Strain detection device

Abstract

The technical problem of the embodiment is to provide a strain detection device capable of improving detection accuracy. A strain detection device according to an embodiment is provided with: a sheet substrate; a plurality of strain gauges (22) arranged on the sheet substrate in a first direction; a plurality of power supply lines (VL) and a plurality of first signal lines (Sa) connected to one ends of the plurality of strain gauges, respectively; a plurality of ground lines (VNL) and a plurality of second signal lines (Sb) are respectively connected to the other ends of the plurality of strain gauges; and dummy patterns (D0, D1) provided on the sheet substrate and located in regions between the strain gauges adjacent to each other in the first direction.

Description

[0001] Citation of related applications such as priority basic application

[0002] This application is based on Japanese Patent Application No. 2023-106939 (filing date: June 29, 2023) and claims the priority benefit of that application. This application incorporates all the contents of that application by citing that application. Technical Field

[0003] Embodiments of the present invention relate to a strain sensing device. Background Art

[0004] As an example of a strain detection device, a film-shaped or sheet-shaped strain gauge sensor is known. The strain gauge sensor includes: a plurality of strain gauges arranged on the surface of a strip-shaped flexible sheet substrate; and a plurality of signal lines for energizing the strain gauges. By wrapping the strain gauge sensor around a bent object to be inspected and detecting the resistance change of each strain gauge, the bent shape of the object to be inspected can be detected.

[0005] In this strain gauge sensor, multiple strain gauges are arranged at intervals. Therefore, in the sheet substrate, the elastic modulus of the portion with the strain gauge and the portion without the strain gauge are different, and the portion with a high elastic modulus is difficult to bend, while the portion with a low elastic modulus is easy to bend. Therefore, when the strain gauge sensor is bent, stress may be concentrated on the portion without the strain gauge, resulting in uneven shape. In this case, high-precision strain detection becomes difficult. Summary of the invention

[0006] An object of an embodiment of the present invention is to provide a strain detection device capable of improving detection accuracy.

[0007] The strain detection device involved in the embodiment comprises: a sheet substrate; a plurality of strain gauges arranged on the sheet substrate in a first direction; a plurality of power lines and a plurality of first signal lines, respectively connected to one end of the plurality of strain gauges; a plurality of ground lines and a plurality of second signal lines, respectively connected to the other end of the plurality of strain gauges; and a dummy pattern, arranged on the sheet substrate and located in an area between the strain gauges adjacent to each other in the first direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a perspective view of the strain gauge sensor device according to the first embodiment.

[0009] Figure 2 is a top view showing a portion of a sensor sheet of the strain gauge sensor device.

[0010] Figure 3 is a block diagram showing a sensor sheet and a controller of the strain gauge sensor device.

[0011] Figure 4 is a side view of the sensor sheet in a bent state.

[0012] Figure 5A It is a plan view showing a part of the sensor sheet according to the first modification.

[0013] Figure 5B It is a plan view showing a part of the sensor sheet according to the second modification.

[0014] Figure 6 It is a plan view showing a part of the sensor sheet according to the third modification.

[0015] Figure 7 It is a plan view showing a part of the sensor sheet of the strain gauge sensor device according to the second embodiment.

[0016] Figure 8 It is a plan view showing a part of a sensor sheet of a strain gauge sensor device according to a third embodiment.

[0017] Fig. 9 It is a perspective view of a strain gauge sensor device according to a fourth embodiment.

[0018] Fig.10 It is a cross-sectional view of a strain gauge sensor device according to a fourth embodiment.

[0019] Fig.11 This is an exploded perspective view showing a sensor sheet and a part of a base substrate of a strain gauge sensor device according to a fourth embodiment in an exploded manner. DETAILED DESCRIPTION

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0021] Please note that the disclosure is only an example, and appropriate changes that can be easily thought of by those skilled in the art while maintaining the main purpose of the invention are certainly included in the scope of the present invention. In addition, in order to make the description clearer, the drawings sometimes schematically indicate the width, thickness, shape, etc. of each part compared to the actual method, but it is only an example after all, and is not a restrictive interpretation of the present invention. In addition, in this specification and each figure, the same elements as those described in the drawings that have appeared are marked with the same figure numbers, and the detailed description is sometimes appropriately omitted.

[0022] (First Embodiment)

[0023] As an example of a strain detection device, a strain gauge sensor device according to the embodiment will be described in detail. Figure 1 It is a perspective view of the strain gauge sensor device according to the first embodiment.

[0024] As shown in the figure, according to the first embodiment, the strain gauge sensor device 10 constitutes a single-sided strain gauge sensor. The strain gauge sensor device 10 includes a flexible base substrate 44 in the form of an elongated strip that functions as a substrate, a sensor sheet 20 attached to a single surface of the base substrate 44, and a relay substrate (driving circuit substrate) 12 connected to the sensor sheet 20 via a flexible wiring board (FPC) 14. In one example, the base substrate 44 is formed of a resin such as polyethylene terephthalate (PET) or polyimide to a thickness of about 0.3 to 0.5 mm.

[0025] Note that in the figure, the length direction X and the width direction Y of the base substrate 44 and the sensor sheet 20 represent two directions that are orthogonal to each other. These directions may intersect at an angle other than 90 degrees.

