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JP2005340961

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DESCRIPTION JP2005340961
The present invention provides a sound wave receiving apparatus capable of reducing noise and
improving the S / N ratio of a received signal. A sound wave receiving apparatus 1 has a
rectangular parallelepiped box-like apparatus main body 2 provided with a sound wave
introducing hole 5 penetrating to the front and back of a front wall, and a sound wave receiving
that converts sound wave received through the sound wave introducing hole 5 into a reception
signal. The two electrode plates 8 and 9 which are separated from each other in the direction
intersecting the opening surface 5a of the sound wave introducing hole 5 and have the part 6a
and the output terminals 8a and 9a for taking out the reception signal separately A sound wave
receiving element 6 provided and a shield pattern 12 for shielding formed on at least the inner
side surface of the device body 2 are provided, and the electrode plate 8 is electrically connected
to the shield pattern 12. [Selected figure] Figure 1
Sound wave receiver
[0001]
The present invention relates to a sound wave receiving apparatus that receives sound waves.
[0002]
In recent years, as a sound wave receiving apparatus, one using a minute sound wave receiving
element manufactured using a semiconductor manufacturing technology has been provided.
[0003]
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As a sound wave receiving element used in such a sound wave receiving device, a diaphragm
having one end fixed to the frame so as to be swingable in the thickness direction is provided,
and a movable electrode provided on the other end of the diaphragm There is provided a silicon
capacitor microphone provided with a capacitor composed of a fixed electrode provided on the
frame opposite to the movable electrode, and detecting a change in position of the diaphragm
due to a sound wave by a change in capacitance of the capacitor (Patent Document 1).
JP 2001-518246 A (FIG. 1)
[0004]
As described above, in recent years, miniaturization of the acoustic wave receiving element has
progressed, and for example, the above-mentioned silicon condenser microphone has a size of
less than 1 mm.
However, along with the miniaturization of the acoustic wave receiving element, the received
signal obtained from the acoustic wave receiving element is also a minute signal, and if the noise
from the surroundings is large, the received signal is buried in the noise and correct reception
There was a problem that a signal could not be obtained. Therefore, it has been desired to
improve the S / N ratio of the reception signal output from the sound wave receiving element by
reducing the noise from the surroundings.
[0005]
The present invention has been made in view of the above-described point, and an object thereof
is to provide a sound wave receiving apparatus capable of reducing noise and improving the S /
N ratio of a received signal.
[0006]
In order to solve the above-mentioned subject, in invention of Claim 1, a box-like device main
body provided with a sound wave introduction hole which penetrates front and back of front
wall, and converts sound wave received through the sound wave introduction hole into a received
signal Sound wave receiving element, an output terminal for taking out the received signal, and a
sound wave receiving element comprising a conductive layer formed along the opening face of
the sound wave introducing hole, and a shield for shielding formed on at least the inner surface
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of the device body And a pattern, and the conductive layer is electrically connected to the shield
pattern.
[0007]
According to the first aspect of the present invention, noise generated in the received signal
output from the sound wave receiving element can be reduced by the shield pattern provided on
the device body.
In addition, since the conductive layer formed along the opening face of the sound wave
introduction hole is electrically connected to the shield pattern to make the same potential as the
shield pattern, the conductive layer is the shield in the sound wave introduction hole where the
shield pattern can not be formed. Will play a role.
As a result, the shield performance of the sound wave receiving apparatus is further improved,
and noise generated in the reception signal output from the sound wave reception element can
be reduced to improve the S / N ratio of the reception signal.
[0008]
According to the invention of claim 2, in addition to the constitution of claim 1, an air vent hole
communicating the inside and the outside of the device body is provided in the rear wall of the
device body.
[0009]
According to the second aspect of the invention, even if the air in the device expands and
contracts due to a change in ambient temperature, the air flows in and out from the air vent
holes, so that the pressure change in the device is suppressed.
As a result, it is possible to prevent stress from being generated in the sound wave receiving
portion of the sound wave receiving element due to a change in pressure in the device, thereby
preventing fluctuation in the reception sensitivity of the sound wave receiving element. In
addition, since the air venting hole is provided on the rear wall of the device main body which is
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a portion used when mounting the sound wave receiving device on the mounting substrate, it is
possible to suppress the decrease in shielding performance due to the air venting hole.
[0010]
In the invention according to claim 3, in addition to the configuration according to claim 1 or 2,
at least the preamplifier for amplifying the reception signal outputted from the sound wave
receiving element is accommodated in the device body. It was set as the sound wave receiving
device characterized by the above.
