Method for forming keyboard device and magnetic shield

Abstract

Magnetic shields 82a, 82b are formed from conductor patterns of a substrate 8. Hence, the magnetic shields 82a, 82b can be formed thin. Thus, even when a displacement member 7 (detection part 75) is displaced substantially in parallel with the substrate 8, key pressing information based on the increase / decrease of inductance of a coil 80 can be detected while suppressing interference of the magnetic shields 82a, 82b with the displacement of the displacement member 7. Also, even when the displacement member 7 (detection part 75) is displaced perpendicularly to the substrate 8, the key pressing information based on the increase / decrease of the inductance of the coil 80 can be detected. Thus, the degree of design freedom of a keyboard instrument 1 is increased. Further, constraints can be suppressed from being imposed on the arrangement of the substrate 8 by forming the magnetic shields 82a, 82b to be thin from the conductor patterns. This also increases the degree of design freedom of the keyboard instrument 1.

Description

Technical Field

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[0001] The present invention relates to a keyboard device and a method for forming a magnetic shield, and more particularly, to a keyboard device and a method for forming a magnetic shield that can improve the degree of freedom in design.

Background Art

[0002] For example, Patent Document 1 describes a technique in which a coil for forming a magnetic field is provided in a magnetic detection circuit 12 (substrate), and a magnet 8 is relatively displaced with respect to the magnetic detection circuit 12 (coil) when a key 2 is pressed. According to this technique, an electromotive force corresponding to the distance and speed of the magnet 8 with respect to the magnetic detection circuit 12 is generated in the coil, and thus the depth and speed of the key press (hereinafter referred to as "key press information") can be detected by the electromotive force.

[0003] In Patent Document 1, each magnetic detection circuit 12 arranged in the scale direction is partitioned (surrounded) by a shield frame 14 to suppress the interference of the magnetic fields of adjacent coils. By suppressing such magnetic field interference, the key press information of each key 2 can be accurately detected.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the conventional technology described above, the shield frame 14 is formed as a wall rising from the magnetic detection circuit 12. Therefore, in order to detect key press information based on the displacement of the magnet 8, the magnet 8 must be displaced perpendicularly (up and down) to the magnetic detection circuit 12. Consequently, for example, the magnet 8 cannot be displaced parallel to the magnetic detection circuit 12 (horizontally), which tends to impose constraints on the structure of the keyboard device. In addition, it is necessary to secure space for the shield frame 14 rising from the magnetic detection circuit 12, which also tends to impose constraints on the structure of the keyboard device. In other words, although the conventional technology described above can suppress interference between the magnetic fields of adjacent coils by providing the shield frame 14, it has the problem of having little design freedom for the keyboard device.

[0006] This invention was made to solve the above-mentioned problems and aims to provide a keyboard device and a method for forming a magnetic shield that can improve the degree of design freedom. [Means for solving the problem]

[0007] To achieve this objective, the keyboard device of the present invention comprises a plurality of displacement members arranged in the scale direction and displaced in accordance with the player's operation, and a substrate having coils that generate a magnetic field for detecting the displacement of the plurality of displacement members, wherein the substrate comprises a plurality of coils provided for each of the plurality of displacement members, and magnetic shields that separate the plurality of coils from each other and are formed by conductive patterns on the substrate.

[0008] The present invention provides a method for forming a magnetic shield in a keyboard device, comprising: a plurality of displacement members arranged in the scale direction and displaced in accordance with the operation of a performer; and a substrate having a coil that generates a magnetic field for detecting the displacement of the plurality of displacement members, wherein the substrate comprises a plurality of coils provided for each of the plurality of displacement members and a magnetic shield that separates the plurality of coils, and the magnetic shield is formed by a conductive pattern on the substrate. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view of the keyboard device of the first embodiment. [Figure 2] (a) is a partially enlarged cross-sectional view of the keyboard mechanism in section IIa of Figure 1, and (b) is a partially enlarged cross-sectional view of the keyboard mechanism along the line IIb-IIb in Figure 2(a). [Figure 3] (a) is a partially enlarged cross-sectional view of the substrate in part IIIa of Figure 2(b), and (b) is a top view of the substrate as seen in the direction of arrow IIIb in Figure 3(a). [Figure 4] (a) is a partially enlarged cross-sectional view of the substrate of the second embodiment, (b) is a partially enlarged cross-sectional view of the substrate of the third embodiment, and (c) is a partially enlarged cross-sectional view of the substrate of the fourth embodiment. [Figure 5] (a) is a top view of the substrate of the fifth embodiment, and (b) is a top view of the substrate of the sixth embodiment. [Figure 6] (a) is a top view of the substrate of the seventh embodiment, and (b) is a top view of the substrate of the eighth embodiment. [Modes for carrying out the invention]

[0010] The following describes preferred embodiments with reference to the attached drawings. First, the overall configuration of the keyboard device 1 of the first embodiment will be described with reference to Figure 1. Figure 1 is a cross-sectional view of the keyboard device 1 of the first embodiment. In Figure 1, the cross-section is shown as cut by a plane perpendicular to the scale direction of the keyboard device 1 (the direction in which the keys 2 are arranged). In the following description, the side closer to the performer (left side in Figure 1) will be referred to as the front side of the keyboard device 1, the opposite side (right side in Figure 1) as the rear side, and the direction in which the keys 2 are arranged (the direction perpendicular to the plane of the paper in Figure 1) will be referred to as the scale direction.

