pressure sensor

Abstract

To provide a pressure sensor capable of improving detection sensitivity. [Solution] The pressure sensor 1 comprises an ionic material layer 40, a first electrode 10 provided on a first surface 41 of the ionic material layer 40, an elastic body 30 having conductivity and positioned opposite to a second surface 42 of the ionic material layer 40, and a second electrode 20 connected to the elastic body 30. There are multiple first electrodes 10 and multiple elastic bodies 30 so that multiple composite capacitors can be formed by connecting multiple composite capacitors in parallel to the first electrode 10. Each of the multiple composite capacitors includes a first capacitor formed between the first electrode 10 and the ionic material layer 40, and a second capacitor formed between the ionic material layer 40 and the elastic body 30. The ionic material layer 40 is common to the multiple composite capacitors. The capacitance of the second capacitor changes as the contact area of ​​the contact portion between the elastic body 30 and the ionic material layer 40 changes in response to the pressure applied to the elastic body 30.

Description

Technical Field

[0001] The present disclosure relates to a pressure sensor. More specifically, the present disclosure relates to a pressure sensor for detecting a reaction force generated when contacting an object.

Background Art

[0002] Patent Document 1 discloses a flexible capacitor array used for detecting pressure. This flexible capacitor array is configured by arranging a plurality of capacitor cells in an array.

[0003] Each of the plurality of capacitor cells includes a first flexible electrode and a second flexible electrode. A dielectric layer, which is an ion gel thin film, and a spacer are disposed between the first flexible electrode and the second flexible electrode. The second flexible electrode is in contact with the first surface of the dielectric layer. The first flexible electrode faces the second surface of the dielectric layer through a spacer layer. Each individual capacitor cell includes a first electric double layer capacitor, which is a variable capacitor structure formed between the first flexible electrode and the dielectric layer, and a second electric double layer capacitor formed between the second flexible electrode and the dielectric layer.

[0004] Here, when pressure is applied to the first flexible electrode, the distance between the first flexible electrode and the dielectric layer decreases, and the capacitance of the first electric double layer capacitor changes. As a result, the capacitance between the first flexible electrode and the second flexible electrode changes, so the pressure applied to the first flexible electrode can be detected from the change in the capacitance between the first flexible electrode and the second flexible electrode.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] The purpose of this disclosure is to provide a pressure sensor capable of improving detection sensitivity. [Means for solving the problem]

[0007] A pressure sensor according to one aspect of the present disclosure comprises an ionic material layer, a first electrode, an elastic body, and a second electrode. The first electrode is provided on a first surface in the thickness direction of the ionic material layer. The elastic body is conductive and is positioned opposite a second surface in the thickness direction of the ionic material layer. The second electrode is connected to the elastic body. There are multiple first electrodes and elastic bodies so that a plurality of composite capacitors can be formed by connecting them in parallel to the first electrode. Each of the plurality of composite capacitors includes a first capacitor formed between the first electrode and the ionic material layer, and a second capacitor formed between the ionic material layer and the elastic body. The ionic material layer is common to the plurality of composite capacitors. The capacitance of the second capacitor changes as the contact area of ​​the contact portion between the elastic body and the ionic material layer changes in response to the pressure applied to the elastic body. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide a pressure sensor capable of improving detection sensitivity. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a cross-sectional view of a pressure sensor according to Embodiment 1 of the present disclosure. [Figure 2] Figure 2 is a cross-sectional view of the same pressure sensor. [Figure 3] Figure 3 is a plan view of the same pressure sensor. [Figure 4] Figure 4 is a schematic circuit diagram of the pressure sensor described above. [Figure 5]FIG. 5 is a plan view of the pressure sensor according to Modification 1 of Embodiment 1. [Figure 6] FIG. 6 is a cross-sectional view of the pressure sensor according to Embodiment 2 of the present disclosure. [Figure 7] FIG. 7 is a plan view of the pressure sensor described above. [Figure 8] FIG. 8 is a schematic circuit diagram of the pressure sensor described above. [Figure 9] FIG. 9 is a waveform diagram of each part of the pressure sensor described above. [Figure 10] FIG. 10 is a schematic circuit diagram of the pressure sensor according to Modification 1 of Embodiment 2. [Figure 11] FIG. 11 is a cross-sectional view of the pressure sensor according to Modification 2 of Embodiment 2. [Figure 12] FIG. 12 is a plan view of the pressure sensor described above. [Figure 13] FIG. 13 is a bottom view of the pressure sensor described above. [Figure 14] FIG. 14 is a cross-sectional view of the pressure sensor according to Embodiment 3 of the present disclosure. [Figure 15] FIG. 15 is a schematic equivalent circuit diagram of the pressure sensor described above. [Figure 16] FIG. 16 is a schematic circuit diagram of the pressure sensor described above. [Figure 17] FIG. 17 is a waveform diagram of each part of the pressure sensor described above. [Figure 18] FIG. 18 is a schematic circuit diagram of the pressure sensor according to Modification 1 of Embodiment 3. [Figure 19] FIG. 19 is a cross-sectional view of the pressure sensor according to Embodiment 4 of the present disclosure. [Figure 20] FIG. 20 is a plan view of the pressure sensor described above. [[ID=4​​​​​​​​​​ Hereinafter, the pressure sensor according to the embodiment will be described in detail with reference to the drawings. However, each of the drawings described in the following embodiments is a schematic diagram, and the dimensional ratios such as the sizes of each component do not necessarily reflect the actual dimensional ratios. Further, the configurations described in the following embodiments are merely examples of the present disclosure. The present disclosure is not limited to the following embodiments, and various modifications can be made according to the design and the like as long as the effects of the present disclosure can be achieved.

[0011] (1) Embodiment 1 (1-1) Overview As shown in FIGS. 1 and 2, the pressure sensor 1 of the present embodiment includes an ionic material layer 40, a first electrode 10, an elastic body 30, and a second electrode 20. In the following description, the pressure sensor 1 of Embodiment 1 may also be referred to as the pressure sensor 1A.

[0012] The first electrode 10 is provided on the first surface 41 in the thickness direction of the ionic material layer 40.

[0013] The elastic body 30 has conductivity and is disposed opposite to the second surface 42 in the thickness direction of the ionic material layer 40.

[0014] The second electrode 20 is connected to the elastic body 30.

[0015] At least one of the first electrode 10 and the elastic body 30 is plural so that a plurality of combined capacitors Cn (C1 to C4) connected in parallel to the first electrode 10 can be formed (see FIG. 4).

[0016] Each of the plurality of combined capacitors Cn (C1 to C4) includes a first capacitor C1n (C11 to C14) and a second capacitor C2n (C21 to C24) (see FIG. 4). The first capacitor C1n (C11 to C14) is formed between the first electrode 10 and the ionic material layer 40. The second capacitor C2n (C21 to C24) is formed between the ionic material layer 40 and the elastic body 30.

[0017] The ionic material layer 40 is common to multiple synthetic capacitors Cn(C1~C4).

[0018] The contact area between the elastic body 30 and the ionic material layer 40 changes in response to the pressure applied to the elastic body 30, thereby changing the capacitance of the second capacitor C2n (C21~C24).

[0019] Here, an ionic liquid is a substance that exists as an ion in a liquid state without a solvent at room temperature, and the ionic material layer 40 is a substance in which ionic liquid molecules can move within a solid, such as by impregnating an ionic liquid into a gel polymer. The ionic material layer 40 is, for example, a sheet-like ionic gel with an ionic liquid as the solvent. The ionic material layer 40 is, for example, made by impregnating the ionic liquid [EMI][TFSI](1-Ethyl-3-methylimidazolium bis-(trifluoromethylsulfonyl)imide) into PDMA (polydimethylacrylamide). The ionic material layer 40 may also be made by impregnating the ionic liquid [EMIm][BF4](1-Ethyl-3-methylimidazolium,BF4) into PVDF-HFP (poly(vinylidene fluoride-hexafluoropropylene)), and the materials of the ionic liquid and gel polymer can be changed as appropriate.

[0020] Furthermore, the conductive elastic body 30 is, for example, made by introducing conductive carbon particles into silicone rubber. Alternatively, it may be made by introducing conductive carbon particles into EPDM rubber (ethylene propylene diene rubber), and the material of the elastic body 30 can be changed as appropriate. It is preferable that the elastic modulus of the elastic body 30 be set to a value smaller than the elastic modulus of the ionic material layer 40. It is also preferable that the thickness of the elastic body 30 is greater than the thickness of the ionic material layer 40. This configuration ensures that when the elastic body 30 is pressed against the ionic material layer 40, the elastic body 30 undergoes elastic deformation, increasing the contact area between the ionic material layer 40 and the elastic body 30.

[0021] For example, when an object comes into contact with the flexible substrate 50 provided above the first electrode 10, a downward force is applied to the elastic body 30 due to the reaction force. As the contact area between the elastic body 30 and the ionic material layer 40 increases due to the force applied to the elastic body 30, the capacitance of the second capacitor C2n formed between the elastic body 30 and the ionic material layer 40 changes. Here, the capacitance of the second capacitor C2n can be measured from the voltage value when a charging current is passed through a composite capacitor Cn which includes the second capacitor C2n and the first capacitor C1n connected in series with the second capacitor C2n. In this embodiment, since the ionic material layer 40 is common to multiple composite capacitors Cn, for example, when measuring the capacitance of a second capacitor C21, it is possible to measure the capacitance of the second capacitor C21 from the voltage value obtained when a charging current is passed through the first capacitor C11 connected in series with the second capacitor C21, the first capacitor C12 adjacent to the first capacitor C11, and the second capacitor C21 being measured. In this case, since the first capacitors C11 and C12 are connected in parallel, the combined capacitance of the first capacitors C11 and C12 is smaller than that of the first capacitor C11 alone. Therefore, when determining the capacitance of the second capacitor C21 from the combined capacitance of the first capacitors C11 and C12 and the second capacitor C21, the capacitance of the second capacitor C21 can be measured with greater accuracy and detection sensitivity can be improved compared to when determining the capacitance of the second capacitor C21 from the combined capacitance of the first capacitor C11 and the second capacitor C21. Furthermore, since the change in capacitance of the second capacitor C21 is proportional to the magnitude of the force applied to the elastic body 30, the pressure sensor 1A can be used to detect the position and strength of the applied force. In this embodiment, the pressure sensor 1A is used in robot hands and the like to detect the reaction force generated when an object comes into contact with the contact surface, as well as the contact position of the object. However, the applications of the pressure sensor 1A are not limited to the above applications and can be applied to a variety of other applications.

