Detection system and musical instrument

Abstract

To suppress deterioration of detection accuracy due to an error of positions of coils in a detection system for generating a detection signal corresponding to a distance between a displaceable coil and a coil generating a magnetic field.SOLUTION: In a keyboard unit, a movable coil 60 arranged in a drive mechanism having a hammer includes a first portion 61 and a second portion 62. A detection coil 70 includes a third portion 73 facing the first portion 61 and a fourth portion 74 facing the second portion 62. An external dimension Da1 of the first portion in a Y-axis direction is less than or equal to an external dimension Db3 of the third portion in the Y-axis direction, and an external dimension Da2 of the second portion in the Y-axis direction is less than or equal to an external dimension Db4 of the fourth portion in the Y-axis direction. A distance La between a center O1 of the first portion and a center O2 of the second portion exceeds a distance Lb between a center O3 of the third portion and a center O4 of the fourth portion. The center O3 of the third portion and the center O4 of the fourth portion are positioned between the center O1 of the first portion and the center O2 of the second portion.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present disclosure relates to a technology for detecting displacement by utilizing magnetism. [Background technology]

[0002] For example, various techniques have been proposed for detecting the displacement of movable parts such as keys or hammer shanks in keyboard instruments. For example, Patent Document 1 discloses a keyboard instrument that generates a detection signal according to the distance between a first coil installed on a performance operator and a second coil that generates a magnetic field. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2021 / 100448 Summary of the Invention [Problem to be solved by the invention]

[0004] An error may occur in the position of each of the first coil and the second coil. When an error occurs in the position of the first coil and the second coil, the error may cause a decrease in detection accuracy. In consideration of the above circumstances, one aspect of the present disclosure aims to suppress a decrease in detection accuracy caused by an error in the position of the first coil and the second coil in a configuration that generates a detection signal according to the distance between a displaceable first coil and a second coil that generates a magnetic field by supplying a drive signal. [Means for solving the problem]

[0005] In order to solve the above problems, a detection system according to one embodiment of the present disclosure comprises a displaceable first coil and a second coil that generates a magnetic field when a drive signal is supplied, and generates a detection signal according 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, the second coil includes a third portion facing the first portion and a fourth portion facing the second portion, a first outer dimension of the first portion in the direction of the first axis is equal to or smaller 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 is equal to or smaller 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 exceeds a second distance between the center of the third portion and the center of the fourth portion, and 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.

[0006] According to one embodiment of the present disclosure, there is provided a musical instrument comprising a movable member that is displaced in response to a playing operation, and a detection system, the detection system comprising a first coil disposed on the movable member, and a second coil that generates a magnetic field in response to a supply of a drive signal, and generates a detection signal in accordance with 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 facing the first portion and a fourth portion facing the second portion, and the detection signal is generated according to ... A first outer dimension of the first part in the direction of the first axis is less than or equal to 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 or equal to a fourth outer dimension of the fourth part in the direction of the first axis, a first distance between a center of the first part and a center of the second part is greater than 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. [Brief description of the drawings]

[0007] [Figure 1] 1 is a block diagram illustrating a configuration of a keyboard instrument according to a first embodiment. [Diagram 2] FIG. 2 is a side view illustrating the configuration of a keyboard unit. [Diagram 3] FIG. 2 is a block diagram illustrating a configuration of a detection system and a control system. [Figure 4] FIG. 2 is a circuit diagram of a magnetic sensor. [Diagram 5] FIG. 2 is a block diagram illustrating a configuration of a drive circuit. [Figure 6] FIG. [Figure 7] 7 is a cross-sectional view taken along line VII-VII in FIG. 6. [Figure 8] FIG. 2 is a plan view of a signal generating unit. [Figure 9] 9 is a cross-sectional view taken along line IX-IX in FIG. 8. [Figure 10] 4 is a schematic diagram showing the dimensional and positional relationship between a moving coil and a detection coil. FIG. [Figure 11] FIG. 4 is an explanatory diagram of the effect of the first embodiment. [Figure 12] 10 is a graph showing the relationship between the center distance ratio and the speed fluctuation amount in the second embodiment. [Figure 13] FIG. 13 is a schematic diagram of a modified keyboard instrument. [Figure 14] FIG. 13 is a schematic diagram of a pedal mechanism in a modified example. [Figure 15] 13A and 13B are schematic diagrams showing the dimensional and positional relationship between a moving coil and a detection coil in a modified example. [Figure 16] 13A and 13B are schematic diagrams showing the dimensional and positional relationship between a moving coil and a detection coil in a modified example. [Figure 17] 13A and 13B are schematic diagrams showing the dimensional and positional relationship between a moving coil and a detection coil in a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] A: First embodiment 1 is a block diagram illustrating a configuration of a keyboard instrument 100 according to a first embodiment of the present disclosure. The keyboard instrument 100 is an electronic instrument (specifically, an electronic piano) including a keyboard unit 10, a detection system 30, a control system 40, and a sound emission system 50.

[0009] The keyboard unit 10 includes a keyboard 12. The keyboard 12 is made up of a number of keys 14 (white keys and black keys) corresponding to different pitches. The keys 14 are arranged along the X-axis. The X-axis is an axis extending laterally of the user in a horizontal plane. Each key 14 is displaced in response to an operation by the user for playing (hereinafter referred to as a "playing operation"). The playing operation by the user includes, for example, pressing and releasing a key. The detection system 30 detects the playing operation by the user.

[0010] The control system 40 generates an audio signal V according to the result of detection by the detection system 30. The audio signal V is a signal representing a waveform of a musical sound according to a performance operation. The control system 40 may be configured separately from the keyboard instrument 100. For example, a general-purpose information processing device such as a smartphone, a tablet terminal, or a personal computer may be used as the control system 40.

[0011] The sound emission system 50 emits musical tones represented by the acoustic signal V. For example, one or more speakers, or headphones (earphones) worn on the user's head are used as the sound emission system 50. Note that the sound emission system 50 configured separately from the keyboard instrument 100 may be connected to the keyboard instrument 100 by wire or wirelessly.

[0012] Fig. 2 is a side view illustrating a specific configuration of the keyboard unit 10. Fig. 2 illustrates a configuration focusing on one arbitrary key 14 of the keyboard 12. Each key 14 of the keyboard 12 is supported by a support structure 18 with a balance pin 16 as a fulcrum. The support structure 18 is a structure (frame) that supports each element of the keyboard instrument 100. The tip of the key 14 is displaced vertically in response to the performance operation by the user.

[0013] The keyboard unit 10 includes, in addition to the keyboard 12, a plurality of drive mechanisms 20 corresponding to the different keys 14. Each drive mechanism 20 is an action mechanism that operates in response to a performance operation by a user. The drive mechanism 20 includes a transmission mechanism 21 and a hammer mechanism 22.

[0014] The transmission mechanism 21 is a mechanism that transmits the displacement of each key 14 in response to a playing operation to the hammer mechanism 22. More specifically, the transmission mechanism 21 is made up of mechanical elements such as a wippen or a jack.

[0015] The hammer mechanism 22 includes a hammer shank 221, a weight portion 222, and a holding member 223. The hammer shank 221 is a long, cylindrical structure. The weight portion 222 is a metal counterweight that allows the user to perceive an appropriate sense of weight when performing. The holding member 223 is a structure fixed to the hammer shank 221. The transmission mechanism 21 rotates the hammer mechanism 22 in conjunction with the displacement of the key 14. In other words, the hammer mechanism 22 is a movable member that can be displaced in response to the user's performance operation.

[0016] 3 is a block diagram illustrating the configuration 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 that drives each of the plurality of magnetic sensors 31. The magnetic sensor 31 corresponding to each drive mechanism 20 is a sensor that detects 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 pair of the detected portion 32 and the signal generating portion 33 is provided for each hammer mechanism 22.

