Displacement detection device, displacement detection method, and manipulated variable output device

Abstract

To secure detection accuracy of a displacement amount while securing a range in which the displacement amount of a movable member can be detected.SOLUTION: A displacement amount detector 1 includes: a reaction body including a metal piece or a passive coil; a first substrate circuit 61 which includes a first coil 611 generating a magnetic field by supplying an AC signal and outputs a first detection signal with amplitude corresponding to a distance with the reaction body; a second substrate circuit 62 which includes a second coil 622 which generates a magnetic field by supplying the AC signal and outputs a second detection signal with amplitude corresponding to the distance with the reaction body; and a difference output circuit 90 for outputting a difference between amplitude of the first detection signal and amplitude of the second detection signal.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to, for example, a displacement detection device, a displacement detection method, and an operation amount output device.

Background Art

[0002] Conventionally, for example, a technique for detecting the displacement amount of a movable member such as a key in a keyboard instrument using two coils has been proposed. Specifically, a detected portion installed on the movable member and including one of the coils, the other of the coils that generates a magnetic field by supplying an alternating current signal, and a signal generation unit that generates a detection signal at a level corresponding to the distance between the detected portion and the other of the coils, and a magnetic body installed on at least one of the movable member and the signal generation unit have been proposed (see Patent Document 1).

[0003] According to this technique, a current is generated in one of the coils by electromagnetic induction due to the magnetic field of the other of the coils, and a magnetic field in a direction that cancels the magnetic field of the other of the coils is generated in one of the coils. Therefore, a detection signal at a level corresponding to the distance between the detected portion and the other of the coils is generated by the signal generation unit. According to the above technique, since the magnetic field generated in one of the coils or the other of the coils is enhanced by the magnetic body installed on at least one of the movable member and the signal generation unit, there is an advantage that it is easy to secure the range in which the level of the detection signal changes, that is, the detectable range of the displacement amount in the movable member.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, while the above technology can ensure a certain range of detectable displacement in the movable member, the change in the detection signal level decreases as the two coils move further apart. Therefore, there is a problem in that the accuracy of detecting the displacement of the movable member decreases when the two coils are separated. In consideration of the above circumstances, one aspect of this disclosure aims to ensure the accuracy of detecting the displacement amount while ensuring a certain range in which the displacement amount of the movable member can be detected. [Means for solving the problem]

[0006] A displacement detection device according to one aspect of the present disclosure is a displacement detection device for detecting the amount of displacement of a movable member, comprising: a reactant including a metal piece or a passive coil provided on the movable member; a first circuit board circuit including a first coil that generates a magnetic field by supplying an AC signal and outputs a first detection signal with an amplitude corresponding to the distance from the reactant; a second circuit board circuit including a second coil that generates a magnetic field by supplying the AC signal and outputs a second detection signal with an amplitude corresponding to the distance from the reactant; and a difference output circuit that outputs the difference between the amplitude of the first detection signal and the amplitude of the second detection signal. [Brief explanation of the drawing]

[0007] [Figure 1] This is a diagram illustrating the principle of displacement detection. [Figure 2] This is a diagram showing the circuit board in a displacement detection device. [Figure 3] This figure shows the main parts of the displacement detection device according to the first embodiment. [Figure 4] This figure shows the characteristics of the change in reactance with respect to displacement. [Figure 5] This is a plan view showing the main parts of the displacement detection device according to the second embodiment. [Figure 6] This is a plan view showing the circuit board of a displacement detection device. [Figure 7] This is a block diagram showing the configuration of a displacement detection device. [Figure 8]This figure shows the relationship between the difference output and the amount of displacement in a displacement detection device. [Figure 9] This is a block diagram showing the manipulated variable output device according to the third embodiment. [Figure 10] This diagram shows the area around the key, which is a movable component. [Figure 11] This figure shows the area around the key in the control input output device according to the fourth embodiment. [Figure 12] This figure shows the relationship between differential output and displacement. [Modes for carrying out the invention]

[0008] Hereinafter, a displacement detection device according to an embodiment of this disclosure will be described with reference to the drawings. In each figure, the dimensions and scale of each part have been appropriately altered from those of the actual parts. Furthermore, the embodiments described below are preferred examples and are subject to various technically preferable limitations. However, the scope of the present invention is not limited to these forms unless otherwise stated in the following description.

[0009] Figure 1 is a diagram illustrating the principle of displacement detection. Displacement detection utilizes the fact that the coupling coefficient of two coils is a function of distance, and detects this distance as the displacement. The substrate circuit 40 includes a coil 401 and a capacitive element 402. The coil 401 is a planar loop coil formed by, for example, spirally patterning copper foil provided on the surface of an insulating substrate. One end of the coil 401 is connected to one end of the capacitive element 402, and the other end of the coil 401 is connected to the other end of the capacitive element 402.

[0010] The circuit board 60 includes a coil 601, a resistor 602, and capacitive elements 603 and 604. In the circuit board 60, the input terminal In is connected to one end of the resistor 602, and the other end of the resistor 602 is connected to one end of the coil 601 and one end of the capacitive element 603. The other end of the coil 601 is connected to one end of the capacitive element 604 and the output terminal Out. The other end of the capacitive element 603 and the other end of the capacitive element 604 are grounded to potential Gnd. Coil 601, like coil 401, is a planar loop coil formed by spirally patterning copper foil provided on the surface of an insulating substrate.

[0011] Unlike coil 601, coil 401 does not receive a signal from an external source. In other words, coil 401 is passive, unlike the active coil 601. For this reason, coil 401 is also called a passive coil.

