Capacitive sensor

Abstract

The present invention enables simplification of a structure in which a plurality of sensor elements are formed in the same sheet shape.　A capacitive sensor (1) comprises a first sensor (11) and a second sensor (12), each of the first sensor (11) and the second sensor (12) comprising, at least, a ground layer (51), a dielectric layer (20, 40), and a voltage application layer (22, 42), which are stacked on one another. The first sensor (11) and the second sensor (12) overlap in a partial region in a planar direction, and have the ground layer (51) in common.

Description

Capacitive Sensor

[0001] The present invention relates to a capacitance type sensor.

[0002] A known torsion sensor detects torsional strain applied to a detection object, such as a rod. A capacitance sensor includes a capacitance section obtained by forming a pair of electrode layers on the surface of a dielectric layer. In a capacitance sensor used as a torsion sensor, the capacitance section detects a change in capacitance due to torsion of the detection object (see, for example, Patent Documents 1 and 2).

[0003] Patent No. 4242977 Patent No. 5907220

[0004] In order to use a capacitance sensor to detect the torsion of an object with a high ratio of height to diameter, such as a thin round bar, the sensor elements, including the capacitance section, must be formed obliquely to the longitudinal direction (axial direction) of the object. Furthermore, to determine the direction of torsion of the object based on the capacitance value output from the capacitance sensor, two sensor elements must be arranged in intersecting directions.

[0005] However, in a capacitance sensor, when multiple sensor elements arranged in intersecting directions are attached diagonally to the object to be detected, if the sensor elements overlap each other, the thickness of the overlapping sensor elements increases. In this case, the capacitance sensor is more likely to wear out due to external forces. For this reason, when multiple sensor elements are formed on the same sheet in a capacitance sensor, a simpler stacking structure of the sensor elements is required.

[0006] Furthermore, in the case of capacitance-type sensors, when multiple sensor elements are formed on the same sheet, it is also desirable to simplify the stacked structure of the sensor elements to improve processability, or to make the sensor elements thinner to improve attachment to the object to be detected.

[0007] The present invention addresses the above-mentioned problem as an example, and aims to provide a capacitance sensor that allows for a simplified structure in which multiple sensor elements are formed on the same sheet.

[0008] In order to achieve the above object, the capacitance type sensor of the present invention is a capacitance type sensor comprising a first sensor and a second sensor, wherein the first sensor and the second sensor are each laminated with at least a ground layer, a dielectric layer, and a voltage application layer, and overlap in a partial area in the surface direction, and have the common ground layer.

[0009] In a capacitance-type sensor according to one aspect of the present invention, the first sensor has the voltage application layer, the dielectric layer, and the ground layer stacked in that order from the bottom in the stacking direction, and the second sensor has the ground layer, the dielectric layer, and the voltage application layer stacked in that order from the bottom in the stacking direction.

[0010] In one aspect of the capacitance type sensor of the present invention, the capacitance type sensor includes an insulating layer, and includes a lower insulating layer stacked below the voltage application layer in the first sensor, and an upper insulating layer stacked above the voltage application layer in the second sensor.

[0011] In the capacitance type sensor according to one aspect of the present invention, the first sensor and the second sensor each have a rectangular shape having a long side and a short side in the planar direction, and intersect in the region.

[0012] In the capacitance type sensor according to one aspect of the present invention, the first sensor and the second sensor intersect at a center portion in the longitudinal direction.

[0013] According to the capacitance type sensor of the present invention, it is possible to simplify the structure in which a plurality of sensor elements are formed on the same sheet.

