Operation position output device, operation position output method and program

Abstract

To improve accuracy of position detection of a movable member.SOLUTION: An operation position output device includes: a fixing member; a movable member which is displaced with respect to the fixing member within a movable range according to operation of a user; a detected member installed in the movable member; a detection circuit which is arranged in the fixing member and outputs a detection signal with a value corresponding to a position of the movable member within the movable range; a generation part for generating position data indicating the position of the movable member, which corresponds to the value of the detection signal, based on correspondence between the value of the detection signal and the position of the movable member; and a calibration part for calibrating correspondence based on the value of the detection signal when the position of the movable member is a prescribed position within the movable range and the value of the detection signal when the movable member does not exist.SELECTED DRAWING: Figure 13

Description

[Technical field]

[0001] The present disclosure relates to a technology for outputting an operation position. [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. [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] In the configuration of Patent Document 1, the excitation coil and the position detection coil are arranged on a fixed member, and the excited coil is arranged on a movable member. The relative positions of the excitation coil and the position detection coil, and the excited coil vary depending on the mounting position. If there is variation in the relative positions of the position detection coil and the excited coil, there is a problem that the position of the movable member cannot be detected accurately. The present disclosure aims to solve an issue of improving the detection accuracy of the position of a movable member by absorbing variations in the position of a coil or the like. [Means for solving the problem]

[0005] In order to solve the above problems, a musical instrument according to one aspect of the present disclosure comprises a fixed member, a movable member that displaces relative to the fixed member within a movable range in response to the playing action of the musical instrument, a detectable circuit mounted on the movable member and having a magnetic material or a conductor, a detection circuit having a coil arranged on the fixed member and outputting a detection signal whose voltage corresponds to the distance between the detectable circuit and the coil, a generation unit that generates position data indicative of the position of the movable member based on a correspondence between the voltage of the detection signal and the position of the movable member, and a calibration unit that calibrates the correspondence based on the value of the voltage when the position of the movable member is at a predetermined position within the movable range. [Brief description of the drawings]

[0006] [Figure 1] 1 is a block diagram illustrating a configuration of a keyboard instrument according to a first embodiment. [Diagram 2] FIG. 1 is a block diagram illustrating a configuration of a keyboard instrument. [Diagram 3] FIG. 2 is a circuit diagram of a detection circuit and a detected circuit. [Figure 4] FIG. 2 is a block diagram illustrating a configuration of a drive circuit. [Diagram 5] FIG. 4 is a plan view of a signal conversion unit. [Figure 6] 6 is a cross-sectional view of line a in FIG. 5. [Figure 7] 4 is an explanatory diagram of a magnetic field generated in a signal conversion unit. FIG. [Figure 8] 4 is a circuit diagram illustrating a specific configuration of a resonant circuit in a detected circuit. FIG. [Figure 9] FIG. 2 is a plan view of a detected circuit. [Figure 10] 10 is a cross-sectional view taken along the line bb in FIG. 9. [Figure 11A] 1 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 seen from the normal direction of the coil La. [Figure 11B] 1 is a graph showing characteristics N0, N1, and N2 that indicate the relationship between distance D and voltage E. [Figure 12]1 is a graph showing normalized characteristics N. [Figure 13] FIG. 2 is a functional block diagram showing 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] 5 is a flowchart showing the operation of the control device 31 in a calibration mode. [Figure 16] 4 is a flowchart showing the operation of the control device 31 in a performance mode. [Figure 17] 13 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] A curve C6 showing the relationship between the amount of deviation Δr and a voltage value E6, and a curve C1 showing the relationship between the amount of deviation Δr and a voltage value E1 are shown. [Figure 19] 1 is a graph showing the normalized slope of voltage E versus distance D. [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. [Figure 21] 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 22] 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 23] 1 is a schematic diagram of a configuration in which a detection system 20 is applied to a keyboard 10B of a keyboard instrument 100. FIG. [Figure 24] 13 is a graph showing characteristics N0, N1, and N2 that indicate the relationship between distance D and voltage E according to a modified example. [Diagram 25] 13 is a graph showing normalized characteristics N according to a modified example. [Figure 26] 13 is a graph showing the relationship between voltage E and normalized voltage En according to a modified example. [Figure 27] 1 is a schematic diagram of a configuration in which a detection system 20 is applied to a string striking mechanism 2B of a keyboard instrument 100. FIG. [Figure 28]1 is a schematic diagram of a configuration in which a detection system 20 is applied to a pedal mechanism 3B of a keyboard instrument 100. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] A: First embodiment 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 10A, 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 10A is composed of K keys 12 including white keys and black keys, where K is an integer equal to or greater than 2. K is, for example, "88."

[0008] Each of the K keys 12 is displaceable within a movable range. Each of the K keys 12 is an example of a movable member that is displaced in response to a playing action by a user. The detection system 20 detects the position of each key 12. The information processing device 30 generates an audio signal V in response to the result of detection 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 a headphone is used as the sound emitting device 40.

[0009] FIG. 2 is a block diagram illustrating a specific configuration of the keyboard instrument 100, focusing on one of the keys 12 on the keyboard 10A. Each key 12 on the keyboard 10A is supported by a support member 14 with a fulcrum portion (balance pin) 13 as a fulcrum. The support member 14 is a structure (frame) that supports each element of the keyboard instrument 100. The support member 14 does not move in response to a performance action. The support member 14 is an example of a fixed member. An end 121 of each key 12 is displaced in the vertical direction when the user presses and releases the key. In the following description, the position of the end 121 of the key 12 is referred to as the position Z of the key 12. An initial state in which no force due to a performance action acts on the key 12 is referred to as the first state, and a state in which a force due to a performance action or a static load for calibration 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 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 (rest position Zr) of the end 121 in a first state in which no load is applied to the key 12.

[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 (hereinafter referred to as the "installation surface") 122 of the key 12. The drive circuit 23 and the 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 between 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 according to the distance between the coils La and Lb.

[0013] 3 is a circuit diagram illustrating an example of the electrical configuration of the detection circuit 21 and the detected circuit 22 corresponding to any one of the keys 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 driving circuit 23. The driving 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 periodically varies. For example, a periodic signal of 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 time length of the period during which the reference signal W is supplied to one detection circuit 21. In addition, the frequency of the reference signal W is set to a frequency approximately equal to the resonant frequency of the resonant circuit 211 and the resonant circuit 221.

