Shear force detection device and temperature compensation method in shear force detection device

Abstract

To provide a compact shear force detection device capable of performing temperature compensation for pressing force respectively for a large number of shear force sensor cells.SOLUTION: Each temperature sensor cell 20 shares a first drive electrode 11 and a second drive electrode 12 with each shear force sensor cell 10 as first compensation electrodes. Each temperature sensor cell 20 includes the first drive electrode 11 being a first compensation electrode and a second compensation electrode 22 facing the second drive electrode 12, and a dielectric 25 that is arranged among the first drive electrode 11 and the second drive electrode 12 and the second compensation electrode 22, and has a material different from that of an insulating elastic body 40. Each temperature sensor cell further includes: multiple first wires for connecting a controller, the first drive electrodes 11, the second drive electrodes 12, first detection electrodes 16 and second detection electrodes 17 of the M shear force sensor cells 10; and multiple second wires for connecting the controller and the second compensation electrodes 22 of the N temperature sensor cells 20.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a shear force detection device that detects a shear force and a pressing force by using a change in capacitance, and a temperature compensation method in such a shear force detection device.

Background Art

[0002] Conventionally, as described in Patent Document 1 (Japanese Patent No. 6280579), a shear force detection device that detects a pressing force together with a shear force by using a change in capacitance has been known. The shear force detection device described in Patent Document 1 uses a foam of resin as an insulator for causing a change in capacitance due to stress by sandwiching the foam between electrodes.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A shear force detection device having a structure as described in Patent Document 1 is easily affected by the temperature during measurement because a dielectric such as a foam that generates capacitance changes depending on the ambient temperature. For example, when the temperature during measurement is changed from 0°C to 60°C in a shear force detection device such as that of Patent Document 1 without applying an external stress, a temperature-dependent error occurs in which a pressing force is detected even though no shear force is applied. It is conceivable to measure the temperature during overall measurement with a single thermometer and uniformly perform temperature compensation for a large number of shear force sensor cells arranged in a matrix for measuring, for example, shear forces and pressing forces at a plurality of locations. However, depending on the use of the shear force detection device, such uniform temperature compensation may be difficult. For example, in sitting pressure measurement, when sitting, the shear force sensor cells are warmed by body temperature, but since the temperature of the shear force sensor cells varies depending on the location, it is difficult to uniformly perform temperature compensation for all the shear force sensor cells.

[0005] An object of the present invention is to provide a compact shear force detection device capable of performing temperature compensation for pressing force for each of a large number of shear force sensor cells.

Means for Solving the Problem

[0006] Hereinafter, a plurality of aspects will be described as means for solving the problem. These aspects can be arbitrarily combined as necessary. The shear force detection device according to the first aspect of the present invention includes M (M is a natural number of 4 or more) shear force sensor cells, N (N is a natural number of 4 or more) temperature sensor cells, and a controller. The M shear force sensor cells are arranged side by side in a plane with respect to the pressure receiving surface, and detect the shear force applied to M locations on the pressure receiving surface and the pressing force in the direction perpendicular to the pressure receiving surface. The N temperature sensor cells are arranged between the M shear force sensor cells and the support surface so as to overlap the arrangement region of the M shear force sensor cells, and are used for temperature compensation of each of the M shear force sensor cells. The controller is connected to the M shear force sensor cells and the N temperature sensor cells, and detects the shear force by the M shear force sensor cells while performing temperature compensation of the pressing force by the N temperature sensor cells. Each of the M shear force sensor cells has a first drive electrode, a second drive electrode, a detection electrode, and an elastically deformable insulating elastic body. The first drive electrode and the second drive electrode are separated by a gap. The detection electrode overlaps the gap, the first drive electrode, and the second drive electrode, generating a first capacitance with the first drive electrode and a second capacitance with the second drive electrode. The insulating elastic body is disposed between the first drive electrode, the second drive electrode, and the detection electrode. The first drive electrodes and the second drive electrodes of the M shear force sensor cells are disposed on the first conductive layer, and the detection electrodes of the M shear force sensor cells are disposed on the second conductive layer facing the first conductive layer. Each of the N temperature sensor cells shares at least one of the first drive electrode and the second drive electrode or the detection electrode as a first compensation electrode with at least one of the M shear force sensor cells. Each of the N temperature sensor cells further has a second compensation electrode facing the first compensation electrode and a dielectric disposed between the first compensation electrode and the second compensation electrode, the dielectric being made of a material different from that of the insulating elastic body. The shear force detection device according to the first aspect further includes a plurality of first wirings and a plurality of second wirings. The plurality of first wirings are for connecting the controller to the first drive electrode, the second drive electrode, and the detection electrode of the M shear force sensor cells. The plurality of second wirings are for connecting the controller to the second compensation electrodes of the N temperature sensor cells. In the shear force detection device according to the first aspect, since the first compensation electrode is shared by the shear force sensor cell and the temperature sensor cell, the number of the second wirings can be significantly reduced, and a compact shear force detection device can be provided.

[0007] The shear force detection device according to the second aspect is the shear force detection device according to the first aspect, wherein the insulating elastic body is a foam, and the dielectric is a resin solid film. The shear force detection device according to the second aspect simplifies the processing in the controller in temperature measurement using the temperature sensor cell. The shear force detection device according to the third perspective is the shear force detection device according to the first or second perspective, in which the number of shear force sensor cells and temperature sensor cells is the same, and the shear force sensor cells and temperature sensor cells are associated with each other one by one. In the shear force detection device according to the third perspective, temperature compensation can be performed for each shear force sensor cell, and the accuracy can be improved for each shear force sensor cell. The shear force detection device according to the fourth perspective is the shear force detection device according to the first or second perspective, in which a plurality of shear force sensor cells are associated with one temperature sensor cell. In the shear force detection device according to the fourth perspective, the number of second wirings for the temperature sensor cell can be reduced, and the shear force detection device can be made more compact.

[0008] The temperature compensation method in the shear force detection device according to the fifth perspective is a temperature compensation method in a shear force detection device including M (M is a natural number of 4 or more) shear force sensor cells that detect a shear force applied to a pressure receiving surface and a pressing force perpendicular to the pressure receiving surface, N (N is a natural number of 4 or more) temperature sensor cells that are arranged overlapping the arrangement region of the shear force sensor cells and are used for temperature compensation of the shear force sensor cells, and a controller that is connected to the shear force sensor cells and the temperature sensor cells and performs temperature compensation of the pressing force by the temperature sensor cells while detecting the shear force and the pressing force by the shear force sensor cells. Each of the N temperature sensor cells shares at least one of the first drive electrode and the second drive electrode or the detection electrode of each of the M shear force sensor cells as the first compensation electrode with at least one of the M shear force sensor cells. Each of the N temperature sensor cells further has a second compensation electrode facing the first compensation electrode and a dielectric disposed between the first compensation electrode and the second compensation electrode. Each of the M shear force sensor cells further has an insulating elastic body disposed between the first drive electrode, the second drive electrode, and the detection electrode. The insulating elastic body and the dielectric have different materials from each other. In detecting the temperatures of N temperature sensor cells, the controller applies an alternating voltage to one of the first compensation electrode and the second compensation electrode and measures the charge at the other one. In the temperature compensation method according to the fifth aspect, since an alternating voltage can be applied to one of the first compensation electrode and the second compensation electrode and the charge can be measured at the other one in the same manner as the method for detecting the shearing force and the pressing force, the configuration of the shearing force detection device can be simplified.