[0011] As shown in Figure 1, the keyboard device 1 is a keyboard instrument (synthesizer) equipped with multiple keys 2. Each key 2 consists of multiple white keys 2a (52 in this embodiment) for playing diatonic notes and multiple black keys 2b (36 in this embodiment) for playing derived notes, and these multiple white keys 2a and black keys 2b are arranged in the scale direction (perpendicular to the plane of the paper in Figure 1). In this embodiment, a total of 88 keys 2 are provided, but configurations with 76 or 61 keys 2 are also acceptable.

[0012] The keyboard device 1 includes a base plate 3 for supporting the white keys 2a and black keys 2b. The base plate 3 is formed from synthetic resin, wood, steel plate, etc., into a flat plate extending in the scale direction, and the chassis 4 is supported on the upper surface of this base plate 3.

[0013] The chassis 4 comprises a pair of legs 40 spaced apart at a predetermined distance in the front-to-back direction (left-to-right direction in Figure 1), and a support portion 41 connecting the upper ends of the pair of legs 40 front to back. The legs 40 and the support portion 41 are integrally formed using synthetic resin, wood, steel plate, etc., and a support member 5 for rotatably supporting the key 2 is provided on the upper surface of the rear end side (right side in Figure 1) of the support portion 41.

[0014] The following describes the support structure for the white keys 2a by the support member 5 and the structure for rotating the displacement member 7 by the white keys 2a, but these structures are substantially the same for the black keys 2b.

[0015] The support member 5 comprises a mounting portion 50 attached to the upper surface of the chassis 4 (support portion 41), a wall portion 51 rising upward from the mounting portion 50, and a cylindrical shaft portion 52 formed on the upper end side of the wall portion 51. Each of these portions 50 to 52 is integrally formed using a resin material (synthetic resin).

[0016] Although not shown in the diagram, the mounting portion 50 is formed in a plate shape extending in the scale direction, and multiple wall portions 51 are arranged on this mounting portion 50 in the scale direction. Between these multiple wall portions 51, the rear end portion of the white key 2a is rotatably supported by the shaft portion 52.

[0017] On the upper surface of the front end side (the left end in FIG. 1) of the attached portion 50, a cylindrical holding wall 53 for holding the coil spring 6 is formed, and a plurality of holding walls 53 are arranged in the scale direction. At the central portion on the inner peripheral side of each holding wall 53, a conical convex portion 54 protruding upward is formed.

[0018] On the lower surface of the white key 2a, a recess 20 is formed at a position facing the holding wall 53 vertically, and on the inner peripheral side of this recess 20, a conical convex portion 21 protruding downward is formed. The coil spring 6 is sandwiched from above and below by the convex portion 54 of the support member 5 and the convex portion 21 of the white key 2a, so that the coil spring 6 is held on the inner peripheral sides of the holding wall 53 and the recess 20.

[0019] When the white key 2a is pressed, the elastic force of this coil spring 6 gives a key-pressing feel. On the other hand, when the white key 2a is released after being pressed, the white key 2a returns to the initial position by the elastic restoring force of the coil spring 6. At the time of such key-pressing and key-releasing, the displacement member 7 interlocks with the rotation of the white key 2a around the shaft portion 52, and the displacement of this displacement member 7 is detected by the coil 80 (see FIG. 2) of the substrate 8.

[0020] A detailed configuration for detecting the displacement of this displacement member 7 will be described with reference to FIG. 2. FIG. 2(a) is a partially enlarged cross-sectional view of the keyboard device 1 in the IIa portion of FIG. 1, and FIG. 2(b) is a partially enlarged cross-sectional view of the keyboard device 1 along the line IIb-IIb of FIG. 2(a). In FIG. 2(b), the illustration of some components (such as the white key 2a and the bottom plate 3) is omitted, only the main part of the keyboard device 1 is illustrated, and the hatching of the substrate 8 is omitted.

[0021] As shown in FIG. 2, a plate-shaped substrate 8 extending in the scale direction (the left-right direction in FIG. 2(b)) is fixed to the bottom plate 3, and a plurality of coils 80 are arranged in the scale direction on the substrate 8. Although details will be described later, the coil 80 generates a magnetic field for detecting the displacement of the displacement member 7 provided for each of the plurality of keys 2.

[0022] Above each coil 80, a displacement member 7 is rotatably supported by a holder 9. The holder 9 includes a mounting portion 90 that is attached to the upper surface of the substrate 8, and the mounting portion 90 is formed in a plate shape that extends in the scale direction.

[0023] Multiple wall portions 91 rise upward from the mounting portion 90, aligned in the scale direction, and a cylindrical shaft portion 92 for pivotally supporting the displacement member 7 is formed at the upper end of each wall portion 91. These portions 90-92 of the holder 9 are integrally formed using a resin material (synthetic resin).

[0024] Multiple through holes 93 are formed in the mounting portion 90, aligned in the scale direction, and these multiple through holes 93 are formed at positions corresponding to each coil 80. From each of the pair of wall portions 91 facing each other across the through holes 93, a shaft portion 92 protrudes toward the other, and an insertion hole 70 for inserting the shaft portion 92 penetrates the displacement member 7 in the scale direction. Although not shown in the figures, by elastically deforming the wall portion 91 (mounting portion 90) and widening the distance between the opposing shaft portions 92, it is possible to insert the shaft portion 92 into the insertion hole 70 of the displacement member 7. This shaft portion 92 allows the displacement member 7 to rotatably support itself in a position facing the coil 80 (through hole 93) vertically.

