Detection system and musical instrument

Abstract

Provided is a detection system that generates a detection signal corresponding to the distance between a displaceable first coil and a second coil that generates a magnetic field by the supply of a drive signal, and that suppresses a reduction in detection accuracy due to position errors of the first coil and the second coil. The movable coil includes a first portion and a second portion arranged along the Y-axis, and the detection coil includes a third portion facing the first portion and a fourth portion facing the second portion. The outer dimension of the first portion in the Y-axis direction is equal to or less than the outer dimension of the third portion in the Y-axis direction, and the outer dimension of the second portion in the Y-axis direction is equal to or less than the outer dimension of the fourth portion in the Y-axis direction. The distance between the center of the first portion and the center of the second portion exceeds the distance between the center of the third portion and the center of the fourth portion. The center of the third portion and the center of the fourth portion are located between the center of the first portion and the center of the second portion.

Description

Technical Field

[0001] The present disclosure relates to a technique for detecting displacement using magnetism. Background Art

[0002] For example, various techniques for detecting displacement of movable members such as keys or hammer shanks in keyboard instruments have been proposed. For example, Patent Document 1 discloses a keyboard instrument that generates a detection signal corresponding to the distance between a first coil provided in a performance operating member and a second coil generating a magnetic field.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2021 / 100448 Summary of the invention

[0006] Problems to be solved by the invention

[0007] An error may occur in the positions of the first coil and the second coil. Sometimes, when an error occurs in the positions of the first coil and the second coil, the detection accuracy is reduced due to the error. Considering the above situation, an object of one embodiment of the present invention is to suppress the reduction of the detection accuracy caused by the error in the positions of the first coil and the second coil in a structure for generating a detection signal corresponding to the distance between the first coil capable of displacement and the second coil that generates a magnetic field by supplying a drive signal.

[0008] Means for solving problems

[0009] In order to solve the above problems, a detection system involved in one embodiment of the present invention is a detection system comprising a first coil that can be displaced and a second coil that generates a magnetic field by supplying a driving signal, and generates a detection signal corresponding to the distance between the first coil and the second coil, wherein the first coil includes a first part and a second part arranged along a first axis, the second coil includes a third part opposite to the first part and a fourth part opposite to the second part, a first outer dimension of the first part in the direction of the first axis is less than a third outer dimension of the third part in the direction of the first axis, a second outer dimension of the second part in the direction of the first axis is less than a fourth outer dimension of the fourth part in the direction of the first axis, a first distance between the center of the first part and the center of the second part exceeds a second distance between the center of the third part and the center of the fourth part, and the center of the third part and the center of the fourth part are located between the center of the first part and the center of the second part in the direction of the first axis.

[0010] A musical instrument according to one embodiment of the present disclosure is a musical instrument including a movable member that is displaced according to a playing operation and a detection system, the detection system including: a first coil provided on the movable member; and a second coil that generates a magnetic field by supplying a driving signal, the detection system generating a detection signal corresponding to a distance between the first coil and the second coil, the first coil including a first portion and a second portion arranged along a first axis, the second coil including a third portion opposite to the first portion and a fourth portion opposite to the second portion, a first outer dimension of the first portion in the direction of the first axis being less than a third outer dimension of the third portion in the direction of the first axis, a second outer dimension of the second portion in the direction of the first axis being less than a fourth outer dimension of the fourth portion in the direction of the first axis, a first distance between a center of the first portion and a center of the second portion exceeding a second distance between a center of the third portion and a center of the fourth portion, and a center of the third portion and a center of the fourth portion being located between a center of the first portion and a center of the second portion in the direction of the first axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 1 is a block diagram showing the structure of a keyboard instrument in the first embodiment.

[0012] Figure 2 It is a side view illustrating the structure of the keyboard unit.

[0013] Figure 3 It is a block diagram illustrating the configuration of a detection system and a control system.

[0014] Figure 4 is the circuit diagram of the magnetic sensor.

[0015] Figure 5 is a block diagram illustrating the structure of a driving circuit.

[0016] Figure 6 It is a top view of the detected part.

[0017] Figure 7 yes Figure 6 Cross-sectional view along line VII-VII.

[0018] Figure 8 It is a top view of the signal generation unit.

[0019] Fig. 9 yes Figure 8 Cross-sectional view along line IX-IX.

[0020] Fig.10 This is a schematic diagram showing the relationship between the size and position of the movable coil and the detection coil.

[0021] Fig.11 It is an explanatory diagram of the effects of the first embodiment.

[0022] Fig.12 : is a graph showing the relationship between the center distance ratio and the speed variation amount in the second embodiment.

[0023] Fig.13 It is a schematic diagram of a keyboard instrument in a modified example.

[0024] Fig.14 It is a schematic diagram of a pedal mechanism in a modified example.

[0025] Fig.15 Schematic diagram showing the relationship between the size and position of the movable coil and the detection coil in a modified example.

[0026] Fig.16 It is a schematic diagram showing the relationship between the size and position of the movable coil and the detection coil in a modified example.

[0027] Fig.17 It is a schematic diagram showing the relationship between the size and position of the movable coil and the detection coil in a modified example.

[0028] Description of Reference Numerals

[0029] 100: keyboard instrument, 10: keyboard unit, 12: keyboard, 14: key, 18: supporting structure, 20: driving mechanism, 21: transmission mechanism, 22: hammer mechanism, 221: hammer handle, 222: hammer part, 223: holding member, 30: detection system, 31: magnetic sensor, 32: detected part, 33: signal generating part, 35: driving circuit, 37: movable substrate, 38: fixed substrate, 40: control system, 41: control device, 42: storage device, 43: A / D converter, 44: sound source device, 50: sound playback system, 60: Moving coil, 61: first part, 62: second part, 70: detection coil, 73: third part, 74: fourth part, 76: connecting wiring, 90: pedal mechanism, 91: pedal, 92: supporting member, 93: elastic body, 321: capacitor element, 331: input terminal, 332: output terminal, 333: resistor element, 334, 335: capacitor element, 351: supply circuit, 352: output circuit, 371, 372, 381, 382: conductive pattern, 611, 612, 621, 622, 731, 732, 741, 742: winding part. DETAILED DESCRIPTION

[0030] A: First Implementation

[0031] Figure 11 is a block diagram illustrating the structure of a keyboard musical instrument 100 according to the first embodiment of the present disclosure. The keyboard musical instrument 100 is an electronic musical instrument (specifically, an electronic piano) including a keyboard unit 10 , a detection system 30 , a control system 40 , and a sound emitting system 50 .

[0032] The keyboard unit 10 includes a keyboard 12. The keyboard 12 is composed of a plurality of keys 14 (white keys and black keys) corresponding to different pitches. The plurality of keys 14 are arranged along the X-axis. The X-axis is an axis extending in the lateral direction of the user in a horizontal plane. Each key 14 is displaced according to an operation for playing performed by the user (hereinafter referred to as a "playing operation"). The playing operation performed by the user includes, for example, touching the key and releasing the key. The detection system 30 detects the playing operation performed by the user.

[0033] The control system 40 generates a sound (audio) signal V corresponding to the result of the detection based on the detection system 30. The sound signal V is a signal representing the waveform of the musical sound corresponding to the performance operation. In addition, the control system 40 can also be configured separately from the keyboard instrument 100. For example, a general-purpose information processing device such as a smart phone, a tablet terminal or a personal computer can also be used as the control system 40.

[0034] The sound reproduction system 50 produces the musical sound represented by the sound signal V. For example, a single or multiple speakers, or a headphone (headphone) (earphone) worn on the user's head is used as the sound reproduction system 50. In addition, the sound reproduction system 50 that is separate from the keyboard instrument 100 can also be connected to the keyboard instrument 100 by wire or wirelessly.

[0035] Figure 2 1 is a side view illustrating a specific structure of the keyboard unit 10. Figure 2 , the structure of an arbitrary key 14 of the keyboard 12 is illustrated. Each key 14 of the keyboard 12 is supported by a supporting structure 18 with a balancing pin 16 as a fulcrum. The supporting structure 18 is a structure (frame) that supports each element of the keyboard instrument 100. The front end of the key 14 is displaced in the vertical direction according to the performance operation performed by the user.

[0036] The keyboard unit 10 includes a plurality of drive mechanisms 20 corresponding to different keys 14 in addition to the keyboard 12. Each drive mechanism 20 is an action mechanism that is actuated in accordance with a performance operation performed by a user. The drive mechanism 20 includes a transmission mechanism 21 and a hammer mechanism 22.

[0037] The transmission mechanism 21 is a mechanism for transmitting the displacement of each key 14 in conjunction with the performance operation to the hammer mechanism 22. Specifically, the transmission mechanism 21 is composed of mechanical elements such as a wippen or a jack.

[0038] The hammer mechanism 22 includes a hammer handle 221, a hammer 222, and a retaining member 223. The hammer handle 221 is a cylindrical long structure. The hammer 222 is a metal weight that allows the user to feel a moderate sense of weight during the performance operation. The retaining member 223 is a structure fixed to the hammer handle 221. The transmission mechanism 21 rotates the hammer mechanism 22 in conjunction with the displacement of the key 14. That is, the hammer mechanism 22 is a movable member that can be displaced according to the performance operation performed by the user.

