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JP2013058889

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DESCRIPTION JP2013058889
Abstract: The present invention provides an electroacoustic transducer, an arrayed
electroacoustic transducer, and an electroacoustic transducer system that can be manufactured
without complicating the process. An electro-acoustic transducer has a first spacer, a second
spacer, a diaphragm whose outer peripheral portion is supported by the first spacer and the
second spacer, and a main surface opposite to the diaphragm. A first base on which a first
electrode is formed at least in part, and a second base on which a second electrode is formed on
at least a part of the main surface facing the diaphragm. The surface of the first substrate facing
the diaphragm is more convex than the surface of the first electrode with respect to the
diaphragm, and the surface of the second substrate facing the diaphragm is the second electrode
of the second substrate. The surface is more convex to the diaphragm than the surface. [Selected
figure] Figure 1
Electro-acoustic transducer, array-like electro-acoustic transducer and electro-acoustic
transducer system
[0001]
The present disclosure relates to an electroacoustic transducer, an array of electroacoustic
transducer, and an electroacoustic transducer system. In particular, the present disclosure relates
to an electro-acoustic transducer and an array-like electro-acoustic transducer device and an
electro-acoustic transducer system that generate vibrations with a digital signal as an input and
reproduce sound and the like.
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[0002]
Development of a digital speaker that reproduces voice, music and the like using data recorded
by a digital method as an input is in progress.
[0003]
The digital speaker is configured, for example, as a group of a plurality of electroacoustic
transducers.
Unlike an analog speaker that receives an analog signal corresponding to an amplitude change of
an audio signal and reproduces voice, music, etc., in a digital speaker, each electroacoustic
transducer carries out electroacoustic conversion corresponding to a bit of an input signal. I do.
[0004]
The sounds generated by the individual electroacoustic transducers are spatially synthesized so
that the digitally recorded data is perceived by us as speech and music. The sound generated by
each of the electroacoustic transducers is, for example, a pulse sound, and the digital speaker has
a feature of consuming less power.
[0005]
As a digital speaker, a digital speaker configured as a microelectromechanical system (MEMS)
obtained by application of semiconductor manufacturing technology or miniaturization of
mechatronics technology is generally known. For example, Patent Document 1 below discloses a
digital speaker module that generates an acoustic output in response to an unary digital drive
signal. For example, Patent Document 2 below discloses an audio electroacoustic transducer
system integrated with a substrate on which an encoder or a decoder is formed. In addition, for
example, Patent Document 3 below discloses a driving method and a driving device relating to a
plurality of arranged conversion elements.
[0006]
Patent Document 1: JP-A-2001-016675 Patent Document 2: JP-A-2008-510378 Patent
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Document 2: International Publication 2009/066290
[0007]
However, if it is going to manufacture a digital speaker as what is called MEMS, the management
of a process will be complicated and the huge period and expense will be needed for digital
speaker development.
[0008]
There is a need for digital speakers that can be manufactured without complicating the process.
[0009]
According to a first preferred embodiment of the present disclosure, an electroacoustic
transducer comprises a first spacer, a second spacer, a diaphragm, a first substrate, and a second
substrate.
The diaphragm is supported at its outer periphery by the first spacer and the second spacer.
A first electrode is formed on at least a part of the main surface of the first substrate facing the
diaphragm.
A second electrode is formed on at least a part of the main surface of the second base opposite to
the diaphragm. The surface of the first base material facing the diaphragm is more convex to the
diaphragm than the surface of the first electrode. The surface of the second base material facing
the diaphragm is more convex to the diaphragm than the surface of the second electrode.
[0010]
In a second preferred embodiment of the present disclosure, an arrayed electroacoustic
transducer comprises a first spacer, a second spacer, a diaphragm, a first substrate, and a second
substrate. . In the diaphragm, the plurality of openings formed in the first spacer and the
plurality of regions corresponding to the plurality of openings formed in the second spacer are
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3
independently vibrated, respectively. Supported by the second spacer and the second spacer. An
electrode is formed on each of a plurality of regions corresponding to the plurality of openings
formed in the first spacer on the main surface of the first base opposite to the diaphragm. An
electrode is formed on each of a plurality of regions corresponding to the plurality of openings
formed in the second spacer on the main surface of the second base material facing the
diaphragm. The array-shaped electro-acoustic transducer includes a plurality of electro-acoustic
transducers, each of which is a unit of each of the vibration-free regions in the diaphragm.
[0011]
According to a third preferred embodiment of the present disclosure, the electroacoustic
transducing system comprises: a first spacer, a second spacer, a diaphragm, a first substrate, a
second substrate, and one or more. A top side driver circuit and one or more bottom side driver
circuits are provided. In the diaphragm, the plurality of openings formed in the first spacer and
the plurality of regions corresponding to the plurality of openings formed in the second spacer
are independently vibrated, respectively. Supported by the second spacer and the second spacer.
An electrode is formed on each of a plurality of regions corresponding to the plurality of
openings formed in the first spacer on the main surface of the first base opposite to the
diaphragm. An electrode is formed on each of a plurality of regions corresponding to the
plurality of openings formed in the second spacer on the main surface of the second base
material facing the diaphragm. Among the main surfaces of the first base material, one or more
upper surface side driver circuits are disposed on the main surface opposite to the main surface
facing the diaphragm, and a plurality of the upper surface driver circuits are formed on the first
base material. Electrical connection with the electrodes of the Among the main surfaces of the
second base material, one or more bottom side driver circuits are disposed on the main surface
opposite to the main surface facing the diaphragm, and a plurality of them are formed on the
second base material. Electrical connection with the electrodes of the The electro-acoustic
conversion system is independently operated in response to drive signals from one or more of
the top side driver circuits or one or more of the bottom side driver circuits, with each of the
regions made independently vibrateable in the diaphragm as a unit. A plurality of electroacoustic
transducers to be driven are provided.
[0012]
In the present disclosure, both surfaces of the diaphragm are supported by a first spacer
provided with a plurality of openings and a second spacer provided with a plurality of openings.
A first substrate and a second substrate are respectively disposed outside the first spacer and the
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second spacer. A plurality of electrodes are disposed on the main surface of the first base
material facing the diaphragm, corresponding to the plurality of openings provided in the first
spacer. A plurality of electrodes are arranged on the main surface of the second base material
facing the diaphragm, corresponding to the plurality of openings provided in the second spacer.
[0013]
An electrode disposed on the first substrate, a first spacer, and one of regions in the diaphragm
corresponding to the plurality of openings provided in the first spacer and the second spacer; A
second spacer and an electrode disposed on the second substrate constitute one unit of the
electroacoustic transducer. That is, one of the regions in the diaphragm corresponding to the
plurality of openings provided in the first spacer and the second spacer functions as a diaphragm
in one unit of the electroacoustic transducer. The vibrations of the individual diaphragms are
independent of one another.
[0014]
The surface of the first base opposite to the diaphragm is convex with respect to the diaphragm
than the surface of the first electrode, and the surface of the second base opposite to the
diaphragm is the second electrode of the second base. The surface is more convex to the
diaphragm than the surface. Therefore, the contact between the diaphragm portion and the
electrode disposed on the first base and the electrode disposed on the second base is prevented.
The thickness of the first spacer and the second spacer controls the amplitude of the diaphragm
portion and suppresses variation in the maximum displacement of the diaphragm portion
between the electroacoustic transducers.
[0015]
A plurality of diaphragms are configured by dividing one diaphragm by a plurality of openings
provided in the first spacer and the second spacer. Thus, the arrayed electroacoustic transducing
devices and electroacoustic transducing systems of the present disclosure comprise an array of a
plurality of independently driven electroacoustic transducers.
[0016]
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In the present disclosure, it is not necessary to manufacture an electroacoustic transducer as a
so-called MEMS. In addition, since a plurality of diaphragms are formed with the diaphragm in
common, the manufacturing process of the electroacoustic transducer, the arrayed
electroacoustic transducer, and the electroacoustic transducer system does not become
complicated.
[0017]
According to at least one embodiment, an electro-acoustic transducer, an array of electroacoustic transducers, and an electro-acoustic transducer system that can be manufactured
without complicating the process can be provided.
[0018]
FIG. 1A is a plan view showing a configuration example of the electroacoustic transducer system
according to the first embodiment.
FIG. 1B is a side view of the electro-acoustic transducer system shown in FIG. 1A. FIG. 2 is an
exploded perspective view of the electro-acoustic conversion system shown in FIGS. 1A and 1B.
FIG. 3A is an enlarged view of a portion P1 in FIG. FIG. 3B is an enlarged view of a portion
corresponding to the portion P1 shown in FIG. 2 on the surface of the upper base material facing
the upper spacer. FIG. 3C is an enlarged view of one of the plurality of electrodes in FIG. 3B and
the periphery thereof. FIG. 4A is an enlarged view of a portion P2 in FIG. FIG. 4B is an enlarged
view of a portion P3 in FIG. FIG. 4C is an enlarged view of one of the plurality of diaphragms in
FIG. 4B and the periphery thereof. FIG. 5A is a schematic view of the electro-acoustic conversion
system according to the first embodiment as viewed from the upper substrate side. FIG. 5B is a
schematic diagram showing one unit of the electroacoustic transducer in the electroacoustic
transducer system and the arrayed electroacoustic transducer. FIG. 6A is a schematic view
showing a VIxz-VIxz cross section of FIG. 5B. FIG. 6B is a schematic view showing a VIyz-VIyz
cross section of FIG. 5B. FIG. 7A is an XZ sectional view showing another configuration example
of the electroacoustic transducer. FIG. 7B is a YZ sectional view showing another configuration
example of the electroacoustic transducer. FIG. 8 is a block diagram showing an example of a
specific configuration of a signal processing unit and an electro-acoustic conversion system
according to an embodiment of the present disclosure. FIG. 9A is a plan view showing a
configuration example of the electroacoustic transducer system according to the second
embodiment. FIG. 9B is a side view of the electro-acoustic transducer system shown in FIG. 9A.
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FIG. 10 is an exploded perspective view of the electro-acoustic transducer system shown in FIGS.
9A and 9B. 11A is an enlarged view of a portion Q1 in FIG. 11B is an enlarged view of a portion
U shown in FIG. 11A. FIG. 11C is an enlarged view of a portion corresponding to the U portion
shown in FIG. 11A in the surface of the upper base material facing the upper spacer. FIG. 12A is
an enlarged view of a portion Q2 in FIG. FIG. 12B is a schematic view showing a cross section of
one configuration example of the vibrating member. FIG. 13A is a schematic view of the electroacoustic transducer system according to the second embodiment as viewed from the upper
substrate side. FIG. 13B is a schematic diagram showing one unit of the electroacoustic
transducer in the electroacoustic transducer system and the arrayed electroacoustic transducer.
FIG. 14A is a schematic view showing the XIV-XIV cross section of FIG. 13B. FIG. 14B is an XZ
cross-sectional view showing another configuration example of the electroacoustic transducer.
[0019]
Hereinafter, embodiments of the electroacoustic transducer, the arrayed electroacoustic
transducer, and the electroacoustic transducer system will be described. The description will be
made in the following order. ??? First embodiment> [Schematic configuration of electroacoustic conversion system] (upper substrate) (upper spacer) (vibration member) (driver circuit)
[schematic configuration of array-like electro-acoustic transducer] [electro-acoustic transducer
Schematic Configuration of [Outline of Operation of Electroacoustic Transducer System] <2.
Second embodiment> [Schematic configuration of electro-acoustic conversion system] (upper
substrate) (upper spacer) (vibration member) [schematic configuration of array-like electroacoustic transducer] [schematic configuration of electro-acoustic transducer ] <3. Modified
example>
[0020]
The embodiments described below are preferred specific examples of the electroacoustic
transducer, the array-like electroacoustic transducer, and the electroacoustic transducer system.
In the following description, although various technically preferable limitations are attached,
unless specified to limit the present disclosure, an electroacoustic transducer, an array-like
electroacoustic transducer, and an electroacoustic transducing system are described. The
examples are not limited to the embodiments shown below.
[0021]
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7
??? First embodiment> [Schematic configuration of electro-acoustic conversion system] FIG.
1A is a plan view showing a configuration example of an electro-acoustic conversion system
according to a first embodiment. FIG. 1B is a side view of the electro-acoustic transducer system
shown in FIG. 1A. FIG. 2 is an exploded perspective view of the electro-acoustic conversion
system shown in FIGS. 1A and 1B.
[0022]
As shown in FIG. 1B and FIG. 2, the electroacoustic conversion system 1 according to the first
embodiment roughly includes an upper base 7 t, an upper spacer 5 t, a vibrating member 3, a
lower spacer 5 b and a lower base. It has a configuration in which the materials 7b are stacked in
order. As shown in FIGS. 1A and 1B and FIG. 2, for example, four driver circuits 9 at, 9 bt, 9 ct
and 9 dt are disposed on the upper base 7 t. A wiring pattern 8Wt is formed, for example, on the
main surface exposed to the outside among the main surfaces of the upper side base material 7t.
The wiring pattern is, for example, a collection of electrode parts and wiring parts. In addition,
the lower side base material 7b also has the structure similar to the structural example of the
upper side base material 7t shown to FIG. 1A. For example, in the lower base 7b, for example,
four driver circuits 9ab, 9bb, 9cb and 9db are disposed, and among the main faces of the lower
base 7b, for example, wiring on the main surface exposed to the outside A pattern 8Wb is
formed.
[0023]
The electroacoustic transducer system 1 has a plurality of electroacoustic transducers. Individual
electro-acoustic transducers are constituted by members arranged on the upper and lower sides
of the diaphragm portion and the diaphragm portion with a part of the vibrating member 3 as a
diaphragm portion. As will be described later, in the configuration example shown in FIG. 2, one
of the plurality of electrodes formed on the upper base 7t, the upper spacer, the diaphragm, the
lower spacer, and the lower base One unit of the electroacoustic transducer is formed of one of
the plurality of electrodes formed on 7b.