[0022] (1-2) Composition The configuration of the pressure sensor 1A of Embodiment 1 will be described in detail below with reference to Figures 1 to 4. In the following description, the X-axis direction in Figures 1 to 3 is defined as the left-right direction, the Y-axis direction as the front-back direction (depth direction), and the Z-axis direction (normal direction to the first surface 41 and the second surface 42 of the ionic material layer 40) as the up-down direction. Furthermore, the positive direction in the X-axis direction is defined as the right side, the positive direction in the Y-axis direction as the front side, and the positive direction in the Z-axis direction as the up side. However, these directions are merely examples and are not intended to limit the direction in which the pressure sensor 1A can be used. Also, the arrows indicating each direction in the drawings are for illustrative purposes only and do not represent actual objects.

[0023] As described above, the pressure sensor 1A comprises an ionic material layer 40, a first electrode 10, an elastic body 30, and a second electrode 20. The pressure sensor 1A further comprises a sheet-like flexible substrate 50 on which the first electrode 10 is provided on one surface.

[0024] The flexible substrate 50 is a sheet-like substrate made from, for example, a polyimide or polyester film as a base material. The first electrode 10 is provided over substantially the entire surface of one side of the flexible substrate 50. An ionic material layer 40 is provided over the entire surface of the first electrode 10 opposite to the flexible substrate 50. For example, when a part of the surface of the flexible substrate 50 (the surface opposite to the first electrode 10) is pressed, a force is applied to the elastic body 30 via the first electrode 10 and the ionic material layer 40, causing the elastic body 30 directly below and around the point of force application to elastically deform, increasing the contact area with the ionic material layer 40.

[0025] In this embodiment, as shown in Figures 1 and 2, the elastic body 30 includes a plurality of individual elastic bodies 3n, each corresponding to a plurality of composite capacitors Cn. The plurality of individual elastic bodies 3n are separated from each other, and each of the plurality of individual elastic bodies 3n is provided with an individual second electrode 20. Each individual elastic body 3n is provided with two mountain-shaped protrusions 301 aligned along the second direction on the surface facing the ionic material layer 40. In this way, since the elastic body 30 includes a plurality of individual elastic bodies 3n, a plurality of composite capacitors Cn are formed between the plurality of individual elastic bodies 3n and the first electrode 10. Here, the individual elastic bodies 3n corresponding to each of the composite capacitors C1 to C4 may also be referred to as individual elastic bodies 31 to 34. Also, the second electrodes 20 provided on the individual elastic bodies 31 to 34 may also be referred to as second electrodes 21 to 24. The first electrode 10 is provided with terminal X1, and the second electrodes 21 to 24 are provided with terminals Y1 to Y4, respectively. Terminals X1, Y1~Y4 may be components (terminals) for connecting wires or wiring on a printed circuit board, but they may also be, for example, leads of electronic components or parts of conductive material formed as wiring on a printed circuit board.

[0026] Figure 3 is a plan view of the pressure sensor 1A as seen from above. In this embodiment, multiple individual elastic bodies 3n are arranged at equal intervals along the X-axis. In other words, the multiple individual elastic bodies 3n are arranged one-dimensionally with spacing along one direction.

[0027] Figures 1 and 2 are ZX cross-sectional views of a portion of the pressure sensor 1A. Figure 1 is a ZX cross-sectional view of the pressure sensor 1A when no external force is applied. Figure 2 is a ZX cross-sectional view of the flexible substrate 50 when a force is applied to a portion of its upper surface. In Figure 2, not only the elastic body 30 directly below the force application point is elastically deformed, but also the elastic body 30 adjacent to the elastic body 30 directly below it is elastically deformed. However, the configuration may be such that only the elastic body 30 directly below the force application point is elastically deformed.

[0028] The pressure sensor 1A of this embodiment further includes a detection circuit 70 that detects the capacitance of the second capacitor C2n contained in each of the multiple composite capacitors Cn. The pressure sensor 1A also further includes a switch SW1, a selector switch SW2, a DC power supply E1, a capacitor Cx, and a buffer amplifier B1.

[0029] In this embodiment, since the elastic body 30 has a plurality of individual elastic bodies 3n that are separated from each other, a composite capacitor Cn (C1 to C4) is formed between each of the plurality of individual elastic bodies 3n (31 to 34) and the first electrode 10.

[0030] Figure 4 shows the equivalent circuit of the composite capacitor Cn formed between the first electrode 10 and the second electrode 20. Here, the composite capacitor Cn (C1~C4) includes the first capacitor C1n (C11~C14) and the second capacitor C2n (C21~C24). The first capacitor C1n (C11~C14) is an electric double-layer capacitor formed between the portion of the first electrode 10 facing the individual elastic bodies 3n (31~34) and the ionic material layer 40. The second capacitor C2n is an electric double-layer capacitor formed between the individual elastic bodies 3n (31~34) and the ionic material layer 40. The first capacitor C1n and the second capacitor C2n are connected in series via a resistor r1 representing the resistance component in the thickness direction of the ionic material layer 40. Each individual elastic body 3n is provided with two protrusions 301 on the surface facing the ionic material layer 40, and the tips of the two protrusions 301 are in contact with the ionic material layer 40. Therefore, the capacitance of the second capacitor C2n is equal to the capacitance of the composite capacitor formed by connecting two electric double-layer capacitors, each formed between the two protrusions 301 and the ionic material layer 40, in parallel.

[0031] Furthermore, if the resistance present between the contact portion with the individual elastic body 31 and the contact portion with the individual elastic body 32 in the ionic material layer 40 is denoted as resistance R12, then the first capacitor C11 and the first capacitor C12 are connected via resistance R12. If the resistance present between the contact portion with the individual elastic body 32 and the contact portion with the individual elastic body 33 in the ionic material layer 40 is denoted as resistance R23, then the first capacitor C12 and the first capacitor C13 are connected via resistance R23. If the resistance present between the contact portion with the individual elastic body 33 and the contact portion with the individual elastic body 34 in the ionic material layer 40 is denoted as resistance R34, then the first capacitor C13 and the first capacitor C14 are connected via resistance R34.

[0032] Furthermore, in the ionic material layer 40, the distance between the contact portion with the individual elastic body 31 and the contact portion with the individual elastic body 32 is several times to more than ten times the thickness of the ionic material layer 40, so resistor R12 has a resistance value several times to more than ten times that of resistors r1 and r2. Similarly, resistor R23 has a resistance value several times to more than ten times that of resistors r2 and r3, and resistor R34 has a resistance value several times to more than ten times that of resistors r3 and r4.

[0033] Switch SW1 is connected between a DC power supply E1, which outputs a DC voltage of a predetermined value, and a capacitor Cx. Switch SW1 is switched on / off by a detection circuit 70.

[0034] The first terminal of capacitor Cx is connected to the circuit's common voltage (circuit ground), and the second terminal of capacitor Cx is connected to switch SW1.

[0035] The selector switch SW2 has a common terminal connected to the connection point between switch SW1 and capacitor Cx, and multiple switching terminals connected to terminals Y1 to Y4, respectively. The selector switch SW2 connects one of the multiple switching terminals to the common terminal according to the control signal from the detection circuit 70.

[0036] Buffer amplifier B1 outputs the voltage Vm at the connection point between selector switch SW2 and capacitor Cx to detection circuit 70.

[0037] The detection circuit 70 determines the capacitance of the second capacitor C2n to be measured based on the voltage value Vm input from the buffer amplifier B1, and detects the magnitude of the force applied to the elastic body 30 based on the capacitance of the second capacitor C2n.

[0038] The detection circuit 70 may include a computer system. The computer system mainly consists of a processor and memory as hardware. The functions of the detection circuit 70 in this disclosure are realized by the processor executing a program recorded in the memory of the computer system.

[0039] (1-3) Operation Description The following describes how the detection circuit 70 measures the capacitance of the second capacitor C2n contained in each of the multiple composite capacitors Cn, and detects the force applied to the elastic body 30 based on the capacitance of the second capacitor C2n.

[0040] More specifically, the detection circuit 70 controls the selector switch SW2 to ensure that all switching terminals are not connected to the common terminal. Then, the detection circuit 70 keeps switch SW1 ON for a predetermined time to charge capacitor Cx to the output voltage V1 of the DC power supply E1.

[0041] Next, the detection circuit 70 does not supply charging current to one or more of the multiple composite capacitors Cn other than the composite capacitor Cn being measured, and supplies charging current only to the composite capacitor Cn being measured. Here, the state in which charging current does not flow to one or more composite capacitors Cn other than the composite capacitor Cn being measured means that one or more composite capacitors Cn other than the composite capacitor Cn being measured are in an open state. The detection circuit 70 controls the selector switch SW2 to connect the composite capacitor Cn being measured to the common terminal, thereby connecting the composite capacitor Cn being measured to capacitor Cx. At this time, one or more composite capacitors Cn other than the composite capacitor Cn being measured are in an open state. Then, charging current flows from capacitor Cx to the composite capacitor Cn being measured, and the voltage Vm across the ends of capacitor Cx gradually decreases.

[0042] The detection circuit 70 measures the voltage between the second electrode 20 and the first electrode 10 (i.e., the voltage across the synthetic capacitor Cn being measured) at a measurement timing after a charging current has been applied for a charging time longer than the time constant of the circuit (e.g., an RC circuit) containing the synthetic capacitor Cn being measured and the ionic material layer 40. Based on the measured voltage, the detection circuit 70 then detects the capacitance of the second capacitor C2n included in the synthetic capacitor Cn being measured.

[0043] If the detection circuit 70 measures, for example, the composite capacitor C1 between the first electrode 10 and the second electrode 21, the time constant of the RC circuit composed of the capacitance C_X1Y1 of the composite capacitor C1 and the resistance r1 of the ionic material layer 40 is (r1·C_X1Y1). Therefore, the detection circuit 70 measures the voltage Vm at a measurement timing after supplying a charging current to the composite capacitor C1 for a charging time longer than the time constant (r1·C_X1Y1), and calculates the capacitance of the second capacitor C21 included in the composite capacitor C1 based on the measured voltage value.

[0044] The detection circuit 70 switches the composite capacitor Cn to be measured in the order of, for example, composite capacitors C1, C2, C3, and C4, and sequentially measures the second capacitors C21 to C24 included in composite capacitors C1 to C4. Here, when the elastic body 30 deforms due to the force applied to the flexible substrate 50, the contact area of ​​the contact point between the elastic body 30 and the ionic material layer 40 changes, and the capacitance of the second capacitor C2n formed between the elastic body 30 and the ionic material layer 40 changes. The detection circuit 70 has pre-set relational formulas that represent the correspondence between the capacitance of the second capacitor C2n and the force applied to the flexible substrate 50. Therefore, the detection circuit 70 can detect the position and magnitude of the force applied to the flexible substrate 50 based on the measurement result of the capacitance of the second capacitor C2n and the relational formula that represents the correspondence between the capacitance of the second capacitor C2n and the force applied to the flexible substrate 50. In this embodiment, since the elastic body 30 includes a plurality of individual elastic bodies 3n that are separated from each other, the resolution of the force application position by the detection circuit 70 can be set to the size of each individual elastic body 3n.

