Sheet-like sensor and its manufacturing method

Abstract

To provide a sheet-like sensor with a large area, capable of detecting a shearing load, for example, the sensor including a plurality of sensor elements that can be manufactured by printing and are inexpensive.SOLUTION: In the sheet-like sensor, at least two sensor elements are arranged between one pair of sheet-like base materials facing each other, each sensor element including: a first sheet-like resistor formed in one of the base materials; a second sheet-like resistor formed in the other of the base materials 3, the first and second resistors facing each other and being in contact with each other so that the second resistor can be relatively dislocated with respect to the first resistor; and a joint unit for connecting the pair of base materials and determining the position of the second resistor with respect to the first resistor in each sensor element.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a sheet-like sensor. [Background technology]

[0002] There is a demand for large-area sheet-type sensors to detect the condition of a patient in bed in medical and nursing care settings. In particular, inexpensive sheet-type tactile sensors are not widely used, and there is a demand for sheet-type tactile sensors that can be easily manufactured using printing technology. Touch is an organ that detects vibration, stress, pressure, and temperature, either alone or in combination, and there are known methods of sensing vibration, stress, pressure, and temperature that imitate touch, particularly a method of measuring these using a sheet-shaped sensor. A known tactile sensor that uses such a method is a resistor sensor that detects load from a change in value of a resistor due to an external stimulus. Resistance change sensors are low-cost because they have a simple structure and can be manufactured by printing, and there are many examples of their use as tactile sensors.

[0003] In a resistance change type sensor element, a load in one axial direction of the sensor medium (for example, the vertical Z-axis) is detected as a change in resistance. When detecting a shear load parallel to the XY plane, sensor elements for detecting the Z-axis are arranged in a matrix, and shear motion parallel to the XY plane is detected from the time change in the shear load detected by each of the adjacent sensor elements. A shear load sensor has also been realized by configuring a three-dimensional structure for detecting a shear load parallel to the XY plane (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-68503 A Summary of the Invention [Problem to be solved by the invention]

[0005] When trying to detect shear load in the XY plane using conventional resistance change type tactile sensors, increasing the number of elements makes the wiring from the sensor elements and the control system more complicated, making it difficult to provide a large-area, sheet-like tactile sensor. Furthermore, in the method of Patent Document 1, since the detection element has a complex structure, it is difficult to configure a large-area, sheet-like sensor that detects a change in shear load in the XY plane. In view of these problems, the present disclosure provides a sheet-like sensor that can be manufactured by printing at low cost and has a large area. [Means for solving the problem]

[0006] In order to solve the problem, a sheet-like sensor according to one embodiment of the present disclosure has two or more sensor elements arranged between a pair of opposing sheet-like substrates, and each sensor element has a sheet-like first resistor formed on one of the pair of substrates arranged opposite a sheet-like second resistor formed on the other substrate, and the first resistor and the second resistor are in contact with each other in a state in which the second resistor can be displaced relatively to the first resistor, and further has a joint that connects the pair of substrates and positions the second resistor relative to the first resistor in each sensor element.

[0007] Another aspect of the sheet-like sensor of the present disclosure comprises a pair of substrates whose surfaces other than their main surfaces are covered with exterior parts, a sensor element arranged between the main surfaces of the pair of substrates, and a hole provided from the surface of the exterior part of each of the pair of substrates to the substrate, wherein the hole provided in one of the pair of substrates is provided at a position that does not overlap with the outline of the hole provided in the other of the pair of substrates in a planar view.

[0008] Furthermore, a method for manufacturing a sheet-type sensor according to an aspect of the present disclosure includes the steps of: pattern-printing resistors on a sheet-type first substrate to form a plurality of sheet-type first resistors; pattern-printing resistors on a sheet-type second substrate to form second resistors at positions that can face the first resistors; forming a plurality of joints on one of the first substrate or the second substrate so as to surround the periphery of an area in which one or more first resistors or one or more second resistors are formed in a planar view; overlapping the second substrate on the first substrate so that the first resistors and the second resistors face each other; and bonding the joints to the other of the first substrate or the second substrate to connect the first substrate and the second substrate. Effect of the Invention

[0009] According to an aspect of the present disclosure, there is provided a large-area sheet-like sensor including a plurality of sensor elements that can be manufactured inexpensively by printing, and a method for manufacturing the sheet-like sensor. [Brief description of the drawings]

[0010] [Figure 1] 1 is a configuration diagram of a sheet-type sensor according to a first embodiment based on the present disclosure. [Diagram 2] 1 is a cross-sectional view of a sheet-type sensor according to a first embodiment of the present disclosure. [Diagram 3] 3A and 3B are configuration diagrams in which the sensor element according to the first embodiment of the present disclosure is a shear force detection sensor, with FIG. 3A being a plan view and FIG. 3B being a cross-sectional view. [Figure 4] 4A and 4B are diagrams showing examples of arrangements of a sensor element and a joint according to a first embodiment of the present disclosure, where FIG. 4A is a plan view of one example of arrangement, and FIG. 4B is a plan view of another example of arrangement. [Diagram 5] 3A to 3C are diagrams illustrating an example of a manufacturing process for the sheet-type sensor according to the first embodiment based on the present disclosure. [Figure 6] FIG. 1 is a configuration diagram of a temperature sensor according to a first embodiment based on the present disclosure, where (a) is a plan view and (b) is a cross-sectional view. [Figure 7]FIG. 2 is a diagram of an example arrangement in which one of the sensor elements according to the first embodiment based on the present disclosure is a temperature sensor element. [Figure 8] FIG. 4 is a diagram of an example of wiring from a sensor element according to the first embodiment based on the present disclosure. [Figure 9] FIG. 4 is a diagram showing an example of wiring of a common electrode from a sensor element according to the first embodiment based on the present disclosure. [Figure 10] 11 is a cross-sectional view showing a first example of a sheet-type sensor according to a second embodiment of the present disclosure. FIG. [Figure 11] 11 is a cross-sectional view showing a second example of a sheet-type sensor according to a second embodiment of the present disclosure. FIG. [Figure 12] 13 is a plan view showing positions of holes provided in a substrate of a sheet-type sensor according to a second embodiment based on the present disclosure. FIG. [Figure 13] 13 is a cross-sectional view showing an example of an arrangement of a jig to be inserted into a substrate of a sheet-type sensor according to a second embodiment based on the present disclosure. FIG. [Figure 14] 13 is a cross-sectional view showing another example of the arrangement of the jig to be inserted into the substrate of the sheet-type sensor according to the second embodiment based on the present disclosure. FIG. [Figure 15] 13 is a cross-sectional view showing a configuration example when a substrate and a jig of a sheet-type sensor according to a second embodiment based on the present disclosure are integrated. FIG. [Figure 16] 11 is a schematic diagram showing a state in which a shear load is applied to a sheet-type sensor according to a second embodiment based on the present disclosure. FIG. [Figure 17] 1A and 1B are diagrams illustrating example inlay configurations of sheet-type sensors according to embodiments of the present disclosure. [Figure 18] FIG. 13 is a diagram of an example inlay configuration of a sheet of sensors arranged in a matrix, according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Next, a first embodiment and a second embodiment based on the present disclosure will be described with reference to the drawings. In each embodiment, a sheet-like sensor in which multiple pressure-sensitive sensors that output a shear load applied to the sensor as a change in resistance are arranged in a planar direction will be described as an example. Each embodiment is a sheet-like sensor that operates as a shear pressure-sensitive sensor that detects a shear load in a horizontal plane of the XY plane, which cannot be detected by a general vertical pressure-sensitive sensor.

