JP2013058889A - Electroacoustic transducer, array electroacoustic transducer apparatus, and electroacoustic transducer system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroacoustic transducer, an array electroacoustic transducer apparatus, and an electroacoustic transducer system which are manufactured without complicating the processes.SOLUTION: An electroacoustic transducer includes: a first spacer; a second spacer; a diaphragm having an outer peripheral part supported by the first spacer and the second spacer; a first base material where a first electrode is formed on at least a part of a main surface facing the diaphragm; and a second base material where a second electrode is formed on at least a part of a main surface facing the diaphragm. The facing surface of the first base material which faces the diaphragm is formed so as to protrude toward the diaphragm relative to a surface of the first electrode and the facing surface of the second base material which faces the diaphragm is formed so as to protrude toward the diaphragm relative to a surface of the second electrode.

Description

  The present disclosure relates to an electroacoustic transducer, an arrayed electroacoustic transducer, and an electroacoustic transducer system. In particular, the present disclosure relates to an electroacoustic transducer, an arrayed electroacoustic transducer, and an electroacoustic transducer system that generate a vibration by receiving a digital signal as input and reproduce sound and the like.

  Development of a digital speaker that plays back voice, music, and the like using data recorded by a digital method as an input is in progress.

  The digital speaker is configured as a group of a plurality of electroacoustic transducers, for example. Unlike an analog speaker that plays back sound or music by inputting an analog signal corresponding to the amplitude change of the audio signal, in an individual speaker, each electroacoustic transducer performs electroacoustic conversion corresponding to the bit of the input signal. I do.

  The sounds generated by the individual electroacoustic transducers are spatially synthesized, so that the data recorded by the digital method is perceived by us as voice or music. The sound generated by each electroacoustic transducer is, for example, a pulse sound, and a digital speaker has a feature that power consumption is small.

  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 a unary digital drive signal. For example, Patent Document 2 listed below discloses an audio electroacoustic transducer system integrated with a substrate on which an encoder or a decoder is formed. Further, for example, Patent Document 3 below discloses a driving method and a driving apparatus related to a plurality of arranged conversion elements.

JP 2001-016675 A Special table 2008-510378 gazette International Publication No. 2009/066290

  However, if a digital speaker is manufactured as a so-called MEMS, the process management becomes complicated, and a huge period and cost are required for developing the digital speaker.

  A digital speaker that can be manufactured without complicating the process is desired.

The first preferred embodiment of the present disclosure is:
The electroacoustic transducer includes a first spacer, a second spacer, a diaphragm, a first base material, and a second base material.
The outer periphery of the diaphragm is supported by the first spacer and the second spacer.
The first electrode is formed on at least a part of the main surface of the first base material facing the diaphragm.
A second electrode is formed on at least a part of the main surface of the second base material facing the diaphragm.
The surface of the first base material facing the diaphragm is convex with respect to the diaphragm rather than the surface of the first electrode.
The surface of the second base material facing the diaphragm is more convex than the surface of the second electrode.

A second preferred embodiment of the present disclosure is:
An arrayed electroacoustic transducer includes a first spacer, a second spacer, a diaphragm, a first base material, and a second base material.
In the diaphragm, a plurality of openings corresponding to the plurality of openings formed in the first spacer and a plurality of openings formed in the second spacer are independently vibrated. Supported by the second spacer and the second spacer.
An electrode is formed in each of a plurality of regions corresponding to a plurality of openings formed in the first spacer on the main surface facing the diaphragm of the first base material.
An electrode is formed in each of a plurality of regions corresponding to a plurality of openings formed in the second spacer on the main surface facing the diaphragm of the second substrate.
The array-like electroacoustic transducer includes a plurality of electroacoustic transducers each having a region that can be independently vibrated on the diaphragm.

A third preferred embodiment of the present disclosure is:
The electroacoustic conversion system includes a first spacer, a second spacer, a diaphragm, a first base, a second base, one or more top driver circuits, and one or more bottoms. And a driver circuit.
In the diaphragm, a plurality of openings corresponding to the plurality of openings formed in the first spacer and a plurality of openings formed in the second spacer are independently vibrated. Supported by the second spacer and the second spacer.
An electrode is formed in each of a plurality of regions corresponding to a plurality of openings formed in the first spacer on the main surface facing the diaphragm of the first base material.
An electrode is formed in each of a plurality of regions corresponding to a plurality of openings formed in the second spacer on the main surface facing the diaphragm of the second substrate.
The one or more upper surface side driver circuits are arranged on the main surface opposite to the main surface facing the diaphragm among the main surfaces of the first base material, and are formed on the first base material. Electrical connection with the other electrodes.
One or more bottom side driver circuits are arranged on the main surface opposite to the main surface facing the diaphragm among the main surfaces of the second base material, and are formed on the second base material. Electrical connection with the other electrodes.
In the electroacoustic conversion system, each region of the diaphragm that can be independently vibrated is used as a unit in accordance with a drive signal from one or more top driver circuits or one or more bottom driver circuits. A plurality of electroacoustic transducers to be driven are provided.

  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 base material and a second base material are respectively arranged outside the first spacer and the second spacer. Among the main surfaces of the first base material, a plurality of electrodes are arranged on the main surface facing the diaphragm corresponding to the plurality of openings provided in the first spacer. Among the main surfaces of the second substrate, a plurality of electrodes are arranged on the main surface facing the diaphragm corresponding to the plurality of openings provided in the second spacer.

  An electrode disposed on the first substrate, a first spacer, and one of regions corresponding to a plurality of openings provided in the first spacer and the second spacer in the diaphragm; One unit of the electroacoustic transducer is composed of the second spacer and the electrode disposed on the second base material. That is, one of the regions corresponding to the plurality of openings provided in the first spacer and the second spacer in the diaphragm functions as a diaphragm portion in one unit of the electroacoustic transducer. The vibrations of the individual diaphragm portions are independent of each other.

  The surface of the first substrate facing the diaphragm is more convex than the surface of the first electrode, and the surface of the second substrate facing the diaphragm is the surface of the second electrode. The surface is more convex than the surface. Therefore, the contact between the diaphragm portion and the electrode disposed on the first base material and the electrode disposed on the second base material is prevented. The amplitude of the diaphragm portion is managed by the thicknesses of the first spacer and the second spacer, and variation in the maximum displacement of the diaphragm portion between the electroacoustic transducers is suppressed.

  A single diaphragm is divided by a plurality of openings provided in the first spacer and the second spacer, thereby forming a plurality of diaphragm portions. Therefore, the arrayed electroacoustic transducer and electroacoustic transducer system of the present disclosure include an array of a plurality of electroacoustic transducers that are driven independently.

  In the present disclosure, it is not necessary to manufacture an electroacoustic transducer as a so-called MEMS. In addition, since a plurality of diaphragm parts are configured with a common diaphragm, the manufacturing process of the electroacoustic transducer, the arrayed electroacoustic transducer and the electroacoustic transducer system is not complicated.

  According to at least one embodiment, it is possible to provide an electroacoustic transducer, an arrayed electroacoustic transducer, and an electroacoustic transducer system that can be manufactured without complicating the process.

FIG. 1A is a plan view illustrating a configuration example of an electroacoustic conversion system according to the first embodiment. 1B is a side view of the electroacoustic conversion system shown in FIG. 1A. FIG. 2 is an exploded perspective view of the electroacoustic conversion system shown in FIGS. 1A and 1B. FIG. 3A is an enlarged view showing a P1 portion in FIG. FIG. 3B is an enlarged view showing a portion corresponding to the P1 portion shown in FIG. 2 on the surface of the upper base material facing the upper spacer. FIG. 3C is an enlarged view showing one of the plurality of electrodes in FIG. 3B and its peripheral portion. FIG. 4A is an enlarged view showing a P2 portion in FIG. FIG. 4B is an enlarged view showing a P3 portion in FIG. FIG. 4C is an enlarged view showing one of the plurality of diaphragm portions in FIG. 4B and its peripheral portion. FIG. 5A is a schematic view of the electroacoustic conversion system according to the first embodiment viewed from the upper base material side. FIG. 5B is a schematic diagram illustrating a unit of an electroacoustic transducer in the electroacoustic transducer system and the arrayed electroacoustic transducer. 6A is a schematic diagram showing a VIxz-VIxz cross section of FIG. 5B. 6B is a schematic diagram illustrating 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 illustrating an example of a specific configuration of the signal processing unit and the electroacoustic conversion system according to the embodiment of the present disclosure. FIG. 9A is a plan view illustrating a configuration example of an electroacoustic conversion system according to a second embodiment. 9B is a side view of the electroacoustic conversion system shown in FIG. 9A. 10 is an exploded perspective view of the electroacoustic conversion system shown in FIGS. 9A and 9B. FIG. 11A is an enlarged view showing a Q1 portion in FIG. FIG. 11B is an enlarged view of the U portion shown in FIG. 11A. FIG. 11C is an enlarged view of a portion corresponding to the U portion shown in FIG. 11A on the surface of the upper base material facing the upper spacer. FIG. 12A is an enlarged view showing a Q2 portion in FIG. FIG. 12B is a schematic diagram illustrating a cross section of a configuration example of the vibration member. FIG. 13A is a schematic view of the electroacoustic conversion system according to the second embodiment as viewed from the upper base material side. FIG. 13B is a schematic diagram illustrating one unit of an electroacoustic transducer in the electroacoustic transducer system and the arrayed electroacoustic transducer. 14A is a schematic diagram illustrating a cross section taken along line XIV-XIV in FIG. 13B. FIG. 14B is an XZ sectional view showing another configuration example of the electroacoustic transducer.