[0024]
The plurality of electroacoustic transducers are arranged, for example, in correspondence with
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the grid points to constitute an array of electroacoustic transducers. Each of the plurality of
electrodes formed on the upper side substrate 7t and the driver circuits 9at, 9bt, 9ct and 9dt
arranged on the upper side substrate are electrically driven by the wiring pattern 8Wt formed on
the upper side substrate 7t. Connected Similarly, each of the plurality of electrodes formed on the
lower base 7b and the driver circuits 9ab, 9bb, 9cb and 9db disposed on the lower base 7b are
formed on the lower base 7b. It is electrically connected by the wiring pattern 8Wb. Thus, the
individual electroacoustic transducers are driven by driver circuits disposed on the upper
substrate 7t and the lower substrate 7b.
[0025]
Next, referring to FIGS. 2 to 4, the upper base 7 t and the lower base 7 b, the upper spacer 5 t
and the lower spacer 5 b, the vibrating member 3 and the driver circuits 9 at, 9 bt, 9 ct and 9 dt
will be sequentially described. Do. The electroacoustic conversion system 1 has a substantially
symmetrical configuration with respect to the vibrating member 3. Therefore, the lower base 7b
and the lower spacer 5b are disposed symmetrically to the upper base 7t and the upper spacer 5t
with respect to the vibrating member 3. Furthermore, the configuration of the lower base 7b is
substantially the same as the configuration of the upper base 7t, and the configuration of the
lower spacer 5b is substantially the same as the configuration of the upper spacer 5t. Therefore,
in the following description, the specific description of the configuration of the lower base 7b, the
specific description of the configuration of the lower spacer 5b, and the driver circuits 9ab, 9bb,
9cb arranged on the lower base 7b. The specific description of 9 db is omitted.
[0026]
(Upper Base Material) The upper base material 7t has a function as a support of the vibrating
member 3, and constitutes the outer shape of the electroacoustic transducer system 1. Although
FIG. 1A, FIG. 1B, and FIG. 2 showed the structural example by which the shape of the upper side
base material 7t was made flat form, it is not restricted to this. The outer shape of the upper base
7t is not limited to a square.
[0027]
FIG. 3A is an enlarged view of a portion P1 in FIG. In the following, when it is necessary to
identify individual electroacoustic transducers or members corresponding to individual
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electroacoustic transducers, these will be appropriately identified by subscripts.
[0028]
As shown in FIG. 3A, for example, a plurality of electrode portions and a plurality of wiring
portions are formed on the main surface of the upper side base material. A wiring pattern 8Wt is
configured by the plurality of electrode portions and the plurality of wiring portions formed on
the upper side base material.
[0029]
In FIG. 3A, a U portion surrounded by a broken line corresponds to one unit of the plurality of
electroacoustic transducers. Each electrode portion 8eti is formed corresponding to one of the
plurality of electroacoustic transducers, and each electrode portion 8eti is electrically connected
to a driver circuit described later by an individual wiring portion 8wti. Connected to
[0030]
For example, two through holes ht1i and ht2i are formed in each of the electrode portions 8eti.
The through holes ht1i and ht2i are air holes formed to allow air to enter and exit with the
vibration of the vibrating member 3 described later. Although FIG. 3A shows an example in which
two circular through holes ht1i and ht2i are formed in each of the electrode parts 8eti, the
number, position, shape, size and the like of the through holes are not limited to this.
[0031]
FIG. 3B is an enlarged view of a portion corresponding to the portion P1 shown in FIG. 2 on the
surface of the upper base material facing the upper spacer. In FIG. 3B, a U portion surrounded by
a broken line corresponds to one unit of the plurality of electroacoustic transducers. Note that
FIG. 3B is an enlarged view of one main surface of the upper side base material, but since the
configuration of the lower side base material 7b is substantially the same as the configuration of
the upper side base material 7t, FIG. It corresponds to the figure which expands and shows P5
part shown to.
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10
[0032]
As shown in FIG. 3B, a plurality of main surfaces of the upper side base material 7t
corresponding to one of the plurality of electroacoustic transducers are also provided on the
main surface on the side facing the vibrating member 3 The electrodes are formed. Among the
main surfaces of the upper side base material 7t, the electrode 6eti formed on the main surface
facing the vibrating member 3 is electrically connected to the electrode portion 8eti formed on
the main surface opposite to the main surface. It is connected to the. Therefore, a driving voltage
from a driver circuit described later is applied to the electrode 6eti formed on the main surface
on the side facing the vibrating member 3 via the electrode portion 8eti and the wiring portion
8wti.
[0033]
FIG. 3C is an enlarged view of one of the plurality of electrodes in FIG. 3B and the periphery
thereof. In FIG. 3C, regions other than the electrode 6eti and the through holes ht1i and ht2i are
shown by hatching.
[0034]
As shown in FIG. 3C, the electrode 6 eti is, for example, in a shape (so-called dumbbell shape) in
which two places of the circumference are directed to the center. The surface of the electrode 6
eti is recessed with respect to the surface of the upper base 7 t facing the vibrating member 3.
That is, the dumbbell-shaped narrowed portions CP1i and CP2i protrude toward the vibrating
member 3. The dumbbell-shaped narrowed portions CP1i and CP2i function as stoppers for
preventing the contact between the vibrating member 3 and the electrode 6eti as described later.
[0035]
From the viewpoint of increasing the driving force with respect to the vibrating member 3 as
much as possible, it is preferable that the area of the electrode 6eti formed on the main surface
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11
facing the vibrating member 3 be large. On the other hand, from the viewpoint of increasing the
area in which wiring can be performed, it is preferable that the area of the electrode portion 8eti
formed on the main surface on the side not facing the vibrating member 3 be small. Therefore, in
FIGS. 3A to 3C, the shape of the electrode 6eti formed on the main surface facing the vibrating
member 3 and the shape of the electrode portion 8eti formed on the main surface opposite to the
main surface Although the example which is not identical is shown, the shapes of the electrode
6eti and the electrode portion 8eti are not limited to this.
[0036]
As a material which constitutes upper substrate 7t, for example, low temperature co-fired
ceramics called LTCC (Low Temperature Co-fired Ceramics) can be used. LTCC is a ceramic
material obtained by adding a glass-based material to aluminum oxide and firing it at a
temperature of about 900 ░ C. or less. The firing temperature of LTCC is lower at around 900 ░
C or less compared to the case where no glass-based material is added, so it is also possible to
fire a substrate on which a wiring pattern using copper or silver with low conductor resistance is
formed. is there. Therefore, for example, the laminated base material including the substrate on
which the wiring pattern is formed may be fired to form the laminated base material having the
wiring pattern formed therein as the upper base material 7t.
[0037]
For example, a circuit molded part called MID (Molded Interconnect Device) may be used as the
upper base 7t. The MID is a circuit molded part in which an electric circuit is formed on a resin
structure, and since the electric circuit can be formed only by plating or vapor deposition, it has
the feature of being environmentally friendly. By applying the MID to the upper side base
material 7t, it becomes easy to make the upper side base material 7t a base material on which a
level difference is formed.
[0038]
As a material which constitutes upper substrate 7t, it is not restricted to this, for example, resin
material, glass, etc. may be used. Of course, the material forming the upper base 7t and the
material forming the lower base 7b may not be the same.
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[0039]
As a material which comprises electrode part 8eti, wiring part 8wti, and electrode 6eti, the
material with small conductor resistance is preferable, for example, although copper, gold, silver,
aluminum, nickel, or these combination etc. can be mentioned, It is not limited. From the
viewpoint of preventing the manufacturing process from being complicated, it is preferable that
the electrode portion 8eti, the wiring portion 8wti and the electrode 6eti be made of the same
material. The electrode portion 8eti, the wiring portion 8wti and the electrode 6eti can be formed
by, for example, plating, vapor deposition, sputtering or the like.
[0040]
(Upper Spacer) FIG. 4A is an enlarged view of a portion P2 in FIG. 4A is an enlarged view of one
main surface of the upper spacer 5t, but since the configuration of the lower spacer 5b is
substantially the same as the configuration of the upper spacer 5t, FIG. 4A corresponds to the
portion P4 in FIG. This corresponds to the enlarged view.
[0041]
As shown in FIG. 4A, in the upper spacer 5t, a plurality of openings Hti are formed corresponding
to one of the plurality of electroacoustic transducers. In FIG. 4A, regions other than the opening
Hti are shown by hatching.
[0042]
The upper spacer 5t is a member for securing displacement in a direction toward the upper base
7t in the vibrating member 3 described later. Therefore, the area of the individual openings Hti is
larger than the area of the individual electrodes 6eti. When a circle including the electrode 6eti is
assumed, the diameter of the circle is, for example, several mm, while the diameter of the
opening Hti is larger than the diameter of the circle.
[0043]
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As a material which comprises the upper side spacer 5t, the material excellent in electrical
insulation is preferable, for example, although resin material, glass, rubber etc. can be mentioned,
it is not restricted to these.
[0044]
(Vibrating Member) FIG. 4B is an enlarged view of a portion P3 in FIG.
The vibrating member 3 is a vibrating plate for generating air vibration in electroacoustic
conversion.
[0045]
As shown in FIG. 4B, a plurality of diaphragm portions Di are arranged in the vibrating member
3. The diaphragm portion Di is disposed at a position corresponding to the plurality of openings
Hti provided in the upper spacer 5t. Therefore, each diaphragm part Di is independently made
freely vibrating along the direction (Z-axis direction) perpendicular to the paper surface.
[0046]
In the present disclosure, the diaphragm portions Di of individual electroacoustic transducers are
arranged on a common member. Therefore, according to the present disclosure, an
electroacoustic transducer and an array of electroacoustic transducer and an electroacoustic
transducer system can be manufactured without complicating the process.
[0047]
As a material which comprises the vibration member 3, the material with small conductor
resistance is preferable, for example, a metal material can be mentioned. Examples of the metal
material include stainless steel, titanium, aluminum, beryllium, magnesium, titanium boride,
duralumin and the like. Stainless steel is an alloy in which iron contains chromium and nickel.
The stainless steel can be appropriately selected from austenitic stainless steel or ferritic
04-05-2019
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stainless steel or martensitic stainless steel. For example, in accordance with JIS standard
notation, SUS304, SUS304L, SUS316, SUS310S, SUS309S, SUS303, and SUS301. SUS430,
SUS440C, SUS420J2, and SUS410S are suitable.
[0048]
FIG. 4C is an enlarged view of one of the plurality of diaphragms in FIG. 4B and the periphery
thereof. When a metal material such as stainless steel is used as the material constituting the
vibrating member 3, for example, the shapes Di of the individual diaphragms tend to vibrate in
order to make the displacement of the individual diaphragms Di as large as possible. It is
preferred that it be shaped. Specifically, for example, as shown in FIG. 4C, it is preferable that
slits be provided in the outer peripheral portion of each diaphragm portion Di.
[0049]
In the configuration example shown in FIG. 4C, four slits s1i, s2i, s3i and s4i are formed in the
outer peripheral part of each diaphragm part. That is, the central part of the diaphragm part Di
shown in FIG. 4C is supported by the four arms h1i, h2i, h3i and h4i. In addition, in FIG. 4B and
FIG. 4C, area | regions other than a slit were shown by meshing.
[0050]
Since the four arms h1i, h2i, h3i and h4i function as cantilevers, the displacement of the central
portion of the diaphragm Di can be increased compared to the case where the slit is not formed.
Although FIG. 4C shows an example in which four slits s1i, s2i, s3i and s4i are formed on the
outer peripheral portion of each diaphragm portion Di, the number, position, shape, size and the
like of the slits are set to this. It is not limited.
[0051]
(Driver Circuit) The driver circuit is a circuit that supplies a current for driving each of the
electroacoustic transducers, and is formed of, for example, a combination of transistors. As
shown in FIGS. 1A and 1B and FIG. 2, for example, four driver circuits 9 at, 9 bt, 9 ct and 9 dt are
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disposed on the upper base 7 t. The electrode 6eti formed on the upper base 7t has an electrical
connection with any of the driver circuits 9at, 9bt, 9ct and 9dt disposed on the upper base 7t.
Similarly, for example, four driver circuits 9ab, 9bb, 9cb and 9db are disposed on the lower base
7b. Each of the plurality of electrodes formed on the lower side substrate 7b has electrical
connection with any of the driver circuits 9ab, 9bb, 9cb and 9db arranged on the lower side
substrate 7b.
[0052]
For example, when the vibrating member 3 is set to the ground potential, the electrode 6eti
corresponding to one electroacoustic transducer out of the plurality of electrodes formed on the
upper base 7t is set to a high potential, the electroacoustic transducer The electrostatic force acts
on the diaphragm portion Di of the first and second diaphragm portions Di, and the diaphragm
portion Di approaches the upper base 7t. That is, the displacement in the + Z direction of the
diaphragm portion Di of one electroacoustic transducer is controlled by the driver circuit
disposed on the upper base 7t. At this time, among the plurality of electrodes formed on the
lower side substrate 7b, the electrode corresponding to the electroacoustic transducer is set to
the ground potential.
[0053]
Similarly, the displacement of the diaphragm part Di of one electroacoustic transducer in the -Z
direction is controlled by a driver circuit disposed on the lower substrate 7b. Thus, the individual
electroacoustic transducers are driven by driver circuits disposed on the upper substrate 7t and
the lower substrate 7b.
[0054]
The driver circuit supplies a drive current for bringing the diaphragm portion of the
electroacoustic transducer closer to the upper substrate or the lower substrate according to the
input signal, as described later. The manufacturer of the electro-acoustic conversion system 1
can appropriately set which one of the plurality of electro-acoustic transducers is to be driven.
[0055]
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[Schematic Configuration of Arrayed Electroacoustic Transducer] FIG. 5A is a schematic view of
the electroacoustic transducer system according to the first embodiment as viewed from the
upper substrate side. 5A is a view showing one principal surface of the upper base 7t, but since
the configuration of the lower base 7b is substantially the same as the configuration of the upper
base 7t, FIG. It corresponds also to the schematic seen from the lower side base material 7b side.
