Detection system and musical instrument

Abstract

The first detection coil is arranged on the first key, and the second detection coil is arranged on the second key. The first signal generation unit includes a first drive coil facing the first detection coil, and generates a first detection signal corresponding to a distance between the first detection coil and the first drive coil. The second signal generation unit includes a second drive coil facing the second detection coil, and generates a second detection signal corresponding to the distance between the second detection coil and the second drive coil. The first drive coil includes a first drive unit in which a current flows in a first direction, and a second drive unit in which a current flows in a second direction opposite to the first direction. The second drive coil includes a third drive unit in which a current flows in the first direction, and a fourth drive unit in which a current flows in the first direction. The first detection coil includes a first portion and a second portion that generate induced currents in opposite directions to each other by electromagnetic induction of the first drive coil. The second detection coil includes a third portion and a fourth portion that generate induced currents in the same direction as each other by electromagnetic induction of the second drive coil.

Description

Technical Field

[0001] The present disclosure relates to a technology for detecting the position of a movable component. Background Art

[0002] In the past, various technologies for detecting the position of a movable part have been proposed. For example, Patent Document 1 discloses a detection system including an active resonance circuit provided in a main body of a keyboard instrument and a passive resonance circuit provided in each key. The active resonance circuit includes a coil that generates a magnetic field by supplying a periodic signal, and generates a detection signal corresponding to the distance between the coil and the coil of the passive resonance circuit.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2019 / 122867 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] In patent document 1, the magnetic field generated by the coil of the active resonant circuit corresponding to a key affects the coils of the passive resonant circuits of other keys adjacent to the key. Due to the mutual interaction between adjacent keys as described above, high-precision detection of each key may be hindered. It should be noted that although the detection of keys is illustrated in the above description, the same problem is assumed to exist in any structure in which multiple movable parts are close to each other. In view of the above situation, the purpose of one scheme of the present disclosure is to detect the positions of each of multiple movable parts with high precision.

[0008] Technical solutions for solving technical problems

[0009] In order to solve the above technical problems, a detection system of a scheme disclosed in the present invention comprises: a first detection coil, which is arranged on a first movable part; a second detection coil, which is arranged on a second movable part; a first signal generating unit, which includes a first driving coil opposite to the first detection coil, and generates a first detection signal corresponding to the distance between the first detection coil and the first driving coil; a second signal generating unit, which includes a second driving coil opposite to the second detection coil, and generates a second detection signal corresponding to the distance between the second detection coil and the second driving coil; the first driving coil includes a first driving unit for flowing current in a first direction, and a second driving unit for flowing current in a second direction opposite to the first direction, the second driving coil includes a third driving unit for flowing current in the first direction, and a fourth driving unit for flowing current in the first direction, the first detection coil includes a first part and a second part for generating induced currents in opposite directions to each other through electromagnetic induction of the first driving coil, and the second detection coil includes a third part and a fourth part for generating induced currents in the same direction to each other through electromagnetic induction of the second driving coil.

[0010] A musical instrument according to one embodiment of the present invention comprises: a first movable part and a second movable part, which move in accordance with a playing operation performed by a user; a first detection coil, which is provided on the first movable part; a second detection coil, which is provided on the second movable part; a first signal generating unit, which includes a first drive coil opposite to the first detection coil, and generates a first detection signal corresponding to the distance between the first detection coil and the first drive coil; a second signal generating unit, which includes a second drive coil opposite to the second detection coil, and generates a second detection signal corresponding to the distance between the second detection coil and the second drive coil; the first drive coil includes a first drive unit for flowing a current in a first direction, and a second drive unit for flowing a current in a second direction opposite to the first direction, the second drive coil includes a third drive unit for flowing a current in the first direction, and a fourth drive unit for flowing a current in the first direction, the first detection coil includes a first part and a second part for generating induced currents in opposite directions to each other by electromagnetic induction of the first drive coil, and the second detection coil includes a third part and a fourth part for generating induced currents in the same direction to each other by electromagnetic induction of the second drive coil. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a block diagram illustrating the configuration of a keyboard instrument in the first embodiment.

[0012] Figure 2 It is a schematic diagram illustrating the structure of a keyboard instrument.

[0013] Figure 3This is a circuit diagram of a signal generating unit and a detected unit.

[0014] Figure 4 2 is a block diagram illustrating the configuration of a driving circuit.

[0015] Figure 5 It is a flowchart of the control process.

[0016] Figure 6 It is a schematic diagram of the relationship table.

[0017] Figure 7 It is a schematic diagram of a signal generating unit and a detected unit.

[0018] Figure 8 A plan view of a first signal generating unit.

[0019] Fig. 9 yes Figure 8 Cross-sectional view along line a-a in FIG.

[0020] Fig.10 is a plan view of the second signal generating unit.

[0021] Fig.11 yes Fig.10 Cross-sectional view along line b-b in FIG.

[0022] Fig.12 It is a plan view of the first detected part.

[0023] Fig.13 yes Fig.12 Cross-sectional view of line c-c in .

[0024] Fig.14 A plan view of the second detection unit.

[0025] Fig.15 yes Fig.14 Cross-sectional view along line d-d in FIG.

[0026] Fig.16 This is a diagram for explaining the operation of the detection system.

[0027] Fig.17 It is the relationship between the key position and the signal level of the detection signal.

[0028] Fig.18 yes Fig.17 An illustration of each sample in .

[0029] Fig.19 It is the relationship between the key position and the signal level of the detection signal.

[0030] Fig. 20 yes Fig.19 An illustration of each sample in .

[0031] Fig.21 It is an explanatory diagram of the operation of the detection system in the second embodiment.

[0032] Fig. 22 It is a schematic diagram of the relationship table in the third embodiment.

[0033] Fig.23 This is a diagram for explaining the difference in position-level characteristics between the first key and the second key.

[0034] Fig.24 It is a plan view of the first detection section in the fourth embodiment.

[0035] Fig.25 It is a plan view of a second detection section in a modification of the fourth embodiment.

[0036] Fig.26 It is a schematic diagram of the string-strike mechanism in a modified example.

[0037] Fig. 27 It is a schematic diagram of a pedal mechanism in a modified example. DETAILED DESCRIPTION

[0038] A: First Implementation

[0039] Figure 1 It is a block diagram illustrating the structure of the keyboard instrument 100 of the first embodiment of the present disclosure. The keyboard instrument 100 is an electronic musical instrument having a keyboard assembly 20, a control system 30, and a sound playback system 40. It should be noted that in the following description, three axes (X-axis, Y-axis, and Z-axis) that are orthogonal to each other are assumed. The X-axis is an axis extending in the left-right direction (width direction) of the keyboard instrument 100. The Y-axis is an axis extending in the front-back direction (depth direction) of the keyboard instrument 100. That is, the XY plane is parallel to the horizontal plane. The Z-axis is an axis extending in the up-down direction (vertical direction) of the keyboard instrument 100. It should be noted that the direction of the X-axis is an example of a "specific direction".

[0040] The keyboard assembly 20 is an input device for receiving a performance operation performed by a user, and includes a keyboard 21 and a detection system 25. The keyboard 21 is composed of a plurality of keys 22 corresponding to different pitches. The plurality of keys 22 include a plurality of white keys and a plurality of black keys, and are arranged along the X direction. Each key 22 is a movable part that is formed in a strip along the Y axis and moves in the direction of the Z axis as the user performs a performance operation. The performance operation is to press or release a key. The detection system 25 detects the position P of each key 22 in the direction of the Z axis.

[0041] The control system 30 generates a sound signal V corresponding to the detection result obtained by the detection system 25. The sound signal V is a signal representing a musical sound of a pitch corresponding to the key 22 operated by the user. It should be noted that the control system 30 can be configured separately from the keyboard instrument 100. For example, a general-purpose information processing device such as a smart phone, a tablet terminal or a personal computer can be used as the control system 30.

[0042] The sound reproduction system 40 emits the musical sound represented by the sound signal V. For example, a single or multiple speakers, or headphones (earphones) worn on the user's head are used as the sound reproduction system 40. It should be noted that the sound reproduction system 40, which is separate from the keyboard instrument 100, can be connected to the keyboard instrument 100 by wire or wirelessly.

[0043] Figure 2 1 is a schematic diagram illustrating the structure of the keyboard musical instrument 100. Each key 22 of the keyboard 21 is supported on a support body 24 with a balance pin 23 as a fulcrum. The support body 24 is a structure that supports each element of the keyboard musical instrument 100. The front end of each key 22 moves in the direction of the Z axis in accordance with the performance operation performed by the user. The detection system 25 generates an observation signal Q representing the position P of each of the plurality of keys 22. The position P is, for example, the position of the surface of the front end of the key 22. The position P is expressed, for example, by the amount of movement based on the position of each key 22 in a non-operated state.

[0044] The detection system 25 includes a plurality of signal generating units 50, a plurality of detected units 60, and a driving circuit 70. The signal generating unit 50 and the detected unit 60 are provided for each key 22. Each signal generating unit 50 is provided on the supporting body 24. That is, the position of each signal generating unit 50 is fixed. The detected unit 60 corresponding to each key 22 is provided on the key 22. Specifically, the detected unit 60 is provided on the bottom surface 221 of the key 22. Therefore, the position of the detected unit 60 in the direction of the Z axis changes with the playing operation performed by the user.

[0045] The signal generating unit 50 includes a driving coil La. The detected unit 60 includes a detection coil Lb. The driving coil La and the detection coil Lb are opposed to each other with a gap in the Z direction. The distance between the signal generating unit 50 and the detected unit 60 (the distance between the driving coil La and the detection coil Lb) changes according to the position P of the key 22. In the first embodiment, a scheme in which the detected unit 60 is provided between the rear end portion of the key 22 and the balance pin 23 is illustrated. Therefore, the distance between the driving coil La and the detection coil Lb increases by the user's key pressing. The driving circuit 70 generates an observation signal Q of a signal level corresponding to the distance between the driving coil La and the detection coil Lb.

