Mouthpiece

Abstract

To convert air vibrations in a mouthpiece into electrical signals with a frequency characteristic as flat as possible.SOLUTION: A mouthpiece 1 in one embodiment includes a body part 70, a piezoelectric sensor 10, and a support structure 700. The body part 70 forms an air flow channel 80. The piezoelectric sensor 10 includes a piezoelectric element 110 having a porous layer that is compressed and deformed by air vibration, and generates a detection signal in response to the compressed deformation of the porous layer. The support structure 700 supports the piezoelectric element 110 so that it is positioned in the flow channel 80.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a mouthpiece of a wind instrument.

Background Art

[0002] In order to convert the sound of a wind instrument into an electrical signal, generally, a microphone arranged close to the wind instrument is used. This microphone acquires the air vibration spreading outside the wind instrument as the sound of the wind instrument. Technologies for acquiring the air vibration generated inside the wind instrument as the sound of the wind instrument have also been developed. For example, according to Patent Document 1, a technique for converting the air vibration in the mouthpiece into an electrical signal by a piezoelectric element formed of ceramics and embedded inside the mouthpiece of a wind instrument is disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Piezoelectric elements formed of ceramics are subject to various restrictions regarding the installation position. For example, since ceramics are easily cracked, piezoelectric elements formed of ceramics need to be fixed to the tube wall surface. At this time, in order not to transmit the vibration of the tube wall surface to the piezoelectric element, a member such as an epoxy resin must be arranged between the tube wall surface and the piezoelectric element. Due to such restrictions, the degree of freedom of the installation position is low, and depending on the restrictions, it has been difficult to bring the sound of the wind instrument closer to the sound indicated by the electrical signal. Therefore, it is desired to make the frequency characteristics flat when converting air vibration into an electrical signal.

[0005] One of the objectives of this invention is to convert air vibrations within the mouthpiece into electrical signals with the flattest possible frequency characteristics. [Means for solving the problem]

[0006] According to one embodiment, a mouthpiece is provided that includes a main body that forms an air passage, a piezoelectric sensor that includes a piezoelectric element having a porous layer that is compressed and deformed by the vibration of the air and generates a detection signal corresponding to the compressed deformation of the porous layer, and a support structure for supporting the piezoelectric element in the air passage.

[0007] The shape of the piezoelectric element is such that its longitudinal direction is in a specific direction, and the longitudinal direction of the piezoelectric element may be aligned with the direction of airflow.

[0008] The first surface of the piezoelectric element and the second surface opposite to the first surface may both be positioned with respect to the main body via air.

[0009] The piezoelectric element may be curved along the inner surface of the main body that defines the flow path.

[0010] The shape of the piezoelectric element is such that it has an elongation in a specific direction, and the elongation of the piezoelectric element may be aligned with the circumferential direction of the inner surface of the main body.

[0011] The support structure may include a recessed portion located on the surface of the main body facing the flow path. The piezoelectric element may be located in the recessed portion.

[0012] The piezoelectric sensor may include a plurality of piezoelectric elements. The detection signal may be generated by connecting the outputs from the plurality of piezoelectric elements in series.

[0013] The piezoelectric sensor may include a plurality of piezoelectric elements. The plurality of piezoelectric elements may include at least a first piezoelectric element and a second piezoelectric element. The first piezoelectric element may be arranged in the circumferential direction on the inner surface of the main body relative to the second piezoelectric element.

[0014] The piezoelectric sensor may include a plurality of piezoelectric elements. The plurality of piezoelectric elements may include at least a first piezoelectric element and a second piezoelectric element. The first piezoelectric element may be disposed closer to the main body portion than the second piezoelectric element.

[0015] The piezoelectric sensor may include a plurality of piezoelectric elements. The plurality of piezoelectric elements may include at least a first piezoelectric element and a second piezoelectric element. The second piezoelectric element may be disposed in the direction of the air flow with respect to the first piezoelectric element.

[0016] The piezoelectric sensor may generate a second detection signal using the output from a part of the plurality of piezoelectric elements.

Advantages of the Invention

[0017] According to the present invention, air vibrations in the mouthpiece can be converted into an electrical signal with as flat frequency characteristics as possible.

Brief Description of the Drawings

[0018] [Figure 1] It is a diagram showing a mouthpiece in the first embodiment. [Figure 2] It is a diagram showing a cross-sectional structure of the mouthpiece in the first embodiment. [Figure 3] It is a diagram showing a cross-sectional structure of the piezoelectric module in the first embodiment (A1-A2 cross-section in FIG. 1). [Figure 4] It is a developed view showing the piezoelectric module in the first embodiment. [Figure 5] It is a diagram for explaining a part of a cross-sectional structure of the piezoelectric module in the first embodiment (B1-B2 cross-section in FIG. 4) in an enlarged manner. [Figure 6] It is a diagram for explaining a circuit configuration of the piezoelectric sensor in the first embodiment. [Figure 7]It is a diagram for enlarging and explaining a part of the cross-sectional structure of the mouthpiece in the first embodiment (region SA in FIG. 2). [Figure 8] It is a diagram showing the cross-sectional structure of the mouthpiece in the second embodiment. [Figure 9] It is a diagram showing the cross-sectional structure of the piezoelectric module in the second embodiment. [Figure 10] It is a diagram showing the cross-sectional structure of the mouthpiece in the third embodiment. [Figure 11] It is a diagram showing the cross-sectional structure of the piezoelectric module in the third embodiment. [Figure 12] It is a diagram showing the cross-sectional structure of the mouthpiece in the fourth embodiment. [Figure 13] It is a diagram for explaining the circuit configuration of the piezoelectric sensor in the fourth embodiment. [Figure 14] It is a diagram showing the cross-sectional structure of the piezoelectric module in the fifth embodiment. [Figure 15] It is a diagram for enlarging and explaining a part of the cross-sectional structure of the piezoelectric module in the fifth embodiment. [Figure 16] It is a diagram showing the cross-sectional structure of the piezoelectric module in the sixth embodiment. [Figure 17] It is a diagram showing the cross-sectional structure of the mouthpiece in the seventh embodiment. [Figure 18] It is a diagram showing the cross-sectional structure of the piezoelectric module in the seventh embodiment.