[0017] 4 is a circuit diagram illustrating an electrical configuration of any one of the magnetic sensors 31. The detected part 32 is a resonant circuit including a capacitive element 321 and a moving coil 60. One end of the moving coil 60 and one end of the capacitive element 321 are connected to each other, and the other end of the moving coil 60 and the other end of the capacitive element 321 are connected to each other. The moving coil 60 is an example of a "first coil."

[0018] The signal generating unit 33 is a resonant circuit including an input terminal 331, an output terminal 332, a resistive element 333, a detection coil 70, a capacitive element 334, and a capacitive element 335. One end of the resistive element 333 is connected to the input terminal 331, and the other end of the resistive element 333 is connected to one end of the capacitive element 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 capacitive element 335. The other end of the capacitive element 334 and the other end of the capacitive element 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 be equal to each other. However, the resonant frequency of the signal generating unit 33 and the resonant frequency of the detected unit 32 may be different. The detection coil 70 is an example of a "second coil".

[0019] 2, each of the multiple detected parts 32 is mounted on a movable substrate 37. The movable substrate 37 is a wiring substrate individually installed for each key 14. Therefore, the multiple detected parts 32 are arranged in the direction of the X-axis. The movable substrate 37 is supported by the aforementioned holding member 223. In other words, the detected parts 32 (movable coil 60) are mounted on the hammer mechanism 22. Therefore, the movable coil 60 is displaced in response to the playing operation by the user.

[0020] On the other hand, the multiple signal generating units 33 are mounted on a fixed substrate 38. The fixed substrate 38 is a wiring board that extends in the X-axis direction across the multiple keys 14. The multiple signal generating units 33 are arranged in the X-axis direction. The fixed substrate 38 is fixed to the support structure 18. Therefore, while the moving coils 60 are displaced in conjunction with playing operations, the detection coils 70 are not displaced when playing operations occur.

[0021] The moving coil 60 and the detection coil 70 face each other with a gap between them. As described above, the moving coil 60 is mounted on the rotatable hammer mechanism 22, and the detection coil 70 is fixed to the support structure 18. Therefore, the distance between the moving coil 60 and the detection coil 70 varies in conjunction with the performance operation by the user. The drive circuit 35 in FIG. 4 generates a detection signal D according to the distance between the moving coil 60 and the detection coil 70.

[0022] FIG. 5 is a block diagram illustrating a specific configuration of the drive circuit 35. The drive circuit 35 includes a supply circuit 351 and an output circuit 352. The supply circuit 351 supplies a drive signal S to the input terminal 331 of each of the multiple signal generating units 33. For example, the supply circuit 351 is a demultiplexer that supplies the drive signal S to each of the multiple signal generating units 33 in a time-division manner. The drive signal S is a signal whose level periodically varies. For example, a periodic signal of an arbitrary waveform such as a sine wave or a rectangular wave is used as the drive signal S. The frequency of the drive signal S is sufficiently shorter than the time length of the period during which the drive signal S is supplied to one signal generating unit 33. In addition, the frequency of the drive signal S is set to a frequency approximately equal to the resonance frequency of the signal generating unit 33 and the detected unit 32.

[0023] The drive signal S is supplied to the detection coil 70 via the input terminal 331 and the resistive 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 moving coil 60 of the detected part 32 by electromagnetic induction caused by the magnetic field generated in the detection coil 70. That is, a magnetic field is generated in the moving coil 60 in a direction that offsets the change in the magnetic field of the detection coil 70. The magnetic field generated in the moving coil 60 changes depending on the distance between the moving coil 60 and the detection coil 70. Therefore, a detection signal d whose amplitude varies depending on the distance between the moving coil 60 and the detection coil 70 is output from the output terminal 332 of the signal generating unit 33. The detection signal d is a periodic signal whose level varies at the same frequency as the drive signal S.

[0024] 5 is a multiplexer that generates a detection signal D by arranging on a time axis the detection signals d sequentially output from each of the multiple signal generating units 33. That is, the detection signal D is a periodic signal whose amplitude varies according to the distance between the moving coil 60 and the detection coil 70. As described above, since the distance between the moving coil 60 and the detection coil 70 depends on the position of the hammer mechanism 22, the detection signal D is expressed as a signal according to the position of each of the multiple hammer mechanisms 22.

[0025] As described above, the detection system 30 of the first embodiment generates a detection signal D according to the distance between the moving coil 60 and the detection coil 70. The detection signal D generated by the detection system 30 is supplied to the control system 40. Note that the detection signal D that has been rectified (half-wave rectification or full-wave rectification) and smoothed after generation by the output circuit 352 may be supplied to the control system 40.

[0026] 3 generates an acoustic signal V in response to the detection signal D. The control system 40 is realized by a computer system including a control device 41, a storage device 42, an A / D converter 43, and a sound source device 44. The control system 40 may be realized by a single device, or may be realized by a plurality of devices configured separately from each other.

[0027] The control device 41 is composed of one or more processors that control each element of the keyboard instrument 100. Specifically, the control device 41 is composed of one or more types of 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).

[0028] The storage device 42 is one or more memories that store the programs executed by the control device 41 and the data used by the control device 41. The storage device 42 is configured with a known recording medium, such as a magnetic recording medium or a semiconductor recording medium. The storage device 42 may be configured with a combination of multiple types of recording media. Also, the storage device 42 may be a portable recording medium that is detachable from the keyboard instrument 100, or an external recording medium (e.g., online storage) with which the keyboard instrument 100 can communicate.

[0029] 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 conversion by the A / D converter 43 to analyze the position of each of the multiple hammer mechanisms 22.

[0030] The sound source device 44 generates an audio signal V representing the sound instructed by the control device 41. The control device 41 instructs the sound source device 44 to generate musical tones according to the detection signal D. For example, the sound source device 44 is instructed to generate musical tones with acoustic characteristics (e.g., sound quality or volume) according to the detection signal D. Thus, an audio signal V representing musical tones according to the performance operation by the user is generated. Note that the control device 41 may realize the functions of the sound source device 44 by executing a program stored in the storage device 42.

[0031] FIG. 6 is a plan view of the detected part 32. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6. FIG. 6 and FIG. 7 show three mutually orthogonal axes (X-axis, Y-axis, and Z-axis). As described above, the X-axis is an axis along the arrangement of the multiple keys 14 (i.e., the horizontal direction). The Y-axis is an axis along the longitudinal direction of the hammer mechanism 22. The Z-axis is an axis perpendicular to the XY plane. The Y-axis is an example of the "first axis," and the X-axis is an example of the "second axis." Observing an object with a line of sight along the Z-axis is hereinafter referred to as "planar view."

[0032] As described above, the detected part 32 is mounted on the movable substrate 37. The movable substrate 37 is a hard wiring substrate made of an insulating material. The movable substrate 37 includes a first face F1 and a second face F2. The first face F1 and the second face F2 are surfaces opposite to each other. The first face F1 is a surface of the movable substrate 37 facing the signal generating part 33, and the second face F2 is a surface of the movable substrate 37 closer to the hammer mechanism 22. A capacitive element 321 is mounted on the first face F1.

[0033] 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 patterns 371 and 372 are formed by patterning a conductive film that covers the movable substrate 37, for example.

[0034] 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 in the direction of the Y axis (i.e., the longitudinal direction of each key 14). Specifically, the first portion 61 is located in the positive direction of the Y axis when viewed from the second portion 62.