[0012] 1. First embodiment Hereinafter, a sheet-type sensor according to a first embodiment of the present disclosure will be described with reference to FIGS. The sheet-like sensor according to this embodiment is configured by arranging a plurality of sensor elements 4, 5 and a plurality of joints 6 between a pair of base materials 2, 3, as shown in FIGS. 1 and 2, the sheet-like sensor of this embodiment is an example in which two sensor elements 4, 5 constitute one sensor pair, and a plurality of joints 6 (three in FIG. 1) are arranged so as to surround the outer periphery of the two sensor elements 4, 5 constituting one sensor pair in plan view. The sensor pair is also called a load sensor. 1 and 2 show only one set of load sensors, but multiple sets of load sensors may be disposed between the pair of sheet-like base materials 2 and 3. The multiple sets of load sensors are disposed in a matrix shape between the pair of base materials 2 and 3 in a plan view.

[0013] <Base material> The sheet-like base materials 2 and 3 are formed, for example, from a thermoplastic plastic. In this case, the base materials 2 and 3 can be joined together via a plurality of joints 6 by applying heat and pressure from the outside. The base materials 2 and 3 are made of a plastic form such as polyethylene, polypropylene, polyethylene terephthalate, polycarbonate, or acrylic. In addition, the substrates 2 and 3 may have a hard coat layer on the surface side (the surface opposite to the surface on which the sensor element is provided). This hard coat layer is, for example, composed of a cured acrylic layer. The thickness of this hard coat layer is, for example, in the range of 1 μm or more and 5 μm or less. Within this range, it is easy to prevent the substrates 2 and 3 from being scratched and the hard coat layer itself from cracking.

[0014] Furthermore, a bonding layer may be provided on the inside (opposing surface) of the base materials 2 and 3. The bonding layer is, for example, a urethane layer. The thickness of the bonding layer is, for example, in the range of 1 μm or more and 10 μm or less. The thickness of each of the substrates 2 and 3 is, for example, in the range of 25 μm to 200 μm. In this range, the substrates 2 and 3 are less likely to bend and can be rolled up. The substrates 2 and 3 can support the resistors 4A, 4B, 5A, and 5B that constitute the sensor elements 4 and 5, and can protect the sensor elements 4 and 5 from the outside.

[0015] <Sensor element> In this embodiment, the two sensor elements 4 and 5 constituting one load sensor are an X-axis resistance element and a Y-axis resistance element. Each of the sensor elements 4, 5 constituting the X-axis resistance element and the Y-axis resistance element has a sheet-like first resistor 4A, 5A formed on one of the pair of substrates 2, 3, the substrate 2, and a sheet-like second resistor 4B, 5B formed on the other substrate 3. The first resistor 4A, 5A and the second resistor 4B, 5B are disposed opposite to each other in a state in which the second resistor 4B, 5B is relatively displaceable in a planar direction (lateral direction) with respect to the first resistor 4A, 5A, and the resistive surfaces 4Aa, 5Aa of the first resistor 4A, 5A and the resistive surfaces 4Ba, 5Ba of the second resistor 4B, 5B are in circumferential contact with each other to form a contact surface 10.

[0016] When a shear load is applied in the X-axis direction, the contact area between the first resistor 4A and the second resistor 4B changes, and the resistance value of the X-axis resistor (sensor element 4) changes in response to the shear displacement. Similarly, the resistance value of the Y-axis resistor (sensor element 5) changes in response to a shear load in the Y-axis direction. Note that the coordinate system indicated by the X-axis and Y-axis does not have to be an orthogonal coordinate system, and may be an oblique coordinate system.

[0017] Each sensor element 4, 5 outputs information (resistance value) for calculating the load by changing the contact area of ​​two opposing resistors 4A, 4B, 5A, 5B in response to the shear load. The shear load is calculated by measuring the resistance value when a load is applied in each of the predetermined X and Y directions and setting a calibration curve in advance. When measuring the actual shear load, the resistance value of the contact surface 10 when the shear load is applied is converted to a shear load based on the calibration curve and calculated.

[0018] Here, it is sufficient that the resistance value of the contact surface 10 of the first resistor 4A, 5A and the second resistor 4B, 5B of each sensor element 4, 5 is set to a few Ω to a few hundred Ω. In addition, since the resistance value of each material of the resistors 4A, 4B, 5A, 5B forming the sensor elements 4, 5 becomes a conductive path for measuring the resistance value of the contact surface 10, it is sufficient to select a combination of material and dimensions that shows a resistance value lower than the resistance value of the contact surface 10. The resistance value of the contact surface 10 may be adjusted by adjusting the surface roughness to increase or decrease the contact area.

[0019] The first resistors 4A, 5A and the second resistors 4B, 5B are made of, for example, a resin having electrical conductivity. The resin having electrical conductivity can be formed by pattern printing or coating the surfaces of the substrates 2, 3 with a conductive ink in which carbon filler or metal filler is dispersed in a binder resin. In addition, an oxide film may be formed on the surface of the metal pattern (pattern of the lead wires (wirings 50 to 55), see Figs. 8 and 9) to adjust the resistance value of the contact surface 10. When the first resistors 4A, 5A and the second resistors 4B, 5B are formed by pattern printing, it is easy to arrange the sensor elements 4, 5 individually. Examples of printing methods include screen printing, gravure printing, and inkjet printing. Examples of coating methods include gravure coating, electrostatic spraying, and die coating. In the coating method, the resistor elements are formed using a mask of the pattern.

[0020] Here, when applying a shear load accompanied by actual shear displacement, the shear load is always applied with a vertical (opposing) Z-axis load also applied. The shear displacement is determined by the viscoelastic properties of the material of the joint 6 when the difference between the frictional force at the contact surface 10 when the Z-axis load is applied, which acts as a resistance to the shear load, acts on the joint 6. For this reason, when calculating the shear load, it is preferable to correct the calculated value based on the Z-axis load and the viscoelastic properties of the material of the joint 6. The Z-axis load can be detected by adding the sensor elements 4 and 5 configured as described above for pressure detection.

[0021] That is, when applying a shear load accompanied by an actual shear displacement, the shear load is always applied in a state where a Z-axis load in the vertical direction (opposite direction) is applied. In addition, the shear displacement is determined by the viscoelastic properties of the material of the joint 6 when the difference between the frictional force at the contact surface 10 of the Z-axis load application acting as a resistance force against the shear load acts on the joint 6. For this reason, when calculating the shear load, it is preferable to correct the calculated value by the Z-axis load and the viscoelastic properties of the material of the joint 6. The Z-axis load can be detected by adding the sensor elements 4 and 5 having the above configuration for pressure detection. That is, although not shown in the figure, a resistance value change type vertical load sensor can be added and arranged for each load sensor, and the load sensor can be a three-axis sensor that detects the Z axis in addition to the X axis and Y axis. In this case, the frictional force acting on the contact surface 10 from the Z-axis load may be corrected, and the calibration curve of the shear load from the vertical load may be adjusted. Furthermore, wiring (lead wires) for measuring resistance values ​​are provided from the sensor elements 4 and 5 on the base materials 2 and 3. The lead wires may be formed using a printed wiring board, or may be printed using a conductive ink such as silver paste.

[0022] <Joint part> The joint 6 is provided on each load sensor. The joint 6 is disposed on the outer periphery of the plurality of sensor elements 4, 5 constituting the corresponding load sensor, connects between the pair of substrates 2, 3, and connects the first resistors 4A, 5A of the sensor elements 4, 5 constituting the corresponding load sensor. The joint 6 determines the initial positions (positions under no load) of the sensor elements 4 and 5 in the three axial directions of the X, Y and Z directions. As shown in FIG. 2, the opposing substrates 2 and 3 are connected only at a joint 6, and the X-axis resistive element 4 and the Y-axis resistive element 5 have a contact surface 10 consisting of an interface where the surfaces of the opposing resistors 4A, 4B, 5A, and 5B (resistive surfaces 4Aa, 5Aa, 4Ba, and 5Ba) come into contact with each other.