[0014] 1 is a plan view schematically showing the configuration of a capacitance type sensor according to an embodiment of the present invention. FIG. 1 is an A-A cross-sectional view of the capacitance type sensor shown in FIG. 1. FIG. 2 is a B-B cross-sectional view of the capacitance type sensor shown in FIG. 1. FIG. 3 is a schematic diagram showing a capacitor equivalent to the capacitance type sensor shown in FIG. 1. FIG. 4 is a plan view showing a process of fabricating a lower insulating layer in the capacitance type sensor shown in FIG. 1. FIG. 5 is a plan view showing a process of fabricating a first voltage application layer of a first sensor in the capacitance type sensor shown in FIG. 1. FIG. 6 is a plan view showing a process of fabricating a first dielectric layer of a first sensor in the capacitance type sensor shown in FIG. 1. FIG. 7 is a plan view showing a process of fabricating ground layers of the first and second sensors in the capacitance type sensor shown in FIG. 1. FIG. 8 is a plan view showing a process of fabricating a second dielectric layer of a second sensor in the capacitance type sensor shown in FIG. 1. FIG. 9 is a plan view showing a process of fabricating a second voltage application layer of a second sensor in the capacitance type sensor shown in FIG. 1. FIG. 10 is a plan view showing a process of fabricating an upper insulating layer in the capacitance type sensor shown in FIG. 1. FIG. 11 is a schematic diagram showing an example of a capacitance measurement circuit using the capacitance type sensor shown in FIG. 1. It is a schematic diagram showing a capacitance part in a state where the capacitance sensor shown in Figure 1 is attached to a detection object. It is a plan view showing an outline of the configuration of a capacitance sensor of a comparative example. It is an A1-A1 cross-sectional view of the capacitance sensor shown in Figure 14. It is a B1-B1 cross-sectional view of the capacitance sensor shown in Figure 14.

[0015] Hereinafter, a capacitance type sensor 1 according to an embodiment of the present invention will be described with reference to the drawings.

[0016] Fig. 1 is a plan view schematically showing the configuration of a capacitance sensor 1 according to an embodiment of the present invention. Fig. 2 is a cross-sectional view of the capacitance sensor 1 taken along line A-A. Fig. 3 is a cross-sectional view of the capacitance sensor 1 taken along line B-B. Fig. 2 is a cross-sectional view mainly showing the layer structure of a first sensor 11 in the capacitance sensor 1. Fig. 3 is a cross-sectional view mainly showing the layer structure of a second sensor 12 in the capacitance sensor 1.

[0017] In the following description, the horizontal (left-right) direction in the plan view of the capacitance sensor 1 shown in FIG. 1 is defined as the x-axis direction, and the vertical (up-down) direction in the plan view of FIG. 1, which is perpendicular to the x-axis, is defined as the y-axis direction. Furthermore, in the following description, the direction perpendicular to the x-axis and y-axis, i.e., the direction penetrating the plan view of FIG. 1 (the vertical direction in FIGS. 2 and 3), is defined as the z-axis direction (height direction, stacking direction). In the following description, the horizontal, vertical, left-right, and up-down directions are based solely on the drawings of this embodiment and are not limited to the actual configuration. In the following description, the direction of the xy plane, which is a plane perpendicular to the stacking direction, is referred to as the surface direction. Furthermore, in the following description, all surfaces shown in the plan view of FIG. 1 are front surfaces, and the surfaces opposite the front surfaces are back surfaces.

[0018] 1 to 3, the capacitance sensor 1 according to this embodiment includes a first sensor 11 and a second sensor 12. The first sensor 11 and the second sensor 12 each include at least a ground layer 51, dielectric layers (first dielectric layer 20 and second dielectric layer 40), and voltage application layers (first voltage application layer 22 and second voltage application layer 42) stacked one on top of the other, which overlap in a partial area in the planar direction and share the common ground layer 51. The configuration and operation of the capacitance sensor 1 will now be described in detail.

[0019] [Configuration of First Sensor and Second Sensor] As shown in FIG. 1 , in the capacitance sensor 1, the first sensor 11 and the second sensor 12 overlap in a partial area (overlapping area 13) in the planar direction, as described above, with the second sensor 12 positioned above the first sensor 11. In FIG. 1 , the dashed lines indicate the overlapping area 13 where the first sensor 11 and the second sensor 12 overlap. Specifically, the first sensor 11 and the second sensor 12 each have a rectangular shape having a long side (long side 14) and a short side (short side 15) in the planar direction. The capacitance sensor 1 is formed in an X-shape or a substantially X-shape in plan view, with the first sensor 11 and the second sensor 12 intersecting at the overlapping area 13 located in the center of the longitudinal direction. In the capacitance sensor 1, the first sensor 11 and the second sensor 12 are integrally formed.