[0056]
As shown in FIG. 5A, a plurality of electro-acoustic transducers are arranged, for example, in
correspondence with lattice points to constitute an array-like electro-acoustic transducer 11. The
number of the plurality of electroacoustic transducers in the arrayed electroacoustic transducer
11 can be set arbitrarily. Specifically, the number of electroacoustic transducers in the array-like
electroacoustic transducer 11 can be, for example, one less than the power of 2 or 2 of the
power. By setting the number of the plurality of electroacoustic transducers to a power of 2, for
example, it is possible to prevent the circuit for generating drive signals for the plurality of
electroacoustic transducers from being complicated.
[0057]
The arrangement of the plurality of electroacoustic transducers can also be set arbitrarily. For
example, a plurality of electroacoustic transducers can be arranged radially, concentrically,
polygonally, elliptically or the like.
[0058]
The outer shape of the arrayed electroacoustic transducer 11 can also be set arbitrarily. For
example, when the outer shape of the upper base 7t is rectangular, for example, the driver
circuits 9at, 9bt, 9ct and 9dt are disposed one by one on four sides of the square. At this time, it
is also possible to divide a plurality of electroacoustic transducers into a plurality of groups and
associate the plurality of electroacoustic transducers belonging to each group with each of the
driver circuits 9at, 9bt, 9ct and 9dt. is there.
04-05-2019
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[0059]
For example, in FIG. 5A, the plurality of electroacoustic transducers are divided into four groups
Ga, Gb, Gc and Gd, and the plurality of electroacoustic transducers belonging to the first group Ga
and the driver circuit 9 at The structural example connected by the wiring pattern 8 Watt is
shown. In FIG. 5A, the plurality of electroacoustic transducers belonging to the second group Gb
are indicated by circles represented by broken lines, and the plurality of electroacoustic
transducers belonging to the third group Gc are indicated by black circles. , And a plurality of
electroacoustic transducers belonging to the fourth group Gd are indicated by shaded circles. For
example, the plurality of electro-acoustic transducers belonging to the second group Gb are
connected with the driver circuit 9bt, and the plurality of electro-acoustic transducers belonging
to the third group Gc are connected with the driver circuit 9ct, The plurality of electroacoustic
transducers belonging to the fourth group Gd are connected to the driver circuit 9dt.
[0060]
As described above, by dividing the plurality of electroacoustic transducers into a plurality of
groups and arranging a plurality of driver circuits corresponding to each group, it is possible to
prevent the wiring pattern from becoming complicated. In FIG. 5A, although the plurality of
electroacoustic transducers are divided into a plurality of groups along a rectangular diagonal,
the present invention is not limited to this example. The number and arrangement of driver
circuits can also be appropriately set in accordance with the number and arrangement of a
plurality of electroacoustic transducers.
[0061]
[Schematic Configuration of Electro-Acoustic Transducer] FIG. 5B is a schematic diagram
showing one unit of the electro-acoustic transducer in the electro-acoustic transducer system and
the array-like electro-acoustic transducer. Specifically, the electroacoustic transducer Ti is one of
a plurality of electrodes formed on the upper base 7t, the upper spacer portion Sti, the
diaphragm portion Di, the lower spacer portion Sbi, and the lower side. It comprises one of a
plurality of electrodes formed on the base 7b. In FIG. 5B, among the main surfaces of the upper
base 7t, the electrode portion 8eti formed on the main surface not facing the vibrating member 3
and the main surface of the upper base 7t are opposed to the vibrating member 3. It shows a
state in which the electrode 6eti formed on the main surface on the side, the upper spacer
portion Sti, and the diaphragm portion Di are superimposed. In FIG. 5B, of the main surfaces of
04-05-2019
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the lower base 7b, the electrode 8ebi formed on the main surface not facing the vibrating
member 3 and the main surface of the lower base 7b are opposed to the vibrating member 3.
The illustration of the electrode 6ebi and the lower spacer portion Sbi formed on the main
surface on the side of the upper side is omitted. Further, in FIG. 5B, the region other than the
opening Hti of the upper spacer portion Sti is shown by hatching.
[0062]
FIG. 6A is a schematic view showing a VIxz-VIxz cross section of FIG. 5B. FIG. 6B is a schematic
view showing a VIyz-VIyz cross section of FIG. 5B. As shown to FIG. 6A and FIG. 6B, the
diaphragm part Di which is a part of vibration member 3 is lower spacer part Sbi which is a part
of upper spacer part Sti which is a part of upper spacer 5t, and lower spacer 5b. The outer
peripheral portion is supported by the
[0063]
An upper base 7t and a lower base are provided by applying a drive voltage according to an
input audio signal to the electrode 6eti formed on the upper base 7t or the electrode 6ebi formed
on the lower base 7b. The diaphragm portion Di is displaced between the members 7b. A driving
voltage from a driver circuit is applied to the electrode 6ebi via the electrode portion 8ebi and
the wiring portion 8wbi. In addition, since the outer peripheral part of the diaphragm part Di is
supported by the upper side spacer part Sti and the lower side spacer Sbi, the displacement of
the diaphragm part Di in each electroacoustic transducer Ti is each independent.
[0064]
The thickness of the upper spacer portion Sti and the lower spacer portion Sbi is, for example,
about several ?m. By adjusting the thickness of the upper spacer 5t and the lower spacer 5b, the
amplitude of the diaphragm portion Di can be easily managed. The thickness of the diaphragm
portion Di is, for example, about several ?m.
[0065]
04-05-2019
19
The displacement of the diaphragm portion Di generates air vibration. The vibration of air
accompanying the displacement of the diaphragm part Di is made through the two through holes
ht1i and ht2i formed in the electrode part 8eti and the electrode 6eti and the two through holes
hb1i and hb2i formed in the electrode part 8ebi and the electrode 6ebi It is transmitted to the
outside. By transmitting the vibration of air accompanying the displacement of the diaphragm
portion Di to the outside, electroacoustic conversion is performed in each of the electroacoustic
transducers Ti. The diameters of the individual through holes ht1i, ht2i, hb1i and hb2i are, for
example, several mm or less.
[0066]
As shown in FIG. 6A, in the upper substrate, portions PR1i and PR2i corresponding to the
dumbbell shaped waisted portions CP1i and CP2i shown in FIG. 3C protrude toward the central
portion of the electroacoustic transducer Ti. In addition, the surface of the upper base 7t facing
the diaphragm portion Di is convex with respect to the surface of the electrode 6eti. The
thickness of the upper base 7t is, for example, about several tens of ?m, and for example, a gap
of about 1 ?m to 100 ?m between the surface of the upper base 7t facing the diaphragm
portion Di and the surface of the electrode 6eti Is formed. That is, gp shown in FIG. 6B is about 1
?m to 100 ?m. Similarly, the surface of the lower base 7b opposite to the diaphragm portion Di
is convex with respect to the surface of the electrode 6ebi.
[0067]
The surface of the upper base 7t facing the diaphragm portion Di is convex with respect to the
surface of the electrode 6eti formed on the upper base 7t, and hence the electrode formed on the
diaphragm Di and the upper base 7t Contact with 6eti is prevented. Similarly, since the surface of
the lower base 7b opposite to the diaphragm Di is convex with respect to the surface of the
electrode 6ebi formed on the lower base 7b, the diaphragm Di and the lower base The contact
with the electrode 6ebi formed on 7b is prevented.
[0068]
FIG. 7A is an XZ sectional view showing another configuration example of the electroacoustic
transducer. FIG. 7B is a YZ sectional view showing another configuration example of the
electroacoustic transducer. FIG. 7A is a diagram corresponding to FIG. 6A, and FIG. 7B is a
04-05-2019
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diagram corresponding to FIG. 6B.
[0069]
As shown in FIGS. 7A and 7B, the upper base or lower base of the electroacoustic transducer T2i
may be configured as a laminated base. 7A and 7B, an example in which the upper base 27t is
formed as a laminated base of the base 27ta and the base 27tb, and the lower base 27b is
formed as a laminated base of the base 27ba and a base 27bb is described. It shows. At this time,
the thicknesses of the base material 27 ta, the base material 27 tb, the base material 27 ba, and
the base material 27 bb are, for example, several tens of ?m or so.
[0070]
In the case where the upper side base material or the lower side base material is formed as a
laminated base material, for example, through holes formed in the electrode portion 28 eti, the
electrode 36 eti, the electrode 36 ebi, and the electrode portion 28 ebi, through holes pt1i, pt2i,
pb1i and pb2i It can be formed as In addition, when calling it a "through hole" by this
specification, the formation method of the conductive layer to the inner wall of a hole shall not
be limited to metal plating.
[0071]
By making the upper side base material 27t into a lamination | stacking base material, it also
becomes easy to make the upper side base material 27t into a base material in which the level |
step difference was formed. The opposing surface of the upper base 27t to the diaphragm Di is
convex with respect to the surface of the electrode 36eti formed on the upper base 27t, whereby
the diaphragm Di and the electrode 36eti formed on the upper base 27t are provided. It can
prevent contact with In addition, it is possible to form a wiring pattern inside the upper side base
material, and electrically connect an electrode facing the diaphragm part and a wiring pattern
formed inside the base material through the through hole. The lower base 27b can also be
configured the same as the upper base 27t.
[0072]
[Outline of Operation of Electro-acoustic Conversion System] Next, an outline of the operation of
04-05-2019
21
the electro-acoustic conversion system according to the embodiment will be described with
reference to FIG. 8.
[0073]
FIG. 8 is a block diagram showing an example of a specific configuration of a signal processing
unit and an electro-acoustic conversion system according to an embodiment of the present
disclosure.
As shown in FIG. 8, the audio signal recorded by the digital method is input to the electroacoustic
conversion system 1 through the signal processing unit 41.
[0074]
Specifically, the signal processing unit 41 includes, for example, a preprocessing unit 43, an
oversampling unit 45, a ? ? conversion unit 47, and an encoder 49, and is configured as an
integrated circuit such as an FPGA (Field-Programmable Gate Array). Be done. An audio signal
sent from a digital audio player or the like is also called, for example, an optical digital input
terminal 40 and an audio interface (Digital Audio Interface Receiver (DIR, DAI). ) Is input to the
signal processing unit 41 via 42 and the like.
[0075]
The input signal to the signal processing unit 41 is first supplied to the preprocessing unit 43 as
necessary, and the preprocessing unit 43 performs preprocessing such as combining L channel
signal and R channel signal, adjusting volume (gain), equalizing, etc. Will be applied.
[0076]
The preprocessed input signal is then supplied to the oversampling unit 45.
The oversampling unit 45 performs oversampling on the input signal. The sampling frequency of
the input signal is, for example, 44.1 kHz or 48 kHz, and the oversampling ratio at this time is,
04-05-2019
22
for example, 8 times.
[0077]
The oversampled input signal is then supplied to the ?? converter 47. In the ?? conversion
section 47, ? ? ? modulation (also called ?? modulation) is performed on the input signal.
And the quantization noise (Quantization noise) resulting from the quantization error
(Quantization Error) is shaped. Specifically, the input signal is subjected to noise shaping in
which quantization noise distributed in a high frequency band is removed by a digital low pass
filter. Thereafter, the decimation filter reduces the quantization word length to the target number
of bits.
[0078]
Here, the target number of bits is determined by the number of electroacoustic transducers that
the electroacoustic transducer system has. For example, in the case of an electro-acoustic
conversion system in which 256 electro-acoustic transducers T0 to T255 are arrayed, the
quantization word length is reduced to 8 bits (2 <8> = 256) or less.
[0079]
The input signal with the reduced quantization word length is then supplied to the encoder 49.
The output from the ?? conversion unit 47 is, for example, an 8-bit binary code. The encoder
49 converts an 8-bit binary code into a thermometer code (Thermometer Code).
[0080]
Here, the thermometer code is a code in which a binary code of ?0? and ?1? is used to
represent a value by the number of continuous ?1s?. In the thermometer code expression, the
sequence of ?1? switches from a certain bit to the sequence of ?0?. Such a representation is
called a thermometer code because bit switching is similar to the thermometer display.
04-05-2019
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[0081]
For example, 5 expressed in decimal is expressed as 101 in a 3-bit binary code. On the other
hand, when 5 expressed in decimal is expressed by a thermometer code, it becomes 0011111.
This is expressed in decimal notation 5 is 0 * 1 <6> + 0 * 1 <5> + 1 * 1 <4> + 1 * 1 <3> + 1 * 1
<2> + 1 * 1 <1> + 1 * This corresponds approximately to the expression of 1 <0>.
[0082]
In the above-described example, the decimal number 5 is represented by a 7-bit thermometer
code. This is because seven bits are required to represent the maximum number 111 (7 in
decimal notation) that can be represented by a 3-bit binary code by a thermometer code.
Similarly, 255 bits are required to represent a number that can be represented by an 8-bit binary
code with a thermometer code.
[0083]
The output of the encoder 49 expressed by the thermometer code is supplied as a drive signal to
the driver circuit 9 at and the like. The individual drivers D1, D2,..., D4 shown in FIG. 8 are, for
example, 32-bit serial in / parallel out high breakdown voltage drivers. The driver D1 includes,
for example, a driver circuit 9at and a driver circuit 9ab. Similarly, driver D2 includes, for
example, driver circuit 9bt and driver circuit 9bb, driver D3 includes, for example, driver circuit
9ct and driver circuit 9cb, and driver D4 includes, for example, driver circuit 9dt and driver
circuit 9db. . As a matter of course, the drivers D1, D2, ..., D4 and the like may be disposed only
on one side of the upper side substrate or the lower side substrate.
[0084]
For the electrode formed on the lower substrate, which corresponds to one of the electrodes
formed on the upper substrate, an output opposite to that for the electrode formed on the upper
substrate is taken out. Ru. It is assumed that the thermometer code output from the encoder 49
is, for example, 0000 to 0011111 (5 in decimal notation). At this time, in the drivers D1, D2, ...,
D4, for example, five of the electrodes formed on the upper side substrate are set to a high
potential, and the diaphragms of the five electroacoustic transducers approach the upper side
04-05-2019
24
substrate Be in the That is, the number of ?1? s in a certain thermometer code indicates the
number of electroacoustic transducers in which the diaphragm portion is brought close to the
upper substrate. Note that the number of ?0? s in a certain thermometer code indicates the
number of electroacoustic transducers in which the diaphragm portion is brought close to the
lower substrate.