[0025] The bottom surface 71 of the displacement member 7 (the surface facing the coil 80 when it is displaced by the push key) is formed in an arc shape centered on the insertion hole 70 (shaft portion 92). At both ends of the bottom surface 71 in the rotational direction of the displacement member 7 around the shaft portion 92, the front surface 72 of the displacement member 7 facing forward in the same direction (lower left side in Figure 2(a)) and the rear surface 73 of the displacement member 7 facing backward (upper right side in Figure 2(a)) are connected. A groove 74 extends linearly from the rear surface 73 of the displacement member 7 toward the forward side in the direction of displacement of the displacement member 7 (lower left side in Figure 2(a)).

[0026] A projection 22 protrudes downward from the underside of the white key 2a, and a cylindrical guide pin 23 protrudes in the scale direction from the side of the projection 22. These projections 22 and guide pins 23 are formed integrally with the white key 2a, but it is also possible to form the projections 22 and guide pins 23 separately from the white key 2a (by fitting the projections 22 onto the white key 2a).

[0027] The guide pin 23 is slidably engaged with the groove 74 of the displacement member 7, and the groove 74 extends so as to intersect with the displacement trajectory of the guide pin 23 around the shaft portion 52 (see Figure 1). Therefore, although not shown in the illustration, when the white key 2a is pressed, the guide pin 23 rotates around the shaft portion 52 (see Figure 1), and the groove 74 is pushed in by the guide pin 23, causing the displacement member 7 to rotate around the shaft portion 92 (clockwise in Figure 2(a)).

[0028] The rotation of the displacement member 7 causes the detected portion 75, provided on the bottom surface 71 and front surface 72 of the displacement member 7, to be displaced relative to the coil 80 of the substrate 8. That is, as the stroke amount of the white key 2a increases from the state before pressing the key, the amount of intrusion of the detected portion 75 into the area facing the coil 80 (hereinafter referred to as the "detection area") increases. This amount of intrusion of the detected portion 75 is the size of the area where the detected portion 75 and the coil 80 face each other in the thickness direction of the substrate 8.

[0029] On the other hand, when the white key 2a is released, the elastic recovery force of the coil spring 6 (see Figure 1) causes the guide pin 23 to rotate around the shaft 52 (see Figure 1) to return to its initial state. This rotation of the guide pin 23 pushes up the groove 74, causing the displacement member 7 to rotate around the shaft 92 (counterclockwise in Figure 2(a)), reducing the amount the detected part 75 penetrates into the detection area.

[0030] Since the detected part 75 is a conductor formed using a conductive material (such as copper), when a current is passed through the coil 80 to generate a magnetic field, increasing the amount of penetration of the detected part 75 into the detection area decreases the inductance of the coil 80, and decreasing the amount of penetration of the detected part 75 into the detection area increases the inductance of the coil 80. Based on this increase or decrease in the inductance of the coil 80, the key press information (note information) of each key 2 is detected.

[0031] Next, the detailed configuration of the substrate 8 will be described with reference to Figure 3. Figure 3(a) is a partially enlarged cross-sectional view of the substrate 8 in part IIIa of Figure 2(b), and Figure 3(b) is a top view of the substrate 8 in the direction of arrow IIIb in Figure 3(a). Note that in Figure 3, the illustration of the resist covering the coil 80 and magnetic shields 82a and 82b is omitted, and the cross-sectional structure of the substrate 8 is schematically illustrated. Also, in Figure 3(a), dot-shaped hatching is applied to the cross-sections of the coil 80 and magnetic shields 82a and 82b, and in Figure 3(b), dot-shaped hatching is applied to the formation area of ​​the magnetic shield 82a when the substrate 8 is viewed from above. The same applies to the second to eighth embodiments (Figures 4 to 6) described later.

[0032] As shown in Figure 3, the substrate 8 is a multilayer substrate (multilayer printed circuit board) formed by stacking multiple (three in this embodiment) laminates 81a to 81c. Of the laminates 81a to 81c, laminates 81a and 81c are stacked on the front and back surfaces of the substrate 8, and laminate 81b is stacked between them.

[0033] The coil 80 consists of a coil 80a laminated on the upper surface of the laminate 81a (the outer layer on the front side of the substrate 8), coils 80b and 80c laminated in the inner layers between each laminate 81a to 81c, and a coil 80d laminated on the lower surface of the laminate 81c (the outer layer on the back side of the substrate 8). In this embodiment, the coil 80 (coils 80a to 80d) is formed in a rectangular shape when viewed from above the substrate 8 (see Figure 3(b)), but a circular coil 80 may also be used.

[0034] When manufacturing coils 80a to 80d stacked in this manner, first, the copper foil on both sides of the laminate board 81b (a copper-clad laminate with copper foil on both sides) is etched to form coils 80b and 80c. Next, the copper foil on the laminate boards 81a and 81c (copper-clad laminates with copper foil on one side) is etched to form coils 80a and 80d, and the laminate boards 81a to 81c are stacked on top of each other so that coils 80a and 80d are placed on the front and back sides of the substrate 8. In this way, a substrate 8 is manufactured in which coils 80a to 80d (conductor layers) and laminate boards 81a to 81c (insulating layers) are stacked.