[0035] The first portion 61 is formed by laminating the winding portion 611 and the winding portion 612. The second portion 62 is formed by laminating the winding portion 621 and the winding portion 622. The winding portion 611 and the winding portion 621 are included in the conductive pattern 371 on the first face F1, and are formed in a spiral shape that rotates clockwise from the inside to the outside in a plan view. On the other hand, the winding portion 612 and the winding portion 622 are included in the conductive pattern 372 on the second face F2, and are formed in a spiral shape that rotates counterclockwise from the inside to the outside in a plan view. The capacitance element 321 is provided between the winding portion 611 and the winding portion 621, and the winding portion 612 and the winding portion 622 are mutually connected on the second face F2.

[0036] The center of winding portion 611 and the center of winding portion 612 are electrically connected to each other via conductive hole H1. Similarly, the center of winding portion 621 and the center of winding portion 622 are electrically connected to each other via conductive hole H2. Conduction holes H1 and H2 are through holes formed in movable substrate 37.

[0037] 6, in a state where a current flows in the first direction α1 through the winding portion 611, a current also flows in the first direction α1 through the winding portion 612. In addition, in a state where a current flows in the first direction α1 through the winding portion 611, a current flows in the second direction α2 opposite to the first direction α1 through the winding portion 621 and the winding portion 622. That is, when an induced current is generated in the movable coil 60 due to electromagnetic induction of the magnetic field generated in the detection coil 70, magnetic fields in mutually opposite directions are generated in the first portion 61 and the second portion 62, as illustrated in FIG.

[0038] Fig. 8 is a plan view of the signal generating unit 33. Fig. 9 is a cross-sectional view taken along line IX-IX in Fig. 8. Figs. 8 and 9 show three axes (X-axis, Y-axis, and Z-axis) corresponding to Figs. 6 and 7. Note that the angle between the movable substrate 37 and the fixed substrate 38 varies with the rotation of the hammer mechanism 22, but in the following description, it is assumed for the sake of convenience that the movable substrate 37 and the fixed substrate 38 are substantially parallel to each other, and the three axes are shared between the movable substrate 37 and the fixed substrate 38.

[0039] As described above, the signal generating unit 33 is disposed 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 opposite each other. The third surface F3 is the surface of the fixed substrate 38 that faces the movable substrate 37. A resistive element 333, a capacitive element 334, and a capacitive element 335 are mounted on the third surface F3 for each signal generating unit 33.

[0040] 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 multiple signal generating units 33. On the other hand, a conductive pattern 382 is formed on the fourth surface F4. The conductive patterns 381 and 382 are formed by, for example, patterning a conductive film that covers the fixed substrate 38.

[0041] 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 Y-axis direction (i.e., the longitudinal direction of each key 14). Specifically, the third portion 73 is located in the positive direction of the Y-axis when viewed from the fourth portion 74. The third portion 73 of the detection coil 70 faces the first portion 61 of the moving coil 60 corresponding to the detection coil 70. That is, when viewed from the Z-axis direction, the first portion 61 and the third portion 73 overlap each other. The fourth portion 74 of the detection coil 70 faces the second portion 62 of the moving coil 60 corresponding to the detection coil 70. That is, the second portion 62 and the fourth portion 74 overlap each other when viewed from the Z-axis direction.

[0042] The third portion 73 is formed by laminating the winding portion 731 and the winding portion 732. The fourth portion 74 is formed by laminating 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 face F3, and are formed in a spiral shape that rotates 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 face F4, and are formed in a spiral shape that rotates counterclockwise from the inside to the outside in a plan view.

[0043] The center of winding portion 731 and the center of winding portion 732 are electrically connected to each other via conductive hole H3. Similarly, the center of winding portion 741 and the center of winding portion 742 are electrically connected to each other via conductive hole H4. Conduction holes H3 and H4 are through holes formed in fixed substrate 38.

[0044] Winding portion 731 is connected to input terminal 331 via resistive element 333, and winding portion 741 is connected to output terminal 332. In addition, capacitive element 334 is provided between resistive element 333 and ground terminal 336, and capacitive element 335 is provided between output terminal 332 and ground terminal 336.

[0045] The signal generating unit 33 includes a connecting wire 76 in the conductive pattern 381. The winding portion 732 of the third portion 73 is electrically connected to one end of the connecting wire 76 through a conductive hole Ha, and the winding portion 742 of the fourth portion 74 is electrically connected to the other end of the connecting wire 76 through a conductive hole Hb. That is, the winding portion 732 and the winding portion 742 are electrically connected to each other through the connecting wire 76.

[0046] As can be seen from Fig. 8, when a current flows in the first direction α1 through the winding portion 731, a current also flows in the first direction α1 through the winding portion 732. When a current flows in the first direction α1 through the winding portion 731, a current flows in the second direction α2 opposite to the first direction α1 through the winding portion 741 and the winding portion 742. That is, when a driving signal S is supplied to the detection coil 70, magnetic fields in mutually opposite directions are generated in the third portion 73 and the fourth portion 74, as illustrated in Fig. 9. Note that the driving signal S is a signal whose signal level is periodically inverted, so that the first direction α1 and the second direction α2 are periodically inverted while maintaining a mutually opposite relationship.

[0047] FIG. 10 is a schematic diagram showing the relationship in size and position between the moving coil 60 and the detection coil 70. In FIG. 10, the outer shapes of the first portion 61 and the second portion 62 of the moving coil 60 and the outer shapes of the third portion 73 and the fourth portion 74 of the detection coil 70 are shown together. Note that in FIG. 10, the third portion 73 and the fourth portion 74 are shown adjacent to each other for convenience, but in reality, as shown in FIG. 8, the third portion 73 and the fourth portion 74 are adjacent to each other with a gap therebetween. However, the third portion 73 and the fourth portion 74 may be adjacent to each other without a gap therebetween as shown in FIG. 10.

[0048] As illustrated in FIG. 10, when the movable substrate 37 and the fixed substrate 38 are substantially parallel to each other, the first portion 61 and the third portion 73 overlap each other in a planar view, and the second portion 62 and the fourth portion 74 overlap each other in a planar view.

[0049] The outer dimension Da1 in FIG. 10 is the dimension of the first portion 61 in the direction of the Y axis. Similarly, the outer dimension Da2 in FIG. 10 is the dimension of the second portion 62 in the direction of the Y axis. The outer dimension Da1 of the first portion 61 means the dimension (size) of a closed figure defined by the contour of the first portion 61 in the direction of the Y axis, and can also be said as the maximum dimension of the first portion 61 in the direction of the Y axis. The contour (closed figure) of the first portion 61 is the outermost periphery of the winding portion 611 or the winding portion 612. Although the first portion 61 has been focused on above, the outer dimension Da2 of the second portion 62 is defined in the same manner.

[0050] 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 may be expressed as the outer dimension Da (Da=Da1=Da2). Note that 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."

[0051] The outer dimension Db3 in FIG. 10 is the dimension of the third portion 73 in the direction of the Y axis. Similarly, the outer dimension Db4 in FIG. 10 is the dimension of the fourth portion 74 in the direction of the Y axis. The outer dimension Db3 of the third portion 73 means the dimension (size) of the closed figure defined by the contour of the third portion 73 in the direction of the Y axis when focusing on the closed figure, and can also be said as the maximum dimension of the third portion 73 in the direction of the Y axis. The contour (closed figure) of the third portion 73 is the outermost periphery of the winding portion 731 or the winding portion 732. Although the third portion 73 has been focused on above, the outer dimension Db4 of the fourth portion 74 is defined in the same manner.

[0052] In the first embodiment, the outer dimension Db3 of the third portion 73 and the outer dimension Db4 of the fourth portion 74 are equal. Therefore, in the following description, the outer dimension Db3 and the outer dimension Db4 may be expressed as the outer dimension Db (Db = Db3 = Db4). Note that 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".

