Performance operation device, keyboard mechanism, and pedal mechanism

Abstract

To reduce unnecessary radiation noise due to a detection signal.SOLUTION: A musical instrument includes: a movable member which is displaced in accordance with performance operation; a fixing member which is not displaced according to the performance operation; a circuit to be detected, which is installed in the movable member and has a magnetic material or a conductor; and a detection circuit which has a coil arranged in the fixing member and outputs a detection signal having an amplitude corresponding to a distance between the circuit to be detected and the coil. The distance in a first state in which a force by the performance operation does not act on the movable member is shorter than the distance in a second state in which the force acts on the movable member.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a performance operation device, a keyboard mechanism, and a pedal mechanism. [Background technology]

[0002] For example, various techniques have been proposed for detecting the displacement of a movable member, such as a key in a keyboard instrument. Patent Document 1 discloses a configuration for detecting the position of a movable member by using an excitation coil and a position detection coil installed on a fixed member, and an excited coil installed on a movable member that moves relative to the fixed member. In this technique, a reference signal is supplied to the excitation coil, and the position of the movable member is detected according to the amplitude of the detection signal output from the position detection coil. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2021-508399 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional technology, unwanted radiation noise caused by the detection signal is a problem. The present disclosure aims to solve the problem of reducing unwanted radiation noise caused by the detection signal. [Means for solving the problem]

[0005] In order to solve the above problems, one embodiment of the musical instrument disclosed herein comprises a fixed member, a movable member that is displaced relative to the fixed member from a first state in an initial position to a second state in response to the playing action of the instrument, a detectable circuit that is installed on the movable member and has a magnetic material or a conductor, and a detection circuit that has a coil arranged on the fixed member and outputs a detection signal whose voltage is proportional to the distance between the detectable circuit and the coil, wherein the distance between the detectable circuit and the coil in the first state is shorter than the distance between the detectable circuit and the coil in the second state. [Brief explanation of the drawings]

[0006] [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 block diagram illustrating the configuration of a keyboard instrument. [Figure 3] FIG. 2 is a circuit diagram of a detection circuit and a detected circuit. [Figure 4] FIG. 2 is a block diagram illustrating the configuration of a drive circuit. [Figure 5] FIG. 2 is a plan view of a signal conversion unit. [Figure 6] FIG. 6 is a cross-sectional view taken along line a in FIG. 5. [Figure 7] FIG. 3 is an explanatory diagram of a magnetic field generated in a signal conversion unit. [Figure 8] FIG. 2 is a circuit diagram illustrating a specific configuration of a resonant circuit in a circuit to be detected. [Figure 9] FIG. 2 is a plan view of the circuit to be detected. [Figure 10] FIG. 10 is a cross-sectional view taken along the line bb in FIG. 9. [Figure 11A] 10 is an explanatory diagram for explaining the amount of deviation Δr between the central axis C1 of the coil La and the central axis C2 of the coil Lb in a plan view from the normal direction of the coil La. FIG. [Figure 11B] 10 is a graph showing characteristics N0, N1, and N2 that indicate the relationship between distance D and voltage E. [Figure 12] 10 is a graph showing normalized characteristics N. [Figure 13]FIG. 2 is a functional block diagram showing the functions of a control device 31. [Figure 14] 1 is a graph showing the relationship between a voltage E and a normalized voltage En. [Figure 15] 10 is a flowchart showing the operation of the control device 31 in a calibration mode. [Figure 16] 10 is a flowchart showing the operation of the control device 31 in a performance mode. [Figure 17] 10 is a graph showing the relationship between the amount of deviation Δr and the voltage E when the distance D between the coils La and Lb is 1 mm. [Figure 18] 1 is a schematic diagram of a configuration in which a detection system 20 is applied to a string striking mechanism 2A of a keyboard instrument 100. FIG. [Figure 19] 1 is a schematic diagram of a configuration in which a detection system 20 is applied to a pedal mechanism 3A of a keyboard instrument 100. FIG. [Figure 20] 1 is a schematic diagram of a configuration in which a detection system 20 is applied to a keyboard mechanism 4A of a keyboard instrument 100. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0007] 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 includes a keyboard 10, a detection system 20, an information processing device 30, and a sound emission device 40. The keyboard instrument 100 is an example of a musical instrument. The keyboard 10 is composed of K keys 12, including white keys and black keys, where K is an integer equal to or greater than 2. For example, K is "88."

[0008] The position of each of the K keys 12 is displaced within a movable range. Each of the K keys 12 is an example of a movable member that is displaced in response to the playing action of the user. The detection system 20 detects the position of each key 12. The information processing device 30 generates an audio signal V in accordance with the detection result by the detection system 20. The audio signal V is a signal representing a musical tone of a pitch corresponding to the key 12 operated by the user. The sound emitting device 40 emits the sound represented by the audio signal V. For example, a speaker or headphones may be used as the sound emitting device 40.

[0009] FIG. 2 is a block diagram illustrating the specific configuration of a keyboard instrument 100, focusing on one key 12 on the keyboard 10. Each key 12 on the keyboard 10 is supported by a support member 14, with a fulcrum (balance pin) 13 as a fulcrum. The support member 14 is a structural body (frame) that supports each element of the keyboard instrument 100. The support member 14 is an example of a fixed member that does not displace in response to a performance action. An end 121 of each key 12 is displaced vertically when the user presses or releases the key. In the following explanation, the position of the end 121 of the key 12 is referred to as the position Z of the key 12. The state in which no force due to a performance action or static load for calibration acts on the key 12 is referred to as the first state, and the state in which a force due to a performance action acts on the key 12 is referred to as the second state. The position Z of the key 12 in the first state is referred to as the rest position Zr. In the second state, the position Z of the key 12 when the key 12 is pressed down to the fullest extent is referred to as the end position Ze. The movable range of each key 12 is from the rest position Zr to the end position Ze. The first state refers to the initial position of the key 12. The first state corresponds to a state in which the key 12 is not displaced (non-displaced state), and the second state corresponds to a state in which the key 12 is displaced (displaced state).

[0010] The detection system 20 generates an amplitude signal A having a level corresponding to the vertical position Z of each of the K keys 12. The position Z is the amount of displacement of the end 121 relative to the position of the end 121 in a first state in which no load is applied to the key 12 (rest position Zr).

[0011] The detection system 20 includes K detection circuits 21, K detected circuits 22, a drive circuit 23, and an amplitude detection circuit 24. The K detection circuits 21 correspond one-to-one to the K keys 12. The K detected circuits 22 correspond one-to-one to the K keys 12. That is, a pair of a detection circuit 21 and a detected circuit 22 is installed for each key 12. Each detection circuit 21 is installed on a support member 14. The detected circuit 22 corresponding to each key 12 is installed on that key 12. Specifically, the detected circuit 22 is installed on the bottom surface 122 of the key 12 (hereinafter referred to as the "installation surface"). The drive circuit 23 and amplitude detection circuit 24 are installed in common to the K keys 12.

[0012] The detection circuit 21 includes a coil La. The detected circuit 22 includes a coil Lb. The coils La and Lb face each other with a gap in the vertical direction. The distance between the detection circuit 21 and the detected circuit 22 (the distance between the coils La and Lb) changes depending on the position Z. The amplitude detection circuit 24 generates an amplitude signal A with a level corresponding to the distance between the coils La and Lb.

[0013] 3 is a circuit diagram illustrating the electrical configuration of the detection circuit 21 and the detected circuit 22 corresponding to any one key 12. The detection circuit 21 includes a resonant circuit 211. The resonant circuit 211 includes an input terminal T1, an output terminal T2, a resistive element R, a coil La, 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 coil La. The other end of the coil La 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).

[0014] The detected circuit 22 includes a resonant circuit 221. The resonant circuit 221 includes a coil Lb and a capacitive element Cb. Specifically, one end of the coil Lb and one end of the capacitive element Cb are connected to each other, and the other end of the coil Lb and the other end of the capacitive element Cb are connected to each other. The resonant frequency of the resonant circuit 211 and the resonant frequency of the resonant circuit 221 are set to the same frequency. However, the resonant frequency of the resonant circuit 211 and the resonant frequency of the resonant circuit 221 may be different. For example, the resonant frequency of the resonant circuit 211 is set to a frequency obtained by multiplying the resonant frequency of the resonant circuit 221 by a predetermined constant.