[0085]
When the electroacoustic conversion system 1 is in operation, the individual diaphragm portions
Di are either in a state of approaching the upper substrate or in a state of approaching the lower
substrate.
[0086]
For example, it is assumed that the number of electro-acoustic transducers included in the
electro-acoustic transducer system 1 is 256 in all.
As an initial state, for example, of the 256 electroacoustic transducers, the diaphragm part of
128 electroacoustic transducers is brought close to the upper base material, and the diaphragm
parts of the remaining 128 electroacoustic transducers are It is in a state of approaching the
lower substrate.
[0087]
From the initial state, for example, when a thermometer code which is 130 in decimal notation is
output from the encoder 49, one of the diaphragm portions of the 128 electroacoustic
transducers which are brought close to the lower substrate Two change to the state which
approached the upper substrate.
[0088]
Next, it is assumed that a thermometer code that is 125 in decimal notation is output from the
encoder 49.
Then, five of the diaphragm portions of the 130 electro-acoustic transducers brought close to the
04-05-2019
25
upper substrate change to a state approaching the lower substrate. That is, the number of
changed bits of the thermometer code corresponds to the number of electroacoustic transducers
to be driven before and after the change of the thermometer code.
[0089]
In this manner, electro-acoustic conversion is performed according to a change in a bit of the
thermometer code based on the drive signal represented by the thermometer code.
[0090]
Although FIG. 8 shows a configuration example in which the electro-acoustic conversion system
1 does not include the signal processing unit 41, the electro-acoustic conversion system 1 may
include the signal processing unit 41.
[0091]
Of the plurality of electroacoustic transducers, which one of the electroacoustic transducers is to
be driven can be set arbitrarily.
For example, it is also possible to equalize the operating time of the individual electroacoustic
transducers, or to select an electroacoustic transducer at a position where a delay corresponding
to a desired directivity occurs.
[0092]
By the way, in the digital speaker, the spatially synthesized result of the sound generated from
each of the electroacoustic transducers is the output from the electroacoustic transducer system.
Therefore, it is preferable that the acoustic characteristics of the individual electroacoustic
transducers are all equal.
[0093]
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When driving a large number of electroacoustic transducers simultaneously, the difference
between the individual electroacoustic transducers can be canceled out, so that the acoustic
characteristics of the individual electroacoustic transducers can be allowed to have some
variation. However, when the number of electro-acoustic transducers to be driven is small, the
choice of which one of the plurality of electro-acoustic transducers is driven decreases sharply.
[0094]
According to the present disclosure, the opposing surface of the diaphragm portion in the upper
base member is convex with respect to the surface of the electrode formed in the upper base
member, so that the diaphragm portion and the electrode formed in the upper base member
Contact can be prevented. Similarly, since the opposing surface of the diaphragm portion in the
lower side substrate is convex with respect to the surface of the electrode formed in the lower
side substrate, the diaphragm portion and the electrode formed in the lower side substrate
Contact can be prevented. Furthermore, according to the present disclosure, the amplitude of the
diaphragm portion can be easily managed by adjusting the thickness of the upper spacer and the
lower spacer. That is, according to the present disclosure, it is possible to suppress the variation
in the maximum displacement of the diaphragm part between the electroacoustic transducers,
and to suppress the variation in the acoustic characteristics of the individual electroacoustic
transducers. Therefore, according to the present disclosure, the performance of the
electroacoustic conversion system can be improved.
[0095]
According to the present disclosure, since it is not necessary to manufacture an electro-acoustic
transducer as a so-called MEMS, an electro-acoustic transducer and an array-like electro-acoustic
transducer and an electro-acoustic conversion system can be manufactured without complicating
the process. . Therefore, it is also easier to manufacture a large-sized electroacoustic transducing
system compared to the case of MEMS without requiring an enormous amount of time or cost.
[0096]
??? Second Embodiment> [Schematic Configuration of Electro-Acoustic Transducer System]
FIG. 9A is a plan view showing a configuration example of an electro-acoustic transducer system
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27
according to a second embodiment. FIG. 9B is a side view of the electro-acoustic transducer
system shown in FIG. 9A. FIG. 10 is an exploded perspective view of the electro-acoustic
transducer system shown in FIGS. 9A and 9B.
[0097]
As shown in FIGS. 9B and 10, the electro-acoustic conversion system 51 according to the second
embodiment roughly includes an upper base 57t, an upper spacer 55t, a vibrating member 53, a
lower spacer 55b, and a lower base. A material 57b is stacked in order. In the first embodiment, a
configuration example has been shown in which a material having a small conductor resistance is
selected as the vibrating member 3. However, in the second embodiment, the first embodiment is
characterized in that the vibrating member 53 mainly comprises a resin material. It differs from
the embodiment. By selecting a resin material as the material forming the vibrating member 53,
the displacement of each diaphragm can be increased, and the sound pressure obtained from the
electroacoustic conversion system 51 can be increased.
[0098]
The electroacoustic conversion system 51 has a plurality of electroacoustic transducers.
Individual electro-acoustic transducers are constituted by members arranged on the upper and
lower sides of the diaphragm part and the diaphragm part with a part of the vibrating member
53 as a diaphragm part. The plurality of electroacoustic transducers are arranged, for example, in
correspondence with the grid points to constitute an array of electroacoustic transducers. Each of
the plurality of electrodes formed on the upper side substrate 57t and the driver circuits 59at,
59bt, 59ct and 59dt disposed on the upper side substrate are electrically made by the wiring
pattern 58Wt formed on the upper side substrate 57t. Connected Similarly, each of the plurality
of electrodes formed on the lower base 57b and the driver circuits 59ab, 59bb, 59cb and 59db
disposed on the lower base 57b are formed on the lower base 57b. It is electrically connected by
the wiring pattern 58Wb.
[0099]
Next, the upper base 57t and the lower base 57b, the upper spacer 55t and the lower spacer
55b, and the vibrating member 53 will be described in order with reference to FIGS. The electroacoustic conversion system 51 has a substantially symmetrical configuration with respect to the
04-05-2019
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vibrating member 53. The configuration of the lower base 57b is substantially the same as the
configuration of the upper base 57t, and the configuration of the lower spacer 55b is
substantially the same as the configuration of the upper spacer 55t. Furthermore, the driver
circuits 59 at, 59 bt, 59 ct and 59 dt can have the same configuration as the driver circuits 9 at,
9 bt, 9 ct and 9 dt according to the first embodiment. Therefore, in the following description, the
specific description of the configuration of lower base material 57b, the specific description of
the configuration of lower spacer 55b, and driver circuits 59at, 59bt, 59ct, 59dt, 59ab, 59bb,
59cb and 59db The specific description of is omitted.
[0100]
(Upper Base Material) The upper base material 57t has a function as a support of the vibrating
member 53, and constitutes the outer shape of the electroacoustic conversion system 51.
Although FIG. 9A, FIG. 9B, and FIG. 10 showed the structural example by which the shape of the
upper side base material 57t was made flat form, it is not restricted to this. Further, the outer
shape of the upper side base material 57t is not limited to the square.
[0101]
11A is an enlarged view of a portion Q1 in FIG. As shown in FIG. 11A, for example, a plurality of
electrode portions and a plurality of wiring portions are formed on the main surface of the upper
side base material. A wiring pattern 58Wt is configured by the plurality of electrode portions and
the plurality of wiring portions formed on the upper side base material.
[0102]
In FIG. 11A, a U portion surrounded by a broken line corresponds to one unit of the plurality of
electroacoustic transducers. Each electrode portion 58eti is formed corresponding to one of the
plurality of electroacoustic transducers, and each electrode portion 58eti is electrically connected
to the driver circuit by an individual wiring portion 58wti. Be done.
[0103]
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11B is an enlarged view of a portion U shown in FIG. 11A. FIG. 11C is an enlarged view of a
portion corresponding to the U portion shown in FIG. 11A in the surface of the upper base
material facing the upper spacer. 11C is an enlarged view of one main surface of the upper base
material, but since the configuration of the lower base material 57b is substantially the same as
the configuration of the upper base material 57t, FIG. 11C is shown in FIG. It corresponds to the
figure which expands and shows Q5 part.
[0104]
As shown in FIG. 11C, a plurality of main surfaces of the upper side base material 57t
corresponding to one of the plurality of electroacoustic transducers are also provided on the
main surface facing the vibrating member 53. The electrodes are formed.
[0105]
As shown in FIGS. 11B and 11C, a through hole pthi is formed at, for example, the center of each
electrode portion 58eti.
Among the main surfaces of the upper base material 57t, the electrode 56eti formed on the main
surface facing the vibrating member 53 is an electrode formed on the main surface opposite to
the main surface by the through holes pthi. It is electrically connected to the unit 58eti.
Therefore, the drive voltage from the driver circuit is applied to the electrode 56 eti formed on
the main surface facing the vibrating member 53 through the electrode portion 58 eti, the wiring
portion 58 wti and the through hole pthi.
[0106]
The vibration of air generated with the vibration of the vibrating member 53 described later is
transmitted to the outside through the through hole pthi. Therefore, it is preferable that the
diameter of the through hole be as large as possible. On the other hand, from the viewpoint of
increasing the driving force to the vibrating member 53 as much as possible, it is preferable that
the area of the electrode 56 eti formed on the main surface facing the vibrating member 53 be
large. In particular, it is preferable that the transmission of electrostatic force to the central
portion of the diaphragm portion be large.
04-05-2019
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[0107]
Here, in the case of forming the through hole pthi at the center of the electrode portion 58eti, if
the diameter of the through hole pthi is reduced in order to prevent the electrostatic force acting
on the central portion of the diaphragm portion from being reduced, the flow of air is
interrupted. It will
[0108]
Therefore, in the configuration example shown in FIG. 11B, six through holes hht1i, hht2i, hht3i,
hht4i, hht5i and hht6i are provided so as to surround the through hole pthi formed at the center
of the electrode portion 58eti.
Six through holes hht1i, hht2i, hht3i, hht4i, hht5i and hht6i are arranged, for example, at
positions corresponding to the vertices of a regular hexagon centered on the through hole pthi.
11B and 11C, regions other than the electrode unit 58eti, the wiring unit 58wti, the electrode
56eti, the through hole pthi, and the through holes hht1i, hht2i, hht3i, hht4i, hht5i, and hht6i are
shaded.
[0109]
The diameter of the through holes pthi is, for example, about several mm or less, and the
diameters of the individual through holes hht1i, hht2i, hht3i, hht4i, hht5i, and hht6i are, for
example, about several mm or less.
[0110]
By forming the through hole in addition to the through hole, it is possible to reliably transmit the
vibration of the air generated along with the vibration of the vibrating member 53 to the outside
while ensuring the transmission of the electrostatic force to the central portion of the diaphragm
portion. it can.
[0111]
11B shows an example in which circular through holes and through holes are formed in each
electrode portion 58eti, but the number, position, shape, size and the like of the through holes
and through holes are limited to this. Absent.
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31
Also, for example, all the through holes may be through holes.
11B and 11C, the shape of the electrode 56eti formed on the main surface facing the vibrating
member 53 and the shape of the electrode portion 58eti formed on the main surface opposite to
the main surface are the same. Although the same example is shown, it is not limited to this.
[0112]
As a material which constitutes upper substrate 57t, for example, LTCC or MID can be used as in
the first embodiment. Alternatively, a printed circuit board can also be used as the upper
substrate 57t. For example, a paper phenol substrate in which a paper substrate is impregnated
with a phenol resin, a paper epoxy substrate in which a paper substrate is impregnated with an
epoxy resin, a glass composite substrate in which glass fiber is impregnated with an epoxy resin,
glass fibers And a glass epoxy substrate in which an epoxy resin is impregnated in a woven
fabric.
[0113]
The material constituting the upper base material 57t is not limited to this, and for example, a
resin material or glass may be used. Of course, the material forming the upper base 57t and the
material forming the lower base 57b may not be the same.
[0114]
As a material which comprises electrode part 58eti, wiring part 58wti, and electrode 56eti, the
material with small conductor resistance is preferable, for example, although copper, gold, silver,
aluminum, nickel, or these combination etc. can be mentioned, It is not limited.
[0115]
(Upper Spacer) FIG. 12A is an enlarged view of a portion Q2 in FIG.
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32
12A is an enlarged view of one main surface of the upper spacer 55t, but since the configuration
of the lower spacer 55b is substantially the same as the configuration of the upper spacer 55t,
FIG. 12A corresponds to the portion Q4 in FIG. This corresponds to the enlarged view.
[0116]
As shown in FIG. 12A, in the upper spacer 55t, a plurality of openings Ati are formed
corresponding to one of the plurality of electroacoustic transducers. In FIG. 12A, regions other
than the opening Ati are shown by hatching.
[0117]
The upper spacer 55t is a member for securing displacement in a direction toward the upper
base 57t of the vibrating member 53 described later. Therefore, the area of the individual
openings Ati is larger than the area of the individual electrodes 56 eti. The diameter of the
electrode 56 eti is, for example, several mm, while the diameter of the opening Ati is larger than
the diameter of the electrode 56 eti.
[0118]
As a material which comprises the upper side spacer 55t, the material excellent in electrical
insulation is preferable, for example, although resin material, glass, rubber etc. can be mentioned,
it is not restricted to these.
[0119]
(Vibration member) Drawing 12B is a mimetic diagram showing the section of the example of 1
composition of a vibration member.
In the first embodiment, a configuration example using a metal material such as stainless steel as
the vibrating member is shown, but in the second embodiment, the vibrating member 53 is
configured as a laminate of a resin material and a conductive material. Be done.