[0035] In other words, each coil 80 of the substrate 8 is formed by the conductive pattern of the substrate 8. In the following explanation, this formation by etching copper foil will be simply described as "formed by the conductive pattern of the substrate 8."

[0036] Coils 80 formed by such a conductor pattern are arranged in the scale direction (left-right direction in Figure 3), and each of these coils 80 is separated by magnetic shields 82a and 82b, which are conductors. This suppresses interference between magnetic fields of adjacent coils 80 in the scale direction. By suppressing such magnetic field interference (reducing the mutual inductance between adjacent coils 80), the key press information of each key 2 can be detected with high accuracy.

[0037] Since the magnetic shields 82a and 82b are formed by the conductive pattern of the substrate 8, similar to the coil 80, the magnetic shields 82a and 82b can be made thin. Therefore, even when the displacement member 7 (detected part 75) is displaced approximately parallel to the substrate 8 (see Figure 2), the magnetic shields 82a and 82b can suppress interference with the displacement member 7, while still detecting key press information based on the increase or decrease in the inductance of the coil 80. Furthermore, even when a configuration equivalent to the detected part 75 is provided on the key 2, as in the prior art (Japanese Utility Model Publication No. 02-111199), and the displacement member 7 (detected part 75) is displaced perpendicular to the substrate 8, key press information based on the increase or decrease in the inductance of the coil 80 can still be detected. Thus, the design flexibility of the keyboard device 1 is improved.

[0038] Furthermore, by forming the magnetic shields 82a and 82b thinly using conductive patterns, constraints on the placement of the substrate 8 can be suppressed. This also improves the design flexibility of the keyboard device 1.

[0039] Since the magnetic shields 82a and 82b are formed in an annular (square annular) shape that surrounds the entire circumference of the coil 80 when viewed from above (see Figure 3(b)), interference between the magnetic fields of adjacent coils 80 can be effectively suppressed. Therefore, key press information can be detected with high accuracy.

[0040] Here, if the current flowing through coil 80 changes, the magnetic field generated from coil 80 also changes. This change in the magnetic field of coil 80 induces currents in the conductive magnetic shields 82a and 82b surrounding coil 80. Since the magnetic fields of the magnetic shields 82a and 82b generated by these induced currents are in the opposite direction to the magnetic field of coil 80, the magnetic field of coil 80 is canceled out by the magnetic fields of the magnetic shields 82a and 82b, thereby suppressing interference between the magnetic fields of adjacent coils 80.

[0041] The magnetic fields of these magnetic shields 82a and 82b (magnetic fields that cancel out the magnetic field of coil 80) are less likely to occur when the magnetic shield 682 is connected to ground, for example, as in the sixth embodiment described later (see Figure 5(b)). This is because when the magnetic shield 682 is connected to ground, some of the induced current generated in the magnetic shield 682 flows to ground (the current remaining in the magnetic shield 682 decreases), and the strength of the magnetic field generated in the magnetic shield 682 decreases.

[0042] Furthermore, as in the sixth embodiment, if the magnetic shield 682 is formed in a broad planar shape, the path of the induced current generated in the magnetic shield 682 becomes wider. When the path of the induced current becomes wider, a weak current flows over a wide area in the magnetic shield 682, thus reducing the strength of the magnetic field of the magnetic shield 682.

[0043] In other words, in configurations such as the sixth embodiment, where the magnetic shield 682 is connected to ground or formed in a wide, planar shape, the strength of the magnetic field of the magnetic shield 682 generated by the induced current, i.e., the magnetic field that cancels out the magnetic field of the coil 80, decreases, making it easier for the magnetic fields of adjacent coils 80 to interfere with each other. As a result, the detection accuracy of the key press information decreases.

[0044] In contrast, the magnetic shields 82a and 82b of this embodiment are not connected to any circuits constituting the substrate 8, such as the ground, and adjacent magnetic shields 82a and 82b in the scale direction are not connected to each other. That is, each magnetic shield 82a and 82b is electrically floating on the substrate 8, and unlike the case where the magnetic shields 82a and 82b are connected to the ground as described above, it is possible to suppress the flow of a portion of the induced current of the magnetic shields 82a and 82b to the ground. Therefore, it is possible to suppress a decrease in the magnetic field strength of the magnetic shields 82a and 82b.

[0045] Furthermore, because the magnetic shields 82a and 82b are formed in a linear shape, the path of the induced current generated in the magnetic shields 82a and 82b can be restricted compared to when the magnetic shields 82a and 82b are formed in a broad planar shape (a strong current can be passed through a relatively narrow area). This also helps to suppress a decrease in the magnetic field strength of the magnetic shields 82a and 82b.

[0046] In other words, as in this embodiment, when the magnetic shields 82a and 82b are electrically floating and formed linearly, the magnetic fields generated by the magnetic shields 82a and 82b can appropriately cancel out the magnetic fields of the coils 80. This suppresses interference between the magnetic fields of adjacent coils 80, allowing for accurate detection of key press information. Note that "linear" means, for example, that the width dimension of the magnetic shields 82a and 82b is between 1% and 20% of the distance between the coils 80 in the scale direction.

[0047] Thus, in order to accurately detect key press information, it is important to achieve both a strong magnetic field in the coil 80 (increase its self-inductance) and suppress interference between the magnetic fields of each coil 80 (decrease their mutual inductance). Therefore, in this embodiment, four layers of coils 80a to 80d are stacked on the substrate 8, and two layers of magnetic shields 82a and 82b are also stacked on the substrate 8. This allows the magnetic field to be strengthened by the multiple layers of coils 80, while interference between the magnetic fields of the coils 80 is suppressed by the multiple layers of magnetic shields 82a and 82b. As a result, key press information can be detected with high accuracy.