[0020] In the capacitance sensor 1, the overlap region 13 where the first sensor 11 and the second sensor 12 intersect is not limited to the center in the longitudinal direction as shown in FIG. 1 , and the length of one side of the overlap region 13 in the left-right direction or the up-down direction may be different from the other side. In the capacitance sensor 1, the angle at which the first sensor 11 and the second sensor 12 intersect is not limited to the angle shown in FIG. 1 . In the capacitance sensor 1, the first sensor 11 and the second sensor 12 are not limited to an X-shape or a nearly X-shape in plan view as shown in FIG. 1 , and may be formed, for example, in a V-shape or a nearly V-shape in plan view. In the capacitance sensor 1, the lengths and length ratios of the long sides 14 and short sides 15 of the first sensor 11 and the second sensor 12 are not limited to the example shown in FIG. 1 .

[0021] [Configuration of Dielectric Layer, Ground Layer, Voltage Application Layer, and Insulating Layer] FIG. 4 is a schematic diagram showing a capacitor 3 equivalent to the capacitance type sensor 1. As shown in FIG.

[0022] 2 to 4, the configurations of the first dielectric layer 20, the second dielectric layer 40, the ground layer 51, the first voltage application layer 22, the second voltage application layer 42, the lower insulating layer 23, and the upper insulating layer 24 in the capacitance sensor 1 will be described.

[0023] The first dielectric layer 20 and the second dielectric layer 40 function as the dielectric 30 in the capacitor 3 shown in Fig. 4. As described above, the first dielectric layer 20 is laminated inside (near the center of) the area surrounded by the lower insulating layer 23 and the upper insulating layer 24 in the first sensor 11, with the upper dielectric layer surface 203 facing the ground layer back surface 514 of the ground layer 51. Furthermore, the first dielectric layer 20 is laminated inside the area surrounded by the lower insulating layer 23 and the upper insulating layer 24 in the first sensor 11, with the lower dielectric layer back surface 204 facing the voltage application layer surface 223 of the first voltage application layer 22.

[0024] The second dielectric layer 40 is laminated in the second sensor 12 inside the area surrounded by the lower insulating layer 23 and the upper insulating layer 24, with the upper dielectric layer surface 403 facing the voltage application layer back surface 424 of the second voltage application layer 42. The second dielectric layer 40 is also laminated in the second sensor 12 inside the area surrounded by the lower insulating layer 23 and the upper insulating layer 24, with the lower dielectric layer back surface 404 facing the ground layer surface 513 of the ground layer 51.

[0025] The first dielectric layer 20 and the second dielectric layer 40 are sheet-like members integrally formed from an elastomer composition. The first dielectric layer 20 and the second dielectric layer 40 can be reversibly deformed to change the area of ​​their front and back surfaces. Furthermore, the first dielectric layer 20 and the second dielectric layer 40 have a relatively high relative dielectric constant, for example, 5 or more (measured at a frequency of 100 Hz). Examples of elastomer compositions include those containing an elastomer and, if necessary, other optional components such as dielectric particles. Examples of elastomers include natural rubber, isoprene rubber, nitrile rubber (NBR), ethylene propylene rubber (EPDM), styrene-butadiene rubber (SBR), butadiene rubber (BR), chloroprene rubber (CR), silicone rubber, fluororubber, acrylic rubber, hydrogenated nitrile rubber, and urethane rubber. These may be used alone or in combination.

[0026] The ground layer 51 functions as the negative electrode 31 of the capacitor 3 shown in FIG. 4 . The ground layer 51 is a layer commonly used by both the first sensor 11 and the second sensor 12, i.e., a layer shared by the first sensor 11 and the second sensor 12. Because the ground layer 51 is shared by the first sensor 11 and the second sensor 12, the ground layer 51 is laminated inside the area surrounded by the lower insulating layer 23 and the upper insulating layer 24, with the lower ground layer rear surface 514 facing the dielectric layer front surface 203 of the first dielectric layer 20 constituting the first sensor 11. Furthermore, the ground layer 51 is laminated inside the area surrounded by the lower insulating layer 23 and the upper insulating layer 24, with the upper ground layer front surface 513 facing the dielectric layer rear surface 404 of the second dielectric layer 40 constituting the second sensor 12. The ground layer front surface 513 is laminated facing the upper insulating layer rear surface 244 of the upper insulating layer 24.