[0026] The sensor sheet 20 has a flexible sheet substrate 22 in the shape of an elongated strip and a conductor pattern provided on one side of one surface of the sheet substrate 22. The conductor pattern includes a plurality of strain gauges G0 to Gn and a plurality of signal lines and power lines described later. The plurality of strain gauges G0 to Gn are arranged in a row with a predetermined interval in the longitudinal direction X from one end to the other end of the sheet substrate 22. The surface of the sensor sheet 20 having the conductor pattern (G0 to Gn) is adhered to the front surface of the base substrate 44 via an adhesive layer such as a transparent adhesive sheet (OCA). Alternatively, the sensor sheet 20 may also have a structure in which one side of the sheet substrate 22 is adhered to the front surface of the base substrate 44 via an adhesive layer.

[0027] The relay substrate 12 includes a drive circuit 40 and a plurality of wirings, which will be described later. The conductor pattern of the sensor sheet 20 is connected to the wirings of the relay substrate 12 via the FPC 14 .

[0028] Figure 2 is a top view showing a portion of the sensor sheet 20, Figure 3 1 is a diagram schematically showing a strain gauge and a wiring pattern of the sensor sheet 20 and a controller of the strain gauge sensor device 10 .

[0029] As shown in the figure, according to this embodiment, the sensor sheet 20 has a flexible strip-shaped sheet substrate 22 and a conductor pattern provided on one side of the sheet substrate 22. The conductor pattern is a wiring pattern formed of a conductive metal such as aluminum, titanium, copper, etc., and includes a plurality of strain gauges G0 to Gn, a plurality of dummy patterns D0 to Dn, and a plurality of wirings. In one example, each wiring pattern is set as a pattern of a certain width.

[0030] like Figure 2As shown, a plurality of strain gauges G0 to Gn are arranged in a row with intervals in the longitudinal direction X from one end (front end) to the other end (base end) in the longitudinal direction X of the sheet substrate 22. Each of the strain gauges G0 to Gn extends in a corrugated shape in the width direction Y, and has one end and the other end in the width direction Y. According to the present embodiment, each of the strain gauges G0 to Gn has a base line B1 extending in the width direction Y and having one end and the other end in the width direction Y; and a plurality of, for example, four, waveform lines C1 to C4 extending from the base line B1 in one direction in the longitudinal direction X. In one example, the four waveform lines C1 to C4 are formed in a rectangular wave shape, and the height in the longitudinal direction X is formed to be a common height. The four waveform lines C1 to C4 are arranged with intervals in the width direction Y. The four waveform lines C1 to C4 are located within the range of the width W1 in the width direction Y. Each of the strain gauges G0 to Gn generates a resistance change corresponding to the strain.

[0031] A plurality of dummy patterns D0 to Dn are respectively arranged in the region between two adjacent strain gauges in the length direction X. In one example, each of the dummy patterns D0 to Dn includes a plurality of, for example, eight dummy lines d1 to d8 formed in a straight line. The eight dummy lines d1 to d8 extend in the length direction X, respectively, and are arranged at intervals in the width direction Y. The eight dummy lines d1 to d8 are arranged within the range of the width W1, and are respectively aligned with the waveform lines C1 to C4 of the strain gauge in the length direction X. Each of the dummy lines d1 to d8 has one end in the length direction X located near one strain gauge, and the other end in the length direction X located near another strain gauge.

[0032] By providing the dummy patterns D0 to Dn in the region between two adjacent strain gauges in this manner, in the sensor sheet 20 , the elastic modulus of the region where the strain gauges G0 to Gn are provided is made substantially equal to the elastic modulus of the gap region where no strain gauge is provided.

[0033] like Figure 2 and Figure 3 As shown, the conductor pattern includes a plurality of power lines VL0 to VLn, a plurality of ground lines GNL0 to GNLn, a plurality of first signal lines Sa0 to San, and a plurality of second signal lines Sb0 to Sbn extending in the longitudinal direction X along the columns of the strain gauges G0 to Gn.

[0034] The power supply lines VL0 to VLn are located on one end side of the strain gauges G0 to Gn. The power supply lines VL0 to VLn have one end connected to one end of the strain gauges G0 to Gn and the other end located on the base end side of the sheet base 22, and extend substantially parallel to each other.

[0035] The first signal lines Sa0 to San are located between one end of the strain gauges G0 to Gn and the power lines VL0 to VLn. The first signal lines Sa0 to San have one end connected to one end of the strain gauges G0 to Gn and the other end located on the base end side of the sheet base 22, and extend substantially parallel to each other.

[0036] The grounding wires GNL0 to GNLn are located on the other end side of the strain gauges G0 to Gn. The grounding wires GNL0 to GNLn have one end connected to the other end of the strain gauges G0 to Gn and the other end located on the base end side of the sheet base 22, and extend substantially parallel to each other.

[0037] The second signal lines Sb0 to Sbn are located between the other ends of the strain gauges G0 to Gn and the ground lines GNL0 to GNLn. The second signal lines Sb0 to Sbn have one end connected to the other ends of the strain gauges G0 to Gn and the other end located on the base end side of the sheet base 22, and extend substantially parallel to each other.

[0038] The power supply lines VL0 to VLn, the first signal lines Sa0 to San, the second signal lines Sb0 to Sbn, and the ground lines GNL0 to GNLn are connected to the drive circuit 40 of the relay substrate 12 via the FPC 14 .

