JP2021137735A - Vibration generator and electronic apparatus - Google Patents

Abstract

To provide a vibration generator and an electronic apparatus capable of presenting a tactile feeling while preventing the generation of contact noise.SOLUTION: A vibration generator is equipped with a vibrator, and a piezoelectric actuator. The vibrator has a first main surface, and a second main surface on the opposite side to the first main surface. The piezoelectric actuator is joined with the second main surface. On the first main surface, a plurality of recessed/projections are formed at equal intervals.SELECTED DRAWING: Figure 4

Description

The present invention relates to a vibration generator and an electronic device related to tactile presentation by vibration.

Touch panels such as smartphones and car navigation systems use a technology (force feedback) that vibrates to notify that an input has been made. Further, in recent years, not only notification but also tactile technology for expressing the feel of a displayed object and recognizing an operation position by giving various variations to the vibration of the panel has been studied.

As a tactile technique, a piezoelectric actuator can be attached to a panel to generate vibration in the ultrasonic band to generate a standing wave on the panel surface. When the surface is touched with a finger or the like, the user can feel the tactile sensation. By changing the signal pattern, it is possible to express various variations of tactile sensation.

However, when a finger touches the surface of the panel that generates such a tactile sensation, an abnormal noise (hereinafter referred to as a contact sound) due to the contact between the finger and the panel may be derived. On the other hand, Patent Document 1 proposes a method of generating a suppressed sound having a frequency higher than the generated sound to make the contact sound of the upper finger audibly felt smaller by the two-sound suppressing effect. .. Further, Patent Document 2 presents a method of reducing finger contact noise by roughening the surface roughness of the panel surface.

Japanese Unexamined Patent Publication No. 2018-194967 JP-A-2019-16111

However, in the technique described in Patent Document 1, the generation of contact sound itself is not suppressed. Further, in the technique described in Patent Document 2, the continuity of surface irregularities is not mentioned.

In view of the above circumstances, an object of the present invention is to provide a vibration generator and an electronic device capable of presenting a tactile sensation while preventing the generation of contact sounds.

In order to achieve the above object, the vibration generator according to one embodiment of the present invention includes a vibrating body and a piezoelectric actuator.
The vibrating body has a first main surface and a second main surface opposite to the first main surface.
The piezoelectric actuator is joined to the second main surface.
A plurality of irregularities are formed at equal intervals on the first main surface.

According to this configuration, since the irregularities are formed on the first main surface of the vibrating body at equal intervals, the contact between the user's finger touching the first main surface and the first main surface does not continue. It is possible to prevent the generation of contact sound while presenting the tactile sensation to the user's finger.

The plurality of irregularities may have a depth of 0.01 mm or more and 0.1 mm or less and a width of 1 mm or more and 10 mm or less.

The plurality of irregularities are formed by alternately forming a plurality of concave portions extending along a first direction parallel to the first main surface and a plurality of convex portions extending along the first direction. May be good.

The plurality of irregularities are further parallel to the first main surface and extend along a second direction different from the first direction, and extend along the second direction. A plurality of convex portions may be formed alternately.

The plurality of irregularities may have a sinusoidal cross-sectional shape on a plane perpendicular to the first direction.

The vibrating body may be made of glass or a resin material having a flexural modulus of 3.0 GPa or more.

The vibrating body is composed of a base material and a film attached to the surface of the base material.
The unevenness may be formed on the surface of the film.

The vibrating body may have light transmission.

In order to achieve the above object, the electronic device according to one embodiment of the present invention includes a vibration generator.
The vibration generator includes a vibrating body having one main surface, a second main surface opposite to the first main surface, and a piezoelectric actuator joined to the second main surface. On the first main surface, a plurality of irregularities are formed at equal intervals.

As described above, according to the present invention, it is possible to provide a vibration generator and an electronic device capable of presenting a tactile sensation while preventing the generation of contact sound.