[0023] The joint 6 may be formed, for example, by a pillar-shaped patch, or may be formed by printing on the surface of one or both of the pair of base materials 2 and 3 . After the material of the joint 6 is formed using a pressure sensitive adhesive or adhesive, the base materials 2 and 3 can be joined at the joint 6 by pressure bonding. The joint 6 can also be formed from a thermoplastic material. In this case, the material forming the joint 6 is heated and fused by thermocompression bonding using a laminator that applies heat to the entire surface, thereby joining the base materials 2 and 3 via the joint 6. As another method for forming the joint 6, the above-mentioned base materials 2 and 3 can be made of a thermoplastic material, or a separate joint layer made of a thermoplastic material can be provided below the load sensor element pattern, and then a patterned thermal stamp can be pressed against the position of the joint 6 to heat and bond only the joint 6 portion, thereby joining the base materials 2 and 3.

[0024] The material of the joint 6 is selected from, for example, elastic resins. Specific examples of the material of the joint 6 include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinyl acetate, polyurethane, etc. The material of the joint 6 and the joining process are not limited as long as the material can join the base materials 2 and 3 by adhesion and solidification through thermoplasticity, thermosetting, UV curing, etc. during the joining process. It is preferable that the material of resistors 4A, 4B, 5A, and 5B is harder than the material of joint 6, since this can prevent resistors 4A, 4B, 5A, and 5B from being deformed.

[0025] The joint 6 may be thicker or thinner than the thickness of the sensor elements 4, 5. When the joint 6 is thicker, the portion surrounded by the joint 6 has a concave shape. When the joint 6 is thinner, the portion surrounded by the joint 6 has a convex shape. In this embodiment, the joint 6 is suitably disposed with respect to the sensor elements 4 and 5 as described below, so that the friction of the contact surface 10 during shear load is stabilized. In this embodiment, as shown in FIG. 1, for each load sensor, three or more joints 6 are arranged so as to surround the outer periphery of a plurality of sensor elements 4 and 5 that constitute the load sensor.

[0026] The three or more joints 6 are, for example, arranged in a plan view on a first circle 30 centered on the center of mass of the two or more sensor elements 4, 5 constituting the corresponding sensor set, and are provided at positions where the distance between adjacent joints 6 is equal (equally spaced positions). That is, each joint 6 is arranged at a corner position of a regular polygon shape (having the same number of corners as the number of joints 6) centered on the center of the first circle 30. In this case, the two or more sensor elements 4, 5 constituting each load sensor are arranged so as to be inscribed in a second circle 20 centered on the center of mass, and the radius of the first circle 30 is preferably twice or less than the radius of the second circle 20.

[0027] That is, in this embodiment, in order to apply a load to the surfaces of the resistors 4A, 4B, 5A, and 5B evenly in response to a Z load, the sensor elements 4 and 5 are arranged inside a circle centered on the center of mass, and three or more joints 6 are arranged within a circle that is 1 to 2 times the radius of the circle circumscribing the sensor elements 4 and 5 from the center of the sensor elements 4 and 5. By placing the joints 6 within a circle that is 2 times the radius, the opposing resistors 4A, 4B, 5A, and 5B can reliably contact each other. The positions of the joints 6 can be arranged so as to be located at the vertices of a regular polygon centered on the center of mass of the sensor elements 4 and 5. This center of mass can be a pseudo center of gravity calculated only from the outer shape of the element outline. In other words, the inside of the element outline is the center of gravity when it is assumed that the material has a uniform mass in two dimensions. This pseudo center of gravity coincides with the center of pressure applied to the element, which is preferable. The position of the center of mass of the sensor elements 4 and 5 is the center of mass of the sensor elements 4 and 5 that constitute the pair. The joint 6 is formed between the opposing substrates 2 and 3 in a dot pattern so as to surround the outer periphery of the sensor elements 4 and 5 at intervals in the circumferential direction. That is, the shape of the joint 6 can be a dot. The dot can be a circle. It can also be an ellipse. As a result, when pressure is applied, the contact surfaces 10 of the resistors 4A, 4B, 5A, and 5B are not sealed in a closed space and air escapes, eliminating air entrapment at the contact surfaces 10, and stabilizing contact at the contact surfaces 10 of each sensor element 4 and 5. By arranging the joint 6 in this manner, a vertical load is applied to the contact surfaces 10 of the resistors 4A, 4B, 5A, and 5B in the vertical direction when a Z-axis load is applied to the sheet-like sensor. The frictional force of the contact surfaces 10 of the resistors 4A, 4B, 5A, and 5B generated when the load is applied acts as a constant resistance against the shear load, and the amount of change in the area of ​​the resistors 4A, 4B, 5A, and 5B when the shear load is applied is also constant against the shear load. Furthermore, with such a structure, the load sensor is less likely to vibrate, and can be displaced stably in any direction on a two-dimensional plane.

[0028] <Example of sensor element configuration> An example of the configuration of the sensor elements 4 and 5 for detecting a shear load will be described with reference to Fig. 3(a) and Fig. 3(b). Fig. 3(a) is a plan view showing an example of the configuration of the sensor element 4, and Fig. 3(b) is a cross-sectional view showing an example of the configuration of the sensor element 4. In the sensor element 4 shown in Fig. 3(a) and Fig. 3(b), the first resistor 4A and the second resistor 4B are both rectangular, but the lengths of the long sides are different. In a plan view, the two resistors 4A and 4B are arranged so that the short sides of the two resistors 4A and 4B are aligned in the shear detection direction, and the short sides of the two resistors 4A and 4B overlap. In the long side direction, the resistor 4A or 4B with the shorter long side is set to be in the center of the resistors 4A or 4B with the longer long side. The sensor element 5 has a similar configuration.

[0029] The shapes and arrangement of the first resistor 4A, 5A and the second resistor 4B, 5B are not limited to those described above. The shapes and arrangement of the two resistors 4A, 4B, 5A, 5B arranged opposite to each other may be configured so that the area of ​​the overlapping region of the two resistors 4A, 4B, 5A, 5B changes in plan view in response to shear displacement in the direction of the shear force to be detected, and the area of ​​the overlapping region of the two resistors 4A, 4B, 5A, 5B is kept constant with respect to shear displacement in a direction perpendicular to the direction of the shear force to be detected. In this case, the first resistors 4A, 5A and the second resistors 4B, 5B are connected via the contact surface 10, and the resistance value of the contact surface 10 is converted into a shear load.

[0030] In FIG. 3(a), if the XX′ direction is the X-axis direction (shear detection direction), when shear displacement occurs in the positive X-axis direction (rightward on the paper) in response to a shear load, the overlapping area of ​​resistor 4A and resistor 4B increases, and the contact resistance decreases. Conversely, when a shear load is applied in the negative X-axis direction (leftward on the paper), the overlapping area decreases, and the contact resistance increases. By increasing or decreasing the contact resistance in the shear load direction of the X-axis, it is possible to detect shear stress. On the other hand, when shear occurs in the vertical Y-axis direction, the overlapping area of ​​resistor 4A and resistor 4B does not change even if resistor 4A slides to the end position of resistor 4B in the long side direction. As a result, the shear load in the Y-axis direction is not detected, and only the shear load component in the X-axis can be detected separately. When detecting a shear load in the Y-axis direction, if the sensor element 4 for measuring the X-axis is rotated 90°, it is possible to detect a shear load only in the Y-axis direction in the same way. By arranging two sensor elements 4 and 5 arranged at 90° different positions as one pair, a load sensor can be configured that can measure the shear load applied to the XY plane in all directions.

[0031] FIGS. 4(a) and 4(b) show examples of the arrangement of the sensor elements 4 and 5 constituting one load sensor employing the configuration example shown in FIGS. 3(a) and 3(b). The load sensor shown in FIG. 4(a) has one set of an X-axis resistive element 4 and a Y-axis resistive element 5, and three joints 6 arranged at the vertices of an equilateral triangle. The arranged joints 6 may have joints 6 with large cross sections and joints 6 with small cross sections. The ratio of the number of the large joints 6 to the small joints 6 may be, for example, 1:1 or more and 1:6 or less. The small joints 6 may be arranged on the outer periphery of the large joints 6. By arranging in this way, the stress applied to the large joints 6 can be distributed to the small joints 6. The small joints 6 may be arranged on the outer side of the large joints 6, centered on the center of mass of the sensor elements that make up the set. In this arrangement, when a part of the small joints 6 breaks, the load sensor shows an abnormal value compared to the surrounding element values, making it easy to detect the malfunction before it is completely broken and stops working.