[0009] In the temperature compensation method in the shearing force detection device according to the sixth aspect, in the temperature compensation method according to the fifth aspect, the insulating elastic body is a foam, the dielectric is a resin solid film, and during the detection of the pressing force of the shearing force sensor cell, the change in the capacitance of the temperature sensor cell due to the pressing force applied to the temperature sensor cell is regarded as zero to detect the temperature. In the temperature compensation method according to the sixth aspect, the processing in the controller in temperature measurement using the temperature sensor cell is simplified.

Advantages of the Invention

[0010] In the shearing force detection device and the temperature compensation method in the shearing force detection device according to the present invention, a compact shearing force detection device capable of performing temperature compensation of the pressing force for four or more shearing force sensor cells can be provided.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0012] (1) Overall Configuration FIG. 1 shows the concept of the configuration of the shear force detection device 1 according to the embodiment. Specifically, a large number of shear force sensor cells 10 as shown in FIG. 2 will be provided in the shear force detection device 1. However, in FIG. 1, only one of the large number of shear force sensor cells 10 is shown. In the example of FIG. 2, a plurality of shear force sensor cells 10 are arranged side by side in the X-axis direction, and a plurality of shear force sensor cells 10 are also arranged side by side in the Y-axis direction.

[0013] (1-1) Shear Force Sensor Cell 10 Each shear force sensor cell 10 has a first driving electrode 11, a second driving electrode 12, detection electrodes (first detection electrode 16 and second detection electrode 17), and a second compensation electrode 22. The first drive electrode 11 and the second drive electrode 12 each have a comb-shaped portion. By combining the comb-shaped portion of the first drive electrode 11 and the comb-shaped portion of the second drive electrode 12, a meandering gap 18 is formed. Four rectangular first detection electrodes 16 are superimposed on the gap 18 and the first drive electrode 11 and the second drive electrode 12 around the gap 18. The gap 18 is used to detect a shearing force in the X-axis direction. The first drive electrode 11 and the second drive electrode 12 each have a rectangular portion that extends rectangularly subordinate to the periphery. By combining the side of the first drive electrode 11 and the rectangular portion of the second drive electrode 12, a linear gap 19 is formed. A C-shaped second detection electrode 17 is superimposed on the gap 19 and the first drive electrode 11 and the second drive electrode 12 around the gap 19. The gap 19 is used to detect a shearing force in the Y-axis direction.

[0014] (1 - 2) Temperature sensor cell 20 and controller 3 Also, a second compensation electrode 22 is superimposed on the first drive electrode 11 and the second drive electrode 12. When detecting the temperature together with the second compensation electrode 22, the first drive electrode 11 and the second drive electrode 12 function as a first compensation electrode. The shearing force detection device 1 includes a controller 3 connected to M shearing force sensor cells and N temperature sensor cells in order to detect a shearing force and a pressing force at M points. Here, M is a natural number of 4 or more. Also, N is a natural number of 4 or more. The controller 3 performs temperature compensation of the pressing force by N temperature sensor cells 20 while detecting the shearing force by M shearing force sensor cells 10. The shearing force detection device 1 includes a plurality of first wirings 31 for connecting the controller 3 to the first drive electrode 11, the second drive electrode 12, and the detection electrodes (the first detection electrode 16, the second detection electrode 17) of M shearing force sensor cells 10. Also, the shearing force detection device 1 includes a second wiring 32 for connecting the controller 3 to the second compensation electrode 22 of N temperature sensor cells 20. For example, when the shear force sensor cells 10 are arranged in m1 columns in the X-axis direction and in m2 rows in the Y-axis direction, (m1 × m2) (= M) shear force sensor cells 10 are arranged. m1 is a natural number of 2 or more, and m2 is a natural number of 2 or more. For example, when m1 is 24 and m2 is 10, 240 shear force sensor cells 10 are arranged. To connect the m1 columns of shear force sensor cells 10 to the controller 3, (m1 × 2) first wirings 31 are required. Also, to connect the m2 rows of shear force sensor cells 10 to the controller 3, (m2 × 2) first wirings 31 are required. Further, for example, m2 second wirings 32 are required to connect the temperature sensor cells 20. In this case, m1 temperature sensor cells 20 are connected to the controller 3 by one second wiring 32.

[0015] FIG. 3 schematically shows a cross-sectional structure of the arrangement region AR1 of the shear force sensor cells 10. The plurality of shear force sensor cells 10 shown in FIG. 2 are arranged side by side in a plane with respect to the pressure receiving surface Sa1. In FIG. 2, the description of the temperature sensor cells 20 is omitted to prevent each member from being difficult to see. In the arrangement region AR1 of the shear force sensor cells 10, there are a pressure receiving surface Sa1 that receives a shear force and a pressing force, and a support surface Sa2 that abuts on a member that supports the shear force sensor cell 10. The pressure receiving surface Sa1 is one main surface of the fourth insulating layer La11, and the support surface Sa2 is one main surface of the first insulating layer La8, and these pressure receiving surface Sa1 and support surface Sa2 are exposed. Between the first insulating layer La8 and the fourth insulating layer La11, in order from the first insulating layer La8 toward the fourth insulating layer La11, a first shield layer La6, a second insulating layer La9, a third conductive layer La3, a dielectric layer La5, a first conductive layer La1, an insulating elastic body layer La4, a second conductive layer La2, a third insulating layer La10, and a second shield layer La7 are arranged. The first drive electrode 11 and the second drive electrode 12 are arranged on the first conductive layer La1. The first detection electrode 16 and the second detection electrode 17 are arranged on the second conductive layer La2. An elastically deformable insulating elastic body 40 is arranged between the first drive electrode 11 and the second drive electrode 12 and the first detection electrode 16 and the second detection electrode 17. In other words, the insulating elastic body 40 is arranged in the insulating elastic body layer La4 between the first conductive layer La1 and the second conductive layer La2. In the arrangement region AR1 of the shear force detection device 1, a second compensation electrode 22 facing the first drive electrode 11 and the second drive electrode 12 is provided. The second compensation electrode 22 is arranged on the third conductive layer La3. The temperature sensor cell 20 has a dielectric 25 between the first drive electrode 11 and the second drive electrode 12 and the second compensation electrode 22. The dielectric 25 is arranged in the dielectric layer La5 between the first conductive layer La1 and the third conductive layer La3. The first compensation electrode, the second compensation electrode 22, and the dielectric 25 constitute a temperature detection capacitor. The first shield layer La6 and the second shield layer La7 provided in the arrangement region AR1 of the M shear force sensor cells 10 are connected to, for example, the ground GND. By these first shield layer La6 and second shield layer La7, noise reduction is achieved in the shear force sensor cell 10. A first insulating layer La8 and a second insulating layer La9 for protecting the first shield layer La6 are provided, and a third insulating layer La10 and a fourth insulating layer La11 for protecting the second shield layer La7 are provided. The first insulating layer La8, the second insulating layer La9, the third insulating layer La10, and the fourth insulating layer La11 are layers made of insulators 41, 42, 43, 44. The second insulating layer La9 is arranged between the first shield layer La6 and the first conductive layer La1. The third insulating layer La10 is arranged between the second shield layer La7 and the second conductive layer La2.

