Detection Systems and Instruments

Abstract

To ease restrictions on arrangement of coils used to specify a position of a movable member.SOLUTION: A signal generator 27 includes a drive surface Fa in which a drive region Q-1, a drive region Q-2, and a drive region Q-3 are arranged in sequence in a direction of an X axis. A detection coil Lb-1 is installed on a key with a winding axis c along the X axis, and moves with the key in a direction of a Z axis between the drive region Q-1 and the drive region Q-2 in plan view. A detection coil Lb-2 is installed on the key with the winding axis c along the X axis, and moves with the key in the direction of the Z axis between the drive region Q-2 and the drive region Q-3 in plan view. The signal generator 27 generates a detection signal D-1 corresponding to a distance between the detection coil Lb-1 and the drive surface Fa by generating a magnetic field B-1 across the drive region Q-1 and the drive region Q-2 during a first drive period, and generates a detection signal D-2 corresponding to a distance between the detection coil Lb-2 and the drive surface Fa by generating a magnetic field across the drive region Q-2 and the drive region Q-3 during a second drive period that is different from the first drive period.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to techniques for determining the position of a movable member. [Background technology]

[0002] Various techniques for identifying the position of a movable part have been proposed. For example, Patent Document 1 discloses a detection system that includes an active resonant circuit installed on the body of a keyboard instrument and a passive resonant circuit installed on each key. The active resonant circuit includes a coil that generates a magnetic field when supplied with a periodic signal, and generates a detection signal corresponding to the distance between the active resonant circuit coil and the coil of the passive resonant circuit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 122867 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration of Patent Document 1, the coil of the active resonant circuit and the coil of the passive resonant circuit need to face each other. That is, there is a problem that the positional relationship between the coil of the active resonant circuit and the coil of the passive resonant circuit or the direction in which the coil of the passive resonant circuit moves is restricted. In consideration of the above circumstances, one aspect of the present disclosure aims to alleviate restrictions on the arrangement of coils used to identify the position of a movable member. [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 signal generating unit including a drive surface in which a first drive region, a second drive region, and a third drive region are arranged in order in a first direction; a first detection coil that is installed on a first movable member with its winding axis aligned with the first direction and that moves together with the first movable member in a second direction intersecting the first direction between the first drive region and the second drive region in a planar view; and a second detection coil that is installed on a second movable member with its winding axis aligned with the first direction and that moves together with the second movable member in the second direction between the second drive region and the third drive region in a planar view; wherein the signal generating unit generates a magnetic field across the first drive region and the second drive region in a first drive period to generate a first detection signal corresponding to the distance between the first detection coil and the drive surface, and generates a magnetic field across the second drive region and the third drive region in a second drive period separate from the first drive period to generate a second detection signal corresponding to the distance between the second detection coil and the drive surface.

[0006] A musical instrument according to one aspect of the present disclosure includes a first movable member and a second movable member that move in response to a performance operation by a user; a signal generating unit including a drive surface on which a first drive region, a second drive region, and a third drive region are arranged in order in a first direction; a first detection coil that is installed on the first movable member with its winding axis aligned along the first direction and that moves together with the first movable member in a second direction intersecting the first direction between the first drive region and the second drive region in a planar view; The drive circuit includes a second detection coil that is installed on the second movable member with its winding axis aligned along the first direction and that moves in the second direction together with the second movable member between the second drive region and the third drive region in a planar view, and the signal generation unit generates a magnetic field across the first drive region and the second drive region during a first drive period to generate a first detection signal corresponding to the distance between the first detection coil and the drive surface, and generates a magnetic field across the second drive region and the third drive region during a second drive period separate from the first drive period to generate a second detection signal corresponding to the distance between the second detection coil and the drive surface. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a block diagram illustrating the configuration of a keyboard instrument according to a first embodiment. [Figure 2] FIG. 1 is a schematic diagram illustrating the configuration of a keyboard instrument. [Figure 3] FIG. 2 is a circuit diagram of a magnetic field generating unit and a detected unit. [Figure 4] FIG. [Figure 5] FIG. 5 is a cross-sectional view taken along line aa in FIG. [Figure 6] 10 is a perspective view illustrating an example of the relationship between a signal generating unit and each detected unit. FIG. [Figure 7] 10 is a plan view illustrating an example of the relationship between a signal generating unit, each detection target unit, and each key. FIG. [Figure 8] FIG. 2 is an explanatory diagram of the operation of the detection system. [Figure 9] FIG. 2 is a plan view illustrating the configuration of a signal generating unit. [Figure 10] FIG. 10 is a cross-sectional view taken along the line bb in FIG. 9. [Figure 11] FIG. 2 is a block diagram illustrating the configuration of a drive circuit. [Figure 12] 10 is a flowchart of a control process. [Figure 13] FIG. 10 is an explanatory diagram of the operation for identifying the positions of two adjacent keys. [Figure 14] FIG. 10 is an explanatory diagram of the operation for identifying the positions of two adjacent keys. [Figure 15] FIG. 10 is a plan view of a signal generating unit in the second embodiment. [Figure 16] FIG. 10 is an explanatory diagram of the operation of detecting the position of one key in the second embodiment. [Figure 17] FIG. 10 is an explanatory diagram of the operation for identifying the positions of two adjacent keys in the second embodiment. [Figure 18] FIG. 10 is an explanatory diagram of the operation for identifying the positions of two adjacent keys in the second embodiment. [Figure 19]FIG. 11 is a plan view of a signal generating section in the third embodiment. [Figure 20] FIG. 20 is a cross-sectional view taken along the line cc in FIG. [Figure 21] FIG. 11 is a cross-sectional view of a detection system according to a modified example of the third embodiment. [Figure 22] FIG. 11 is a cross-sectional view of a detection system according to a modified example of the third embodiment. [Figure 23] 10A and 10B are perspective views illustrating the relationship between a signal generating section and each detected section in a modified example. [Figure 24] 10A and 10B are perspective views illustrating the relationship between a signal generating section and each detected section in a modified example. [Figure 25] FIG. 10 is a schematic diagram of a string-striking mechanism in a modified example. [Figure 26] FIG. 10 is a schematic diagram of a pedal mechanism according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] A: First embodiment FIG. 1 is a block diagram illustrating the configuration of a keyboard instrument 100 according to a first embodiment of the present disclosure. The keyboard instrument 100 is an electronic musical instrument comprising a keyboard unit 20, a control system 30, and a sound output system 40. In the following description, three mutually orthogonal axes (X-axis, Y-axis, and Z-axis) are assumed. The X-axis is an axis extending in the left-right direction (width direction) of the keyboard instrument 100. The Y-axis is an axis extending in the front-back direction (depth direction) of the keyboard instrument 100. In other words, the XY plane is parallel to the horizontal plane. The Z-axis is an axis extending in the up-down direction (vertical direction) of the keyboard instrument 100. The direction of the X-axis is an example of a "first direction."

[0009] The keyboard unit 20 is an input device that accepts performance operations by a user, and includes a keyboard 21 and a detection system 25. The keyboard 21 is composed of N keys 22-1 to 22-N (N is a natural number greater than or equal to 2) that correspond to different pitches. The N keys 22-1 to 22-N include multiple white keys and multiple black keys, and are arranged along the X axis. Each key 22-n (n = 1 to N) is configured as an elongated member that extends along the Y axis and moves in the direction of the Z axis in response to performance operations by the user. Performance operations include key pressing and key release. The detection system 25 identifies the position Pn of each key 22-n in the direction of the Z axis.

