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DESCRIPTION JPWO2017110666

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DESCRIPTION JPWO2017110666
Abstract: An array speaker device (1A) comprises a substrate layer (11), a first electrode layer
(12), a piezoelectric element layer (13) and a second device layer, each having an equal
thickness, on a substrate having an equal thickness. The vibrator (20) configured by laminating
the electrode layers (14) in this order is arranged on one surface of the substrate. A hole for
outputting, in the thickness direction of the substrate, a sound wave generated by the vibration of
the vibrator (20) to which a voltage signal is applied through the first electrode layer (12) and
the second electrode layer (14). Is provided at a position corresponding to the vibrator (20). On
the inner peripheral wall of the hole, a scallop (S) in which the unevenness is repeated in the
thickness direction of the substrate is formed. (Selected figure) Figure 6
Speaker apparatus and method of manufacturing speaker apparatus
[0001]
The present invention relates to a speaker device and a method of manufacturing the speaker
device.
[0002]
BACKGROUND ART Conventionally, a speaker device has been disclosed in which piezoelectric
vibrators that emit sound waves generated by vibration are arranged (see, for example, Patent
Document 1).
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1
According to this speaker device, the plurality of piezoelectric vibrators are attached to and
attached to the substrate in a state of being pressed as much as possible against the support
member so that the height and the direction from the substrate are as even as possible. As a
result, it is possible to reduce directivity variations and phase deviations of the sound waves
radiated from the respective piezoelectric vibrators and to improve directivity.
[0003]
JP, 2013-157740, A
[0004]
In the above-described speaker device, the uniformity of the height and direction from the
substrate of each piezoelectric vibrator depends on the degree of pressing of the piezoelectric
vibrator.
However, since the degree of pressing varies, it is difficult to make the shape, size, and
orientation of the piezoelectric vibrator uniform on the order of microns to improve directivity.
[0005]
The present invention has been made under the above-described circumstances, and an object of
the present invention is to provide a speaker device and a method of manufacturing the speaker
device that can realize higher directivity.
[0006]
In order to achieve the above object, an array speaker device according to a first aspect of the
present invention comprises: a substrate having a uniform thickness; a base material layer having
a uniform thickness; a first electrode layer; The second electrode layer is stacked in this order,
and the vibrator is arranged on one surface of the substrate, and the other surface of the
substrate includes the first electrode layer and the second electrode. A hole for outputting in the
thickness direction of the substrate a sound wave generated by the vibration of the vibrator to
which a voltage signal is applied through a layer is provided at a position corresponding to the
vibrator, A scallop in which the unevenness is repeated in the thickness direction of the substrate
is formed.
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2
[0007]
In this case, a resonator that resonates with the vibration of the vibrator and brings a sound wave
output in the thickness direction of the substrate close to a plane parallel to the substrate; and
the resonator is provided at the center of the hole. A mounting portion may be provided, and a
scallop facing the scallop formed on the inner peripheral wall of the hole may be formed on the
outer peripheral wall of the mounting portion.
[0008]
The hole and the attachment portion are both cylindrical, the attachment portion is disposed
concentrically with the hole, and the resonator has a conical shape which is tapered toward the
vibrator, and It may be arranged concentrically with the hole and the mounting portion.
[0009]
The second electrode layer may be circular and disposed concentrically with the hole, the
attachment portion, and the resonator.
[0010]
A plurality of the vibrators may be provided, and the holes may be provided at positions
corresponding to the plurality of the vibrators, respectively.
[0011]
The transducers may be arranged at intersections of square grids on the substrate.
[0012]
The surrounding transducers may be evenly arranged on the circumference of a circle centered
on one transducer.
[0013]
The transducers may be arranged such that three transducers adjacent to each other are located
at the vertices of an equilateral triangle on the substrate.
[0014]
When a plurality of the substrates are laid, an outer edge in contact with the outer edge of
another adjacent substrate is provided with an unevenness that engages with the outer edge of
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the unevenness of the other substrate, and three adjacent vibrators straddle between the
substrates The vibrator may be provided on a convex portion of the outer edge such that the is
located at the vertex of an equilateral triangle congruent with the equilateral triangle.
[0015]
The first external terminal, which is an external terminal of the first electrode layer, and the
second electrode layer constituting the vibrator arranged on one surface of the substrate are
formed on the substrate so as to be electrically connected. And a second external terminal which
is an external terminal of the wiring pattern, wherein the first external terminal is provided on
another adjacent substrate when a plurality of the substrates are laid. The second external
terminal is provided at a position on the substrate facing the first external terminal, and the
second external terminal faces the second external terminal provided on another adjacent
substrate when a plurality of the substrates are laid. Provided at a position on the substrate.
[0016]
It may be fixed to a fixed object by a part of the piezoelectric element layer exposed on one
surface of the substrate.
[0017]
It may be fixed to the fixed object at a circular or rectangular portion disposed at an intersection
of a two-dimensional lattice formed so as to avoid the second electrode layer.
[0018]
It may be fixed to the fixed object in the whole part formed so as to avoid the second electrode
layer.
[0019]
It may be fixed to the fixation target in a two-dimensional grid-like part formed avoiding the
second electrode layer.
[0020]
According to a second aspect of the present invention, there is provided a method of
manufacturing an array speaker device, comprising the steps of: forming a first electrode layer
on a base material layer as an active layer of an SOI (Silicon On Insulator) substrate; Forming a
piezoelectric element layer on the electrode layer, forming the second electrode layer on the
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piezoelectric element layer, the base layer, the first electrode layer, and the piezoelectric element
Forming a vibrator including a layer and the second electrode layer on one surface of the
substrate by etching; turning over the substrate to turn over the voltage through the first
electrode layer and the second electrode layer Forming a hole for outputting in the thickness
direction of the substrate a sound wave generated by the vibration of the piezoelectric element
layer to which a signal is applied, at a position corresponding to the vibrator by deep etching on
the other surface of the substrate; including.