[0027] The ground layer 51 is made of, for example, the above-mentioned elastomer composition containing a conductive material such as carbon black, carbon nanotubes, silver nanoparticles, or other conductive particles.

[0028] The first voltage application layer 22 and the second voltage application layer 42 function as the positive electrode 32 in the capacitor 3 shown in Fig. 4. The first voltage application layer 22 is laminated inside the area surrounded by the lower insulating layer 23 and the upper insulating layer 24, with the lower voltage application layer back surface 224 facing the lower insulating layer front surface 233 of the lower insulating layer 23. Furthermore, the first voltage application layer 22 is laminated inside the area surrounded by the lower insulating layer 23 and the upper insulating layer 24, with the upper voltage application layer front surface 223 facing the dielectric layer back surface 204 of the first dielectric layer 20 that constitutes the first sensor 11.

[0029] The second voltage application layer 42 is laminated inside the area surrounded by the lower insulating layer 23 and the upper insulating layer 24, with the lower voltage application layer back surface 424 facing the dielectric layer front surface 403 of the second dielectric layer 40 that constitutes the second sensor 12. Furthermore, the second voltage application layer 42 is laminated inside the area surrounded by the lower insulating layer 23 and the upper insulating layer 24, with the upper voltage application layer front surface 423 facing the upper insulating layer back surface 244 of the upper insulating layer 24.

[0030] The first voltage application layer 22 and the second voltage application layer 42, like the above-mentioned ground layer 51, are made of, for example, an elastomer composition containing a conductive material such as carbon black, carbon nanotubes, silver nanoparticles, or other conductive particles.

[0031] 2 and 3, the lower insulating layer 23 is provided on the lower side (outer side, the side away from the center of the first sensor 11 and the second sensor 12) of the first dielectric layer 20 in the first sensor 11. In addition, the lower insulating layer 23 is provided on the lower side of the ground layer 51 in the second sensor 12, as shown in FIG.

[0032] 2 and 3 , the upper insulating layer 24 is provided above (on the outside, away from the center of) the ground layer 51 in the first sensor 11 and the second sensor 12. In the second sensor 12, the upper insulating layer 24 is provided above the second voltage application layer 42.

[0033] The lower insulating layer 23 and the upper insulating layer 24 electrically insulate the ground layer 51 and other components from the outside. The lower insulating layer 23 and the upper insulating layer 24 also increase the strength and durability of the capacitance sensor 1. The lower insulating layer 23 and the upper insulating layer 24 may both be made of the same elastomer composition as the material constituting the first dielectric layer 20. Note that in the capacitance sensor 1, the insulating layers are not limited to those covering the upper and lower sides of the layers constituting the first sensor 11 and the second sensor 12 shown in FIGS. 2 and 3 , i.e., the first dielectric layer 20 and the second dielectric layer 40, the ground layer 51, and the first voltage application layer 22 and the second voltage application layer 42. In other words, in the capacitance sensor 1, the insulating layers may cover the side surfaces of the layers constituting the first sensor 11 and the second sensor 12.

[0034] Next, the arrangement and stacking order of the layers constituting the first sensor 11 and the second sensor 12 will be described.

[0035] FIG. 5 is a plan view showing a process for fabricating the lower insulating layer 23 in the capacitance sensor 1. FIG. 6 is a plan view showing a process for fabricating the first voltage application layer 22 of the first sensor 11 in the capacitance sensor 1. FIG. 7 is a plan view showing a process for fabricating the first dielectric layer 20 of the first sensor 11 in the capacitance sensor 1. FIG. 8 is a plan view showing a process for fabricating the ground layers 51 of the first sensor 11 and the second sensor 12 in the capacitance sensor 1. FIG. 9 is a plan view showing a process for fabricating the second dielectric layer 40 of the second sensor 12 in the capacitance sensor 1. FIG. 10 is a plan view showing a process for fabricating the second voltage application layer 42 of the second sensor 12 in the capacitance sensor 1.

