 . Fig. 9 The second component 20 of the vibration generating element 100 can be inserted into the recess 74. It is sufficient as long as the second component 20 of the vibration generating element 100 is inserted into at least one of the recesses 74. In the recess 74 where the vibration generating element 100 is not inserted, a dummy component of the same height as the vibration generating element 100 can be inserted. The pushing component 70 is a metal or an insulator such as aluminum or stainless steel. The pushing component 70 is preferably hard and heavy. The shape of the pushing component 70 can be set arbitrarily.

[0122] The vibration generating element 100 may be the same as the vibration generating element 100 of the first embodiment, but the first component 30 preferably has a material and a shape that can easily transmit vibration to the pushed component 72. Therefore, the first component 30 is preferably made of a hard material (having a high Young's modulus). Figure 6 The +Z plane is flat like the component B in (a), and the widths of the head 32 in the X and Y directions are preferably larger than the widths of the second component 20 in the X and Y directions.

[0123] The urged member 72 is made of a hard material such as glass or metal, and is, for example, a top plate of a workbench.

[0124] According to the third embodiment, a voltage can be supplied to the piezoelectric element 10a of the vibration generating element 100, so that the pushing member 70 pushes the surface of the first member 30 in the +Z direction against the pushed member 72, and a sound wave is generated from the pushed member 72. Thus, the vibration is transmitted from the first member 30 to the pushed member 72, and a sound can be generated from the pushed member 72. The vibration generating element 100 of the first embodiment has a high Q value of mechanical vibration, and therefore, the sound generated from the pushed member 72 becomes a clear sound with good sound quality.

[0125] Although the weight is used as an example of the biasing member 70 in the above description, any member that can bias the first member 30 of the vibration generating element 100 against the biased member 72 may be used.

[0126] Example 4

[0127] Fig.11 is a cross-sectional view of the vibration generating element of Example 4. Fig.11 As shown, in the vibration generating element 104 of Example 4, the housing 25a has a first component 30a, a second component 30b, and a third component 20a joined to the first component 30a and the second component 30b. The through hole 28a penetrates the third component 20a in the Z direction. The central part of the through hole 28a in the Z direction is the third part 24a, the -Z side of the part 24a in the through hole 28a is the part 22a, and the +Z side of the part 24a is the part 22b. The side surfaces of the parts 22a and 22b are provided with thread teeth that become internal threads.

[0128] The first component 30a and the second component 30b have a head 32 and a threaded portion 34. A threaded tooth that becomes an external thread is provided on the side of the threaded portion 34. In the through hole 28a, the support component 12a, the piezoelectric elements 10a, 10b and the support component 12b are inserted in sequence from the -Z side. The threaded portion 34 of the first component 30a can be joined to the first part 22a by fitting the threaded tooth into the first part 22a of the through hole 28a of the third component 20a. The threaded portion 34 of the second component 30b can be joined to the second part 22b by fitting the threaded tooth into the second part 22b of the through hole 28a of the third component 20a. Thus, the first component 30a can press the piezoelectric element 10a in the +Z direction as shown by the arrow 50a via the support component 12a, and the second component 30b can press the piezoelectric element 10b in the -Z direction as shown by the arrow 50b via the support component 12b. As described above, by threading the first component 30a and the third component 20a together, and threading the second component 30b and the third component 20a together, the first component 30a and the second component 30b can press the piezoelectric elements 10a and 10b from both sides in the Z direction. Thus, the vibration of the piezoelectric elements 10a and 10b in the Z direction can be further enhanced and transmitted.

[0129] In order to improve the transmission characteristics of vibration, the material of the first component 30a and the second component 30b is preferably a material with a high Young's modulus, such as stainless steel. The Young's modulus of the first component 30a and the second component 30b is preferably higher than the Young's modulus of the piezoelectric body 40, preferably more than 1.2 times the Young's modulus of the piezoelectric body 40, and more preferably more than 1.5 times. It is preferred that the tightening direction of the thread of the first component 30a is symmetrical with the tightening direction of the thread of the second component 30b (for example, right-hand thread and left-hand thread). Thereby, the loosening of the first component 30a and the second component 30b can be suppressed. The other structures are the same as those in Example 1, and the description is omitted.

[0130] [Variation 1 of Example 4]

[0131] Modification 1 of Example 4 is an example in which the vibration generating element 104 of Example 4 is used in a vibration generating device such as a speaker. Fig.12 It is a schematic diagram of a vibration generating device of variant example 1 of embodiment 4.

[0132] like Fig.12 As shown, in the vibration generating device 105 of the modification 1 of the embodiment 4, the second component 30b of the vibration generating element 104 of the embodiment 4 is in contact with the pushed component 72, and the first component 30a is in contact with the pushing component 70. The pushing component 70 is a counterweight with a large load, and can push the second component 30b against the pushed component 72 as shown by the arrow 56. The driving device 62 can supply a voltage having a waveform equivalent to the sound emitted by the pushed component 72 to the vibration generating element 104.

[0133] [Experiment 2]

[0134] The amplitude of the vibration of a portion of the upper surface of the urged member 72 at a certain distance from the vibration generating element is measured.