[0039] Figure 3 3 is a block diagram illustrating the structure of the detection system 30 and the control system 40. The detection system 30 includes a plurality of magnetic sensors 31 corresponding to different drive mechanisms 20 and a drive circuit 35 for driving each of the plurality of magnetic sensors 31. The magnetic sensor 31 corresponding to each drive mechanism 20 is a sensor for detecting the position of the hammer mechanism 22 of the drive mechanism 20. Each of the plurality of magnetic sensors 31 includes a detected portion 32 and a signal generating portion 33. That is, a set of the detected portion 32 and the signal generating portion 33 is provided for each hammer mechanism 22.

[0040] Figure 4 : is a circuit diagram illustrating the electrical structure of an arbitrary magnetic sensor 31. The detected part 32 is a resonant circuit including a capacitor element 321 and a movable coil 60. One end of the movable coil 60 is connected to one end of the capacitor element 321, and the other end of the movable coil 60 is connected to the other end of the capacitor element 321. The movable coil 60 is an example of a "first coil".

[0041] The signal generating unit 33 is a resonant circuit including an input terminal 331, an output terminal 332, a resistor 333, a detection coil 70, a capacitor 334, and a capacitor 335. One end of the resistor 333 is connected to the input terminal 331, and the other end of the resistor 333 is connected to one end of the capacitor 334 and one end of the detection coil 70. The other end of the detection coil 70 is connected to the output terminal 332 and one end of the capacitor 335. The other end of the capacitor 334 and the other end of the capacitor 335 are grounded (Gnd). The resonant frequency of the signal generating unit 33 and the resonant frequency of the detected unit 32 are set to equal frequencies. However, the resonant frequency of the signal generating unit 33 and the resonant frequency of the detected unit 32 may also be different. The detection coil 70 is an example of a "second coil".

[0042] like Figure 2As shown in the example, a plurality of detected parts 32 are respectively provided on a movable substrate 37. The movable substrate 37 is a wiring substrate independently provided for each key 14. Therefore, a plurality of detected parts 32 are arranged in the direction of the X axis. The movable substrate 37 is supported by the aforementioned holding member 223. That is, the detected part 32 (movable coil 60) is provided on the hammer mechanism 22. Therefore, the movable coil 60 is displaced according to the playing operation performed by the user.

[0043] On the other hand, a plurality of signal generating units 33 are provided on a fixed substrate 38. The fixed substrate 38 is a wiring substrate extending in the direction of the X-axis over a plurality of keys 14. A plurality of signal generating units 33 are arranged in the direction of the X-axis. The fixed substrate 38 is fixed to the supporting structure 18. Therefore, each detection coil 70 does not displace when a performance operation is generated, while each movable coil 60 is displaced in conjunction with the performance operation.

[0044] The movable coil 60 and the detection coil 70 are disposed opposite to each other with a gap therebetween. As described above, the movable coil 60 is provided on the rotatable hammer mechanism 22, and the detection coil 70 is fixed to the support structure 18. Therefore, the distance between the movable coil 60 and the detection coil 70 changes in conjunction with the playing operation performed by the user. Figure 4 The driving circuit 35 generates a detection signal D corresponding to the distance between the movable coil 60 and the detection coil 70 .

[0045] Figure 5 3 is a block diagram illustrating a specific structure of the driving circuit 35. The driving circuit 35 includes a supply circuit 351 and an output circuit 352. The supply circuit 351 supplies a driving signal S to an input terminal 331 in each of the plurality of signal generating units 33. For example, the supply circuit 351 is a demultiplexer that supplies the driving signal S to each of the plurality of signal generating units 33 in a time-division manner. The driving signal S is a signal whose level changes periodically. For example, a periodic signal of an arbitrary waveform such as a sine wave or a rectangular wave is used as the driving signal S. The frequency of the driving signal S is sufficiently short compared to the length of time during which the driving signal S is supplied to one signal generating unit 33. In addition, the frequency of the driving signal S is set to a frequency that is substantially equal to the resonant frequency of the signal generating unit 33 and the detected unit 32.

[0046] The drive signal S is supplied to the detection coil 70 via the input terminal 331 and the resistor element 333. A magnetic field is generated in the detection coil 70 by the supply of the drive signal S. An induced current is generated in the movable coil 60 of the detected portion 32 by electromagnetic induction caused by the magnetic field generated in the detection coil 70. That is, a magnetic field in a direction that cancels out the change in the magnetic field of the detection coil 70 is generated in the movable coil 60. The magnetic field generated in the movable coil 60 changes depending on the distance between the movable coil 60 and the detection coil 70. Therefore, a detection signal d whose amplitude varies depending on the distance between the movable coil 60 and the detection coil 70 is output from the output terminal 332 of the signal generating portion 33. The detection signal d is a periodic signal whose level varies at the same frequency as the drive signal S.

[0047] Figure 5 The output circuit 352 is a multiplexer that generates a detection signal D by arranging the detection signals d sequentially outputted from each of the plurality of signal generating units 33 on a time axis. That is, the detection signal D is a periodic signal whose amplitude varies according to the distance between the movable coil 60 and the detection coil 70. As described above, the distance between the movable coil 60 and the detection coil 70 depends on the position of the hammer mechanism 22, and thus the detection signal D is expressed as a signal corresponding to the position of each of the plurality of hammer mechanisms 22.

[0048] As described above, the detection system 30 of the first embodiment generates a detection signal D corresponding to the distance between the movable coil 60 and the detection coil 70. The detection signal D generated by the detection system 30 is supplied to the control system 40. In addition, the detection signal D generated by the output circuit 352 and then rectified (half-wave rectification or full-wave rectification) and smoothed may be supplied to the control system 40.

[0049] Figure 3 The control system 40 generates a sound signal V corresponding to the detection signal D. The control system 40 is implemented by a computer system including a control device 41, a storage device 42, an A / D converter 43, and a sound source device 44. In addition, the control system 40 may be implemented by a single device or by a plurality of devices that are separately configured.

[0050] The control device 41 is composed of a single or multiple processors that control various elements of the keyboard instrument 100. Specifically, the control device 41 is composed of one or more processors such as a CPU (Central Processing Unit), an SPU (Sound Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or an ASIC (Application Specific Integrated Circuit).

[0051] The storage device 42 is a single memory or multiple memories that store programs executed by the control device 41 and data used by the control device 41. The storage device 42 is composed of a known recording medium such as a magnetic recording medium or a semiconductor recording medium. In addition, the storage device 42 may be composed of a combination of multiple recording media. In addition, a removable recording medium that can be attached to and detached from the keyboard instrument 100 or an external recording medium (such as an online storage) that can communicate with the keyboard instrument 100 may be used as the storage device 42.

[0052] The A / D converter 43 converts the detection signal D supplied from the detection system 30 from analog to digital. The control device 41 analyzes the detection signal D after the conversion based on the A / D converter 43 to analyze the positions of the respective hammer mechanisms 22 .

[0053] The sound source device 44 generates a sound signal V representing the sound instructed by the control device 41. The control device 41 instructs the sound source device 44 to generate a musical sound corresponding to the detection signal D. For example, the sound source device 44 is instructed to generate a musical sound having a sound characteristic (such as sound quality or volume) corresponding to the detection signal D. Thus, a sound signal V representing a musical sound corresponding to the performance operation performed by the user is generated. In addition, the control device 41 may also realize the function of the sound source device 44 by executing a program stored in the storage device 42.

[0054] Figure 6 It is a top view of the detection portion 32 . Figure 7 yes Figure 6 A cross-sectional view of the line VII-VII in FIG. Figure 6 as well as Figure 7The diagram shows three mutually orthogonal axes (X-axis, Y-axis, and Z-axis). As mentioned above, the X-axis is an axis along the arrangement of the multiple keys 14 (i.e., the lateral direction). The Y-axis is an axis along the long side direction of the hammer mechanism 22. The Z-axis is an axis orthogonal to the XY plane. The Y-axis is an example of a "first axis" and the X-axis is an example of a "second axis". In the following, the situation of observing an object with a line of sight along the Z-axis will be described as "looking down".

[0055] As described above, the detected portion 32 is provided on the movable substrate 37. The movable substrate 37 is a hard wiring substrate formed of an insulating material. The movable substrate 37 includes a first surface F1 and a second surface F2. The first surface F1 and the second surface F2 are surfaces on opposite sides to each other. The first surface F1 is a surface of the movable substrate 37 that is opposite to the signal generating portion 33, and the second surface F2 is a surface of the movable substrate 37 that is close to the hammer mechanism 22. A capacitor element 321 is mounted on the first surface F1.

[0056] A conductive pattern 371 is formed on the first surface F1 . On the other hand, a conductive pattern 372 is formed on the second surface F2 . The conductive pattern 371 and the conductive pattern 372 are formed by patterning a conductive film covering the movable substrate 37 , for example.