[0010] The control system 30 generates an audio signal V according to the result of detection by the detection system 25. The audio signal V is a signal representing a musical tone having a pitch corresponding to the key 22-n operated by the user. The control system 30 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 30.

[0011] The sound emission system 40 emits musical sounds 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 40. Note that the sound emission system 40 configured separately from the keyboard instrument 100 may be connected to the keyboard instrument 100 by wire or wirelessly.

[0012] 2 is a schematic diagram illustrating the configuration of a keyboard instrument 100. Each key 22-n of a keyboard 21 is supported by a support 24 with a balance pin 23 as a fulcrum. The support 24 is a structure that supports each element of the keyboard instrument 100. The tip of each key 22-n moves in the direction of the Z axis in response to a user's performance manipulation. A detection system 25 generates an observation signal O that represents a position Pn of each of the N keys 22-1 to 22-N. The position Pn is, for example, the surface position of the tip of the key 22-n, and is expressed as the amount of movement based on the position of each key 22-n when it is not being manipulated.

[0013] The detection system 25 includes a signal generating unit 27, N detection target units 60-1 to 60-N, and a drive circuit 70. The signal generating unit 27 is mounted on the support 24. That is, the position of each signal generating unit 27 is fixed. A detection target unit 60-n is mounted for each key 22-n. Specifically, the detection target unit 60 is mounted on the bottom surface 221 of the key 22-n. Therefore, the position of the detection target unit 60-n in the Z-axis direction changes in response to the performance operation by the user.

[0014] The signal generating unit 27 includes N magnetic field generating units 50-1 to 50-N corresponding to different keys 22-n. Each of the N magnetic field generating units 50-1 to 50-N includes a driving coil La-n that generates a magnetic field around it. On the other hand, each detected unit 60-n includes a detection coil Lb-n. That is, a pair of a driving coil La-n and a detection coil Lb-n is provided for each key 22-n. The distance between the magnetic field generating unit 50-n and the detected unit 60-n (the distance between the driving coil La-n and the detection coil Lb-n) varies depending on the position Pn of the key 22-n. In the first embodiment, the detected unit 60-n is provided between the front end of the key 22-n and the balance pin 23. Therefore, when the user presses a key, the distance between the driving coil La-n and the detection coil Lb-n decreases. The driving circuit 70 generates an observation signal O having a signal level corresponding to the distance between the driving coil La-n and the detection coil Lb-n.

[0015] 3 is a circuit diagram illustrating the electrical configuration of a magnetic field generating unit 50-n and a detection target unit 60-n corresponding to any one key 22-n. The magnetic field generating unit 50-n is a resonant circuit including, in addition to the drive coil La-n described above, an input terminal T1, an output terminal T2, a resistive element R, a capacitive element Ca1, and a capacitive element Ca2. One end of the resistive element R is connected to the input terminal T1, and the other end of the resistive element R is connected to one end of the capacitive element Ca1 and one end of the drive coil La-n. The other end of the drive coil La-n is connected to the output terminal T2 and one end of the capacitive element Ca2. The other end of the capacitive element Ca1 and the other end of the capacitive element Ca2 are grounded (Gnd).

[0016] The detected unit 60-n is a resonant circuit including a detection coil Lb-n and a capacitance element Cb. One end of the detection coil Lb-n is connected to one end of the capacitance element Cb, and the other end of the detection coil Lb-n is connected to the other end of the capacitance element Cb. In the first embodiment, the resonant frequency of the magnetic field generating unit 50-n and the resonant frequency of the detected unit 60-n are set to be equal to each other. However, the resonant frequency of the magnetic field generating unit 50-n and the resonant frequency of the detected unit 60-n may be different. For example, the resonant frequency of the magnetic field generating unit 50-n is set to a frequency obtained by multiplying the resonant frequency of the detected unit 60-n by a predetermined constant.

[0017] In the above configuration, a drive signal Wn is supplied to the input terminal T1 of the magnetic field generating unit 50-n. The drive signal Wn is a signal whose signal level fluctuates periodically. For example, a periodic signal with an arbitrary waveform, such as a sine wave or a square wave, is used as the drive signal Wn. The frequency of the drive signal Wn is set to a frequency approximately equal to the resonant frequency of the magnetic field generating unit 50-n and the detected unit 60-n.

[0018] The drive signal Wn is supplied to the drive coil La-n via the input terminal T1 and the resistive element R. The supply of the drive signal Wn generates a magnetic field Bn in the drive coil La-n. The magnetic field Bn generated in the drive coil La-n generates an induced current in the detection coil Lb-n of the detected unit 60-n due to electromagnetic induction. That is, a magnetic field is generated in the detection coil Lb-n in a direction that offsets the change in the magnetic field Bn of the drive coil La-n. The magnetic field generated in the detection coil Lb-n changes depending on the distance between the drive coil La-n and the detection coil Lb-n. Therefore, a detection signal Dn with an amplitude δ corresponding to the distance between the drive coil La-n and the detection coil Lb-n is output from the output terminal T2. The detection signal Dn is a periodic signal with the same frequency as the drive signal W. The amplitude δ of the detection signal Dn changes depending on the position Pn of the key 22-n.

[0019] FIG. 4 is a plan view of the detected portion 60-n, and FIG. 5 is a cross-sectional view taken along line aa in FIG. 4. Each detected portion 60-n includes a substrate 61. The substrate 61 is, for example, a rigid insulating substrate formed in a rectangular shape. The detection coil Lb-n is composed of a conductive pattern 621 formed on one surface of the substrate 61 and a conductive pattern 622 formed on the other surface of the substrate 61. Each of the conductive patterns 621 and 622 is a conductive film formed in a spiral shape that spirals from the inner circumference to the outer circumference around a winding axis c. The winding axis c is an axis perpendicular to the surface of the substrate 61 and corresponds to the central axis of the detection coil Lb-n. The detection coil Lb-n is configured by mutual conduction between the conductive patterns 621 and 622 via a conduction hole H. The conduction hole H is a through-hole formed in the substrate 61. A capacitance element Cb connected to the detection coil Lb-n is mounted on the substrate 61. The base material 61 may be made of a flexible insulating film.

[0020] Fig. 6 is a perspective view illustrating an example of the relationship between signal generating unit 27 and N detection target units 50-1 to 50-N. Fig. 7 is a plan view illustrating an example of the relationship between signal generating unit 27, N detection target units 50-1 to 50-N, and N keys 22-1 to 22-N.

[0021] The signal generating unit 27 includes a drive surface Fa. The drive surface Fa is a plane parallel to the XY plane. (N+1) drive areas Q-1 to Q-N+1 are defined on the drive surface Fa. The (N+1) drive areas Q-1 to Q-N+1 are arranged in the above order along the X axis. Specifically, the drive area Q-1 is located at the end of the keyboard 21 in the negative direction of the X axis, and the drive area Q-N+1 is located at the end of the keyboard 21 in the positive direction of the X axis.

[0022] As illustrated in FIG. 7, one key 22-n of the keyboard 21 is installed so as to partially overlap the drive area Qn and the drive area Q-n+1. The detection coil Lb-n of the detected part 60-n is located between the adjacent drive areas Qn and Q-n+1 in a plan view along the Z axis (hereinafter simply referred to as "plan view"). The detected part 60-n is installed on the key 22-n with the winding axis c of the detection coil Lb-n aligned along the X axis. In other words, the thickness direction of the substrate 61 is parallel to the X axis.

[0023] In the above configuration, the detection coil Lb-n moves in the Z-axis direction in conjunction with the key 22-n between the drive areas Qn and Q-n+1 in a plan view, as illustrated in Fig. 6. Specifically, when the key 22-n is pressed, the detection coil Lb-n approaches the drive surface Fa along the Z-axis, and when the key 22-n is released, the detection coil Lb-n moves away from the drive surface Fa along the Z-axis.