[0039] Note that the metal layer in which the strain gauges G0 to Gn, the dummy patterns D0 to Dn, the power lines VL0 to VLn, and the ground lines GNL0 to GNLn are formed on the sensor sheet 20 and the metal layer in which the first signal lines Sa0 to San and the second signal lines Sb0 to Sbn are formed are formed by different layers. An insulating intermediate layer is provided between the two metal layers, and the first signal lines Sa0 to San and the second signal lines Sb0 to Sbn are connected to the power lines VL0 to VLn and the ground lines GNL0 to GNLn via through holes formed in the intermediate layer. Note that either or both of the strain gauges G0 to Gn and the dummy patterns D0 to Dn may be formed by a metal layer different from the metal layer in which the power lines VL0 to VLn and the ground lines GNL0 to GNLn are formed.

[0040] Next, a driving circuit (controller) for driving the sensor sheet 20 configured as described above will be described.

[0041] like Figure 3 As shown, the drive circuit 40 provided on the relay substrate (control circuit substrate) 12 includes a selector SEL, an analog front end (AFE: signal adjustment circuit) 30 , a timing controller 34 , a communication interface 36 , and the like.

[0042] The communication interface 36 is connected to an external host controller 38 wirelessly or by wire, receives a driving signal (setting) from the host controller 38 , and sends detection data (Data) to the host controller 38 .

[0043] The timing controller 34 outputs a driving signal to the selector SEL and the analog front end 30 according to a driving signal (setting).

[0044] The selector SEL is composed of a plurality of shift registers, multiplexers, etc. The selector SEL sequentially connects the power supply lines VL0 to VLn of the sensor sheet 20 to the power supply according to the drive signal from the timing controller 34, and sequentially applies voltage to the strain gauges G0 to Gn. In synchronization with this, the selector SEL sequentially reads the detection signals (voltage values) RXa0 to RXan and RXb0 to RXbn of one end side and the other end side of each strain gauge G0 to Gn via the first signal lines Sa0 to San and the second signal lines Sb0 to Sbn.

[0045] like Figure 3 As shown, the analog front end 30 includes a readout circuit, a differential detection circuit, an AD converter, a digital filter, a memory, etc. (not shown). The analog front end 30 performs signal conditioning (amplification, AD conversion, filtering) on ​​the detection signals RXa, RXb and the detection signals RXc, RXd of the strain gauges G0 to Gn sent from the selector SEL according to the drive signal, and outputs them to the communication interface 36. At this time, in order to calculate the radius of curvature, the voltage drop value of each strain gauge G is required, so the difference of the detection values ​​Rxa, Rxb of each strain gauge G0 to Gn and the difference of the detection values ​​Rxc, Rxd of the strain gauges G0 to Gn are obtained by the differential detection circuit, and the signal is output.

[0046] The host controller 38 includes a reading circuit 38a, a memory 38b, an operation processing unit 38c, etc. The reading circuit 38a reads the output signal (differential data) sent from the communication interface 36 and stores it in the memory 38b. The operation processing unit 38c, such as a CPU, performs operation processing such as data shaping and surface calculation based on the differential data to calculate the strain (curvature radius), surface shape (surface coordinates), etc. of the object to be inspected detected by the sensor sheet 20. The differential data, the calculated curvature radius, the surface shape, the detection action program, etc. are stored in the memory 38b.

[0047] Figure 4 1 is a side view showing a state in which the sensor piece 20 of the strain gauge sensor device 10 configured as described above is bent.

[0048] According to the sensor sheet 20 of the above configuration, by providing dummy patterns D0 to Dn in the region between two adjacent strain gauges in the length direction X, the elastic modulus of the region where the strain gauges G0 to Gn are provided and the elastic modulus of the gap region where the strain gauges are not provided can be made substantially equal. That is, the elastic modulus of each region in the length direction X of the sensor sheet 20 can be made uniform. Therefore, Figure 4 As shown, when the sensor piece 20 is bent, stress does not concentrate on a part of the sensor piece 20, and the entire region in the longitudinal direction can be bent uniformly. That is, the region where the strain gauges G0 to Gn are provided can be bent uniformly.

[0049] Therefore, for example, when the sensor sheet 20 is wound around the outer surface of the object to be inspected to detect the strain of the outer surface, the detection of the curvature radius, etc., each strain gauge G0 to Gn can be bent along the outer surface and closely adhere to the outer surface. As a result, the strain of the outer surface can be detected more accurately, and the detection accuracy can be improved.

[0050] As described above, according to the present embodiment, a strain gauge sensor device with improved detection accuracy can be obtained.

[0051] Note that in the first embodiment described above, the dummy pattern D of the sensor sheet 20 is not limited to the embodiment, and various modifications may be made. The following describes a modification of the dummy pattern D. In the modification described below, the same reference numerals as those in the first embodiment are used for the same parts as those in the first embodiment, and the detailed description thereof may be simplified or omitted.

[0052] (First Modification)

[0053] Figure 5A 1 is a top view showing a portion of a sensor sheet according to a first modification. As shown in the figure, according to the first modification, each of the dummy patterns D0 to Dn includes a plurality of, for example, eight dummy lines d1 to d8 formed in a straight line. The eight dummy lines d1 to d8 extend in the length direction X and are arranged at intervals in the width direction Y. The eight dummy lines d1 to d8 are arranged within a width W1 and are aligned with the waveform lines C1 to C4 of the strain gauge in the length direction X.