[0057] The movable coil 60 includes a first portion 61 and a second portion 62. The first portion 61 and the second portion 62 are arranged along the Y-axis direction (ie, the longitudinal direction of each key 14). Specifically, the first portion 61 is located in the positive direction of the Y-axis from the second portion 62.

[0058] The first part 61 is formed by stacking the winding part 611 and the winding part 612. The second part 62 is formed by stacking the winding part 621 and the winding part 622. The winding part 611 and the winding part 621 are included in the conductive pattern 371 of the first surface F1, and are formed into a spiral shape rotating from the inside to the outside in a clockwise direction when viewed from above. On the other hand, the winding part 612 and the winding part 622 are included in the conductive pattern 372 of the second surface F2, and are formed into a spiral shape rotating from the inside to the outside in a counterclockwise direction when viewed from above. A capacitor element 321 is provided between the winding part 611 and the winding part 621, and the winding part 612 and the winding part 622 are connected to each other on the second surface F2.

[0059] The center of the winding portion 611 and the center of the winding portion 612 are connected to each other via the conduction hole H1. Similarly, the center of the winding portion 621 and the center of the winding portion 622 are connected to each other via the conduction hole H2. The conduction hole H1 and the conduction hole H2 are through holes formed in the movable substrate 37.

[0060] As from Figure 6As can be understood, when the current in the first direction α1 flows through the winding portion 611, the current in the first direction α1 also flows through the winding portion 612. In addition, when the current in the first direction α1 flows through the winding portion 611, the current in the second direction α2 opposite to the first direction α1 flows through the winding portion 621 and the winding portion 622. That is, if the induced current is generated in the movable coil 60 by the electromagnetic induction of the magnetic field generated by the detection coil 70, as shown in FIG. Figure 7 As illustrated, magnetic fields in opposite directions are generated in the first portion 61 and the second portion 62 .

[0061] Figure 8 It is a top view of the signal generating unit 33 . Fig. 9 yes Figure 8 A cross-sectional view of the line IX-IX in FIG. Figure 8 as well as Fig. 9 It is shown in Figure 6 as well as Figure 7 In addition, the angle between the movable substrate 37 and the fixed substrate 38 changes according to the rotation of the hammer mechanism 22, but in the following description, for convenience, it is assumed that the movable substrate 37 and the fixed substrate 38 are substantially parallel to each other, thereby making the three axes common between the movable substrate 37 and the fixed substrate 38.

[0062] As described above, the signal generating unit 33 is provided on the fixed substrate 38. The fixed substrate 38 includes a third surface F3 and a fourth surface F4. The third surface F3 and the fourth surface F4 are surfaces on opposite sides to each other. The third surface F3 is a surface of the fixed substrate 38 that is opposite to the movable substrate 37. On the third surface F3, a resistor element 333, a capacitor element 334, and a capacitor element 335 are mounted for each signal generating unit 33.

[0063] A conductive pattern 381 is formed on the third surface F3 of the fixed substrate 38. The conductive pattern 381 includes an input terminal 331, an output terminal 332, and a ground terminal 336 (Gnd) for each of the plurality of signal generating units 33. On the other hand, a conductive pattern 382 is formed on the fourth surface F4. The conductive pattern 381 and the conductive pattern 382 are formed, for example, by patterning a conductive film covering the fixed substrate 38.

[0064] The detection coil 70 includes a third portion 73 and a fourth portion 74. The third portion 73 and the fourth portion 74 are arranged in the direction of the Y-axis (i.e., the long side direction of each key 14). Specifically, the third portion 73 is located in the positive direction of the Y-axis from the perspective of the fourth portion 74. The third portion 73 of the detection coil 70 is opposite to the first portion 61 of the movable coil 60 corresponding to the detection coil 70. That is, from the perspective of the Z-axis, the first portion 61 and the third portion 73 overlap with each other. The fourth portion 74 of the detection coil 70 is opposite to the second portion 62 of the movable coil 60 corresponding to the detection coil 70. That is, from the perspective of the Z-axis, the second portion 62 and the fourth portion 74 overlap with each other.

[0065] The third portion 73 is formed by stacking the winding portion 731 and the winding portion 732. The fourth portion 74 is formed by stacking the winding portion 741 and the winding portion 742. The winding portion 731 and the winding portion 741 are included in the conductive pattern 381 on the third surface F3, and are formed into a spiral shape rotating clockwise from the inside to the outside in a plan view. On the other hand, the winding portions 732 and 742 are included in the conductive pattern 382 on the fourth surface F4, and are formed into a spiral shape rotating counterclockwise from the inside to the outside in a plan view.

[0066] The center of the winding portion 731 and the center of the winding portion 732 are connected to each other via the conduction hole H3. Similarly, the center of the winding portion 741 and the center of the winding portion 742 are connected to each other via the conduction hole H4. The conduction hole H3 and the conduction hole H4 are through holes formed in the fixed substrate 38.

[0067] The winding part 731 is connected to the input terminal 331 via the resistor 333, and the winding part 741 is connected to the output terminal 332. Furthermore, the capacitor 334 is provided between the resistor 333 and the ground terminal 336, and the capacitor 335 is provided between the output terminal 332 and the ground terminal 336.

[0068] The signal generating section 33 includes a connection wiring 76 in the conductive pattern 381. The winding section 732 of the third portion 73 is electrically connected to one end of the connection wiring 76 via the via Ha, and the winding section 742 of the fourth portion 74 is electrically connected to the other end of the connection wiring 76 via the via Hb. That is, the winding section 732 and the winding section 742 are electrically connected via the connection wiring 76.

[0069] As from Figure 8 As can be understood, when the current in the first direction α1 flows through the winding portion 731, the current in the first direction α1 also flows through the winding portion 732. In addition, when the current in the first direction α1 flows through the winding portion 731, the current in the second direction α2 opposite to the first direction α1 flows through the winding portion 741 and the winding portion 742. That is, when the driving signal S is supplied to the detection coil 70, as shown in FIG. Fig. 9 As shown, magnetic fields in opposite directions are generated in the third portion 73 and the fourth portion 74. Since the drive signal S is a signal whose signal level is periodically reversed, the first direction α1 and the second direction α2 are periodically reversed while maintaining the relationship of opposite directions.

[0070] Fig.10 Schematic diagram showing the relationship between the size and position of the movable coil 60 and the detection coil 70. Fig.10 , the outer shapes of the first portion 61 and the second portion 62 of the movable coil 60 and the outer shapes of the third portion 73 and the fourth portion 74 of the detection coil 70 are described together. Fig.10 The third portion 73 and the fourth portion 74 are shown in the figure as being adjacent to each other, but in reality, Figure 8 As shown in the example of FIG. 7 , the third portion 73 and the fourth portion 74 are adjacent to each other with a gap. However, the third portion 73 and the fourth portion 74 may also be Fig.10 As shown in the example, they are adjacent to each other without any spacing.

[0071] like Fig.10 As illustrated, when the movable substrate 37 and the fixed substrate 38 are substantially parallel, the first portion 61 and the third portion 73 overlap each other in a plan view, and the second portion 62 and the fourth portion 74 overlap each other in a plan view.

[0072] Fig.10 The outer dimension Da1 is the dimension of the first portion 61 in the direction of the Y axis. Fig.10 The outer dimension Da2 is the dimension of the second portion 62 in the direction of the Y axis. When focusing on the closed figure defined by the outline of the first portion 61, the outer dimension Da1 of the first portion 61 means the dimension (size) of the closed figure in the direction of the Y axis, and is also referred to as the maximum value of the dimension of the first portion 61 in the direction of the Y axis. The outline (closed figure) of the first portion 61 is the outermost periphery in the winding portion 611 or the winding portion 612. The above focuses on the first portion 61, but the outer dimension Da2 of the second portion 62 is also defined in the same way.

[0073] In the first embodiment, the outer dimension Da1 of the first portion 61 and the outer dimension Da2 of the second portion 62 are equal. Therefore, in the following description, the outer dimension Da1 and the outer dimension Da2 are sometimes referred to as the outer dimension Da (Da = Da1 = Da2). In addition, the outer dimension Da1 is an example of the "first outer dimension", and the outer dimension Da2 is an example of the "second outer dimension".

[0074] Fig.10The outer dimension Db3 is the dimension of the third portion 73 in the direction of the Y axis. Fig.10 The outer dimension Db4 is the dimension of the fourth portion 74 in the direction of the Y axis. When focusing on the closed figure defined by the outline of the third portion 73, the outer dimension Db3 of the third portion 73 means the dimension (size) of the closed figure in the direction of the Y axis, and is also referred to as the maximum value of the dimension of the third portion 73 in the direction of the Y axis. The outline (closed figure) of the third portion 73 is the outermost peripheral edge in the winding portion 731 or the winding portion 732. The above focuses on the third portion 73, but the outer dimension Db4 of the fourth portion 74 is also defined in the same manner.

