JP2015195420A - Audio device and audio system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an audio device from which a sound of small sound volume difference can be acquired over a wide range.SOLUTION: An audio device 10 includes a housing 20, a piezoelectric vibration unit 60 arranged in the housing 20 and having a piezoelectric element, and a communication unit for receiving an audio signal. While the load of the audio device 10 itself is applied to the piezoelectric vibration unit 60, the piezoelectric element is deformed by applying a received audio signal to cause deformation of the piezoelectric vibration unit 60, and the contact surface 200 of the audio device 10 is vibrated by deformation of the piezoelectric vibration unit 60 to generate a sound.

Description

  The present invention relates to an audio device and an audio system.

  Conventionally, various audio devices have been proposed for conducting audio conferences by connecting remote conference rooms via a communication network, for example (see Patent Document 1, for example). This type of audio device includes a microphone and a speaker, places the audio device on a table in a conference room, picks up the sound of the own room with a microphone, and sends it to the audio device (the other device) in the other conference room The received voice signal (voice of the other party's conference room) transmitted from the partner apparatus is output from the speaker. As the speaker, a dynamic speaker is mainly used.

JP 2008-245250 A

  However, since the conventional audio device uses a dynamic speaker, the speaker has low sound diffusibility, and the sound that can be heard decreases with distance from the speaker. For example, the sound of the speaker is difficult to hear depending on the positional relationship with the speaker. Become.

  Accordingly, an object of the present invention made in view of such a viewpoint is to provide an audio device and an audio system capable of acquiring audio with a small volume difference over a wide range.

An audio device according to the present invention that achieves the above object is as follows.
The body,
A piezoelectric vibration unit having a piezoelectric element disposed in the housing;
A communication unit for receiving an audio signal;
When the received voice signal is applied to the piezoelectric element in a state where the load of the sound device itself is applied to the piezoelectric vibration part, the piezoelectric element is deformed and the piezoelectric vibration part is deformed, and the piezoelectric vibration Due to the deformation of the part, the contact surface with which the sound device is in contact is vibrated to generate sound from the contact surface.

  The piezoelectric vibration unit may be disposed at a portion facing the contact surface of the housing.

It has a microphone that collects audio and outputs audio signals.
The communication unit may transmit an audio signal from the microphone.

  The microphone may be held by the housing via a damper that reduces vibration caused by deformation of the piezoelectric vibrating portion.

  The vibration direction of the piezoelectric element and the vibration direction of the diaphragm of the microphone may cross each other.

  The microphone may be arranged separately from the housing.

  The communication unit may receive the audio signal from another audio device.

A speaker that is arranged in the housing and that amplifies the received voice signal;
A detection unit for detecting a contact state between the contact surface and the piezoelectric vibration unit;
A control unit that controls the speaker and the piezoelectric vibration unit based on the contact state detected by the detection unit may be further included.

  The piezoelectric element is a multilayer piezoelectric element, and may be elastically deformed along the stacking direction.

  The piezoelectric vibration unit may include a covering member that transmits vibration due to deformation of the piezoelectric element to the contact surface to vibrate the contact surface.

  The contact surface may be a mounting surface on which the audio device is mounted.

Furthermore, an audio system according to the present invention that achieves the above object is
An audio system including a microphone unit and a speaker unit,
The microphone unit includes a microphone that collects sound and outputs an audio signal, and a transmission unit that transmits the audio signal to the speaker unit.
The speaker unit includes a housing, a piezoelectric vibration unit having a piezoelectric element disposed in the housing, and a receiving unit that receives the audio signal.
In a state where the load of the sound device itself is applied to the piezoelectric vibration part, the piezoelectric element is deformed by applying the sound signal to the piezoelectric element, and the piezoelectric vibration part is deformed. Due to the deformation, the contact surface in contact with the sound device is vibrated to generate sound from the contact surface.

  ADVANTAGE OF THE INVENTION According to this invention, the audio | voice apparatus which can acquire an audio | voice with a small volume difference over a wide range can be provided.

It is the external appearance perspective view and side view of the audio apparatus which concern on 1st Embodiment. It is explanatory drawing of a piezoelectric vibration part and its holding | maintenance part. It is a figure which shows the structure of a lamination type piezoelectric element. It is a figure which shows the modification of a lamination type piezoelectric element. It is a partial expanded sectional view of a piezoelectric vibration part. It is a functional block diagram of the principal part of an audio | voice apparatus. It is a functional block diagram which shows the structure of an example of a piezoelectric element drive part. It is a figure which shows an example of the frequency characteristic of LPF. It is a figure which shows an example of arrangement | positioning of a piezoelectric vibration part and a leg part. It is explanatory drawing of the sound generation operation | movement by an audio | voice apparatus. It is a figure which shows the other example of arrangement | positioning of a piezoelectric vibration part and a leg part. It is a figure which shows one structural example of an audio conference system provided with the audio | voice apparatus of FIG. It is a perspective view which shows schematic structure of the audio | voice apparatus which concerns on 2nd Embodiment. It is a perspective view which shows schematic structure of the audio | voice apparatus which concerns on 3rd Embodiment. It is a perspective view which shows the modification of 3rd Embodiment. It is a perspective view which shows schematic structure of the audio | voice apparatus which concerns on 4th Embodiment. It is a functional block diagram of the principal part of the audio | voice apparatus of FIG. It is a flowchart which shows an example of operation | movement of the audio | voice apparatus of FIG. It is a perspective view which shows schematic structure of the audio | voice system which concerns on 5th Embodiment. It is a functional block diagram of the principal part of the audio | voice system of FIG. It is a figure which shows the three modifications of the holding | maintenance aspect of a piezoelectric vibration part. It is a figure which shows schematic structure of the principal part which shows the modification of a piezoelectric vibration part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
1A and 1B are a perspective view and a side view showing a schematic configuration of an audio device according to the first embodiment of the present invention. The audio device 10 according to the present embodiment includes a housing 20 having a shape that can be placed on a table 200 installed in a conference room. In FIG. 1, the housing 20 has a substantially disk shape in FIG. 1, but can have any outer shape as long as it can be placed on the table 200. Here, the table 200 is an example of a contact surface with which the audio device 10 contacts. Therefore, in the following description, the table 200 is also referred to as a placement surface 200 or a contact surface 200. In the case 20, the operation unit 30 and the microphone 40 are disposed on the upper surface 20a side, and the foot 50 and the piezoelectric vibration unit 60 are disposed on the bottom surface 20b side.