It is a schematic diagram of the vibration generator which concerns on embodiment of this invention. It is a perspective view of the said vibration generator. It is a side view of the said vibration generator. It is a perspective view of the vibrating body included in the said vibration generator. It is a top view of the said vibrating body. It is a side view of the said vibrating body. It is a graph which shows the sound pressure characteristic of the vibrating body which concerns on a comparative example. It is a graph which shows the vibration displacement amount of the vibrating body which concerns on a comparative example. It is a graph which shows the sound pressure characteristic of the vibrating body provided in the vibration generator which concerns on embodiment of this invention. It is a graph which shows the vibration displacement amount of the said vibrating body. It is a top view of the vibrating body having another structure which concerns on embodiment of this invention. It is a top view of the vibrating body having another structure which concerns on embodiment of this invention. It is a side view of the vibrating body having another structure which concerns on embodiment of this invention. It is a side view of the vibrating body having another structure which concerns on embodiment of this invention. It is a side view of the vibrating body having another structure which concerns on embodiment of this invention. It is a perspective view of the vibrating body provided with unevenness along two directions which concerns on embodiment of this invention. It is a top view of the said vibrating body. It is a top view of the vibrating body having another structure which concerns on embodiment of this invention. It is a top view of the vibrating body having another structure which concerns on embodiment of this invention.

The vibration generator according to the embodiment of the present invention will be described. In each of the following figures, the X direction, the Y direction, and the Z direction are three directions orthogonal to each other.

[Vibration generator configuration]
FIG. 1 is a schematic view of the vibration generator 100 according to the present 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 drive device 103 is not shown in FIGS. 2 and 3.

The vibrating body 101 presents a tactile sensation to the user who touches the vibrating body 101. The vibrating body 101 can be a plate-shaped member made of glass or a resin material, for example, a liquid crystal panel, a housing of an electronic device, or the like. When the vibrating body 101 is made of a resin material, a resin material having a flexural modulus of 3.0 GPa or more is suitable. The shape and size of the vibrating body 101 are not particularly limited. As shown in FIGS. 2 and 3, one main surface of the vibrating body 101 is designated as the first main surface 101a, and the main surface opposite to the first main surface 101a is designated as the second main surface. The first main surface 101a is formed with irregularities, which will be described later.

The piezoelectric actuator 102 is joined to the second main surface 101b of the vibrating body 101 to generate vibration. The piezoelectric actuator 102 includes a positive electrode, a negative electrode, and a piezoelectric material layer, and when a voltage is applied between the positive electrode and the negative electrode, the piezoelectric material layer is deformed by the inverse piezoelectric effect, and vibration is generated. FIG. 1 shows a positive electrode terminal 102a connected to a positive electrode and a negative electrode terminal 102b connected to a negative electrode.

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

The piezoelectric actuator 102 may have a laminated structure in which positive electrodes and negative electrodes are alternately laminated via a piezoelectric material layer, or may have another structure. The piezoelectric actuator 102 can be joined to the second main surface 101b with an epoxy resin or the like. Further, two or more piezoelectric actuators 102 may be joined to the second main surface.

As shown in FIG. 3, in the vibration generator 100, the user's finger F is used in contact with the first main surface 101a. At this time, the piezoelectric actuator 102 joined to the second main surface 101b generates vibration, so that the user can sense the tactile sensation of the finger F.

The drive device 103 is, for example, an amplifier, which is connected to the piezoelectric actuator 102 via the positive electrode wiring 104 and the negative electrode wiring 105, and supplies a drive signal to the piezoelectric actuator 102. The frequency of the drive signal is not particularly limited, but 60 kHz or higher is preferable.

[About the vibrating body]
Regular irregularities are formed on the first main surface 101a of the vibrating body 101. FIG. 4 is a perspective view of the vibrating body 101, showing the unevenness 101c formed on the first main surface 101a. In addition, in FIGS. 1 to 3, the unevenness 101c is not shown. FIG. 5 is a plan view showing the first main surface 101a. FIG. 6 is a cross-sectional view of the vibrating body 101, and is a cross-sectional view taken along the line AA shown in FIGS. 4 and 5.

