Vibration generating device and electronic device

Abstract

To provide a vibration generating device and electronic device capable of presenting a new tactile sensation with a single piezoelectric actuator.SOLUTION: A vibration generating device 100 includes a tactile sensation extending member 103, which is a plate-shaped member having a tactile sensation extending function and a piezoelectric actuator 104. The tactile sensation extending member 103 includes a base having a first main surface and a second main surface opposite to the first main surface and a plurality of protrusions 112, which is a plurality of protrusions protruding from the first main surface, with the vertices of the plurality of protrusions located on a predetermined plane. The piezoelectric actuator 104 is bonded to the second main surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vibration generating device and an electronic device that provide a tactile sensation by vibration. [Background technology]

[0002] Various actuators are used in haptic function devices that present tactile sensations to users. For example, electromagnetic actuators such as eccentric motors and linear resonant actuators are used for notification functions. In addition to these electromagnetic actuators, piezoelectric actuators are also used for force feedback functions.

[0003] In recent years, tactile technology has become more sophisticated, and in force feedback functions in the low-frequency range (100 to 250 Hz), the range of tactile expression has been expanded by compound addition and modulation of drive signals. Also, in the high-frequency range (approximately 20 to 40 kHz), technology has been developed that can present tactile sensations such as roughness and smoothness (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-314369 Summary of the Invention [Problem to be solved by the invention]

[0005] In principle, tactile sensations in the high-frequency range are generated by placing a pair of piezoelectric actuators on both ends of a panel and generating a standing wave on the panel, which creates a floating sensation in the fingertip. Therefore, at least two piezoelectric actuators are required for one panel.

[0006] In view of the above circumstances, an object of the present invention is to provide a vibration generator and an electronic device that can provide a new tactile sensation using a single piezoelectric actuator. [Means for solving the problem]

[0007] In order to achieve the above object, a vibration generator according to one aspect of the present invention includes a plate-like member and a piezoelectric actuator. The plate-like member has a first main surface and a second main surface opposite to the first main surface. side The second main surface The longitudinal direction is in a first direction, and the transverse direction is in a second direction perpendicular to the first direction. A base and provided on the first main surface, including a central region of the first main surface, and arranged side by side in the first direction and the second direction; protruding from the first main surface death A plurality of protrusions whose vertices are located on a predetermined plane; support portions connected to both ends of the base portion in the first direction and supporting the base portion such that a space is formed on the second main surface; Equipped with. The piezoelectric actuator is Located within the above space It is bonded to the second main surface.

[0008] The vibration generating device may further include a driving unit that outputs to the piezoelectric actuator a driving signal having a waveform obtained by amplitude-modulating a sine wave in a high-frequency region having a frequency of 20 kHz to 100 kHz using a signal wave in a low-frequency region having a frequency of 1 Hz to 250 Hz as a modulating wave.

[0009] The base, the plurality of protrusions, and the support may be formed from a material having a Young's modulus of 50 MPa or more and 300 MPa or less.

[0010] The tips of the plurality of protrusions may be hemispherical.

[0011] In order to achieve the above object, an electronic device according to an embodiment of the present invention includes a vibration generator and a vibrating body. The vibration generator has a first main surface and a surface opposite to the first main surface. side and a second main surface of A flat plate-shaped plate having a longitudinal direction in a first direction and a transverse direction in a second direction perpendicular to the first direction. A base and provided on the first main surface, including a central region of the first main surface, and arranged side by side in the first direction and the second direction; protruding from the first main surface death A plurality of protrusions whose vertices are located on a predetermined plane; support portions connected to both ends of the base portion in the first direction and supporting the base portion such that a space is formed on the second main surface; a plate-like member comprising: Located within the above space and a piezoelectric actuator bonded to the second main surface. The vibration body has the plurality of protrusions joined thereto. [Effects of the Invention]