[0012] In this configuration, when the circuit board 40 is displaced relative to the circuit board 60 in the vertical direction (z-direction) of the circuit board surface while keeping the circuit board surface parallel, the inductance of the coil 601 in the circuit board 60 changes. Therefore, the amplitude of the AC signal output from the output terminal Out changes in relation to the amplitude of the AC signal input to the input terminal In. Specifically, if the amount of displacement is small, the amplitude of the output signal increases, and if the amount of displacement is large, the amplitude of the output signal decreases. Thus, the magnitude of the output signal amplitude represents the amount of displacement.

[0013] If circuit board 40 and circuit board 60 are in close contact, the coupling coefficient of coils 401 and 601 becomes "1". If the coupling coefficient is "1", circuit board 60 can be replaced with circuit board 61 as shown in Figure 2. This equivalent circuit functions as an anti-resonant circuit in which the ratio of the amplitude of the output signal to the amplitude of the input signal decreases sharply near the resonant frequency.

[0014] The substrate circuit 61 includes a coil 611, a capacitive element 612, and resistive elements 613 and 614. Specifically, in the substrate circuit 61, an input terminal In is connected to one end of the coil 611, one end of the capacitive element 612, and one end of the resistive element 613. The other end of the coil 611, the other end of the capacitive element 612, and the other end of the resistive element 614 are connected to one end of the resistive element 614 and an output terminal Out. The other end of the resistive element 614 is grounded to a potential Gnd.

[0015] The coil 401 in the substrate circuit 40 serves to change the inductance of the coil 611 according to the displacement amount. If it serves this role, the substrate circuit 40 can be substituted with, for example, an iron metal piece. When the substrate circuit 40 or the metal piece faces the substrate circuit 60, the inductance L of the coil 611 becomes a function of the distance in the z direction from the metal piece and the overlapping rate of the metal piece with respect to the coil 601. This point will be described using FIGS. 3 and 4. Note that either the substrate circuit 40 or the metal piece may face the substrate circuit 60. In the following description, it will be described assuming that the metal piece faces it.

[0016] FIG. 3 is a diagram showing a main part of the displacement amount detection device according to the first embodiment. Specifically, it is a perspective view showing the positional relationship between the substrate circuit 61 and the plate-shaped metal piece 50 that is the detection target of the displacement amount. The coil 611 is a planar loop coil provided in the xy plane. The outer shape of the coil 601 is, for example, a square frame, and in the figure, the coil 611 is shown as a thick square plate for convenience. Note that the y direction is the direction along the side L1 of the coil 611, the x direction is the direction along the side L2 adjacent to the side L1, and the z direction is the vertical direction of the xy plane. The metal piece 50 is provided in close contact or separated along the z direction with respect to the coil 611.

[0017] The outer shape of the metal piece 50 is assumed to be greater than or equal to the outer shape of the coil 611 when viewed from above. Figure 3 shows an example where the width of the metal piece 50 in the x-direction is the same as the width of the coil 611 in the x-direction, and the width of the metal piece 50 in the y-direction is wider than the width of the coil 611 in the x-direction. Note that a plan view refers to viewing from the opposite side in the z-direction.

[0018] Here, when viewed from above, the displacement in the x-direction is defined as zero when side L11 of the metal piece 50 coincides with side L1 of the coil 611, as shown in the figure. Furthermore, the overlap rate is defined as the proportion to which the metal piece 50 covers the coil 611. More specifically, the overlap rate is the proportion of the area of ​​the coil 501 covered by the metal piece 50 when viewed from above. For example, if the displacement in the x-direction is zero, the coil 611 is completely covered by the metal piece 50 when viewed from above, so the overlap rate is "1". If the metal piece 50 is displaced in the x-direction and its side L11 coincides with the center line Cen of the coil 611, the overlap rate is "0.5". The center line Cen is a virtual line that, when viewed from above, passes through the midpoint of side L2 of the coil 611 and is aligned with the y-direction. Also, if side L11 of the metal piece 50 is displaced in the x-direction more than side L3 opposite side L1 of the coil 611 when viewed from above, the overlap rate is "0".

[0019] The plate-shaped metal piece 50 is made of iron, for example, and is displaced in the x-direction while maintaining a predetermined distance in the z-direction from the surface of the coil 611.

[0020] Figure 4 shows the change in inductance L of coil 611 when the metal piece 50 is displaced in the x direction so that the overlap rate changes from "0" to "1" while the distance in the z direction is fixed for multiple types. In the figure, the inductance L is normalized with a minimum value of "0" and a maximum value of "1". As shown in this figure, the shorter the distance in the z direction, the greater the change in inductance L in response to the change in overlap ratio. A large change in inductance L means that the amplitude of the AC signal output from the output terminal Out changes significantly.

[0021] As can be seen from Figure 4, for example, when the overlap rate is large (for example, when it is "1"), even if the distance in the z direction changes while the distance is long, the change in inductance L is small, so the rate of change in the amplitude of the output AC signal becomes small. For this reason, when the distance in the z direction is long, the rate of change in the amplitude of the output AC signal becomes small, and high detection accuracy cannot be expected. On the other hand, if the metal piece 50 is displaced in the x-direction such that the overlap ratio changes when the distance in the z-direction is short, the change in inductance L becomes larger, and an improvement in detection accuracy can be expected. However, the range in which the amount of displacement in the x-direction can be detected by changing the overlap ratio is limited to the range from "0" to "1".

[0022] Therefore, a second embodiment is described, which improves upon the first embodiment by detecting the displacement of the metal piece 50 using two coils. The two coils are referred to as the first coil 611 and the second coil 622 for distinction, but the first coil 611 is the same as the coil 611 in Figure 2 or Figure 3, and therefore uses the same reference numeral.

[0023] Figure 5 shows the arrangement of the metal piece 50, which is the object of displacement detection, and the first coil 611 and the second coil 622 in the displacement detection device 1 according to the second embodiment. Figure 6 shows the first circuit board 61 including the first coil 611 and the second circuit board 62 including the second coil 622. Figure 7 is a block diagram showing the configuration of the displacement detection device 1.

