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DESCRIPTION JP2018113638

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DESCRIPTION JP2018113638
Abstract: PROBLEM TO BE SOLVED: To provide an acoustic generator capable of generating both
acoustic and ultrasonic waves in an audible band. A sound generator (10) includes a vibrating
body (20). The size in the longitudinal direction (X direction) of the vibrating body 20 is larger
than the size in the width direction (Y direction). The vibrator 20 includes a piezoelectric element
30. The piezoelectric element 30 is provided with a plurality of main terminals 310 and a
plurality of sub terminals 320. The main terminal 310 is for inputting a main drive signal to the
piezoelectric element 30. When the main drive signal is input to the piezoelectric element 30, the
vibrating body 20 vibrates to wave in a predetermined direction (Z direction). The auxiliary
terminal 320 is for inputting an auxiliary drive signal to the piezoelectric element 30. When the
sub drive signal is input to the piezoelectric element 30, the vibrator 20 vibrates in the
longitudinal direction so as to output an ultrasonic wave from the end in the longitudinal
direction. [Selected figure] Figure 2
Sound generator
[0001]
The present invention relates to a sound generating device that generates sound by vibrating a
piezoelectric plate.
[0002]
Patent Document 1 discloses an acoustic generator of this type.
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1
The sound generator disclosed in Patent Document 1, for example, is mounted inside a mobile
phone and vibrates the display surface of the mobile phone to generate sound waves in the
audible band.
[0003]
Patent Document 2 discloses an ultrasonic wave generator that generates ultrasonic waves by
vibrating a piezoelectric plate. The ultrasound generated by the ultrasound generator is used to
measure the distance.
[0004]
Patent No. 5676043 Patent No. 5556893
[0005]
When calling using a mobile phone, the caller's face may touch the display surface of the mobile
phone.
In order to prevent a touch on a button or the like displayed on the display surface, it is
necessary to erase the screen during a call. In this case, the screen can be erased based on the
measured distance by measuring the distance between the face of the caller and the panel using
ultrasonic waves. However, considering that the internal space of the mobile phone is small, it is
not preferable to incorporate a device for generating an ultrasonic wave in addition to the device
for generating an acoustic wave in the audible band inside the mobile phone. Not limited to
mobile phones, it is not preferable to incorporate an apparatus that generates sound waves in the
audible band and an apparatus that generates ultrasonic waves in an apparatus having a limited
internal space.
[0006]
Then, an object of this invention is to provide the sound generator which can generate | occur |
produce both the sound wave of an audible zone, and an ultrasonic wave.
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2
[0007]
The present invention is a sound generator including a vibrator as a first sound generator,
wherein a size in a longitudinal direction of the vibrator is larger than a size in a width direction
orthogonal to the longitudinal direction. The piezoelectric element includes a plurality of main
terminals and a plurality of sub terminals, and the main terminal is for inputting a main drive
signal to the piezoelectric element. When the main drive signal is input to the piezoelectric
element, the vibrator vibrates so as to wave in a predetermined direction orthogonal to both the
longitudinal direction and the width direction, and the sub terminal transmits to the piezoelectric
element. It is for inputting an auxiliary drive signal, and when the auxiliary drive signal is input to
the piezoelectric element, the vibrator stretches and vibrates in the longitudinal direction, and
outputs an ultrasonic wave from the end in the longitudinal direction. To provide a sound
generating device.
[0008]
Further, the present invention is a first sound generator as the second sound generator, which is
a sound generator attachable to a housing, comprising a support, wherein the support is a
support And the to-be-fixed portion, wherein the support portion extends longer than the to-befixed portion in the longitudinal direction on a plane defined by the longitudinal direction and the
width direction, The portion extends from the support portion in the width direction, the
piezoelectric element is supported by the support portion, and constitutes the vibrating body
together with the support portion. In the attached state attached to the housing, the fixed portion
is fixed to the housing, and the supporting portion is apart from the housing.
[0009]
The present invention is the first or second sound generator as the third sound generator,
wherein the piezoelectric element has a flat plate shape, and the size of the piezoelectric element
in the longitudinal direction is The present invention provides an acoustic generator larger than
the size in the width direction.
[0010]
Further, the present invention provides a sound generator according to any one of the first to the
third sound generators as the fourth sound generator, wherein the piezoelectric element has a
bimorph structure.
[0011]
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The vibrator of the sound generator according to the invention vibrates in a wave-like manner by
the main drive signal.
By this vibration, sound waves in the audible band can be output.
In addition, the vibrator of the sound generator according to the present invention vibrates in an
elastic manner by the sub drive signal to output an ultrasonic wave.
That is, the sound generator according to the present invention can generate both sound waves
and ultrasonic waves in the audible band.
[0012]
It is a perspective view showing electronic equipment incorporating a sound generator according
to an embodiment of the present invention.
It is a partially cutaway perspective view which shows the electronic device of FIG. 1 along a II-II
line.