[0032] The load sensor shown in FIG. 4(b) has two sets of X-axis resistive elements 4 and Y-axis resistive elements 5, and four joints 6 are arranged at the vertices of a regular square. By arranging the joints 6 in this way, the vertical load applied to each sensor element 4, 5 is averaged, and the contact surface load on each contact surface 10 in the load sensor is stabilized. As a result, the friction and electrical resistance of the contact surface 10 are stabilized. Furthermore, by setting the arrangement of the joints 6 as described above, even if the shear load is applied from any direction on the XY plane (two-dimensional direction), a biased shear load is applied to the sensor elements 4, 5, making it possible to measure the shear load more accurately. Note that Figures 4(a) and 4(b) show an example of this embodiment, and do not limit the number of sets of sensor elements 4 and 5 that constitute one load sensor and the number of vertices of the regular polygon in the arrangement of the joints 6.

[0033] By increasing the number of polygons in which the joints 6 are arranged, the shape approaches a circle, and the shear load is transmitted on an average basis in all directions of X and Y as shear displacement of the sensor elements 4 and 5. Also, by increasing the number of sets of the sensor elements 4 and 5 that make up one load sensor, the sensitivity is improved and accurate measurement is possible. It is also possible to measure the areal distribution of the shear load spreading in the XY plane by arranging a large number of load sensors, each consisting of a set of sensor elements 4, 5 and a joint 6, in a matrix and measuring the resistance value of each.

[0034] Note that a plurality of sets of load sensors may be arranged in a matrix between the base materials 2 and 3, or as described above, a plurality of sensor components each consisting of a set of load sensors may be prepared between the base materials 2 and 3 and laid out in a matrix on top of the other two-dimensional sensor. In this case, it is preferable to detachably attach each sensor component to the other two-dimensional sensor. It is also possible to provide robustness by arranging many sensor elements 4 and 5 with the same characteristics and detecting data with multiple element sets. In this case, even if some elements fail, the values ​​of the failed elements can be supplemented by the values ​​of the surrounding elements. Also, it is easy to detect malfunctions of elements from abnormalities among many elements.

[0035] In addition, when multiple load sensors are arranged on a single plane, in-field calibration can be easily performed by matching the values ​​of the element groups of adjacent load sensors. Machine learning may be used to detect these abnormalities and perform the calibration. In particular, since multiple load sensors are arranged, a large amount of data to be used for machine learning can be obtained, so that efficient machine learning can be performed. This machine learning may be hierarchical machine learning. In this case, the values ​​of each point themselves can be used as teacher data, or the pattern of the distribution of values ​​can be used as teacher data. In addition, data from multiple sheets can be used as teacher data. When multiple sheets are used, it is possible to detect the replacement of the sheet or an abnormality in the sheet itself from discontinuous changes in values, etc. By arranging a large number of elements with the same characteristics in this way, abnormalities in the elements and complementation by machine learning can be effectively performed.

[0036] The plurality of load sensors may be arranged in a square or hexagonal array. In addition, for improved accuracy and redundancy, the plurality of load sensors may be arranged as one cell. It is also possible to make a sheet-like sensor for detecting vibration or temperature by resolving the change in resistance value of the sensor elements 4 and 5 over time to make them a vibration detection type element, or by selecting a temperature variable resistance material for the sensor elements 4 and 5 to make them a temperature detection type element.

[0037] <Temperature sensor element> An example in which one of the sensor elements 4, 5 constituting the load sensor is a temperature sensor element 40 is shown in FIGS. As shown in Fig. 6(a) and Fig. 6(b), an example of the structure of the temperature sensor element 40 is configured so that the area of ​​the contact surface 41 between the first resistor 7 and the second resistor 8 does not change even if a displacement occurs between the substrates 2 and 3 due to shear. In the example of Fig. 6, the resistor 8 is configured so that, in a plan view, the entire resistor 8 is inside the resistor 7 within a set maximum range of the displacement due to shear. This prevents the contact area of ​​the temperature sensor element 40 from changing even if shear occurs. Therefore, the temperature can be detected stably and accurately by detecting the change in the resistance value of the resistors 7 and 8 due to temperature without being affected by shear.

[0038] 7 shows an example of a load sensor in which shear sensor elements 4, 5 and a temperature sensor element 40 are arranged together. Unlike the shear sensor elements, the arrangement of the temperature sensor element 40 is not restricted and it can be arranged near the shear elements. It is also possible to make a sheet-like sensor for planar composite tactile sensing by arranging pressure, vibration and temperature detection elements in a matrix.

[0039] <Wiring example> FIG. 8 shows an example of wiring to the sensor elements 4 and 5 that constitute the load sensor. As long as the resistance value change of each sensor element 4, 5 can be read, there are no restrictions on the wiring 50-55 connected to each resistor. However, when bonding the substrates 2, 3, the wiring pattern is formed so that the wiring to the resistors 4A, 5A of the substrate 2 and the wiring from the resistors 4B, 5B of the substrate 3 do not cross each other. If they do cross each other, an overcoat made of an insulator may be provided on the wiring. Also, as shown in FIG. 9, it is possible to simplify the wiring by integrating the electrodes on the substrates 2, 3 sides into a common electrode 60.

[0040] Also, the wiring 50-55 to each element may be in a matrix shape, and each wiring may be multiplexed. The wiring may be double, triple, or quadruple. By multiplexing, even if one wiring is broken, the measurement can be continued. In this case, the breakage may be detected from the change in resistance or impedance. The wiring may be copper wire, or may be wiring formed by printing. Also, it may be formed by etching metal foil. This metal foil may be aluminum foil, copper foil, or a laminated foil of these. The metal foil or printed wiring can reduce the cost of the sheet-like sensor. In addition, when the front and back are joined at multiple points, the wiring can be passed between the joining points. In addition, the contact point between the element and the wiring, which is prone to breakage, can be contained within the joining point, so that breakage is easily prevented. In addition, a joint 6 may be provided at the part where the wiring crosses. This makes it possible to selectively strengthen the crossing part of the wiring, which is prone to breakage.

[0041] Also, the outer periphery of the sheet end of the pair of base materials 2, 3 may be joined with a continuous joint. This allows the space between the pair of base materials 2, 3 constituting the sheet-like sensor to be sealed. As a result, it is possible to prevent the intrusion of liquid, water vapor, etc. between the pair of base materials 2, 3, and prevent failure and deterioration of the sensor element. Also, when sealing, an inert gas such as nitrogen may be sealed in the space between the pair of base materials 2, 3. The amount of this sealed gas is set to be below atmospheric pressure, i.e., negative pressure, to ensure contact between the sensor elements 4, 5 and optimize the pressure of the contact.

[0042] <Manufacturing method> FIG. 5 illustrates an example of a method for manufacturing the sheet-type sensor of this embodiment. That is, the resistors 4A and 5A are pattern-printed on the sheet-like first base material 2 to form a plurality of sheet-like first resistors 4A and 5A, and the resistors 4B and 5B are pattern-printed on the sheet-like second base material 3 to form sheet-like second resistors 4B and 5B at positions that can face the first resistors 4A and 5A, respectively. Next, a plurality of joints 6 are formed on one of the first base material 2 and the second base material 3 so as to surround the periphery of the area in which one or more of the first resistors 4A and 5A or one or more of the second resistors 4B and 5B are formed in a plan view. The second base material 3 is overlaid on the first base material 2 so that the first resistors 4A and 5A face the second resistors 4B and 5B, and the joints 6 are fixed to the other base material 3 of the first base material 2 and the second base material 3 to connect the first base material 2 and the second base material 3.