[0011]
According to the invention of claim 3, since the preamplifier is housed and arranged in the
apparatus main body, the reception signal outputted from the sound wave receiving element is
amplified in the shielded apparatus main body.
Therefore, it is possible to suppress mixing of noise into a minute received signal before
amplification, and it is possible to improve the S / N ratio of the received signal.
[0012]
According to the invention of claim 4, in addition to the configuration according to any one of
claims 1 to 3, the sound wave receiving element is fixed to the apparatus main body by using a
conductive adhesive. It was a sound wave receiver.
[0013]
According to the invention of claim 4, the conductive adhesive plays a role of a shield, and noise
can be reduced also in the peripheral portion of the sound wave introduction hole.
[0014]
In the invention according to claim 5, in addition to the configuration according to any one of
claims 1 to 4, the sound wave receiving element has an output terminal and is separated in a
direction crossing the opening surface of the sound wave introducing hole. According to another
aspect of the present invention, there is provided a sound wave receiving apparatus comprising:
two electrode plates overlapping the sound wave introduction hole; and the conductive layer is
an electrode plate closer to the sound wave introduction hole among the both electrode plates.
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[0015]
According to the invention of claim 5, of the two electrode plates of the sound wave receiving
element, the electrode plate closer to the sound wave introducing hole is a conductive layer
electrically connected to the shield pattern, so this electrode plate is the other The electrode plate
serves as a shield that protects the electrode plate from noise, and this electrode plate can reduce
noise passing through the sound wave introduction hole.
Thereby, the shielding performance in the sound wave introduction hole can be improved.
[0016]
In the invention according to claim 6, in addition to the configuration according to any one of
claims 1 to 4, the sound wave receiving element has an output terminal and is separated in a
direction crossing the opening surface of the sound wave introducing hole. A shield layer
provided between the electrode plate and the sound wave introduction hole, the shield layer
being insulated from each other, and the conductive layer being the shield layer; According to
another aspect of the present invention, there is provided a sound wave receiving apparatus
characterized in that
[0017]
According to the invention of claim 6, since the shield layer insulated from each other with the
two electrode plates of the sound wave receiving element becomes a conductive layer electrically
connected to the shield pattern, the shield layer causes noise in both electrode plates. It plays a
role of a shield to protect from the noise, and the noise passing through the sound wave
introduction hole can be reduced by this shield layer.
Thereby, the shielding performance in the sound wave introduction hole can be improved.
In addition, since received signals can be extracted from both electrode plates, differential signal
extraction becomes possible, and a high S / N ratio can be obtained.
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[0018]
In the invention according to claim 7, in addition to the configuration according to any one of
claims 1 to 6, the sound wave receiving element is provided with an electrode plate on the main
surface of a supporting substrate made of a semiconductor substrate, and the electrode plate An
electrode pad, which is an output terminal electrically connected, is exposed on the main surface
side of the support substrate, and is mounted facedown on the apparatus body using the
electrode pad. .
[0019]
According to the invention of claim 7, the acoustic wave receiving element is mounted facedown
on the main body of the apparatus by using the electrode pad which is the output terminal
electrically connected to the electrode plate provided on the main surface of the support
substrate consisting of a semiconductor substrate. For example, since connection by wire
bonding is not required, the size and thickness of the apparatus main body can be reduced.
[0020]
In the invention according to claim 8, in addition to the configuration according to any one of
claims 1 to 7, the device body has the sound wave introducing hole in the front wall and a box
having an opening over the entire surface of the rear wall. The acoustic wave receiving device is
characterized in that the acoustic wave receiving device comprises a cover having a shape of a
circle and a part of a mounting substrate on which components using the acoustic wave receiving
element are mounted, and a base on which the cover is attached.
[0021]
According to the invention of claim 8, the back wall portion of the device main body of the sound
wave receiving device is shared by a part of the mounting substrate on which the sound wave
receiving device is mounted, thereby reducing the number of parts of the sound wave receiving
device and reducing the assembly cost. Can be
[0022]
In the invention according to claim 9, in addition to the configuration according to any one of
claims 1 to 7, the device main body includes a flat cover having the sound wave introduction
hole, and an opening covering the entire surface of the front wall. It is a box having a base, the
opening being closed by the cover, and the cover is a three-dimensional circuit-formed substrate
in which a circuit pattern is formed on a flat molded article provided with the sound wave
introducing hole. According to another aspect of the present invention, there is provided a sound
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wave receiving apparatus characterized in that
[0023]
According to the invention of claim 9, since the three-dimensional circuit-formed substrate in
which the circuit pattern is formed on the flat molded product provided with the sound wave
introducing hole is used as a cover, the flexibility of the shape of the sound wave introducing
hole and its peripheral portion can do.