[0036] The capacitance sensor 1 can be manufactured, for example, by the following steps (1) to (7). The capacitance-type sensor 1 can be manufactured by carrying out, from bottom to top, step (1) of preparing the lower insulating layer 23 shown in FIG. 5 ; step (2) of applying an elastomer composition to the lower insulating layer 23 to prepare the first voltage application layer 22 of the first sensor 11 shown in FIG. 6 ; step (3) of applying the elastomer composition to the first voltage application layer 22 to prepare the first dielectric layer 20 shown in FIG. 7 ; step (4) of applying the elastomer composition to the first dielectric layer 20 and the lower insulating layer 23 to prepare the ground layer 51 shown in FIG. 8 ; step (5) of preparing the second dielectric layer 40 of the second sensor 12 on the ground layer 51 shown in FIG. 9 ; step (6) of preparing the second voltage application layer 42 on the second dielectric layer 40 shown in FIG. 10 ; and step (7) of preparing the upper insulating layer 24 on the second voltage application layer 42 and the ground layer 51 shown in FIG. 11 . In the above steps, for example, the first dielectric layer 20, the second dielectric layer 40, the first voltage application layer 22, and the second voltage application layer 42 produced in steps (2), (3), (5), and (6) have different laminate structures for the first sensor 11 and the second sensor 12. Therefore, the layers can be produced after masking areas where no layer is to be formed according to the shape of each sensor. Each layer can be produced by an appropriate method, such as spray coating screen printing or ink jet printing.

[0037] 5, in step (1) of fabricating the lower insulating layer 23 of the capacitance sensor 1, the lower insulating layer 23 has the same or substantially the same planar shape as the capacitance sensor 1 shown in Fig. 1. The lower insulating layer 23 has a first lower insulating portion 231 located below the first voltage application layer 22 in the first sensor 11, and a second lower insulating portion 232 located below the ground layer 51 in the second sensor 12.

[0038] 6, in the step (2) of forming the capacitance sensor 1, after the lower insulating layer 23 is formed, the first voltage application layer 22 constituting the first sensor 11 is formed on the first lower insulating portion 231. The first voltage application layer 22 has the same or substantially the same planar shape as the first sensor 11 of the capacitance sensor 1 shown in FIG.

[0039] 7, in the step (3) of forming the capacitance sensor 1, after the first voltage application layer 22 is formed, the first dielectric layer 20 constituting the first sensor 11 is formed on the first voltage application layer 22. The first dielectric layer 20 has a shape that is the same as or approximately the same as the planar shape of the first sensor 11 of the capacitance sensor 1 shown in FIG.

[0040] 8 , in step (4) of forming the capacitance sensor 1, after the first dielectric layer 20 is formed, a ground layer 51 is formed on the first dielectric layer 20 and the second lower insulating portion 232. The ground layer 51 has the same or substantially the same shape as the planar shape of the capacitance sensor 1 shown in FIG. 1. The ground layer 51 has a first ground portion 511 located below the upper insulating layer 24 in the first sensor 11, and a second ground portion 512 located above the second dielectric layer 40 in the second sensor 12.

[0041] 9, in step (5) of forming the capacitance sensor 1, after the ground layer 51 is formed, the second dielectric layer 40 constituting the second sensor 12 is formed on the second ground portion 512. The second dielectric layer 40 has the same or substantially the same planar shape as the second sensor 12 of the capacitance sensor 1 shown in FIG.

[0042] 10 , in the step (6) of forming the capacitance sensor 1, after the second dielectric layer 40 is formed, a second voltage application layer 42 constituting the second sensor 12 is formed on the second dielectric layer 40. The second voltage application layer 42 has the same or substantially the same planar shape as the second sensor 12 of the capacitance sensor 1 shown in FIG.