[0075] In the first embodiment, the outer dimension Db3 of the third portion 73 is equal to the outer dimension Db4 of the fourth portion 74. Therefore, in the following description, the outer dimension Db3 and the outer dimension Db4 are sometimes referred to as the outer dimension Db (Db = Db3 = Db4). In addition, the outer dimension Db3 is an example of the "third outer dimension", and the outer dimension Db4 is an example of the "fourth outer dimension".

[0076] The outer dimension Da1 of the first portion 61 is less than the outer dimension Db3 of the third portion 73 (Da1≤Db3). In the first embodiment, the outer dimension Da1 is less than the outer dimension Db3 (Da1<Db3). In addition, the outer dimension Da1 is 0.5 times or more of the outer dimension Db3 (0.5Db3≤Da1≤Db3).

[0077] Similarly, the outer dimension Da2 of the second portion 62 is less than the outer dimension Db4 of the fourth portion 74 (Da2≤Db4). In the first embodiment, the outer dimension Da2 is less than the outer dimension Db4 (Da2<Db4). In addition, the outer dimension Da2 is more than 0.5 times the outer dimension Db4 (0.5Db4≤Da2≤Db4).

[0078] As described above, in the first embodiment, the outer dimension Da1 is equal to the outer dimension Da2, and the outer dimension Db3 is equal to the outer dimension Db4. Therefore, the outer dimension Da of each of the first portion 61 and the second portion 62 is less than the outer dimension Db of each of the third portion 73 and the fourth portion 74 (Da≤Db). Specifically, the outer dimension Da is lower than the outer dimension Db (Da<Db). The outer dimension Da in the first embodiment is more than 0.5 times the outer dimension Db (0.5Db≤Da≤Db). In addition, the outer dimension Da and the outer dimension Db may be equal values.

[0079] Fig.10The center-to-center distance La is the distance between the center O1 of the first portion 61 and the center O2 of the second portion 62 in the Y-axis direction. The center O1 of the first portion 61 means the center (center of gravity) of the closed figure defined by the contour line of the first portion 61. In the first embodiment, the via H1 corresponds to the center O1. Similarly, the via H2 of the second portion 62 corresponds to the center O2. The center-to-center distance La is an example of the “first distance”.

[0080] Fig.10 The center-to-center distance Lb is the distance between the center O3 of the third portion 73 and the center O4 of the fourth portion 74 in the direction of the Y axis. The center O3 of the third portion 73 means the center (center of gravity) of the closed figure defined by the contour line of the third portion 73. In the first embodiment, the via H3 corresponds to the center O3. Similarly, the via H4 of the fourth portion 74 corresponds to the center O4. The center-to-center distance Lb is an example of the “second distance”.

[0081] In the first embodiment, the center distance La between the first portion 61 and the second portion 62 exceeds the center distance Lb between the third portion 73 and the fourth portion 74 (La>Lb). The center distance La is not more than twice the center distance Lb (Lb<La≤2Lb).

[0082] The center O1 of the first portion 61, the center O2 of the second portion 62, the center O3 of the third portion 73, and the center O4 of the fourth portion 74 are located on a straight line parallel to the Y axis. The center O3 of the third portion 73 and the center O4 of the fourth portion 74 are located between the center O1 of the first portion 61 and the center O2 of the second portion 62 in the direction of the Y axis. Specifically, the center O3 is located between the center O1 and the center O4, and the center O4 is located between the center O2 and the center O3.

[0083] The center O1 of the first portion 61 and the center O3 of the third portion 73 are located within a range B13 where the first portion 61 and the third portion 73 overlap in a plan view. Fig.10 , edge S1 in the first portion 61 located in the negative direction of the Y axis and edge S3 in the third portion 73 located in the positive direction of the Y axis are shown. Range B13 is the range between edge S1 and edge S3. That is, center O1 and center O3 are located between edge S1 and edge S3. In addition, the case where center O1 or center O3 is located on the line of edge S1 or edge S3 also corresponds to "within range B13".

[0084] The center O2 of the second portion 62 and the center O4 of the fourth portion 74 are located within a range B24 where the second portion 62 and the fourth portion 74 overlap in a plan view. The range B24 is a range between an edge S2 of the second portion 62 located in the positive direction of the Y axis and an edge S4 of the fourth portion 74 located in the negative direction of the Y axis. That is, the center O2 and the center O4 are located between the edge S2 and the edge S4. In addition, the case where the center O2 or the center O4 is located on the line of the edge S2 or the edge S4 also corresponds to "within the range B24".

[0085] As described above, in the first embodiment, the center distance La and the center distance Lb are set so that the center O1 and the center O3 are located within the range B13 and the center O2 and the center O4 are located within the range B24. According to the above structure, it is easier to make the first part 61 generate an induced current based on the magnetic field generated in the third part 73 than in a structure in which one or both of the center O1 of the first part 61 and the center O3 of the third part 73 are located outside the range B13. Similarly, it is easier to make the second part 62 generate an induced current based on the magnetic field generated in the fourth part 74 than in a structure in which one or both of the center O2 of the second part 62 and the center O4 of the fourth part 74 are located outside the range B24. Therefore, it is possible to generate a detection signal D that reflects the distance between the movable coil 60 and the detection coil 70 with high accuracy.

[0086] The portion P1 of the first portion 61 located on the side opposite to the second portion 62 is located outside the third portion 73 in a plan view. That is, the portion P1 is a portion of the first portion 61 located closer to the positive direction of the Y axis than the edge S3 of the third portion 73. That is, the portion P1 of the first portion 61 protrudes from the edge S3 in the positive direction of the Y axis. As described above, the first portion 61 of the first embodiment partially overlaps with the third portion 73 in a plan view.

[0087] The portion P2 of the second portion 62 located on the side opposite to the first portion 61 is located outside the fourth portion 74 in a plan view. That is, the portion P2 is a portion of the second portion 62 located closer to the negative direction of the Y axis than the edge S4 of the fourth portion 74. That is, the portion P2 of the second portion 62 protrudes from the edge S4 in the negative direction of the Y axis. As described above, the second portion 62 of the first embodiment partially overlaps with the fourth portion 74 in a plan view.

[0088] Fig.11 The results are as follows: the detection characteristics of the detection system 30 were evaluated for each of a plurality of test samples after varying the center-to-center distance La. Fig.11 , the detection error characteristics are shown graphically for each test sample.

[0089] The detection error characteristic is the relationship between the position error E (horizontal axis) and the measurement speed Q (vertical axis). The position error E is the error between the positions of the movable coil 60 and the detection coil 70 in the direction of the Y axis. That is, the value of the position error E of 0 means that the movable coil 60 is at the designed target position relative to the detection coil 70 in the direction of the Y axis. The state in which the movable coil 60 is offset in the negative direction of the Y axis relative to the target position is represented by a negative number of the position error E, and the state in which the movable coil 60 is offset in the positive direction of the Y axis relative to the target position is represented by a positive number of the position error E.

[0090] The measured speed Q is the speed of the movable coil 60 determined by analyzing the detection signal D generated by the detection system 30 when the movable coil 60 is moved at a predetermined speed. The measured speed Q is standardized (normalized) so that the measured speed Q becomes 0 when the position error E is 0.

[0091] exist Fig.11 The speed variation Δ is shown in the detection error characteristic of FIG. The speed variation Δ is the absolute value of the difference between the maximum value and the minimum value of the measured speed Q within the range R of values ​​assumed for the position error E. That is, the speed variation Δ is an indicator showing how the measured speed Q determined by the detection signal D changes relative to the position error (position error E) when there is a position error between the movable coil 60 and the detection coil 70. The range R means the allowable range of the position error E.

[0092] That is, when the speed variation Δ is large, even when there is a small error in the positions of the movable coil 60 and the detection coil 70, the measured speed Q will vary greatly. On the other hand, when the speed variation Δ is small, even when there is an error in the positions of the movable coil 60 and the detection coil 70, the error in the measured speed Q can be suppressed. As understood from the above description, in order to suppress the reduction in detection accuracy caused by the error in the positions of the movable coil 60 and the detection coil 70, it is necessary to suppress the speed variation Δ to a small value.

[0093] Fig.11 The reference sample is a sample in which the center O1 of the first portion 61 coincides with the center O3 of the third portion 73, and the center O2 of the second portion 62 coincides with the center O4 of the fourth portion 74. That is, in the reference sample, the center-to-center distance La coincides with the center-to-center distance Lb.

[0094] On the other hand, in test samples #1 to #3, the center distance La between the first portion 61 and the second portion 62 is gradually increased from the reference sample while the center distance Lb between the third portion 73 and the fourth portion 74 is fixed.

[0095] like Fig.11 As shown in the example, the speed variation Δ of the test samples #1 to #3 is lower than the speed variation Δ of the reference sample. Fig.10 The structure can be evaluated as being able to suppress the speed variation Δ. That is, it is possible to suppress the reduction in detection accuracy due to the positional error between the movable coil 60 and the detection coil 70 in the Y-axis direction.