  The operation unit 30 includes a known key such as a dial key for inputting a destination telephone number for performing a conference call, an operation key 31 such as a function key, and a known display unit 32 such as a liquid crystal display for displaying input information by the operation key 31. ing. The microphone 40 collects voices of surrounding conference participants and outputs a transmitted voice signal, and is constituted by a known microphone such as a condenser microphone or a dynamic microphone. In the present embodiment, the microphone 40 is held by the housing 20 via a damper 70 made of, for example, rubber rubber. The foot 50 is made of, for example, an elastic member such as rubber, silicone, or polyurethane, and a plurality of feet 50 are provided on the bottom surface 20 b to support the housing 20 on the table 200 together with the piezoelectric vibrating portion 60.

  FIG. 2 is an explanatory diagram of the piezoelectric vibrating portion 60 and its holding portion. The piezoelectric vibrating portion 60 is housed and held in a holding portion 100 formed in the housing 20 as shown in a partial cross section of the bottom portion of the housing 20 in FIG. That is, the piezoelectric vibration unit 60 is disposed at a portion of the housing 20 that faces the contact surface 200. The holding unit 100 includes a slit 101 having a uniform width that opens in the bottom surface 20b of the housing 20 and extends in the vertical direction in a state where the housing 20 is placed on a horizontal plane.

  As shown in an exploded view in FIG. 2, the piezoelectric vibration unit 60 includes a piezoelectric element 61, an O-ring 62, and an insulating cap 63 that is a covering member. A piezoelectric element is an element that expands or contracts or bends according to an electromechanical coupling coefficient of a constituent material by applying an electric signal (voltage). These elements are made of, for example, ceramic or quartz. The piezoelectric element may be a unimorph, bimorph or multilayer piezoelectric element. The multilayer piezoelectric element includes a multilayer bimorph element in which bimorphs are laminated (for example, about 8 to 40 layers), a plurality of dielectric layers made of, for example, PZT (lead zirconate titanate), and the plurality of dielectric layers. There is a stack type composed of a laminated structure with electrode layers arranged between body layers. A unimorph expands and contracts when an electric signal is applied, a bimorph bends when an electric signal is applied, and a stack type stacked piezoelectric element expands and contracts along the stacking direction when an electric signal is applied.

  In the present embodiment, the piezoelectric element 61 is formed of a stack type stacked piezoelectric element. The laminated piezoelectric element 61 includes, for example, a dielectric 61a made of ceramics such as PZT and an internal electrode having a comb-like cross section, as shown in the enlarged cross-sectional view and plan view in FIGS. 61b are alternately stacked. The internal electrode 61b is formed by alternately laminating the electrode connected to the first side electrode 61c and the electrode connected to the second side electrode 61d, and electrically connects the first side electrode 61c or the second side electrode 61d, respectively. Connected to.

  The laminated piezoelectric element 61 shown in FIGS. 3A and 3B has, on one end face, a first lead connection portion 61e electrically connected to the first side surface electrode 61c and a second side surface electrode 61d. An electrically connected second lead connecting portion 61f is formed. A first lead wire 61g and a second lead wire 61h are connected to the first lead connecting portion 61e and the second lead connecting portion 61f, respectively. In addition, the first side electrode 61c, the second side electrode 61d, the first lead connection portion 61e, and the second lead connection portion 61f are connected to the first lead connection portion 61e and the second lead connection portion 61f, respectively. 61g and the second lead wire 61h are connected and covered with an insulating layer 61i.

  The stacked piezoelectric element 61 has a length in the stacking direction of, for example, 5 mm to 120 mm. Moreover, the cross-sectional shape in the direction orthogonal to the stacking direction of the multilayer piezoelectric element 61 can be, for example, a substantially square shape of 2 mm square to 10 mm square or an arbitrary shape other than the square shape. Note that the number of laminated piezoelectric elements 61 and the cross-sectional area of the stacked piezoelectric element 61 can ensure sufficient sound pressure or sound quality of sound generated from a contact surface such as a table with which the piezoelectric vibrating unit 60 contacts according to the weight of the audio device 10. It is determined as appropriate.

  As will be described later, the stacked piezoelectric element 61 is supplied with a received voice signal from the control unit via the piezoelectric element driving unit. In other words, a voltage corresponding to the audio signal is applied to the multilayer piezoelectric element 61 from the control unit via the piezoelectric element driving unit. When the voltage applied from the control unit is an AC voltage, when a positive voltage is applied to the first side electrode 61c, a negative voltage is applied to the second side electrode 61d. Conversely, when a negative voltage is applied to the first side electrode 61c, a positive voltage is applied to the second side electrode 61d. When a voltage is applied to the first side electrode 61c and the second side electrode 61d, polarization occurs in the dielectric 61a, and the stacked piezoelectric element 61 expands and contracts from a state where no voltage is applied. The direction of expansion and contraction of the stacked piezoelectric element 61 is substantially along the stacking direction of the dielectric 61a and the internal electrode 61b. Alternatively, the expansion / contraction direction of the multilayer piezoelectric element 61 substantially coincides with the lamination direction of the dielectric 61a and the internal electrode 61b. Since the laminated piezoelectric element 61 expands and contracts substantially along the stacking direction, there is an advantage that the vibration transmission efficiency in the stretching direction is good.

  The present inventor has conceived that such a laminated piezoelectric element 61 is effective as a vibration element for generating a received voice from the contact surface 200 where the audio device 10 contacts a table or the like.