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[0120]
As shown to FIG. 12B, the vibration member 53 has the structure where the base material layer
53a, the conductive layer 53b, and the insulating layer 53c were laminated | stacked in order.
[0121]
The base layer 53a is, for example, a film made of a resin material.
By using a resin material for the base layer 53a, the displacement of the vibrating member 53
with respect to the electrostatic force applied to the vibrating member 53 can be made large.
Examples of resin materials that constitute the base material layer 53a include polyphenylene
sulfide (PPS), polyethylene terephthalate (Polyethylene terephthalate (PET)), polycarbonate
(Polycarbonate (PC)), and cycloolefin polymer (Cycloolefin Polymer (COP) ), Polyethersulfone
(PES), polyethylene naphthalate (PEN), triacetylcellulose (TAC), polyimide (Polyimide),
polymethylmethacrylate (PMMA), aramid (PM) Aramid (aromatic polyamide)) etc. can be
mentioned.
[0122]
The conductive layer 53 b is provided to set the potential of the vibrating member 53 to, for
example, the ground potential. As a material which comprises the conductive layer 53b, copper,
gold, silver, aluminum, nickel, or these combination etc. can be mentioned, for example. The
conductive layer 53 b is formed by vapor deposition, plating, sputtering or the like using the base
layer 53 a as a supporting base. Specifically, the conductive layer 53b is, for example, a vapor
deposition layer of gold.
[0123]
The insulating layer 53c is a layer provided to prevent a short circuit between the conductive
layer 53b and the electrode 56eti formed on the upper base 57t. As a material which comprises
the insulating layer 53c, a resin material can be mentioned, for example. Examples of the resin
material include polyimide, polyphenylene sulfide, polyethylene terephthalate, polycarbonate,
cycloolefin polymer, polyether sulfone, polyethylene naphthalate, triacetyl cellulose, polymethyl
04-05-2019
34
methacrylate, aramid and the like. For forming the insulating layer 53c, for example,
microgravure coating, wire bar coating, direct gravure coating, die coating, dip coating, spray
coating, reverse roll coating, curtain coating, comma coating, knife coating A method, a spin coat
method, etc. can be applied.
[0124]
As shown in FIG. 12A, in the upper spacer 55t, a plurality of openings Ati are formed
corresponding to one of the plurality of electroacoustic transducers. The distance between the
centers of the adjacent openings is, for example, several mm, and portions corresponding to the
plurality of openings Ati provided in the upper spacer 55t in the vibrating member 53
correspond to individual electroacoustic transducers. It functions as a diaphragm part.
[0125]
[Schematic Configuration of Arrayed Electroacoustic Transducer] FIG. 13A is a schematic view of
the electroacoustic transducer system according to the second embodiment as viewed from the
upper substrate side. 13A is a view showing one main surface of the upper base 57t, but since
the configuration of the lower base 57b is substantially the same as the configuration of the
upper base 57t, FIG. It corresponds also to the schematic viewed from the lower side base
material 57b side.
[0126]
As shown in FIG. 13A, a plurality of electro-acoustic transducers are arranged, for example, in
correspondence with lattice points to constitute an array-like electro-acoustic transducer 61. The
number of the plurality of electroacoustic transducers in the arrayed electroacoustic transducer
61 can be set arbitrarily. The arrangement of the plurality of electroacoustic transducers can also
be set arbitrarily. For example, a plurality of electroacoustic transducers can be arranged radially,
concentrically, polygonally, elliptically or the like.
[0127]
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35
The outer shape of the array-like electroacoustic transducer 61 can also be set arbitrarily. For
example, when the outer shape of the upper side base material 57t is rectangular, for example,
the driver circuits 59 at, 59 bt, 59 ct and 59 dt are disposed one by one on four sides of the
rectangular shape. At this time, it is also possible to divide a plurality of electroacoustic
transducers into a plurality of groups and associate the plurality of electroacoustic transducers
belonging to each group with each of the driver circuits 59at, 59bt, 59ct and 59dt. is there.
[0128]
For example, in FIG. 13A, the plurality of electro-acoustic transducers are divided into four
groups Gra, Grb, Grc, and Grd, and the plurality of electro-acoustic transducers belonging to the
first group Gra and the driver circuit 59 at The structural example connected by the wiring
pattern 58Wat is shown. In FIG. 13A, the plurality of electroacoustic transducers belonging to the
second group Grb are indicated by circles represented by broken lines, the plurality of
electroacoustic transducers belonging to the third group Grc are indicated by black circles, and ,
And a plurality of electroacoustic transducers belonging to the fourth group Grd are indicated by
shaded circles. For example, the plurality of electro-acoustic transducers belonging to the second
group Grb are connected with the driver circuit 59bt, and the plurality of electro-acoustic
transducers belonging to the third group Grc are connected with the driver circuit 59ct, The
plurality of electroacoustic transducers belonging to the fourth group Grd are connected to the
driver circuit 59dt.
[0129]
In FIG. 13A, although the plurality of electroacoustic transducers are divided into a plurality of
groups along a rectangular diagonal, the present invention is not limited to this example. The
number and arrangement of driver circuits can also be appropriately set in accordance with the
number and arrangement of a plurality of electroacoustic transducers.
[0130]
[Schematic Configuration of Electroacoustic Transducer] FIG. 13B is a schematic diagram
showing one unit of the electroacoustic transducer in the electroacoustic transducer system and
the array of electroacoustic transducers. Specifically, the electroacoustic transducer T3i is one of
a plurality of electrodes formed on the upper base material 57t, the upper spacer portion S3ti,
04-05-2019
36
the diaphragm portion D3i, the lower spacer portion S3bi, and the lower side. It is composed of
one of a plurality of electrodes formed on the base material 57b. In FIG. 13B, among the main
surfaces of the upper base material 57t, the electrode portion 58eti formed on the main surface
not facing the vibrating member 53 and the main surface of the upper base material 57t are
opposed to the vibrating member 53. The electrode 56 eti formed on the main surface on the
side, the upper spacer portion S 3 ti, and the diaphragm portion D 3 i are shown in a
superimposed state. Further, in FIG. 13B, the region other than the opening Ati of the upper
spacer portion S3 ti is shown by hatching.
[0131]
FIG. 14A is a schematic view showing the XIV-XIV cross section of FIG. 13B. As shown in FIG.
14A, the diaphragm D3i which is a part of the vibrating member 53 has an outer peripheral part
by the upper spacer S3ti which is a part of the upper spacer 55t and the lower spacer S3bi which
is a part of the lower spacer 55b. Be supported. Since the outer peripheral part of the diaphragm
part D3i is supported by the upper spacer part S3ti and the lower spacer part S3bi, the
displacement of the diaphragm part D3i in each electroacoustic transducer T3i is independent of
each other.
[0132]
The thickness of the upper spacer portion S3ti and the lower spacer portion S3bi is, for example,
about several tens of ?m. The thicknesses of the base material layer 53a, the conductive layer
53b, and the insulating layer 53c that constitute the vibrating member 53 are, for example,
several ?m in thickness, respectively. The thickness of the diaphragm portion D3i is the sum of
these values. The thickness of the upper side base material 57t and the lower side base material
57b is, for example, about 0.1 mm to 10 mm.
[0133]
In the configuration example shown in FIG. 14A, the electrode portion 58 eti and the electrode
56 eti, and the electrode portion 58 ebi and the electrode 56 ebi are each formed of a laminate of
a conductive layer 58 a made of gold and a conductive layer 58 c made of copper. The thickness
of the stacked body of the conductive layer 58a and the conductive layer 58c is, for example,
about several tens of ?m. The distance d1 between the boundary between the opening Ati and
04-05-2019
37
the other region and the peripheral edge of the electrode 56eti is, for example, about several tens
of ?m. Further, the distance d2 between the peripheral edge of the electrode 56eti and the
peripheral edge of the through hole is, for example, about 10 to 500 ?m.
[0134]
The displacement of the diaphragm portion D3i generates air vibration. The vibration of air
accompanying the displacement of the diaphragm portion D3i is transmitted to the outside
through the through holes and the through holes formed in the electrode portion 58eti and the
electrode 56eti and the electrode portion 58ebi and the electrode 56ebi.
[0135]
In the state where the diaphragm part D3i is not displaced, a gap of about several ?m is
provided between the surface of the diaphragm part D3i and the surface of the electrode 56eti.
In the first embodiment, since the vibrating member 3 is made of a conductive material, the
surface of the upper base 7t facing the diaphragm portion Di is convex with respect to the
surface of the electrode 6eti. The In the second embodiment, since the conductive layer 53b of
the vibrating member 53 is covered by the base layer 53a and the insulating layer 53c, the
diaphragm portion D3i and the electrode 56eti formed on the upper base 57t are in contact with
each other. Even short circuit does not occur. Of course, as in the first embodiment, the surface
of the upper base 57t facing the diaphragm D3i is convex with respect to the surface of the
electrode 56eti, and the surface of the lower base 57b facing the diaphragm D3i is It may be
convex with respect to the surface of the electrode 56ebi.
[0136]
FIG. 14B is an XZ cross-sectional view showing another configuration example of the
electroacoustic transducer. In the electroacoustic transducer T4i shown in FIG. 14B, the surface
of the upper base 67t facing the diaphragm D3i is convex with respect to the surface of the
electrode 66eti. Further, the surface of the lower side base material 67b that faces the diaphragm
portion D3i is convex with respect to the surface of the electrode 66ebi. In this way, variation in
the maximum displacement of the diaphragm between the electroacoustic transducers is
suppressed, and variation in the acoustic characteristics of the individual electroacoustic
transducers is suppressed.
04-05-2019
38
[0137]
??? Modifications> Although the preferred embodiments have been described above,
preferred specific examples are not limited to the above description, and various modifications
are possible.
[0138]
For example, the shape of the arrayed electroacoustic transducer or the electroacoustic
transducer system may be a curved shape as a whole. The number, arrangement, and shape of
the plurality of electroacoustic transducers in the arrayed electroacoustic transducer or the
electroacoustic transducer system can be set arbitrarily. Further, the number, arrangement, and
shape of the through holes formed in the electrode can be arbitrarily set.
[0139]
The technology of the present disclosure can also be applied to, for example, a television, a radio,
an audio, a camera, a video camera, a laptop computer, a personal digital assistance (PDA), a
smartphone, a mobile phone, and the like. The technology of the present disclosure is particularly
suitable for, for example, an on-vehicle speaker of an electric vehicle, because the digital speaker
consumes less power than an analog speaker. The technology of the present disclosure can be
applied not only to portable electronic devices but also to digital signage installed in buildings,
signs, and the like.
[0140]
The configurations, methods, shapes, materials, numerical values, and the like described in the
above-described embodiments are merely examples, and different configurations, methods,
shapes, materials, numerical values, and the like may be used as needed. The configurations,
methods, shapes, materials, numerical values, and the like of the above-described embodiments
can be combined with one another without departing from the spirit of the present disclosure.
04-05-2019
39
[0141]
For example, the present disclosure can also be configured as follows. (1) A first spacer, a second
spacer, a diaphragm whose outer peripheral portion is supported by the first spacer and the
second spacer, and at least a part of a main surface facing the diaphragm A first base on which a
first electrode is formed; and a second base on which a second electrode is formed on at least a
part of a main surface facing the diaphragm. Material facing the diaphragm, the surface facing
the diaphragm being more convex than the surface of the first electrode, and the surface facing
the diaphragm facing the second substrate is the second An electro-acoustic transducer which is
more convex to the diaphragm than a surface of an electrode. (2) The electroacoustic transducer
according to (1), wherein the material forming the diaphragm is a metal material. (3) The
electroacoustic transducer according to (2), wherein the metal material is stainless steel. (4) The
electro-acoustic transducer according to (2) or (3), wherein a central portion of the diaphragm is
supported by a plurality of arms formed between the outer peripheral portion and the central
portion. (5) The vibration of air generated by the displacement of the diaphragm propagates to
the outside through the openings formed in the first electrode and the second electrode. An
electroacoustic transducer according to any one of the preceding claims. (6) The electroacoustic
transducer according to (5), wherein the number of openings formed in the first electrode is two
or more. (7) The electroacoustic transducer according to (5) or (6), wherein the number of
openings formed in the second electrode is two or more. (8) A first wiring portion formed on the
surface of the first base, and a second wiring portion formed on the surface of the second base,
further comprising: The electrode and the first wiring portion are electrically connected via at
least one of the two or more openings formed in the first electrode, and the second electrode and
the second The electro-acoustic transducer according to (7), wherein the wiring portion is
electrically connected via at least one of the two or more openings formed in the second
electrode. (9) The material according to any one of (1) to (8), wherein the material constituting at
least one of the first base and the second base is a fired body of a metal oxide. Electro-acoustic
transducer. (10) The electroacoustic transducer according to any one of (1) to (8), wherein the
material forming at least one of the first base and the second base is a resin material. . (11) A first
spacer, a second spacer, a plurality of openings formed in the first spacer, and a plurality of
openings corresponding to the plurality of openings formed in the second spacer A region
formed independently of each other and vibrated to be supported by the first spacer and the
second spacer, and a diaphragm formed on the first spacer on a main surface facing the
diaphragm. A plurality of first base members having electrodes formed respectively in a plurality
of regions corresponding to a plurality of openings; and a plurality of the plurality of spacers
formed on the second spacer on the main surface opposite to the diaphragm. An electro-acoustic
transducer comprising a second base material in which an electrode is formed in each of a
plurality of regions corresponding to the opening, and in which each of the regions
independently vibrated in the diaphragm is a unit Equipped with Array of electroacoustic
04-05-2019
40
transducers.