It is a side view which shows typically the structure of the piezoelectric element of the sound
generation apparatus of FIG. It is another side view which shows the structure of the
piezoelectric element of FIG. It is a front view which shows the structure of the piezoelectric
element of FIG. 2 in further detail. It is a figure which shows the frequency characteristic of the
sound pressure of the sound wave which generate | occur | produces in the sound generator of
FIG. It is a partially cutaway perspective view which shows the electronic device incorporating
the sound generation apparatus by a 1st modification. It is a perspective view which shows the
sound generator of FIG. Only the piezoelectric element and the support in the sound generator
are drawn. It is a partially cutaway perspective view which shows the electronic device which
incorporated the sound generation apparatus by the 2nd modification. It is a partially cutaway
perspective view which shows the electronic device incorporating the sound generation
apparatus by the 3rd modification. It is a perspective view which shows the sound generator by a
4th modification. Only the piezoelectric element and the support in the sound generator are
drawn. It is sectional drawing which shows the sound generator of FIG. 14 along a XII-XII line.
The sound generating device is fixed to a housing of the electronic device.
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[0013]
Referring to FIGS. 1 and 2, an acoustic generator 10 according to an embodiment of the present
invention is a device for generating an acoustic (sound wave), and is incorporated in an electronic
device 80 and used. In the present embodiment, the electronic device 80 is a mobile phone, and
the sound generation device 10 is used to reproduce the voice of the other party. However, the
present invention is not limited to this. For example, the electronic device 80 may be a tablet or a
PC. Further, the sound generation device 10 may be used for applications other than voice
reproduction at the time of a call.
[0014]
As shown in FIGS. 1 and 2, the electronic device 80 includes a housing 82 and a main surface
member 88 separate from the housing 82. The main surface member 88 is made of a rectangular
glass plate, and is a portion that displays the screen of the electronic device 80. The main surface
member 88 extends on a horizontal plane (XY plane) defined by the longitudinal direction (X
direction) and the width direction (Y direction). The housing 82 is made of a material such as
resin or metal and has a generally box shape. Specifically, the housing 82 has a side (side plate)
822 and a bottom (bottom plate) 824. The bottom 824 has a rectangular shape and extends on a
horizontal plane. The bottom 824 is located on the opposite side of the main surface member 88
in a predetermined direction (Z direction) orthogonal to both the longitudinal direction and the
width direction. The side portions 822 are provided on four sides of the bottom 824 in the
horizontal plane, and extend in a predetermined direction.
[0015]
The main surface member 88 is fixed to the upper edge (the edge on the + Z side) of the side
portion 822 of the housing 82, and is thereby supported by the housing 82. When a part of the
housing 82 vibrates, the vibration is transmitted to the main surface member 88 via the bottom
824 and the side portion 822, whereby the main surface member 88 vibrates. That is, the main
surface member 88 functions as a diaphragm.
[0016]
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Referring to FIG. 2, the sound generator 10 includes a piezoelectric element 30 mainly made of a
piezoelectric body, a connecting member 40, and a support 50 made of an elastically deformable
material. The piezoelectric element 30 is deformed due to the reverse piezoelectric effect when a
voltage is applied, and thereby vibrates. The sound generator 10 generates a sound wave using
the vibration of the piezoelectric element 30.
[0017]
As shown in FIG. 2, the piezoelectric element 30 is supported by the support 50 in a state of
being connected to the connection member 40. The support 50 is attached to a housing 82 of the
electronic device 80. That is, the sound generator 10 can be attached to the housing 82 via the
support 50.
[0018]
Specifically, the support 50 includes a support portion 52 and a fixed portion 54. The support
portion 52 has a flat plate shape, and extends on a horizontal plane (XY plane) defined by the
longitudinal direction (X direction) and the width direction (Y direction). The fixed portion 54 has
a flat plate shape, and extends in the width direction from the end of the support portion 52 in
the longitudinal direction. That is, the fixed portion 54 also extends in the horizontal plane. The
support portion 52 extends longer than the fixed portion 54 in the longitudinal direction. A
plurality of screw holes 56 are formed in the fixed portion 54. Each of the screw holes 56
penetrates the fixed portion 54 in a predetermined direction (Z direction) orthogonal to both the
longitudinal direction and the width direction.
[0019]
The piezoelectric element 30 has a flat plate shape, and extends on a horizontal plane (XY plane).
The size of the piezoelectric element 30 in the horizontal plane is smaller than the size of the
support 52 of the support 50 in the horizontal plane. The piezoelectric element 30 is mounted on
the support portion 52 in a predetermined direction (Z direction). The piezoelectric element 30 is
fixed to and supported by the support portion 52, and the support portion 52 vibrates with the
vibration of the piezoelectric element 30. That is, the piezoelectric element 30 constitutes the
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vibrating body 20 together with the support portion 52.
[0020]
The fixed portion 54 of the support 50 is fixed to the fixing portion 84 of the electronic device
80 by a screw (not shown) passed through the screw hole 56. Fixing portion 84 in the present
embodiment is provided at bottom portion 824 of housing 82 of electronic device 80. That is, in
the attached state in which the sound generation device 10 is attached to the housing 82, the
fixed portion 54 is fixed to the housing 82. Further, in the attached state, the support portion 52
is separated from both the housing 82 and the main surface member 88.