[0135] Condition F: The vibration generating element 100 of Example 1, without the urging member 70

[0136] Condition G: The vibration generating element 104 of Example 4, without the urging member 70

[0137] Condition H: The vibration generating element 104 of Example 4 and the urging member 70 are provided

[0138] The first component 30a and the second component 30b are Figure 6The shape of the component B of (a) is made of stainless steel (SUS401: Young's modulus is about 200 GPa). The materials of the pushed component 72 and the pushing component 70 are stainless steel. The weight of the pushing component 70 is about 200 g. The materials and dimensions of the other components are the same as those of Example 1. The voltage supplied by the driving device 62 to the piezoelectric elements 10a and 10b is a sine wave with a frequency of 250 Hz.

[0139] Fig.13 Graph showing the amplitude relative to Vp-p in Experiment 2. Vp-p on the horizontal axis corresponds to the amplitude of a 250 Hz signal, and the amplitude represents the amplitude of the vibration of the upper surface of the pushed component 72. Fig.13 As shown, in each condition F to H, the amplitude increases when Vp-p is increased. In condition G, the amplitude increases under the same Vp-p compared to condition F. When Vp-p is approximately 22V, the amplitude of condition G is approximately 2.1μm. In condition H, the amplitude increases under the same Vp-p compared to condition G. When Vp-p is approximately 22V, the amplitude of condition H is approximately 2.5μm. As shown in Experiment 2, the vibration generating element 104 can have a higher output than the vibration generating element 100. In addition, by providing a pushing component 70, a higher output can be achieved.

[0140] [Variation 2 of Example 4]

[0141] The vibration generating element 104 of the fourth embodiment is used instead of the vibration generating element 104 of the third embodiment. Fig. 9 The vibration generating element 100 in the embodiment of the present invention is configured such that the pushed component 72 is a glass plate and is used as the pushing component 70. Fig.10 (a) and Fig.10 (b) The pushing member 70 has a weight of about 1 kg. A commercially available electromagnetic speaker is used to reproduce the low and middle ranges, and the vibration generating device of the second variation of the fourth embodiment is used to reproduce the high range. In the sound system, bird calls and saxophone music can be reproduced in the entire frequency band of the reproduction, and clear sound can be reproduced.

[0142] [Variation 3 of Example 4]

[0143] Fig.14 Schematic diagram of a vibration generating device according to a third variation of the fourth embodiment. Fig.14 As shown, in the vibration generating device 106 of the modification 3 of the embodiment 4, the plate 76 is provided with a through hole 76a, and the vibration generating element 104 of the embodiment 4 is embedded in the through hole 76a. The first component 30a extends from one surface of the plate 76, and the second component 30b extends from the other surface of the plate 76. The driving device 62 can supply the vibration generating element 104 with the following Figure 5As a result, sound waves can be emitted in two directions of the plate 76 as shown by arrows 54a and 54b. By using the vibration generating element 104, the tactile sensation in the air can be increased. In addition, sound waves can be emitted in two directions.

[0144] In Examples 1 to 4 and their variations, the material of the first component 30, 30a and the second component 30b is preferably a light material (such as resin) such as acrylic resin in a vibration generating device that generates ultrasonic waves, and is preferably a heavy material (such as metal) such as stainless steel in a vibration generating device that generates sound in the audible range.

[0145] Example 5

[0146] A tactile sense generating device capable of obtaining a soft tactile sense will be described. Fig.15 1 is a schematic diagram of a tactile sense generating device according to Example 5. The normal direction of the upper surface of the base 160 is defined as the Z direction, and directions orthogonal to the Z direction are defined as the X direction and the Y direction.

[0147] like Fig.15 As shown, in the tactile sense generating device 200 of the fifth embodiment, a vibrator 115 is provided on the base 160. The vibrator 115 mainly vibrates in the Z direction. The vibrator 115 includes a housing 125 formed by joining a first component 130 and a second component 120. The driving device 162 can apply a voltage to the vibrator 115 so that the vibrator 115 vibrates.

[0148] Fig.16 (a) is a plan view of the vibrator in Example 5, Fig.16 (b) is Fig.16 AA cross-section view of (a). Fig.17 (a) is a plan view of the second part of the vibrator in Example 6, Fig.17 (b) is Fig.17 (a) AA cross-section view, Fig.17 (c) is a cross-sectional view of the first component. The direction in which the first component 130 and the second component 120 sandwich the piezoelectric elements 110a and 110b is defined as the Z direction, and the directions in which the sides of the piezoelectric elements 110a and 110b extending in a plan view and perpendicular to the Z direction are defined as the X direction and the Y direction.

[0149] like Fig.16 (a) to Fig.17As shown in (c), in the vibrator 115 of the tactile generating device 200 of Example 5, the housing 125 includes a first component 130 and a second component 120. The first component 130 is joined to the second component 120. A recess 128 is provided on the surface of the second component 120 in the +Z direction. The recess 128 has a first portion 122 provided on the +Z side and a second portion 124 provided on the -Z side. The planar shape of the first portion 122 is a substantially circular shape, and the planar shape of the second portion 124 is a substantially rectangular shape. A thread 126 forming an internal thread is formed on the side surface of the first portion 122. No thread is formed on the side surface of the second portion 124. In the recess 128, the support component 112a, the piezoelectric elements 110a, 110b, and the support component 112b are inserted in sequence from the -Z side. The support component 112a, the piezoelectric elements 110a, 110b, and the support component 112b are not joined to the second component 120 and are movable.