[0016] The reference signal W is supplied to the coil La via the input terminal T1 and the resistance element R. The supply of the reference signal W generates a magnetic field in the coil La. An induced current is generated in the coil Lb of the detected circuit 22 by electromagnetic induction due to the magnetic field generated in the coil La. That is, a magnetic field is generated in the coil La in a direction that offsets the change in the magnetic field of 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 according to the distance D. Therefore, the amplitude δ of the detection signal s changes according to the distance D. The detection circuit 21 outputs the detection signal s having an amplitude δ according 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 in the coil La to offset the magnetic field generated in the coil Lb. In this embodiment, when the key 12 is located at the end position Ze, the coils La and Lb are closest to each other, and the distance D is the smallest. Therefore, when the key 12 is in the end position Ze, the amplitude δ of the detection signal s is at a 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 at a minimum in the first state.

[0017] The output circuit 232 in Fig. 4 is a multiplexer that generates a detection signal S by arranging on a time axis the detection signals s output in sequence from each of the multiple detection circuits 21. The output circuit 232 generates the detection signal S by time-division multiplexing the K detection signals s. In other words, 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 described 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 is expressed as a signal that corresponds to the position Z of each of the K keys 12.

[0018] 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 in which signals indicating the voltage E corresponding to the amplitude δ of each detection signal s are time-division multiplexed. The amplitude detection circuit 24 outputs the amplitude signal A to the information processing device 30. Note that the detection system 20 may 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.

[0019] 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 detected circuit 22 side (vertically above). Fig. 6 is a cross-sectional view of 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.

[0020] The detection circuit 21 is a circuit board 50 including a substrate 51 on which a resonant circuit 211 is disposed. 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.

[0021] On the substrate 51, a wiring pattern 52-1 and a wiring pattern 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.

[0022] 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.

[0023] Each of the first coil portion La1 and the second coil portion La2 is formed in a rectangular spiral shape. The first coil portion La1 and the second coil portion La2 have the same spiral direction. For example, the first coil portion La1 and the second coil portion La2 form a counterclockwise spiral shape 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 along a direction perpendicular to the direction (horizontal direction) in which the K keys 12 are arranged.

[0024] 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 penetrating the substrate 51. As described above, the first coil portion La1 and the second coil portion La2 are mutually electrically connected via the connection portion La3. The first coil portion La1, the second coil portion La2, and the connection portion La3 form the coil La in FIG. 3.

[0025] 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).

[0026] A magnetic field is generated in each of the first coil section La1 and the second coil section La2 by supplying a current. As can be seen from FIG. 5, the direction of the current flowing in the first coil section La1 is opposite to the direction of the current flowing in the second coil section La2. Therefore, as illustrated in FIG. 7, a magnetic field in the opposite direction is generated 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. According to 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, so that the diffusion of the magnetic field between the adjacent keys 12 is reduced. That is, the interference of the magnetic field between two adjacent coils Lb is reduced. Therefore, a detection signal s that reflects the position Z of each of the K keys 12 with high accuracy can be generated.

[0027] 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.

[0028] The capacitive element Cb illustrated in FIG. 3 is actually composed of four capacitive elements Cb1 to Cb4. The four capacitive elements Cb1 to Cb4 are connected in parallel between the wiring 651 and the 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.

[0029] 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 viewed 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, an X-axis and a Y-axis are assumed to be 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 is hereinafter referred to as "planar view."

[0030] The detected circuit 22 is a circuit board 60 including a substrate 61 on which a resonant circuit 221 is disposed. 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.

[0031] The substrate 61 includes a plurality of regions (Q11, Q12, Q13, Q21, Q22, Q23) arranged along the Y axis. The regions Q11 and Q21 are regions of the substrate 61 near the center in the Y axis direction. The region Q11 is located in the negative direction of the Y axis with respect to the midpoint of the substrate 61 in the Y axis direction, and the region Q21 is located in the positive direction of the Y axis with respect to the midpoint. The region Q13 is a region including an end portion 614 of the substrate 61 located in the negative direction of the Y axis. The region Q12 is a region between the regions Q11 and Q13. Similarly, the region Q23 is a region including an end portion 615 of the substrate 61 located in the positive direction of the Y axis, and the region Q22 is a region between the regions Q21 and Q23.

[0032] The first coil portion Lb1 is formed in the region Q11. The capacitance elements Cb1 and Cb2 are formed in the region Q13. The capacitance elements Cb1 and Cb2 are arranged in the region Q13 at intervals in the X direction in a plan view. As can be understood from the above explanation, the capacitance elements Cb1 and Cb2 are formed between the first coil portion Lb1 and the end 614 of the substrate 61 in a plan view. That is, the capacitance 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 the region Q12.

[0033] 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 influenced by the capacitance elements Cb1 and 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.

[0034] 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 a position spaced apart from the second coil portion Lb2 in the positive direction of the Y axis by an interval corresponding to region Q12. Therefore, it is easy to ensure the distance between the capacitive elements Cb3 and Cb4 and the second coil portion Lb2.

[0035] As can be understood from the above example, in a plan view, the coil Lb (first coil portion Lb1 and second coil portion Lb2) is located between the set of the capacitance element Cb1 and the capacitance element Cb2 and the set of the capacitance element Cb3 and the capacitance element Cb4. The above configuration has the advantage that it is easier to ensure the electrostatic 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, as compared to a configuration in which the capacitance element Cb is formed between the first coil portion Lb1 and the second coil portion Lb2, for example.

[0036] Returning to Fig. 2 for the 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 realized as a computer system comprising a control device 31, a storage device 32, an A / D converter 33, and a sound source circuit 34. The information processing device 30 may be realized as a single device, or as a plurality of devices configured separately from each other.

[0037] 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).

[0038] The storage device 32 is a single or multiple memories that store a program 321 executed by the control device 31 and correspondence data 322. The correspondence data 322 is data indicating the correspondence between a voltage E corresponding to an 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 used to generate a normalized voltage En, which will be described later, from a voltage E corresponding to the amplitude δ of the detection signal s. The conversion data 322b is data indicating the correspondence between a normalized voltage En and a position Z. The storage device 32 also functions as a working area for the control device 31. The storage device 32 is configured with a known recording medium, such as a magnetic recording medium or a semiconductor recording medium. The storage device 32 may be configured with a combination of multiple types of recording media. The storage device 32 may also be a portable recording medium that is detachable from the keyboard instrument 100, or an external recording medium (e.g., online storage) with which the keyboard instrument 100 can communicate.