[0096] In addition, test sample #1 is a method in which the entire first portion 61 overlaps with the third portion 73, and the entire second portion 62 overlaps with the fourth portion 74. On the other hand, test sample #2 and test sample #3 are a method in which the first portion 61 includes a portion P1 located outside the third portion 73, and the second portion 62 includes a portion P2 located outside the fourth portion 74. The speed variation Δ of test sample #2 and test sample #3 is lower than the speed variation Δ of the reference sample and test sample #1. Therefore, according to the structure in which the first portion 61 includes the portion P1 and the structure in which the second portion 62 includes the portion P2, it can be evaluated that the speed variation Δ can be suppressed. That is, according to the first embodiment, the reduction in detection accuracy caused by the error in the position of the movable coil 60 and the detection coil 70 in the direction of the Y axis can be suppressed.

[0097] like Fig.10 As illustrated, the size (i.e., width) Wb of the detection coil 70 in the direction of the X-axis exceeds the size Wa of the movable coil 60 in the direction of the X-axis (Wb>Wa). According to the above structure, even when an error (lateral offset) occurs in the position of the movable coil 60 and the detection coil 70 in the direction of the X-axis, the area of ​​the overlapping portion of the movable coil 60 and the detection coil 70 does not change. Therefore, it is possible to suppress the error in the output characteristics of the detection signal D caused by the error in the position of the movable coil 60 and the detection coil 70 in the direction of the X-axis. That is, it is possible to suppress the reduction in detection accuracy caused by the error in the position of the movable coil 60 and the detection coil 70 in the direction of the X-axis.

[0098] B: Second Implementation

[0099] In the following embodiments, the same reference numerals as those in the first embodiment are used for elements having the same functions as those in the first embodiment, and detailed descriptions thereof are appropriately omitted.

[0100] In the second embodiment, attention is paid to the center-to-center distance ratio C. The center-to-center distance ratio C is a dimensionless quantity expressed by the following mathematical formula (1).

[0101] C=(La-Lb) / Db (1)

[0102] As can be understood from the mathematical formula (1), the center distance ratio C is a value obtained by dividing the difference (La-Lb) between the distance La between the center O1 of the first portion 61 and the center O2 of the second portion 62 and the distance Lb between the center O3 of the third portion 73 and the center O4 of the fourth portion 74 by the outer dimension Db3 of the third portion 73 or the outer dimension Db4 of the fourth portion 74 in the Y-axis direction. That is, the center distance ratio C means the ratio of the difference (La-Lb) between the center distance La and the center distance Lb to the outer dimension Db of the third portion 73 or the fourth portion 74.

[0103] In addition, the distance between the center O1 of the first portion 61 and the center O3 of the third portion 73 and the distance between the center O2 of the second portion 62 and the center O4 of the fourth portion 74 are expressed as (La-Lb) / 2. Therefore, the center-to-center distance ratio C is also expressed as a value obtained by dividing the distance (La-Lb) / 2 between the center O1 (O2) and the center O3 (O4) by Db / 2, which is half of the outer dimension Db ({(La-Lb) / 2} / {Db / 2}).

[0104] Fig.12 The results are obtained by evaluating the detection characteristics of the detection system 30 for each of a plurality of test samples after varying the center-to-center distance ratio C. Fig.12 , the relationship between the center distance ratio C (horizontal axis) and the speed change Δ (vertical axis) are illustrated for multiple test samples. The multiple test samples in the second embodiment include samples in which the relationship between the size and position of the movable coil 60 and the detection coil 70 satisfies the conditions illustrated in the first embodiment, as well as samples that do not satisfy the conditions.

[0105] As from Fig.12 As can be understood, there is a correlation between the center distance ratio C and the speed variation Δ. Specifically, the speed variation Δ decreases when the center distance ratio C increases from 0, and the speed variation Δ increases when the center distance ratio C increases within a range exceeding a predetermined value (for example, a value near 0.6). That is, the speed variation Δ has a general tendency to be the minimum value (extreme value) when the center distance ratio C takes a value near 0.6.

[0106] Focus is placed on a reference sample that serves as a reference for the velocity variation Δ. Similar to the first embodiment, the reference sample is a sample in which the center O1 of the first portion 61 coincides with the center O3 of the third portion 73, and the center O2 of the second portion 62 coincides with the center O4 of the fourth portion 74. That is, in the reference sample, the center-to-center distance La coincides with the center-to-center distance Lb. The velocity variation Δ of the reference sample is 9.28.

[0107] As from Fig.12As understood, the range of the center distance ratio C for which the velocity variation Δ is lower than the value of the reference sample (Δ=9.28) is greater than 0 and less than 1. In view of the results of the above studies, in the second embodiment, the size and position of each element of the movable coil 60 and the detection coil 70 are selected in such a way that the center distance ratio C becomes greater than 0 and less than 1 (0≤C≤1). The structure in which the center distance ratio C is greater than 0 is a structure in which the center distance La between the first part 61 and the second part 62 is greater than the center distance Lb between the third part 73 and the fourth part 74 (La≥Lb). In addition, the structure in which the center distance ratio C is less than 1 is a structure in which the difference (La-Lb) between the center distance La and the center distance Lb is less than the outer dimension Db of the third part 73 or the fourth part 74.

[0108] In the second embodiment, the size and position of each element of the movable coil 60 and the detection coil 70 are selected so that the center distance ratio C is greater than 0 and less than 1 (0<C<1). That is, the center distance La exceeds the center distance Lb and the difference therebetween (La-Lb) is less than the outer dimension Db.

[0109] In the second embodiment, the center-to-center distance ratio C satisfies the above conditions, so the speed variation Δ is lower than that of the reference sample. Therefore, according to the second embodiment, the decrease in detection accuracy caused by the position error of the movable coil 60 and the detection coil 70 in the Y-axis direction can be suppressed compared with the reference sample.

[0110] In the above description, comparison with a reference sample is assumed, but in actual products, it is expected that the speed variation Δ is a value less than 5. Fig.12 As understood, the range of the center distance ratio C for which the velocity variation Δ becomes less than 5 is greater than or equal to 0.3 and less than or equal to 0.85. In view of the above research results, in the second embodiment, the size and position of each element of the movable coil 60 and the detection coil 70 are selected so that the center distance ratio C becomes greater than or equal to 0.3 and less than or equal to 0.85 (0.3≤C≤0.85). More specifically, the size and position of each element of the movable coil 60 and the detection coil 70 are selected so that the center distance ratio C exceeds 0.3 and is less than 0.85 (0.3<C<0.85).

[0111] In the second embodiment, the center-to-center distance ratio C satisfies the above conditions, so the speed variation Δ is suppressed to a value less than 5. Therefore, according to the second embodiment, the reduction in detection accuracy caused by the error in the positions of the movable coil 60 and the detection coil 70 in the Y-axis direction can be sufficiently suppressed.

[0112] The relationship between the first embodiment and the second embodiment will be supplemented below. In the first embodiment, the size and position of each element of the movable coil 60 and the detection coil 70 are selected so that the following first condition is satisfied.

[0113] [First condition]

[0114] 1A: The outer dimension Da1 of the first portion 61 in the Y-axis direction is less than or equal to the outer dimension Db3 of the third portion 73 in the Y-axis direction, and the outer dimension Da2 of the second portion 62 in the Y-axis direction is less than or equal to the outer dimension Db4 of the fourth portion 74 in the Y-axis direction.

[0115] 1B: The center-to-center distance La between the center O1 of the first portion 61 and the center O2 of the second portion 62 exceeds the center-to-center distance Lb between the center O3 of the third portion 73 and the center O4 of the fourth portion 74 .

[0116] 1C: The center O3 of the third portion 73 and the center O4 of the fourth portion 74 are located between the center O1 of the first portion 61 and the center O2 of the second portion 62 in the direction of the Y axis.

[0117] On the other hand, in the second embodiment, the size and position of each element of the movable coil 60 and the detection coil 70 are selected so that the following second condition is satisfied.

[0118] [Second condition]

[0119] The center distance ratio C, which is a value obtained by dividing the difference (La-Lb) between the center distance La of the first part 61 and the second part 62 and the center distance Lb of the third part 73 and the fourth part 74 by the outer dimension Db (Db3, Db4) of the third part 73 or the fourth part 74 in the direction of the Y axis, is greater than 0 and less than 1.

[0120] The movable coil 60 and the detection coil 70 may satisfy both the first condition and the second condition, or may satisfy only one of the first condition and the second condition. That is, for example, in the second embodiment, the first condition may not be satisfied. Specifically, in the second embodiment, a method in which the outer dimension Da exceeds the outer dimension Db (a method that does not satisfy condition 1A) is also envisioned.

[0121] C: Deformation

[0122] Specific modified forms added to the above-exemplified forms are exemplified below. Two or more forms arbitrarily selected from the following examples may be appropriately combined within the scope of no contradiction.

[0123] (1) In the above-mentioned embodiments, the detection system 30 detects the displacement of the hammer mechanism 22 . However, as will be exemplified below, the object of detection by the detection system 30 is not limited to the hammer mechanism 22 .