[0043] An example of a method for manufacturing a sheet-type sensor will be specifically described with reference to FIG. Although FIG. 5 illustrates an example in which one set of load sensors is provided, two or more sets of load sensors may be provided. As shown in FIG. 5(a), in the first step, resistors 4A, 4B, 5A, and 5B are pattern-printed on each of the base materials 2 and 3 to form sheet-like first resistors 4A and 5A and sheet-like second resistors 4B and 5B on the base materials 2 and 3, respectively. 5(b), in the second step, the bonding portion 6 is formed on one of the base materials 2. It does not matter whether the bonding portion 6 is formed on either of the base materials 2 and 3.

[0044] Next, as shown in FIG. 5(c), in the third step, the resistive surfaces of the corresponding resistors 4B, 5B of the pair of opposing resistors 4A, 5A are brought into contact with each other, and the pair of substrates 2, 3 are temporarily fixed with the joint 6 sandwiched therebetween. Thereafter, the joint 6 is joined to the other substrate 3, thereby connecting and fixing the pair of substrates 2, 3 at the joint 6. In this way, a sheet-shaped sensor can be produced. Here, the joint 6 may be formed by pattern printing using a bonding material resin ink as described above, or a bonding material resin paint may be coated between the substrates 2, 3 and the resistor 4A, 4B, 5A, 5B pattern to form a two-layer sealant structure of the substrates 2, 3 and a thermoplastic resin as a bonding material, and the joint 6 may be fixed by lamination bonding by pattern heating.

[0045] 2. Second embodiment Hereinafter, the sheet-like sensor 101 according to the second embodiment of the present disclosure will be described with reference to FIGS. The sheet-like sensor 101 according to the second embodiment is a pressure-sensitive sensor that outputs a shear load applied to a medium as a change in a physical quantity such as a resistance value. In conventional sheet-type tactile sensors capable of measuring shear loads, when a shear load is applied from the surface, slippage occurs on the sensor surface, and the shear is not transmitted to the pressure-sensitive layer inside the sheet, making it difficult to measure the shear load accurately. To address this issue, methods have been used to reduce slippage by sandwiching a high-friction sheet between the load-applying body and the sensor surface, or to fix the load-applying body and the sensor surface with adhesive. With the method of inserting a high-friction sheet, the deformation of the high-friction sheet itself and the slippage of the contact surface are reduced, but the reduction in slippage is not sufficient, and only a part of the applied shear load is transmitted to the pressure-sensitive layer. With the method of fixing with adhesive, the shear load is transmitted to the pressure-sensitive layer, but since the load-applying body is fixed to the sensor with adhesive, the measurement is destructive, and there is a problem that the use of the sensor as a tactile sensor is significantly restricted. The sheet-like sensor 101 according to this embodiment, even in the case of a sheet-type tactile sensor, can reliably transmit a shear load applied to the sensor surface to the pressure-sensitive layer, enabling accurate measurement of the shear load.

[0046] 10 is a cross-sectional view showing an example of a configuration of the sheet-like sensor 101 of the present disclosure. In the sheet-like sensor 101, a sensor element 104 is formed in a form sandwiched between a first substrate 102 and a second substrate 103. In addition, in the sheet-like sensor 101, an exterior part 108 that covers the surface other than the main surface of the substrate 102 and an exterior part 109 that covers the surface other than the main surface of the substrate 103 are formed. When a shear load is applied to the sensor surface, a shear displacement corresponding to the shear load occurs between the substrate 102 and the substrate 103, and a strain due to the displacement is transmitted to the sensor element 104 present between the substrate 102 and the substrate 103, thereby measuring the shear load.

[0047] <Sensor element> As an example of the configuration of the sensor element 104, a resistor 104A (not shown) formed on the first base material 102 and a resistor 104B (not shown) formed on the second base material 103 are in contact with each other at resistor surfaces 104Aa and 104Ba to form the sensor element 104. Note that the arrangement of the resistors 104A and 104B of the sensor element 104 is similar to the arrangement of the first resistor 4A and the second resistor 4B shown in Figures 3(a) and 3(b), and therefore a detailed description of the arrangement will be omitted. When a shear displacement occurs between the substrate 102 and the substrate 103 due to the application of a shear load, the contact area between the substrate 102 and the substrate 103 changes, causing the resistance value to rise and fall. The shear load is calculated by converting this change in resistance value into the applied load.

[0048] Also, a sensor element may be formed whose resistance value changes according to the shear displacement in each of the X and Y directions. That is, when a shear load is generated in the X-axis direction, the contact area between the first resistor 104A and the second resistor 104B changes in the X-axis sensor element, and the physical quantity such as the resistance value changes according to the shear displacement. Similarly, the physical quantity such as the resistance value changes in response to the shear load in the Y-axis direction. If the sensor element 104 is configured by combining two such resistor elements, it is also possible to measure the direction and magnitude of the shear load applied to the XY plane. The sensor element 104 may have any configuration as long as it can detect a change in a physical quantity in response to a shear load. Although the above-mentioned resistance change type sensor is widely used as the sensor element 104, a capacitance change type sensor having a capacitor structure may also be used.

[0049] The sensor elements 104 are formed on the base materials 102 and 103 by a printing or coating method. Printing is particularly preferable because it is easy to arrange each of the multiple sensor elements 104 individually. Specifically, printing methods include screen printing, gravure printing, and inkjet, while coating methods include gravure coating, electrostatic spray, and die coating. In the coating method, a mask with a pattern of the resistor element is used for formation.

[0050] <Base material> Any material that can be formed into a sheet shape may be used for the base material 102 and the base material 103. As the material for forming the base material 102 and the base material 103, it is preferable to use a resin material, and polyethylene, polypropylene, polyethylene terephthalate, polycarbonate, acrylic, etc. may be used.

[0051] The thickness of the substrates 102 and 103 is preferably 25 μm or more and 300 μm or less. If the thickness of the substrates 102 and 103 is within this range, the substrates 102 and 103 do not bend and can be rolled, and the sheet-like sensor 101 can be attached to the load applying body even if the surface of the load applying body is curved.

[0052] <Exterior part> The exterior parts 108 and 109 have the function of protecting the sheet-like sensor 101 and imparting design features to the sheet-like sensor 101 . The exterior parts 108 and 109 may be formed by laminating a pouch film or the like onto the base materials 102 and 103, or may be formed by coating the surfaces of the base materials 102 and 103 except for the main surfaces with a protective layer material or the like. Furthermore, the surfaces of the exterior parts 108 and 109 may be printed or the like. In this embodiment, the materials and configurations of the exterior parts 108 and 109 are not limited to those described above, and can be appropriately selected depending on the intended use.

[0053] <hole> The sheet-like sensor 101 according to this embodiment includes two or more holes provided in each of the substrate 102 and the substrate 103. The holes are provided so as to communicate from the surface of the exterior part 108 to the substrate 102, and may penetrate from the surface of the exterior part 108 to the main surface of the substrate 102 (the surface facing the substrate 103). Holes are similarly provided in the exterior part 109 and the substrate 103. That is, the holes may be formed from the exterior parts 108 and 109 to partway through the substrates 102 and 103, or may penetrate the substrates 102 and 103.

[0054] Fig. 10 is a cross-sectional view showing a first example of a sheet-like sensor 101 (101A) having a hole 105 formed from the exterior parts 108 and 109 to partway through the base materials 102 and 103. Fig. 11 is a cross-sectional view showing a second example of a sheet-like sensor 101 (101B) having a hole 106 penetrating from the exterior part 108 to the base material 102 and a hole 107 penetrating from the exterior part 109 to the base material 103.

[0055] In the sheet-like sensor 101A shown in Fig. 10, the holes 105 provided in one substrate (e.g., substrate 102) are provided at positions that do not overlap with the holes 105 provided in the other substrate (e.g., substrate 103) in a plan view (positions that do not coincide in the vertical direction in the cross-sectional views of Figs. 10 and 11). Similarly, in the sheet-like sensor 101B shown in Fig. 11, some of the holes 106 provided in one substrate (e.g., substrate 102) are provided at positions that do not overlap with the holes 107 provided in the other substrate (e.g., substrate 103) in a plan view. This makes it possible to easily transmit the shear load to the pressure-sensitive layer of the sensor element 104 when the shear load is applied, thereby improving the accuracy of the shear load measurement by the sheet-like sensor 101.