[0150] The first component 130 includes a head 132 provided on the +Z side and a threaded portion 134 provided on the -Z side. The planar shape of the head 132 is substantially circular. The central portion of the surface on the +Z side of the head 132 when viewed from above is recessed in an inverted cone shape relative to the peripheral portion in the -Z direction. A thread 136 forming an external thread is formed on the side surface of the threaded portion 134. The threaded portion 134 of the first component 130 can be engaged with the first portion 122 of the recess 128 of the second component 120 by fitting the thread 126 with the thread 136. By tightening the thread, the second component 120 can press the piezoelectric element 110a in the +Z direction as indicated by the arrow 150a via the support component 112a. The first component 130 can press the piezoelectric element 110b in the -Z direction as indicated by the arrow 150b via the support component 112b. The stress pressing the piezoelectric elements 110a and 110b is, for example, 5×10 6 Pa or above.

[0151] The material of the first member 130 and the second member 120 is, for example, metal or resin. The material of the supporting members 112a and 112b is a material having a Young's modulus greater than that of the first member 130, the second member 120, and the piezoelectric elements 110a and 110b, and is, for example, stainless steel. The width of the head 132 of the first member 130 in the X direction and the Y direction is 10 mm as an example, the height of the head 132 in the Z direction is 2.5 mm as an example, the amount of depression of the top of the inverted cone shape of the +Z surface of the head 132 is 1.5 mm as an example, the width of the threaded portion 134 in the X direction and the Y direction is 6 mm as an example, and the height of the threaded portion 134 in the Z direction is 5 mm as an example. The width of the second member 120 in the X and Y directions is 8 mm as an example, the height is 15 mm as an example, the depth of the recess 128 in the Z direction is 14 mm as an example, the depth of the first portion 122 in the Z direction is 6 mm as an example, and the width of the second portion 124 in the X and Y directions is 4.5 mm as an example. The materials, shapes, and sizes of the first member 130, the second member 120, and the supporting members 112a and 112b can be appropriately designed.

[0152] Fig.18 is a cross-sectional view of the piezoelectric element in Example 5. Fig.18 As shown, the piezoelectric elements 110a and 110b include a piezoelectric body 140 composed of a plurality of piezoelectric layers 141, a plurality of first electrodes 142, and a plurality of second electrodes 144. The plurality of piezoelectric layers 141 are stacked in the Z direction. The piezoelectric layer 141, the first electrode 142, and the second electrode 144 are in the shape of a flat plate extending on the XY plane. The plurality of first electrodes 142 and the plurality of second electrodes 144 are arranged alternately in the Z direction. One piezoelectric layer 141 is sandwiched by one first electrode 142 and one second electrode 144 in the Z direction. A first external electrode 143 is arranged on the side surface of the -X side of the piezoelectric body 140, and a second external electrode 145 is arranged on the side surface of the +X side of the piezoelectric body 140. The plurality of first electrodes 142 are electrically connected to the first external electrode 143. The plurality of second electrodes 144 are electrically connected to the second external electrode 145. By applying a voltage between the first external electrode 143 and the second external electrode 145, the piezoelectric body 140 can expand and contract in the Z direction as indicated by arrow 152 by utilizing the inverse piezoelectric effect. The vibration mode in which the piezoelectric body 140 expands and contracts in the stacking direction of the first electrode 142 and the second electrode 144 by applying a voltage to the first electrode 142 and the second electrode 144 is called a longitudinal displacement mode or a d33 mode.

[0153] The piezoelectric body 140 includes a first region 146, a second region 147, and a third region 148. The first region 146 and the second region 147 are alternately arranged in the Z direction. The third region 148 is arranged outside the outermost first region 146 in the Z direction. The first region 146 is a region where the first electrode 142 and the second electrode 144 are alternately arranged at a certain interval in the Z direction. As an example, the number of stacking layers of the piezoelectric layer 141 in the first region 146 is 50 layers. The second region 147 and the third region 148 are regions where the first electrode 142 and the second electrode 144 are not arranged. The second region 147 may not be arranged. There is also a case where reliability is improved by setting the second region 147.

[0154] As the material of the piezoelectric layer 141, for example, lead zirconate titanate (PZT: Pb(Zr, Ti)O3), barium titanate materials (BaTiO3, Ba may also be Ca, Ti may also be Zr), bismuth titanate materials (BiTiO3, part of Bi may also be Na), alkali niobate materials (NaNbO3, Na may also be Li or K) may be used. As the material of the first electrode 142, the second electrode 144, the first external electrode 143 and the second external electrode 145, for example, metals such as Ag, Pd, Pt, Cu, Ni and Au may be used. The piezoelectric elements 110a and 110b are sheets composed of a sintered body formed by stacking and sintering piezoelectric sheets having the first electrode 142 and the second electrode 144 formed on the surface. The piezoelectric elements 110a and 110b are, for example, rectangular parallelepipeds, and the widths of the piezoelectric elements 110a and 110b in the X direction and the Y direction are, as an example, 3.5 mm, and the heights in the Z direction are, as an example, 3 mm.

[0155] When the displacement of the surface on the ±Z side of the piezoelectric elements 110a and 110b in the Z direction is ΔZ, the number of stacked piezoelectric layers 141 is N, the voltage applied between the first electrode 142 and the second electrode 144 is V, and the constant related to the inverse piezoelectric constant is d33, ΔZ = d33 × V × N. Therefore, by increasing the number of stacked layers N of the piezoelectric layer 141, the displacement ΔZ becomes larger. However, due to manufacturing constraints, etc., there is a situation where the number of stacked layers N in one piezoelectric element 110a or 110b cannot be increased. In such a case, the piezoelectric elements 110a and 110b can be stacked in the Z direction within the housing 125. Thereby, the total displacement of the piezoelectric elements 110a and 110b can be increased. The number of piezoelectric elements 110a and 110b stacked in the Z direction can be one or more than three.