[0048] When stacking multiple coils 80a to 80d and magnetic shields 82a and 82b, it is possible to provide magnetic shields 82a and 82b on all conductive layers of the substrate 8, for example. In other words, although the magnetic shields 82a and 82b in this embodiment are formed on the upper surface of laminate 81a and the lower surface of laminate 81c, it is also possible to form magnetic shields 82a and 82b in the inner layers between each laminate 81a to 81c.

[0049] However, when magnetic shields 82a and 82b were formed on all layers of the substrate 8, there was a tendency for the detection accuracy of the key press information to decrease (the mutual inductance of each coil 80 increased). This is thought to be because the induced current mentioned above generates a magnetic field in the magnetic shields 82a and 82b, and if the magnetic shields 82a and 82b are formed in too many layers, the magnetic fields of the magnetic shields 82a and 82b are more likely to interfere with the magnetic fields of adjacent coils 80.

[0050] Therefore, in this embodiment, a configuration is adopted in which magnetic shields 82a and 82b are not laminated in the inner layers between each laminate 81a to 81c. That is, the number of layers of magnetic shields 82a and 82b (2 layers) is less than the number of layers of coils 80a to 80d (4 layers). As a result, it was obtained that key press information can be detected with high accuracy (mutual inductance of each coil 80 is reduced). This is thought to be because, compared to the case in which magnetic shields 82a and 82b are provided on all layers of the substrate 8 as described above, the magnetic field due to magnetic shields 82a and 82b is less likely to interfere with the magnetic field of adjacent coils 80.

[0051] Thus, the detection accuracy of key press information is thought to be affected by the magnetic fields generated in the magnetic shields 82a and 82b. In this case, for example, as in the second embodiment described later (see Figure 4(a)), if adjacent magnetic shields 82a (magnetic shield 82b) in the scale direction are stacked on different layers, the way in which each coil 80 is affected by interference from the magnetic fields from the magnetic shields 82a and 82b will differ. Therefore, there is a possibility that variations will occur in the increase or decrease in inductance associated with key press or release in each coil 80 arranged in the scale direction.

[0052] In contrast, in this embodiment, each magnetic shield 82a aligned in the scale direction is laminated on the same layer (the upper surface of the laminated plate 81a), and each magnetic shield 82b aligned in the scale direction is also laminated on the same layer (the lower surface of the laminated plate 81c). As a result, the interference of the magnetic field from the magnetic shields 82a and 82b is uniform in each coil 80 aligned in the scale direction. Therefore, variations in the increase or decrease of inductance due to pressing or releasing the key can be suppressed in each coil 80 aligned in the scale direction.

[0053] Furthermore, as in the fifth embodiment described later (see Figure 5(a)), it is also possible to arrange through-holes with plated walls, such as through-holes 510, in the formation regions of the magnetic shields 82a and 82b. However, even in this configuration, the detection accuracy of key press information sometimes decreased. This is thought to be because the magnetic field generated in the coil 80 (or the magnetic field generated in the magnetic shields 82a and 82b by the induced current) was distorted by the through-holes 510.

[0054] Therefore, in this embodiment, a configuration is adopted in which through-holes 510 are not formed in the formation regions of the magnetic shields 82a and 82b. In addition, not only the through-holes 510, but also other holes (not shown) that make up the substrate 8 are formed in positions that do not overlap with the magnetic shields 82a and 82b. Examples of other holes that make up the substrate 8 include plain holes (through-holes without plating on the wall surface), vias (through-holes or holes that connect layers), access holes (holes (recesses) that expose lands provided in the inner layers of the substrate 8), component holes (holes for mounting components), and reference holes (through-holes for positioning the substrate 8).

[0055] By not forming holes (through-holes or recesses) in the substrate 8 that would divide the magnetic shields 82a and 82b, or cut out parts of the magnetic shields 82a and 82b, the distortion of the magnetic field of the coils 80a to 80d described above can be suppressed. Therefore, key press information can be detected with high accuracy.

[0056] Next, the second to fourth embodiments will be described with reference to Figure 4. Note that parts identical to those in the first embodiment described above are denoted by the same reference numerals, and their descriptions are omitted. Figure 4(a) is a partially enlarged cross-sectional view of the substrate 208 of the second embodiment, Figure 4(b) is a partially enlarged cross-sectional view of the substrate 308 of the third embodiment, and Figure 4(c) is a partially enlarged cross-sectional view of the substrate 408 of the fourth embodiment. Note that the magnetic shields 82a and 82b of the second to fourth embodiments have the same configuration as the magnetic shields 82a and 82b of the first embodiment, except that the layers to be laminated are different.

[0057] As shown in Figure 4(a), in the substrate 208 of the second embodiment, the first coil 80 (the left coil 80 in Figure 4(a)) is surrounded by magnetic shields 82a and 82b laminated on the outer layers of the laminates 81a and 81c. On the other hand, the adjacent second coil 80 (the right coil 80 in Figure 4(a)) is surrounded by magnetic shields 82a and 82b laminated on the inner layers between the laminates 81a and 81c. These first and second coils 80 are arranged alternately in the scale direction.