[0024] Each of the first coil 611 and the second coil 622 is a planar loop coil provided in the xy plane, similar to coil 611 in Figure 2, and is formed, for example, by spirally patterning copper foil provided on the surface of an insulating base material 16. The outer shape of the first coil 611 and the second coil 622 is rectangular in plan view, for example, 10 mm square. The first coil 611 and the second coil 622 are arranged side by side along the x direction, for example, at a pitch of 16 mm. Therefore, there is a gap of about 6 mm between the first coil 611 and the second coil 622.

[0025] The metal piece 50 is displaced in the x-direction while being separated by 1 mm in the z-direction from the planes of the first coil 611 and the second coil 622. Note that the x-direction is an example of the first direction. If the metal piece 50 and the first substrate circuit 61 or the second substrate circuit 62 are in close contact with each other, the coupling coefficient is "1", but physically it is difficult to displace the metal piece 50 while they are in close contact. However, if they are separated by a distance of about 1 mm, it can be considered electrically equivalent to being in close contact, and the metal piece 50 can be displaced relative to the first substrate circuit 61 and the second substrate circuit 62.

[0026] In the figure, point (a) where the left end of the metal piece 50 coincides with the left end of the first coil 611 in a plan view is the point where the displacement of x is zero (origin). When the metal piece 50 is located at point (a), the overlap rate of the metal piece 50 with respect to the first coil 611 is "1", and the overlap rate of the metal piece 50 with respect to the second coil 622 is "0".

[0027] Furthermore, in the figure, at point (b) where the right end of the metal piece 50 coincides with the right end of the second coil 622 in a plan view, the displacement of x is 16 mm. When the metal piece 50 is located at point (b), the overlap rate of the metal piece 50 with respect to the first coil 611 is "0", and the overlap rate of the metal piece 50 with respect to the second coil 622 is "1".

[0028] As shown in Figure 6, the first substrate circuit 61 has a circuit configuration similar to that of substrate circuit 60. To distinguish between the two, the input terminal on the first circuit board 61 is designated as in1 and the output terminal as Out1, while the input terminal on the second circuit board 62 is designated as in2 and the output terminal as Out2. The spiral center of the first coil 611 is connected to the output terminal Out1 via contact hole Ct1, the wiring shown by the dashed line, and contact hole Ct2 in that order. Furthermore, the first substrate circuit 61 and the second substrate circuit 62 may be provided on the same substrate 16, or they may be provided on different substrates 16.

[0029] In this embodiment, the direction of the spiral in the first coil 611 in the first circuit board 61 and the direction of the spiral in the second coil 622 in the second circuit board 62 are the same. Therefore, when the same AC signal is supplied to input terminals In1 and In2, magnetic fields are generated in the z-direction or in the opposite direction to the z-direction.

[0030] As shown in Figure 7, the displacement detection device 1 includes an oscillation circuit 30, a first substrate circuit 61, a second substrate circuit 62, rectifier circuits 81 and 82, and a difference output circuit 90. Note that the metal piece 50 is omitted. The oscillation circuit 30 generates an AC signal for measurement and supplies this AC signal to the input terminal In1 of the first circuit board 61 and the input terminal In2 of the second circuit board 62, respectively. The frequency of the AC signal for measurement is set according to the resonant frequencies of the first circuit board 61 and the second circuit board 62.

[0031] The rectifier circuit 81 rectifies and smooths the AC signal output from output terminal Out1 and outputs it as signal Ev1. The AC signal output from output terminal Out1 is an example of the first detection signal. The rectifier circuit 82 rectifies and smooths the AC signal output from output terminal Out2 and outputs it as signal Ev2. The AC signal output from output terminal Out2 is an example of the second detection signal. The differential output circuit 90 subtracts the voltage of signal Ev2 from the voltage of signal Ev1 and outputs it as signal D. The voltage of signal D reflects the displacement in the x-direction of the metal piece 50.

[0032] In this configuration, when the displacement of the metal piece 50 in the x-direction is 0 mm, the overlap ratio of the first coil 611 due to the metal piece 50 is "1", so the amplitude of the AC signal output from the output terminal Out1 of the first circuit board 61 is maximized. In this case, the overlap ratio of the second coil 622 due to the metal piece 50 is "0", so the amplitude of the AC signal output from the output terminal Out2 of the second circuit board 62 is minimized. When the metal piece 50 is displaced in the x-direction, the overlap ratio of the first coil 611 due to the metal piece 50 decreases from "1" inversely proportional to the amount of displacement, so the amplitude of the AC signal output from the output terminal Out1 of the first circuit board 61 decreases according to the amount of displacement.

[0033] When the metal piece 50 is displaced in the x-direction and the amount of displacement exceeds 6 mm, the amplitude of the AC signal output from the output terminal Out1 of the first circuit board 61 continues to decrease in proportion to the amount of displacement. On the other hand, as the overlap rate of the second coil 622 due to the metal piece 50 starts to increase from "0", the amplitude of the AC signal output from the output terminal Out2 of the second circuit board 62 gradually increases in proportion to the amount of displacement. When the metal piece 50 is displaced in the x-direction and the displacement reaches 10 mm, the overlap rate of the first coil 611 due to the metal piece 50 becomes "0". As a result, the amplitude of the AC signal output from the output terminal Out1 of the first circuit board 61 becomes its minimum value and remains almost unchanged from that minimum value even as the displacement increases. On the other hand, the overlap rate of the second coil 622 due to the metal piece 50 increases in proportion to the displacement, so the amplitude of the AC signal output from the output terminal Out2 of the second circuit board 62 continues to increase in proportion to the displacement. This trend continues until the displacement reaches 16 mm.