Hereinafter, embodiments of an electroacoustic transducer, an arrayed electroacoustic transducer, and an electroacoustic transducer system will be described. The description will be made in the following order.
<1. First Embodiment>
[Schematic configuration of electroacoustic conversion system]
(Upper substrate)
(Upper spacer)
(Vibration member)
(Driver circuit)
[Schematic configuration of arrayed electroacoustic transducer]
[Schematic configuration of electroacoustic transducer]
[Outline of operation of electroacoustic conversion system]
<2. Second Embodiment>
[Schematic configuration of electroacoustic conversion system]
(Upper substrate)
(Upper spacer)
(Vibration member)
[Schematic configuration of arrayed electroacoustic transducer]
[Schematic configuration of electroacoustic transducer]
<3. Modification>

  In addition, embodiment described below is a suitable specific example of an electroacoustic transducer, an array-like electroacoustic transducer, and an electroacoustic transducer system. In the following description, various technically preferable limitations are applied. Unless otherwise specified, the present disclosure is not limited to electroacoustic transducers, arrayed electroacoustic transducers, and electroacoustic transducer systems. Examples are not limited to the embodiments shown below.

<1. First Embodiment>
[Schematic configuration of electroacoustic conversion system]
FIG. 1A is a plan view illustrating a configuration example of an electroacoustic conversion system according to the first embodiment. 1B is a side view of the electroacoustic conversion system shown in FIG. 1A. FIG. 2 is an exploded perspective view of the electroacoustic conversion system shown in FIGS. 1A and 1B.

  As shown in FIGS. 1B and 2, the electroacoustic conversion system 1 according to the first embodiment is schematically composed of an upper base material 7t, an upper spacer 5t, a vibration member 3, a lower spacer 5b, and a lower base. It has a configuration in which the materials 7b are sequentially laminated. As shown in FIGS. 1A, 1B, and 2, for example, four driver circuits 9at, 9bt, 9ct, and 9dt are arranged on the upper base material 7t. Of the main surface of the upper substrate 7t, for example, the wiring pattern 8Wt is formed on the main surface exposed to the outside. The wiring pattern is composed of, for example, a set of electrode portions and wiring portions. The lower base material 7b also has the same configuration as the configuration example of the upper base material 7t shown in FIG. 1A. For example, on the lower base material 7b, for example, four driver circuits 9ab, 9bb, 9cb and 9db are arranged, and, for example, on the main surface exposed to the outside among the main surfaces of the lower base material 7b, wiring is performed. A pattern 8Wb is formed.

  The electroacoustic conversion system 1 has a plurality of electroacoustic transducers. Each electroacoustic transducer is composed of a diaphragm portion and members disposed above and below the diaphragm portion, with a part of the vibration member 3 being 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 material 7t, the upper spacer portion, the diaphragm portion, the lower spacer portion, and the lower base material. One unit of the electroacoustic transducer is constituted by one of the plurality of electrodes formed in 7b.

  The plurality of electroacoustic transducers are arranged so as to correspond to lattice points, for example, and constitute an arrayed electroacoustic transducer. Each of the plurality of electrodes formed on the upper base material 7t and the driver circuits 9at, 9bt, 9ct, and 9dt disposed on the upper base material are electrically connected by the wiring pattern 8Wt formed on the upper base material 7t. Connected. Similarly, each of the plurality of electrodes formed on the lower substrate 7b and driver circuits 9ab, 9bb, 9cb and 9db disposed on the lower substrate 7b are formed on the lower substrate 7b. The wiring pattern 8Wb is electrically connected. Accordingly, each electroacoustic transducer is driven by a driver circuit disposed on the upper base material 7t and the lower base material 7b.

  Next, the upper base material 7t and the lower base material 7b, the upper spacer 5t and the lower spacer 5b, the vibration member 3, and the driver circuits 9at, 9bt, 9ct, and 9dt will be described in order with reference to FIGS. Do. The electroacoustic conversion system 1 has a substantially symmetric configuration with respect to the vibration member 3. Accordingly, the lower base material 7b and the lower spacer 5b are arranged symmetrically with respect to the upper base material 7t and the upper spacer 5t with respect to the vibration member 3. Furthermore, the configuration of the lower base material 7b is substantially the same as the configuration of the upper base material 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, a specific description of the configuration of the lower base material 7b, a specific description of the configuration of the lower spacer 5b, and driver circuits 9ab, 9bb, 9cb disposed on the lower base material 7b and A detailed description of 9db is omitted.

(Upper substrate)
The upper base material 7t has a function as a support for the vibration member 3 and constitutes the outer shape of the electroacoustic conversion system 1. In FIG. 1A, FIG. 1B, and FIG. 2, although the example of a structure by which the shape of the upper side base material 7t was flat form was shown, it is not restricted to this. Further, the outer shape of the upper substrate 7t is not limited to a quadrangle.

  FIG. 3A is an enlarged view showing a P1 portion in FIG. In the following, when it becomes necessary to identify individual electroacoustic transducers or members corresponding to the individual electroacoustic transducers, these are appropriately identified by subscripts.

  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 base material. A wiring pattern 8Wt is configured by the plurality of electrode portions and the plurality of wiring portions formed on the upper base material.

In FIG. 3A, a U portion surrounded by a broken line corresponds to one unit among a plurality of electroacoustic transducers. Each electrode portion 8ET _i, are formed corresponding to each one of a plurality of electro-acoustic transducer, the individual electrode portions 8ET _i, the individual wiring portions 8 wt _i, below driver circuit And electrically connected.

For example, two through holes ht1 _i and ht2 _i are formed in each electrode portion 8et _i . The through holes ht1 _i and ht2 _i are air holes formed so that air can enter and exit with vibration of the vibration member 3 described later. Although FIG. 3A shows an example in which two circular through holes ht1 _i and ht2 _i are formed in each electrode portion 8et _i , the number, position, shape, size, etc. of the through holes are limited to this. Absent.

  FIG. 3B is an enlarged view showing a portion corresponding to the P1 portion 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 among a plurality of electroacoustic transducers. 3B is an enlarged view of one main surface of the upper base material. However, since the configuration of the lower base material 7b is substantially the same as the configuration of the upper base material 7t, FIG. Corresponds to an enlarged view of the P5 portion shown in FIG.

As shown in FIG. 3B, among the main surfaces of the upper base material 7 t, a plurality of electroacoustic transducers corresponding to each of the plurality of electroacoustic transducers are also provided on the main surface on the side facing the vibration member 3. Electrodes are formed. Of the main surface of the upper base material 7t, the electrode 6et _i formed on the main surface on the side facing the vibration member 3 is an electrode portion 8et _i formed on the main surface opposite to the main surface. Electrically connected. Accordingly, for the electrode 6Et _i formed on the main surface of the side facing the vibrating member 3, via the electrode portions 8ET _i and the wiring portion 8 wt _i, a driving voltage from the later-described driver circuit can be applied .

FIG. 3C is an enlarged view showing one of the plurality of electrodes in FIG. 3B and its peripheral portion. In FIG. 3C, regions other than the electrode 6et _i and the through holes ht1 _i and ht2 _i are shaded.

As shown in FIG. 3C, the electrode 6et _i has, for example, a shape (so-called dumbbell shape) in which two locations on the circumference are constricted toward the center. The surface of the electrode 6et _i is concave with respect to the surface of the upper substrate 7t facing the vibration member 3. That is, the dumbbell-shaped constricted portions CP1 _i and CP2 _i protrude toward the vibration member 3. The dumbbell-shaped constricted portions CP1 _i and CP2 _i function as a stopper for preventing contact between the vibration member 3 and the electrode 6et _i , as will be described later.

From the viewpoint of increasing the driving force to the vibration member 3 as much as possible, it is preferable that the area of the electrode 6et _i formed on the main surface on the side facing the vibration member 3 is large. On the other hand, from the viewpoint of increasing the area where wiring is possible, the area of the electrode portion 8et _i formed on the main surface on the side not facing the vibration member 3 is preferably small. Therefore, in FIGS. 3A to 3C, the shape of the electrode 6et _i formed on the main surface on the side facing the vibration member 3 and the electrode portion 8et _i formed on the main surface on the opposite side to the main surface. However, the shape of the electrode 6et _i and the electrode portion 8et _i is not limited to this.

