JP7561503B2 - Vibration generating device and electronic device - Google Patents

Description

The present invention relates to a vibration generating device and electronic device for presenting a tactile sensation through vibration.

Touch panels in smartphones, car navigation systems, and other devices use a technology called force feedback that notifies users of input by vibrating. In recent years, haptic technology has been investigated that goes beyond notifications to provide a variety of vibrations to express the feel of displayed objects and identify operating positions.

As a haptic technology, a piezoelectric actuator can be attached to a panel and vibrations in the ultrasonic band can be used to generate standing waves on the panel surface. When the user touches the surface with their finger, they can feel a sense of touch. By changing the signal pattern, a wide variety of tactile sensations can be expressed.

However, when touching the surface of a panel that produces such a tactile sensation, an abnormal sound (hereinafter, contact sound) may be generated due to the contact between the finger and the panel. In response to this, Patent Document 1 proposes a method of generating a suppression sound with a higher frequency than the generated sound, thereby making the contact sound of the finger sound quieter due to the two-sound suppression effect.

JP 2018-194967 A

However, the technology described in Patent Document 1 does not suppress the occurrence of contact noise itself.

In view of the above, the object of the present invention is to provide a vibration generating device and electronic device that can present a tactile sensation while preventing the generation of contact noise.

In order to achieve the above object, a vibration generator according to one aspect of the present invention includes a vibrating body, a piezoelectric actuator, and a driving device.
The vibrating body has a first main surface and a second main surface opposite to the first main surface.
The piezoelectric actuator is bonded to the second main surface.
The driving device supplies the piezoelectric actuator with a driving signal having a frequency of 60 kHz or more.
The sound pressure characteristics of the vibrator show a peak at 1/4 of the frequency of the drive signal when a person's finger is in contact with the vibrator, and show a peak at a frequency higher than 1/4 of the frequency of the drive signal when a person's finger is not in contact with the vibrator .

With this configuration, the 1/4 frequency vibration that causes contact noise between a finger and the vibrator becomes a vibration of 15 kHz or higher, which is beyond the human audible range, making it possible to prevent the generation of contact noise.

The vibrating body may be made of glass or a resin material with a bending elastic modulus of 3.0 GPa or less.

In order to achieve the above object, an electronic device according to an embodiment of the present invention includes a vibration generating device.
The vibration generating device includes a vibrating body having a first main surface and a second main surface opposite the first main surface, a piezoelectric actuator joined to the second main surface, and a driving device that supplies a driving signal having a frequency of 60 kHz or more to the piezoelectric actuator.
The sound pressure characteristics of the vibrator show a peak at 1/4 of the frequency of the drive signal when a person's finger is in contact with the vibrator, and show a peak at a frequency higher than 1/4 of the frequency of the drive signal when a person's finger is not in contact with the vibrator .

As described above, the present invention makes it possible to provide a vibration generating device and electronic device that can present a tactile sensation while preventing the generation of contact noise.

1 is a schematic diagram of a vibration generating device according to an embodiment of the present invention. FIG. 2 is a perspective view of the vibration generating device. FIG. 2 is a side view of the vibration generating device. 4 is a graph showing sound pressure characteristics of the vibrating body. 4 is a graph showing the vibration displacement of the vibrating body.

A vibration generating device according to an embodiment of the present invention will be described. Note that in each of the following figures, the X direction, Y direction, and Z direction are defined as three mutually orthogonal directions.

[Configuration of vibration generating device]
Fig. 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 vibrating body 101, a piezoelectric actuator 102, and a driving device 103. Fig. 2 is a perspective view of the vibration generator 100, and Fig. 3 is a side view of the vibration generator 100. Note that the driving device 103 is omitted from Figs. 2 and 3.

The vibrating body 101 presents a tactile sensation to a user who touches the vibrating body 101. The vibrating body 101 can be a plate-shaped member made of glass or a resin material, such as a liquid crystal panel or a housing for an electronic device. When the vibrating body 101 is made of a resin material, a resin material with a bending modulus of elasticity of 3.0 GPa or less is preferable. There are no particular limitations on the shape or size of the vibrating body 101. As shown in Figures 2 and 3, one of the main surfaces of the vibrating body 101 is a first main surface 101a, and the main surface opposite the first main surface 101a is a second main surface.