[0046] Figure 32 is a circuit diagram illustrating the electrical configuration of the signal generating unit 50 and the detected unit 60 corresponding to any key 22. The signal generating unit 50 is a resonant circuit including an input terminal T1, an output terminal T2, a resistor R, a drive coil La, a capacitor Ca1, and a capacitor Ca2. One end of the resistor R is connected to the input terminal T1, and the other end of the resistor R is connected to one end of the capacitor Ca1 and one end of the drive coil La. The other end of the drive coil La is connected to the output terminal T2 and one end of the capacitor Ca2. The other end of the capacitor Ca1 and the other end of the capacitor Ca2 are grounded (Gnd).

[0047] The detected part 60 is a resonant circuit including a detection coil Lb and a capacitor element Cb. One end of the detection coil Lb is connected to one end of the capacitor element Cb, and the other end of the detection coil Lb is connected to the other end of the capacitor element Cb. In the first embodiment, the resonant frequency of the signal generating part 50 and the resonant frequency of the detected part 60 are set to the same frequency. However, the resonant frequency of the signal generating part 50 and the resonant frequency of the detected part 60 may be different. For example, the resonant frequency of the signal generating part 50 is set to a frequency obtained by multiplying the resonant frequency of the detected part 60 by a predetermined constant.

[0048] Figure 4 : is a block diagram illustrating the specific structure of the driving circuit 70. The driving circuit 70 includes a supply circuit 71 and an output circuit 72. The supply circuit 71 supplies a driving signal W to the input terminal T1 of each signal generating unit 50. For example, the supply circuit 71 is a multiplexer that supplies the driving signal W in a time-series manner to each of the plurality of signal generating units 50 during each period of a predetermined length (hereinafter referred to as the "driving period"). The driving signal W is a signal whose signal level varies periodically. For example, a periodic signal of an arbitrary waveform such as a sine wave or a rectangular wave is used as the driving signal W. The period of the driving signal W is sufficiently short compared to the time length of the driving period during which the driving signal W is supplied to one signal generating unit 50. In addition, the frequency of the driving signal W is set to a frequency that is substantially equal to the resonant frequency of the signal generating unit 50 and the detected unit 60.

[0049] The drive signal W is supplied to the drive coil La via the input terminal T1 and the resistor element R. A magnetic field is generated in the drive coil La by the supply of the drive signal W. An induced current is generated in the detection coil Lb of the detected part 60 by the electromagnetic induction caused by the magnetic field generated by the drive coil La. That is, a magnetic field in a direction that cancels out the change in the magnetic field of the drive coil La is generated by the detection coil Lb. The magnetic field generated by the detection coil Lb changes according to the distance between the drive coil La and the detection coil Lb. Therefore, a detection signal D with an amplitude δ corresponding to the distance between the drive coil La and the detection coil Lb is output from the output terminal T2. The detection signal D is a periodic signal with the same frequency as the drive signal W. The amplitude δ of the detection signal D changes according to the position P of the key 22.

[0050] Figure 4 The output circuit 72 is a multiplexer that generates an observation signal Q by arranging the detection signal D output from each signal generating unit 50 in each driving period on the time axis. Specifically, the output circuit 72 generates the observation signal Q by rectifying (full-wave rectification or half-wave rectification) and smoothing the detection signal D output from the signal generating unit 50 in each driving period, and arranging the smoothed signal in each driving period on the time axis. As can be understood from the above description, the observation signal Q is set to a signal level corresponding to the position P of each key 22 in each driving period. Specifically, the farther the driving coil La is from the detection coil Lb, the more the signal level of the observation signal Q increases. The signal level of the observation signal Q in each driving period is equivalent to the signal level of the detection signal D generated by the signal generating unit 50 in the driving period.

[0051] Figure 2 The control system 30 analyzes the position P of each key 22 by analyzing the observation signal Q supplied from the drive circuit 70. The control system 30 is implemented by a computer system including a control device 31, a storage device 32, an A / D converter 33, and a sound source circuit 34. It should be noted that the control system 30 may be implemented by a plurality of devices that are separately configured in addition to being implemented by a single device.

[0052] The control device 31 is composed of a single or multiple processors that control various elements of the keyboard instrument 100. Specifically, the control device 31 is composed of one or more processors such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an SPU (Sound Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or an ASIC (Application Specific Integrated Circuit).

[0053] The storage device 32 is a single memory or multiple memories that store programs executed by the control device 31 and data used by the control device 31. The storage device 32 is composed of a known storage medium such as a magnetic recording medium or a semiconductor recording medium. It should be noted that the storage device 32 can also be composed of a combination of multiple storage media. In addition, a removable storage medium that can be attached to and detached from the keyboard instrument 100 or an external storage medium (such as an online storage) that can communicate with the keyboard instrument 100 can be used as the storage device 32.

[0054] The A / D converter 33 converts the observation signal Q supplied by the driving circuit 70 from an analog signal to a digital signal. The sound source circuit 34 generates a sound signal V representing the musical sound instructed by the control device 31. Specifically, the sound signal V is generated to represent the musical sound of the pitch corresponding to the key 22 whose position P changes among a plurality of pitches. The volume of the sound signal V is controlled, for example, according to the speed of the change of the position P. By supplying the sound signal V from the sound source circuit 34 to the sound reproduction system 40, the sound reproduction system 40 emits a musical sound corresponding to the performance operation performed by the user. It should be noted that the control device 31 can realize the function of the sound source circuit 34 by executing the program stored in the storage device 32. That is, the element (sound source unit) that generates the sound signal V can be any of a software sound source realized by the general control device 31 and a hardware sound source realized by a dedicated electronic circuit.

[0055] Figure 5 is a flowchart of the process (hereinafter referred to as "control process") executed by the control device 31. For example, the control process is repeated during each driving period. That is, the control process is executed for each key 22. Figure 5When the control process starts, the control device 31 determines the signal level E of each detection signal D based on the observation signal Q converted by the A / D converter 33 (S1). The signal level E in each driving period is a voltage value corresponding to the amplitude δ of the detection signal D generated by the signal generating unit 50 during the driving period. That is, the signal level E is set to a voltage value corresponding to the position P of one key 22 corresponding to the driving period.

[0056] The control device 31 determines the position P of each key 22 based on the signal level E (S2). In the analysis of the position P of each key 22, for example, Figure 6 The relationship table F is a data table in which the position P (P1, P2, ...) of each key 22 is set for each of the multiple numerical values ​​(E1, E2, ...) of the signal level E that can obtain the detection signal D (observation signal Q). The control device 31 retrieves the signal level E determined according to the observation signal Q from the relationship table F, and determines the position P corresponding to the signal level E among the multiple positions P as the position P of the key 22. It should be noted that the control device 31 can calculate the position P by applying a prescribed operation of the signal level E. As understood from the above description, the control device 31 functions as an element (position analysis unit) that determines the position of the key 22 based on the signal level E of the detection signal D.

[0057] The control device 31 controls the sound source circuit 34 according to the position P of each key 22 (S3). Specifically, the control device 31 determines whether each key 22 is pressed according to the position P of each key 22, and instructs the sound source circuit 34 to play the musical sound corresponding to the key 22 pressed by the user. The sound source circuit 34 generates a sound signal representing the musical sound instructed by the control device 31.

[0058] Figure 7 is a schematic diagram of the signal generating unit 50 and the detected unit 60. It should be noted that, Figure 7 The vertical dotted line in the middle represents the corresponding relationship between the positions of the signal generating unit 50 and the detected unit 60 (the detected unit 60 is located directly above the signal generating unit 50 ).

[0059] The plurality of keys 22 constituting the keyboard 21 are divided into first keys 22a and second keys 22b adjacent to each other. For example, the odd-numbered keys 22 among the plurality of keys 22 correspond to the first keys 22a, and the even-numbered keys 22 among the plurality of keys 22 correspond to the second keys 22b. Therefore, the first keys 22a and the second keys 22b are arranged alternately along the direction of the X-axis. The first key 22a is an example of a "first movable member", and the second key 22b is an example of a "second movable member". It should be noted that in Figure 7 In the figure, the plurality of keys 22 are illustrated in the same shape for convenience, but actually the shape of each key 22 is different between the white keys and the black keys.

[0060] The plurality of signal generating units 50 are composed of a plurality of first signal generating units 50a and a plurality of second signal generating units 50b. The first signal generating unit 50a corresponds to the first key 22a, and the second signal generating unit 50b corresponds to the second key 22b. That is, for example, among the plurality of signal generating units 50 arranged along the X-axis direction, the odd-numbered signal generating unit 50 is the first signal generating unit 50a, and the even-numbered signal generating unit 50 among the plurality of signal generating units 50 is the second signal generating unit 50b. Therefore, the first signal generating unit 50a and the second signal generating unit 50b are alternately arranged along the X-axis direction.

[0061] Figure 8 is a plan view of the first signal generating portion 50a viewed along the positive direction of the Z axis, Fig. 9 yes Figure 8 A cross-sectional view of the line a-a in FIG. Fig.10 is a plan view of the second signal generating unit 50b viewed along the positive direction of the Z axis, Fig.11 yes Fig.10 Cross-sectional view along line b-b in FIG.

[0062] like Fig. 9 and Fig.11 As shown in the example, each signal generating unit 50 (the first signal generating unit 50a and the second signal generating unit 50b) is provided on a substrate 51. The substrate 51 is, for example, a hard insulating substrate. Figure 7 As shown in the example, the substrate 51 is a plate-like member extending in the direction of the X axis over the range of the plurality of signal generating units 50. Fig. 9 and Fig.11 As shown in the example, the substrate 51 includes a first surface 511 and a second surface 512. The first surface 511 and the second surface 512 are surfaces on opposite sides to each other. The first surface 511 is a surface of the substrate 51 that is opposite to the detection unit 60, and the second surface 512 is a surface of the substrate 51 that is opposite to the support body 24. On the first surface 511, the resistor element R, the capacitor element Ca1, and the capacitor element Ca2 are mounted on each signal generating unit 50. It should be noted that the substrate 51 can be formed of a flexible insulating film.

