JP2023025412A - Vibration generating device and electronic instrument - Google Patents

Abstract

To provide a vibration generating device that can generate vibrations to express a variety of tactile sense, and an electronic instrument.SOLUTION: A vibration generating device is equipped with a first piezoelectric actuator and a second piezoelectric actuator. The first piezoelectric actuator comprises a first piezoelectric body layer, a first positive internal electrode and a first negative internal electrode opposing to the first positive internal electrode through the first piezoelectric body layer, which when a voltage is applied to a space between the first positive internal electrode and the first negative internal electrode, extends and contracts along a first direction which is parallel to electrode planes of the first positive internal electrode and the first negative internal electrode. The second piezoelectric actuator is laminated on the first piezoelectric actuator and comprises a second piezoelectric body layer, a second positive internal electrode and a second negative internal electrode opposing to the second positive internal electrode through the second piezoelectric body layer, which when a voltage is applied to a space between the second positive internal electrode and the second negative internal electrode, extends and contracts along a second direction which is perpendicular to electrode planes of the second positive internal electrode and the second negative internal electrode and is perpendicular to the first direction.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a vibration generator and an electronic device for presenting a tactile sensation by vibration.

Various actuators are used in tactile functional 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 the force feedback function.

In recent years, tactile technology has become more sophisticated, and in addition to the notification function, technology has been developed that can reproduce tactile sensations such as rough and slippery sensations (see Patent Document 1, for example). Furthermore, liquid crystal panels and the like of mobile devices are required to have surfaces with different tactile sensations for each area.

JP-A-8-314369

Here, the notification function can be realized by vibration in a low frequency range (about 1 to 250 Hz), but the tactile expression such as roughness and smoothness is realized by vibration in a high frequency range (about 20 to 100 kHz). Specifically, the tactile expression is realized by arranging the actuators of the drive source at both ends of the panel and using the levitation phenomenon to the fingertips due to the standing waves formed on the panel. Since the panel vibrates when the same wave is transmitted to the entire panel, only a single tactile expression is possible as a tactile sensation.

In view of the circumstances as described above, it is an object of the present invention to provide a vibration generator and an electronic device capable of expressing various tactile sensations by vibration.

To achieve the above object, a vibration generator according to one aspect of the present invention includes a first piezoelectric actuator and a second piezoelectric actuator.
The first piezoelectric actuator comprises: a first piezoelectric layer made of a piezoelectric material; a first positive internal electrode provided in the first piezoelectric layer; a first negative electrode internal electrode facing the first positive electrode internal electrode via a layer; when a voltage is applied between the first positive electrode internal electrode and the first negative electrode internal electrode, It expands and contracts along the first direction parallel to the electrode surface of the electrode and the first negative internal electrode.
The second piezoelectric actuator is laminated on the first piezoelectric actuator and includes a second piezoelectric layer made of a piezoelectric material, a second positive internal electrode provided in the second piezoelectric layer, and the second piezoelectric body. a second negative internal electrode provided in the layer and opposed to the second positive internal electrode via the second piezoelectric layer, wherein a voltage is applied between the second positive internal electrode and the second negative internal electrode; is applied, the electrode expands and contracts along the second direction perpendicular to the electrode surfaces of the second positive internal electrode and the second negative internal electrode and perpendicular to the first direction.

The first piezoelectric actuator has a first end face perpendicular to the first direction and parallel to the second direction, and a first end face perpendicular to the first direction and parallel to the second direction. A second end surface that is an opposite end surface, a third end surface that is an end surface parallel to the first direction and the second direction, and a third end surface parallel to the first direction and the second direction and the third end surface and a fourth end face that is the opposite end face, the end of the first positive electrode internal electrode is exposed on the first end face, the end of the first negative electrode internal electrode is exposed on the second end face,
The second piezoelectric actuator has a fifth end face perpendicular to the first direction and parallel to the second direction, and a fifth end face perpendicular to the first direction and parallel to the second direction. A sixth end surface that is an end surface on the opposite side, a seventh end surface that is an end surface parallel to the first direction and the second direction, and a seventh end surface parallel to the first direction and the second direction and the seventh end surface and an eighth end face which is the end face on the opposite side, the end of the second positive electrode internal electrode is exposed on the seventh end face, and the end of the second negative electrode internal electrode is exposed on the eighth end face. good too.

The vibration generator includes a plurality of the second piezoelectric actuators arranged in a line along the first direction,
The seventh end surface is a surface continuous with the third end surface,
The eighth end surface may be a surface continuous with the fourth end surface.

The vibration generator is
a positive electrode external electrode provided on the first end surface, the third end surface, and the seventh end surface and electrically connected to the first internal positive electrode and the second internal positive electrode;
A negative electrode external electrode provided on the second end surface, the fourth end surface, and the eighth end surface and electrically connected to the first internal negative electrode and the second internal negative electrode may be further provided.

The vibration generator is
a first positive electrode external electrode provided on the first end surface and electrically connected to the first positive electrode internal electrode;
a first negative electrode external electrode provided on the second end surface and electrically connected to the first negative electrode internal electrode;
a second positive electrode external electrode provided on the seventh end surface and electrically connected to the second positive electrode internal electrode;
A second negative electrode external electrode provided on the eighth end surface and electrically connected to the second negative electrode internal electrode may be further provided.

The vibration generator includes a plurality of the second piezoelectric actuators arranged in two rows along the first direction,
the seventh end face faces the seventh end face of the adjacent second piezoelectric actuator,
The eighth end surface may be a surface continuous with the third end surface and the fourth end surface.

The vibration generator is
a positive electrode external electrode provided on the first end face and the seventh end face and electrically connected to the first positive internal electrode and the second positive internal electrode;
a negative electrode external electrode provided on the second end surface, the third end surface, the fourth end surface, and the eighth end surface and electrically connected to the first internal negative electrode and the second internal negative electrode; You may

The vibration generator is
a first positive electrode external electrode provided on the first end surface and electrically connected to the first positive electrode internal electrode;
a first negative electrode external electrode provided on the second end surface and electrically connected to the first negative electrode internal electrode;
a second positive electrode external electrode provided on the seventh end surface and electrically connected to the second positive electrode internal electrode;
A second negative electrode external electrode provided on the eighth end surface and electrically connected to the second negative electrode internal electrode may be further provided.

The vibration generator is
A driving signal having a waveform obtained by amplitude-modulating a signal wave in a low-frequency region with a frequency of 1 Hz or more and 250 Hz or less as a modulated wave and a sine wave in a high-frequency region with a frequency of 20 kHz or more and 100 kHz or less by the modulated wave. A driving unit for supplying power to the positive external electrode and the negative external electrode may be further provided.

The vibration generator has a signal wave in a low frequency range with a frequency of 1 Hz or more and 250 Hz or less as a modulated wave, and a sine wave in a high frequency range with a frequency of 20 kHz or more and 100 kHz or less, amplitude-modulated by the modulated wave. to the first positive external electrode and the first negative external electrode.
Vibration generator.