[0015] FIG. 4 is a block diagram illustrating a specific configuration of the drive circuit 23. The drive circuit 23 includes a supply circuit 231 and an output circuit 232. The supply circuit 231 supplies a reference signal W to the input terminal T1 of each of the K detection circuits 21. For example, the supply circuit 231 is a demultiplexer that supplies the reference signal W to each of the K detection circuits 21 in a time-division manner. The reference signal W is a voltage signal whose level fluctuates periodically. For example, a periodic signal with an arbitrary waveform, such as a sine wave, a rectangular wave, or a sawtooth wave, is used as the reference signal W. One period of the reference signal W is sufficiently shorter than the duration of the period during which the reference signal W is supplied to one detection circuit 21. The frequency of the reference signal W is set to a frequency approximately equal to the resonant frequency of the resonant circuits 211 and 221.

[0016] The reference signal W is supplied to the coil La via the input terminal T1 and the resistor R. The reference signal W generates a magnetic field in the coil La. The magnetic field generated in the coil La generates an induced current in the coil Lb of the detected circuit 22 due to electromagnetic induction. That is, a magnetic field is generated in the coil La in a direction that offsets the change in the magnetic field in the coil Lb. In the following description, the distance between the coils La and Lb is referred to as the distance D. The magnetic field generated in the coil La changes depending on the distance D. Therefore, the amplitude δ of the detection signal s changes depending on the distance D. The detection circuit 21 outputs the detection signal s having an amplitude δ corresponding to the distance D via the output terminal T2. The longer the distance D, the larger the amplitude δ of the detection signal s becomes, and the shorter the distance D, the smaller the amplitude δ becomes. This is because the shorter the distance D, the more current flows through the coil La to cancel out the magnetic field generated in the coil Lb. In this embodiment, when the key 12 is in the rest position Zr, the coils La and Lb are closest to each other, and the distance D is smallest. Therefore, when the key 12 is in the rest position Zr, the amplitude δ of the detection signal s is minimum. In other words, the detecting circuit 21 and the detected circuit 22 are arranged so that the amplitude δ of the detection signal s is minimum in the first state.

[0017] The distance D is minimized at the rest position Zr for the following reasons. The first reason is to reduce unwanted radiation noise caused by the amplitude δ of the detection signal s. The keyboard instrument 100 in this example has 88 keys 12. During performance, for example, 10 keys 12 may be pressed, but even in that case, 78 keys 12 are not pressed and are in the first state. Therefore, compared to when the distance D is minimized at the end position Ze, when the distance D is minimized at the rest position Zr, unwanted radiation noise from the keyboard instrument 100 can be reduced more effectively.

[0018] The second reason is that calibration, which will be described later, can be performed in the first state in which the key 12 is located at the rest position Zr. The amplitude δ of the detection signal s fluctuates due to factors such as misalignment of the mounting positions of the coils La and Lb. As will be described later, in this embodiment, calibration is performed to absorb the fluctuations in the amplitude δ. It is preferable to perform calibration when the distance D is at its smallest. When the distance D is at its smallest at the rest position Zr, this has the advantage that calibration can be performed immediately after the keyboard instrument 100 is powered on.

[0019] The output circuit 232 in Figure 4 is a multiplexer that generates a detection signal S by arranging the detection signals s output sequentially from each of the multiple detection circuits 21 on a time axis. The output circuit 232 generates the detection signal S by time-division multiplexing the K detection signals s. That is, the detection signal S is a voltage signal having an amplitude δ that corresponds to the distance between the coil La and the coil Lb in each key 12. As mentioned above, the distance between the coil La and the coil Lb correlates with the position Z of each key 12, so the detection signal S can be expressed as a signal that corresponds to the position Z of each of the K keys 12.

[0020] The amplitude detection circuit 24 generates an amplitude signal A by rectifying the detection signal S and then smoothing it. The rectification may be either half-wave rectification or full-wave rectification. The amplitude signal A has a voltage E corresponding to the amplitude δ of the detection signal S. Therefore, the amplitude signal A is a signal obtained by time-division multiplexing signals indicating the voltage E corresponding to the amplitude δ of each detection signal s. The amplitude detection circuit 24 outputs the amplitude signal A to the information processing device 30. Note that the detection system 20 may also output the detection signal S to the information processing device 30. In this case, the information processing device 30 may detect the amplitude δ of each detection signal s based on the detection signal S.

[0021] FIG. 5 is a plan view illustrating a specific configuration of a detection circuit 21 corresponding to one key 12. FIG. 5 shows a plan view of the detection circuit 21 as seen from the side of the detected circuit 22 (vertically above). FIG. 6 is a cross-sectional view taken along line a in FIG. 5. The vertical direction in FIG. 5 corresponds to the direction in which the K keys 12 are arranged. The horizontal direction in FIG. 5 corresponds to the longitudinal direction of the keys 12.

[0022] The detection circuit 21 is a circuit board 50 including a substrate 51 on which a resonant circuit 211 is mounted. The substrate 51 is an insulating plate-like member including a surface 511 and a surface 512. The surface 511 is the surface opposite to the surface 512. The surface 511 is the upper surface of the substrate 51 that faces the detected circuit 22. The surface 512 is the lower surface of the substrate 51 that faces the support member 14.

[0023] On the substrate 51, wiring patterns 52-1 and 52-2 for configuring the resonant circuit 211 are formed. The wiring pattern 52-1 is formed on the surface 511, and the wiring pattern 52-2 is formed on the surface 512. Each of the wiring patterns 52-1 and 52-2 is a conductive film formed in a predetermined planar shape. Specifically, the wiring pattern 52-1 is formed by patterning a conductive film that covers the entire surface 511. Similarly, the wiring pattern 52-2 is formed by patterning a conductive film that covers the entire surface 512.

[0024] The wiring pattern 52-1 includes a first coil portion La1, a second coil portion La2, an input terminal T1, an output terminal T2, and a ground terminal Tg. As described with reference to Fig. 3, a reference signal W is supplied to the input terminal T1, and an amplitude signal A is output from the output terminal T2. The ground terminal Tg is grounded.

[0025] Each of the first coil portion La1 and the second coil portion La2 is formed in a rectangular spiral shape. The spiral direction of the first coil portion La1 is the same as that of the second coil portion La2. For example, the first coil portion La1 and the second coil portion La2 form a counterclockwise spiral from the center to the outside. The first coil portion La1 and the second coil portion La2 are adjacent to each other. Specifically, the first coil portion La1 and the second coil portion La2 are arranged in a direction perpendicular to the direction in which the K keys 12 are arranged (horizontal direction).

[0026] The wiring pattern 52-2 includes a connection portion La3. The center of the first coil portion La1 is electrically connected to one end of the connection portion La3 via a conductive hole H11. The center of the second coil portion La2 is electrically connected to the other end of the connection portion La3 via a conductive hole H12. Each of the conductive holes H11 and H12 is a through-hole that penetrates the substrate 51. As described above, the first coil portion La1 and the second coil portion La2 are electrically connected to each other via the connection portion La3. The first coil portion La1, the second coil portion La2, and the connection portion La3 form the coil La of FIG. 3.

[0027] A resistive element R and capacitive elements Ca1 and Ca2 are mounted on a surface 511 of the substrate 51. The resistive element R is mounted on the substrate 51 as an electronic component (chip resistor). Similarly, the capacitive elements Ca1 and Ca2 are mounted on the substrate 51 as electronic components (chip capacitors).