[0039] 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 tone instructed by the control device 31. Specifically, an audio signal V representing a musical tone of a pitch corresponding to the key 12 whose position Z has changed among a plurality of pitches is generated. The volume of the audio signal V is controlled, for example, according to the speed at which the position Z changes. The audio signal V is supplied from the sound source circuit 34 to the sound emitting device 40, and a musical tone corresponding to the playing action (depression or release of each key 12) by the user is emitted from the sound emitting device 40. The control device 31 may realize the function of the sound source circuit 34 by executing a program 321 stored in the storage device 32.

[0040] 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 by the formula Δr=(Δx 2 +Δy 2 ) 1 / 2 Here, 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.

[0041] FIG. 11B is a graph showing characteristics N0, N1, and N2 that indicate the relationship between distance D and voltage E. Characteristic N0 is a curve that indicates the relationship between distance D and voltage E when the amount of deviation Δr is zero, i.e., when viewed in a plan view, the central axis C1 of coil La and the central axis C2 of coil Lb coincide with each other. Furthermore, characteristic N1 is a curve that indicates the relationship between distance D and voltage E when the amount of deviation Δr=r1. Furthermore, characteristic N2 is a curve that indicates the relationship between distance D and voltage E when the amount of deviation Δr=r2, where r2>r1.

[0042] 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.

[0043] 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 end position Ze, the coils La and Lb are closest to each other. The distance De in this case is 3 mm. Meanwhile, when the key 12 is in the rest position Zr, the coils La and Lb are farthest apart. The distance Dr in this case is 10 mm.

[0044] However, there is variation between the attachment position of the detection circuit 21 disposed on the support member 14 and the attachment position of the detected circuit 22 disposed on the key 12. For this reason, the relationship between the distance D and the voltage E varies for each key 12, such as 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 that constitute the detection circuit 21 also vary. The relationship between the distance D and the voltage E also varies for each key 12 due to variations in the values ​​of these elements, as well as the temperature characteristics and aging of these elements.

[0045] In this embodiment, in order to absorb various variations, the multiple characteristics shown in Fig. 11B are normalized to normalized characteristic N shown in Fig. 12, and distance D is obtained from voltage E using normalized characteristic N. Normalized characteristic N indicates the relationship between normalized voltage En obtained by normalizing voltage E and distance D. The normalized voltage En is given by equation (1). E = (E - E0) / (Ei - E0) ... (1) Here, E0 is the voltage value of voltage E when distance D is zero. That is, E0 is the voltage value of voltage E when detection circuit 21 and detected circuit 22 are in contact. Ei is the voltage value of voltage E when distance D is infinite. That is, Ei is the value of voltage E when detected circuit 22 is not present. The normalized voltage En varies in the range of 0 to 1.

[0046] By the way, in the state before the K detection circuits 21 are arranged on the support member 14 and the K keys 12 are assembled into the keyboard instrument 100, there is no detected circuit 22 paired with the detection circuit 21. Therefore, in this state, the voltage value Ei can be measured. On the other hand, the voltage value E0 cannot be measured if there is no detected circuit 22 paired with the detection circuit 21. Therefore, the voltage value E0 needs to be measured in the state in which the K keys 12 to which the detected circuits 22 are attached are assembled into the keyboard instrument 100. However, since the keys 12 can only be displaced up to the end position Ze, the voltage value E0 cannot be measured. Therefore, in this embodiment, the voltage value E0 is estimated based on the end voltage value Ee of the voltage E at the end position Ze, and the normalized voltage En is calculated using the estimated voltage value E0.

[0047] 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 end position Ze where the distance D is smallest within the movable range. The end position Ze is an example of a predetermined position within the movable range of the key 12 (movable member). In addition, the end position Ze is the position Z of the key 12 where the distance D is smallest within the movable range of the key 12.

[0048] The normalized characteristic N indicates the relationship of the normalized voltage En to 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 formula (2). Meanwhile, the inverse function is given by formula (3). En = F(D)…(2) D=F -1 (En)…(3)

[0049] 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.

[0050] The operation modes of the keyboard instrument 100 are roughly divided into a calibration mode and a performance mode. A setting unit 310, which will be described later, switches the operation 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 and the like. In the performance mode, the control device 31 also detects an amplitude signal A corresponding to the performance action of the user, and generates an audio signal V based on the detected amplitude signal A.

[0051] 13 is a functional block diagram showing the functions of the control device 31. The control device 31 reads out a program 321 from the storage device 32 and executes the read out program, thereby functioning as a setting unit 310, a calibration unit 311, a generation unit 312, and a sound source control unit 313.

[0052] The setting unit 310 sets the operation mode of the keyboard instrument 100 to a calibration mode or a performance mode in response to a user's operation. For example, if the keyboard instrument 100 is provided with a setting button, the setting unit 310 sets the operation mode of the keyboard instrument 100 to a calibration mode or a performance mode based on an operation signal output from the setting button. The setting unit 310 may normally select the performance mode, and may select the calibration mode when it detects that a plurality of keys 12 out of the K keys 12 are pressed simultaneously. For example, the setting unit 310 may select the calibration mode when the leftmost key 12 and the rightmost key 12 out of the K keys are pressed simultaneously.

[0053] The calibration unit 311 operates in a 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 a 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.

[0054] As described above, K voltages E in one-to-one correspondence with the K detection circuits 21 are time-division multiplexed in the amplitude signal A. When the key 12 is in the second state and is pressed all the way down, the position Z of the key 12 is the end position Ze. The voltage E when the key 12 is in the end position Ze is referred to as the end voltage value Ee. In the second state in which the key 12 is in the end position Ze, the calibration unit 311 calculates an average end voltage value Eea, which is the average value of the K end voltage values ​​Ee, based on the amplitude signal A. The average end voltage value Eea is given by the following equation (4). Eea = (Ee1 + Ee2 + ... + EeK) / K ... (4) Here, Ee1, Ee2, . . . EeK are end voltage values ​​Ee that correspond one-to-one to the K keys 12.

[0055] The calibration unit 311 estimates the voltage value E0 based on the average end voltage value Eea. Fig. 14 shows the relationship between the voltage E and the normalized voltage En. The voltage value Ene is the value of the normalized voltage En when the key 12 is located at the end position Ze. The voltage value Ene is known. The voltage value Ei is also known. Therefore, E0 can be calculated by substituting the average end voltage value Eea into equation (1). Substituting the average end voltage value Eea and the voltage value Ene into equation (1) gives equation (5). Ene = (Eea - E0) / (Ei - E0) ... (5) By transforming equation (5), equation (6) is derived. E0 = (Eea-Ene*Ei) / (1-Ene)…(6) Calibration unit 311 estimates voltage value E0 using equation (6).