[0016] (1 - 3) Detection of Shear Force and Pressing Force by the Controller 3 As shown in FIG. 1, the controller 3 includes a drive circuit 3a, a sense circuit 3b, and a temperature detection circuit 3c. When measuring the shear force, the drive circuit 3a applies an alternating voltage to the first drive electrode 11 and the second drive electrode 12 at different timings. The sense circuit 3b measures the capacitance based on the charges detected by the first detection electrode 16 and the second detection electrode 17 at the timings when a voltage is applied to the first drive electrode 11 and the second drive electrode 12, respectively, so that the controller 3 measures the capacitance. The measurement of the shear force by the controller 3 will be described with reference to the flowchart of FIG. 5. As shown in FIG. 6, the controller 3 measures the capacitances Cx1c, Cy1c, Cx2c, and Cy2c for calibration in a state where no shear force is applied. The arrows indicating the X-axis direction, Y-axis direction, and Z-axis direction shown in FIGS. 6 and 7 correspond to the left-right direction in FIG. 6 for the X-axis direction, the direction perpendicular to the paper surface of FIG. 6 for the Y-axis direction, and the left-right direction in FIG. 6 for the Y-axis direction and the direction perpendicular to the paper surface of FIG. 6 for the X-axis direction when explaining the first detection electrode 16 and the capacitances Cx1c and Cx2c, and when explaining the second detection electrode 17 and the capacitances Cy1c and Cy2c.

[0017] First, the drive circuit 3a of the controller 3 drives the first drive electrode 11 (step ST1). The sense circuit 3b of the controller 3 measures the charge generated between the first detection electrode 16 and the first drive electrode 11 due to the driving of the first drive electrode 11 (step ST2). At the same time, the sense circuit 3b measures the charge generated between the second detection electrode 17 and the first drive electrode 11 due to the driving of the first drive electrode 11 (step ST2). The controller 3 calculates the capacitances Cx1c and Cy1c used for calibration based on the measured charges (step ST3). Also, the drive circuit 3a drives the second drive electrode 12 (step ST4). The sense circuit 3b measures the charge generated between the first detection electrode 16 and the second drive electrode 12 due to the driving of the second drive electrode 12 (step ST5). At the same time, the sense circuit 3b measures the charge generated between the second detection electrode 17 and the second drive electrode 12 due to the driving of the second drive electrode 12 (step ST5). Based on the measured charge, the controller 3 calculates the capacitances Cx2c and Cy2c used for calibration (step ST6). Furthermore, the drive circuit 3a drives the first drive electrode 11 and the second drive electrode 12 (step ST7). The temperature detection circuit 3c measures the charge generated between the second compensation electrode 22 and the first drive electrode 11 and the second drive electrode 12 due to the driving of the first drive electrode 11 and the second drive electrode 12 (step ST8). Based on the measured charge, the controller 3 calculates the temperature T0 of the shear force sensor cell 10 used for calibration (step ST9).

[0018] FIG. 7 shows, for example, the capacitances Cx1, Cy1, Cx2, and Cy2 when a human 100 is sitting on the seat surface 201. The controller 3 measures the capacitances Cx1, Cy1, Cx2, and Cy2 in a state where a shear force is applied, for example, when a human 100 sits on the seat surface 201. For example, when a human 100 sits on the seat surface 201, the positional relationship between the first detection electrode 16 and the first drive electrode 11 and the second drive electrode 12 may change. Similarly, when a human 100 sits on the seat surface 201, the positional relationship between the second detection electrode 17 and the first drive electrode 11 and the second drive electrode 12 may change. If the first detection electrode 16 moves in the Z direction and the distances between the first detection electrode 16 and the first drive electrode 11 and the second drive electrode 12 are reduced, both the capacitances Cx1 and Cx2 increase. If the first detection electrode 16 moves in the X-axis direction and, in a plan view (viewed in the Z-axis direction), compared to the state of FIG. 6, for example, the overlapping area between the first detection electrode 16 and the first drive electrode 11 increases and the overlapping area between the first detection electrode 16 and the second drive electrode 12 decreases, the capacitance Cx1 increases and the capacitance Cx2 decreases. If the second detection electrode 17 moves in the Y-axis direction and, in a plan view (viewed in the Z-axis direction), compared to the state of FIG. 6, for example, the overlapping area between the second detection electrode 17 and the first drive electrode 11 increases and the overlapping area between the second detection electrode 17 and the second drive electrode 12 decreases, the capacitance Cy1 increases and the capacitance Cy2 decreases. The drive circuit 3a of the controller 3 drives the first drive electrode 11 (step ST10). The sense circuit 3b measures the charge generated between the displaced first detection electrode 16 and the first drive electrode 11 due to the driving of the first drive electrode 11 (step ST11). At the same time, the sense circuit 3b measures the charge generated between the displaced second detection electrode 17 and the first drive electrode 11 due to the driving of the first drive electrode 11 (step ST11). Based on the measured charges, the controller 3 calculates the capacitances Cx1 and Cy1 that have changed due to the human 100 sitting down (step ST12). Also, the drive circuit 3a drives the second drive electrode 12 (step ST13). The sense circuit 3b measures the charge generated between the displaced first detection electrode 16 and the second drive electrode 12 due to the driving of the second drive electrode 12 (step ST14). At the same time, the sense circuit 3b measures the charge generated between the displaced second detection electrode 17 and the second drive electrode 12 due to the driving of the second drive electrode 12 (step ST14). Based on the measured charges, the controller 3 calculates the capacitances Cx2 and Cy2 that have changed due to the human 100 sitting down (step ST15). Furthermore, the drive circuit 3a drives the first drive electrode 11 and the second drive electrode 12 (step ST16). The temperature detection circuit 3c measures the charge generated between the second compensation electrode 22 and the first drive electrode 11 and the second drive electrode 12 due to the driving of the first drive electrode 11 and the second drive electrode 12 (step ST17). Based on the measured charges, the controller 3 calculates the temperature T1 of the shear force sensor cell 10 used for temperature compensation when the human 100 sits down (step ST18).