[0024]
In the invention according to claim 10, in addition to the constitution according to claim 9, the
base is a three-dimensional circuit-formed substrate in which a circuit pattern is formed on a
box-like molded article having an opening extending over the entire front wall. And a sound wave
receiver characterized by
[0025]
According to the invention of claim 10, since the three-dimensional circuit formation substrate in
which the circuit pattern is formed on the box-like molded product having the opening over the
entire front wall is used as a base, the number of parts of the sound wave receiving device can be
reduced. Cost can be reduced.
[0026]
In the present invention, in addition to the effect that the noise generated in the reception signal
outputted from the sound wave receiving element can be reduced by the shield pattern provided
in the device main body, the conductive layer plays the role of a shield in the sound wave
introduction hole where the shield pattern can not be formed. As a result, the shield performance
of the sound wave receiving apparatus is further improved, and noise generated in the received
signal output from the sound wave receiving element can be reduced to improve the S / N ratio
of the received signal.
[0027]
Hereinafter, an embodiment of a sound wave receiving apparatus of the present invention will be
described using FIGS. 1 to 9.
[0028]
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First Embodiment As shown in FIGS. 1A and 1B, the sound wave receiving device 1 of the present
embodiment is a rectangular parallelepiped box-like device main body provided with a sound
wave introducing hole 5 penetrating to the front and back of the front wall. 2 and a sound wave
receiving portion 6a for converting a sound wave received through the sound wave introducing
hole 5 into a received signal, and an output terminal 8a, 9a for taking out the received signal, and
a direction crossing the opening surface 5a of the sound wave introducing hole 5 An acoustic
wave receiving element 6 having two electrode plates 8 and 9 which are separated from each
other and overlapping the acoustic wave introducing hole 5, and a shield pattern 12 for shielding
formed on at least the inner side surface of the apparatus main body 2; 8 are electrically
connected to the shield pattern 12.
In FIG. 1A, the shield pattern 12 is omitted, and the acoustic wave receiving element 6 is partially
omitted.
The same applies to FIGS. 3, 4A, and 5 to 9 below.
[0029]
As shown in FIG. 1 (a), the device body 2 is a box-like rectangular parallelepiped box having a flat
cover 3 provided with a sound wave introducing hole 5 and an opening covering the entire
surface of the front wall. The base 4 is closed by a cover 3.
The cover 3 closes the opening of the base 4 to be the front wall of the apparatus main body 2,
and the cover 3 is formed with a sound wave introducing hole 5 made of, for example, a
cylindrical hole penetrating to the front and back.
The base 4 is formed in a rectangular box shape having a bottom 4a to be a rear wall of the
apparatus main body 2 and a side wall 4b erected from the bottom 4a and having an opening
extending over the entire front wall.
Further, in the apparatus main body 2 including the cover 3 and the base 4, a shield pattern 12
for shielding is formed on the inner side surface, and an output for outputting the reception
signal output from the sound wave receiving element 6 to the outside Circuit patterns (not
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shown) are formed.
[0030]
The sound wave receiving element 6 is, as shown in the schematic cross sectional view of FIG. 1
(b), along the opening surface 5a of the sound wave introducing hole 5 in the main surface 11b
of the support substrate 11 provided with the concave diaphragm 11a at the approximate center.
The two electrode plates 8 and 9 having the output terminals 8a and 9a and separated in the
direction intersecting the opening surface 5a of the sound wave introducing hole 5 and
overlapping the sound wave introducing hole 5; , 9 and a ferroelectric thin film 10 made of a
piezoelectric material.
[0031]
More specifically, the acoustic wave receiving element 6 is a piezoelectric sensor as shown in FIG.
2A and has the following structure.
That is, such an acoustic wave receiving element 6 has an insulating film layer 17 made of SiO 2
and a first electrode which is a platinum electrode on a supporting substrate 11 formed of a
silicon wafer having, for example, an SOI (Silicon On Insulator) structure. Insulating film layer for
short-circuit protection of the plate 8, the ferroelectric thin film 10 made of PZT (lead zirconate
titanate) which is a piezoelectric material, and the ferroelectric thin film layer 10 and area
control of the second electrode plate 9 And a second electrode plate 9 which is a platinum
electrode.