  As a material constituting the 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 lower. Since the firing temperature of LTCC is as low as about 900 ° C. or less as compared with the case where no glass-based material is added, it is possible to fire a substrate on which a wiring pattern using copper or silver having a low conductor resistance is formed. . Therefore, for example, a laminated base material including a substrate on which a wiring pattern is formed can be baked, and the laminated base material on which the wiring pattern is formed can be used as the upper base material 7t.

  As the upper substrate 7t, for example, a circuit molded component called MID (Molded Interconnect Device) can be used. MID is a circuit molded part in which an electric circuit is formed on a resin structure, and has an advantage that it is environmentally friendly because an electric circuit can be formed only by plating or vapor deposition. By applying MID to the upper base material 7t, it becomes easy to make the upper base material 7t a base material on which a step is formed.

  The material constituting the upper base material 7t is not limited to this, and for example, a resin material or glass may be used. Of course, the material constituting the upper base material 7t and the material constituting the lower base material 7b may not be the same.

Electrode portion 8ET _i, as the material constituting the wiring section 8 wt _i and electrode 6Et _i, preferably material conductor resistance is small, for example, copper, gold, silver, aluminum, and the like nickel or combinations thereof Not limited to these. In view to avoid the manufacturing process as complicated, electrode portions 8ET _i, wiring portions 8 wt _i and electrode 6Et _i is preferably configured of the same material. Electrode portion 8ET _i, wiring portions 8 wt _i and electrode 6Et _i, for example, plating or vapor deposition, it can be formed by sputtering.

(Upper spacer)
FIG. 4A is an enlarged view showing a P2 portion in FIG. 4A is an enlarged view of one main surface of the upper spacer 5t. Since the configuration of the lower spacer 5b is substantially the same as the configuration of the upper spacer 5t, FIG. 4A shows the portion P4 in FIG. This also corresponds to an enlarged view.

As shown in FIG. 4A, the upper spacer 5t, one by one of a plurality of electro-acoustic transducer in response, a plurality of openings Ht _i are formed. Note that in Figure 4A, shows an area other than the opening Ht _i shaded.

The upper spacer 5t is a member for ensuring displacement in the direction toward the upper base material 7t in the vibration member 3 described later. Therefore, the area of each opening Ht _i is larger than the area of each electrode 6 et _i . Assuming a circle including the electrode 6et _i , the diameter of the circle is, for example, about several mm, whereas the diameter of the opening Ht _i is larger than the diameter of the circle. .

  The material constituting the upper spacer 5t is preferably a material excellent in electrical insulation, and examples thereof include, but are not limited to, a resin material, glass, rubber, and the like.

(Vibration member)
FIG. 4B is an enlarged view showing a P3 portion in FIG. The vibration member 3 is a diaphragm for generating air vibration in electroacoustic conversion.

As shown in FIG. 4B, a plurality of diaphragm portions D _i are arranged on the vibration member 3. The diaphragm portion D _i is disposed at a position corresponding to the plurality of openings Ht _i provided in the upper spacer 5t. Accordingly, the individual diaphragm portions D _i can be independently vibrated along a direction (Z-axis direction) perpendicular to the paper surface.

In the present disclosure, the diaphragm portions D _i in the individual electroacoustic transducers are arranged on a common member. Therefore, according to the present disclosure, an electroacoustic transducer, an arrayed electroacoustic transducer and an electroacoustic transducer system can be manufactured without complicating the process.

  The material constituting the vibration member 3 is preferably a material having a low conductor resistance, and examples thereof include a metal material. Examples of the metal material include stainless steel, titanium, aluminum, beryllium, magnesium, titanium boronate, and duralumin. Stainless steel is an alloy containing iron and chromium or nickel. The stainless steel can be appropriately selected from austenitic stainless steel, ferritic stainless steel, or martensitic stainless steel. SUS430, SUS440C, SUS420J2, SUS410S, etc. are suitable.

FIG. 4C is an enlarged view showing one of the plurality of diaphragm portions in FIG. 4B and its peripheral portion. When a metal material such as stainless steel is used as the material constituting the vibration member 3, for example, the shape D _i of each diaphragm portion is a vibration in order to increase the displacement of each diaphragm portion D _i as much as possible. It is preferable that the shape is easy to do. Specifically, for example, as shown in FIG. 4C, the outer peripheral portion of each diaphragm portion D _i, it is preferable that the slit is provided.

In the configuration example shown in FIG. 4C, four slits s1 _i , s2 _i , s3 _i, and s4 _i are formed in the outer peripheral portion of each diaphragm portion. That is, the central portion of the diaphragm portion D _i shown in FIG. 4C is supported by the four arm portions h1 _i , h2 _i , h3 _i, and h4 _i . In FIG. 4B and FIG. 4C, regions other than the slits are shown by shading.

Since the four arm portions h1 _i , h2 _i , h3 _i, and h4 _i function as cantilevers, the displacement of the central portion of the diaphragm portion D _i can be increased compared to the case where no slit is formed. 4C shows an example in which four slits s1 _i , s2 _i , s3 _i, and s4 _i are formed on the outer peripheral portion of each diaphragm portion D _i , the number, position, shape, and size of the slits are shown. This is not limited to this.

(Driver circuit)
The driver circuit is a circuit that supplies a current for driving each electroacoustic transducer, and is configured by a combination of transistors, for example. As shown in FIGS. 1A, 1B, and 2, for example, four driver circuits 9at, 9bt, 9ct, and 9dt are arranged on the upper base material 7t. The electrode 6et _i formed on the upper substrate 7t has an electrical connection with any of the driver circuits 9at, 9bt, 9ct, and 9dt disposed on the upper substrate 7t. Similarly, for example, four driver circuits 9ab, 9bb, 9cb and 9db are arranged on the lower base material 7b. Each of the plurality of electrodes formed on the lower base material 7b has an electrical connection with any of the driver circuits 9ab, 9bb, 9cb, and 9db arranged on the lower base material 7b.

For example, when the vibration member 3 is set to the ground potential, if the electrode 6et _i corresponding to a certain electroacoustic transducer among the plurality of electrodes formed on the upper base material 7t is set to a high potential, the electroacoustic conversion is performed. An electrostatic force acts on the diaphragm portion D _{i of the} container, and the diaphragm portion D _i approaches the upper substrate 7t. That is, displacement in the + Z direction of the diaphragm portion D _i of a certain one electro-acoustic transducer is controlled by a driver circuit disposed on the upper base member 7t. At this time, among the plurality of electrodes formed on the lower base material 7b, the electrode corresponding to the electroacoustic transducer is set to the ground potential.

Similarly, the displacement in the −Z direction in the diaphragm portion D _i of a certain electroacoustic transducer is controlled by a driver circuit disposed on the lower substrate 7b. Accordingly, each electroacoustic transducer is driven by a driver circuit disposed on the upper base material 7t and the lower base material 7b.

  As will be described later, the driver circuit supplies a driving current for bringing the diaphragm portion of the electroacoustic transducer closer to the upper base material or the lower base material according to the input signal. In addition, the manufacturer of the electroacoustic conversion system 1 can set suitably which electroacoustic transducer is driven among several electroacoustic transducers.

[Schematic configuration of arrayed electroacoustic transducer]
FIG. 5A is a schematic view of the electroacoustic conversion system according to the first embodiment viewed from the upper base material side. FIG. 5A is a diagram showing one main surface of the upper base material 7t. Since the configuration of the lower base material 7b is substantially the same as the configuration of the upper base material 7t, FIG. This also corresponds to a schematic view seen from the lower substrate 7b side.

  As shown in FIG. 5A, the plurality of electroacoustic transducers are arranged so as to correspond to lattice points, for example, and constitute an arrayed electroacoustic transducer 11. The number of the plurality of electroacoustic transducers in the arrayed electroacoustic transducer 11 can be arbitrarily set. Specifically, the number of the plurality of electroacoustic transducers in the array-like electroacoustic transducer 11 may be, for example, a power of 2 or 1 less than a power of 2. By setting the number of the plurality of electroacoustic transducers to a power of 2, for example, it is possible to prevent a circuit for generating a drive signal for the plurality of electroacoustic transducers from becoming complicated.

  Arrangement of a plurality of electroacoustic transducers can also be set arbitrarily. For example, a plurality of electroacoustic transducers can be arranged in a radial, concentric, polygonal, or elliptical shape.