[0053] The outer dimension Da1 of the first part 61 is equal to or less than the outer dimension Db3 of the third part 73 (Da1 ≤ Db3). In the first embodiment, the outer dimension Da1 is less than the outer dimension Db3 (Da1 < Db3). Also, the outer dimension Da1 is equal to or more than 0.5 times the outer dimension Db3 (0.5Db3 ≤ Da1 ≤ Db3).

[0054] Similarly, the outer dimension Da2 of the second part 62 is equal to or less than the outer dimension Db4 of the fourth part 74 (Da2 ≤ Db4). In the first embodiment, the outer dimension Da2 is less than the outer dimension Db4 (Da2 < Db4). Also, the outer dimension Da2 is equal to or more than 0.5 times the outer dimension Db4 (0.5Db4 ≤ Da2 ≤ Db4).

[0055] As described above, in the first embodiment, the outer dimension Da1 and the outer dimension Da2 are equal, and the outer dimension Db3 and the outer dimension Db4 are equal. Therefore, the outer dimension Da of each of the first part 61 and the second part 62 is equal to or less than the outer dimension Db of each of the third part 73 and the fourth part 74 (Da ≤ Db). Specifically, the outer dimension Da is less than the outer dimension Db (Da < Db). The outer dimension Da in the first embodiment is equal to or more than 0.5 times the outer dimension Db (0.5Db ≤ Da ≤ Db). Note that the outer dimension Da and the outer dimension Db may be equal numerical values.

[0056] The center - to - center distance La in FIG. 10 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. The center O1 of the first part 61 means the center (centroid) of the closed figure defined by the contour line of the first part 61. In the first embodiment, the through - hole H1 corresponds to the center O1. Similarly, the through - hole H2 of the second part 62 corresponds to the center O2. The center - to - center distance La is an example of the "first distance".

[0057] The center-to-center distance Lb in FIG. 10 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 (centroid) of a closed figure defined by the contour line of the third portion 73. In the first embodiment, the through hole H3 corresponds to the center O3. Similarly, the through hole H4 of the fourth portion 74 corresponds to the center O4. The center-to-center distance Lb is an example of a "second distance."

[0058] In the first embodiment, the center-to-center distance La between the first portion 61 and the second portion 62 is greater than the center-to-center distance Lb between the third portion 73 and the fourth portion 74 (La>Lb). In addition, the center-to-center distance La is equal to or less than twice the center-to-center distance Lb (Lb <La≦2Lb)。

[0059] 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 centers O1 and O4, and the center O4 is located between the centers O2 and O3.

[0060] 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 illustrates an edge S1 of the first portion 61 located in the negative direction of the Y axis, and an edge S3 of the third portion 73 located in the positive direction of the Y axis. The range B13 is a range between the edge S1 and the edge S3. That is, the center O1 and the center O3 are located between the edge S1 and the edge S3. Note that the case where the center O1 or the center O3 is located on the line of the edge S1 or the edge S3 also falls under "within the range B13".

[0061] 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. In other words, the center O2 and the center O4 are located between the edge S2 and the edge S4. Note that the case where the center O2 or the center O4 is located on the line of the edge S2 or the edge S4 also falls under "within the range B24."

[0062] As described above, in the first embodiment, the center-to-center distance La and the center-to-center distance Lb are set so that the centers O1 and O3 are located within the range B13, and the centers O2 and O4 are located within the range B24. According to the above configuration, it is easier to generate an induced current in the first portion 61 due to the magnetic field generated in the third portion 73, compared to a configuration in which one or both of the center O1 of the first portion 61 and the center O3 of the third portion 73 are located outside the range B13. Similarly, it is easier to generate an induced current in the second portion 62 due to the magnetic field generated in the fourth portion 74, compared to a configuration in which one or both of the center O2 of the second portion 62 and the center O4 of the fourth portion 74 are located outside the range B24. Therefore, it is possible to generate a detection signal D that reflects the distance between the moving coil 60 and the detection coil 70 with high accuracy.

[0063] Part P1 of the first part 61, which is located on the opposite side to the second part 62, is located outside the third part 73 in a planar view. That is, part P1 is a part of the first part 61 that is located in the positive direction of the Y axis from the edge S3 of the third part 73. That is, part P1 of the first part 61 protrudes in the positive direction of the Y axis from the edge S3. As described above, the first part 61 of the first embodiment partially overlaps with the third part 73 in a planar view.

[0064] Part P2 of the second part 62, which is located on the opposite side to the first part 61, is located outside the fourth part 74 in a planar view. That is, part P2 is a part of the second part 62 that is located in the negative direction of the Y axis from the edge S4 of the fourth part 74. That is, part P2 of the second part 62 protrudes in the negative direction of the Y axis from the edge S4. As described above, the second part 62 of the first embodiment partially overlaps with the fourth part 74 in a planar view.

[0065] Fig. 11 shows the results of evaluating the detection characteristics of the detection system 30 for each of a number of test samples in which the center-to-center distance La is changed. In Fig. 11, the detection error characteristics are shown for each test sample.

[0066] 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 position error between the moving coil 60 and the detection coil 70 in the direction of the Y axis. In other words, the numerical value 0 of the position error E means that the moving coil 60 is at the designed target position relative to the detection coil 70 in the direction of the Y axis. A state in which the moving coil 60 is displaced in the negative direction of the Y axis with respect to the target position is represented by a negative number of the position error E, and a state in which the moving coil 60 is displaced in the positive direction of the Y axis with respect to the target position is represented by a positive number of the position error E.

[0067] The measurement speed Q is the speed of the moving coil 60 determined by analyzing the detection signal D generated by the detection system 30 when the moving coil 60 is moved at a predetermined speed. The measurement speed Q is normalized so that the measurement speed Q is 0 when the position error E is 0.

[0068] The detection error characteristic in Fig. 11 shows a speed fluctuation amount Δ. The speed fluctuation amount Δ is the absolute value of the difference between the maximum and minimum values ​​of the measured speed Q within a range R of values ​​assumed for the position error E. In other words, the speed fluctuation amount Δ is an index that indicates how the measured speed Q determined from the detection signal D changes in response to a position error (position error E) that exists between the moving coil 60 and the detection coil 70. The range R indicates the allowable range of the position error E.

[0069] That is, when the speed fluctuation amount Δ is large, the measured speed Q fluctuates significantly even if there is a slight error in the positions of the moving coil 60 and the detection coil 70. On the other hand, when the speed fluctuation amount Δ is small, the error in the measured speed Q can be suppressed even if there is an error in the positions of the moving coil 60 and the detection coil 70. As can be understood from the above explanation, in order to suppress a decrease in detection accuracy caused by an error in the positions of the moving coil 60 and the detection coil 70, it is necessary to suppress the speed fluctuation amount Δ to a small value.

[0070] 11 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.

[0071] On the other hand, test samples #1 to #3 are samples in which the center-to-center distance La between the first portion 61 and the second portion 62 is gradually increased from the reference sample while the center-to-center distance Lb between the third portion 73 and the fourth portion 74 is kept fixed.

[0072] As illustrated in Fig. 11, the speed fluctuation amount Δ of test sample #1 to test sample #3 is less than the speed fluctuation amount Δ of the reference sample. Therefore, it can be evaluated that the speed fluctuation amount Δ is suppressed by the configuration of Fig. 10 in which the center-to-center distance La is greater than the center-to-center distance Lb. In other words, it is possible to suppress the deterioration of detection accuracy caused by the position error between the moving coil 60 and the detection coil 70 in the Y-axis direction.