The supporting substrate 11 has the Si semiconductor active layer 16 on the surface of the Si
semiconductor substrate 14 having the insulating film layer 13 of SiO 2 on the back surface via
the insulating film layer 15 of SiO 2, and these insulating film layers 13 and 15. And a part of the
Si semiconductor substrate 14 is removed to form a diaphragm part 11a.
The output terminal 8a is electrically connected to the first electrode plate 8 through the contact
hole 10a formed in the ferroelectric thin film 10, and the output terminal 9a is electrically
connected to the second electrode plate 9 It is done.
A sound wave receiving portion 6a is formed of the first electrode plate 8, the ferroelectric thin
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film 10 and the second electrode plate 9 stacked on the diaphragm portion 11a.
According to the sound wave receiving element 6 configured as described above, when the sound
wave is incident on the sound wave receiving unit 6a, the piezoelectric effect is generated in the
ferroelectric thin film 10 by the stress of the sound wave, and the voltage generated thereby is
output terminal 8a, A sound wave can be detected by taking out as a reception signal from 9a.
[0032]
As shown in FIG. 1B, the sound wave receiving element 6 has the sound wave receiving portion 6
a facing the sound wave introducing hole 5 of the cover 3, and the supporting substrate 11 is
made of an adhesive such as epoxy resin on the back surface of the cover 3. It is mounted on the
cover 3 by being fixed.
In addition, the output terminal 8a of the first electrode plate 8 closer to the sound wave
introduction hole 5 of the both electrode plates 8 and 9 is electrically connected to the portion of
the shield pattern 12 formed on the cover 3 using the wire 7a. Connected to
Further, the output terminal 9a of the second electrode plate 9 is electrically connected to the
output circuit pattern (not shown) by using a wire 7b.
[0033]
Then, the acoustic wave receiving element 6 is housed and arranged in the apparatus main body
2 by attaching the cover 3 on which the acoustic wave receiving element 6 is mounted as
described above to the base 4 so as to close the opening of the base 4 The acoustic wave receiver
1 is configured by electrically connecting the portions formed on the cover 12 of the pattern 12
and the circuit pattern for output and the portions formed on the base 4 separately.
[0034]
According to the sound wave receiving apparatus 1 of the present embodiment, noise generated
in the reception signal output from the sound wave receiving element 6 can be reduced by the
shield pattern 12 provided in the apparatus main body 2.
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In addition, of the two electrode plates 8 and 9 of the sound wave receiving element, the first
electrode plate 8 closer to the sound wave introducing hole 5 is electrically connected to the
shield pattern 12 and has the same potential as the shield pattern 12. In the sound wave
introducing hole 5 where the shield pattern 12 can not be formed, the first electrode plate 8
plays a role of a shield for protecting the second electrode plate 9 from noise. Thereby, the shield
performance of the sound wave receiving device 1 is improved, noise generated in the received
signal output from the sound wave receiving element 6 can be reduced, and the S / N ratio of the
received signal can be improved.
[0035]
By the way, the sound wave receiving element 6 used in the sound wave receiving apparatus 1 of
the present invention is not limited to the pressure sensor as shown in FIG. 2 (a), but uses the
condenser microphone 19 as shown in FIG. 2 (b). be able to. Such a condenser microphone 19 is
made of a silicon wafer, and a back plate portion 21 which is a first electrode plate provided on
the support substrate 20 so as to straddle the hole 20 a and the support substrate 20 in which
the hole 20 a is formed. A contact hole 22 for electrically connecting the output terminal 21a to
the back plate portion 21, and an insulating film layer 23 made of silicon oxide and silicon
nitride provided with a hole portion 23a for exposing the surface of the back plate portion 21; ,
And the back plate portion 21 electrically connected to the diaphragm portion 25 which is a
second electrode plate made of, for example, polysilicon and having an air gap 24 between the
back plate portion 21 and the hole portion 23a. And an output terminal 25 a electrically
connected to the diaphragm 25. Further, the back plate portion 21 is provided with a plurality of
air holes 21 b for flowing air into and out of the air gap 24. The diaphragm unit 25 and the back
plate unit 21 form a sound wave receiving unit 26 which is a variable gap capacitor. The
condenser microphone 19 configured as described above is driven by applying a DC bias voltage
between the output terminals 21a and 25a, and when a sound wave is incident on the sound
wave receiving unit 26 in this state, the diaphragm part is generated by the stress of the sound
wave. As a result, the distance between the diaphragm 25 and the back plate 21 changes, and the
capacitance of the sound wave receiver 26 changes. Therefore, the acoustic wave can be detected
by taking out the change of the capacitance as the reception signal from the output terminals
21a and 25a.