[0024] FIG. 8 is an explanatory diagram of the operation of the detection system 25. The period during which the detection system 25 operates is divided into N drive periods G-1 to GN corresponding to different keys 22-n. Each drive period Gn is set to a length sufficiently short compared to the time required for a user to press or release a key. Furthermore, the cycle of the drive signal Wn is sufficiently shorter than the length of one drive period Gn. Any one drive period Gn is a period for identifying the position Pn of one key 22-n of the keyboard 21. That is, in each of the N drive periods G-1 to GN, the position Pn of each key 22-n is detected sequentially in a time-division manner. The N drive periods G-1 to GN are repeated on the time axis.

[0025] In each drive period Gn, a magnetic field Bn is generated across drive region Qn and drive region Q-n+1. FIG. 6 illustrates a magnetic field B-1 extending from drive region Q-1 to drive region Q-2. As explained above, in each of the N drive periods G-1 to GN, a magnetic field Bn extending from drive region Qn to drive region Q-n+1 is generated sequentially on the drive surface Fa. For example, in drive period G-1, a magnetic field B-1 is generated extending from drive region Q-1 to drive region Q-2, in drive period G-2, a magnetic field B-2 is generated extending from drive region Q-2 to drive region Q-3, and so on. In drive period GN, a magnetic field BN is generated extending from drive region QN to drive region Q-N+1.

[0026] The magnetic field Bn includes a component along the X-axis. The detection coil Lb-n of each detected portion 60-n moves in the direction of the Z-axis, crossing the magnetic field Bn. Therefore, as described above, an induced current is generated in the detection coil Lb-n due to electromagnetic induction caused by the magnetic field Bn generated in the drive coil La-n. Utilizing the magnetic field changes exemplified above, a detection signal Dn with an amplitude δ corresponding to the distance between the drive coil La-n and the detection coil Lb-n is generated.

[0027] FIG. 9 is a plan view illustrating a detailed configuration of the signal generating unit 27, and FIG. 10 is a cross-sectional view taken along line bb in FIG. 9. The signal generating unit 27 includes a base material 51. The base material 51 is, for example, a hard insulating substrate. Specifically, the base material 51 is a plate-like member that is elongated in the X-axis direction across the N magnetic field generating units 50-1 to 50-N. The base material 51 includes a drive surface Fa and a mounting surface Fb. The drive surface Fa and the mounting surface Fb are surfaces opposite each other. The drive surface Fa is the surface of the base material 51 that faces the detection target unit 60-n, and the mounting surface Fb is the surface of the base material 51 that faces the support 24. Note that, for convenience, the resistive element R and the capacitive elements Ca1 and Ca2 are omitted from FIGS. 9 and 10. The base material 51 may be made of a flexible insulating film.

[0028] A conductive pattern 521 is formed on the driving surface Fa of the substrate 51. For example, the conductive pattern 521 is formed by patterning a conductive film that covers the entire driving surface Fa. On the other hand, a conductive pattern 522 is formed on the mounting surface Fb of the substrate 51. For example, the conductive pattern 522 is formed by patterning a conductive film that covers the entire mounting surface Fb.

[0029] Of the N magnetic field generation units 50-1 to 50-N, each odd-numbered magnetic field generation unit 50-n1 (n1=1, 3, 5, ...) is installed on the driving surface Fa. The driving coil La-n1, input terminal T1, and output terminal T2 of each magnetic field generation unit 50-n1 are included in the conductive pattern 521 of the driving surface Fa.

[0030] Each odd-numbered drive coil La-n1 includes a first portion A1 and a second portion A2. The first portion A1 and the second portion A2 are arranged in the direction of the X-axis. Specifically, the second portion A2 is located in the positive direction of the X-axis when viewed from the first portion A1. The first portion A1 is formed in a spiral shape that spirals counterclockwise from the inner periphery to the outer periphery in a plan view. On the other hand, the second portion A2 is formed in a spiral shape that spirals clockwise from the inner periphery to the outer periphery in a plan view. The center of the first portion A1 and the outer periphery of the second portion A2 are electrically connected.

[0031] The first portion A1 of the drive coil La-n1 is located in the drive region Q-n1, and the second portion A2 of the drive coil La-n1 is located in the drive region Q-n1+1, i.e., the first portion A1 and the second portion A2 of each drive coil La-n1 are alternately arranged along the X-axis.

[0032] Each magnetic field generating unit 50-n1 includes a switch Ha and a switch Hb disposed on the driving surface Fa. The switch Ha is disposed between the first portion A1 and the input terminal T1 and switches between conduction and insulation therebetween. The switch Hb is disposed between the second portion A2 and the output terminal T2 and switches between conduction and insulation therebetween.

[0033] In the above configuration, when a drive signal W-n1 is supplied to the input terminal T1 while the switches Ha and Hb are maintained in the on state, a current flows through the drive coil La-n1. When a current in a first current direction α1 flows through the first portion A1, a current in a second current direction α2 opposite to the first current direction α1 flows through the second portion A2. In other words, currents flow in opposite directions through the first portion A1 and the second portion A2. Therefore, magnetic fields in opposite directions are generated in the first portion A1 and the second portion A2. As a result of the above action, a magnetic field B-n1 is generated across the drive region Q-n1 and the drive region Q-n1+1, as described above. Therefore, a detection signal D-n1 with an amplitude δ corresponding to the distance between the drive coil La-n1 and the detection coil Lb-n1 passes through the switch Hb and is output from the output terminal T2.

[0034] On the other hand, each of the even-numbered magnetic field generation units 50-n2 (n1=2, 4, 6, ...) among the N magnetic field generation units 50-1 to 50-N is placed on the installation surface Fb. The drive coil La-n2, input terminal T1, and output terminal T2 of each magnetic field generation unit 50-n2 are included in the conductive pattern 522 on the installation surface Fb.

[0035] The drive coil La-n2 includes a third portion A3 and a fourth portion A4. The third portion A3 and the fourth portion A4 are arranged in the direction of the X-axis. Specifically, the fourth portion A4 is located in the positive direction of the X-axis when viewed from the third portion A3. The third portion A3 is formed in a spiral shape that spirals counterclockwise from the inner periphery to the outer periphery in a plan view. On the other hand, the fourth portion A4 is formed in a spiral shape that spirals clockwise from the inner periphery to the outer periphery in a plan view. The center of the third portion A3 and the outer periphery of the fourth portion A4 are electrically connected.

[0036] The third portion A3 of the drive coil La-n2 is located in the drive region Q-n2, and the fourth portion A4 of the drive coil La-n2 is located in the drive region Q-n2+1, i.e., the third portion A3 and the fourth portion A4 of each drive coil La-n2 are alternately arranged along the X-axis.

[0037] As can be understood from the above description, the drive coils La-n1 and Lb-n2 overlap each other in a planar view. Specifically, the second portion A2 and the third portion A3 overlap each other within the drive region Q-n2, and the first portion A1 and the fourth portion A4 overlap each other within the drive region Q-n1. Therefore, the size of the signal generating unit 27 can be reduced compared to a configuration in which the drive coils La-n1 and La-n2 do not overlap each other.

[0038] Each magnetic field generating unit 50-n2 includes a switch Ha and a switch Hb installed on the installation surface Fb. The switch Ha is installed between the third portion A3 and the input terminal T1 and switches between conduction and insulation therebetween. The switch Hb is installed between the fourth portion A4 and the output terminal T2 and switches between conduction and insulation therebetween.