  3A and 3B, the first side electrode 61c and the second side electrode 61d are alternately connected to the internal electrode 61b, and are connected to the first lead connection portion 61e and the second lead connection portion 61f. It can also be a through-hole connected to each other. 3 (a) and 3 (b), the first lead connecting portion 61e and the second lead connecting portion 61f are formed of a first side electrode 61c and a first side electrode 61c at one end of the multilayer piezoelectric element 61, as shown in FIG. You may form in the 2nd side electrode 61d.

  As shown in the partial enlarged cross-sectional view of FIG. 5, the laminated piezoelectric element 61 has one end side surface having the first lead connection portion 61 e and the second lead connection portion 61 f in the slit 101 of the holding portion 100 of the housing 20. It is fixed via an adhesive 102 (for example, epoxy resin). Further, a cap 63 is inserted into the other end portion of the multilayer piezoelectric element 61 and is fixed by the adhesive 102.

  The cap 63 is formed of a material that can reliably transmit the expansion and contraction vibration caused by the laminated piezoelectric element 61 to a mounting surface (contact surface) such as a table, for example, hard plastic. When it is desired to suppress the mounting surface from being damaged, the cap 63 may not be a hard plastic but may be a relatively soft plastic. The cap 63 is formed with an entry portion 63 a located in the slit 101 and a projection 63 b protruding from the housing 20 in a state of being attached to the multilayer piezoelectric element 61, and located in the slit 101. An O-ring 62 is disposed on the outer periphery of the entry portion 63a. The O-ring 62 is made of, for example, silicone rubber. The O-ring 62 is used to move and hold the multilayer piezoelectric element 61 and at the same time makes it difficult for moisture or dust to enter the slit 101. The protrusion 63b has a hemispherical tip. The tip of the protruding portion 63b is not limited to a hemispherical shape, but has a shape that can reliably make point contact or surface contact with a mounting surface (contact surface) such as a table and transmit expansion and contraction vibration by the stacked piezoelectric element 61. Any shape can be used. In the state in which the piezoelectric vibrating portion 60 is attached to the holding portion 100, the protruding portion 63 b of the cap 63 protrudes from the bottom surface 20 b of the housing 20. Further, the protruding portion 63 b of the cap 63 has a facing surface 63 c that is a surface facing the bottom surface 20 b of the housing 20. As shown in FIG. 5, the opposing surface 63c is separated from the bottom surface 20b by a length d in a state where no voltage is applied to the multilayer piezoelectric element 61 and the multilayer piezoelectric element 61 does not expand or contract.

  FIG. 6 is a functional block diagram of a main part of the audio device 10 according to the present embodiment. The audio device 10 includes a communication unit 110, a piezoelectric element driving unit 120, and a control unit 130 in addition to the operation key 31, the display unit 32, the microphone 40, and the stacked piezoelectric element 61 described above. The operation key 31, the display unit 32, the microphone 40, and the communication unit 110 are connected to the control unit 130. The stacked piezoelectric element 61 is connected to the control unit 130 via the piezoelectric element driving unit 120.

  The communication unit 110 is connected to a communication network such as a public telephone line or an IP network by a communication cable such as a telephone line, an Ethernet cable, or by radio. The control unit 130 is a processor that controls the overall operation of the audio device 10. The control unit 130 applies a voice signal (for example, a voltage corresponding to the voice signal of the communication partner) received by the communication unit 110 via the piezoelectric element driving unit 120 to the stacked piezoelectric element 61.

  The piezoelectric element driving unit 120 includes a signal processing circuit 121, a booster circuit 122, and a low-pass filter (LPF) 123, for example, as shown in FIG. The signal processing circuit 121 is configured by, for example, a digital signal processor (DSP) having an equalizer, an A / D conversion circuit, and the like, and the digital signal from the control circuit 130 is required for equalization processing, D / A conversion processing, and the like. The signal processing is performed to generate an analog audio signal, which is output to the booster circuit 122. Note that the function of the signal processing circuit 121 may be incorporated in the control circuit 130.

  The booster circuit 122 boosts the voltage of the input analog audio signal and applies it to the multilayer piezoelectric element 61 via the LPF 123. Here, the maximum voltage of the audio signal applied to the laminated piezoelectric element 61 by the booster circuit 122 can be, for example, 10 Vpp to 50 Vpp, but is not limited to this range, and the weight of the audio device 10 and the laminated piezoelectric element are not limited thereto. It can be suitably adjusted according to the performance of 61. Note that the audio signal applied to the multilayer piezoelectric element 61 may be biased with a DC voltage, and a maximum voltage may be set around the bias voltage.

  In addition to the multilayer piezoelectric element 61, the piezoelectric element generally has higher power loss at higher frequencies. Therefore, the LPF 123 has a frequency characteristic that attenuates or cuts at least part of a frequency component of about 10 kHz to 50 kHz or more, or gradually. Alternatively, it is set to have a frequency characteristic in which the attenuation rate increases stepwise. FIG. 8 shows, as an example, the frequency characteristics of the LPF 123 when the cutoff frequency is about 20 kHz. Thus, by attenuating or cutting the high-frequency component, power consumption can be suppressed and heat generation of the multilayer piezoelectric element 61 can be suppressed.

  Next, an example of the arrangement of the piezoelectric vibrating portion 60 and the foot portion 50 will be described. FIG. 9 shows a state in which the audio device 10 is placed on a horizontal placement surface 200 such as a table with the bottom surface 20b side down. Here, the table is an example of a contacted member of the audio device 10, and the mounting surface 200 is an example of a contact surface (mounting surface) with which the audio device 10 comes into contact. In the arrangement example shown in FIG. 9, the piezoelectric vibrating portion 60 is arranged at the peripheral portion of the bottom surface 20 b, and the audio device 10 is placed on the placement surface 200 together with a plurality of feet 50 similarly arranged at the peripheral portion of the bottom surface 20 b. The case where it supports by many points (for example, 4 points) is shown. A point G indicates the center of gravity of the audio device 10.

  In FIG. 9, the foot portion 50 has a lowermost end portion 501. The lowermost end portion 501 is a portion of the foot portion 50 that comes into contact with the placement surface 200 when the audio device 10 is placed on a horizontal placement surface 200 such as a table with the bottom surface 20b side down.