Modes for Carrying Out the Invention

[0019] Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. The embodiments shown below are examples, and the present invention is not limited to these embodiments. In the drawings referenced in this embodiment, the same parts or parts having similar functions are denoted by the same or similar reference numerals (simply a number followed by A, B, etc.), and repeated descriptions may be omitted. In order to clarify the explanation, the drawings may be schematic in which dimensional ratios differ from actual ratios, or some parts of the configuration may be omitted from the drawings.

[0020] In one embodiment, the mouthpiece of a wind instrument has the function of converting the sound produced by the wind instrument into an electrical signal. This function is realized by a piezoelectric element that generates a voltage in response to the compression deformation of a porous layer. The configuration of such a mouthpiece will be described below.

[0021] <First Embodiment> Figure 1 shows a mouthpiece in the first embodiment. Figure 2 shows a cross-sectional structure of the mouthpiece in the first embodiment. The mouthpiece 1 shown in Figure 1 is, in this example, a mouthpiece used for a saxophone. The cross-section shown in Figure 2 is perpendicular to the surface of the table 790 of the mouthpiece 1 in contact with the reed 90 and corresponds to a surface passing through the center of the mouthpiece 1. The mouthpiece 1 includes a body 70 and a piezoelectric sensor 10. The body 70 includes an inlet 781 called a window and an outlet 785 formed in the shank 730. The body 70 forms an air passage. The inner surface of the body 70 defines the air passage 80. The passage 80 includes a chamber 810, a throat 830, and a bore 850. Air flowing in from the inlet 781 by the user blowing air passes through the chamber 810, throat 830, and bore 850 and flows out from the outlet 785.

[0022] The piezoelectric sensor 10 includes a piezoelectric module 100 and an output module 190. The piezoelectric module 100 includes a piezoelectric element 110 that generates an electrical signal in response to a given pressure. The piezoelectric module 100 is supported by a support structure 700 formed on the inner surface of the main body 70. The support structure 700 can also be described as a structure for supporting the piezoelectric element 110 in the flow path 80. In this example, the piezoelectric element 110 is located in the flow path 80 on the air outlet side of the throat 830, i.e., in the bore 850.

[0023] The output module 190 is electrically connected to the piezoelectric module 100 and amplifies and outputs the electrical signal generated in the piezoelectric module 100. The output module 190 may have a secondary battery as a power source, a replaceable primary battery, or terminals for receiving power from an external source. The configurations of the mouthpiece 1 will be described in more detail below.

[0024] Figure 3 shows the cross-sectional structure of the piezoelectric module in the first embodiment (cross section A1-A2 in Figure 1). As shown in Figure 3, the piezoelectric module 100 is a sheet-like member arranged in a curve along the inner surface of the main body 70. The piezoelectric module 100 includes protective films 120 and 130. The protective films 120 and 130 are, for example, insulating resin films and are arranged to sandwich the piezoelectric element 110.

[0025] The protective films 120 and 130 physically protect the piezoelectric element 110 and also protect it from moisture intrusion. The connection between the end 120e2 of protective film 120 and the end 130e1 of protective film 130 gives the piezoelectric module 100 a shape corresponding to the side surface of a roughly cylindrical shape, i.e., a cylindrical shape. The configuration of the piezoelectric module 100 will be further explained with reference to Figures 4 and 5, in addition to Figure 3.

[0026] Figure 4 is an unfolded view showing the piezoelectric module in the first embodiment. Figure 5 is a diagram for illustrating a part of the cross-sectional structure of the piezoelectric module in the first embodiment (B1-B2 cross-section in Figure 4) in an enlarged view. The unfolded view shown in Figure 4 corresponds to the state in which the piezoelectric module 100 is spread out on a plane by releasing the connection between the end 120e2 of the protective film 120 and the end 130e1 of the protective film 130. In this example, the shape of the piezoelectric element 110 as viewed in the direction shown in Figure 4 is a shape having a longitudinal side in a specific direction, and more specifically, it is approximately rectangular. The longitudinal direction of the piezoelectric element 110 corresponds to the direction along the long side of this rectangle. The shape of the piezoelectric element 110 may be other shapes having a longitudinal side in a specific direction, such as an ellipse, in addition to a rectangle. The longitudinal direction in an ellipse corresponds to the direction along the major axis. The shape of the piezoelectric element 110 may be a shape that does not have a longitudinal side in a specific direction, such as a square or a circle. The cross-section shown in Figure 5 corresponds to the plane obtained by cutting the piezoelectric element 110 in the longitudinal direction.

[0027] The piezoelectric element 110 is sealed by protective films 120 and 130. Therefore, there is a region around the piezoelectric element 110 where the protective films 120 and 130 are in direct contact, i.e., a region where the piezoelectric element 110 is not present. Hereinafter, the region of the piezoelectric module 100 where the piezoelectric element 110 is not present may be referred to as the non-detection region. On the other hand, the region where the piezoelectric element 110 is present may be referred to as the detection region.

[0028] The piezoelectric element 110 includes a porous layer 111, electrodes 112 and 113. Electrodes 112 and 113 are separated by the porous layer 111. The porous layer 111 is an electret layer formed in an insulating resin such as polypropylene, with many micropores 115, and holds an electric charge inside. This charge is pre-injected, for example, by corona discharge. Polarization occurs in each of the micropores 115 due to the voltage applied to electrodes 112 and 113 and the injected charge.