[0056] More specifically, when a shear load is applied, a vertical load is also applied at the same time. However, if hole 105 in substrate 102 and hole 105 in substrate 103 are positioned so as to overlap in a planar view, local pressure due to the vertical load is applied to the edge portion of the hole, making it difficult for the shear load to be transmitted to the pressure-sensitive layer of sensor element 104. In a sheet-like shear load sensor, when a shear load parallel to the main surfaces (XY planes) of the substrates 102 and 103 is applied, a load in the thickness direction (Z-axis direction) of the substrates 102 and 103 is also applied to the substrates 102 and 103 at the same time, to some extent. Application of a vertical load causes the substrates 102 and 103 to come into close contact with each other, generating friction at the interface. The shear load transmitted to the sensor element 104 is determined by the force relationship between this interface friction and the friction between the surface of the sheet-like sensor 101 and the load applicator, but in many cases, the interface friction between the substrates 102 and 103 is large, making it difficult for the shear load to be transmitted to the sensor element 104. The sheet-like sensor 101 has a hole structure extending in the thickness direction of the substrates 102 and 103, which makes it possible to efficiently transmit the applied shear load from the substrates 102 and 103 to the sensor element 104 in contact with the substrates 102 and 103 by utilizing the holes.

[0057] As shown in FIG. 10, the formation of a hole 105 with a bottom inside the substrate 102, 103 can be achieved by a method such as laser processing, embossing in which a special layer is provided on the surface of the substrate 102, 103 or on the surface of the substrate 102, 103 and then pressed, a physical formation method using a drill, or a method of raising the area other than the hole formation area by using a resin material or the like through printing or coating. As shown in FIG. 11, holes 106 and 107 penetrating base materials 102 and 103 can be formed by punching using a punch or a punching blade, and punching may be performed together with exterior parts 108 and 109 .

[0058] Fig. 12 is a plan view schematic diagram showing the arrangement of holes 105 in the substrate 102 or substrate 103 of the sheet-like sensor 101A shown in Fig. 10. In the sheet-like sensor 101, it is preferable that a plurality of holes are provided in one substrate. When a plurality of holes are provided in one substrate, it is possible to suppress a change in the direction of the shear applied to the pressure-sensitive layer caused by the substrate 102 or 103 rotating about the hole with respect to the direction of the XY plane.

[0059] In order to transmit shear from all directions evenly to the pressure-sensitive layer, when an even number of holes 105 are formed, the holes 105 are arranged at positions equidistant from the center O of the sensor element 104, as shown in Figures 2(a), 2(b), and 2(c). When an odd number of holes 105 are formed, as shown in Figure 2(d), the holes 105 are arranged at the vertices of a regular polygon having the center of gravity at the center O of the sensor element 104. Here, the "regular polygon" is a regular polygon having a number of vertices corresponding to the number of holes. In the sheet-like sensor 101B shown in FIG. 11, holes are arranged at similar positions.

[0060] The sheet-like sensor 101 may also include a jig 120 that penetrates from the exterior part 108 in the hole 105 to the base material 102. That is, the jig 120 is inserted into the hole 105 and connects the exterior part 108 and the base material 102 in the hole 105. 13 and 14 are cross-sectional views showing configuration examples of the sheet-like sensor 101 when the holes 105 are combined with the jig 120. The base material 102 and the base material 103 each have two or more holes 105 or holes 106 and 107 formed therein.

[0061] 13(a) and 13(b) are schematic cross-sectional views showing the configuration of a jig 120 in a sheet-like sensor 101A in which holes 105 having bottoms are formed inside the substrates 102 and 103. As shown in Fig. 13(a), the jig 120 may be in the shape of a pin including a protrusion 120A inserted into a plurality of (e.g., two) holes 105 and a connection portion 120B connecting the protrusions 120A to each other on the surfaces of the exterior portions 108 and 109. As shown in Fig. 3(b), the protrusions 120A of such a jig 120 are inserted into the respective holes 105. By moving the exterior part 108 in the horizontal direction with the jig 120 inserted, shear is transmitted from the jig 120 to the hole 105, and then to the sensor element 104, thereby measuring the shear load. In this manner, it is possible to accurately measure the shear load without relying on the frictional force between the load applicator and the sheet-like sensor 101. In addition, by removing the jig 120 after using the sheet-like sensor 101, the sheet-like sensor 101 becomes reusable.

[0062] The jig 120 can be a structure having a cylindrical pin as a protrusion 120A having a diameter smaller than the diameter of the hole 105. As a material for the jig 120, a material that does not deform when a shear force is applied, such as a metal or ceramic, can be selected.

[0063] 14 is a schematic cross-sectional view showing the configuration of a jig 120 in a sheet-type sensor 101B in which holes 106 and 107 are formed penetrating the base materials 102 and 103. In the sheet-type sensor 101B, in order to prevent holes having the same outer shape from being disposed at the end of the penetration, the outer shape of one of the base materials 102 and 103 is made smaller than the other, and the protrusion 120A of the jig 120 penetrates only the hole 106 formed in the other.

[0064] In FIG. 14, the outer shape of the substrate 103 is made smaller than that of the substrate 102, and a hole 106 is formed in the portion of the substrate 102 that does not overlap with the substrate 103. When the hole 106 and the hole 107 are formed in the portion where the substrate 102 and the substrate 103 overlap, the hole 106 in the substrate 102 is formed below the hole 107 formed in the substrate 103. At this time, the outer diameter of the hole 106 on the substrate 102 side is formed larger than the outer diameter of the hole 107. It is preferable to set the amount by which the outer diameter of one hole (hole 106) is increased to an amount that causes shear displacement when shear is applied. This is because the jig 120 inserted from the substrate 103 side during shear measurement will not hit the hole 106 formed in the substrate 102. Since the amount of shear displacement caused by the application of a shear load is about several hundred μm, it is preferable to set the difference between the outer diameter of the opposing hole 106 and the outer diameter of the hole 107 to about 1 mm. Specifically, when hole 107 has a diameter of 2 mm, the diameter of hole 106 facing hole 107 should be set to 3 mm.

[0065] Fig. 15 is a cross-sectional view showing a configuration example of the sheet-like sensor 101 when the jig 120 and the sheet-like sensor 101A shown in Fig. 10 are integrated together. The load layer 110 has protrusions 110A filling the holes 105, and connection parts 110B formed on the surfaces of the base material 102 and the base material 103, respectively. A rigid body such as metal or ceramic is selected as the material for forming the load layer 110. Although it is possible to use a material having a viscous component such as resin as the material for forming the load layer 110, in this case, since the shear force is difficult to transmit to the protrusion 110A, a hard resin or a material that has been hardened is selected. The portion on the surface of the base materials 102, 103 where the load layer 110 is formed should be limited to the place where the load is actually applied. By adopting such an integrated configuration, it is possible to transmit the shear load to the sensor element 104 without preparing a separate jig 120. A similar integrated structure can also be used in the sheet-like sensor 101B shown in FIG.

[0066] FIG. 16 is a schematic diagram showing a state in which a shear load is applied to the sheet-like sensor 101 by the load applying body 130. The load applying body 130 is an object to be measured for shear force, and there are no particular restrictions on the shape or material. When a shear force is applied obliquely by the load applying body 130, the shear load component is transmitted to the sensor element 104 as shear force by the protrusions 110A of the load carrying layer 110 at the holes 105 of the substrate 103. The material and surface shape of the surface of the load carrying layer 110 can be selected so that friction with the load applying body 130 is increased. There are no restrictions on the material or shape as long as the friction is high, but for example, metal or ceramic with micro-protrusions formed thereon is selected. In this manner, a sheet-like sensor 101 is obtained that enables stable measurement of shear loads in all directions on the XY plane using a sheet-like medium.