[0063] A conductive pattern 521 is formed on the first surface 511 of the substrate 51. For example, the conductive pattern 521 is formed by patterning a conductive film covering the entire area of ​​the first surface 511. The conductive pattern 521 includes an input terminal T1, an output terminal T2, and a ground terminal Tg for each of the plurality of signal generating units 50. On the other hand, a conductive pattern 522 is formed on the second surface 512 of the substrate 51. For example, the conductive pattern 522 is formed by patterning a conductive film covering the entire area of ​​the second surface 512. The configurations of the first signal generating unit 50a and the second signal generating unit 50b are described below.

[0064] [First Signal Generating Unit 50a]

[0065] like Figure 8 and Fig. 9 As shown in the example, the first signal generating unit 50a includes a first drive coil La1 as Figure 3 The first driving coil La1 is composed of the first driving part A1 and the second driving part A2. The first driving part A1 and the second driving part A2 are arranged along the direction of the Y axis (i.e., the length direction of each key 22). Specifically, the first driving part A1 is located in the positive direction of the Y axis when viewed from the second driving part A2.

[0066] The first drive unit A1 is composed of a stack of winding units A11 and A12. The second drive unit A2 is composed of a stack of winding units A21 and A22. The winding units A11 and A21 are included in the conductive pattern 521 of the first surface 511, and are formed into a spiral shape that rotates clockwise from the inner circumference to the outer circumference when viewed in the positive direction of the Z axis. On the other hand, the winding units A12 and A22 are included in the conductive pattern 522 of the second surface 512, and are a spiral pattern that rotates counterclockwise from the inner circumference to the outer circumference when viewed in the positive direction of the Z axis. The center of the winding unit A11 and the center of the winding unit A12 are mutually conductive via the conductive hole Ha11. Similarly, the center of the winding unit A21 and the center of the winding unit A22 are mutually conductive via the conductive hole Ha12. The via holes Ha ( Ha11 , Ha12 , Ha13 , Ha14 , Ha21 , Ha22 , Ha23 , Ha24 ) are through holes formed in the substrate 51 .

[0067] The winding portion A11 is connected to the input terminal T1 via the resistor element R, and the winding portion A21 is connected to the output terminal T2. Furthermore, a capacitor element Ca1 is provided between the resistor element R and the ground terminal Tg, and a capacitor element Ca2 is provided between the output terminal T2 and the ground terminal Tg.

[0068] The first signal generating unit 50a includes a wiring 53 in the conductive pattern 521. The winding portion A12 of the first driving unit A1 is electrically connected to one end of the wiring 53 via the conductive hole Ha13, and the winding portion A22 of the second driving unit A2 is electrically connected to the other end of the wiring 53 via the conductive hole Ha14. That is, the winding portion A12 and the winding portion A22 are electrically connected via the wiring 53.

[0069] As according to Figure 8As can be understood, when the current in the first direction α1 flows through the winding portion A11, the current in the first direction α1 also flows through the winding portion A12. In addition, when the current in the first direction α1 flows through the winding portion A11, the current in the second direction α2 opposite to the first direction α1 flows through the winding portion A21 and the winding portion A22. That is, the current in the first direction α1 flows through the first drive portion A1, and the current in the second direction α2 flows through the second drive portion A2. Therefore, when the drive signal W is supplied to the first drive coil La1, as shown in FIG. Fig. 9 As shown, the first drive unit A1 and the second drive unit A2 generate magnetic fields in opposite directions. It should be noted that since the drive signal W is a signal whose signal level is periodically reversed, the first direction α1 and the second direction α2 are respectively reversed while maintaining the relationship of opposite directions.

[0070] [Second Signal Generating Unit 50b]

[0071] like Fig.10 and Fig.11 As shown in the example, the second signal generating unit 50b includes a second drive coil La2 as Figure 3 The second driving coil La is formed by the third driving part A3 and the fourth driving part A4. The third driving part A3 and the fourth driving part A4 are arranged along the direction of the Y axis (i.e., the length direction of each key 22). Specifically, from the fourth driving part A4, the third driving part A3 is located in the positive direction of the Y axis.

[0072] The third driving part A3 is constituted by stacking the winding part A31 and the winding part A32. The fourth driving part A4 is constituted by stacking the winding part A41 and the winding part A42. The winding part A31 and the winding part A41 are included in the conductive pattern 521 of the first surface 511, and are formed into a vortex shape that rotates clockwise from the inner circumference to the outer circumference when viewed in the positive direction of the Z axis. On the other hand, the winding part A32 and the winding part A42 are included in the conductive pattern 522 of the second surface 512, and are a vortex pattern that rotates counterclockwise from the inner circumference to the outer circumference when viewed in the positive direction of the Z axis. The center of the winding part A31 and the center of the winding part A32 are mutually conductive via the conductive hole Ha21. Similarly, the center of the winding part A41 and the center of the winding part A42 are mutually conductive via the conductive hole Ha22.

[0073] The winding portion A31 is connected to the input terminal T1 via the resistor element R. A capacitor element Ca1 is provided between the resistor element R and the ground terminal Tg, and a capacitor element Ca2 is provided between the output terminal T2 and the ground terminal Tg. In addition, the winding portion A41 is connected to the winding portion A32 via the conduction hole Ha23, and the winding portion A42 is connected to the output terminal T2 via the conduction hole Ha24.

[0074] As according to Fig.10 As can be understood, when the current in the first direction α1 flows through the winding portion A31, the current in the first direction α1 also flows through the winding portion A32. In addition, when the current in the first direction α1 flows through the winding portion A31, the current in the first direction α1 also flows through the winding portions A41 and A42. That is, the current in the first direction α1 flows through both the third drive portion A3 and the fourth drive portion A4. Therefore, when the drive signal W is supplied to the second drive coil La2, as shown in FIG. Fig.11 As shown, the third drive unit A3 and the fourth drive unit A4 generate magnetic fields in the same direction. Since the drive signal W is a signal whose signal level is periodically reversed, the first direction α1 and the second direction α2 are periodically reversed while maintaining the same direction.

[0075] As described above, the first signal generating unit 50a includes the first and second driving units A1 and A2 that pass current in opposite directions, and the second signal generating unit 50b includes the third and fourth driving units A3 and A4 that pass current in the same directions.

[0076] like Figure 7 As illustrated, the plurality of detected parts 60 are composed of a plurality of first detected parts 60a and a plurality of second detected parts 60b. The first detected part 60a corresponds to the first key 22a, and the second detected part 60b corresponds to the second key 22b. Specifically, the first detected part 60a is arranged on the bottom surface 221 of the first key 22a, and the second detected part 60b is arranged on the bottom surface 221 of the second key 22b. That is, the detected parts 60 with odd numbers among the plurality of detected parts 60 are the first detected parts 60a, and the detected parts 60 with even numbers among the plurality of detected parts 60 are the second detected parts 60b. Therefore, the first detected parts 60a and the second detected parts 60b are arranged alternately along the direction of the X axis. As described above, each group of the first signal generating part 50a and the first detected part 60a corresponds to the first key 22a, and each group of the second signal generating part 50b and the second detected part 60b corresponds to the second key 22b.

[0077] Fig.12 is a plan view of the first detected portion 60a viewed along the positive direction of the Z axis, Fig.13 yes Fig.12 The cross-sectional view of the c-c line in FIG. Fig.14 is a plan view of the second detected portion 60b viewed along the positive direction of the Z axis, Fig.15 yes Fig.14 Cross-sectional view along line d-d in FIG.

[0078] like Fig.13 and Fig.15As shown in the example, each detection unit 60 (the first detection unit 60a and the second detection unit 60b) is provided on a substrate 61. The substrate 61 is, for example, a hard insulating substrate. Figure 7 As shown in the example, the base material 61 is a plate-shaped member provided individually for each key 22. Fig.13 and Fig.15 As shown in the example, the substrate 61 includes a first surface 611 and a second surface 612. The first surface 611 and the second surface 612 are surfaces on opposite sides to each other. The first surface 611 is a surface of the substrate 61 that is opposite to the bottom surface 221 of the key 22, and the second surface 612 is a surface that is opposite to the signal generating unit 50. Capacitor elements Cb (Cb1, Cb2) are mounted on the second surface 612. It should be noted that the substrate 61 can be formed by a flexible insulating film.

[0079] A conductive pattern 621 is formed on the first surface 611 of the substrate 61. For example, the conductive pattern 621 is formed by patterning a conductive film covering the entire area of ​​the first surface 611. On the other hand, a conductive pattern 622 is formed on the second surface 612 of the substrate 61. For example, the conductive pattern 622 is formed by patterning a conductive film covering the entire area of ​​the second surface 612. The configurations of the first detection portion 60a and the second detection portion 60b are described below.

[0080] [First Detected Section 60a]

[0081] like Fig.12 and Fig.13 As shown in the example, the first detected portion 60a includes a first detection coil Lb1 as Figure 3 The first detection coil Lb1 is formed by the first part B1 and the second part B2. The first part B1 and the second part B2 are arranged along the direction of the Y axis (i.e., the length direction of each key 22). Specifically, the first part B1 is located in the positive direction of the Y axis when viewed from the second part B2.

[0082] The first part B1 is formed by stacking the winding part B11 and the winding part B12. The second part B2 is formed by stacking the winding part B21 and the winding part B22. The winding part B11 and the winding part B21 are included in the conductive pattern 621 of the first surface 611, which is formed into a spiral shape that rotates clockwise from the inner circumference to the outer circumference when viewed in the positive direction of the Z axis. On the other hand, the winding part B12 and the winding part B22 are included in the conductive pattern 622 of the second surface 612, which is a spiral pattern that rotates counterclockwise from the inner circumference to the outer circumference when viewed in the positive direction of the Z axis. The center of the winding part B11 and the center of the winding part B12 are mutually conductive via the conductive hole Hb11. Similarly, the center of the winding part B21 and the center of the winding part B22 are mutually conductive via the conductive hole Hb12. The via holes Hb (Hb11, Hb12, Hb21, Hb22) are through holes formed in the substrate 51. A capacitor Cb1 is provided between the winding portion B11 and the winding portion B21. The first detection coil Lb1 and the capacitor Cb1 are connected to each other to form a first resonant circuit 651. The capacitor Cb1 is an example of a "first capacitor".

