Stress sensor and stress detection sheet

Abstract

The invention provides a stress sensor which can greatly reduce the number of wires of the stress sensor and is easy to increase in size even when the detection resolution is maintained. In the stress sensor (1), M first grooves (35) extending in a first direction in each row and M second grooves (36) extending in a second direction intersecting the first direction are provided between a first column electrode (31) and a second column electrode (32) of each pair in a second electrode layer (3). The first row electrodes (21) in each pair are arranged so as to overlap the N rows of first grooves (35). The second row electrodes (22) in each pair are arranged so as to overlap the N columns of second grooves (36). A detection circuit (5) drives N pairs of first column electrodes (31) and second column electrodes (32) at different timings for each electrode.

Description

Technical Field

[0001] The present invention relates to a stress sensor for detecting stress, and in particular to a stress sensor for detecting shear stress and compression stress. Background Art

[0002] Conventionally, there is a stress sensor using a sheet as described in Patent Document 1 (Japanese Patent No. 6699954). This stress sensor detects compressive stress (pressing force) by compressing an elastic body in the stress sensor by pressing the sheet surface in a normal direction. In addition, this stress sensor can detect shear stress generated in two different directions (X direction and Y direction) that are in-plane directions relative to the sheet surface.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent document 1: Japanese Patent No. 6699954. Summary of the invention

[0006] Problem that the invention aims to solve

[0007] Fig.12 The basic cross-sectional structure of a detection piece of a conventional stress sensor described in Patent Document 1 that is capable of detecting shear stress and compressive stress in two directions is shown. Fig.12 The detection piece 900 of the conventional stress sensor shown has Fig.13 The j first strip electrodes 910 shown, Fig.14 k second strip electrodes 920, and Fig.15 There are j×k segment electrodes 930 shown. A groove 935 is formed between the segment electrodes 930 adjacent to each other.

[0008] When the configuration is considered in detail, the first strip electrode 910 can be classified into j electrodes, from the first strip electrode α1 arranged in the first row to the first strip electrode αj arranged in the j row. When the configuration is considered in detail, the second strip electrode 920 can be classified into k electrodes, from the second strip electrode β1 arranged in the first column to the second strip electrode βk arranged in the k column. Furthermore, when the configuration is considered in detail, the segmented electrode 930 can be classified into j×k electrodes, from the segmented electrode γ(1,1) arranged in the first row and the first column to the segmented electrode γ(j,k) arranged in the j row and the k column.

[0009] The j×k segment electrodes 930 are formed on the flexible wiring substrate 940. The flexible wiring substrate 940 is provided with j×k through holes 945 connected to the j×k segment electrodes 930. The j×k through holes 945 are connected to j×k wirings 950 for connecting to an external circuit.

[0010] An elastic body 960 is arranged between the segment electrode 930 and the second strip electrode 920. When a force is applied to the detection piece 900 of the conventional stress sensor from the outside, the elastic body 960 is deformed. When the elastic body 960 is deformed, the capacitance between the first strip electrode 910 and the second strip electrode 920 and the segment electrode 930 changes. Shear stress and compressive stress can be detected based on the change in capacitance. In addition, in order to insulate the first strip electrode 910 from the second strip electrode 920, an insulating film 971 is arranged between the first strip electrode 910 and the second strip electrode 920. In addition, in order to mitigate the influence of the external electric field, conductive films 981 and 982 connected to the common potential GND are arranged on the surface and back of the detection piece 900 of the stress sensor. For insulation, an insulating film 972 is arranged between the conductive film 981 and the first strip electrode 910, and an insulating film 973 is arranged between the conductive film 982 and the wiring 950.

[0011] In a structure such as the detection piece 900 of the conventional stress sensor, for example, in order to detect shear stress in two rows and two columns, it is necessary to Fig.16 As shown in FIG. 1 , 9 segment electrodes 930, two first strip electrodes 910, and two second strip electrodes 920 are arranged in 3 rows and 3 columns. Fig.16 When the detection piece 900 is used, the shear stress in the X direction and the shear stress in the Y direction of 2 rows and 2 columns can be detected.

[0012] As described above, in the detection piece 900 of the conventional stress sensor, the plurality of segment electrodes 930 , the first strip electrode 910 , and the second strip electrode 920 arranged in a matrix form can detect compressive stress and shear stress at a plurality of locations.

[0013] However, in order to realize the connection between the external circuit and the j×k segment electrodes 930, j×k wirings 950 are required. In addition, a flexible wiring substrate 940 capable of forming a through hole 945 is required in order to connect the wiring 950 and the segment electrode 930.

[0014] For those with Fig.12It is difficult to enlarge the existing stress sensor of the detection sheet 900 as shown in the figure without increasing the number of wirings while maintaining the detection resolution. When the detection sheet 900 is enlarged while maintaining the detection resolution, the number of segmented electrodes 930 increases, and the number of wirings 950 increases. When the number of wirings 950 increases, the number of connector pins for the external circuit connected to the flexible wiring substrate 940 also increases, and the assembly and disassembly of the detection sheet 900 and the external circuit becomes difficult. In addition, when the detection sheet 900 is enlarged, the flexible wiring substrate 940 used by the detection sheet 900 is also enlarged, and the flexible wiring substrate 940 becomes expensive.

[0015] An object of the present invention is to provide a stress sensor that can significantly reduce the number of wirings of the stress sensor even if the size of the stress sensor is increased while maintaining the detection resolution, thereby facilitating the increase in size.

[0016] Solutions for solving problems

[0017] Hereinafter, a plurality of aspects will be described as means for solving the problems. These aspects can be arbitrarily combined as needed.

[0018] A stress sensor according to one aspect of the present invention comprises: a first electrode layer and a second electrode layer, an insulating elastic layer, and a detection circuit. The first electrode layer and the second electrode layer are arranged to overlap with M×N detection areas for detection divided into M rows and N columns (where M and N are integers greater than 2), and the first electrode layer and the second electrode layer face each other. The insulating elastic layer is located between the first electrode layer and the second electrode layer, electrically insulates the two electrode layers, and is formed of an elastically deformable material. The detection circuit is connected to the first electrode layer and the second electrode layer. The first electrode layer includes: M pairs of first row electrodes and second row electrodes extending across N columns and insulated from each other; and M first row wirings and M second row wirings connecting the M pairs of first row electrodes and second row electrodes to the detection circuit. The second electrode layer includes: N pairs of first column electrodes and second column electrodes extending across M rows and insulated from each other; and N first column wirings and N second column wirings connecting the N pairs of first column electrodes and second column electrodes to the detection circuit. In the second electrode layer, between each pair of first column electrodes and second column electrodes, there are M first grooves extending in the first direction in each row and M second grooves extending in the second direction intersecting the first direction. The first row electrodes in each pair are arranged to overlap with the first grooves in the N columns. The second row electrodes in each pair are arranged to overlap with the second grooves in the N columns. The detection circuit is configured to: by driving the N pairs of first column electrodes and second column electrodes at different timings according to each electrode, the shear stress orthogonal to the first direction in the first grooves arranged in the M rows and N columns is detected, the shear stress orthogonal to the second direction in the second grooves arranged in the M rows and N columns is detected, and the pressing force in the M rows and N columns where the M pairs of first row electrodes and second row electrodes intersect with the N pairs of first column electrodes and second column electrodes.