[0028] When current is supplied, a magnetic field is generated in each of the first coil section La1 and the second coil section La2. As can be seen from FIG. 5, the direction of current flowing through the first coil section La1 is opposite to the direction of current flowing through the second coil section La2. Therefore, as illustrated in FIG. 7, magnetic fields are generated in opposite directions in the first coil section La1 and the second coil section La2. That is, when a magnetic field in a first direction is generated in the first coil section La1, a magnetic field in a second direction opposite to the first direction is generated in the second coil section La2. With the above configuration, a magnetic field is formed from one of the first coil section La1 and the second coil section La2 to the other, thereby reducing the diffusion of the magnetic field between adjacent keys 12. That is, magnetic field interference between two adjacent coils Lb is reduced. Therefore, a detection signal s that accurately reflects the position Z of each of the K keys 12 can be generated.

[0029] Fig. 8 is a circuit diagram illustrating a specific configuration of the resonant circuit 221 in the detected circuit 22. The coil Lb illustrated in Fig. 3 is actually composed of a first coil portion Lb1 and a second coil portion Lb2. The first coil portion Lb1 and the second coil portion Lb2 are connected in series between a wiring 651 and a wiring 652. Each of the first coil portion Lb1 and the second coil portion Lb2 includes four portions 64-1 to 64-4 connected in series with each other.

[0030] 3 is actually composed of four capacitive elements Cb1 to Cb4. The four capacitive elements Cb1 to Cb4 are connected in parallel between wiring 651 and wiring 652. Each of the four capacitive elements Cb1 to Cb4 is composed of three capacitive units 66-1 to 66-3 connected in parallel to each other. The capacitive unit 66-1 includes an electrode 67-1 and an electrode 67-2. The capacitive unit 66-2 includes an electrode 67-2 and an electrode 67-3. The capacitive unit 66-3 includes an electrode 67-3 and an electrode 67-4.

[0031] FIG. 9 is a plan view illustrating a specific configuration of the detection target circuit 22. FIG. 9 shows a plan view of the detection target circuit 22 as seen from the detection circuit 21 side (vertically downward). FIG. 10 is a cross-sectional view taken along line bb in FIG. 9. In the following description, we will assume that the X-axis and Y-axis are orthogonal to each other. The XY plane is a plane parallel to the installation surface 122 of the keys 12. The K keys 12 are arranged along the X-axis, and each key 12 is elongated along the Y-axis. Observation along a direction perpendicular to the XY plane will be referred to as "planar view" below.

[0032] The detected circuit 22 is a circuit board 60 including a substrate 61 on which a resonant circuit 221 is installed. The substrate 61 is an insulating plate-like member including a surface 611 and a surface 612. The surface 611 is the surface opposite to the surface 612. Specifically, the surface 611 is the surface of the substrate 61 that faces the detection circuit 21. The surface 612 is the surface of the substrate 61 that faces the installation surface 122 of the key 12. The substrate 61 of the first embodiment is formed in a rectangular shape that is elongated in the Y-axis direction.

[0033] The substrate 61 includes multiple regions (Q11, Q12, Q13, Q21, Q22, and Q23) arranged along the Y axis. Regions Q11 and Q21 are regions of the substrate 61 near the center in the Y axis direction. Region Q11 is located in the negative direction of the Y axis relative to the midpoint of the substrate 61 in the Y axis direction, and region Q21 is located in the positive direction of the Y axis relative to the midpoint. Region Q13 is a region including an end portion 614 of the substrate 61 located in the negative direction of the Y axis. Region Q12 is a region between regions Q11 and Q13. Similarly, region Q23 is a region including an end portion 615 of the substrate 61 located in the positive direction of the Y axis, and region Q22 is a region between regions Q21 and Q23.

[0034] The first coil portion Lb1 is formed in region Q11. The capacitive elements Cb1 and Cb2 are formed in region Q13. The capacitive elements Cb1 and Cb2 are arranged in region Q13 at intervals in the X direction in plan view. As can be understood from the above explanation, the capacitive elements Cb1 and Cb2 are formed between the first coil portion Lb1 and the end 614 of the substrate 61 in plan view. In other words, the capacitive elements Cb1 and Cb2 are formed at a position spaced apart from the first coil portion Lb1 in the negative direction of the Y axis by an interval corresponding to region Q12.

[0035] In a configuration in which the capacitance elements Cb1 and Cb2 are close to the first coil portion Lb1, the magnetic field generated in the first coil portion Lb1 is affected by the capacitance elements Cb1 or Cb2. According to the configuration of the first embodiment in which the region Q12 is formed between the capacitance elements Cb1 and Cb2 and the first coil portion Lb1, it is easy to ensure the distance between the capacitance elements Cb1 and Cb2 and the first coil portion Lb1. Therefore, the influence of the capacitance elements Cb1 and Cb2 on the magnetic field generated in the first coil portion Lb1 can be reduced.

[0036] The second coil portion Lb2 is formed in region Q21. The capacitive elements Cb3 and Cb4 are formed in region Q23. The capacitive elements Cb3 and Cb4 are arranged in region Q23 at intervals in the X direction in plan view. As can be understood from the above explanation, the capacitive elements Cb3 and Cb4 are formed at positions spaced apart from the second coil portion Lb2 in the positive direction of the Y axis by an interval corresponding to region Q12. This makes it easy to ensure the distance between the capacitive elements Cb3 and Cb4 and the second coil portion Lb2.

[0037] As can be seen from the above example, in plan view, the coil Lb (first coil portion Lb1 and second coil portion Lb2) is located between the set of capacitance elements Cb1 and Cb2 and the set of capacitance elements Cb3 and Cb4. The above configuration has the advantage that, compared to a configuration in which the capacitance element Cb is formed between the first coil portion Lb1 and the second coil portion Lb2, it is easier to ensure the capacitance of the capacitance element Cb while reducing the effect of the capacitance element Cb (Cb1 to Cb4) on the magnetic field generated in the coil Lb.

[0038] Returning to Figure 2 for further explanation, the information processing device 30 generates position data indicating the position Z of each key 12 by analyzing the amplitude signal A supplied from the drive circuit 23. The information processing device 30 is implemented as a computer system comprising a control device 31, a storage device 32, an A / D converter 33, and a tone generator circuit 34. The information processing device 30 may be implemented as a single device, or may be implemented as multiple devices configured separately from each other.

[0039] 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), an SPU (Sound Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or an ASIC (Application Specific Integrated Circuit).

[0040] The storage device 32 is one or more memories that store a program 321 executed by the control device 31 and correspondence data 322. The correspondence data 322 is data that indicates the correspondence between a voltage E corresponding to the amplitude δ of the detection signal s and a position Z. The correspondence data 322 includes calibration data 322a and conversion data 322b. The calibration data 322a is data that is used to generate a normalized voltage En, which will be described later, from the voltage E corresponding to the amplitude δ of the detection signal s. The conversion data 322b is data that indicates the correspondence between the normalized voltage En and a position Z. The storage device 32 also functions as a work area for 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 media. 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.

[0041] The A / D converter 33 converts the amplitude signal A supplied from the drive circuit 23 from analog to digital. The control device 31 generates position data indicating the position Z of each of the K keys 12 by analyzing the amplitude signal A converted by the A / D converter 33. The control device 31 also instructs the sound source circuit 34 to generate musical tones corresponding to the position Z of each key 12. The sound source circuit 34 generates an audio signal V representing the musical tones instructed by the control device 31. Specifically, the audio signal V represents a musical tone of a pitch corresponding to a key 12 whose position Z has changed among multiple pitches. The volume of the audio signal V is controlled, for example, according to the rate at which the position Z changes. The audio signal V is supplied from the sound source circuit 34 to the sound emitting device 40, causing the sound emitting device 40 to emit musical tones corresponding to the user's playing actions (key depression or key release of each key 12). The control device 31 may also implement the function of the sound source circuit 34 by executing a program 321 stored in the storage device 32.

[0042] The relationship between the voltage E of the amplitude signal A and the distance D between the coil La and the coil Lb will be described. FIG. 11A is an explanatory diagram for explaining the amount of deviation Δr between the central axis C1 of the coil La and the central axis C2 of the coil Lb in a plan view. The amount of deviation Δr shown in FIG. 11A is expressed as Δr=(Δx 2 +Δy 2 ) 1 / 2 where Δx is the distance along the X axis between the central axis C1 and the central axis C2, and Δy is the distance along the Y axis between the central axis C1 and the central axis C2.