The piezoelectric actuator 102 is bonded to the second main surface 101b of the vibrating body 101 and generates vibration. The piezoelectric actuator 102 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 vibration. Figure 1 shows a positive electrode terminal 102a connected to the positive electrode and a negative electrode terminal 102b connected to the negative electrode.

The positive electrode terminal 102a is connected to a positive electrode wire 104, and the negative electrode terminal 102b is connected to a negative electrode wire 105. As shown in FIG. 1, the positive electrode wire 104 and the negative electrode wire 105 are connected to a driving device 103, and when a driving signal is supplied from the driving device 103, vibration occurs in the piezoelectric actuator 102.

The piezoelectric actuator 102 may have a laminated structure in which positive and negative electrodes are alternately stacked with piezoelectric material layers interposed therebetween, or may have another structure. The piezoelectric actuator 102 may be bonded to the second main surface 101b with an epoxy resin or the like. Two or more piezoelectric actuators 102 may be bonded to the second main surface.

As shown in FIG. 3, the vibration generating device 100 is used with a user's finger F in contact with the first main surface 101a. At this time, the piezoelectric actuator 102 bonded to the second main surface 101b generates vibrations, allowing the user to sense a tactile sensation with the finger F.

The driving device 103 is, for example, an amplifier, and is connected to the piezoelectric actuator 102 via the positive wiring 104 and the negative wiring 105, and supplies a driving signal to the piezoelectric actuator 102. The frequency of the driving signal is preferably 60 kHz or higher.

[About the drive signal]
4 is a graph showing the sound pressure characteristics of the vibrating body 101 when the finger F does not contact the vibrating body 101 and when it contacts the vibrating body 101. As shown in the figure, when the finger F contacts the vibrating body 101, peaks exist at 1/2 and 1/4 of the frequency of the drive signal, and the peak at the 1/4 frequency is heard as a contact sound.

Figure 5 is a graph showing the vibration displacement of the vibrating body 101 when a finger F touches the vibrating body 101. As with the sound pressure characteristics, the vibration of the vibrating body 101 has peaks at 1/2 and 1/4 of the frequency of the drive signal, and the vibrating body 101 vibrates at those frequencies when touched by a finger.

Here, when the driving device 103 generates a driving signal of 60 kHz or more as described above, the 1/4 frequency vibration generated in the vibrating body 101 is 15 kHz or more. Since vibrations of 15 kHz or more are outside the human audible range, the contact sound becomes inaudible.

In this way, in the vibration generating device 100, the driving device 103 supplies driving vibrations of 60 kHz or more to the piezoelectric actuator, making it possible to present a tactile sensation to the user while preventing the generation of contact noise.

The vibration generating device 100 has the above-described configuration. The vibration generating device 100 can be installed in various electronic devices such as smartphones and haptic function devices.

100: Vibration generating device 101: Vibration body 102: Piezoelectric actuator 103: Driving device

Claims (3)

a vibrating body having a first main surface and a second main surface opposite to the first main surface;
a piezoelectric actuator bonded to the second main surface;
A driving device that supplies a driving signal having a frequency of 60 kHz or more to the piezoelectric actuator,
The sound pressure characteristic of the vibrator shows a peak at 1/4 of the frequency of the drive signal when a person's finger is in contact with the vibrator, and shows a peak at a frequency higher than 1/4 of the frequency of the drive signal when a person's finger is not in contact with the vibrator.
Vibration generator. The vibration generating device according to claim 1 ,
The vibration generating device, wherein the vibrating body is made of glass or a resin material having a bending elastic modulus of 3.0 GPa or less. a vibration generating device including a vibrating body having a first main surface and a second main surface opposite to the first main surface, a piezoelectric actuator bonded to the second main surface, and a driving device that supplies a driving signal having a frequency of 60 kHz or more to the piezoelectric actuator,
The sound pressure characteristic of the vibrator shows a peak at 1/4 of the frequency of the drive signal when a person's finger is in contact with the vibrator, and shows a peak at a frequency higher than 1/4 of the frequency of the drive signal when a person's finger is not in contact with the vibrator.
Electronic devices.

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