[0019] The controller 3 calculates the shear forces Fx and Fy and the pressing force PFz from the measured capacitances Cx1c, Cy1c, Cx2c, Cy2c, Cx1, Cy1, Cx2, and Cy2 (step ST19). Regarding the measurement of the shear forces Fx and Fy, since they are less affected by temperature, this controller 3 does not perform temperature compensation. Therefore, the controller 3 calculates the shearing force Fx in the X-axis direction according to the following formula (1). Here, Kx is a constant. Fx = Kx · {Cx1 / (Cx1 + Cx2) - Cx1c / (Cx1c + Cx2c)} ···(1) The controller 3 calculates the shearing force Fy in the Y-axis direction according to the following formula (2). Here, Ky is a constant. Fy = Ky · {Cy1 / (Cy1 + Cy2) - Cy1c / (Cy1c + Cy2c)} ···(2) The controller 3 calculates the pressing force PFz before temperature compensation in the Z-axis direction according to the following formula (3). Here, PKz is a constant. PFz = PKz · {(Cx1 + Cx2 + Cy1 + Cy2) / (Cx1c + Cx2c + Cy1c + Cy2c) - 1} ···(3) Here, for the sake of easy understanding, the case where the shearing forces Fx and Fy and the pressing force PFz are proportional to the change in capacitance is described. However, even if the shearing forces Fx and Fy and the pressing force PFz are not proportional to the change in capacitance, as long as they can be obtained from the change in capacitance, the present invention can be applied to perform temperature compensation.

[0020] First, the temperature compensation of capacitance is described. The capacitances of the capacitors composed of the detection electrodes and the drive electrodes, such as Cx1, Cx2, Cy1, Cy2, Cx1c, Cx2c, Cy1c, and Cy2c, can generally be expressed as functions depending on the magnitude F of the pressing force PFz in the vertical direction (Z-axis direction) and the temperature T. Here, for the capacitance of the capacitor composed of the detection electrode and the drive electrode, the function depending on the magnitude F of the pressing force PFz in the vertical direction (Z-axis direction) and the temperature T is represented as Γ1(F, T). Assuming that the function of the above-described capacitance depending on the pressing force PFz is α1(F) and the function of the above-described capacitance depending on the temperature T is β1(T), the following formula (4) holds. Note that the value of Γ1(F, T) corresponds to the actually measured value of the capacitance in the state of the magnitude F of the pressing force PFz and the temperature T. Γ1(F, T) = Γ1b + α1(F) + β1(T) ···(4) However, for example, when the temperature is 20°C, taking the state where the pressing force PFz is not applied (PFz = 0) as the baseline, let α1(0)=0 and β1(20)=0. That is, it is defined that Γ1(0,20) measured at the baseline is Γ1b, and this Γ1b is a constant. Also, the capacitance of the capacitor formed by the second compensation electrode 22, the first drive electrode 11, and the second drive electrode 12 can generally be expressed as a function depending on the magnitude F of the pressing force PFz in the vertical direction (Z direction) and the temperature T, similar to Equation (1). Here, the first drive electrode 11 and the second drive electrode 12 can be regarded as the first compensation electrode. Here, for the capacitance of the capacitor formed by the first compensation electrode and the second compensation electrode 22, the function depending on the magnitude F of the pressing force PFz in the vertical direction (Z direction) and the temperature T is represented as Γ2(F,T). Let the function of the aforementioned capacitance depending on the pressing force PFz be α2(F), and the function of the aforementioned capacitance depending on the temperature T be β2(T), then the following Equation (6) holds. Γ2(F,T)=Γ2b+α2(F)+β2(T) ···(6) However, for example, when the temperature is 20°C, taking the state where the pressing force PFz is not applied (PFz = 0) as the baseline, let α2(0)=0 and β2(20)=0. That is, it is defined that Γ2(0,20) measured at the baseline is Γ2b, and this Γ2b is a constant. For example, if the environmental temperature T0 is 25°C, in step ST8 performed during calibration, the environmental temperature is calculated as in Equation (7) from the measured capacitance (step ST9). Γ2(0,25)-Γ2b-α2(0)=β2(T) ···(7) Here, Γ2(0,25) is a measured value or a value directly obtained from the measured value. When the pressing force PFz is 0, since α2(0)=0, the value of (Γ2(0,25)-Γ2b) can be calculated, and the value of β2 can be calculated. By calculating the value of β2(25), T can be derived from the function β2, so T = 25°C is calculated from the function β2. Using this T = 25°C, Equation (8) is obtained from Equation (4). Γ1(0, 25) = Γ1b + α1(0) + β1(25) ···(8) Here, since α1(0) = 0, from Equation (7), the value of β1(25) (Γ1(0, 25) - Γ1b) can be calculated.

[0021] For example, assume that due to a human 100 sitting on the seat surface 201 in FIG. 4 for measurement, the temperature of the portion of the seat surface 201 in contact with the buttocks of the human 100 has risen to 35°C. Also, let the pressing force in the Z-axis direction by which the seat surface 201 is pressed by the buttocks of the human 100 be PFa. In this case, Equation (6) is expressed as the following Equation (9) using the temperature of 35°C at the portion where the buttocks of the human 100 are in contact and the pressing force PFa. Γ2(PFa, 35) = Γ2b + α2(PFa) + β2(35) ···(9) Here, to simplify the calculation, assuming that the dielectric 25 of the dielectric layer La5 does not deform under the pressing force PFa, since α2(0) = 0, α2(PFa) = 0. Since Γ2(PFa, 35) is a measured value or a value directly obtained from the measured value, the value of {Γ2(PFa, 35) - Γ2b} can be obtained, so the value of β2 can be calculated. By calculating the value of β2, T is derived from the function β2. In this case, T = 35°C is calculated from the function β2. Substituting T = 35°C into Equation (4), the following Equation (10) is obtained. Γ1(PFa, 35) = Γ1b + α1(PFa) + β1(35) ···(10) By transforming Equation (10), Equation (11) is obtained. α1(PFa) = Γ1(PFa, 35) - Γ1b - β1(35) ···(11) In Equation (11), Γ1(PFa, 35) is a measured value or a value directly obtained from the measured value, and Γ1b is a constant. Also, β1(35) is also a value that can be determined if the function β(T) is obtained in advance by, for example, experiments or simulations and the temperature is measured by the temperature sensor cell 20. Therefore, it can be understood that the capacitance α1(PFa) that changes due to the pressing force PFa excluding the influence of temperature can be detected by the shear force detection device 1 through measurement along the flow shown in FIG. 5.

[0022] So far, the relationship between capacitance and temperature has been described. Next, the relationship between the pressing force PFz and temperature will be described. FIG. 8 shows an example of detection results when the temperature of the shear force sensor cell 10 is changed without applying the pressing force PFz (PFz = 0) and without temperature compensation for the pressing force PFz. When the shear force sensor cell 10 is at 20°C, since no pressing force PFz is applied, the shear force detection device 1 correctly detects 0 kPa. However, as the temperature of the shear force sensor cell 10 rises to 30°C, 40°C, 50°C, and 60°C, the shear force detection device 1 outputs detection results such that the force in the direction opposite to pushing the shear force sensor cell 10 (i.e., the pulling direction) increases. In the example shown in FIG. 8, it can be seen that if temperature compensation is performed assuming that the error in the detection results output by the shear force detection device 1 increases proportionally to the temperature, the error in the detection results of the pressing force PFz can be suppressed. Considering the pressing force PFz assuming that the same magnitude of the pressing force PFz is applied during calibration (temperature is 25°C) and during measurement (temperature is 35°C), Equation (12) is derived from Equation (3). In Equation (12), the subscript "m" indicates the value at 25°C, and the subscript "n" indicates the value at 35°C. However, since Cx1c, Cx2c, Cy1c, and Cy2c are defined as the capacitances during calibration, the subscript "m" is omitted. PFzn - PFzm = PKz·{(Cx1n + Cx2n + Cy1n + Cy2n) / (Cx1c + Cx2c + Cy1c + Cy2c) - 1} - PKz·{(Cx1m + Cx2m + Cy1m + Cy2m) / (Cx1c + Cx2c + Cy1c + Cy2c) - 1} ···(12) When Equation (12) is rearranged, it becomes Equation (13). PFzn - PFzm = PKz·〔(Cx1n + Cx2n + Cy1n + Cy2n) - (Cx1m + Cx2m + Cy1m + Cy2m)〕 / (Cx1c + Cx2c + Cy1c + Cy2c) ···(13) From Equation (13), it can be seen that the difference (PFzn - PFzm) in the pressing force PFz output by the shear force detection device 1 between calibration and actual measurement is proportional to the difference in capacitance [(Cx1n + Cx2n + Cy1n + Cy2n) - (Cx1m + Cx2m + Cy1m + Cy2m)].