[0021]
Referring to FIG. 3, the piezoelectric element 30 includes a first piezoelectric body 340 made of a
piezoelectric body, a first electrode 344 made of a conductor, a second piezoelectric body 350
made of a piezoelectric body, and a second electrode made of a conductor It has 354 and the 3rd
electrode 364 which consists of electric conductors. The first piezoelectric body 340 and the
second piezoelectric body 350 are stacked with the third electrode 364 in between in the
predetermined direction (Z direction). The first electrode 344 is provided on the surface of the
first piezoelectric body 340 in the predetermined direction, and the second electrode 354 is
provided on the surface of the second piezoelectric body 350 in the predetermined direction.
[0022]
The first piezoelectric body 340 and the second piezoelectric body 350 are polarized in opposite
directions to each other in a predetermined direction (Z direction). Specifically, the first
piezoelectric body 340 is polarized by applying a voltage to the first electrode 344 while
grounding the third electrode 364. The second piezoelectric body 350 is polarized by applying a
voltage to the second electrode 354 while grounding the third electrode 364. The polarization
direction of the first piezoelectric body 340 is PD1, and the polarization direction of the second
piezoelectric body 350 is PD2 in the opposite direction to PD1. As understood from this
structure, the piezoelectric element 30 of the present embodiment has a bimorph structure.
However, the present invention is not limited to this. For example, the piezoelectric element 30
may have a unimorph structure.
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[0023]
The structure of the piezoelectric element 30 will be described more specifically with reference
to FIG. 5. The first piezoelectric body 340 includes a plurality of first piezoelectric layers 342,
and the second piezoelectric body 350 includes a plurality of second piezoelectric bodies. It
consists of layers 352. In the predetermined direction (Z direction), the first piezoelectric layer
342 and the second piezoelectric layer 352 are stacked with the inactive layer 360 interposed
therebetween. The first electrode 344 is composed of a plurality of first electrode layers 346
corresponding to the first piezoelectric layer 342, and the second electrode 354 is composed of a
plurality of second electrode layers 356 corresponding to the second piezoelectric layer 352.
Each of the first electrode layers 346 is connected to a first terminal 322 made of a conductor,
and each of the second electrode layers 356 is connected to a second terminal 324 made of a
conductor.
[0024]
The third electrode 364 is composed of a plurality of third electrode layers 366. A part of the
third electrode layer 366 is provided corresponding to the first piezoelectric layer 342, and is
connected to the first ground terminal 332 made of a conductor. The other part of the third
electrode layer 366 is provided corresponding to the second piezoelectric layer 352 and is
connected to the second ground terminal 334 made of a conductor. The first ground terminal
332 and the second ground terminal 334 are connected to each other by a connecting portion
338 made of a conductor, whereby a third terminal 330 is formed.
[0025]
Referring to FIG. 2, the piezoelectric element 30 is connected to the connection member 40.
Conductors 41, 42 and 43 are formed on the connecting member 40. At one end of the
connection member 40, the conductor 41, the conductor 42 and the conductor 43 are
respectively connected to the first terminal 322, the second terminal 324 and the third terminal
330 by soldering or the like.
[0026]
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The conductor 41, the conductor 42 and the conductor 43 are connected to the drive device 70
at the other end of the connection member 40. The driving device 70 is attached to the inside of
a housing 82 of the electronic device 80, and supplies an electrical signal (driving signal) for
vibrating the piezoelectric element 30 to the piezoelectric element 30. In the present
embodiment, the connection member 40 is a flexible printed circuit (FPC). However, the present
invention is not limited to this. The connection member 40 and the drive device 70 may be
configured in any manner as long as the drive element can be supplied with a predetermined
drive signal. For example, the drive device 70 may be a dedicated device for supplying a drive
signal to the piezoelectric element 30. On the other hand, a control device that controls the
electronic device 80 may function as the drive device 70.
[0027]
Referring to FIGS. 3 and 4, the driving device 70 separates the main driving signal DSP, which is
one of the driving signals, and the sub driving signal DSS, which is another one of the driving
signals, for the piezoelectric element 30 from each other. Can be supplied to
[0028]
Referring to FIG. 3, the driving device 70 supplies a main driving signal DSP with the third
terminal 330 as a reference potential to the first terminal 322 and the second terminal 324
provided in the piezoelectric element 30.
The main drive signal DSP is an AC signal having a frequency corresponding to voice (i.e., sound
wave in the audible band). The main drive signal DSP1 is supplied to the first terminal 322 as a
main drive signal DSP. A main drive signal DSP2 obtained by reversing the phase of the main
drive signal DSP1 is supplied to the second terminal 324 as a main drive signal DSP. The main
drive signal DSP1 expands and contracts the first piezoelectric body 340 in the horizontal plane
(XY plane). The main drive signal DSP2 expands and contracts the second piezoelectric body 350
in the horizontal plane. Since the size in the longitudinal direction (X direction) of the first
piezoelectric body 340 in the present embodiment is larger than the size in the width direction (Y
direction), the first piezoelectric body 340 mainly expands and contracts in the longitudinal
direction. Similarly, the second piezoelectric body 350 expands and contracts mainly in the
longitudinal direction.