[0156] Fig.19 This is a diagram showing the modulated wave supplied by the driving device to the piezoelectric element in Example 5. Fig.19The horizontal axis in the figure represents time, and the vertical axis represents voltage. The signal of the carrier wave period T1 (frequency f1) is the carrier wave 164. The envelope 165 of the modulated wave 166 corresponds to the signal wave. The signal wave has a period T2 (frequency f2). A sine wave is used as the carrier wave 164, but for the sake of simplicity, a triangular wave is shown as the carrier wave 164. In addition, the period T1 is much smaller than the period T2, but for the sake of easy understanding, it is shown in FIG. Fig.19 The period T1 is magnified for illustration. In the modulated wave 166, the carrier wave 164 is amplitude modulated by the signal wave. The carrier wave 164 is a sine wave, and the signal wave is a rectangular wave.

[0157] The frequency f1 of the carrier wave 164 is, for example, the resonant frequency of the housing 125. The resonant frequency may be a fundamental wave or a higher harmonic. The frequency f2 of the signal wave is a frequency that the Messner corpuscles, which are receptors of the human skin, can sensitively sense. Such a frequency is, for example, greater than 1 Hz and less than 60 Hz.

[0158] When the maximum amplitude of envelope 165 in modulated wave 166 is A1 and the minimum amplitude of envelope 165 is A2, modulation degree M is defined as M=(A1-A2) / (A1+A2). Modulation degree M of modulated wave 166 is, for example, 50% or more and less than 100%.

[0159] The rectangular wave is a waveform whose rising edge time and falling edge time are sufficiently smaller than the period T2. The rising edge time and falling edge time of the rectangular wave are, for example, less than 1 / 25 times of the period T2, preferably less than 1 / 100 times. In addition, the definition of the rising edge time and the falling edge time is subject to the Japanese Industrial Standard JIS C 161-02-05. That is, the rising edge time and the falling edge time are the difference between the time when the voltage of the envelope 165 is 10% of the voltage when the amplitude A1 is compared with the voltage when the amplitude A2 is 90% of the voltage.

[0160] [Experiment 3]

[0161] The tactile softness of the +Z side of the first member 130 was examined.

[0162] The materials of the components used in the experiments are as follows.

[0163] Piezoelectric elements 110a and 110b

[0164] The material of the piezoelectric body 140 is PZT

[0165] The materials of the first electrode 142 and the second electrode 144 are silver-palladium.

[0166] Width in X and Y directions: 3.5mm

[0167] Height in Z direction: 3mm

[0168] Number of stacked piezoelectric layers 141 in the first region 146: 50

[0169] Number of first area 146: 3

[0170] Material of support member 112a: Stainless steel

[0171] Material of the first member 130: Acrylic resin

[0172] Material of the second member 120: Acrylic resin

[0173] The width of the head 132 of the first component 130 in the X and Y directions is 10 mm, the height of the head 132 in the Z direction is 2.5 mm, the depression amount of the inverted cone-shaped vertex of the +Z surface of the head 132 is 1.5 mm, the width of the threaded portion 134 in the X and Y directions is 6 mm, and the height of the threaded portion 134 in the Z direction is 5 mm. The width of the second component 120 in the X and Y directions is 8 mm, the height is 15 mm, the depth of the recess 128 in the Z direction is 14 mm, the depth of the first portion 122 in the Z direction is 6 mm, and the width of the second portion 124 in the X and Y directions is 4.5 mm.

[0174] Table 3 is a table showing the experimental conditions and results in Experiment 3.

[0175] [Table 3]

[0176]

[0177] In Table 3, conditions A to I are conditions of the modulation wave supplied by the driving device 162 as the voltage between the first electrode 142 and the second electrode 144 of the piezoelectric elements 110a and 110b. "Waveform" is the waveform of the signal wave, and "rectangular wave" means that the waveform of the signal wave is as follows: Fig.19 The "sine wave" indicates that the waveform of the signal wave is a sine wave, and the "sawtooth wave" indicates that the waveform of the signal wave is a sawtooth wave (also called a falling ramp wave) with a sharp falling edge and a gradually rising edge. The "carrier wave" is the frequency of the carrier wave 164, which is 66kHz in any condition. The resonant frequency (second harmonic) of the housing 125 is 63.5kHz. The "signal wave" is the frequency of the signal wave. The "modulation degree" is Fig.19 The modulation degree M described in the above is 88% for all samples. "Tactile sensation" is the result of investigating the softness of the tactile sensation when touching the first component 130. "1", "2", "3" and "4" indicate the degree of soft tactile sensation, and the degree of soft tactile sensation decreases from "1" to "4". When "1" is reached, the softest tactile sensation can be obtained, and when "4" is reached, the soft tactile sensation cannot be obtained. When "1" is reached, the tactile sensation is like touching a balloon.

[0178] As shown in Table 3, in conditions A to G, a rectangular wave is used as a signal wave, and the frequency of the signal wave is changed. When the frequency of the signal wave is 31 Hz and 3 Hz, a soft touch cannot be obtained. When the frequency of the signal wave is 25 Hz and 8 Hz, a slightly soft touch can be obtained, when the frequency of the signal wave is 19 Hz and 13 Hz, a softer touch can be obtained, and when the frequency of the signal wave is 16 Hz, the softest touch can be obtained.

