Two-dimensional position sensing system

Abstract

A sensing system for detecting position and / or movement, the system comprises: at least one active resonant circuit, each having a sensing coil for emitting an RF signal, wherein each sensing coil comprises at least one set of windings centered on an axis; and a passive circuit having a target coil for receiving RF energy from each sensing coil, wherein the target coil comprises at least one set of windings centered on an axis. For each active resonant circuit, at least one of the passive circuit and the active resonant circuit is configured to output a signal according to the degree of overlap between the target coil and the sensing coil of the active resonant circuit when the active resonant circuit is driven and the axes of the target coil and the sensing coil are maintained substantially parallel, thereby indicating the relative position and / or movement of the target coil and the sensing coil. The relative position and / or movement is substantially within a relative position range comprising at least one limit. The at least one limit is: a first relative position in which the first axis of the first coil is aligned with the outermost edge of the side of the set of windings of the second coil; and / or includes a second relative position in which the first axis is aligned with the innermost edge of the side of the winding set of the second coil, and the first coil and the second coil include the target coil and the sensing coil.

Description

Technology Field

[0001] The present disclosure relates to a sensing system for detecting position and / or movement in general, an actuator comprising said sensing system, a piano keyboard in the form of said actuator, a keyboard comprising a plurality of said actuators, and a musical instrument having said actuator. Background Technology

[0002] Keyboards for electronic musical instruments typically use switches or similar contact devices to detect a single strike position of a key. The closing of a switch is used to detect a note-on event, and the opening of a switch is used to detect a note-off event. In this regard, resonant sensors, which use an inductive coil for detection, are known to have many advantages compared to purely mechanical switches and pressure sensors.

[0003] Resonant sensors for detecting key operation typically include a measuring circuit to detect the relative position and / or movement between an active resonant circuit and a passive resonant load. The driving electronics drive the active circuit to generate a radio frequency (RF) signal at the active circuit's resonant frequency. However, the output generated by the active circuit relies on energy transfer from the active circuit to the passive load via the RF signal. Such detection can enable, for example, improvements in reliability, precision, and accuracy, and / or cost reduction.

[0004] Nevertheless, there remains a need for improved measurement or detection of user contact with keys and / or new effects, such as new musical effects for pianos or other instruments. Additional and / or alternative desirable improvements include, in particular, reduced power requirements, reduced EMI emissions, higher accuracy, increased sensor output reproducibility, and / or increased sensor speed to allow, for example, faster scan speeds.

[0005] To understand the present invention, reference is made to the disclosures below. In the following, GB 2494183 A and GB 2494230 A each relate to a music effect controller having a position sensor comprising a tuned resonant circuit. GB 2569578 A, WO 2019122867 A1, GB 2570533 A, and WO 2020030912 A1 relate to a keyboard sensor system and method. GB 2576610 A relates to an electronic drum. GB 2578346 A and WO 2020030911 A1 relate to computer input devices. GB 2610369 A and WO 2022258474 A1 relate to a position or motion detection system. Prior art literature

[0006] (Patent Document 0001) GB 2494183 A(Patent Document 0002) GB 2494230 A(Patent Document 0003) GB 2569578 A(Patent Document 0004) WO 2019122867 A1(Patent Document 0005) GB 2570533 A(Patent Document 0006) WO 2020030912 A1(Patent Document 0007) GB 2576610 A(Patent Document 0008) GB 2578346 A(Patent Document 0009) WO 2020030911 A1(Patent Document 0010) GB 2610369 A(Patent Document 0011) WO 2022258474 A1 The problem to be solved

[0007] One object of the present disclosure is to provide a sensing system for detecting position and / or movement.

[0008] One objective of the present disclosure is to provide an actuator comprising the sensing system.

[0009] One object of the present disclosure is to provide a piano keyboard in the form of the actuator, a keyboard comprising a plurality of the actuators, and a musical instrument having the actuators. means of solving the problem

[0010] According to one aspect of the present disclosure, a sensing system for detecting position and / or movement is provided, the system comprises: at least one active resonant circuit, each having a sensing coil for emitting an RF signal, and each sensing coil comprising at least one set of windings around an axis; and a passive circuit having a target coil for receiving RF energy from each sensing coil, and the target coil comprising at least one set of windings around an axis. For each active resonant circuit, at least one of the passive circuit and the active resonant circuit is configured to output a signal according to the degree of overlap between the target coil and the sensing coil of the active resonant circuit when the active resonant circuit is driven and the axes of the target coil and the sensing coil are maintained substantially parallel, thereby indicating the relative position and / or movement of the target coil and the sensing coil. The relative position and / or movement is substantially within a relative position range comprising at least one limit. The at least one limit is: a first relative position in which the first axis of the first coil is aligned with the outermost edge of the side of the set of windings of the second coil; and / or includes a second relative position in which the first axis is aligned with the innermost edge of the side of the winding set of the second coil, and the first coil and the second coil include the target coil and the sensing coil.

[0011] (For the sake of completeness regarding the term 'substantially' above, it should be noted that this term may mean 'exactly' or 'approximately' in any case throughout this disclosure.)

[0012] Advantageously, in one embodiment, a change in the output signal (preferably from the active circuit) may enable lateral position and / or movement detection in addition to any axial detection when the active circuit and the passive circuit move axially forward (forward) and / or away from each other. For lateral detection, a change in position within the range may generally involve the first axis and the second axis moving to align or out of alignment, thereby changing the overlap between the coils. The overlap change may vary, for example, between cases where each side of the target and sensing coil sets is completely overlapping or not overlapping at all. In a preferred embodiment, the first axis is the axis of the target coil and is referred to as the target axis, which moves in a direction aligned with each edge of the second coil referred to as the sensing coil, in an aligned state, in a direction away from alignment, and / or out of alignment. However, in other embodiments, the first axis is the axis of the sensing coil and the second axis is the axis of the target coil. Nevertheless, the limited range on which the detection is based allows the output signal to change monotonically according to the corresponding lateral distance change between the active coil and the passive coil. These output signal variations may also vary monotonically with changes in axial spacing. In different embodiments, monotonic variations with axial and lateral movement may occur when the axial and lateral spacings change independently or simultaneously. Additionally, it should be noted that any limit of the relative position range may be physically implemented by component(s) that block the relative movement of the coils beyond the limit. Additionally, or alternatively, any limit may be implemented electronically, for example, so that output signals generated for relative positions beyond the limit are electronically suppressed and / or ignored during signal processing and are not used in any determination of position and / or movement.

[0013] Nevertheless, any one of the sets of windings among the above coils may include only a single winding. This may mean, for example, that the innermost edge and the outermost edge of the second coil are on the same winding. On the other hand, in embodiments where there is no gap when the windings of the second coil (e.g., active coil or sensing coil) are wound, the innermost edge of the set of windings may be on the axis of the coil. The axis of the first coil and / or the axis of the second coil is preferably a central axis extending through the coil, which may include one or more preferably planar sets of windings.

[0014] In preferred embodiments, the passive circuit includes a passive resonant circuit, and preferably, the passive resonant circuit has a resonant frequency substantially the same as the resonant frequency of at least one of the active resonant circuits.

[0015] In the above sensing system, the axis of the second coil may be a second axis extending preferably substantially to the center between the inner edge and the outer edge of the winding set of the second coil, and the range may include an intermediate relative position in which the first axis is aligned within the second axis.

[0016] In the above sensing system, the first axis may extend substantially through the center of the winding set of the first coil.

[0017] A sensing system may be further provided configured to provide the output signal that changes substantially monotonically according to a monotonic change in a relative position in a lateral direction substantially perpendicular to the axial direction while the first coil and the second coil face each other with a fixed relative distance in the axial direction. In this case, it is preferable that any axial position and / or movement be detected based on output signal(s) generated at different times compared with output signal(s) used for lateral detection.

[0018] A sensing system configured to provide the output signal that changes substantially monotonically according to a monotonic change in relative position in the axial direction while the first coil and the second coil have a fixed relative spacing in the lateral direction may be further provided.

[0019] A sensing system may further be provided comprising at least one measuring circuit that generates a measurement signal indicating position and / or movement, wherein the at least one measuring circuit may be configured to: generate an axial measurement signal based on the output signal changing substantially monotonically according to a monotonic change in relative position in the axial direction at a first time point; and generate a lateral measurement signal based on the output signal changing substantially monotonically according to a monotonic change in relative position in the lateral direction at a second time point. Such embodiments may provide asynchronous axial and non-axial detection. Thus, if the lateral and axial directions are referred to as the X-axis and Y-axis, respectively, the position and / or movement directions with respect to the X-axis and Y-axis may be completely independent.

[0020] In the above sensing system, the target coil and / or each sensing coil may be a planar coil comprising at least one planar spiral. In this regard, all spirals mentioned in the present disclosure may be formed as tracks on a printed circuit board (PCB). Additionally, the sensing coil and the target coil of one embodiment may comprise a plurality of planar spirals formed as tracks on each conductive layer of the PCB, wherein the formed tracks of each spiral are preferably electrically connected by at least one via penetrating one or more intervening layers of the PCB.

[0021] A sensing system comprising a sensor having at least one active resonant circuit and a passive circuit may be further provided, wherein the at least one active resonant circuit comprises a pair of said active resonant circuits, and each of said pair has a sensing coil comprising a plurality of said sets of windings, each said set comprising a helical, and the helical of each of said pair of active resonant circuits' respective sensing coils are interleaved with each other. A primary advantage of such an embodiment may be to improve or enable lateral and axial position and / or movement with respect to, for example, X and Y coordinates or vectors, which can be measured based on simultaneous output signals. Each of such measurements may be based on output signals from both of said paired active resonant circuits.

[0022] The above sensing system may be further provided, wherein the interleaved spirals of each of the sensing coils are on opposite sides of an intermediate insulating layer, such as a printed circuit board core, and on a first side of the intermediate insulating layer, the region of the spiral of the first sensing coil lies between the intermediate insulating layer and the region of the spiral of the second sensing coil, so that the regions of the spirals overlap; and on opposite sides of the intermediate insulating layer, the region of the other spiral of the first sensing coil lies between the intermediate insulating layer and the region of the other spiral of the second sensing coil, so that the regions of the spirals overlap. Preferably, each overlap is related to the entire side of the series of windings of the spirals facing each other, such that no winding of the spiral is outside the overlap region.