[0012] As described above, according to the present invention, it is possible to provide a vibration generator and an electronic device that can present a new tactile sensation using a single piezoelectric actuator. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram of a vibration generator according to an embodiment of the present invention. [Figure 2] 10 is a side view of a tactile sense expansion member of the vibration generating mechanism provided in the vibration generating device. FIG. [Figure 3] FIG. 2 is a perspective view of the tactile expansion member. [Figure 4] FIG. 2 is a perspective view of the tactile expansion member. [Figure 5] FIG. 2 is a side view of the tactile expansion member. [Figure 6] FIG. 10 is a plan view of the tactile expansion member. [Figure 7] FIG. 2 is a perspective view of the vibration generating mechanism. [Figure 8] FIG. 2 is a cross-sectional view of the vibration generating mechanism. [Figure 9] This is a high-frequency waveform generated by a driving unit included in the vibration generator. [Figure 10] This is a low frequency waveform generated by the drive unit. [Figure 11] This is the amplitude modulated waveform generated by the drive unit. [Figure 12] 12 is an enlarged waveform of the amplitude modulated wave in FIG. 11. [Figure 13] This is an amplitude modulated waveform (voltage waveform only) generated by the driving unit. [Figure 14] 14 is an enlarged waveform of the amplitude modulated wave in FIG. 13. [Figure 15] FIG. 2 is a schematic diagram showing the amplitude of an amplitude-modulated wave. [Figure 16] FIG. 2 is a perspective view of a vibration generating mechanism joined to a vibrating body according to an embodiment of the present invention. [Figure 17] FIG. 2 is a perspective view of a vibration generating mechanism joined to the vibrating body. [Figure 18]FIG. 10 is a plan view of a tactile sense expansion member according to a modified example of the present invention. [Figure 19] FIG. 2 is a side view of the tactile expansion member. [Figure 20] FIG. 10 is a side view of a tactile extension member according to a modified example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] An electromagnetic exciter according to an embodiment of the present invention will be described.

[0015] [Configuration of vibration generator] 1 is a schematic diagram of a vibration generator 100 according to this embodiment. As shown in the figure, the vibration generator 100 includes a vibration generating mechanism 101 and a driving unit 102. The vibration generating mechanism 101 includes a tactile sense extension member 103 and a piezoelectric actuator 104.

[0016] The tactile sense extension member 103 is a plate-shaped member that generates vibrations using a piezoelectric actuator 104 to extend the sense of touch. FIG. 2 is a side view of the tactile sense extension member 103, and FIGS. 3 and 4 are perspective views of the tactile sense extension member 103. As shown in FIG. 2, the tactile sense extension member 103 includes a base 111, protrusions 112, and a support portion 113. The base 111 is a flat plate-shaped portion and includes a first main surface 111a and a second main surface 111b. The first main surface 111a and the second main surface 111b are opposite main surfaces. Hereinafter, the plane parallel to the first main surface 111a and the second main surface 111b will be referred to as the XY plane. FIG. 3 is a perspective view of the tactile sense extension member 103 as viewed from the first main surface 111a side, and FIG. 4 is a perspective view of the tactile sense extension member 103 as viewed from the second main surface 111b side.

[0017] The protrusions 112 are protrusions that protrude from the first main surface 111a. As shown in Figures 2 and 3, the tactile sense extension member 103 has multiple protrusions 112. Each protrusion 112 has a cylindrical shape. Figure 5 is a side view of a portion of the tactile sense extension member 103, and Figure 6 is a plan view of a portion of the tactile sense extension member 103. As shown in these figures, the multiple protrusions 112 have the same height H from the first main surface 111a, and their vertices are located on a plane S. The plane S is a plane (XY plane) parallel to the first main surface 111a. The number, height H, width W, and spacing P of the protrusions 112 are not particularly limited, but it is preferable that the height H be 1 mm or more and the width W be 1 mm or more.

[0018] The support parts 113 are provided at both ends of the base part 111 in the longitudinal direction (X direction), one at a time, and are used to fix the tactile sense extension member 103. The support parts 113 are provided with through holes 113a, through which fixing members such as screws are inserted. The through holes 113a are not necessarily provided. The support parts 113 are bent toward the second main surface 111b with respect to the base part 111, as shown in FIG. 2, and form a space for vibration of the piezoelectric actuator 104.