To achieve the above object, an electronic device according to one aspect of the present invention includes a first piezoelectric actuator and a second piezoelectric actuator.
The first piezoelectric actuator comprises: a first piezoelectric layer made of a piezoelectric material; a first positive internal electrode provided in the first piezoelectric layer; a first negative electrode internal electrode facing the first positive electrode internal electrode via a layer; when a voltage is applied between the first positive electrode internal electrode and the first negative electrode internal electrode, It expands and contracts along the first direction parallel to the electrode surface of the electrode and the first negative internal electrode.
The second piezoelectric actuator is laminated on the first piezoelectric actuator and includes a second piezoelectric layer made of a piezoelectric material, a second positive internal electrode provided in the second piezoelectric layer, and the second piezoelectric body. a second negative internal electrode provided in the layer and opposed to the second positive internal electrode via the second piezoelectric layer, wherein a voltage is applied between the second positive internal electrode and the second negative internal electrode; is applied, the electrode expands and contracts along the second direction perpendicular to the electrode surfaces of the second positive internal electrode and the second negative internal electrode and perpendicular to the first direction.

As described above, according to the present invention, it is possible to provide a vibration generating device and an electronic device capable of expressing various tactile sensations by vibration.

1 is a perspective view of a vibration generator according to a first embodiment of the invention; FIG. It is an exploded perspective view of the said vibration generator. FIG. 4 is a perspective view of a first piezoelectric actuator included in the vibration generator; 4 is a plan view of the first piezoelectric actuator; FIG. It is a sectional view of the above-mentioned 1st piezo-electric actuator. It is a schematic diagram which shows arrangement|positioning of the 1st positive electrode internal electrode of a said 1st piezoelectric actuator. FIG. 4 is a schematic diagram showing the arrangement of the first negative electrode internal electrodes of the first piezoelectric actuator; It is a perspective view of the 1st end surface of a said 1st piezoelectric actuator. It is a perspective view of the 2nd end surface of the said 1st piezoelectric actuator. It is a schematic diagram which shows operation|movement of a said 1st piezoelectric actuator. FIG. 4 is a perspective view of a second piezoelectric actuator included in the vibration generator; FIG. 4 is a plan view of the second piezoelectric actuator; It is a sectional view of the above-mentioned 2nd piezo-electric actuator. FIG. 5 is a schematic diagram showing the arrangement of a second positive electrode internal electrode of the second piezoelectric actuator; FIG. 4 is a schematic diagram showing the arrangement of second negative internal electrodes of the second piezoelectric actuator. It is a perspective view of the 7th end surface of the said 2nd piezoelectric actuator. FIG. 11 is a perspective view of an eighth end face of the second piezoelectric actuator; It is a schematic diagram which shows operation|movement of a said 2nd piezoelectric actuator. It is a top view of the said vibration generator. It is a top view of the said vibration generator. It is a top view of the said vibration generator. It is a top view of the said vibration generator. It is a top view of the said vibration generator. It is a perspective view of the said vibration generator. It is a perspective view of the said vibration generator. 4 is a perspective view showing a positive external electrode of the vibration generator; FIG. 4 is a perspective view showing a negative external electrode of the vibration generator; FIG. It is a perspective view which shows the 1st positive external electrode and 2nd positive external electrode of the said vibration generator. 4 is a perspective view showing a first negative external electrode and a second negative external electrode of the vibration generator; FIG. It is a high-frequency waveform generated by a drive unit included in the vibration generator. It is a low-frequency waveform generated by the driving section. It is an amplitude modulated wave waveform generated by the driving section. FIG. 33 is an enlarged waveform of the amplitude-modulated wave of FIG. 32. FIG. It is an amplitude-modulated waveform (only voltage waveform) generated by the driving section. It is a waveform which expanded the amplitude modulation wave of FIG. FIG. 4 is a schematic diagram showing the amplitude of an amplitude-modulated wave; It is a perspective view which shows the mounting structure of the said vibration generator. It is a top view which shows the mounting structure of the said vibration generator. FIG. 5 is a perspective view of a vibration generator according to a second embodiment of the present invention; It is an exploded perspective view of the said vibration generator. FIG. 4 is a perspective view of a second piezoelectric actuator included in the vibration generator; FIG. 4 is a plan view of the second piezoelectric actuator; It is a sectional view of the above-mentioned 2nd piezo-electric actuator. FIG. 5 is a schematic diagram showing the arrangement of a second positive electrode internal electrode of the second piezoelectric actuator; FIG. 4 is a schematic diagram showing the arrangement of second negative internal electrodes of the second piezoelectric actuator. It is a perspective view of the 7th end surface of the said 2nd piezoelectric actuator. FIG. 11 is a perspective view of an eighth end face of the second piezoelectric actuator; It is a schematic diagram which shows operation|movement of a said 2nd piezoelectric actuator. It is a top view of the said vibration generator. It is a top view of the said vibration generator. It is a top view of the said vibration generator. It is a top view of the said vibration generator. It is a top view of the said vibration generator. It is a perspective view of the said vibration generator. It is a perspective view of the said vibration generator. 4 is a perspective view showing a positive external electrode of the vibration generator; FIG. 4 is a perspective view showing a negative external electrode of the vibration generator; FIG. It is a perspective view which shows the 1st positive external electrode and 2nd positive external electrode of the said vibration generator. 4 is a perspective view showing a first negative external electrode and a second negative external electrode of the vibration generator; FIG. It is a perspective view which shows the mounting structure of the said vibration generator. It is a top view which shows the mounting structure of the said vibration generator.

(First embodiment)
A vibration generator according to a first embodiment of the present invention will be described.

[Configuration of vibration generator]
FIG. 1 is a perspective view of a vibration generator 100 according to this embodiment, and FIG. 2 is an exploded perspective view of the vibration generator 100. As shown in FIG. In each drawing of the present disclosure, the longitudinal direction of the vibration generator 100 is the X direction, the lateral direction is the Y direction, and the thickness direction is the Z direction.

As shown in FIGS. 1 and 2, the vibration generator 100 includes one first piezoelectric actuator 110 and a plurality of second piezoelectric actuators 120, and the plurality of second piezoelectric actuators 120 are stacked on one first piezoelectric actuator 110. configured.

3 is a perspective view of the first piezoelectric actuator 110, and FIG. 4 is a plan view of the first piezoelectric actuator 110. FIG. As shown in FIGS. 3 and 4, the first piezoelectric actuator 110 has a flat plate shape whose main surface is parallel to the XY plane, with the X direction being the longitudinal direction and the Y direction being the lateral direction. Hereinafter, of the main surfaces of the first piezoelectric actuator 110, the main surface on the second piezoelectric actuator 120 side is referred to as a first main surface 110a, and the main surface opposite to the first main surface 110a is referred to as a second main surface 110b. Further, when the X direction is the “first direction” and the Z direction is the “second direction”, one end face perpendicular to the first direction and parallel to the second direction is the first end face 110c, and the first end face 110c is perpendicular to the first direction. A second end surface 110d is defined as an end surface parallel to the second direction and opposite to the first end surface 110c. Further, one end surface parallel to the first and second directions is a third end surface 110e, and an end surface parallel to the first and second directions and opposite to the third end surface 110e is a fourth end surface 110f.

