Position detection sensor

Abstract

Provided is a position detection sensor including a loop coil improved so that electromagnetic coupling with an electronic pen can be made more uniform at each position between one end portion and the other end portion separated by a prescribed distance at a loop part.　The loop coil comprises a loop part, a first lead-out part connected to one end portion of the loop part, and a second lead-out part connected to the other end portion of the loop part. The one end portion and the other end portion of the loop part are separated from each other by a prescribed distance without conductor portions thereof overlapping. A portion of the first lead-out part on the side connected to the one end portion of the loop part and a portion of the second lead-out part on the side connected to the other end portion of the loop part intersect each other in an electrically insulated state.

Description

Position detection sensor

[0001] This invention relates to a position detection sensor using an electromagnetic induction method.

[0002] A position detection device using an electromagnetic induction method that is used together with a pen-type position indicator has been widely spread. In this electromagnetic induction type position detection device, a position detection sensor detects an indicated position by a position indicator by electromagnetic coupling with the pen-type position indicator. The position indicator includes a resonance circuit composed of a coil and a capacitor for electromagnetic coupling with the position detection sensor, and the position detection sensor includes one or more loop coils that electromagnetic-couple with the resonance circuit of this position indicator (see, for example, Japanese Patent Application Laid-Open No. 2016-29519).

[0003] The loop coil includes a loop portion and two lead-out portions derived from, for example, one end portion which is, for example, the start end of this loop portion and the other end portion which is, for example, the end end. Generally, one end portion and the other end portion of the loop portion are separated by a predetermined distance, and it is open between one end portion and the other end portion of the loop portion.

[0004] An example of a loop coil in a position detection sensor having, for example, a rectangular detection region is shown in FIG. 7. In this example, as shown in FIG. 7, the loop coil 10 has a rectangular loop portion 11, a first lead-out portion 12 derived from one end portion 11a of this loop portion 11, and a second lead-out portion 13 derived from the other end portion 11b of the loop portion 11. The loop coil 10 in the example of FIG. 7 is a case of a two-turn loop coil.

[0005] As shown in FIG. 7, one end portion 11a and the other end portion 11b are provided on the long side portion of the rectangular loop portion 11, and it is separated by a predetermined distance d between the one end portion 11a and the other end portion 11b. And the first lead-out portion 12 and the second lead-out portion 13 are derived as straight portions in a state orthogonal to the long side of the loop portion 11 from one end portion 11a and the other end portion 11b.

[0006] Japanese Patent Application Laid-Open No. 2016-29519

[0007] As described above, conventionally, as shown in Figure 7, the loop coil 10 has a predetermined distance d between one end 11a and the other end 11b of the loop portion 11 (open portion).

[0008] Furthermore, it was found that in the open portion between one end 11a and the other end 11b of the loop portion 11, where there is a predetermined distance d, non-uniformity occurs in the electromagnetic coupling with the coil of the resonant circuit of the electromagnetic induction type electronic pen.

[0009] In other words, as shown in Figure 7, when the magnetic core 15 around which the coil 14 of an electromagnetic induction electronic pen is wound is brought close to an open portion at a predetermined distance d between one end 11a and the other end 11b of the loop portion 11 of the loop coil 10, it was found that the impedance (mutual inductance) of the loop coil 10 becomes non-uniform in the open portion as shown in Figure 8.

[0010] In Figure 8, the horizontal axis represents the positions of the magnetic core 15 around which the coil 14 is wound, in the open portion of the loop coil 10, and the vertical axis represents the impedance of the loop coil 10.

[0011] In the position detection device, the position indicated by the electronic pen is detected based on the level of the signal induced in the loop coil 10 in response to the electromagnetic coupling between the loop coil 10 and the coil of the electronic pen. Therefore, in the open portion of the loop coil 10 where non-uniformity occurs as shown in Figure 8, the problem arises that the indicated position cannot be accurately detected.

[0012] The purpose of this invention is to provide a position detection sensor that can solve the above-mentioned problems.

[0013] To solve the above problems, the present invention provides an electromagnetic induction type position detection sensor composed of a loop coil, wherein the loop coil comprises a loop portion, a first lead portion connected to one end of the loop portion, and a second lead portion connected to the other end of the loop portion, the one end and the other end of the loop portion are separated by a predetermined distance without the conductor portions overlapping, and the portion of the first lead portion connected to the one end of the loop portion and the portion of the second lead portion connected to the other end of the loop portion intersect in an electrically insulated state.