[0058] In other words, in the substrate 208 of this embodiment, adjacent magnetic shields 82a and 82b in the scale direction are stacked on different layers. Even with such magnetic shields 82a and 82b, the magnetic fields of adjacent coils 80 in the scale direction are less likely to interfere with each other.

[0059] As shown in Figure 4(b), in the substrate 308 of the third embodiment, the first coil 80 (the left coil 80 in Figure 4(b)) is surrounded by a magnetic shield 82a laminated in the inner layer between the laminates 81a and 81b, and a magnetic shield 82b laminated in the outer layer of the laminate 81c. On the other hand, the adjacent second coil 80 (the right coil 80 in Figure 4(b)) is surrounded by a magnetic shield 82a laminated in the outer layer of the laminate 81a, and a magnetic shield 82b laminated in the inner layer between the laminates 81b and 81c. These first and second coils 80 are arranged alternately in the scale direction.

[0060] In other words, in the substrate 308 of this embodiment, adjacent magnetic shields 82a and 82b in the scale direction are stacked on different layers. Such magnetic shields 82a and 82b also make it difficult for the magnetic fields of adjacent coils 80 in the scale direction to interfere with each other.

[0061] Furthermore, a combination of the stacking methods of these second and third embodiments is also acceptable (a configuration in which the stacking method of magnetic shields 82a and 82b shown in Figure 4(a) and the stacking method of magnetic shields 82a and 82b shown in Figure 4(b) are alternately repeated in the scale direction).

[0062] As shown in Figure 4(c), the substrate 408 of the fourth embodiment is a multilayer substrate formed by stacking four laminates 481a to 481d. Each of these laminates 481a to 481d is a copper-clad laminate with one side (top) covered with copper foil, and coils 80a to 80d are formed on the top surface of each laminate 481a to 481d by a conductive pattern.

[0063] Magnetic shields 82a are arranged in the scale direction on the upper surface of laminate 481a, and magnetic shields 82b are arranged in the scale direction in the inner layer between laminates 481c and 481d. That is, each magnetic shield 82a and each magnetic shield 82b arranged in the scale direction are laminated in the same layer. As a result, the interference of the magnetic field from the magnetic shields 82a and 82b is uniform in each coil 80 arranged in the scale direction.

[0064] Next, the fifth to eighth embodiments will be described with reference to Figures 5 and 6. In the first to fourth embodiments described above and the fifth to eighth embodiments described below, the same parts are denoted by the same reference numerals and their descriptions are omitted. Figure 5(a) is a top view of the substrate 508 of the fifth embodiment, and Figure 5(b) is a top view of the substrate 608 of the sixth embodiment. Figure 6(a) is a top view of the substrate 708 of the seventh embodiment, and Figure 6(b) is a top view of the substrate 808 of the eighth embodiment.

[0065] As shown in Figure 5(a), the substrate 508 of the fifth embodiment is formed by creating through-holes 510 in the substrate 8 of the first embodiment. The through-holes 510 are through-holes that penetrate through the front and back surfaces of the substrate 508, and the inner walls of the through-holes 510 are plated.

[0066] Multiple through-holes 510 are formed at the four corners and on each side (long side and short side) of the rectangular annular magnetic shield 82a (magnetic shield 82b, not shown). In this embodiment, all of the multiple through-holes 510 are arranged to interrupt the magnetic shield 82a (making the magnetic shield 82a intermittent), but this is not the only configuration. For example, some (or all) of these through-holes 510 may be arranged to cut out a portion of the magnetic shield 82a.

[0067] Even when such through-holes 510 are provided, magnetic interference between adjacent coils 80 can be suppressed by the magnetic shield 82a (magnetic shield 82b, not shown).

[0068] As shown in Figure 5(b), the substrate 608 of the sixth embodiment has a magnetic shield 682 that demarcates the coil 80 formed by a solid ground (connected to ground). Although not shown in the figure, this magnetic shield 682 is laminated on the outer layers of the front and back surfaces of the substrate 608, similar to the magnetic shields 82a and 82b of the first embodiment.

[0069] The magnetic shield 682 has multiple blanks formed to create linear gaps 683 between each coil 80 arranged in the scale direction, and the substrate 608 has multiple through-holes 510 surrounding these gaps 683. This magnetic shield 682 can also suppress interference between the magnetic fields of adjacent coils 80.

[0070] The magnetic shield 682 is formed continuously in the scale direction, except for the gaps 683 that form between it and the coils 80, and the areas where the through-holes 510 are formed. That is, each coil 80 is partitioned by the magnetic shield 682 formed from a single conductive pattern, but for example, the magnetic shield 682 may be divided into multiple parts in the scale direction. Also, the magnetic shield 682 may not be connected to ground, and the through-holes 510 may be omitted.

[0071] As shown in Figure 6(a), the substrate 708 of the seventh embodiment is modified in which, among the through-holes 510 of the substrate 608 of the sixth embodiment (see Figure 5(b)), a plurality of through-holes 510 arranged along the long side of the coil 80 are replaced with elongated through-holes 710.

[0072] The through-holes 710 are formed in pairs on either side of each coil 80 arranged in the scale direction, and each of these through-holes 710 extends in a direction perpendicular to the scale direction. Although two through-holes 710 are formed between each coil 80 arranged in the scale direction, one or more through-holes 710 may be formed between each coil 80. Furthermore, two (or more) through-holes 710 formed between each coil 80 may be connected in the scale direction.