  The outer shape of the array-like electroacoustic transducer 11 can also be set arbitrarily. For example, when the outer shape of the upper substrate 7t is a square shape, for example, the driver circuits 9at, 9bt, 9ct, and 9dt are arranged one by one on four sides of the square shape. At this time, a plurality of electroacoustic transducers can be divided into a plurality of groups, and a plurality of electroacoustic transducers belonging to each group can be associated with each of the driver circuits 9at, 9bt, 9ct, and 9dt. is there.

  For example, in FIG. 5A, a plurality of electroacoustic transducers are divided into four groups Ga, Gb, Gc and Gd, and a plurality of electroacoustic transducers belonging to the first group Ga, and a driver circuit 9at, The example of a structure connected by wiring pattern 8Wat is shown. In FIG. 5A, a plurality of electroacoustic transducers belonging to the second group Gb are indicated by circles represented by broken lines, a 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 electroacoustic transducers belonging to the second group Gb are connected to the driver circuit 9bt, the plurality of electroacoustic transducers belonging to the third group Gc are connected to the driver circuit 9ct, The plurality of electroacoustic transducers belonging to the fourth group Gd are connected to the driver circuit 9dt.

  As described above, by dividing a 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, the plurality of electroacoustic transducers are divided into a plurality of groups along a rectangular diagonal line, but the present invention is not limited to this example. The number and arrangement of driver circuits can also be set as appropriate according to the number and arrangement of a plurality of electroacoustic transducers.

[Schematic configuration of electroacoustic transducer]
FIG. 5B is a schematic diagram illustrating a unit of an electroacoustic transducer in the electroacoustic transducer system and the arrayed electroacoustic transducer. Specifically, the electroacoustic transducer T _i includes one of a plurality of electrodes formed on the upper base material 7t, an upper spacer portion St _i , a diaphragm portion D _i, and a lower spacer portion Sb _i. And one of a plurality of electrodes formed on the lower substrate 7b. In FIG. 5B, the electrode portion 8 et _i formed on the main surface of the upper base material 7 t that does not face the vibration member 3 and the main surface of the upper base material 7 t that faces the vibration member 3. The electrode 6et _i formed on the main surface on the side to be processed, the upper spacer part St _i, and the diaphragm part D _i are overlaid. In FIG. 5B, the electrode portion 8eb _i formed on the main surface on the side not facing the vibration member 3 in the main surface of the lower substrate 7b, and the vibration member 3 in the main surface of the lower substrate 7b. The illustration of the electrode 6eb _i and the lower spacer portion Sb _i formed on the opposing main surface is omitted. In FIG. 5B, the region other than the opening Ht _i of the upper spacer portion St _i is shown by shading.

6A is a schematic diagram showing a VIxz-VIxz cross section of FIG. 5B. 6B is a schematic diagram illustrating a VIyz-VIyz cross section of FIG. 5B. As shown in FIGS. 6A and 6B, the diaphragm portion D _i that is a part of the vibrating member 3 includes an upper spacer portion St _i that is a part of the upper spacer 5t and a lower spacer that is a part of the lower spacer 5b. It supported the outer peripheral portion by parts Sb _i.

The electrode 6Eb _i formed on the electrode 6Et _i or lower base member 7b is formed in the upper base member 7t, by the drive voltage corresponding to the audio signal input is given, the upper base member 7t and lower diaphragm portion D _i between the Gawamotozai 7b is displaced. A drive voltage from the driver circuit is applied to the electrode 6eb _i via the electrode portion 8eb _i and the wiring portion 8wb _i . In addition, since the outer peripheral part of the diaphragm part D _i is supported by the upper spacer part St _i and the lower spacer Sb _i , the displacement of the diaphragm part D _i in each electroacoustic transducer T _i is independent of each other. .

The thickness of the upper spacer part St _i and the lower spacer part Sb _i is, for example, about several μm. By adjusting the thickness of the upper spacer 5t and the lower spacer 5b, the amplitude of the diaphragm portion D _i can be easily managed. Note that the thickness of the diaphragm portion D _i is, for example, about several μm.

Displacement of the diaphragm portion D _i generates the air vibrations. Vibration of air caused by the displacement of the diaphragm portion D _i is the two formed in the electrode portions 8ET _i and two through holes formed in the electrode 6et _i ht1 _i and ht2 _i and electrode portions 8Eb _i and electrode 6Eb _i through It is transmitted to the outside through the holes hb1 _i and hb2 _i . Electroacoustic conversion in each electroacoustic transducer T _i is performed by transmitting the vibration of air accompanying the displacement of the diaphragm portion D _{i to} the outside. The diameters of the individual through holes ht1 _i , ht2 _i , hb1 _i and hb2 _i are, for example, about several mm or less.

As shown in FIG. 6A, in the upper substrate, portions PR1 _i and PR2 _i corresponding to the dumbbell-shaped constricted portions CP1 _i and CP2 _i shown in FIG. 3C are directed toward the central portion of the electroacoustic transducer T _i. It protrudes. Further, the surface of the upper base material 7t facing the diaphragm portion D _i is convex with respect to the surface of the electrode 6et _i . The thickness of the upper base material 7t is, for example, about several tens of μm. Between the surface of the upper base material 7t facing the diaphragm portion D _i and the surface of the electrode 6et _i , for example, about 1 μm to 100 μm. A gap is formed. That is, gp shown in FIG. 6B is about 1 μm to 100 μm. Similarly, the surface of the lower substrate 7b facing the diaphragm portion D _i is convex with respect to the surface of the electrode 6eb _i .

Since the surface of the upper base material 7t facing the diaphragm portion D _i is convex with respect to the surface of the electrode 6et _i formed on the upper base material 7t, it is formed on the diaphragm portion D _i and the upper base material 7t. Contact with the formed electrode 6et _i is prevented. Similarly, since the surface facing the diaphragm portion D _i of the lower substrate 7b is convex with respect to the surface of the electrode 6Eb _i formed on the lower base member 7b, and a diaphragm portion D _i, under Contact with the electrode 6eb _i formed on the side substrate 7b is prevented.

  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 diagram corresponding to FIG. 6B.

As shown in FIGS. 7A and 7B, the upper base material or the lower base material of the electroacoustic transducer T2 _i may be configured as a laminated base material. 7A and 7B, an example in which the upper base material 27t is formed as a laminated base material of the base material 27ta and the base material 27tb, and the lower base material 27b is formed as a laminated base material of the base material 27ba and the base material 27bb. Show. At this time, the thickness of the base material 27ta, the base material 27tb, the base material 27ba, and the base material 27bb is, for example, about several tens of μm.

When configuring the upper substrate or the lower substrate as a laminated substrate, for example, the electrode portion 28Et _i, electrodes 36Et _i, electrodes 36Eb _i, a through hole formed in the electrode portions 28Eb _i, through holes pt1 _i, It can be formed as pt2 _i , pb1 _i and pb2 _i . In the present specification, in the case of “through hole”, the method for forming the conductive layer on the inner wall of the hole is not limited to plating.

By using the upper base material 27t as a laminated base material, it becomes easy to make the upper base material 27t a base material on which a step is formed. The surface of the upper base material 27t facing the diaphragm portion D _i is convex with respect to the surface of the electrode 36et _i formed on the upper base material 27t, thereby forming the diaphragm portion D _i and the upper base material 27t. Contact with the electrode 36 et _i can be prevented. It is also possible to form a wiring pattern inside the upper base material and electrically connect the electrode facing the diaphragm portion and the wiring pattern formed inside the base material through a through hole. The lower base material 27b can have the same configuration as the upper base material 27t.

[Outline of operation of electroacoustic conversion system]
Next, an outline of the operation of the electroacoustic conversion system according to the embodiment will be described with reference to FIG.

  FIG. 8 is a block diagram illustrating an example of a specific configuration of the signal processing unit and the electroacoustic conversion system according to the 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 via the signal processing unit 41.

  Specifically, the signal processing unit 41 includes, for example, a preprocessing unit 43, an oversampling unit 45, a ΔΣ conversion unit 47, and an encoder 49, and is configured as an integrated circuit such as an FPGA (Field-Programmable Gate Array). Is done. An audio signal sent from a digital audio player or the like is input to the signal processing unit 41 via, for example, an optical digital input terminal 40 and an audio interface (Digital Audio Interface Receiver (DIR or DAI)) 42. .

  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 synthesis of the L channel signal and R channel signal, volume (gain) adjustment, equalization, and the like. Is given.

  Next, the preprocessed input signal is supplied to the oversampling unit 45. The oversampling unit 45 performs oversampling on the input signal. The sampling frequency of the input signal is 44.1 kHz or 48 kHz, and the oversampling ratio at this time is, for example, 8 times.

  The oversampled input signal is then supplied to the ΔΣ converter 47. In the ΔΣ conversion unit 47, ΔΣ modulation (also referred to as ΣΔ modulation) is applied to the input signal, and the quantization noise caused by the quantization error is quantized. Specifically, noise shaping is performed on the input signal to remove quantization noise distributed in a high frequency band by a digital low-pass filter. Thereafter, the decimation filter reduces the quantization word length to the target number of bits.