[0054] In the first variant, one end of multiple, for example, four, of the eight imaginary lines d1 to d8 is connected to the waveform line of one of the two adjacent strain gauges. One end of the other four imaginary lines is connected to the waveform line of the other strain gauge. In one example, the imaginary lines (first lines) d1, d3, d5, and d7 are connected to the waveform lines C1, C2, C3, and C4 of one strain gauge G1, and the imaginary lines (second lines) d2, d4, d6, and d8 are connected to the waveform lines C1, C2, C3, and C4 of another strain gauge G2. As a result, the imaginary lines d1 to d8 are arranged in a so-called nested manner.

[0055] In the first modification, the other configurations of the sensor sheet 20 are the same as those of the sensor sheet 20 in the first embodiment.

[0056] The sensor sheet 20 involved in the first modification can also obtain the same effects as those of the first embodiment. In addition, in the first modification, by configuring a plurality of dummy lines in the gap regions between the dummy patterns D0 to Dn and the strain gauges G0 to Gn, the elastic modulus of each gap region can be increased. Thus, the elastic modulus of each part of the sensor sheet 20 can be further unified.

[0057] (Second Modification)

[0058] Figure 5B 1 is a top view showing a portion of a sensor sheet according to a second modification. As shown in the figure, according to the second modification, each of the dummy patterns D0 to Dn includes a plurality of, for example, eight, dummy lines d1 to d8 arranged in the same manner as in the first modification described above. Furthermore, in the second modification, each of the dummy lines d1 to d8 is broken at one point in the longitudinal direction X and is divided into two lines. The broken portions of the dummy lines d1 to d8 are located at positions offset from each other in the longitudinal direction X in a manner that is not aligned in the width direction Y.

[0059] In the second modification, the other configurations of the sensor sheet 20 are the same as those of the sensor sheet 20 in the first modification.

[0060] The sensor sheet 20 according to the second modification can also achieve the same effects as those of the first modification. Furthermore, in the second modification, the parasitic capacitance can be reduced by disconnecting the dummy lines. Note that the number of disconnected dummy lines is not limited to two, but may be three or more.

[0061] (Third Modification)

[0062] Figure 6: is a top view showing a portion of the sensor sheet involved in the third modification. As shown in the figure, according to the third modification, each of the strain gauges G0~Gn and the dummy patterns D0~Dn are formed into a random pattern. In detail, each of the strain gauges G0~Gn has a baseline B1 extending in the width direction Y, a plurality of waveform lines C1, C3, C4 extending from the baseline B1 in one direction of the length direction X, and a plurality of waveform lines C2, C5, C6 extending from the baseline B1 in the opposite direction opposite to the one direction of the length direction X. In one example, the waveform lines C1, C3, C4 have a rectangular wave shape and are formed to have different extension heights with respect to the baseline B1. The waveform lines C2, C5, C6 have a rectangular wave shape and are formed to have different extension heights with respect to the baseline B1.

[0063] Each of the dummy patterns D0 to Dn includes a plurality of, for example, nine, dummy lines d1 to d9 formed in a straight line shape. The nine dummy lines d1 to d9 extend in the length direction X and are arranged at intervals in the width direction Y. The nine dummy lines d1 to d9 are aligned with the waveform lines C1 to C6 of the strain gauge in the length direction X.

[0064] Many of the nine imaginary lines d1 to d9, for example, imaginary lines d1 and d9 located at both ends in the width direction Y, have one end in the length direction X connected to the waveform line of the strain gauge G1 or G2, and the other end in the length direction X faces the waveform line of the strain gauge G2 or G1 with a small gap. The other seven imaginary lines d2 to d8 each have one end in the length direction X facing the waveform line of the strain gauge G1 with a small gap, and the other end in the length direction X faces the waveform line of the strain gauge G2 with a small gap.

[0065] The gaps between one ends of the nine imaginary lines d1 to d9 and the strain gauge G1 are not aligned in the width direction Y but are offset in the length direction X. Similarly, the gaps between the other ends of the nine imaginary lines d1 to d9 and the strain gauge G2 are not aligned in the width direction Y but are offset in the length direction X.

[0066] Each of the nine dummy lines d1 to d9 is broken in the middle of the longitudinal direction X and divided into two or three lines. The broken portions of the dummy lines d1 to d9 are not aligned in the width direction Y but are offset in the longitudinal direction X.

[0067] Furthermore, regarding the broken lines located in the middle part of the nine virtual lines d1 to d9 in the length direction X, the ends of the adjacent broken lines in the width direction Y are connected to each other by a connecting line extending in the width direction Y, forming a wavy virtual line dw that extends continuously in a wavy manner.

[0068] In the third modification, the other configurations of the sensor sheet 20 are the same as those of the sensor sheet 20 of the first embodiment. The sensor sheet 20 of the third modification can also achieve the same effects as those of the first and second modifications. Furthermore, in the third modification, the elastic modulus of the sensor sheet 20 can be further uniformed by making the strain gauges and the imaginary lines more randomly arranged.

[0069] Next, strain gauge sensor devices according to other embodiments of the present invention will be described. In the other embodiments described below, the same reference numerals as those in the first embodiment are used to denote the same components as those in the first embodiment, and detailed description thereof may be simplified or omitted.