[0021]
According to the present invention, using the semiconductor manufacturing technology, the
vibrator and the hole for outputting the sound wave generated by the vibration of the vibrator in
the thickness direction of the substrate are formed on the substrate.
Thereby, the uniformity of the shape, the size, and the direction of the speaker constituted by the
vibrator and the hole can be enhanced.
As a result, higher directivity can be realized.
[0022]
It is a perspective view of the array speaker apparatus concerning Embodiment 1 of this
invention.
It is a top view of the array speaker apparatus of FIG. 1A.
It is AA sectional drawing of the array speaker apparatus of FIG. 1B.
It is a cross-sectional perspective view which expands and shows a speaker part.
It is a block diagram which shows the signal system connected to an array speaker apparatus.
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It is a figure which shows operation | movement (the 1) of a vibrator | oscillator when a voltage
is applied.
It is a figure which shows the operation | movement (the 2) of a vibrator | oscillator when a
voltage is applied.
It is sectional drawing which shows the scoop provided in the speaker part.
It is a directivity characteristic view which shows the directivity (the 1) of an array speaker
apparatus.
It is a directivity characteristic view which shows the directivity (the 2) of an array speaker
apparatus.
It is a flowchart which shows the manufacturing process of an array speaker apparatus.
It is sectional drawing of an SOI wafer.
It is a figure which shows a mode that the 1st electrode layer was laminated | stacked.
It is a figure which shows a mode that the piezoelectric element layer was laminated | stacked.
It is a figure which shows a mode that the piezoelectric element layer was patterned. It is a figure
which shows a mode that the 2nd electrode layer was formed into a film. It is a figure which
shows a mode that the 2nd electrode layer was patterned. It is a figure which shows a mode that
the board | substrate was turned over and the bottom face was protected. It is a figure which
shows a mode that the mask for deep etching etching was formed on the board | substrate. It is a
figure which shows a mode that deep digging etching was performed. It is a figure which shows a
mode that the board | substrate was etched. It is a figure which shows a mode that the BOX layer
was etched. It is a figure which shows a mode that the cup was attached. It is a perspective view
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of the array speaker apparatus which concerns on Embodiment 2 of this invention. It is a
directional characteristic view (the 1) of the array speaker apparatus of FIG. It is a directional
characteristic view (the 2) of the array speaker apparatus of FIG. It is a perspective view of the
array speaker apparatus which concerns on Embodiment 3 of this invention. It is a directional
characteristic view (the 1) of the array speaker apparatus of FIG. It is a directional characteristic
view (the 2) of the array speaker apparatus of FIG. It is a perspective view of the array speaker
apparatus which concerns on Embodiment 4 of this invention. FIG. 18 is a directivity
characteristic view (part 1) of the array speaker device of FIG. 17; FIG. 18 is a directivity
characteristic diagram (part 2) of the array speaker device of FIG. 17. It is a perspective view of
the array speaker apparatus which concerns on Embodiment 5 of this invention. It is a directional
characteristic view (the 1) of the array speaker apparatus of FIG. FIG. 20 is a directivity
characteristic view (part 2) of the array speaker device of FIG. 19; It is a top view of the array
speaker apparatus which concerns on Embodiment 6 of this invention. It is a bottom view of the
array speaker apparatus concerning Embodiment 6 of this invention. It is a top view of the array
speaker apparatus of FIG. It is a bottom view of the array speaker apparatus of FIG. It is a top
view of the array speaker apparatus which concerns on Embodiment 7 of this invention. It is a
bottom view of the array speaker apparatus concerning Embodiment 7 of this invention. FIG. 23C
is a top view of the array loudspeaker apparatus of FIG. It is a bottom view of the array speaker
apparatus of FIG. It is a top view of the array speaker apparatus which concerns on Embodiment
8 of this invention. It is a bottom view of the array speaker apparatus concerning Embodiment 8
of this invention. FIG. 25B is a top view of the array speaker apparatus of FIG. It is a bottom view
of the array speaker apparatus of FIG. It is a figure which shows the fixing method (the 1) of an
array speaker apparatus. It is a directional characteristic view (the 1) of the array speaker
apparatus of FIG. 27A.
It is a directional characteristic view (the 2) of the array speaker apparatus of FIG. 27A. It is a
figure which shows the fixing method (the 2) of an array speaker apparatus. It is a directional
characteristic view (the 1) of the array speaker apparatus of FIG. 28A. It is a directional
characteristic view (the 2) of the array speaker apparatus of FIG. 28A. It is a figure which shows
the fixing method (the 3) of an array speaker apparatus. It is a directional characteristic view (the
1) of the array speaker apparatus of FIG. 29A. It is a directional characteristic view (the 2) of the
array speaker apparatus of FIG. 29A. It is a figure which shows the fixing method (the 4) of an
array speaker apparatus. It is a directional characteristic view (the 1) of the array speaker
apparatus of FIG. 30A. It is a directional characteristic view (the 2) of the array speaker
apparatus of FIG. 30A. It is a figure which shows the fixing method (the 5) of an array speaker
apparatus. It is a directional characteristic view (the 1) of the array speaker apparatus of FIG.
31A. It is a directional characteristic view (the 2) of the array speaker apparatus of FIG. 31A.
[0023]
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7
Hereinafter, embodiments of the present invention will be described in detail with reference to
the drawings.
[0024]
Embodiment 1
First, the first embodiment of the present invention will be described.