[0036]
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Furthermore, as shown in FIGS. 3A and 3B, an air vent hole 28 can be provided in the bottom 4a
of the base 4 to be the rear wall of the device body 2 to allow the inside and the outside of the
device body 2 to communicate. According to such an air vent hole 28, for example, when the air
in the sound wave receiver 1 is expanded due to a temperature rise when the sound wave
receiver 1 is used, the expanded air flows out from the air vent hole 28 to receive the sound
wave. A change in pressure in the device 1 can be suppressed. Also, conversely, when the air in
the sound wave receiving device 1 contracts due to a temperature drop, the air flows into the
sound wave receiving device 1 from the air vent holes 28 to suppress the pressure change in the
sound wave receiving device 1. it can. That is, even if the air in the device body 2 expands and
contracts due to the change in the ambient temperature, the air flows in and out from the air
vent 28 so that the pressure change in the sound wave receiving device 1 is suppressed. As a
result, stress is generated in the sound wave receiving unit 6 a of the sound wave receiving
element 6 due to a change in pressure in the sound wave receiving device 1, and fluctuation in
the reception sensitivity of the sound wave receiving element 6 can be prevented. In addition,
since the air venting hole 28 is provided in the bottom 4 a of the base 4 which is a portion used
when mounting the sound wave receiving device 1 on the mounting substrate, suppression of
shield performance deterioration due to the air venting hole 28 is suppressed. it can.
[0037]
Further, as shown in FIG. 4A, the bottom 4a of the base 4 which is the back wall of the apparatus
body 2 is shared by a part of the mounting substrate 30 on which the components 29, 29 using
the acoustic wave receiving element 6 are mounted. You may do it. In this case, the device body
2 comprises a cover 3 and a side wall 4b, a box-shaped cover 3 'having a sound wave introducing
hole 5 in the front wall and an opening over the entire back wall, and a sound wave receiving
element 6 It consists of a part of the mounting substrate 30 on which the parts 29, 29 to be used
are mounted, and is composed of the base 4 'to which the cover 3' is attached. Of course, a shield
pattern (not shown) is formed on the inner side surface of the apparatus body 2 including the
cover 3 'and the base 4'. Thus, the number of parts of the sound wave receiving device 1 can be
reduced by using the bottom 4a which is the rear wall of the device body 2 of the sound wave
receiving device 1 as one part of the mounting substrate 30 on which the sound wave receiving
device 1 is mounted. Assembling cost can be reduced.
[0038]
Furthermore, a shield layer 31 as shown in FIG. 4B can be provided to the above-described sound
wave receiving element 6. That is, the sound wave receiving element 6 is provided with two
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electrode plates 8 and 9 which have output terminals 8 a and 9 a and are separated in a direction
intersecting the opening surface 5 a of the sound wave introducing hole 5. Between the electrode
plates 8 and 9 and the sound wave introducing hole 5, the electrode plates 8 and 9 are
electrically insulated from each other by the insulating film layer 27, and are conductive layers
formed along the opening surface 5 a of the sound wave introducing hole 5. A shield layer 31 is
provided. The shield layer 31 is electrically connected to a portion of the shield pattern 12
formed on the cover 3 using a wire 7c.
[0039]
As described above, since the shield layer 31 insulated from each other with the two electrode
plates 8 and 9 of the sound wave receiving element 6 is electrically connected to the shield
pattern 12, the shield layer 31 can be used as both electrode plates 8 and 9. The shield layer 31
plays a role of shielding the noise from the noise, and the shield layer 31 can reduce the noise
passing through the sound wave introduction hole 5. Thereby, the shielding performance in the
sound wave introduction hole 5 can be improved. In addition, since received signals can be taken
out from both electrode plates 8 and 9, it is possible to take out signals in a differential system,
and a high S / N ratio can be obtained.
[0040]
Second Embodiment The sound wave receiving apparatus 1 of the present embodiment is
characterized in the apparatus main body 2 compared with the above-described first
embodiment, and the other structure is substantially the same as that of the first embodiment.
The explanation is omitted.