[0043] 11 is a plan view showing a step of fabricating the upper insulating layer 24 in the capacitance sensor 1. As shown in FIG. 11 , in step (7) of forming the capacitance sensor 1, after fabricating the second voltage application layer 42, the upper insulating layer 24 is formed on the first ground portion 511 and the second voltage application layer 42. The upper insulating layer 24 has the same or substantially the same planar shape as the capacitance sensor 1 shown in FIG. 1. The upper insulating layer 24 has a first upper insulating portion 241 located above the first ground portion 511 in the first sensor 11 and a second upper insulating portion 242 located above the second voltage application layer 42 in the second sensor 12.

[0044] [Operation of Capacitive Sensor] Next, the operation of the capacitive sensor 1 having the above-described configuration will be described.

[0045] Fig. 12 is a schematic diagram showing an example of a capacitance measurement circuit 8 that uses the capacitance sensor 1. As shown in Fig. 12, the capacitance measurement circuit 8 is composed of the capacitance sensor 1 and a control IC (Integrated Circuit) 9.

[0046] In addition to the configuration described above, the capacitance sensor 1 includes a negative electrode portion 216 extending from the ground layer 51, a positive electrode portion 226 extending from the first voltage application layer 22 of the first sensor 11, and a positive electrode portion 227 extending from the second voltage application layer 42 of the second sensor 12. Note that the negative electrode portion 216 and the positive electrode portions 226, 227 are not limited to the example formed by extending from the capacitance sensor 1 as shown in Fig. 9, and may be connected by a connector for a thin board, for example.

[0047] The control IC 9 has I / O (Input / Output) ports 4 and 6 and a ground (GND) port 5. The I / O ports 4 and 6 are electrically connected to the positive electrode portions 226 and 227. The ground port 5 is electrically connected to the negative electrode portion 216. Note that in the capacitance measurement circuit 8, a switching circuit such as a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) may be provided between the capacitance sensor 1 and the control IC 9.

[0048] FIG. 13 is a schematic diagram showing the capacitance sensor 1 attached to the object to be detected 7. As shown in FIG.

[0049] As shown in Fig. 13, the capacitance sensor 1 is attached to the surface of a detection object 7 such as a long, thin round bar in order to detect torsion occurring in the detection object 7. Specifically, the capacitance sensor 1 is attached so that the first sensor 11 and the second sensor 12 are disposed obliquely (at an angle) with respect to the longitudinal direction, which is the axial direction, of the detection object 7. The capacitance sensor 1 is charged by applying a voltage from the I / O ports 4 and 6 of the control IC 9 in the capacitance measurement circuit 8 shown in Fig. 12, and measures the torsion of the detection object 7.

[0050] 13 , the capacitance sensor 1 performs measurement by attaching the first sensor 11 and the second sensor 12 at an angle to the axial direction of the object to be detected 7. In the capacitance sensor 1, the first sensor 11 and the second sensor 12 are integrally provided so as to intersect and overlap in different directions in an overlapping region 13. Therefore, the capacitance sensor 1 allows the first sensor 11 and the second sensor 12 to be attached at an angle to the axial direction of the object to be detected 7, thereby enabling highly accurate detection of torsion.

[0051] In the capacitance sensor 1, the capacitance values ​​of the first sensor 11 and the second sensor 12 change depending on whether the torsion is in the clockwise direction R or the counterclockwise direction L. Therefore, when detecting torsion occurring in the detection object 7, the capacitance sensor 1 can identify the direction of torsion (clockwise R or counterclockwise L relative to the rotation direction of the detection object 7) by comparing the capacitance value of the first sensor 11 with the capacitance value of the second sensor 12.

[0052] As described above, in the capacitance sensor 1, the first sensor 11 and the second sensor 12 overlap in a partial overlap region 13 in the planar direction. The first sensor 11 is composed of a ground layer 51, a first dielectric layer 20 sandwiched between the ground layer 51, and a first voltage application layer 22 stacked on the first dielectric layer 20. The second sensor 12 is composed of the ground layer 51, a second dielectric layer 40 sandwiched between the ground layer 51 on the surface opposite to the surface facing the first dielectric layer 20, and a second voltage application layer 42 stacked on the second dielectric layer 40. By forming the first sensor 11 and the second sensor 12 to share the ground layer 51 in this manner in the overlap region 13, the capacitance sensor 1 can prevent sensor components (sensor elements) from overlapping each other when the detection object 7 has a high ratio of height to diameter, such as a round bar, thereby reducing the thickness of the sensor elements and reducing wear and deterioration due to external forces.