[0045] (1-4) Modifications of Embodiment 1 Embodiment 1 described above is merely one of many embodiments of this disclosure. Embodiment 1 can be modified in various ways depending on the design, etc., as long as it achieves the objectives of this disclosure.

[0046] The following lists modifications of Embodiment 1. The modifications described below can be combined and applied as appropriate. Note that the pressure sensor 1A of Embodiment 1 may also be referred to as Basic Configuration 1 below.

[0047] (1-4-1) Torture 1 Figure 5 is a plan view of a pressure sensor 1A according to Modification 1 of Embodiment 1. The pressure sensor 1A of Modification 1 differs from the basic configuration 1 in that a plurality of individual elastic bodies 3n are arranged two-dimensionally. Except for the arrangement of the plurality of individual elastic bodies 3n, the pressure sensor 1A of Modification 1 has the same configuration as the pressure sensor 1A of the basic configuration 1, so the same reference numerals are used for the common components and their descriptions are omitted.

[0048] In the pressure sensor 1A of Modified Example 1, for example, multiple individual elastic bodies 3n are arranged in a matrix such that rows of multiple (e.g., four) individual elastic bodies 3n are arranged along the X direction, and multiple (e.g., two) rows are arranged at equal intervals along the Y axis. In other words, the multiple individual elastic bodies 3n are arranged two-dimensionally in a plane (the XY plane in this modified example) parallel to the second surface 42 of the ionic material layer 40. Since the multiple individual elastic bodies 3n are arranged two-dimensionally, the position and strength of the force applied can be detected in a planar detection area. In other words, the detection circuit 70 can detect the force application position two-dimensionally within the two-dimensional region where the multiple individual elastic bodies 3n are arranged. Therefore, in Modified Example 1, a highly sensitive pressure sensor 1A with planar resolution can be realized.

[0049] (1-4-2) Other variations The structure of the pressure sensor 1A described in Basic Configuration 1 is an example, and the shape and number of the first electrodes 10 can be changed as appropriate. Similarly, the shape and number of the elastic bodies 30 can be changed as appropriate, as can the shape and number of the second electrodes 20 connected to the elastic bodies 30.

[0050] Basic configuration 1 was explained using the example of an object contacting the surface of the flexible substrate 50, but a configuration in which a force is applied to the elastic body 30 by an object contacting the flexible substrate on which the second electrode 20 is mounted is also acceptable.

[0051] In basic configuration 1, the second electrode 20 is provided over the entire lower surface of the elastic body 30, but the second electrode 20 may be provided only on a part of the lower surface of the elastic body 30.

[0052] (2) Embodiment 2 The pressure sensor 1 according to Embodiment 2 will be described in detail below with reference to Figures 6 to 9. In the following, the pressure sensor 1 of Embodiment 2 may also be referred to as pressure sensor 1B. In the pressure sensor 1B of Embodiment 2, components common to the pressure sensor 1A of Embodiment 1 and its modified form are denoted by the same reference numerals, and their descriptions are omitted.

[0053] (2-1) Composition The pressure sensor 1B of Embodiment 2 comprises an ionic material layer 40, a first electrode 10, an elastic body 30, a second electrode 20, and a flexible substrate 50, similar to Embodiment 1.

[0054] In the pressure sensor 1B of Embodiment 2, the first electrode 10 includes a plurality (e.g., 3) of first linear electrodes 11-13 whose longitudinal direction is parallel to the first surface 41 of the ionic material layer 40 (e.g., the Y direction).

[0055] Multiple first linear electrodes 11-13 are arranged on the first surface 41 of the ionic material layer 40, spaced apart in a second direction (e.g., the X direction) that is parallel to the first surface 41 and perpendicular to the first direction. Note that "perpendicular" is not limited to the two directions intersecting at a right angle; for example, they may intersect at an angle of 60 to 120 degrees. Terminals X1, X2, and X3 are provided on the first linear electrodes 11, 12, and 13, respectively.

[0056] Furthermore, the pressure sensor 1B of Embodiment 2 includes a plurality of elastic bodies 30. The plurality of elastic bodies 30 are arranged with spacing in the first direction so that a plurality of composite capacitors Cn are lined up along the first and second directions, respectively (see Figure 7).

[0057] Furthermore, each of the multiple elastic bodies 30 includes multiple linear elastic bodies 32n whose longitudinal direction is the second direction. Each of the multiple linear elastic bodies 32n has multiple parts that overlap with the multiple first linear electrodes 11 to 13 in the direction normal to the second surface 42, which are integrated together. When describing the multiple linear elastic bodies 32n separately, they may be referred to as linear elastic bodies 321, 322, and 323.

[0058] Each of the multiple linear elastic bodies 321, 322, and 323 is provided with a second electrode 20. When describing the second electrodes 20 provided on each of the linear elastic bodies 321, 322, and 323 separately, they may be referred to as second electrodes 210, 220, and 230. Each of the second electrodes 210, 220, and 230 is provided with terminals Y1, Y2, and Y3, respectively. Note that the multiple second electrodes 210, 220, and 230 may be mounted on the surface of a common substrate.

[0059] In the pressure sensor 1B of Embodiment 2, a plurality of first linear electrodes 11, 12, 13 and a plurality of linear elastic bodies 321, 322, 323 are arranged to intersect each other. A composite capacitor Cn is formed in the portion where the plurality of first linear electrodes 11, 12, 13 and the plurality of linear elastic bodies 321, 322, 323 overlap in the Z-axis direction. The composite capacitor Cn includes a first capacitor C1n formed between the first electrode 10 (any of the first linear electrodes 11 to 13) and the ionic material layer 40, and a second capacitor C2n formed between the ionic material layer 40 and the elastic body 30 (any of the linear elastic bodies 321, 322, 323).

[0060] Furthermore, the pressure sensor 1B is further equipped with a detection circuit 70 that detects the capacitance of the second capacitor C2n contained in each of the multiple composite capacitors Cn (see Figure 8). The pressure sensor 1B is further equipped with switches SW1 and SW3, a DC power supply E1, a capacitor Cx, and a buffer amplifier B1.

[0061] Switch SW1 is connected between a DC power supply E1, which outputs a DC voltage of a predetermined value, and a capacitor Cx. Switch SW1 is switched on / off by a detection circuit 70.

[0062] The first terminal of capacitor Cx is connected to the circuit's common voltage (circuit ground), and the second terminal of capacitor Cx is connected to switch SW1.

[0063] The first end of switch SW3 is connected to the connection point between switch SW1 and capacitor Cx, and the second end of switch SW3 is connected to one of terminals X1 to X3. The detection circuit 70 switches the connection destination of the second end of switch SW3. Figure 8 shows the state in which the second end of switch SW3 is connected to terminal X1. In this case, the second end of switch SW3 is connected to a composite capacitor C1 formed between the first linear electrode 11 connected to terminal X1 and the linear elastic bodies 321, 322, 323 connected to terminals Y1, Y2, Y3. This composite capacitor C1 includes a first capacitor C11 formed between the first linear electrode 11 and the ionic material layer 40, and second capacitors C21, C22, C23 formed between the linear elastic bodies 321, 322, 323 and the ionic material layer 40.

[0064] Here, the first capacitor C11 and the second capacitor C21 are connected via a resistor r1, which is the resistive component of the ionic material layer 40. The first capacitor C11 and the second capacitor C22 are connected via a resistor R2, which is the resistive component of the ionic material layer 40. The first capacitor C11 and the second capacitor C23 are connected via a resistor R3, which is the resistive component of the ionic material layer 40. The resistance values ​​of resistors r1, R2, and R3 are proportional to the distance between the first linear electrode 11 and the linear elastic bodies 321, 322, and 323. Since the distance between the first linear electrode 11 and the linear elastic bodies 322 and 323 is several times to more than ten times the distance between the first linear electrode 11 and the linear elastic body 321, the values ​​of resistors R2 and R3 are several times to more than ten times the value of resistor r1.

[0065] Buffer amplifier B1 outputs the voltage Vm at the connection point between switch SW1 and capacitor Cx to detection circuit 70.

[0066] The detection circuit 70 detects the capacitance of the second capacitor C2n to be measured based on the voltage value Vm input from the buffer amplifier B1. The detection circuit 70 measures the capacitance of the second capacitor C2n contained in each of the multiple composite capacitors Cn. Then, based on the measurement result of the capacitance of the second capacitor Cn2, the detection circuit 70 detects the magnitude of the force applied to the elastic body.

[0067] (2-2) Operation Description The operation of the detection circuit 70 when detecting the magnitude of the force applied to the intersection where the first linear electrode 11 and the linear elastic body 321 overlap in the Z-axis direction will be explained below with reference to Figure 9. In this case, the detection circuit 70 detects the capacitance of the second capacitor C21 formed at the intersection where the first linear electrode 11 and the linear elastic body 321 overlap in the Z-axis direction, and detects the magnitude of the force applied to the intersection based on the capacitance of the second capacitor C21.

[0068] More specifically, the detection circuit 70 controls switch SW3 to ensure that all terminals X1 to X3 are not connected to capacitor Cx. Then, the detection circuit 70 turns switch SW1 on for a predetermined time (from time t1 to time t2) to charge capacitor Cx to the output voltage V1 of the DC power supply E1.

[0069] Next, the detection circuit 70 does not supply charging current to one or more of the multiple composite capacitors Cn other than the composite capacitor Cn being measured, and supplies charging current only to the composite capacitor Cn being measured. More specifically, the detection circuit 70 connects a capacitor Cx charged to a predetermined voltage to the composite capacitor Cn being measured, thereby supplying charging current to the composite capacitor Cn being measured. Here, the state in which charging current is not supplied to one or more composite capacitors Cn other than the composite capacitor Cn being measured means that one or more composite capacitors Cn other than the composite capacitor Cn being measured are in an open state. At time t3, the detection circuit 70 connects the composite capacitor Cn being measured to capacitor Cx by connecting the second end of switch SW3 to the terminal (any of terminals X1 to X3) to which the composite capacitor Cn being measured is connected. At this time, one or more composite capacitors Cn other than the composite capacitor Cn being measured are in an open state. Then, charging current flows from capacitor Cx to the composite capacitor Cn being measured, and the voltage Vm across both ends of capacitor Cx gradually decreases.

[0070] The detection circuit 70 measures the voltage Vm between the second electrode 20 and the first electrode 10 at a measurement timing after a charging current has been applied for a charging time longer than the time constant of the circuit including the synthetic capacitor Cn and the ionic material layer 40 to be measured. Based on the measurement result of the voltage Vm, the detection circuit 70 then detects the capacitance of the second capacitor C2n included in the synthetic capacitor Cn to be measured.