[0023] A sensing system may be additionally provided, said sensing system comprising a measuring circuit for indicating axial and lateral positions and / or movements, said lateral position and / or movement being relative between a target axis, which is the axis of the target coil, and a sensing axis, which is the axis of the sensing coil of the pair of active resonant circuits, said sensing axis preferably extends substantially to the center between the inner edge and the outer edge of the overlapping region of the turn sets of the interleaved spirals, said measuring circuit configured to make an indication of a certain range of relative positions of said target axis and said sensing axis, said range being within a first relative position in which the target axis is aligned with a first edge of the overlapping region; and a second relative position in which the target axis is aligned with the opposite edge of the overlapping region.

[0024] Preferably, the range includes an intermediate relative position, wherein the target axis is aligned with the sensing axis.

[0025] In the above sensing system, the measuring circuit may be configured to indicate an axial position and a lateral position based on the output signals received substantially simultaneously from each of the pair of active resonant circuits.

[0026] The sensing system may further be provided with a part configured to generate a lateral position and / or movement indicator by subtracting a measurement of the output signal from the other of the pair from a measurement of the output signal from one of the pair of active resonant circuits. The generation of such an indicator may be performed by a processor, for example, on a PCB equipped with coils, or on a computer that receives the measurements, preferably converted into a digital format.

[0027] The sensing system may additionally be provided with a part configured to generate an axial position and / or movement indicator by adding a measurement of the output signal from one of the pair of active resonant circuits to a measurement of the output signal from the other of the pair. Similar to generation involving subtraction, generation involving addition may be performed by a processor, for example, on a PCB equipped with coils or on a computer receiving the measurements (preferably converted into a digital format).

[0028] A sensing system may be further provided that is configured to generate a two-dimensional position and / or movement indicator based on the lateral indicator and the axial indicator, and configured to generate the lateral and axial indicators based on the same measurement of the output signal from the pair of active resonant circuits. The two-dimensional indicator may be, for example, a coordinate or a vector, for example, an (x,y) coordinate.

[0029] The above sensing system may be further provided, and the sensing system is configured to perform a calibration process and indicate the relative position and / or movement of the target coil and the sensing coil, and the calibration process is the output response of each of a pair of active resonant circuits It includes determining, and the determined output responses are the output responses of the first circuit among the active resonant circuits. and output response of the other second active resonant circuit Includes. Output response The determination of is at least, the axial spacing During a constant period, different lateral intervals By measuring the output signal from the active resonant circuit, the lateral response Generating; lateral spacing While constant, different axial intervals By measuring the output signal from the active resonant circuit, the lateral response Creating; Lateral sensitivity depending on Determining; and Output response according to Deciding— is a determination procedure that includes the reference signal output value at the axial interval.

[0030] Output response The above decision is to perform the above decision procedure for the other second active resonant circuit; or for The reverse response that is the twist by Based on determining, and indicating the above relative position and / or movement, Axial spacing based on Approximation of; and / or Lateral spacing based on It is performed by determining an approximation of.

[0031] The reference value D mentioned above may be a signal output value from the active resonant circuit when the passive circuit is absent or at least when the target coil is absent. Thus, D is depicted as being at the highest level of the vertical axis in FIG. 22 merely for illustrative purposes, and this level is not reached by any of the responses (65 to 68). Practically speaking, the maximum value D may never be measured when the passive circuit or target coil of the embodiment is present. Therefore, the value of D may be a value determined by measurement during assembly, that is, before the passive circuit or target coil is added to the system being assembled. Alternatively, the value of D may be a predetermined reference value and may be estimated, for example, based on experience and / or measurements regarding relevant practical implementations of the system.

[0032] However, it should be noted that a correction procedure may not be performed. Instead, default, stored, and / or preset F1(x,y) and / or F2(x,y) may be used to represent relative position and / or movement using such approximation(s) based on the sum and / or difference of F1(x,y) and / or F2(x,y).

[0033] In the above-mentioned sensing system, the relative position and / or movement is a function It may include determining the axial spacing based on.

[0034] The difference here is and the above sum is am.

[0035] A sensing system may be additionally provided that drives the pair of active resonant circuits one at a time and / or drives subsets of multiple pairs of active resonant circuits one at a time, preferably each subset being one of the pairs. This 'one at a time' driving can be performed by using a controller to control the selection and / or scanning of each active resonant circuit or subset. Such selection and / or scanning can consequently implement time-division multiplexing. This can be advantageous, for example, in reducing interference.

[0036] A sensing system may be additionally provided, the sensing system comprising conductive layers, wherein each of the pair of sensing coils has the interleaved spiral in each conductive layer, and at least one of the conductive layers has a ground loop surrounding the interleaved spiral on that layer and the pair of interleaved spirals in another conductive layer. Preferably, the conductive layers having these loops for connecting to a fixed potential, such as a ground potential, are composed of a multilayer PCB. Each group may 'surround' the interleaved spirals, at least in a plan view, for example, when viewed along a direction parallel to the axes penetrating the spirals.

[0037] The above sensing system may be further provided, wherein the interleaved spirals of the pair of active resonant circuits overlap with the interleaved spirals of another pair of active resonant circuits, preferably each of the pair includes at least one ground loop surrounding the spiral of each of the pair of sensing conductive coils, the ground loop being in a plane between any of the spirals of the pair but not including them.

[0038] In the above sensing system, the pair of active resonant circuits may have offset resonant frequencies, and / or the passive circuit preferably comprises a pair of passive resonant circuits disposed substantially in the same location, each passive resonant circuit is intended to inductively receive energy from each of the pair of active resonant circuits, and each passive resonant circuit has a resonant frequency substantially the same as the resonant frequency of each of the pair of active resonant circuits, and / or the system is configured to provide driving signals for driving each of the pair of active resonant circuits, and the driving signals may have different driving frequencies.

[0039] In the above sensing system, the active resonant circuit may include an output mute switch connected to the output line of the sensing coil; and preferably an input mute switch connected to the input line of the sensing coil, each of the mute switches is configured to apply a fixed voltage to the connected line when the active resonant circuit is not driven or is in an idle state.

[0040] Additionally, it should be noted that each active resonant circuit generally has an input line for connection to a driver. In the embodiments, a resistive element is provided on this line to prevent current flow from the driver to the active resonant circuit. However, in some embodiments, this resistive element may be shared among multiple active resonant circuits.

[0041] The above sensing system may be further provided, wherein the at least one active resonant circuit comprises a plurality of the active resonant circuits, each having an output mute switch and preferably an input mute switch, and the sensing system is configured to selectively drive one of the active resonant circuits at a time to emit an RF signal and to apply the fixed voltage by controlling at least the output mute switch of each active resonant circuit that is not driven.

[0042] In some embodiments, the sensing system comprises a measuring circuit that generates a measuring signal representing the amplitude or phase of at least one of the output signals, wherein the measuring circuit comprises a synchronous demodulation circuit that generates the measuring signal; an amplitude-sensitive demodulation circuit that generates the measuring signal; and / or a sample-and-hold circuit that outputs the measuring signal. In this case, if at least one active resonant circuit comprises a plurality of such active resonant circuits, each having an output line, the system may comprise a controllable multiplexer to selectively connect each output line of the plurality of active resonant circuits to the measuring circuit. Additionally, it should be noted that the measuring signal representing the amplitude or phase generally has a voltage level proportional to said amplitude or phase. Preferably, the sensing system comprises an analog-to-digital converter that converts all or some of the measuring signals to provide a digital active circuit output. Additionally, in addition to or alternative to the multiplexer, one embodiment may comprise an input multiplexer that selectively provides a driving signal to the active circuit, which is used, for example, in an embodiment where individual or subgroups of active circuits do not need to be driven simultaneously.

[0043] An actuator comprising a sensing system is further provided, wherein the actuator has at least one first element having a sensing coil of at least one active resonant circuit; and at least one second element having a target coil of the passive circuit, wherein the first element and the second element face each other in an axial direction, and at least one of the first element and the second element is movable at least laterally with respect to the other of the first element and the second element, the lateral direction being substantially perpendicular to the axial direction, and preferably at least one of the first element and the second element is movable in the axial direction with respect to the other of the first element and the second element.

[0044] In the above actuator, it may be further provided that the first element comprises a conductive material and there may be an electrical insulating spacer, such as an air gap, between the conductive material and at least one of the sensing coils; and the second element comprises a conductive material and there may be an electrical insulating spacer, such as an air gap, between the conductive material and at least one of the target coils.

[0045] In addition, an actuator-type piano keyboard is provided.

[0046] A keyboard comprising a plurality of actuators is further provided, preferably, the actuators each comprise a plurality of first elements having a sensing coil, and each of the plurality of first elements is movable at least laterally with respect to a common second element.

[0047] An instrument having the above actuator or keyboard is additionally provided.

[0048] According to another aspect of the present disclosure, a method for detecting position and / or movement is provided, wherein the system drives an active resonant circuit to emit an RF signal from a sensing coil of the active resonant circuit, the sensing coil comprising at least one set of windings centered on an axis; receives energy from the emitted RF signal by a target coil of a passive circuit, the target coil comprising at least one set of windings centered on an axis; outputs at least one signal from the active resonant circuit during the RF emission, each of the at least one signal being due to the resonance of the active resonant circuit; The method includes the step of determining the relative position and / or movement of the target coil and the sensing coil based on one or more signals output when the relative position of the target coil and the sensing coil is substantially within a range having at least one limit, comprising a first relative position—wherein the central axis of the target coil is aligned with the outermost winding on one side of the sensing coil—and / or a second relative position—wherein the central axis of the target coil is aligned with the innermost winding on one side of the sensing coil.

[0049] Preferred embodiments are defined in the appended dependent claims.

[0050] Any one or more of the above aspects and / or any one or more of the optional, i.e., preferred features of the preferred embodiments may be combined in any combination.