FIG. 5 is a cross-sectional view of the first piezoelectric actuator 110, taken along line AA in FIG. 4. FIG. As shown in the figure, the first piezoelectric actuator 110 includes a first piezoelectric layer 111 , a first positive internal electrode 112 and a first negative internal electrode 113 . The first piezoelectric layer 111 is made of a piezoelectric material such as PZT (lead zirconate titanate).

The first positive internal electrode 112 is made of a conductive material, is provided in the first piezoelectric layer 111 , and faces the first negative internal electrode 113 with the first piezoelectric layer 111 interposed therebetween. The first positive electrode internal electrode 112 is flat, and when the main surface of the first positive electrode internal electrode 112 is the electrode surface, the electrode surface is parallel to the first main surface 110a and the second main surface 110b (XY plane), That is, it is parallel to the first direction (X direction). Five first positive electrode internal electrodes 112 may be provided as shown in FIG. 5, or four or less or six or more may be provided.

FIG. 6 is a schematic diagram showing the arrangement of the first positive internal electrode 112 in the first piezoelectric actuator 110. As shown in FIG. As shown in the figure, one side of the first positive electrode internal electrode 112 coincides with the first end face 110c, and the other peripheral edges are arranged apart from the second end face 110d, the third end face 110e and the fourth end face 110f. .

The first negative internal electrode 113 is made of a conductive material, is provided in the first piezoelectric layer 111 , and faces the first positive internal electrode 112 with the first piezoelectric layer 111 interposed therebetween. The first negative electrode internal electrode 113 has a flat plate shape. That is, it is parallel to the first direction (X direction). Five first negative electrode internal electrodes 113 may be provided as shown in FIG. 5, or four or less or six or more may be provided.

FIG. 7 is a schematic diagram showing the arrangement of the first negative internal electrode 113 in the first piezoelectric actuator 110. As shown in FIG. As shown in the figure, one side of the first negative electrode internal electrode 113 coincides with the second end surface 110d, and the other peripheral edge is arranged apart from the first end surface 110c, the third end surface 110e and the fourth end surface 110f. .

FIG. 8 is a perspective view showing the first end face 110c. As shown in the figure, the end portion of the first positive internal electrode 112 is exposed on the first end face 110c, and the first negative internal electrode 113 is not exposed. Also, FIG. 9 is a perspective view showing the second end surface 110d. As shown in the figure, the end portion of the first negative internal electrode 113 is exposed on the second end face 110d, and the first positive internal electrode 112 is not exposed.

The first piezoelectric actuator 110 has such a configuration. FIG. 10 is a schematic diagram showing vibration of the first piezoelectric actuator 110. FIG. When a voltage is applied between the first positive electrode internal electrode 112 and the first negative electrode internal electrode 113 , the first piezoelectric actuator 110 moves between the first positive internal electrode 112 and the first negative internal electrode 112 due to the reverse piezoelectric effect in the first piezoelectric layer 111 . It expands and contracts (arrow in the figure) along the first direction (X direction) parallel to the electrode surface of 113 to generate vibration. Such expansion and contraction is called the d31 mode, and the first piezoelectric actuator 110 is a piezoelectric actuator that vibrates in the d31 mode.

11 is a perspective view of the second piezoelectric actuator 120, and FIG. 12 is a plan view of the second piezoelectric actuator 120. FIG. As shown in FIGS. 11 and 12, the second piezoelectric actuator 120 has a flat plate shape with a main surface parallel to the XY plane, with the X direction being the short side and the Y direction being the long side. Hereinafter, of the main surfaces of the second piezoelectric actuator 120, the main surface on the first piezoelectric actuator 110 side will be referred to as a third main surface 120a, and the main surface opposite to the third main surface 120a will be referred to as a fourth main surface 120b. Further, one end surface perpendicular to the first direction (X direction) and parallel to the second direction (Z direction) is defined as a fifth end surface 120c, and the fifth end surface 120c is perpendicular to the first direction, parallel to the second direction, and the fifth end surface 120c. is the sixth end face 120d. Further, one end surface parallel to the first direction and the second direction is defined as a seventh end surface 120e, and an end surface parallel to the first direction and the second direction and opposite to the seventh end surface 120e is defined as an eighth end surface 120f.

FIG. 13 is a cross-sectional view of the second piezoelectric actuator 120, taken along line BB of FIG. 12. FIG. As shown in the figure, the second piezoelectric actuator 120 includes a second piezoelectric layer 121 , a second positive internal electrode 122 and a second negative internal electrode 123 . The second piezoelectric layer 121 is made of a piezoelectric material such as PZT (lead zirconate titanate).

The second positive internal electrode 122 is made of a conductive material, is provided in the second piezoelectric layer 121 , and faces the second negative internal electrode 123 with the second piezoelectric layer 121 interposed therebetween. The second positive electrode internal electrode 122 has a flat plate shape, and when the main surface of the second positive electrode internal electrode 122 is the electrode surface, the electrode surface is parallel to the third main surface 120a and the fourth main surface 120b (XY plane), That is, it is parallel to the first direction (X direction). As for the 2nd positive electrode internal electrode 122, five sheets may be provided as shown in FIG. 13, and four sheets or less or six sheets or more may be provided.

FIG. 14 is a schematic diagram showing the arrangement of the second positive internal electrode 122 in the second piezoelectric actuator 120. As shown in FIG. As shown in the figure, one side of the second positive electrode internal electrode 122 coincides with the seventh end surface 120e, and the other peripheral edge is spaced apart from the fifth end surface 120c, the sixth end surface 120d and the eighth end surface 120f. .

The second negative internal electrode 123 is made of a conductive material, is provided in the second piezoelectric layer 121 , and faces the second positive internal electrode 122 with the second piezoelectric layer 121 interposed therebetween. The second negative electrode internal electrode 123 has a flat plate shape. That is, it is parallel to the first direction (X direction). As for the 2nd negative electrode internal electrode 123, five sheets may be provided as shown in FIG. 13, and four sheets or less or six sheets or more may be provided.

FIG. 15 is a schematic diagram showing the arrangement of the second negative internal electrode 123 in the second piezoelectric actuator 120. As shown in FIG. As shown in the figure, one side of the second negative electrode internal electrode 123 coincides with the eighth end face 120f, and the other peripheral edge is spaced apart from the fifth end face 120c, the sixth end face 120d and the seventh end face 120e. .

FIG. 16 is a perspective view showing the seventh end surface 120e. As shown in the figure, the end of the second positive internal electrode 122 is exposed on the seventh end surface 120e, and the second negative internal electrode 123 is not exposed. Also, FIG. 17 is a perspective view showing the eighth end surface 120f. As shown in the figure, the end of the second negative internal electrode 123 is exposed on the eighth end surface 120f, and the second positive internal electrode 122 is not exposed.

The second piezoelectric actuator 120 has such a configuration. FIG. 18 is a schematic diagram showing vibration of the second piezoelectric actuator 120. FIG. When a voltage is applied between the second positive electrode internal electrode 122 and the second negative electrode internal electrode 123 , the second piezoelectric actuator 120 moves between the second positive electrode internal electrode 122 and the second negative electrode internal electrode 122 due to the reverse piezoelectric effect in the second piezoelectric layer 121 . It expands and contracts (arrow in the figure) along the second direction (Z direction) perpendicular to the electrode surface of 123 to generate vibration. Such expansion and contraction is called the d33 mode, and the second piezoelectric actuator 120 is a piezoelectric actuator that vibrates in the d33 mode.