[0019] The stress sensor having such a structure can significantly reduce the number of wirings used to detect shear stress and compressive stress in the first and second directions of M rows and N columns by providing M first row wirings and M second row wirings and N first column wirings.

[0020] The stress sensor can be configured such that the first row electrode and the second row electrode and the first row wiring and the second row wiring are formed by the same component arranged in the same plane, and the first column electrode and the second column electrode and the first column wiring and the second column wiring are formed by the same component arranged in the same plane. The stress sensor configured in this way can make the detection sheet including the first row electrode and the second row electrode, the first row wiring and the second row wiring, the first column electrode and the second column electrode and the first column wiring and the second column wiring thinner, for example. In addition, since the distances between the electrodes arranged in rows and columns are equal, the difference in sensitivity of the shear stress in the first direction and the second direction caused by the difference in the distances between the electrodes can be eliminated.

[0021] In the stress sensor, in each first row electrode, the connection between adjacent stress detection parts is thinner than the plurality of stress detection parts overlapping the first groove. Compared with a case where the connection is not thin, the stress sensor configured in this way can suppress inter-axial interference.

[0022] The stress sensor can be configured such that each first row electrode overlaps the first groove at a plurality of locations in each detection region. Compared with a case where the first row electrode and the first groove overlap at only one location, the stress sensor configured in this way is less likely to cause inter-axial interference.

[0023] The stress sensor can be configured such that each second row electrode overlaps the second groove at a plurality of locations in each detection region. Compared with a case where the second row electrode overlaps the second groove at only one location, the stress sensor configured in this way is less likely to cause inter-axial interference.

[0024] The stress sensor can be configured to have an elastic layer on the surface that overlaps with the M×N detection regions. In the stress sensor configured in this way, stress is dispersed by the elastic layer, and inter-axial interference is less likely to occur.

[0025] The stress sensor can be configured to have a silicon film overlapping M×N detection regions on the back surface. In the stress sensor configured in this way, the silicon film on the back surface prevents, for example, a detection sheet including the detection regions from slipping, making it easy to measure shear stress.

[0026] A stress detection sheet according to one aspect of the present invention has a first electrode layer, a second electrode layer, and an insulating elastomer layer. The first electrode layer and the second electrode layer are arranged to overlap with M×N detection areas for detection divided into M rows and N columns (where M and N are integers greater than 2), and the first electrode layer and the second electrode layer face each other. The insulating elastomer layer is located between the first electrode layer and the second electrode layer, electrically insulates the two electrode layers, and is formed of an elastically deformable material. The first electrode layer includes: M pairs of first row electrodes and second row electrodes extending across N columns and insulated from each other; and M first row wirings and M second row wirings for connecting the M pairs of first row electrodes and second row electrodes to circuits outside the sheet. The second electrode layer includes: N pairs of first column electrodes and second column electrodes extending across M rows and insulated from each other; and N first column wirings and N second column wirings for connecting the N pairs of first column electrodes and second column electrodes to circuits outside the sheet. In the second electrode layer, between the first column electrode and the second column electrode of each pair, there are M first grooves extending in a first direction in each row and M second grooves extending in a second direction intersecting the first direction. The first row electrode in each pair is configured to overlap with the first grooves of the N columns. The second row electrode in each pair is configured to overlap with the second grooves of the N columns.

[0027] The stress detection sheet having such a structure can significantly reduce the number of wirings used to detect shear stress and compressive stress in the first and second directions of M rows and N columns by providing M first row wirings and M second row wirings and N first column wirings.

[0028] Effects of the Invention

[0029] According to the stress sensor of the present invention, even if the size is increased while maintaining the detection resolution, the number of wirings can be significantly reduced, and the size can be increased easily. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 FIG. 1 is a schematic diagram showing a structural example of a stress sensor according to the present invention.

[0031] Figure 2 It is a plan view showing a basic structural example of first electrode layers and second electrode layers of four rows and four columns according to the first embodiment.

[0032] Figure 3 This is a flow chart for explaining the process of measuring the basic capacitance of the detection circuit.

[0033] Figure 4 It is a top view of the capacitor schematically showing each detection area involved in the capacitance measurement according to the first embodiment.

[0034] Figure 5 It is a schematic cross-sectional view showing the cross-sectional structure of the detection piece of the stress sensor according to the first embodiment.

[0035] Figure 6 It is a schematic diagram showing a configuration example of a stress sensor according to a second embodiment.

[0036] Figure 7 To express Figure 6 A top view of the structure of the first electrode layer.

[0037] Figure 8 To express Figure 6 A top view of the structure of the second electrode layer.

[0038] Fig. 9 It is a top view schematically showing the capacitor of each detection area involved in the capacitance measurement according to the second embodiment.

[0039] Fig.10 It is a schematic cross-sectional view showing the cross-sectional structure of a detection piece of the stress sensor according to the second embodiment.

[0040] Fig.11 It is a schematic plan view showing a configuration example of a detection piece of a stress sensor according to a third embodiment.

[0041] Fig.12 It is a schematic cross-sectional view showing the cross-sectional structure of a detection piece of a conventional stress sensor.

[0042] Fig.13 FIG. 1 is a plan view showing a first strip-shaped electrode of a detection sheet of a conventional stress sensor.

[0043] Fig.14 FIG. 1 is a plan view showing a first strip-shaped electrode of a detection sheet of a conventional stress sensor.

[0044] Fig.15 FIG. 1 is a top view showing a segmented electrode of a detection piece of a conventional stress sensor.

[0045] Fig.16 It is a schematic plan view for explaining the structure of a conventional detection piece for detecting shear stress in the X direction and shear stress in the Y direction, and a pressing force applied to each segment electrode of two rows and two columns. DETAILED DESCRIPTION

[0046] <First Embodiment>

[0047] (1) Basic structure of stress sensor

[0048] exist Figure 1 The basic structure of the stress sensor 1 according to the first embodiment is shown in FIG. Figure 1 As shown, the stress sensor 1 has a first electrode layer 2, a second electrode layer 3, an insulating elastic layer 4, and a detection circuit 5. Figure 1 In order to make the first electrode layer 2, the second electrode layer 3 and the insulating elastic layer 4 look easy to distinguish, the first electrode layer 2, the second electrode layer 3 and the insulating elastic layer 4 are drawn to be staggered with each other, but this is not actually the case.