[0051] The present disclosure also provides processor control code for implementing the aspects described above, for example, in a general-purpose computer system or a digital signal processor (DSP). According to a related aspect of the present disclosure, a non-transient data carrier is provided that includes processor control code that, when executed in a processor, causes the processor to implement one or more steps of the present disclosure. The present disclosure may include a controller comprising a microprocessor, a working memory, and a program memory, which are connected to one or more components of a system. The or each processor may be implemented in any known suitable hardware, such as a microprocessor, a digital signal processing (DSP) chip, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc. The or each processor may be connected to a bus to execute instructions and process information stored in memory, for example. Effects of the invention

[0052] According to embodiments of the present disclosure, two coils are arranged in an interleaved structure, and output signals from each are added or subtracted to independently separate X-axis and Y-axis data, thereby enabling efficient detection of axial and lateral position and / or movement. Furthermore, sophisticated musical expressions such as vibrato are possible, errors can be minimized, and corrections can be made to determine accurate displacement. Brief explanation of the drawing

[0053] To aid in understanding the present disclosure and to show how the present disclosure may be practiced, reference will be made to the following accompanying drawings as an example. FIG. 1 illustrates an exemplary active tuned resonant circuit for use in embodiments. FIG. 2 illustrates an exemplary passive-tuned resonant circuit for use in embodiments. FIG. 3 illustrates an example of a simple measurement (e.g., read-out) circuit including a synchronous demodulator that can be used in embodiments. FIG. 4 illustrates an example of a simple measurement (e.g., reading) circuit including an amplitude-sensitive demodulator that can be used in embodiments. FIG. 5 illustrates an example of a simple measurement (e.g., reading) circuit including an amplitude-sensitive demodulator having a sample-and-hold function that can be used in embodiments. FIG. 6(a) shows an enlarged example of (a1) a printed circuit design for a passive tuned resonant circuit to be used in the embodiments, and (a2) a schematic diagram thereof. Figure 6(b) shows an enlarged example of a printed circuit design for an active tuned resonant circuit used in the (b1) embodiments, and (b2) shows a schematic diagram thereof. Figure 7 shows the relative Y-axis displacement of the passive resonant circuit with respect to the active resonant circuit. FIG. 8 illustrates an example of a normalized output in a sensor comprising an active tuned resonant circuit and a readout electronic circuit, wherein the passive tuned resonant circuit is displaced along the Y-axis of FIG. 7 relative to the active tuned resonant circuit. Figure 9 shows the relative X-axis displacement of the passive resonant circuit with respect to the active resonant circuit. FIG. 10 illustrates an example of a normalized output as the passive resonant circuit is displaced along the X-axis of FIG. 9 relative to the active resonant circuit in a sensor comprising an active resonant circuit and a readout electronic circuit. FIG. 11 illustrates an enlarged example of a printed circuit design for an interleaved induction coil pair of active sensor pairs used in the embodiments, and shows a schematic diagram thereof. FIG. 12 illustrates the relative X-axis and Y-axis displacements of a passive tuned resonant circuit from an active sensor pair according to embodiments. FIG. 13 illustrates an example of a normalized output from an active sensor pair as the passive tuned resonant circuit is displaced along the X-axis of FIG. 12. FIG. 14 illustrates an active tuned resonant circuit having muting transistors for use in embodiments. FIG. 15 illustrates an enlarged example of a printed circuit design for a plurality of interleaved induction coil pairs, each surrounded by grounded traces, for use in embodiments. FIG. 16 illustrates, in enlarged form, an example of a printed circuit design for a plurality of interleaved induction coil pairs, each surrounded by grounded traces, for use in embodiments, along with its schematic representation. FIG. 17 illustrates a time-division multiplexing circuit diagram of a preferred embodiment used to determine the X and Y positions of multiple sensing elements by multiplexing multiple active tuned resonant circuits according to FIG. 14. FIG. 18 illustrates a cross-sectional view of an exemplary actuator such as the actuator of FIG. 19 of a musical instrument, wherein at least the Y position of the actuator is determined using an example. FIG. 19 illustrates a plan view of an exemplary actuator, such as the actuator of FIG. 18 of a musical instrument, wherein at least the X position of the actuator is determined using an example. Figures 20 (a), (b) and (c) illustrate, in enlarged view, an example of a printed circuit design for interleaved induction coil pairs of active sensor pairs in which passive tuned resonant circuits having different lateral positions are superimposed. FIG. 21 illustrates a block diagram of an exemplary sensing system that can be implemented in any embodiment. FIG. 22 illustrates examples of lateral response outputs in a sensor comprising an active tuned resonant circuit and a readout electronic circuit, as the passive tuned resonant circuit is laterally displaced relative to the active tuned resonant circuit as in the X direction of FIG. 9, wherein the lateral responses each correspond to different axial separations. Specific details for implementing the invention

[0054] In general, FIG. 21 illustrates an exemplary sensing system that may be implemented in any embodiment, the system comprising a target (7) and a sensor (1). Preferably, the sensor (1) receives a driving signal or waveform from a driving unit (12) and outputs a signal to a measuring unit (13).

[0055] In this regard, FIGS. 1 and FIGS. 2 illustrate exemplary active and passive circuits of a resonant sensor, respectively, wherein the passive circuit acts as a load for the active circuit. At least the active circuit includes a resonant circuit (also known as a tank circuit or tuning circuit) configured to resonate at a resonant frequency (fR) and includes an induction coil. Preferably, the active circuit and the passive circuit are resonant circuits tuned to resonate at a common resonant frequency (fR). The active circuit may include a sensor in the form of a sensing element for emitting an RF signal, such as the sensing induction coil (1) of FIG. 1. The passive circuit includes a target in the form of a target element(s) comprising at least one electrical reactance element, such as a load induction coil (7). The active circuit may be excited by a driving signal from a driving unit (driving electronics) (12) to output an RF signal that is inductively coupled from the sensing element(s) to the target element(s) of the passive circuit. The driving signal generally has a frequency substantially (e.g., exactly) the same as the resonance frequency (fR) of the active circuit and / or passive circuit.

[0056] In the embodiments, the passive circuit is configured such that a change in the position (e.g., a change in proximity) of the target element (7) relative to at least one sensing element of the active circuit causes a change in the state of at least one of the active circuit and the passive circuit. Such change in state may include a change in the resonance amplitude and / or resonance frequency of the circuit, and / or a change in the quality factor of the tuning circuit of the circuit. The relative position (e.g., proximity) and / or movement (e.g., displacement, velocity, or speed) of the sensing elements of the active circuit (typically one element) and the target elements of the passive circuit (typically one element) may be detected by detecting these changes. A measuring circuit (also referred to as a 'reading electronic device' in the embodiments) may detect a change in the resonance signal output from the active circuit (and / or the signal output from the passive circuit) and provide a digital or analog indicator indicating the relative position and / or movement.

[0057] In particular, a single sensor can detect the movement and / or position of relative motion of the sensing element and the target element in different directions. In the embodiments, the different directions are substantially perpendicular, e.g., axial and non-axial (e.g., lateral). Measurements for the directions may be based on changes in the state of the active circuit and / or passive circuit generated at each different point in time. However, in some embodiments, they may be generated simultaneously as described below.

[0058] Some embodiments may include multiple active resonant circuits that transmit to shared or respective passive circuits of one or more position / movement sensors within the system. For example, this may provide active resonant circuits for each actuator, such as keys on a keyboard. Alternatively or additionally, these multiple circuits may provide redundancy for each sensor in the system, thereby improving, for example, the reliability, strength, and / or accuracy of the total measurement signal coming from the sensor of each actuator. The active circuits may be driven using a single driving circuit in common (optionally, circuits may be selectively driven using a multiplexer), and / or may use multiple circuits to share a single measurement circuit (e.g., a reading circuit).

[0059] A preferred sensor embodiment comprises, for example, an 'interleaved pair' of active resonant circuits instead of a single active circuit having a single induction coil (1) as shown in FIG. 1. Such a pair is generally referred to as an 'active sensor pair' in this disclosure. A single sensor having such a pair can simultaneously detect / sense movement and / or position in different directions (preferably axial and non-axial) with respect to the relative movement of the target element(s) of the active sensor pair and the passive circuit.

[0060] Sensors having such active sensor pairs can provide advantages when applied to actuators capable of moving in one or more directions or dimensions, such as axial (e.g., vertical, or up and / or down) as well as lateral (e.g., horizontal, lateral, or left and / or right). These sensors can enable the detection of position (e.g., proximity) and / or movement (e.g., displacement, velocity, or speed) in each direction. Such axial and non-axial detection can be referred to as two-dimensional detection.

[0061] An actuator to which the sensor embodiment can be applied may be a musical key. This sensor may enable musical effects, such as a vibrato effect, based on the detection of axial and / or non-axial movement (movement) of the key, wherein the non-axial movement may vary depending on various lateral contacts, forces, and / or pressures applied to the key by the user. For example, if the actuator is a piano (acoustic and / or electronic) key, detecting lateral movement may electronically generate a vibrato effect when a pianist applies lateral force and / or pressure to the key. This may be in addition to the general effect of causing each note to be played when the user presses the key. The vibrato effect (a subtle and roughly regular change in pitch, as is commonly seen in string instruments such as a violin) may be controlled by changes in such lateral force / pressure and / or may be an effect triggered by instantaneously detecting such lateral force / pressure. However, more generally, embodiments of multidimensional position and / or movement sensing can be applied to any operating system, whether for music or not, and can be applied to various musical and non-musical actuators, such as, for example, musical effect pedals or computer keyboards for computer games.

[0062] Regarding the aforementioned terms such as 'axial' and 'lateral,' it is emphasized merely as a precaution that these terms do not refer to a specific direction of the actuator (e.g., a keyboard). Generally, the axial direction is the direction in which the movable element of an actuator or keyboard moves; for example, when a user strikes or pushes the keyboard (directly or indirectly, using a tool such as a stick or a hammer), the gap (e.g., the shortest distance) between the movable element and the opposing (fixed or movable) element decreases. In many applications, such as piano keys or computer keys, this axial movement can generally be considered as vertical movement (up or down), and lateral movement can be considered as horizontal movement (left or right). However, in other applications, including other musical instruments such as accordions, the terms 'axial' and 'lateral' may be purely relative and may simply refer to directions substantially perpendicular to each other. To look specifically at the case of a piano, if a single key is configured to move laterally, that movement may be lateral and / or forward or backward—that is, toward or away from the body of the piano case where the pianist or strings are located—on a fixed keybed that is situated beneath the entire set of keys and acts as a fixed and opposing element for all piano keys.