[0014] In the invention with the above configuration, the portion of the first extension that connects to one end of the loop and the portion of the second extension that connects to the other end of the loop intersect, so that a conductor exists between the one end and the other end of the loop, resulting in a shape that is close to an ideally closed coil. As a result, it is possible to provide a position detection sensor equipped with a loop coil that can make the electromagnetic coupling with the electronic pen more uniform at each position between the one end and the other end of the loop that are separated by a predetermined distance.

[0015] According to this invention, it is possible to provide a position detection sensor equipped with an improved loop coil that can make the electromagnetic coupling with the electronic pen more uniform at each position between one end and the other end of the loop that are separated by a predetermined distance.

[0016] This figure shows an example of the configuration of a loop coil in an embodiment of the position detection sensor according to this invention. This figure illustrates an example of the configuration of a loop coil in an embodiment of the position detection sensor according to this invention. This is a characteristic diagram illustrating the electromagnetic coupling of the loop coil in an embodiment of the position detection sensor according to this invention with an electronic pen. This figure illustrates a comparative example of the loop coil in an embodiment of the position detection sensor according to this invention. This figure illustrates another example of the configuration of the loop coil in an embodiment of the position detection sensor according to this invention. This figure illustrates yet another example of the configuration of the loop coil in an embodiment of the position detection sensor according to this invention. This figure shows an example of the configuration of a loop coil in a conventional position detection sensor. This is a characteristic diagram illustrating the electromagnetic coupling of the loop coil in the example of Figure 7 with an electronic pen.

[0017] Hereinafter, an embodiment of the position detection sensor according to this invention will be described with reference to the figures.

[0018] The position detection sensor in this embodiment is constructed by arranging a plurality of loop coils at predetermined intervals in the X-axis and Y-axis directions on a substrate made of an insulating material. Known methods for forming loop coils on this substrate include a wire laying method and an etching method.

[0019] The wire laying method, as described in Patent Document 1 (Japanese Patent Publication No. 7-253840), involves forming a loop coil by laying insulated copper wire (coated copper wire) in a predetermined pattern, thereby forming a position detection sensor. The position detection sensor in the embodiment described below is one in which the loop coil is formed using this wire laying method.

[0020] Figure 1 shows a loop coil 100 that constitutes the position detection sensor of this embodiment. The loop coil 100 in the example of Figure 1 is a two-turn coil made of insulated copper wire, and in this example it comprises a rectangular loop portion 101, a first lead portion 102 connected to one end 101a of the loop portion 101, and a second lead portion 103 connected to the other end 101b of the loop portion 101. Note that one end 101a and the other end 101b of the loop portion 101 are indicated by reference numerals to explain the loop coil 100 of this embodiment, and in practice the loop portion 101 and the first lead portion 102 and the second lead portion 103 are connected by a single insulated copper wire. In this embodiment of the loop coil 100, one end 101a and the other end 101b of the loop portion 101 are bent portions of the coated copper wire at the positions where the loop portion 101 changes to the first lead portion 102 and the second lead portion 103.

[0021] In the loop coil 100 of this embodiment, the space between one end 101a and the other end 101b of the loop portion 101 is an open portion separated by a predetermined distance d0 without the insulated copper wires overlapping.

[0022] In this embodiment, the portion of the first extension 102 that connects to one end 101a of the loop 101 is designated as the first intersection 102a. This first intersection 102a is arranged linearly in a direction having a predetermined acute angle θ1 (see Figure 2) with respect to the direction from one end 101a to the other end 101b of the loop 101, so that it intersects with the portion of the second extension 103 that connects to the other end 101b of the loop 101 (the second intersection 103a, which will be described later).

[0023] Furthermore, the first extension portion 102 has a first extension portion 102b that is bent from the first intersection portion 102a at a predetermined angle with respect to the first intersection portion 102a and then extends linearly in this example. In this embodiment, the first extension portion 102b is formed in a direction perpendicular to the long side direction, which includes one end 101a and the other end 101b of the loop portion 101.

[0024] Furthermore, the second lead-out portion 103 has a second intersection portion 103a at the end 101b of the loop portion 101. This second intersection portion 103a is arranged linearly in a direction having a predetermined acute angle θ2 (see Figure 2) with respect to the direction from the other end 101b of the loop portion 101 toward the one end 101a, and intersects with the first intersection portion 102a of the first lead-out portion 102. In this example, the loop coil 100 is made of coated copper wire, so even at the intersection where the first intersection portion 102a and the second intersection portion 103a overlap, the two are electrically insulated from each other.