[0029] The porous layer 111 can be, for example, an electret material disclosed in International Publication No. 2018 / 101359. Electrodes 112 and 113 may be electrode layers disclosed in this document. The proportion of micropores 115 in the porous layer 111 is preferably 20% to 80%. This proportion corresponds to the porosity disclosed in International Publication No. 2018 / 101359. The lower limit of the density of the porous layer 111 is 0.2 g / cm³. 3 Preferably, 0.4 g / cm³ 3 This is more preferable. On the other hand, the upper limit of the density of the porous layer 111 is 0.8 g / cm³. 3 Preferably, 0.6 g / cm³ 3 This is more preferable. The lower limit of the elastic modulus in the thickness direction of the porous layer 111 is preferably 0.1 MPa, and more preferably 0.3 MPa. The upper limit of the elastic modulus in the thickness direction is preferably 10 MPa, and more preferably 2 MPa. The lower limit of the elastic modulus in the thickness direction of the porous layer 111 is preferably 0.1 MPa, and more preferably 0.3 MPa. The upper limit of the elastic modulus in the thickness direction is preferably 10 MPa, and more preferably 2 MPa. These elastic moduli are values ​​measured in accordance with JIS-K7161(2014).

[0030] When the porous layer 111 is compressed in the thickness direction, the amount of polarization changes due to the deformation of the micropores 115, causing the potential difference between electrodes 112 and 113 to fluctuate. In this way, the piezoelectric element 110 generates an electrical signal corresponding to the compressive deformation of the porous layer 111. In this example, the piezoelectric element 110 and the porous layer 111 can be said to have substantially the same shape when viewed from the surface of the piezoelectric module 100. The piezoelectric element 110 can also be described as the region where the porous layer 111, electrodes 112 and 113 overlap.

[0031] In this example, the piezoelectric module 100 includes connecting electrodes 182 and 183 arranged on the protective film 130. Electrode 112 is connected to connecting electrode 182. Electrode 113 is connected to connecting electrode 183. Therefore, the electrical signal corresponding to the compressive deformation of the porous layer 111 is output as a potential difference between connecting electrode 182 and connecting electrode 183. Electrode 112 and connecting electrode 182 may be formed integrally. Electrode 113 and connecting electrode 183 may be formed integrally. The protective film 120 includes ends 120e1 and 120e2 at both ends in the longitudinal direction. The protective film 130 includes ends 130e1 and 130e2 at both ends in the longitudinal direction. In this example, connecting electrodes 182 and 183 are arranged between ends 120e1 and 130e1.

[0032] The piezoelectric module 100 is a flexible sheet and can be bent. The sheet-like nature of the piezoelectric module 100 improves the degree of freedom when arranging it in the flow path 80. By bending the piezoelectric module 100 so that the protective film 120 is positioned on the outside and the protective film 130 is positioned on the inside, the longitudinal direction of the piezoelectric element 110 bends along the circumferential direction CD on the inner surface of the main body 70, as shown in Figure 3. The short direction of the piezoelectric element 110 is aligned with the direction of airflow in the flow path 80. At this time, as shown in Figure 3, the end 120e2 and the end 130e1 may be in contact. In this case, their relative positions may be fixed using an adhesive or the like.

[0033] The connecting electrodes 182 and 183 are both located on the protective film 130 between the ends 120e1 and 120e2. As shown in Figure 2, with the piezoelectric module 100 supported on the main body 70 by the support structure 700, the connecting electrode 182 is connected to the connecting electrode 192 of the output module 190, as shown in Figure 3. Although not visible in Figure 3, the connecting electrode 183 is similarly connected to a different connecting electrode than the connecting electrode 192. Through these connecting electrodes, the electrical signal generated by the piezoelectric module 100 is supplied to the output section 195 of the output module 190. The output section 195 includes a preamplifier for amplifying the electrical signal and a terminal for outputting the amplified electrical signal as a detection signal. The output section 195 does not necessarily include a preamplifier, and may include a filter that allows signals in a certain frequency band to pass through, such as a high-pass filter.

[0034] Figure 6 is a diagram illustrating the circuit configuration of the piezoelectric sensor in the first embodiment. The electrical signal generated in the piezoelectric module 100 is supplied to the output unit 195 via input terminals E1 and E2. The output unit 195 supplies a detection signal obtained by amplifying the supplied electrical signal to output terminals T1 and T2. This detection signal is a signal corresponding to the compression deformation of the porous layer 111. The output terminals T1 and T2 may be provided, for example, in the form of phone jacks. An external device acquires the detection signal from the output terminals T1 and T2. The detection signal may be provided to the external device in a different form from the output terminals T1 and T2, such as a flexible flat cable or coaxial cable. The output unit 195 may allow the external device to acquire the detection signal by transmitting it wirelessly. The external device may be, for example, a sound output device for outputting the detection signal as sound, a sound processing device for processing the detection signal, or a sound recording device for recording the detection signal.

[0035] Figure 7 is a diagram illustrating a magnified view of a portion of the cross-sectional structure of the mouthpiece in the first embodiment (region SA in Figure 2). The support structure 700 includes a recess formed on the surface of the main body 70 facing the flow path 80, which in this example includes a first recessed region 701, a second recessed region 703, and a third recessed region 705. The first recessed region 701 is located between the second recessed region 703 and the third recessed region 705. The first recessed region 701 is deeper than the second recessed region 703 and the third recessed region 705.