[0067] <Modification> The sensor element 104 may have a pressure-sensitive layer that detects shear as a change in physical quantity, as well as an elastic joint (not shown in FIG. 10) that operates elastically in response to a shear load and joins the substrate 102 and the substrate 103. By providing the elastic joint, the substrate 102 or the substrate 103 can be restored to its initial position when the shear load is released, making it easier to measure the shear load when a continuously changing shear load is applied.

[0068] Moreover, the sheet-like sensor 101 can be a three-axis sensor with a detection direction in the Z-axis direction in addition to the X-axis direction and the Y-axis direction by further including a resistance change type vertical load sensor. The sensor element 104 may have a lead-out wiring for outputting a change in physical quantity. As the lead-out wiring, a printed wiring board may be used, or a conductive ink such as silver paste may be printed.

[0069] 3. Usage example A usage example of the sheet-type sensor will be described below. In the following, a usage example of the sheet-type sensor 1 of the first embodiment will be described as an example. The sheet-like sensor of this embodiment may be an inlay inserted into a case. By inserting this inlay into the case, a two-dimensional sensor can be formed. The case into which the inlay is inserted may have a pocket for each inlay. The inlay may be inserted into the pocket. This allows the inlay to be positioned at a predetermined position. Each sheet-like sensor may be fixed in the case by interlocking or the like. This fixation may occur when pressure is applied to the two-dimensional sensor. The fixation of the inlay may be detachable. By making the inlay detachable, it becomes easy to replace the inlay if it is damaged. The two-dimensional sensor may be housed in a cover and used. The case may be a bag body, and the sheet-like sensors may be laid out inside the case.

[0070] FIG. 17 shows an inlay 70 consisting of a sheet-like sensor in which a pair of load sensors are provided between band-like substrates 2 and 3. FIG. 18 illustrates a two-dimensional sensor 71 in which the inlays 70 shown in FIG. 17 are arranged in a matrix on a case. The inlays 70 can be arranged at equal intervals or at different intervals for each region. By varying the intervals for each region, the sensing density can be changed within the surface. Arranging them at equal intervals allows for uniform sensing. Each sheet-like sensor that constitutes the inlay 70 may have two or more sets of load sensors.

[0071] The ends of the case or the ends of the pocket may be sealed. The seal may be waterproof. The seal may be a zipper. The waterproof seal can prevent damage to the inlay due to water ingress. The waterproof seal can also prevent contamination of the inlay, especially when the case is placed on a bed. The two-dimensional sensor 71 in which the inlay is inserted into a case having waterproof seals on the ends is hygienic.

[0072] In addition, when one of the multiple sensor elements constituting one load sensor is a pressure sensor element, it may be of the capacitance type. The pressure sensor element may also be composed of a piezoelectric element. A temperature sensor element as described above may also be provided. The temperature sensor element may also be used to calibrate the pressure sensor element. In particular, when an inlay 70 is used, the area can be easily increased by increasing the number of inlays 70.

[0073] <Action and effect> According to the aspect of the present disclosure, by configuring the components of the sensor elements 4, 5 that detect a shear load or the like by a change in resistance value of the surface contact area between the first resistors 4A, 5A and the second resistors 4B, 5B in a sheet-like form, it becomes possible to manufacture a sheet-like sensor by a printing method. As a result, according to the aspect of the present disclosure, even if a sheet-like sensor with a large area is configured by arranging a plurality of sensor elements 4, 5, it is possible to provide a sheet-like sensor that is an inexpensive sensor that can be manufactured by printing and can be made large in size. In this way, the present disclosure makes it possible to provide a load sensor that can stably measure shear loads in all directions on the XY plane using a sheet-shaped medium.

[0074] <Other> The present disclosure can also be configured as follows. (1) A sheet-type sensor comprising: two or more sensor elements disposed between a pair of opposing sheet-type substrates; each of the sensor elements is disposed such that a sheet-type first resistor formed on one of the pair of substrates faces a sheet-type second resistor formed on the other of the pair of substrates; the first resistor and the second resistor are in contact with each other in a state in which the second resistor can be displaced relatively to the first resistor; and a joint that connects the pair of substrates and positions the second resistor relative to the first resistor in each sensor element.

[0075] (2) The two or more sensor elements form a sensor set for each of the plurality of sensor elements. (3) Three or more of the joints are provided for each pair of sensors, and the three or more joints are arranged, in a planar view, in the shape of a first circle centered on the center of mass of two or more sensor elements that constitute the corresponding pair of sensors, and the distance between adjacent joints is equal.

[0076] (4) Two or more sensor elements constituting a sensor group are arranged so as to be inscribed in a second circle centered on the center of mass, and the radius of the first circle is not more than twice the radius of the second circle. (5) The multiple sensor elements constituting the sensor group include two or more shear force detection sensors that detect shear force, and in a planar view, the directions of the shear forces detected by the two or more shear force detection sensors are different from each other. The two resistors arranged opposite each other in each shear force detection sensor are configured in shape and arrangement so that, in a planar view, the area of ​​the overlapping region of the two resistors changes in response to shear displacement in the direction of the shear force to be detected, while the area of ​​the overlapping region of the two resistors is maintained constant against shear displacement in a direction perpendicular to the direction of the shear force to be detected. (6) The sensor device includes a plurality of sets of sensors, which are arranged in a matrix in plan view.

[0077] (7) A sheet-type sensor comprising a pair of substrates, the surfaces of which except for the main surfaces are covered with exterior parts, a sensor element disposed between the main surfaces of the pair of substrates, and holes provided from the surfaces of the exterior parts of each of the pair of substrates to the substrate, wherein the holes provided in one of the pair of substrates are provided at a position that does not overlap with holes provided in the other of the pair of substrates in a planar view. (8) The holes are provided in multiple numbers in each of the pair of substrates, and when an even number of the holes are provided, they are arranged at positions equidistant from the center of the sensor element in a planar view. When an odd number of the holes are provided, they are arranged at the vertices of a regular polygon having the center of gravity at the center of the sensor element in a planar view.

[0078] (9) A jig is provided that penetrates from the exterior portion within the hole to the base material. (10) The jig is pin-shaped.

[0079] (11) The jig is made of metal or ceramic. (12) The holes penetrate from the surface of the exterior portion to the main surface of the substrate, a hole provided in the main surface of one of the pair of substrates is provided at a position overlapping in a planar view with a hole provided in the other of the pair of substrates, and the jigs are connected to each other via the main surfaces of the substrates.

[0080] (13) A resistor pattern is printed on a sheet-like first substrate to form a plurality of first resistors, a resistor pattern is printed on a sheet-like second substrate to form a second resistor at a position opposite the first resistor, and a plurality of joints are formed on one of the first substrate or the second substrate so as to surround an outer periphery of an area where one or more of the first resistors or one or more of the second resistors are formed in a plan view, the second substrate is overlaid on the first substrate so that the first resistors and the second resistors face each other, and the joints are fixed to the other of the first substrate or the second substrate to connect the first substrate and the second substrate. EXAMPLES

[0081] Next, an example based on the first embodiment will be described.

[0082] (1) Example 1 <Example 1-1> A sheet-like sensor having the structure shown in FIG. 1 was formed by the following method. A 100 μm PET film was used as the substrate. Resistors were printed on each of the pair of substrates using carbon ink (manufactured by Jujo Chemical, product name: JELCON CH-N). At this time, a sheet-shaped first resistor and a sheet-shaped second resistor were formed on one surface of one substrate, and a sheet-shaped first resistor and a sheet-shaped second resistor were formed on one surface of the other substrate, and the resistors were brought into contact with each other to form a sensor element. Each resistor was formed so as to be inscribed within a radius of 7 mm centered on the center of mass of the two sensor elements. Polyethylene (made by Nippon Polyethylene, product name: Novatec LC525) was used as the material for the joints on the outer periphery of the sensor element. The three joints were formed within a 10 mm range from the center of mass of the two sensor elements, at the vertices of an equilateral triangle with respect to the center. Each joint was a cylinder with a diameter of φ3 mm.