[0025]
As shown in FIGS. 1A and 1B, the array speaker device 1A includes a substrate 2 which is a
support substrate of the entire device, and a plurality of speaker units 3 arranged in two rows
and two columns on the substrate 2. Each speaker unit 3 sets the thickness direction of the
substrate 2, that is, the + Z direction as the output direction of the sound wave. Each speaker unit
3 is manufactured in the same shape and size, in the same direction, using a MEMS (Micro
Electro Mechanical Systems) technology which is a semiconductor manufacturing technology,
and has high directivity. The sound wave includes an ultrasonic wave as well as voice and tone.
[0026]
The substrate 2 is a square flat plate having an even thickness, and is formed of, for example,
silicon (Si) or the like. The thickness of the substrate 2 is, for example, about 500 μm.
[0027]
As shown in FIG. 1B, the speaker units 3 are arranged on the substrate 2 at the apexes of a
square similar to the substrate 2. Therefore, the arrangement interval of the speaker units 3 in
the X-axis direction and the arrangement interval of the speaker units 3 in the Y-axis direction
are the same.
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[0028]
Holes 4 are provided at positions corresponding to the respective speaker units 3. Each hole 4
has a cylindrical shape, and outputs the sound wave generated by the speaker unit 3 in the
thickness direction of the substrate 2. At the center of each hole 4, an attaching portion 5 for
attaching a cup 15 described later is provided. The attachment portion 5 is a cylindrical member
disposed concentrically with the hole 4.
[0029]
As shown in FIG. 2 which is a cross section AA of FIG. 1B, the substrate 2 is formed of an SOI
(Silicon On Insulator) substrate composed of a support layer 10A, a BOX (Buried Oxide) layer
10B and a base material layer 11. ing. The support layer 10A is formed of silicon (Si) and has a
thickness of, for example, 525 μm. The BOX layer 10B is formed of a silicon oxide film (SiO 2)
and has a thickness of, for example, several μm. The base layer 11 is formed of silicon (Si). The
base material layer 11 is also called a Si active layer, and has a thickness of, for example, 150
μm. The SOI substrate is used in semiconductor manufacturing, and the thickness of each layer
is uniform.
[0030]
As shown in FIG. 2, in addition to the support layer 10A, the attachment portion 5, the BOX layer
10B, and the base layer 11, the array speaker device 1A includes the first electrode layer 12, the
piezoelectric element layer 13, and the first The second electrode layer 14 and the cup 15 are
provided. In FIG. 2, the second electrode layer 14, the piezoelectric element layer 13, the first
electrode layer 12, the base layer 11, the BOX layer 10B, and the support layer 10A (attachment
portion 5) are stacked in this order from the bottom. The thicknesses of the second electrode
layer 14, the piezoelectric element layer 13, the first electrode layer 12, the base material layer
11, the BOX layer 10B, and the support layer 10A (attachment portion 5) are uniform.
[0031]
The first electrode layer 12 is formed of a conductive member such as platinum or gold and has a
thickness of 1 μm or less. The first electrode layer 12 is formed on the entire substrate 2.
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9
[0032]
The piezoelectric element layer 13 is formed of a piezoelectric material that is electrostricted by
applying a voltage, and the thickness thereof is several μm. The piezoelectric element layer 13
expands and contracts when a voltage signal is applied. As the piezoelectric material, for
example, lead zirconate titanate (Pb (Zr, Ti) O3: PZT) or the like is adopted.
[0033]
The second electrode layer 14 is formed of a conductive member such as platinum or gold and
has a thickness of 1 μm or less. The second electrode layer 14 is provided for each of the
speaker units 3. The second electrode layer 14 is circular and disposed concentrically with the
hole 4, the mounting portion 5 and the cup 15.
[0034]
In the present embodiment, as shown in FIG. 3, the base material layer 11, the first electrode
layer 12, the piezoelectric element layer 13 and the second electrode layer 14 having the same
thickness are sequentially stacked in this order to form a vibrator. 20 are configured. The
vibrator 20 is attached to one surface (−Z surface) of the substrate 2. The speaker unit 3 is
configured by attaching the BOX layer 10B, the support layer 10A (including the attachment
portion 5), and the cup 15 on the vibrator 20.
[0035]
The cup 15 is a resonator that resonates with the vibration of the vibrator 20 and brings the
wave front of the sound wave output in the thickness direction of the substrate 2 close to a plane
parallel to the substrate 2. The cup 15 tapers as the hole 4 deepens. In other words, it has a
conical shape that tapers toward the vibrator 20 and is disposed concentric with the hole 4 and
the mounting portion 5. The cup 15 is made of, for example, aluminum or an aluminum alloy,
and the resonance frequency is 40 kHz. The band around 40 kHz is out of the human audible
range, and is considered to be a band that does not affect the sound.
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10
[0036]
The speaker unit 3 is connected to a signal system that supplies a voltage signal corresponding
to the sound to be reproduced. The signal system includes an audio signal output unit 30 and a
signal modulation unit 31, as shown in FIG.
[0037]
The audio signal output unit 30 outputs a voltage signal corresponding to the sound to be
reproduced by the array speaker device 1A. The frequency of this voltage signal is audible.
[0038]
The signal modulation unit 31 modulates the voltage signal output from the audio signal output
unit 30 at a predetermined modulation frequency. As the predetermined modulation frequency, a
frequency around 40 kHz which is a resonance frequency of the cup 15 is used. As a modulation
method of the signal modulation unit 31, for example, AM modulation (amplitude modulation) is
used.
[0039]
The voltage signal modulated by the signal modulation unit 31 is applied to the vibrator 20 as a
voltage signal between the second electrode layer 14 and the first electrode layer 12. The
vibrator 20 vibrates by this voltage signal to generate a sound wave.