[0036] The support structure 700 supports the piezoelectric module 100 in the flow path 80 by contacting the protective film 120 (see Figure 3) positioned on the outer surface side of the piezoelectric module 100 with the second recessed region 703 and the third recessed region 705. In this example, the portion of the protective film 120 corresponding to the non-detection region of the piezoelectric module 100 (the region where the piezoelectric element 110 does not exist) contacts the support structure 700. In other words, the portion of the protective film 120 corresponding to the detection region of the piezoelectric module 100 (the region where the piezoelectric element 110 exists) is separated from the main body 70 by the first recessed region 701. Therefore, it can also be said that the piezoelectric element 110 is supported in the flow path 80 by the support structure 700 via the protective films 120 and 130.

[0037] In this case, it is preferable that the piezoelectric module 100 is housed in a recess of the support structure 700, so that there is no portion of the piezoelectric module 100 protruding from the main body 70 towards the flow path 80. That is, the depths of the second recessed region 703 and the third recessed region 705 may be greater than the sum of the thickness of the protective film 120, the thickness of the piezoelectric element 110, and the thickness of the protective film 130. It is preferable that the difference between this sum and the depth is small.

[0038] In this way, the influence of the piezoelectric module 100 on the shape of the flow path 80 can be reduced. As a result, the difference in sound quality between when the piezoelectric module 100 is present and when it is not can be reduced. The support structure 700 may have a support member that contacts the piezoelectric module 100 from the flow path 80 side. In this case, at least one of the second recessed region 703 and the third recessed region 705 and the support member sandwich the end of the piezoelectric module 100.

[0039] The piezoelectric element 110 is positioned relative to the main body 70 via air, as the portion of the piezoelectric module 100 corresponding to the detection area is separated from the main body 70 by the first recessed area 701. More specifically, the first surface and the second surface opposite to the first surface of the porous layer 111 are positioned relative to the main body 70 via air. The first surface and the second surface correspond to the electrode 112 side and electrode 113 side of the porous layer 111, respectively. Therefore, the first surface of the porous layer 111 corresponds to the surface on the main body 70 side.

[0040] In this way, the detection area is positioned via air without contacting the main body 70, making it less likely for vibrations transmitted to the mouthpiece 1 to be transmitted to the porous layer 111. As a result, it is possible to reduce the influence of vibrations other than the air vibration component in the flow path 80 on the compressive deformation of the porous layer 111. The vibrations transmitted to the mouthpiece 1 are, for example, vibrations caused by key operation of the wind instrument to which the mouthpiece 1 is connected. Since such vibrations are components different from the sound produced by the wind instrument, it is preferable that they are not included in the detection signal as much as possible.

[0041] When a wind instrument is played using the mouthpiece 1 connected to it, air vibrations are generated inside the wind instrument. These air vibrations also occur in the flow path 80 within the mouthpiece 1. The air vibrations generated in the flow path 80 compress and deform the porous layer 111 placed in the flow path 80. The porous layer 111 has an acoustic impedance close to that of air due to the presence of numerous micropores 115.

[0042] Therefore, the electrical signal obtained by the compression deformation of the porous layer 111 is a signal that converts the air vibrations in the channel 80 with the flattest possible frequency characteristics. Furthermore, by positioning the piezoelectric module 100 in the region that corresponds to the antinode of the air vibrations in the channel 80, the accuracy of air vibration detection can be improved.

[0043] <Second Embodiment> Figure 8 shows the cross-sectional structure of the mouthpiece in the second embodiment. Figure 9 shows the cross-sectional structure of the piezoelectric element in the second embodiment. Figure 8 corresponds to Figure 2 in the first embodiment. Figure 9 corresponds to Figure 3 in the first embodiment. In the mouthpiece 1 of the first embodiment, the piezoelectric element 110 is arranged so that its longitudinal direction is along the circumferential direction CD of the inner surface of the main body 70. In the mouthpiece 1A of the second embodiment, the piezoelectric module 100A is arranged so that the longitudinal direction of the piezoelectric element 110A is along the direction FD of airflow in the flow path 80A.

[0044] The mouthpiece 1A includes a piezoelectric sensor 10A and a main body 70A. The inner surface of the main body 70A defines the flow path 80A. The piezoelectric sensor 10A includes a piezoelectric module 100A and an output module 190A. The output module 190A has the same function as the output module 190 in the first embodiment.

[0045] The piezoelectric module 100A is a sheet-like member that is curved and arranged along the inner surface of the main body 70A. The piezoelectric module 100A includes a piezoelectric element 110A and protective films 120A and 130A. Protective films 120A and 130A are arranged so as to sandwich the piezoelectric element 110A. As described above, the longitudinal direction of the piezoelectric element 110A is along the direction FD of airflow in the flow path 80A. The short direction of the piezoelectric element 110A is along the circumferential direction CD of the inner surface of the main body 70A. Thus, the relationship between the longitudinal and short directions is reversed between the piezoelectric module 100A in the second embodiment and the piezoelectric module 100 in the first embodiment.

[0046] The support structure 700A includes recesses formed on the surface of the main body 70A facing the flow path 80A, and in this example includes a first recessed area 701A, a second recessed area 703A, a third recessed area 705A, a first support member 707A, and a second support member 709A. The first recessed area 701A is positioned between the second recessed area 703A and the third recessed area 705A. The first support member 707A and the second support member 709A support the piezoelectric module 100A from the flow path 80A side. The first support member 707A and the second recessed area 703A sandwich the end of the piezoelectric module 100A. The second support member 709A and the third recessed area 705A sandwich the end of the piezoelectric module 100A.

[0047] The first recessed region 701A is more deeply recessed than the second recessed region 703A and the third recessed region 705A. The support structure 700A supports the piezoelectric module 100A in the flow path 80A by contacting the protective film 120A, which is positioned on the outer surface side of the piezoelectric module 100A, with the second recessed region 703A and the third recessed region 705A. In this example, the portion of the protective film 120A corresponding to the non-detection region of the piezoelectric module 100A is in contact with the support structure 700A. With the piezoelectric module 100A supported by the support structure 700A, the piezoelectric module 100A and the output module 190A are electrically connected.