[0179] Condition H indicates the frequency (28 Hz) at which the softest tactile sensation is obtained by changing the frequency of the sine wave signal wave. Condition I indicates the frequency (21 Hz) at which the softest tactile sensation is obtained by changing the frequency of the sawtooth wave signal wave. When the waveform of the signal wave is a sine wave or a sawtooth wave, even at the frequency of the signal wave that obtains the softest tactile sensation, the "tactile sensation" is 2, and the softest tactile sensation is smaller than that of condition D.

[0180] The conditions other than the frequency of the carrier wave 164 were made the same as the condition D, and the frequency of the carrier wave 164 was changed to investigate the tactile sensation of the first component 130. Within the range of ±14% (54.7kHz to 72.3kHz) of the resonant frequency 63.5kHz, the soft tactile sensation was almost unchanged. When the frequency of the carrier wave 164 deviated from the range of ±14% of the resonant frequency, the soft tactile sensation was attenuated. The soft tactile sensation was attenuated as the frequency of the carrier wave 164 was away from the resonant frequency.

[0181] The conditions other than the modulation degree are made the same as condition D, and the modulation degree M of the modulation wave 166 is changed to investigate the tactile sensation of the first component 130. When the modulation degree M is 100%, no soft tactile sensation is obtained. When the modulation degree M is reduced, the soft tactile sensation increases. When the modulation degree M is 88%, the soft tactile sensation is the largest, and it is a tactile sensation like touching a balloon. When the modulation degree M is 70%, it is a soft tactile sensation that is roughly the same as when the modulation degree M is 88%, but the tension of the balloon is slightly reduced. When the modulation degree M is 50%, the soft tactile sensation decreases, and it is a feeling that the air in the balloon is leaking. When the modulation degree M is 20%, no soft tactile sensation is obtained.

[0182] According to the above results, in Example 5, the driving device 162 generates a modulation wave 166 having a modulation degree M less than 100% by amplitude modulating the carrier wave 164 having the resonant frequency of the vibrator 115 with a signal wave having a rectangular wave and a frequency lower than the frequency of the carrier wave 164 and which can be felt by the Messner corpuscles, and supplies the modulation wave 166 to the vibrator 115. As a result, when the hard first component 130 is touched, a soft tactile sensation is obtained.

[0183] In order to obtain a soft touch, the frequency of the carrier wave 164 is preferably 0.86 times or more and 1.14 times or less of the resonant frequency of the vibrator 115 (i.e., the shell 125), more preferably 0.9 times or more and 1.1 times or less of the resonant frequency, and further preferably 0.95 times or more and 1.05 times or less of the resonant frequency. The frequency of the signal wave is a frequency that the Messner corpuscle can sensitively feel, preferably 1 Hz or more and 60 Hz or less, more preferably 3 Hz or more and 50 Hz or less, and further preferably 13 Hz or more and 28 Hz or less. The modulation degree M of the modulation wave 166 is preferably 50% or more and 98% or less, and more preferably 70% or more and 90% or less. The duty cycle of the modulation wave 166 (period / period T2 when the amplitude is A1) is preferably around 50%. The duty cycle can be 20% or more and 80% or less, 30% or more and 70% or less, or 40% or more and 60% or less.

[0184] The vibrator 115 used in Example 5 uses piezoelectric elements 110a and 110b whose vibration mode is mainly a longitudinal displacement mode, and the housing 125 presses the piezoelectric elements 110a and 110b. By pressing the piezoelectric elements 110a and 110b by the housing 125, the Q value is improved compared to the case where the housing 125 does not press the piezoelectric elements 110a and 110b. Such a phenomenon cannot be obtained when using piezoelectric elements of a lateral displacement mode as the piezoelectric elements 110a and 110b, and is the first phenomenon discovered by the inventor of the present invention. In addition, the lateral displacement mode refers to a mode in which the vibration direction of the piezoelectric elements 110a and 110b is orthogonal to the stacking direction of the first electrode 142 and the second electrode 144. The resonant frequency does not change much with respect to the presence or absence of the pressing of the piezoelectric elements 110a and 110b. It can be considered that this is because the supporting member 112a is provided.

[0185] According to the results of Experiment 3, using Fig.18 In this way, the piezoelectric layer 141 is sandwiched between the first electrode 142 and the second electrode 144 in the Z direction, and the piezoelectric elements 110a and 110b can be expanded and contracted in the Z direction by applying a voltage between the first electrode 142 and the second electrode 144. Fig.16 As in (b), the first component 130 and the second component 120 can press the piezoelectric element 110a in the Z direction, and the first component 130 can output vibration corresponding to the expansion and contraction of the piezoelectric elements 110a and 110b in the Z direction. As described above, by pressing the longitudinal displacement type piezoelectric elements 110a and 110b by the housing 125, the Q value of the mechanical vibration of the housing 125 is improved. Therefore, the characteristics of the tactile generating device can be improved.