[0034] Therefore, the voltage of signal D, obtained by subtracting the voltage of signal Ev2 (which is obtained by subtracting the voltage of signal Ev2, which is obtained by subtracting the voltage of signal Ev2, which is obtained by subtracting the voltage of signal Ev2 (which is obtained by subtracting the voltage of signal Ev2, which is obtained by subtracting the voltage of signal Ev2, which is obtained by subtracting the voltage of signal Ev1, which is obtained by subtracting the voltage of signal Ev2, which is obtained by subtracting the voltage of signal Ev2, which is obtained by subtracting the voltage of signal Ev2, which is obtained by subtracting the voltage of signal Ev2, which is obtained by subtracting the voltage of signal Ev2, which is obtained by subtracting the voltage of signal Ev2, which is obtained by subtracting the voltage of signal Ev2, which is obtained by subtracting the voltage of signal Ev2, which is obtained by subtracting the voltage of signal Ev1 (which is obtained by subtracting the voltage of signal Ev2, which1, which is obtained by subtracting the voltage of signal Ev1, which is obtained by subtracting the voltage of signal Ev2, which is obtained by subtracting the voltage of signal Ev2, which is obtained by subtracting the voltage of signal Ev2, which is obtained by subtracting the voltage of signal Ev2, which is obtained by subtracting the voltage of signal Ev2, which is obtained by subtracting the voltage of signal Ev2, which Furthermore, in Figure 8, the voltage on the vertical axis is normalized, with the highest value of signal Ev1 set to "1" and the lowest value of -Ev2 (the inverted signal Ev2) set to "-1". Note that signal D becomes zero when the displacement of the metal piece 50 is at the midpoint between 0 mm and 16 mm (= 8 mm).

[0035] If only the first circuit board 61 exists and the second circuit board 62 does not, the displacement amount will be determined solely by the voltage of signal Ev1, so the range in which the displacement amount of the metal piece 50 can be detected is limited to 0 to 10 mm. Similarly, if only the second circuit board 62 exists and the first circuit board 61 does not exist, the displacement amount will be determined solely by the voltage of signal Ev2, so the range in which the displacement amount of the metal piece 50 can be detected is limited to 6 to 16 mm. In contrast, in the configuration shown in the second embodiment, where the displacement is determined by the voltage of signal D, which is the difference between the voltage of signal Ev1 and the voltage of signal Ev2, the range in which the displacement of the metal piece 50 can be detected is expanded to the range of 0 to 16 mm, as shown in Figure 8. Furthermore, the linearity of signal D can be ensured, except for the minimum value around 0 mm and the maximum value around 16 mm. Therefore, according to the second embodiment, compared to the first embodiment, it is possible to expand the range in which the displacement amount of the metal piece 50 can be detected while ensuring the linearity of the signal with respect to the displacement amount.

[0036] In the configuration shown in Figure 7, the reason why the AC signal output from the output terminal Out1 of the first circuit board 61 is rectified by the rectifier circuit 81 and the AC signal output from the output terminal Out2 of the second circuit board 62 is rectified by the rectifier circuit 82 before calculating the amplitude difference is as follows: Although the same AC signal from the oscillator circuit 30 is supplied to the input terminal In1 of the first circuit board 61 and the input terminal In2 of the second circuit board 62, the inductance of the first coil 611 and the inductance of the second coil 622 change depending on the amount of displacement in the x direction of the metal piece 50. Therefore, the phase of the AC signal output from the output terminal Out1 of the first circuit board 61 and the phase of the signal output from the output terminal Out2 of the second circuit board 62 are not necessarily aligned.

[0037] Figure 9 is a block diagram showing the configuration of the operator amount output device 2 according to the third embodiment, and Figure 10 is a diagram showing the configuration around a key 12, which is a movable member and an example of an operator. The operator amount output device 2 according to the third embodiment applies the displacement amount detection device 1 according to the second embodiment to the keyboard device 10 to detect the displacement amounts of each of the multiple keys 12 in the keyboard device 10, convert them into operator amounts, and output them.

[0038] In the keyboard device 10, one key 12 is pivotably supported on the upper surface 141 of the support member 14, with the pivot point 13 as the pivot. Specifically, the end portion 121 of the key 12 is displaced vertically in the figure by the user's operation of the key 12. The support member 14 is a fixed structure that supports each element of the keyboard.

[0039] The key 12 is biased counterclockwise around the pivot point 13 in the figure by an elastic force such as a spring (not shown). When the user is not operating the key 12, the key 12 remains stationary at the rest position Rst (solid line in the figure) by the stopper Sr. When the key is pressed, it is operated in direction A and displaced to the end position End (dashed line in the figure) by the stopper Se.

[0040] In the key 12, a metal piece 50 is provided on the end face 122 on the far side as seen from the user. As the key 12 is pressed, the metal piece 50 is displaced upward in the figure. Therefore, from the perspective of the displacement detection device 1, upward is the x-direction in the figure. Note that the direction in which the multiple keys 12 are arranged, i.e., the direction towards the viewer on the page, is the y-direction, and the direction in which the long key 12 faces the user, i.e., the rightward direction in the diagram, is the z-direction.

[0041] A base material 16 is erected on the upper surface 141 of the support member 14. The upper surface 141 is a plane along the y and z directions. As described above, the first coil 611 and the second coil 622 are arranged side by side on the base material 16 along the x direction. The first coil 611 and the second coil 622 are provided in the following positional relationship with respect to the metal piece 50, for example: when the key 12 is in the rest position Rst, the first coil 611 faces the metal piece 50, and when the key 12 is in the end position End, the second coil 622 faces the metal piece 50. Although Figure 10 shows a white key as an example of a key 12, the first circuit board circuit 61, the second circuit board circuit 62, and the metal piece 50 are similarly provided for the black key as well.