[0083] As according to Fig.12 As understood, when the current in the second direction α2 flows through the winding portion B11, the current in the second direction α2 also flows through the winding portion B12. In addition, when the current in the second direction α2 flows through the winding portion B11, the current in the first direction α1 opposite to the second direction α2 flows through the winding portion B21 and the winding portion B22. That is, the current in the second direction α2 flows through the first part B1 of the first detected portion 60a, and the current in the first direction α1 flows through the second part B2. Therefore, the electromagnetic induction of the magnetic field generated by the first driving coil La1 generates an induced current in the first detection coil Lb1, and as a result, Fig.13 As illustrated, magnetic fields in opposite directions are generated in the first portion B1 and the second portion B2. However, the induced current generated in the first detection coil Lb1 is very weak.

[0084] [Second Detected Section 60b]

[0085] like Fig.14 and Fig.15 As shown in the example, the second detected portion 60b includes a second detection coil Lb2 as Figure 3 The second detection coil Lb2 is formed by the third part B3 and the fourth part B4. The third part B3 and the fourth part B4 are arranged along the direction of the Y axis (i.e., the length direction of each key 22). Specifically, the third part B3 is located in the positive direction of the Y axis when viewed from the fourth part B4.

[0086] The third part B3 is formed by stacking the winding part B31 and the winding part B32. The fourth part B4 is formed by stacking the winding part B41 and the winding part B42. The winding part B31 and the winding part B41 are included in the conductive pattern 621 of the first surface 611, and the winding part B32 and the winding part B42 are included in the conductive pattern 622 of the second surface 612. The winding part B31 and the winding part B42 are formed into a vortex shape that rotates clockwise from the inner circumference to the outer circumference when viewed in the positive direction of the Z axis. On the other hand, the winding part B32 and the winding part B41 are formed into a vortex shape that rotates counterclockwise from the inner circumference to the outer circumference when viewed in the positive direction of the Z axis. The center of the winding part B31 and the center of the winding part B32 are mutually conductive via the conductive hole Hb21. Similarly, the center of the winding part B41 and the center of the winding part B42 are mutually conductive via the conductive hole Hb22. A capacitance element Cb2 is provided between the winding portion B32 and the winding portion B42. The second detection coil Lb2 and the capacitance element Cb2 are connected to each other to form a second resonance circuit 652. The capacitance element Cb2 is an example of a "second capacitance element".

[0087] As according to Fig.14 As can be understood, when the current in the second direction α2 flows through the winding portion B31, the current in the second direction α2 also flows through the winding portion B32. In addition, when the current in the second direction α2 flows through the winding portion B31, the current in the second direction α2 also flows through the winding portion B41 and the winding portion B42. That is, the current in the second direction α2 flows through both the third portion B3 and the fourth portion B4. Therefore, the electromagnetic induction of the magnetic field generated by the second drive coil La2 generates an induced current in the second detection coil Lb2, and as a result, Fig.15 As illustrated, magnetic fields in the same direction are generated in the third portion B3 and the fourth portion B4. However, the induced current generated in the second detection coil Lb2 is very weak.

[0088] As described above, the first detection portion 60a includes the first portion B1 and the second portion B2 where currents flow in opposite directions, and the second detection portion 60b includes the third portion B3 and the fourth portion B4 where currents flow in the same direction.

[0089] like Figure 7As illustrated, the first drive portion A1 of the first drive coil La1 and the third drive portion A3 of the second drive coil La2 are adjacent to each other in the direction of the X-axis. The second drive portion A2 of the first drive coil La1 and the fourth drive portion A4 of the second drive coil La2 are adjacent to each other in the direction of the X-axis. In addition, the first portion B1 of the first detection coil Lb1 and the third portion B3 of the second detection coil Lb2 are adjacent to each other in the direction of the X-axis. The second portion B2 of the first detection coil Lb1 and the fourth portion B4 of the second detection coil Lb2 are adjacent to each other in the direction of the X-axis.

[0090] In addition, the first drive portion A1 of the first drive coil La1 and the first portion B1 of the first detection coil Lb1 are opposite to each other in the direction of the Z axis, and the second drive portion A2 of the first drive coil La1 and the second portion B2 of the first detection coil Lb1 are opposite to each other in the direction of the Z axis. In addition, the third drive portion A3 of the second drive coil La2 and the third portion B3 of the second detection coil Lb2 are opposite to each other in the direction of the Z axis, and the fourth drive portion A4 of the second drive coil La2 and the fourth portion B4 of the second detection coil Lb2 are opposite to each other in the direction of the Z axis.

[0091] In the first part B1 of the first detection coil Lb1, an induced current in the second direction α2 is generated by the electromagnetic induction of the first drive unit A1. In the second part B2 of the first detection coil Lb1, an induced current in the first direction α1 is generated by the electromagnetic induction of the second drive unit A2. That is, a magnetic field in a direction that cancels out the change in the magnetic field of the first drive coil La1 is generated by the first detection coil Lb1. The magnetic field generated by the first detection coil Lb1 changes according to the distance between the first drive coil La1 and the first detection coil Lb1. Therefore, the detection signal D of the amplitude δ corresponding to the distance between the first drive coil La1 and the first detection coil Lb1 is output from the output terminal T2 of the first signal generating unit 50a. As understood from the above description, the first signal generating unit 50a generates the detection signal D corresponding to the distance between the first drive coil La1 and the first detection coil Lb1. It should be noted that in the following description, there is a case where the detection signal D generated by the first signal generating unit 50a is particularly marked as "first detection signal D1".

[0092] In the third portion B3 of the second detection coil Lb2, an induced current in the second direction α2 is generated by the electromagnetic induction of the third drive unit A3. In the fourth portion B4 of the second detection coil Lb2, an induced current in the second direction α2 is generated by the electromagnetic induction of the fourth drive unit A4. That is, a magnetic field in a direction that cancels out the change in the magnetic field of the second drive coil La2 is generated by the second detection coil Lb2. The magnetic field generated by the second detection coil Lb2 changes according to the distance between the second drive coil La2 and the second detection coil Lb2. Therefore, a detection signal D with an amplitude δ corresponding to the distance between the second drive coil La2 and the second detection coil Lb2 is output from the output terminal T2 of the second signal generating unit 50b. As understood from the above description, the second signal generating unit 50b generates a detection signal D corresponding to the distance between the second drive coil La2 and the second detection coil Lb2. It should be noted that in the following description, there is a case where the detection signal D generated by the second signal generating unit 50b is particularly marked as "second detection signal D2".

[0093] Fig.16 : is an explanatory diagram of the operation of the detection system 25. The period during which the detection system 25 operates is divided into a plurality of drive periods G (G1, G2) corresponding to different keys 22. Each drive period G is set to a time length that is sufficiently short compared to the time required for the user to press or release a key. Each drive period G is a period for detecting the position P of one key 22 among the plurality of keys 22. That is, in each drive period G, the respective positions P of the plurality of keys 22 are detected in sequence in a time-sequential manner, and the action of detecting the position P is repeated for all the keys 22 of the keyboard 21. Specifically, the drive circuit 70 selects one key 22 corresponding to each of the plurality of drive periods G, and performs the action of supplying the drive signal W to the signal generating unit 50 corresponding to the key 22 in the selected state and the action of obtaining the detection signal D generated by the signal generating unit 50.

[0094] The plurality of driving periods G include a first driving period G1 and a second driving period G2. The first driving period G1 is a period for detecting the position P of the first key 22a, and the second driving period G2 is a period for detecting the position P of the second key 22b. The first driving period G1 and the second driving period G2 are alternately arranged on the time axis.

[0095] The drive circuit 70 supplies the drive signal W to the first signal generating unit 50a and acquires the first detection signal D1 generated by the first signal generating unit 50a during the first drive period G1. In addition, the drive circuit 70 supplies the drive signal W to the second signal generating unit 50b and acquires the second detection signal D2 generated by the second signal generating unit 50b during the second drive period G2. That is, the first signal generating unit 50a and the second signal generating unit 50b are driven in a time-series manner. The drive signal W supplied to the first signal generating unit 50a during the first drive period G1 is an example of a "first drive signal", and the drive signal W supplied to the second signal generating unit 50b during the second drive period G2 is an example of a "second drive signal".

[0096] As described above, by using the magnetic field generated by the first drive coil La1 to generate an induced current in the first detection coil Lb1, a first detection signal D1 corresponding to the distance between the first drive coil La1 and the first detection coil Lb1 is generated. Similarly, by using the magnetic field generated by the second drive coil La2 to generate an induced current in the second detection coil Lb2, a second detection signal D2 corresponding to the distance between the second drive coil La2 and the second detection coil Lb2 is generated. That is, the positions P of the plurality of keys 22 (the first key 22a and the second key 22b) can be detected.

[0097] Here, a scheme is assumed in which only the group of the first signal generating unit 50a and the first detected unit 60a is arranged corresponding to each key 22 (hereinafter referred to as the "comparative example"). Assume such a problem that in the comparative example, the magnetic field between two adjacent keys 22 in the direction of the X-axis (hereinafter referred to as "adjacent keys") interferes with each other, resulting in a decrease in the accuracy of detecting the position P of each key 22. In order to solve the above problem, a special scheme for reducing the interference of the magnetic field between adjacent keys is necessary, such as a scheme in which the resonance frequency of the signal generating unit 50 and the detected unit 60 is different between adjacent keys or a scheme in which the positions of the signal generating unit 50 and the detected unit 60 in the direction of the Y-axis are different between adjacent keys.