[0023] When simultaneously changing the pressing force PFz and the temperature T from the calibrated state, for example, when the pressing force is PFa and the temperature is 35°C, whether first changing only the pressing force PFz from the calibrated state to PFa and then changing only the temperature from the calibrated state to 35°C, or vice versa, the output result of the shear force detection device 1 will be the same. Therefore, using Equation (4) to calculate the difference in capacitance between 25°C and 35°C when the same pressing force PFa is applied, it becomes as shown in Equations (14) and (15). Γ1(PFa, 25) = Γ1b + α1(PFa) + β1(25) ···(14) Γ1(PFa, 35) = Γ1b + α1(PFa) + β1(35) ···(15) Subtracting the two sides of Equations (14) and (15) gives Equation (16). Γ1(PFa, 35) - Γ1(PFa, 25) = β1(35) - β1(25) ···(16) The left side of Equation (16), {Γ1(PFa, 35) - Γ1(PFa, 25)}, represents the change in capacitance detected when the temperature changes from 25°C to 35°C with the pressing force PFa applied. For example, when the pressing force PFz draws a characteristic curve (straight line) as shown in Figure 8 according to the temperature, the difference between PFzm at the time of calibration and PFzn in the state at 35°C is proportional to the difference in capacitance {β1(35) - β1(25)} on the right side of Equation (16). Therefore, if the proportionality constant PKz is specified in advance through experiments, PFzn in the state at 35°C can be compensated as shown in Equation (17). PFzn = PFzm - PKz·{β1(35) - β1(25)} ···(17) In Equation (17), PFm is obtained from Cx1c, Cx2c, Cy1c, and Cy2c calculated in Step ST3 and Step ST6. The temperature of 25°C during the calibration of the shear force sensor cell 10 and the temperature of 35°C when a person sits are calculated in Steps ST9 and ST18 by the temperature sensor cell 20. The function β1(T) can be determined in advance by, for example, experiments or simulations and stored in the controller 3.

[0024] (2) Detailed Configuration (2-1) Insulating Elastic Body Layer La4 For the material of the insulating elastic body layer La4, in order to detect the pressing force PFz, it is preferable to use a material with a large compressive deformation. Examples of materials with a large compressive deformation used for the insulating elastic body layer La4 of the shear force detection device 1 of the second embodiment include foams and gels. Examples of foams include those in which gas is finely dispersed in a resin and formed into a foamed or porous shape. Examples of the material of the foam include silicone, urethane, polyethylene, and polystyrene. The thickness of the insulating elastic body layer La4 of the second embodiment is appropriately selected from, for example, the range of 2 μm to 5 mm. Conductive particles may be added to the insulating elastic body layer La4 at a ratio within the range that can maintain insulation. Examples of the material of the conductive particles include carbon black, gold, silver, and nickel. When pressed, the distance between the contained conductive particles approaches, and the value of the capacitance between the first conductive layer La1 and the second conductive layer La2 rises rapidly, thereby having the effect of improving sensitivity. The average particle diameter of the conductive particles is preferably 1 / 10 or less of the thickness of the insulating elastic body layer La4. (2-2) First Conductive Layer La1, Second Conductive Layer La2, and Third Conductive Layer La3, and First Shielding Layer La6 and Second Shielding Layer La7 The first conductive layer La1, the second conductive layer La2, the third conductive layer La3, the first shield layer La6, and the second shield layer La7 are made of thin films having conductivity. Examples of the materials for the first conductive layer La1, the second conductive layer La2, the third conductive layer La3, the first shield layer La6, and the second shield layer La7 include metal films, conductive ceramic films, conductive paste films, and conductive polymer films. Examples of the metal film include films of gold, silver, copper, nickel, aluminum, titanium, and palladium. Examples of the conductive ceramic film include films of indium tin oxide and zinc oxide. Examples of the conductive paste film include those obtained by forming a material in which metal particles are dispersed in a resin binder into a thin film. Examples of the material for the conductive paste film include silver paste. Examples of the conductive polymer film include films of polyhexylthiophene, poly(dioctylfluorene), pentacene, and tetrabenzoporphyrin. To form the first driving electrode 11 and the second driving electrode 12 on the first conductive layer La1, the first detection electrode 16 and the second detection electrode 17 on the second conductive layer La2, and the second compensation electrode 22 on the third conductive layer La3, for example, there is a method of forming a conductive film over the entire layer and then patterning it by etching. To form the conductive film over the entire layer, for example, lamination of a rolled conductive film, plating, sputtering, vapor deposition, or ion plating can be used. Also, in the case of a conductive paste film, a method of directly forming a pattern by a printing method such as screen printing, gravure printing, or offset printing can be used. The thicknesses of the first conductive layer La1, the second conductive layer La2, and the third conductive layer La3 are appropriately selected from, for example, the range of 0.1 μm to 5 mm. The shapes of the first driving electrode 11, the second driving electrode 12, the first detection electrode 16, the second detection electrode 17, and the second compensation electrode 22 are not limited to, for example, the shapes shown in FIGS. 1 and 2. Also, these shapes do not have to be repetitions of the same pattern. Also, the gaps 18, 19, the first detection electrode 16, and the second detection electrode 17 do not necessarily need to be arranged so as to extend in the Y-axis direction and the X-axis direction. For example, the first detection electrode 16 and the second detection electrode 17 may be arranged so as to extend at an angle of 45 degrees with respect to the X-axis direction and the Y-axis direction. Furthermore, the first detection electrode 16 and the second detection electrode 17 do not necessarily need to be regularly arranged, and may be arranged randomly, for example. Furthermore, the second compensation electrode 22 does not necessarily need to face both the first driving electrode 11 and the second driving electrode 12, and may be configured to face only one of the first driving electrode or the second driving electrode 12, for example. The first shield layer La6 and the second shield layer La7 are formed by providing a conductive film over the entire layer. To form the conductive film over the entire layer, for example, the method used to form the first conductive layer La1, the second conductive layer La2, and the third conductive layer La3 can be applied. (2-3) The first insulating layer La8 to the fourth insulating layer La11 Examples of the materials of the insulators 41, 42, 43, 44 that constitute the first insulating layer La8 to the fourth insulating layer La11 include a thermoplastic resin sheet, a thermosetting resin sheet, or an ultraviolet curable resin sheet. Examples of the materials of the thermoplastic resin sheet and the thermosetting resin sheet include polyethylene terephthalate (PET) resin, silicone resin, acrylic resin, urethane resin, fluororesin, polyester resin, polycarbonate resin, polyacetal resin, polyamide resin, and olefin. Examples of the materials of the ultraviolet curable resin sheet include acrylic-based resins, epoxy-based resins, and silicone-based resins.