[0056] The reason why the voltage value E0 is estimated using the average end voltage value Eea is as follows. The first reason is that the end voltage value Ee can be measured without a jig or the like when the key 12 is located at the end position Ze. In this embodiment, the key 12 is located at the end position Ze by applying to the key a static load necessary and sufficient to press down the key from a first state in which no force due to the playing action acts on the key 12. Then, the voltage value E0 is estimated when the power of the keyboard instrument 100 is turned on and the calibration mode is selected by the setting unit 310.

[0057] The second reason is that the end position Ze has less variation compared to other positions within the movable range.

[0058] The third reason is that the distance De at the end position Ze is 3 mm on average, and the voltage value of the normalized voltage En for the distance De is Ene. The actual voltage value Ene 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 De for each key 12, and it is known that the average value of the distance De is 3 mm. Therefore, there is little need to estimate the voltage value E0 for each key 12. Also, since there is no need to estimate the voltage value E0 for each end voltage value Ee, the processing load on the control device 31 can be reduced.

[0059] 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. 14. Therefore, the voltage E and the normalized voltage En have a relationship represented by the following formula (7). E = p * E + q … (7) Here, 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)

[0060] 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 K detection circuits 21. When generating a pair of constants p and q for each detection circuit 21, the calibration unit 311 generates a 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 K detection circuits 21, the calibration unit 311 generates a pair of constants p and q based on the average voltage of the voltage value Ei measured for each detection circuit 21 and the voltage value E0 common to the K detection circuits 21.

[0061] The correction unit 312a uses the calibration data 322a to correct the voltage E, thereby generating 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.

[0062] Next, the operation of the control device 31 will be described separately for the calibration mode and the performance mode. Fig. 15 is a flow chart showing the operation of the control device 31 in the calibration mode. The operation of Fig. 15 is executed when the power of the keyboard instrument 100 is turned on and the calibration mode is selected by the setting unit 310. In the calibration mode, the control device 31 functions as a calibration unit 311.

[0063] First, the control device 31 sets a variable k to "1" (S11). Next, the control device 31 obtains an end voltage value Ee at the end position Ze of the key 12 (S12). As described above, the key 12 is located at the end position Ze in the second state. Therefore, no special work such as arranging a jig or the like in advance is required to position the key 12 at the end position Ze. The control device 31 obtains the voltage E of the amplitude signal A corresponding to the kth key 12 as a rest voltage value Er.

[0064] 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 formula (4) (S15).

[0065] Next, the control device 31 estimates the voltage value E0 based on the average end voltage value Eea, the voltage value Ei, and the voltage value Ene of the normalized voltage En corresponding to the distance De (S16). After that, 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).

[0066] 16 is a flow chart showing the operation of the control device 31 in the performance mode. When the setting unit 310 has selected the performance mode, the operation of FIG. 16 is executed. 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).

[0067] 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 substitutes the pair of constants p and q indicated by the calibration data 322a and the voltage E into equation (7) to calculate the normalized voltage En. In step S22, the control device 31 functions as a correction unit 312a.

[0068] 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.

[0069] 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 judges whether or not it is in the performance mode (S26). If the judgment result in step S26 is positive, the control device 31 returns the process to step S21. If the judgment result in step S26 is negative, the control device 31 ends the performance mode.

[0070] As described above, in the keyboard instrument 100 according to the first embodiment, the generation unit 312 generates position data indicating the position Z of the key 12 corresponding to the amplitude of the detection signal s, based on the correspondence between the voltage E corresponding to the amplitude δ of the detection signal s and the correspondence data 322 regarding the correspondence between the position Z of the key 12 and the voltage E corresponding to the amplitude δ of the detection signal s. In addition, the calibration unit 311 calibrates the correspondence data 322 based on the voltage E corresponding to the amplitude of the detection signal s when the position of the key 12 is a predetermined position within the movable range of the key 12. Since the predetermined position is included in the movable range, the correspondence data 322 can be calibrated with the detection circuit 21 and the detected circuit 22 incorporated in the keyboard instrument 100.

[0071] In the first embodiment, the end position Ze is used as the predetermined position within the movable range. The end position Ze, where the distance D is the smallest, and the rest position Zr, where the distance D is the largest, within the movable range, are easy to position the key 12 at. Furthermore, as shown in Fig. 11B, the change in voltage E with respect to the amount of deviation Δr is larger at the end position Ze than at the rest position Zr. Therefore, the accuracy of the calibration is improved by calibrating the correspondence data 322 based on the end voltage value Ee corresponding to the amplitude of the detection signal s when the key 12 is located at the end position Ze.

[0072] Furthermore, the calibration unit 311 estimates a voltage value E0 corresponding to the position Z of the key 12 where the distance D is zero based on the end voltage value Ee corresponding to the end position Ze, 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 end position Ze 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 end position Ze. Therefore, by calibrating the correspondence data 322 based on the estimated voltage value E0, the accuracy of the calibration is improved.

[0073] Furthermore, when the position Z of each of the K keys 12 is at the end position Ze within the movable range, the calibration unit 311 calculates an average end voltage value Eea, which is the average value of the voltages E corresponding to the amplitudes, for the K detection signals s output from the K detection circuits 21, and calibrates the correspondence data 322 based on the calculated average end voltage value Eea. Since there is no need to estimate the voltage value E0 for each end voltage value Ee, the processing load on the control device 31 can be reduced.

[0074] B: Second embodiment The keyboard instrument 100 of the first embodiment described above estimates the voltage value E0 common to each detection circuit 21 based on the voltage value Ene of the normalized voltage En corresponding to the end position Ze and the average end voltage value Eea. In contrast, the keyboard instrument 100 of the second embodiment differs from the keyboard instrument 100 of the first embodiment in that the keyboard instrument 100 estimates the voltage value E1 of the voltage E when the distance D is 1 mm for each detection circuit 21 based on the voltage value E6 of the voltage E when the distance D is 6 mm. 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 E0 in the calibration unit 311. The keyboard instrument 100 of the second embodiment will be described below, focusing on the differences.