[0124] Fig.13 1 is a schematic diagram focusing on one key 14 of the keyboard instrument 100. Fig.13 As shown, the detected unit 32 is provided on each key 14. For example, a movable coil 60 is provided on the lower surface of each key 14. In addition, the signal generating unit 33 including the detecting coil 70 is provided on the supporting structure 18. The movable coil 60 and the detecting coil 70 face each other.

[0125] Fig.14 1 is a schematic diagram of a pedal mechanism 90 of an exemplary keyboard musical instrument 100. The pedal mechanism 90 includes a pedal 91 operated by a user's foot, a supporting member 92 supporting the pedal 91, and an elastic body 93 applying force to the pedal 91 in the vertical direction upward. In the above structure, the detected portion 32 is provided on the pedal 91. Specifically, a movable coil 60 is provided on the lower surface of the pedal 91. In addition, a signal generating portion 33 including a detection coil 70 is provided on the supporting member 92. The movable coil 60 and the detection coil 70 are opposite to each other.

[0126] In addition, Fig.14 In the embodiment, the pedal mechanism 90 of the keyboard instrument 100 is illustrated, but the same pedal mechanism is also used in the pedal mechanism used in the electric musical instrument such as the electric string instrument (for example, the electric guitar). Fig.14 The pedal mechanism used in electric musical instruments is, for example, an effect pedal operated by a user to adjust various sound effects such as distortion or compressor.

[0127] In addition, in the above-mentioned embodiments, the keyboard instrument 100 is exemplified, but the application of the present disclosure is not limited to the above-mentioned embodiments. For example, when a woodwind instrument (such as a clarinet or a saxophone) or a brass instrument (such as a trumpet or a trombone) is played, the same structure as in the above-mentioned embodiments is used to detect the position of the operating member operated by the user.

[0128] As can be understood from the above examples, the elements in which the movable coil 60 is provided are generally represented as movable components that are displaced according to the performance action. As for the movable components, in addition to the performance operating parts such as the key 14 or the pedal 91 directly operated by the user, it also includes structures such as the hammer mechanism 22 that is displaced in conjunction with the operation of the performance operating parts. However, the movable components in the present disclosure are not limited to components that are displaced according to the performance action. That is, the movable components are generally represented as components that can be displaced regardless of the opportunity for causing the displacement.

[0129] In addition, the movable coil 60 and the detection coil 70 may have position errors in the direction of the Y axis due to assembly errors of the keyboard instrument 100. In the case where errors occur in the positions of the movable coil 60 and the detection coil 70 in the direction of the Y axis, the errors in the output characteristics may become apparent. According to the present disclosure, the velocity variation Δ can be suppressed as described above, so the reduction in detection accuracy caused by the errors in the positions of the movable coil 60 and the detection coil 70 in the direction of the Y axis can be suppressed.

[0130] However, in a structure in which the angle between the movable coil 60 and the detection coil 70 changes during the displacement of the movable coil 60, the error in the output characteristic caused by the error in the position of the movable coil 60 and the detection coil 70 is particularly easy to become obvious. That is, in a structure in which the angle between the movable coil 60 and the detection coil 70 changes, there is a tendency for the speed variation Δ in the detection error characteristic to become large. According to the present disclosure, the speed variation Δ can be suppressed as described above, and therefore it is particularly suitable for a structure in which the movable coil 60 is provided in the hammer mechanism 22 that rotates according to the playing operation, that is, a structure in which the detection system 30 is used in the detection of the position of the hammer mechanism 22.

[0131] (2) In the second embodiment, the combination of the lower limit value (0, 0.3) and the upper limit value (0.85, 1) that define the range of the center distance ratio C is appropriately changed. For example, the center distance ratio C may be a value greater than or equal to 0 and less than or equal to 0.85, or a value greater than or equal to 0.3 and less than or equal to 1.

[0132] (3) In the above-mentioned embodiments, the embodiment in which magnetic fields in opposite directions are generated in the first portion 61 and the second portion 62 of the movable coil 60 is exemplified, but it is also conceivable that magnetic fields in the same direction are generated in the first portion 61 and the second portion 62. That is, currents in the same direction may flow in the first portion 61 and the second portion 62.

[0133] In the above-mentioned embodiments, the third portion 73 and the fourth portion 74 of the detection coil 70 generate magnetic fields in opposite directions, but it is also conceivable that magnetic fields in the same direction are generated in the third portion 73 and the fourth portion 74. That is, currents in the same direction may flow in the third portion 73 and the fourth portion 74.

[0134] (4) In each of the above-mentioned embodiments, the movable coil 60 is composed of two layers of the conductive pattern 371 and the conductive pattern 372, but the structure of the movable coil 60 is not limited to the above examples. For example, the movable coil 60 may also be composed of a single layer or three or more layers. Similarly, the detection coil 70 may also be composed of a single layer or three or more layers.

[0135] (5) In the aforementioned embodiments, the planar shapes of the first portion 61 and the second portion 62 of the movable coil 60 and the third portion 73 and the fourth portion 74 of the detection coil 70 are illustrated as rectangular shapes, but the planar shapes of the movable coil 60 and the detection coil 70 are not limited to the above examples.

[0136] For example, Fig.15 As shown in the example, the first part 61 and the second part 62 of the movable coil 60 may each have a polygonal shape other than a rectangle (e.g., an octagonal shape) in plan view. Similarly, the third part 73 and the fourth part 74 of the detection coil 70 may each have a polygonal shape other than a rectangle (e.g., an octagonal shape) in plan view.

[0137] In addition, if Fig.16 As shown in the example, the first part 61 and the second part 62 of the movable coil 60 may each have a circular shape (e.g., a perfect circle, an ellipse, or an oblong shape) in plan view. Similarly, the third part 73 and the fourth part 74 of the detection coil 70 may each have a circular shape (e.g., a perfect circle, an ellipse, or an oblong shape) in plan view.

[0138] like Fig.17 As shown, the first and second portions 61 and 62 of the movable coil 60 may each be a polygonal shape with a diagonal line along the Y axis. Similarly, the third and fourth portions 73 and 74 of the detection coil 70 may each be a polygonal shape with a diagonal line along the Y axis.

[0139] from Figures 15 to 17 As can be understood from the examples, regardless of the planar shapes of the movable coil 60 and the detection coil 70, the dimensions of the respective parts of the movable coil 60 and the detection coil 70 satisfy the conditions exemplified in the above-mentioned respective embodiments.

[0140] For example, regardless of the planar shape of the movable coil 60, the outer dimension Da1 is the dimension of the first portion 61 in the Y-axis direction, and the outer dimension Da2 is the dimension of the second portion 62 in the Y-axis direction. Similarly, regardless of the planar shape of the detection coil 70, the outer dimension Db3 is the dimension of the third portion 73 in the Y-axis direction, and the outer dimension Db4 is the dimension of the fourth portion 74 in the Y-axis direction. The relationship between the outer dimensions Da (Da1, Da2) and the outer dimensions Db (Db3, Db4) is the same as in the above-mentioned embodiments.

[0141] In addition, regardless of the planar shape of the movable coil 60, the center distance La is the distance between the center O1 of the first part 61 and the center O2 of the second part 62 in the direction of the Y axis. Similarly, regardless of the planar shape of the detection coil 70, the center distance Lb is the distance between the center O3 of the third part 73 and the center O4 of the fourth part 74 in the direction of the Y axis. The relationship between the center distance La and the center distance Lb is the same as in the above-mentioned embodiments. In addition, the appropriate range of the center distance ratio C is the same as that illustrated in the second embodiment.

[0142] Regardless of the planar shapes of the movable coil 60 and the detection coil 70, a portion P1 of the first portion 61 located on the side opposite to the second portion 62 is located outside the third portion 73 in a plan view. Similarly, regardless of the planar shapes of the movable coil 60 and the detection coil 70, a portion P2 of the second portion 62 located on the side opposite to the first portion 61 is located outside the fourth portion 74 in a plan view.

[0143] (6) In the above-mentioned embodiments, the embodiment in which the outer dimension Da1 of the first portion 61 and the outer dimension Da2 of the second portion 62 are equal (Da1=Da2=Da) is exemplified, but the outer dimension Da1 and the outer dimension Da2 may be different. Specifically, the embodiment in which the outer dimension Da1 exceeds the outer dimension Da2 or the outer dimension Da2 exceeds the outer dimension Da1 is also conceivable.

[0144] Similarly, in the above-mentioned embodiments, the embodiment in which the outer dimension Db3 of the third portion 73 and the outer dimension Db4 of the fourth portion 74 are equal (Db3=Db4=Db) is exemplified, but the outer dimension Db3 and the outer dimension Db4 may be different. Specifically, the embodiment in which the outer dimension Db3 exceeds the outer dimension Db4 or the outer dimension Db4 exceeds the outer dimension Db3 is also conceivable.