[0025] (2-4) The first wiring 31 and the second wiring 32 The first wiring 31 connected to the first drive electrode 11, the second drive electrode 12, the first detection electrode 16, and the second detection electrode 17 is disposed, for example, in the first conductive layer La1 and the second conductive layer La2. Also, the second wiring 32 connected to the second compensation electrode 22 is disposed, for example, in the third conductive layer La3. The first wiring 31 and the second wiring 32 may be disposed outside the first conductive layer La1 to the third conductive layer La3. However, in order to make the shear force detection device 1 compact, it is preferable that the first wiring 31 is disposed in the first conductive layer La1 and the second conductive layer La2 where the first drive electrode 11, the second drive electrode 12, the first detection electrode 16, and the second detection electrode 17 are disposed. For the same reason, it is preferable that the second wiring 32 is disposed in the third conductive layer La3 where the second compensation electrode 22 is disposed. However, since the first wiring 31 and the second wiring 32 are affected by the deformation of the insulating elastic body layer La4, there is a risk of disconnection and poor connection. Therefore, in order to reduce the risk of failure, it is preferable that the number of the first wiring 31 and the second wiring 32 is small. (2-5) Dielectric layer La5 The dielectric layer La5 is composed of a dielectric 25 which is a material different from the insulating elastic body 40 constituting the insulating elastic body layer La4. The dielectric layer La5 forms a temperature detection capacitor for detecting temperature. The electrodes of this temperature detection capacitor are the first drive electrode 11 and the second drive electrode 12, and the second compensation electrode 22 facing them. Since the insulating elastic body 40 and the dielectric 25 are formed of different materials, at least one of the temperature characteristics of the dielectric constant, the thermal expansion coefficient, the Poisson's ratio, and the Young's modulus is different. Therefore, the temperature can be detected using the temperature sensor cell 20. Here, consider the detection of temperature when the insulating elastic body 40 and the dielectric 25 are made of different materials. Let the capacitance of the stress detection capacitor for detecting the pressing force F be Γ1, the coefficient for converting the change in the pressing force F into the change per unit capacitance of the capacitance Γ1 be U1, and the coefficient for converting the change in temperature T into the change per unit capacitance of the capacitance Γ1 be V1. Then, the following equation (18) holds. Also, let the capacitance of the temperature detection capacitor be Γ2, the coefficient for converting the change ΔF in the pressing force PFz into the change per unit capacitance of the capacitance Γ2 be U2, and the coefficient for converting the change ΔT in temperature T into the change per unit capacitance of the capacitance Γ2 be V2. Then, the following equation (19) holds. However, for simplicity of explanation, in the measurement range of the shear force detection device 1, assume that these can be regarded as linear functions. ΔΓ1 / Γ1 = U1·ΔF + V1·ΔT ···(18) ΔΓ2 / Γ2 = U2·ΔF + V2·ΔT ···(19)

[0026] When the environmental temperature is kept constant and the pressing force F is changed, the slopes U1 and U2 can be obtained. Also, when the pressing force is kept constant or zero and the environmental temperature T is changed, the slopes V1 and V2 can be obtained. The slope V1 is, for example, the slope of the graph in FIG. 8. Furthermore, since ΔΓ1 / Γ1 and ΔΓ2 / Γ2 are obtained from the measurement results, by solving the simultaneous equations of the above equations (18) and (19) for the unknown variables ΔF and ΔT, the following equations (20) and (21) can be obtained. ΔF = (V2·ΔΓ1 / Γ1 - V1·ΔΓ2 / Γ2) / (U1·V2 - U2·V1) ···(20) ΔT = (U2·ΔΓ1 / Γ1 - U1·ΔΓ2 / Γ2) / (U1·V2 - U2·V1) ···(21) If the materials of the insulating elastic body 40 and the dielectric 25 are the same, then U1 = U2 and V1 = V2. As a result, the denominators of equations (20) and (21) become zero, and thus the solution of the simultaneous equations (18) and (19) described above cannot be obtained. In other words, if the materials of the insulating elastic body 40 and the dielectric 25 are the same, the temperature compensation of the shear force detection device 1 cannot be achieved. Note that even if the insulating elastic body 40 and the dielectric 25 are made of different materials, it is theoretically possible that U1·V2 = U2·V1. However, in reality, such a situation does not occur. Therefore, if the insulating elastic body 40 and the dielectric 25 are made of different materials, the pressing force PFz can be detected while performing temperature compensation. For example, when the dielectric 25 is such that U2 is sufficiently smaller than U1 and (U2 / U1) can be regarded as 0 (approximated), equation (21) can be further transformed as follows after being transformed into ΔT = ((U2 / U1)·ΔΓ1 / Γ1 - ΔΓ2 / Γ2) / (V2 - (U2 / U1)·V1). ΔT ≒ (ΔΓ2 / Γ2) / V2 ···(22) For example, when the insulating elastic body 40 is a foam and the dielectric 25 is a resin solid film, even if stress is applied to the temperature detection capacitor, it is possible to detect the compensation temperature change ΔT using only the temperature detection capacitor as in equation (22). Therefore, it is preferable to use a resin solid film for the dielectric 25. Examples of the material of the resin solid film include a thermoplastic resin sheet, a thermosetting resin sheet, or an ultraviolet curable resin sheet. Examples of the materials of the thermoplastic resin sheet and the thermosetting resin sheet include polyethylene terephthalate (PET) resin, silicone resin, acrylic resin, urethane resin, fluororesin, polyester resin, polycarbonate resin, polyacetal resin, polyamide resin, and olefin. Examples of the materials of the ultraviolet curable resin sheet include acrylic resin, epoxy resin, and silicone resin.