(12) The arrayed electroacoustic transducer according to (11), wherein the plurality of
electroacoustic transducers are arranged corresponding to lattice points. (13) A first spacer, a
second spacer, a plurality of openings formed in the first spacer, and a plurality of openings
corresponding to the plurality of openings formed in the second spacer A region formed
independently of each other and vibrated to be supported by the first spacer and the second
spacer, and a diaphragm formed on the first spacer on a main surface facing the diaphragm. A
plurality of first base members having electrodes formed respectively in a plurality of regions
corresponding to a plurality of openings; and a plurality of the plurality of spacers formed on the
second spacer on the main surface opposite to the diaphragm. A second base material in which
an electrode is formed in each of a plurality of regions corresponding to the opening, and a main
surface of the main surface of the first base material on the opposite side to the main surface
facing the diaphragm. Disposed on a surface and formed on the first substrate One or more
upper surface side driver circuits having electrical connection with several electrodes, and among
the main surfaces of the second base material, disposed on the main surface opposite to the main
surface facing the diaphragm. And one or more bottom side driver circuits having an electrical
connection with the plurality of electrodes formed on the second base material, and each of the
independently vibrated areas in the diaphragm. An electro-acoustic conversion system
comprising a plurality of electro-acoustic transducers independently driven in response to drive
signals from the one or more top-side driver circuits or the one or more bottom-side driver
circuits in units of. (14) The upper surface side driver circuit and the bottom surface side driver
circuit are each 2 or more, The outer shape of the first base material and the outer shape of the
second base material are rectangular, The upper surface side of the 2 or more upper surface side
The driver circuit is disposed along the periphery of the first substrate, and the two or more
bottom side driver circuits are disposed along the periphery of the second substrate (13) Electroacoustic conversion system. (15) The plurality of electro-acoustic transducers are divided into
two or more groups, and one or more electro-acoustic transducers belonging to each group are
included in each group among the two or more top side driver circuits. The electro-acoustic
conversion system according to (14) driven by the bottom side driver circuit corresponding to
each group among the corresponding top side driver circuit and the two or more bottom side
driver circuits. (16) The electricity according to (15), wherein the plurality of electroacoustic
transducers are arranged in a rectangular shape corresponding to the grid points, and divided
into two or more groups based on the diagonal of the rectangular shape. Sound conversion
system.
[0142]
1, 51: electro-acoustic conversion system 3, 53: vibrating member 5t, 55t: upper spacer 5b, 55b:
lower spacer 6eti, 36eti, 36ebi, electrode 7t, 27t, 57t, 67t иии Upper base 7b, 27b, 57b, 67b иии
04-05-2019
41
Lower base 8Wt, 8Wb, 58Wt, 58Wb иии Wiring pattern 9at, 9bt, 9ct, 9dt ииии Driver circuit 11, 61 ииии
Array-like electroacoustic transducer 41: Signal processor 41 Ti, T2i, T3i, T4i: Electroacoustic
transducer Di, D3i: Diaphragm part Hti, Ati: Opening Sti, S3ti,. и Upper spacer portion Sbi, S3 bi и и
и Lower spacer portion h1i, h2i, h3i, h4i и и и Arms ht1i, ht2i и и и Through holes pt1i, pt2i, pb1i, p
2i иии through hole
04-05-2019
42
Each electrode portion 8eti is formed corresponding to one of the
plurality of electroacoustic transducers, and each electrode portion 8eti is electrically connected
to a driver circuit described later by an individual wiring portion 8wti. Connected to
[0030]
For example, two through holes ht1i and ht2i are formed in each of the electrode portions 8eti.
The through holes ht1i and ht2i are air holes formed to allow air to enter and exit with the
vibration of the vibrating member 3 described later. Although FIG. 3A shows an example in which
two circular through holes ht1i and ht2i are formed in each of the electrode parts 8eti, the
number, position, shape, size and the like of the through holes are not limited to this.
[0031]
FIG. 3B is an enlarged view of a portion corresponding to the portion P1 shown in FIG. 2 on the
surface of the upper base material facing the upper spacer. In FIG. 3B, a U portion surrounded by
a broken line corresponds to one unit of the plurality of electroacoustic transducers. Note that
FIG. 3B is an enlarged view of one main surface of the upper side base material, but since the
configuration of the lower side base material 7b is substantially the same as the configuration of
the upper side base material 7t, FIG. It corresponds to the figure which expands and shows P5
part shown to.
04-05-2019
10
[0032]
As shown in FIG. 3B, a plurality of main surfaces of the upper side base material 7t
corresponding to one of the plurality of electroacoustic transducers are also provided on the
main surface on the side facing the vibrating member 3 The electrodes are formed. Among the
main surfaces of the upper side base material 7t, the electrode 6eti formed on the main surface
facing the vibrating member 3 is electrically connected to the electrode portion 8eti formed on
the main surface opposite to the main surface. It is connected to the. Therefore, a driving voltage
from a driver circuit described later is applied to the electrode 6eti formed on the main surface
on the side facing the vibrating member 3 via the electrode portion 8eti and the wiring portion
8wti.
[0033]
FIG. 3C is an enlarged view of one of the plurality of electrodes in FIG. 3B and the periphery
thereof. In FIG. 3C, regions other than the electrode 6eti and the through holes ht1i and ht2i are
shown by hatching.
[0034]
As shown in FIG. 3C, the electrode 6 eti is, for example, in a shape (so-called dumbbell shape) in
which two places of the circumference are directed to the center. The surface of the electrode 6
eti is recessed with respect to the surface of the upper base 7 t facing the vibrating member 3.
That is, the dumbbell-shaped narrowed portions CP1i and CP2i protrude toward the vibrating
member 3. The dumbbell-shaped narrowed portions CP1i and CP2i function as stoppers for
preventing the contact between the vibrating member 3 and the electrode 6eti as described later.
[0035]
From the viewpoint of increasing the driving force with respect to the vibrating member 3 as
much as possible, it is preferable that the area of the electrode 6eti formed on the main surface
04-05-2019
11
facing the vibrating member 3 be large. On the other hand, from the viewpoint of increasing the
area in which wiring can be performed, it is preferable that the area of the electrode portion 8eti
formed on the main surface on the side not facing the vibrating member 3 be small. Therefore, in
FIGS. 3A to 3C, the shape of the electrode 6eti formed on the main surface facing the vibrating
member 3 and the shape of the electrode portion 8eti formed on the main surface opposite to the
main surface Although the example which is not identical is shown, the shapes of the electrode
6eti and the electrode portion 8eti are not limited to this.
[0036]
As a material which constitutes upper substrate 7t, for example, low temperature co-fired
ceramics called LTCC (Low Temperature Co-fired Ceramics) can be used. LTCC is a ceramic
material obtained by adding a glass-based material to aluminum oxide and firing it at a
temperature of about 900 ░ C. or less. The firing temperature of LTCC is lower at around 900 ░
C or less compared to the case where no glass-based material is added, so it is also possible to
fire a substrate on which a wiring pattern using copper or silver with low conductor resistance is
formed. is there. Therefore, for example, the laminated base material including the substrate on
which the wiring pattern is formed may be fired to form the laminated base material having the
wiring pattern formed therein as the upper base material 7t.
[0037]
For example, a circuit molded part called MID (Molded Interconnect Device) may be used as the
upper base 7t. The MID is a circuit molded part in which an electric circuit is formed on a resin
structure, and since the electric circuit can be formed only by plating or vapor deposition, it has
the feature of being environmentally friendly. By applying the MID to the upper side base
material 7t, it becomes easy to make the upper side base material 7t a base material on which a
level difference is formed.
[0038]
As a material which constitutes upper substrate 7t, it is not restricted to this, for example, resin
material, glass, etc. may be used. Of course, the material forming the upper base 7t and the
material forming the lower base 7b may not be the same.
04-05-2019
12
[0039]
As a material which comprises electrode part 8eti, wiring part 8wti, and electrode 6eti, the
material with small conductor resistance is preferable, for example, although copper, gold, silver,
aluminum, nickel, or these combination etc. can be mentioned, It is not limited. From the
viewpoint of preventing the manufacturing process from being complicated, it is preferable that
the electrode portion 8eti, the wiring portion 8wti and the electrode 6eti be made of the same
material. The electrode portion 8eti, the wiring portion 8wti and the electrode 6eti can be formed
by, for example, plating, vapor deposition, sputtering or the like.
[0040]
(Upper Spacer) FIG. 4A is an enlarged view of a portion P2 in FIG. 4A is an enlarged view of one
main surface of the upper spacer 5t, but since the configuration of the lower spacer 5b is
substantially the same as the configuration of the upper spacer 5t, FIG. 4A corresponds to the
portion P4 in FIG. This corresponds to the enlarged view.
[0041]
As shown in FIG. 4A, in the upper spacer 5t, a plurality of openings Hti are formed corresponding
to one of the plurality of electroacoustic transducers. In FIG. 4A, regions other than the opening
Hti are shown by hatching.
[0042]
The upper spacer 5t is a member for securing displacement in a direction toward the upper base
7t in the vibrating member 3 described later. Therefore, the area of the individual openings Hti is
larger than the area of the individual electrodes 6eti. When a circle including the electrode 6eti is
assumed, the diameter of the circle is, for example, several mm, while the diameter of the
opening Hti is larger than the diameter of the circle.
[0043]
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13
As a material which comprises the upper side spacer 5t, the material excellent in electrical
insulation is preferable, for example, although resin material, glass, rubber etc. can be mentioned,
it is not restricted to these.
[0044]
(Vibrating Member) FIG. 4B is an enlarged view of a portion P3 in FIG.
The vibrating member 3 is a vibrating plate for generating air vibration in electroacoustic
conversion.
[0045]
As shown in FIG. 4B, a plurality of diaphragm portions Di are arranged in the vibrating member
3. The diaphragm portion Di is disposed at a position corresponding to the plurality of openings
Hti provided in the upper spacer 5t. Therefore, each diaphragm part Di is independently made
freely vibrating along the direction (Z-axis direction) perpendicular to the paper surface.
[0046]
In the present disclosure, the diaphragm portions Di of individual electroacoustic transducers are
arranged on a common member. Therefore, according to the present disclosure, an
electroacoustic transducer and an array of electroacoustic transducer and an electroacoustic
transducer system can be manufactured without complicating the process.
[0047]
As a material which comprises the vibration member 3, the material with small conductor
resistance is preferable, for example, a metal material can be mentioned. Examples of the metal
material include stainless steel, titanium, aluminum, beryllium, magnesium, titanium boride,
duralumin and the like. Stainless steel is an alloy in which iron contains chromium and nickel.
The stainless steel can be appropriately selected from austenitic stainless steel or ferritic
04-05-2019
14
stainless steel or martensitic stainless steel. For example, in accordance with JIS standard
notation, SUS304, SUS304L, SUS316, SUS310S, SUS309S, SUS303, and SUS301. SUS430,
SUS440C, SUS420J2, and SUS410S are suitable.
[0048]
FIG. 4C is an enlarged view of one of the plurality of diaphragms in FIG. 4B and the periphery
thereof. When a metal material such as stainless steel is used as the material constituting the
vibrating member 3, for example, the shapes Di of the individual diaphragms tend to vibrate in
order to make the displacement of the individual diaphragms Di as large as possible. It is
preferred that it be shaped. Specifically, for example, as shown in FIG. 4C, it is preferable that
slits be provided in the outer peripheral portion of each diaphragm portion Di.
[0049]
In the configuration example shown in FIG. 4C, four slits s1i, s2i, s3i and s4i are formed in the
outer peripheral part of each diaphragm part. That is, the central part of the diaphragm part Di
shown in FIG. 4C is supported by the four arms h1i, h2i, h3i and h4i. In addition, in FIG. 4B and
FIG. 4C, area | regions other than a slit were shown by meshing.
[0050]
Since the four arms h1i, h2i, h3i and h4i function as cantilevers, the displacement of the central
portion of the diaphragm Di can be increased compared to the case where the slit is not formed.
Although FIG. 4C shows an example in which four slits s1i, s2i, s3i and s4i are formed on the
outer peripheral portion of each diaphragm portion Di, the number, position, shape, size and the
like of the slits are set to this. It is not limited.
[0051]
(Driver Circuit) The driver circuit is a circuit that supplies a current for driving each of the
electroacoustic transducers, and is formed of, for example, a combination of transistors. As
shown in FIGS. 1A and 1B and FIG. 2, for example, four driver circuits 9 at, 9 bt, 9 ct and 9 dt are
04-05-2019
15
disposed on the upper base 7 t. The electrode 6eti formed on the upper base 7t has an electrical
connection with any of the driver circuits 9at, 9bt, 9ct and 9dt disposed on the upper base 7t.
Similarly, for example, four driver circuits 9ab, 9bb, 9cb and 9db are disposed on the lower base
7b. Each of the plurality of electrodes formed on the lower side substrate 7b has electrical
connection with any of the driver circuits 9ab, 9bb, 9cb and 9db arranged on the lower side
substrate 7b.
[0052]
For example, when the vibrating member 3 is set to the ground potential, the electrode 6eti
corresponding to one electroacoustic transducer out of the plurality of electrodes formed on the
upper base 7t is set to a high potential, the electroacoustic transducer The electrostatic force acts
on the diaphragm portion Di of the first and second diaphragm portions Di, and the diaphragm
portion Di approaches the upper base 7t. That is, the displacement in the + Z direction of the
diaphragm portion Di of one electroacoustic transducer is controlled by the driver circuit
disposed on the upper base 7t. At this time, among the plurality of electrodes formed on the
lower side substrate 7b, the electrode corresponding to the electroacoustic transducer is set to
the ground potential.
[0053]
Similarly, the displacement of the diaphragm part Di of one electroacoustic transducer in the -Z
direction is controlled by a driver circuit disposed on the lower substrate 7b. Thus, the individual
electroacoustic transducers are driven by driver circuits disposed on the upper substrate 7t and
the lower substrate 7b.
[0054]
The driver circuit supplies a drive current for bringing the diaphragm portion of the
electroacoustic transducer closer to the upper substrate or the lower substrate according to the
input signal, as described later. The manufacturer of the electro-acoustic conversion system 1
can appropriately set which one of the plurality of electro-acoustic transducers is to be driven.