[0070] (Second Embodiment)

[0071] Figure 7 1 is a top view showing a portion of a sensor sheet in a strain gauge sensor device according to a second embodiment. In the second embodiment, the imaginary lines are omitted, and instead, the waveform lines of adjacent strain gauges are arranged in a nested manner so that the regions between adjacent strain gauges are filled with the waveform lines.

[0072] In detail, Figure 7 As shown, the strain gauges G0 to Gn are arranged in the longitudinal direction X of the sensor sheet 20. Each of the strain gauges G0 to Gn has a base line B1 extending in the width direction Y, a plurality of, for example, two, waveform lines (first waveform lines) C1 and C3 extending from the base line B1 in one direction of the longitudinal direction X, and a plurality of, for example, two, waveform lines (second waveform lines) C2 and C4 extending from the base line B1 in the opposite direction opposite to the one direction of the longitudinal direction X. In one example, the waveform lines C1 to C4 have a rectangular wave shape.

[0073] The waveform lines C1 and C3 are located at intervals corresponding to one waveform line in the width direction Y. In addition, the waveform lines C1 and C3 extend in the longitudinal direction X from the base line B1 of the strain gauge G1 to the vicinity of the base line B1 of the adjacent strain gauge G2.

[0074] The waveform lines C2 and C4 are located at intervals corresponding to one waveform line in the width direction Y. In addition, the waveform lines C2 and C4 extend from the baseline B1 of one strain gauge G2 to the vicinity of the baseline B1 of the adjacent strain gauge G1 in the length direction X, and are arranged in a nested manner with respect to the waveform lines C1 and C3 of the adjacent strain gauge G1. That is, the waveform lines C1 and C3 of one strain gauge and the waveform lines C2 and C4 of the other strain gauge are arranged in the width direction Y and are provided in the area between the adjacent strain gauges, in this case, the area between the baseline B1 of one strain gauge and the baseline B1 of the other strain gauge.

[0075] As described above, according to the second embodiment, the strain gauges G0 to Gn are provided over the entire area of ​​the sheet base 22 in the longitudinal direction X. Therefore, the elastic modulus of the sensor sheet 20 can be made uniform over almost the entire area in the longitudinal direction X of the sensor sheet 20 .

[0076] In the second embodiment, the other configurations of the strain gauge sensor device are the same as those of the strain gauge sensor device in the first embodiment. In the second embodiment as well, a strain gauge sensor device with improved detection accuracy can be obtained.

[0077] (Third Embodiment)

[0078] Figure 8 1 is a top view showing a portion of a sensor sheet in a strain gauge sensor device according to a third embodiment. In the third embodiment, a sensor sheet 20 of the strain gauge sensor device has dummy wiring patterns E0 to En in addition to dummy patterns D0 to Dn. The dummy wiring patterns E0 to En are provided in a region of the sensor sheet 20 overlapping a region where strain gauges G0 to Gn and power lines, ground lines, and signal lines are not provided.

[0079] In detail, Figure 8 As shown, the sensor sheet 20 has a sheet substrate 22 and a conductor pattern formed on one surface of the sheet substrate. The conductor pattern is a wiring pattern of a certain width formed of a conductive metal such as aluminum, titanium, copper, etc., and includes a plurality of strain gauges G0 to Gn, a plurality of dummy patterns D0 to Dn, a plurality of wirings, and a plurality of dummy wiring patterns E0 to En.

[0080] A plurality of strain gauges G0 to Gn are arranged in a row with intervals in the longitudinal direction X from one end (front end) to the other end (base end) of the sheet substrate 22 in the longitudinal direction X. Each of the strain gauges G0 to Gn has a base line B1 extending in the width direction Y and having one end and the other end in the width direction Y, and a plurality of, for example, four, wavy lines C1 to C4 extending from the base line B1 in one direction in the longitudinal direction X. The four wavy lines C1 to C4 are arranged with intervals in the width direction Y. The four wavy lines C1 to C4 are located within the range of the width W1 in the width direction Y.

[0081] A plurality of dummy patterns D0 to Dn are respectively arranged in the region between two adjacent strain gauges in the length direction X. In one example, each of the dummy patterns D0 to Dn includes a plurality of, for example, eight dummy lines d1 to d8 formed in a straight line. The eight dummy lines d1 to d8 extend in the length direction X, respectively, and are arranged at intervals in the width direction Y. The eight dummy lines d1 to d8 are arranged within the range of the width W1, and are respectively aligned with the waveform lines C1 to C4 of the strain gauge in the length direction X. Each of the dummy lines d1 to d8 has one end in the length direction X located near one strain gauge, and the other end in the length direction X located near another strain gauge.

[0082] The plurality of wirings include a plurality of power supply lines VL0 to VLn, a plurality of ground lines GNL0 to GNLn, a plurality of first signal lines Sa0 to San, and a plurality of second signal lines Sb0 to Sbn extending in the longitudinal direction X along the columns of the strain gauges G0 to Gn.

[0083] The power supply lines VL0 to VLn are located on one end side of the strain gauges G0 to Gn. The power supply lines VL0 to VLn have one end connected to one end of the strain gauges G0 to Gn and the other end located on the base end side of the sheet base 22, and extend substantially parallel to each other.

[0084] The first signal lines Sa0 to San are located between one end of the strain gauges G0 to Gn and the power lines VL0 to VLn. The first signal lines Sa0 to San have one end connected to one end of the strain gauges G0 to Gn and the other end located on the base end side of the sheet substrate 22, respectively, and extend substantially parallel to each other. The power lines VL0 to VLn and the first signal lines Sa0 to San are arranged within the range of the area of ​​the width W2 of the sheet substrate 22.