[0043] FIG. 11B is a graph showing characteristics N0, N1, and N2, which indicate the relationship between distance D and voltage E. Characteristic N0 is a curve showing the relationship between distance D and voltage E when the amount of deviation Δr is zero, i.e., when the central axis C1 of coil La and the central axis C2 of coil Lb are aligned in a planar view. Characteristic N1 is a curve showing the relationship between distance D and voltage E when the amount of deviation Δr=r1. Characteristic N2 is a curve showing the relationship between distance D and voltage E when the amount of deviation Δr=r2, where r2>r1.

[0044] That is, the shorter the offset Δr, the smaller the voltage E when the distance D is zero. This is because the shorter the offset Δr, the greater the extent to which the magnetic field of coil Lb affects the magnetic field of coil La. On the other hand, when the distance D is 10 mm or more, the voltage E is hardly affected by the distance between the central axis C1 and the central axis C2 of coil Lb. This is because when the distance D is 10 mm or more, the magnetic field of coil Lb hardly affects the magnetic field of coil La.

[0045] As described above, the detection circuit 21 having the coil La is mounted on the support member 14, and the detected circuit 22 having the coil lb is mounted on the mounting surface 122 of the key 12. Meanwhile, the movable range of the key 12 is from the rest position Zr to the end position Ze. In this embodiment, when the key 12 is in the rest position Zr, the coils La and Lb are closest to each other. In this case, the distance Dr is 3 mm. Meanwhile, when the key 12 is in the end position Ze, the coils La and Lb are farthest apart. In this case, the distance De is 10 mm.

[0046] However, there is variation in the mounting position of the detection circuit 21 on the support member 14 and the mounting position of the detected circuit 22 on the key 12. As a result, the relationship between distance D and voltage E varies for each key 12, as indicated by characteristics N0, N1, and N2. Furthermore, the resistance value of the resistive element R, the inductance value of the coil La, the capacitance value of the capacitive element Ca1, and the capacitance value of the capacitive element Ca2, all of which constitute the detection circuit 21, vary. The relationship between distance D and voltage E also varies for each key 12 due to variations in the values ​​of these elements, as well as their temperature characteristics and aging.

[0047] In this embodiment, in order to absorb various variations, the multiple characteristics shown in FIG. 11 are normalized to a normalized characteristic N shown in FIG. 12, and the normalized characteristic N is used to find the distance D from the voltage E. The normalized characteristic N shows the relationship between the normalized voltage En obtained by normalizing the voltage E and the distance D. The normalized voltage En is given by equation (1). En = (E - E0) / (Ei - E0)...(1) Here, E0 is the voltage value of the voltage E when the distance D is zero. That is, E0 is the voltage value of the voltage E when the detection circuit 21 and the detected circuit 22 are in contact. Ei is the voltage value of the voltage E when the distance D is infinite. That is, Ei is the value of the voltage E when the detected circuit 22 is not present. The normalized voltage En varies within a range of 0 to 1.

[0048] Incidentally, before the K detection circuits 21 are arranged on the support member 14 and the K keys 12 are installed in the keyboard instrument 100, there are no detection target circuits 22 paired with the detection circuits 21. Therefore, in this state, the voltage value Ei can be measured. On the other hand, the voltage value E0 cannot be measured unless there are detection target circuits 22 paired with the detection circuits 21. Therefore, the voltage value E0 must be measured after the K keys 12, each with its associated detection target circuit 22, are installed in the keyboard instrument 100. However, because the keys 12 can only be displaced up to the rest position Zr, the voltage value E0 cannot be measured. Therefore, in this embodiment, the voltage value E0 is estimated based on the rest voltage value Er of the voltage E at the rest position Zr, and the normalized voltage En is calculated using the estimated voltage value E0.

[0049] The position Z of the key 12 corresponding to the voltage value E0 is the position Z of the key 12 where the distance D is zero. The position Z of the key 12 where the distance D is zero is an example of a reference position. The position Z of the key 12 where the distance D is zero is an example of a position Z of the key 12 that is closer to the coil La than the rest position Zr where the distance D is smallest within the movable range. The rest position Zr is an example of a predetermined position within the movable range of the key 12 (movable member). Furthermore, the rest position Zr is the position Z of the key 12 where the distance D is smallest within the movable range of the key 12.

[0050] The normalized characteristic N indicates the relationship between the normalized voltage En and the distance D. In the keyboard instrument 100, the normalized voltage En is calculated by normalizing the voltage E, and the distance D is determined based on the calculated normalized voltage En. For this reason, an inverse function of the normalized characteristic N is calculated in advance. The function indicating the normalized characteristic N is given by the following equation (2). On the other hand, the inverse function is given by equation (3). En=F(D)…(2) D=F -1 (En)…(3)

[0051] The conversion data 322b stored in the storage device 32 indicates the inverse function shown in equation (3). Therefore, by referring to the conversion data 322b, the distance D corresponding to the normalized voltage En can be obtained.

[0052] The operating modes of the keyboard instrument 100 are broadly divided into a calibration mode and a performance mode. A setting unit 310, which will be described later, switches the operating mode of the keyboard instrument 100 between the performance mode and the calibration mode. In the calibration mode, the control device 31 generates calibration data 322a by executing a calibration process. In the performance mode, the control device 31 also detects an amplitude signal A corresponding to the user's performance action, and generates an audio signal V based on the detected amplitude signal A.

[0053] 13 is a functional block diagram showing the functions of the control device 31. The control device 31 reads a program 321 from the storage device 32 and executes the read program, thereby functioning as a setting unit 310, a calibration unit 311, a generation unit 312, and a sound source control unit 313.

[0054] The setting unit 310 sets the operation mode of the keyboard instrument 100 to a calibration mode or a performance mode. When a predetermined condition is satisfied, the setting unit 310 transitions the operation mode of the keyboard instrument 100 from the calibration mode to the performance mode, or from the performance mode to the calibration mode. For example, when the keyboard instrument 100 is powered on, the setting unit 310 selects the calibration mode, and when a series of calibration processes is completed, the setting unit 310 transitions the operation mode from the calibration mode to the termination mode. Furthermore, the setting unit 310 may transition the operation mode from the performance mode to the calibration mode upon detecting that multiple predetermined keys 12 out of the K keys 12 are pressed simultaneously in the performance mode. For example, the condition for transitioning from the performance mode to the calibration mode may be that the leftmost key 12 and the rightmost key 12 out of the K keys 12 are pressed simultaneously.

[0055] The calibration unit 311 operates in the calibration mode. The calibration unit 311 generates calibration data 322a by analyzing the amplitude signal A and stores the generated calibration data 322a in the storage device 32. The generation unit 312 operates in the performance mode. The generation unit 312 generates position data indicating the position Z of the key 12 based on the voltage E. The generation unit 312 includes a correction unit 312a and a conversion unit 312b. The correction unit 312a corrects the voltage E using the calibration data 322a to generate a normalized voltage En. The conversion unit 312b operates in the performance mode. The conversion unit 312b converts the normalized voltage En into a distance D by referring to the conversion data 322b. The generation unit 312 generates the position data based on the distance D. The sound source control unit 313 generates performance data for controlling the sound source circuit 34 based on the position data.

[0056] As described above, K voltages E, which correspond one-to-one to the K detection circuits 21, are time-division multiplexed in the amplitude signal A. When the key 12 is in the first state, the position Z of the key 12 is the rest position Zr. The voltage E when the key 12 is in the rest position Zr is referred to as the rest voltage value Er. In the first state in which the key 12 is in the rest position Zr, the calibration unit 311 calculates an average rest voltage value Era, which is the average value of the K rest voltage values ​​Er, based on the amplitude signal A. The average rest voltage value Era is given by the following equation (4): Era = (Er1 + Er2 + ... + ErK) / K ... (4) Here, Er1, Er2, . . . ErK are rest voltage values ​​Er that correspond one-to-one to the K keys 12.