[0040]
For example, as shown in FIG. 5A, when a positive voltage is applied to the second electrode layer
14 and a negative voltage is applied to the first electrode layer 12, the piezoelectric element
layer 13 is shown as an arrow. Stretch in the XY direction. However, since the base material layer
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11 does not extend, the vibrator 20 curves in a convex manner in the −Z direction.
[0041]
On the other hand, as shown in FIG. 5B, when a negative voltage is applied to the second
electrode layer 14 and a positive voltage is applied to the first electrode layer 12, the
piezoelectric element layer 13 moves in the X and Y directions as shown by the arrows. To
contract. However, since the base material layer 11 does not expand and contract, the vibrator
20 is curved in a convex manner in the + Z direction.
[0042]
Depending on the polarity of the piezoelectric element layer 13, the expansion and contraction
with respect to the applied voltage may be reversed. In this case, the vibrator 20 curves in the
opposite direction to the direction shown in FIGS. 5A and 5B.
[0043]
Since the voltage signal is a signal that oscillates by repeating positive and negative, the vibrator
20 repetitively oscillates the states of FIGS. 5A and 5B according to the voltage signal. This
vibration generates a sound wave.
[0044]
The hole 4 is provided at a position corresponding to the vibrator 20. A sound wave generated by
the vibration of the vibrator 20 to which a voltage signal is applied through the first electrode
layer 12 and the second electrode layer 14 travels in the hole 4 in the thickness direction of the
substrate 2. At this time, the cup 15 attached to the attachment portion 5 resonates with the
vibration of the vibrator 20 and converts the sound wave generated by the vibration of the
vibrator 20 from a spherical wave to a plane wave having a wave front parallel to the XY plane .
The sound wave (plane wave) whose wavefront is converted by the cup 15 is output from the
hole 4 and travels in the + Z direction.
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[0045]
By the way, the holes 4 of the substrate 2 are formed by deep etching as described later. As
shown in FIG. 6, scallops S in which the unevenness is repeated in the thickness direction of the
substrate 2 are formed on the inner peripheral wall of the hole 4. The scallop S is a concavities
and convexities in the depth direction formed in accordance with the repetition of etching in
deep etching, and the number thereof depends on the number of times of etching repetition
described later. The scallop S is formed on the outer peripheral wall of the mounting portion 5 so
as to face the scallop S formed on the inner peripheral wall of the hole 4.
[0046]
As shown in FIG. 7A, in the directivity characteristic when the modulation frequency of the
voltage signal is 40 kHz, the peak in the + Z direction (the direction of 0 degrees) is sharp. This
indicates that the directivity is high. This is because the respective speakers are formed to have
the same shape and size and the same direction by the semiconductor manufacturing technology.
[0047]
Further, as shown in FIG. 7B, in the directivity characteristic in the case where the modulation
frequency of the voltage signal is 43.6 kHz, the peak in the + Z direction is sharper. This indicates
that the directivity is further enhanced. It is considered that this is because the overall resonant
frequency of the array speaker device 1A is close to 43.6 kHz.
[0048]
Next, a method of manufacturing the array speaker device 1A will be described. The array
speaker device 1A is manufactured using the MEMS technology as described above.
[0049]
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13
When manufacturing the array speaker device 1A, as shown in FIG. 8, first, an SOI wafer is
prepared (step S1). As shown in FIG. 9A, an SOI substrate refers to a support substrate (which
becomes the support layer 10A) made of a semiconductor substrate, a BOX layer (which becomes
the BOX layer 10B) which is a buried oxide film on the support substrate, and a BOX layer. It is a
substrate having a laminated structure including a silicon (SOI) layer (base material layer 11)
which is an upper semiconductor layer, and is a wafer including an oxide film.
[0050]
The SOI wafer is formed by the following procedure. First, oxygen molecules are implanted from
the surface of a silicon crystal by ion implantation into a bulk silicon wafer having a uniform
thickness, and oxidized by high heat to form an insulating film of silicon oxide in the silicon
crystal. Then, another unprocessed bulk wafer is bonded to the surface with a uniform thickness,
and the previous wafer is peeled and created. The exfoliation thickness is controlled by the
distance from the surface of hydrogen ions previously implanted deep in the oxide film, and the
exfoliation surface is finished by chemical mechanical polishing (CMP). In this manner, an SOI
wafer in which the thickness of the portion corresponding to the support layer 10A, the BOX
layer 10B and the base layer 11 is uniform is formed.
[0051]
Subsequently, the first electrode layer 12 is formed on the active layer (base material layer 11) of
the SOI wafer by, for example, a sputtering method using a sputtering apparatus (step S2). FIG.
9B shows that the first electrode layer 12 is formed on the base material layer 11.
[0052]
Subsequently, the piezoelectric element layer 13 which is a PZT film is formed by sputtering
using, for example, a sputtering apparatus (step S3). FIG. 9C shows that the piezoelectric element
layer 13 is formed on the first electrode layer 12.
[0053]
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14
Subsequently, patterning of the piezoelectric element layer 13 is performed by photolithography
(step S4). Here, the four corners of the piezoelectric element layer 13 are removed by etching,
and the piezoelectric element layer 13 is patterned so that the first electrode layer 12 is exposed
from the removed portion.
[0054]
More specifically, a photoresist is applied on the piezoelectric element layer 13 using a coater or
the like, and a pattern of the shape of the piezoelectric element layer 13 is transferred onto the
photoresist by the exposure device. The transferred pattern is developed by a developer or the
like and etched in an etching apparatus to complete the patterning of the piezoelectric element
layer 13. As a result, as shown in FIG. 10A, the external terminals 12A are formed at the four
corners of the first electrode layer 12.