[0085] The grounding wires GNL0 to GNLn are located on the other end side of the strain gauges G0 to Gn. The grounding wires GNL0 to GNLn have one end connected to the other end of the strain gauges G0 to Gn and the other end located on the base end side of the sheet base 22, and extend substantially parallel to each other.

[0086] The second signal lines Sb0 to Sbn are located between the other ends of the strain gauges G0 to Gn and the ground lines GNL0 to GNLn. The second signal lines Sb0 to Sbn have one end connected to the other ends of the strain gauges G0 to Gn and the other end located on the base end side of the sheet substrate 22, respectively, and extend substantially parallel to each other. The ground lines GNL0 to GNLn are arranged within the range of the width W2 of the sheet substrate 22.

[0087] A plurality of dummy wiring patterns E0 to En are provided in an area of ​​the sensor sheet 20 where the strain gauges G0 to Gn, the power lines VL0 to VLn, the ground lines GNL0 to GNLn, the first signal lines Sa0 to San, and the second signal lines Sb0 to Sbn are not provided. In one example, each of the dummy wiring patterns E0 to En includes one or more dummy wirings formed in a straight line.

[0088] In detail, the dummy wiring pattern E0 includes, for example, eight dummy wirings e1 to e8. Among the eight dummy wirings e1 to e8, four dummy wirings e1 to e4 are arranged in a region on one side in the width direction Y of the strain gauge G0. The four dummy wirings e1 to e4 extend in the length direction X, respectively, and are arranged in parallel with intervals in the width direction Y. The four dummy wirings e1 to e4 are arranged within the range of the width W2, and each has a length (height) substantially the same as the waveform lines C1 to C4 of the strain gauge G0. The dummy wirings e1 and e3 are aligned with the power line VL0 and the first signal line Sa0 in the length direction X, respectively.

[0089] The other four dummy wirings e5 to e8 are arranged in the area on the other side of the strain gauge G0 in the width direction Y. The four dummy wirings e5 to e8 extend in the length direction X, respectively, and are arranged in parallel with a gap in the width direction Y. The four dummy wirings e5 to e8 are arranged within the width W2, and each has a length (height) substantially the same as the waveform lines C1 to C4 of the strain gauge G0. The dummy wirings e6 and e8 are aligned with the second signal line Sb0 and the ground line GNL1 in the length direction X, respectively.

[0090] The dummy wiring pattern E1 includes, for example, four dummy wirings e1 to e4. The dummy wiring e1 is arranged in the region between the power line VL0 and the first signal line Sa0, and extends from the vicinity of the baseline of the strain gauge G0 to the vicinity of the baseline of the strain gauge G1 in the length direction X. The dummy wiring e2 is arranged in the region between the dummy pattern D0, the strain gauge G1, and the first signal line Sa0, and extends from the vicinity of the baseline of the strain gauge G0 to the vicinity of the baseline of the strain gauge G1 in the length direction X. The dummy wirings e1 and e2 are respectively aligned with the power line VL1 and the first signal line Sa1 in the length direction X, and further, are respectively aligned with the dummy wirings e2 and e4 of the dummy wiring pattern E0 in the length direction X.

[0091] The dummy wiring e3 of the dummy wiring pattern E1 is arranged in the region between the dummy pattern D0 and the strain gauge G1 and the second signal line Sb0, and extends from the vicinity of the baseline of the strain gauge G0 to the vicinity of the baseline of the strain gauge G1 in the length direction X. The dummy wiring e4 is arranged in the region between the ground line GNL0 and the second signal line Sb0, and extends from the vicinity of the baseline of the strain gauge G0 to the vicinity of the baseline of the strain gauge G1 in the length direction X. The dummy wirings e3 and e4 are respectively aligned with the second signal line Sb1 and the ground line GNL1 in the length direction X, and further, are respectively aligned with the dummy wirings e5 and e7 of the dummy wiring pattern E0 in the length direction X.

[0092] In the third embodiment, the other structures of the strain gauge sensor device are the same as those of the strain gauge sensor device in the first embodiment. According to the third embodiment configured as described above, by providing dummy patterns D0 to Dn in the region between two adjacent strain gauges, the elastic modulus of the region where the strain gauges G0 to Gn are provided in the sensor sheet 20 can be made substantially equal to the elastic modulus of the gap region where the strain gauges are not provided. Furthermore, by providing dummy wiring patterns E0 to En in the region where the strain gauges G0 to Gn and the power supply line, ground line, and signal line are not provided, the elastic modulus of the region where the wiring is provided in the sensor sheet 20 can be made substantially equal to the elastic modulus of the region where the wiring is not provided. As a result, the elastic modulus of the sensor sheet 20 can be made more uniform in almost the entire region in the longitudinal direction X of the sensor sheet 20.

[0093] As described above, also in the third embodiment, a strain gauge sensor device with improved detection accuracy can be obtained.

[0094] Note that in the third embodiment, the dummy patterns D0 to Dn are not limited to those shown in the embodiment, and the dummy patterns D0 to Dn shown in the first to third modified examples may also be used. Furthermore, the dummy wiring patterns E0 to En shown in the third embodiment may also be applied to the sensor sheet shown in the second embodiment.