[0042] The manipulated variable output device 2 according to the third embodiment, as shown in Figure 10, includes an oscillator circuit 30, a demultiplexer 71, a multiplexer 72, n sets of first board circuits 61 and second board circuits 62, a rectifier circuit 80, an AD conversion circuit 75, and an information processing circuit 100. Hereinafter, n is an integer of 2 or more. The information processing circuit 100 outputs a selection signal Sel_Ch for selecting the output terminal of the demultiplexer 71 and the input terminal of the multiplexer 72. The information processing circuit 100 also receives the output signal of the AD conversion circuit 75 and calculates the key press amount (operation amount) Dx for each of the n keys 12.

[0043] The demultiplexer 71 has an input terminal in and output terminals Ch_1 to Ch_(2n), and outputs the AC signal from the oscillator circuit 30 supplied to the input terminal In from the output terminal selected by the selection signal Sel_Ch. The output terminal Ch_1 of the demultiplexer 71 is connected to the input terminal In1 of the first circuit board 61, which corresponds to the first key 12, and the output terminal Ch_2 is connected to the input terminal In2 of the second circuit board 62, which also corresponds to the first key 12. Generally, when an integer i between 1 and (n / 2) is used, the output terminal Ch_i of the demultiplexer 71 is connected to the input terminal In1 of the first circuit board 61 corresponding to the i-th key 12, and the output terminal Ch_(i+1) is connected to the input terminal In2 of the second circuit board 62 corresponding to the same i-th key 12.

[0044] The multiplexer 72 has input terminals Ch_1 to Ch_(2n) and an output terminal out, and outputs the signal supplied to the input terminal selected by the selection signal Sel_Ch from the output terminal out. The output terminal Out1 of the first circuit board 61, which corresponds to the first key 12, is connected to the input terminal Ch_1 of the multiplexer 72, and the output terminal Out2 of the second circuit board 62, which also corresponds to the first key 12, is connected to the input terminal Ch_2 of the multiplexer 72. When the above integer i is used, the output terminal Out1 of the first circuit board 61 corresponding to the i-th key 12 is connected to the input terminal Ch_i of the multiplexer 72, and similarly, the output terminal Out2 of the second circuit board 62 corresponding to the i-th key 12 is connected to the input terminal Ch_(i+1) of the multiplexer 72.

[0045] The rectifier circuit 80 rectifies and smooths the AC signal output from the output terminal out of the multiplexer 72 and outputs it as a signal Ev. The AD conversion circuit 75 converts the analog signal Ev into a digital signal and supplies it to the information processing circuit 100.

[0046] The information processing circuit 100 is composed of one or more control devices, such as a CPU (Central Processing Unit), and the time-division selection unit 101, the calculation unit 102, and the conversion unit 103 are constructed by executing a program stored in a memory device (not shown). The information processing circuit 100 may be composed of circuits other than the CPU, such as a DSP (Digital Signal Processor) or an ASIC (Application Specific Integrated Circuit).

[0047] The time-division selection unit 101 specifies the selection of the output terminals of the demultiplexer 71 and the input terminals of the multiplexer 72 in the following order, for example, based on the selection signal Sel_Ch. Specifically, the time-division selection unit 101 selects the output terminals of the demultiplexer 71 and the input terminals of the multiplexer 72 in the order Ch_1→Ch_2→Ch_3→Ch_4→…→Ch_(2n-1)→Ch_(2n)→(Ch_1), and repeats this selection operation. Therefore, the demultiplexer 71 distributes the AC signal from the oscillator circuit 30 to output terminals Ch_1 to Ch_(2n) in a time-division manner, and the multiplexer 72 selects the signal to input terminals Ch_1 to Ch_(2n) in a time-division manner.

[0048] The calculation unit 102 subtracts the digital value of signal Ev when the following even-numbered input and output terminals are selected from the digital value of signal Ev when the odd-numbered input and output terminals are selected. Specifically, the arithmetic unit 102 holds the value of the digital signal Ev when the time-division selection unit 101 selects an odd-numbered input terminal and output terminal. Next, when the time-division selection unit 101 selects the next even-numbered input terminal and output terminal following the previous odd-numbered one, the arithmetic unit 102 subtracts the digital signal Ev, which is the output of the AD conversion circuit 75, from the held value of the digital signal Ev.

[0049] In other words, the calculation unit 102 digitally calculates and outputs the difference in amplitude of the AC signals output from the paired first circuit board circuit 61 and second circuit board circuit 62. Therefore, in the configuration shown in Figure 9, the calculation unit 102 functions as a difference output circuit. Strictly speaking, the difference calculated by the calculation unit 102 is not the difference in amplitude of the AC signals output simultaneously from the first circuit board 61 and the second circuit board 62, but rather a difference with a time lag. However, by shortening the selection period of the output terminal of the demultiplexer 71 and the input terminal of the multiplexer 72, or by shortening the selection repetition period, the above time lag can be ignored.

[0050] When the time-division selection unit 101 selects an even-numbered input terminal and output terminal, the difference calculated by the calculation unit 102 is the difference in amplitude of the AC signals output from the odd-numbered first circuit board circuit 61 and the even-numbered second circuit board circuit 62 that precede the even-numbered terminal. Generally, using the integer i, when the even-numbered input terminal and output terminal selected by the time-division selection unit 101 is 2i, the difference calculated will represent the amount of displacement in the x-direction of the metal piece 50 provided on the i-th key 12.

[0051] The conversion unit 103 converts the displacement amount in the metal piece 50 into the key push amount Dx of the key 12 and outputs it in association with the identifier of the key 12. The identifier for key 12 is information used to distinguish between multiple keys 12, and in the example above, it is i, or more specifically, information indicating the pitch of key 12. Furthermore, the conversion in the conversion unit 103 can use, for example, a table that associates displacement and key press amount, or a linear calculation formula.