  The piezoelectric vibration part 60 has a lowermost end part 601. The lowermost end portion 601 is a portion of the piezoelectric vibrating portion 60 that comes into contact with the placement surface 200 when the audio device 10 is placed on a horizontal placement surface 200 such as a table with the bottom surface 20b side down. . The lowermost end 601 is, for example, the tip of the cap 63.

  The audio device 10 has a lowermost end portion 101. The lowermost end portion 101 is assumed that the piezoelectric vibrating portion 60 does not exist when the audio device 10 is placed on a horizontal placement surface 200 such as a table with the bottom surface 20b down. In this case, it is a place that comes into contact with the mounting surface 200. The lowermost end 101 of the audio device 10 is, for example, an edge of the housing 20, but is not limited thereto. When the bottom surface 20 b is provided with a protruding portion that protrudes from the bottom surface 20 b, the protruding portion may be the lowermost end portion 101 of the audio device 10.

  9, the dotted line L passes through the center of gravity G of the audio device 10 and is perpendicular to the mounting surface 200 when the audio device 10 is mounted on a horizontal mounting surface 200 such as a table with the bottom surface 20b down. A straight line (virtual line). The alternate long and short dash line I is a line (virtual line) parallel to the mounting surface 200 passing through the lowermost end 101 and the dotted line L, which is in contact with the mounting surface 200 when it is assumed that the piezoelectric vibrating portion 60 does not exist. is there.

  In FIG. 9, a region R <b> 1 is a region on one side of the audio device 10 that is delimited by a dotted line L. The region R2 is a region on the other side of the audio device 10 that is delimited by a dotted line L. The foot 50 is provided on the bottom surface 20b on the region R1 side. Moreover, the piezoelectric vibration part 60 shall be provided in the area | region R2 side in the bottom face 20b.

  In this case, the piezoelectric vibrating portion 60 is preferably provided at a position as close as possible to the dotted line L on the region R2 side of the bottom surface 20b. As a result, the load applied to the piezoelectric vibrating portion 60 becomes larger than when the piezoelectric vibrating portion 60 is provided at a position separated from the dotted line L on the region R2 side of the bottom surface 20b.

  The foot 50 is preferably provided at a position as far as possible from the dotted line L on the region R1 side of the bottom surface 20b. Thereby, even when the piezoelectric vibrating portion 60 is provided at a position as close as possible to the dotted line L, a sufficient distance between the foot portion 50 and the piezoelectric vibrating portion 60 is ensured, and the sound device 10 is stably mounted. It can be mounted on.

  The lowest end portion 601 of the piezoelectric vibrating portion 60 is a one-dot chain line I when a voltage is not applied to the laminated piezoelectric element 61 and the laminated piezoelectric element 61 extends most from a state where it does not expand or contract or when the laminated piezoelectric element 61 has a maximum amplitude. It is better to be positioned closer to the mounting surface 200 side. That is, the lowermost end portion 601 is placed more than the alternate long and short dash line I when no voltage is applied to the multilayer piezoelectric element 61 and the multilayer piezoelectric element 61 extends most from a state where it does not expand or contract or when the multilayer piezoelectric element 61 has the maximum amplitude. It is good to protrude to the mounting surface 200 side. Thereby, the mounting surface 200 can be appropriately vibrated by the piezoelectric vibrating portion 60.

  The lowermost end 601 of the piezoelectric vibration unit 60 is applied when the laminated piezoelectric element 61 is contracted most from the state in which no voltage is applied to the laminated piezoelectric element 61 and the laminated piezoelectric element 61 does not expand or contract, or the laminated piezoelectric element 61. It is good to be located in the mounting surface 200 side rather than the dashed-dotted line I at the time of the minimum amplitude. That is, the lowest end portion 601 is one point at the time when the multilayer piezoelectric element 61 is at the minimum amplitude when the multilayer piezoelectric element 61 contracts the most from the state in which the voltage is not applied to the multilayer piezoelectric element 61 and the multilayer piezoelectric element 61 does not expand and contract. It is good to protrude from the chain line I to the mounting surface 200 side. Thereby, the lowermost end portion 101 of the audio device 10 is less likely to come into contact with the placement surface 200. For example, depending on the type of coating of the housing 20, the coating is difficult to peel off. Further, abnormal noise is less likely to occur between the lowermost end portion 101 and the placement surface 200.

  10A, 10B, and 10C are explanatory diagrams of the sound generation operation by the audio device 10 according to the present embodiment. As shown in FIG. 10A, the audio device 10 has the bottom surface 20b side of the housing 20 facing downward, and the cap 63 and the foot portion 50 of the piezoelectric vibration unit 60 are placed on a mounting surface (contact surface) 200 such as a table. Is placed in contact with the Thereby, the weight of the audio device 10 is given to the piezoelectric vibration unit 60 as a load. In the state shown in FIG. 10A, the stacked piezoelectric element 61 does not expand and contract because no voltage is applied.

  In this state, when the multilayer piezoelectric element 61 of the piezoelectric vibration unit 60 is driven by an audio signal, one or a plurality of multilayer piezoelectric elements 61 are provided as shown in FIGS. 10B and 10C. The cap 63 does not move away from the placement surface (contact surface) 200, but expands and contracts in response to an audio signal, with the contact portion of the individual foot 50 to the placement surface (contact surface) 200 as a fulcrum. If there is no inconvenience such as the lower end 101 contacting the placement surface 200 and generating abnormal noise, the lower end 101 may be slightly separated. The difference between the length of the laminated piezoelectric element 61 when it is most expanded and the length when it is most contracted is, for example, 0.05 μm to 50 μm. As a result, the expansion and contraction vibration of the multilayer piezoelectric element 61 is transmitted to the mounting surface 200 through the cap 63 to vibrate the mounting surface 200, and the mounting surface 200 functions as a vibration speaker and generates sound from the mounting surface 200. To do. In addition, if the difference between the length when stretched most and the length when shrunk most is less than 0.05 μm, there is a possibility that the mounting surface cannot be vibrated properly. Therefore, there is a risk that the sound device 10 may rattle.