[0048] Because the longitudinal direction of the piezoelectric element 110A is aligned with the longitudinal direction of the mouthpiece 1A, i.e., the direction of airflow FD, the antinodes of air vibrations generated in the flow path 80A within the mouthpiece 1A are more likely to be included in the detection area. Therefore, redundancy is increased with respect to the accuracy of the position in which the piezoelectric element 110A is placed.

[0049] <Third Embodiment> Figure 10 shows the cross-sectional structure of the mouthpiece in the third embodiment. Figure 11 shows the cross-sectional structure of the piezoelectric module in the third embodiment. Figure 10 corresponds to Figure 2 in the first embodiment. Figure 11 corresponds to Figure 3 in the first embodiment. The mouthpiece 1B of the third embodiment includes a piezoelectric module 100B arranged in a planar shape, rather than piezoelectric modules 100, 100A arranged in a curved shape, i.e., a curved shape, as in the mouthpiece 1 of the first embodiment and the mouthpiece 1A of the second embodiment.

[0050] The mouthpiece 1B includes a piezoelectric sensor 10B and a main body 70B. The inner surface of the main body 70B defines the flow path 80B. The piezoelectric sensor 10B includes a piezoelectric module 100B and an output module 190B. The output module 190B has the same function as the output module 190 in the first embodiment.

[0051] Piezoelectric module 100B, like piezoelectric module 100, includes a piezoelectric element 110B and protective films 120B and 130B. Protective films 120B and 130B are arranged so as to sandwich the piezoelectric element 110B. The longitudinal direction of the piezoelectric element 110B is aligned with the direction FD of airflow in the flow path 80B, and the short direction of the piezoelectric element 110B is not curved, so that the piezoelectric element 110B as a whole has a planar shape. Thus, piezoelectric module 100B is a sheet-like member arranged in a planar shape as described above.

[0052] The support structure 700B includes a first projection 710B and a second projection 720B that protrude toward the flow path 80B side of the main body 70B. The second projection 720B is located in direction FD relative to the first projection 710B. The first projection 710B and the second projection 720B support the piezoelectric module 100B by sandwiching both longitudinal ends of the piezoelectric module 100B, respectively. The portions of the piezoelectric module 100B supported by the support structure 700B all correspond to non-detection regions.

[0053] When the piezoelectric module 100B is supported by the support structure 700B, the piezoelectric module 100B and the output module 190B are electrically connected by contact between their connecting electrodes. The support structure 700B may support both ends of the piezoelectric module 100B in the shorter direction. The longitudinal and short directions may be reversed by adopting a shape in the piezoelectric module 100B where the length of direction FD is short.

[0054] By using a piezoelectric module 100B arranged in a planar shape, it becomes easier to support the piezoelectric module 100B within the mouthpiece 1B. Furthermore, since the piezoelectric module 100B is positioned away from the inner surface of the main body 70B by the support structure 700B, it is possible to reduce the inclusion of vibration components other than air vibrations in the detection signal.

[0055] By applying a configuration equivalent to the support structure 700B to the mouthpiece 1 in the first embodiment, the piezoelectric module 100 may be positioned away from the inner surface of the main body 70. By applying a configuration equivalent to the support structure 700B to the mouthpiece 1A in the second embodiment, the piezoelectric module 100A may be positioned away from the inner surface of the main body 70A.

[0056] <Fourth Embodiment> Figure 12 shows the cross-sectional structure of the mouthpiece in the fourth embodiment. Figure 12 corresponds to Figure 2 in the first embodiment. The mouthpiece 1C of the fourth embodiment includes a piezoelectric sensor 10C and a main body 70C. The inner surface of the main body 70C defines the flow path 80C. The piezoelectric sensor 10C includes a piezoelectric module 100C1, a piezoelectric module 100C2, and an output module 190C. In this example, the piezoelectric sensor 10C uses two piezoelectric modules 100C1 and 100C2, but more piezoelectric modules may be used.

[0057] The piezoelectric module 100C2 is positioned in the direction FD of airflow in the flow path 80C relative to the piezoelectric module 100C1. Both piezoelectric modules 100C1 and 100C2 have the same configuration as the piezoelectric module 100 in the first embodiment. The piezoelectric module 100C1 includes a piezoelectric element 110C1 and is supported by a support structure 700C1. The piezoelectric module 100C2 includes a piezoelectric element 110C2 and is supported by a support structure 700C2. Both support structures 700C1 and 700C2 have the same configuration as the support structure 700 in the first embodiment.

[0058] Piezoelectric modules 100C1 and 100C2 are electrically connected to output module 190C. Several circuit configurations are possible for the piezoelectric sensor 10C, specifically the circuit configuration from the electrical signals generated in piezoelectric modules 100C1 and 100C2 to the output of the detection signal. Three examples of circuit configurations will be explained below.

[0059] Figure 13 is a diagram illustrating the circuit configuration of the piezoelectric sensor in the fourth embodiment. The output section 195C of the output module 190C is supplied with an electrical signal generated in the piezoelectric module 100C1 (hereinafter sometimes referred to as electrical signal Sa1) via input terminals E1 and E2. The output section 195C is supplied with an electrical signal generated in the piezoelectric module 100C2 (hereinafter sometimes referred to as electrical signal Sa2) via input terminals E3 and E4.

[0060] The output unit 195C supplies detection signals to output terminals T1 and T2 using electrical signals Sa1 and Sa2. When a control signal is supplied to the output unit 195C via the control terminal CL, the output unit 195C controls the connection relationship of input terminals E1 to E4 based on the control signal. The control signal is supplied, for example, from a switch provided on the mouthpiece 1C or from an external device. By controlling this connection relationship, the detection signals supplied to output terminals T1 and T2 can be changed.