[0039] In the above configuration, when a drive signal W-n2 is supplied to the input terminal T1 while the switches Ha and Hb are maintained in the on state, a current flows through the drive coil La-n2. When a current flows through the third portion A3 in the first current direction α1, a current flows through the fourth portion A4 in the second current direction α2. In other words, currents flow in opposite directions through the third portion A3 and the fourth portion A4. Therefore, magnetic fields in opposite directions are generated in the third portion A3 and the fourth portion A4. As a result of the above action, a magnetic field B-n2 is generated across the drive region Q-n2 and the drive region Q-n2+1, as described above. Therefore, a detection signal D-n2 with an amplitude δ corresponding to the distance between the drive coil La-n2 and the detection coil Lb-n2 passes through the switch Hb and is output from the output terminal T2.

[0040] 11 is a block diagram illustrating a specific configuration of the drive circuit 70. The drive circuit 70 includes a supply circuit 71 and an output circuit 72. During each drive period Gn, the supply circuit 71 controls the switches Ha and Hb of the magnetic field generation unit 50-n to be in the on state, and then supplies the drive signal Wn to the magnetic field generation unit 50-n. In other words, the supply circuit 71 is a demultiplexer that supplies the drive signal Wn to each magnetic field generation unit 50-n in a time-division manner. As described above, the magnetic field generation unit 50-n generates a magnetic field Bn in response to the supply of the drive signal Wn.

[0041] The output circuit 72 in FIG. 11 is a multiplexer that generates an observation signal O by arranging, on a time axis, the detection signals Dn output from each magnetic field generation unit 50-n for each drive period Gn. Specifically, the output circuit 72 rectifies (full-wave or half-wave rectification) and smoothes the detection signals Dn output from each magnetic field generation unit 50-n for each drive period Gn, and generates the observation signal O by arranging the smoothed signals for each drive period Gn on a time axis. As can be understood from the above explanation, the observation signal O is set to a signal level corresponding to the position Pn of each key 22-n for each drive period Gn. Specifically, the signal level of the observation signal O increases as the distance between the drive coil La-n and the detection coil Lb-n increases. The signal level of the observation signal O during each drive period Gn corresponds to the signal level of the detection signal Dn generated by the magnetic field generation unit 50-n during that drive period Gn.

[0042] 2 analyzes the position Pn of each key 22-n by analyzing the observation signal O supplied from the drive circuit 70. The control system 30 is realized by a computer system including a control device 31, a storage device 32, an A / D converter 33, and a sound source circuit 34. The control system 30 may be realized by a single device, or may be realized by multiple devices configured separately from each other.

[0043] The control device 31 is composed of one or more processors that control each element of the keyboard instrument 100. Specifically, the control device 31 is composed of one or more types of processors, such as a CPU (Central Processing Unit), a GPU (Graphics 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).

[0044] The storage device 32 is one or more memories that store programs executed by the control device 31 and data used by the control device 31. The storage device 32 is configured with a known storage medium such as a magnetic storage medium or a semiconductor storage medium. The storage device 32 may also be configured with a combination of multiple types of storage medium. The storage device 32 may also be a portable storage medium that can be attached to or detached from the keyboard instrument 100, or an external storage medium (e.g., online storage) with which the keyboard instrument 100 can communicate.

[0045] The A / D converter 33 converts the observation signal O supplied from the drive circuit 70 from analog to digital. The sound source circuit 34 generates an audio signal V representing a musical tone instructed by the control device 31. Specifically, the audio signal V represents a musical tone of a pitch corresponding to the key 22-n whose position Pn has changed among a plurality of pitches. The volume of the audio signal V is controlled, for example, according to the speed at which the position Pn changes. The audio signal V is supplied from the sound source circuit 34 to the sound emission system 40, whereby a musical tone corresponding to a performance operation by a user is emitted from the sound emission system 40. Note that the control device 31 may implement the function of the sound source circuit 34 by executing a program stored in the storage device 32. In other words, the element (sound source unit) that generates the audio signal V may be either a software sound source implemented by the general-purpose control device 31 or a hardware sound source implemented by a dedicated electronic circuit.

[0046] FIG. 12 is a flowchart of the process (hereinafter referred to as the "control process") executed by the control device 31. For example, the control process is repeated for each drive period Gn. When the control process starts, the control device 31 identifies the signal level of each detection signal Dn from the observation signal O converted by the A / D converter 33 (S1). The signal level within each drive period Gn is a voltage value corresponding to the amplitude δ of the detection signal Dn generated by the magnetic field generation unit 50-n during that drive period Gn. In other words, the signal level is set to a voltage value corresponding to the position Pn of one key 22-n corresponding to the drive period Gn.

[0047] The control device 31 identifies the position Pn of each key 22-n from the signal level of the detection signal Dn (S2). The position Pn is identified using a table that associates the signal level with the position Pn. Alternatively, the control device 31 may calculate the position Pn by a predetermined calculation that applies the signal level.

[0048] The control device 31 controls the tone generator circuit 34 in accordance with the position Pn of each key 22-n (S3). Specifically, the control device 31 determines whether or not each key 22-n has been pressed in accordance with the position Pn of each key 22-n, and instructs the tone generator circuit 34 to generate a musical tone corresponding to the key 22-n pressed by the user. The tone generator circuit 34 generates an audio signal V representing the musical tone instructed by the control device 31.

[0049] 13 and 14 are explanatory diagrams of the operation for identifying the position Pn of each of two adjacent keys 22-n (22-n1, 22-n2). Figures 13 and 14 show drive regions Q-n1, Q-n2, and Q-n3. Drive regions Q-n1, Q-n2, and Q-n3 are arranged in the above order in the positive direction of the X-axis.

[0050] The detection coil Lb-n1 installed in the key 22-n1 moves in the Z-axis direction together with the key 22-n1 between the drive areas Q-n1 and Q-n2. The detection coil Lb-n2 installed in the key 22-n2 moves in the Z-axis direction together with the key 22-n2 between the drive areas Q-n2 and Q-n3.

[0051] 13, during the drive period G-n1, the signal generation unit 27 (magnetic field generation unit 50-n1) generates a magnetic field B-n1 across drive regions Q-n1 and Q-n2, thereby generating a detection signal D-n1 corresponding to the distance between the detection coil Lb-n1 and the drive surface Fa. Specifically, the drive coil La-n1 generates the detection signal D-n1 from the drive signal W-n1.

[0052] 14, during the drive period G-n2, the signal generator 27 (magnetic field generator 50-n2) generates a magnetic field B-n2 across the drive regions Q-n2 and Q-n3, thereby generating a detection signal D-n2 according to the distance between the detection coil Lb-n2 and the drive surface Fa. Specifically, the drive coil La-n2 generates the detection signal D-n2 from the drive signal W-n2.

[0053] In the above description, the drive region Q-n1 is an example of a "first drive region," the drive region Q-n2 is an example of a "second drive region," and the drive region Q-n3 is an example of a "third drive region." Furthermore, the key 22-n1 is an example of a "first movable member," and the key 22-n2 is an example of a "second movable member." The detection coil Lb-n1 is an example of a "first detection coil," and the detection coil Lb-n2 is an example of a "second detection coil." The drive period G-n1 is an example of a "first drive period," and the drive period G-n2 is an example of a "second drive period."