[0098] In contrast to the comparative example, in the first embodiment, currents in opposite directions flow through the first drive portion A1 and the second drive portion A2 of the first drive coil La1, while currents in the same direction flow through the third drive portion A3 and the fourth drive portion A4 of the second drive coil La2. In addition, currents in opposite directions flow through the first portion B1 and the second portion B2 of the first detection coil Lb1, while currents in the same direction flow through the third portion B3 and the fourth portion B4 of the second detection coil Lb2. According to the above scheme, the interference of the magnetic field between adjacent keys can be reduced, with the result that the position P of each key 22 can be detected with high precision. The effects of the first embodiment are described in detail below.

[0099] Fig.17 2 is a graph showing the result of measuring the relationship between the position P of each key 22 and the signal level E of the detection signal D. Fig.17 In the embodiment, based on the configuration in which the first signal generating unit 50a, the second signal generating unit 50b, and the detected unit 60 (the first detected unit 60a or the second detected unit 60b) are arranged, the signal level E is measured. Fig.17 The horizontal axis of corresponds to the distance between the driving coil La and the detecting coil Lb. That is, the value of the position P decreases due to the key press. Fig.18 yes Fig.17 An explanatory diagram of each sample (1 to 4) in FIG.

[0100] Sample 1 and Sample 2 are schemes in which the first detected portion 60a is moved in the direction of the Z axis while the first detected portion 60a is opposite to the first signal generating portion 50a. The second detected portion 60b is not provided. In Sample 1, the signal level E of the first detection signal D1 generated by the first signal generating portion 50a when only the drive signal W is supplied to the first signal generating portion 50a is measured. On the other hand, in Sample 2, the signal level E of the first detection signal D1 generated by the first signal generating portion 50a when the drive signal W is supplied to both the first signal generating portion 50a and the second signal generating portion 50b in parallel is measured.

[0101] Samples 3 and 4 are schemes in which the second detected portion 60b is moved in the direction of the Z axis while the second detected portion 60b is opposite to the second signal generating portion 50b. The first detected portion 60a is not provided. In Sample 3, the signal level E of the second detection signal D2 generated by the second signal generating portion 50b when only the drive signal W is supplied to the second signal generating portion 50b is measured. On the other hand, in Sample 4, the signal level E of the second detection signal D2 generated by the second signal generating portion 50b when the drive signal W is supplied to both the first signal generating portion 50a and the second signal generating portion 50b in parallel is measured.

[0102] The relationship between the position P and the signal level E is substantially the same between Sample 1 and Sample 2. That is, as can be seen from the comparison between Sample 1 and Sample 2, whether the second signal generating unit 50b is driven has no effect on the generation of the first detection signal D1 by the first signal generating unit 50a.

[0103] Now, assume a case where a magnetic field is generated in the second drive coil La2 by driving the second signal generating unit 50b. Magnetic fields in the same direction are generated in the third drive unit A3 and the fourth drive unit A4 of the second drive coil La2. The magnetic field of the second drive coil La2 reaches the first detection coil Lb1 of the first detected part 60a of the adjacent key 22. Therefore, through the electromagnetic induction caused by the magnetic field of the second drive coil La2, induced currents in the same direction are generated in the first part B1 and the second part B2 of the first detection coil Lb1. However, the first part B1 and the second part B2 are connected in such a way that currents flow in opposite directions to each other. Therefore, the induced currents between the first part B1 and the second part B2 are canceled. For the above reasons, the influence of the magnetic field of the second drive coil La2 on the first detection coil Lb1 is reduced.

[0104] In addition, the magnetic field of the second drive coil La2 also reaches the first drive coil La1 of the first signal generating unit 50a adjacent to the second drive coil La2. Therefore, through the electromagnetic induction caused by the magnetic field of the second drive coil La2, induced currents in the same direction as each other are generated in the first drive unit A1 and the second drive unit A2 of the first drive coil La1. However, the first drive unit A1 and the second drive unit A2 are connected in such a way that currents flow in opposite directions to each other. Therefore, the induced currents between the first drive unit A1 and the second drive unit A2 are canceled out. For the above reasons, the influence of the magnetic field of the second drive coil La2 on the first drive coil La1 is reduced.

[0105] For the reasons described above, as described above, the magnetic field generated by the second drive coil La2 by driving the second signal generator 50 b has no influence on the generation of the first detection signal D1 by the first drive coil La1 and the first detection coil Lb1 .

[0106] The relationship between the position P and the signal level E is substantially the same between Sample 3 and Sample 4. That is, as can be seen from the comparison between Sample 3 and Sample 4, whether the first signal generating unit 50a is driven has no effect on the generation of the second detection signal D2 by the second signal generating unit 50b.

[0107] Now, assume a case where a magnetic field is generated in the first drive coil La1 by driving the first signal generating unit 50a. Magnetic fields in opposite directions are generated in the first drive unit A1 and the second drive unit A2 of the first drive coil La1. The magnetic field of the first drive coil La1 reaches the second detection coil Lb2 of the second detected part 60b of the adjacent key 22. Therefore, through the electromagnetic induction caused by the magnetic field of the first drive coil La1, induced currents in opposite directions are generated in the third part B3 and the fourth part B4 of the second detection coil Lb2. However, the third part B3 and the fourth part B4 are connected in such a way that currents flow in the same directions as each other. Therefore, the induced currents between the third part B3 and the fourth part B4 are canceled out. For the above reasons, the influence of the magnetic field of the first drive coil La1 on the second detection coil Lb2 is reduced.

[0108] In addition, the magnetic field of the first drive coil La1 also reaches the second drive coil La2 of the second signal generating unit 50b of the adjacent key 22. Through the electromagnetic induction caused by the magnetic field of the first drive coil La1, induced currents in opposite directions are generated in the third drive unit A3 and the fourth drive unit A4 of the second drive coil La2. However, the third drive unit A3 and the fourth drive unit A4 are connected in such a way that currents flow in the same direction as each other. Therefore, the induced currents between the third drive unit A3 and the fourth drive unit A4 are offset. For the above reasons, the influence of the first signal generating unit 50a on the second drive coil La2 is reduced.

[0109] For the reasons described above, as described above, the magnetic field generated by the first drive coil La1 by driving the first signal generating unit 50a has no influence on the generation of the second detection signal D2 by the second drive coil La2 and the second detection coil Lb2.

[0110] Fig.19 is with Fig.17 Similarly, a graph showing the results of measuring the relationship between the position P of each key 22 and the signal level E of the detection signal D is shown. Fig. 20 yes Fig.19 An explanatory diagram of each sample (5 to 8) in FIG.

[0111] Samples 5 and 6 are schemes in which the second detected portion 60b is moved in the direction of the Z axis while the second detected portion 60b is opposite to the second signal generating portion 50b. The first detected portion 60a is not provided. In sample 5, the signal level E of the first detection signal D1 generated by the first signal generating portion 50a when only the drive signal W is supplied to the first signal generating portion 50a is measured. On the other hand, in sample 6, the signal level E of the first detection signal D1 generated by the first signal generating portion 50a when the drive signal W is supplied to both the first signal generating portion 50a and the second signal generating portion 50b in parallel is measured.

[0112] Samples 7 and 8 are schemes in which the first detected portion 60a is moved in the direction of the Z axis while the first detected portion 60a is opposite to the first signal generating portion 50a. The second detected portion 60b is not provided. In Sample 7, the signal level E of the second detection signal D2 generated by the second signal generating portion 50b when only the drive signal W is supplied to the second signal generating portion 50b is measured. On the other hand, in Sample 8, the signal level E of the second detection signal D2 generated by the second signal generating portion 50b when the drive signal W is supplied to both the first signal generating portion 50a and the second signal generating portion 50b in parallel is measured.

[0113] As can be understood from the comparison between Sample 5 and Sample 6, the position P of the second detected portion 60b has no influence on the generation of the first detection signal D1 by the first signal generating portion 50a, in addition to whether the second signal generating portion 50b is driven. In addition, as can be understood from the comparison between Sample 7 and Sample 8, the position P of the first detected portion 60a has no influence on the generation of the second detection signal D2 by the second signal generating portion 50b, in addition to whether the first signal generating portion 50a is driven.

[0114] As described above, according to the first embodiment, the influence of the magnetic field between the group of the first drive coil La1 and the first detection coil Lb1 (hereinafter referred to as the "first coil group") and the group of the second drive coil La2 and the second detection coil Lb2 (hereinafter referred to as the "second coil group") is reduced. Therefore, even in a structure where the first key 22a and the second key 22b are close to each other, a detection signal D that reflects the respective positions P of the first key 22a and the second key 22b with high accuracy can be generated.

[0115] According to the first embodiment as described above, since the influence of the magnetic field between the first coil group and the second coil group is reduced, the structure that makes the resonance frequency of the signal generating unit 50 and the detected unit 60 different between adjacent keys, or the structure that makes the positions of the signal generating unit 50 and the detected unit 60 in the direction of the Y axis different between adjacent keys can be omitted in the first embodiment. Having said that, the above structure can also be adopted in the first embodiment. In addition, the influence of the magnetic field between the first coil group and the second coil group is reduced, which means that the magnetic field generated by the first drive coil La1 and the second drive coil La2 can be enhanced compared with the comparative example. Therefore, a wide range of positions P can be detected for the first key 22a and the second key 22b respectively.

[0116] B: Second Implementation

[0117] Note that, in each of the following embodiments, elements having the same functions as those of the first embodiment are assigned the same reference numerals as those in the first embodiment, and detailed descriptions thereof are appropriately omitted.

[0118] As reference Fig.16 As described above, in the first embodiment, each of the plurality of signal generating units 50 is sequentially driven during each driving period G. However, as described above, since the influence of the magnetic field between the first coil group and the second coil group is reduced, even if the first coil group and the second coil group work in parallel with each other, the position P of each key 22 can be measured with high accuracy. In view of the above, in the second embodiment, the supply of the drive signal W to the first signal generating unit 50a and the supply of the drive signal W to the second signal generating unit 50b are performed in parallel with each other.