As shown in these figures, the first main surface 101a is provided with a plurality of concave portions 101d and a plurality of convex portions 101e. Each recess 101d extends along one direction (X direction) parallel to the first main surface 101a when viewed from a direction perpendicular to the first main surface 101a (Z direction), and each convex portion 101e extends along a direction (X direction) parallel to the first main surface 101a. Stretches along the stretching direction (X direction).

On the first main surface 101a, a plurality of concave portions 101d and a plurality of convex portions 101e are alternately provided to form unevenness 101c. As shown in FIG. 6, the unevenness 101c can have a sinusoidal cross-sectional shape on a plane (YZ plane) perpendicular to the stretching direction of the concave portion 101d and the convex portion 101e.

The distance between the concave portion 101d and the convex portion 101e is equal over the entire unevenness, and as shown in FIG. 6, the convex portion 101e in the direction (Y direction) perpendicular to the extending direction (X direction) of the concave portion 101d and the convex portion 101e. Assuming that the distance between the peaks is the width W, the width W is preferably 1 mm or more and 10 mm or less. Further, assuming that the height difference between the concave portion 101d and the convex portion 101e in the thickness direction (Z direction) of the vibrating body 101 is the depth D, the depth D is preferably 0.01 mm or more and 0.1 mm or less. In addition, in FIG. 4 and FIG. 6, for convenience of illustration, the depth direction (Z direction) of the unevenness 101c is magnified 10 times.

In this way, by forming the unevenness 101c on the first main surface 101a that the user's finger F touches, it is possible to suppress the abnormal noise (contact sound) generated between the finger F and the first main surface 101a. It will be possible. For comparison, FIG. 7 is a graph showing the sound pressure characteristics of a vibrating body having no unevenness, and FIG. 8 is a graph showing the amount of vibration displacement of the vibrating body when a finger comes into contact with the vibrating body.

As shown in FIGS. 7 and 8, when the finger touches the vibrating body, there are vibration peaks at 1/2 and 1/4 of the input frequency to the piezoelectric actuator, and the 1/4 frequency peak is audible. Since it is a frequency range, it can be heard as a contact sound.

On the other hand, FIG. 9 is a graph showing the sound pressure characteristics of the vibrating body 100 provided with the unevenness 101c according to the present embodiment, and FIG. 10 shows the vibration displacement of the vibrating body when the finger F comes into contact with the vibrating body. It is a graph which shows the quantity. As shown in FIGS. 9 and 10, in the vibrating body 100, the peak of the 1/4 frequency can be eliminated, and the contact sound can be reduced. This is because the contact between the finger F touching the first main surface 101a and the first main surface 101a does not continue due to the provision of the unevenness 101c.

Further, in the vibrating body 101, as described above, the concave portions 101d and the convex portions 101e are provided at regular intervals, and when the vibrating body 101 has light transmissivity, the light transmissiveness of the vibrating body 101 is not impaired. It is possible to form unevenness 101c. For example, when the surface of the vibrating body is roughened, the vibrating body becomes frosted glass and it is difficult to maintain the light transmission, but the vibrating body 101 can maintain the light transmission.

Here, as described above, the width W is preferably 1 mm or more and 10 mm or less, but if the width W is less than 1 mm, the visibility via the vibrating body 101 is lowered, and if it exceeds 10 mm, the finger F has unevenness 101c. This is because there is a risk that they will not come into contact with each other. Further, the depth D is preferably 0.01 mm or more and 0.1 mm or less, but if the depth D is less than 0.01 mm, the effect of providing the unevenness 101c cannot be obtained, and if it exceeds 0.1 mm. This is because the unevenness 101c affects the tactile sensation even when there is no vibration.