[0145] In the embodiment where the outer dimension Da1 and the outer dimension Da2 are different, the relationship between the outer dimension Da1 and the outer dimension Db4, and the relationship between the outer dimension Da2 and the outer dimension Db3 are not limited. That is, the embodiment where the outer dimension Da1 is greater than the outer dimension Db4, and the embodiment where the outer dimension Da2 is greater than the outer dimension Db3 are also conceivable. In the embodiment where the outer dimension Db3 and the outer dimension Db4 are different, the relationship between the outer dimension Da1 and the outer dimension Db4, and the relationship between the outer dimension Da2 and the outer dimension Db3 are also not limited.

[0146] (7) In the aforementioned methods, an electronic musical instrument in which the sound source device 44 generates a sound signal V is exemplified, but the aforementioned methods are also applicable to a keyboard instrument such as a natural musical instrument that produces musical sounds from a sound source such as a string. In the keyboard instrument of a natural musical instrument, the hammer part 222 in the aforementioned methods is replaced by a hammer for striking the strings. The aforementioned methods are also applicable to a keyboard instrument having a string striking mechanism such as an automatic piano or a silent piano. In the keyboard instrument exemplified above, a detection system 30 is used to detect the displacement of movable components such as keys 14 or hammer mechanisms 22 (or hammers). The "musical instrument" disclosed in the present invention is a device used in the performance of music, and the "musical instrument" includes both electronic instruments and natural instruments.

[0147] (8) In the above-mentioned embodiments, an upright driving mechanism 20 is exemplified, but the above-mentioned embodiments are also applicable to a keyboard musical instrument having a grand piano-type driving mechanism. In addition, the type of keyboard musical instrument to which the present disclosure is applied is not limited to a piano. The above-mentioned embodiments are also applicable to various keyboard musical instruments such as a celesta or a glockenspiel.

[0148] (9) The term "nth" (n is a natural number) in this application is used only as a convenient identifier (label) to distinguish the elements in the description, and does not have any substantial meaning. Therefore, there is no room for restrictive interpretation of the position of each element or the order of manufacture based on the term "nth".

[0149] D: Notes

[0150] According to the above-exemplified embodiment, for example, the following configuration can be understood.

[0151] [Method A]

[0152] A detection system involved in one method (method A1) of the present disclosure is a detection system that includes a first coil that can be displaced and a second coil that generates a magnetic field by supplying a driving signal, and generates a detection signal corresponding to the distance between the first coil and the second coil, wherein the first coil includes a first part and a second part arranged along a first axis, and the second coil includes a third part opposite to the first part and a fourth part opposite to the second part, a first outer dimension of the first part in the direction of the first axis is less than a third outer dimension of the third part in the direction of the first axis, a second outer dimension of the second part in the direction of the first axis is less than a fourth outer dimension of the fourth part in the direction of the first axis, a first distance between the center of the first part and the center of the second part exceeds a second distance between the center of the third part and the center of the fourth part, and the center of the third part and the center of the fourth part are located between the center of the first part and the center of the second part in the direction of the first axis.

[0153] According to the above method, even when an error (longitudinal offset) occurs in the positions of the first coil and the second coil in the direction of the first axis, an error in the output characteristics of the detection signal (for example, the relationship between the distance between the first coil and the second coil and the signal level of the detection signal) caused by the error is suppressed. That is, it is possible to suppress a decrease in the detection accuracy caused by the error in the positions of the first coil and the second coil in the direction of the first axis.

[0154] The state where the first part and the third part are "opposed" means a state where the central axis of each of the first part and the third part passes through the other. That is, the state where the first part and the third part are "opposed" means a state where a plane orthogonal to the central axis of the first part and a plane orthogonal to the central axis of the third part are opposite to each other, and typically, the state where the central axis of the first part and the central axis of the third part are parallel can be exemplified.

[0155] In addition, it is not necessary for the first part and the third part to be opposite to each other when the first coil is at any position within the movable range. As long as the first part and the third part are opposite to each other when the first coil is at a specific position within the movable range, it can be interpreted that the first part and the third part are "opposed". In addition, it is not necessary for the entirety of the first part and the third part to be opposite to the other, but a part of one of the first part and the third part may be opposite to the other. In addition, in the above description, the focus is on the relationship between the first part and the third part, but the same applies to the relationship between the second part and the fourth part.

[0156] The "outer dimensions" of the first part in the direction of the first axis means the dimension (size) of the closed figure (outer dimensions) in the direction of the first axis when focusing on the closed figure (outer dimensions) defined by the contour line of the first part, and is also referred to as the maximum value of the dimension of the first part in the direction of the first axis. In addition, the "center" of the first part means the center (center of gravity) of the closed figure defined by the contour line of the first part. In the above description, the focus is on the first part, but the same applies to the second to fourth parts.

[0157] In a specific example of method A1 (method A2), the first outer dimension is smaller than the third outer dimension, and the second outer dimension is smaller than the fourth outer dimension. According to the above method, the effect of suppressing the reduction of the detection accuracy caused by the error of the position of the first coil and the second coil in the direction of the first axis is particularly significant.

[0158] In a specific example of aspect A1 or aspect A2, the first outer dimension and the second outer dimension are equal, and the third outer dimension and the fourth outer dimension are equal. According to the above aspect, the planar shapes of the first coil and the second coil are simplified.

[0159] In a specific example (method A4) of any one of methods A1 to A3, the center of the first part and the center of the third part are located within the range of overlap between the first part and the third part when viewed from above, and the center of the second part and the center of the fourth part are located within the range of overlap between the second part and the fourth part when viewed from above. According to the above method, compared with a structure in which the center of one or both of the first part and the third part is located outside the overlapping range of the first part and the third part, it is easy for the first part to generate an induced current based on the magnetic field generated in the third part. Similarly, compared with a structure in which the center of one or both of the second part and the fourth part is located outside the overlapping range of the second part and the fourth part, it is easy for the second part to generate an induced current based on the magnetic field generated in the fourth part. Therefore, a detection signal that reflects the distance between the first coil and the second coil with high accuracy can be generated.

[0160] In addition, the "range" where the first and third parts overlap includes not only the area inside the range but also the line of the periphery (contour line) of the range. Therefore, the condition that the center of the first part or the center of the third part is located on the line of the range where the first and third parts overlap also satisfies the "range" requirement. The same is true for the range where the second and fourth parts overlap.

[0161] In a specific example (method A5) of any one of methods A1 to A4, a portion of the first portion located on the side opposite to the second portion is located outside the third portion when viewed from above, and a portion of the second portion located on the side opposite to the first portion is located outside the fourth portion when viewed from above. In the above method, compared with a method in which the entire first portion is located inside the third portion when viewed from above, or a method in which the entire second portion is located inside the fourth portion when viewed from above, it is possible to suppress a reduction in the detection accuracy of the error in the positions of the first coil and the second coil in the direction of the first axis.

[0162] In addition, in the above manner, compared with a structure in which the entire first portion is located inside the third portion when viewed from above and a structure in which the entire second portion is located inside the fourth portion when viewed from above, it is easier to ensure the area of ​​the first portion and the second portion. Therefore, a detection signal that reflects the distance between the first coil and the second coil with high accuracy can be generated.

[0163] In a specific example (method A6) of any one of the methods A1 to A5, the size of the second coil in the direction of the second axis orthogonal to the first axis exceeds the size of the first coil in the direction of the second axis. In the above method, even if an error (lateral offset) occurs in the positions of the first coil and the second coil in the direction of the second axis, the error in the output characteristics of the detection signal caused by the error can be suppressed. That is, the reduction in detection accuracy caused by the error in the positions of the first coil and the second coil in the direction of the second axis can be suppressed.

[0164] In a specific example (method A7) of any one of methods A1 to A6, the first distance is less than 2 times the second distance. In the above method, the first distance is less than 2 times the second distance, so it is possible to effectively suppress the reduction in detection accuracy caused by the error in the position of the first coil and the second coil in the direction of the second axis. In a more suitable method, the first distance is more than 1.4 times and less than 1.6 times the second distance.

[0165] In a specific example (method A8) of any one of methods A1 to A7, the first outer dimension is more than 0.5 times the third outer dimension, and the second outer dimension is more than 0.5 times the fourth outer dimension. In the above method, the area of ​​the first part and the second part is fully ensured. Therefore, a detection signal that reflects the distance between the first coil and the second coil with high accuracy can be generated.

[0166] In a specific example (method A9) of any one of the methods A1 to A8, a center-to-center distance ratio (La-Lb) / Db, which is a value obtained by dividing a distance La between the center of the first portion and the center of the second portion and a distance Lb between the center of the third portion and the center of the fourth portion by an outer dimension Db of the third portion or the fourth portion in the direction of the first axis, is greater than or equal to 0 and less than or equal to 1. In a specific example (method A10) of method A9, the center-to-center distance ratio (La-Lb) / Db is greater than or equal to 0.3 and less than or equal to 0.85.

[0167] In a specific example (method A11) of any one of methods A1 to A10, the first coil is provided on a movable member that is displaced according to a playing operation. In a more specific method (method A12), the movable member is a hammer mechanism that rotates according to the playing operation. In a structure in which the angle between the first coil and the second coil changes during the displacement of the first coil, an error is easily apparent in the output characteristics caused by the error in the positions of the first coil and the second coil. In consideration of the above tendency, the present disclosure is particularly suitable for a structure in which the first coil is provided on a hammer mechanism that rotates according to a playing operation, that is, a structure in which a detection system is utilized in detecting the position of the hammer mechanism.