Here, the target number of bits is determined by the number of electroacoustic transducers included in the electroacoustic transducer system. For example, in the case of an electroacoustic transducer system in which 256 electroacoustic transducers T _{0 to} T ₂₅₅ are arranged, the quantization word length is reduced to 8 bits (2 ⁸ = 256) or less.

  The input signal with the quantized word length reduced is then supplied to the encoder 49. The output from the ΔΣ converter 47 is, for example, an 8-bit binary code. The encoder 49 converts an 8-bit binary code into a thermometer code.

  Here, the thermometer code is a code that uses two values “0” and “1” and expresses the value by the number of consecutive “1” s. In the expression by the thermometer code, the column “1” is switched from a certain bit to a column “0”. Such an expression is called a thermometer code because the switching of bits resembles the display of a thermometer.

For example, 5 expressed as a decimal number is expressed as 101 in a 3-bit binary code. On the other hand, 5 expressed as a decimal number is expressed as 0011111 when expressed by a thermometer code. This is almost corresponding to the fact that 5 expressed in decimal is expressed as 0 * 1 ⁶ + 0 * 1 ⁵ + 1 * 1 ⁴ + 1 * 1 ³ + 1 * 1 ² + 1 * 1 ¹ + 1 * 1 ⁰ Yes.

  In the above example, 5 expressed in decimal is expressed by a 7-bit thermometer code. This is because 7 bits are required to express the maximum number 111 (7 in decimal notation) that can be expressed by a 3-bit binary code as a thermometer code. Similarly, 255 bits are required to express a number that can be expressed by an 8-bit binary code by a thermometer code.

  The output of the encoder 49 expressed by the thermometer code is supplied as a drive signal to the driver circuit 9at. .., D4 are, for example, 32-bit serial-in / parallel-out high-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. . Of course, the drivers D1, D2,..., D4, etc. may be arranged only on either one of the upper substrate and the lower substrate.

  For an electrode formed on the lower substrate corresponding to one of the electrodes formed on the upper substrate, an output reversed from the output for the electrode formed on the upper substrate is taken out. The Assume that the thermometer code output from the encoder 49 is, for example, 0000... 0011111 (5 in decimal number). At this time, the drivers D1, D2,..., D4, for example, set five of the electrodes formed on the upper base material to a high potential, and the diaphragm portions of the five electroacoustic transducers approach the upper base material. State. That is, the number of “1” in a certain thermometer cord indicates the number of electroacoustic transducers in which the diaphragm portion is brought close to the upper base material. Note that the number of “0” in a certain thermometer cord indicates the number of electroacoustic transducers in which the diaphragm portion is brought close to the lower base material.

When the electroacoustic conversion system 1 is in an operating state, each diaphragm portion D _i is in a state of approaching the upper base material or a state of approaching the lower base material.

  For example, it is assumed that the total number of electroacoustic transducers included in the electroacoustic conversion system 1 is 256. As an initial state, for example, among 256 electroacoustic transducers, the diaphragm portions of 128 electroacoustic transducers are close to the upper base material, and the diaphragm portions of the remaining 128 electroacoustic transducers are It is in a state of approaching the lower base material.

  From the initial state, for example, when a thermometer code of 130 expressed in decimal number is output from the encoder 49, the diaphragm parts of the 128 electroacoustic transducers that are close to the lower base material Two change to the state which approached the upper side base material.

  Next, it is assumed that a thermometer code of 125 expressed in decimal is output from the encoder 49. Then, five of the 130 electroacoustic transducer diaphragm portions that are in the state of approaching the upper base material change to a state of approaching the lower base material. 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.

  Thus, based on the drive signal expressed by the thermometer code, electroacoustic conversion is performed according to the change of the bit of the thermometer code.

  In FIG. 8, the configuration example in which the electroacoustic conversion system 1 does not include the signal processing unit 41 is shown, but the electroacoustic conversion system 1 may include the signal processing unit 41.

  Which of the plurality of electroacoustic transducers is to be driven can be arbitrarily set. For example, it is possible to equalize the operating time of each electroacoustic transducer, or to select an electroacoustic transducer at a position where a delay corresponding to a desired directivity occurs.

  By the way, in a digital speaker, the result of spatially synthesizing sounds generated from individual electroacoustic transducers is an output from the electroacoustic conversion system. Therefore, it is preferable that the acoustic characteristics of the individual electroacoustic transducers are all equivalent.

  When a large number of electroacoustic transducers are driven at the same time, the difference between the individual electroacoustic transducers can be canceled out, so that some variation in the acoustic characteristics of the individual electroacoustic transducers can be allowed. However, when the number of electroacoustic transducers to be driven is small, the choice of which electroacoustic transducer to drive among a plurality of electroacoustic transducers is drastically reduced.

  According to the present disclosure, since the facing surface of the diaphragm portion in the upper base material is convex with respect to the surface of the electrode formed on the upper base material, the diaphragm portion and the electrode formed on the upper base material Contact can be prevented. Similarly, since the opposing surface of the diaphragm part in the lower base material is convex with respect to the surface of the electrode formed on the lower base material, the diaphragm part and the electrode formed on the lower base material Contact can be prevented. Furthermore, according to the present disclosure, the amplitude of the diaphragm portion can be easily managed by adjusting the thicknesses of the upper spacer and the lower spacer. That is, according to the present disclosure, variation in the maximum displacement of the diaphragm portion between the electroacoustic transducers can be suppressed, and variation in acoustic characteristics of the individual electroacoustic transducers can be suppressed. Therefore, according to the present disclosure, the performance of the electroacoustic conversion system can be improved.

  According to the present disclosure, since it is not necessary to manufacture an electroacoustic transducer as a so-called MEMS, an electroacoustic transducer, an arrayed electroacoustic transducer, and an electroacoustic transducer system can be manufactured without complicating the process. . Therefore, it becomes easy to manufacture a large electroacoustic conversion system as compared with the case of MEMS without requiring an enormous period and cost.

<2. Second Embodiment>
[Schematic configuration of electroacoustic conversion system]
FIG. 9A is a plan view illustrating a configuration example of an electroacoustic conversion system according to a second embodiment. 9B is a side view of the electroacoustic conversion system shown in FIG. 9A. 10 is an exploded perspective view of the electroacoustic conversion system shown in FIGS. 9A and 9B.

  As shown in FIGS. 9B and 10, the electroacoustic conversion system 51 according to the second embodiment schematically includes an upper base material 57t, an upper spacer 55t, a vibration member 53, a lower spacer 55b, and a lower base. The material 57b is laminated in order. In the first embodiment, a configuration example in which a material having a low conductor resistance is selected as the vibration member 3 has been described. However, in the second embodiment, the vibration member 53 is mainly made of a resin material. It is different from the embodiment. By selecting a resin material as the material constituting the vibration member 53, the displacement of each diaphragm portion can be increased, and the sound pressure obtained from the electroacoustic conversion system 51 can be increased.

  The electroacoustic transducer system 51 has a plurality of electroacoustic transducers. Each electroacoustic transducer is composed of a diaphragm portion and members disposed above and below the diaphragm portion, with a part of the vibrating member 53 as a diaphragm portion. The plurality of electroacoustic transducers are arranged so as to correspond to lattice points, for example, and constitute an arrayed electroacoustic transducer. Each of the plurality of electrodes formed on the upper base material 57t and the driver circuits 59at, 59bt, 59ct, and 59dt disposed on the upper base material are electrically connected by the wiring pattern 58Wt formed on the upper base material 57t. Connected. Similarly, each of the plurality of electrodes formed on the lower base material 57b and driver circuits 59ab, 59bb, 59cb and 59db disposed on the lower base material 57b are formed on the lower base material 57b. The wiring pattern 58Wb is electrically connected.

  Next, the upper base material 57t and the lower base material 57b, the upper spacer 55t and the lower spacer 55b, and the vibration member 53 will be described in order with reference to FIGS. The electroacoustic conversion system 51 has a substantially symmetric configuration with respect to the vibration member 53. The configuration of the lower base material 57b is substantially the same as the configuration of the upper base material 57t, and the configuration of the lower spacer 55b is substantially the same as the configuration of the upper spacer 55t. Further, the driver circuits 59at, 59bt, 59ct, and 59dt can have the same configuration as the driver circuits 9at, 9bt, 9ct, and 9dt according to the first embodiment. Therefore, in the following description, a specific description of the configuration of the lower substrate 57b, a specific description of the configuration of the lower spacer 55b, and driver circuits 59at, 59bt, 59ct, 59dt, 59ab, 59bb, 59cb and 59db. The detailed description of is omitted.