[Regarding the positional relationship between the first piezoelectric actuator and the second piezoelectric actuator]
The positional relationship between the first piezoelectric actuator 110 and the second piezoelectric actuator 120 will be described below. 19 to 23 are plan views of the vibration generator 100 viewed from various directions. As shown in FIGS. 19 to 21, the second piezoelectric actuator 120 is arranged on the first piezoelectric actuator 110 along the first direction (X direction) with the lateral direction coinciding with the first direction (X direction). Arranged in one row. 22 and 23, the seventh end surface 120e of the second piezoelectric actuator 120 is continuous with the third end surface 110e of the first piezoelectric actuator 110, and the eighth end surface 120f of the second piezoelectric actuator 120 is connected to the third end surface 110e. 1 is continuous with the fourth end surface 110 f of the piezoelectric actuator 110 .

FIG. 24 is a perspective view of the vibration generator 100 viewed from the first end surface 110c and the seventh end surface 120e. As shown in the figure, the first positive internal electrode 112 is exposed on the first end face 110c, and the second positive internal electrode 122 is exposed on the seventh end face 120e. 25 is a perspective view of the vibration generator 100 viewed from the second end surface 110d and the eighth end surface 120f. As shown in the figure, the first negative electrode internal electrode 113 is exposed on the second end face 110d, and the second negative electrode internal electrode 123 is exposed on the eighth end face 120f.

[Common external electrode]
The vibration generator 100 may comprise a positive external electrode and a negative external electrode connected to both the first piezoelectric actuator 110 and the second piezoelectric actuator 120 . FIG. 26 is a schematic diagram showing the positive external electrode 131. As shown in FIG. The positive electrode external electrode 131 is made of a conductive material and formed on the first end surface 110c, the third end surface 110e and the seventh end surface 120e (see FIG. 24). As described above, the first positive internal electrode 112 is exposed on the first end surface 110c, and the second positive internal electrode 122 is exposed on the seventh end surface 120e. and the second positive internal electrode 122 .

27 is a schematic diagram showing the negative external electrode 132. As shown in FIG. The negative external electrode 132 is made of a conductive material and formed on the second end surface 110d, the fourth end surface 110f and the eighth end surface 120f (see FIG. 25). As described above, the first negative internal electrode 113 is exposed on the second end surface 110d, and the second negative internal electrode 123 is exposed on the eighth end surface 120f. and the second negative electrode internal electrode 123 .

The positive electrode external electrode 131 and the negative electrode external electrode 132 are connected to a drive unit (not shown), and drive signals output from the drive unit are applied to the first positive internal electrode 112, the first negative internal electrode 113, the second positive internal electrode 122, and the second internal electrode 122, respectively. They are transmitted to the negative internal electrodes 123 respectively. In this configuration, since the positive external electrode 131 and the negative external electrode 132 are common to the first piezoelectric actuator 110 and the second piezoelectric actuator 120, the same drive signal is supplied to the first piezoelectric actuator 110 and the second piezoelectric actuator 120.

[Independent external electrodes]
The vibration generator 100 can also include two positive external electrodes and two negative external electrodes connected to the first piezoelectric actuator 110 and the second piezoelectric actuator 120, respectively.

FIG. 28 is a schematic diagram showing the first positive external electrode 141 and the second positive external electrode 151. As shown in FIG. The first positive external electrode 141 is made of a conductive material and formed on the first end face 110c (see FIG. 24). Since the first positive internal electrode 112 is exposed on the first end surface 110 c as described above, the first positive external electrode 141 is electrically connected to the first positive internal electrode 112 . The second positive external electrode 151 is made of a conductive material and formed on the third end surface 110e and the seventh end surface 120e (see FIG. 24). Since the second positive internal electrode 122 is exposed on the seventh end surface 120 e as described above, the second positive external electrode 151 is electrically connected to the second positive internal electrode 122 .

FIG. 29 is a schematic diagram showing the first negative external electrode 142 and the second negative external electrode 152. As shown in FIG. The first negative external electrode 142 is made of a conductive material and formed on the second end surface 110d (see FIG. 25). Since the first negative internal electrode 113 is exposed on the second end surface 110 d as described above, the first negative external electrode 142 is electrically connected to the first negative internal electrode 113 . The second negative external electrode 152 is made of a conductive material and formed on the fourth end surface 110f and the eighth end surface 120f (see FIG. 25). Since the second negative electrode internal electrode 123 is exposed on the eighth end face 120f as described above, the second negative external electrode 152 is electrically connected to the second negative internal electrode 123 .

The first positive external electrode 141, the first negative external electrode 142, the second positive external electrode 151, and the second negative external electrode 152 are connected to a driving section (not shown). The first positive external electrode 141 and the first negative external electrode 142 transmit the driving signal output from the driver to the first positive internal electrode 112 and the first negative internal electrode 113 . The second positive external electrode 151 and the second negative external electrode 152 transmit driving signals output from the driver to the second positive internal electrode 122 and the second negative internal electrode 123 .

In this configuration, the first positive external electrode 141 and the first negative external electrode 142 function as external electrodes for the first piezoelectric actuator 110 , and the second positive external electrode 151 and the second negative external electrode 152 function for the second piezoelectric actuator 120 . function as an external electrode of Therefore, different drive signals can be supplied to the first piezoelectric actuator 110 and the second piezoelectric actuator 120 . One of the positive electrode and the negative electrode may be a common external electrode, and the other may be an independent external electrode. A configuration in which the electrode 152 conducts is also possible.

[Regarding the drive signal for the first piezoelectric actuator]
The waveform of the drive signal output from the drive section to the first piezoelectric actuator 110 will be described. In addition, although the signal wave in the low frequency region is assumed to be a sine wave for convenience in the following description, it is not limited to this.

FIG. 30 shows a voltage waveform and a current waveform which are sinusoidal waves in a high frequency region with a frequency of 20 kHz or more and 100 kHz or less. When the voltage waveform shown in FIG. 30 is applied from the drive unit to the first piezoelectric actuator 110 as a drive signal, a current having the current waveform shown in FIG. 30 flows. Vibration in a high frequency range of 20 kHz or more and 100 kHz or less is vibration that causes a floating phenomenon.

FIG. 31 shows a voltage waveform and a current waveform which are sinusoidal waves in a low frequency region with a frequency of 1 Hz or more and 250 Hz or less. When the voltage waveform shown in FIG. 31 is applied as a drive signal from the driving section to the first piezoelectric actuator 110, a current having the current waveform shown in FIG. 31 flows. Vibrations in the low-frequency range of 1 Hz to 250 Hz are vibrations that can be sensitively sensed by Meissner's corpuscles, Pacinian corpuscles, and the like, which are receptors on human skin.

FIG. 32 shows voltage waveforms and current waveforms having waveforms of amplitude-modulated waves obtained by using a sine wave (signal wave) in a low frequency range as a modulated wave and amplitude-modulating a sine wave in a high frequency range by this modulated wave. 33 is an enlarged view of FIG. 32. FIG. When the voltage waveform shown in FIG. 32 is applied as a drive signal from the driving section to the first piezoelectric actuator 110, a current having the current waveform shown in FIG. 32 flows.