[0073] Moreover, the test sample #1 has a configuration in which the first portion 61 entirely overlaps with the third portion 73, and the second portion 62 entirely overlaps with the fourth portion 74. On the other hand, the test sample #2 and the test sample #3 have a configuration 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 fluctuation amount Δ of the test sample #2 and the test sample #3 is less than the speed fluctuation amount Δ of the reference sample and the test sample #1. Therefore, it can be evaluated that the speed fluctuation amount Δ is suppressed by the configuration in which the first portion 61 includes the portion P1 and the configuration in which the second portion 62 includes the portion P2. That is, according to the first embodiment, it is possible to suppress the deterioration of the detection accuracy caused by the position error between the moving coil 60 and the detection coil 70 in the Y-axis direction.

[0074] 10, the dimension (i.e., width) Wb of the detection coil 70 in the X-axis direction is greater than the dimension Wa of the moving coil 60 in the X-axis direction (Wb>Wa). With the above configuration, even if an error (lateral shift) occurs in the positions of the moving coil 60 and the detection coil 70 in the X-axis direction, the area of ​​the overlapping portion between the moving coil 60 and the detection coil 70 does not change. Therefore, the occurrence of an error in the output characteristics of the detection signal D due to the positional error of the moving coil 60 and the detection coil 70 in the X-axis direction is suppressed. In other words, it is possible to suppress a decrease in detection accuracy due to the positional error between the moving coil 60 and the detection coil 70 in the X-axis direction.

[0075] B: Second embodiment A second embodiment of the present disclosure will be described. Note that, for elements having the same functions as those in the first embodiment in each of the following exemplary aspects, the same reference numerals as those in the first embodiment will be used, and detailed descriptions of each will be omitted as appropriate.

[0076] In the second embodiment, attention is focused on the center-to-center distance ratio C. The center-to-center distance ratio C is a dimensionless quantity expressed by the following formula (1). C=(La-Lb) / Db (1)

[0077] As can be understood from formula (1), the center-to-center distance ratio C is a numerical 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. In other words, the center-to-center distance ratio C means the ratio of the difference (La-Lb) between the center-to-center distance La and the center-to-center distance Lb to the outer dimension Db of the third portion 73 or the fourth portion 74.

[0078] 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 can also be expressed as a value ({(La-Lb) / 2} / {Db / 2}) obtained by dividing the distance (La-Lb) / 2 between the center O1 (O2) and the center O3 (O4) by half the outer dimension Db, Db / 2.

[0079] Fig. 12 shows the results of evaluating the detection characteristics of the detection system 30 for each of a plurality of test samples in which the center-to-center distance ratio C is changed. Specifically, Fig. 12 shows the relationship between the center-to-center distance ratio C (horizontal axis) and the speed fluctuation amount Δ (vertical axis) for a plurality of test samples. The plurality of test samples in the second embodiment include samples in which the dimensional and positional relationship between the moving coil 60 and the detection coil 70 satisfies the conditions exemplified in the first embodiment, as well as samples in which the conditions are not satisfied.

[0080] As can be seen from Fig. 12, there is a correlation between the center-to-center distance ratio C and the speed fluctuation amount Δ. Specifically, the speed fluctuation amount Δ decreases as the center-to-center distance ratio C increases from 0, and the speed fluctuation amount Δ increases as the center-to-center distance ratio C increases in a range exceeding a predetermined value (for example, a value near 0.6). That is, there is a general tendency that the speed fluctuation amount Δ becomes a minimum value (local minimum value) when the center-to-center distance ratio C is a value near 0.6.

[0081] Focus on the reference sample that serves as the standard for the speed variation amount Δ. The reference sample is a sample in which, similar to the first embodiment, the center O1 of the first part 61 and the center O3 of the third part 73 coincide, and the center O2 of the second part 62 and the center O4 of the fourth part 74 coincide. That is, in the reference sample, the center - to - center distance La and the center - to - center distance Lb coincide. The speed variation amount Δ of the reference sample is 9.28.

[0082] As can be understood from FIG. 12, the range of the center - to - center distance ratio C where the speed variation amount Δ is less than the numerical value of the reference sample (Δ = 9.28) is 0 or more and 1 or less. Based on the results of the above considerations, in the second embodiment, the dimensions and positions of the respective elements of the movable coil 60 and the detection coil 70 are selected so that the center - to - center distance ratio C is 0 or more and 1 or less (0 ≦ C ≦ 1). The configuration where the center - to - center distance ratio C is 0 or more is a configuration where the center - to - center distance La between the first part 61 and the second part 62 is greater than or equal to the center - to - center distance Lb between the third part 73 and the fourth part 74 (La ≧ Lb). Also, the configuration where the center - to - center distance ratio C is 1 or less is a configuration where the difference (La - Lb) between the center - to - center distance La and the center - to - center distance Lb is less than or equal to the outer dimension Db of the third part 73 or the fourth part 74.

[0083] In the second embodiment, the dimensions and positions of the respective elements of the movable coil 60 and the detection coil 70 are selected so that the center - to - center distance ratio C exceeds 0 and is less than 1 (0 < C < 1). That is, the center - to - center distance La exceeds the center - to - center distance Lb, and the difference (La - Lb) between them is less than the outer dimension Db.

[0084] In the second embodiment, since the center - to - center distance ratio C satisfies the above conditions, the speed variation amount Δ is less than the reference sample. Therefore, according to the second embodiment, it is possible to suppress a decrease in detection accuracy due to an error in the position between the movable coil 60 and the detection coil 70 in the Y - axis direction as compared with the reference sample.

[0085] In the above explanation, a comparison with a reference sample has been assumed, but in an actual product, it is desirable that the speed fluctuation amount Δ be a value of 5 or less. As can be seen from FIG. 12, the range of the center-to-center distance ratio C where the speed fluctuation amount Δ is 5 or less is 0.3 or more and 0.85 or less. Based on the results of the above considerations, in the second embodiment, the dimensions and positions of each element of the moving coil 60 and the detection coil 70 are further selected so that the center-to-center distance ratio C is 0.3 or more and 0.85 or less (0.3≦C≦0.85). More specifically, the dimensions and positions of each element of the moving coil 60 and the detection coil 70 are selected so that the center-to-center distance ratio C is greater than 0.3 and less than 0.85 (0.3≦C≦0.85). <C<0.85)。

[0086] In the second embodiment, since the center-to-center distance ratio C satisfies the above condition, the speed fluctuation amount Δ is suppressed to a value equal to or less than 5. Therefore, according to the second embodiment, it is possible to sufficiently suppress a decrease in detection accuracy caused by a positional error between the moving coil 60 and the detection coil 70 in the Y-axis direction.

[0087] The relationship between the first and second embodiments will be further explained below. In the first embodiment, the dimensions and positions of the elements of the moving coil 60 and the detection coil 70 are selected so that the following first condition is satisfied. [First condition] 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. 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 is greater than the center-to-center distance Lb between the center O3 of the third portion 73 and the center O4 of the fourth portion 74. 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 Y-axis direction.

[0088] On the other hand, in the second embodiment, the dimensions and positions of each element of the moving coil 60 and the detection coil 70 are selected so that the following second condition is satisfied. [Second condition] The center-to-center distance ratio C, which is the difference (La-Lb) between the center-to-center distance La between the first portion 61 and the second portion 62 and the center-to-center distance Lb between the third portion 73 and the fourth portion 74, divided by the external dimension Db (Db3, Db4) of the third portion 73 or the fourth portion 74 in the Y-axis direction, is greater than or equal to 0 and less than or equal to 1.

[0089] The moving 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, the first condition does not have to be satisfied in the second embodiment. Specifically, in the second embodiment, a form in which the outer dimension Da exceeds the outer dimension Db (a form that does not satisfy condition 1A) is also assumed.