(Upper substrate)
The upper base material 57 t functions as a support for the vibration member 53 and constitutes the outer shape of the electroacoustic conversion system 51. 9A, 9B, and 10, the configuration example in which the shape of the upper base material 57t is a flat plate shape is shown, but the present invention is not limited to this. Further, the outer shape of the upper base material 57t is not limited to a quadrangle.

  FIG. 11A is an enlarged view showing a Q1 portion 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 base material. A wiring pattern 58Wt is constituted by a plurality of electrode portions and a plurality of wiring portions formed on the upper base material.

In FIG. 11A, a U portion surrounded by a broken line corresponds to one unit among a plurality of electroacoustic transducers. The individual electrode portions 58et _i are formed corresponding to one of the plurality of electroacoustic transducers, and the individual electrode portions 58et _i are electrically connected to the driver circuit and the electric circuit by the individual wiring portions 58wt _i. Connected.

  FIG. 11B is an enlarged view of the U portion shown in FIG. 11A. FIG. 11C is an enlarged view of a portion corresponding to the U portion shown in FIG. 11A on the surface of the upper base material facing the upper spacer. FIG. 11C is an enlarged view of one main surface of the upper base material. 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. This corresponds to an enlarged view of part Q5.

  As shown in FIG. 11C, among the main surfaces of the upper base material 57t, a plurality of electroacoustic transducers corresponding to each of the plurality of electroacoustic transducers are provided on the main surface on the side facing the vibration member 53. Electrodes are formed.

As shown in FIGS. 11B and 11C, a through hole pth _i is formed in the center of each electrode portion 58et _i , for example. Of the main surface of the upper base material 57t, the electrode 56et _i formed on the main surface facing the vibrating member 53 is formed on the main surface opposite to the main surface by the through hole pth _i. The electrode portion 58 et _i is electrically connected. Therefore, the drive voltage from the driver circuit is applied to the electrode 56 et _i formed on the main surface on the side facing the vibration member 53 via the electrode portion 58 et _i , the wiring portion 58 wt _i and the through hole pth _i. Applied.

The vibration of the air generated with the vibration of the vibration member 53 described later is transmitted to the outside through the through hole pth _i . Therefore, it is preferable that the diameter of the through hole is made as large as possible. On the other hand, from the viewpoint of increasing the driving force on the vibration member 53 as much as possible, it is preferable that the area of the electrode 56 et _i formed on the main surface on the side facing the vibration member 53 is large. In particular, it is preferable that the transmission of electrostatic force to the central portion of the diaphragm portion is large.

Here, when the through hole pth _i is formed in the center of the electrode portion 58 et _i , if the diameter of the through hole pth _i 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 Will be hindered.

Therefore, in the configuration example shown in FIG. 11B, so as to surround the through hole pth _i formed in the center of the electrode portion 58et _i, 6 one through hole _{hht1 i, hht2 i, hht3 i} , hht4 i, hht5 i and Hht6 _i is Is provided. The six through holes hht1 _i , ht2 _i , ht3 _i , ht4 _i , ht5 _i and hh6 _i are arranged at positions corresponding to the vertices of a regular hexagon centered on the through hole pth _i , for example. Note that in FIG. 11B and FIG. 11C, the electrode portions 58Et _i, wiring portions 58 wt _i, electrodes 56Et _i, through holes pth _i and the through hole _{hht1 i, hht2 i, hht3 i} , hht4 i, except Hht5 _i and Hht6 _i The area is shaded.

The diameter of the through hole pth _i is, for example, about several mm or less, and the diameters of the individual through holes hh1 _i , ht2 _i , ht3 _i , ht4 _i , ht5 _i, and ht6 _i are, for example, about several mm or less, respectively. Is done.

  By forming the through hole in addition to the through hole, it is possible to reliably transmit the air vibration generated due to the vibration of the vibration member 53 to the outside while ensuring the transmission of the electrostatic force to the central portion of the diaphragm portion. it can.

FIG. 11B shows an example in which circular through holes and through holes are formed in each electrode portion 58 et _i . However, the number, position, shape, size, and the like of through holes and through holes are not limited thereto. I can't. For example, all the through holes may be through holes. 11B and 11C, the shape of the electrode 56et _i formed on the main surface on the side facing the vibration member 53 and the shape of the electrode portion 58et _i formed on the main surface opposite to the main surface. However, the present invention is not limited to this.

  As a material constituting the upper base material 57t, for example, LTCC or MID can be used as in the first embodiment. Alternatively, a printed circuit board can be used as the upper base material 57t. Printed circuit boards include, for example, a paper phenol substrate in which a paper base material is impregnated with a phenol resin, a paper epoxy substrate in which a paper base material is impregnated with an epoxy resin, a glass composite substrate in which a glass fiber is impregnated with an epoxy resin, and a glass fiber. Examples thereof include a glass epoxy substrate in which an epoxy resin is impregnated into a cloth woven in (1).

  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 constituting the upper base material 57t and the material constituting the lower base material 57b may not be the same.

As a material constituting the electrode part 58et _i , the wiring part 58wt _i and the electrode 56et _i , a material having a low conductor resistance is preferable, and examples thereof include copper, gold, silver, aluminum, nickel or a combination thereof. Not limited to these.

(Upper spacer)
FIG. 12A is an enlarged view showing a Q2 portion in FIG. 12A is an enlarged view of one main surface of the upper spacer 55t. Since the configuration of the lower spacer 55b is substantially the same as the configuration of the upper spacer 55t, FIG. 12A shows the Q4 portion in FIG. This also corresponds to an enlarged view.

As shown in FIG. 12A, the upper spacer 55t has a plurality of openings At _i corresponding to one of the plurality of electroacoustic transducers. In FIG. 12A, the area other than the opening At _i is shown by shading.

The upper spacer 55t is a member for ensuring displacement in a direction toward the upper base material 57t in the vibration member 53 described later. Accordingly, the area of each opening At _i is larger than the area of each electrode 56 et _i . The diameter of the electrode 56 et _i is, for example, about several mm, while the diameter of the opening At _i is larger than the diameter of the electrode 56 et _i .

  The material constituting the upper spacer 55t is preferably a material excellent in electrical insulation, and examples thereof include, but are not limited to, a resin material, glass, rubber, and the like.

(Vibration member)
FIG. 12B is a schematic diagram illustrating a cross section of a configuration example of the vibration member. In the first embodiment, a configuration example in which a metal material such as stainless steel is used as the vibration member has been shown. However, in the second embodiment, the vibration member 53 is configured as a laminate of a resin material and a conductive material. Is done.

  As shown in FIG. 12B, the vibrating member 53 has a configuration in which a base material layer 53a, a conductive layer 53b, and an insulating layer 53c are sequentially stacked.

  The base material layer 53a is, for example, a film made of a resin material. By using a resin material for the base material layer 53a, the displacement of the vibration member 53 with respect to the electrostatic force applied to the vibration member 53 can be increased. Examples of the resin material constituting the base material layer 53a include polyphenylene sulfide (PPS), polyethylene terephthalate (PET), polycarbonate (Polycarbonate (PC)), and cycloolefin polymer (COP). ), Polyethersulphone (PES), polyethylene naphthalate (Polyethylenenaphthalate (PEN)), triacetylcellulose (TAC), polyimide (Polyimide), polymethylmethacrylate (PMMA), aramid ( Aramid (aromatic polyamide)).

  The conductive layer 53b is provided to set the potential of the vibration member 53 to, for example, a ground potential. Examples of the material constituting the conductive layer 53b include copper, gold, silver, aluminum, nickel, or a combination thereof. The conductive layer 53b is formed by vapor deposition, plating, sputtering, or the like using the base layer 53a as a support base. Specifically, the conductive layer 53b is, for example, a gold deposition layer.

The insulating layer 53c is a layer provided to prevent a short circuit between the conductive layer 53b and the electrode 56et _i formed on the upper base material 57t. Examples of the material constituting the insulating layer 53c include a resin material. Examples of the resin material include polyimide, polyphenylene sulfide, polyethylene terephthalate, polycarbonate, cycloolefin polymer, polyether sulfone, polyethylene naphthalate, triacetyl cellulose, polymethyl methacrylate, and aramid. For forming the insulating layer 53c, for example, micro gravure coating method, wire bar coating method, direct gravure coating method, die coating method, dipping method, spray coating method, reverse roll coating method, curtain coating method, comma coating method, knife coating A method such as spin coating or spin coating can be applied.

As shown in FIG. 12A, the upper spacer 55t has a plurality of openings At _i corresponding to one of the plurality of electroacoustic transducers. The distance between the centers of the adjacent openings is, for example, about several millimeters, and portions corresponding to the plurality of openings At _i provided in the upper spacer 55t in the vibration member 53 are individual electroacoustic transducers. It functions as a diaphragm part.