34 shows only the voltage waveforms of FIG. 32, and FIG. 35 shows only the voltage waveforms of FIG. In FIGS. 34 and 35, a wave with a small wavelength indicated by W1 is a sine wave in the high frequency region, and a 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 range will be referred to as the high frequency W1, and the sine wave in the low frequency range will be referred to as the low frequency W2.

In the waveforms shown in FIGS. 34 and 35, the low frequency W2 is formed by changes in the amplitude of the high frequency W1, that is, the waveforms shown in FIGS. 34 and 35 have the high frequency W1 as the carrier wave and the low frequency W2 as the modulating wave. It is an amplitude modulated wave. 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.

The voltage gain of the high frequency W1 is preferably -10 dB or more and 0 dB or less, and the voltage gain of the low frequency W2 is preferably -6 dB or more and 0 dB or less. FIG. 36 is a schematic diagram showing the relationship between the waveform of the amplitude modulated wave and the voltage gain. As shown in the figure, if the "peak" amplitude of the amplitude-modulated wave is amplitude a and the "trough" amplitude is amplitude b, the degree of modulation m is expressed by the following (Equation 1). As shown in the following (Equation 1), the smaller the amplitude b with respect to the amplitude a, the larger the degree of modulation m.

m=(ab)/(a+b) (Formula 1)

In FIG. 36 as well, when the voltage gain of the low frequency W2 is increased, the "trough" of the low frequency W2 becomes deeper as indicated by the white arrow in FIG. ” is the smallest. Also, when the voltage gain of the low frequency W2 is lowered to approach -6 dB, the "trough" of the low frequency W2 becomes shallower and the amplitude becomes larger. Further, when the voltage gain of the low frequency W2 is lowered to approach -10 dB, the amplitude b of the "trough" of the low frequency W2 becomes equal to the amplitude of the "peak" and no "trough" is formed.

In this embodiment, the voltage gains of high frequency W1 and low frequency W2 are adjusted to a range in which a "trough" is formed. Specifically, the voltage gain of the high frequency W1 is preferably -10 dB or more and 0 dB or less, and the voltage gain of the low frequency W2 is preferably -6 dB or more and 0 dB or less. Moreover, 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.

[Regarding the drive signal for the second piezoelectric actuator]
The waveform of the drive signal output from the drive section to the second piezoelectric actuator 120 will be described. In addition, although the signal wave in the low frequency region is assumed to be a sine wave for convenience in the following description, it is not limited to this.

When the external electrodes of the first piezoelectric actuator 110 and the second piezoelectric actuator 120 are common (see FIGS. 26 and 27), the driving section supplies the same drive signal to the first piezoelectric actuator 110 and the second piezoelectric actuator 120. . That is, the second piezoelectric actuator 120 is also supplied with an amplitude modulated wave (see FIGS. 34 and 35) having the high frequency W1 as the carrier wave and the low frequency W2 as the modulated wave.

When the external electrodes of the first piezoelectric actuator 110 and the second piezoelectric actuator 120 are independent (see FIGS. 28 and 29), the second piezoelectric actuator 120 can be supplied with a drive signal different from that of the first piezoelectric actuator 110 . Specifically, the drive unit can supply the second piezoelectric actuator 120 with an amplitude modulated wave in which the carrier wave is the first low frequency and the modulated wave is the second low frequency. It is preferable that the first low frequency be 110 Hz or more and 250 Hz or less, and the second low frequency be 1 Hz or more and 50 Hz or less.

[About the mounting structure of the vibration generator]
A mounting structure of the vibration generator 100 will be described. The vibration generator 100 can be bonded to the vibration member. 37 is a perspective view of the vibration generator 100 joined to the vibration member 180, and FIG. 38 is a plan view of the vibration generator 100 joined to the vibration member 180. FIG. The vibration member 180 is a member to which the vibration of the vibration generator 100 is transmitted, and is not particularly limited to a display panel, a track pad, a housing of an electronic device, or the like. As shown in FIG. 38, the vibration member 180 is bonded to the fourth main surface 120b of the second piezoelectric actuator 120. As shown in FIG. Two vibration generators 100 may be joined to both ends of the vibration member 180 as shown in FIG. 37 , or one or more vibration generators 100 may be joined to the vibration member 180 . Alternatively, the vibration generator 100 may be arranged at the center of the mouse or the like so that the user can directly touch the fourth main surface 120b.

[Effect of vibration generator]
The vibration generator 100 is configured by stacking the first piezoelectric actuator 110 that vibrates in the d31 mode and the second piezoelectric actuator 120 that vibrates in the d33 mode as described above. Therefore, the d31-mode first piezoelectric actuator 110 can express vibration in the force feedback region (low-frequency region), and the d33-mode second piezoelectric actuator 120 can express high-frequency levitation vibration. Furthermore, by generating high-frequency vibration in the first piezoelectric actuator 110, the protrusion shape of the second piezoelectric actuator 120 contributes, and fine levitation vibration can be expressed.

Furthermore, in the vibration generator 100, the drive section can output a drive signal having a voltage waveform of an amplitude-modulated wave as shown in FIG. This amplitude-modulated wave is obtained by amplitude-modulating the high frequency W1 that causes the floating phenomenon by the low frequency W2 that can be sensitively sensed by Meissner's corpuscles and Pacinian corpuscles, which are receptors on the human skin. , when the user touches the fourth main surface 120b or the vibrating member 180 with the finger, a delicate tactile sensation can be realistically presented to the user's finger. Further, by moving the finger while keeping it in contact, the tactile sensation can be increased.

Furthermore, since the high frequency W1 is amplitude-modulated, the current average of the entire waveform is smaller than when it is not amplitude-modulated, and power consumption and heat generation can be reduced. In particular, if the voltage gain of the high frequency W1 is -10 dB or more and 0 dB or less, and the voltage gain of the low frequency W2 is -6 dB or more and 0 dB or less, a "trough" (white arrow in FIG. 34) is formed, so power consumption and heat generation can be reduced. can do. Furthermore, if the voltage gain of the high frequency W1 is −10 dB and the voltage gain of the low frequency W2 is 0 dB, the “valley” becomes the deepest and power consumption and heat generation can be minimized. Also, it is possible to suppress the generation of abnormal noise due to the levitation phenomenon by the amplitude modulated wave.

[Method for manufacturing vibration generator]
The vibration generator 100 can be manufactured as follows. First, the first piezoelectric layer 111, the first positive internal electrode 112 and the first negative internal electrode 113 (see FIG. 5) are stacked, and the second piezoelectric layer 121, the second positive internal electrode 122 and the second positive internal electrode 122 are stacked thereon. A negative electrode internal electrode 123 (see FIG. 13) is laminated. This laminate is heated to sinter the first piezoelectric layer 111 and the second piezoelectric layer 121 . Subsequently, the second piezoelectric layer 121, the second positive internal electrode 122, and the second negative internal electrode 123 are cut to form a plurality of second piezoelectric actuators 120 (see FIG. 2). As a result, the vibration generator 100 in which the plurality of second piezoelectric actuators 120 are stacked on one first piezoelectric actuator 110 is formed. Thus, the vibration generator 100 can be manufactured by a single sintering process. Note that the vibration generator 100 can also be manufactured by other manufacturing methods.