[0041]
That is, as shown in FIG. 5A, the apparatus main body 2 of the sound wave receiving apparatus 1
according to the present embodiment uses the cover 3 and the base 4 as three-dimensional
circuit formation boards (MID (Molded Interconnect Device)). Here, the cover 3 is a threedimensional circuit-formed substrate in which a circuit pattern such as the shield pattern 12 is
formed on a flat molded product provided with the sound wave introduction hole 5 having a
circular cross section penetrating to the front and back. A three-dimensional circuit-formed
substrate in which a circuit pattern such as a shield pattern 12 is formed on a rectangular boxlike molded product having an opening over the entire front wall, in which a bottom 4a and a
side wall 4b are integrally formed. .
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As said molded article, resin-made and ceramic-made things can be used.
[0042]
A method of manufacturing such a three-dimensional circuit forming substrate will be described
by taking the cover 3 as an example. First, a flat resin or ceramic provided with the sound
introducing hole 5 which is a hole having a circular cross section penetrating through the front
and back by injection molding. A molded article is formed, and then a copper thin film is formed
on the surface of the molded article by sputtering. Then, a laser is used to electrically insulate a
portion necessary as a copper thin film circuit from an unnecessary portion. Next, copper is
thickened to a necessary portion of the copper thin film circuit by copper electroplating, and
then the unnecessary portion of the copper thin film is etched away. Thereafter, nickel and gold
are formed on the thickened portion of copper by electroplating to form a circuit pattern,
whereby a three-dimensional circuit-formed substrate is completed.
[0043]
According to the present embodiment, since the cover 3 is a circuit board on which the threedimensional circuit is formed, the freedom of the shape of the sound wave introducing hole 5 and
its peripheral portion can be improved, and the base 4 is a circuit board on which the threedimensional circuit is formed. The number of parts can be reduced, and the assembly cost can be
reduced.
[0044]
On the other hand, as shown in FIG. 5B, the preamplifier 32 is wire-bonded to the output circuit
pattern (not shown) provided on the bottom 4a of the base 4 using the wires 7d and 7d in the
apparatus body 2. You may store and arrange.
In this case, since the preamplifier 32 for amplifying the received signal output from the sound
wave receiving element 6 is housed and arranged in the apparatus main body 2, the received
signal output from the sound wave receiving element 6 is shielded in the shielded apparatus
main body 2. It is amplified. Therefore, it is possible to suppress mixing of noise into a minute
received signal before amplification, and it is possible to improve the S / N ratio of the received
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signal. In this case, the location of the preamp 32 is not limited to the bottom 4a, and may be
placed on the cover 3 or the side wall 4b and stored in the apparatus main body 2 depending on
the situation. The connection method is not limited to the bond, and a suitable connection
method can be selected according to the situation. In addition, various devices other than the
preamplifier 32 can be accommodated and arranged in the device main body 2 as needed.
[0045]
Further, in the above-mentioned sound wave receiving apparatus 1, the sound wave receiving
element 6 is fixed to the cover 3 using an adhesive such as epoxy resin, but as shown in FIG. It
may be fixed to the cover 3 using an adhesive 36. In this case, the conductive adhesive 36 is
electrically connected to the shield pattern 12 to play a role of a shield, and noise can be reduced
also in the peripheral portion of the sound wave introduction hole 5. In addition, in this example,
the support substrate 11 of the sound wave receiving element 6 is provided with conductivity,
and the support substrate 11 is electrically connected to the conductive adhesive 36 to be at the
same potential. Will play a role of This can further reduce noise.
[0046]
Alternatively, instead of wire bonding the acoustic wave receiving element 6 to the cover 3, facedown mounting may be performed. In this case, the acoustic wave receiving element 6 includes
an electrode plate on the main surface 11b of the support substrate 11 made of a semiconductor
substrate such as a silicon wafer, for example, and an electrode pad which is an output terminal
electrically connected to the electrode plate is the support substrate It is formed so as to be
exposed on the side of the main surface 11b of 11, and this electrode pad is used for face-down
mounting on the cover 3 of the apparatus main body 2 as shown in FIG. 6 (b). As described
above, the acoustic wave receiving element 6 can be face-down mounted on the apparatus main
body 2 using the electrode pad electrically connected to the electrode plate provided on the main
surface 11 b of the support substrate 11. Therefore, for example, since connection by wire
bonding is not required, the size and thickness of the apparatus main body 2 can be reduced.