[0029]
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As described above, the polarization direction PD1 of the first piezoelectric body 340 and the
polarization direction PD2 of the second piezoelectric body 350 are opposite to each other. On
the other hand, the phases of the main drive signal DSP1 and the main drive signal DSP2 are
opposite to each other, and the amplitude and the wavelength coincide with each other.
Therefore, the first piezoelectric body 340 and the second piezoelectric body 350 expand and
contract in opposite directions in the longitudinal direction. Specifically, when the first
piezoelectric body 340 extends in the longitudinal direction, the second piezoelectric body 350
contracts in the longitudinal direction. When the first piezoelectric body 340 contracts in the
longitudinal direction, the second piezoelectric body 350 extends in the longitudinal direction. As
a result, each portion of the piezoelectric element 30 vibrates in a predetermined direction (Z
direction).
[0030]
Referring to FIG. 4, the driving device 70 supplies the sub driving signal DSS to the first terminal
322, the second terminal 324, and the third terminal 330 provided in the piezoelectric element
30. The sub drive signal DSS is an AC signal having a frequency corresponding to the ultrasonic
wave. The sub drive signal DSS1 is supplied to each of the first terminal 322 and the second
terminal 324 as a sub drive signal DSS. To the third terminal 330, a sub drive signal DSS2 in
which the phase of the sub drive signal DSS1 is reversed is supplied as a sub drive signal DSS.
The sub drive signal DSS1 causes the first piezoelectric body 340 and the second piezoelectric
body 350 to expand and contract mainly in the longitudinal direction (X direction).
[0031]
As described above, the polarization direction PD1 of the first piezoelectric body 340 and the
polarization direction PD2 of the second piezoelectric body 350 are opposite to each other.
Therefore, the first piezoelectric body 340 and the second piezoelectric body 350 expand and
contract in the same direction in the longitudinal direction by the same size. As a result, each
portion of the piezoelectric element 30 vibrates in the longitudinal direction.
[0032]
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The method of obtaining vibration in the longitudinal direction is not limited to the method
described above. For example, while supplying the voltage of the reference potential to the third
terminal 330, the sub drive signal DSS1 with the third terminal 330 as the reference potential is
supplied to each of the first terminal 322 and the second terminal 324. It is also good. Also by
this method, each portion of the piezoelectric element 30 vibrates in the longitudinal direction in
the same manner as the method described above.
[0033]
As described above, the sub drive signal DSS of the present embodiment is supplied to the first
terminal 322, the second terminal 324, and the third terminal 330. That is, the piezoelectric
element 30 is provided with a plurality of sub-terminals 320 including the first terminal 322, the
second terminal 324, and the third terminal 330. The sub terminal 320 is a terminal for
inputting the sub drive signal DSS to the piezoelectric element 30.
[0034]
Referring to FIG. 3, the main drive signal DSP of the present embodiment is supplied to the first
terminal 322 and the second terminal 324. That is, the piezoelectric element 30 is provided with
a plurality of main terminals 310 including the first terminal 322 and the second terminal 324.
The main terminal 310 is a terminal for inputting the main drive signal DSP to the piezoelectric
element 30.
[0035]
Referring to FIGS. 3 and 4, in the present embodiment, main terminal 310 is a subset of sub
terminal 320. Specifically, the first terminal 322 of the main terminal 310 is a terminal common
to the first terminal 322 of the sub terminal 320, and the second terminal 324 of the main
terminal 310 is a terminal common to the second terminal 324 of the sub terminal 320. It is.
However, the present invention is not limited to this, and the main terminal 310 may be provided
separately from the sub terminal 320.
[0036]
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Referring to FIG. 2, the fixed portion 54 of the support 50 is connected to the support portion 52
in the vicinity of one end of the support portion 52 in the longitudinal direction (X direction). The
fixed portion 54 connected in this manner hardly restricts the vibration of the support portion
52. In addition, the piezoelectric element 30 is fixed to the support 52 over the entire bottom
surface. Therefore, with the vibration of the piezoelectric element 30, the entire vibrating body
20 including the piezoelectric element 30 and the support portion 52 vibrates. The size in the
longitudinal direction (X direction) of the vibrating body 20 is larger than the size in the width
direction (Y direction). For this reason, the vibrating body 20 is more likely to vibrate so as to
undulate in the longitudinal direction than in the width direction, and is likely to stretch and
vibrate in the longitudinal direction.