[Schematic configuration of arrayed electroacoustic transducer]
FIG. 13A is a schematic view of the electroacoustic conversion system according to the second embodiment as viewed from the upper base material side. FIG. 13A is a diagram showing one main surface of the upper base material 57t. Since the configuration of the lower base material 57b is substantially the same as the configuration of the upper base material 57t, FIG. 13A shows the electroacoustic conversion system 51. It corresponds also to the schematic seen from the lower base material 57b side.

  As shown in FIG. 13A, the plurality of electroacoustic transducers are arranged so as to correspond to lattice points, for example, and constitute an arrayed electroacoustic transducer 61. The number of the plurality of electroacoustic transducers in the arrayed electroacoustic transducer 61 can be arbitrarily set. Arrangement of a plurality of electroacoustic transducers can also be set arbitrarily. For example, a plurality of electroacoustic transducers can be arranged in a radial, concentric, polygonal, or elliptical shape.

  The outer shape of the array-like electroacoustic transducer 61 can also be set arbitrarily. For example, when the outer shape of the upper base material 57t is a square shape, for example, the driver circuits 59at, 59bt, 59ct, and 59dt are arranged one by one on four sides of the square shape. At this time, a plurality of electroacoustic transducers can be divided into a plurality of groups, and a plurality of electroacoustic transducers belonging to each group can be associated with each of the driver circuits 59at, 59bt, 59ct, and 59dt. is there.

  For example, in FIG. 13A, a plurality of electroacoustic transducers are divided into four groups Gra, Grab, Grc and Grd, and a plurality of electroacoustic transducers belonging to the first group Gra, and a driver circuit 59at, The example of a structure connected by wiring pattern 58Wat is shown. In FIG. 13A, a plurality of electroacoustic transducers belonging to the second group Grb are indicated by circles represented by broken lines, a plurality of electroacoustic transducers belonging to the third group Grc are indicated by black circles, and A plurality of electroacoustic transducers belonging to the fourth group Grd are indicated by shaded circles. For example, the plurality of electroacoustic transducers belonging to the second group Grb are connected to the driver circuit 59bt, the plurality of electroacoustic transducers belonging to the third group Grc are connected to the driver circuit 59ct, and The plurality of electroacoustic transducers belonging to the fourth group Grd are connected to the driver circuit 59dt.

  In FIG. 13A, the plurality of electroacoustic transducers are divided into a plurality of groups along a rectangular diagonal line, but the present invention is not limited to this example. The number and arrangement of driver circuits can also be set as appropriate according to the number and arrangement of a plurality of electroacoustic transducers.

[Schematic configuration of electroacoustic transducer]
FIG. 13B is a schematic diagram illustrating one unit of an electroacoustic transducer in the electroacoustic transducer system and the arrayed electroacoustic transducer. Specifically, the electroacoustic transducer T3 _i includes one of a plurality of electrodes formed on the upper base material 57t, an upper spacer portion S3t _i , a diaphragm portion D3 _i, and a lower spacer portion S3b _i. And one of a plurality of electrodes formed on the lower base material 57b. In FIG. 13B, the electrode portion 58et _i formed on the main surface of the upper base material 57t that does not face the vibration member 53 and the main surface of the upper base material 57t that faces the vibration member 53. The electrode 56et _i formed on the main surface on the side to be processed, the upper spacer portion S3t _i, and the diaphragm portion D3 _i are overlaid. In FIG. 13B, the region other than the opening portion At _i of the upper spacer portion S3t _i is shown by shading.

14A is a schematic diagram illustrating a cross section taken along line XIV-XIV in FIG. 13B. As shown in FIG. 14A, the diaphragm portion D3 _i that is a part of the vibrating member 53 includes an upper spacer portion S3t _i that is a part of the upper spacer 55t and a lower spacer portion S3b _i that is a part of the lower spacer 55b. The outer periphery is supported by. Since the outer peripheral portion of the diaphragm portion D3 _i is supported by the upper spacer portion S3t _i and the lower spacer portion S3b _i , the displacement of the diaphragm portion D3 _i in each electroacoustic transducer T3 _i is independent of each other.

The thickness of the upper spacer part S3t _i and the lower spacer part S3b _i is, for example, about several tens of μm. The thickness of the base material layer 53a, the conductive layer 53b, and the insulating layer 53c constituting the vibration member 53 is, for example, about several μm. The thickness of the diaphragm portion D3 _i is the sum of these values. In addition, the thickness of the upper base material 57t and the lower base material 57b is, for example, about 0.1 mm to 10 mm.

In the configuration example shown in FIG. 14A, the electrode portion 58et _i and the electrode 56et _i and the electrode portion 58eb _i and the electrode 56eb _i are configured by a laminate of a conductive layer 58a made of gold and a conductive layer 58c made of copper. The thickness of the stacked body of the conductive layers 58a and 58c is, for example, about several tens of μm. The distance d1 between the boundary between the opening At _i and the other region and the periphery of the electrode 56et _i is, for example, about several tens of μm. The distance d2 between the periphery of the electrode 56et _{i and} the periphery of the through hole is, for example, about 10 to 500 μm.

The displacement of the diaphragm portion D3 _i generates air vibrations. Vibration of air caused by the displacement of the diaphragm portion D3 _i is transmitted to the outside through the through hole and the through hole formed in the electrode portions 58Et _i and electrode 56Et _i and electrode portions 58Eb _i and electrode 56eb _i.

In a state where the diaphragm part D3 _i is not displaced, a gap of about several μm is provided between the surface of the diaphragm part D3 _{i and} the surface of the electrode 56et _i . In the first embodiment, since it is composed of a material vibrating member 3 is electrically conductive, the surface facing the diaphragm portion D _i of the upper base member 7t is a convex with respect to the surface of the electrode 6Et _i It had been. In the second embodiment, since the conductive layer 53b of the vibration member 53 is covered with the base material layer 53a and the insulating layer 53c, the diaphragm portion D3 _i and the electrode 56et _i formed on the upper base material 57t are provided. There is no short circuit when touched. Of course, as in the first embodiment, opposite the surface facing the diaphragm portion D3 _i in the upper base member 57t, and convex with respect to the surface of the electrode 56Et _i, the diaphragm D3 _i of the lower substrate 57b The surface may be convex with respect to the surface of the electrode 56eb _i .

FIG. 14B is an XZ sectional view showing another configuration example of the electroacoustic transducer. In the electroacoustic transducer T4 _i shown in FIG. 14B, the surface of the upper base material 67t facing the diaphragm portion D3 _i is convex with respect to the surface of the electrode 66et _i . In addition, the surface of the lower substrate 67b facing the diaphragm portion D3 _i is convex with respect to the surface of the electrode 66eb _i . By doing in this way, the variation of the maximum displacement of the diaphragm part between electroacoustic transducers is suppressed, and the variation of the acoustic characteristic of each electroacoustic transducer is suppressed.

<3. Modification>
The preferred embodiment has been described above, but the preferred specific example is not limited to the above description, and various modifications can be made.

  For example, the shape of the array-like electroacoustic transducer or electroacoustic transducer system may be a curved surface as a whole. The number, arrangement, and shape of the plurality of electroacoustic transducers in the arrayed electroacoustic transducer or electroacoustic transducer system can be arbitrarily set. Further, the number, arrangement, and shape of the through holes formed in the electrode can be arbitrarily set.

  The technology of the present disclosure can 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. Since the digital speaker has lower power consumption than the analog speaker, the technology of the present disclosure is particularly suitable for an in-vehicle speaker of an electric vehicle, for example. 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.

  The configurations, methods, shapes, materials, numerical values, and the like given in the above-described embodiments are merely examples, and different configurations, methods, shapes, materials, numerical values, and the like may be used as necessary. The configurations, methods, shapes, materials, numerical values, and the like of the above-described embodiments can be combined with each other without departing from the gist of the present disclosure.