[0057] The calibration unit 311 estimates the voltage value E0 based on the average rest voltage value Era. FIG. 14 shows the relationship between the voltage E and the normalized voltage En. The voltage value Enr is the value of the normalized voltage En when the key 12 is located at the rest position Zr. The voltage value Enr is known. The voltage value Ei is also known. Therefore, E0 can be calculated by substituting the average rest voltage value Era into equation (1). Substituting the average rest voltage value Era and the voltage value Enr into equation (1) yields equation (5). Enr = (Era - E0) / (Ei - E0)…(5) Transforming equation (5) yields equation (6). E0 = (Era - Enr * Ei) / (1 - Enr) ... (6) The calibration unit 311 estimates the voltage value E0 using equation (6).

[0058] The reason why the voltage value E0 is estimated using the average rest voltage value Era is as follows. The first reason is that the rest voltage value Er can be measured when the key 12 is located at the rest position Zr. In this embodiment, in the first state in which no force due to playing actions is acting on the key 12, the key 12 is located at the rest position Zr. Therefore, the voltage value E0 can be estimated during the period from when the keyboard instrument 100 is powered on until a predetermined time has elapsed. Since it is highly likely that the user has not started playing in the period immediately after powering on, it is possible to perform calibration without the user being aware that the calibration mode is in effect.

[0059] The second reason is that the rest position Zr is the position of the key 12 in the first state, and therefore has less variation compared to other positions within the movable range.

[0060] The third reason is that the distance Dr at the rest position Zr is 3 mm on average, and the voltage value of the normalized voltage En relative to the distance Dr is Enr. The actual voltage value Enr varies for each key 12. However, when K keys 12 are installed in the keyboard instrument 100, it is not possible to measure the distance Dr for each key 12, and it is known that the average value of the distance Dr is 3 mm. Therefore, there is little need to estimate the voltage value E0 for each key 12. Furthermore, because there is no need to estimate the voltage value E0 for each rest voltage value Er, the processing load on the control device 31 can be reduced.

[0061] The calibration unit 311 generates calibration data 322a using the estimated voltage value E0. The calibration data 322a is data that represents the relationship between the voltage E and the normalized voltage En. The voltage E and the normalized voltage En have a linear relationship as shown in FIG. 8. Therefore, the voltage E and the normalized voltage En have a relationship represented by the following equation (7). En=p*E+q…(7) where p and q are constants. The constant q is expressed by equation (8), and the constant p is expressed by equation (9). p=1 / (Ei-E0)…(8) q=-E0 / (Ei-E0)…(9)

[0062] The calibration unit 311 generates a pair of constants q and p as calibration data 322a based on the estimated voltage value E0 and the voltage value Ei measured in advance. The calibration unit 311 may generate a pair of constants p and q for each detection circuit 21, or may generate a pair of constants p and q common to the K detection circuits 21. When generating a pair of constants p and q for each detection circuit 21, the calibration unit 311 generates the pair of constants p and q for each detection circuit 21 based on the voltage value Ei measured for each detection circuit 21 and the voltage value E0 common to the K detection circuits 21. On the other hand, when generating a pair of constants p and q common to the K detection circuits 21, the calibration unit 311 generates the pair of constants p and q based on the average voltage of the voltage values ​​Ei measured for each detection circuit 21 and the voltage value E0 common to the K detection circuits 21.

[0063] The correction unit 312a uses the calibration data 322a to correct the voltage E to generate a normalized voltage En. The conversion unit 312b uses the conversion data 322b to generate a distance D from the normalized voltage En. The generation unit 312 generates position data indicating the position of the key 12 from the generated distance D.

[0064] Next, the operation of the control device 31 will be explained separately for the calibration mode and the performance mode. FIG. 15 is a flowchart showing the operation of the control device 31 in the calibration mode. The operation of FIG. 15 is executed during the period from when the keyboard instrument 100 is powered on until a predetermined time has elapsed. The predetermined time is preferably between 0.1 seconds and 3 minutes. In the calibration mode, the control device 31 functions as a calibration unit 311.

[0065] First, the control device 31 sets a variable k to "1" (S11). Next, the control device 31 acquires the rest voltage value Er of the key 12 at the rest position Zr (S12). As described above, the key 12 is located at the rest position Zr in the first state. Therefore, no special work is required to position the key 12 at the rest position Zr. The control device 31 acquires the voltage E of the amplitude signal A corresponding to the kth key 12 as the rest voltage value Er.

[0066] Next, the control device 31 determines whether the variable k is equal to "K" (S13). If the determination result is negative, the control device 31 increments the variable k by "1" (S14) and returns the process to step S12. If the determination result in step S13 is positive, the control device 31 calculates the average rest voltage value Era according to the above-mentioned equation (4) (S15).

[0067] Next, the control device 31 estimates the voltage value E0 based on the average rest voltage value Era, the voltage value Ei, and the voltage value Enr of the normalized voltage En corresponding to the distance Dr (S16). Thereafter, the control device 31 generates calibration data 322a using the voltage value Ei and the estimated voltage value E0, and stores the generated calibration data 322a in the storage device 32 (S17).

[0068] 16 is a flowchart showing the operation of the control device 31 in the performance mode. The operation of FIG. 16 is executed sequentially or in parallel for each of the K keys 12. First, the control device 31 obtains a voltage E corresponding to the amplitude δ of the detection signal s based on the amplitude signal A (S21).

[0069] Next, the control device 31 uses the calibration data 322a to calculate the normalized voltage En from the voltage E (S22). Specifically, the control device 31 calculates the normalized voltage En by substituting the pair of constants p and q indicated by the calibration data 322a and the voltage E into equation (7). In step S22, the control device 31 functions as the correction unit 312a.

[0070] Next, the control device 31 generates a distance D from the normalized voltage En using the conversion data 322b (S23). The conversion data 322b is data that associates the normalized voltage En with the distance D. Specifically, the control device 31 generates the distance D corresponding to the normalized voltage En generated in step S22 by referring to the conversion data 322b. If the generated normalized voltage En is not recorded in the conversion data 322b, the control device 31 may calculate the distance D by interpolation.

[0071] Next, the control device 31 generates position data indicating the position Z of the key 12 from the distance D (S24). Next, the control device 31 generates performance data from the position data (S25). The generated performance data is supplied to the sound source circuit 34. Thereafter, the control device 31 determines whether or not the control device 31 is in performance mode (S26). If the determination result in step S26 is positive, the control device 31 returns the process to step S21. If the determination result in step S26 is negative, the control device 31 ends the performance mode.

[0072] As described above, the keyboard instrument 100 according to the first embodiment includes the keys 12 that move in response to playing movements, the support member 14 that does not move in response to playing movements, the detection circuit 22 that is attached to the keys 12 and has a coil Lb, and the detection circuit 21 that has a coil La attached to the support member 14 and outputs a detection signal s with an amplitude δ that corresponds to the distance D between the detection circuit 22 and the coil La. Here, the distance D in the first state, in which no force due to playing movements acts on the keys 12, is shorter than the distance D in the second state, in which force acts on the keys 12. In other words, the distance D is at its smallest in the first state. The shorter the distance D, the smaller the amplitude δ of the detection signal s. Therefore, when the user is not pressing the keys 12, the amplitude δ of the detection signal s is small. Therefore, in the first state, unwanted radiation noise caused by the amplitude δ of the detection signal s can be reduced.

[0073] The keyboard instrument 100 according to the first embodiment also includes a calibration unit 311 that calibrates correspondence data 322 indicating the correspondence between the voltage E and the position Z of the key 12 based on the voltage E corresponding to the amplitude δ of the detection signal s in the first state, and a generation unit 312 that uses the correspondence data 322 calibrated by the calibration unit 311 to generate position data indicating the position of the key 12 based on the voltage E in the second state. Since the first state is a state in which no force due to a performance action is applied to the key 12, calibration is performed when the key 12 is in the rest position Zr. This allows calibration to be performed even when the user is not playing. For example, the calibration unit 311 may calibrate the correspondence data 322 during a period from when the power is turned on until a predetermined time has elapsed. Since the user is likely not to have started playing during this period, the calibration of the correspondence data 322 can be performed without the user being aware of the calibration. As a result, the accuracy of the position data is improved by calibrating the variation in voltage E due to the mounting positions of the detection circuit 21 and the detected circuit 22. Furthermore, by performing calibration every time the power is turned on, variations in voltage E due to the temperature characteristics and aging of the detection circuit 21 and the detected circuit 22 can be calibrated.