  Here, as described above, the tip of the cap 63 may be positioned closer to the mounting surface 200 than the one-dot chain line I in FIG. 9 when the multilayer piezoelectric element 61 is extended most. Further, the tip of the cap 63 may be positioned closer to the placement surface 200 than the one-dot chain line I when the multilayer piezoelectric element 61 is contracted most.

  Further, the distance d between the bottom surface 20b and the facing surface 63c of the cap 63 shown in FIG. 5 is the state where the voltage is not applied to the multilayer piezoelectric element 61 and the multilayer piezoelectric element 61 is contracted most from the state where the multilayer piezoelectric element 61 does not expand and contract. It is better to be longer than the amount of displacement when This makes it difficult for the bottom surface 20b of the housing 20 and the cap 63 to come into contact with each other even when the multilayer piezoelectric element 61 is contracted most (the state shown in FIG. 10C). Therefore, it becomes difficult for the cap 63 to fall off the piezoelectric element 61.

  The arrangement location on the bottom surface 20b of the piezoelectric element portion 60, the length of the stacked piezoelectric element 61 in the stacking direction, the size of the cap 63, and the like are appropriately determined so as to satisfy the above-described conditions.

  Next, another example of the arrangement of the piezoelectric vibrating portion 60 and the foot portion 50 will be described with reference to FIG. In the arrangement example shown in FIG. 11, when a plurality (three or more) of foot portions 50 are provided on the peripheral edge of the bottom surface 20b of the housing 20, and the audio device 20 is placed on the horizontal plane at the center of the bottom surface 20b. In addition, the piezoelectric vibrating portion 60 is arranged on a vertical line passing through the center of gravity G. Therefore, when the number of the foot portions 50 is four, the audio device 10 is supported on the placement surface 200 at five points of the four foot portions 50 and the one piezoelectric vibrating portion 60.

  In FIG. 11, the dotted line L passes through the center of gravity G of the audio device 10 when the audio device 10 is placed on a horizontal placement surface 200 such as a table with the bottom surface 20 b side down, as in FIG. 9. This is a line (virtual line) perpendicular to the mounting surface 200. In FIG. 11, pairs of legs 50 are provided on both sides of the dotted line L passing through the dotted line L. Accordingly, in this case, four or more even number of the foot portions 50 are provided. Here, the dotted line L <b> 1 is a line (virtual line) that passes through the paired foot portions 50 and is perpendicular to the placement surface 200. The dotted line L2 is a line (virtual line) that passes through the paired foot 50 and is perpendicular to the placement surface 200. The dotted line L1 is separated from the dotted line L by a length D1 in the horizontal direction. The dotted line L2 is separated from the dotted line L by a length D2 in the horizontal direction.

  In FIG. 11, a region R <b> 1 is a region on one side delimited by a dotted line L. The region R2 is a region on the other side delimited by the dotted line L. The foot 50 on one side is disposed on the bottom surface 20b on the region R1 side with a distance D1 in the horizontal direction from the piezoelectric vibrating portion 60. The other leg portion 50 is arranged on the bottom surface 20b on the region R2 side, spaced apart from the piezoelectric vibrating portion 60 by a length D2 in the horizontal direction.

  The piezoelectric vibrating portion 60 is provided on the dotted line L on the bottom surface 20b. That is, the piezoelectric vibration unit 60 passes through the center of gravity G of the audio device 10 and is perpendicular to the mounting surface 200 when the audio device 10 is mounted on a horizontal mounting surface 200 such as a table with the bottom surface 20b side down. Placed on a straight line. Thereby, the weight of the audio device 10 can be applied to the piezoelectric vibration unit 60 as a load, and the expansion and contraction vibration of the piezoelectric vibration unit 60 can be efficiently transmitted to the placement surface (contact surface) 200. When D1 = D2, that is, when the two legs 50 forming a pair are provided at symmetrical positions in the horizontal direction across the piezoelectric vibrating part 60, the audio device 10 is stably placed on the placement surface 200. Can be placed.

  When the stacked piezoelectric element 61 is driven by an audio signal, the piezoelectric vibrating unit 60 vibrates and expands according to the audio signal without the cap 63 being separated from the placement surface (contact surface) 200. In addition, if there is no inconvenience such as abnormal noise generated when the lower end portion of the foot portion 50 comes into contact with the placement surface 200, the lower end portion of the foot portion 50 is slightly moved away from the placement surface 200 by driving the piezoelectric vibrating portion 60. It may be separated.

  When the audio device 10 is placed on a horizontal placement surface 200 such as a table with the bottom surface 20b down, the foot 50 is elastically deformed by the weight of the audio device 10 being applied as a load. That is, the foot portion 50 contracts in a direction perpendicular to the placement surface 200 due to the weight of the audio device 10. The amount of elastic deformation of the foot 50 in a state in which no voltage is applied to the multilayer piezoelectric element 61 and the multilayer piezoelectric element 61 does not expand and contract is the maximum when the voltage of the multilayer piezoelectric element 61 is not expanded and contracted. It is good that it is larger than the displacement amount. Thereby, when the laminated piezoelectric element 61 is extended most, the foot portion 50 is less likely to be separated from the placement surface 200, and the audio device 10 is stably placed on the placement surface 200.

  FIG. 12 is a diagram illustrating a configuration example of an audio conference system (audio system) including the audio device 10 according to the present embodiment. The audio device 10 is connected to the audio device 10 of a remote conference partner via a communication network 300 such as a public telephone line or an IP network. Note that each audio device 10 and the communication network 300 are connected by a communication cable such as a telephone line, an Ethernet cable, or by radio. Then, a transmission voice signal from the own voice device 10 is transmitted to the conference partner voice device 10, and a voice signal from the conference partner voice device 10 is a contact surface such as a table on which the own voice device 10 is placed. The audio conference is executed. Of course, the audio device of the conference partner may have a conventional configuration.