In the above description, the concave portion 101d and the convex portion 101e are parallel to the lateral direction (X direction) of the vibrating body 101, but the present invention is not limited to this. 11 and 12 are plan views showing other configurations of the unevenness 101c. As shown in FIG. 11, the concave portion 101d and the convex portion 101e may be parallel to the longitudinal direction (Y direction) of the vibrating body 101. Further, as shown in FIG. 12, the concave portion 101d and the convex portion 101e are not parallel to both the lateral direction (X direction) and the longitudinal direction (Y direction) of the vibrating body 101, but extend in the oblique direction. You may.

Further, the unevenness 101c is not limited to the one having a sinusoidal cross-sectional shape. 13 to 15 are cross-sectional views showing another configuration of the unevenness 101c. As shown in FIG. 13, the unevenness 101c can have a rectangular wave shape in the cross-sectional shape of the concave portion 101d and the convex portion 101e on a plane (YZ plane) perpendicular to the stretching direction.

Further, as shown in FIG. 14, the unevenness 101c can have a triangular wave shape in the cross-sectional shape of the concave portion 101d and the convex portion 101e on a plane (YZ plane) perpendicular to the stretching direction. Further, as shown in FIG. 15, the unevenness 101c may be formed by a groove extending in one direction. The cross-sectional shape of the groove is not limited to a triangular shape as shown in FIG. 15, and may be a quadrangular shape, a semicircular shape, or the like.

Further, the unevenness 101c may be such that the concave portion 101d and the convex portion 101e extend in two directions. FIG. 16 is a perspective view of the vibrating body 101 in which the concave portion 101d and the convex portion 101e extend in two directions, and FIG. 17 is a plan view showing the first main surface 101a. The cross-sectional views taken along the line BB shown in FIGS. 16 and 17 are the same as those in FIG.

As shown in FIGS. 16 and 17, the first main surface 101a is provided with a plurality of concave portions 101d and a plurality of convex portions 101e. Each concave portion 101d extends along two directions (X direction and Y direction) parallel to the first main surface 101a when viewed from a direction perpendicular to the first main surface 101a (Z direction), and each convex portion 101e Stretches along the direction in which the recess 101d stretches (X direction and Y direction).

On the first main surface 101a, a plurality of concave portions 101d and a plurality of convex portions 101e are alternately provided to form unevenness 101c. As shown in FIG. 6, the unevenness 101c can have a sinusoidal cross-sectional shape on the planes (YZ plane and XZ plane) perpendicular to the stretching direction of the concave portion 101d and the convex portion 101e. ..

The distance between the concave portion 101d and the convex portion 101e is equal over the entire unevenness, and as shown in FIG. 6, the width W, which is the distance between the peaks of the convex portion 101e in the Y direction, is preferably 1 mm or more and 10 mm or less. Further, also in the X direction, the width W, which is the inter-peak distance of the convex portion 101e, is preferably 1 mm or more and 10 mm or less. This is because if the width W is less than 1 mm, the visibility via the vibrating body 101 is lowered, and if it exceeds 10 mm, the finger F may not come into contact with the unevenness 101c.

Further, the depth D, which is the height difference between the concave portion 101d and the convex portion 101e in the thickness direction (Z direction) of the vibrating body 101, is preferably 0.01 mm or more and 0.1 mm or less. This is because if the depth D is less than 0.01 mm, the effect of providing the unevenness 101c cannot be obtained, and if it exceeds 0.1 mm, the unevenness 101c affects the tactile sensation even when there is no vibration. In FIG. 16, for convenience of illustration, the depth direction (Z direction) of the unevenness 101c is enlarged 10 times.

In this way, the concave portion 101d and the convex portion 101e form the unevenness 101c extending along the two directions (X direction and Y direction) parallel to the first main surface 101a, thereby forming the finger F and the first main surface. It is possible to further suppress the abnormal noise (contact sound) generated between 101a.