[0054] As described above, in the first embodiment, the detection coil Lb-n moves across two adjacent drive regions Q (Qn, Q-n+1). Therefore, compared to a configuration in which the winding axis c of the detection coil Lb-n is perpendicular to the drive plane Fa, restrictions on the direction of movement of the detection coil Lb-n relative to the drive plane Fa (drive coil La-n) can be relaxed. Specifically, the direction of movement of the detection coil Lb-n relative to the drive plane Fa can be set to any direction within the plane between the two adjacent drive regions Q. For example, the detection coil Lb-n may move in a direction intersecting (e.g., perpendicular to) the drive plane Fa, as shown in FIG. 6, or in a direction parallel to the drive plane Fa, as shown in FIG. 24 (discussed later).

[0055] In the configuration of Patent Document 1, the coil of the active resonant circuit and the coil of the passive resonant circuit are arranged to face each other. However, there is room for various improvements in terms of improving the accuracy of identifying the position of the movable member. In the first embodiment, it is possible to sufficiently change the detection signal Dn depending on the distance between the detection coil Lb-n and the drive surface Fa. In other words, the position Pn of each key 22-n can be identified with high accuracy. Furthermore, in the first embodiment, the position Pn of each key 22-n can be identified with high accuracy through a simple configuration that selectively supplies a drive signal Wn to each of the N drive coils La-1 to La-N.

[0056] B: Second embodiment A second embodiment will be described. Note that, for elements in the following exemplary aspects that have the same functions as those in the first embodiment, the same reference numerals as those in the first embodiment will be used, and detailed descriptions of each will be omitted as appropriate.

[0057] 15 is a plan view illustrating the configuration of the signal generating unit 27 in the second embodiment. (N+1) driving regions Q-1 to Q-N+1 are defined on the driving surface Fa of the substrate 51 in the signal generating unit 27. The (N+1) driving regions Q-1 to Q-N+1 are arranged in the above order along the X axis. A driving coil La-n is installed in each driving region Qn. That is, (N+1) driving coils La-1 to La-N+1 are arranged in the above order along the X axis.

[0058] Of the (N+1) drive coils La-1 to La-N+1, each odd-numbered drive coil La-n1 (n1=1, 3, 5, ...) is formed into a spiral shape that spirals clockwise from the inner periphery to the outer periphery in plan view. On the other hand, each even-numbered drive coil La-n2 (n2=2, 4, 6, ...) of the (N+1) drive coils La-1 to La-N+1 is formed into a spiral shape that spirals counterclockwise from the inner periphery to the outer periphery in plan view. In other words, drive coils La-n1 and La-n2, which have winding directions opposite to each other, are arranged alternately along the X-axis.

[0059] A connection terminal Tn and a switch Ha-n and a switch Hb-n are provided for each of the (N+1) drive coils La-1 to La-N+1 on the substrate 51. The switch Ha-n corresponding to each drive coil La-n switches between electrical continuity and insulation between that drive coil La-n and the connection terminal Tn. Furthermore, the switch Hb-n corresponding to each drive coil La-n switches between electrical continuity and insulation between that drive coil La-n and the connection terminal T-n+1 of the next stage.

[0060] As illustrated in FIG. 16, during each drive period Gn, the drive circuit 70 controls the switches Ha-n and Hb-n corresponding to the drive coil La-n and the switches Ha-n+1 and Hb-n+1 corresponding to the drive coil La-n+1 in the next stage to the on state. In this state, a path is established from the connection terminal Tn to the switch Ha-n to the drive coil La-n to the switch Hb-n to the switch Ha-n+1 to the drive coil La-n+1 to the switch Hb-n+1 to the connection terminal T-n+1. In this state, the connection terminal Tn functions as the input terminal T1 in FIG. 3, and the connection terminal T-n+1 functions as the output terminal T2 in FIG. 3. The pair of the drive coil La-n and the drive coil La-n+1 constitutes the drive coil La-n in FIG. 3.

[0061] In the above state, the drive circuit 70 (supply circuit 71) supplies a drive signal Wn to the connection terminal Tn. Therefore, a current corresponding to the drive signal Wn flows through the drive coils La_n and La_n+1. As described above, since the winding directions of the drive coils La_n and La_n+1 are opposite, a current flows in the opposite directions through the drive coils La_n and La_n+1. That is, magnetic fields in opposite directions are generated in the drive coils La_n and La_n+1. Therefore, as in the first embodiment, during each drive period Gn, a magnetic field Bn is generated across the drive region Qn and the drive region Q-n+1. As in the first embodiment, the detection coil Lb-n of each detected portion 60-n moves in the direction of the Z axis so as to cross the magnetic field Bn. Therefore, a detection signal Dn with an amplitude δ corresponding to the distance between the drive surface Fa and the detection coil Lb-n is output from the connection terminal T-n+1 (output terminal T2). The above operations are repeated for each drive period Gn, and an observation signal O representing the signal level of each detection signal Dn is generated, as in the first embodiment. The configuration and operations for identifying the position Pn of each key 22-n by analyzing the observation signal O are the same as in the first embodiment.

[0062] 17 and 18 are explanatory diagrams of the operation for identifying the position Pn of each of two adjacent keys 22-n (22-n1, 22-n2). Fig. 17 shows drive regions Q-n1, Q-n2, and Q-n3. Drive regions Q-n1, Q-n2, and Q-n3 are arranged in the above order in the positive direction of the X-axis. Drive coil La-n1 is installed in drive region Q-n1, drive coil La-n2 is installed in drive region Q-n2, and drive coil La-n3 is installed in drive region Q-n3.

[0063] 17, the drive circuit 70 controls the switches Ha-n1, Hb-n1, Ha-n2, and Hb-n2 to the on state. That is, the drive coils La-n1 and La-n2 are electrically connected so that a current flows through the drive coil La-n1 in the first current direction α1 and a current flows through the drive coil La-n2 in the second current direction α2.

[0064] In the above state, the drive circuit 70 supplies a drive signal W-n1 to the connection terminal T-n1. A current corresponding to the drive signal W-n1 flows through the drive coils La-n1 and La-n2, and a detection signal D-n1 corresponding to the distance between the drive surface Fa and the detection coil Lb-n1 is output to the connection terminal T-n3. That is, the drive circuit 70 generates the detection signal D-n1 by supplying the drive signal W-n1 to the drive coils La-n1 and La-n2.

[0065] On the other hand, during the drive period G-n2 immediately following the drive period G-n1, the drive circuit 70 controls the switches Ha-n2, Hb-n2, Ha-n3, and Hb-n3 to the on state. That is, the drive coils La-n2 and La-n3 are electrically connected so that a current flows through the drive coil La-n2 in a third current direction α3 and a current flows through the drive coil La-n3 in a fourth current direction α4. The third current direction α3 is the same direction as one of the first current direction α1 and the second current direction α2, and the fourth current direction α4 is the same direction as the other of the first current direction α1 and the second current direction α2.

[0066] In the above state, the drive circuit 70 supplies a drive signal W-n2 to the connection terminal T-n2. A current corresponding to the drive signal W-n2 flows through the drive coils La-n2 and La-n3, and a detection signal D-n2 corresponding to the distance between the drive surface Fa and the detection coil Lb-n2 is output. That is, the drive circuit 70 generates the detection signal D-n2 by supplying the drive signal W-n2 to the drive coils La-n2 and La-n3.

[0067] In the above description, drive region Q-n1 is an example of a "first drive region," drive region Q-n2 is an example of a "second drive region," and drive region Q-n3 is an example of a "third drive region." Also, drive coil La-n1 is an example of a "first drive coil," drive coil La-n2 is an example of a "second drive coil," and drive coil La-n3 is an example of a "third drive coil." Drive period G-n1 is an example of a "first drive period," and drive period G-n2 is an example of a "second drive period."