[0037]
Referring to FIGS. 2 and 3, when the main drive signal DSP is input to the piezoelectric element
30, the vibrating body 20 is a standing wave traveling in the longitudinal direction (X direction)
and has amplitudes at both ends in the longitudinal direction. Perform a flexing motion that
maximizes. In other words, when the main drive signal DSP is input to the piezoelectric element
30, the vibrating body 20 vibrates to wave in a predetermined direction (Z direction). Referring
to FIG. 2, the fixing portion 84 of the housing 82 vibrates in response to the vibration of the
vibrating body 20. The vibration of the fixing portion 84 is transmitted to the main surface
member 88, and the main surface member 88 vibrates to generate an acoustic wave in the
audible range. That is, in the present embodiment, the vibration of the piezoelectric element 30 is
transmitted to the main surface member 88 through the support 50, the fixing portion 84, the
bottom portion 824 and the side portion 822 to vibrate the main surface member 88. Sound
waves in the audible range.
[0038]
With reference to FIGS. 2 and 6, the vibrating body 20 according to the present embodiment has
a resonance point, width direction (Y in the longitudinal direction (X direction), etc., of the wavelike vibration in the predetermined direction (Z direction). A plurality of resonance points such as
a resonance point attributable to the size in the direction (1) and a resonance point attributable
to the size in the predetermined direction (Z direction). For this reason, it is possible to generate
a sound wave having a sufficiently high sound pressure in a wide audible range of 200 Hz to 20
KHz.
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[0039]
Referring to FIGS. 2 and 4, when the sub drive signal DSS is input to the piezoelectric element 30,
the vibrator 20 stretches and vibrates in the longitudinal direction (X direction), and outputs
ultrasonic waves from both end portions in the longitudinal direction. Referring to FIG. 2, the
ultrasonic wave output from the vibrating body 20 is emitted to the outside of the electronic
device 80 via the main surface member 88, like the sound wave in the audible band. Referring to
FIG. 6, an ultrasonic wave having a sufficiently high sound pressure can be generated in the 30
to 40 KHz band.
[0040]
The ultrasonic waves generated by the piezoelectric element 30 are not only transmitted to the
main surface member 88 via the housing 82, but also mainly transmitted along the longitudinal
direction (X direction) of the vibrating body 20. The electronic device 80 of the present
embodiment does not have a member that blocks the transmission of the ultrasonic wave in the
longitudinal direction. Therefore, by adjusting the internal structure of the electronic device 80
according to the purpose such as distance measurement, the transmission path of the ultrasonic
wave can be variously adjusted. For example, by providing a member that reflects ultrasonic
waves in a desired direction on an extension along the longitudinal direction of the vibrating
body 20, the transmission path of the ultrasonic waves can be changed.
[0041]
Referring to FIG. 2, as described above, the vibrating body 20 of the sound generator 10
according to the present embodiment vibrates in a wavelike manner by the main drive signal DSP
(see FIG. 3). By this vibration, sound waves in the audible band can be output. In addition, the
vibrator 20 vibrates in an elastic manner by the sub drive signal DSS (see FIG. 4) to output an
ultrasonic wave. That is, the sound generator 10 can generate both sound waves and ultrasonic
waves in the audible band.
[0042]
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Since the vibrating body 20 of the present embodiment is long in the longitudinal direction (X
direction), ultrasonic waves of 30 to 40 KHz which is a relatively low frequency band are
generated as ultrasonic waves. The ultrasonic waves in this band can be detected by a
microphone (not shown) generally provided in the electronic device 80. Therefore, when making
a call using the electronic device 80 (mobile phone), the ultrasonic wave is used to measure the
distance between the caller's face and the main surface member 88, based on the measured
distance. The screen of the main surface member 88 can be erased.
[0043]
3 and 4, by superimposing and inputting the main drive signal DSP and the sub drive signal DSS
to the piezoelectric element 30, it is possible to simultaneously generate an acoustic wave and an
ultrasonic wave in the audible band. With reference to FIG. 2, sound waves in the audible band
may be used to allow calls while the screen of the major surface member 88 may be erased and
displayed depending on the distance measured using ultrasound. For example, the screen can be
displayed on the main surface member 88 when the main surface member 88 is temporarily
separated from the caller's face.
[0044]
Referring to FIG. 2, the support 50 of the present embodiment is formed of a metal plate such as
a stainless steel plate and easily vibrates in response to the vibration of the piezoelectric element
30. In other words, the vibrator 20 of the present embodiment vibrates favorably in response to
the main drive signal DSP (see FIG. 3) and the sub drive signal DSS (see FIG. 4).
[0045]
In the present embodiment, the piezoelectric element 30 is supported only by the support 50
directly fixed to the fixing portion 84 of the housing 82, and the housing member for housing the
piezoelectric element 30 in the inside of the electronic device 80 is used. There is no need to
provide it. Therefore, the piezoelectric element 30 can be accommodated in a slight internal
space of the electronic device 80. In addition, attenuation of the sound pressure by the housing
member can be prevented. That is, the sound generation device 10 of the present embodiment
can secure a sufficient sound pressure even when the electronic device 80 is miniaturized and
thinned.