[0025] The second extension portion 103 is bent from the second intersection portion 103a at a predetermined angle to the second intersection portion 103a, and in this example, has a second extension portion 103b that extends in a straight line. In this embodiment, the second extension portion 102b is formed in a direction perpendicular to the long side direction, which includes one end 101a and the other end 101b of the loop portion 101.

[0026] Therefore, in this embodiment, the first extension 102b of the first extension 102 and the second extension 103b of the second extension 103 are arranged to be parallel to each other and extend in the same direction, as shown in Figures 1 and 2. Furthermore, in this example, the first extension 102b of the first extension 102 and the second extension 103b of the second extension 103 are arranged to maintain the distance d0 between one end 101a and the other end 101b of the loop 101, as shown in Figures 1 and 2.

[0027] The distance d0 is selected as the distance separating the first extension 102b and the second extension 103b in order to enable good signal transmission and reception when transmitting a signal to the electronic pen and receiving a signal from the electronic pen through electromagnetic coupling between the loop coil 100 and the coil of the electronic pen.

[0028] In this embodiment, the angle θ1 formed between the first intersection 102a of the first extension portion 102 and the direction of the longer side of the loop portion 101, and the angle θ2 formed between the second intersection 103a of the second extension portion 103 and the direction of the longer side of the loop portion 101, may be different, but in this embodiment, they are set to a predetermined angle θ0 (θ0 = θ1 = θ2) which is equal to each other. Therefore, as shown by the dotted line in Figure 2, the triangle formed with the line segment connecting one end 101a and the other end 101b of the loop portion 101 as the base and the intersection point of the first intersection 102a and the second intersection 103a as the vertex is an isosceles triangle.

[0029] Thus, in the loop coil 100 of this embodiment, the first intersection 102a of the first lead portion 102 and the second intersection 103a of the second lead portion 103 intersect, so that a conductor exists between one end 101a and the other end 101b of the loop portion 101, resulting in a shape that is close to an ideally closed loop coil. As a result, it is possible to obtain a loop coil that can make the uneven electromagnetic coupling with the electronic pen more uniform at each position between the one end and the other end of the loop portion of the loop coil 100, which are separated by a predetermined distance.

[0030] In this embodiment, the angle θ0 is set to a value in the range of 0 < θ0 < 45°. In the loop coil 100 of this embodiment, Figure 3 shows the impedance of the loop coil 100 when a magnetic core 105 around which the coil 104 of an electromagnetic induction type electronic pen is wound is brought close to an open portion at a predetermined distance d0 between one end 101a and the other end 101b of the loop portion 101, as shown in Figure 1.

[0031] In Figure 3, the horizontal axis represents the positions of the magnetic core 105 around which the coil 104 is wound, within the open portion of the loop coil 100, and the vertical axis represents the impedance of the loop coil 100. In Figure 3, the dotted line 111 shows the impedance change of the loop coil 10 having an open portion, as explained in Figure 7, and is similar to that shown in Figure 8, and is for comparison with the case of the loop coil 100 in this embodiment.

[0032] In Figure 3, the dashed line 112 shows the impedance change of the loop coil 100 when the angle θ0 = 45°, and the solid line 113 shows the impedance change of the loop coil 100 when the angle θ0 = 20°.

[0033] Figure 3 shows that, according to this embodiment, the loop coil 100 is more uniform at each position between one end 101a and the other end 101b of the loop portion 101 compared to the loop coil 10 having an open portion as described in Figure 7.

[0034] In particular, in the case of the angle θ0 = 20° as described above, the loop coil 100 is found to be almost uniform at each position between one end 101a and the other end 101b of the loop portion 101, as shown by the solid line 113 in Figure 3. Therefore, by setting the angle θ0 in the loop coil 100 to 20° or a value close to it, it is possible to realize a loop coil that can make the non-uniform electromagnetic coupling with the electronic pen uniform.

[0035] Furthermore, in order to construct a closed loop section that eliminates the open section between one end and the other end of the loop coil, it is possible to overlap copper wires between one end and the other end of the loop coil, as shown in Figure 4. In the example loop coil 200 in Figure 4, a single-turn loop section 201 is constructed using insulated copper wire, and one end 201a and the other end 201b of the loop section 201 are separated by a distance d0.

[0036] In the example of the loop coil 200 in Figure 4, a first lead-out portion 202 is provided that is connected to one end 201a of the loop portion 201. The first lead-out portion 202 comprises a first overlapping portion 202a equal to the distance d0 between one end 201a and the other end 201b of the loop portion 201, and a first extension portion 202b that extends from the first overlapping portion 202a in a direction perpendicular to the first overlapping portion 202a.