[0019] Although there are no particular limitations on the material of the tactile sense extension member 103, a hard resin material with a Young's modulus of 50 MPa to 300 MPa is suitable, such as polyphenylene sulfide. Also, by insulating the piezoelectric actuator 104 from the tactile sense extension member 103, a metal material can be used as the material for the tactile sense extension member 103.

[0020] The piezoelectric actuator 104 is bonded to the tactile sense extension member 103 and generates vibrations. FIG. 7 is a perspective view of the vibration generating mechanism 101, and FIG. 8 is a cross-sectional view of the vibration generating mechanism 101. As shown in these figures, the piezoelectric actuator 104 is bonded to the second main surface 111b of the tactile sense extension member 103. This bonding can be achieved, for example, by adhesive. The piezoelectric actuator 104 has a positive electrode, a negative electrode, and a piezoelectric material layer. When a voltage is applied between the positive electrode and the negative electrode, the piezoelectric material layer deforms due to the inverse piezoelectric effect, generating vibrations. The piezoelectric actuator 104 may have a layered structure in which positive electrodes and negative electrodes are alternately stacked with piezoelectric material layers interposed therebetween, or it may have another structure.

[0021] The driving unit 102 outputs a driving signal to the piezoelectric actuator 104. The driving unit 102 is connected to the positive and negative electrodes of the piezoelectric actuator 104, and outputs a voltage waveform (described later) between the positive and negative electrodes as a driving signal. The driving unit 102 is, for example, an amplifier.

[0022] The vibration generator 100 has the above-described configuration. The vibration generator 100 can be installed in various electronic devices such as smartphones and haptic function devices.

[0023] [About the drive signal] The following describes the waveform of the drive signal output from the drive unit 102 to the piezoelectric actuator 104. Note that, for convenience, the signal wave in the low frequency range is assumed to be a sine wave in the following description, but is not limited to this.

[0024] Fig. 9 shows voltage and current waveforms that are sine waves in the high frequency range, with frequencies between 20 kHz and 100 kHz. When the voltage waveform shown in Fig. 9 is applied as a drive signal from driving unit 102 to piezoelectric actuator 104, a current having the current waveform shown in Fig. 9 flows. Vibrations in the high frequency range between 20 kHz and 100 kHz are vibrations that cause the floating phenomenon.

[0025] Figure 10 shows voltage waveforms and current waveforms that are sine waves in the low-frequency range, with frequencies between 1 Hz and 250 Hz. When the voltage waveform shown in Figure 10 is applied as a drive signal from drive unit 102 to piezoelectric actuator 104, a current having the current waveform shown in Figure 10 flows. Vibrations in the low-frequency range between 1 Hz and 250 Hz are vibrations that can be sensitively sensed by receptors in the human skin, such as Meissner's corpuscles and Pacinian corpuscles.

[0026] Fig. 11 shows voltage and current waveforms having an amplitude-modulated waveform in which a low-frequency sine wave (signal wave) is used as a modulating wave and a high-frequency sine wave is amplitude-modulated by this modulating wave. Fig. 12 is an enlarged view of Fig. 11. When the voltage waveform shown in Fig. 11 is applied as a drive signal from driving unit 102 to piezoelectric actuator 104, a current having the current waveform shown in Fig. 11 flows.

[0027] Figure 13 shows only the voltage waveform of Figure 11, and Figure 14 shows only the voltage waveform of Figure 12. In Figures 13 and 14, the wave with a small wavelength indicated by W1 is a sine wave in the high frequency region, and the wave with a large wavelength indicated by W2 is a sine wave in the low frequency region. Hereinafter, the sine wave in the high frequency region will be referred to as high frequency W1, and the sine wave in the low frequency region will be referred to as low frequency W2.