(Second embodiment)
A vibration generator according to a second embodiment of the present invention will be described.

[Configuration of vibration generator]
FIG. 39 is a perspective view of the vibration generator 200 according to this embodiment, and FIG. 40 is an exploded perspective view of the vibration generator 200. As shown in FIG.

As shown in FIGS. 39 and 40, the vibration generator 200 includes one first piezoelectric actuator 110 and a plurality of second piezoelectric actuators 220, and the plurality of second piezoelectric actuators 220 are stacked on one first piezoelectric actuator 110. configured. Since the first piezoelectric actuator 110 has a configuration similar to that of the first embodiment, the same reference numerals as those of the first embodiment are given, and description thereof is omitted.

41 is a perspective view of the second piezoelectric actuator 220, and FIG. 42 is a plan view of the second piezoelectric actuator 220. FIG. As shown in FIGS. 41 and 42, the second piezoelectric actuator 220 has a flat plate shape whose main surface is parallel to the XY plane and whose X-direction length and Y-direction length are the same. Hereinafter, of the main surfaces of the second piezoelectric actuator 220, the main surface on the first piezoelectric actuator 110 side will be referred to as a third main surface 220a, and the main surface opposite to the third main surface 220a will be referred to as a fourth main surface 220b. Further, one end surface perpendicular to the first direction (X direction) and parallel to the second direction (Z direction) is defined as a fifth end surface 220c, and the fifth end surface 220c is perpendicular to the first direction, parallel to the second direction and parallel to the second direction. is the sixth end face 220d. Further, one end surface parallel to the first direction and the second direction is defined as a seventh end surface 220e, and an end surface parallel to the first direction and the second direction and opposite to the seventh end surface 220e is defined as an eighth end surface 220f.

43 is a cross-sectional view of the second piezoelectric actuator 120, taken along line CC of FIG. 42. FIG. As shown in the figure, the second piezoelectric actuator 220 includes a second piezoelectric layer 221 , a second positive internal electrode 222 and a second negative internal electrode 223 . The second piezoelectric layer 221 is made of a piezoelectric material such as PZT (lead zirconate titanate).

The second positive internal electrode 222 is made of a conductive material, is provided in the second piezoelectric layer 221 , and faces the second negative internal electrode 223 with the second piezoelectric layer 221 interposed therebetween. The second positive internal electrode 222 has a flat plate shape, and when the main surface of the second positive internal electrode 222 is the electrode surface, the electrode surface is parallel to the third main surface 220a and the fourth main surface 220b (XY plane), That is, it is parallel to the first direction (X direction). As for the 2nd positive electrode internal electrode 222, five sheets may be provided as shown in FIG. 43, and four sheets or less or six sheets or more may be provided.

FIG. 44 is a schematic diagram showing the arrangement of the second positive internal electrode 222 in the second piezoelectric actuator 220. As shown in FIG. As shown in the figure, one side of the second positive electrode internal electrode 222 coincides with the seventh end surface 220e, and the other peripheral edge is arranged apart from the fifth end surface 220c, the sixth end surface 220d and the eighth end surface 220f. .

The second negative internal electrode 223 is made of a conductive material, is provided in the second piezoelectric layer 221 , and faces the second positive internal electrode 222 with the second piezoelectric layer 221 interposed therebetween. The second negative internal electrode 223 has a flat plate shape, and when the main surface of the second negative internal electrode 223 is the electrode surface, the electrode surface is parallel to the third main surface 220a and the fourth main surface 220b (XY plane), That is, it is parallel to the first direction (X direction). Five second negative electrode internal electrodes 223 may be provided as shown in FIG. 43, or four or less or six or more may be provided.

FIG. 45 is a schematic diagram showing the arrangement of the second negative internal electrode 223 in the second piezoelectric actuator 220. As shown in FIG. As shown in the figure, one side of the second negative electrode internal electrode 223 coincides with the eighth end face 220f, and the other peripheral edge is spaced apart from the fifth end face 220c, the sixth end face 220d and the seventh end face 220f. .

FIG. 46 is a perspective view showing the seventh end surface 220e. As shown in the figure, the end of the second positive internal electrode 222 is exposed on the seventh end surface 220e, and the second negative internal electrode 223 is not exposed. Also, FIG. 47 is a perspective view showing the eighth end surface 220f. As shown in the figure, the end of the second negative internal electrode 223 is exposed on the eighth end surface 220f, and the second positive internal electrode 222 is not exposed.

The second piezoelectric actuator 220 has such a configuration. FIG. 48 is a schematic diagram showing vibration of the second piezoelectric actuator 220. FIG. When a voltage is applied between the second positive internal electrode 222 and the second negative internal electrode 223 , the second piezoelectric actuator 220 moves the second positive internal electrode 222 and the second negative internal electrode 222 due to the reverse piezoelectric effect in the second piezoelectric layer 221 . It expands and contracts along the second direction (Z direction) perpendicular to the electrode surface of 223 (the arrow in the figure) to generate vibration. Such expansion and contraction is called the d33 mode, and the second piezoelectric actuator 220 is a piezoelectric actuator that vibrates in the d33 mode.

[Regarding the positional relationship between the first piezoelectric actuator and the second piezoelectric actuator]
The positional relationship between the first piezoelectric actuator 110 and the second piezoelectric actuator 220 will be described below. 49 to 53 are plan views of the vibration generator 200 viewed from various directions. As shown in FIGS. 49 to 51, the second piezoelectric actuators 220 are arranged in two rows on the first piezoelectric actuator 110 along the first direction (X direction) with the eighth end face 220f facing outward. there is 52 and 53, the seventh end surface 220e of the second piezoelectric actuator 220 faces the seventh end surface 220e of the adjacent second piezoelectric actuator 220, and the eighth end surface 220f faces the first piezoelectric actuator 110. is continuous with the third end surface 110e and the fourth end surface 110f of the .

FIG. 54 is a perspective view of the vibration generator 200 viewed from the first end face 110c and the third end face 110e. As shown in the figure, the first positive internal electrode 112 is exposed on the first end surface 110c, and the second negative internal electrode 223 is exposed on the eighth end surface 220f. FIG. 55 is a perspective view of the vibration generator 200 viewed from the second end surface 110d and the fourth end surface 110f. As shown in the figure, the first negative electrode internal electrode 113 is exposed on the second end face 110d, and the second negative electrode internal electrode 223 is exposed on the eighth end face 220f.

Furthermore, as shown in FIGS. 54 and 55, between the rows of the second piezoelectric actuators 220, the seventh end faces 220e face each other, and the second positive electrode internal electrodes 222 are exposed on the seventh end faces 220e.

[Common external electrode]
The vibration generator 200 may comprise a positive external electrode and a negative external electrode connected to both the first piezoelectric actuator 110 and the second piezoelectric actuator 220 . FIG. 56 is a schematic diagram showing the positive external electrode 231. As shown in FIG. The positive external electrode 231 is made of a conductive material and formed on the first end surface 110c and the seventh end surface 220e (see FIG. 54). As described above, the first positive internal electrode 112 is exposed on the first end surface 110c, and the second positive internal electrode 222 is exposed on the seventh end surface 220e. and the second positive internal electrode 222 .