[0027] (3) Modified Example (3-1) Modified Example A In the above-described embodiment, the case where the first drive electrodes 11 and 12 are used as the first compensation electrodes has been described. However, as shown in FIG. 9, at least one of the first detection electrode 16 and the second detection electrode 17 can also be used as the first compensation electrode. In the case of the configuration as shown in FIG. 9, the controller 3 applies, for example, an alternating voltage by the second compensation electrode 22, and measures the charge by at least one of the first detection electrode 16 and the second detection electrode 17 to calculate the capacitance of the temperature detection capacitor. The controller 3 calculates the ambient temperature from the capacitance of this temperature detection capacitor. (3-2) Modified Example B In the above-described embodiment, the case where the first drive electrodes 11 and 12 are driven respectively when detecting the shear force and the pressing force and when detecting the temperature has been described. However, when the first drive electrodes 11 and 12 are driven, the shear force and the pressing force and the temperature may be detected simultaneously. (3-3) Modified Example C In the above-described embodiment, the case where the number of the shear force sensor cells 10 and the temperature sensor cells 20 is the same and the shear force sensor cells 10 and the temperature sensor cells 20 are associated one-to-one has been described. However, N does not have to be the same as M. A plurality of shear force sensor cells 10 may be associated with one temperature sensor cell 20. For example, as shown in FIG. 10, one temperature sensor cell 20 may be provided for four shear force sensor cells 10. In that case, for example, four sets of the first detection electrodes 16 and the second detection electrodes 17 are used as one first compensation electrode and shared by 60 sets of the shear force sensor cells 10. In this case, the number of the shear force sensor cells 10 is 240, while the number of the temperature sensor cells 20 is 60. Also, the number of the shear force sensor cells 10 associated with one temperature sensor cell 20 does not have to be constant, and the number of the shear force sensor cells 10 associated with one temperature sensor cell 20 may be varied variously. (3-4) Modified Example D In the above-described embodiments and modified examples, the case where there are the first detection electrode 16 and the second detection electrode 17 as detection electrodes has been described. However, as the detection electrode, it can be configured to have one type of detection electrode, or it can also be configured to have three or more types of detection electrodes (the first detection electrode, the second detection electrode, the third detection electrode, ···).

[0028] (4) Features (4-1) In the shear force detection device 1 of the above-described embodiment or modified example, for example, 240 (=M) shear force sensor cells 10 are arranged side by side on the pressure receiving surface Sa1. M = 240 is an example, and the number M of the shear force sensor cells 10 is a natural number of 4 or more. These shear force sensor cells 10 detect the shear force applied to 240 locations on the pressure receiving surface Sa1 and the pressing force in the direction perpendicular to the pressure receiving surface Sa1. In the above-described embodiment or modified example, for example, 240 (=N) temperature sensor cells 20 are arranged between the shear force sensor cells 10 and the support surface Sa2 so as to overlap the arrangement region AR1 of the 240 shear force sensor cells 10. For example, the controller 3 is connected to the 240 shear force sensor cells 10 and the 240 temperature sensor cells 20. In the above example, each of the 240 shear force sensor cells 10 includes the first drive electrode 11 and the second drive electrode 12, the first detection electrode 16 and the second detection electrode 17 which are detection electrodes, and the insulating elastic body 40. The first drive electrode 11 and the second drive electrode 12 are arranged in the first conductive layer La1 and are separated by the gaps 18, 19. The first detection electrode 16 and the second detection electrode 17 are arranged in the second conductive layer La2 and are overlapped with the gaps 18, 19, the first drive electrode 11, and the second drive electrode 12. The first detection electrode 16 generates an electrostatic capacitance Cx1 which is the first capacitance between the first drive electrode 11. The second detection electrode 17 generates an electrostatic capacitance Cy1 which is the first capacitance between the first drive electrode 11. The first detection electrode 16 generates an electrostatic capacitance Cx2 which is the second capacitance between the second drive electrode 12. Also, the second detection electrode 17 generates an electrostatic capacitance Cy2 which is the second capacitance between the second drive electrode 12. The insulating elastic body 40 is disposed between the first drive electrodes 11 and 12 and the first detection electrodes 16 and 17 and the second detection electrodes 17. For example, in each of the 240 temperature sensor cells 20, in the above-described embodiment or modification, the first drive electrodes 11 and 12 are shared with the 240 shear force sensor cells 10 as the first compensation electrodes. However, only the first drive electrode 11 may be shared with the 240 shear force sensor cells 10 as the first compensation electrode, or only the second drive electrode 12 may be shared with the 240 shear force sensor cells 10 as the first compensation electrode. For example, in each of the 240 temperature sensor cells 20, as described in Modification A, the first detection electrodes 16 and 17 may be shared with the 240 shear force sensor cells 10 as the first compensation electrodes. Also, only the first detection electrode 16 may be shared with the 240 shear force sensor cells 10 as the first compensation electrode, or only the second detection electrode 17 may be shared with the 240 shear force sensor cells 10 as the first compensation electrode. Furthermore, as described in Modification C, N may not be the same as M. In the above-described embodiment or modification, in the shear force detection device 1, for example, each of the 240 temperature sensor cells 20 includes a second compensation electrode 22 facing the first compensation electrode, and a dielectric 25 disposed between the first compensation electrode and the second compensation electrode 22. The dielectric 25 is made of a material different from that of the insulating elastic body 40. Since the materials of the dielectric 25 and the insulating elastic body 40 are different, the shear force detection device 1 can detect the temperature by the shear force sensor cells 10 and the temperature sensor cells 20 even when a stress is applied to the pressure receiving surface Sa1. The controller 3 is connected to the first drive electrodes 11, the second drive electrodes 12, and the detection electrodes (the first detection electrodes 16 and the second detection electrodes 17) of the 240 shear force sensor cells 10 by, for example, 68 first wirings 31 (24 columns × 2 + 10 rows × 2). The controller 3 is connected to the second compensation electrodes 22 of the 240 temperature sensor cells 20 by, for example, 10 second wirings 32. In the above-described embodiment or modification, since the first compensation electrode is shared by the shear force sensor cell 10 and the temperature sensor cell 20, the number of the second wirings 32 can be significantly reduced (for example, 24 or 10 can be reduced), and the compact shear force detection device 1 can be provided.

[0029] (4-2) The shear force detection device 1 can be configured such that the insulating elastic body 40 is a foam made of a foamed material and the dielectric 25 is a resin solid film. As described with reference to formula (14), in the shear force detection device 1 configured in this way, the processing in the controller 3 in temperature measurement using the temperature sensor cell 20 is simplified. (4-3) The shear force detection device 1 may be configured such that the number M of the shear force sensor cells 10 is the same as the number N of the temperature sensor cells 20 (M = N), and the shear force sensor cells 10 and the temperature sensor cells 20 are associated with each other one-to-one. In the shear force detection device 1 configured in this way, temperature compensation can be performed for each of the shear force sensor cells 10, and the accuracy can be improved for each of the shear force sensor cells 10. FIG. 11 shows a seat 200 on which the shear force detection device 1 is placed on the seat surface 201. For example, when a human 100 sits on the seat surface 201 of the seat 200 (see FIG. 4), the detection results of the shear force by the shear force sensor cells 10 arranged in a matrix of 10 rows and 24 columns are shown. The arrow indicates the vector of the shear force, the direction of the arrow represents the direction of the shear force, and the length of the arrow represents the magnitude of the shear force. Further, the region surrounded by the square indicates the portion where the temperature is increased by the body temperature of the human 100, and the denser the dots are, the higher the temperature is. From FIG. 11, it can be seen that by configuring the shear force sensor cells 10 and the temperature sensor cells 20 to be associated with each other one-to-one, even when the portion heated by the body temperature of the human 100 is limited to a relatively narrow range and the portion where the temperature changes is narrow, the accuracy can be improved for each of the shear force sensor cells 10.