[0074] When the K keys 12 are in the first state, the calibration unit 311 calculates an average rest voltage value Era, which is the average value of the voltages E for the K detection signals s output from the K detection circuits 21, and calibrates the correspondence data 322 based on the calculated average rest voltage value Era. Because there is no need to estimate the voltage value E0 for each rest voltage value Er, the processing load on the control device 31 can be reduced.

[0075] Furthermore, it is easy to position the key 12 at the rest position Zr, where the distance D is the smallest within the movable range, and at the end position Ze, where the distance D is the largest. Furthermore, as shown in Fig. 11B, the sensitivity of the voltage E to the deviation Δr is greater at the rest position Zr than at the end position Ze. Therefore, by calibrating the correspondence data 322 based on the rest voltage value Er, which corresponds to the amplitude of the detection signal s when the key 12 is located at the rest position Zr, the accuracy of the calibration is improved.

[0076] Furthermore, the calibration unit 311 estimates the voltage value E0 corresponding to the position Z of the key 12 where the distance D is zero, based on the rest voltage value Er corresponding to the rest position Zr, and calibrates the correspondence data 322 based on the estimated voltage value E0. The position Z of the key 12 where the distance D is zero (an example of a reference position) is closer to the coil La than the rest position Zr of the key 12 where the distance D is smallest within the movable range. As shown in FIG. 11B, the sensitivity of the voltage E to the deviation Δr is greater when the key 12 is located closer to the coil La than the rest position Zr. Therefore, by calibrating the correspondence data 322 based on the estimated voltage value E0, the accuracy of the calibration is improved.

[0077] B: Second embodiment The keyboard instrument 100 of the first embodiment described above estimated a voltage value E0 common to each detection circuit 21 based on the voltage value Enr of the normalized voltage En corresponding to the rest position Zr and the average rest voltage value Era. In contrast, the keyboard instrument 100 of the second embodiment differs from the keyboard instrument 100 of the first embodiment in that it measures the voltage value Er of the voltage E corresponding to the rest position Zr for each detection circuit 21 and estimates the voltage value E1 of the voltage E when the distance D is 1 mm based on the voltage value Er. The keyboard instrument 100 of the second embodiment is similar to the keyboard instrument 100 of the first embodiment except for the estimation of the voltage value E1 in the calibration unit 311. The keyboard instrument 100 of the second embodiment will be described below, focusing on the differences.

[0078] FIG. 17 is a graph showing the relationship between the displacement Δr and the voltage E when the distance D between coil La and coil Lb is 1 mm. As described with reference to FIG. 11A, the displacement Δr indicates the distance between the central axis C1 of coil La and the central axis C2 of coil Lb in a planar view. As shown in FIG. 17, the voltage E when the distance D is 1 mm depends on the displacement Δr. Therefore, if the displacement Δr can be determined, the voltage E when the distance D is 1 mm can be estimated. In the following description, the voltage value of the voltage E when the distance D is 1 mm will be referred to as "E1."

[0079] Voltage value E1 is close enough to voltage value E0 that it can be approximated. However, voltage value E1 cannot be actually measured because it is the voltage E when distance D is 1 mm. Therefore, control device 31 needs to estimate voltage value E1.

[0080] Next, a method for estimating the voltage value E1 will be described. The voltage value Er at the rest position Zr and the deviation amount Δr have the relationship shown in the following approximate formula (8). Er=h2*Δr 2 +h1*Δr+h0…(8) where h2, h1, and h0 are constants.

[0081] If the voltage value Er can be measured, the deviation Δr can be calculated by substituting the measured voltage value Er into the approximate formula (8). The deviation Δr is given by formula (9). Δr=[-h1+{h1 2 -4(h0-Er)*h2} 1 / 2 ] / (2*h2)…(9) It is also possible to store a lookup table corresponding to the approximate formula (9) in the storage device 32 and generate the deviation amount Δr by referring to the lookup table.

[0082] The voltage value E1 is given by the following approximate formula (10). E1=m4*Δr 4 +m3*Δr 3 +m2*Δr 2 +m1*Δr+m0…(10) where m4, m3, m2, m1, and m0 are constants. The voltage value E1 is estimated as follows. First, the voltage value Er is measured in a first state in which the key 12 is located in the rest position Zr. Second, the deviation Δr is calculated by substituting the voltage value Er into equation (9). Third, the voltage value E1 is estimated by substituting the deviation Δr into approximation equation (10). Note that a lookup table corresponding to approximation equation (10) may be stored in the storage device 32, and the voltage value E1 may be generated by referencing the lookup table.

[0083] Next, the calibration unit 311 of the second embodiment will be described. Note that the generation unit 312 is similar to that of the first embodiment in that it generates position data by using calibration data 322a and conversion data 322b, and therefore description thereof will be omitted. The calibration unit 311 acquires a voltage value Er of a voltage E corresponding to the amplitude δ of the K detection signals s in a first state in which the K keys 12 are located at the rest position Zr.

[0084] The calibration unit 311 calculates the deviation Δr by substituting the voltage value Er into equation (9). The calibration unit 311 estimates the voltage value E1 by substituting the deviation Δr into equation (10). Here, the normalized voltage En is given by equation (11). En=(E-E1) / (Ei-E1) En=E / (Ei-E1)-E1 / (Ei-E1) En=p*E+q…(11) However, p=1 / (Ei-E1), q=-E1 / (Ei-E1)

[0085] The calibration unit 311 generates a pair of constants p and q as calibration data 322a for each detection circuit 21, and stores the generated calibration data 322a in the storage device 32. That is, the calibration unit 311 calibrates the correspondence data 322 for each of the K keys 12 based on voltages E corresponding to the amplitudes of K detection signals s that correspond one-to-one to the K keys 12.

[0086] As described above, in the keyboard instrument 100 according to the second embodiment, when the K keys 12 are in the first state in which they are in the rest position Zr, the calibration unit 311 calibrates the correspondence data 322 for each of the K keys 12 based on the voltages E corresponding to the amplitudes of the K detection signals s output from the K detection circuits 21. Therefore, the installation error between the detection circuit 21 and the detected circuit 22 can be calibrated for each key 12.

[0087] C: Modified Example Specific modified embodiments that can be added to each of the embodiments exemplified above are exemplified below. Two or more embodiments arbitrarily selected from the following examples may be combined as appropriate within the scope of not being mutually contradictory.

[0088] (1) In each of the above-described embodiments, the detected circuit 22 includes a coil Lb made of a conductor, but the present disclosure is not limited to this. In short, the detected circuit 22 may be configured in any manner as long as it acts on the magnetic field generated by the detection circuit 21. For example, the detected circuit 22 may be configured of a magnetic material. Furthermore, the detected circuit 22 may be a plate-shaped conductor.

[0089] (2) In the above-described embodiments, the configuration for detecting the displacement of the key 12 of the keyboard instrument 100 has been exemplified, but the movable member whose displacement is detected by the detection system 20 is not limited to the key 12. Specific examples of the movable member are given below.