[0083] Then, one of the substrates on which the joint was formed was aligned with the other substrate, with the opposing surfaces of the resistors facing each other aligned, and the substrate was temporarily secured in place with the joint sandwiched between them. The substrate was then hot laminated at 120 degrees to adhere the tip of the joint to the substrate. Through the above steps, a sheet-type sensor having one set of load sensors was fabricated. When a vertical load of 20N was applied to the sheet sensor in the Z-axis direction and a shear load of 8N was applied in the horizontal direction, it was observed that the resistance values ​​of sensor elements 4 and 5 corresponding to the X and Y directions changed within a range of 200Ω±30Ω.

[0084] (2) Example 2 Below, examples based on the second embodiment will be described.

[0085] <Example 2-1> A sheet-like sensor having the structure shown in FIG. 10 was formed by the following method. A 100 μm PET film was used as the substrate. Resistors were printed on the pair of substrates using carbon ink (manufactured by Jujo Chemical, product name: JELCON CH-N). At this time, the pair of resistors were brought into contact with each other so that parts of them overlap in the shear force detection direction to form a sensor element. When shear displacement occurs in one direction due to shear, the contact area between the resistors changes, and the change in shear load can be measured as a change in resistance. A punching blade was used to form a through hole with a diameter of 2.0 mm in each of the pair of substrates. The pair of substrates was fixed using double-sided tape (Teraoka Seisakusho, 7070W) as a joint material to produce a sheet-like sensor of Example 2-1. A pin-shaped jig with a diameter of 1.9 mm was fabricated to match the position of the through-holes in each of the pair of substrates. The jig was inserted into the through-holes in each of the pair of substrates, and a shear load was applied by fixing one of the jigs and applying a shear displacement to the other jig.

[0086] <Comparative Example 2-1> Comparative Example 2-2 was prepared in the same manner as in Example 2-1, except that no holes were provided in the sensor of Example 2-1.

[0087] During shearing, a high friction sheet (INOAC Corporation; Poron MX-48HF) was pressed against the material to apply shear. For Example 2-1 and Comparative Example 2-1, a vertical load was maintained at 10N or 20N to apply shear to the sheet-like sensor. Table 1 below shows the shear load [N] when the above-mentioned vertical load was maintained.

[0088] [Table 1]

[0089] As shown in Table 1, in Example 2-1, a shear load of 10 N or 20 N, the same as the normal load, could be applied. On the other hand, in Comparative Example 2-1, only a load of 3 N could be applied, and it was confirmed that at this point, a shift occurred at the contact surface between the high-friction sheet and the sensor.

[0090] Although the present disclosure has been described above using the embodiments, the technical scope of the present disclosure is not limited to the scope described in the above embodiments. It is clear to those skilled in the art that various modifications or improvements can be made to the above embodiments. It is clear from the description of the claims that such modifications or improvements can also be included in the technical scope of the present disclosure. [Explanation of symbols]

[0091] 1,101,101A,101B Sheet-type sensor 2,3,102,103 Base material 4,5,104 Sensor element 4A, 5A, 104A First resistor 4Aa, 5Aa, 104Aa Resistor surface 4B, 5B, 104B Second resistor 4Ba, 5Ba, 104Ba resistor surface 6 Joint 7 First Resistor 8 Second Resistor 10 Contact surface 20 Second Circle 30 First Circle 40 Temperature sensor element 41 Contact surface 70 Inlay 71 2D Sensor 105,106,107 hole 108,109 Exterior part 110 Load layer 110A protrusion 110B Connection 120 Jig 120A protrusion 120B Connection 130 Load application body

Claims

1. Two or more sensor elements are disposed between a pair of opposing sheet-like substrates; Each of the sensor elements includes a sheet-like first resistor formed on one of the pair of base materials and a sheet-like second resistor formed on the other of the pair of base materials, the first resistor and the second resistor being in contact with each other in a state in which the second resistor is displaceable relative to the first resistor; The sensor element further includes a joint portion that connects the pair of base materials and positions the second resistor relative to the first resistor in each sensor element, The two or more sensor elements constitute a sensor set for each of the plurality of sensor elements, The plurality of sensor elements constituting the sensor group include two or more shear force detection sensors that detect shear force, In a plan view, directions of shear forces detected by the two or more shear force detection sensors are different from each other, The two resistors arranged opposite to each other in each shear force detection sensor are configured in shape and arrangement such that, in a plan view, the area of ​​the overlapping region of the two resistors changes in response to shear displacement in the direction of the shear force to be detected, and the area of ​​the overlapping region of the two resistors is maintained constant with respect to shear displacement in a direction perpendicular to the direction of the shear force to be detected. Sheet-type sensor.

2. Three or more of the joints are provided for each set of the sensors, The three or more joints are respectively arranged in a circular shape of a first circle centered on the center of mass of the two or more sensor elements constituting the corresponding sensor set in a plan view, and the distance between adjacent joints is equal.

2. The sheet-like sensor according to claim 1.

3. The two or more sensor elements constituting a sensor set are arranged so as to be inscribed in a second circle centered on the center of mass, The radius of the first circle is equal to or greater than 1 time and equal to or less than 2 times the radius of the second circle.

3. The sheet-like sensor according to claim 2.

4. A plurality of sets of the sensors are provided, In a plan view, a plurality of the sensor sets are arranged in a matrix. The sheet-like sensor according to any one of claims 1 to 3.

5. A pair of substrates, the surfaces of which except for the main surfaces are covered with exterior parts; A sensor element disposed between the main surfaces of the pair of base materials; a hole provided so as to communicate with the substrate from a surface of the exterior portion covering each of the pair of substrates; Equipped with a hole provided in one of the pair of substrates is provided at a position not overlapping with a hole provided in the other of the pair of substrates in a plan view; A jig is provided that penetrates from the exterior portion to the base material within the hole, the holes penetrate from a surface of the exterior portion to the main surface of the base material, and a hole provided in the main surface of one of the pair of base materials is provided at a position overlapping with a hole provided in the other of the pair of base materials in a plan view; The jigs are connected to each other via the main surfaces of the base material. Sheet-type sensor.

6. The holes are provided in a plurality of the pair of base materials, and an even number of the holes are provided. When an odd number of holes are provided, the holes are disposed at positions equidistant from the center of the sensor element in a plan view, and when an odd number of holes are provided, the holes are disposed at vertices of a regular polygon having the center of gravity at the center of the sensor element in a plan view.

6. The sheet-like sensor according to claim 5.

7. The jig is pin-shaped 7. The sheet-like sensor according to claim 5 or 6.

8. The jig is made of metal or ceramic. The sheet-like sensor according to any one of claims 5 to 7.

9. forming a plurality of first resistors by printing a resistor pattern on a sheet-like first base material; a resistor pattern is printed on a sheet-like second base material to form a second resistor at a position opposite to the first resistor; a plurality of bonding portions are formed on one of the first base material and the second base material so as to surround an outer periphery of a region in which one or more of the first resistors or one or more of the second resistors are formed in a plan view; A second base material is overlaid on the first base material such that the first resistor and the second resistor face each other, and the joint portion is fixed to the other of the first base material and the second base material to connect the first base material and the second base material to form a sensor element, and two or more of the sensor elements are grouped into a sensor set for each of the plurality of sensor elements, and the plurality of sensor elements constituting the sensor set include two or more shear force detection sensors that detect a shear force, and the two or more shear force detection sensors are The directions of the shear forces to be detected are different from each other, and the first resistor and the second resistor arranged opposite to each other in each shear force detection sensor are configured to have shapes and arrangements such that, in a plan view, an area of ​​an overlapping region of the first resistor and the second resistor changes in response to shear displacement in the direction of the shear force to be detected, and the area of ​​an overlapping region of the first resistor and the second resistor is maintained constant with respect to shear displacement in a direction perpendicular to the direction of the shear force to be detected. A method for manufacturing a sheet-type sensor.

Images