[0055]
Subsequently, the second electrode layer 14 is formed on the piezoelectric element layer 13 by a
sputtering method using a sputtering apparatus (step S5). As shown in FIG. 10B, the second
electrode layer 14 is formed on portions of the piezoelectric element layer 13 and the first
electrode layer 12.
[0056]
Subsequently, the second electrode layer 14 is patterned by photolithography (step S6). Here, the
periphery of the second electrode layer 14 is removed by etching, the second electrode layer 14
is patterned, and the second electrode layer 14 is formed at a position corresponding to the
vibrator 20.
[0057]
More specifically, a photoresist is applied on the second electrode layer 14 using a coater or the
like, and the pattern in the shape of the second electrode layer 14 is transferred to the
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15
photoresist by the exposure device. The transferred pattern is developed by a developer or the
like and etched in an etching apparatus to complete patterning, and the second electrode layer
14 is formed. Thereby, as shown to FIG. 10C, the circular-shaped 2nd electrode layer 14 is
formed.
[0058]
Subsequently, the substrate 2 is turned over to protect the active layer (base material layer 11)
side (step S7). At this time, as shown in FIG. 11A, a protective film 16 is formed on the lower first
electrode layer 12, the piezoelectric element layer 13 and the second electrode layer.
[0059]
Subsequently, a mask 17 for deep etching is formed and mounted on the support layer 10A (step
S8). For example, quartz (SiO 2) is used for such a mask 17. Thereby, as shown to FIG. 11B, the
mask 17 with which the hole was opened only in the area | region in which 10 A of support
layers and the attachment part 5 are formed is installed on 10 A of support layers.
[0060]
Subsequently, deep etching is performed on the support layer 10A (step S9). Deep etching is also
called Bosch process. In the Bosch process, by repeating isotropic etching, protective film
formation (passivation) and anisotropic etching several times, as shown in FIG. 11C, deep (high
aspect ratio) holes 4 are formed and the attachment portion is formed. 5 is formed. In this
process, scallops (scallops) S are formed on the inner peripheral wall of the hole 4 and the outer
peripheral wall of the mounting portion 5.
[0061]
In isotropic etching, for example, SF6 gas is used. The portion (the portion of the hole 4) of the
support layer 10A not covered with the mask 17 is etched by the F-based radical generated from
the SF6 gas.
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[0062]
In addition, C4F8 plasma is used for forming a protective film, and C4F8 is deposited as a
protective film. A protective film is thereby formed on the entire support layer 10A including the
holes 4.
[0063]
Also, in anisotropic etching, the protective film formed on the bottom of the isotropic etching is
removed by causing F-based reactive ions (F <+> ions) to strike the bottom of the hole 4 at high
speed. .
[0064]
The portion where the protective film is removed is again subjected to isotropic etching to
expand the hole 4 in the depth direction.
Such steps are repeated to advance deep etching. When the depth reaches the BOX layer 10B,
the deep etching is finished. The pitch of the scallop S and the depth of the unevenness can be
determined by adjusting the reaction time or the like in each process.
[0065]
Subsequently, the protective film 16 covering the active layer (base material layer 11) side is
removed (step S10). Thereby, the cross section around the speaker unit 3 is in the state as shown
in FIG. 12A.
[0066]
Subsequently, the BOX layer 10B on the bottom of the hole 4 which has been a stopper for deep
etching is removed by etching using an etching apparatus (step S11). Thereby, the cross section
around the speaker unit 3 is in the state as shown in FIG. 12B.
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17
[0067]
Subsequently, the cup (resonator) 15 is attached to the attachment portion 5 with an adhesive
(step S12). Thereby, the periphery of the speaker unit 3 is in the state as shown in FIG. 12C.
Thereafter, the SOI wafer is diced and cut into a square. Thereby, the array speaker apparatus 1A
is almost completed.
[0068]
As described above, in the array speaker device 1A, the plurality of speaker units 3 are formed by
layering layers of uniform thickness. As a result, the size, shape, and orientation of each speaker
unit 3 are substantially the same. Therefore, if the same voltage signal is input to each speaker
unit 3, all the generated sound waves are output in the same direction. As a result, higher
directivity can be realized.
[0069]
As described above in detail, according to the present embodiment, the vibrator 20 and the
sound wave generated by the vibration of the vibrator 20 on the substrate 2 are output in the
thickness direction of the substrate 2 using the semiconductor manufacturing technology. Form a
hole 4. Thereby, the uniformity of the shape, the size, and the direction of the speaker unit 3
configured by the vibrator 20 and the hole 4 can be enhanced. As a result, it is possible to reduce
the variation in the direction of the sound waves output from the respective speaker units 3 and
the phase difference, and to realize higher directivity.
[0070]
Moreover, according to the present embodiment, it is also possible to make the array speaker
device 1A thin. For example, the overall thickness can be about 600 μm.
[0071]
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18
Second Embodiment Next, a second embodiment of the present invention will be described. As
shown in FIG. 13, the array speaker device 1 </ b> B according to the second embodiment
includes nine speaker units 3 (oscillators 20). The nine speaker units 3 (vibrator 20) are disposed
on the intersections of the square grids. Also in the present embodiment, the cup 15 is attached
to the attachment portion 5 of each speaker unit 3.
[0072]
In the present embodiment, the arrangement intervals of the speaker units 3 in the X-axis
direction and the Y-axis direction are uniform. Therefore, the sound waves generated by the
array speaker device 1B are uniform in the thickness direction of the substrate 2, and high
directivity can be realized.
[0073]
FIG. 14A shows the directivity when the modulation frequency of the voltage signal is 40 kHz,
and FIG. 14B shows the directivity when the modulation frequency of the voltage signal is 43.6
kHz. As shown in FIGS. 14A and 14B, also in the array speaker device 1B according to this
embodiment, the peak in the + Z direction is sharp. The peak in the + Z direction is sharper when
the modulation frequency is 43.6 kHz, which is close to the resonant frequency of the entire
array speaker device 1B.