[0090] [Aspect A] FIG. 18 is a schematic diagram of a configuration in which a detection system 20 is applied to a string-striking mechanism 2A of a keyboard instrument 100. The string-striking mechanism 2A is an action mechanism that strikes the strings 13 in response to the displacement of each key 12 on the keyboard 10. Specifically, the string-striking mechanism 2A includes, for each key 12, a hammer 240 that can strike the strings by rotating, and a transmission mechanism (e.g., a wippen, jack, or repetition lever) that rotates the hammer 240 in response to the displacement of the key 12. The hammer 240 rotates around a support pin 242 as a rotation axis. The rotation of the hammer 240 causes a hammer head 241 to strike the strings 13. In the above configuration, the detection system 20 detects the displacement of the hammer 240. Specifically, a detection target circuit 22 is installed in the hammer 240 (e.g., a hammer shank 244). On the other hand, a detection circuit 21 is installed in a support member 243. As in the above-described embodiments, when the key 12 is in the rest position Zr, the detecting circuit 21 and the detected circuit 22 of the string-striking mechanism 2A are closest to each other. When the key 12 is in the end position Ze, the detecting circuit 21 and the detected circuit 22 are furthest apart. The support member 243 is, for example, a structure that supports the string-striking mechanism 2A. The hammer 240 is an example of a movable member that displaces within a movable range in response to playing movements. The support member 243 is an example of a fixed member that does not displace in response to playing movements. A string-striking mechanism 2A is provided for each key 12. Therefore, the keyboard instrument 100 has K hammers 240 in one-to-one correspondence with the K keys 12. Therefore, when calibrating the detection system 20 (hammer sensor) in the same manner as in the above embodiments, the output voltage E of the detection system 20 is measured for each key 12 when the key 12 is in the rest position Zr, and the voltage value E0 is estimated based on the average of the measurement results.

[0091] In the above configuration, because the key 12 and the hammer 240 are linked, the position for calibration is defined as a position during the stroke of the key 12, but it may also be defined as the position of the hammer 240. In this case, for example, the position where the string 13 and the tip of the hammer 240 come into contact is defined as the end position Ze, and the position where the hammer shank 244 is in contact with the hammer rail is defined as the rest position Zr, and the output value at the position where the string 13 and the tip of the hammer 240 come into contact is measured, and the voltage value E0 can be estimated based on the average value of the measurement results.

[0092] [Aspect B] FIG. 19 is a schematic diagram illustrating a configuration in which the detection system 20 is applied to a pedal mechanism 3A of a keyboard instrument 100. The pedal mechanism 3A includes a pedal 921 operated by a user's foot, a frame 920 that supports the pedal 921, and an elastic body 922 that urges the pedal 921 upward in the vertical direction. The pedal 921 rotates around a fulcrum 925. In the above configuration, the detection system 20 detects the displacement of the pedal 921. Specifically, the detection target circuit 22 is disposed on the upper surface of the pedal 921. Meanwhile, the detection circuit 21 is disposed on the frame 920 above the pedal 921 so as to face the detection target circuit 22. As with the above-described embodiments, in the pedal mechanism 3A, the detection circuit 21 and the detection target circuit 22 are closest to each other in a first state in which the user does not apply force to the pedal 921. Furthermore, when the user fully depresses the pedal 921, the detection circuit 21 and the detection target circuit 22 are furthest apart. Pedal 921 is an example of a movable member that is displaced within a movable range in response to a performance action. Frame 920 is an example of a fixed member that is not displaced in response to a performance action. Note that the instrument in which pedal mechanism 3A is used is not limited to keyboard instrument 100. For example, a pedal mechanism 3A with a similar configuration is used in any instrument, such as a percussion instrument. Also, in this example, detection target circuit 22 is disposed in pedal 921, but detection target circuit 22 may be disposed in a member connected to pedal 921, and detection circuit 21 may be disposed in a fixed member so as to face detection target circuit 22.

[0093] In addition, in the calibration of this aspect, when performing the same calibration as in each aspect, it is sufficient to measure the voltage E in the first state in which the user does not apply force to the pedal 921, and estimate the voltage value E0 based on the measurement result. Furthermore, when there are multiple pedals 921, it is sufficient to estimate the voltage value E0 based on the average value of the output values ​​of each pedal 921.

[0094] 19 illustrates a pedal mechanism 3A 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. 19. The pedal mechanism used in an electric musical instrument is an effect pedal operated by a user to adjust various sound effects such as distortion or compressor.

[0095] [Aspect C] In the above-described embodiments, the detection circuit 22 is disposed on the underside of the key 12, and the detection circuit 21 is disposed opposite the detection circuit 22, but the present disclosure is not limited to this. Fig. 20 is a schematic diagram of a configuration in which the detection system 20 is applied to a keyboard mechanism 4A of a keyboard instrument 100.

[0096] The keyboard mechanism 4A includes a key 12, a connection portion 180, a hammer assembly 200, and a frame 500. The frame 500 is fixed to the housing 90. The connection portion 180 connects the key 12 to the frame 500 so that the key 12 can rotate relative to the frame 500. The connection portion 180 includes a plate-shaped flexible member 181, a support portion 183, and a rod-shaped flexible member 185. The plate-shaped flexible member 181 extends from the rear end of the key 12. The support portion 183 extends from the rear end of the plate-shaped flexible member 181. The rod-shaped flexible member 185 is supported by the support portion 183 and the frame 500. In other words, the rod-shaped flexible member 185 is disposed between the key 12 and the frame 500. The rod-shaped flexible member 185 bends elastically, allowing the key 12 to rotate relative to the frame 500.

[0097] A pressing unit 120 is also connected to the key 12. When the key 12 rotates, the pressing unit 120 rotates the hammer assembly 200 by pressing. The hammer assembly 200 is disposed in the space below the key 12 and is rotatably attached to the frame 500. The hammer assembly 200 includes a weight unit 230 and a hammer main body 250. The hammer main body 250 is provided with a shaft support unit 220 that serves as a bearing for the rotation shaft 520 of the frame 500. The shaft support unit 220 and the rotation shaft 520 of the frame 500 are in slidable contact with each other at at least three points.

[0098] The weight section 230 includes a metal weight and is connected to the rear end of the hammer body 250 (farther back than the pivot shaft). Normally (when no key is pressed), the weight section 230 rests on the lower stopper 410. This stabilizes the key 12 in the rest position. When the key is pressed, the weight section 230 moves upward and hits the upper stopper 430. This defines the end position where the key 12 can be pressed to the maximum extent.

[0099] In the above configuration, the detection system 20 detects the displacement of the key 12. Specifically, the detection target circuit 22 is installed on the upper surface of the portion of the key 12 located inside the frame 500. Meanwhile, the detection circuit 21 is installed on the underside of a base 550 attached to the inner circumferential surface of the frame 500. In the keyboard mechanism 4A, as in the above-described embodiments, the detection circuit 21 and the detection target circuit 22 are closest to each other when the key 12 is in the rest position Zr. Furthermore, the detection circuit 21 and the detection target circuit 22 are furthest apart when the key 12 is in the end position Ze. The base 550 is an example of a fixed member that does not displace in response to playing movements. The key 12 is an example of a movable member that displaces within a movable range in response to playing movements. Alternatively, as shown by the dotted line in FIG. 20 , the detection circuit 21 may be installed on a base 560 attached to the housing 90, and the detection target circuit 22 may be installed on the underside of the hammer body 250.

[0100] Furthermore, while the above-described embodiments have been described as examples of configurations for detecting each key 12 of the keyboard instrument 100, the objects to be detected by the detection system 20 are not limited to these examples. For example, the detection system 20 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).

[0101] As can be understood from the above examples, the object of detection by the detection system 20 is generally expressed as a movable member that displaces in response to a performance action. The movable member includes performance controls such as the keys 12 or pedals 921 that are directly operated by the user, as well as structures such as the hammer 240 that displace in response to the operation of the performance controls. However, the movable member in this disclosure is not limited to a member that displaces in response to a performance action. In other words, the movable member is generally expressed as a member that can be displaced regardless of the trigger that causes the displacement.

[0102] (3) In the above-described embodiments, the keyboard instrument 100 is provided with the tone generator circuit 34. However, in a configuration in which the keyboard instrument 100 is provided with a sound generating mechanism such as a string striking mechanism 2A or 2B, the tone generator circuit 34 may be omitted. The detection system 20 is used to record the performance of the keyboard instrument 100.