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[0046]
According to the present embodiment, the support 50 is fixed to the fixing portion 84 in a state
close to a cantilever. Therefore, even when an impact is applied to the electronic device 80 due to
a drop or the like, the impact transmitted to the piezoelectric element 30 can be reduced.
However, the present invention is not limited to this. For example, the support 50 may be fixed to
the fixing portion 84 in a double-supported beam shape.
[0047]
The sound generation device 10 of the present embodiment can be further variously modified as
described below, in addition to the above-described modifications.
[0048]
For example, as described above, the sound generation device 10 of the present embodiment
includes the vibrating body 20 including the piezoelectric element 30 and the support portion 52
of the support 50.
However, as long as the vibration body 20 of the sound generation device 10 includes the
piezoelectric element 30, the support portion 52 may not be provided. On the other hand, the
vibrating body 20 may further include a member such as a weight for adjusting the frequency
characteristic of the sound pressure. In addition, the support portion 52 may be a member
separate from the fixed portion 54 of the support 50. The size of the piezoelectric element 30 in
the horizontal plane (XY plane) may be equal to or larger than the size of the support 52 in the
horizontal plane.
[0049]
With reference to FIGS. 7 and 8, the sound generation device 10A according to the first
modification includes the same piezoelectric element 30 and connection member 40 as the
present embodiment, and supports the support 50A different from the present embodiment.
Have. The support 50A includes a support 52A and a fixed portion 54A. As in the present
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embodiment, the piezoelectric element 30 is supported by the support portion 52A, and
constitutes the vibrating body 20A together with the support portion 52A. That is, the sound
generator 10A includes the vibrator 20A including the piezoelectric element 30 and the support
52A.
[0050]
As shown in FIG. 8, the support 52A of the support 50A has a flat plate shape, and extends on a
horizontal plane (XY plane) defined by the longitudinal direction (X direction) and the width
direction (Y direction) ing. The to-be-fixed portion 54A has a flat plate shape, and extends from
the support portion 52A in a predetermined direction (Z direction, vertical direction) orthogonal
to the support portion 52A. That is, the fixed portion 54A extends on the vertical plane (XZ
plane) defined by the longitudinal direction and the predetermined direction. The support portion
52A extends longer than the fixed portion 54A in the longitudinal direction.
[0051]
Referring to FIG. 7, the fixed portion 54A of the support 50A is fixed to the fixing portion 84A of
the electronic device 80 by adhesion, welding or the like. The fixing portion 84A in the present
modification is a part of the side portion 822 of the housing 82. In other words, in the attached
state in which the sound generation device 10 is attached to the housing 82, the support 50A is
fixed to the housing 82. In the mounted state, the support portion 52A of the support 50A is
separated from both the housing 82 and the main surface member 88.
[0052]
The vibrating body 20A of the sound generator 10A according to the present modification
vibrates in a wavelike manner by the main drive signal DSP (see FIG. 3). By this vibration, sound
waves in the audible band can be output. In addition, the vibrator 20A vibrates in a stretching
manner by the sub drive signal DSS (see FIG. 4) to output an ultrasonic wave. That is, the sound
generator 10A can generate both the sound wave and the ultrasonic wave in the audible band.
[0053]
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Referring to FIG. 8, the support 50 </ b> A of this modification is made of fiber reinforced plastic
such as glass fiber reinforced polyamide resin, and easily vibrates in response to the vibration of
the piezoelectric element 30. In other words, the vibrator 20A of the present embodiment
vibrates favorably in response to the main drive signal DSP (see FIG. 3) and the sub drive signal
DSS (see FIG. 4).
[0054]
The support 50A is not limited to the above-described materials, and can be formed of various
materials. For example, the support 50A may be formed by bending a metal in the same manner
as the support 50 (see FIG. 2) of the embodiment described above. However, from the viewpoint
of increasing the degree of freedom in shape design of the support 50A, the material of the
support 50A is preferably resin rather than metal. In this case, from the viewpoint of transmitting
the vibration of the piezoelectric element 30 favorably, the support 50A is preferably made of an
insulator having an elastic modulus of not less than 7.6 GPa and not more than 12.4 GPa as
defined in ISO 178. It is preferable that the size (thickness) in the predetermined direction (Z
direction) of is 0.2 mm or more and 2.0 mm or less.
[0055]
In the support 50A, the fixed portion 54A may extend from the support 52A in a direction
oblique to the support 52A. In other words, the fixed portion 54A may extend in the direction
intersecting the support portion 52A.
[0056]
Referring to FIG. 9, an acoustic generator 10B according to a second modification includes the
same piezoelectric element 30 and connecting member 40 as those of the present embodiment,
and includes a support 50B different from the present embodiment. . The support 50B extends
on the horizontal plane (XY plane) defined by the longitudinal direction (X direction) and the
width direction (Y direction). According to this modification, the entire support 50B functions as
the support portion 52B, and the bottom surface of the support 50B functions as the fixed
portion 54B. The support 50B can be formed of various materials. For example, the support 50B
may be a flat plate made of an elastic body, or may be a double-sided adhesive tape.