[0049] The stress sensor 1 has M×N detection areas DA for detection, which are divided into M rows and N columns (where M and N are integers greater than 2). In the stress sensor 1, stress can be detected individually in each detection area DA. In other words, pressing force (compression stress) can be detected at M×N locations, shear stress in the first direction can be detected at M×N locations, and shear stress in the second direction can be detected at M×N locations. Figure 1 The portion other than the detection circuit 5 in the illustrated stress sensor 1 is the stress detection sheet 8 .

[0050] The first electrode layer 2 includes M first row wirings 23 and M second row wirings 24 for connecting to the detection circuit 5. Figure 1The first row wiring 23 and the second row wiring 24 of the 1st row, and the first row wiring 23 and the second row wiring 24 of the Mth row are described, and the description of the first row wiring 23 and the second row wiring 24 of other rows is omitted.

[0051] The second electrode layer 3 includes N first column wirings 33 and N second column wirings 34 for connecting to the detection circuit 5. Figure 1 , the first column wiring 33 and the second column wiring 34 of the 1st column, and the first column wiring 33 and the second column wiring 34 of the Nth column are described, and the description of the first column wiring 33 and the second column wiring 34 of the other columns is omitted.

[0052] The insulating elastic layer 4 is formed of an elastically deformable insulating material and is located between the first electrode layer 2 and the second electrode layer 3 to electrically insulate the first electrode layer 2 from the second electrode layer 3 .

[0053] (2) Basic structure of each detection area

[0054] exist Figure 2 An example of a basic structure of the first electrode layer 2 and the second electrode layer 3 with 4 rows and 4 columns is shown in FIG. Figure 2 2 shows the structure of the first electrode layer 2 and the second electrode layer 3 when the stress detection sheet 8 having the detection area DA arranged therein is viewed from the surface. Figure 2 Only the structures of the first electrode layer 2 and the second electrode layer 3 in the stress detection sheet 8 are described, and description of other structures such as the insulating elastic layer 4 is omitted.

[0055] The first electrode layer 2 includes: two pairs of first row electrodes 21 and second row electrodes 22 extending across two columns and insulated from each other; and two first row wirings 23 and two second row wirings 24 connecting the two pairs of first row electrodes 21 and second row electrodes 22 to the detection circuit 5.

[0056] The second electrode layer 3 includes: two pairs of first column electrodes 31 and second column electrodes 32 extending across two rows and insulated from each other; and two first column wirings 33 and two second column wirings 34 connecting the two pairs of first column electrodes 31 and second column electrodes 32 to the detection circuit 5 .

[0057] In the second electrode layer 3 , each pair of the first column electrode 31 and the second column electrode 32 has two first grooves 35 extending in the first direction in each row and two second grooves 36 extending in the second direction intersecting the first direction.

[0058] The first row electrode 21 in each pair is arranged to overlap with the two columns of the first grooves 35. In addition, the second row electrode 22 in each pair is arranged to overlap with the two columns of the second grooves 36. In addition, the grooves overlapping with the second row electrode 22 have a portion slightly extending in the first direction, and the second grooves 36 are portions other than such portions extending in the first direction.

[0059] exist Figure 2 The detection area DA configured in the 1st row and 1st column is the detection area DA(1,1), the detection area DA configured in the 2nd row and 1st column is the detection area DA(2,1), the detection area DA configured in the 1st row and 2nd column is the detection area DA(1,2), and the detection area DA configured in the 2nd row and 2nd column is the detection area DA(2,2).

[0060] (3) Stress detection in detection circuit

[0061] The detection circuit 5 drives two pairs of first column electrodes 31 and second column electrodes 32 at different timings for each electrode. That is, the first column electrodes 31 and the second column electrodes 32 are driving electrodes, and the first row electrodes 21 and the second row electrodes 22 are sensing electrodes.

[0062] like Figure 3 As shown, the detection circuit 5 first drives the first column electrode 31 of the first column (step ST1). Then, the detection circuit 5 uses the first row electrode 21 and the second row electrode 22 of the first row to measure the capacitance with the first column electrode 31 of the first column, and uses the first row electrode 21 and the second row electrode of the second row to measure the capacitance with the first column electrode 31 of the first column (step ST2). Drive the second column electrode 32 of the first column (step ST3). Then, the detection circuit 5 uses the first row electrode 21 and the second row electrode 22 of the first row to measure the capacitance with the second column electrode 32 of the first column, and uses the first row electrode 21 and the second row electrode of the second row to measure the capacitance with the second column electrode 32 of the first column (step ST4). Using the measurement results of the capacitance of the first column obtained through steps ST1 to ST4, the detection circuit 5 detects the shear stress in the first direction, the shear stress in the second direction, and the pressing force in 1 row and 1 column and 2 rows and 1 column. In other words, in steps ST1 to ST4 , the shear stress in the first direction, the shear stress in the second direction, and the pressing force are detected in the detection areas DA( 1 , 1 ) and DA( 2 , 1 ).

[0063] Next, the detection circuit 5 drives the first column electrode 31 of the second column (step ST5). Then, the detection circuit 5 uses the first row electrode 21 and the second row electrode 22 of the first row to measure the capacitance with the first column electrode 31 of the second column, and uses the first row electrode 21 and the second row electrode of the second row to measure the capacitance with the first column electrode 31 of the second column (step ST6). Drive the second column electrode 32 of the second column (step ST7). Then, the detection circuit 5 uses the first row electrode 21 and the second row electrode 22 of the first row to measure the capacitance with the second column electrode 32 of the second column, and uses the first row electrode 21 and the second row electrode of the second row to measure the capacitance with the second column electrode 32 of the second column (step ST8). Using the measurement results of the capacitance of the second column obtained through steps ST5 to ST8, the detection circuit 5 detects the shear stress in the first direction, the shear stress in the second direction, and the pressing force in 1 row and 2 columns and 2 rows and 2 columns. In other words, in steps ST5 to ST8 , the shear stress in the first direction, the shear stress in the second direction, and the pressing force are detected in the detection areas DA( 1 , 2 ) and DA( 2 , 2 ) of the second row.

[0064] Furthermore, when the stress sensor 1 detects the shear stress in the first direction, the shear stress in the second direction, and the pressing force, calibration is performed before the detection to measure the capacitance in a state where no stress is applied.

[0065] (4) Calculation for stress detection

[0066] Next, use Figure 4 The detection of the shear stress in the first direction, the shear stress in the second direction, and the pressing force in each detection area DA will be described. Figure 4 In FIG. 1 , four capacitors CoR, CoL, CoU, and CoD formed in one detection area DA are shown by oblique lines. Capacitor CoL is formed by the overlapping portion of the first row electrode 21 and the first column electrode 31. Capacitor CoR is formed by the overlapping portion of the first row electrode 21 and the second column electrode 32. Capacitor CoU is formed by the overlapping portion of the second row electrode 22 and the first column electrode 31. Capacitor CoD is formed by the overlapping portion of the second row electrode 22 and the second column electrode 32.