[0168] A musical instrument involved in one mode (mode A13) of the present disclosure is a musical instrument having a movable member that is displaced according to a playing operation and a detection system, the detection system comprising: a first coil, which is arranged on the movable member; and a second coil, which generates a magnetic field by supplying a driving signal, and generates a detection signal corresponding to the distance between the first coil and the second coil, the first coil includes a first part and a second part arranged along a first axis, the second coil includes a third part opposite to the first part and a fourth part opposite to the second part, a first outer dimension of the first part in the direction of the first axis is less than a third outer dimension of the third part in the direction of the first axis, a second outer dimension of the second part in the direction of the first axis is less than a fourth outer dimension of the fourth part in the direction of the first axis, a first distance between the center of the first part and the center of the second part exceeds a second distance between the center of the third part and the center of the fourth part, and the center of the third part and the center of the fourth part are located between the center of the first part and the center of the second part in the direction of the first axis.

[0169] In a specific example of method A13 (method A14), the value obtained by dividing the difference (La-Lb) between the distance La between the center of the first part and the center of the second part and the distance Lb between the center of the third part and the center of the fourth part by the outer dimension Db of the third part or the fourth part in the direction of the first axis, that is, the center-to-center distance ratio (La-Lb) / Db is greater than 0 and less than 1.

[0170] [Method B]

[0171] A detection system according to one embodiment (embodiment B1) of the present disclosure is a detection system that includes a first coil that can be displaced and a second coil that generates a magnetic field by supplying a drive signal, and generates a detection signal corresponding to the distance between the first coil and the second coil, wherein the first coil includes a first portion and a second portion arranged along a first axis, and the second coil includes a third portion that is opposite to the first portion and a fourth portion that is opposite to the second portion, and a center-to-center distance ratio (La-Lb) / Db, which is a value obtained by dividing a distance La between the center of the first portion and the center of the second portion and a distance Lb between the center of the third portion and the center of the fourth portion by an outer dimension Db of the third portion or the fourth portion in the direction of the first axis, is greater than 0 and less than 1. In a specific example (embodiment B2) of embodiment B1, the center-to-center distance ratio (La-Lb) / Db exceeds 0 and is less than 1.

[0172] According to the above method, even when an error (longitudinal offset) occurs in the positions of the first coil and the second coil in the direction of the first axis, an error in the output characteristics of the detection signal (for example, the relationship between the distance between the first coil and the second coil and the signal level of the detection signal) caused by the error is suppressed. That is, it is possible to suppress a decrease in the detection accuracy caused by the error in the positions of the first coil and the second coil in the direction of the first axis.

[0173] In a specific example of method B1 (method B3), the center-to-center distance ratio (La-Lb) / Db is greater than 0.3 and less than 0.85. In a more specific method, the center-to-center distance ratio (La-Lb) / Db exceeds 0.3 and is less than 0.85. According to the above method, even if an error (longitudinal offset) occurs in the positions of the first coil and the second coil in the direction of the first axis, an error in the output characteristics of the detection signal (for example, the relationship between the distance between the first coil and the second coil and the signal level of the detection signal) caused by the error is suppressed. That is, the reduction in detection accuracy caused by the error in the positions of the first coil and the second coil in the direction of the first axis can be fully suppressed.

[0174] In a specific example (method B5) of any one of methods B1 to B4, the first coil is arranged on a hammer mechanism that rotates according to a playing operation. In a structure in which the angle between the first coil and the second coil changes during the displacement of the first coil, an error is easily apparent in the output characteristics caused by the error in the positions of the first coil and the second coil. Considering the above tendency, the present disclosure is particularly suitable for a structure in which the first coil is arranged on a hammer mechanism that rotates according to a playing operation, that is, a structure in which a detection system is used in detecting the position of the hammer mechanism.

[0175] A musical instrument according to one embodiment (embodiment B6) of the present disclosure is a musical instrument having a movable member that is displaced according to a playing operation and a detection system, the detection system comprising: a first coil provided on the movable member; and a second coil that generates a magnetic field by supplying a driving signal, the detection system generating a detection signal corresponding to the distance between the first coil and the second coil, the first coil including a first portion and a second portion arranged along a first axis, the second coil including a third portion opposite to the first portion and a fourth portion opposite to the second portion, a first outer dimension of the first portion in the direction of the first axis being less than or equal to a third outer dimension of the third portion in the direction of the first axis, a second outer dimension of the second portion in the direction of the first axis being less than or equal to a fourth outer dimension of the fourth portion in the direction of the first axis, and a center-to-center distance ratio (La-Lb) / Db, which is a value obtained by dividing a distance La between a center of the first portion and a center of the second portion and a distance Lb between a center of the third portion and a center of the fourth portion by an outer dimension Db of the third portion or the fourth portion in the direction of the first axis, being greater than or equal to 0 and less than or equal to 1.

Claims

1. A detection system comprising: a first coil capable of displacement; and The second coil generates a magnetic field by supplying a driving signal. The detection system generates a detection signal corresponding to the distance between the first coil and the second coil, The first coil includes a first portion and a second portion arranged along a first axis, The second coil includes a third portion opposite to the first portion and a fourth portion opposite to the second portion, A first outer dimension of the first portion in the direction of the first axis is less than or equal to a third outer dimension of the third portion in the direction of the first axis. A second outer dimension of the second portion in the direction of the first axis is less than or equal to a fourth outer dimension of the fourth portion in the direction of the first axis. a first distance between the center of the first portion and the center of the second portion exceeds a second distance between the center of the third portion and the center of the fourth portion, The center of the third portion and the center of the fourth portion are located between the center of the first portion and the center of the second portion in the direction of the first axis.

2. The detection system according to claim 1, wherein: The first outer dimension is lower than the third outer dimension, The second outer dimension is lower than the fourth outer dimension.

3. The detection system according to claim 2, wherein: The first outer dimension and the second outer dimension are equal, The third outer dimension and the fourth outer dimension are equal.

4. The detection system according to claim 1, wherein: The center of the first portion and the center of the third portion are located within the overlapping range of the first portion and the third portion when viewed from above. The center of the second portion and the center of the fourth portion are located within a range where the second portion and the fourth portion overlap when viewed from above.

5. The detection system according to claim 1, wherein: A portion of the first portion located on the opposite side to the second portion is located outside the third portion in a plan view, A portion of the second portion located on the opposite side to the first portion is located outside the fourth portion in a plan view.

6. The detection system according to claim 1, wherein: A size of the second coil in a direction of a second axis orthogonal to the first axis exceeds a size of the first coil in the direction of the second axis.

7. The detection system according to claim 1, wherein: The first distance is less than or equal to twice the second distance.

8. The detection system according to claim 1, wherein: The first outer dimension is more than 0.5 times the third outer dimension, The second outer dimension is greater than 0.5 times the fourth outer dimension.

9. The detection system according to claim 1, wherein: The value obtained by dividing the difference (La-Lb) between the distance La between the center of the first part and the center of the second part, and the distance Lb between the center of the third part and the center of the fourth part by the outer dimension Db of the third part or the fourth part in the direction of the first axis, i.e., the center distance ratio (La-Lb) / Db, is greater than 0 and less than 1.

10. The detection system according to claim 9, wherein: The center-to-center distance ratio (La-Lb) / Db is greater than or equal to 0.3 and less than or equal to 0.

85.

11. The detection system according to claim 1, wherein: The first coil is provided on a movable member that is displaced according to a performance operation.

12. The detection system according to claim 11, wherein: The movable member is a hammer mechanism that rotates according to the playing operation.

13. A musical instrument having: a movable member that is displaced according to a performance operation; and Detection system, The detection system has: A first coil is disposed on the movable member; and The second coil generates a magnetic field by supplying a driving signal. The detection system generates a detection signal corresponding to the distance between the first coil and the second coil, The first coil includes a first portion and a second portion arranged along a first axis, The second coil includes a third portion opposite to the first portion and a fourth portion opposite to the second portion, A first outer dimension of the first portion in the direction of the first axis is less than or equal to a third outer dimension of the third portion in the direction of the first axis. A second outer dimension of the second portion in the direction of the first axis is less than or equal to a fourth outer dimension of the fourth portion in the direction of the first axis. a first distance between the center of the first portion and the center of the second portion exceeds a second distance between the center of the third portion and the center of the fourth portion, The center of the third portion and the center of the fourth portion are located between the center of the first portion and the center of the second portion in the direction of the first axis.

14. The musical instrument of claim 13, wherein: The value obtained by dividing the difference (La-Lb) between the distance La between the center of the first part and the center of the second part, and the distance Lb between the center of the third part and the center of the fourth part by the outer dimension Db of the third part or the fourth part in the direction of the first axis, i.e., the center distance ratio (La-Lb) / Db, is greater than 0 and less than 1.

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