[0071] For example, when the detection circuit 70 detects the magnitude of the force applied to the intersection where the first linear electrode 11 and the linear elastic body 321 overlap in the Z-axis direction, the detection circuit 70 detects the capacitance of the second capacitor C21 formed at the intersection.

[0072] If the capacitance value of the combined capacitor between the first linear electrode 11 and the linear elastic body 321 is C_X1Y1, then the time constant of the RC circuit composed of the combined capacitor between the first linear electrode 11 and the linear elastic body 321 and resistor r1 is (r1·C_X1Y1). Also, if the capacitance value of the combined capacitor between the first linear electrode 12 adjacent to the first linear electrode 11 and the linear elastic body 321 is C_X2Y1, then the time constant of the RC circuit composed of the combined capacitor between the first linear electrode 12 and the linear elastic body 321 and resistor R2 is (R2·C_X2Y1).

[0073] Therefore, the detection circuit 70 measures the voltage Vm at a measurement timing (time t4) after a charging current CT1 has been applied to the composite capacitor C1 to be measured for a charging time longer than the time constant (r1·C_X1Y1) and sufficiently shorter than the time constant (R2·C_X2Y1). By setting the measurement timing to the point after the charging time CT1, which is longer than the time constant (r1·C_X1Y1) and sufficiently shorter than the time constant (R2·C_X2Y1), the capacitance of the first capacitor can be increased, and the second capacitor C21 can be detected with higher sensitivity.

[0074] The detection circuit 70 then calculates the capacitance of the second capacitor C21 to be measured based on the voltage value Vm measured at time t4. Furthermore, based on the capacitance of the second capacitor C21, the detection circuit 70 detects the magnitude of the force applied near the intersection where the first linear electrode 11 and the linear elastic body 321 overlap in the Z-axis direction.

[0075] Subsequently, the detection circuit 70 can sequentially switch the composite capacitor to be measured, thereby detecting the magnitude of the force at all of the multiple intersections where the multiple first linear electrodes 10 and the multiple linear elastic bodies 321 overlap in the Z-axis direction. This makes it possible to realize a pressure sensor 1B with surface resolution in Embodiment 2.

[0076] (2-3) Modified form of Embodiment 2 Embodiment 2 described above is merely one of many embodiments of this disclosure. Embodiment 2 can be modified in various ways depending on the design, etc., as long as the objectives of this disclosure are achieved.

[0077] The following lists some modifications of Embodiment 2. The modifications described below can be combined and applied as appropriate. Note that the pressure sensor 1B of Embodiment 2 may also be referred to as Basic Configuration 2 below.

[0078] (2-3-1) Variation 1 A pressure sensor 1B according to Modification 1 of Embodiment 2 will be described with reference to Figure 10. The pressure sensor 1B according to Modification 1 of Embodiment 2 differs from the pressure sensor 1B of Basic Configuration 2 described above in its circuit configuration, including the detection circuit 70. Except for the circuit configuration including the detection circuit 70, the pressure sensor 1B of Modification 1 has a configuration common to the pressure sensor 1B of Basic Configuration 2, so the same reference numerals are used for common components, and their descriptions are omitted.

[0079] Figure 10 is a schematic circuit diagram of the pressure sensor 1B according to a modified example 1 of Embodiment 2.

[0080] The pressure sensor 1B according to the modified example 1 of Embodiment 2 comprises a switch SW4, switching circuits 101 and 102, and a capacitor Cx.

[0081] The first terminal of capacitor Cx is connected to an AC power supply, and the second terminal of capacitor Cx is connected to the first terminal of switch SW4. Switch SW4 is switched on or off by a detection circuit 70.

[0082] The second terminal of switch SW4 is switched and connected to one of terminals X1 to X3 via the switching circuit 101. More specifically, the detection circuit 70 controls the switching circuit 101 to switch and connect the second terminal of switch SW4 to one of terminals X1 to X3.

[0083] The switching circuit 102 connects one of terminals Y1 to Y3 to the circuit's reference voltage. More specifically, the detection circuit 70 controls the switching circuit 102 to switch one of terminals Y1 to Y3 to the circuit's reference voltage.

[0084] Here, we will describe the operation of the detection circuit 70 when it detects, for example, the force applied to the intersection where the first linear electrode 11 and the linear elastic body 321 overlap in the Z-axis direction.

[0085] The detection circuit 70 controls the switching circuit 101 to connect the terminal X1 provided on the first linear electrode 11 to the second end of the switch SW4. The detection circuit 70 also controls the switching circuit 102 to connect the terminal Y1 provided on the linear elastic body 321 to the circuit's reference voltage.

[0086] In this state, a sinusoidal AC voltage Acos(2πf1·t) is applied from the AC power supply AC through the capacitor Cx to the composite capacitor formed between the first linear electrode 11 and the linear elastic body 321. In other words, the detection circuit 70 connects the AC power supply AC to the composite capacitor Cn to be measured and flows a charging current through the composite capacitor Cn to be measured. Here, if the capacitance of the composite capacitor Cn formed between the first linear electrode 11 and the linear elastic body 321 is C_X1Y1, and the resistance of the ionic material layer 40 between the first linear electrode 11 and the linear elastic body 321 is R1, then the time constant of the RC circuit composed of the composite capacitor Cn and the resistor R1 is (R1·C_X1Y1). Here, the frequency of the AC power supply AC is set such that the time of half a period (1 / f1) of the AC voltage A1·cos(2πf1·t) is longer than the time constant (R1·C_X1Y1). In other words, the half-cycle time of the AC voltage of the AC power supply is set to be longer than the time constant of the circuit including the synthetic capacitor and the ionic material layer 40 being measured.

[0087] The detection circuit 70 detects the amplitude of the voltage Vm input from the buffer amplifier B1. Here, if the capacitance of capacitor Cx is CX, the voltage Vm is expressed by the following equation (1). Vm=CX / (CX+C_X1Y1)·A1·cos(2πf1·t) …(1)

[0088] Since the capacitance value CX of capacitor Cx is set in advance in the detection circuit 70, the detection circuit 70 can determine the magnitude of the capacitance C_X1Y1 of the composite capacitor Cn formed between the first linear electrode 11 and the linear elastic body 321 based on the detection result of the amplitude of the voltage Vm. Once the magnitude of capacitance C_X1Y1 is determined, the detection circuit 70 can detect the magnitude of the force applied to the intersection portion where the first linear electrode 11 and the linear elastic body 321 overlap in the Z-axis direction from this capacitance C_X1Y1.

[0089] Subsequently, the detection circuit 70 can sequentially switch the composite capacitor to be measured, thereby detecting the magnitude of the force at all of the multiple intersections where the multiple first linear electrodes 10 and the multiple linear elastic bodies 321 overlap in the Z-axis direction. This makes it possible to realize a pressure sensor 1B with surface resolution even in the modified example 1 of Embodiment 2.

[0090] (2-3-2) Modification example 2 A pressure sensor 1B according to Modification 2 of Embodiment 2 will be described with reference to Figures 11 to 13. The pressure sensor 1B according to Modification 2 of Embodiment 2 differs from the pressure sensor 1B according to Basic Configuration 2 or Modification 1 of Embodiment 2 in that each of the multiple elastic bodies 30 includes multiple individual elastic bodies 3n corresponding to multiple composite capacitors. The pressure sensor 1B of Modification 2 has a configuration common to the pressure sensor 1B of Basic Configuration 2 described above, except for the configuration of the elastic bodies 30, so the same reference numerals are used for common components and their descriptions are omitted.

[0091] Figure 11 is a cross-sectional view of the pressure sensor 1B according to modified example 2 of Embodiment 2. Figure 12 is a plan view of the pressure sensor 1B according to modified example 2 of Embodiment 2. Figure 13 is a bottom view of the pressure sensor 1B according to modified example 2 of Embodiment 2.

[0092] In the pressure sensor 1B according to the modified example 2, rectangular plate-shaped second electrodes 210, 220, and 230 are arranged parallel to the second surface 42 of the ionic material layer 40, with the second direction (X-axis direction) as the longitudinal direction. The second electrodes 210, 220, and 230 are spaced apart in the first direction (Y-axis direction). Each of the second electrodes 210, 220, and 230 is provided with an individual elastic body 3n at a position opposite to each of the first linear electrodes 11, 12, and 13. The multiple individual elastic bodies 3n are separated from each other.

[0093] Each of the multiple individual elastic bodies 3n provided on the second electrodes 210, 220, and 230 faces one of the first linear electrodes 11, 12, or 13. Therefore, multiple composite capacitors Cn are formed between the multiple first linear electrodes 11, 12, and 13 and the multiple individual elastic bodies 3n. The detection circuit 70 sequentially measures the capacitance of the multiple composite capacitors Cn formed between the multiple first linear electrodes 11, 12, and 13 and the multiple individual elastic bodies 3n. Based on the measurement results of the capacitance of the composite capacitors Cn, the detection circuit 70 can sequentially detect the force applied near multiple intersections where the multiple first linear electrodes 11, 12, and 13 and the multiple individual elastic bodies 3n overlap in the Z-axis direction.

[0094] (2-3-3) Other variations The structure of the pressure sensor 1B described in Basic Configuration 2 and Modifications 1 and 2 of Embodiment 2 is an example, and the shape and number of the first electrodes 10 can be changed as appropriate. The shape and number of the elastic bodies 30 can also be changed as appropriate, and the shape and number of the second electrodes 20 connected to the elastic bodies 30 can also be changed as appropriate.

[0095] (3) Embodiment 3 The pressure sensor 1 according to Embodiment 3 will be described in detail below with reference to Figures 14 to 17. In the following, the pressure sensor 1 of Embodiment 3 may also be referred to as pressure sensor 1C. In addition, in the pressure sensor 1C of Embodiment 3, components common to the pressure sensor 1A of Embodiment 1 or the pressure sensor 1B of Embodiment 2 are denoted by the same reference numerals, and their descriptions are omitted.

[0096] (3-1) Composition The pressure sensor 1C of Embodiment 3 comprises an ionic material layer 40, a first electrode 10, an elastic body 30, a second electrode 20, and a flexible substrate 50, similar to Embodiment 1.

[0097] In the pressure sensor 1C of the modified example 3, the entire second surface 42 of the ionic material layer 40 faces the elastic body 30. Multiple protrusions 301 that can contact the ionic material layer 40 are provided on the portion of the elastic body 30 facing the ionic material layer 40, arranged at equal intervals in the second direction.