[0067] When a load is applied, the capacitances of the four capacitors CoR, CoL, CoU, and CoD are denoted as CR, CL, CU, and CD, respectively. In addition, when no load is applied, the capacitances of the capacitors CoR, CoL, CoU, and CoD are denoted as CR, CL, CU, and CD, respectively. BL , CL BL , CU BL , CD BL .

[0068] The capacitance CL is a capacitance generated between the first row electrode 21 and the first column electrode 31. The capacitance CR is a capacitance generated between the first row electrode 21 and the second column electrode 32. The capacitance CU is a capacitance generated between the second row electrode 22 and the first column electrode 31. The capacitance CD is a capacitance generated between the second row electrode 22 and the second column electrode 32.

[0069] When using constants K1, K2, Kv and CU, CD, CL, CR, the shear stresses F1, F2 in the first and second directions and the compressive stress Fv in the direction perpendicular to the surface of the stress detection piece 8 can be calculated as shown in the following equations [1], [2] and [3].

[0070] F1=K1×{CD / (CU+CD)-CD BL / (CU BL +CD BL )}…[1]

[0071] F2=K2×{CR / (CL+CR)-CR BL / (CL BL +CR BL )}…[2]

[0072] Fv=Kv×{(CL+CR+CU+CD) / (CL BL +CR BL +CU BL +CD BL )-1}…[3]

[0073] When the above F1, F2 and Fv are rewritten using the following P1, P2, Pv, they become Formula [4], Formula [5] and Formula [6].

[0074] P1=CD / (CU+CD)-1 / 2

[0075] P2=CR / (CL+CR)-1 / 2

[0076] Pv=CL+CR+CU+CD

[0077] F1=K1×[P1-P1 BL ]…[4]

[0078] F2=K2×[P2-P2 BL ]…[5]

[0079] Fv=Kv×Pv / Pv BL …[6]

[0080] The subscript BL represents the values ​​of P1, P2, and Pv in a state where no stress is applied. In addition, K1 is the reciprocal of the slope of the sensitivity curve [P1 / F1], K2 is the reciprocal of the slope of the sensitivity curve [P2 / F2], and Kv is the reciprocal of the slope of the sensitivity curve [Pv / Fv].

[0081] like Figure 4 As shown, in each first row electrode 21, the connection portion 21b between adjacent stress detection portions 21a is thinner than the stress detection portion 21a overlapping the first groove 35. The stress detection portion 21a is rectangular in shape, and the long side extends along the first groove 35. Compared with the case where the widths of the stress detection portion 21a and the connection portion 21b are the same, the width of the stress detection portion 21a becomes larger, so that the change in capacitance relative to the stress change becomes larger, and thus it becomes easier to detect stress. In addition, by making the width of the connection portion 21b smaller, cross-axis interference can be suppressed. The cross-axis interference mentioned here refers to the phenomenon that the stress of the detection object is affected by the stress outside the detection object, for example, when detecting the first shear stress, the magnitude of the first shear stress changes according to the magnitude of the compressive stress.

[0082] (5) Cross-sectional structure of the test piece

[0083] exist Figure 5 , an overview of the basic cross-sectional structure of the stress detection sheet 8 of the stress sensor 1 according to the first embodiment is shown. The stress detection sheet 8 includes an upper electrode layer UDL, a lower electrode layer LDL, and an insulating elastic layer 4. A first electrode layer 2 is arranged on the insulating elastic layer 4, and a second electrode layer 3 is arranged below the insulating elastic layer 4. Specifically, for example, the first electrode layer 2 is bonded to the upper surface of the insulating elastic layer 4 by an adhesive, and the second electrode layer 3 is bonded to the lower surface of the insulating elastic layer 4 by an adhesive. In other words, the insulating elastic layer 4 is bonded to the upper electrode layer UDL and the lower electrode layer LDL by an adhesive in such a manner that the insulating elastic layer 4 is sandwiched between the upper electrode layer UDL and the lower electrode layer LDL.

[0084] As the insulating elastic body layer 4, for example, a foamed material is used as an elastically deformable material.

[0085] In the upper electrode layer UDL, a protective layer 71, a conductive layer 72, an insulating layer 73, and a first electrode layer 2 are provided in order from the top. The protective layer 71 and the insulating layer 73 are composed of, for example, insulating films. It is preferable to use an elastically deformable material that can disperse pressure for the protective layer 71. In addition, the conductive layer 72 and the first electrode layer 2 are composed of, for example, a conductive adhesive (conductive paste). In order to mitigate the influence of an external electric field, the conductive layer 72 is connected to a common potential GND.

[0086] In the lower electrode layer LDL, a protective layer 81, a conductive layer 82, an insulating layer 83, and a second electrode layer 3 are sequentially provided from the bottom. The protective layer 81 and the insulating layer 83 are composed of, for example, an insulating film. It is preferred that an anti-slip sheet having anti-slip properties formed of, for example, a silicone resin, an acrylic resin, an acrylic-silicone resin, or rubber is used for the protective layer 81. In addition, the conductive layer 82 and the second electrode layer 3 are composed of, for example, a conductive adhesive (conductive paste). In order to mitigate the influence of an external electric field, the conductive layer 82 is connected to a common potential GND.

[0087] <Second embodiment>

[0088] (6) Overall structure of stress sensor

[0089] exist Figure 6 The overall structure of the stress sensor 1 according to the second embodiment is shown in FIG. Figure 6 As shown, the stress sensor 1 has a first electrode layer 2, a second electrode layer 3, and a detection circuit 5. Figure 6 The insulating elastomer layer 4 is not shown, but Figure 1 Similarly, for stress sensor 1, Figure 6 The stress sensor 1 also has an insulating elastomer layer 4 (refer to Fig.10 ).

[0090] Figure 6 The stress sensor 1 has 9 detection areas DA for detection, which are divided into 3 rows and 3 columns. When the detection area DA is distinguished by the place where it is configured, it is indicated by adding rows and columns. For example, the detection area of ​​M rows and N columns is marked with "DA(M,N)". For example, the detection area DA(2,2) is configured in the 2nd row and the 2nd column. In the detection area DA(2,2), the pressing force (compression stress) in the 2nd row and the 2nd column, the shear stress in the first direction, and the shear stress in the second direction can be detected. Figure 6 The portion other than the detection circuit 5 in the illustrated stress sensor 1 is a stress detection sheet 8 .

[0091] The detection circuit 5 includes a sensor circuit 51 and a drive circuit 52 .