For example, this indication can also take the following composition.
(1)
A first spacer;
A second spacer;
A diaphragm whose outer periphery is supported by the first spacer and the second spacer;
A first base material on which a first electrode is formed on at least a part of a main surface facing the diaphragm;
A second base material on which a second electrode is formed on at least a part of a main surface facing the diaphragm;
The surface of the first base material facing the diaphragm is convex with respect to the diaphragm rather than the surface of the first electrode.
An electroacoustic transducer in which a surface of the second base material facing the diaphragm is more convex than the surface of the second electrode.
(2)
The electroacoustic transducer according to (1), wherein the material constituting the diaphragm is a metal material.
(3)
The electroacoustic transducer according to (2), wherein the metal material is stainless steel.
(4)
The electroacoustic transducer according to (2) or (3), wherein a central portion of the diaphragm is supported by a plurality of arm portions formed between the outer peripheral portion and the central portion.
(5)
Any one of (1) to (4), wherein vibration of air generated by the displacement of the diaphragm propagates to the outside through an opening formed in the first electrode and the second electrode. The electroacoustic transducer described in 1.
(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 substrate;
A second wiring portion formed on the surface of the second base material,
The first electrode and the first wiring portion are electrically connected via at least one of the two or more openings formed in the first electrode;
(7) The second electrode and the second wiring portion are electrically connected via at least one of the two or more openings formed in the second electrode. Electroacoustic transducer.
(9)
The electroacoustic conversion according to any one of (1) to (8), wherein a material constituting at least one of the first base material and the second base material is a fired metal oxide. vessel.
(10)
The electroacoustic transducer according to any one of (1) to (8), wherein a material constituting at least one of the first base material and the second base material is a resin material.
(11)
A first spacer;
A second spacer;
A plurality of openings corresponding to the plurality of openings formed in the first spacer and a plurality of openings formed in the second spacer are independently vibrated, so that the first spacer A diaphragm supported by the spacer and the second spacer;
A first substrate on which electrodes are formed in each of a plurality of regions corresponding to the plurality of openings formed in the first spacer on the main surface facing the diaphragm;
A second base material on which electrodes are formed in each of a plurality of regions corresponding to the plurality of openings formed in the second spacer on the main surface facing the diaphragm;
An array-like electroacoustic transducer comprising a plurality of electroacoustic transducers each having a region that is independently vibrated in the diaphragm.
(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 corresponding to the plurality of openings formed in the first spacer and a plurality of openings formed in the second spacer are independently vibrated, so that the first spacer A diaphragm supported by the spacer and the second spacer;
A first substrate on which electrodes are formed in each of a plurality of regions corresponding to the plurality of openings formed in the first spacer on the main surface facing the diaphragm;
A second substrate on which electrodes are formed in each of a plurality of regions corresponding to the plurality of openings formed in the second spacer on the main surface facing the diaphragm;
Of the main surfaces of the first base material, an electrical contact with a plurality of electrodes disposed on the main surface opposite to the main surface facing the diaphragm and formed on the first base material One or more top side driver circuits having connections;
Of the main surfaces of the second base material, an electrical contact with a plurality of electrodes disposed on the main surface opposite to the main surface facing the diaphragm and formed on the second base material One or more bottom side driver circuits having connections,
Electricity that is independently driven in response to a drive signal from the one or more top-side driver circuits or the one or more bottom-side driver circuits, with each of the regions that can be independently vibrated in the diaphragm as a unit. An electroacoustic conversion system including a plurality of acoustic transducers.
(14)
The top side driver circuit and the bottom side driver circuit are each 2 or more,
The outer shape of the first substrate and the outer shape of the second substrate are rectangular,
The two or more upper-side driver circuits are disposed along a peripheral edge of the first substrate;
The electroacoustic conversion system according to (13), wherein the two or more bottom-side driver circuits are arranged along a peripheral edge of the second base material.
(15)
The plurality of electroacoustic transducers are divided into two or more groups;
One or more electroacoustic transducers belonging to each group are each a group of the top driver circuit corresponding to each group and the two or more bottom driver circuits among the two or more top driver circuits. The electroacoustic conversion system according to (14), which is driven by a bottom side driver circuit corresponding to.
(16)
The electroacoustic transducer system according to (15), wherein the plurality of electroacoustic transducers are arranged in a square shape corresponding to the lattice points, and are divided into two or more groups based on the diagonal line of the square shape. .

1, 51 ... Electroacoustic conversion system 3, 53 ... Vibration members 5t, 55t ... Upper spacers 5b, 55b ... Lower spacers 6et _i , 36et _i , 36eb _i ... Electrodes 7t, 27t 57t, 67t... Upper substrate 7b, 27b, 57b, 67b... Lower substrate 8Wt, 8Wb, 58Wt, 58Wb... Wiring pattern 9at, 9bt, 9ct, 9dt. 61 ... Array-like electroacoustic transducer 41 ... Signal processing unit 41
T _i , T 2 _i , T 3 _i , T 4 _i ... Electroacoustic transducers D _i , D 3 _i ... Diaphragm portion Ht _i , At _i ... Opening portion St _i , S 3 t _{i. i} , S3b _i ... Lower spacer portions h1 _i , h2 _i , h3 _i , h4 _i ... arm portions ht1 _i , ht2 _i ... through holes pt1 _i , pt2 _i , pb1 _i , pb2 _i.・ Through hole

Claims (16)

A first spacer;
A second spacer;
A diaphragm whose outer periphery is supported by the first spacer and the second spacer;
A first base material on which a first electrode is formed on at least a part of a main surface facing the diaphragm;
A second base material on which a second electrode is formed on at least a part of a main surface facing the diaphragm;
The surface of the first base material facing the diaphragm is convex with respect to the diaphragm rather than the surface of the first electrode.
An electroacoustic transducer in which a surface of the second base material facing the diaphragm is more convex than the surface of the second electrode.   The electroacoustic transducer according to claim 1, wherein a material constituting the diaphragm is a metal material.   The electroacoustic transducer according to claim 2, wherein the metal material is stainless steel.   The electroacoustic transducer according to claim 2, wherein a central portion of the diaphragm is supported by a plurality of arm portions formed between the outer peripheral portion and the central portion.   2. The electroacoustic transducer according to claim 1, wherein vibration of air generated by displacement of the diaphragm propagates to the outside through an opening formed in the first electrode and the second electrode.   The electroacoustic transducer according to claim 5, wherein the number of openings formed in the first electrode is two or more.   The electroacoustic transducer according to claim 6, wherein the number of openings formed in the second electrode is two or more. A first wiring portion formed on the surface of the first substrate;
A second wiring portion formed on the surface of the second base material,
The first electrode and the first wiring portion are electrically connected via at least one of the two or more openings formed in the first electrode;
The said 2nd electrode and the said 2nd wiring part are electrically connected through at least 1 of the said 2 or more opening part formed in the said 2nd electrode. Electroacoustic transducer.   The electroacoustic transducer according to claim 1, wherein a material constituting at least one of the first base and the second base is a fired metal oxide.   The electroacoustic transducer according to claim 1, wherein a material constituting at least one of the first base material and the second base material is a resin material. A first spacer;
A second spacer;
A plurality of openings corresponding to the plurality of openings formed in the first spacer and a plurality of openings formed in the second spacer are independently vibrated, so that the first spacer A diaphragm supported by the spacer and the second spacer;
A first substrate on which electrodes are formed in each of a plurality of regions corresponding to the plurality of openings formed in the first spacer on the main surface facing the diaphragm;
A second base material on which electrodes are formed in each of a plurality of regions corresponding to the plurality of openings formed in the second spacer on the main surface facing the diaphragm;
An array-like electroacoustic transducer comprising a plurality of electroacoustic transducers each having a region that is independently vibrated in the diaphragm.   The arrayed electroacoustic transducer according to claim 11, wherein the plurality of electroacoustic transducers are arranged corresponding to lattice points. A first spacer;
A second spacer;
A plurality of openings corresponding to the plurality of openings formed in the first spacer and a plurality of openings formed in the second spacer are independently vibrated, so that the first spacer A diaphragm supported by the spacer and the second spacer;
A first substrate on which electrodes are formed in each of a plurality of regions corresponding to the plurality of openings formed in the first spacer on the main surface facing the diaphragm;
A second substrate on which electrodes are formed in each of a plurality of regions corresponding to the plurality of openings formed in the second spacer on the main surface facing the diaphragm;
Of the main surfaces of the first base material, an electrical contact with a plurality of electrodes disposed on the main surface opposite to the main surface facing the diaphragm and formed on the first base material One or more top side driver circuits having connections;
Of the main surfaces of the second base material, an electrical contact with a plurality of electrodes disposed on the main surface opposite to the main surface facing the diaphragm and formed on the second base material One or more bottom side driver circuits having connections,
Electricity that is independently driven in response to a drive signal from the one or more top-side driver circuits or the one or more bottom-side driver circuits, with each of the regions that can be independently vibrated in the diaphragm as a unit. An electroacoustic conversion system including a plurality of acoustic transducers. The top side driver circuit and the bottom side driver circuit are each 2 or more,
The outer shape of the first substrate and the outer shape of the second substrate are rectangular,
The two or more upper-side driver circuits are disposed along a peripheral edge of the first substrate;
The electroacoustic conversion system according to claim 13, wherein the two or more bottom-side driver circuits are arranged along a peripheral edge of the second base material. The plurality of electroacoustic transducers are divided into two or more groups;
One or more electroacoustic transducers belonging to each group are each a group of the top driver circuit corresponding to each group and the two or more bottom driver circuits among the two or more top driver circuits. 15. The electroacoustic conversion system according to claim 14, wherein the electroacoustic conversion system is driven by a bottom side driver circuit corresponding to.   The electroacoustic transducer system according to claim 15, wherein the plurality of electroacoustic transducers are arranged in a quadrangular shape corresponding to the lattice points, and are divided into two or more groups based on the diagonal of the quadrangular shape. .

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