[0074]
Third Embodiment Next, a third embodiment of the present invention will be described. As shown
in FIG. 15, an array speaker apparatus 1C according to the third embodiment includes nine
speaker units 3 (vibrator 20) as in the second embodiment. , Cup 15 is not attached.
[0075]
Even in this case, as shown in FIG. 16A (modulation frequency 40 kHz) and FIG. 16B (modulation
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frequency 45.4 kHz), the directivity in the thickness direction of the substrate 2 is extremely
sharp. Also in this case, the peak in the + Z direction is larger when the modulation frequency is
45.4 kHz, which is close to the resonance frequency of the entire array speaker device 1C.
[0076]
Fourth Embodiment Next, the fourth embodiment of the present invention will be described. As
shown in FIG. 17, an array speaker device 1D according to the fourth embodiment includes seven
speaker units 3 (vibrator 20). The remaining speaker units 3 (vibrator 20) around the periphery
are equally arranged on the circumference of a circle centered on one speaker unit 3 (vibrator
20).
[0077]
Also in this case, as shown in FIG. 18A (modulation frequency 40 kHz) and FIG. 18B (modulation
frequency 37.6 kHz), the directivity of the sound wave in the thickness direction (+ Z direction) of
the substrate 2 is extremely sharp.
[0078]
Embodiment 5
A fifth embodiment of the present invention will now be described. As shown in FIG. 19, in the
array speaker device 1E according to the fifth embodiment, the substrate 2 has a circular shape.
The remaining loudspeaker units 3 (vibrator 20) are equally arranged on the circumference of a
circle centered on one loudspeaker unit 3 (vibrator 20), as in the fourth embodiment.
[0079]
Even in this case, as shown in FIG. 20A (modulation frequency 40 kHz) and FIG. 20B (modulation
frequency 38.2 kHz), the directivity in the thickness direction of the substrate 2 is extremely
sharp. Also in this case, the directivity is sharper in the case where the modulation frequency is
38.2 kHz close to the resonance frequency of the entire array speaker device 1E.
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[0080]
Sixth Embodiment A sixth embodiment of the present invention will now be described. As shown
in FIG. 21A, in the array speaker device 1F according to the sixth embodiment, 27 speaker units
3 (vibrator 20) are arranged on the substrate 2. In the array speaker device 1F according to the
sixth embodiment, as shown in FIG. 21B, the speaker unit is arranged such that the three speaker
units 3 (vibrator 20) adjacent to each other are positioned at the vertices of an equilateral
triangle on the substrate 2. 3 (vibrator 20) are arranged.
[0081]
As shown in FIG. 21B, on the bottom surface of the array speaker device 1F, a circular second
electrode layer 14 is formed at a position corresponding to the vibrator 20 on the piezoelectric
element layer 13, and the second electrode layer A wiring pattern 14A connecting between 14 is
connected. The wiring patterns 14A are connected to the external terminals 14B disposed at the
four corners of the substrate 2. The external terminal 14B is connected to the signal modulation
unit 31 of FIG. 4, and a voltage signal is applied to the second electrode layer 14 through the
external terminal 14B and the wiring pattern 14A.
[0082]
As shown in FIG. 21B, in the XY plane, the distance between the adjacent speaker units 3
(vibrator 20) is equal, so the directivity in the thickness direction of the substrate 2 can be
further enhanced.
[0083]
In this array speaker device 1F, as shown in FIG. 22A, a plurality of substrates 2 can be laid on
the XY plane with the speaker portions 3 directed in the same direction.
In this way, the overall volume can be increased. In this case, as shown in FIG. 22B, when a
plurality of substrates 2 are laid out, the external terminals 12A are positioned on the substrate 2
facing the external terminals 12A provided on the other adjacent substrate 2 (four corners of the
substrate 2 Provided in).
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[0084]
Similarly, the external terminals 14B are provided at positions (four corners of the substrate 2)
on the substrate 2 facing the external terminals 14B provided on another adjacent substrate 2
when a plurality of the substrates 2 are laid. When the external terminals 12A and 14B are
electrically connected between the substrates 2 by using a jumper wire or the like, a parallel
circuit of the piezoelectric element layers 13 can be constructed across the substrates 2. This can
simplify the circuit for sending the voltage signal.
[0085]
Embodiment 7 A seventh embodiment of the present invention will now be described. As shown
in FIG. 23A, in the array speaker device 1G according to the seventh embodiment, 25 speaker
units 3 are arranged on the substrate 2. The speaker units 3 are arranged at intersections of
square grids on the substrate 2.
[0086]
As shown in FIG. 23B, in the −Z plane of the array speaker device 1G, a circular second
electrode layer 14 is formed on the piezoelectric element layer 13 at a position corresponding to
the vibrator 20, and the second electrode A wiring pattern 14A connecting the layers 14 is
connected. The wiring pattern 14A is connected to the external terminal 14B. The signal
modulation unit 31 of FIG. 4 is connected to the external terminal 14B, and a voltage signal is
applied to the second electrode layer 14 through the external terminal 14B and the wiring
pattern 14A.
[0087]
In the XY plane, since the distances between the speaker units 3 (vibrator 20) adjacent in the Xaxis direction and the Y-axis direction are equal, directivity in the thickness direction of the
substrate 2 can be further enhanced.
[0088]
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In this array speaker device 1G, as shown in FIG. 24A, a plurality of substrates 2 can be laid on
the XY plane with the speaker portions 3 directed in the same direction.