[0055]
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16
[Schematic Configuration of Arrayed Electroacoustic Transducer] FIG. 5A is a schematic view of
the electroacoustic transducer system according to the first embodiment as viewed from the
upper substrate side. 5A is a view showing one principal surface of the upper base 7t, but since
the configuration of the lower base 7b is substantially the same as the configuration of the upper
base 7t, FIG. It corresponds also to the schematic seen from the lower side base material 7b side.
[0056]
As shown in FIG. 5A, a plurality of electro-acoustic transducers are arranged, for example, in
correspondence with lattice points to constitute an array-like electro-acoustic transducer 11. The
number of the plurality of electroacoustic transducers in the arrayed electroacoustic transducer
11 can be set arbitrarily. Specifically, the number of electroacoustic transducers in the array-like
electroacoustic transducer 11 can be, for example, one less than the power of 2 or 2 of the
power. By setting the number of the plurality of electroacoustic transducers to a power of 2, for
example, it is possible to prevent the circuit for generating drive signals for the plurality of
electroacoustic transducers from being complicated.
[0057]
The arrangement of the plurality of electroacoustic transducers can also be set arbitrarily. For
example, a plurality of electroacoustic transducers can be arranged radially, concentrically,
polygonally, elliptically or the like.
[0058]
The outer shape of the arrayed electroacoustic transducer 11 can also be set arbitrarily. For
example, when the outer shape of the upper base 7t is rectangular, for example, the driver
circuits 9at, 9bt, 9ct and 9dt are disposed one by one on four sides of the square. At this time, it
is also possible to divide a plurality of electroacoustic transducers into a plurality of groups and
associate the plurality of electroacoustic transducers belonging to each group with each of the
driver circuits 9at, 9bt, 9ct and 9dt. is there.
04-05-2019
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[0059]
For example, in FIG. 5A, the plurality of electroacoustic transducers are divided into four groups
Ga, Gb, Gc and Gd, and the plurality of electroacoustic transducers belonging to the first group Ga
and the driver circuit 9 at The structural example connected by the wiring pattern 8 Watt is
shown. In FIG. 5A, the plurality of electroacoustic transducers belonging to the second group Gb
are indicated by circles represented by broken lines, and the plurality of electroacoustic
transducers belonging to the third group Gc are indicated by black circles. , And a plurality of
electroacoustic transducers belonging to the fourth group Gd are indicated by shaded circles. For
example, the plurality of electro-acoustic transducers belonging to the second group Gb are
connected with the driver circuit 9bt, and the plurality of electro-acoustic transducers belonging
to the third group Gc are connected with the driver circuit 9ct, The plurality of electroacoustic
transducers belonging to the fourth group Gd are connected to the driver circuit 9dt.
[0060]
As described above, by dividing the plurality of electroacoustic transducers into a plurality of
groups and arranging a plurality of driver circuits corresponding to each group, it is possible to
prevent the wiring pattern from becoming complicated. In FIG. 5A, although the plurality of
electroacoustic transducers are divided into a plurality of groups along a rectangular diagonal,
the present invention is not limited to this example. The number and arrangement of driver
circuits can also be appropriately set in accordance with the number and arrangement of a
plurality of electroacoustic transducers.
[0061]
[Schematic Configuration of Electro-Acoustic Transducer] FIG. 5B is a schematic diagram
showing one unit of the electro-acoustic transducer in the electro-acoustic transducer system and
the array-like electro-acoustic transducer. Specifically, the electroacoustic transducer Ti is one of
a plurality of electrodes formed on the upper base 7t, the upper spacer portion Sti, the
diaphragm portion Di, the lower spacer portion Sbi, and the lower side. It comprises one of a
plurality of electrodes formed on the base 7b. In FIG. 5B, among the main surfaces of the upper
base 7t, the electrode portion 8eti formed on the main surface not facing the vibrating member 3
and the main surface of the upper base 7t are opposed to the vibrating member 3. It shows a
state in which the electrode 6eti formed on the main surface on the side, the upper spacer
portion Sti, and the diaphragm portion Di are superimposed. In FIG. 5B, of the main surfaces of
04-05-2019
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the lower base 7b, the electrode 8ebi formed on the main surface not facing the vibrating
member 3 and the main surface of the lower base 7b are opposed to the vibrating member 3.
The illustration of the electrode 6ebi and the lower spacer portion Sbi formed on the main
surface on the side of the upper side is omitted. Further, in FIG. 5B, the region other than the
opening Hti of the upper spacer portion Sti is shown by hatching.
[0062]
FIG. 6A is a schematic view showing a VIxz-VIxz cross section of FIG. 5B. FIG. 6B is a schematic
view showing a VIyz-VIyz cross section of FIG. 5B. As shown to FIG. 6A and FIG. 6B, the
diaphragm part Di which is a part of vibration member 3 is lower spacer part Sbi which is a part
of upper spacer part Sti which is a part of upper spacer 5t, and lower spacer 5b. The outer
peripheral portion is supported by the
[0063]
An upper base 7t and a lower base are provided by applying a drive voltage according to an
input audio signal to the electrode 6eti formed on the upper base 7t or the electrode 6ebi formed
on the lower base 7b. The diaphragm portion Di is displaced between the members 7b. A driving
voltage from a driver circuit is applied to the electrode 6ebi via the electrode portion 8ebi and
the wiring portion 8wbi. In addition, since the outer peripheral part of the diaphragm part Di is
supported by the upper side spacer part Sti and the lower side spacer Sbi, the displacement of
the diaphragm part Di in each electroacoustic transducer Ti is each independent.
[0064]
The thickness of the upper spacer portion Sti and the lower spacer portion Sbi is, for example,
about several ?m. By adjusting the thickness of the upper spacer 5t and the lower spacer 5b, the
amplitude of the diaphragm portion Di can be easily managed. The thickness of the diaphragm
portion Di is, for example, about several ?m.
[0065]
04-05-2019
19
The displacement of the diaphragm portion Di generates air vibration. The vibration of air
accompanying the displacement of the diaphragm part Di is made through the two through holes
ht1i and ht2i formed in the electrode part 8eti and the electrode 6eti and the two through holes
hb1i and hb2i formed in the electrode part 8ebi and the electrode 6ebi It is transmitted to the
outside. By transmitting the vibration of air accompanying the displacement of the diaphragm
portion Di to the outside, electroacoustic conversion is performed in each of the electroacoustic
transducers Ti. The diameters of the individual through holes ht1i, ht2i, hb1i and hb2i are, for
example, several mm or less.
[0066]
As shown in FIG. 6A, in the upper substrate, portions PR1i and PR2i corresponding to the
dumbbell shaped waisted portions CP1i and CP2i shown in FIG. 3C protrude toward the central
portion of the electroacoustic transducer Ti. In addition, the surface of the upper base 7t facing
the diaphragm portion Di is convex with respect to the surface of the electrode 6eti. The
thickness of the upper base 7t is, for example, about several tens of ?m, and for example, a gap
of about 1 ?m to 100 ?m between the surface of the upper base 7t facing the diaphragm
portion Di and the surface of the electrode 6eti Is formed. That is, gp shown in FIG. 6B is about 1
?m to 100 ?m. Similarly, the surface of the lower base 7b opposite to the diaphragm portion Di
is convex with respect to the surface of the electrode 6ebi.
[0067]
The surface of the upper base 7t facing the diaphragm portion Di is convex with respect to the
surface of the electrode 6eti formed on the upper base 7t, and hence the electrode formed on the
diaphragm Di and the upper base 7t Contact with 6eti is prevented. Similarly, since the surface of
the lower base 7b opposite to the diaphragm Di is convex with respect to the surface of the
electrode 6ebi formed on the lower base 7b, the diaphragm Di and the lower base The contact
with the electrode 6ebi formed on 7b is prevented.
[0068]
FIG. 7A is an XZ sectional view showing another configuration example of the electroacoustic
transducer. FIG. 7B is a YZ sectional view showing another configuration example of the
electroacoustic transducer. FIG. 7A is a diagram corresponding to FIG. 6A, and FIG. 7B is a
04-05-2019
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diagram corresponding to FIG. 6B.
[0069]
As shown in FIGS. 7A and 7B, the upper base or lower base of the electroacoustic transducer T2i
may be configured as a laminated base. 7A and 7B, an example in which the upper base 27t is
formed as a laminated base of the base 27ta and the base 27tb, and the lower base 27b is
formed as a laminated base of the base 27ba and a base 27bb is described. It shows. At this time,
the thicknesses of the base material 27 ta, the base material 27 tb, the base material 27 ba, and
the base material 27 bb are, for example, several tens of ?m or so.
[0070]
In the case where the upper side base material or the lower side base material is formed as a
laminated base material, for example, through holes formed in the electrode portion 28 eti, the
electrode 36 eti, the electrode 36 ebi, and the electrode portion 28 ebi, through holes pt1i, pt2i,
pb1i and pb2i It can be formed as In addition, when calling it a "through hole" by this
specification, the formation method of the conductive layer to the inner wall of a hole shall not
be limited to metal plating.
[0071]
By making the upper side base material 27t into a lamination | stacking base material, it also
becomes easy to make the upper side base material 27t into a base material in which the level |
step difference was formed. The opposing surface of the upper base 27t to the diaphragm Di is
convex with respect to the surface of the electrode 36eti formed on the upper base 27t, whereby
the diaphragm Di and the electrode 36eti formed on the upper base 27t are provided. It can
prevent contact with In addition, it is possible to form a wiring pattern inside the upper side base
material, and electrically connect an electrode facing the diaphragm part and a wiring pattern
formed inside the base material through the through hole. The lower base 27b can also be
configured the same as the upper base 27t.
[0072]
[Outline of Operation of Electro-acoustic Conversion System] Next, an outline of the operation of
04-05-2019
21
the electro-acoustic conversion system according to the embodiment will be described with
reference to FIG. 8.
[0073]
FIG. 8 is a block diagram showing an example of a specific configuration of a signal processing
unit and an electro-acoustic conversion system according to an embodiment of the present
disclosure.
As shown in FIG. 8, the audio signal recorded by the digital method is input to the electroacoustic
conversion system 1 through the signal processing unit 41.
[0074]
Specifically, the signal processing unit 41 includes, for example, a preprocessing unit 43, an
oversampling unit 45, a ? ? conversion unit 47, and an encoder 49, and is configured as an
integrated circuit such as an FPGA (Field-Programmable Gate Array). Be done. An audio signal
sent from a digital audio player or the like is also called, for example, an optical digital input
terminal 40 and an audio interface (Digital Audio Interface Receiver (DIR, DAI). ) Is input to the
signal processing unit 41 via 42 and the like.
[0075]
The input signal to the signal processing unit 41 is first supplied to the preprocessing unit 43 as
necessary, and the preprocessing unit 43 performs preprocessing such as combining L channel
signal and R channel signal, adjusting volume (gain), equalizing, etc. Will be applied.
[0076]
The preprocessed input signal is then supplied to the oversampling unit 45.
The oversampling unit 45 performs oversampling on the input signal. The sampling frequency of
the input signal is, for example, 44.1 kHz or 48 kHz, and the oversampling ratio at this time is,
04-05-2019
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for example, 8 times.
[0077]
The oversampled input signal is then supplied to the ?? converter 47. In the ?? conversion
section 47, ? ? ? modulation (also called ?? modulation) is performed on the input signal.
And the quantization noise (Quantization noise) resulting from the quantization error
(Quantization Error) is shaped. Specifically, the input signal is subjected to noise shaping in
which quantization noise distributed in a high frequency band is removed by a digital low pass
filter. Thereafter, the decimation filter reduces the quantization word length to the target number
of bits.
[0078]
Here, the target number of bits is determined by the number of electroacoustic transducers that
the electroacoustic transducer system has. For example, in the case of an electro-acoustic
conversion system in which 256 electro-acoustic transducers T0 to T255 are arrayed, the
quantization word length is reduced to 8 bits (2 <8> = 256) or less.
[0079]
The input signal with the reduced quantization word length is then supplied to the encoder 49.
The output from the ?? conversion unit 47 is, for example, an 8-bit binary code. The encoder
49 converts an 8-bit binary code into a thermometer code (Thermometer Code).
[0080]
Here, the thermometer code is a code in which a binary code of ?0? and ?1? is used to
represent a value by the number of continuous ?1s?. In the thermometer code expression, the
sequence of ?1? switches from a certain bit to the sequence of ?0?. Such a representation is
called a thermometer code because bit switching is similar to the thermometer display.
04-05-2019
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[0081]
For example, 5 expressed in decimal is expressed as 101 in a 3-bit binary code. On the other
hand, when 5 expressed in decimal is expressed by a thermometer code, it becomes 0011111.
This is expressed in decimal notation 5 is 0 * 1 <6> + 0 * 1 <5> + 1 * 1 <4> + 1 * 1 <3> + 1 * 1
<2> + 1 * 1 <1> + 1 * This corresponds approximately to the expression of 1 <0>.
[0082]
In the above-described example, the decimal number 5 is represented by a 7-bit thermometer
code. This is because seven bits are required to represent the maximum number 111 (7 in
decimal notation) that can be represented by a 3-bit binary code by a thermometer code.
Similarly, 255 bits are required to represent a number that can be represented by an 8-bit binary
code with a thermometer code.
[0083]
The output of the encoder 49 expressed by the thermometer code is supplied as a drive signal to
the driver circuit 9 at and the like. The individual drivers D1, D2,..., D4 shown in FIG. 8 are, for
example, 32-bit serial in / parallel out high breakdown voltage drivers. The driver D1 includes,
for example, a driver circuit 9at and a driver circuit 9ab. Similarly, driver D2 includes, for
example, driver circuit 9bt and driver circuit 9bb, driver D3 includes, for example, driver circuit
9ct and driver circuit 9cb, and driver D4 includes, for example, driver circuit 9dt and driver
circuit 9db. . As a matter of course, the drivers D1, D2, ..., D4 and the like may be disposed only
on one side of the upper side substrate or the lower side substrate.