[0095] (Fourth Embodiment)

[0096] Fig. 9 is a perspective view of a strain gauge sensor device according to a fourth embodiment. Fig.10 is a cross-sectional view of a strain gauge sensor device.

[0097] like Fig. 9As shown in FIG. 1 , the strain gauge sensor device 10 according to the fourth embodiment is a double-sided strain gauge sensor. The strain gauge sensor device 10 includes a flexible base substrate 44 in the form of an elongated strip, a first sensor sheet 20A adhered to the first main surface (front surface) of the base substrate 44, a second sensor sheet 20B adhered to the second main surface (back surface) of the base substrate 44, and a relay substrate (driving circuit substrate) 12 connected to the first sensor sheet 20A and the second sensor sheet 20B via a flexible wiring board (FPC) 14. In one example, the base substrate 44 is formed of a resin such as polyethylene terephthalate (PET) or polyimide to a thickness of about 0.3 to 0.5 mm.

[0098] Each of the first sensor sheet 20A and the second sensor sheet 20B includes a flexible sheet substrate 22 in the shape of an elongated strip and a conductor pattern provided on one side of one surface of the sheet substrate 22. The conductor pattern includes a plurality of strain gauges G0 to Gn and a plurality of dummy patterns D0 to Dn. The plurality of strain gauges G1 to Gn are arranged in a row with a predetermined interval in the longitudinal direction X from one end to the other end of the sheet substrate 22. As described later, the conductor pattern of the first sensor sheet 20A and the second sensor sheet 20B is formed, for example, as the same conductor pattern as in the first modification example described above.

[0099] Fig.10 It is a longitudinal sectional view of a strain gauge sensor device 10 according to a fourth embodiment.

[0100] like Fig.10 As shown, the base substrate 44 has a front surface and a back surface opposite to the front surface. In one example, the surface of the first sensor sheet 20A having the conductor pattern (G1 to Gn, D0 to Dn) is adhered to the front surface of the base substrate 44 through an adhesive layer Ad such as a transparent adhesive sheet (OCA). The surface of the second sensor sheet 20B having the conductor pattern (G1 to Gn, D0 to Dn) is adhered to the back surface of the base substrate 44 through an adhesive layer Ad.

[0101] The relay substrate 12 includes a driving circuit 40 and a plurality of wirings provided on one surface side and a plurality of wirings (not shown) provided on the other surface side. The strain gauge of the first sensor sheet 20A and the wirings (not shown) are connected to the wirings provided on the upper surface side of the relay substrate 12 via the FPC 14. Similarly, the strain gauge of the second sensor sheet 20B and the wirings (not shown) are connected to the wirings provided on the lower surface side of the relay substrate 12 via the FPC 14.

[0102] Part of the wiring of the first sensor sheet 20A and the second sensor sheet 20B may be connected to each other through connection lines such as plated through holes SH provided on the relay substrate 12. In addition, the first sensor sheet 20A and the second sensor sheet 20B may be configured such that one side of the sheet base material 22 is adhered to the front and back surfaces of the base substrate 44 via adhesive layers Ad.

[0103] Fig.11 It is a disassembled stereoscopic view showing a portion of the first and second sensor sheets and the base substrate. As shown in the figure, the first sensor sheet 20A has a sheet substrate 22 and a conductor pattern provided on the sheet substrate 22. In one example, the conductor pattern is formed in the same manner as the conductor pattern shown in the first variant example, and includes strain gauges G0 to Gn, dummy patterns D0 to Dn, and a wiring pattern not shown. The second sensor sheet 20B is constructed in the same manner as the first sensor sheet 20A, and has the same conductor pattern (G0 to Gn, D0 to Dn, wiring pattern). The conductor pattern of the second sensor sheet 20B is formed by a pattern that is flipped 180 degrees in the XY direction relative to the conductor pattern of the first sensor sheet 20A. The second sensor sheet 20B is opposite to the first sensor sheet 20A in an orientation that is rotated 180 degrees in the Z direction relative to the first sensor sheet 20A. That is, as Fig.11 As shown, the back surfaces of the first sensor sheet 20A and the second sensor sheet 20B face each other, but when viewed from the first sensor sheet 20A side, the pattern of the first sensor sheet 20A coincides with the pattern of the second sensor sheet.

[0104] The first sensor sheet 20A and the second sensor sheet 20B configured as described above are attached to the front and back surfaces of the base substrate 44, and face each other via the base substrate 44. That is, the strain gauges G0 to Gn, the dummy patterns D0 to Dn, and the wiring of the first sensor sheet 20A face the strain gauges G0 to Gn, the dummy patterns D0 to Dn, and the wiring of the second sensor sheet 20B via the base substrate 44. Here, it is preferable that the strain gauges G0 to Gn, the dummy patterns D0 to Dn, and the wiring of the first sensor sheet and the strain gauges G0 to Gn, the dummy patterns D0 to Dn, and the wiring of the second sensor sheet at least partially overlap each other when viewed from a plan view in a direction perpendicular to the surface of the base substrate 44. Alternatively, it is preferable that the strain gauges G0 to Gn, the dummy patterns D0 to Dn, and the wiring of the sensor sheets 20A and 20B overlap each other while allowing at least a shift in the longitudinal direction X but not shifting in the width direction Y. Alternatively, the strain gauges G0 to Gn, the dummy patterns D0 to Dn, and the wirings of the sensor sheets 20A and 20B are preferably overlapped without being shifted in both the longitudinal direction X and the width direction Y.