[0075] FIG. 17 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. As described with reference to FIG. 11A, the amount of deviation Δr indicates the distance between the central axis C1 of the coil La and the central axis C2 of the coil Lb in a plan view. As shown in FIG. 17, the voltage E when the distance D is 1 mm depends on the amount of deviation Δr. Therefore, if the amount of deviation Δr can be specified, 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 is referred to as "E1."

[0076] The voltage value E1 is close enough to be approximated to the voltage value E0. However, the voltage value E1 is the voltage E when the distance D is 1 mm, and therefore cannot be actually measured. Therefore, the control device 31 needs to estimate the voltage value E1.

[0077] Next, a method for estimating the voltage value E1 will be described. Fig. 18 shows a curve G6 indicating the relationship between the deviation amount Δr and the voltage value E6, and a curve G1 indicating the relationship between the deviation amount Δr and the voltage value E1. The black circles shown in Fig. 18 are points plotted for the voltage value E6 measured when the deviation amount Δr is changed. The white triangles are points plotted for the voltage value E1 measured when the deviation amount Δr is changed.

[0078] Here, the curve G6 is given by the following quadratic approximation equation (8). E6=h2*Δr 2 +h1*Δr+h0…(8) Here, h2, h1, and h0 are constants.

[0079] If the voltage value E6 can be measured, the deviation amount Δr can be calculated by substituting the measured voltage value E6 into the approximation equation (8). The deviation amount Δr is given by the equation (9). Δr=[-h1+{h1 2 -4(h0-E6)*h2} 1 / 2 ] / (2*h2)…(9) Note that a lookup table corresponding to the approximation formula (9) may be stored in the storage device 32, and the deviation amount Δr may be generated by referring to the lookup table.

[0080] Moreover, the curve G1 is given by the following approximate formula (10). E1=m4*Δr 4 +m3*Δr 3 +m2*Δr 2 +m1*Δr+m0…(10) Here, m4, m3, m2, m1, and m0 are constants. The voltage value E1 is estimated as follows. First, the voltage value E6 is measured when the distance D is 6 mm. Second, the deviation Δr is calculated by substituting the voltage value E6 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 storage device 32, and the voltage value E1 may be generated by referring to the lookup table.

[0081] Next, the calibration unit 311 of the second embodiment will be described. The generation unit 312 is similar to that of the first embodiment in that it generates position data by using the calibration data 322a and the conversion data 322b, and therefore the description will be omitted. The calibration unit 311 obtains a voltage value E6 of the voltage E corresponding to the amplitude δ of the K detection signals s while maintaining the distance D between the coil La and the coil Lb at 6 mm for the K keys 12. In the calibration mode, for example, a flat plate or a jig having a thickness of 6 mm is placed between the circuit board 50 and the circuit board 60. In this state, the operator presses each of the K keys 12 in sequence, and the voltage value E6 is obtained for each detection circuit 21.

[0082] The calibration unit 311 calculates the deviation Δr by substituting the voltage value E6 into equation (6). 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). E = (E - E1) / (Ei - E1) E = E / (Ei-E1)-E1 / (Ei-E1) E = p * E + q ... (11) However, p=1 / (Ei-E1), q=-E1 / (Ei-E1)

[0083] 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 the amplitudes of K detection signals s that correspond one-to-one to the K keys 12.

[0084] In the above example, the voltage value E6 is measured by displacing the key 12 to a position where the distance D is 6 mm, but the present disclosure is not limited to this. The voltage value of the voltage E may be measured by displacing the key 12 to a predetermined position within the movable range.

[0085] FIG. 19 is a graph showing the slope of the voltage E versus the distance D. The slope is normalized to a value between 0 and 1. As shown in FIG. 19, the slope of the voltage E is maximum when the distance D is 5 mm. The greater the slope of the voltage E, the greater the sensitivity of the voltage E to the distance D. Therefore, it is preferable that the predetermined position is included in a range of the movable range in which the slope (rate of change) of the voltage E versus the distance D is a value between the maximum value and -20%. Furthermore, it is more preferable that the predetermined position is the position of the key 12 where the slope of the voltage E versus the distance D is maximum.

[0086] As described above, in the keyboard instrument 100 according to the second embodiment, the calibration section 311 calibrates the correspondence data 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 when each of the K keys 12 is in a predetermined position within the movable range. Therefore, the installation error between the detection circuit 21 and the detected circuit 22 can be calibrated for each key 12.

[0087] C: Modification Specific modified embodiments added to each of the above-mentioned embodiments are exemplified below. Two or more embodiments selected from the following examples may be appropriately combined as long as they are not mutually contradictory.

[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. Also, the detected circuit 22 may be a plate-shaped conductor.

[0089] (2) In each of the above-described embodiments, a 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] In each of the above-described embodiments, the detection circuit 22 is disposed on the underside of the key 12, while 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.

[0091] The keyboard mechanism 4A includes the key 12, a connection section 180, a hammer assembly 200, and a frame 500. The frame 500 is fixed to the housing 90. The connection section 180 connects the key 12 to the frame 500 so as to be rotatable therewith. The connection section 180 includes a plate-shaped flexible member 181, a support section 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 section 183 extends from the rear end of the plate-shaped flexible member 181. The rod-shaped flexible member 185 is supported by the support section 183 and the frame 500. That is, the rod-shaped flexible member 185 is disposed between the key 12 and the frame 500. The rod-shaped flexible member 185 is elastically curved, thereby allowing the key 12 to rotate relative to the frame 500.

[0092] 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 unit 250. A shaft support unit 220 that serves as a bearing for a rotation shaft 520 of the frame 500 is disposed on the hammer main body unit 250. The shaft support unit 220 and the rotation shaft 520 of the frame 500 are in slidable contact with each other at least at three points.

[0093] 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 is placed 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 collides with the upper stopper 430. This defines the end position at which the key 12 is pressed to the maximum extent.

[0094] 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 part of the key 12 located inside the frame 500. On the other hand, the detection circuit 21 is installed on the lower surface of the base 550 provided on the inner peripheral surface of the frame 500. In the keyboard mechanism 4A, as in each of the above-mentioned embodiments, when the key 12 is located at the rest position Zr, the detection circuit 21 and the detection target circuit 22 are closest to each other. When the key 12 is located at the end position Ze, the detection circuit 21 and the detection target circuit 22 are most distant from each other. The base 550 does not displace in response to the playing action. The base 550 is an example of a fixed member. The key 12 is an example of a movable member that displaces within a movable range in response to the playing action. Note that, as shown by the dotted line in FIG. 20, the detection circuit 21 may be arranged on the base 560 provided on the housing 90, and the detection target circuit 22 may be arranged on the lower surface of the hammer main body 250. In this embodiment, when performing the same calibration as in the first embodiment, the voltage E is measured for each key 12 with the key 12 in the rest position Zr, and the voltage value E0 is estimated based on the average of the measurement results. Also, calibration may be performed not at a position in the stroke of the key, but at a position in the stroke of the hammer body 250.