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[0057]
The piezoelectric element 30 is fixed on the support 50B (support 52B) in a predetermined
direction (Z direction), and is supported by the support 52B. The piezoelectric element 30
constitutes a vibrating body 20B together with the support portion 52B. That is, the vibrating
body 20B in the present modification includes the piezoelectric element 30 and the support
portion 52B. The bottom surface (the fixed portion 54B) of the support 50B is bonded and fixed
to the fixing portion 84B of the electronic device 80. The fixing portion 84 </ b> B in the present
modification is a part of the main surface member 88 of the electronic device 80. That is, in the
attached state where the sound generation device 10B is attached to the electronic device 80, the
fixed portion 54B is fixed to the main surface member 88. Further, in the attached state, the
support portion 52B is separated from the housing 82.
[0058]
The vibrating body 20B of the sound generation device 10B according to the present
modification vibrates in a wavy manner by the main drive signal DSP (see FIG. 3). By this
vibration, sound waves in the audible band can be output. In addition, the vibrating body 20B
vibrates by extension and contraction in response to the sub drive signal DSS (see FIG. 4) and
outputs an ultrasonic wave. That is, the sound generator 10B can generate both sound waves and
ultrasonic waves in the audible band. In particular, since the piezoelectric element 30 has a
bimorph structure, the support 50B (supporting portion 52B) can favorably transmit the
vibration of the piezoelectric element 30 to the main surface member 88.
[0059]
Referring to FIG. 10, an acoustic generator 10C according to the third modification includes the
same support 50B as the second modification, and includes a piezoelectric element 30C and a
connecting member 40C different from the second modification. . The piezoelectric element 30C
has a main piezoelectric body 382 and an auxiliary piezoelectric body 384. The sound generation
device 10C includes a vibrating body 20C including a piezoelectric element 30C and a support
50B (support portion 52B).
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[0060]
Referring to FIGS. 3 to 5 in conjunction with FIG. 10, each of the main piezoelectric body 382
and the sub piezoelectric body 384 has the same structure as the piezoelectric element 30. That
is, the main piezoelectric body 382 has a first piezoelectric body 340, a first electrode 344, a
second piezoelectric body 350, a second electrode 354 and a third electrode 364. The sub
piezoelectric member 384 has a first piezoelectric member 340, a first electrode 344, a second
piezoelectric member 350, a second electrode 354, and a third electrode 364 which are different
from the main piezoelectric member 382, respectively. Each of the main piezoelectric body 382
and the sub piezoelectric body 384 may be part of a common piezoelectric element 30C. On the
other hand, the main piezoelectric body 382 and the sub piezoelectric body 384 may be formed
separately from each other and connected in the longitudinal direction (X direction). In this case,
a connecting member may be provided between the main piezoelectric body 382 and the sub
piezoelectric body 384.
[0061]
The piezoelectric element 30C is provided with two main terminals 310 and three sub terminals
320 which are separate from the main terminals 310. The main terminal 310 includes a first
terminal 312 and a second terminal 314. The sub terminal 320 includes a first terminal 322
formed separately from the first terminal 312 of the main terminal 310, a second terminal 324
separately formed from the second terminal 314 of the main terminal 310, and a third terminal
And 330. In the main terminal 310, the first terminal 312 is connected to the first electrode 344
of the main piezoelectric body 382, and the second terminal 314 is connected to the second
electrode 354 of the main piezoelectric body 382. In the auxiliary terminal 320, the first terminal
322 is connected to the first electrode 344 of the auxiliary piezoelectric body 384, and the
second terminal 324 is connected to the second electrode 354 of the auxiliary piezoelectric body
384. The third terminal The reference numeral 330 is connected to the third electrode 364 of
the auxiliary piezoelectric member 384.
[0062]
Referring to FIG. 10, the connection member 40C is an FPC similar to the connection member 40
(see FIG. 9). However, in addition to the conductors 41, 42, 43, conductors 44, 45 are formed in
the connecting member 40C. At one end of the connecting member 40, the conductor 41 and the
conductor 42 are respectively connected to the first terminal 312 and the second terminal 314
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of the main terminal 310, and the conductor 43, the conductor 44 and the conductor 45 are
connected to the first of the subterminal 320. It is connected to the terminal 322, the second
terminal 324, and the third terminal 330, respectively.
[0063]
The sound generator 10C according to the present modification can generate both the sound
wave and the ultrasonic wave in the audible range, as in the sound generator 10B according to
the second modification (see FIG. 9). In detail, the vibrating body 20C of the sound generation
device 10C vibrates in a corrugated manner by the main drive signal DSP (see FIG. 3) supplied to
each of the main terminal 310 and the sub terminal 320. In addition, the vibrator 20C vibrates in
an elastic manner by the sub drive signal DSS (see FIG. 4) supplied to the sub terminal 320 to
output an ultrasonic wave.
[0064]
Referring to FIG. 11, an acoustic generator 10D according to the fourth modification includes the
same piezoelectric element 30 and connecting member 40 (see FIG. 2) as those of the abovedescribed embodiment, and is different from the above-described embodiment A support 50D is
provided. The support 50D includes a support 52D and a fixed portion 54D.