[0092] (7) Structure of the First Electrode Layer and the Second Electrode Layer

[0093] exist Figure 7The first electrode layer 2 is shown in FIG. The first row electrodes 21 and the second row electrodes 22 are distinguished by the locations where they are arranged, and are indicated by adding rows, for example, the electrode arranged in the first row is marked with "-1". The first electrode layer 2 includes: three pairs of first row electrodes 21-1 to 21-3 and second row electrodes 22-1 to 22-3 extending across three columns and insulated from each other; and three first row wirings 23-1 to 23-3 and three second row wirings 24-1 to 24-3 connecting the three pairs of first row electrodes 21-1 to 21-3 and second row electrodes 22-1 to 22-3 to the sensor circuit 51 of the detection circuit 5.

[0094] exist Figure 8 The second electrode layer 3 is shown in FIG. The first column electrodes 31 and the second column electrodes 32 are indicated by adding a column when distinguished by the location where they are arranged, for example, the electrode arranged in the first column is marked with "-1". The second electrode layer 3 includes: three pairs of first column electrodes 31-1 to 31-3 and second column electrodes 32-1 to 32-3 extending across three columns and insulated from each other; and three first column wirings 33-1 to 33-3 and three second column wirings 34-1 to 34-3 connecting the three pairs of first column electrodes 31-1 to 31-3 and second column electrodes 32-1 to 32-3 to the driving circuit 52 of the detection circuit 5.

[0095] (8) Stress detection by detection circuit

[0096] The driving circuit 52 of the detection circuit 5 drives the three pairs of the first column electrodes 31 and the second column electrodes 32 at different timings for each electrode. For example, the driving circuit 52 first drives the first column electrode 31-1 and the second column electrode 32-1 of the first column, then drives the first column electrode 31-2 and the second column electrode 32-2 of the second column, and then drives the first column electrode 31-3 and the second column electrode 32-3 of the third column.

[0097] Among them, use Fig. 9 The following describes a case where the shear stress can be calculated by focusing on one detection area DA. Fig. 9 , driving electrodes that contribute to detection of the detection area DA located at the 3rd row and the 3rd column are shown. In the detection area DA(3,3) at the 3rd row and the 3rd column, the driving electrodes include the first column electrode 31-3 and the second column electrode 32-3, and the sensing electrodes include the first row electrode 21-3 and the second row electrode 22-3.

[0098] The capacitors formed by the overlapping portion of the first row electrode 21 and the first column electrode 31 are four capacitors CoL1, CoL2, CoL3, and CoL4. The capacitors formed by the overlapping portion of the first row electrode 21 and the second column electrode 32 are four capacitors CoR1, CoR2, CoR3, and CoR4. The capacitors formed by the overlapping portion of the second row electrode 22 and the first column electrode 31 are two capacitors CoD1 and CoD2. The capacitors formed by the overlapping portion of the second row electrode 22 and the second column electrode 32 are two capacitors CoU1 and CoU2.

[0099] Each first row electrode 21 is configured to overlap with the first groove 35 at multiple locations (here, 4 locations) in each detection area DA. Each second row electrode 22 is configured to overlap with the second groove 36 at multiple locations (here, 2 locations) in each detection area DA. In each detection area DA, the first row electrode 21 and the first groove 35 overlap at multiple locations, thereby configuring the overlapping locations to be wide, so that inter-axial interference is less likely to occur compared with a case where the overlapping location is only one. In each detection area DA, the second row electrode 22 and the second groove 36 overlap at multiple locations, thereby configuring the overlapping locations to be wide, so that inter-axial interference is less likely to occur compared with a case where the overlapping location is only one.

[0100] Second Embodiment Fig. 9 The capacitors CoL1, CoL2, CoL3, and CoL4 are equivalent to those described in the first embodiment. Figure 4 That is, when the capacitances of capacitors CoL1, CoL2, CoL3, and CoL4 are expressed as CL1, CL2, CL3, and CL4, CL=CL1+CL2+CL3+CL4 can be substituted into CL in equations [2] and [3]. Therefore, CL in equations [2] and [3] is BL Also by CL BL =CL1 BL +CL2 BL +CL3 BL +CL4 BL To give.

[0101] Similarly, the second embodiment Fig. 9 The capacitors CoR1, CoR2, CoR3, and CoR4 are equivalent to those described in the first embodiment. Figure 4 That is, when the capacitances of capacitors CoR1, CoR2, CoR3, and CoR4 are expressed as CR1, CR2, CR3, and CR4, CR=CR1+CR2+CR3+CR4 can be substituted into CR in equations [2] and [3]. Therefore, CR in equations [2] and [3] is BL Also by CR BL =CR1BL +CR2 BL +CR3 BL +CR4 BL To give.

[0102] Second Embodiment Fig. 9 The capacitors CoU1 and CoU2 are equivalent to those described in the first embodiment. Figure 4 That is, when the capacitances of capacitors CoU1 and CoU2 are denoted as CU1 and CU2, CU=CU1+CU2 can be substituted into CU of equations [1] and [3]. Therefore, CU of equations [1] and [3] is BL Also by CU BL =CU1 BL +CU2 BL To give.

[0103] Second Embodiment Fig. 9 The capacitors CoD1 and CoD2 are equivalent to those described in the first embodiment. Figure 4 That is, when the capacitances of capacitors CoD1 and CoD2 are expressed as CD1 and CD2, CD=CD1+CD2 can be substituted into CD in equations [1] and [3]. Therefore, CD in equations [1] and [3] is BL Also by CD BL =CD1 BL +CD2 BL To give.

[0104] That is, the shear stress F1 in the first direction, the shear stress F2 in the second direction, and the compressive stress Fv in the direction perpendicular to the surface of the stress detection piece 8 can be calculated using CL1 to CL4, CL1 BL ~CL4 BL ,CR1~CR4,CR1 BL ~CR4 BL , CU1~CU2, CU1 BL ~CU2 BL 、CD1~CD2、CD1 BL ~CD2 BL to calculate.

[0105] exist Fig. 9 In the figure, the detection area DA(3,3) in the 3rd row and 3rd column is listed as an example for explanation. For each detection area DA(M,N) in M ​​rows and N columns, the shear stress F1 in the first direction, the shear stress F2 in the second direction, and the compressive stress Fv in the direction perpendicular to the surface of the stress detection sheet 8 can be calculated in the same way as the case of the detection area DA(3,3).

[0106] (9) Cross-sectional structure of the test piece

[0107] exist Fig.10 The figure shows an overview of the basic cross-sectional structure of the stress detection sheet 8 of the stress sensor 1 according to the second embodiment. A first electrode layer 2 is arranged on the insulating elastic layer 4, and a second electrode layer 3 is arranged below the insulating elastic layer 4. The first electrode layer 2 is bonded to the upper surface of the insulating elastic layer 4 by an adhesive 41, and the second electrode layer 3 is bonded to the lower surface of the insulating elastic layer 4 by an adhesive 42. The adhesive 41 and the adhesive 42 are, for example, silicone adhesives. As the silicone adhesive, for example, a silicone rubber adhesive is used. The thickness of the adhesive 41 and the adhesive 42 is, for example, 10 to 100 μm.