[0119] Fig.21 2 is an explanatory diagram of the operation of the detection system 25 in the second embodiment. The drive circuit 70 of the second embodiment drives the first signal generating unit 50a and the second signal generating unit 50b corresponding to two keys 22 (the first key 22a and the second key 22b) adjacent to each other in parallel. That is, the drive circuit 70 performs the supply of the drive signal W to the first signal generating unit 50a and the supply of the drive signal W to the second signal generating unit 50b in parallel during each drive period G. In addition, the drive circuit 70 performs the reception of the first detection signal D1 generated by the first signal generating unit 50a and the reception of the second detection signal D2 generated by the second signal generating unit 50b in parallel during each drive period G.

[0120] The process of determining the position P of each key 22 based on the signal level E of the detection signal D generated by each signal generating unit 50 is the same as that of the first embodiment. The above process is repeated for different groups of the first signal generating unit 50a and the second signal generating unit 50b, thereby determining the position P of each of the plurality of keys 22. It should be noted that the drive signal W supplied by G to the first signal generating unit 50a during the drive period is an example of a "first drive signal", and the drive signal W supplied by G to the second signal generating unit 50b during the drive period is an example of a "second drive signal".

[0121] The second embodiment can also achieve the same effect as the first embodiment. In addition, in the second embodiment, the first signal generating unit 50a and the second signal generating unit 50b are driven in parallel. Therefore, compared with the first embodiment in which the first signal generating unit 50a and the second signal generating unit 50b are driven in different driving periods G (G1, G2), it is easier to ensure the time length of the driving period G.

[0122] On the other hand, in the first embodiment, the first signal generating unit 50a and the second signal generating unit 50b are driven during different driving periods G (G1, G2). Therefore, compared with the second embodiment in which the first signal generating unit 50a and the second signal generating unit 50b are driven in parallel, the influence of the magnetic field between the first coil group and the second coil group can be more reliably reduced.

[0123] C: Third embodiment

[0124] In the first embodiment, the position P of the key 22 is determined based on the signal level E of the detection signal D using the relationship table F. However, as in Fig.17 As can be understood, the relationship between the position P of the first key 22a and the signal level E of the first detection signal D1 (sample 1 and sample 2) may be different from the relationship between the position P of the second key 22b and the signal level E of the second detection signal D2 (sample 3 and sample 4). In view of the above, in the third embodiment, (1) the relationship between the signal level E of the first detection signal D1 and the position P of the first key 22a determined by the control device 31 (position analysis unit) based on the signal level E is different from (2) the relationship between the signal level E of the second detection signal D2 and the position P of the second key 22b determined by the control device 31 (position analysis unit) based on the signal level E.

[0125] Fig. 22 Schematic diagram of the relationship table F (F1, F2) used by the control device 31 to determine the position P of each key 22 (S2). The storage device 32 of the third embodiment stores the relationship table F1 and the relationship table F2.

[0126] The relationship table F1 is used to determine the position P of the first key 22a according to the first detection signal D1 generated by the signal generating unit 50a. Specifically, the relationship table F1 is a data table in which the position P (P11, P12, ...) of each first key 22a is set for each of the multiple values ​​(E11, E12, ...) that can be obtained for the signal level E of the first detection signal D1.

[0127] On the other hand, the relationship table F2 is used to determine the position P of the second key 22b based on the second detection signal D2 generated by the second signal generating unit 50b. Specifically, the relationship table F2 is a data table in which the position P (P21, P22, ...) of each second key 22b is set for each of the plurality of numerical values ​​(E21, E22, ...) that can be obtained for the signal level E of the second detection signal D2.

[0128] The position P corresponding to a value of the signal level E is different between the relationship table F1 and the relationship table F2. Fig.17As can be understood, the signal level E of the first detection signal D1 when the first key 22a is located at the determined position P is higher than the signal level E of the second detection signal D2 when the second key 22b is located at the position P. In consideration of the above difference, the value of the position P corresponding to the determined signal level E in the relationship table F1 is higher than the value of the position P corresponding to the signal level E in the relationship table F2.

[0129] The control device 31 (position analysis unit) determines the position P of the first key 22a based on the signal level E of the first detection signal D1 using the relationship table F1, and determines the position P of the second key 22b based on the signal level E of the second detection signal D2 using the relationship table F2. The configuration and operation other than the determination of the position P are the same as those of the first embodiment.

[0130] The third embodiment can also achieve the same effect as the first embodiment. In addition, in the third embodiment, the relationship between the signal level E of the first detection signal D1 and the position P of the first key 22a is different from the relationship between the signal level of the second detection signal D2 and the second key 22b. Therefore, in a scheme where the signal level E of the first detection signal D1 and the signal level E of the second detection signal D2 are different when the first key 22a and the second key 22b are located at the same position P, the respective positions P of the first key 22a and the second key 22b can be determined with high accuracy.

[0131] D: Fourth embodiment

[0132] Fig.23 2 is a graph showing the relationship between the position P of each key 22 and the signal level E of the detection signal D (hereinafter referred to as "position-level characteristic"). Fig.23 In FIG. 1 , the position-level characteristic of the first key 22 a and the position-level characteristic of the second key 22 b are described together.

[0133] Fig.23 The position Pa is the position P of the key 22 when the driving coil La and the detecting coil Lb are closest to each other. That is, the position Pa is the position P of the key 22 when the key is pressed to the lower end of the range in which it can be displaced. Fig.23 The position Pb is the position P of the key 22 in the state where the driving coil La and the detection coil Lb are most separated. That is, the position Pb is the position P of the key 22 in the released state. As can be understood from the above description, Fig.23 The horizontal axis can also be called the distance between the driving coil La and the detecting coil Lb.

[0134] As in Fig.23 China-Israel Curve Figure 1As shown in the example, by adjusting the conditions of the drive coil La and the detection coil Lb, the signal levels E of the positions Pa and Pb can be made consistent between the first key 22a and the second key 22b. The conditions of the drive coil La and the detection coil Lb include, for example, the number of coil turns, line width, outer size, or radial spacing.

[0135] By making the conditions of the first drive coil La1 and the conditions of the second drive coil La2 different, or making the conditions of the first detection coil Lb1 and the conditions of the second detection coil Lb2 different, the signal levels E of the positions Pa and Pb are made consistent between the first key 22a and the second key 22b. Specifically, the conditions of the drive coil La and the detection coil Lb are determined so that the inductance of the first drive coil La1 and the inductance of the second drive coil La2 are actually consistent, and the inductance of the first detection coil Lb1 and the inductance of the second detection coil Lb2 are actually consistent.

[0136] However, as per Fig.23 The curve Figure 1 As understood, if only the conditions of the drive coil La and the detection coil Lb are adjusted, the position-level characteristics between the position Pa and the position Pb may be different between the first key 22a and the second key 22b. The fourth embodiment is a scheme for reducing the difference in the position-level characteristics described above.

[0137] Fig.24 6 is a plan view of the first detected portion 60a in the fourth embodiment. The first resonant circuit 651 of the first detected portion 60a in the fourth embodiment includes a resistor Rb1 in addition to the first detection coil Lb1 and capacitor Cb1 as in the first embodiment. The resistor Rb1 is an example of a “first resistor”.

[0138] The resistor element Rb1 is a chip resistor connected to the first detection coil Lb1. The resistor element Rb1 is connected in series with the first detection coil Lb1 and the capacitor element Cb1. The resistor element Rb1 and the capacitor element Cb1 are provided together on the second surface 612 of the substrate 61 (see Fig.13 ).

[0139] In the above structure, the position-level characteristic of the first key 22a changes according to the resistance value of the resistor element Rb1. Specifically, the position-level characteristic in the range between the position Pa and the position Pb changes according to the resistance value of the resistor element Rb1. Fig.23 China-Israel Figure 2As shown in the example, the resistance value of the resistor element Rb1 is determined so that the position-level characteristics in the range between the position Pa and the position Pb are close (ideally the same) between the first key 22a and the second key 22b. Specifically, the resistance value of the resistor element Rb1 is lower than the resistance value of the resistance component (DC resistance) attached to the first detection coil Lb1.

[0140] The fourth embodiment can also achieve the same effect as the first embodiment. In addition, in the fourth embodiment, since the first detection coil Lb1 of the first detected portion 60a is connected to the resistor element Rb1, as described above, the position-level characteristics of the entire range between the position Pa and the position Pb can be sufficiently close (ideally consistent) between the first key 22a and the second key 22b. It should be noted that although the fourth embodiment exemplifies a solution based on the first embodiment, the structure of the second embodiment or the third embodiment can also be applied to the fourth embodiment.

[0141] Although the above description exemplifies the scheme of adding the resistor element Rb1 to the first detection portion 60a, Fig.25 As illustrated, it is also possible to assume that a resistor element Rb2 is added to the second detection unit 60b. The resistor element Rb2 is connected in series with the second detection coil Lb2 and the capacitor element Cb2 to form a second resonance circuit 652. The resistor element Rb2 is an example of a "second resistor element".

[0142] The resistor element Rb2 is a chip resistor connected to the second detection coil Lb2 and is provided on the second surface 612 of the substrate 61 together with the capacitor element Cb2 (see Fig.15 ). The position-level characteristic of the second key 22b changes according to the resistance value of the resistor element Rb2. Therefore, the resistance value of the resistor element Rb2 is determined so that the position-level characteristic of the range between Pa and position Pb is close (ideally consistent) between the first key 22a and the second key 22b. For example, the resistance value of the resistor element Rb2 is lower than the resistance value of the resistance component (DC resistance) attached to the second detection coil Lb2. Fig.25 The same effect as that of the fourth embodiment can be achieved in this manner.

[0143] It should be noted that it is assumed that there is also a structure in which both the resistor element Rb1 and the resistor element Rb2 are provided. In the structure in which both the resistor element Rb1 and the resistor element Rb2 are provided, the resistance value of the resistor element Rb1 and the resistance value of the resistor element Rb2 may be different. In addition, although the above description illustrates a scheme in which the resistor element Rb1 and the resistor element Rb2 are chip resistors, the scheme of the resistor element Rb1 and the resistor element Rb2 is not limited to the above example. For example, the resistor element Rb1 or the resistor element Rb2 may also be implemented by making the conductive pattern 621 or the conductive pattern 622 meander.