[0098] Furthermore, multiple (for example, three) first electrodes 10 are provided on the first surface 41 of the ionic material layer 40 at intervals in the second direction. That is, the region where the ionic material layer 40 and the first electrodes 10 face each other is narrower than the region where the ionic material layer 40 and the elastic body 30 face each other. In other words, the dimensions of the first electrodes 10 in the second direction are set to be smaller than the dimensions of the elastic body 30 in the second direction, so that a part of the elastic body 30 does not face the first electrodes 10 in the direction perpendicular to the first surface 41 of the ionic material layer 40 (Z-axis direction).

[0099] As a result, some of the multiple protrusions 301 provided on the elastic body 30 overlap with the first electrode 10 in the Z-axis direction, while other protrusions 301 are provided so as not to overlap with the first electrode 10 in the Z-axis direction.

[0100] Figure 15 is an equivalent circuit diagram of a portion of the pressure sensor 1C. In the pressure sensor 1C, multiple (e.g., three) composite capacitors C1, C2, C3 are formed between each of the multiple (e.g., three) first electrodes 11, 12, 13 and the elastic body 30.

[0101] Here, the composite capacitor C1 includes a first capacitor C11 formed between the first electrode 11 and the ionic material layer 40, and a second capacitor C21 formed between the ionic material layer 40 and the elastic body 30. The second capacitor C21 is the combined capacitance of the second capacitors C210, C211, and C212. The second capacitor C210 is formed between a protrusion 301 of the elastic body 30 directly below the first electrode 11 and the ionic material layer 40. The second capacitors C211 and C212 are formed, respectively, between two protrusions 301 on the left and right of the protrusion 301 directly below the first electrode 11 and the ionic material layer 40. Here, the first capacitor C11 and the second capacitors C210, C211, and C212 are connected via resistors r1, r2, and r2, which are the resistive components of the ionic material layer 40. The resistance values ​​of resistors r1, r2, and r2 are proportional to the distance between the three protrusions 301 on which the second capacitors C210, C211, and C212 are formed, and the first electrode 11. The resistance value of resistor r2 is several times to more than ten times the resistance value of resistor r1.

[0102] Similarly, the composite capacitor C2 includes a first capacitor C12 formed between the first electrode 12 and the ionic material layer 40, and a second capacitor C22 formed between the ionic material layer 40 and the elastic body 30. The second capacitor C22 is the combined capacitance of the second capacitors C220, C221, and C222. The second capacitor C220 is formed between the protrusion 301 of the elastic body 30 directly below the first electrode 12 and the ionic material layer 40. The second capacitors C221 and C222 are formed, respectively, between the two protrusions 301 on the left and right of the protrusion 301 directly below the first electrode 11 and the ionic material layer 40. Here, the first capacitor C12 and the second capacitors C220, C221, and C222 are connected via resistors r1, r2, and r2, which are the resistive components of the ionic material layer 40. The resistance value of resistor r2 is several times to more than ten times the resistance value of resistor r1.

[0103] Furthermore, the composite capacitor C3 includes a first capacitor C13 formed between the first electrode 13 and the ionic material layer 40, and a second capacitor C23 formed between the ionic material layer 40 and the elastic body 30. The second capacitor C23 is the combined capacitance of the second capacitors C230, C231, and C232. The second capacitor C230 is formed between the protrusion 301 of the elastic body 30 directly below the first electrode 13 and the ionic material layer 40. The second capacitors C231 and C232 are formed, respectively, between the two protrusions 301 on the left and right of the protrusion 301 directly below the first electrode 13 and the ionic material layer 40. Here, the first capacitor C13 and the second capacitors C230, C231, and C232 are connected via resistors r1, r2, and r2, which are the resistive components of the ionic material layer 40. The resistance value of resistor r2 is several times to more than ten times the resistance value of resistor r1. The resistance value of resistor r2 is several times to more than ten times the resistance value of resistor r1.

[0104] Furthermore, the pressure sensor 1C is equipped with a detection circuit 70 that detects the capacitance of the second capacitors C21, C22, and C23 contained in each of the multiple composite capacitors C1, C2, and C3 (see Figure 16). The pressure sensor 1C is also equipped with switches SW1 and SW3, a DC power supply E1, a capacitor Cx, and a buffer amplifier B1.

[0105] Switch SW1 is connected between a DC power supply E1, which outputs a DC voltage of a predetermined value, and a capacitor Cx. Switch SW1 is switched on / off by a detection circuit 70.

[0106] The first terminal of capacitor Cx is connected to the circuit's common voltage (circuit ground), and the second terminal of capacitor Cx is connected to switch SW1.

[0107] The first terminal of switch SW3 is connected to the connection point between switch SW1 and capacitor Cx, and the second terminal of switch SW3 is connected to one of terminals X1 to X3. The detection circuit 70 switches the connection destination of the second terminal of switch SW3. Figure 16 shows the state in which the second terminal of switch SW3 is connected to terminal X1. In this case, the second terminal of switch SW3 is connected to the composite capacitor C1 formed between the first electrode 11 connected to terminal X1 and the elastic body 30 connected to terminal Y1. This composite capacitor C1 includes the first capacitor C11 formed between the first electrode 11 and the ionic material layer 40, and the second capacitors C210, C211, and C212 formed between the elastic body 30 and the ionic material layer 40. Terminal Y1 is connected to the common voltage of the circuit.

[0108] Buffer amplifier B1 outputs the voltage Vm at the connection point between switch SW1 and capacitor Cx to detection circuit 70.

[0109] The detection circuit 70 detects the capacitance of the second capacitor C2n to be measured based on the voltage value of the voltage Vm input from the buffer amplifier B1. The detection circuit 70 measures the capacitance of the second capacitor C2n contained in each of the multiple composite capacitors Cn. Then, by measuring the capacitance of the second capacitor C2n contained in each of the multiple composite capacitors Cn, the detection circuit 70 detects the magnitude of the force applied to the elastic body 30 from the capacitance measurement results.

[0110] (3-2) Operation Description The operation of the detection circuit 70 when it detects, for example, the pressure applied near the first electrode 11 will be explained below with reference to Figure 17, etc. In this case, the detection circuit 70 detects the capacitance of the second capacitors C210~C212 that are formed near the position of the first electrode 11, and detects the pressure applied near the first electrode 11 based on the capacitance of the second capacitors C210~C212.

[0111] More specifically, the detection circuit 70 controls switch SW3 to ensure that all terminals X1 to X3 are not connected to capacitor Cx. Then, the detection circuit 70 turns switch SW1 ON for a predetermined time (for example, from time t11 to time t12 in Figure 17) to charge capacitor Cx to the output voltage V1 of the DC power supply E1.

[0112] Next, the detection circuit 70 does not supply charging current to one or more of the multiple composite capacitors Cn other than the composite capacitor Cn being measured, and supplies charging current only to the composite capacitor Cn being measured. More specifically, the detection circuit 70 connects a capacitor Cx charged to a predetermined voltage to the composite capacitor Cn being measured, thereby supplying charging current to the composite capacitor Cn being measured. For example, the detection circuit 70 connects the composite capacitor Cn being measured to capacitor Cx by connecting the second terminal of the switch SW3 to the terminal (any of terminals X1 to X3) to which the composite capacitor Cn being measured is connected. At this time, charging current flows from capacitor Cx to the composite capacitor Cn being measured, and the voltage Vm across the capacitor Cx gradually decreases.

[0113] The detection circuit 70 measures the voltage between the second electrode 20 and the first electrode 11 at the measurement timing after a charging current has been passed through the composite capacitor Cn to be measured. Based on the measurement result of the voltage value, the detection circuit 70 then detects the capacitance of the second capacitor C2n included in the composite capacitor Cn to be measured.

[0114] Here, the detection circuit 70 can change the range of the synthetic capacitor Cn to be measured by changing the charging time during which a charging current is passed to the synthetic capacitor Cn to be measured.

[0115] For example, the detection circuit 70 detects the capacitance of the composite capacitor Cn when the charging time CT11 (see Figure 17) is set to be longer than the first time constant and shorter than the second time constant. Here, the first time constant is the time constant of the RC circuit including the second capacitor C210 and the first capacitor C11 between the protrusion 301 directly below the first electrode 11 and the ionic material layer 40. The second time constant is the time constant of the RC circuit including the second capacitors C210~C212 and the first capacitor C11 between the protrusions 301 directly below and on both sides of the first electrode 11 and the ionic material layer 40. The detection circuit 70 controls the switch SW3 to turn ON during the charging time CT11 from time t13 to time t14, thereby supplying a charging current to the composite capacitor Cn to be measured. The detection circuit 70 then measures the voltage Vm of the capacitor Cx after supplying a charging current for the charging time CT11, and detects the capacitance of the composite capacitor Cn based on the measured voltage value, thereby measuring the second capacitor C210 located between the protrusion 301 directly below the first electrode 11 and the ionic material layer 40. Based on the measurement result of the capacitance of the second capacitor C210, the detection circuit 70 can detect the force applied to the position above the first electrode 11 on the flexible substrate 50.

[0116] Furthermore, the detection circuit 70 detects the capacitance of the composite capacitor Cn with the charging time CT12 (see Figure 17) set to a time longer than the second time constant. The detection circuit 70 controls switch SW3 to turn ON during the charging time CT12 from time t15 to time t16, thereby flowing a charging current to the composite capacitor Cn to be measured. After flowing the charging current for the charging time CT12, the detection circuit 70 measures the voltage value Vm of the capacitor Cx and detects the capacitance of the composite capacitor Cn based on the measured voltage value, thereby detecting the combined capacitance of the second capacitors C210, C211, and C212 between the protrusions 301 directly below and on both sides of the first electrode 11 and the ionic material layer 40. Based on the measurement result of the combined capacitance of the second capacitors C210, C211, and C212, the detection circuit 70 can detect the force applied to the flexible substrate 50 above the protrusions 301 directly below and on both sides of the first electrode 11.

[0117] Thus, in this embodiment, the detection circuit 70 can change the measurement range of the synthetic capacitor Cn by adjusting the charging time for charging the synthetic capacitor Cn to be measured. Therefore, the pressure sensor 1C can detect the application of force even in areas where the ionic material layer 40 and the first electrode 10 are not facing each other, as long as the ionic material layer 40 and the elastic body 30 are facing each other, thus expanding the range in which force can be detected.

[0118] (3-3) Modified form of Embodiment 3 Embodiment 3 described above is merely one of many embodiments of this disclosure. Embodiment 3 can be modified in various ways depending on the design, etc., as long as the objectives of this disclosure are achieved.

[0119] The following lists some modifications of Embodiment 3. The modifications described below can be combined and applied as appropriate. Note that the pressure sensor 1C of Embodiment 3 may also be referred to as Basic Configuration 3 below.

[0120] (3-3-1) Variation 1 Figure 18 is a schematic circuit diagram of a pressure sensor 1C according to a modified example 1 of Embodiment 3.