[0068] The second embodiment also achieves the same effects as the first embodiment. Furthermore, in the second embodiment, the drive coil La-n2 is used to identify the position P-n1 of the key 22-n1 during the drive period G-n1 and to identify the position P-n2 of the key 22-n2 during the drive period G-n2. Therefore, compared to an embodiment in which a separate drive coil La-n is used to identify the position Pn of each key 22-n (e.g., the first embodiment), the number of drive coils La-n required to identify the position Pn of each key 22-n can be reduced. This, for example, can reduce the size of the signal generation unit 27.

[0069] C: Third embodiment Fig. 19 is a plan view of the signal generating unit 27 in the third embodiment. Fig. 20 is a cross-sectional view taken along line cc in Fig. 19. For convenience, Fig. 20 also shows the detection target unit 60-n and the key 22-n.

[0070] The signal generation unit 27 includes (N+1) drive coils La-1 to La-N+1 installed in different drive regions Q (Q-1 to Q-N+1). The (N+1) drive coils La-1 to La-N+1 are arranged in the direction of the X axis in a plan view. As in the first and second embodiments, the detection coil Lb-n installed in each key 22-n moves in the direction of the Z axis together with the key 22-n between the drive region Qn and the drive region Q-N+1.

[0071] The base material 51 of the third embodiment is a multilayer substrate in which a first layer 551, a second layer 552, a third layer 553, and a fourth layer 554 are stacked in this order in the positive direction of the Z axis. Each of the first layer 551, the second layer 552, the third layer 553, and the fourth layer 554 is, for example, a hard insulating substrate.

[0072] A plurality (N / 2) of conductive patterns 561 are formed on the surface of the first layer 551. A plurality (N / 2) of conductive patterns 562 are formed on the surface of the second layer 552. A plurality (N / 2) of conductive patterns 563 are formed on the surface of the third layer 553. A plurality (N / 2) of conductive patterns 564 are formed on the surface of the fourth layer 554. Each of the conductive patterns 56 (561 to 564) is formed in a spiral shape that spirals from the inner periphery to the outer periphery. The conductive patterns 561 and 563 overlap and are conductive with each other in a planar view. The conductive patterns 562 and 564 overlap and are conductive with each other in a planar view.

[0073] Of the N drive coils La-1 to La-N, each odd-numbered drive coil La-n1 (n1=1, 3, 5, ...) is configured by laminating a conductive pattern 561 and a conductive pattern 563. Of the N drive coils La-1 to La-N, each even-numbered drive coil La-n2 (n2=2, 4, 6, ...) is configured by laminating a conductive pattern 562 and a conductive pattern 564. The relationship between the (N+1) drive coils La-1 to La-N+1 is the same as in the first embodiment (FIG. 9) or the second embodiment (FIG. 15). Furthermore, the operation of the drive circuit 70 to drive each drive coil La-1 to La-N+1 is also the same as in the first or second embodiment.

[0074] The dimension of each conductive pattern 56 in the X-axis direction exceeds the distance between two adjacent conductive patterns 56 in the X-axis direction. Therefore, conductive patterns 561 and 563 and conductive patterns 562 and 564 partially overlap each other in a planar view. Specifically, a portion of conductive patterns 561 and 563 in the X-axis direction and a portion of conductive patterns 562 and 564 in the X-axis direction overlap each other in a planar view. As can be understood from the above explanation, drive coil La-n1 and drive coil La-n2, which are adjacent to each other in the X-axis direction, partially overlap each other in a planar view.

[0075] In a configuration in which the drive coils La-n1 and La-n2 do not overlap each other, the area in which each drive coil La-n can be installed is limited, making it difficult to generate a magnetic field Bn of sufficient strength in each drive coil La-n. According to the third embodiment, the drive coils La-n1 and La-n2 partially overlap each other in a plan view, making it possible to generate a magnetic field Bn of sufficient strength in each drive coil La-n1.

[0076] In the above description, as in the first and second embodiments, the winding axis c of the detector coil Lb-n is aligned along the X-axis. However, the configuration in which the drive coils La-n1 and La-n2 overlap in a plan view is not limited to this. For example, as illustrated in FIG. 21 , even in a configuration in which the detector coil Lb-n is positioned opposite the drive coil La-n, the configuration in which the drive coils La-n1 and La-n2 overlap in a plan view can be employed. In the configuration of FIG. 21 , the detector coil Lb-n is positioned on the key 22-n with its winding axis c aligned along the Z-axis. That is, the detector coil Lb-n moves in the direction of the winding axis c together with the key 22-n in response to a performance operation by the user.

[0077] 21, the supply circuit 71 of the drive circuit 70 supplies a drive signal Wn to each drive coil La-n in a time-division manner for each drive period Gn. The output circuit 72 acquires a detection signal Dn output from the drive coil La-n during each drive period Gn. The signal level of the detection signal Dn varies depending on the distance between the drive coil La-n and the detection coil Lb-n. Therefore, similar to the first and second embodiments, the control system 30 can identify the position Pn of each key 22-n by analyzing the observation signal O output by the output circuit 72.

[0078] 20 illustrates an example in which each odd-numbered drive coil La-n1 is configured by laminating a conductive pattern 561 and a conductive pattern 563, and each even-numbered drive coil La-n2 is configured by laminating a conductive pattern 562 and a conductive pattern 564, but the laminated structure of each drive coil La-n is not limited to this example. For example, as illustrated in FIG. 22, each odd-numbered drive coil La-n1 may be configured by laminating a conductive pattern 561 and a conductive pattern 562, and each even-numbered drive coil La-n2 may be configured by laminating a conductive pattern 563 and a conductive pattern 564. That is, each drive coil La-n may be configured by laminating conductive patterns adjacent to each other with a single layer (551 to 554) sandwiched between them.

[0079] 22, it is possible to reduce positional errors between conductive patterns 561 and 562 that form drive coil La-n1, and to reduce positional errors between conductive patterns 563 and 564 that form drive coil La-n2. Another advantage is that substrate 51 can be easily manufactured by joining first layer 551, on which conductive patterns 561 and 562 are formed, and third layer 553, on which conductive patterns 563 and 564 are formed, with second layer 552 sandwiched between them. Fourth layer 554 may be omitted.

[0080] Although FIG. 22 illustrates an example in which the winding axis c of detection coil Lb-n is aligned with the X-axis, in the configuration of FIG. 21 in which detection coil Lb-n is installed on key 22-n with the winding axis c aligned with the Z-axis, each odd-numbered drive coil La-n1 may be configured by laminating conductive pattern 561 and conductive pattern 562, and each even-numbered drive coil La-n2 may be configured by laminating conductive pattern 563 and conductive pattern 564.

[0081] D: Modification Specific modified embodiments that can be added to each of the above-described embodiments are exemplified below. Multiple embodiments arbitrarily selected from the above-described embodiments and the modified embodiments exemplified below may be combined as appropriate within the scope of not mutually contradicting each other.

[0082] (1) As illustrated in FIG. 23, N slits 58-1 to 58-N corresponding to different detection targets 60-n may be formed in the base material 51 of the signal generating unit 27. The slits 50-n are elongated through-holes sized to allow the detection targets 60-n to be inserted therein. That is, when the key 22-n is pressed all the way down, a portion of the detection target 60-n is inserted into the slit 50-n. The configuration of FIG. 23 reduces the possibility of collision between each detection target 60-n and the signal generating unit 27.