[0063] In the preferred embodiment described above, which includes a pair of active sensors, the pair of active resonant circuits have interleaved sensing induction coils. This allows for the implementation of multidimensional, e.g., X-axis and Y-axis sensors. Each of the active resonant circuits having one of the interleaved coils can operate independently so that their respective position and / or movement measurement signals can preferably be acquired simultaneously. Nevertheless, the measurements obtained from the pair can be combined, for example, by a processor to provide two-dimensional (e.g., x-axis and y-axis) position and / or movement measurement results.

[0064] An exemplary actuator comprising such a multidimensional position and / or movement sensor is illustrated in FIG. 18 and FIG. 19, respectively, which corresponds to a piano keyboard-shaped actuator. The actuator preferably comprises a movable (e.g., upper) element (45) that is rotatable around a pivot at a pivot point (47). The movable element may be prevented from moving by a bias (48), such as a spring or other mechanical linkage. The actuator may further comprise a fixed (e.g., lower) element (46). (Alternatively, one or both of the element (45) and the element (46) may be movable, and, for example, the element (45) may be fixed). At least one deformable end-stop (53) may be provided to restrict the movement of each movable element. Additionally, the actuator has a position and / or movement sensor comprising an active circuit group (52) (wherein 'group' means one or more) including at least one active resonant circuit. The group preferably includes at least one pair of active sensors as described above. The sensing element(s) of the group (52) are inductively coupled to the target element(s) of the passive circuit (51), so that each active resonant circuit provides an output signal that changes as the mutual distance between the active group and the passive circuit (e.g., between the sensing element(s) of the active group and the target element(s) of the passive circuit) changes. A driving unit (driving electronics) (12) (e.g., a driving unit as shown in FIG. 21) may be connected to drive each active circuit. A measurement circuit / block (13) (e.g., a measurement unit as shown in FIG. 21) may be a reading electronics and may include measurement circuits connected to receive outputs from each active circuit and / or passive circuit.Additionally or alternatively, the measurement circuit (13) may be connected via multiplexers and / or switches to receive outputs from a plurality of active circuits and / or passive circuits, wherein the active circuit(s) belong to an active circuit group, preferably an active sensor pair. For example, a pivot centered on a point (47) allows a movable (e.g., upper) element (45) to move in at least two dimensions, which are illustrated as an X-axis and a Y-axis for example.

[0065] (It should be noted that in the embodiments described above in relation to FIGS. 18 and 19, the passive circuit (51) (target) and the active circuit group (52) may be provided to the element (45) and the element (46), respectively, or vice versa. It should also be noted that sensor embodiments, such as the sensor described above in relation to FIGS. 18 and 19, may be modified and mounted on existing actuators, for example, existing piano keys or keyboards.)

[0066] Considering the above-described active sensor pair in more detail, the paired active tuned resonant circuits may each include a capacitive element(s), such as an input capacitive element (2) and / or an output capacitive element (3); and an inductive element(s), such as a sensing inductive coil (1). One or both of the active circuits may further include an input resistive element (4). A driving unit (12) comprising one or more driving circuits may be connected to the input line (5) (e.g., a terminal or port) of each active circuit of the group / pair. The driving unit (12) may be configured to selectively enable or suppress the driving of each active circuit of one or more groups of active circuits, such as the active sensor pair. Thus, each active resonant circuit may be in an idle state or a driven state depending on a driving control signal received from the driving unit (12). The measurement circuit (13) may be connected to an output line (6) (e.g., an output terminal or port). With regard to optional features, the input resistive element (4) may be omitted, for example, but its presence may (i) limit the current supplied from the driving electronics to the active tuned resonant circuit in the embodiments and / or (b) increase the sensitivity of position and / or movement detection when the measurement circuit is connected to the active tuned resonant circuit. Such current limiting may, in turn, reduce the operating current and thus reduce the power consumption and / or electromagnetic emissions of the active tuned resonant circuit in some embodiments.

[0067] Referring to FIG. 2, the passive circuit includes a reactance in the form of an induction coil (7) and, preferably, a capacitive element (8). The induction coil (7) and the capacitive element (8) can be connected to form a closed resonant LC circuit (also called a tank circuit). This passively tuned resonant circuit has a resonant frequency ( has ).

[0068] The resonant frequency of an active tuned resonant circuit or each active tuned resonant circuit is the resonant frequency of a passive tuned resonant circuit ( It is desirable to adjust them to be close to or identical to (equal to). This is achieved by appropriately selecting the reactance values ​​of the sensing element and the target element, for example, the input capacitive element (2) and / or the output capacitive element (3) and the sensing induction coil (1). The size or inductance values ​​of the induction coils (1 and 7) do not need to be the same or similar.

[0069] The driving unit / electronic device (12) is preferably at the resonant frequency of the active circuit or each active circuit ( An oscillating voltage driving waveform can be provided having a frequency equal to or close to that of the passive circuit, preferably having a frequency equal to that of the passive circuit. This waveform may be a sine wave, a square wave, or a pulse train, and may be generated, for example, by a microcontroller timer or a digital or analog timing circuit.

[0070] When an active circuit, such as the active circuit of FIG. 1, is driven by such a driving unit / electronic device (12), the signal amplitude of the output line (6) may decrease as the distance between the active circuit (e.g., sensing induction coil (1)) and the target element (e.g., induction coil (7) of the corresponding passive circuit) decreases. The decrease in the output line signal of the active circuit may occur because more energy is coupled from the sensing element to the target element of the passive circuit (e.g., induction coil). This coupled energy may be dissipated by the passive circuit.

[0071] In embodiments where an element such as a movable element (e.g., upper element) (45) or a fixed element (e.g., lower element) (46) of an actuator comprises an electrically conductive material, an electrically insulating spacer (49 or 50) (e.g., an air gap) made of a non-conductive material may be interposed between the electrically conductive material and one or more electrically reactive elements. Such electrically reactive elements may include target elements (7) of a passive circuit (51) or sensing elements (1) of an active circuit group / pair.

[0072] A measurement circuit (13) (e.g., a reading electronic device) may have at least one measurement circuit that generates a measurement signal having a voltage proportional to the characteristics (e.g., amplitude) of a signal received from a passive circuit or an active circuit. This received signal may come from, for example, an output line (e.g., a terminal or port) (6) of an active resonant circuit shown in FIG. 1. The measurement circuit (13) may further include an analog-to-digital converter (43) that converts the measurement signal into a digital value. At least a portion of the measurement circuit (13), such as a demodulator and / or an analog-to-digital converter, may be shared among a number of active and / or passive circuits, such as one or more groups of active circuits (e.g., a pair) of active resonant circuits, using, for example, multiplexing and / or switching. The groups of passive and / or active circuits sharing the circuit (13) may correspond to respective actuators, for example, keys of a keyboard.

[0073] A component of a measurement circuit (13), for example, a read electronic device, includes a synchronous demodulation circuit. As illustrated in FIG. 3, an example of such a demodulation circuit demodulates an output signal from an output line (e.g., a read port) (6) of an active circuit through an analog switch or multiplier (32). The switch or multiplier (32) is controlled by a driving waveform received from a demodulation input line (30), wherein the phase of the driving waveform is preferably adjusted by a phase shifting element (31). Such demodulation can preferably cause a measurement signal in the form of a low-frequency (or DC) voltage to be output to a demodulation output line (36) through a low-pass filter (33).

[0074] Another configuration of the measurement circuit (13) includes an amplitude-sensitive demodulation circuit. An example of such a demodulation circuit in FIG. 4 uses a diode (26) to rectify an output signal from an output line (e.g., output or read port) (6) of an active resonant circuit. This diode forms a peak-hold circuit together with a capacitive element (34) and a resistive element (37). The peak-hold circuit outputs a measurement signal through the output line (36). The time constant of this peak-hold circuit may be determined by or depend on the capacitance of the capacitive element (34) and the resistance of the resistive element (37).

[0075] Regardless of the type of demodulator used in the measurement circuit (13), it may be advantageous to reduce the power level (absolute or relative) of some or all frequency components of the driving signal of the output line (36). It is desirable that such reduction be below a desirable maximum value or threshold level for the desired practical application of the position and / or motion detection system. The frequency components are preferably at the resonant frequency of the active circuit connected to the demodulator ( It includes components that are the same as or close to ). This can be achieved by configuring the low-pass filter (33) of FIG. 3 or the peak-hold circuit of FIG. 4 to have a time constant suitable for such level reduction. Power reduction may be advantageous in embodiments where such frequency components can cause errors in the measurement signal appearing on the output line (36). On the other hand, it is desirable that such a time constant be small enough to measure rapid changes in distance between the sensor and the target according to the desired performance criteria of the actual application. Thus, in some embodiments, the selection or determination of the demodulator time constant(s) may involve a trade-off between minimizing measurement error by reducing the level of the frequency components of the sensor drive signal and maximizing the response speed of the position and / or motion detection system measurement. In some embodiments, to reduce the measurement error to about 1%, it is desirable that the time constant be large enough to reduce the drive frequency components by about 40 dB or more.

[0076] The measurement circuit (13), for example, another configuration of the reading electronic device, includes a sample-and-hold circuit. In the exemplary sample-and-hold circuit of FIG. 5, the output signal from the output line (6) (e.g., the reading port) of the active resonant circuit is rectified by a diode (26) that forms a peak-hold circuit together with a capacitive element (34). While the switch (35) is controlled to be open, the voltage of the capacitive element (34) is maintained, and the maintained voltage can represent the measurement signal of the output line (36). When the measurement period ends, the switch (35) can be closed to discharge the capacitive element (34), and then the switch (35) is opened to start a new measurement period.

[0077] The induction coils (1 and 7) used in the active and passive circuits, respectively, may be of any type. However, a planar spiral coil in which the winding is formed by printed tracks, such as a printed circuit board (PCB), may be preferred. In the embodiments, these coils or tracks may provide one or more advantages, such as cost reduction, inductance values ​​with high reproducibility, and / or mounting other components, such as capacitive elements (2, 3, and / or 8) and / or resistive elements (4), using the PCB. Advantageously, by using these planar coils, it may be possible to provide multiple induction coils within each active and / or passive circuit with closely matched inductance values. (It should also be noted that each spiral may have any suitable shape, such as a square, circle, hexagon, or octagon).