[0105] In the double-sided strain gauge sensor device 10 according to the fourth embodiment configured as described above, the same effects as those of the strain gauge sensor device according to the first embodiment can be obtained. That is, in the fourth embodiment, the strain gauges of the sensor sheet can be bent uniformly along the peripheral surface of the object to be inspected and can be closely attached to the peripheral surface when detecting strain. Thus, the strain of the peripheral surface can be more accurately detected by each strain gauge, and a strain gauge sensor device capable of improving detection accuracy can be obtained.

[0106] Note that in the fourth embodiment, the configuration of each sensor sheet is not limited to the illustrated example, and the sensor sheets shown in the first embodiment, the second modification example, the third modification example, the second embodiment, and the third embodiment may also be applied.

[0107] The embodiments and variations of the present invention have been described, but these embodiments and variations are presented as examples and are not intended to limit the scope of the invention. The new embodiments can be implemented in various other ways, and various omissions, substitutions, changes, and combinations can be made without departing from the scope of the invention. The embodiments and variations thereof are included in the scope and spirit of the invention, and are also included in the invention described in the claims and the scope of their equivalents.

[0108] All structures that can be implemented by those skilled in the art by appropriately changing the design of each structure described above as an embodiment of the present invention also belong to the scope of the present invention as long as they include the gist of the present invention.

[0109] For example, the number of strain gauges arranged in the sensor sheet is not limited to the above-described embodiment, and can be arbitrarily selected. The constituent material, size, and shape of the sensor sheet are not limited to the above-described embodiment, and can be appropriately modified.

Claims

1. A strain detection device, comprising: Sheet substrate; A plurality of strain gauges are arranged on the sheet substrate in a first direction; A plurality of power lines and a plurality of first signal lines, connected to one end of the plurality of strain gauges respectively; a plurality of ground wires and a plurality of second signal wires, respectively connected to the other ends of the plurality of strain gauges; as well as The dummy pattern is disposed on the sheet substrate and is located between two strain gauges of the plurality of strain gauges adjacent to each other.

2. The strain detection device according to claim 1, wherein: The dummy pattern includes a plurality of dummy lines, and the plurality of dummy lines extend in a first direction respectively and are arranged in a second direction intersecting the first direction.

3. The strain detection device according to claim 2, wherein: The plurality of strain gauges are arranged with gaps in the first direction, Each of the strain gauges includes a base line extending in the second direction and a plurality of wave lines extending from the base line in a direction toward the first direction, The plurality of dummy lines are configured to be aligned with the plurality of wave lines of the strain gauge.

4. The strain detection device according to claim 3, wherein: The plurality of dummy lines include a plurality of first lines connected to a plurality of waveform lines of one of the two adjacent strain gauges and a plurality of second lines connected to a plurality of waveform lines of the other of the two adjacent strain gauges. The plurality of first lines and the plurality of second lines are alternately arranged in the second direction.

5. The strain detection device according to claim 4, wherein: At least one of the plurality of first lines and at least one of the plurality of second lines is divided into a plurality of lines in the first direction, The disconnected portion is opposite to the first line or the second line in the second direction.

6. The strain detection device according to claim 5, wherein: The plurality of strain gauges are arranged with gaps in the first direction, Each of the strain gauges includes a base line extending in the second direction, a plurality of first wavy lines extending from the base line in one direction of the first direction, and a plurality of second wavy lines extending from the base line in a direction opposite to the one direction. The dummy lines include a plurality of dummy lines configured to be aligned with the plurality of wavy lines of the strain gauge and wavy dummy lines continuously extending in the second direction in a wavy manner.

7. The strain detection device according to claim 1, wherein: The strain detection device further includes a dummy wiring pattern provided on the sheet base material in a region where the plurality of strain gauges, the plurality of dummy patterns, the plurality of power supply lines, the ground line, the first signal line, and the second signal line are not provided.

8. The strain detection device according to claim 7, wherein: The dummy wiring pattern further includes a plurality of dummy wirings, and the plurality of dummy wirings are arranged between strain gauges adjacent to each other in the first direction and provided between the strain gauge and the first signal line and between the strain gauge and the ground line.

9. A strain detection device, comprising: Sheet substrate; A plurality of strain gauges are arranged on the sheet substrate in a first direction; A plurality of power lines and a plurality of first signal lines, connected to one end of the plurality of strain gauges respectively; as well as A plurality of ground wires and a plurality of second signal wires are respectively connected to the other ends of the plurality of strain gauges, Each of the strain gauges includes a base line, a plurality of first waveform lines extending from the base line in one direction of the first direction, and a plurality of second waveform lines extending from the base line in a direction opposite to the one direction. The first corrugated line of one strain gauge and the second corrugated line of another strain gauge adjacent to each other in the first direction are aligned and positioned in the second direction.

10. The strain detection device according to claim 9, wherein: The strain detection device further includes a dummy wiring pattern provided on the sheet base material in a region where the plurality of strain gauges, the plurality of power supply lines, the ground line, the first signal line, and the second signal line are not provided.

11. The strain detection device according to claim 10, wherein: The dummy wiring pattern further includes a plurality of dummy wirings, and the plurality of dummy wirings are arranged between strain gauges adjacent to each other in the first direction and provided between the strain gauge and the first signal line and between the strain gauge and the ground line.

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