[0028] 13 and 14, the low frequency W2 is formed by changing the amplitude of the high frequency W1, that is, the waveforms shown in Figures 13 and 14 are amplitude modulated waves with the high frequency W1 as the carrier wave and the low frequency W2 as the modulating wave. Note that the high frequency W1 has a frequency of 20 kHz or more and 100 kHz or less, and the low frequency W2 has a frequency of 1 Hz or more and 250 Hz or less.

[0029] The voltage gain of the high frequency W1 is preferably between -10 dB and 0 dB, and the voltage gain of the low frequency W2 is preferably between -6 dB and 0 dB. Figure 15 is a schematic diagram showing the relationship between the waveform of an amplitude-modulated wave and the voltage gain. As shown in the figure, if the amplitude of the "peak" of the amplitude-modulated wave is amplitude a and the amplitude of the "valley" is amplitude b, then the modulation depth m is expressed by the following (Equation 1). As shown in the following (Equation 1), the smaller the amplitude b is relative to the amplitude a, the greater the modulation depth m.

[0030] m=(ab) / (a+b) (Equation 1)

[0031] In Figure 13, as shown by the white arrow in Figure 13, increasing the voltage gain of low frequency W2 deepens the "valley bottom" of low frequency W2, and when the voltage gain of low frequency W2 is 0 dB, the amplitude of the "valley bottom" is minimized. Furthermore, lowering the voltage gain of low frequency W2, approaching -6 dB, makes the "valley bottom" of low frequency W2 shallower and increases its amplitude. Furthermore, lowering the voltage gain of low frequency W2, approaching -10 dB, makes the amplitude b of the "valley bottom" of low frequency W2 equal to the amplitude of the "peak," and no "valley" is formed.

[0032] In this embodiment, the voltage gains of the high frequency W1 and the low frequency W2 are adjusted to a range in which a "valley" is formed. Specifically, the voltage gain of the high frequency W1 is preferably between -10 dB and 0 dB, and the voltage gain of the low frequency W2 is preferably between -6 dB and 0 dB. Furthermore, the voltage gain of the high frequency W1 is more preferably -10 dB, and the voltage gain of the low frequency W2 is more preferably 0 dB.

[0033] 13 to the piezoelectric actuator 104, the piezoelectric actuator 104 vibrates, thereby vibrating the tactile sense extension member 103. This amplitude-modulated wave is obtained by amplitude-modulating a high frequency W1 that causes a levitation phenomenon with a low frequency W2 that is sensitive to receptors in the human skin, such as Meissner's corpuscles and Pacinian corpuscles. Therefore, when a user places their finger in contact with the protrusion 112, a delicate tactile sensation can be presented to the user's finger in a realistic manner. Furthermore, the tactile sensation can be enhanced by moving the finger while it is in contact with the protrusion 112.

[0034] Furthermore, because the high frequency W1 is amplitude modulated, the average current of the entire waveform is smaller than when it is not amplitude modulated, making it possible to reduce power consumption and heat generation. In particular, when the voltage gain of the high frequency W1 is set to between -10 dB and 0 dB and the voltage gain of the low frequency W2 is set to between -6 dB and 0 dB, a "valley" (white arrow in Figure 13) is formed, making it possible to reduce power consumption and heat generation. Furthermore, when the voltage gain of the high frequency W1 is set to -10 dB and the voltage gain of the low frequency W2 is set to 0 dB, the "valley" becomes the deepest, making it possible to minimize power consumption and heat generation.

[0035] [About joining to the vibrating body] The vibration generating mechanism 101 may be used alone, or may be bonded to a vibrating body to vibrate the vibrating body. FIG. 16 is a perspective view showing the vibration generating mechanism 101 bonded to a vibrating body 151, and FIG. 17 is a cross-sectional view showing the vibration generating mechanism 101 bonded to the vibrating body 151. As shown in these figures, the vibration generating mechanism 101 may be bonded to the vibrating body 151 at the tip of the protrusion 112 of the tactile sense extension member 103. This bonding can be performed, for example, by adhesive. The vibrating body 151 can be a plate-shaped member made of glass, plastic, or other material, such as a display panel or the housing of an electronic device. The shape and size of the vibrating body 151 are not particularly limited.