[0053] Furthermore, according to the capacitance sensor 1, as described above, the first sensor 11 and the second sensor 12 share the ground layer 51 in the overlapping region 13, simplifying the stacked structure, thereby improving processability or improving attachment to the object to be detected 7 by making the sensor element thinner.

[0054] In the capacitance sensor 1, the first sensor 11 and the second sensor 12 are each rectangular with a long side and a short side in the planar direction. The first sensor 11 and the second sensor 12 intersect at an overlapping region 13. With this configuration, when the capacitance sensor 1 is attached to a detection object 7 such as a round bar as shown in FIG. 13 , it is possible to detect torsion at different positions in the longitudinal direction of the detection object 7, thereby achieving more precise detection of torsion.

[0055] In the capacitance sensor 1, the overlapping region 13 where the first sensor 11 and the second sensor 12 intersect is provided in the center in the longitudinal direction. With this configuration, the capacitance sensor 1 can detect torsion evenly regardless of the direction of torsion relative to the rotation direction of the detection object 7.

[0056] In the capacitance-type sensor 1, the first sensor 11 is formed by stacking, from bottom to top, a first voltage application layer 22, a first dielectric layer 20, and a ground layer 51, while the second sensor 12 is formed by stacking, from bottom to top, a ground layer 51 shared with the first sensor 11, a second dielectric layer 40, and a second voltage application layer 42. The capacitance-type sensor 1 also includes a lower insulating layer 23 and an upper insulating layer 24. The lower insulating layer 23 and the upper insulating layer 24 cover, in the first sensor 11, a ground layer surface 513 that is the surface of the ground layer 51 opposite to the surface facing the first dielectric layer 20, and a voltage application layer back surface 224 that is the surface of the first voltage application layer 22 opposite to the surface facing the first dielectric layer 20. In the second sensor 12, the lower insulating layer 23 and the upper insulating layer 24 cover the ground layer back surface 514, which is the surface of the ground layer 51 opposite to the surface facing the second dielectric layer 40, and the voltage application layer surface 423, which is the surface of the second voltage application layer 42 opposite to the surface facing the second dielectric layer 40.

[0057] Fig. 14 is a plan view schematically showing the configuration of a comparative capacitance sensor 100. Fig. 15 is a cross-sectional view of the capacitance sensor 100 taken along A1-A1. Fig. 16 is a cross-sectional view of the capacitance sensor 100 taken along B1-B1.

[0058] 14 to 16 has a planar shape similar to that of the capacitance sensor 1 described above, but differs from the capacitance sensor 1 in that the first sensor 111 and the second sensor 112 each have a ground layer, i.e., a first ground layer 21 and a second ground layer 41, as shown in FIGS. 15 and 16 . The capacitance sensor 100 also differs from the capacitance sensor 1 in that an upper insulating layer 24 is laminated above the first ground layer 21 of the first sensor 11, and a second voltage application layer 42 of the second sensor 12 is laminated above the upper insulating layer 24. The capacitance sensor 100 also differs from the capacitance sensor 1 in that a second upper insulating layer 44 is provided above the second ground layer 41 of the second sensor 112, separate from the upper insulating layer 24 of the first sensor 111.

[0059] 2 and 3, the capacitance sensor 1 described above is made up of seven layers, from the bottom lower insulating layer 23 to the top upper insulating layer 24. On the other hand, as shown in Figures 15 and 16, the capacitance sensor 100 of the comparative example is made up of nine layers, from the bottom lower insulating layer 23 of the first sensor 111 to the top second upper insulating layer 44 of the second sensor 112.