[0037] Furthermore, in the example of the loop coil 200 in Figure 4, a second lead-out portion 203 is provided that is connected to the other end 201b of the loop portion 201. The second lead-out portion 203 comprises a second overlapping portion 203a equal to the distance d0 between the other end 201a and the one end 201b of the loop portion 201, and a second extension portion 203b that extends from the second overlapping portion 203a in a direction perpendicular to the second overlapping portion 203a.

[0038] The loop coil 200 in the example of Figure 4 corresponds to the case where the angle θ0 = 0° is set in the loop coil 100 of this embodiment shown in Figure 1.

[0039] In the example of the loop coil 200 in Figure 4, when a magnetic core 105 with the coil 104 of an electromagnetic induction type electronic pen wound around it is brought close to the portion of the loop coil 200 at a predetermined distance d0 between one end 201a and the other end 201b of the loop portion 201, the change in the impedance of the loop coil 200 is as shown by the dashed line 114 in Figure 3. That is, it was found that the impedance is non-uniform at each position at the distance d0. This is thought to be because there are two overlapping copper wires at the distance d0.

[0040] In contrast, in the loop coil 100 of this embodiment, the distance d0 portion has first intersections 102a and 103a that intersect at a predetermined angle, and there are no overlapping copper wires. As described above, compared to the case where the distance d0 portion is open, a loop coil with a more uniform impedance at each position in the distance d0 portion can be realized.

[0041] [Other Embodiments or Modifications] In the above description of the embodiment, the position detection sensor was assumed to be configured by arranging a plurality of loop coils at predetermined intervals in the X-axis and Y-axis directions on a substrate made of an insulating material. However, the number of loop coils in the position detection sensor may be one. Furthermore, when the position detection sensor has a plurality of loop coils, they may be arranged at predetermined intervals only in the X-axis direction or the Y-axis direction.

[0042] Also, although the loop coil of the above-described embodiment was formed by a wire wiring method using a coated copper wire, this invention is also applicable to the case of a loop coil formed by an etching method of forming a predetermined conductor pattern on an insulating substrate. In this case, one of the first intersection connected to one end of the loop coil and one of the second intersections connected to the other end are formed on the front surface of the insulating substrate, and the other is formed on the back surface, so that the first intersection and the second intersection are configured to intersect while maintaining an insulating state.

[0043] FIG. 5 shows an example of a loop coil formed by an etching method. The loop coil 300 in this example is configured by forming conductive patterns on the front and back of an insulating substrate 310. Also in the loop coil 300 of this example, as shown in FIG. 5, it has a rectangular loop portion 301, a first lead portion 302 connected to one end 301a of the loop portion 301, and a second lead portion 303 connected to the other end 301b of the loop portion 301. And also in the loop coil 300 of this example, as shown in FIG. 5, the first lead portion 302 has a first intersection 302a and a first extension portion 302b, and the second lead portion 303 has a second intersection 303a and a second extension portion 303b.

[0044] And in the loop coil 300 of this example, the long side portion shown by the solid line of the loop portion 301 is formed on the front surface of the insulating substrate 310, and the short side portion shown by the dotted line is formed on the back surface of the insulating substrate 310. The long side portion and the short side portion of the loop portion 301 are electrically connected through through-holes 311, 312, 313, 314 provided in the insulating substrate 310. In FIG. 5, the conductor pattern on the back side is shown by a dotted line.

[0045] And in the example of FIG. 5, the first intersection portion 302a of the first lead portion 302 is formed on the front surface side of the insulating substrate 310, and the first extension portion 302b is electrically connected to the first intersection portion 302a through the through hole 315 and is formed on the back surface side of the insulating substrate 310. Further, the second intersection portion 303a of the second lead portion 303 is electrically connected to the other end portion 301b of the loop portion 301 through the through hole 316 and is formed on the back surface side of the insulating substrate 310. Then, the second extension portion 303 is formed by connecting to the second intersection portion 303a on the back surface side of the insulating substrate 310.

[0046] In the loop coil of the above-described embodiment, the first intersection portion of the first lead portion and the second intersection portion of the second lead portion are arranged outside the loop of the loop portion. However, they may be configured to be arranged inside the loop of the loop portion.