[0083] (2) In the above-described embodiments, the detected portion 60-n moves in the Z-axis direction. However, the direction in which the detected portion 60-n moves relative to the drive surface Fa is not limited to the above examples. For example, as illustrated in FIG. 24, the detected portion 60-n may also move in the Y-axis direction in response to a performance operation on each key 22-n. That is, the detected portion 60-n may move in a direction parallel to the drive surface Fa. Because a magnetic field Bn is formed on the drive surface Fa across the drive region Qn and the drive region Q-n+1, ​​in the configuration of FIG. 24, as in the first and second embodiments, the detected portion 60-n moves across the magnetic field Bn. As can be seen from the above examples, a preferred embodiment is one in which the detected portion 60-n moves relative to the drive surface Fa across the magnetic field Bn across the drive region Qn and the drive region Q-n+1. The drive coil La-n (detected portion 60-n) moves together with the key 22-n in a direction intersecting the X-axis. The X-axis direction is an example of a "first direction," and the Y-axis or Z-axis direction is an example of a "second direction."

[0084] (3) In the first embodiment, the odd-numbered drive coils La-n1 and the even-numbered drive coils Lb-n2 overlap each other in a plan view, but a configuration in which the drive coils La-n1 and La-n1 do not overlap each other is also possible. Furthermore, in a configuration in which the drive coils La-n1 and La-n1 do not overlap each other, both the drive coils La-n1 and La-n1 may be formed on one of the drive surface Fa and the installation surface Fb of the base material 51.

[0085] (4) In the above-described embodiments, the position P of the key 22-n of the keyboard instrument 100 is identified. However, the movable member whose position P is detected by the detection system 25 is not limited to the key 22-n. Specific examples of the movable member are described below.

[0086] [Aspect A] FIG. 25 is a schematic diagram of a configuration in which a detection system 25 is applied to a string-striking mechanism 91 of a keyboard instrument 100. The string-striking mechanism 91 is an action mechanism that strikes strings (not shown) in conjunction with the movement of each key 22-n of the keyboard 21, similar to that of an acoustic piano. Specifically, the string-striking mechanism 91 includes, for each key 22-n, a hammer 911 that can strike the strings by rotating, and a transmission mechanism 912 (e.g., a wippen, jack, or repetition lever) that rotates the hammer 911 in conjunction with the movement of the key 22-n. In the above configuration, the detection system 25 detects the position of the hammer 911. Specifically, the detection target 60-n is installed on the hammer 911 (e.g., a hammer shank). On the other hand, the signal generating unit 27 is installed on a support member 913. The support member 913 is, for example, a structure that supports the string-striking mechanism 91. The detected part 60-n may be provided on a member other than the hammer 911 in the string-striking mechanism 91.

[0087] [Aspect B] FIG. 26 is a schematic diagram of a configuration in which the detection system 25 is applied to a pedal mechanism 92 of a keyboard instrument 100. The pedal mechanism 92 includes a pedal 921 operated by the user's foot, a support member 922 that supports the pedal 921, and an elastic body 923 that urges the pedal 921 upward in the vertical direction. In the above configuration, the detection system 25 detects the position of the pedal 921. Specifically, the detected portion 60-n is installed on the bottom surface of the pedal 921. Meanwhile, the signal generating unit 27 is installed on the support member 922 so as to face the detected portion 60-n. Note that the instrument in which the pedal mechanism 92 is used is not limited to the keyboard instrument 100. A pedal mechanism 92 with a similar configuration can also be used in any other instrument, such as a percussion instrument.

[0088] Although Fig. 26 illustrates the pedal mechanism 92 of a keyboard instrument 100, a pedal mechanism used in an electric musical instrument such as an electric string instrument (for example, an electric guitar) also employs a configuration similar to that shown in Fig. 26. The pedal mechanism used in an electric musical instrument is an effect pedal operated by the user to adjust various sound effects such as distortion or compressor.

[0089] Furthermore, while the above-described embodiments have been described as examples of configurations for detecting each key 22-n of the keyboard instrument 100, the objects to be detected by the detection system 25 are not limited to these examples. For example, the detection system 25 may detect controls operated by a user when playing a wind instrument such as a woodwind instrument (e.g., a clarinet or saxophone) or a brass instrument (e.g., a trumpet or trombone).

[0090] As can be understood from the above examples, the objects of detection by the detection system 25 are generally expressed as movable parts that move in response to performance manipulations. Movable parts include performance controls such as the keys 22-n or pedals 921 that are directly operated by the user, as well as structures such as the hammer 911 that move in conjunction with manipulations of the performance controls. However, the movable parts in this disclosure are not limited to parts that move in response to performance manipulations. In other words, movable parts are generally expressed as parts that can move regardless of the trigger that causes the movement.

[0091] (5) In the above-described embodiments, the keyboard instrument 100 is illustrated as having a sound source circuit 34. However, in a configuration in which the keyboard instrument 100 has a sound-producing mechanism such as a string-striking mechanism 91, the sound source circuit 34 may be omitted. The detection system 25 is used to record the performance of the keyboard instrument 100. As can be understood from the above explanation, the musical instrument according to the present disclosure includes not only an electronic musical instrument having a sound source circuit 34, but also an acoustic musical instrument having a sound-producing mechanism.

[0092] The present disclosure is also specified as an apparatus (operation device) that controls musical tones by outputting operation signals to a sound source circuit 34 or a sound generation mechanism in response to a performance operation. In addition to musical instruments (keyboard instruments 100) equipped with a sound source circuit 34 or a sound generation mechanism as exemplified in the above embodiments, the concept of an operation device also encompasses devices that do not have a sound source circuit 34 or a sound generation mechanism (for example, a MIDI controller or the pedal mechanism 92 described above). In other words, the instrument playing apparatus in the present disclosure is comprehensively expressed as a device that a performer (operator) operates to perform a performance.

[0093] (6) As described above, the functions of the control system 30 according to each of the above embodiments are realized through cooperation between one or more processors constituting the control device 31 and a program stored in the storage device 32. The programs exemplified above can be provided in a form stored on a computer-readable recording medium and installed on a computer. The recording medium is, for example, a non-transitory recording medium, such as an optical recording medium (optical disk) such as a CD-ROM, but also includes any known type of recording medium, such as a semiconductor recording medium or a magnetic recording medium. Note that a non-transitory recording medium includes any recording medium other than a transitory, propagating signal, and does not exclude volatile recording media. Furthermore, in a configuration in which a distribution device distributes a program via a communication network, the recording medium storing the program in the distribution device corresponds to the non-transitory recording medium described above.

[0094] E: Notes From the above-described exemplary embodiments, the following configurations can be understood, for example.

[0095] A detection system according to one aspect (aspect 1) of the present disclosure comprises a signal generating unit including a drive surface in which a first drive region, a second drive region, and a third drive region are arranged in order in a first direction; a first detection coil mounted on a first movable member with its winding axis aligned with the first direction and moving together with the first movable member in a second direction intersecting the first direction between the first drive region and the second drive region in a planar view; and a second detection coil mounted on a second movable member with its winding axis aligned with the first direction and moving together with the second movable member in the second direction between the second drive region and the third drive region in a planar view; wherein the signal generating unit generates a magnetic field across the first drive region and the second drive region during a first drive period to generate a first detection signal corresponding to the distance between the first detection coil and the drive surface, and generates a magnetic field across the second drive region and the third drive region during a second drive period separate from the first drive period to generate a second detection signal corresponding to the distance between the second detection coil and the drive surface.

[0096] In the above-described embodiment, the detection coil moves across the magnetic field between two adjacent drive regions. Therefore, restrictions on the direction of movement of the detection coil relative to the drive coil can be relaxed compared to, for example, a configuration in which the winding axis of the detection coil is perpendicular to the drive surface. Specifically, the direction of movement of the detection coil relative to the drive surface can be set to any direction within the plane between the two adjacent drive regions. For example, the detection coil may move in a direction intersecting (e.g., perpendicular to) the drive surface, or in a direction parallel to the drive surface.