[0144] E: Deformation

[0145] Specific modifications added to the above-described embodiments are exemplified below. A plurality of configurations arbitrarily selected from the above-described embodiments and the modifications exemplified below can be appropriately combined within the scope of no contradiction.

[0146] (1) In the above embodiments, the positions P of the keys 22 of the keyboard instrument 100 are detected, but the movable member for detecting the positions P by the detection system 25 is not limited to the keys 22. Specific embodiments of the movable member are described below.

[0147] [Scheme A]

[0148] Fig.26 1 is a schematic diagram of the structure of the string striking mechanism 91 of the keyboard musical instrument 100 in which the detection system 25 is applied. The string striking mechanism 91 is an action mechanism that strikes strings (not shown) in conjunction with the movement of each key 22 of the keyboard 21, similarly to an acoustic piano. Specifically, the string striking mechanism 91 includes a hammer 911 that can strike the string by rotating, and a transmission mechanism 912 (such as a connecting handle, a top rod, or a repetition rod, etc.) that rotates the hammer 911 in conjunction with the movement of the key 22, for each key 22. In the above structure, the detection system 25 detects the position of the hammer 911. Specifically, the detected portion 60 is provided on the hammer 911 (such as a hammer handle). On the other hand, the signal generating portion 50 is provided on the supporting member 913. The supporting member 913 is, for example, a structure that supports the string striking mechanism 91. It should be noted that the detected portion 60 can be provided on a component other than the hammer 911 in the string striking mechanism 91.

[0149] [Scheme B]

[0150] Fig. 271 is a schematic diagram of the structure of the pedal mechanism 92 of the keyboard musical instrument 100 in which the detection system 25 is applied. The pedal mechanism 92 includes a pedal 921 for the user to operate with his foot, a support member 922 for supporting the pedal 921, and an elastic body 923 for applying force to the pedal 921 from above in the vertical direction. In the above structure, the detection system 25 detects the position of the pedal 921. Specifically, the detected portion 60 is provided on the bottom surface of the pedal 921. On the other hand, the signal generating portion 50 is provided on the support member 922 in a manner opposite to the detected portion 60. It should be noted that the musical instrument using the pedal mechanism 92 is not limited to the keyboard musical instrument 100. For example, the pedal mechanism 92 of the same structure can also be used in any musical instrument such as a percussion instrument.

[0151] It should be noted that although Fig. 27 The example shown in FIG. 1 is a pedal mechanism 92 of a keyboard instrument 100, but a pedal mechanism used in an electronic musical instrument such as an electric string instrument (e.g., an electric guitar) can also be used in the same manner as in FIG. Fig. 27 The pedal mechanism used in electronic musical instruments is, for example, an effect pedal operated by a user to adjust various sound effects such as distortion or compression.

[0152] In addition, although the above embodiments illustrate the structure of detecting each key 22 of the keyboard instrument 100, the object detected by the detection system 25 is not limited to the above examples. The detection system 25 can also detect the operator operated by the user when playing a wind instrument such as a woodwind instrument (such as a clarinet or saxophone) or a gold wind instrument (such as a trumpet or trombone).

[0153] As can be understood from the above examples, the object detected by the detection system 25 is generally represented as a movable part that moves with the performance operation. In addition to the performance operating parts such as the key 22 or the pedal 921 directly operated by the user, the movable parts also include structures such as the hammer 911 that moves in conjunction with the operation of the performance operating parts. However, the movable parts in the present disclosure are not limited to the parts that move with the performance operation. That is, the movable parts are generally represented as parts that can move regardless of the cause of the movement.

[0154] (2) In the above-mentioned schemes, although the drive coil La (La1, La2) is configured with two layers, it is also possible to assume a scheme in which the drive coil La is configured with a single layer or a scheme in which the drive coil La is configured with three or more layers. The detection coil Lb (Lb1, Lb2) can also be configured with a single layer or three or more layers.

[0155] (3) In the aforementioned schemes, although the drive signal W of the same waveform is supplied to the first signal generating unit 50a and the second signal generating unit 50b, the drive signal W (first drive signal) supplied to the first signal generating unit 50a and the drive signal W (second drive signal) supplied to the second signal generating unit 50b may have different conditions such as waveform, period and amplitude.

[0156] (4) In the above-mentioned schemes, although the schemes in which the structures or electrical characteristics are the same between the first signal generating unit 50a and the second signal generating unit 50b are illustrated, the structures or electrical characteristics may be different between the first signal generating unit 50a and the second signal generating unit 50b. For example, by making the electrical characteristics such as the resistance value of the resistor R different between the first signal generating unit 50a and the second signal generating unit 50b, the relationship between the position P of the first key 22a and the signal level E of the first detection signal D1 can be made close to the relationship between the position P of the second key 22b and the signal level E of the second detection signal D2. The structures or electrical characteristics of the first detected unit 60a and the second detected unit 60b may also be different.

[0157] (5) In the above-mentioned schemes, although the scheme in which the signal level E of the detection signal D decreases when a key is pressed is exemplified, the relationship between the change in the position P of each key 22 and the increase or decrease in the signal level E of the detection signal D is not limited to the above example. For example, in a scheme in which the detected portion 60 is provided between the front end of the key 22 and the balance pin 23, the distance between the drive coil La and the detection coil Lb is reduced by the user's key pressing. Therefore, the signal level E of the detection signal D increases when a key is pressed.

[0158] (6) In the above embodiments, although the keyboard musical instrument 100 is provided with the sound source circuit 34, the sound source circuit 34 may be omitted in a structure where the keyboard musical instrument 100 is provided with a sound emitting mechanism such as the striking mechanism 91. The detection system 25 is used to store the performance content of the keyboard musical instrument 100. As can be understood from the above description, the musical instrument of the present disclosure includes not only an electronic musical instrument provided with the sound source circuit 34 but also a natural musical instrument provided with a sound emitting mechanism.

[0159] In addition, the present disclosure can also be defined as a device (operating device) that outputs an operating signal corresponding to the playing operation to the sound source circuit 34 or the sound playback mechanism to control the musical sound. As shown in the above-mentioned examples, in addition to the musical instrument (keyboard instrument 100) having the sound source circuit 34 or the sound playback mechanism, the concept of the operating device includes devices that do not have the sound source circuit 34 or the sound playback mechanism (such as a MIDI controller or the aforementioned pedal mechanism 92). That is, the performance operating device (instrument playing apparatus) in the present disclosure is generally expressed as a device that the performer (operator) operates for performance.

[0160] (7) As described above, the functions of the control system 30 of the above-mentioned schemes are realized by the cooperation of a single or multiple processors constituting the control device 31 and the program stored in the storage device 32. The program exemplified above can be provided in a form contained in a computer-readable storage medium and can be installed in a computer. The storage medium is, for example, a non-transitory storage medium, and optical storage media (optical disks) such as CD-ROMs are good examples, but also include any known form of storage media such as semiconductor storage media or magnetic storage media. It should be noted that a non-transitory storage medium refers to any storage medium other than a one-time propagation signal (transitory, propagating signal), and volatile storage media are not excluded. In addition, in the structure in which the transmission device transmits the program via a communication network, the storage medium storing the program in the transmission device is equivalent to the above-mentioned non-transitory storage medium.

[0161] F: Notes

[0162] According to the above-exemplified embodiments, for example, the following configurations can be understood.

[0163] The detection system of one scheme (scheme 1) of the present disclosure comprises: a first detection coil, which is arranged on a first movable part; a second detection coil, which is arranged on a second movable part; a first signal generating unit, which includes a first driving coil opposite to the first detection coil, and generates a first detection signal corresponding to the distance between the first detection coil and the first driving coil; a second signal generating unit, which includes a second driving coil opposite to the second detection coil, and generates a second detection signal corresponding to the distance between the second detection coil and the second driving coil; the first driving coil includes a first driving unit for flowing current in a first direction, and a second driving unit for flowing current in a second direction opposite to the first direction, the second driving coil includes a third driving unit for flowing current in the first direction, and a fourth driving unit for flowing current in the first direction, the first detection coil includes a first part and a second part for generating induced currents in opposite directions to each other through electromagnetic induction of the first driving coil, and the second detection coil includes a third part and a fourth part for generating induced currents in the same direction to each other through electromagnetic induction of the second driving coil.

[0164] In the above scheme, the magnetic field generated by the first driving coil generates an induced current in the first detection coil, thereby generating a first detection signal corresponding to the distance between the first driving coil and the first detection coil. Similarly, the magnetic field generated by the second driving coil generates an induced current in the second detection coil, thereby generating a second detection signal corresponding to the distance between the second driving coil and the second detection coil. That is, the respective positions of the first movable part and the second movable part can be detected.

[0165] On the other hand, the magnetic field generated by the first drive coil cancels the induced current generated by the third drive unit and the fourth drive unit of the second drive coil. Also, the magnetic field generated by the first drive coil cancels the induced current generated by the third part and the fourth part of the second detection coil. Similarly, the magnetic field generated by the second drive coil cancels the induced current generated by the first drive unit and the second drive unit of the first drive coil. Also, the magnetic field generated by the second drive coil cancels the induced current generated by the first part and the second part of the first detection coil.

[0166] As described above, the influence of the magnetic field between the group of the first drive coil and the first detection coil (hereinafter referred to as the "first coil group") and the group of the second drive coil and the second detection coil (hereinafter referred to as the "second coil group") is reduced. Therefore, even on the basis of a structure in which the first movable part and the second movable part are close to each other, a first detection signal and a second detection signal that reflect the respective positions of the first movable part and the second movable part with high accuracy can be generated. In addition, the reduction of the influence of the magnetic field between the first coil group and the second coil group means that the magnetic field generated by the first drive coil and the second drive coil can be enhanced. Therefore, a wide range of positions can be detected for the first movable part and the second movable part, respectively.