[0186] The first component 130 and the second component 120 can press the piezoelectric elements 110a and 110b by engaging the threads. Thus, the piezoelectric elements 110a and 110b can be pressed stably with a large force. In addition, the deviation of the pressure applied to the piezoelectric elements 110a and 110b can be suppressed. Therefore, the deviation of the resonant frequency can be suppressed. As an example, when a plurality of structures are made, the deviation of the resonant frequency is less than 600 Hz. The mechanism for pressing the piezoelectric elements 110a and 110b can also be a mechanism other than thread engagement.

[0187] In Example 5, when the nominal diameter d (maximum diameter) of the thread 136 of the first component 130 is 6 mm, when the tightening torque T of the first component 130 is measured using a torque wrench, it is approximately 0.1 N·m. The force F of the first component 130 pressing the piezoelectric element 110b is T / (k×d), and when the torque coefficient k is 0.2, F=83N. The area of ​​the XY plane of the piezoelectric elements 110a and 110b is 3.5 mm×3.5 mm. Therefore, the pressure of the first component 130 pressing the piezoelectric element 110b is 6.8×10 6 Pa. It is believed that the effect of improving the Q value of the mechanical vibration of the housing 125 is effective even at a pressure of 6.8×10 6 Therefore, the pressure of the first component 130 and the second component 120 pressing the piezoelectric elements 110a and 110b is preferably 5×10 5 Pa or more, more preferably 1×10 6 Pa or more, more preferably 2×10 6 Pa or above.

[0188] A support member 112b (third member) is provided between the first member 130 and the piezoelectric element 110b, and a support member 112a (fourth member) is provided between the second member 120 and the piezoelectric element 110a. It is sufficient to provide at least one of the support members 112a and 112b. When PZT is used as the piezoelectric body 140, the Young's modulus of PZT is approximately 60 GPa. When a resin is used as the housing 125, the Young's modulus of the resin is 10 GPa or less. When stainless steel is used as the support members 112a and 112b, the Young's modulus of stainless steel is approximately 120 GPa. In addition, the Young's modulus of aluminum is approximately 70 GPa. As described above, the Young's modulus of the support member 112b is greater than the Young's modulus of the piezoelectric body 140 and the Young's modulus of the first member 130, and the Young's modulus of the support member 112b is greater than the Young's modulus of the piezoelectric body 140 and the Young's modulus of the second member 120. By providing the support members 112a and 112b, a load can be applied to the piezoelectric elements 110a and 110b, thereby strengthening the transmission of vibration. Therefore, the resonance frequency of the housing 125 can be suppressed from changing due to pressure, and the Q value can be further improved. It is sufficient to provide at least one of the support members 112a and 112b. The Young's modulus of the support members 112b and 112a is preferably 1.2 times or more of the Young's modulus of the piezoelectric body 140 and the Young's modulus of each of the first member 130 and the second member 120, and more preferably 1.5 times or more.

[0189] like Fig.18 As shown, in the piezoelectric elements 110a and 110b, the plurality of first electrodes 142 and the plurality of second electrodes 144 are alternately arranged in the Z direction, and one of the plurality of piezoelectric layers 141 is sandwiched in the Z direction by one of the plurality of first electrodes 142 and one of the plurality of second electrodes 144. With such a structure, the displacement in the Z direction can be further increased, and the characteristics of the tactile generating device can be further improved.

[0190] Fig. 20 (a) and Fig. 20 (b) is a cross-sectional view showing another example of the second component in Example 5. Fig. 20 As shown in (a), the surface on the +Z side of the head 132 of the first component 130 is flat. Fig. 20 As shown in (b), the peripheral edge of the surface on the +Z side of the head 132 of the first component 130 is inclined in the -Z direction. By changing the shape of the surface on the +Z side of the first component 130, different tactile sensations can be obtained. For example, when using Fig. 20 (a) and Fig. 20When the surface on the +Z side is flat or the first member 130 bulges in the +Z direction as in (b), a soft balloon-like feel like a bubble wrap can be obtained.

[0191] [Variation 1 of Example 5]

[0192] Fig.21 1 is a schematic diagram of a tactile sensation generating device according to a first variation of the fifth embodiment. A component 170 is shown in cross section on the side of the vibrator 115. Fig.21 As shown, in the tactile sense generating device 202 of the modification 1 of the embodiment 5, the second component 120 of the vibrator 115 is embedded in the component 170, and the component 170 surrounds the periphery of the first component 130. The component 170 does not contact the first component 130. The component 170 is a resin that is softer than the first component 130. As the component 170 contacts the second component 120, the vibration of the second component 120 can be transmitted to the component 170. Thus, a soft tactile sense can be generated in the component 170.

[0193] Example 6

[0194] Fig. 22 (a) is a cross-sectional view of the first part of the vibrator in Example 6, Fig. 22 (b) is a cross-sectional view of the second part of the vibrator in Example 6. Fig. 22 As shown in (a) of FIG. 1 , the first member 130 of the vibrator 115 in the sixth embodiment has a groove 133 provided on the surface on the +Z side. The other structures are the same as those of the first member in the fifth embodiment.

[0195] like Fig. 22 As shown in (b), the second component 120 of the vibrator 115 in Example 6 is larger than the second component of Example 5. A hole 127b that penetrates the second component 120 in the Y direction is provided in the -Z direction of the recess 128. The cross-sectional shape of the hole 127b is circular. A threaded hole 127a for threaded fixing on the base is provided on the surface of the -Z side of the second component 120. The other structures are the same as the first component of Example 5.

[0196] As in Embodiment 6, the shape and material of the housing 125 of the vibrator 115 can be appropriately selected.