[0121] The pressure sensor 1C according to the modified example 1 of Embodiment 3 comprises a switch SW4 and a capacitor Cm.

[0122] The first terminal of capacitor Cm is connected to an AC power supply, and the second terminal of capacitor Cm is connected to the first terminal of switch SW4. Switch SW4 is switched on or off by the detection circuit 70.

[0123] The second terminal of switch SW4 is switched and connected to one of terminals X1 to X3 via a switching circuit (not shown). More specifically, the detection circuit 70 controls the switching circuit to switch and connect the second terminal of switch SW4 to one of terminals X1 to X3.

[0124] Here, we will describe the operation of the detection circuit 70 when it detects, for example, the pressure applied near the position of the first electrode 11.

[0125] The detection circuit 70 controls the switching circuit to connect the terminal X1 provided on the first electrode 11 to the second terminal of the switch SW4.

[0126] In this state, a sinusoidal AC voltage Acos(2πf1·t) is applied from the AC power supply AC through the capacitor Cm to the composite capacitor Cn formed between the first electrode 11 and the elastic body 30. In other words, the detection circuit 70 connects the AC power supply AC to the composite capacitor Cn to be measured and allows a charging current to flow through the composite capacitor Cn to be measured. Here, if the capacitance of the composite capacitor Cn formed between the first electrode 11 and the elastic body 30 is C_X1Y1, and the resistance of the ionic material layer 40 between the first electrode 11 and the elastic body 30 is R1, then the time constant of the RC circuit composed of the composite capacitor Cn and the resistor R1 is (R1·C_X1Y1). The time of half a period (1 / 2f1) of the AC voltage A1·cos(2πf1·t) is set to be longer than the time constant (R1·C_X1Y1). In other words, the half-cycle time of the AC voltage of the AC power supply is set to be longer than the time constant of the circuit including the synthetic capacitor and the ionic material layer 40 being measured.

[0127] The detection circuit 70 detects the amplitude of the voltage Vm input from the buffer amplifier B1. Here, if the capacitance of the capacitor Cm is CM, the voltage Vm is expressed by the following equation (2). Vm=CM / (CM+C_X1Y1)·A1·cos(2πf1·t) …(2)

[0128] Since the capacitance value of capacitor Cm is pre-set in the detection circuit 70, the detection circuit 70 can determine the capacitance C_X1Y1 of the composite capacitor Cn formed between the first electrode 11 and the elastic body 30 based on the detection result of the amplitude of the voltage Vm. Once the detection circuit 70 determines the capacitance C_X1Y1 of the composite capacitor Cn formed between the first electrode 11 and the elastic body 30, it can detect the pressure applied near the position of the first electrode 11 from this capacitance C_X1Y1.

[0129] Subsequently, the detection circuit 70 can detect the pressure applied near each of the multiple first electrodes 10 by sequentially switching the composite capacitors to be measured.

[0130] (3-3-2) Other variations In the pressure sensor 1C of basic configuration 3, the elastic body 30 is formed as a single unit, but the elastic body 30 may be divided into multiple parts.

[0131] For example, as shown in Figure 1 of Embodiment 1, the elastic body 30 may include a plurality of individual elastic bodies 3n corresponding to each of the plurality of composite capacitors. The plurality of individual elastic bodies 3n are separated from each other, and each of the plurality of individual elastic bodies 3n may be provided with an individual second electrode 20.

[0132] Since the elastic body 30 includes multiple individual elastic bodies 3n, a pressure sensor 1C capable of improving surface resolution can be provided.

[0133] Furthermore, as shown in Figures 6 and 7 of Embodiment 2, the pressure sensor 1B may have first electrodes 11, 12, and 13 as linear electrodes with the Y-axis direction as its longitudinal direction, and multiple elastic bodies 30 may be arranged at intervals in the Y-axis direction so as to intersect with the multiple linear electrodes.

[0134] In other words, the first electrode 10 may include a plurality of first linear electrodes whose longitudinal direction is parallel to the first surface 41 of the ionic material layer 40. The plurality of first linear electrodes are arranged on the first surface 41 of the ionic material layer 40 with spacing between them in a second direction that is parallel to the first surface 41 and perpendicular to the first direction. Furthermore, a plurality of elastic bodies 30 may be arranged with spacing between them in the first direction, so that a plurality of composite capacitors are arranged along the first and second directions, respectively. In this case, the pressure sensor 1C can detect the pressure applied at a position where the plurality of first linear electrodes and the plurality of conductors overlap in the Z-axis direction.

[0135] (4) Embodiment 4 The pressure sensor 1 according to Embodiment 4 will be described in detail below with reference to Figures 19 to 21. In the following, the pressure sensor 1 of Embodiment 4 may also be referred to as pressure sensor 1D.

[0136] The pressure sensor 1D of Embodiment 4 differs from the pressure sensor 1A of Embodiment 1 in that the first electrode 10 is provided only on the outer edge portion of the first surface 41 of the ionic material layer 40. In the pressure sensor 1D of Embodiment 4, components common to the pressure sensor 1A of Embodiment 1, the pressure sensor 1B of Embodiment 2, or the pressure sensor 1C of Embodiment 3 are denoted by the same reference numerals, and their descriptions are omitted.

[0137] The pressure sensor 1D comprises multiple first electrodes 10. The multiple first electrodes 10 are arranged at intervals from each other on the outer edge of the ionic material layer 40.

[0138] For example, the pressure sensor 1D has two first electrodes 10, as shown in Figures 19 and 20. The two first electrodes 10 are located on the outer edges of the first surface 41 of the ionic material layer 40, facing each other in the X-axis direction. In the following description, when distinguishing between the two first electrodes 10, the left first electrode 10 may be referred to as the first electrode 111, and the right first electrode 10 as the first electrode 112.

[0139] The elastic body 30 is positioned to face the second surface 42 of the ionic material layer 40. Multiple V-shaped protrusions 301 are provided on the surface of the elastic body 30 facing the ionic material layer 40, arranged at equal intervals in the second direction.

[0140] In the pressure sensor 1D of Embodiment 4, the lower surface of the second electrode 20 provided on the lower surface of the elastic body 30, or a flexible substrate (not shown) provided on the lower surface of the second electrode 20, becomes the contact surface that comes into contact with the object. There is a gap between the elastic body 30 and the ionic material layer 40, and when an upward force is applied to the elastic body 30 by an object coming into contact with the contact surface, the projection 301 above the force application point comes into contact with the ionic material layer 40.

[0141] The pressure sensor 1D further includes a detection circuit 70 (see Figure 21). The pressure sensor 1D also further includes a switch SW5, a DC power supply E1, a resistor R100, and a buffer amplifier B1.

[0142] Figure 21 shows the equivalent circuit when a force is applied to the elastic body 30, causing one of the protrusions 301 to come into contact with the ionic material layer 40. In this case, a first capacitor C11 is formed between the first electrode 111 and the ionic material layer 40, and a first capacitor C12 is formed between the first electrode 112 and the ionic material layer 40. A second capacitor C21 is also formed between the ionic material layer 40 and the elastic body 30. The first capacitor C11 is connected to the second capacitor C21 via a resistor Rx1, which is the resistive component of the ionic material layer 40, and the second capacitor C21 is connected to the second capacitor C21 via a resistor Rx2, which is the resistive component of the ionic material layer 40. Here, the resistor Rx1 is the resistive component of the ionic material layer 40 between the contact position with the elastic body 30 on the second surface 42 of the ionic material layer 40 and the first electrode 111. Resistance Rx2 is the resistance component of the ionic material layer 40 between the contact position with the elastic body 30 on the second surface 42 of the ionic material layer 40 and the first electrode 112.

[0143] Switch SW5 has a common terminal and two selectable terminals (a first selectable terminal and a second selectable terminal). The common terminal of switch SW5 is connected to the DC power supply E1 via resistor R100. The first selectable terminal of switch SW5 is connected to terminal X1 which is connected to the first electrode 111. The second selectable terminal of switch SW5 is connected to terminal X2 which is connected to the first electrode 112. Switch SW5's internal contacts are switched to either the first selectable terminal or the second selectable terminal in response to a control signal from the detection circuit 70.

[0144] Buffer amplifier B1 outputs the voltage Vm at the connection point between switch SW5 and resistor R100 to detection circuit 70.

[0145] The detection circuit 70 detects the force generated when an object comes into contact with the contact surface and the contact position based on the voltage value of the voltage Vm input from the buffer amplifier B1.

[0146] The detection circuit 70 determines the force application position based on the impedance between each of the multiple first electrodes 111, 112 and the second electrode 20.

[0147] For example, the detection circuit 70 controls the switch SW5 to connect the internal contacts to the first switching terminal and immediately after the connection determines the current value I of the current flowing through the pressure sensor 1D. Here, if the voltage value of the DC power supply E1 is V1 and the resistance value of the resistor R100 is r100, then the current value I of the current flowing through the pressure sensor 1D is I = (E1 - Vm) / r100. Once the detection circuit 70 determines the current value I of the current flowing through the pressure sensor 1D, it determines the resistance value of the resistor Rx1 based on the current value I, and then determines the distance from the first electrode 111 to the force application position (the contact position between the ionic material layer 40 and the elastic body 30) based on the resistance value of the resistor Rx1.

[0148] Next, the detection circuit 70 controls the switch SW5 to connect the internal contacts to the second switching terminal and determines the current value I of the current flowing through the pressure sensor 1D immediately after the connection. Based on the current value I, the detection circuit 70 determines the resistance value of resistor Rx2 and, based on the resistance value of resistor Rx2, determines the distance from the first electrode 112 to the force application position (the contact position between the ionic material layer 40 and the elastic body 30).

[0149] The detection circuit 70 determines the distance from the two first electrodes 111 and 112 to the force application point, and then controls the switch SW5 to switch its internal contact to terminal X1 connected to the first electrode closest to the force application point (first electrode 111 in the example of Figure 19). As a result, a charging current flows from the DC power supply E1 to the pressure sensor 1D via the resistor R100 and the switch SW5, and the combined capacitor C1, which includes the first capacitor C11 and the second capacitor C21, is charged. In other words, the detection circuit 70 selects the first electrode 111 closest to the force application point from among the multiple first electrodes 111 and 112 as the first electrode 111 to be measured, and flows a charging current between the first electrode 111 to be measured and the second electrode 20.

[0150] The detection circuit 70 then measures the voltage value (voltage value Vm) between the first electrode 111 and the second electrode 20 of the object to be measured at a measurement timing after a charging current has been applied for a charging time longer than the time constant of the circuit including the composite capacitor C1 between the first electrode 111 and the second electrode 20 and the ionic material layer 40. Here, the composite capacitor C1 between the first electrode 111 and the second electrode 20 of the object to be measured is the combined capacitance of the first capacitor C11 between the first electrode 111 and the ionic material layer 40 and the second capacitor C21 between the ionic material layer 40 and the elastic body 30.