[0047] The loop coil 400 in FIG. 6 shows an example in such a configuration. The first intersection portion 402a of the first lead portion 402 connected to one end portion 401a of the loop portion 401 is provided in a direction that is inside the loop of the loop portion 401. Also, the second intersection portion 403a of the second lead portion 403 connected to the other end portion 401b of the loop portion 401 is also provided in a direction that is inside the loop of the loop portion 401, and the first intersection portion 402a and the second intersection portion 403a are configured to intersect.

[0048] And the first extension portion 402b of the first lead portion 402 and the second extension portion 403b of the second lead portion 403 are each extended from the first intersection portion 402a of the first lead portion 402 and the second extension portion 403a of the second lead portion 403 in a direction orthogonal to the long side direction of the loop portion 401, and in the example of FIG. 6, they are arranged to intersect in a state of being electrically insulated from the long side of the loop portion 401.

[0049] The loop coil 400 in the example of FIG. 6 also has the same operational effects as the loop coil 100 of the above-described embodiment.

[0050] In the above embodiment, the loop portion was given a rectangular shape, but it goes without saying that the shape of the loop portion is not limited to a rectangle.

[0051] 100, 200, 300, 400... Loop coil, 101, 201, 301, 401... Loop section, 101a, 201a, 301a, 401a... One end of loop section 101, 201, 301, 401, 101b, 201b, 301b, 401b... The other end of loop section 101, 201, 301, 401, 102, 202, 302, 402... First lead section, 103, 203, 303, 403... Second extension section, 102a, 302a, 402a... First intersection section, 102b, 202b, 302b, 402b... First extension section, 103a, 303a, 403a... Second intersection section, 103b, 203b, 303b, 403b... Second extension section, 310... Insulating substrate, 311, 312, 313, 314, 315, 316... Through-hole

Claims

1. An electromagnetic induction type position detection sensor comprising a loop coil, wherein the loop coil comprises a loop portion, a first lead portion connected to one end of the loop portion, and a second lead portion connected to the other end of the loop portion, wherein the one end and the other end of the loop portion are separated by a predetermined distance without overlapping conductor portions, and the portion of the first lead portion connected to the one end of the loop portion and the portion of the second lead portion connected to the other end of the loop portion intersect in an electrically insulated state.

2. The position detection sensor according to claim 1, characterized in that the portion of the first extension that connects to one end of the loop portion and the portion of the second extension that connects to the other end of the loop portion intersect at a predetermined angle.

3. The position detection sensor according to claim 2, characterized in that the portion of the first extension that connects to one end of the loop portion and the portion of the second extension that connects to the other end of the loop portion intersect in a manner that forms an isosceles triangle with the line segment connecting the one end and the other end of the loop portion as the base and the point of intersection as the vertex.

4. The position detection sensor according to claim 1, characterized in that the portion of the first extension that connects to one end of the loop is arranged in a direction having a predetermined acute angle with respect to the direction from one end of the loop to the other end, so as to intersect with the portion of the second extension that connects to the other end of the loop.

5. The position detection sensor according to claim 1, characterized in that the portion of the second extension that connects to the other end of the loop is arranged in a direction having a predetermined acute angle with respect to the direction from the other end of the loop toward the one end, so as to intersect with the lead portion of the first extension that comes out from the one end of the loop.

6. The position detection sensor according to claim 4, characterized in that the first extension portion has a first intersection portion on the side of the loop portion that connects to one end of the loop portion, and a first extension portion that extends from the first intersection portion at a predetermined angle with respect to the first intersection portion.

7. The position detection sensor according to claim 5, characterized in that the second extension portion has a second intersection portion on the side of the loop portion that connects to the other end portion, and a second extension portion that extends from the second intersection portion at a predetermined angle with respect to the second intersection portion.

8. The position detection sensor according to claim 1, characterized in that the first extension portion has a first intersection portion on the side of the loop portion that connects to one end of the loop portion, and a first extension portion that extends from the first intersection portion at a predetermined angle with respect to the first intersection portion, and the second extension portion has a second intersection portion that is on the side of the loop portion that connects to the other end of the loop portion and intersects with the first intersection portion, and a second extension portion that extends from the second intersection portion at a predetermined angle with respect to the second intersection portion.

9. The position detection sensor according to claim 9, characterized in that the first extension and the second extension are parallel to each other and spaced apart by the predetermined distance.

10. The position detection sensor according to claim 1, characterized in that the loop coil is made of coated copper wire.

11. The position detection sensor according to claim 8, wherein the loop coil is formed as a conductive pattern on a substrate, and one of the first intersection of the first lead portion and the second intersection of the second lead portion is formed on the surface of the substrate, and the other is formed on the back surface of the substrate.

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