[0078] Referring to FIG. 6(b), at least one sensing element of an exemplary active tuned resonant circuit may be formed on a PCB comprising one or more electrically conductive layers. As illustrated, the sensing element may be in the form of an induction coil (1) comprising a continuous spiral track on a first electrically conductive layer. This spiral track may be electrically connected to one or more additional spiral tracks on other conductive layers of the PCB via connecting via(s) (9) and optional connecting wire(s). This is illustrated in the lower drawing of FIG. 6(b), where lines represent various layers of the PCB and each circle represents a cross-section of a track forming the coil (1). Capacitive element(s) (2 and / or 3) and / or resistive element (4) may be mounted on the PCB and / or preferably located close to or adjacent to the spiral track(s) of the induction coil (1). Input lines (e.g., terminals or ports) (5) and / or output lines (e.g., terminals or ports) (6) of the active circuit may be provided on the PCB to be connected to the driving unit (12) and the measuring circuit (13) (e.g., a reading electronic device), respectively. The lower drawing of FIG. 6(b) described above is a simplified schematic diagram of a sensing induction coil (1) formed as a spiral track on two layers of the PCB, wherein the coil is shown in cross-section passing through the plane (11). In this example, the two spiral tracks may be on opposing outer surface layers of the PCB. However, other embodiments may include spiral track(s) on the inner and / or outer layers of a multilayer PCB.

[0079] While it may be desirable to use printed tracks on all or part of the induction coil spirals, neither this nor any use of PCBs is essential in any of the embodiments described in this disclosure. Additionally, it should be noted that in some embodiments, a coil comprising one or more wire windings may be used, for example, instead of a plurality of connected PCB track spirals.

[0080] Similarly, referring to FIG. 6(a), at least one target element of an exemplary passive circuit (preferably a tuned resonant circuit) may be formed on a PCB comprising one or more electrically conductive layers. As illustrated in the drawing, the target element in the form of an induction coil (7) may be formed as a continuous spiral track on the first electrically conductive layer. This spiral track may be electrically connected to one or more additional spiral tracks, preferably on other conductive layers of the PCB, via connecting via(s) (10) and / or connecting wire(s). This is illustrated in the lower drawing of FIG. 6(a), where lines represent various layers of the PCB and each circle represents each cross-section of the track forming the spiral of the coil (7). A capacitive element (8) may be mounted on the PCB and / or, preferably, positioned in close proximity to the spiral track(s) of the induction coil (7). The lower drawing of FIG. 6(a) described above is a simplified schematic diagram of such an induction coil (7) formed by a spiral track on two layers of a PCB as a cross-section viewed through plane (11). In this example, the two spiral tracks shown may be on opposing outer surface layers of the PCB. However, other embodiments may include spiral track(s) on the inner and / or outer layers of a multilayer PCB.

[0081] Following the above discussion on the circuit configuration of multidirectional sensors, the following discusses in more detail the change in sensor output due to changes in the axial and non-axial, preferably lateral, spacing between the sensing element and the target element.

[0082] FIG. 7 illustrates an axial spacing along the 'Y' direction, where 'Y' is used to represent the axial direction between a target element in the form of an induction coil (7) of a passive circuit (in this example, a passive tuned resonant circuit) and a sensing element in the form of an induction coil (1) of an active tuned resonant circuit. The corresponding response characteristics are illustrated in FIG. 8. Similar to FIG. 6(a) and FIG. 6(b), in FIG. 7, each induction coil (1 and 7) is illustrated as having a configuration comprising a plurality of planar helicals on each layer. However, other configurations, for example, having a single planar helical on each coil, can also achieve response characteristics similar or identical to those illustrated in FIG. 8.

[0083] (Cross-sectional views of the sensing element coil (1) and target element coil (7) of the active and passive circuits are illustrated only by way of example on the left and right sides of FIG. 7. Likewise, lines indicated by a single arrow represent exemplary Y-direction movement corresponding to a decrease in axial spacing (as indicated on the horizontal graph axis of FIG. 8), but the axial movement of the movable element may be, for example, up or down. Additionally, if both elements are axially movable toward each other and / or away from each other, such axial movement may be relative.)

[0084] More specifically, FIG. 8 illustrates exemplary response characteristics of a normalized sensor output from a measurement circuit (13) (e.g., a reading electronic device), wherein response levels are indicated on the vertical axis (or y-axis) of FIG. 8 and axial spacing is indicated on the horizontal axis (or x-axis). In the embodiments, this characteristic generally follows an S-shaped curve, and when the axial spacing between the target element in the form of an induction coil (7) and the sensing element in the form of an induction coil (1) is small, the sensor output indicates a minimum level (e.g., exactly or substantially 0). (When opposing actuator elements having a sensing element and a target element are in contact, this small spacing may be a gap thickness of substantially 0). This characteristic generally indicates a higher level (e.g., a maximum level) when the spacing between the sensing element and the target element is large. In particular, FIG. 8 has a region where the response characteristic is substantially linear between the higher / maximum level and the lower / minimum level.

[0085] On the other hand, FIG. 9 illustrates a lateral movement along the 'X' direction, where 'X' is used to indicate the lateral direction (lateral from left to right in this example, as specifically illustrated in FIG. 9) of the target element in the form of an induction coil (7) of the passive circuit (in this example, the tuned resonant circuit) to the sensing element in the form of an induction coil (1) of the active tuned resonant circuit. In this example, the winding of each coil comprises a planar helical track (e.g., circular or rectangular), and each of these tracks forms a spiral around the gap between the opposing sides of the helical track winding. Each of these gaps is illustrated in FIG. 9 between corresponding sets of filled (or unfilled) small circles representing each layered helical track wire cross-section. However, the presence of such gaps is merely desirable, and some embodiments may have track cross-sections distributed over the entire range of any spiral.

[0086] (As with FIG. 7, the depicted left-right positions of the sensing element coil (1) and passive element coil (7) of the active and passive circuits in FIG. 8 are merely examples. Likewise, each line indicated by a single arrow represents an exemplary X-direction movement corresponding to a change in lateral spacing (such spacing indicated on the horizontal graph axis of FIG. 10). However, the lateral movement of the movable elements may be forward and backward, for example, from right to left or from left to right. Additionally, if both elements can move laterally toward each other or away from each other, the lateral movement may be relative.)

[0087] FIG. 10 illustrates exemplary response characteristics of a normalized sensor output from a measurement circuit (13) (e.g., a reading electronic device) connected to an active coil as illustrated in FIG. 9. Response levels are indicated on the vertical axis (or y-axis) of FIG. 10, and off-axial / lateral spacing is indicated on the horizontal axis (or x-axis). As described above in relation to FIG. 9, in this example, each helical track has a spacing surrounded by helical windings, so the helical section has a set of winding sections on each side of the spacing. Each set has an inner edge and an outer edge, each comprising an inner winding section and an outer winding section. Here, 'inner' generally means adjacent to the spacing, and 'outer' corresponds to the outermost (most outer) winding of the helical. As further illustrated in FIG. 9, the helicals of each coil can be substantially aligned, for example, so as to be substantially symmetrical with respect to the spacing of the helicals of the coil and / or on both sides of the insulating layer in which the windings are interposed.

[0088] In relation to the exemplary coils of FIG. 9 having spacing in each coil spiral, the corresponding response of FIG. 10 shows three notable spacing values ​​X1 to X3.

[0089] In X1, the target axis extending through the gaps within the helical portions of the target induction coil (7) is aligned with the outer edge of the sensing induction coil (1), and the outer edge is the outermost edge of the set of winding sections on one side of the induction coil (1). (Preferably, the target axis is a central axis passing through the target coil, i.e., a symmetry axis, which may include, for example, preferably a cylindrical or rectangular coil formed of a plurality of planar coils.)

[0090] In X3, the target axis of the target induction coil (7) is aligned with the inner edge of the sensing induction coil (1), and the inner edge belongs to the same set of winding cross-sections as the aforementioned outer edge.

[0091] In X2, the target axis of the target induction coil (7) is aligned with the sensing axis, which is preferably the center or midpoint axis between the outer edge and the inner edge of the set of winding cross-sections of the sensing induction coil (1).

[0092] With respect to FIGS. 9 and 10, when the off-axial / lateral spacing of the coils is between or at the position of spacing X3 and X1, the response is substantially or exactly monotonic (generally always increasing), and therefore part or all of this region is desirable for detecting the lateral spacing of target and sensing elements such as the induction coil (7) and the sensing induction coil (1). However, other monotonic regions of the response characteristics may also be used, for example, part or all of the region in FIG. 10 where the sensor output decreases from a peak at spacing X1 to a minimum value, or part or all of the region where the sensor output increases from a minimum value occurring before spacing X1 as the lateral spacing increases.

[0093] Furthermore, the inventors recognized advantages when the active circuit group (52) of the position and / or movement sensor is formed as the ‘active sensor pair’ described above. As described above, such pairs each have active resonant circuits comprising interleaved sensing induction coils. Thus, the sensing induction coil (1) of the first active resonant circuit can be interleaved with the sensing induction coil (1) of the second active resonant circuit. Preferably, in the embodiment corresponding to FIGS. 9 and 10, the position and / or movement sensing is limited to the relative positional range between the active sensor pair and the target element, and this maximum range is defined as the target axis (preferably extending through the center of the target coil) being within the area where the two sensing induction coils overlap (e.g., the entire non-axial / lateral range). This range may be within or substantially coincide with the area between the intervals X1 and X3 for each sensing induction coil. Accordingly, to provide a substantially monotonous response, off-axial / lateral position and / or movement detection is preferably performed within the relative position range of an interleaved active sensor pair with respect to a target element, wherein this range extends between or within positions where each edge of the overlapping region (thus, in the embodiments, the spacing edges of each interleaved coil) is aligned with the target axis.