[0151] The detection circuit 70 then detects the capacitance of the second capacitor C21 included in the composite capacitor C1 based on the voltage value measured at the measurement timing. The detection circuit 70 has pre-programmed relational formulas that represent the correspondence between the capacitance of the second capacitor C21 and the force applied to the elastic body 30. Therefore, the detection circuit 70 can detect the position and magnitude of the force applied to the elastic body 30 based on the measurement result of the capacitance of the second capacitor C21 and the relational formula that represents the correspondence between the capacitance of the second capacitor C21 and the force applied to the elastic body 30.

[0152] In the pressure sensor 1D of Embodiment 4, one first electrode 10 is provided on each of two opposing sides of the rectangular ionic material layer 40. However, multiple first electrodes 10 may be provided on each of two opposing sides of the rectangular ionic material layer 40. Also, as shown in Figure 22, multiple first electrodes 10 may be provided on each of the four sides of the rectangular ionic material layer 40.

[0153] In this case as well, the detection circuit 70 connects multiple first electrodes 10 to the DC power supply E1 in sequence, detects the current value flowing through the pressure sensor 1D immediately after connection, and detects the first electrode 10 closest to the force application position based on the current value immediately after connection. The detection circuit 70 then connects the DC power supply E1 to the first electrode 10 closest to the force application position to charge the composite capacitor between the first electrode 10 and the second electrode 20, and measures the voltage value of voltage Vm at a predetermined measurement timing. The detection circuit 70 then determines the capacitance of the composite capacitor from the voltage value of voltage Vm, and detects the magnitude of the force applied to the contact surface based on the capacitance of the composite capacitor.

[0154] In the pressure sensor 1D of Embodiment 4, multiple first electrodes 10 are placed on the outer edge of the ionic material layer 40, and the first electrode 10 closest to the force application position is determined from among the multiple first electrodes 10. Then, by passing a charging current through the composite capacitor formed between the first electrode 10 closest to the force application position and the second electrode 20, the capacitance of the composite capacitor is determined, and the magnitude of the force is determined from the capacitance of the composite capacitor.

[0155] Thus, in the pressure sensor 1D of Embodiment 4, since it is sufficient to arrange multiple first electrodes 10 on the outer edge of the ionic material layer 40, there is an advantage in that the number of electrodes (including the first electrode 10 and the second electrode 20) provided in the pressure sensor 1D can be reduced. Furthermore, since the capacitance of the composite capacitor is determined by flowing a charging current only through the composite capacitor formed between the first electrode 10 and the second electrode 20 closest to the force application position, the detection time can be shortened compared to the case where a charging current is flowed through each of the multiple composite capacitors formed between multiple first electrodes 10 and second electrodes 20.

[0156] In the pressure sensor 1D of Embodiment 4, the position and number of the first electrodes 10 can be changed as appropriate.

[0157] (summary) Based on the embodiments described above, the following aspects are disclosed.

[0158] A pressure sensor (1) in a first embodiment comprises an ionic material layer (40), a first electrode (10), an elastic body (30), and a second electrode (20). The first electrode (10) is provided on a first surface (41) in the thickness direction of the ionic material layer (40). The elastic body (30) is conductive and is positioned opposite to a second surface (42) in the thickness direction of the ionic material layer (40). The second electrode (20) is connected to the elastic body (30). There are multiple first electrodes (10) and multiple elastic bodies (30) so that multiple composite capacitors (Cn) can be formed by connecting multiple composite capacitors (Cn) in parallel to the first electrode (10). Each of the multiple composite capacitors (Cn) includes a first capacitor (C1n) formed between the first electrode (10) and the ionic material layer (40), and a second capacitor (C2n) formed between the ionic material layer (40) and the elastic body (30). The ionic material layer (40) is common to multiple composite capacitors (Cn). The capacitance of the second capacitor (C2n) changes as the contact area between the elastic body (30) and the ionic material layer (40) changes in response to the pressure applied to the elastic body (30).

[0159] According to this embodiment, it becomes easier to detect changes in the capacitance of the second capacitor (C2n) due to the application of force, thereby improving detection sensitivity.

[0160] In the pressure sensor (1) of the second embodiment, the elastic body (30) includes a plurality of individual elastic bodies (3n) corresponding to each of a plurality of composite capacitors (Cn). The plurality of individual elastic bodies (3n) are separated from each other. Each of the plurality of individual elastic bodies (3n) is provided with an individual second electrode (20).

[0161] According to this embodiment, the resolution of the force application position can be determined by the size of each individual elastic body (3n).

[0162] In the third embodiment of the pressure sensor (1), in the second embodiment, a plurality of individual elastic bodies (3n) are arranged two-dimensionally in a plane parallel to the second surface (42) of the ionic material layer (40).

[0163] According to this embodiment, the position of force application can be detected in two dimensions within a two-dimensional region where multiple individual elastic bodies (3n) are arranged.

[0164] The pressure sensor (1) of the fourth embodiment further comprises a detection circuit (70) in the second or third embodiment. The detection circuit (70) detects the capacitance of the second capacitor (C2n) contained in each of the plurality of composite capacitors (Cn). The detection circuit (70) does not supply charging current to one or more composite capacitors (Cn) other than the composite capacitor (Cn) to be measured, and supplies charging current only to the composite capacitor (Cn) to be measured. The detection circuit (70) measures the voltage value between the second electrode (20) and the first electrode (10) at a measurement timing after supplying charging current for a charging time longer than the time constant of the circuit including the composite capacitor (Cn) to be measured and the ionic material layer (40). Based on the measurement result of the voltage value, the detection circuit (70) detects the capacitance of the second capacitor (C2n) contained in the composite capacitor (Cn) to be measured.

[0165] According to this embodiment, detection sensitivity can be improved.

[0166] The pressure sensor (1) of the fifth embodiment comprises a plurality of elastic bodies (30) in the first embodiment. The first electrode (10) includes a plurality of first linear electrodes whose longitudinal direction is parallel to the first surface (41) of the ionic material layer (40). The plurality of first linear electrodes are arranged on the first surface (41) of the ionic material layer (40) with spacing in a second direction that is parallel to the first surface (41) and perpendicular to the first direction. The plurality of elastic bodies (30) are arranged with spacing in the first direction so that a plurality of composite capacitors (Cn) are arranged along the first and second directions, respectively.

[0167] According to this embodiment, the position where force is applied can be detected in two dimensions.

[0168] In the pressure sensor (1) of the sixth embodiment, as in the fifth embodiment, each of the plurality of elastic bodies (30) includes a plurality of individual elastic bodies (3n) corresponding to a plurality of composite capacitors (Cn). The plurality of individual elastic bodies (3n) are separated from each other.

[0169] According to this embodiment, the resolution of the force application position can be determined by the size of each individual elastic body (3n).

[0170] In the pressure sensor (1) of the seventh embodiment, as in the fifth embodiment, the plurality of elastic bodies (30) include a plurality of linear elastic bodies (32n) whose longitudinal direction is the second direction. Each of the plurality of linear elastic bodies (32n) has a plurality of portions that overlap with a plurality of first linear electrodes in the direction normal to the second surface (42) that are integrated together.

[0171] According to this embodiment, the position where force is applied can be detected in two dimensions.

[0172] The pressure sensor (1) of the eighth embodiment further comprises a detection circuit (70) in any of the fifth to seventh embodiments. The detection circuit (70) detects the capacitance of the second capacitor (C2n) contained in each of the plurality of composite capacitors (Cn). The detection circuit (70) does not supply charging current to one or more composite capacitors (Cn) other than the composite capacitor (Cn) to be measured, and supplies charging current only to the composite capacitor (Cn) to be measured. The detection circuit (70) measures the voltage value between the second electrode (20) and the first electrode (10) at a measurement timing after supplying charging current for a charging time longer than the time constant of the composite capacitor (Cn) to be measured. Based on the measurement result of the voltage value, the detection circuit (70) detects the capacitance of the second capacitor (C2n) contained in the composite capacitor (Cn) to be measured.

[0173] According to this embodiment, detection sensitivity can be improved.

[0174] In the pressure sensor (1) of the ninth embodiment, as in the eighth embodiment, the detection circuit (70) connects a capacitor (CX) charged to a predetermined voltage to the composite capacitor (Cn) to be measured, and flows a charging current to the composite capacitor (Cn) to be measured.

[0175] According to this embodiment, the capacitance of the second capacitor (C2n) can be detected from the response characteristics when a DC voltage is applied to the composite capacitor (Cn).

[0176] In the pressure sensor (1) of the tenth embodiment, in the eighth embodiment, the detection circuit (70) connects an AC power supply (AC) to the composite capacitor (Cn) to be measured and supplies a charging current to the composite capacitor (Cn). Half a period of the AC voltage of the AC power supply (AC) is longer than the time constant of the circuit including the composite capacitor (Cn) and the ionic material layer (40).

[0177] According to this embodiment, the capacitance of the second capacitor (C2n) can be detected from the response characteristics when an AC voltage is applied to the composite capacitor (Cn).

[0178] In the pressure sensor (1) of the eleventh embodiment, the region in which the ionic material layer (40) and the first electrode (10) face each other is narrower than the region in which the ionic material layer (40) and the elastic body (30) face each other, as in the first embodiment.

[0179] According to this embodiment, as long as the ionic material layer (40) and the elastic body (30) are facing each other, the applied force can be detected even in areas where the ionic material layer (40) and the first electrode (10) are not facing each other, thus expanding the area in which force can be detected.

[0180] In the pressure sensor (1) of the twelfth embodiment, as in the eleventh embodiment, the elastic body (30) includes a plurality of individual elastic bodies (3n) corresponding to each of a plurality of composite capacitors (Cn). The plurality of individual elastic bodies (3n) are separated from each other. Each of the plurality of individual elastic bodies (3n) is provided with an individual second electrode (20).

[0181] According to this embodiment, the resolution of the force application position can be determined by the size of each individual elastic body (3n).

[0182] In the pressure sensor (1) of the 13th embodiment, a plurality of elastic bodies (30) are provided, as in the 11th embodiment. The first electrode (10) includes a plurality of first linear electrodes whose longitudinal direction is parallel to the first surface (41) of the ionic material layer (40). The plurality of first linear electrodes are arranged on the first surface (41) of the ionic material layer (40) with spacing in a second direction that is parallel to the first surface (41) and perpendicular to the first direction. The plurality of elastic bodies (30) are arranged with spacing in the first direction, so that a plurality of composite capacitors (Cn) are arranged along the first and second directions, respectively.

[0183] According to this embodiment, the position where force is applied can be detected in two dimensions.