[0167] The "(first / second) movable component" is a component that can move. For example, an operator that moves in accordance with an operation performed by a user is exemplified as a "movable component". Specifically, a component that moves in accordance with a performance operation performed by a user is an example of a "movable component". For example, in addition to a performance operator (such as a key of a keyboard instrument) directly operated by a user, a sound-producing mechanism (such as a hammer) that moves in conjunction with the performance operator is also exemplified as a "movable component".

[0168] The "first direction" and the "second direction" are opposite directions to each other. The magnetic field generated by the current in the first direction and the magnetic field generated by the current in the second direction are opposite directions to each other. The first direction and the second direction are not limited to fixed directions. That is, the first direction and the second direction can each maintain an opposite relationship to each other while, for example, periodically reversing.

[0169] In a specific example of Scheme 1 (Scheme 2), the first movable member and the second movable member are adjacent to each other in a specific direction, the first drive unit and the third drive unit are adjacent to each other in the specific direction, the second drive unit and the fourth drive unit are adjacent to each other in the specific direction, the first part and the third part are adjacent to each other in the specific direction, and the second part and the fourth part are adjacent to each other in the specific direction. In the above schemes, the respective positions of the first movable member and the second movable member adjacent to each other in a state close to each other can be determined with high accuracy.

[0170] In a specific example of Scheme 1 or Scheme 2 (Scheme 3), there is further provided a driving circuit for driving the first signal generating unit and the second signal generating unit respectively, wherein the driving circuit supplies a first driving signal to the first signal generating unit during a first driving period, and supplies a second driving signal to the second signal generating unit during a second driving period different from the first driving period. In the above scheme, the first signal generating unit and the second signal generating unit are driven during different driving periods. Therefore, compared with the scheme of driving the first signal generating unit and the second signal generating unit in parallel, the influence of the magnetic field between the first coil group and the second coil group can be more reliably reduced.

[0171] The "(first / second) drive signal" is a periodic signal that causes the drive coil to generate a magnetic field. It should be noted that the differences and similarities between the first drive signal and the second drive signal are not limited. For example, in addition to a scheme in which signals having common characteristics such as amplitude or period are used as the first drive signal and the second drive signal, a scheme in which the amplitudes are different between the first drive signal and the second drive signal is assumed.

[0172] In the specific example of Scheme 1 or Scheme 2 (Scheme 4), there is further provided a driving circuit for driving the first signal generating unit and the second signal generating unit respectively, and the driving circuit performs the supply of the first driving signal to the first signal generating unit and the supply of the second driving signal to the second signal generating unit in parallel during the driving period. In the above scheme, the first signal generating unit and the second signal generating unit are driven in parallel. Therefore, compared with the method of driving the first signal generating unit and the second signal generating unit during different driving periods, it has the advantage of being easier to ensure the time available for driving the first signal generating unit and the second signal generating unit.

[0173] In any specific example of Scheme 1 to Scheme 4 (Scheme 5), there is further provided a position analysis unit, which determines the position of the first movable component based on the signal level of the first detection signal, and determines the position of the second movable component based on the signal level of the second detection signal, and the relationship between the signal level of the first detection signal and the position of the first movable component is different from the relationship between the signal level of the second detection signal and the position of the second movable component. In the above schemes, the relationship between the signal level of the first detection signal and the position of the first movable component is different from the relationship between the signal level of the second detection signal and the position of the second movable component. Therefore, in the scheme where the signal level of the first detection signal and the signal level of the second detection signal are different when the first movable component and the second movable component are in the same position, the respective positions of the first movable component and the second movable component can be determined with high precision.

[0174] The detection system of any specific example of the first to fifth embodiments (the sixth embodiment) includes: a first resonance circuit including the first detection coil and a first capacitor; and a second resonance circuit including the second detection coil and a second capacitor.

[0175] In the above configuration, the first detection coil and the first capacitor together form a first resonance circuit, and the second detection coil and the second capacitor together form a second resonance circuit. Therefore, the positions of the first movable member and the second movable member can be determined with high accuracy.

[0176] In a specific example of Scheme 6 (Scheme 7), the first resonant circuit further includes a first resistor element connected to the first detection coil. There is a case where the relationship between the position of the first movable part and the signal level of the first detection signal (position-level characteristic) is different from the relationship between the position of the second movable part and the signal level of the second detection signal (position-level characteristic). By appropriately selecting the resistance value of the first resistor element, the position-level characteristics between the first movable part and the second movable part can be made sufficiently close (ideally consistent).

[0177] In a specific example of Scheme 6 or Scheme 7 (Scheme 8), the second resonant circuit further includes a second resistor element connected to the second detection coil. There is a case where the relationship between the position of the first movable part and the signal level of the first detection signal (position-level characteristic) is different from the relationship between the position of the second movable part and the signal level of the second detection signal (position-level characteristic). By appropriately selecting the resistance value of the second resistor element, the position-level characteristics between the first movable part and the second movable part can be made sufficiently close (ideally consistent).

[0178] A musical instrument according to one embodiment (Aspect 9) of the present disclosure includes: a first movable part and a second movable part, which move in accordance with a playing operation performed by a user; a first detection coil, which is provided on the first movable part; a second detection coil, which is provided on the second movable part; a first signal generating unit, which includes a first drive coil opposite to the first detection coil, and generates a first detection signal corresponding to the distance between the first detection coil and the first drive coil; a second signal generating unit, which includes a second drive coil opposite to the second detection coil, and generates a second detection signal corresponding to the distance between the second detection coil and the second drive coil; the first drive coil includes a first drive unit for flowing current in a first direction, and a second drive unit for flowing current in a second direction opposite to the first direction, the second drive coil includes a third drive unit for flowing current in the first direction, and a fourth drive unit for flowing current in the first direction, the first detection coil includes a first part and a second part for generating induced currents in opposite directions to each other by electromagnetic induction of the first drive coil, and the second detection coil includes a third part and a fourth part for generating induced currents in the same direction to each other by electromagnetic induction of the second drive coil.

[0179] Description of Reference Numerals

[0180] 100…keyboard instrument, 20…keyboard assembly, 21…keyboard, 22…key, 22a…first key, 22b…second key, 23…balance pin, 24…support body, 25…detection system, 30…control system, 31…control device, 32…storage device, 33…A / D converter, 34…sound source circuit, 40…playback system, 50…signal generating unit, 50a…first signal generating unit, 50b…second signal generating unit, 60…detected unit, 60a…first detected unit, 60b…second detected unit, 70…driving circuit, 71…supply circuit, 72…output circuit.

Claims

1. A detection system, It is characterized in that have: A first detection coil, which is disposed on the first movable component; a second detection coil, which is disposed on the second movable component; a first signal generating unit including a first driving coil opposite to the first detecting coil, and generating a first detection signal corresponding to a distance between the first detecting coil and the first driving coil; a second signal generating unit including a second driving coil opposite to the second detecting coil, and generating a second detection signal corresponding to the distance between the second detecting coil and the second driving coil; The first drive coil includes a first drive unit in which current flows in a first direction, and a second drive unit in which current flows in a second direction opposite to the first direction. The second driving coil includes a third driving unit for flowing current in the first direction, and a fourth driving unit for flowing current in the first direction. The first detection coil includes a first part and a second part that generate induced currents in opposite directions to each other through electromagnetic induction of the first drive coil. The second detection coil includes a third portion and a fourth portion that generate induced currents in the same direction as each other due to electromagnetic induction of the second drive coil.

2. The detection system according to claim 1, The first movable part and the second movable part are adjacent to each other in a specific direction, The first driving portion and the third driving portion are adjacent to each other in the specific direction, The second driving portion and the fourth driving portion are adjacent to each other in the specific direction, The first portion and the third portion are adjacent to each other in the specific direction, The second portion and the fourth portion are adjacent to each other in the specific direction.

3. A detection system according to claim 1 or 2, further comprising a driving circuit for driving the first signal generating unit and the second signal generating unit respectively, The driving circuit supplies a first driving signal to the first signal generating unit during a first driving period. A second drive signal is supplied to the second signal generating section in a second drive period different from the first drive period.

4. The detection system according to claim 1 or 2, further comprising a driving circuit for driving the first signal generating unit and the second signal generating unit respectively, The drive circuit performs supply of a first drive signal to the first signal generating unit and supply of a second drive signal to the second signal generating unit in parallel during a drive period.

5. The detection system according to claim 1 or 2, further comprising a position analysis unit, the position analysis unit determining the position of the first movable member based on the signal level of the first detection signal, and determining the position of the second movable member based on the signal level of the second detection signal, The relationship between the signal level of the first detection signal and the position of the first movable member is different from the relationship between the signal level of the second detection signal and the position of the second movable member.

6. The detection system according to any one of claims 1 to 5, comprising: A first resonant circuit comprising the first detection coil and a first capacitive element; The second resonant circuit includes the second detection coil and a second capacitive element.

7. The detection system according to claim 6, The first resonant circuit further includes a first resistance element connected to the first detection coil.

8. A detection system according to claim 6 or 7, It is characterized in that The second resonant circuit further includes a second resistance element connected to the second detection coil.

9. A musical instrument, It is characterized in that have: A first movable member and a second movable member, which move in accordance with a performance operation performed by a user; a first detection coil, which is disposed on the first movable component; a second detection coil, which is disposed on the second movable component; a first signal generating unit including a first driving coil opposite to the first detecting coil, and generating a first detection signal corresponding to a distance between the first detecting coil and the first driving coil; a second signal generating unit including a second driving coil opposite to the second detecting coil, and generating a second detection signal corresponding to the distance between the second detecting coil and the second driving coil; The first drive coil includes a first drive unit in which current flows in a first direction, and a second drive unit in which current flows in a second direction opposite to the first direction. The second driving coil includes a third driving unit for flowing current in the first direction, and a fourth driving unit for flowing current in the first direction. The first detection coil includes a first part and a second part that generate induced currents in opposite directions to each other through electromagnetic induction of the first drive coil. The second detection coil includes a third portion and a fourth portion that generate induced currents in the same direction as each other due to electromagnetic induction of the second drive coil.

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