Also, FIG. 57 is a schematic diagram showing the negative electrode external electrode 232 . The negative electrode external electrode 232 is made of a conductive material and formed on the second end surface 110d and the eighth end surface 220f (see FIG. 55). As described above, the first negative internal electrode 113 is exposed on the second end face 110d, and the second negative internal electrode 223 is exposed on the eighth end face 220f. and the second negative electrode internal electrode 223 .

The positive electrode external electrode 231 and the negative electrode external electrode 232 are connected to a drive unit (not shown), and drive signals output from the drive unit are applied to the first positive internal electrode 112, the first negative internal electrode 113, the second positive internal electrode 222, and the second internal electrode 222, respectively. They are transmitted to the negative internal electrodes 223 respectively. In this configuration, since the positive external electrode 231 and the negative external electrode 232 are common to the first piezoelectric actuator 110 and the second piezoelectric actuator 220, the same drive signal is supplied to the first piezoelectric actuator 110 and the second piezoelectric actuator 220.

[Independent external electrodes]
The vibration generator 200 can also include two positive external electrodes and two negative external electrodes connected to the first piezoelectric actuator 110 and the second piezoelectric actuator 220, respectively.

58 is a schematic diagram showing the first positive external electrode 241 and the second positive external electrode 251. FIG. The first positive external electrode 241 is made of a conductive material and formed on the first end face 110c (see FIG. 54). Since the first positive internal electrode 112 is exposed on the first end surface 110 c as described above, the first positive external electrode 241 is electrically connected to the first positive internal electrode 112 . The second positive external electrode 251 is made of a conductive material and formed on the seventh end surface 220e (see FIG. 54). Since the second positive internal electrode 222 is exposed on the seventh end surface 220 e as described above, the second positive external electrode 251 is electrically connected to the second positive internal electrode 222 .

FIG. 59 is a schematic diagram showing the first negative external electrode 242 and the second negative external electrode 252. As shown in FIG. The first negative external electrode 242 is made of a conductive material and formed on the second end face 110d (see FIG. 55). Since the first negative internal electrode 113 is exposed on the second end surface 110 d as described above, the first negative external electrode 242 is electrically connected to the first negative internal electrode 113 . The second negative external electrode 252 is made of a conductive material and formed on the third end surface 110e, the fourth end surface 110f and the eighth end surface 220f (see FIG. 55). Since the second negative electrode internal electrode 223 is exposed on the eighth end face 220f as described above, the second negative external electrode 252 is electrically connected to the second negative internal electrode 223 .

The first positive external electrode 241, the first negative external electrode 242, the second positive external electrode 251, and the second negative external electrode 252 are connected to a driving section (not shown). The first positive external electrode 241 and the first negative external electrode 242 transmit the driving signal output from the driver to the first positive internal electrode 112 and the first negative internal electrode 113 . The second positive external electrode 251 and the second negative external electrode 252 transmit the driving signal output from the driver to the second positive internal electrode 222 and the second negative internal electrode 223 .

In this configuration, the first positive external electrode 241 and the first negative external electrode 242 function as external electrodes for the first piezoelectric actuator 110 , and the second positive external electrode 251 and the second negative external electrode 252 function for the second piezoelectric actuator 220 . function as an external electrode of Therefore, different drive signals can be supplied to the first piezoelectric actuator 110 and the second piezoelectric actuator 220 . One of the positive electrode and the negative electrode may be a common external electrode, and the other may be an independent external electrode. A configuration in which the electrode 252 conducts is also possible.

[Regarding drive signals for the first piezoelectric actuator and the second piezoelectric actuator]
The drive signals for the first piezoelectric actuator 110 and the second piezoelectric actuator 120 can be the same as in the first embodiment. That is, the drive signal for the first piezoelectric actuator 110 can be an amplitude modulated wave (see FIGS. 34 and 35) with the high frequency W1 as the carrier wave and the low frequency W2 as the modulation wave. It is preferable that the high frequency W1 is 20 kHz or more and 100 kHz or less, and the low frequency W2 is 1 Hz or more and 250 Hz or less. The drive signal for the second piezoelectric actuator 220 can be the same as that for the first piezoelectric actuator 110, or can be an amplitude modulated wave in which the carrier wave is the first low frequency and the modulated wave is the second low frequency. It is preferable that the first low frequency be 110 Hz or more and 250 Hz or less, and the second low frequency be 1 Hz or more and 50 Hz or less.

[About the mounting structure of the vibration generator]
A mounting structure of the vibration generator 200 will be described. The vibration generator 200 can be bonded to the vibration member. 60 is a perspective view of the vibration generator 200 joined to the vibration member 280, and FIG. 61 is a plan view of the vibration generator 200 joined to the vibration member 280. FIG. Vibration member 280 is a member to which vibration of vibration generator 200 is transmitted, and is not particularly limited to a display panel, a track pad, a housing of an electronic device, or the like. As shown in FIG. 61, the vibration member 280 is bonded to the fourth main surface 220b of the second piezoelectric actuator 220. As shown in FIG. Two vibration generators 200 may be joined to opposite ends of the vibration member 280 as shown in FIG. 60, or one or more than three vibration generators 200 may be joined to the vibration member 280. Alternatively, the vibration generator 200 may be arranged at the center of the mouse or the like so that the user can directly touch the fourth main surface 220b.

[Effect of vibration generator]
The effects of the vibration generator 200 are the same as those of the vibration generator 100 . That is, the d31 mode first piezoelectric actuator 110 can express vibration in the force feedback region (low frequency region), and the d33 mode second piezoelectric actuator 220 can express high frequency levitation vibration. Furthermore, by generating high-frequency vibration in the first piezoelectric actuator 110, the protrusion shape of the second piezoelectric actuator 220 contributes, and fine levitation vibration can be expressed.

Further, in the vibration generating device 200, the drive section outputs a drive signal having a voltage waveform of an amplitude-modulated wave as shown in FIG. 280, a delicate tactile sensation can be realistically presented to the user's finger. Further, by moving the finger while keeping it in contact, the tactile sensation can be increased. Furthermore, since the high frequency W1 is amplitude-modulated, the current average of the entire waveform is smaller than when it is not amplitude-modulated, and power consumption and heat generation can be reduced. Also, it is possible to suppress the generation of abnormal noise due to the levitation phenomenon by the amplitude modulated wave.

[Method for manufacturing vibration generator]
The vibration generator 200 can be manufactured by the same method as the vibration generator 100 according to the first embodiment. That is, the first piezoelectric layer 111, the first positive internal electrode 112 and the first negative internal electrode 113 (see FIG. 5) are laminated, and the second piezoelectric layer 221, the second positive internal electrode 222 and the second positive internal electrode 222 are laminated thereon. A negative electrode internal electrode 223 (see FIG. 43) is laminated. This laminate is heated to sinter the first piezoelectric layer 111 and the second piezoelectric layer 221 . Subsequently, the second piezoelectric layer 221, the second positive internal electrode 222 and the second negative internal electrode 223 are cut to form a plurality of second piezoelectric actuators 220 (see FIG. 40). As a result, the vibration generator 200 in which the plurality of second piezoelectric actuators 220 are stacked on one first piezoelectric actuator 110 is formed. Thus, the vibration generator 200 can be manufactured by a single sintering process. Note that the vibration generator 200 can also be manufactured by other manufacturing methods.