[0090] C: Modification Specific modified embodiments added to each of the above-mentioned embodiments are exemplified below. Two or more embodiments selected from the following examples may be appropriately combined as long as they are not mutually contradictory.

[0091] (1) In each of the above embodiments, the detection system 30 detects the displacement of the hammer mechanism 22. However, as will be described below, the object of detection by the detection system 30 is not limited to the hammer mechanism 22.

[0092] Fig. 13 is a schematic diagram focusing on one key 14 of a keyboard instrument 100. As illustrated in Fig. 13, a detected portion 32 is provided on each key 14. For example, a moving coil 60 is provided on the underside of each key 14. Furthermore, a signal generating portion 33 including a detection coil 70 is provided on a support structure 18. The moving coil 60 and the detection coil 70 face each other.

[0093] 14 is a schematic diagram illustrating a pedal mechanism 90 of a keyboard instrument 100. The pedal mechanism 90 includes a pedal 91 operated by a user with the foot, a support member 92 that supports the pedal 91, and an elastic body 93 that urges the pedal 91 upward in the vertical direction. In the above configuration, the detected unit 32 is mounted on the pedal 91. Specifically, the moving coil 60 is mounted on the lower surface of the pedal 91. Furthermore, the signal generating unit 33 including the detection coil 70 is mounted on the support member 92. The moving coil 60 and the detection coil 70 face each other.

[0094] Although the pedal mechanism 90 of the keyboard instrument 100 is illustrated in Fig. 14, a pedal mechanism used in an electric instrument such as an electric string instrument (e.g., an electric guitar) also employs a configuration similar to that of Fig. 14. The pedal mechanism used in an electric instrument is an effect pedal operated by a user to adjust various sound effects such as distortion or compressor.

[0095] In addition, while the above-described embodiments have been described with reference to the keyboard instrument 100, the application of the present disclosure is not limited to the above examples. For example, a configuration similar to that of each of the above-described embodiments may be employed to detect the position of an operator operated by a user when playing a wind instrument such as a woodwind instrument (e.g., a clarinet or a saxophone) or a brass instrument (e.g., a trumpet or a trombone).

[0096] As can be understood from the above examples, the elements on which the moving coil 60 is installed are collectively expressed as movable members that are displaced in response to playing actions. The movable members include performance operators such as the keys 14 or pedals 91 that are directly operated by the user, as well as structures such as the hammer mechanism 22 that are displaced in conjunction with the operation of the performance operators. However, the movable members in this disclosure are not limited to members that are displaced in response to playing actions. In other words, the movable members are collectively expressed as members that can be displaced regardless of the trigger that generates the displacement.

[0097] In addition, positional errors in the Y-axis direction may occur in the moving coil 60 and the detection coil 70 due to factors such as assembly errors of the keyboard instrument 100. When an error occurs in the positions of the moving coil 60 and the detection coil 70 in the Y-axis direction, an error in the output characteristics may become apparent. According to the present disclosure, since the speed fluctuation amount Δ can be suppressed as described above, it is possible to suppress a decrease in detection accuracy caused by positional errors in the Y-axis direction of the moving coil 60 and the detection coil 70.

[0098] Incidentally, in a configuration in which the angle between the moving coil 60 and the detection coil 70 changes during the process of displacement of the moving coil 60, an error in the output characteristics caused by an error in the position between the moving coil 60 and the detection coil 70 is particularly likely to become apparent. In other words, in a configuration in which the angle between the moving coil 60 and the detection coil 70 changes, there is a tendency for the speed fluctuation amount Δ in the detection error characteristics to be large. According to the present disclosure, since the speed fluctuation amount Δ can be suppressed as described above, it is particularly suitable for a configuration in which the moving coil 60 is installed on the hammer mechanism 22 that rotates in response to a performance operation, that is, a configuration in which the detection system 30 is used to detect the position of the hammer mechanism 22.

[0099] (2) In the second embodiment, the combination of the lower limit value (0, 0.3) and the upper limit value (0.85, 1) defining the range of the center-to-center distance ratio C may be changed as appropriate. For example, the center-to-center distance ratio C may be a value not less than 0 and not more than 0.85, or not less than 0.3 and not more than 1.

[0100] (3) In the above-described embodiments, the magnetic fields in opposite directions are generated in the first portion 61 and the second portion 62 of the movable coil 60. However, a magnetic field in the same direction may be 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.

[0101] In the above-described embodiments, the magnetic fields in opposite directions are generated in the third portion 73 and the fourth portion 74 of the detection coil 70, but a magnetic field in the same direction may be 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.

[0102] (4) In each of the above-described embodiments, the moving coil 60 is configured with two layers, the conductive pattern 371 and the conductive pattern 372, but the configuration of the moving coil 60 is not limited to the above examples. For example, the moving coil 60 may be configured with a single layer or three or more layers. Similarly, the detection coil 70 may be configured with a single layer or three or more layers.

[0103] (5) In each of the above-described embodiments, the planar shapes of the first portion 61 and the second portion 62 of the moving coil 60 and the third portion 73 and the fourth portion 74 of the detection coil 70 are rectangular. However, the planar shapes of the moving coil 60 and the detection coil 70 are not limited to the above examples.

[0104] 15, the planar shape of each of the first portion 61 and the second portion 62 of the moving coil 60 may be a polygonal shape (e.g., an octagonal shape) other than a rectangle. Similarly, the planar shape of each of the third portion 73 and the fourth portion 74 of the detection coil 70 may be a polygonal shape (e.g., an octagonal shape) other than a rectangle.

[0105] 16, the planar shape of each of the first portion 61 and the second portion 62 of the moving coil 60 may be a circular shape (e.g., a perfect circle, an ellipse, or an oval shape). Similarly, the planar shape of each of the third portion 73 and the fourth portion 74 of the detection coil 70 may be a circular shape (e.g., a perfect circle, an ellipse, or an oval shape).

[0106] 17, the planar shape of each of the first portion 61 and the second portion 62 of the moving coil 60 may be a polygonal shape whose diagonal line runs along the Y-axis. Similarly, the planar shape of each of the third portion 73 and the fourth portion 74 of the detection coil 70 may be a polygonal shape whose diagonal line runs along the Y-axis.

[0107] As can be understood from the examples of Figures 15 to 17, regardless of the planar shapes of the moving coil 60 and the detection coil 70, the dimensions of each part of the moving coil 60 and the detection coil 70 satisfy the conditions exemplified in each of the above-mentioned embodiments.

[0108] For example, regardless of the planar shape of the moving 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 Db (Db3, Db4) is the same as in each of the above-mentioned embodiments.

[0109] Moreover, the 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, regardless of the planar shape of the moving coil 60. Similarly, 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 Y-axis direction, regardless of the planar shape of the detection coil 70. The relationship between the center-to-center distance La and the center-to-center distance Lb is the same as in each of the above-mentioned embodiments. Moreover, the preferable range of the center-to-center distance ratio C is the same as that exemplified in the second embodiment.

[0110] Regardless of the planar shapes of the moving coil 60 and the detection coil 70, the portion P1 of the first portion 61 located on the opposite side to the second portion 62 is located outside the third portion 73 in a planar view. Similarly, regardless of the planar shapes of the moving coil 60 and the detection coil 70, the portion P2 of the second portion 62 located on the opposite side to the first portion 61 is located outside the fourth portion 74 in a planar view.

[0111] (6) In the above-described embodiments, the outer dimension Da1 of the first portion 61 and the outer dimension Da2 of the second portion 62 are equal (Da1=Da2=Da), but the outer dimension Da1 and the outer dimension Da2 may be different. Specifically, a configuration in which the outer dimension Da1 exceeds the outer dimension Da2, or a configuration in which the outer dimension Da2 exceeds the outer dimension Da1 is also possible.