[0084]
For the electrode formed on the lower substrate, which corresponds to one of the electrodes
formed on the upper substrate, an output opposite to that for the electrode formed on the upper
substrate is taken out. Ru. It is assumed that the thermometer code output from the encoder 49
is, for example, 0000 to 0011111 (5 in decimal notation). At this time, in the drivers D1, D2, ...,
D4, for example, five of the electrodes formed on the upper side substrate are set to a high
potential, and the diaphragms of the five electroacoustic transducers approach the upper side
04-05-2019
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substrate Be in the That is, the number of ?1? s in a certain thermometer code indicates the
number of electroacoustic transducers in which the diaphragm portion is brought close to the
upper substrate. Note that the number of ?0? s in a certain thermometer code indicates the
number of electroacoustic transducers in which the diaphragm portion is brought close to the
lower substrate.
[0085]
When the electroacoustic conversion system 1 is in operation, the individual diaphragm portions
Di are either in a state of approaching the upper substrate or in a state of approaching the lower
substrate.
[0086]
For example, it is assumed that the number of electro-acoustic transducers included in the
electro-acoustic transducer system 1 is 256 in all.
As an initial state, for example, of the 256 electroacoustic transducers, the diaphragm part of
128 electroacoustic transducers is brought close to the upper base material, and the diaphragm
parts of the remaining 128 electroacoustic transducers are It is in a state of approaching the
lower substrate.
[0087]
From the initial state, for example, when a thermometer code which is 130 in decimal notation is
output from the encoder 49, one of the diaphragm portions of the 128 electroacoustic
transducers which are brought close to the lower substrate Two change to the state which
approached the upper substrate.
[0088]
Next, it is assumed that a thermometer code that is 125 in decimal notation is output from the
encoder 49.
Then, five of the diaphragm portions of the 130 electro-acoustic transducers brought close to the
04-05-2019
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upper substrate change to a state approaching the lower substrate. That is, the number of
changed bits of the thermometer code corresponds to the number of electroacoustic transducers
to be driven before and after the change of the thermometer code.
[0089]
In this manner, electro-acoustic conversion is performed according to a change in a bit of the
thermometer code based on the drive signal represented by the thermometer code.
[0090]
Although FIG. 8 shows a configuration example in which the electro-acoustic conversion system
1 does not include the signal processing unit 41, the electro-acoustic conversion system 1 may
include the signal processing unit 41.
[0091]
Of the plurality of electroacoustic transducers, which one of the electroacoustic transducers is to
be driven can be set arbitrarily.
For example, it is also possible to equalize the operating time of the individual electroacoustic
transducers, or to select an electroacoustic transducer at a position where a delay corresponding
to a desired directivity occurs.
[0092]
By the way, in the digital speaker, the spatially synthesized result of the sound generated from
each of the electroacoustic transducers is the output from the electroacoustic transducer system.
Therefore, it is preferable that the acoustic characteristics of the individual electroacoustic
transducers are all equal.
[0093]
04-05-2019
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When driving a large number of electroacoustic transducers simultaneously, the difference
between the individual electroacoustic transducers can be canceled out, so that the acoustic
characteristics of the individual electroacoustic transducers can be allowed to have some
variation. However, when the number of electro-acoustic transducers to be driven is small, the
choice of which one of the plurality of electro-acoustic transducers is driven decreases sharply.
[0094]
According to the present disclosure, the opposing surface of the diaphragm portion in the upper
base member is convex with respect to the surface of the electrode formed in the upper base
member, so that the diaphragm portion and the electrode formed in the upper base member
Contact can be prevented. Similarly, since the opposing surface of the diaphragm portion in the
lower side substrate is convex with respect to the surface of the electrode formed in the lower
side substrate, the diaphragm portion and the electrode formed in the lower side substrate
Contact can be prevented. Furthermore, according to the present disclosure, the amplitude of the
diaphragm portion can be easily managed by adjusting the thickness of the upper spacer and the
lower spacer. That is, according to the present disclosure, it is possible to suppress the variation
in the maximum displacement of the diaphragm part between the electroacoustic transducers,
and to suppress the variation in the acoustic characteristics of the individual electroacoustic
transducers. Therefore, according to the present disclosure, the performance of the
electroacoustic conversion system can be improved.
[0095]
According to the present disclosure, since it is not necessary to manufacture an electro-acoustic
transducer as a so-called MEMS, an electro-acoustic transducer and an array-like electro-acoustic
transducer and an electro-acoustic conversion system can be manufactured without complicating
the process. . Therefore, it is also easier to manufacture a large-sized electroacoustic transducing
system compared to the case of MEMS without requiring an enormous amount of time or cost.
[0096]
??? Second Embodiment> [Schematic Configuration of Electro-Acoustic Transducer System]
FIG. 9A is a plan view showing a configuration example of an electro-acoustic transducer system
04-05-2019
27
according to a second embodiment. FIG. 9B is a side view of the electro-acoustic transducer
system shown in FIG. 9A. FIG. 10 is an exploded perspective view of the electro-acoustic
transducer system shown in FIGS. 9A and 9B.
[0097]
As shown in FIGS. 9B and 10, the electro-acoustic conversion system 51 according to the second
embodiment roughly includes an upper base 57t, an upper spacer 55t, a vibrating member 53, a
lower spacer 55b, and a lower base. A material 57b is stacked in order. In the first embodiment, a
configuration example has been shown in which a material having a small conductor resistance is
selected as the vibrating member 3. However, in the second embodiment, the first embodiment is
characterized in that the vibrating member 53 mainly comprises a resin material. It differs from
the embodiment. By selecting a resin material as the material forming the vibrating member 53,
the displacement of each diaphragm can be increased, and the sound pressure obtained from the
electroacoustic conversion system 51 can be increased.
[0098]
The electroacoustic conversion system 51 has a plurality of electroacoustic transducers.
Individual electro-acoustic transducers are constituted by members arranged on the upper and
lower sides of the diaphragm part and the diaphragm part with a part of the vibrating member
53 as a diaphragm part. The plurality of electroacoustic transducers are arranged, for example, in
correspondence with the grid points to constitute an array of electroacoustic transducers. Each of
the plurality of electrodes formed on the upper side substrate 57t and the driver circuits 59at,
59bt, 59ct and 59dt disposed on the upper side substrate are electrically made by the wiring
pattern 58Wt formed on the upper side substrate 57t. Connected Similarly, each of the plurality
of electrodes formed on the lower base 57b and the driver circuits 59ab, 59bb, 59cb and 59db
disposed on the lower base 57b are formed on the lower base 57b. It is electrically connected by
the wiring pattern 58Wb.
[0099]
Next, the upper base 57t and the lower base 57b, the upper spacer 55t and the lower spacer
55b, and the vibrating member 53 will be described in order with reference to FIGS. The electroacoustic conversion system 51 has a substantially symmetrical configuration with respect to the
04-05-2019
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vibrating member 53. The configuration of the lower base 57b is substantially the same as the
configuration of the upper base 57t, and the configuration of the lower spacer 55b is
substantially the same as the configuration of the upper spacer 55t. Furthermore, the driver
circuits 59 at, 59 bt, 59 ct and 59 dt can have the same configuration as the driver circuits 9 at,
9 bt, 9 ct and 9 dt according to the first embodiment. Therefore, in the following description, the
specific description of the configuration of lower base material 57b, the specific description of
the configuration of lower spacer 55b, and driver circuits 59at, 59bt, 59ct, 59dt, 59ab, 59bb,
59cb and 59db The specific description of is omitted.
[0100]
(Upper Base Material) The upper base material 57t has a function as a support of the vibrating
member 53, and constitutes the outer shape of the electroacoustic conversion system 51.
Although FIG. 9A, FIG. 9B, and FIG. 10 showed the structural example by which the shape of the
upper side base material 57t was made flat form, it is not restricted to this. Further, the outer
shape of the upper side base material 57t is not limited to the square.
[0101]
11A is an enlarged view of a portion Q1 in FIG. As shown in FIG. 11A, for example, a plurality of
electrode portions and a plurality of wiring portions are formed on the main surface of the upper
side base material. A wiring pattern 58Wt is configured by the plurality of electrode portions and
the plurality of wiring portions formed on the upper side base material.
[0102]
In FIG. 11A, a U portion surrounded by a broken line corresponds to one unit of the plurality of
electroacoustic transducers. Each electrode portion 58eti is formed corresponding to one of the
plurality of electroacoustic transducers, and each electrode portion 58eti is electrically connected
to the driver circuit by an individual wiring portion 58wti. Be done.
[0103]
04-05-2019
29
11B is an enlarged view of a portion U shown in FIG. 11A. FIG. 11C is an enlarged view of a
portion corresponding to the U portion shown in FIG. 11A in the surface of the upper base
material facing the upper spacer. 11C is an enlarged view of one main surface of the upper base
material, but since the configuration of the lower base material 57b is substantially the same as
the configuration of the upper base material 57t, FIG. 11C is shown in FIG. It corresponds to the
figure which expands and shows Q5 part.
[0104]
As shown in FIG. 11C, a plurality of main surfaces of the upper side base material 57t
corresponding to one of the plurality of electroacoustic transducers are also provided on the
main surface facing the vibrating member 53. The electrodes are formed.
[0105]
As shown in FIGS. 11B and 11C, a through hole pthi is formed at, for example, the center of each
electrode portion 58eti.
Among the main surfaces of the upper base material 57t, the electrode 56eti formed on the main
surface facing the vibrating member 53 is an electrode formed on the main surface opposite to
the main surface by the through holes pthi. It is electrically connected to the unit 58eti.
Therefore, the drive voltage from the driver circuit is applied to the electrode 56 eti formed on
the main surface facing the vibrating member 53 through the electrode portion 58 eti, the wiring
portion 58 wti and the through hole pthi.
[0106]
The vibration of air generated with the vibration of the vibrating member 53 described later is
transmitted to the outside through the through hole pthi. Therefore, it is preferable that the
diameter of the through hole be as large as possible. On the other hand, from the viewpoint of
increasing the driving force to the vibrating member 53 as much as possible, it is preferable that
the area of the electrode 56 eti formed on the main surface facing the vibrating member 53 be
large. In particular, it is preferable that the transmission of electrostatic force to the central
portion of the diaphragm portion be large.
04-05-2019
30
[0107]
Here, in the case of forming the through hole pthi at the center of the electrode portion 58eti, if
the diameter of the through hole pthi is reduced in order to prevent the electrostatic force acting
on the central portion of the diaphragm portion from being reduced, the flow of air is
interrupted. It will
[0108]
Therefore, in the configuration example shown in FIG. 11B, six through holes hht1i, hht2i, hht3i,
hht4i, hht5i and hht6i are provided so as to surround the through hole pthi formed at the center
of the electrode portion 58eti.
Six through holes hht1i, hht2i, hht3i, hht4i, hht5i and hht6i are arranged, for example, at
positions corresponding to the vertices of a regular hexagon centered on the through hole pthi.
11B and 11C, regions other than the electrode unit 58eti, the wiring unit 58wti, the electrode
56eti, the through hole pthi, and the through holes hht1i, hht2i, hht3i, hht4i, hht5i, and hht6i are
shaded.
[0109]
The diameter of the through holes pthi is, for example, about several mm or less, and the
diameters of the individual through holes hht1i, hht2i, hht3i, hht4i, hht5i, and hht6i are, for
example, about several mm or less.
[0110]
By forming the through hole in addition to the through hole, it is possible to reliably transmit the
vibration of the air generated along with the vibration of the vibrating member 53 to the outside
while ensuring the transmission of the electrostatic force to the central portion of the diaphragm
portion. it can.
[0111]
11B shows an example in which circular through holes and through holes are formed in each
electrode portion 58eti, but the number, position, shape, size and the like of the through holes
and through holes are limited to this. Absent.
04-05-2019
31
Also, for example, all the through holes may be through holes.
11B and 11C, the shape of the electrode 56eti formed on the main surface facing the vibrating
member 53 and the shape of the electrode portion 58eti formed on the main surface opposite to
the main surface are the same. Although the same example is shown, it is not limited to this.
[0112]
As a material which constitutes upper substrate 57t, for example, LTCC or MID can be used as in
the first embodiment. Alternatively, a printed circuit board can also be used as the upper
substrate 57t. For example, a paper phenol substrate in which a paper substrate is impregnated
with a phenol resin, a paper epoxy substrate in which a paper substrate is impregnated with an
epoxy resin, a glass composite substrate in which glass fiber is impregnated with an epoxy resin,
glass fibers And a glass epoxy substrate in which an epoxy resin is impregnated in a woven
fabric.
[0113]
The material constituting the upper base material 57t is not limited to this, and for example, a
resin material or glass may be used. Of course, the material forming the upper base 57t and the
material forming the lower base 57b may not be the same.
[0114]
As a material which comprises electrode part 58eti, wiring part 58wti, and electrode 56eti, the
material with small conductor resistance is preferable, for example, although copper, gold, silver,
aluminum, nickel, or these combination etc. can be mentioned, It is not limited.
[0115]
(Upper Spacer) FIG. 12A is an enlarged view of a portion Q2 in FIG.
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32
12A is an enlarged view of one main surface of the upper spacer 55t, but since the configuration
of the lower spacer 55b is substantially the same as the configuration of the upper spacer 55t,
FIG. 12A corresponds to the portion Q4 in FIG. This corresponds to the enlarged view.
[0116]
As shown in FIG. 12A, in the upper spacer 55t, a plurality of openings Ati are formed
corresponding to one of the plurality of electroacoustic transducers. In FIG. 12A, regions other
than the opening Ati are shown by hatching.
[0117]
The upper spacer 55t is a member for securing displacement in a direction toward the upper
base 57t of the vibrating member 53 described later. Therefore, the area of the individual
openings Ati is larger than the area of the individual electrodes 56 eti. The diameter of the
electrode 56 eti is, for example, several mm, while the diameter of the opening Ati is larger than
the diameter of the electrode 56 eti.
[0118]
As a material which comprises the upper side spacer 55t, the material excellent in electrical
insulation is preferable, for example, although resin material, glass, rubber etc. can be mentioned,
it is not restricted to these.
[0119]
(Vibration member) Drawing 12B is a mimetic dia
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