[0097] The direction of the magnetic field extending between the first drive region and the second drive region is arbitrary. That is, in the first drive period, a magnetic field may be generated from the first drive region to the second drive region, or a magnetic field may be generated from the second drive region to the first drive region. The direction of the magnetic field extending between the second drive region and the third drive region is also arbitrary. That is, in the second drive period, a magnetic field may be generated from the second drive region to the third drive region, or a magnetic field may be generated from the third drive region to the second drive region. It does not matter whether the direction of the magnetic field in the first drive period is the same as the direction of the magnetic field in the second drive period.

[0098] In a specific example (Aspect 2) of Aspect 1, the signal generating unit includes a first drive coil that generates the first detection signal from a first drive signal and a second drive coil that generates the second detection signal from a second drive signal. The first drive coil includes a first portion located in the first drive region and through which a current flows in a first current direction, and a second portion located in the second drive region and through which a current flows in a second current direction opposite to the first current direction. The second drive coil includes a third portion located in the second drive region and through which a current flows in a third current direction, and a fourth portion located in the third drive region and through which a current flows in a fourth current direction opposite to the third current direction. According to the above aspect, the position of each movable member can be detected with high accuracy using a simple configuration that selectively supplies drive signals to each of the multiple drive coils. The third current direction is, for example, the same direction as one of the first and second current directions, and the fourth current direction is, for example, the same direction as the other of the first and second current directions.

[0099] In a specific example (Aspect 3) of Aspect 2, the second portion and the third portion overlap each other in a planar view. In the above aspect, since the second portion and the third portion overlap each other in a planar view, it is easier to reduce the size of the signal generating section (driving surface) compared to an aspect in which the second portion and the third portion do not overlap each other.

[0100] "Planar view" means viewing from a direction perpendicular to the drive surface. Also, "the second portion and the third portion overlap each other in a planar view" includes both partial overlap and total overlap. That is, part or all of the second portion and part or all of the third portion overlap each other.

[0101] In a specific example (aspect 4) of aspect 1, the device further includes a drive circuit, and the signal generation unit includes a first drive coil installed in the first drive area, a second drive coil installed in the second drive area, and a third drive coil installed in the third drive area, and the drive circuit electrically connects the first drive coil and the second drive coil so that, during the first drive period, a current flows through the first drive coil in a first current direction and a current flows through the second drive coil in a second current direction opposite to the first current direction, and generates the first detection signal by supplying a first drive signal to the first drive coil and the second drive coil, and electrically connects the second drive coil and the third drive coil so that, during the second drive period, a current flows through the second drive coil in a third current direction and a current flows through the third drive coil in a fourth current direction opposite to the third current direction, and generates the second detection signal by supplying a second drive signal to the second drive coil and the third drive coil. In the above-described embodiment, the second drive coil is used to detect the position of the first movable member during the first drive period and the position of the second movable member during the second drive period, which reduces the number of drive coils required to detect the position of each movable member compared to an embodiment in which separate drive coils are used to detect the position of each movable member.

[0102] A musical instrument according to one aspect (aspect 5) of the present disclosure includes a first movable member and a second movable member that move in response to a performance operation by a user; a signal generating unit including a drive surface on which a first drive region, a second drive region, and a third drive region are arranged in order in a first direction; a first detection coil that is mounted on the first movable member with its winding axis along the first direction and that moves together with the first movable member in a second direction intersecting the first direction between the first drive region and the second drive region in a plan view; and a second detection coil that is mounted on the second movable member with its winding axis along the first direction and that moves together with the first movable member in a second direction intersecting the first direction in a plan view. The drive device further includes a second detection coil that moves in the second direction together with the second movable member between the second drive region and the third drive region, and the signal generating unit generates a magnetic field across the first drive region and the second drive region during a first drive period to generate a first detection signal corresponding to the distance between the first detection coil and the drive surface, and generates a magnetic field across the second drive region and the third drive region during a second drive period separate from the first drive period to generate a second detection signal corresponding to the distance between the second detection coil and the drive surface. [Explanation of symbols]

[0103] 100...keyboard instrument, 20...keyboard unit, 21...keyboard, 22-n...key, 23...balance pin, 24...support, 25...detection system, 27...signal generating unit, 30...control system, 31...control device, 32...memory device, 33...A / D converter, 34...sound source circuit, 40...sound emission system, 50-n...magnetic field generating unit, 51...substrate, 60-n...detected unit, 61...substrate, 70...drive circuit, 71...supply circuit, 72...output circuit

Claims

1. a signal generating unit including a driving surface on which a first driving region, a second driving region, and a third driving region are arranged in order in a first direction; a first detection coil that is installed on a first movable member with a winding axis aligned along the first direction and that moves together with the first movable member in a second direction intersecting the first direction between the first driving region and the second driving region in a plan view; a second detection coil that is installed on a second movable member with a winding axis aligned along the first direction and that moves together with the second movable member in the second direction between the second driving region and the third driving region in a plan view; The signal generation unit during a first driving period, a magnetic field is generated across the first driving region and the second driving region, thereby generating a first detection signal according to a distance between the first detection coil and the driving surface; In a second driving period separate from the first driving period, a magnetic field is generated across the second driving region and the third driving region, thereby generating a second detection signal according to the distance between the second detection coil and the driving surface. Detection system.

2. The signal generation unit a first drive coil that generates the first detection signal from a first drive signal; a second drive coil that generates the second detection signal from a second drive signal; The first drive coil a first portion disposed within the first driving region and through which a current flows in a first current direction; a second portion disposed within the second driving region, through which a current flows in a second current direction opposite to the first current direction; The second drive coil a third portion disposed within the second driving region, through which a current flows in a third current direction; a fourth portion disposed within the third driving region, through which a current flows in a fourth current direction opposite to the third current direction; The detection system of claim 1 .

3. The second portion and the third portion overlap each other in a plan view. The detection system of claim 2.

4. further comprising a drive circuit; The signal generation unit a first drive coil disposed within the first drive region; a second drive coil disposed within the second drive region; a third drive coil disposed within the third drive region; The drive circuit In the first driving period, electrically connecting the first drive coil and the second drive coil so that a current flows through the first drive coil in a first current direction and a current flows through the second drive coil in a second current direction opposite to the first current direction, and supplying a first drive signal to the first drive coil and the second drive coil to generate the first detection signal; In the second driving period, The second drive coil and the third drive coil are electrically connected so that a current flows through the second drive coil in a third current direction and a current flows through the third drive coil in a fourth current direction opposite to the third current direction, and a second drive signal is supplied to the second drive coil and the third drive coil to generate the second detection signal. The detection system of claim 1 .

5. a first movable member and a second movable member that move in response to a performance operation by a user; a signal generating unit including a driving surface on which a first driving region, a second driving region, and a third driving region are arranged in order in a first direction; a first detection coil that is installed on the first movable member with its winding axis aligned along the first direction and that moves together with the first movable member in a second direction intersecting the first direction between the first driving region and the second driving region in a plan view; a second detection coil that is installed on the second movable member with a winding axis aligned along the first direction and that moves together with the second movable member in the second direction between the second driving region and the third driving region in a plan view; The signal generation unit during a first driving period, a magnetic field is generated across the first driving region and the second driving region, thereby generating a first detection signal according to a distance between the first detection coil and the driving surface; In a second driving period separate from the first driving period, a magnetic field is generated across the second driving region and the third driving region, thereby generating a second detection signal according to the distance between the second detection coil and the driving surface. musical instrument.

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