[0108] For the insulating elastomer layer 4, an elastically deformable material such as a foam material is used. Examples of the foam material include silicone rubber, polyurethane, and polyethylene. Examples of materials with large compression deformation include materials in which gas is finely dispersed in a resin and molded into a foamed or porous shape. Examples of the material of the foam include silicone, polyurethane, polyethylene, and polystyrene. The thickness of the insulating elastomer layer 4 can be appropriately selected from the range of 2μm to 5mm. The protective layer 71 and the insulating layer 73 are composed of an insulating film. It is preferred to use an elastically deformable material that can disperse pressure for the protective layer 71. Examples of the insulating film used for the protective layer 71 and the insulating layer 73 include silicone films. The thickness of the insulating film is, for example, 10 to 100μm.

[0109] In the stress detection sheet 8, a protective layer 71, a conductive layer 72, an insulating layer 73, and a first electrode layer 2 are provided in order from the top. The conductive layer 72 and the first electrode layer 2 are formed of, for example, a conductive adhesive (conductive paste). Here, the conductive layer 72 is provided on the protective layer 71, but the conductive layer 72 and the first electrode layer 2 may also be provided as Figure 5As shown, the conductive layer 72 and the first electrode layer 2 are formed on both sides of the insulating layer 73. By forming the conductive layer 72 and the first electrode layer 2 on both sides of the insulating layer 73, the stress detection sheet 8 can be made thinner. In order to mitigate the influence of the external electric field, the conductive layer 72 is connected to the common potential GND. As a conductive paste constituting the conductive layer 72 and the first electrode layer 2, there is, for example, a silver paste. The thickness of the silver paste is appropriately selected from the range of 0.1μm to 1mm. An adhesive 75 is arranged between the conductive layer 72 and the insulating layer 73. The thickness of the adhesive 75 is, for example, 10 to 100μm. A conductive layer 76 formed of other conductive paste may also be provided on the conductive layer 72. In addition, the conductive layer 76 may also be omitted. The conductive layer 76 is printed using carbon ink, and can serve as a design indicating the position of the component (such as a grid display) and as a layer of the common potential GND. In addition, by using ink, durability can be improved. The conductive layer 76 may be formed between the silicon layer 71 b and the adhesive 71 c , or between the insulating film 71 a and the adhesive 71 c .

[0110] The protective layer 71 is a layer in which the insulating film 71a and the silicon layer 71b on the surface are bonded by an adhesive 71c. The insulating film 71a is, for example, a silicon film. The thickness of the insulating film 71a is, for example, 10 to 100 μm. The silicon layer 71b on the surface is a layer formed of silicon, and the thickness of the layer is, for example, 100 μm to 1 mm. The silicon layer 71b on the surface of the protective layer 71 can disperse the pressure. The silicon layer 71b is an elastic layer that is arranged on the surface, overlaps with the M×N detection areas DA, and has elasticity. The silicon layer 71b can disperse the pressing force to suppress inter-axial interference.

[0111] In the stress detection sheet 8, a protective layer 81, a conductive layer 82, an insulating layer 83, and a second electrode layer 3 are provided in order from the bottom. The protective layer 81 and the insulating layer 83 are composed of, for example, insulating films. It is preferable to use an anti-slip sheet having anti-slip properties formed of, for example, silicone resin, acrylic resin, acrylic-silicone resin or rubber for the protective layer 81. For example, a silicon film can be used for the protective layer 81. The thickness of the protective layer 81 is, for example, 10 μm to 1 mm. The silicon film provided on the protective layer 81 on the back prevents the stress detection sheet 8 from slipping, making it easy to measure the shear stress.

[0112] The insulating layer 83 is made of, for example, a resin film. As the resin film, for example, a polyethylene terephthalate (PET) film. In addition, the conductive layer 82 and the second electrode layer 3 are made of, for example, a conductive adhesive (conductive paste). An adhesive 84 is arranged between the conductive layer 82 and the protective layer 81. The adhesive 84 is, for example, a silicone adhesive. As the silicone adhesive, for example, there is a silicone rubber adhesive. The thickness of the adhesive 84 is, for example, 10 to 100 μm. In order to mitigate the influence of the external electric field, the conductive layer 82 is connected to the common potential GND.

[0113] exist Fig. 9 In the stress detection sheet 8 shown, protective layers 85 and 86 are provided below the conductive layer 82 and above the second electrode layer 3. The protective layers 85 and 86 are formed of, for example, insulating ink. The protective layers 85 and 86 are provided to improve the reliability of the conductive layer 82 and the second electrode layer 3 formed of, for example, silver paste. The protective layers 85 and 86 can prevent migration of the conductive layer 82 and the second electrode layer 3, prevent sulfurization, or prevent disconnection. The protective layers 85 and 86 can also be omitted.

[0114] The first row electrode 21 and the second row electrode 22 and the first row wiring 23 and the second row wiring 24 are formed by the same component arranged in the same plane. In the second embodiment, the first row electrode 21 and the second row electrode 22 and the first row wiring 23 and the second row wiring 24 are formed simultaneously by the same component by, for example, printing silver paste. In addition, the first column electrode 31 and the second column electrode 32 and the first column wiring 33 and the second column wiring 34 are formed by the same component arranged in the same plane. In the second embodiment, the first column electrode 31 and the second column electrode 32 and the first column wiring 33 and the second column wiring 34 are formed simultaneously by, for example, printing silver paste. By forming them simultaneously by the same component like this, it becomes easy to manufacture. In addition, by using the same component formed on the same plane like this, the thickness of the stress detection sheet 8 can be made thinner.

[0115] <Third embodiment>

[0116] (10) Overall structure of the test piece

[0117] exist Fig.11 2 shows an outline of the structure of the stress detection piece 8 of the stress sensor 1 according to the third embodiment. Fig.11 The stress detection sheet 8 has four detection areas DA for detection, which are divided into 2 rows and 2 columns. For example, in the detection area DA (2, 2), the pressing force (compression stress) in the 2nd row and 2nd column, the shear stress in the first direction, and the shear stress in the second direction can be detected.

[0118] The stress detection sheet 8 of the third embodiment is different from the stress detection sheet 8 of the second embodiment in that the arrangement patterns of the first row electrodes 21, the second row electrodes 22, the first column electrodes 31, and the second column electrodes 32 in the plane are different. In the stress detection sheet 8 of the third embodiment, the extension direction of the first row electrodes 21 and the second row electrodes 22, and the extension direction of the first column electrodes 31 and the second column electrodes 32 are not the first direction and the second direction, but are directions inclined 45 degrees relative to the first direction and the second direction, respectively.