[0052] As shown in Figure 9, the configuration allows for the output of the key press amounts Dx of multiple n keys 12, associated with the identifiers of the keys 12. The information processing circuit 100 may supply the key press amounts Dx of the multiple n keys 12 to a device (not shown) to perform musical sound control, or the information processing circuit 100 itself may generate a musical sound signal based on the key press amount Dx, or it may be configured to convert the musical sound signal into physical sound and emit it.

[0053] Figure 11 shows the configuration around the key 12, which is a movable member, in the manipulated amount output device 2 according to the fourth embodiment. In the fourth embodiment, the first coil 611 is mounted on the upper side and the second coil 622 on the lower side between the bottom surface 123 of the key 12 and the upper surface 141 of the support member 14. More specifically, the surfaces of the first coil 611 and the second coil 622 are mounted parallel to the upper surface 141 by members not shown. The metal piece 50 is provided on the bottom surface 123 of the key 12, which is a movable member, and is bent at approximately 90 degrees, with the flat portion of its extension positioned between the first coil 611 and the second coil 622. Furthermore, the flat portion of the metal piece 50 is positioned so as to be approximately parallel to the upper surface 141.

[0054] In the configuration shown in Figure 11, the substrate surface of the first substrate circuit 61 and the substrate surface of the second substrate circuit 62 are parallel to the upper surface 141 of the support member 14 and are arranged side by side along the vertical direction of the upper surface 141. Furthermore, the metal piece 50 is displaced along this vertical direction. For this reason, this vertical direction is an example of the second direction.

[0055] The spiral direction of the first coil 611 and the spiral direction of the second coil 622 are set so that the direction of the magnetic field generated by the first coil 611 and the direction of the magnetic field generated by the second coil 622 are aligned. Specifically, when viewing the upper surface 141 of the support member 14 from above, the spiral direction of the first coil 611 and the spiral direction of the second coil 622 are set in the same direction.

[0056] In this configuration, when the key 12 is in the rest position Rst, the metal piece 50 is closest to the first coil 611, so the amplitude of the AC signal output from the output terminal Out1 of the first circuit board 61 is maximized. Also, when the key 12 is in the rest position Rst, the metal piece 50 is furthest from the second coil 622, so the amplitude of the AC signal output from the output terminal Out2 of the second circuit board 62 is minimized. As the key is pressed, the metal piece 50 moves away from the first coil 611, so the amplitude of the AC signal output from the output terminal Out1 of the first circuit board 61 gradually decreases. On the other hand, as the key is pressed, the metal piece 50 moves closer to the second coil 622, so the amplitude of the AC signal output from the output terminal Out2 of the second circuit board 62 gradually increases. When key 12 is in the end position, the metal piece 50 is furthest away from the first coil 611, so the amplitude of the AC signal output from output terminal Out1 of the first circuit board 61 is minimized. Also, when key 12 is in the end position, the metal piece 50 is closest to the second coil 622, so the amplitude of the AC signal output from output terminal Out2 of the second circuit board 62 is maximized.

[0057] Thus, in the fourth embodiment, the voltage of signal D obtained by subtracting the voltage of the rectified and smoothed AC signal output from the output terminal Ou2 of the even-numbered second circuit board 62, which follows the odd-numbered first circuit board 61, from the voltage of the signal obtained by rectifying and smoothing the AC signal output from the output terminal Out1 of the odd-numbered first circuit board 61, is as shown in Figure 12. The characteristics shown in Figure 12, compared to the characteristics shown in Figure 8, result in a narrower range over which the displacement of the metal piece 50 can be detected. However, with only the first circuit board 61, for example, in the region where the key press amount is large (the region where the displacement amount in the x-direction is large), the rate of change of the voltage of signal Ev1 in response to the change in displacement becomes small. Also, with only the second circuit board 62, in the region where the key press amount is small (the region where the variable amount in the x-direction is small), the rate of change of the voltage of signal Ev2 in response to the change in displacement becomes small. In contrast, in the fourth embodiment, the rate of change of the signal D in response to changes in displacement becomes large in both the large and small key press ranges, so high detection accuracy can be expected in both ranges.

[0058] In the fourth embodiment as well, with the configuration shown in Figure 9, the pressing amounts Dx of multiple n keys 12 can be associated with the identifiers of the keys 12 and output as operation information.

[0059] As described above, either the substrate circuit 40 or the metal piece 50 may face the substrate circuit 60, the first substrate circuit 61, or the second substrate circuit 62. In other words, the substrate circuit 60, the first substrate circuit 61, or the second substrate circuit 62 may face a reactant containing a passive coil 401 or a metal piece.

[0060] Furthermore, in the embodiments described above, the circuit characteristics of the first substrate circuit 61 and the second substrate circuit 62 do not necessarily need to be the same. For example, when the resistance value of the resistor element 613 in the second circuit board 62 increases, the Q value increases, and for the voltage of signal Ev2, as shown in (e) in Figure 12, the rate of change of voltage with respect to the displacement increases in the region of large displacement. Therefore, for signal D, as shown in (f), the voltage changes significantly for small displacements, improving the accuracy of displacement detection in this region. Although not specifically shown in the diagram, conversely, if the resistance value of the resistor element 613 in the second circuit board 62 decreases, the Q value decreases, and the rate of voltage change with respect to displacement decreases in the region of large displacement. Furthermore, although the resistive element 613 in the second circuit board 62 has been described here, the voltage change rate in the region of small displacement may be changed by modifying the elements of the first circuit board 61.

[0061] In the embodiments, for example, the first substrate circuit 61 may be a multilayer substrate, and the first coil 611 may be constructed by stacking multiple layers. Similarly, the second substrate circuit 62 may be a multilayer substrate, and the second coil 622 may be constructed by stacking multiple layers. By constructing the coil with multiple layers stacked together in this way, a magnetic field can be generated over a greater distance compared to a single layer, thus expanding the detection range.