[0094] An actual implementation example of such an interleaved pair of sensing induction coils using a multilayer PCB is illustrated in FIG. 11. The first sensing induction coil (1A) is formed as a planar coil including a spiral winding on each conductive layer (e.g., 17 and 19) of a multilayer PCB (e.g., a PCB having four conductive layers). It is preferable that a plurality of these spiral windings on each conductive layer be connected vias as described above. The second sensing induction coil (1B) is formed as a planar coil on other conductive layers (e.g., 18 and 20) of a multilayer PCB, wherein the spiral on each conductive layer is again connected vias as described above. In the drawing, the upper conductive layer (17) of the first sensing induction coil (1A) is separated from the upper conductive layer (18) of the second sensing induction coil (1B) by at least a first insulating layer (e.g., a generally thin first prepreg layer (15)). The lower conductive layer (19) of the first sensing induction coil (1A) is separated from the lower conductive layer (20) of the second sensing induction coil (1B) by at least a second insulating layer (e.g., a generally thin second prepreg layer (16)). The upper set of layers (including at least conductive and insulating layers (15, 17, and 18) in the example of FIG. 11) is separated from the lower set of layers (including at least conductive and insulating layers (16, 19, and 20) in the example of FIG. 11) by at least one intermediate insulating layer such as a PCB core material (21).

[0095] For a substantially monotonic response in the embodiment illustrated in FIG. 11, position and / or movement detection is limited to the relative positional range of the target axis and the detection axis of the target element coil and the interleaved coil, respectively. Referring to the intervals X1 to X3 illustrated in FIG. 9 and 10, the range limits of detection using the embodiment of FIG. 11 may be defined by the edges of the overlapping region (23) of the planar coils aligned with the target axis, and these limits generally correspond to the regions between X1 and X3 illustrated in FIG. 9 and 10. The relative position of the detection axis (22), preferably at the center of the overlapping region (23) (the overlapping region is defined by the lateral range of the overlapping set of winding cross-sections of the active pair of interleaved helices), preferably aligned with the target axis may substantially correspond to the average of the position of the first interleaved detection induction coil for the X2 interval relative to the target and the position of the second detection induction coil for the X2 interval relative to the target. Additionally or alternatively, this alignment of the sensing axis and the target axis may correspond to both the X2 interval of the first sensing induction coil (1A) and the X2 interval of the second sensing induction coil (1B), and these X2 intervals may occur at the same locations on the sensing axis. Consistent with the discussion of X2 described above in relation to FIGS. 9 and 10, this sensing axis may be the average of substantially center or midpoint axes of the interleaved sensing coils, each of which lies between the inner and outer edges of the set of overlapping winding cross-sections of each interleaved spiral, such as the coils (1A or 1B) ('Upper' and 'Lower' simply refer to different sides of the PCB core and do not imply a specific direction).

[0096] To further understand the above, FIG. 20 illustrates, in one embodiment, the target and sensing coil positions for each of the X1, X2, and X3 intervals when the interleaved coils (1A and 1B) of FIG. 11 are used. It should be noted that in the examples of FIG. 20 (e.g., FIG. 20 (a), (b), and (c)), X1 (1A) is aligned with X3 (1B) because the windings overlap 100%, and thus the illustrated examples are symmetrical merely for the sake of simplification of explanation. If the degree of overlap were smaller, they would generally not be aligned.

[0097] Other embodiments of the configuration illustrated in FIG. 11 may be advantageous in one or more aspects. The inductance of the first sensing induction coil (1A) may be close to or substantially match the inductance of the second sensing induction coil (1B), for example, if the spacings between the spirals or layers of each sensing induction coil (e.g., 17 to 19 and 18 to 20 in FIG. 11) are similar. Then, the active resonant circuits of the active sensor pair can be finely tuned. Additionally or alternatively, any displacement or movement of the first sensing induction coil 1A from its position in a reference state relative to the target element may correspond to the magnitude of such any displacement of the second sensing induction coil 1B from its reference position. This reference state preferably corresponds to a state where the sensor position or movement is zero. In a reference state, at least one of the sensing coils may be located at the center within a preferably limited range of motion of the coil with respect to the target element(s) of the passive (preferably resonant) circuit, for example, preferably with respect to the center of the target axis. For example, this alignment may be improved if the thickness of the intermediate insulating layer(s), such as the PCB core (21), is significantly greater than the thickness of the insulating layer, such as the prepreg layers (15 and 16). In this way, the axial displacement (Y) can be detected more accurately by using both the first sensing induction coil (1A) and the second sensing induction coil (1B). Generally, it is desirable for the interleaved sensing coils to be manufactured as identically as possible with respect to the target element(s). For example, each insulating layer (15 and 16 in FIG. 11) separating the interleaved coils is preferably thin so that the interleaved coils have substantially the same effective distance from the target element(s) or the target axis. Similarly, as illustrated in the lower drawing of FIG. 11, it is desirable that the total thickness of the intermediate insulating layer(s) separating the spiral pairs of each sensing coil be kept as thin as possible.

[0098] An additional or alternative advantage of the interleaved configuration can be understood from FIG. 12. If the target axis (e.g., center axis) of the target induction coil (7) of the passive (preferably tuned) resonant circuit can be moved laterally or in the X direction (e.g., left and / or right) with respect to the sensing axis (22) (e.g., center line of the overlap area (23)) of the interleaved spirals of the active sensor pair of sensing induction coils, and further moved in the axial or Y direction toward or away from the interleaved spirals, then in the embodiments, a two-dimensional position and / or movement can be obtained more accurately and / or based on the simultaneous output signal. (Such movement of the target axis may be absolute or relative to the sensing axis, and in the embodiments, it may be the target element and / or interleaved spirals that are actually moving). Preferably, the overlapping or sensing area (23) is limited so that the position of the target axis of the induction coil (7) for each of the first sensing induction coil (1A) and the second sensing induction coil (1B) of the active sensor pair is within an area substantially corresponding to the interval value range X1 to X3 as shown in FIG. 9.

[0099] FIG. 13 illustrates an exemplary normalized sensor output from an active sensor pair when the passive tuned resonant circuit moves laterally in the X direction across the sensing axis (22) (e.g., the center line of the overlapping region (23) of the interleaved spirals). The position X=0 corresponds to the position of the sensing axis (22). Due to symmetry, the output (24) from the first active resonant circuit of the active sensor pair may be a substantial mirror image of the output (25) from the second active resonant circuit of the active sensor pair. Meanwhile, when the passive tuned resonant circuit moves axially in the Y direction as illustrated in the exemplary response of FIG. 12, the outputs from the two active resonant circuits of the active sensor pair will be modulated, for example, according to FIG. 8. Thus, in the embodiments, it may be possible to estimate the Y displacement by adding the two outputs (24 and 25) and / or estimate the X displacement by subtracting one of the two outputs (24 and 25) from the other. In this regard, it should be noted that the output response curves (24 and 25) of the active resonant circuit of the sensor pair are mirror images of each other, generally as in the example of FIG. 13 in the embodiments. The accurate determination of the Y displacement and / or X displacement can be performed by calibration, as described below with reference to FIG. 22, for example.

[0100] When operating an active sensor pair as illustrated in FIGS. 11 and 12, interference (crosstalk) may occur between the first sensing coil (1A) of the first active resonant circuit and the second sensing coil (1B) of the second active resonant circuit. This may occur, for example, when the resonant frequency of the first active resonant circuit is close to or equal to the resonant frequency of the second active resonant circuit, which may be the case when a single passive resonant circuit (51) is used for the sensor. Since such interference can cause the output of the first active resonant circuit and the output of the second active resonant circuit to be non-independent, it may potentially degrade or hinder the accurate determination of the relative X and Y displacements of the active sensor pair and the passive circuit. The interference can be reduced by adjusting the resonant frequency of the first active resonant circuit differently from the resonant frequency of the second active resonant circuit, for example, offset and / or substantially differently. (In the embodiments, since this difference can be defined in relation to the widths of the resonant peaks, the resonant peak of the first active resonant circuit does not overlap with the resonant peak of the second active resonant circuit. In this regard, regarding 'overlap,' it is desirable that the resonant amplitude be reduced by about 6 dB - 12 dB (or more) at the point between each resonant peak). Additionally or alternatively, interference reduction can be achieved using two substantially identical passive resonant circuits, each of which is tuned to the resonant frequency of at least one of the active resonant circuits (preferably each) or a frequency close to it. (In the embodiments, 'identical' generally means that they are located close to each other and attached to a common substrate so that when one target moves, the other target moves with it. The windings of each identical target may be interleaved or overlapped, or alternatively, placed side by side.)Additionally or alternatively, this reduction can be achieved by using a driving circuit operating at two different driving frequencies (one frequency for each active resonant circuit). For some embodiments, the approach illustrated in FIG. 14 may be more preferable, but it should be noted that this approach can be applied in combination with any of the interference reduction techniques described above.

[0101] FIG. 14 illustrates a modified active resonant circuit, which can be used to reduce interference between the sensing induction coils of a plurality of active resonant circuits, for example, interference between the respective sensing coils of an active sensor pair as illustrated in FIG. 11 or 12. Preferably, mute switch(s) are used in at least one of the active circuits (preferably in both of the pair) to controllably mute, i.e., reduce or suppress, resonance and / or RF transmission from the sensing coil(s) of the active circuit. This may be advantageous when the sensing coils are placed very close to each other and / or are self-resonant (i.e., when one active circuit can induce resonance in an adjacent active circuit). In one example, an input mute switch (e.g., transistor (27)) is added to the input of the sensing coil (1). Additionally or alternatively, an output mute switch (e.g., transistor (28)) is added to the output of the sensing coil (1). A control line (e.g., a terminal or port) (29) is configured to receive a muting control signal. When the active resonant circuit is intended to be driven and resonate, the muting control signal may be set to an inactive state so that the muting transistor does not mute the transmission of the active circuit. Meanwhile, when the active resonant circuit is intended to be idle, the muting control signal may be set to an active state so that at least the output mute transistor (28) is connected to a fixed voltage such as ground (0V) or a DC voltage, which effectively dampens the vibration of the sensing coil (1). In embodiments where the active resonator receives a driving signal during the period during which the active circuit is intended to be idle, an input mute transistor (27) may be additionally provided so that the input line can be connected to a fixed voltage such as ground. However, if the driving signal is turned off during each idle period of the active resonant circuit, the input mute transistor may be omitted.In this way, multiple active resonant circuits, such as a pair of active sensors, can be operated in close proximity with little to no interference. This interference reduction can be improved by, preferably by controlled enabled output mute transistors, and by the driving signal(s) of the circuit and / or all input mute transistors, by activating only a few, preferably only one, of the multiple active resonant circuits at any given time. Additionally, with respect to optional features, for example, if the value of the input resistance (4) of the active circuit coupled with the output impedance of the driver is sufficiently low so that the driving signal can activate a muting operation with the output muting transistor (28) in an idle state, the input mute transistor may be omitted.