[0047]
By the way, as described above, in the present embodiment, since the cover 3 is a threedimensional circuit forming substrate, various shapes can be easily obtained by injection molding
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as the shapes of the sound wave introducing hole 5 and its peripheral portion. As shown to 7 (a),
the sound wave introduction hole 5 can be made into the taper shape expanded from the back
surface side of the cover 3 to the surface side. According to this, the sound wave can be easily
received by the sound wave introducing hole 5, and the sound wave can be efficiently collected
to the sound wave receiving unit 6a, and the sound collection effect can be improved. In FIG. 7,
the angle of the tapered shape of the sound wave introducing hole 5 is indicated by an angle A,
and the angle of the tapered shape of the diaphragm portion 11 a of the sound wave receiving
element 6 is indicated by an angle B. At this time, although the angle A is smaller than the angle
B, the sound wave introducing hole 5 shown in FIG. 7A is a cover when the angle A is smaller
than the angle B as shown in FIG. 7C. For example, the cover 3 is deformed by the load applied
when the acoustic wave receiving element 6 is mounted by wire bonding, or the wire bonding is
excessive at the time of wire bonding. There is a risk of adverse effects such as the inability of
sound wave vibration to work. On the contrary, when the angle A is larger than the angle B as
shown in FIG. 7 (d), the size of the opening on the surface side of the cover 3 of the sound wave
introducing hole 5 becomes smaller, and the sound collecting effect is reduced. . Therefore, when
making the sound wave introduction hole 5 into a tapered shape, as shown in FIG. 7 (b), if the
angle A and the angle B are made the same size, the efficiency of the mountability and the sound
collecting effect is made the best. Can.
[0048]
On the other hand, when the sound wave incident on the sound wave receiver 6a has a high
frequency of, for example, about 100 kHz, the wavelength is as short as about 3.4 mm, causing
the following problem. That is, when the sound wave reflected by the inner circumferential
surface of the sound wave introducing hole 5 is incident on the sound wave receiving portion 6a,
the sound wave and the sound wave directly incident on the sound wave receiving portion 6a
without being reflected on the inner circumferential surface of the sound wave introducing hole
5 And the phase difference between the sound waves will occur. Such a phase difference appears
more prominently as the wavelength is shorter, and as a result, there is a problem that the
received waveform at the sound wave receiving unit 6a is disturbed. In order to solve such a
problem, it is necessary to reduce the reflection of the sound wave on the inner peripheral
surface of the sound wave introduction hole 5, and in the cover 3 shown in FIG. 5 is formed in a
hole shape which is expanded stepwise from the back side to the front side of the cover 3.
According to the sound wave introducing hole 5, since the inner peripheral surface of the sound
wave introducing hole 5 has a surface parallel to the surface of the cover 3, the sound wave
incident on this surface is reflected in the substantially opposite direction to the incident
direction It will be done. Therefore, it is possible to prevent the sound wave reflected by the inner
circumferential surface of the sound wave introducing hole 5 from being incident on the sound
wave receiving portion 6a, and thereby the above problem can be solved. Alternatively, as shown
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in FIG. 8 (b), the inner peripheral surface of the sound wave introducing hole 5 may be
roughened to provide the rough surface portion 33. According to the rough surface portion 33,
the sound wave is directed in various directions. Since the light is reflected in a dispersed
manner, the reflection of the sound wave is reduced, which also solves the above-mentioned
problems. Further, as shown in FIG. 8C, the concave portion 34 for disposing the sound wave
receiving element 6 can be provided in the peripheral portion of the sound wave introducing
hole 5 on the back surface side of the cover 3. In this case, since the thickness dimension of the
sound wave introducing hole 5 is shortened, the number of sound waves reflected by the inner
peripheral surface of the sound wave introducing hole 5 is reduced, whereby the above problem
can be solved. In addition, by forming the induction portion 34a having, for example, a tapered
shape at the opening edge of the recess 34, the sound wave receiving element 6 can be easily
mounted. On the other hand, as shown in FIG. 8D, a convex portion 35 surrounding the sound
wave introduction hole 5 may be provided on the periphery of the sound wave introduction hole
5 on the back surface side of the cover 3 on which the sound wave receiving element 6 is
mounted. According to this convex portion 35, when the sound wave receiving element 6 is
mounted on the cover 3 with an adhesive such as epoxy resin, the adhesive does not flow into the
sound wave receiving portion 6a, whereby the adhesive receives the sound wave. It is possible to
prevent the sound wave receiving unit 6a from being adversely affected by flowing into the unit
6a.
[0049]
Furthermore, a plurality of sound wave introduction holes 5 may be provided on the cover 3. For
example, as shown in FIG. 9A, the sound wave introduction holes 5 are formed in a row of 3 rows
and 3 columns arrayed on the cover 3 at a predetermined pitch. can do. Then, by providing the
sound wave receiving elements 6 corresponding to the respective sound wave introducing holes
5 in such a cover 3, sound wave reception capable of detecting the incident direction of the
sound wave from the difference in the incident timing of the sound wave to each sound wave
receiving element 6 The device can be obtained.