[0062] Furthermore, although a key 12 was used as an example of an operating element in this explanation, the method is not limited to a key 12. For example, it may be applied to a slider to detect the displacement of the slider.

[0063] From the above description, preferred embodiments of the present invention can be understood, for example, as follows. For the sake of ease of understanding each embodiment, the reference numerals in the drawings are conveniently included in parentheses below, but this does not mean that the present invention is limited to the illustrated embodiments.

[0064] A displacement detection device according to one aspect of the present disclosure (Aspect 1) is a displacement detection device for detecting the displacement of a movable member, comprising: a reactant including a metal piece or a passive coil provided on the movable member; a first circuit board circuit including a first coil that generates a magnetic field by supplying an AC signal and outputs a first detection signal with an amplitude corresponding to the distance from the reactant; a second circuit board circuit including a second coil that generates a magnetic field by supplying the AC signal and outputs a second detection signal with an amplitude corresponding to the distance from the reactant; and a difference output circuit that outputs the difference between the amplitude of the first detection signal and the amplitude of the second detection signal.

[0065] In Embodiment 1, when a reactant obstructs the magnetic field generated by the first or second coil, both the amplitude of the first detection signal and the amplitude of the second detection signal change inversely depending on the position of the reactant. Specifically, if the reactant provided on the movable member approaches the first coil and moves away from the second coil, the amplitude of the first detection signal increases and the amplitude of the second detection signal decreases. Conversely, if the reactant moves away from the first coil and approaches the second coil, the amplitude of the first detection signal decreases and the amplitude of the second detection signal increases. Compared to a configuration that calculates the displacement amount using only the detection signal of a single substrate circuit (coil), this configuration allows for improved linearity between the amplitude difference and the displacement amount while maintaining a detection range.

[0066] The difference output circuit may output the difference between the first rectified signal obtained by rectifying the first detection signal and the second rectified signal obtained by rectifying the second detection signal, or it may output the difference between the digital voltage value of the first rectified signal obtained by rectifying the first detection signal and the digital voltage value of the second rectified signal obtained by rectifying the second detection signal.

[0067] In Embodiment 2, which is a specific example of Embodiment 1, the first coil is formed in a spiral shape on the substrate surface of the first substrate circuit, and the second coil is formed in a spiral shape on the substrate surface of the second substrate circuit. According to embodiment 2, since the first coil and the second coil are provided on the substrate surface, less space is required for installing the coils.

[0068] In embodiment 3, which is a specific example of embodiment 2, the first substrate circuit and the second substrate circuit are spaced apart in a first direction along the substrate surface, and in a plan view, part or all of the reactant is displaced along the first direction to the extent that it overlaps with the first coil or the second coil. According to embodiment 3, the amount of displacement of the reactant moving in the direction in which the first coil and the second coil are installed side by side can be detected.

[0069] In embodiment 4, which is another specific example of embodiment 2, the first substrate circuit and the second substrate circuit are spaced apart along a second direction vertical to the substrate surface, and the reactant is displaced along the second direction within the range between the first substrate circuit and the second substrate circuit. According to embodiment 4, the amount of displacement of the reactant moving between the first coil and the second coil can be detected.

[0070] In Embodiment 5, which is another specific example of Embodiment 1, there are multiple sets of the movable member, the first circuit board, and the second circuit board, and the supply of the AC signal and the output of the difference are performed by selecting one set of the multiple sets of the first circuit board and the second circuit board in a time-division manner. Since the differential output circuit is shared by multiple sets of the first and second board circuits, the configuration can be simplified compared to a configuration in which the differential output circuit is provided for each set of the first and second board circuits.

[0071] Embodiment 6, which is a specific example of Embodiment 5, includes a demultiplexer that distributes the AC signal to the plurality of sets of first board circuits or second board circuits in a time-division manner, and a multiplexer that time-divisionally selects a first detection signal from the first board circuit or a second detection signal from the second board circuit supplied with the AC signal by the demultiplexer and outputs it to the difference output circuit. According to embodiment 6, time-division supply of AC signals is realized by a demultiplexer, and time-division selection of a first detection signal and a second detection signal for outputting the difference is realized by a multiplexer.

[0072] In Embodiment 7, which is a specific example of Embodiment 1 or Embodiment 2, the Q value of the first substrate circuit and the Q value of the second substrate circuit are different. When the Q values ​​are different, the slope of the difference in amplitude with respect to the displacement amount will be different when the movable member is positioned closer to the first substrate circuit and when the movable member is positioned closer to the second substrate circuit. Therefore, according to Embodiment 7, the position detection accuracy when the reactant approaches either the first substrate circuit or the second substrate circuit can be improved.

[0073] Furthermore, another displacement detection device according to another embodiment 8 of the present disclosure is a displacement detection device for detecting the amount of displacement of a movable member, comprising: a reactant including a metal piece or a passive coil provided on the movable member; a substrate circuit including a coil that generates a magnetic field by supplying an AC signal and outputs a detection signal with an amplitude corresponding to the distance from the reactant; and the coil being formed in a spiral shape on the substrate surface of the substrate circuit, and the substrate circuit being an anti-resonance circuit including the coil.

[0074] A displacement detection method according to one aspect 9 of the present disclosure is a displacement detection method for detecting the displacement of a movable member provided with a reactant including a metal piece or a passive coil, comprising: supplying an AC signal to a first coil to generate a first detection signal with an amplitude corresponding to the distance to the reactant; supplying an AC signal to a second coil to generate a second detection signal with an amplitude corresponding to the distance to the reactant; and outputting the difference between the amplitude of the first detection signal and the amplitude of the second detection signal.