[0197] Example 7

[0198] Fig.23 204 is a schematic diagram of a tactile sensation generating device in Example 7. A portion of the tactile sensation generating device 204 is shown in cross section. Fig.23As shown, a joint component 172 is fixed to the base 160. The joint component 172 is a cylindrical shape that is long in the vertical direction. A threaded hole 172a is provided on the upper surface of the joint component 172. The component 174 is a cylindrical shape that is long in the vertical direction. A threaded portion 174a is provided on the upper and lower surfaces of the component 174. The component 174 is fixed to the joint component 172 by threading the threaded portion 174a into the threaded hole 172a. A hole 174b extending in the horizontal direction is formed in the component 174. The vibrator 115 of Example 5 is embedded and fixed in the hole 174b. The driving device 162 is capable of applying force between the first electrode 142 and the second electrode 144 of the piezoelectric elements 110a and 110b of the vibrator 115 as shown in FIG. Fig.19 In this way, the modulated wave 166 is supplied. In the seventh embodiment, by holding the member 174 in the horizontal direction, a soft touch can be obtained on the member 174. The other structures are the same as those in the fifth embodiment, and the description thereof is omitted.

[0199] In the first modification of the fifth embodiment and the seventh embodiment, the component 170 or 174 contacts at least a portion of the housing 125 (for example, the second component 120 in the first modification of the fifth embodiment) and is softer than the portion of the housing 125 in contact. That is, the Young's modulus of the component 170 or 174 is smaller than the Young's modulus of the housing 125. Thus, vibration is transmitted from the portion in contact with the housing 125 to the component 170 or 174. When the component 170 or 174 is touched, a soft tactile sensation can be obtained.

[0200] Example 8

[0201] Fig.24 (a) is a plan view of the tactile sensation generating device in Example 7, Fig.24 (b) is Fig.24 The AA cross-sectional view of (a) is shown in FIG. The directions in which the long side and the short side of the vibrator 115a extend in the plan view are the X direction and the Y direction, respectively, and the direction of the normal to the upper surface of the vibrator 115a is the Z direction.

[0202] like Fig.24 (a) and Fig.24 As shown in (b), in the tactile sensation generating device 206, the plane shape of the vibrator 115a is a long strip (a rectangle with a long side that is very long compared to the short side). The component 176 covers and contacts the vibrator 115a. The plane shape of the component 176 is also a long strip. The component 176 is softer than the vibrator 115a. The driving device 162 can supply the vibrator 115a with a Fig.19 Thus, vibration corresponding to the modulated wave 166 is generated in the vibrator 115a. The vibration of the vibrator 115a is in the X direction as indicated by the arrow 156.

[0203] Fig.25is a cross-sectional view of the vibrator in Example 8. Fig.25 As shown, the vibrator 115a is a piezoelectric element 110. The piezoelectric element 110 includes a piezoelectric body 140 composed of a plurality of piezoelectric layers 141, a plurality of first electrodes 142, and a plurality of second electrodes 144. The plurality of first electrodes 142 and the plurality of second electrodes 144 are arranged alternately in the Z direction. One piezoelectric layer 141 is sandwiched by one first electrode 142 and one second electrode 144 in the Z direction. A first external electrode 143 electrically connected to the first electrode 142 is provided on the side surface of the -X side of the piezoelectric body 140. A second external electrode 145 electrically connected to the second electrode 144 is provided on the side surface of the +X side of the piezoelectric body 140. In the case where the planar shape is a long strip in the X direction like the piezoelectric element 110, by applying a voltage between the first external electrode 143 and the second external electrode 145, the piezoelectric body 140 can expand and contract in the X direction as shown by the arrow 156. Such a vibration mode in which the first electrode 142 and the second electrode 144 expand and contract in the planar direction by applying a voltage is referred to as a lateral displacement mode or a d31 mode.

[0204] As in Example 8, the vibrator 115a may be a piezoelectric element 110 that mainly vibrates in a lateral displacement mode. Alternatively, the vibrator 115a may not be provided with a housing 125, and the piezoelectric element 110 may be in direct contact with the component 176. Alternatively, a piezoelectric element that mainly vibrates in a longitudinal displacement mode may be in direct contact with the component 176. Alternatively, the vibrator may vibrate by a mechanism other than a piezoelectric element. In these tactile sensation generating devices, a soft tactile sensation may also be generated.

[0205] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims.

Claims

1. A vibration generating device, characterized in that: include: A piezoelectric element comprising a piezoelectric layer and a first electrode and a second electrode sandwiching the piezoelectric layer, wherein the piezoelectric element can expand and contract in a direction in which the first electrode and the second electrode sandwich the piezoelectric layer by applying a voltage between the first electrode and the second electrode; and The housing includes a first component and a second component sandwiching the piezoelectric element in the direction, the first component and the second component can press the piezoelectric element in the direction, and the first component can output a sound wave corresponding to the expansion and contraction of the piezoelectric element in the direction.

2. The vibration generating device according to claim 1, characterized in that: The first member and the second member can press the piezoelectric element by fitting a thread provided on the first member with a thread provided on the second member.

3. The vibration generating device according to claim 1, characterized in that: comprising a third component engaged with the first component and the second component, The first member and the second member can press the piezoelectric element by fitting the thread provided on the first member with the thread provided on the third member and fitting the thread provided on the second member with the thread provided on the third member.