[0102] When multiple active sensor pairs (1A and 1B) operate very close to each other, for example as illustrated in FIG. 15, it may be advantageous to add a ground trace (61) and / or a ground plane, preferably on all conductive layers, between each active sensor pair. As illustrated in FIG. 15, a ground trace (61) may be provided between adjacent active sensor pairs and preferably integrated into a ground loop (60) that completely surrounds the active sensor pairs, so that the ground loop has a shared section between adjacent sensor pairs. This can reduce interference between each active sensor pair. If the ground trace forms a continuous loop (60 and 61) around the active sensor pairs, the inductance of each sensing inductor coil of each active resonant circuit of the active sensor pairs can be better shielded. The ground trace and / or loop may be advantageous in reducing inductance fluctuations of each sensing inductor coil, thereby ensuring that each active sensor pair responds similarly to the corresponding passive (preferably resonant) circuit. These measures can improve sensor performance due to controlled inductance value(s), reduced electromagnetic interference, and / or improved isolation of each sensor and / or interleaved coil pair within a multi-sensor system.

[0103] In some embodiments, multiple pairs of active sensors may be overlapped, for example as shown in FIG. 16, where the pairs are preferably formed on a PCB. (Fig. 15 shows ground loops around each active pair formed by features (60 + 61), whereas Fig. 16 forms a complete loop around each pair by 60 + 62 or 60 + 63, provided that they are not formed on all layers.) These overlapped pairs may be implemented in a system having individual actuators, i.e., keys, that are closely spaced apart from each other. The sensing induction coil (1A) of at least one pair of active sensors is preferably overlapped with the sensing induction coil (1B) of an adjacent pair of active sensors on different conductive layers of the PCB. In this case, it may not be possible to add a grounded trace (61) between each of the pairs of active sensors as shown in FIG. 15. However, the inventors discovered that adding grounded traces (62 and 63) to at least one layer not occupied by the sensing induction coils (preferably a layer of the PCB when used) can reduce interference between adjacent active sensor pairs and / or shield the inductance of each sensing induction coil of each active resonant circuit of the active sensor pairs. As illustrated in FIG. 16, some layer(s) may each have one or more ground loops containing traces (60 and 63) between adjacent spirals (on that layer) of coil (1A), while other interposed layer(s) may each have one or more ground loops containing traces (60 and 62) between adjacent spirals (on that layer) of coil (1B). Thus, ground traces and / or ground loops of different layers may overlap, as with interleaved pairs. In general, it is desirable that at least immediately adjacent, very closely adjacent, or overlapping / interleaved sensing coils are not activated simultaneously.Therefore, 1A and 1B may both be activated if they belong to different active pairs and are not adjacent or overlapping. In some embodiments, the active circuit containing the sensing coil (1A) is activated alternately with the active circuit containing the sensing coil (1B). Additionally or alternatively, only the active circuits having non-adjacent interleaved pairs may be activated simultaneously. In embodiments, the selective activation of the active circuits may be used to reduce interference and thereby improve the accuracy and / or reliability of position and / or movement detection, for example, between multiple actuators.

[0104] In addition to or alternative to one or more of the above interference reduction techniques, a controller may be used. For example, an active sensor pair or a plurality of active sensor pairs may include a controller that controls the selection and / or scanning of each active resonant circuit of the active sensor pair(s) so that adjacent active resonant circuits are driven at different times. This can reduce interference between sensors in the embodiments.

[0105] In some embodiments, the controller may be configured to perform time-division multiplexing of the sensors.

[0106] FIG. 17 illustrates an exemplary time-division multiplexing scheme for multiplexing a group of position and / or movement sensors including active resonant circuits as described above in relation to FIG. 14 and / or likewise. Each such circuit has output mute transistors and preferably further has input mute transistors and / or input resistors (4). Preferably, the circuit operates at a single resonant frequency. As shown in FIG. 17, the input line (e.g., terminal or port) (5) of each of the active resonant circuits is connected to the output of a first digital demultiplexer (38). The control line (e.g., terminal or port) (29) of each of the active resonant circuits is connected to the output of a second digital demultiplexer (e.g., inverting digital demultiplexer) (39). The output line (e.g., terminal or port) (6) of each of the active resonant circuits is connected to a sample-and-hold circuit (e.g., circuit according to FIG. 5). However, compared to FIG. 5, in FIG. 17, each active resonant circuit has an associated diode (26), but the sample-and-hold capacitive element (34) and / or sample-and-hold switch (35) may be shared between each active resonant circuit of the position and / or movement sensor group. The controller may preferably include processor(s) (40) that output one drive signal (42) to a first digital demultiplexer (38) and select signal(s) (41) to the first digital demultiplexer (38) and / or a second digital demultiplexer (e.g., an inverting digital demultiplexer) (39). Preferably, an analog-to-digital converter (43) within the processor may be connected to the output of the peak-hold circuit. The output (44) from the processor may transmit information regarding the position and / or movement of each of the position and / or movement sensors.The use of non-inverting and inverting digital demultiplexers (38 and 39, respectively, with reference to FIG. 17, or vice versa) is controlled by the same selection signal(s) so that only one active resonant circuit within the position and / or movement sensor group (or such a circuit pair in an embodiment using multiple active sensor pairs) is active for any time division period, and the other active resonant circuit is muted. (Note that for completeness only, any one or more of the digital circuit blocks, e.g., the demultiplexers (38 and / or 39), may be implemented using analog equivalent circuits in the embodiments.)

[0107] The following generally relates to a calibration process for an embodiment such as any one of the aforementioned and / or illustrated in the drawings. In this regard, the lateral spacing X corresponds to 'x' in the mathematical notation below, and the axial spacing Y corresponds to 'y'.

[0108] In an embodiment suitable for generating a normalized sensor output as illustrated in FIG. 13, the region of the output (24) from the first active resonant circuit (1A) of the active sensor pair measured according to the lateral interval X at a small axial interval (Y = 0) is a smooth lateral response function , for example, can be described as a cubic curve (65) as shown in Fig. 22.

[0109] Here, It could be.

[0110] The normalized axial response shown in Fig. 8 Expressed as, Y-dependent lateral sensitivity can be defined, and thereby the axial spacing As increases, the sensitivity of the active resonant circuit to the lateral spacing of the passive target decreases.

[0111] Here, It could be.

[0112] FIG. 22 illustrates exemplary lateral response outputs (65, 66, 67, and 68) of a first active resonant circuit, wherein the first active resonant circuit is a sensor (1A) having a response output such as that shown in the interleaved configuration of FIG. 12, for example, and that shown in FIG. 13, and as the axial (Y) intervals of the target spacing increase change axially (along the X-axis), the axial interval Y is smallest in the output response (65) and largest in the output response (68). As the axial interval Y increases, the sensor's Y-dependent lateral sensitivity for the lateral separation X of the passive target decreases, and the sensor's more general sensitivity to the presence of a target decreases likewise. In this case, the output response depending on both X and Y is a function in the example. It can be explained as.

[0113] Here It could be.

[0114] Here, D is the signal output value at the axial spacing, and this output and / or spacing can be regarded as the maximum output value and maximum axial spacing for the X range under consideration. These maximum values ​​correspond to the case where the interaction between the active resonant circuit and the passive target is minimized. Therefore, D is preferably the signal output value that would be output from the active resonant circuit in the absence of the passive circuit or at least in the absence of the target coil. In practice, the maximum value D may never be measured when the passive circuit or target coil of the embodiment is present. Thus, the value of D may be a value determined by measurement during assembly, before the passive circuit or target coil is added to the system being assembled. Alternatively, the value of D may be a predetermined reference value and may be estimated, for example, based on experience and / or measurements regarding the relevant actual implementation of the system.

[0115] In an active sensor pair, due to symmetry, the output of the second active resonant circuit can be substantially a mirror image of the output of the first active resonant circuit, so the output is It can be described as.

[0116] and An approximation of can be obtained by calculating the sum and difference of these sensor outputs, where Is The approximate value of the location, Is Provides an approximate value of the location.

[0117] Here, It could be.

[0118] Here, It could be.

[0119] While these approximations may be desirable in some applications, these It is not completely independent of the changes. Therefore, In the case of a significant change, A function that does not depend on Arbitrary (unknown) described as at the location A method for determining the location may be desirable.

[0120] The inventor It was discovered that one of the appropriate definitions of can be derived as shown in the following [Mathematical Equation 1]. for The ratio is calculated and expanded as shown below.

[0121]

[0122] Dependence on (i.e., ) can be removed by subtracting 2D from the denominator as shown in the following [Equation 2].

[0123]

[0124] thus, An appropriate function independent of It is equal to the following [Mathematical Formula 3].

[0125]

[0126] The advantages of using this correction method are in the examples. go Not only independent of or It does not depend on the shape of either. Therefore, any monotonic region of the curve shown in Fig. 8 is It can be used to represent. Likewise, any monotonic region of the curve illustrated in Fig. 10 is It can be used to represent.

[0127] From the measured value, X can be determined in various ways. For example, once Determine , and X is It can be determined from the algebraic or numerical solution of. Alternatively, It can be measured at two or more known X locations, and A calibration function (linear or other form) can be generated so that X can be determined from the measured value.

[0128] Similarly, once X is determined, Y can be determined in various ways, for example It can be determined by calculating Y from the algebraic or numerical solution of.