In this way, the overall volume can be increased. In this case, as shown in FIG. 24B, when a
plurality of substrates 2 are laid out, the external terminals 12A are positioned on the substrate 2
facing the external terminals 12A provided on the other adjacent substrate 2 (four corners of the
substrate 2 Provided in).
[0089]
Similarly, the external terminals 14B are provided at positions (four corners of the substrate 2)
on the substrate 2 facing the external terminals 14B provided on another adjacent substrate 2
when a plurality of the substrates 2 are laid. By connecting the external terminals 12A and 14B
of the adjacent substrates 2 with a jumper wire or the like, a parallel circuit of the piezoelectric
element layers 13 can be constructed across the substrates 2. Therefore, the circuit for sending
the voltage signal can be simplified.
[0090]
Eighth Embodiment An eighth embodiment of the present invention will now be described. As
shown in FIGS. 25A and 25B, in the array speaker device 1H according to the eighth
embodiment, 30 speaker units 3 are arranged. In the array speaker device 1H according to the
eighth embodiment, the speaker unit 3 (vibrator 20) is arranged such that three speaker units 3
(vibrator 20) adjacent to each other are positioned at the apex of an equilateral triangle on the
substrate 2. It is arranged.
[0091]
In the present embodiment, as shown in FIG. 26A, when a plurality of substrates 2 are laid, an
outer edge in contact with the outer edge of another adjacent substrate 2 is provided with an
unevenness that engages with the outer edge of the unevenness of the other substrate 2 There is.
Further, in the present embodiment, three adjacent speaker units 3 (vibrator 20) straddling
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between the substrates 2 are disposed on one substrate 2 and three adjacent speaker units 3
(vibrator 20). Loudspeaker portion 3 (vibrator 20) is provided on the convex portion of the outer
edge so as to be located at the vertex of the equilateral triangle formed by and the congruent
equilateral triangle.
[0092]
As shown in FIGS. 25B and 26B, the external terminals 12A are provided at positions (four
corners) on the substrate 2 opposed to the external terminals 12A provided on another adjacent
substrate 2 when a plurality of substrates 2 are laid. It is done. Similarly, when a plurality of
substrates 2 are laid out, the external terminals 14B are located on the substrate 2 facing the
external terminals 14B provided on the adjacent other substrate 2 (the middle point of the outer
edge of the substrate 2 and the corner of the unevenness Provided in). The external terminals
14B of the adjacent substrates 2 can be connected by a jumper wire or the like to form a parallel
circuit of the piezoelectric element layers 13 straddling between the substrates 2. Therefore, the
circuit for sending voltage signals to the plurality of array speaker devices 1H can be simplified.
[0093]
As described above, since the arrangement intervals of the speaker units 3 (the vibrators 20) are
uniform across the plurality of adjacent substrates 2, the volume can be increased and the
directivity can be improved. it can.
[0094]
Embodiment 9
A ninth embodiment of the present invention will now be described. The array speaker apparatus
according to the ninth embodiment is characterized in that the apparatus is fixed to the fixing
target. The fixing target includes a metal (for example, aluminum or brass), a resin base or the
like.
[0095]
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As shown in FIG. 27A, in the array speaker device 1I according to the ninth embodiment, the
fixing portion 40 is formed in a part of the piezoelectric element layer 13 exposed to one surface
(−Z surface) of the substrate 2. In array speaker device 1I according to the present embodiment,
fixing portion 40 is arranged at an intersection of a two-dimensional lattice formed so as to avoid
second electrode layer 14. The shape of each fixing portion 40 is circular. At this fixing portion
40, the array speaker device 1H is fixed to an object to be fixed by adhesive or screwing.
[0096]
FIG. 27B shows the directivity when the modulation frequency of the voltage signal is 40 kHz,
and FIG. 27C shows the directivity when the modulation frequency of the voltage signal is 39.6
kHz, which is the overall resonance frequency of the array speaker device 1I. The characteristics
are shown. As shown in FIGS. 27B and 27C, the directivity of sound in the + Z direction is
extremely sharp.
[0097]
Embodiment 10 Next, a tenth embodiment of the present invention will be described. The array
speaker device according to the tenth embodiment is characterized in that the device is fixed to a
fixed object.
[0098]
As shown in FIG. 28A, in the array speaker device 1J according to the tenth embodiment, the
fixing portion 41 is formed in a part of the piezoelectric element layer 13 exposed to one surface
(−Z surface) of the substrate 2. In array speaker device 1J according to the present embodiment,
fixing portion 41 is arranged at an intersection of a two-dimensional lattice formed so as to avoid
second electrode layer 14. The shape of each fixing portion 41 is rectangular. The array speaker
device 1J is fixed to the object to be fixed with an adhesive or the like by the fixing portion 41.
[0099]
FIG. 28B shows the directivity when the modulation frequency of the voltage signal is 40 kHz,
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and FIG. 28C shows the directivity when the modulation frequency of the voltage signal is 39.6
kHz which is the overall resonance frequency of the array speaker device 1J. The characteristics
are shown. As shown in FIGS. 28B and 28C, the directivity of the sound in the + Z direction is
sharp. The peak is slightly sharper in FIG. 28C in which the modulation frequency is 39.6 kHz.
[0100]
Embodiment 11 An eleventh embodiment of the present invention will now be described. The
array speaker device according to the present embodiment is characterized in that the device is
fixed to a fixed object.
[0101]
As shown in FIG. 29A, in the array speaker device 1K according to the present embodiment, the
fixing portion 42 is formed by a part of the piezoelectric element layer 13 exposed on one
surface of the substrate 2. The fixing portion 42 covers the whole of the piezoelectric element
layer 13 formed so as to avoid the second electrode layer 14. A slight margin is provided
between the fixing portion 42 and the second electrode layer 14.