4. The vibration generating device according to any one of claims 1 to 3, characterized in that: Includes at least one of a fourth component and a fifth component, wherein the fourth component is arranged between the first component and the piezoelectric element and has a Young's modulus larger than the Young's modulus of the first component and the Young's modulus of the piezoelectric layer, and the fifth component is arranged between the second component and the piezoelectric element and has a Young's modulus larger than the Young's modulus of the second component and the Young's modulus of the piezoelectric layer.

5. The vibration generating device according to any one of claims 1 to 3, characterized in that: The pressure of the first component and the second component pressing the piezoelectric element is 5×10 5 Pa or above.

6. The vibration generating device according to any one of claims 1 to 3, characterized in that: The piezoelectric layer, the first electrode and the second electrode are respectively provided in plurality, the plurality of first electrodes and the plurality of second electrodes are alternately arranged in the direction, and one piezoelectric layer among the plurality of piezoelectric layers is sandwiched by one of the plurality of first electrodes and one of the plurality of second electrodes in the direction.

7. The vibration generating device according to any one of claims 1 to 3, characterized in that: The first component is capable of outputting the sound wave to the space in the direction, and A modulated wave obtained by amplitude-modulating a carrier wave having a frequency not less than 0.86 times and not more than 1.14 times the resonant frequency of the housing using a signal wave having a frequency lower than that of the carrier wave can be supplied to the piezoelectric element as the voltage.

8. The vibration generating device according to claim 7, characterized in that: The frequency of the signal wave is greater than or equal to 70 Hz and less than or equal to 1000 Hz.

9. The vibration generating device according to any one of claims 1 to 3, characterized in that: The first component is capable of outputting the sound wave to the space in the direction, and The piezoelectric element can be supplied with a second modulated wave as the voltage, which is obtained by amplitude modulating a first carrier wave having a frequency greater than 0.86 times and less than 1.14 times the resonant frequency of the shell using a first modulation wave, wherein the first modulation wave is obtained by amplitude modulating a second carrier wave having a frequency greater than 50 Hz and less than 300 Hz using a signal wave having a frequency greater than 1 Hz and less than 60 Hz.

10. The vibration generating device according to claim 7, characterized in that: A central portion of a surface of the first member on the space side is recessed toward the piezoelectric element.

11. The vibration generating device according to claim 7, characterized in that: A driving device is included that can supply the modulated wave as the voltage to the piezoelectric element.

12. The vibration generating device according to any one of claims 1 to 3, characterized in that: The voltage can be supplied to the piezoelectric element so that the surface of the first member in the direction is pushed against a pushed member, thereby generating an acoustic wave from the pushed member.

13. The vibration generating device according to claim 12, characterized in that: include: a pushing member capable of pushing the surface of the first member against the pushed member; and A driving device is capable of supplying the voltage to the piezoelectric element.

14. A tactile sensation generating device, characterized in that: include: Vibrator; and A driving device capable of amplitude-modulating a carrier wave having a frequency greater than 0.86 times and less than 1.14 times the resonant frequency of the vibrator using a signal wave having a frequency greater than 1 Hz and less than 60 Hz lower than the frequency of the carrier wave and being a rectangular wave, generating a modulated wave having a modulation degree greater than 50% and less than 100%, and supplying the modulated wave to the vibrator.

15. The tactile sensation generating device according to claim 14, characterized in that: The vibrator comprises: A piezoelectric element comprising a piezoelectric layer and a first electrode and a second electrode sandwiching the piezoelectric layer, wherein the piezoelectric element can expand and contract in a direction in which the piezoelectric layer is sandwiched between the first electrode and the second electrode by applying a voltage between the first electrode and the second electrode; and The housing includes a first member and a second member sandwiching the piezoelectric element in the direction, wherein the first member and the second member can press the piezoelectric element in the direction and output vibration corresponding to the expansion and contraction of the piezoelectric element.

16. The tactile sensation generating device according to claim 15, characterized in that: The first member and the second member can press the piezoelectric element by threading each other.

17. The tactile sensation generating device according to claim 15 or 16, characterized in that: Includes at least one of a third component and a fourth component, wherein the third component is arranged between the first component and the piezoelectric element and has a Young's modulus larger than the Young's modulus of the first component and the Young's modulus of the piezoelectric layer, and the fourth component is arranged between the second component and the piezoelectric element and has a Young's modulus larger than the Young's modulus of the second component and the Young's modulus of the piezoelectric layer.

18. The tactile sensation generating device according to claim 16 or 17, characterized in that: The pressure of the first component and the second component pressing the piezoelectric element is 5×10 5 Pa or above.

19. The tactile sensation generating device according to claim 16 or 17, characterized in that: The piezoelectric layer, the first electrode and the second electrode are respectively provided in plurality, the plurality of first electrodes and the plurality of second electrodes are alternately arranged in the direction, and one piezoelectric layer among the plurality of piezoelectric layers is sandwiched by one of the plurality of first electrodes and one of the plurality of second electrodes in the direction.

20. The tactile sensation generating device according to claim 16, characterized in that: A member is included that is in contact with at least a portion of the housing, is capable of transmitting vibration from the at least a portion, and is softer than the at least a portion.

21. The tactile sensation generating device according to claim 14 or 15, characterized in that: The degree of modulation is 98% or less.

22. The tactile sensation generating device according to claim 14 or 15, characterized in that: The frequency of the signal wave is greater than or equal to 3 Hz and less than or equal to 50 Hz.

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