[0103] As can be understood from the above explanation, the present disclosure can also be specified as a device (operation device) that controls musical tones by outputting operation signals corresponding to performance actions to a sound source circuit 34 or a sound generation mechanism. The concept of an operation device encompasses not only musical instruments (keyboard instruments 100) equipped with a sound source circuit 34 or a sound generation mechanism as exemplified in the above embodiments, but also devices that do not have a sound source circuit 34 or a sound generation mechanism (for example, a MIDI controller or the pedal mechanisms 3A and 3B described above). In other words, the performance operation device in the present disclosure is comprehensively expressed as a device that a performer (operator) operates to perform a performance.

[0104] D: Notes From the above-described exemplary embodiments, the following configurations can be understood, for example.

[0105] A musical instrument according to one aspect (Aspect 1) of the present disclosure includes a fixed member, a movable member that is displaced relative to the fixed member from a first state in an initial position to a second state in response to a performance action of the musical instrument, a detectable circuit mounted on the movable member and having a magnetic or conductive material, and a detection circuit having a coil disposed on the fixed member and outputting a detection signal whose voltage corresponds to the distance between the detectable circuit and the coil, wherein the distance between the detectable circuit and the coil in the first state is shorter than the distance between the detectable circuit and the coil in the second state. In the first state, when no force due to a performance action is applied to the movable member, the distance D is shorter than the distance in the second state, when a force is applied to the movable member. In other words, the distance is minimum in the first state (Aspect 2). The shorter the distance, the smaller the amplitude of the detection signal. Therefore, when the user is not pressing down on the movable member, the amplitude of the detection signal is small. Therefore, in the first state, unwanted radiation noise caused by the amplitude of the detection signal can be reduced.

[0106] A musical instrument according to one aspect (aspect 3) of the present disclosure includes a calibration unit that calibrates the correspondence between the voltage of the detection signal and the position of the movable member based on the voltage of the detection signal in the first state, and a generation unit that generates position data indicating the position of the movable member based on the voltage in the second state using the correspondence calibrated by the calibration unit. The first state is a state in which no force due to a playing action is applied to the movable member, and therefore calibration is performed when the user is not playing.

[0107] In a musical instrument according to one aspect (aspect 4) of the present disclosure, the calibration unit calibrates the correspondence during a period from when the power is turned on until a predetermined time has elapsed. During this period, the user is likely not planning to start playing, so the correspondence can be calibrated without the user being aware of the calibration. As a result, the accuracy of the position data is improved by calibrating the voltage variations caused by the mounting positions of the detection circuit and the detected circuit. Furthermore, by calibrating every time the power is turned on, the voltage variations caused by the temperature characteristics and aging of the detection circuit and the detected circuit can be calibrated.

[0108] In a musical instrument according to one aspect (aspect 5) of the present disclosure, the movable member is one of K (K is an integer of 2 or greater) movable members that are displaced within a movable range in response to a playing action, the detected circuit is one of K detected circuits that correspond one-to-one to the K movable members, the K detected circuits are installed on the K movable members in one-to-one correspondence, and the detection circuit is one of the K detection circuits that correspond one-to-one to the K detected circuits, and the calibration unit calculates an average voltage value for the K detection signals output from the K detection circuits when the K movable members are in the first state, and calibrates the correspondence relationship based on the calculated average voltage value. According to this aspect, the correspondence relationship is calibrated based on the average voltage value, thereby reducing the processing load related to the calibration.

[0109] In a musical instrument according to one aspect (aspect 6) of the present disclosure, the K movable members are preferably K keys. According to this aspect, variations in the mounting positions of the K keys can be calibrated.

[0110] In a musical instrument according to one aspect (aspect 7) of the present disclosure, it is preferable that the musical instrument includes K keys and K hammers that correspond one-to-one to the K keys, and the K movable members are the K hammers. According to this aspect, it is possible to calibrate variations in the mounting positions of the K hammers.

[0111] In a musical instrument according to one aspect (aspect 8) of the present disclosure, the movable member is preferably a pedal or a member connected to the pedal. According to this aspect, variations in the mounting position of the pedal or the member connected to the pedal can be calibrated. [Explanation of symbols]

[0112] 100...keyboard instrument, 10...keyboard, 12...key, 121...end, 122...installation surface, 14...support member, 20...detection system, 21...detection circuit, 211...resonance circuit, 22...detected circuit, 221...resonance circuit, 23...drive circuit, 30...information processing device, 31...control device, 32...memory device, 34...sound source circuit, 40...sound emission device

Claims

1. A fixing member; a movable member that is displaced relative to the fixed member from a first state in an initial position to a second state in response to a playing action of the musical instrument; a plate-shaped detection target portion including a magnetic material or a conductor, which is displaced in accordance with the displacement of the movable member; a detection circuit having a coil disposed on the fixed member and outputting a detection signal having a voltage corresponding to the distance between the detected part and the coil; the distance between the detected portion and the coil is minimized in the first state; the second state is a state in which the movable member is displaced in response to the playing action, when the position of the movable member is at the initial position in the first state among the initial position in the first state and all positions in the second state, the amplitude of the detection signal is minimum. Performance operation device.

2. a calibration unit that calibrates a correspondence relationship between a voltage of the detection signal and a position of the movable member based on the voltage of the detection signal in the first state; a generating unit that generates position data indicating a position of the movable member based on the voltage in the second state using the correspondence calibrated by the calibrating unit; 2. The performance operation device according to claim 1, comprising:

3. 3. The musical performance operation device according to claim 2, wherein the calibration section calibrates the correspondence during a period from when the power is turned on until a predetermined time has elapsed.

4. The movable member is a first movable member, a set of K (K is an integer of 2 or more) movable members including the first movable member that are displaced within a movable range in response to the playing action; the detected portion is a first detected portion, K detection parts including the first detection part are provided in one-to-one correspondence with the K movable members, the K detection portions are provided on the K movable members in one-to-one correspondence; the detection circuit is a first detection circuit; K detection circuits each corresponding to the K detection target units on a one-to-one basis, each including the first detection circuit; the calibration unit calculates an average value of the voltages of the K detection signals output from the K detection circuits when the K movable members are in the first state, and calibrates the correspondence relationship based on the calculated average value of the voltages.

4. The performance operation device according to claim 2 or 3.

5. 5. The musical performance operation device according to claim 4, wherein said K movable members are K keys.

6. K keys, K hammers corresponding one-to-one to the K keys, the K movable members are the K hammers, 5. The performance operation device according to claim 4.

7. 4. The performance operation device according to claim 1, wherein the movable member is a pedal or a member connected to the pedal.

8. A fixing member; a movable member that is displaced relative to the fixed member from a first state in an initial position to a second state in response to a playing action of the musical instrument; a plate-shaped detection target portion including a magnetic material or a conductor, which is displaced in accordance with the displacement of the movable member; a detection circuit having a coil disposed on the fixed member and outputting a detection signal having a voltage corresponding to the distance between the detected part and the coil; the distance between the detected portion and the coil is minimized in the first state; the second state is a state in which the movable member is displaced in response to the playing action, when the position of the movable member is at the initial position in the first state among the initial position in the first state and all positions in the second state, the amplitude of the detection signal is minimum. Keyboard mechanism.

9. 9. A keyboard mechanism according to claim 8, wherein the movable member is a key.

10. Multiple keys and a plurality of hammers corresponding one-to-one to the plurality of keys; The movable member is the hammer.

9. A keyboard mechanism according to claim 8.

11. A fixing member; a movable member that is displaced relative to the fixed member from a first state in an initial position to a second state in response to a playing action of the musical instrument; a plate-shaped detection target portion including a magnetic material or a conductor, which is displaced in accordance with the displacement of the movable member; a detection circuit having a coil disposed on the fixed member and outputting a detection signal having a voltage corresponding to the distance between the detected part and the coil; the distance between the detected portion and the coil is minimized in the first state; the second state is a state in which the movable member is displaced in response to the playing action, when the position of the movable member is at the initial position in the first state among the initial position in the first state and all positions in the second state, the amplitude of the detection signal is minimum. Pedal mechanism.

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