[0030] (4-4) A plurality of shear force sensor cells 10 may be configured to be associated with one temperature sensor cell 20. In the shear force detection device 1 configured in this way, the number of second wirings 32 for the temperature sensor cell 20 can be further reduced. By reducing the number of second wirings 32, the shear force detection device 1 can be further miniaturized. (4-5) In the shear force detection device 1 of the above embodiment or modification, for example, each of 240 temperature sensor cells 20 (= N) shares at least one of the first drive electrodes 11 and the second drive electrodes 12 of each of 240 shear force sensor cells 10 (= M) or the first detection electrodes 16 and the second detection electrodes 17 which are detection electrodes, as 240 first compensation electrodes for the shear force sensor cells 10. Each temperature sensor cell 20 further has a second compensation electrode 22 facing the first compensation electrode, and a dielectric 25 made of a material different from that of the insulating elastic body 40 disposed between the first compensation electrode and the second compensation electrode 22 and disposed between the first drive electrodes 11 and the second drive electrodes 12 and the first detection electrodes 16 and the second detection electrodes 17. In the temperature compensation method in such a shear force detection device 1, the controller 3 applies an alternating voltage to one of the first compensation electrode and the second compensation electrode 22 and measures the charge at the other when detecting the temperatures of, for example, 240 temperature sensor cells 20. Therefore, in the temperature compensation method of the shear force detection device 1 configured in this way, an alternating voltage can be applied to one of the first compensation electrode and the second compensation electrode 22 and the charge can be measured in the same way as the detection method of the shear force and the pressing force, so that the configuration of the shear force detection device 1 can be simplified. (4-6) In the temperature compensation method of the shear force detection device 1 according to the above embodiment or modification, when the shear force sensor cell 10 includes a stress detection capacitor having an insulating elastic body 40 that is a foam, and the temperature sensor cell 20 includes a temperature detection capacitor having a resin solid film as the dielectric 25, the method described by Equation (14) can be used. In the method described using Equation (14), during the detection of the pressing force PFz of the shear force sensor cell 10, the temperature is detected by regarding the change in the capacitance of the temperature sensor cell 20 due to the pressing force applied to the temperature sensor cell 20 as zero. In such a temperature compensation method, as described using Equation (14), the processing in the controller 3 in the temperature measurement using the temperature sensor cell 20 is simplified. As described above, one embodiment or a modification thereof of the present invention has been described. However, the present invention is not limited to the above embodiment or its modification, and various changes are possible without departing from the gist of the invention. In particular, the plurality of embodiments and modifications described in this specification can be arbitrarily combined as needed.

Explanation of Signs

[0031] 1 Shear force detection device 3 Controller 10 Shear force sensor cell 11 First drive electrode 12 Second drive electrode 16 First detection electrode 17 Second detection electrode 18, 19 Gap 20 Temperature sensor cell 22 Second compensation electrode 25 Dielectric 31 First wiring 32 Second wiring 40 Insulating elastic body AR1 Arrangement area La1 First conductive layer La2 Second conductive layer La3 Third conductive layer La4 Insulating elastic body layer La5 Dielectric layer

Claims

1. M shear force sensor cells are arranged in a plane on the pressure receiving surface and detect shear forces acting on M points on the pressure receiving surface (M is a natural number of 4 or more) and pressures in a direction perpendicular to the pressure receiving surface; N (N is a natural number equal to or greater than 3) temperature sensor cells are arranged between the M shear force sensor cells and a support surface, overlapping the arrangement region of the M shear force sensor cells, and are used for temperature compensation of each of the M shear force sensor cells; and a controller connected to the M shear force sensor cells and the N temperature sensor cells, the controller detecting the shear force by the M shear force sensor cells while performing temperature compensation of the pressing force by the N temperature sensor cells; Equipped with Each of the M shear force sensor cells has a first drive electrode and a second drive electrode separated by a gap; a detection electrode overlapping the gap, the first drive electrode, and the second drive electrode, the detection electrode forming a first capacitance between the detection electrode and the first drive electrode and forming a second capacitance between the detection electrode and the second drive electrode; an elastically deformable insulating elastic body disposed between the first driving electrode, the second driving electrode and the detection electrode; having each of the N temperature sensor cells shares at least one of the first drive electrode and the second drive electrode or the detection electrode with at least one of the M shear force sensor cells as a first compensation electrode; Each of the N temperature sensor cells has a second compensation electrode facing the first compensation electrode; a dielectric material that is different from the insulating elastic body and that is disposed between the first compensation electrode and the second compensation electrode; and a plurality of first wirings for connecting the controller with the first driving electrodes, the second driving electrodes, and the detection electrodes of the M shear force sensor cells; a plurality of second wirings for connecting the controller and the second compensation electrodes of the N temperature sensor cells; Further equipped with the first driving electrodes and the second driving electrodes of the M shear force sensor cells are disposed on a first conductive layer; A shear force detection device, wherein the detection electrodes of the M shear force sensor cells are disposed on a second conductive layer opposed to the first conductive layer.

2. The insulating elastomer is a foam. The dielectric is a solid film made of resin.

2. The shear force detection device according to claim 1.

3. the number of the shear force sensor cells is equal to the number of the temperature sensor cells, and the shear force sensor cells and the temperature sensor cells are in one-to-one correspondence with each other; The shear force detection device according to claim 1 or 2.

4. a plurality of the shear force sensor cells are associated with one of the temperature sensor cells; The shear force detection device according to claim 1 or 2.

5. A temperature compensation method for a shear force detection device comprising: M (M is a natural number of 4 or more) shear force sensor cells for detecting a shear force applied to a pressure-receiving surface and a pressing force perpendicular to the pressure-receiving surface; N (N is a natural number of 4 or more) temperature sensor cells arranged in a manner overlapping with each other in an arrangement region of the shear force sensor cells and used for temperature compensation of the shear force sensor cells; and a controller connected to the shear force sensor cells and the temperature sensor cells for detecting the shear force and the pressing force by the shear force sensor cells while performing temperature compensation of the pressing force by the temperature sensor cells, comprising: each of the N temperature sensor cells shares at least one of the first drive electrode and the second drive electrode or the detection electrode of each of the M shear force sensor cells as a first compensation electrode with at least one of the M shear force sensor cells; Each of the N temperature sensor cells further includes a second compensation electrode facing the first compensation electrode, and a dielectric material disposed between the first compensation electrode and the second compensation electrode, Each of the M shear force sensor cells further includes an insulating elastic body disposed between the first driving electrode and the second driving electrode and between the detection electrode and the detection electrode, The insulating elastomer and the dielectric material are different from each other, A temperature compensation method for a shear force detection device, wherein the controller applies an AC voltage to one of the first compensation electrode and the second compensation electrode and measures an electric charge at the other of the first compensation electrode and the second compensation electrode when detecting the temperatures of the N temperature sensor cells.

6. The insulating elastomer is a foam. the dielectric is a solid film made of resin, detecting a temperature by regarding a change in capacitance of the temperature sensor cell due to a pressing force applied to the temperature sensor cell as zero while detecting the pressing force of the shear force sensor cell; A method for temperature compensation in a shear force detection device according to claim 5.

Images