[0060] As described above, the capacitance sensor 1 shares the ground layer 51, which is one of the electrode layers, between the first sensor 11 and the second sensor 12. This eliminates the need for the first and second sensors 11 and 12 to have the first and second ground layers 21 and 41, respectively, as in the capacitance sensor 100 of the comparative example. Furthermore, the capacitance sensor 1 eliminates the need for an insulating layer (second upper insulating layer 44) between the first and second sensors 11 and 12, as in the capacitance sensor 100 of the comparative example. Therefore, as shown in steps (1) to (7) above, the capacitance sensor 1 can simplify the manufacturing process and stacking structure of the capacitance sensor 1 compared to the capacitance sensor 100 of the comparative example. In other words, the capacitance sensor 1 can be made easier to process and thinner in the stacking direction. Furthermore, the capacitance sensor 1 can be made thinner in the stacking direction, thereby improving the ease of attachment to the detection object 7, as described above.

[0061] Therefore, the capacitance type sensor 1 can simplify the structure in which a plurality of sensor elements are formed on the same sheet.

[0062] In addition, those skilled in the art can appropriately modify the present invention in accordance with conventionally known knowledge. As long as such modifications still comprise the structure of the present invention, they are of course included in the scope of the present invention.

[0063] For example, in the capacitance sensor 1 described above, an example has been described in which the lower insulating layer 23 and the upper insulating layer 24 cover only the top and bottom surfaces of the first dielectric layer 20, the ground layer 51, and the first voltage application layer 22, but the lower insulating layer 23 and the upper insulating layer 24 may cover the top, bottom, and side surfaces of the first dielectric layer 20, the ground layer 51, and the first voltage application layer 22.

[0064] For example, the capacitance sensor 1 described above is not limited to the round bar-shaped detection object 7 shown in FIG. 13, and can be used to detect the twist of detection objects of various shapes.

[0065] 1,100...capacitive sensor, 3...capacitor, 4, 6...I / O (Input / Output) port, 5...ground port, 7...detected object, 8...capacitance measurement circuit, 11,111...first sensor, 12,112...second sensor, 13...overlapping area, 14...long side, 15...short side, 20...first dielectric layer (dielectric layer), 21...first ground layer, 22...first voltage application layer (voltage application layer), 23...lower insulating layer, 24...upper insulating layer, 30...dielectric, 31...negative side electrode, 32...positive side electrode, 40...second dielectric layer (dielectric layer), 41...second ground layer, 42...second voltage application application layer (voltage application layer), 44...second upper insulating layer, 51...ground layer, 203, 403...surface of dielectric layer, 204, 404...rear surface of dielectric layer, 216...negative electrode portion, 223, 423...surface of voltage application layer, 224, 424...rear surface of voltage application layer, 226...positive electrode portion, 227...positive electrode portion, 231...first lower insulating portion, 232...second lower insulating portion, 233...surface of lower insulating layer, 241...first upper insulating portion, 242...second upper insulating portion, 244...rear surface of upper insulating layer, 511...first ground portion, 512...second ground portion, 513...surface of ground layer, 514...rear surface of ground layer

Claims

1. A capacitance type sensor comprising a first sensor and a second sensor, wherein the first sensor and the second sensor each have at least a ground layer, a dielectric layer, and a voltage application layer laminated therein, overlapping in a portion of a surface direction and having a common ground layer.

2. The capacitance type sensor according to claim 1, wherein the first sensor is formed by stacking the voltage application layer, the dielectric layer, and the ground layer in that order from the bottom in the stacking direction, and the second sensor is formed by stacking the ground layer, the dielectric layer, and the voltage application layer in that order from the bottom in the stacking direction.

3. The capacitance type sensor according to claim 1 or 2, further comprising an insulating layer, the insulating layer comprising: a lower insulating layer laminated below the voltage application layer in the first sensor; and an upper insulating layer laminated above the voltage application layer in the second sensor.

4. The capacitance type sensor according to claim 1 or 2, wherein the first sensor and the second sensor are each rectangular in shape having a longer side and a shorter side in the planar direction and intersect in the region.

5. The capacitance type sensor according to claim 4, wherein the first sensor and the second sensor intersect at a center portion in the longitudinal direction.

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