[0095] [Aspect B] FIG. 21 is a schematic diagram of a configuration in which a detection system 20 (hammer sensor) 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 conjunction with the displacement of each key 12 of the keyboard 10A. Specifically, the string-striking mechanism 2A is provided with a hammer 240 that can strike the strings by rotating, and a transmission mechanism 70 (e.g., a wippen, jack, or repetition lever) that rotates the hammer 240 in conjunction with the displacement of the key 12, for each key 12. The hammer 240 rotates around a support pin 242 as a rotation axis. The hammer head 241 strikes the strings 13 by the rotation of the hammer 240. In the above configuration, the detection system 20 detects the displacement of the hammer 240. Specifically, the detected circuit 22 is installed in the hammer shank 244. On the other hand, the detection circuit 21 is installed in the support member 14. In the string striking mechanism 2A, the detection circuit 21 and the detected circuit 22 are farthest apart when the key 12 is in the rest position Zr. Moreover, the detection circuit 21 and the detected circuit 22 are closest to each other when the key 12 is in the end position Ze. Therefore, when calibrating the present detection system 20 (hammer sensor), if the same calibration as in the first embodiment is to be performed, it is sufficient to measure the output voltage E of the detection system 20 for each key 12 with the key 12 in the end position Ze, and estimate the voltage value E0 based on the average value of the measurement results.

[0096] In the above configuration, since 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 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 contact each other 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 contact each other is measured, and the voltage value E0 is estimated based on the average value of the measurement results.

[0097] [Aspect C] FIG. 22 is a schematic diagram of 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 with a foot, a frame 920 supporting the pedal 921, and an elastic body 922 biasing the pedal 921 vertically upward. 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 circuit 21 is disposed in the frame 920 located below the pedal 921. On the other hand, the detection target circuit 22 is disposed on the lower surface of the pedal 921. In the pedal mechanism 3A, the detection circuit 21 and the detection target circuit 22 are most distant from each other in a first state in which the user does not apply force to the pedal 921. Also, when the user depresses the pedal 921 to the maximum, the detection circuit 21 and the detection target circuit 22 are most close to each other.

[0098] The pedal 921 is an example of a movable member that is displaced within a movable range in response to a performance action. The frame 920 is not displaced in response to a performance action. The frame 920 is an example of a fixed member. Note that the instrument in which the pedal mechanism 3A is used is not limited to the keyboard instrument 100. For example, a pedal mechanism 3A having a similar configuration is used in any instrument, such as a percussion instrument. In addition, in this example, the detection target circuit 22 is disposed in the pedal 921, but the detection target circuit 22 may be disposed in a member connected to the pedal 921, and the detection circuit 21 may be disposed in a fixed member so as to face the detection target circuit 22. In addition, in the calibration in this aspect, when performing the same calibration as in the first embodiment, the voltage E is measured when the pedal 921 is fully depressed, and the voltage value E0 is estimated based on the measurement result. In addition, when there are multiple pedals 921, the voltage value E0 may be estimated based on the average value of the output value for each pedal 921.

[0099] Although Fig. 22 illustrates the pedal mechanism 3A of the keyboard instrument 100, a pedal mechanism used in an electric instrument such as an electric string instrument (e.g., an electric guitar) also has a similar configuration to that of Fig. 21. The pedal mechanism used in an electric instrument is an effect pedal operated by a user to adjust various sound effects such as distortion or compressor.

[0100] (3) In each of the above-mentioned embodiments, when the key 12 is in the rest position Zr, the detection circuit 21 and the detected circuit 22 are the farthest apart, and when the key 12 is in the end position Ze, the detection circuit 21 and the detected circuit 22 are the closest to each other. The present disclosure is not limited to this, and the detection circuit 21 and the detected circuit 22 may be the closest to each other when the key 12 is in the rest position Zr, and the detection circuit 21 and the detected circuit 22 may be the farthest apart when the key 12 is in the end position Ze. For example, the keyboard 10B shown in FIG. 23 may be used instead of the keyboard 10A. In the keyboard 10B, the detected circuit 22 is disposed on the back surface of the key 12, farther from the end portion 121 than the support member 14. On the other hand, the detection circuit 21 is disposed on the support member 14 so as to face the detected circuit 22.

[0101] In this embodiment, the relationship between the distance D and the position Z of the key 12 is reversed from that in the first embodiment. That is, within the movable range of the key 12, the position Z of the key 12 at which the distance D is smallest is the end position Ze. Therefore, when performing a calibration similar to that in the first embodiment, the voltage E is measured for each key 12 with the key 12 in the rest position Zr, and the voltage value E0 is estimated based on the average value of the measurement results. The relationship between the distance D and the voltage E shown in FIG. 11B is shown in the graph in FIG. 24. The relationship between the position Z and the normalized voltage shown in FIG. 12 is shown in the graph in FIG. 25. The relationship between the voltage E and the normalized voltage shown in FIG. 14 is shown in the graph in FIG. 26.

[0102] In addition, in some of the modified examples described below, the detection circuit 21 and the detected circuit 22 are closest when the key 12 or a member interlocking with the key 12 (e.g., a hammer) are in the rest position, and the detection circuit 21 and the detected circuit 22 are farthest apart when the key 12 is in the end position Ze, so the calibration operation of this modified example will be followed. Specific examples in which the distance D and the position of the movable member are reversed are given below.