[0061] In this example, the output unit 195C can be switched between four detection modes (Mode A to Mode D) by a control signal. Mode A is a mode for expanding the detection range. In Mode A, the output unit 195C obtains a detection signal by amplifying the potential difference between the node connecting E1 and E3 and the node connecting E2 and E4. With this connection method, the piezoelectric module 100C1 and the piezoelectric module 100C2 are connected in parallel. That is, the output of piezoelectric element 110C1 and the output of piezoelectric element 110C2 are connected in parallel.

[0062] Mode B is a mode for increasing the output level of the detection signal. In Mode B, the output unit 195C connects E2 and E3 and amplifies the potential difference between E1 and E4 to obtain the detection signal. With this connection method, piezoelectric modules 100C1 and 100C2 are connected in series. That is, the output of piezoelectric element 110C1 and the output of piezoelectric element 110C2 are connected in series. With Mode B, the output level of the detection signal is higher than in Modes C and D, which will be described later, so the detection sensitivity can be increased.

[0063] Mode C is a mode for using only the detection region of the piezoelectric module 100C1. In Mode C, the output unit 195C obtains the detection signal using the electrical signal Sa1 supplied from E1 and E2, without using E3 and E4. That is, the detection signal in Mode C is the same as in the first embodiment.

[0064] Mode D is a mode for using only the detection region of the piezoelectric module 100C2. In Mode D, the output unit 195C obtains the detection signal using the electrical signal Sa2 supplied from E3 and E4, without using E1 and E2.

[0065] Thus, the detection signals in modes C and D are generated using the output from either piezoelectric element 110C1 or 110C2. Depending on the relative positions of piezoelectric elements 110C1 and 110C2, switching between mode C and mode D will change the relationship between the antinode position of the air vibration and the detection area, thus changing the timbre of the detection signal.

[0066] The output unit 195C was set to one of four modes as the detection mode by a control signal, but it may be fixed to one of the modes. The output unit 195C may also output detection signals corresponding to multiple modes in parallel by supplying detection signals to more output terminals.

[0067] <Fifth Embodiment> Figure 14 shows the cross-sectional structure of the piezoelectric module in the fifth embodiment. Figure 15 is a diagram for illustrating a part of the cross-sectional structure of the piezoelectric module in the fifth embodiment in an enlarged view. Figure 14 corresponds to Figure 3 in the first embodiment. Figure 15 corresponds to Figure 5 in the first embodiment. The piezoelectric module 100D in the fifth embodiment includes two piezoelectric elements 110D1 and 110D2.

[0068] The piezoelectric module 100D is arranged along the circumferential direction CD on the inner surface of the main body 70. The piezoelectric module 100D is bent at the bent portion BD, causing the two piezoelectric elements 110D1 and 110D2 to overlap. Therefore, piezoelectric element 110D1 is positioned closer to the main body 70 than piezoelectric element 110D2. In this example, the piezoelectric module 100D in the piezoelectric sensor 10D includes two piezoelectric elements 110D1 and 110D2, but it may include more piezoelectric elements.

[0069] Two piezoelectric elements 110D1 and 110D2 are sealed by protective films 120D and 130D. Two detection regions corresponding to the two piezoelectric elements 110D1 and 110D2 are surrounded by non-detection regions. The region between piezoelectric elements 110D1 and 110D2 where protective films 120D and 130D are in contact is the bent portion BD. Piezoelectric element 110D1 includes a porous layer 111D1, an electrode 112D1, and an electrode 113D1. Piezoelectric element 110D2 includes a porous layer 111D2, an electrode 112D2, and an electrode 113D2.

[0070] In this example, electrodes 113D1 and 113D2 are electrically connected via wiring. Connecting electrode 182D is connected to electrode 112D1, and another connecting electrode (not shown) is connected to electrode 112D2. Therefore, piezoelectric elements 110D1 and 110D2 are connected in series between the two connecting electrodes.

[0071] As with the piezoelectric sensor 10D, multiple piezoelectric elements that constitute the detection area are arranged in overlapping and series connections, making it possible to increase the output level of the detection signal compared to the piezoelectric sensor 10 in the first embodiment. Because the output level of the detection signal is increased, the detection sensitivity can be increased.

[0072] <Sixth Embodiment> Figure 16 shows the cross-sectional structure of the piezoelectric module in the sixth embodiment. Figure 16 corresponds to Figure 3 in the first embodiment. The piezoelectric module 100E in the sixth embodiment includes two piezoelectric elements 110E1 and 110E2.

[0073] The piezoelectric module 100E has a similar shape to the piezoelectric module 100D shown in Figure 15, but without the bent portion BD. The piezoelectric module 100E is arranged along the circumferential direction CD on the inner surface of the main body 70. The piezoelectric element 110E1 is arranged along the circumferential direction CD relative to the piezoelectric element 110E2. In this example, the piezoelectric module 100E in the piezoelectric sensor 10E includes two piezoelectric elements 110E1 and 110E2 connected in series, but may include more piezoelectric elements.

[0074] By connecting multiple piezoelectric elements in series, as in the piezoelectric sensor 10E, the detection range becomes narrower than that of the piezoelectric sensor 10 in the first embodiment, while the output level of the detection signal can be increased. Because the output level of the detection signal is increased, the detection sensitivity can be increased.

[0075] <Seventh Embodiment> Figure 17 shows the cross-sectional structure of the mouthpiece in the seventh embodiment. Figure 17 corresponds to Figure 2 in the first embodiment. The mouthpiece 1F of the seventh embodiment includes a piezoelectric sensor 10F and a main body 70F. The inner surface of the main body 70F defines the flow path 80F. The piezoelectric sensor 10F includes a piezoelectric module 100F1, a piezoelectric module 100F2, and an output module 190F. In this example, the piezoelectric sensor 10F uses two piezoelectric modules 100F1 and 100F2, but more piezoelectric modules may be used.