[0112] Similarly, in each of the above-described embodiments, the external dimension Db3 of the third portion 73 and the external dimension Db4 of the fourth portion 74 are equal (Db3=Db4=Db) but the external dimension Db3 and the external dimension Db4 may be different. Specifically, a configuration in which the external dimension Db3 exceeds the external dimension Db4, or a configuration in which the external dimension Db4 exceeds the external dimension Db3, is also conceivable.

[0113] In a configuration in which the outer dimensions Da1 and Da2 are different, the relationship between the outer dimensions Da1 and Db4 and the relationship between the outer dimensions Da2 and Db3 are not important. That is, a configuration in which the outer dimensions Da1 are equal to or larger than the outer dimensions Db4 and a configuration in which the outer dimensions Da2 are equal to or larger than the outer dimensions Db3 are also assumed. Similarly, in a configuration in which the outer dimensions Db3 and Db4 are different, the relationship between the outer dimensions Da1 and Db4 and the relationship between the outer dimensions Da2 and Db3 are not important.

[0114] (7) In the above embodiments, an electronic musical instrument in which the sound source device 44 generates the audio signal V has been exemplified, but the above embodiments are also applicable to, for example, a natural keyboard instrument in which a sound source such as a string generates musical tones. In a natural keyboard instrument, the weight portion 222 in the above embodiments is replaced with a hammer for striking the strings. The above embodiments are also applicable to a keyboard instrument equipped with a string-striking mechanism, such as an automatic playing piano or a silent piano. In the above-exemplified keyboard instruments, the detection system 30 is used to detect the displacement of a movable member such as the key 14 or the hammer mechanism 22 (or the hammer). In this disclosure, a "musical instrument" is a device used to play music, and both electronic musical instruments and natural musical instruments are included in the "musical instrument".

[0115] (8) In the above embodiments, an upright type drive mechanism 20 is exemplified, but the above embodiments can be applied to a keyboard instrument having a grand piano type drive mechanism. The type of keyboard instrument to which the present disclosure is applicable is not limited to the piano. For example, the above embodiments can be applied to various keyboard instruments such as a celesta or a glockenspiel.

[0116] (9) The term "nth" (n is a natural number) in this application is used only as a formal and convenient label to distinguish each element 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 production, etc., based on the term "nth".

[0117] D: Notes From the above-described exemplary embodiments, the following configurations can be understood, for example.

[0118] [Aspect A] A detection system according to one aspect (Aspect A1) of the present disclosure comprises a displaceable first coil and a second coil that generates a magnetic field when a drive signal is supplied, and generates a detection signal according 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, the second coil includes a third portion facing the first portion and a fourth portion facing the second portion, a first outer dimension of the first portion in the direction of the first axis is equal to or smaller 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 is equal to or smaller 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 exceeds a second distance between the center of the third portion and the center of the fourth portion, and 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.

[0119] According to the above aspect, even if an error (vertical deviation) occurs in the position of the first coil and the second coil in the direction of the first axis, the occurrence of 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) due to the error is suppressed. In other words, it is possible to suppress a decrease in detection accuracy due to an error in the position of the first coil and the second coil in the direction of the first axis.

[0120] The state where the first part and the third part are "opposed" means that the central axis of each of the first part and the third part passes through the other. In other words, the state where the first part and the third part are "opposed" means that a plane perpendicular to the central axis of the first part faces a plane perpendicular to the central axis of the third part, and typically, the central axis of the first part and the central axis of the third part are parallel to each other.

[0121] It should be noted that the first and third parts do not necessarily face each other when the first coil is at any position within the movable range, and if the first and third parts face each other when the first coil is at a specific position within the movable range, the first and third parts are interpreted as "facing each other." It should also be noted that the entirety of one of the first and third parts does not necessarily face the other, and a part of one of the first and third parts may face the other. Although the above description focuses on the relationship between the first and third parts, the same applies to the relationship between the second and fourth parts.

[0122] The "external dimensions" of the first part in the direction of the first axis refer to the dimensions (size) of a closed figure (external shape) defined by the contour of the first part in the direction of the first axis, and can also be said to be the maximum dimension of the first part in the direction of the first axis. Also, the "center" of the first part refers to the center (centroid) of the closed figure defined by the contour of the first part. Although the above explanation focuses on the first part, the same applies to the second to fourth parts.

[0123] In a specific example (Aspect A2) of Aspect A1, 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 aspect, the effect of suppressing a decrease in detection accuracy caused by a position error between the first coil and the second coil in the first axis direction is particularly remarkable.

[0124] In a specific example of Aspect A1 or 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 aspects, the planar shapes of the first coil and the second coil are simplified.

[0125] In a specific example (Aspect A4) of any one of Aspects A1 to A3, the center of the first portion and the center of the third portion are located within a range where the first portion and the third portion overlap in a plan view, and 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 in a plan view. According to the above aspects, it is easier to generate an induced current in the first portion due to a magnetic field generated in the third portion compared to a configuration in which the center of one or both of the first portion and the third portion is located outside the overlapping range of the first portion and the third portion. Similarly, it is easier to generate an induced current in the second portion due to a magnetic field generated in the fourth portion compared to a configuration in which the center of one or both of the second portion and the fourth portion is located outside the overlapping range of the second portion and the fourth portion. Therefore, a detection signal that reflects the distance between the first coil and the second coil with high accuracy can be generated.

[0126] Note that the "within the range" where the first and third parts overlap includes not only the area inside the range, but also the periphery (contour) of the range. Therefore, a form in which the center of the first or third part is located on the line of the range where the first and third parts overlap also satisfies the requirement of "within the range." The same applies to the range where the second and fourth parts overlap.

[0127] In a specific example (Aspect A5) of any of Aspects A1 to A4, a part of the first portion located on the opposite side to the second portion is located outside the third portion in a plan view, and a part of the second portion located on the opposite side to the first portion is located outside the fourth portion in a plan view. In the above aspects, a decrease in detection accuracy caused by a positional error between the first coil and the second coil in the direction of the first axis can be suppressed compared to a mode in which the entire first portion is located inside the third portion in a plan view or a mode in which the entire second portion is located inside the fourth portion in a plan view.

[0128] In addition, in the above-mentioned aspect, it is easier to ensure the area of ​​the first and second portions compared to a configuration in which the entire first portion is located inside the third portion in a plan view and a configuration in which the entire second portion is located inside the fourth portion in a plan view, and therefore it is possible to generate a detection signal that reflects the distance between the first coil and the second coil with high accuracy.

[0129] In a specific example (A6) of any of Aspects A1 to A5, the dimension of the second coil in the direction of a second axis perpendicular to the first axis is greater than the dimension of the first coil in the direction of the second axis. In the above aspects, even if an error (lateral shift) occurs in the positions of the first coil and the second coil in the direction of the second axis, the occurrence of an error in the output characteristics of the detection signal due to the error is suppressed. In other words, it is possible to suppress a decrease in detection accuracy due to an error in the positions of the first coil and the second coil in the direction of the second axis.

[0130] In a specific example (Aspect A7) of any one of Aspects A1 to A6, the first distance is equal to or less than twice the second distance. In the above aspects, since the first distance is less than twice the second distance, it is possible to effectively suppress a decrease in detection accuracy caused by an error in the position of the first coil and the second coil in the direction of the second axis. In a more preferred aspect, the first distance is equal to or more than 1.4 times and equal to or less than 1.6 times the second distance.

[0131] In a specific example (Aspect A8) of any one of Aspects A1 to A7, the first outer dimension is 0.5 times or more the third outer dimension, and the second outer dimension is 0.5 times or more the fourth outer dimension. In the above aspects, the areas of the first and second parts are sufficiently secured. Therefore, a detection signal that reflects the distance between the first coil and the second coil with high accuracy can be generated.