[0065]
The support 52D of the support 50D has a flat plate shape, and extends on a horizontal plane
(XY plane) defined by the longitudinal direction (X direction) and the width direction (Y
direction). The fixed portion 54D has a flat plate shape, and extends on a vertical plane (XZ
plane) defined by the width direction and a predetermined direction (Z direction). The fixed
portion 54D extends in a predetermined direction (Z direction) from an end of the support
portion 52D in the longitudinal direction.
[0066]
11 and 12, the piezoelectric element 30 is fixed on the support 52D of the support 50D in a
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predetermined direction (Z direction), and is supported by the support 52D. The piezoelectric
element 30 constitutes a vibrating body 20D together with the support portion 52D. The fixed
portion 54D of the support 50D is fixed to the fixing portion 84D of the housing 82 of the
electronic device 80 (see FIG. 2) by an adhesive 58D. The fixing portion 84D according to the
present modification is a part of the side portion 822 of the housing 82. The support portion
52D is apart from any of the housing 82 and the main surface member 88 (see FIG. 2).
[0067]
The sound generator 10C according to the present modification can generate both sound waves
and ultrasonic waves in the audible band, as in the sound generator 10 according to the abovedescribed embodiment (see FIG. 2).
[0068]
The present invention is not limited to the above-described embodiment and modifications, and
can be variously modified.
[0069]
For example, referring to FIGS. 3 and 4, in the above-described embodiment and modification, the
polarization direction PD1 of the first piezoelectric body 340 and the polarization direction PD2
of the second piezoelectric body 350 are opposite to each other.
However, the present invention is not limited to this, and the second piezoelectric body 350 may
be polarized in the same direction as the first piezoelectric body 340.
For example, the polarization direction of each of the first piezoelectric body 340 and the second
piezoelectric body 350 may be PD1.
[0070]
In this case, the drive device 70 supplies the voltage of the reference potential to the third
terminal 330 when generating the sound wave in the audible band, while the driving device 70
generates the sound wave of the first terminal 322 and the second terminal 324. The main drive
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signal DSP1 with the three terminals 330 as the reference potential may be supplied. By
supplying the main drive signal DSP in phase to each of the first piezoelectric body 340 and the
second piezoelectric body 350 polarized in the same direction, each portion of the piezoelectric
element 30 is arranged in the predetermined direction (Z direction). Vibrate.
[0071]
In addition, when generating the ultrasonic wave, the drive device 70 supplies the voltage of the
reference potential to the third terminal 330, and performs the sub-drive with the third terminal
330 as the reference potential with respect to the first terminal 322. The signal DSS1 may be
supplied. At this time, the driving device 70 supplies, to the second terminal 324, the sub driving
signal DSS2 which is the sub driving signal DSS2 with the third terminal 330 as a reference
potential and in which the phase of the sub driving signal DSS1 is reversed. Good. Each portion of
the piezoelectric element 30 is supplied with the sub drive signal DSS1 and the sub drive signal
DSS2 having phases opposite to each other with respect to the first piezoelectric member 340
and the second piezoelectric member 350 polarized in the same direction. Vibrates in the
longitudinal direction (X direction).
[0072]
When the first piezoelectric body 340 and the second piezoelectric body 350 are polarized in the
same direction, the main drive signal DSP may be supplied to the first terminal 322, the second
terminal 324, and the third terminal 330. . In this case, the sub drive signal DSS may be supplied
to the first terminal 322, the second terminal 324, and the third terminal 330. That is, in this
case, the piezoelectric element 30 is provided with a plurality of main terminals including the
first terminal 322, the second terminal 324 and the third terminal 330, and the first terminal
322, the second terminal 324 and the third A plurality of sub-terminals including three terminals
330 are provided. In this case, the entire main terminal functions as an auxiliary terminal.
[0073]
10, 10A, 10B, 10C, 10D Sound generator 20, 20A, 20B, 20C, 20D Vibrator 30, 30C Piezoelectric
element 310 Main terminal 312 First terminal 314 Second terminal 320 Secondary terminal 322
First terminal 324 Second terminal 330 third terminal 332 first ground terminal 334 second
ground terminal 338 connecting portion 340 first piezoelectric body 342 first piezoelectric layer
344 first electrode 346 first electrode layer 350 second piezoelectric body 352 second
piezoelectric layer 354 second electrode Two electrodes 356 Second electrode layer 360 Inactive
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layer 364 Third electrode 366 Third piezoelectric layer 382 Main piezoelectric body 384 Sub
piezoelectric body 40, 40C Connecting member 41, 42, 43, 44, 45 Conductor 50, 50A, 50B, 50D
Support 52, 52A, 52B, 52D Support 54, 54A, 54B, 54D Fixed part 56 screw 58D adhesive 70
drive 80 electronic apparatus 82 enclosure 822 side (side plate) 824 bottom (bottom plate) 84,
84A, 84B, 84D fixed part 88 main surface member
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