DESCRIPTION OF SYMBOLS 100... Vibration generator 110... 1st piezoelectric actuator 111... 1st piezoelectric layer 112... 1st positive internal electrode 113... 1st negative internal electrode 120... 2nd piezoelectric actuator 121... 2nd piezoelectric layer 122... 2nd positive electrode Internal electrode 123 Second negative internal electrode 131 Positive external electrode 132 Negative external electrode 141 First positive external electrode 142 First negative external electrode 151 Second positive external electrode 152 Second negative external electrode 180 Vibration Member 200 Vibration generator 220 Second piezoelectric actuator 221 Second piezoelectric layer 222 Second positive internal electrode 223 Second negative internal electrode 231 Positive external electrode 232 Negative external electrode 241 First positive external electrode 242 First negative external electrode 251 Second positive external electrode 252 Second negative external electrode 280 Vibration member

Claims (11)

a first piezoelectric layer made of a piezoelectric material; a first positive internal electrode provided in the first piezoelectric layer; a positive internal electrode and a first negative internal electrode facing each other, wherein when a voltage is applied between the first positive internal electrode and the first negative internal electrode, the first positive internal electrode and the first negative internal electrode a first piezoelectric actuator that expands and contracts along a first direction parallel to the electrode surface of the electrode;
a second piezoelectric layer laminated on the first piezoelectric actuator and made of a piezoelectric material; a second positive electrode internal electrode provided in the second piezoelectric layer; A second negative internal electrode facing the second positive internal electrode via a second piezoelectric layer is provided, and when a voltage is applied between the second positive internal electrode and the second negative internal electrode, the A vibration generator comprising: a second piezoelectric actuator that expands and contracts along a second direction perpendicular to the electrode surfaces of the second positive electrode internal electrode and the second negative electrode internal electrode and perpendicular to the first direction. The vibration generator according to claim 1,
The first piezoelectric actuator has a first end face perpendicular to the first direction and parallel to the second direction, and a first end face perpendicular to the first direction and parallel to the second direction. a second end face that is an end face on the opposite side, a third end face that is an end face parallel to the first direction and the second direction, and a third end face parallel to the first direction and the second direction and the third end face and a fourth end face that is the opposite end face, the end of the first positive electrode internal electrode is exposed on the first end face, the end of the first negative electrode internal electrode is exposed on the second end face,
The second piezoelectric actuator has a fifth end face perpendicular to the first direction and parallel to the second direction, and a fifth end face perpendicular to the first direction and parallel to the second direction. A sixth end surface that is an end surface on the opposite side, a seventh end surface that is an end surface parallel to the first direction and the second direction, and a seventh end surface parallel to the first direction and the second direction and the seventh end surface and an eighth end face which is an end face on the opposite side, the end of the second positive electrode internal electrode is exposed on the seventh end face, and the end of the second negative electrode internal electrode is exposed on the eighth end face. Generator. The vibration generator according to claim 2,
comprising a plurality of the second piezoelectric actuators arranged in a row along the first direction;
The seventh end surface is a surface continuous with the third end surface,
The vibration generator, wherein the eighth end surface is a surface continuous with the fourth end surface. The vibration generator according to claim 3,
a positive electrode external electrode provided on the first end face, the third end face, and the seventh end face and electrically connected to the first positive electrode internal electrode and the second positive electrode internal electrode;
The vibration generating device further comprising: a negative electrode external electrode provided on the second end surface, the fourth end surface, and the eighth end surface and electrically connected to the first internal negative electrode and the second internal negative electrode. The vibration generator according to claim 3,
a first positive electrode external electrode provided on the first end face and electrically connected to the first positive electrode internal electrode;
a first negative electrode external electrode provided on the second end surface and electrically connected to the first negative electrode internal electrode;
a second positive electrode external electrode provided on the seventh end face and electrically connected to the second positive electrode internal electrode;
The vibration generator further comprising: a second negative electrode external electrode provided on the eighth end surface and electrically connected to the second negative electrode internal electrode. The vibration generator according to claim 2,
comprising a plurality of the second piezoelectric actuators arranged in two rows along the first direction;
the seventh end face faces the seventh end face of the adjacent second piezoelectric actuator;
The vibration generator, wherein the eighth end surface is a surface continuous with the third end surface and the fourth end surface. The vibration generator according to claim 6,
a positive electrode external electrode provided on the first end face and the seventh end face and electrically connected to the first positive internal electrode and the second positive internal electrode;
a negative electrode external electrode provided on the second end surface, the third end surface, the fourth end surface, and the eighth end surface and electrically connected to the first internal negative electrode and the second internal negative electrode; vibration generator. The vibration generator according to claim 6,
a first positive electrode external electrode provided on the first end face and electrically connected to the first positive electrode internal electrode;
a first negative electrode external electrode provided on the second end surface and electrically connected to the first negative electrode internal electrode;
a second positive electrode external electrode provided on the seventh end face and electrically connected to the second positive electrode internal electrode;
The vibration generator further comprising: a second negative electrode external electrode provided on the eighth end surface and electrically connected to the second negative electrode internal electrode. The vibration generator according to claim 5 or 7,
A drive signal having a waveform obtained by amplitude-modulating a signal wave in a low-frequency region with a frequency of 1 Hz or more and 250 Hz or less as a modulated wave and a sine wave in a high-frequency region with a frequency of 20 kHz or more and 100 kHz or less by the modulated wave. A vibration generator, further comprising a driving unit for supplying power to the positive external electrode and the negative external electrode. The vibration generator according to claim 6 or 8,
A drive signal having a waveform obtained by amplitude-modulating a signal wave in a low-frequency region with a frequency of 1 Hz or more and 250 Hz or less as a modulated wave and a sine wave in a high-frequency region with a frequency of 20 kHz or more and 100 kHz or less by the modulated wave. A vibration generating device, further comprising a driving unit that supplies power to the first positive external electrode and the first negative external electrode. a first piezoelectric layer made of a piezoelectric material; a first positive internal electrode provided in the first piezoelectric layer; a positive internal electrode and a first negative internal electrode facing each other, wherein when a voltage is applied between the first positive internal electrode and the first negative internal electrode, the first positive internal electrode and the first negative internal electrode a first piezoelectric actuator that expands and contracts along a first direction parallel to the electrode surface of the electrode;
a second piezoelectric layer laminated on the first piezoelectric actuator and made of a piezoelectric material; a second positive electrode internal electrode provided in the second piezoelectric layer; A second negative internal electrode facing the second positive internal electrode via a second piezoelectric layer is provided, and when a voltage is applied between the second positive internal electrode and the second negative internal electrode, the An electronic device, comprising: a second piezoelectric actuator that expands and contracts along a second direction perpendicular to electrode surfaces of a second positive electrode internal electrode and the second negative electrode internal electrode and perpendicular to the first direction.

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