[0119] In addition, the third embodiment has two pairs of first row electrodes 21 and second row electrodes 22, which is different from the second embodiment in which one pair of first row electrodes 21 and second row electrodes 22 is provided. The third embodiment has four pairs of first column electrodes 31 and second column electrodes 32, which is different from the second embodiment in which one pair of first column electrodes 31 and second column electrodes 32 is provided.

[0120] (11) Features

[0121] (11-1)

[0122] The stress sensor 1 of the present invention comprises: a first electrode layer 2, a second electrode layer 3, an insulating elastic layer 4, and a detection circuit 5. By providing M first row wirings 23 and second row wirings 24 of the first electrode layer 2, and N first column wirings 33 and second column wirings 34, it is possible to wire the shear stress and the compressive stress in the first direction and the second direction of the M rows and N columns. For example, Figure 2 and Fig.11 In the stress detection sheet 8 of the stress sensor 1 with two rows and two columns shown, two first row wirings 23 and two second row wirings 24 of the first electrode layer 2 and two first column wirings 33 and two second column wirings 34 are provided. Figure 6 In the stress detection sheet 8 of the stress sensor 1 having three rows and three columns shown, three first row wirings 23 and three second row wirings 24 of the first electrode layer 2 and three first column wirings 33 and three second column wirings 34 are provided.

[0123] In contrast, Fig.16 In the detection piece 900 of the conventional stress sensor shown in FIG. 1 , which is capable of detecting shear stress in the X direction and shear stress in the Y direction of 2 rows and 2 columns, two wirings for connecting to the first strip electrode 910 , two wirings for connecting to the second strip electrode 920 , and nine wirings for connecting to the segmented electrode 930 are required.

[0124] Like this with Fig.16 As can be seen from the comparison with the detection piece 900 of the conventional stress sensor shown, the stress sensor 1 of the present invention can significantly reduce the number of wirings for connecting the first electrode layer 2 and the second electrode layer 3 with the detection circuit 5 .

[0125] In the stress sensor 1, the first row electrodes 21 and the second row electrodes 22 and the first column electrodes 31 and the second column electrodes 32 formed on the same surface can be connected to the first row wiring 23 and the second row wiring 24 and the first column wiring 33 and the second column wiring 34 for each row and each column, respectively, as in the first electrode layer 2 and the second electrode layer 3. Therefore, even if the stress detection sheet 8 is enlarged while maintaining the detection resolution, the number of the first row wiring 23 and the second row wiring 24 and the first column wiring 33 and the second column wiring 34 of the stress sensor 1 can be greatly reduced.

[0126] Furthermore, the first column electrodes 31 and the second column electrodes 32 are located on the same plane, and the first column wirings 33 and the second column wirings 34 are located on the same plane. Therefore, the structure of the stress sensor 1 does not require a flexible wiring substrate 940 as in the related art.

[0127] (11-2)

[0128] For example, when using Figure 7 In the first electrode layer 2 of the second embodiment described, the first row electrodes 21 and the second row electrodes 22 and the first row wirings 23 and the second row wirings 24 are formed by the same member arranged in the same plane. Figure 8 In the second electrode layer 3 of the second embodiment described, the first column electrode 31 and the second column electrode 32 and the first column wiring 33 and the second column wiring 34 are configured to be formed by the same component arranged in the same plane. For example, the first row electrode 21 and the second row electrode 22 and the first row wiring 23 and the second row wiring 24 are simultaneously formed from silver paste using a single printing process. Similarly, the first column electrode 31 and the second column electrode 32 and the first column wiring 33 and the second column wiring 34 are simultaneously formed from silver paste using a single printing process, for example.

[0129] The stress detection sheet 8 including the first row electrodes 21 and the second row electrodes 22, the first row wirings 23 and the second row wirings 24, the first column electrodes 31 and the second column electrodes 32, and the first column wirings 33 and the second column wirings 34 constructed in this way can be more Fig.12 The conventional detection sheet 900 shown is thinner.

[0130] In addition, in the prior art, Fig.12As shown in FIG. 1 , the distance between the first strip electrode 910 and the segment electrode 930 is different from the distance between the second strip electrode 920 and the segment electrode 930, so there is a difference in the detection sensitivity of the shear stress in the X direction and the shear stress in the Y direction. In contrast, for example, by using the first row electrode 21 and the second row electrode 22 arranged in the same plane and the first column electrode 31 and the second column electrode 32 arranged in the same plane, the shear stress in the first direction and the shear stress in the second direction are both detected, so the difference in the detection sensitivity of the shear stress in the first direction and the shear stress in the second direction can be eliminated.

[0131] (11-3)

[0132] In use Figure 4 , Figure 7 or Fig.11 In each first row electrode 21 described above, the connection portion 21b between adjacent stress detection portions 21a is thinner than the plurality of stress detection portions overlapping the first groove 35. As a result, the stress sensor 1 can suppress inter-axial interference compared to a case where the connection portion 21b is not thin.

[0133] (11-4)

[0134] Figure 6 or Fig.11 Each of the first row electrodes 21 shown is configured to overlap with the first groove 35 at a plurality of locations in each detection area DA. As a result, in the stress sensor 1, since the overlapping location is arranged in a wider range compared to the case where the first row electrode 21 and the first groove 35 overlap at only one location, inter-axial interference is less likely to occur.

[0135] (11-5)

[0136] Figure 6 or Fig.11 Each second row electrode 22 shown is configured to overlap with the second groove 36 at multiple locations in each detection area DA. As a result, in the stress sensor 1, compared with a case where the second row electrode 22 and the second groove 36 overlap at only one location, the overlapping location is arranged in a wider range, so that inter-axial interference is less likely to occur.

[0137] (11-6)

[0138] like Fig.10 As shown, the stress sensor 1 of the second embodiment has a silicon layer 71b on the surface of the stress detection sheet 8. The silicon layer 71b is an elastic layer that overlaps M×N (3×3 in the second embodiment) detection areas DA and has elasticity. As a result, in the stress sensor 1, stress is dispersed by the silicon layer 71b as an elastic layer, and inter-axial interference is less likely to occur.

[0139] (11-7)

[0140] like Fig.10 As shown, the stress sensor 1 of the second embodiment has a protective layer 81 on the back surface, and the protective layer 81 is composed of a silicon film overlapping with M×N (3×3 in the second embodiment) detection areas DA. As a result, in the stress sensor 1, the stress detection sheet 8 including the detection area DA does not slip due to the silicon film on the back surface, and the shear stress can be easily measured.

[0141] (12) Modification

[0142] (12-1) Modification A

[0143] In the above-mentioned embodiments, the first electrode layer 2 is composed of a conductive layer (for example, a layer formed by a layer of silver paste) including the first row electrodes 21 and the second row electrodes 22 and the first row wirings 23 and the second row wirings 24. However, the first row electrodes 21 and the second row electrodes 22 and the first row wirings 23 and the second row wirings 24 of the first electrode layer 2 may also be formed using a plurality of conductive layers. For example, the first row electrodes 21 and the second row electrodes 22 and the first row wirings 23 and the second row wirings 24 may also be formed in different conductive layers.