By providing the concavo-convex 101c in two directions in the vibrating body 101, the peak of the 1/4 frequency can be eliminated as in the case where the concavo-convex 101c in one direction is provided (see FIGS. 9 and 10), and the contact sound. Can be reduced. Further, in the vibrating body 101, as described above, the concave portions 101d and the convex portions 101e are provided at regular intervals, and when the vibrating body 101 has light transmissivity, the light transmissiveness of the vibrating body 101 is not impaired. It is possible to form unevenness 101c.

In the above description, the concave portion 101d and the convex portion 101e are parallel to the lateral direction (X direction) and the longitudinal direction (Y direction) of the vibrating body 101, but the present invention is not limited to this. 18 and 19 are plan views showing other configurations of the unevenness 101c. As shown in FIG. 18, the concave portion 101d and the convex portion 101e may extend in an oblique direction rather than parallel to the lateral direction (X direction) and the longitudinal direction (Y direction) of the vibrating body 101. Further, as shown in FIG. 19, the two directions in which the concave portion 101d and the convex portion 101e extend do not have to be orthogonal to each other.

Further, the cross-sectional shape of the unevenness 101c is not limited to the sinusoidal shape, and may be a rectangular wave shape or a triangular wave shape as shown in FIGS. 13 and 14, and is formed by grooves as shown in FIG. It is also possible. The cross-sectional shape of the groove is not limited to a triangular shape as shown in FIG. 15, and may be a quadrangular shape, a semicircular shape, or the like.

Further, the vibrating body 101 is made of glass or a resin material and is provided with unevenness 101c, but the present invention is not limited to this. For example, a film made of glass or a resin material having a flexural modulus of 3.0 GPa or more and having a smooth surface and provided with unevenness 101c may be attached.

The vibration generator 100 has the above configuration. The vibration generator 100 can be mounted on various electronic devices such as smartphones and tactile function devices.

100 ... Vibration generator 101 ... Vibrating body 101a ... First main surface 101b ... Second main surface 101c ... Concavo-convex 101d ... Concave 101e ... Convex 102 ... Piezoelectric actuator 103 ... Drive device

Claims (9)

A vibrating body having a first main surface and a second main surface opposite to the first main surface,
A piezoelectric actuator joined to the second main surface is provided.
A vibration generator in which a plurality of irregularities are formed at equal intervals on the first main surface. The vibration generator according to claim 1.
The plurality of irregularities have a depth of 0.01 mm or more and 0.1 mm or less, and a width of 1 mm or more and 10 mm or less.
Vibration generator. The vibration generator according to claim 1 or 2.
The plurality of irregularities are formed with a plurality of concave portions extending along a first direction parallel to the first main surface and a plurality of convex portions extending along the first direction alternately. Vibration generator. The vibration generator according to claim 3.
The plurality of irregularities are further parallel to the first main surface and extend along a second direction different from the first direction, and a plurality of recesses extending along the second direction. A vibration generator in which a plurality of convex portions are alternately formed. The vibration generator according to claim 3 or 4.
The plurality of irregularities are vibration generators having a sinusoidal cross-sectional shape on a plane perpendicular to the first direction. The vibration generator according to any one of claims 1 to 5.
The vibrating body is a vibration generator made of glass or a resin material having a flexural modulus of 3.0 GPa or more. The vibration generator according to any one of claims 1 to 5.
The vibrating body is composed of a base material and a film attached to the surface of the base material.
The unevenness is a vibration generator formed on the surface of the film. The vibration generator according to claim 6 or 7.
The vibrating body is a vibration generator having light transmission. A vibrating body having a first main surface, a second main surface opposite to the first main surface, and a piezoelectric actuator joined to the second main surface are provided, and the first main surface is provided. An electronic device equipped with a vibration generator in which a plurality of irregularities are formed at equal intervals on the main surface.

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