[0073] Furthermore, if the through-hole 710 is to be a hole such as a via or access hole (one that does not penetrate the substrate 708), the hole may be formed in a continuous ring (square ring) shape to surround the coil 80.

[0074] As shown in Figure 6(b), the substrate 808 of the eighth embodiment has only the through-holes 510 along the long side of the coil 80 (see Figure 5(b)) from the through-holes 510 of the sixth embodiment formed (the other through-holes 510 are omitted), and a plurality of rectangular holes 684 are formed in the magnetic shield 682. The plurality of holes 684 are distributed substantially uniformly across the formation area of ​​the magnetic shield 682. That is, the magnetic shield 682 is a solid ground with so-called cross-hatching.

[0075] By providing cross-hatching to the magnetic shield 682, the void ratio of the magnetic shield 682 is increased compared to the sixth embodiment (see Figure 5(b)). This suppresses interference between the magnetic field of the magnetic shield 682 and the magnetic fields of each coil 80.

[0076] Although the above-described embodiments have been explained, the present invention is not limited in any way to the above embodiments, and it can be easily inferred that various improvements and modifications are possible without departing from the spirit of the present invention.

[0077] Some or all of the above embodiments may be combined with or replaced with some or all of the other embodiments. For example, the magnetic shield 682 (solid ground) of the 6th to 8th embodiments may be formed on the outer periphery of the magnetic shields 82a and 82b of the 1st and 5th embodiments, or the magnetic shields 82a and 82b of the 5th embodiment (divided by the through-hole 510) may be formed on the outer periphery of the magnetic shields 82a and 82b of the 1st embodiment.

[0078] In the above embodiments, a synthesizer was used as an example of the keyboard device 1, but it is not necessarily limited to this. For example, if the keyboard device 1 is an electronic organ, the configuration may detect the displacement of the foot pedals (operating members) due to the performer's operation based on the increase or decrease in the inductance of the coil 80. If the keyboard device 1 is an electronic piano, the configuration may detect the displacement of the three pedals (operating members) due to the performer's operation based on the increase or decrease in the inductance of the coil 80. In either configuration, the configurations relating to the magnetic shields 82a, 82b, and 682 of the above embodiments can be applied.

[0079] In the embodiments described above, the displacement of the displacement member 7 linked to the key 2 (white key 2a) was detected based on the increase or decrease in the inductance of the coil 80, but the invention is not necessarily limited to this. For example, the displacement member 7 may be omitted, and the displacement of other displacement members such as the hammer (which is linked to the key 2 and provides a tactile sensation when pressed) or the key 2 may be detected based on the increase or decrease in the inductance of the coil 80. Alternatively, for example, the displacement of the displacement member 7 linked to the hammer, the foot pedals of an electronic organ, or the three pedals of an electronic piano may be detected based on the increase or decrease in the inductance of the coil 80. In these configurations as well, the configurations relating to the magnetic shields 82a, 82b, and 682 of the embodiments described above can be applied.

[0080] In the embodiments described above, the case in which the displacement member 7 rotates around the shaft portion 92 was explained. However, the displacement member 7 may also be displaced by sliding (converting the rotation of an operating member such as the key 2 into linear motion), and the sliding displacement of the displacement member 7 may be detected based on the increase or decrease in the inductance of the coil 80.

[0081] In the embodiments described above, the method for forming the detected portion 75 has been omitted. Examples of methods for forming the detected portion 75 include attaching a metal plate to the outer surface of the displacement member 7 or plating the surface of the displacement member 7.

[0082] In the embodiments described above, we explained the case where three-layer laminates 81a to 81c or four-layer laminates 481a to 481d are stacked (the substrate is a multilayer printed circuit board), but the substrate may be single-layer, two-layer, or five-layer or more.

[0083] In the embodiments described above, a configuration was described in which the substrate 8 is directly supported by the base plate 3. However, if the base plate 3 is a conductor such as a steel plate, it is preferable to raise the substrate 8 away from the base plate 3 (for example, by supporting the substrate 8 on a synthetic resin chassis 4 so that the base plate 3 and the substrate 8 are not in contact). This suppresses the effect of the conductive base plate 3 on the magnetic field of the coil 80. Similarly, if the chassis 4 is a conductor such as a steel plate, it is preferable to support the substrate 8 on a base plate 3 made of a non-conductor such as synthetic resin or wood. This suppresses the effect of the conductive chassis 4 on the magnetic field of the coil 80.

[0084] In the first to fifth embodiments described above, the case in which the magnetic shields 82a and 82b are formed in a rectangular ring shape was explained, but the invention is not necessarily limited to this. For example, the portion of the rectangular ring magnetic shields 82a and 82b extending in the scale direction may be omitted, and each coil 80 may be demarcated by linear magnetic shields 82a and 82b extending in a direction perpendicular to the scale direction. Furthermore, a portion of the magnetic shields 82a and 82b may be curved or bent, or the magnetic shields 82a and 82b may be formed in a circular or other polygonal shape. In other words, the shape of the magnetic shields 82a and 82b can be set as appropriate as long as they can demarcate each coil 80 arranged in the scale direction, and do not necessarily have to correspond to the shape of the coils 80 (for example, a circular coil 80 may be surrounded by rectangular ring magnetic shields 82a and 82b).