  According to the audio device 10 according to the present embodiment, since the piezoelectric element is used as a vibration source, the device can be reduced in size and weight as compared with a conventional audio device including a dynamic speaker. In addition, since the sound is output by vibrating the contact surface of the table or the like on which the sound device 10 is placed, it is possible to output sound with a uniform volume without directivity regardless of the distance from the device, and in a wide range of conference rooms. It is possible to obtain uniform and good audio characteristics. Therefore, it is not necessary to increase the sound around the main body as compared with a conventional audio device including a dynamic speaker. Further, since the microphone 40 is held by the housing 20 via the damper 70, the vibration of the piezoelectric vibrating portion 60 transmitted to the microphone 40 can be effectively attenuated. Therefore, sound sneaking into the microphone 40 can be reduced, and noise such as echo can be reduced.

  In addition, a stack type stacked piezoelectric element 61 is used as the piezoelectric element, and the expansion and contraction vibration is transmitted along the stacking direction by an audio signal, and the expansion and contraction vibration is transmitted to the mounting surface (contact surface) 200. The vibration transmission efficiency in the expansion / contraction direction (deformation direction) with respect to the (contact surface) 200 is good, and the placement surface (contact surface) 200 can be vibrated efficiently. In addition, since the multilayer piezoelectric element 61 is brought into contact with the mounting surface (contact surface) 200 via the cap 63, the multilayer piezoelectric element 61 can be prevented from being damaged. Further, since the weight of the audio device 10 is applied to the cap 63 as a load, the cap 63 is securely brought into contact with the placement surface (contact surface) 200, and the expansion / contraction vibration of the piezoelectric vibrating portion 60 is placed on the placement surface (contact surface) 200. Can be transmitted efficiently.

(Second Embodiment)
FIG. 13 is a perspective view showing a schematic configuration of an audio device according to the second embodiment of the present invention. The audio device 11 according to the present embodiment is the audio device 10 according to the first embodiment, in which a plurality of microphones 40 are arranged on the side surface 20c of the housing 20 (FIG. 13 is in four orthogonal directions). It is. The microphone 40 has a casing in which the vibration direction (indicated by a double arrow A) of the diaphragm constituting the microphone 40 intersects with the vibration direction (indicated by a double arrow B) of the piezoelectric vibrating portion 60 and is preferably orthogonal. 20 on the side surface 20c. The microphone 40 may be directly attached to the housing 20 or may be attached to the housing 20 via a damper as in the first embodiment. Since other configurations are the same as those of the first embodiment, the same components are denoted by the same reference numerals, and description thereof is omitted.

  According to the present embodiment, since the vibration direction A of the diaphragm of the microphone 40 intersects the vibration direction B of the piezoelectric vibration part 60, the vibration of the piezoelectric vibration part 60 transmitted to the microphone 40 can be more effectively performed. Can be attenuated. Therefore, sound sneaking into the microphone 40 can be made smaller, and noise such as echo can be made smaller. In particular, if the microphone 40 is held in the housing 20 via a damper, the effect becomes more remarkable.

(Third embodiment)
FIG. 14 is a perspective view showing a schematic configuration of an audio device according to the third embodiment of the present invention. The audio device 12 according to the present embodiment is obtained by separating the plurality of microphones 40 from the casing 20 of the apparatus body in the audio device 11 according to the second embodiment. Since other configurations are the same as those of the second embodiment, the same components are denoted by the same reference numerals, and description thereof is omitted. The microphone 40 is connected to the control unit 130 (see FIG. 6) disposed in the housing 20 via the cable 41 or wirelessly. The microphone 40 may be used by being placed on a contact surface such as a table on which the housing 20 is placed, or may be used by being attached to a conference participant like a pin microphone.

  As described above, if the microphone 40 is separated from the apparatus main body, the microphone 40 can be disposed in the vicinity of the conference participant, so that the transmitted voice can be efficiently converted into an electric signal without increasing the microphone sensitivity. Become. Therefore, it is possible to reduce the wraparound of the output received voice to the microphone 40 and to reduce noise such as echo. In addition, when the microphone 40 is used by being placed on a contact surface such as a table on which the casing 20 is placed, as shown in FIG. It is preferable to provide a plurality of foot portions 42 made of the same elastic member. In this way, the vibration of the contact surface transmitted to the microphone 40 by the foot portion 42 can be attenuated, so that the sound wraparound to the microphone 40 can be reduced and noise such as echo can be reduced.

(Fourth embodiment)
FIG. 16 is a perspective view showing a schematic configuration of an audio device according to the fourth embodiment of the present invention. The audio device 13 according to the present embodiment further includes a speaker 80 and a detection unit 90 in the audio device 11 according to the second embodiment. Since other configurations are the same as those of the second embodiment, the same components are denoted by the same reference numerals, and description thereof is omitted. The speaker 80 is a sound output device that outputs an audio signal, and includes, for example, a small dynamic speaker, a piezoelectric speaker, a capacitor speaker, and the like that have excellent frequency characteristics in a high sound range. The speaker 80 is provided in the housing 20 so as to output a received voice from the upper surface 20a of the housing 20.

  The detection unit 90 is provided on the bottom surface 20 b side of the housing 20, and whether or not the piezoelectric vibration unit 60 is in contact with the placement surface 200, that is, between the placement surface (contact surface) 200 and the piezoelectric vibration unit 60. Detect contact status. The detection unit 90 is configured by a device that can detect a contact state between the piezoelectric vibration unit 60 and the mounting surface 200, such as an infrared sensor, an ultrasonic sensor, a proximity sensor, a mechanical switch, a camera, and a pressure sensor. Further, the piezoelectric vibration unit 60 can be configured as the detection unit 90 by using the output of the piezoelectric vibration unit 60 as a sensor. The speaker 80 and the detection unit 90 are connected to the control unit 130 as shown in the functional block diagram of FIG.