[0103] [Aspect D] FIG. 27 is a schematic diagram of a configuration in which the detection system 20 is applied to a string-striking mechanism 2B of a keyboard instrument 100. The string-striking mechanism 2B is an action mechanism that strikes the strings 13 in conjunction with the displacement of each key 12 of the keyboard 10. Specifically, the string-striking mechanism 2B is provided with 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 conjunction with the displacement of the key 12, for each key 12. The hammer 240 rotates around a support pin 242 as a rotation axis. The hammer head 241 strikes the strings 13 by the rotation of the hammer 240. In the above configuration, the detection system 20 detects the displacement of the hammer 240. Specifically, the detected circuit 22 is installed, for example, in the hammer shank 244. On the other hand, the detection circuit 21 is installed in the support member 14. In the string striking mechanism 2B, when the key 12 is in the rest position Zr, the detection circuit 21 and the detected circuit 22 are closest to each other. When the key 12 is in the end position Ze, the detection circuit 21 and the detected circuit 22 are farthest apart. The support member 14 is, for example, a structure that supports the string striking mechanism 2B. The hammer 240 is an example of a movable member that is displaced within a movable range in response to a playing action. The support member 14 is not displaced in response to a playing action. The support member 14 is an example of a fixed member. In addition, the string striking mechanism 2B is provided for each key 12. Therefore, the keyboard instrument 100 includes K hammers 240 that correspond one-to-one to the K keys 12. Therefore, when calibrating the present detection system 20 (hammer sensor), if the same calibration as in the first embodiment is performed, the output voltage E of the detection system 20 is measured for each hammer 240 in the first state in which the key 12 is in the end position Ze, and the voltage value E0 is estimated based on the average value of the measurement results.

[0104] [Aspect E] 28 is a schematic diagram of a configuration in which the detection system 20 is applied to a pedal mechanism 3B of a keyboard instrument 100. The pedal mechanism 3B is configured similarly to the pedal mechanism 3A shown in FIG. 22, except for the arrangement of the detection circuit 21 and the detected circuit 22. In the pedal mechanism 3B, the detection circuit 22 is disposed on the upper surface of the pedal 921. On the other hand, the detection circuit 21 is mounted on a frame 920 provided above the pedal 921 so as to face the detection circuit 22. In the pedal mechanism 3B, the detection circuit 21 and the detection circuit 22 are closest to each other in a first state in which the user does not apply force to the pedal 921. Moreover, when the user depresses the pedal 921 to the maximum, the detection circuit 21 and the detection circuit 22 are furthest apart.

[0105] In the calibration of this aspect, when performing the same calibration as in the first embodiment, the voltage E is measured in a first state in which the user does not apply force to the pedal 921, and the voltage value E0 is estimated based on the measurement result. In addition, when there are multiple pedals 921, the voltage value E0 is estimated based on the average value of the output values ​​of each pedal 921.

[0106] In addition, while the above-described embodiments have been described with reference to 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 the above examples. For example, the detection system 20 may detect an operator operated by a user when playing a wind instrument such as a woodwind instrument (e.g., a clarinet or a saxophone) or a brass instrument (e.g., a trumpet or a trombone).

[0107] 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 operators such as the key 12 or pedal 921 that are directly operated by the user, as well as structures such as the hammer 240 that displace in conjunction with the operation of the performance operator. 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 generates the displacement.

[0108] (4) In the above embodiment, an example is given in which the variation of the detection signal s output from the detection circuit 21 is calibrated, but the signal output by the conversion unit 312b may be used to calibrate other characteristics from the detection signal s to obtain the signal. For example, the signal may be used to calibrate generation characteristics for generating position data from the distance D.

[0109] (5) In each of the above-described embodiments, the keyboard instrument 100 includes the sound source circuit 34. However, in a configuration in which the keyboard instrument 100 includes a sound generating mechanism such as the string striking mechanism 2A or 2B, the sound source circuit 34 may be omitted. The detection system 20 is used to record the performance of the keyboard instrument 100.

[0110] As can be understood from the above description, the present disclosure is also specified as a device (operation device) that controls musical tones by outputting operation signals corresponding to performance actions to the sound source circuit 34 or the sound generation mechanism. In addition to musical instruments (keyboard instruments 100) equipped with a sound source circuit 34 or a sound generation mechanism as exemplified in each of the above-mentioned embodiments, the concept of an operation device includes devices that do not have a sound source circuit 34 or a sound generation mechanism (for example, a MIDI controller or the above-mentioned pedal mechanism 3A). In other words, the performance operation device in the present disclosure is comprehensively expressed as a device that a performer (operator) operates for performance.

[0111] D: Notes From the above-described exemplary embodiments, the following configurations can be understood, for example.

[0112] A musical instrument according to one aspect (aspect 1) of the present disclosure includes a fixed member, a movable member displaced relative to the fixed member within a movable range in response to a playing action, a detected circuit installed on the movable member and having a magnetic material or a conductor, a detection circuit having a coil arranged on the fixed member and outputting a detection signal whose voltage corresponds to the distance between the detected circuit and the coil, a generation unit that generates position data indicating the position of the movable member corresponding to the voltage of the detection signal output from the detection circuit based on a correspondence relationship between the voltage of the detection signal and the position of the movable member, and a calibration unit that calibrates the correspondence based on the value of the voltage when the position of the movable member is a predetermined position within the movable range. This aspect has the advantage that calibration can be performed after the movable member is incorporated into the musical instrument.

[0113] In a musical instrument according to one aspect (aspect 2) of the present disclosure, the predetermined position is preferably a position where the distance between the detected circuit and the coil is the smallest within the movable range. The position of the movable member where the distance is the smallest within the movable range and the position of the movable member where the distance is the largest within the movable range are easy to position the movable member. Furthermore, the position of the movable member where the distance is the smallest within the movable range has a high sensitivity of the amplitude of the detection signal to the relative positional deviation between the detection circuit and the non-detection circuit. Therefore, the accuracy of the calibration is improved by calibrating the correspondence based on the voltage corresponding to the amplitude of the detection signal when the movable member is positioned so that the distance is the smallest.

[0114] In a musical instrument according to one aspect (aspect 3) of the present disclosure, the predetermined position is included in a range within the movable range in which the slope of the voltage with respect to the distance between the detected circuit and the coil is a value ranging from the maximum value to -20%. The greater the slope of the voltage, the greater the sensitivity of the voltage to the distance. Therefore, when the predetermined position is included in a range within the movable range in which the slope (rate of change) of the voltage E with respect to the distance is a value ranging from the maximum value to -20%, the accuracy of the calibration is improved compared to when the predetermined position is not included in the range.

[0115] In a musical instrument according to one aspect (aspect 4) of the present disclosure, the calibration unit estimates the value of the voltage when the movable member is in a reference position based on the value of the voltage when the movable member is in the predetermined position, and calibrates the correspondence based on the estimated voltage, and the reference position is preferably closer to the coil than a position of the movable member where the distance between the detected circuit and the coil is the smallest within the movable range. The sensitivity of the amplitude of the detection signal to the relative positional deviation between the detection circuit and the non-detection circuit is higher when the reference position is closer to the coil than the position of the movable member where the distance is the smallest. Therefore, by calibrating the correspondence based on the estimated voltage, the accuracy of the calibration is improved.