[0085] Furthermore, when the magnetic shields 82a and 82b are formed in an annular shape, it is preferable to make the width dimension of the magnetic shields 82a and 82b substantially constant over their entire circumference. A substantially constant width dimension means that the minimum and maximum width dimensions of the magnetic shields 82a and 82b are within ±30% of the average width dimension over their entire circumference.

[0086] By making the width dimensions of the magnetic shields 82a and 82b constant around the entire circumference, the interference of the magnetic field from the magnetic shields 82a and 82b is uniformly received around the entire circumference of the coil 80.

[0087] However, the width dimension of the magnetic shields 82a and 82b may vary in part or all of the circumferential region of the magnetic shields 82a and 82b (for example, the width dimension of a part of the magnetic shields 82a and 82b may be narrower or wider than that of other parts).

[0088] In the first to fifth embodiments described above, the case in which each magnetic shield 82a, 82b arranged in the scale direction has the same shape (square ring), was explained, but it is not necessarily limited to this. For example, magnetic shields of different shapes, such as square rings and circular rings, may be combined to partition each coil 80.

[0089] In the first to fifth embodiments described above, the case in which the magnetic shields 82a and 82b are laminated on the same layer as one of the coils 80a to 80d was explained, but this is not necessarily the only case. For example, the magnetic shields 82a and 82b may be laminated on a different layer from the coils 80a to 80d.

[0090] In the first to fifth embodiments described above, the magnetic shields 82a and 82b are not connected to the ground (the part (layer) that serves as the reference potential for operating the electronic circuits of the substrate) or other circuits constituting the substrate, and adjacent magnetic shields 82a and 82b are not connected to each other. However, the invention is not necessarily limited to this. For example, the magnetic shields 82a and 82b may be connected to the ground, or some or all of the magnetic shields 82a and 82b arranged in the scale direction may be connected with a conductor (copper foil).

[0091] In the first to fifth embodiments described above, cases in which multiple coils 80a to 80d and magnetic shields 82a and 82b are stacked (four or two layers) were explained, but the invention is not necessarily limited to this. For example, either one or both of the coils 80a and 80d and the magnetic shields 82a and 82b may be single layers. Also, the number of layers of the coils and magnetic shields may be the same, or the magnetic shields may be stacked in more layers than the coils.

[0092] In the above 5th to 8th embodiments, the case in which through-holes 510 and 710 are formed in the substrate has been described. However, in addition to (or instead of) the through-holes 510 and 710, other holes such as plain holes, vias, access holes, component holes, or reference holes may be formed in positions that overlap with the magnetic shields 82a, 82b, and 682. Furthermore, these other holes or the through-holes 510 and 710 may be formed in the region between the coil 80 and the magnetic shields 82a, 82b, and 682. As for the manufacturing method of the holes whose inner walls are plated, known methods can be used, so a detailed explanation will be omitted. An example of a known method is to make a hole in the laminate using a cutting tool such as a drill, and then plate both sides of the laminate, including the inner surface of the hole, to form copper foil. [Explanation of Symbols]

[0093] 1 Keyboard device 7 Displacement member 8,208,308,408,508,608,708,808 circuit boards 80, 80a~80d coil 81a~81c, 481a~481d Laminate 82a Magnetic shield (first magnetic shield) 82b Magnetic shield (second magnetic shield) 682 Magnetic Shield 510,710 Through-holes (holes)

Claims

1. It comprises a plurality of displacement members arranged in the scale direction that are displaced in accordance with the performer's operation, and a substrate having a coil that generates a magnetic field for detecting the displacement of the plurality of displacement members, The keyboard device is characterized in that the substrate comprises a plurality of coils provided for each of the plurality of displacement members, and a magnetic shield that separates the plurality of coils from each other and is formed by a conductive pattern of the substrate.

2. The keyboard device according to claim 1, characterized in that a plurality of annular magnetic shields surrounding the entire circumference of the coil are arranged in the scale direction.

3. The keyboard device according to claim 2, characterized in that the plurality of magnetic shields are not connected to the circuits constituting the substrate.

4. The keyboard device according to claim 2, characterized in that no holes are formed in the substrate at the location where the magnetic shield is formed.

5. The substrate is a multilayer substrate in which multiple laminates are stacked, The keyboard device according to claim 1, characterized in that the coil and the magnetic shield are stacked together with the laminated plate in multiple layers.

6. The keyboard device according to claim 5, characterized in that the number of layers of the magnetic shield is less than the number of layers of the coil.

7. The magnetic shield comprises a first magnetic shield and a second magnetic shield laminated below the first magnetic shield. Multiple of the first magnetic shields, arranged in the scale direction, are stacked in the same layer. The keyboard device according to claim 1, characterized in that a plurality of the second magnetic shields, which are arranged in the scale direction, are stacked in the same layer.

8. The magnetic shield comprises a first magnetic shield and a second magnetic shield laminated below the first magnetic shield. The first magnetic shields adjacent to each other in the scale direction are stacked in different layers, The keyboard device according to claim 1, characterized in that adjacent second magnetic shields in the scale direction are laminated in different layers.

9. A method for forming a magnetic shield in a keyboard device comprising: a plurality of displacement members arranged in the scale direction and displaced in accordance with the player's operation; a substrate having a coil that generates a magnetic field for detecting the displacement of the plurality of displacement members, wherein the substrate comprises a plurality of the coils provided for each of the plurality of displacement members; and a magnetic shield that separates the plurality of coils from each other, A method for forming a magnetic shield, characterized in that the magnetic shield is formed by the conductive pattern on the substrate.

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