[0075] An operation amount output device for an operator according to one aspect 10 of the present disclosure includes an operator that is displaced in accordance with a performance operation, a reactant including a metal piece or a passive coil provided on the operator, a first circuit board circuit including a first coil that generates a magnetic field by supplying an AC signal and outputs a first detection signal with an amplitude corresponding to the distance from the reactant, a second circuit board circuit including a second coil that generates a magnetic field by supplying the AC signal and outputs a second detection signal with an amplitude corresponding to the distance from the reactant, a difference output circuit that outputs the difference between the amplitude of the first detection signal and the amplitude of the second detection signal, and an information processing circuit that outputs operation information of the operator based on the difference.

[0076] Furthermore, a displacement detection device according to another aspect of this disclosure is: A reactant including a metal piece or passive coil provided on a movable member, A circuit board including a coil that generates a magnetic field by supplying an AC signal and outputs an amplitude detection signal corresponding to the distance to the reactant, The coil is formed in a spiral shape on the substrate surface of the substrate circuit, In a plan view, part or all of the reactant is displaced in a range that overlaps with the coil. [Explanation of Symbols]

[0077] 1...Displacement detection device, 2...Operation information output device, 10...Keyboard device, 12...Key, 50...Metal piece, 61...First circuit board, 62...Second circuit board, 81, 82...Rectifier circuit, 71...Demultiplexer, 72...Multiplexer, 90...Differential output circuit, 401...Coil, 611...First coil, 612...Second coil.

Claims

1. A displacement detection device for detecting the amount of displacement of a movable member, A reactant including a metal piece or passive coil provided on the movable member, A first circuit board includes a first coil that generates a magnetic field by supplying an AC signal and outputs a first detection signal with an amplitude corresponding to the distance to the reactant, A second circuit board includes a second coil that generates a magnetic field by supplying the aforementioned AC signal and outputs a second detection signal with an amplitude corresponding to the distance to the reactant, A difference output circuit that outputs the difference between the amplitude of the first detection signal and the amplitude of the second detection signal, It has, The first coil is formed in a spiral shape on the substrate surface of the first substrate circuit, The second coil is formed in a spiral shape on the substrate surface of the second substrate circuit. The first substrate circuit and the second substrate circuit are provided spaced apart along a second vertical direction on the substrate surface. The reactant is displaced along the second direction within the range between the first substrate circuit and the second substrate circuit. Displacement detection device.

2. A displacement detection device for detecting the amount of displacement of a movable member, A reactant including a metal piece or passive coil provided on the movable member, A first circuit board includes a first coil that generates a magnetic field by supplying an AC signal and outputs a first detection signal with an amplitude corresponding to the distance to the reactant, A second circuit board includes a second coil that generates a magnetic field by supplying the aforementioned AC signal and outputs a second detection signal with an amplitude corresponding to the distance to the reactant, A difference output circuit that outputs the difference between the amplitude of the first detection signal and the amplitude of the second detection signal, It has, The movable member, the first circuit board circuit, and the second circuit board circuit are multiple sets of the above, The supply of the AC signal and the output of the difference are provided by Select and execute one of the multiple sets of the first and second circuit boards in a time-division manner. Displacement detection device.

3. The aforementioned AC signal, A demultiplexer that distributes the information to the multiple sets of first or second circuit boards in a time-division manner, The demultiplexer selects, in a time-division manner, the first detection signal from the first circuit board or the second detection signal from the second circuit board supplied with the AC signal, and outputs it to the difference output circuit. A displacement detection device according to claim 2, including the following:

4. A displacement detection device for detecting the amount of displacement of a movable member, A reactant including a metal piece or passive coil provided on the movable member, A first circuit board includes a first coil that generates a magnetic field by supplying an AC signal and outputs a first detection signal with an amplitude corresponding to the distance to the reactant, A second circuit board includes a second coil that generates a magnetic field by supplying the aforementioned AC signal and outputs a second detection signal with an amplitude corresponding to the distance to the reactant, A difference output circuit that outputs the difference between the amplitude of the first detection signal and the amplitude of the second detection signal, It has, The Q value of the first circuit board and the Q value of the second circuit board are different. Displacement detection device.

5. The first coil is formed in a spiral shape on the substrate surface of the first substrate circuit, The second coil is formed in a spiral shape on the substrate surface of the second substrate circuit. Displacement detection device according to claim 4.

6. A displacement detection method for detecting the amount of displacement of a movable member provided with a reactant including a metal piece or a passive coil, An AC signal is supplied to the first coil to generate a first detection signal with an amplitude corresponding to the distance to the reactant, and an AC signal is supplied to the second coil to generate a second detection signal with an amplitude corresponding to the distance to the reactant. The difference between the amplitude of the first detection signal and the amplitude of the second detection signal is output. The first coil is formed in a spiral shape on the substrate surface of the first circuit board, The second coil is formed in a spiral shape on the substrate surface of the second circuit board, The first substrate circuit and the second substrate circuit are provided spaced apart along a second vertical direction on the substrate surface. The reactant is displaced along the second direction within the range between the first substrate circuit and the second substrate circuit. Method for detecting displacement.

7. A control element that displaces in accordance with the playing motion, A reactant including a metal piece or passive coil provided on the operator, A first circuit board includes a first coil that generates a magnetic field by supplying an AC signal and outputs a first detection signal with an amplitude corresponding to the distance to the reactant, A second circuit board includes a second coil that generates a magnetic field by supplying the aforementioned AC signal and outputs a second detection signal with an amplitude corresponding to the distance to the reactant, A difference output circuit that outputs the difference between the amplitude of the first detection signal and the amplitude of the second detection signal, An information processing circuit that outputs operation information for the operator based on the difference, An output device for the manipulated amount of an operator having an operator.

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