[0129] To a person skilled in the art, undoubtedly many other effective alternatives will come to mind. It should be understood that the present disclosure is not limited to the described embodiments and includes modifications obvious to a person skilled in the art that fall within the spirit and scope of the claims appended herein. Explanation of the symbols

[0130] 1A: First sensing induction coil 1B: Second sensing induction coil 15: First prepreg layer 16: Second prepreg layer 17, 18, 19, 20: Challengers 22: Sensing axis 23: Overlapping area

Claims

Claim 1 A sensing system for detecting position and / or movement comprises at least one active resonant circuit, each having a sensing coil for emitting an RF (radio frequency) signal—each sensing coil comprising at least one set of windings around an axis—and a passive circuit having a target coil for receiving RF energy from each sensing coil—the target coil comprising at least one set of windings around an axis, wherein for each active resonant circuit, At least one of the passive circuit and the active resonant circuit is configured to output a signal according to the degree of overlap between the target coil and the sensing coil of the active resonant circuit when the active resonant circuit is driven and the axes of the target coil and the sensing coil are maintained substantially parallel, thereby indicating the relative position and / or movement of the target coil and the sensing coil, wherein the relative position and / or movement substantially exist within a relative position range including at least one limit, and the at least one limit is A first relative position in which the first axis of the first coil is aligned with the outermost edge of the side of the winding set of the second coil; and / or A sensing system comprising a first axis including a second relative position aligned with the innermost edge of the side of the winding set of the second coil, wherein the first coil and the second coil include the target coil and the sensing coil. Claim 2 In claim 1, the axis of the second coil is a second axis extending preferably substantially to the center between the inner edge and the outer edge of the winding set of the second coil, and the range is a sensing system comprising an intermediate relative position in which the first axis is aligned within the second axis. Claim 3 A sensing system according to claim 1 or 2, wherein the first axis extends substantially through the center of the winding set of the first coil. Claim 4 A sensing system configured to provide an output signal that changes substantially monotonically according to a monotonic change in a relative position in a lateral direction substantially perpendicular to the axial direction while the first coil and the second coil face each other with a relative distance fixed in the axial direction. Claim 5 A sensing system configured to provide an output signal that changes substantially monotonically according to a monotonic change in the relative position in the axial direction while the first coil and the second coil have a relative spacing fixed in the lateral direction. Claim 6 In claims 4 and 5, the apparatus comprises at least one measurement circuit for generating a measurement signal indicating position and / or movement, wherein the at least one measurement circuit is, Based on the output signal that changes substantially monotonically according to the monotonic change of the relative position in the axial direction at a first point in time, an axial measurement signal is generated, and A sensing system configured to generate a lateral measurement signal based on the output signal, which changes substantially monotonically according to the monotonic change of the relative position in the lateral direction at a second point in time. Claim 7 A sensing system according to any one of the prior claims, wherein the target coil and / or each sensing coil is a planar coil comprising at least one planar spiral. Claim 8 A sensing system according to any one of the prior claims, comprising a sensor having at least one active resonant circuit and the passive circuit, wherein the at least one active resonant circuit comprises a pair of the active resonant circuits, each of the pair comprises a sensing coil comprising a plurality of sets of windings, each set comprising a spiral, and the spirals of the sensing coils of each of the pair of active resonant circuits are interleaved. Claim 9 In claim 8, the interleaved spirals of each of the above-mentioned sensing coils are located on opposite sides of an intermediate insulating layer, such as a printed circuit board core, and on the first side of the intermediate insulating layer, the region of the spiral of the first sensing coil is located between the intermediate insulating layer and the region of the spiral of the second sensing coil, so that the regions of the spirals overlap, and on the opposite side of the intermediate insulating layer, the region of the other spiral of the first sensing coil is located between the intermediate insulating layer and the region of the other spiral of the second sensing coil, so that the regions of the spirals overlap, a sensing system. Claim 10 In claim 8 or 9, the sensing system comprises a measuring circuit for indicating axial and lateral positions and / or movements, and each of the lateral positions and / or movements is, The target axis, which is the axis of the target coil; and The sensing axis, which is the axis of the sensing coil of the pair of active resonant circuits—the sensing axis extends between the inner and outer edges of the overlapping region of the sets of windings of the interleaved spirals, preferably substantially across the center—is relative to the measuring circuit, and the measuring circuit is configured to indicate a range of relative positions of the target axis and the sensing axis, and the range is, A first relative position in which the target axis is aligned with the first edge of the overlap region; and A sensing system in which the target axis is within a second relative position aligned with the opposite edge of the overlapping area, preferably the range includes an intermediate relative position in which the target axis is aligned with the sensing axis. Claim 11 In claim 10, the sensing system is configured such that the measurement circuit indicates the axial and lateral positions based on the output signals received substantially simultaneously from each of the pair of active resonant circuits. Claim 12 A sensing system configured to generate a lateral position and / or movement indicator in accordance with claim 10 or 11 by subtracting a measurement of the output signal from the other of the pair from a measurement of the output signal from one of the pair of active resonant circuits. Claim 13 A sensing system configured to generate an axial position and / or movement indicator by adding the measured value of the output signal from one of the pair of active resonant circuits and the measured value of the output signal from the other of the pair, in any one of claims 10 to 12. Claim 14 A sensing system according to claims 12 and 13, configured to generate a two-dimensional position and / or movement indicator based on a lateral indicator and an axial indicator, and configured to generate the lateral and axial indicators based on the same measurements of output signals from the pair of active resonant circuits. Claim 15 In any one of claims 8 to 14, the calibration process is configured to perform and indicate the relative position and / or movement of the target coil and the sensing coil, and the calibration process is the output response of each of the pair of active resonant circuits It includes determining, and the determined output responses are the output responses of the first circuit among the active resonant circuits. and output response of the other second active resonant circuit Includes, and the output response The decision is at least, Axial spacing During a constant period, different lateral intervals By measuring the output signal from the active resonant circuit, the lateral response Creating; Lateral spacing While constant, different axial intervals By measuring the output signal from the active resonant circuit, the lateral response Creating; Lateral sensitivity depending on Determining; and Output response according to Deciding— is a determination procedure including a reference signal output value at an axial interval, and the output response The above decision of, Performing the above determination procedure for the above other second active resonant circuit; or for The reverse response that is the twist by Based on determining, indicating the above relative position and / or movement, Axial spacing based on Approximation of; and / or Lateral spacing based on A sensing system that performs by determining an approximation of. Claim 16 In claim 15, the relative position and / or movement is a function It includes determining the above axial spacing based on, and the difference and the above sum is Human detection system. Claim 17 A sensing system according to any one of claims 8 to 16, wherein the pair of active resonant circuits are driven one at a time and / or a plurality of subsets of the pair of active resonant circuits are operated one at a time, preferably each subset being a pair. Claim 18 A sensing system according to any one of claims 8 to 17, comprising conductive layers, wherein each of the pair of sensing coils has the interleaved spiral within each of the conductive layers, and at least one of the conductive layers has a ground loop surrounding the interleaved spiral on the layer and the pair of the interleaved spirals within the other conductive layer. Claim 19 In claim 18, the interleaved spirals of the pair of active resonant circuits overlap with the interleaved spirals of another pair of active resonant circuits, preferably each of the pair includes at least one ground loop surrounding the spirals of each of the pair of sensing conductive coils, and the ground loop lies in a plane between any of the spirals of the pair but does not include any of the spirals. Claim 20 In any one of claims 8 to 19, the pair of active resonant circuits have offset resonant frequencies, and the passive circuit comprises a pair of passive resonant circuits preferably positioned substantially the same location for inductively receiving energy from a corresponding one of the pair of active resonant circuits, and each of the passive resonant circuits has a resonant frequency substantially the same as the resonant frequency of each of the pair of active resonant circuits, and the system is configured to provide driving signals to drive each of the pair of active resonant circuits, and the driving signals have different driving frequencies. Claim 21 A sensing system according to any one of the prior claims, wherein the active resonant circuit comprises an output mute switch coupled to an output line of the sensing coil; and preferably an input mute switch coupled to an input line of the sensing coil, wherein each mute switch is configured to apply a fixed voltage to the coupled line when the active resonant circuit is not driven and / or is idle. Claim 22 In claim 21, the at least one active resonant circuit comprises a plurality of active resonant circuits, each having the output mute switch and preferably the input mute switch, and the sensing system is configured to selectively drive one of the active resonant circuits at a time to emit an RF signal and to control at least the output mute switch of each of the active resonant circuits that is not driven to apply the fixed voltage. Claim 23 An actuator comprising a sensing system of any one of the prior claims, the actuator comprising: a first element having at least the sensing coil of at least one active resonant circuit; and a second element having at least the target coil of the passive circuit, wherein the first and second elements face each other in an axial direction, and at least one of the first and second elements is movable laterally in a direction substantially perpendicular to the axial direction with respect to the other of the first and second elements, and preferably at least one of the first and second elements is movable in the axial direction with respect to the other of the first and second elements. Claim 24 In claim 23, the first element comprises an electrically conductive material and an electrically insulating spacer, such as an air gap between the electrically conductive material and at least one sensing coil, and / or the second element comprises an electrically insulating spacer, such as an air gap between the electrically conductive material and at least one target coil. Claim 25 The above-mentioned actuator-type piano keyboard of claim 23 or 24. Claim 26 A keyboard comprising a plurality of actuators according to any one of claims 23 to 25, wherein, preferably, each actuator comprises a plurality of first elements having a sensing coil, and each of the plurality of first elements is movable at least laterally in common with respect to the second element. Claim 27 An instrument having an actuator according to any one of claims 23 to 25 or a keyboard according to claim 26. Claim 28 A method for detecting position and / or movement, comprising the step of driving an active resonant circuit to emit an RF signal from a sensing coil of the active resonant circuit—the sensing coil comprises at least one set of windings about an axis—; A method for detecting position and / or movement, comprising: receiving energy from an emitted RF signal by a target coil of a passive circuit—the target coil comprises at least one set of windings about an axis—; outputting at least one signal from an active resonant circuit during the RF emission—each of which the at least one signal depends on the resonance of the active resonant circuit—; determining the relative position and / or movement of the target coil and the sensing coil based on one or more of the signals output when the relative positions of the target coil and the sensing coils are substantially located within a range having at least one limit—the at least one limit includes a first relative position in which the center axis of the target coil is aligned with the outermost winding on one side of the sensing coil, and / or a second relative position in which the center axis of the target coil is aligned with the innermost winding on one side of the sensing coil.

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