[0132] In a specific example (Aspect A9) of any of Aspects A1 to A8, a center-to-center distance ratio (La-Lb) / Db obtained by dividing a difference (La-Lb) between the distance La between the center of the first portion and the center of the second portion and the 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 not less than 0 and not more than 1. In a specific example (Aspect A10) of Aspect A9, the center-to-center distance ratio (La-Lb) / Db is not less than 0.3 and not more than 0.85.

[0133] In a specific example (Aspect A11) of any of Aspects A1 to A10, the first coil is mounted on a movable member that is displaced in response to a performance operation. In a more specific example (Aspect A12), the movable member is a hammer mechanism that rotates in response to the performance operation. In a configuration in which the angle between the first coil and the second coil changes as the first coil is displaced, an error in the output characteristics caused by an error in the positions of the first coil and the second coil is likely to become apparent. Considering the above tendency, the present disclosure is particularly suitable for a configuration in which the first coil is mounted on a hammer mechanism that rotates in response to a performance operation, i.e., a configuration in which a detection system is used to detect the position of the hammer mechanism.

[0134] A musical instrument according to one aspect (A13) of the present disclosure is a musical instrument comprising a movable member that is displaced in response to a playing operation, and a detection system, the detection system comprising a first coil installed on the movable member, and a second coil that generates a magnetic field in response to a supply of a drive signal, and generates a detection signal according 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 facing the first portion and a fourth portion facing the second portion, A first outer dimension of the first part in the direction of the first axis is less than or equal to 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 or equal to a fourth outer dimension of the fourth part in the direction of the first axis, a first distance between a center of the first part and a center of the second part is greater than 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.

[0135] In a specific example (Aspect A14) of Aspect A13, the center-to-center distance ratio (La-Lb) / Db, which is the difference (La-Lb) between the distance La between the center of the first portion and the center of the second portion and the distance Lb between the center of the third portion and the center of the fourth portion, divided by the 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.

[0136] [Aspect B] A detection system according to one aspect (Aspect B1) of the present disclosure includes a displaceable first coil and a second coil that generates a magnetic field when supplied with a drive signal, and generates a detection signal according to a 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 facing the first portion and a fourth portion facing the second portion, and a center-to-center distance ratio (La-Lb) / Db, which is a numerical value obtained by dividing a difference (La-Lb) between 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, is equal to or greater than 0 and equal to or less than 1. In a specific example (Aspect B2) of Aspect B1, the center-to-center distance ratio (La-Lb) / Db is greater than 0 and less than 1.

[0137] According to the above aspect, even if an error (vertical deviation) occurs in the position of the first coil and the second coil in the direction of the first axis, the occurrence of 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) due to the error is suppressed. In other words, it is possible to suppress a decrease in detection accuracy due to an error in the position of the first coil and the second coil in the direction of the first axis.

[0138] In a specific example (Aspect B3) of Aspect B1, the center-to-center distance ratio (La-Lb) / Db is 0.3 or more and 0.85 or less. In a more specific aspect, the center-to-center distance ratio (La-Lb) / Db is greater than 0.3 and less than 0.85. According to the above aspect, even if an error (vertical deviation) occurs in the position of the first coil and the second coil in the first axis direction, the error is prevented from occurring 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). In other words, the deterioration of detection accuracy caused by the error in the position of the first coil and the second coil in the first axis direction can be sufficiently prevented.

[0139] In a specific example (Aspect B5) of any of Aspects B1 to B4, the first coil is installed in a hammer mechanism that rotates in response to a performance operation. In a configuration in which the angle between the first coil and the second coil changes as the first coil is displaced, an error in the output characteristics caused by an error in the positions of the first coil and the second coil is likely to become apparent. Considering the above tendency, the present disclosure is particularly suitable for a configuration in which the first coil is installed in a hammer mechanism that rotates in response to a performance operation, that is, a configuration in which a detection system is used to detect the position of the hammer mechanism.

[0140] A musical instrument according to one aspect (aspect B6) of the present disclosure is a musical instrument comprising a movable member that is displaced in response to a playing operation, and a detection system, the detection system comprising a first coil installed on the movable member, and a second coil that generates a magnetic field in response to a supply of a drive signal, and generates a detection signal according 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 facing the first portion and a fourth portion facing the second portion, and the detection signal in the direction of the first axis is generated by detecting the distance between the first coil and the second coil. A first outer dimension of a first portion is equal to or smaller 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 is equal to or smaller than 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 the difference (La-Lb) between the distance La between the center of the first portion and the center of the second portion and the distance Lb between the center of the third portion and the center of the fourth portion, divided by the 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 1. [Explanation of symbols]

[0141] 100...keyboard instrument, 10...keyboard unit, 12...key, 14...key, 18...support structure, 20...driving mechanism, 21...transmission mechanism, 22...hammer mechanism, 221...hammer shank, 222...weight portion, 223...holding member, 30...detection system, 31...magnetic sensor, 32...detected portion, 33...signal generating portion, 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 emission system, 60...movable 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...support member, 93...elastic body, 321...capacitive element, 331...input terminal, 332...output terminal, 333...resistive element, 334, 335...capacitive elements, 351...supply circuit, 352...output circuit, 371, 372, 381, 382...conductive pattern, 611, 612, 621, 622, 731, 732, 741, 742...winding portion.

Claims

1. a displaceable first coil; a second coil that generates a magnetic field in response to a drive signal; A detection system that generates a detection signal according to a 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 facing the first portion and a fourth portion facing 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 a center of the first portion and a center of the second portion is greater than a second distance between a center of the third portion and a 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. Detection system.

2. the first outer dimension is less than the third outer dimension; The second outer dimension is smaller than the fourth outer dimension. The detection system of claim 1 .

3. the first outer dimension and the second outer dimension are equal; The third outer dimension and the fourth outer dimension are equal to each other. The detection system of claim 2.

4. a center of the first portion and a center of the third portion are located within a range where the first portion and the third portion overlap in a plan view, A center of the second portion and a center of the fourth portion are located within a range where the second portion and the fourth portion overlap in a plan view. The detection system of claim 1 .

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

6. A dimension of the second coil in a direction of a second axis perpendicular to the first axis is greater than a dimension of the first coil in the direction of the second axis. The detection system of claim 1 .

7. The first distance is less than or equal to twice the second distance. The detection system of claim 1 .

8. the first outer dimension is 0.5 times or more the third outer dimension, The second outer dimension is equal to or greater than 0.5 times the fourth outer dimension. The detection system of claim 1 .

9. A center-to-center distance ratio (La-Lb) / Db, which is a numerical value obtained by dividing a difference (La-Lb) between 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 equal to or greater than 0 and equal to or less than 1. The detection system of claim 1 .

10. The center distance ratio (La-Lb) / Db is 0.3 or more and 0.85 or less. The detection system of claim 9.

11. The first coil is disposed on a movable member that is displaced in response to a playing operation. The detection system of claim 1 .

12. The movable member is a hammer mechanism that rotates in response to the playing operation. The detection system of claim 11.

13. A movable member that is displaced in response to a performance operation; a detection system, The detection system comprises: A first coil disposed on the movable member; a second coil that generates a magnetic field in response to a drive signal; generating a detection signal according to a 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 facing the first portion and a fourth portion facing 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 a center of the first portion and a center of the second portion is greater than a second distance between a center of the third portion and a 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. musical instrument.

14. A center-to-center distance ratio (La-Lb) / Db, which is a numerical value obtained by dividing a difference (La-Lb) between 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 equal to or greater than 0 and equal to or less than 1.

14. The musical instrument of claim 13.

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