[0144] Furthermore, in each of the above-mentioned embodiments, the second electrode layer 3 is composed of a conductive layer (for example, a layer formed of a layer of silver paste) including the first column electrodes 31 and the second column electrodes 32 and the first column wirings 33 and the second column wirings 34. However, the first column electrodes 31 and the second column electrodes 32 and the first column wirings 33 and the second column wirings 34 of the second electrode layer 3 may also be formed using a plurality of conductive layers. For example, the first column electrodes 31 and the second column electrodes 32 and the first column wirings 33 and the second column wirings 34 may also be formed in different conductive layers.

[0145] (12-2) Modification B

[0146] In the above-mentioned embodiments, the case where the conductive layers of the first electrode layer 2 and the second electrode layer 3 are formed using a conductive paste (conductive adhesive) is described. However, these conductive layers may also be formed using other methods. For example, the conductive layers may also be formed by evaporating a metal film or etching a metal film.

[0147] (12-3) Modification C

[0148] In the above-mentioned embodiments, the stress detection sheet 8 is connected to the detection circuit 5. However, the stress detection sheet 8 may be configured to be detachable from the detection circuit 5. For example, the stress detection sheet 8 may be configured to be replaceable as a consumable.

[0149] In addition, the detection circuit 5 can also be configured to correspond to the number of wirings of the first row wiring 23, the second row wiring 24, the first column wiring 33, and the second column wiring 34, the number of electrodes of the first row electrode 21, the second row electrode 22, the first column electrode 31, and the second column electrode 32, or multiple types of stress detection sheets 8 with different configurations. For example, the detection circuit 5 can also be configured as follows: the detection circuit 5 includes a memory (not shown) so that the memory stores the number of wirings of each type of stress detection sheet 8, constants, and programs for detection, and performs stress detection according to different programs. By configuring the detection circuit 5 in a manner that can correspond to multiple types of stress detection sheets 8, it is possible to replace the appropriate stress detection sheet 8 that matches the shape and condition of the detection object to detect stress.

[0150] Description of Reference Numerals

[0151] 1: Stress sensor;

[0152] 2: first electrode layer;

[0153] 3: second electrode layer;

[0154] 4: Insulating elastomer layer;

[0155] 5: Detection circuit;

[0156] 8: Detection piece;

[0157] 21: first row of electrodes;

[0158] 21a: stress detection unit;

[0159] 22: second row of electrodes;

[0160] 23: First row wiring;

[0161] 24: Second row wiring;

[0162] 31: first column of electrodes;

[0163] 32: second column of electrodes;

[0164] 33: first column wiring;

[0165] 34: second column wiring;

[0166] 35: First slot;

[0167] 36: Second slot;

[0168] 71b: silicon layer;

[0169] 81: protective layer;

[0170] DA: Detection Area.

Claims

1. A stress sensor, comprising: The first electrode layer and the second electrode layer are arranged to overlap with M×N detection areas divided into M rows and N columns for detection, and the first electrode layer and the second electrode layer face each other, wherein: M and N are integers greater than 2; an insulating elastic layer, which is located between the first electrode layer and the second electrode layer, electrically insulates the two electrode layers, and is formed of an elastically deformable material; and a detection circuit connected to the first electrode layer and the second electrode layer, The first electrode layer includes: M pairs of first row electrodes and second row electrodes extending across N columns and insulated from each other; and M first row wirings and M second row wirings connecting the M pairs of the first row electrodes and the second row electrodes to the detection circuit. The second electrode layer includes: N pairs of first column electrodes and second column electrodes extending across M rows and insulated from each other; and N first column wirings and N second column wirings connecting N pairs of the first column electrodes and the second column electrodes to the detection circuit, In the second electrode layer, between each pair of the first column electrode and the second column electrode, there are M first grooves extending along a first direction in each row and M second grooves extending along a second direction intersecting the first direction. The first row electrodes in each pair are arranged to overlap with the first grooves of N columns, The second row electrodes in each pair are arranged to overlap the second grooves of N columns, The detection circuit is composed of: By driving the N pairs of the first column electrodes and the second column electrodes at different timings for each electrode, detecting a shear stress orthogonal to the first direction in the first grooves arranged in M ​​rows and N columns, detecting a shear stress orthogonal to the second direction in the second grooves arranged in M ​​rows and N columns, The pressing force in M ​​rows and N columns where M pairs of the first row electrodes and the second row electrodes intersect with N pairs of the first column electrodes and the second column electrodes is detected.

2. The stress sensor according to claim 1, wherein: The first row electrode and the second row electrode and the first row wiring and the second row wiring are formed by the same member arranged in the same plane. The first column electrode and the second column electrode and the first column wiring and the second column wiring are formed of the same member arranged in the same plane.

3. The stress sensor according to claim 1 or 2, wherein: In each of the first row electrodes, a connection portion between the stress detection portions adjacent to each other is thinner than a plurality of stress detection portions overlapping the first groove.

4. The stress sensor according to claim 1 or 2, wherein: Each of the first row electrodes is configured to overlap with the first groove at a plurality of locations in each detection region.

5. The stress sensor according to claim 1 or 2, wherein: Each of the second row electrodes is configured to overlap with the second groove at a plurality of locations in each detection region.

6. The stress sensor according to claim 1 or 2, wherein: An elastic layer having elasticity and overlapping with the M×N detection areas is provided on the surface.

7. The stress sensor according to claim 1 or 2, wherein: A silicon film overlapping the M×N detection regions is provided on the back surface.

8. A stress detection sheet, comprising: The first electrode layer and the second electrode layer are arranged to overlap with M×N detection areas divided into M rows and N columns for detection, and the first electrode layer and the second electrode layer face each other, wherein: M and N are integers greater than 2; as well as an insulating elastic layer, which is located between the first electrode layer and the second electrode layer, electrically insulates the two electrode layers, and is formed of an elastically deformable material, The first electrode layer comprises: M pairs of first row electrodes and second row electrodes extending across N columns and insulated from each other; and M first row wirings and M second row wirings for connecting M pairs of the first row electrodes and the second row electrodes to an off-chip circuit, The second electrode layer includes: N pairs of first column electrodes and second column electrodes extending across M rows and insulated from each other; and N first column wirings and N second column wirings for connecting the N pairs of the first column electrodes and the second column electrodes to an off-chip circuit, In the second electrode layer, between each pair of the first column electrode and the second column electrode, there are M first grooves extending along a first direction in each row and M second grooves extending along a second direction intersecting the first direction. The first row electrodes in each pair are arranged to overlap with the first grooves of N columns, The second row electrodes in each pair are arranged to overlap the second grooves of N columns.

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