[0076] The piezoelectric module 100F2 is positioned relative to the piezoelectric module 100F1 in the airflow direction FD in the flow path 80C. The relative positions of the piezoelectric module 100F1 and the piezoelectric module 100F2 may be reversed. The piezoelectric module 100F1 has the same configuration as the piezoelectric module 100 in the first embodiment. The piezoelectric module 100F1 includes a piezoelectric element 110F1 and is supported by a support structure 700F1. The support structure 700F1 has the same configuration as the support structure 700 in the first embodiment.

[0077] Figure 18 shows the cross-sectional structure of the piezoelectric module in the seventh embodiment. Figure 18 corresponds to Figure 3 in the first embodiment with respect to the piezoelectric module 100F2. The piezoelectric module 100F1 is the same as in Figure 3. The piezoelectric element 110F2 in the piezoelectric module 100F2 is sealed by protective films 120F2 and 130F2. The piezoelectric module 100F2 is supported by a support structure 700F2 formed on the inner surface of the main body 70F. The support structure 700F2 does not have a configuration corresponding to the first recessed region 701. Therefore, the protective film 120F2 is in contact with the main body 70F even in the detection region.

[0078] In this example, a weight layer 135F2 is placed on the inner side of the protective film 130F2, which is located on the flow path 80F side. The weight layer 135F2 is preferably made of a material with a higher specific gravity than the protective film 130F2, such as copper foil. The weight layer 135F2 does not have to be a metal layer; it may be an insulating layer.

[0079] Since the piezoelectric module 100F1 is the same as the piezoelectric module 100 in the first embodiment, it is suitable for converting air vibrations in a wind instrument into a detection signal. On the other hand, the piezoelectric module 100F2 is susceptible to vibrations transmitted from the wind instrument to the mouthpiece 1F (hereinafter sometimes referred to as the pipe vibration component) by contacting the inner surface of the main body 70F. Furthermore, the vibrations transmitted from the main body 70 are amplified by the weight layer 135F2 and contribute to the compressive deformation of the piezoelectric element 110F2. As a result, the electrical signal generated by the piezoelectric module 100F2 contains a large amount of the pipe vibration component.

[0080] The output module 190F is supplied with an electrical signal generated by the piezoelectric module 100F1 (hereinafter sometimes referred to as electrical signal Sb1) and an electrical signal generated by the piezoelectric module 100F2 (hereinafter sometimes referred to as electrical signal Sb2). The output module 190F supplies two detection signals, obtained by amplifying electrical signal Sb1 and electrical signal Sb2 respectively, to its output terminals. In this case, the output module 190F may be provided with output terminals for outputting the two detection signals. When output terminals T1 and T2 are used as in the first embodiment, the output module 190F may output a single detection signal by performing signal processing using the two detection signals, or it may output a detection signal by applying the circuit configuration of the fourth embodiment.

[0081] The ratio of the tube vibration component to the air vibration component differs between electrical signal Sb1 and electrical signal Sb2. Therefore, the signal processing described above may utilize this difference in ratio. For example, output module 190F may generate a detection signal that emphasizes the tube vibration component or a detection signal that emphasizes the air vibration component by signal processing using electrical signals Sb1 and Sb2.

[0082] <Variation> The present invention is not limited to the embodiments described above, and includes various other modifications. For example, the embodiments described above are described in detail for the purpose of clearly illustrating the present invention, and are not necessarily limited to those having all the configurations described. It is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. It is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations. Some modifications are described below. They are described as examples of modifications of the first embodiment, but they can also be applied as examples of modifications of other embodiments.

[0083] (1) The piezoelectric sensor 10 was placed in the mouthpiece used for the saxophone, but it may also be placed in the mouthpiece used for woodwind instruments other than the saxophone. For example, the piezoelectric sensor 10 may be placed in the mouthpiece of a woodwind instrument that uses a single reed. In the case of a woodwind instrument that uses a double reed, it may be placed in a position corresponding to the mouthpiece. The position corresponding to the mouthpiece is, for example, the tube in the case of an oboe, and the vocal in the case of a bassoon. It may also be placed in the mouthpiece of a woodwind instrument that does not use a reed. In any case of a mouthpiece, the piezoelectric sensor 10 should be placed so that the detection area is located near the antinode of air vibration in the flow path. In the case of a woodwind instrument that does not use a reed, for example, the mouthpiece of a flute, the piezoelectric sensor 10 should be placed in the head joint.

[0084] The piezoelectric sensor 10 may be applied to the mouthpiece of a brass instrument. In this case, it may be located in the cup of the airflow path in the mouthpiece, or it may be located elsewhere. Locations other than the cup correspond to, for example, the throat or downstream of the throat, such as the backbore. In the case of locations other than the cup, lip vibrations become less likely to be detected.

[0085] (2) The support structure 700 may support the piezoelectric module 100 so that it can be attached to the mouthpiece 1, or it may support it so that it is fixed to the mouthpiece 1. If the piezoelectric module 100 is attached to the mouthpiece 1 so that it can be attached to the mouthpiece 1, it can be replaced if it malfunctions. If the piezoelectric module 100 is fixed to the mouthpiece 1, the piezoelectric module 100 and the output module 190 may be configured as a single unit.

[0086] If the piezoelectric module 100 is cylindrical, it can be deformed to be introduced into the mouthpiece 1, and then returned to its original shape to be supported by the support structure 700. At this time, a positioning structure for aligning the position of the connecting electrodes may be provided in both the support structure 700 and the piezoelectric module 100. Furthermore, at least a part of the output module 190 may be detachably arranged with respect to the mouthpiece 1. In this case, the piezoelectric sensor 10 as a whole may be removable from the mouthpiece 1.