[0102]
FIG. 29B shows the directivity when the modulation frequency of the voltage signal is 40 kHz,
and FIG. 29C shows the directivity when the modulation frequency of the voltage signal is 39.6
kHz, which is the overall resonance frequency of the array speaker device 1K. The characteristics
are shown. As shown in FIGS. 29B and 29C, the directivity of sound in the + Z direction is
extremely sharp. The peak is slightly sharper when the modulation frequency is 39.6 kHz.
[0103]
Embodiment 12 A twelfth embodiment of the present invention will now be described. The array
speaker device according to the twelfth preferred embodiment is characterized in that the device
is fixed to an object to be fixed.
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[0104]
As shown in FIG. 30A, in the array speaker device 1L according to the present embodiment, the
fixing portion 43 is formed by a part of the piezoelectric element layer 13 exposed on one
surface (−Z surface) of the substrate 2. Is bonded and fixed to the fixed object. The fixing portion
43 has a square lattice shape formed so as to avoid the second electrode layer 14.
[0105]
FIG. 30B shows the directivity when the modulation frequency of the audio signal is 40 kHz, and
FIG. 30C shows the directivity when the modulation frequency of the audio signal is 37 kHz
which is the overall resonance frequency of the array speaker device 1L. The characteristics are
shown. As shown in FIGS. 30B and 30C, the directivity of sound in the + Z direction is extremely
sharp. The peak is sharper when the modulation frequency is 37 kHz.
[0106]
Thirteenth Embodiment A thirteenth embodiment of the present invention will now be described.
The array speaker device according to the thirteenth embodiment is characterized in that the
device is fixed to a fixed object.
[0107]
As shown in FIG. 31A, in the array speaker device 1M according to the thirteenth embodiment,
the fixing portion 44 is formed by a part of the piezoelectric element layer 13 exposed on one
surface of the substrate 2, and the fixing portion 44 is a fixing target. It is glued and fixed. The
fixing portion 44 is formed at an intersection of a square grid shape formed so as to avoid the
second electrode layer 14, and the shape thereof is circular. The size of the fixing portion 44 is as
large as possible with the gap (margin) with the second electrode layer 14 as a minimum.
[0108]
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31B shows the directional characteristics when the modulation frequency of the voltage signal is
40 kHz, and FIG. 31C shows that the modulation frequency of the voltage signal is 40.6 kHz
which is the overall resonance frequency of the array speaker device 1M. The directional
characteristics of the time are shown. As shown in FIGS. 31B and 31C, the directivity of sound in
the + Z direction is extremely sharp.
[0109]
Comparing the directivity characteristics of the array speaker devices 1I to 1M with different
fixing methods, the directivity of the most output sound when fixed to the fixation target by the
fixing portion 40 of the array speaker device 1J according to the ninth embodiment The result
was higher.
[0110]
About the specific processing method used at each process in the manufacturing method of the
array speaker apparatus which concerns on said each embodiment, for example, film-forming of
each layer, patterning, an etching method, etc., it can change suitably.
For example, depending on the material to be used, it is possible to adopt a film formation
method on a semiconductor wafer suitable for the material.
[0111]
The various materials and dimensions in 1A to 1M of the array speaker device described above
are merely examples, and the present invention is not limited thereto. The size can be
appropriately adjusted according to the various devices to be mounted.
[0112]
Although the piezoelectric material is PZT in the above embodiments, other piezoelectric
materials may be used. Other piezoelectric materials such as BaTiO 3 and PbTiO 3 may be used,
or piezoelectric single crystals such as quartz or lithium niobate may be used. In addition,
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piezoelectric polymer films such as zinc oxide (ZnO), vinylidene fluoride, and trifluoroethylene
polymer may be used.
[0113]
In each of the above embodiments, the holes 4 are circular, but they may be rectangular or other
shapes. The attachment portion 5 and the cup 15 may have other shapes such as a polygon as
long as they can convert the wave front of the sound wave into a plane wave.
[0114]
In each of the above embodiments, the modulation scheme of the audio signal is AM modulation,
but an FM scheme (frequency modulation scheme) may be adopted.
[0115]
In each of the above-described embodiments, although the target manufactured using the MEMS
technology is the array speaker apparatus in which the single speaker units 3 are arrayed, the
present invention is not limited to this.
The speaker device of the present invention may be a device having only one speaker.
[0116]
The present invention is capable of various embodiments and modifications without departing
from the broad spirit and scope of the present invention. In addition, the embodiment described
above is for explaining the present invention, and does not limit the scope of the present
invention. That is, the scope of the present invention is indicated not by the embodiments but by
the claims. And, various modifications applied within the scope of the claims and the meaning of
the invention are considered to be within the scope of the present invention.
[0117]
The present application claims priority based on Japanese Patent Application No. 2015-254860
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29
filed on December 25, 2015, and the specification of Japanese Patent Application No. 2015254860 is herein incorporated by reference. The claims, the entire drawing, is incorporated by
reference.
[0118]
The present invention can be applied to a speaker that is attached to various electric devices
such as a mobile device such as a smartphone and generates voice and the like that require high
directivity.
[0119]
1A, 1 B, 1 C, 1 D, 1 E, 1 F, 1 G, 1 H, 1 I, 1 J, 1 K, 1 L, 1 M Array speaker device, 2 boards, 3
speakers, 4 holes, 5 mounting portions, 10 A support layer, 10 B BOX layer , 11 base material
layer, 12 first electrode layer, 12A external terminal, 13 piezoelectric element layer, 14 second
electrode layer, 14A wiring pattern, 14B external terminal, 15 cup, 16 protective film, 17 mask,
20 vibrator , 30 audio signal output unit, 31 signal modulation unit, 40, 41, 42, 43, 44 fixed unit,
S scallop
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