  FIG. 18 is a flowchart showing an example of the operation of the audio device 13 according to the present embodiment. First, the control unit 130 confirms the presence or absence of an audio signal (step S101). When there is no audio signal (in the case of No), the control unit 130 ends this flow without applying a sound signal to the multilayer piezoelectric element 61 and the speaker 80. When there is an audio signal (in the case of Yes), the control unit 130 outputs the audio signal to the speaker 80 (step S102).

  Next, the control unit 130 confirms whether or not the detection unit 90 detects contact between the piezoelectric vibration unit 60 and the placement surface 200 (step S103). When the detection unit 90 does not detect contact between the piezoelectric vibrating unit 60 and the mounting surface 200 (in the case of No), the control unit 130 does not output an audio signal to the stacked piezoelectric element 61. Therefore, in this case, no reception voice is generated from the placement surface 200 and the reception voice is output only from the speaker 80.

  On the other hand, when the detection unit 90 detects the contact between the piezoelectric vibration unit 60 and the mounting surface 200 (in the case of Yes), the control unit 130 is stacked via the piezoelectric element driving unit 120 (see FIG. 6). An audio signal is output to the piezoelectric element 61 (step S104). Therefore, in this case, the received voice is generated from both the speaker 80 and the placement surface 200. The control unit 130 controls the audio signal output to the speaker 80 and the piezoelectric element 61 based on the contact state between the piezoelectric vibrating unit 60 and the mounting surface 200 by repeating the series of operations in FIG.

  In this way, when the piezoelectric vibration unit 60 is in contact with the placement surface 200, if the sound signal is output from both the placement surface 200 and the speaker 80, the speaker 80 has excellent frequency characteristics in the high sound range, Since the mounting surface 200 is relatively excellent in frequency characteristics in the low sound range, it is possible to output a sound having excellent frequency characteristics from the low sound range to the high sound range as a whole. Further, since the speaker 80 having excellent frequency characteristics in the high sound range can be small, the entire apparatus can be reduced in size and weight.

  In the present embodiment, when the piezoelectric vibrating portion 60 is in contact with the placement surface 200, audio signals are output from both the placement surface 200 and the speaker 80. An audio signal may be output only from Further, in the case of outputting an audio signal from both the mounting surface 200 and the speaker 80, the frequency of the audio signal applied to the speaker 80 so as to detect the output sound from the mounting surface 200 and correct the frequency characteristic thereof. The characteristics may be controlled, or the frequency characteristics of the audio signal applied to the laminated piezoelectric element 61 may be corrected so as to correct the frequency characteristics of the speaker 80.

(Fifth embodiment)
FIG. 19 is a perspective view showing a schematic configuration of an audio system according to the fifth embodiment of the present invention. The audio system according to the present embodiment includes a microphone unit 45 and an audio device 14 that are separated from each other. The audio device 14 constitutes a speaker unit, and includes a housing 20 and a piezoelectric vibration unit 60 held by the housing 20. The piezoelectric vibration unit 60 has the same configuration as that of the above-described embodiment, and is similarly held by the housing 20.

  FIG. 20 is a functional block diagram of the main part of the audio system according to the present embodiment. The microphone unit 45 includes a microphone 46 that collects sound and outputs an audio signal, and a transmission unit 47 that wirelessly transmits the audio signal from the microphone 46. The audio device 14 includes a receiving unit 150 that receives an audio signal wirelessly transmitted from the transmitting unit 47 of the microphone unit 45, a piezoelectric element driving unit 120 that drives the stacked piezoelectric element 61 that constitutes the piezoelectric vibrating unit 60, and a control. Unit 130.

  In the sound system according to the present embodiment, the microphone unit 45 collects sound by the microphone 46 and wirelessly transmits the sound signal from the transmission unit 47. The audio signal transmitted from the microphone unit 45 is received by the receiving unit 150 and input to the control unit 130 in the audio device 14, and is applied to the stacked piezoelectric element 61 from the control unit 130 via the piezoelectric element driving unit 120. . As a result, the contact surface on which the audio device 14 is placed and the piezoelectric vibrating portion 60 is in contact vibrates to generate reproduced sound.

  Therefore, also in the present embodiment, as in the above-described embodiment, the sound device 14 can generate sound with a small volume difference over a wide range via the mounting surface of the sound device 14. In addition, since the audio signal is wirelessly transmitted from the microphone unit 45 to the audio device 14, the microphone unit 45 and the audio device 14 can be separated from each other within a receivable range of the audio signal by the audio device 14. Therefore, for example, since the microphone unit 45 and the audio device 14 can be placed on different placement surfaces or placed in different rooms and voices can be remotely output, a more flexible usage mode is possible. , Versatility can be improved. Note that the microphone unit 45 and the audio device 14 are not limited to one, and a plurality of each may be provided.

  The present invention is not limited to the above-described embodiment, and many variations or modifications are possible. For example, in the above embodiment, the structure for fixing the piezoelectric vibrating portion 60 to the holding portion 100 is not limited to that shown in FIG. For example, as shown in FIGS. 21A to 21C, the piezoelectric vibrating unit 60 may be held by the holding unit 100. The holding unit 100 shown in FIG. 21A includes a wide slit 101a that opens to the bottom surface 20b, and a narrow slit 101b that continues to the slit 101a. The laminated piezoelectric element 61 has one end portion arranged in the narrow slit 101 b and the side surface fixed to the slit 101 b via the adhesive 102. Further, the wide slit 101 a is filled with a filler 103 such as silicone rubber or gel that does not hinder the expansion and contraction operation of the multilayer piezoelectric element 61 in the gap with the multilayer piezoelectric element 61. If the piezoelectric vibrating portion 60 is held by the holding portion 100 in this manner, the audio device 10 can be waterproofed more reliably without using a waterproof packing such as an O-ring. In addition, by covering the portion protruding from the bottom surface 20 b of the multilayer piezoelectric element 61 with an insulating cap, the multilayer piezoelectric element 61 can be reliably insulated.