[0184] The pressure sensor (1) of the 14th embodiment further comprises a detection circuit (70) in any of the 11th to 13th embodiments. The detection circuit (70) detects the capacitance of a second capacitor (C2n) contained in each of a plurality of composite capacitors (Cn). The detection circuit (70) does not supply charging current to one or more composite capacitors (Cn) other than the composite capacitor (Cn) to be measured, and supplies charging current only to the composite capacitor (Cn) to be measured. The detection circuit (70) measures the voltage value between the second electrode (20) and the first electrode (10) at the measurement timing after supplying charging current to the composite capacitor (Cn) to be measured. Based on the measurement result of the voltage value, the detection circuit (70) detects the capacitance of the second capacitor (C2n) contained in the composite capacitor (Cn) to be measured. The detection circuit (70) can change the range of the composite capacitor (Cn) to be measured by changing the charging time during which a charging current is passed through the composite capacitor (Cn) to be measured.

[0185] According to this embodiment, detection sensitivity can be improved.

[0186] In the pressure sensor (1) of the 15th embodiment, in the 14th embodiment, the detection circuit (70) connects a capacitor (CX) charged to a predetermined voltage to the composite capacitor (Cn) to be measured, and flows a charging current to the composite capacitor (Cn) to be measured.

[0187] According to this embodiment, the capacitance of the second capacitor (C2n) can be detected from the response characteristics when a DC voltage is applied to the composite capacitor (Cn).

[0188] In the pressure sensor (1) of the 16th embodiment, in the 14th embodiment, the detection circuit (70) connects an AC power supply (AC) to the composite capacitor (Cn) to be measured and supplies a charging current to the composite capacitor (Cn). Half a period of the AC voltage of the AC power supply (AC) is longer than the time constant of the composite capacitor (Cn) to be measured.

[0189] According to this embodiment, the capacitance of the second capacitor (C2n) can be detected from the response characteristics when an AC voltage is applied to the composite capacitor (Cn).

[0190] The pressure sensor (1) of the 17th embodiment comprises a plurality of first electrodes (10) in the first embodiment. The plurality of first electrodes (10) are arranged at intervals from each other on the outer edge portion of the ionic material layer (40).

[0191] According to this embodiment, the number of first electrodes (10) can be reduced because the first electrode (10) only needs to be placed on the outer edge of the ionic material layer (40).

[0192] In the pressure sensor (1) of the 18th embodiment, a detection circuit (70) is further provided in the 17th embodiment, which determines the force application position based on the impedance between each of the plurality of first electrodes (10) and the second electrode (20).

[0193] According to this embodiment, the force application position can be determined while reducing the number of first electrodes (10).

[0194] In the pressure sensor (1) of the 19th embodiment, in the 18th embodiment, the detection circuit (70) selects the first electrode (10) closest to the force application position from among a plurality of first electrodes (10) as the first electrode (10) to be measured, and flows a charging current between the first electrode (10) to be measured and the second electrode (20). The detection circuit (70) measures the voltage value between the first electrode (10) and the second electrode (20) at a measurement timing after flowing the charging current for a charging time longer than the time constant of the circuit including the composite capacitor (Cn) and the ionic material layer (40) between the first electrode (10) and the second electrode (20) to be measured. Based on the measurement result of the voltage value, the detection circuit (70) detects the capacitance of the second capacitor (C2n) included in the composite capacitor (Cn).

[0195] According to this embodiment, the detection sensitivity of the capacitance of the second capacitor (C2n) can be improved.

[0196] The configurations relating to the second to ninth aspects are not essential to the pressure sensor (1) and can be omitted as appropriate. [Explanation of symbols]

[0197] 1. Pressure sensor 3n individual elastic bodies 10 1st electrode 20 2nd electrode 30 Elastic body 32n linear elastic body 40 Ionic material layer 41 Page 1 42 Side 2 70 Detection Circuit AC alternating current power supply C1n First Capacitor C2n Second Reproduction Cn synthetic capacitor CX Capacitor

Claims

1. Ionic material layer, A first electrode provided on the first surface in the thickness direction of the ionic material layer, An elastic body having conductivity and positioned opposite to the second surface in the thickness direction of the ionic material layer, The elastic body comprises a second electrode connected to the elastic body, To enable the formation of multiple composite capacitors connected in parallel to the first electrode, there are multiple instances of at least one of the first electrode and the elastic body. Each of the plurality of composite capacitors includes a first capacitor formed between the first electrode and the ionic material layer, and a second capacitor formed between the ionic material layer and the elastic body. The ionic material layer is common to the plurality of composite capacitors, The capacitance of the second capacitor changes as the contact area between the elastic body and the ionic material layer changes in response to the pressure applied to the elastic body. Pressure sensor.

2. The elastic body includes a plurality of individual elastic bodies corresponding to each of the plurality of composite capacitors, The plurality of individual elastic bodies are separated from each other, Each of the plurality of individual elastic bodies is provided with an individual second electrode. The pressure sensor according to claim 1.

3. The plurality of individual elastic bodies are arranged two-dimensionally in a plane parallel to the second surface of the ionic material layer. The pressure sensor according to claim 2.

4. The system further includes a detection circuit for detecting the capacitance of the second capacitor included in each of the plurality of composite capacitors, The aforementioned detection circuit is Of the aforementioned plurality of composite capacitors, no charging current is passed through one or more composite capacitors other than the composite capacitor to be measured, and a charging current is passed only through the composite capacitor to be measured. At a measurement timing after a charging current has been passed for a charging time longer than the time constant of the circuit including the synthetic capacitor to be measured and the ionic material layer, the voltage value between the second electrode and the first electrode is measured. Based on the measurement result of the voltage value, the capacitance of the second capacitor included in the composite capacitor to be measured is detected. The pressure sensor according to claim 2.

5. The elastic body comprises a plurality of the aforementioned elastic bodies, The first electrode includes a plurality of first linear electrodes whose longitudinal direction is parallel to the first surface of the ionic material layer. The plurality of first linear electrodes are arranged on the first surface of the ionic material layer, spaced apart in a second direction parallel to the first surface and perpendicular to the first direction. The plurality of elastic bodies are arranged so as to be spaced apart in the first direction, such that the plurality of composite capacitors are arranged along the first direction and the second direction, respectively. The pressure sensor according to claim 1.

6. Each of the plurality of elastic bodies includes a plurality of individual elastic bodies corresponding to each of the plurality of composite capacitors, The plurality of individual elastic bodies are separated from each other. The pressure sensor according to claim 5.

7. The plurality of elastic bodies include a plurality of linear elastic bodies whose longitudinal direction is the second direction, Each of the plurality of linear elastic bodies has multiple portions that overlap with the plurality of first linear electrodes in the direction normal to the second surface, which are integrated together. The pressure sensor according to claim 5.

8. The system further includes a detection circuit for detecting the capacitance of the second capacitor included in each of the plurality of composite capacitors, The aforementioned detection circuit is Of the aforementioned plurality of composite capacitors, no charging current is passed through one or more composite capacitors other than the composite capacitor to be measured, and a charging current is passed only through the composite capacitor to be measured. At a measurement timing after a charging current has been applied for a charging time longer than the time constant of the composite capacitor to be measured, the voltage value between the second electrode and the first electrode is measured. Based on the measurement result of the voltage value, the capacitance of the second capacitor included in the composite capacitor to be measured is detected. The pressure sensor according to claim 5.

9. The detection circuit connects a capacitor charged to a predetermined voltage to the composite capacitor to be measured, and flows a charging current through the composite capacitor to be measured. The pressure sensor according to claim 8.

10. The detection circuit connects an AC power supply to the composite capacitor to be measured and flows a charging current through the composite capacitor to be measured. The half-period of the AC voltage of the AC power supply is longer than the time constant of the circuit including the synthetic capacitor under measurement and the ionic material layer. The pressure sensor according to claim 8.

11. The region where the ionic material layer and the first electrode face each other is narrower than the region where the ionic material layer and the elastic body face each other. The pressure sensor according to claim 1.

12. The elastic body includes a plurality of individual elastic bodies corresponding to each of the plurality of composite capacitors, The plurality of individual elastic bodies are separated from each other, Each of the plurality of individual elastic bodies is provided with an individual second electrode. The pressure sensor according to claim 11.

13. The elastic body comprises a plurality of the aforementioned elastic bodies, The first electrode includes a plurality of first linear electrodes whose longitudinal direction is parallel to the first surface of the ionic material layer. The plurality of first linear electrodes are arranged on the first surface of the ionic material layer, spaced apart in a second direction parallel to the first surface and perpendicular to the first direction. The plurality of composite capacitors are arranged in a row along the first direction and the second direction, and the plurality of elastic bodies are arranged with gaps between them in the first direction. The pressure sensor according to claim 11.

14. The system further includes a detection circuit for detecting the capacitance of the second capacitor included in each of the plurality of composite capacitors, The aforementioned detection circuit is Of the aforementioned plurality of composite capacitors, no charging current is passed through one or more composite capacitors other than the composite capacitor to be measured, and a charging current is passed only through the composite capacitor to be measured. At the measurement timing after a charging current has been passed through the composite capacitor to be measured, the voltage value between the second electrode and the first electrode is measured. Based on the measurement result of the voltage value, the capacitance of the second capacitor included in the synthetic capacitor to be measured is detected. The range of the composite capacitor to be measured can be changed by changing the charging time during which the charging current is passed through the composite capacitor to be measured. The pressure sensor according to claim 11.

15. The detection circuit connects a capacitor charged to a predetermined voltage to the composite capacitor to be measured, and flows a charging current through the composite capacitor to be measured. The pressure sensor according to claim 14.

16. The detection circuit connects an AC power supply to the composite capacitor to be measured and flows a charging current through the composite capacitor to be measured. The half-period of the AC voltage of the AC power supply is longer than the time constant of the composite capacitor being measured. The pressure sensor according to claim 14.

17. The first electrode comprises multiple electrodes, The multiple first electrodes are arranged at intervals from each other on the outer edge of the ionic material layer. The pressure sensor according to claim 1.

18. It is further equipped with a detection circuit, The detection circuit determines the force application position based on the impedance between each of the plurality of first electrodes and the second electrode. The pressure sensor according to claim 17.

19. The aforementioned detection circuit is Of the plurality of first electrodes, the first electrode closest to the force application position is designated as the first electrode to be measured, and a charging current is passed between the first electrode to be measured and the second electrode. At a measurement timing after a charging current has been passed through the circuit, which includes the composite capacitor and the ionic material layer between the first and second electrodes of the object to be measured, for a charging time longer than the time constant of the circuit, the voltage value between the first and second electrodes of the object to be measured is measured. Based on the measurement result of the voltage value, the capacitance of the second capacitor included in the composite capacitor is detected. The pressure sensor according to claim 18.

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