[0116] 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 more) movable members displaced within a movable range in response to the playing action, the detected circuit is one of K detected circuits in one-to-one correspondence with the K movable members, the K detected circuits are installed on the K movable members in one-to-one correspondence, the detection circuit is one of the K detection circuits in one-to-one correspondence with the K detected circuits, and the calibration unit preferably calibrates the correspondence for each of the K movable members based on the voltages of K detection signals output from the K detection circuits when each of the K movable members is at the predetermined position within the movable range. According to this aspect, the correspondence is calibrated for each movable member, improving the accuracy of calibration for the entire musical instrument.

[0117] In a musical instrument according to one aspect (aspect 6) of the present disclosure, the movable member is one of K (K is an integer of 2 or more) 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, 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 value of the voltages for K detection signals output from the K detection circuits when each of the K movable members is at the predetermined position within the movable range, and calibrates the correspondence based on the calculated average value. According to this aspect, there is no need to calibrate the correspondences individually, thereby reducing the processing load.

[0118] In a musical instrument according to one aspect (aspect 7) of the present disclosure, the calibration unit estimates the voltage of the detection signal when the movable member is in a reference position based on the average value, and calibrates the correspondence based on the estimated voltage of the detection signal, and it is preferable that the reference position is a position of the movable member closer to the coil than a position within the movable range where the distance between the detected circuit and the coil is the smallest.

[0119] In a musical instrument according to one aspect (aspect 8) of the present disclosure, the K movable members are preferably K keys. According to this aspect, it is possible to calibrate variations in the mounting positions of the K keys.

[0120] In a musical instrument according to one aspect (aspect 8) 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. [Explanation of symbols]

[0121] 100...keyboard instrument, 10...key, 12...key, 121...end, 122...mounting 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...storage 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 within a movable range in response to a user's operation; A detection member is provided on the movable member; a detection circuit disposed on the fixed member and outputting a detection signal having a value corresponding to a position of the movable member within the movable range; a generating unit that generates position data indicating a position of the movable member according to the value of the detection signal based on a correspondence relationship between the value of the detection signal and the position of the movable member; a calibration unit that calibrates the correspondence relationship based on a value of the detection signal when the movable member is at a predetermined position within the movable range and a value of the detection signal in a state in which the movable member is not present; An operation position output device comprising:

2. A detection member is provided on a movable member that is displaced within a movable range in response to a user's operation; a detection circuit for detecting the displacement of the detection target member, the detection circuit being a magnetic induction type detection circuit that outputs a detection signal having a value corresponding to the position of the detection target member within the movable range; a calibration unit that calibrates a correspondence relationship between the value of the detection signal and the position of the detection target member based on a value of the detection signal when the position of the detection target member is a predetermined position within a displacement range and a value of the detection signal in a state where the detection target member is not present; An operation position output device comprising:

3. the detection circuit includes a coil; 3. The operation position output device according to claim 1, wherein the predetermined position is a position within the movable range where a distance between the detected member and the coil is minimum.

4. the movable member is one of K (K is an integer equal to or greater than 2) movable members that are displaced within a movable range in response to an operation by the user, the detection member is one of K detection members that correspond one-to-one to the K movable members, The K detection members are provided on the K movable members in one-to-one correspondence, the detection circuit is one of the K detection circuits that correspond one-to-one to the K detection members, the calibration unit calibrates the correspondence relationship for each of the K movable members based on values ​​of K detection signals output from the K detection circuits when each of the K movable members is at the predetermined position within the movable range.

3. The operation position output device according to claim 1 or 2.

5. the movable member is one of K (K is an integer equal to or greater than 2) movable members that are displaced within a movable range in response to an operation by the user, the detection member is one of K detection members that correspond one-to-one to the K movable members, The K detection members are provided on the K movable members in one-to-one correspondence, the detection circuit is one of the K detection circuits that correspond one-to-one to the K detection members, the calibration unit calculates an average value of the K detection signals output from the K detection circuits when each of the K movable members is at the predetermined position within the movable range, and calibrates the correspondence relationship based on the calculated average value.

3. The operation position output device according to claim 1 or 2.

6. A fixing member; a movable member that is displaced relative to the fixed member within a movable range in response to a user's operation; A detection member is provided on the movable member; An operation position output method for an operation device comprising: a detection circuit disposed on the fixed member and outputting a detection signal having a value corresponding to a position of the movable member within the movable range; generating position data indicating a position of the movable member according to the value of the detection signal based on a correspondence relationship between the value of the detection signal and the position of the movable member; calibrating the correspondence relationship based on a value of the detection signal when the movable member is at a predetermined position within the movable range and a value of the detection signal in a state in which the movable member is not present; Operation position output method.

7. a detection member provided on a movable member that is displaced within a movable range in response to a user's operation; An operation position output method for an operation device comprising: A detection circuit for detecting the displacement of the detection member, the detection circuit being a magnetic induction type, outputting a detection signal having a value corresponding to the position of the detected member within the movable range; calibrating a correspondence relationship between the value of the detection signal and the position of the detection member based on a value of the detection signal when the position of the detection member is a predetermined position within a displacement range and a value of the detection signal in a state where the detection member is not present; An operation position output method comprising:

8. A fixing member; a movable member that is displaced relative to the fixed member within a movable range in response to a user's operation; A detection member is provided on the movable member; a detection circuit disposed on the fixed member and outputting a detection signal having a value corresponding to a position of the movable member within the movable range; A computer that outputs an operation position of an operation device including: a generating unit that generates position data indicating a position of the movable member according to the value of the detection signal based on a correspondence relationship between the value of the detection signal and the position of the movable member; and a calibration unit that calibrates the correspondence relationship based on a value of the detection signal when the movable member is at a predetermined position within the movable range and a value of the detection signal in a state in which the movable member is not present; A program that functions as a

9. A detection member is provided on a movable member that is displaced within a movable range in response to a user's operation; a detection circuit for detecting the displacement of the detection target member, the detection circuit being a magnetic induction type detection circuit that outputs a detection signal having a value corresponding to the position of the detection target member within the movable range; A computer that outputs an operation position of an operation device including: a calibration unit that calibrates a correspondence relationship between the value of the detection signal and the position of the detected member based on a value of the detection signal when the position of the detected member is a predetermined position within a displacement range and a value of the detection signal in a state in which the detected member is not present; A program that functions as a

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