[0087] (3) The inner surface of the mouthpiece 1 has a curved shape and a roughly circular cross-section, but it may also have a shape that is a combination of planes and a roughly rectangular cross-section. When the inner surface of the mouthpiece has a shape that is a combination of planes, it is preferable that the piezoelectric elements are arranged so as not to straddle two planes. That is, it is preferable that one piezoelectric element is arranged corresponding to one plane. In this case, one piezoelectric element will have a planar shape and will not be curved.

[0088] (4) The piezoelectric module 100 may be arranged inside the mouthpiece 1 in a spiral shape. In this case as well, the piezoelectric module 100 can be said to be bent along the inner surface of the main body 70. [Explanation of symbols]

[0089] 1,1A,1B,1C,1F: Mouthpiece, 10,10A,10B,10C,10D,10E,10F: Piezoelectric sensor, 70,70A,70B,70C,70F: Main body, 80,80A,80B,80C: Flow path, 90: Lead, 100,100A,100B,100C1,100C2,100D,100E,100F1,100F2: Pressure Electrical module, 110, 110A, 110B, 110C1, 110C2, 110D1, 110D2, 110E1, 110E2, 110F1, 110F2: Piezoelectric element, 111, 111D1, 111D2: Porous layer, 112, 112D1, 112D2: Electrode, 113, 113D1, 113D2: Electrode, 115: Micropore, 120, 120A, 1 20B, 120D, 120F2: Protective film; 130, 130A, 130B, 130D, 130F2: Protective film; 135F2: Weight layer; 182: Connection electrode; 183: Connection electrode; 190, 190A, 190B, 190C, 190F: Output module; 192: Connection electrode; 195, 195C: Output section; 700, 700A, 700B 700C1, 700C2, 700F1, 700F2: Support structure, 701, 701A: First recessed area, 703, 703A: Second recessed area, 705, 705A: Third recessed area, 707A: First support member, 709A: Second support member, 781: Inlet, 785: Outlet, 790: Table, 810: Chamber, 830: Throat, 850: Bore

Claims

1. The main body forms an air passage, A piezoelectric sensor includes a piezoelectric element having a porous layer that undergoes compression deformation due to the vibration of the air, and generates a detection signal corresponding to the compression deformation of the porous layer, A support structure for supporting the piezoelectric element in the aforementioned flow path, Includes, The shape of the piezoelectric element is such that it has an elongated side in a specific direction. The longitudinal direction of the piezoelectric element is aligned with the direction of airflow, A mouthpiece in which air exists between the first surface of the piezoelectric element and the main body, and the second surface opposite to the first surface faces the flow path.

2. The main body forms an air passage, A piezoelectric sensor includes a piezoelectric element having a porous layer that undergoes compression deformation due to the vibration of the air, and generates a detection signal corresponding to the compression deformation of the porous layer, A support structure for supporting the piezoelectric element in the aforementioned flow path, Includes, A mouthpiece in which air exists between the first surface of the piezoelectric element and the main body, and the second surface opposite to the first surface faces the flow path.

3. The mouthpiece according to claim 1 or claim 2, wherein the piezoelectric element is curved along the inner surface of the main body that defines the flow path.

4. The main body forms an air passage, A piezoelectric sensor includes a piezoelectric element having a porous layer that undergoes compression deformation due to the vibration of the air, and generates a detection signal corresponding to the compression deformation of the porous layer, A support structure for supporting the piezoelectric element in the aforementioned flow path, Includes, The piezoelectric element is bent along the inner surface of the main body that defines the flow path. The shape of the piezoelectric element is such that it has an elongated side in a specific direction. The longitudinal direction of the piezoelectric element is aligned with the circumferential direction of the inner surface of the main body, A mouthpiece in which air exists between the first surface of the piezoelectric element and the main body, and the second surface opposite to the first surface faces the flow path.

5. The support structure includes a recessed portion located on the surface of the main body that faces the flow path, The mouthpiece according to any one of claims 1 to 4, wherein the piezoelectric element is arranged in the recessed portion.

6. The piezoelectric sensor includes a plurality of piezoelectric elements, The mouthpiece according to any one of claims 1 to 5, wherein the detection signal is generated by connecting the outputs from the plurality of piezoelectric elements in series.

7. The main body forms an air passage, A piezoelectric sensor includes a piezoelectric element having a porous layer that undergoes compression deformation due to the vibration of the air, and generates a detection signal corresponding to the compression deformation of the porous layer, A support structure for supporting the piezoelectric element in the aforementioned flow path, Includes, The piezoelectric sensor includes a plurality of piezoelectric elements, The plurality of piezoelectric elements include at least a first piezoelectric element and a second piezoelectric element. The first piezoelectric element is arranged in the circumferential direction on the inner surface of the main body relative to the second piezoelectric element in the mouthpiece.

8. The piezoelectric sensor includes a plurality of piezoelectric elements, The plurality of piezoelectric elements include at least a first piezoelectric element and a second piezoelectric element. The mouthpiece according to any one of claims 1 to 6, wherein the first piezoelectric element is positioned closer to the main body than the second piezoelectric element.

9. The main body forms an air passage, A piezoelectric sensor includes a piezoelectric element having a porous layer that undergoes compression deformation due to the vibration of the air, and generates a detection signal corresponding to the compression deformation of the porous layer, A support structure for supporting the piezoelectric element in the aforementioned flow path, Includes, The piezoelectric sensor includes a plurality of piezoelectric elements, The plurality of piezoelectric elements include at least a first piezoelectric element and a second piezoelectric element. The second piezoelectric element is a mouthpiece positioned relative to the first piezoelectric element in the direction of airflow.

10. The mouthpiece according to any one of claims 6 to 9, wherein the piezoelectric sensor generates a second detection signal using the output from some of the plurality of piezoelectric elements.

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