[0050]
In a sound wave receiving element capable of detecting the incident direction of such sound
waves, high accuracy is particularly required for the pitch between the sound wave receiving
portions 6a of the respective sound wave receiving elements 6, and the sound wave receiving
element 6 is mounted with high position accuracy. Although it becomes important, since the
cover 3 of the present embodiment is a three-dimensional circuit forming substrate as described
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above, these sound wave introducing holes 5 can be provided at a high accuracy pitch by
injection molding. Therefore, the sound wave receiving portion 6a of the sound wave receiving
element 6 can be mounted on the cover 3 with a high precision pitch, and this makes it possible
to arrange the sound wave receiving device 1 on which the sound wave receiving element 6 is
mounted in an array. The manufacturing process is simplified, and the sound wave receiving
units 6a can be arranged at a higher pitch.
[0051]
In addition, as shown in FIG. 9 (b), the acoustic wave receiving elements 6 are formed in an array,
and nine acoustic wave receiving portions 6a are arranged in an array of 3 rows and 3 columns
at a predetermined pitch. By mounting the acoustic wave receiving element 6 on the cover 3
provided with the above-mentioned acoustic wave introducing holes 5 in an array, the acoustic
wave receiving portions 6a can be arranged at a still higher pitch, and identification of the
incident direction of the acoustic wave Can be performed with high accuracy.
[0052]
In FIG. 9, the sound wave introduction holes 5 and the sound wave receiving parts 6a are
arranged in an array of 3 rows and 3 columns, but the arrangement is not limited to 3 rows and
3 columns, and a suitable arrangement is selected according to the application. Can be used.
[0053]
(A) is a schematic sectional drawing of the sound wave receiving apparatus of Embodiment 1 of
this invention, (b) is the schematic sectional drawing which abbreviate | omitted a part of sound
wave receiving apparatus same as the above.
(A) is a cross-sectional view showing a piezoelectric sensor, and (b) is a cross-sectional view
showing a condenser microphone.
(A) is a schematic sectional drawing of the other sound wave receiving apparatus same as the
above, (b) is a bottom view of the sound wave receiving apparatus same as the same. (A) is the
schematic sectional drawing which abbreviate | omitted a part of other sound wave receiving
apparatuses of the same as the above, and (b) is the schematic sectional drawing which
abbreviate | omitted a part of other sound wave receiving apparatuses same as the above. (A) is a
schematic sectional drawing of the sound wave receiving apparatus of Embodiment 2 of this
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invention, (b) is a schematic sectional drawing of the other sound wave receiving apparatus same
as the above. (A) is sectional drawing which shows an example of an acoustic wave receiving
element and a cover same as the above, (b) is a schematic sectional drawing which shows the
further another acoustic wave receiving apparatus same as the above. (A) is a schematic
explanatory drawing which shows an example of a taper-shaped sound wave introduction hole,
(b) is a schematic explanatory drawing which shows a suitable example of a taper-shaped sound
wave introduction hole, (c) is a taper It is a schematic explanatory drawing which shows the
other example of the sound wave introduction hole of shape, (d) is a schematic explanatory
drawing which shows the further another example of a sound wave introduction hole of taper
shape. (A) is a schematic explanatory drawing which shows an example of the shape of a sound
wave introduction hole, (b) is a schematic explanatory drawing which shows the other example of
the shape of a sound wave introduction hole, (c) is a sound wave introduction hole FIG. 10 is a
schematic explanatory view showing still another example of the shape of (b), and (d) is a
schematic explanatory view showing another example of the shape of the sound wave
introduction hole. (A) is a perspective view of the cover provided with the sound wave
introduction holes in an array, and (b) is a schematic explanatory view showing the cover
provided with the sound wave introduction holes in an array and the arrayed sound wave
receiving elements It is.
Explanation of sign
[0054]
DESCRIPTION OF SYMBOLS 1 sound wave receiving apparatus 2 apparatus main body 3 cover 4
base 4a bottom part 4b side wall part 5 sound wave introduction hole 5a opening surface 6
sound wave receiving element 6a sound wave receiving part 7a, 7b wire 8 1st electrode plate 8a
output terminal 9 2nd electrode plate 9a Output Terminal 10 Ferroelectric Thin Film 11 Support
Substrate 11a Diaphragm 11b Main Surface 12 Shield Pattern
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