  The holding unit 100 shown in FIG. 21B includes a tapered slit 101c that expands toward the bottom surface 20b, and a narrow slit 101d that continues to the tapered slit 101c. The laminated piezoelectric element 61 has one end portion disposed in the narrow slit 101 d and the side surface fixed to the slit 101 d via the adhesive 102. The tapered slit 101 c is filled with a filler 103 such as silicone rubber or gel that does not hinder the expansion and contraction operation of the multilayer piezoelectric element 61 in the gap with the multilayer piezoelectric element 61. With this configuration, the same effect as that of the holding unit 100 of FIG. 21A can be obtained, and since the tapered slit 101c is provided, the multilayer piezoelectric element 61 can be easily assembled to the holding unit 100. There are advantages that can be made.

  The holding unit 100 shown in FIG. 21C has a slit 101 having a uniform width as in the above embodiment, but the laminated piezoelectric element 61 has an end face on one end side via an adhesive 102. It is fixed to the slit 101. Further, an O-ring 62 is disposed at an appropriate position of the multilayer piezoelectric element 61 in the slit 101. Such a holding mode of the laminated piezoelectric element 61 is particularly suitable when the laminated piezoelectric element 61 has a lead wire connecting portion formed on a side electrode as shown in FIG. Etc. are advantageous.

  Further, in the above embodiment and the modified examples of FIGS. 21A to 21C, the piezoelectric vibrating portion 60 omits the cap 63, and the tip surface of the multilayer piezoelectric element 61 is formed directly or made of an insulating member or the like. You may make it contact a contact surface via a vibration transmission member. In addition, the piezoelectric element is not limited to the stack type stacked piezoelectric element described above, and a unimorph, bimorph, or stacked bimorph element may be used. FIG. 22 is a diagram showing a schematic configuration of a main part when a bimorph is used. The bimorph 65 has a long rectangular shape, one surface 65 a is exposed on the bottom surface 20 b of the housing 20, and both long ends are held by the holding unit 100. The holding unit 100 has an opening 101e that holds the bimorph 65, and the inner surface of the opening 101e on the back surface 65b side of the bimorph 65 is curved. According to this configuration, when the housing 20 is placed on the placement surface so that the bimorph 65 contacts the placement surface, and the bimorph 65 is driven by the audio signal, the bimorph 65 bends (curves) and vibrates. Thereby, the vibration of the bimorph 65 is transmitted to the placement surface (contact surface), and the placement surface (contact surface) functions as a vibration speaker, and a reproduction sound is generated from the placement surface (contact surface). Note that a coating layer such as polyurethane may be formed on the surface 65 a of the bimorph 65.

  Further, in FIG. 7, an LPF having the same characteristics as the LPF 123 may be provided between the signal processing circuit 121 and the booster circuit 122. In FIG. 7, the LPF 123 may be omitted by providing the equalizer of the signal processing circuit 121 with the function of the LPF 123.

  Moreover, in the said embodiment, although the to-be-contacted member was a table and the contact surface was demonstrated as a horizontal mounting surface of a table, the contact surface is not limited to this.

10, 11, 12, 13, 14 Audio device 20 Housing 20a Upper surface 20b Bottom surface 20c Side surface 30 Operation unit 40 Microphone 45 Microphone unit 46 Microphone 47 Transmitting unit 50 Foot 60 Piezoelectric vibration unit 61 Multilayer piezoelectric element (piezoelectric element)
62 O-ring 63 Cap 70 Damper 80 Speaker 90 Detection unit 100 Holding unit 101 Slit 102 Adhesive 110 Communication unit 120 Piezoelectric element driving unit 121 Signal processing circuit 122 Booster circuit 123 Low-pass filter (LPF)
130 Control unit 150 Reception unit 200 Placement surface (contact surface)

Claims (12)

The body,
A piezoelectric vibration unit having a piezoelectric element disposed in the housing;
A communication unit for receiving an audio signal;
In a state where the load of the sound device itself is applied to the piezoelectric vibration part, the piezoelectric element is deformed by applying the sound signal to the piezoelectric element, and the piezoelectric vibration part is deformed. Vibrating the contact surface in contact with the audio device by deformation to generate sound from the contact surface;
Audio device. The piezoelectric vibration part is disposed at a portion facing the contact surface of the housing.
The audio device according to claim 1. It has a microphone that collects audio and outputs audio signals.
The communication unit transmits an audio signal from the microphone.
The audio device according to claim 1 or 2. The microphone is held by the housing via a damper that reduces vibration caused by deformation of the piezoelectric vibration unit.
The audio device according to claim 3. The vibration direction of the piezoelectric element and the vibration direction of the diaphragm of the microphone intersect,
The audio device according to claim 3 or 4. The microphone is arranged separately from the housing,
The audio device according to claim 3. The communication unit receives the audio signal from another audio device;
The audio device according to any one of claims 3 to 6. A speaker that is arranged in the housing and that amplifies the audio signal;
A detection unit for detecting a contact state between the contact surface and the piezoelectric vibration unit;
A control unit that controls the speaker and the piezoelectric vibration unit based on the contact state detected by the detection unit;
The audio device according to any one of claims 1 to 7. The piezoelectric element is a laminated piezoelectric element, and expands and contracts along the lamination direction.
The audio device according to any one of claims 1 to 8. The piezoelectric vibration unit includes a covering member that transmits vibration due to deformation of the piezoelectric element to the contact surface to vibrate the contact surface.
The audio device according to any one of claims 1 to 9. The contact surface is a mounting surface on which the audio device is mounted.
The audio device according to any one of claims 1 to 10. An audio system including a microphone unit and a speaker unit,
The microphone unit includes a microphone that collects sound and outputs an audio signal, and a transmission unit that transmits the audio signal to the speaker unit.
The speaker unit includes a housing, a piezoelectric vibration unit having a piezoelectric element disposed in the housing, and a receiving unit that receives the audio signal.
In a state where the load of the sound device itself is applied to the piezoelectric vibration part, the piezoelectric element is deformed by applying the sound signal to the piezoelectric element, and the piezoelectric vibration part is deformed. Vibrating the contact surface in contact with the audio device by deformation to generate sound from the contact surface;
Voice system.

Images