[0036] In this configuration, when the driving unit 102 outputs a driving signal having an amplitude-modulated voltage waveform shown in Fig. 13 to the piezoelectric actuator 104, a standing wave is formed in the vibrating body 151 by the vibration generating mechanism 101 at high frequency W1, causing a levitation phenomenon. Furthermore, a vibration that stimulates receptors such as Meissner's corpuscles and Pacinian corpuscles is generated in the vibrating body 151 by low frequency W2.

[0037] As a result, when the user brings their finger into contact with the vibrator 151, the low frequency W2 sensitively presents a tactile sensation to the finger, and when the user presses their finger against the vibrator 151, they are subjected to a squeeze effect due to the levitation phenomenon as well as strong low frequency vibrations, allowing them to feel an unprecedented tactile sensation. Also, when a sine wave in the high frequency range as shown in Fig. 9 is used as the drive signal, abnormal noise may occur between the user's finger and the vibrator 151, but the amplitude modulated wave shown in Fig. 13 makes it possible to prevent such abnormal noise from occurring.

[0038] Although two vibration generating mechanisms 101 are joined to the vibrating body 151 in FIG. 16, the number of vibration generating mechanisms 101 joined to the vibrating body 151 may be one or three or more.

[0039] [Variations] The tactile sense extension member 103 has multiple protrusions 112, but the shape of the protrusions 112 is not limited to the one described above. Figure 18 is a plan view of a tactile sense extension member 103 having another shape, and Figure 19 is a side view of this tactile sense extension member 103. As shown in these figures, the protrusions 112 have a rectangular prism shape and may be arranged at a higher density. Figure 20 is a schematic diagram of protrusions 112 with hemispherical tips. As shown in the figure, the tips of the protrusions 112 are not limited to a flat shape and may also be hemispherical. The shape of the protrusions 112 is not particularly limited, and it is sufficient if the tips of the multiple protrusions 112 are positioned on the plane S. [Explanation of symbols]

[0040] 100...Vibration generator 101...Vibration generating mechanism 102...Drive unit 103...Tactile extension member 104...Piezoelectric actuator 111...Base 112...Protrusion 113...Support part 151...Vibration body

Claims

1. a plate-like member including: a flat base portion having a first main surface and a second main surface opposite to the first main surface, the base portion having a longitudinal direction in a first direction and a lateral direction in a second direction perpendicular to the first direction; a plurality of protrusions provided on the first main surface in the first direction and the second direction, including a central region of the first main surface, the protrusions protruding from the first main surface and having apexes located on a predetermined plane; and support portions connected to both ends of the base in the first direction and supporting the base such that a space is formed on the second main surface; a piezoelectric actuator located within the space and bonded to the second main surface; A vibration generating device comprising:

2. The vibration generating device according to claim 1, The piezoelectric actuator further includes a drive unit that outputs a drive signal having a waveform obtained by amplitude-modulating a sine wave in a high frequency range of 20 kHz to 100 kHz with a signal wave in a low frequency range of 1 Hz to 250 Hz as a modulating wave. Vibration generator.

3. 3. The vibration generator according to claim 1, The base portion, the plurality of protrusions, and the support portion are formed of a material having a Young's modulus of 50 MPa or more and 300 MPa or less. Vibration generator.

4. 3. The vibration generator according to claim 1, The tips of the plurality of protrusions are hemispherical in shape. Vibration generator.

5. a vibration generator comprising: a plate-like member including a flat base having a first main surface and a second main surface opposite to the first main surface, the base having a longitudinal direction in a first direction and a lateral direction in a second direction perpendicular to the first direction; a plurality of protrusions provided on the first main surface in a line in the first direction and the second direction including a central region of the first main surface, the protrusions protruding from the first main surface and having apexes located on a predetermined plane; and support portions connected to both ends of the base in the first direction and supporting the base such that a space is formed on the second main surface; and a piezoelectric actuator located in the space and bonded to the second main surface; a vibrating body to which the plurality of protrusions are joined; An electronic device comprising:

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