Occlusal force sensor sheet

Abstract

To provide an occlusal force sensor sheet which solves an existing problem that the detection accuracy becomes lower under a specific condition.SOLUTION: An occlusal force sensor sheet 12 includes a plurality of detection units 68 that elastically deform in shape when an occlusal force caused by biting is externally applied, each detection unit having a first electrode 24 and a second electrode 26 facing each other so that pressure is electrically detected. In at least one of the plurality of detection units 68, at least one of the first electrode 24 and the second electrode 26 has a reinforcing member 84 on an outer surface side opposite to an inner surface side where the first electrode 24 and the second electrode 26 face each other, so as to suppress local deformation of the detection unit 68.SELECTED DRAWING: Figure 2A

Description

[Technical Field]

[0001] The present invention relates to a surface pressure sensor sheet that is in the form of a sheet as a whole and has detection units at a plurality of locations that electrically detect pressure applied from the outside in a surface direction. [Background technology]

[0002] Surface pressure sensor sheets that detect external pressure at multiple locations have been known for some time, for example, in JP 2018-112405 A (Patent Document 1), JP 2010-043881 A (Patent Document 2), JP 2012-181084 A (Patent Document 3), and JP 2015-136620 A (Patent Document 4).

[0003] Such a surface pressure sensor sheet has multiple detection units at different locations on the surface of the sheet, and based on the electrical pressure detection signals from these detection units, it outputs pressure detection values ​​for each detection unit, as well as outputting the pressure distribution state or pressure changes, and can be used as various sensor devices depending on the application.

[0004] The detection section in such a surface pressure sensor sheet generally has a first electrode and a second electrode arranged opposite each other, and is designed to detect changes in the electrical state between the opposing surfaces of these first and second electrodes due to pressure applied from the outside. Specifically, an intermediate layer made of, for example, a conductive layer, a dielectric layer, or a resistive layer is arranged between the opposing surfaces of the first and second electrodes, and the pressure acting on the detection section is detected based on changes in conductivity, capacitance, electrical resistance, etc., caused by deformation of the intermediate layer due to pressure application.

[0005] Furthermore, such surface pressure sensor sheets are generally made flexibly deformable as a whole so that they can accommodate various shapes of the pressure detection surface and can also accommodate partial pressure action. In particular, the detection section detects pressure by the deformation of the intermediate layer itself, so the entire detection section, including the first electrode and the second electrode, is generally made deformable. Furthermore, by making the detection section resilient, the surface pressure sensor sheet can be reused and used for re-detection, for example. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2018-112405 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-043881 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-181084 [Patent Document 4] Japanese Patent Application Laid-Open No. 2015-136620 Summary of the Invention [Problem to be solved by the invention]

[0007] However, after extensive research by the inventors into the surface pressure sensor sheet of the conventional structure described above, it was found that a new problem existed in that the detection accuracy decreased under certain conditions.

[0008] The researchers then discovered that this new problem is thought to be caused by the structure of conventional surface pressure sensor sheets. In other words, in conventional surface pressure sensor sheets, the entire detection section, including the first and second electrodes, is deformable. Therefore, when a large load is applied locally to a detection section, the first and second electrodes in the detection section are deformed so that they locally move closer to each other. As a result, the intermediate layer bottoms out locally or the amount of deformation increases locally, causing the elastic deformation characteristics of the entire detection section to become abnormal, which is thought to adversely affect the accuracy of load detection by the detection section.

[0009] Here, the present invention has been made based on the new findings obtained by the inventors in order to solve the aforementioned new problems inherent in surface pressure sensor sheets of conventional structures. [Means for solving the problem]

[0010] The following describes preferred embodiments for understanding the present invention, but the embodiments described below are merely examples and may be appropriately combined with one another. Multiple components described in each embodiment may be recognized and employed independently to the greatest extent possible, and may also be appropriately combined with any of the components described in other embodiments. Accordingly, the present invention is not limited to the embodiments described below, and various other embodiments may be realized.

[0011] The first aspect is a surface pressure sensor sheet that has a plurality of detection parts that elastically change shape in response to pressure applied from the outside, and each detection part has a first electrode and a second electrode arranged opposite each other so that pressure can be detected electrically, and in at least one of the plurality of detection parts, at least one of the first electrode and the second electrode has a reinforcing material located on the outer surface side opposite the inner surface side where the first electrode and the second electrode face each other, which suppresses local deformation of the detection part.

[0012] In the surface pressure sensor sheet constructed according to this aspect, the reinforcing material suppresses local deformation of the detection unit, and therefore when a large local load acts on the detection unit, the adverse effect on detection accuracy caused by the large local deformation of the detection unit is suppressed, thereby improving the detection accuracy of the input load. For example, when an uneven surface such as the occlusal surface of a tooth is pressed against the detection unit, the concentrated large load acting partially on the detection unit at the contact point of the convex portion of the uneven surface is dispersed over a wider area of ​​the detection unit via the reinforcing material, preventing the adverse effect on detection accuracy caused by local excessive proximity of the first electrode and the second electrode.

[0013] By arranging the reinforcing material on the outer surfaces of the first electrode and the second electrode, the outer surfaces, which are the input sides to the flexible first electrode and the second electrode, are protected by the reinforcing material, thereby preventing damage such as dents and cracks from occurring in the first electrode and the second electrode due to the action of local concentrated loads.

[0014] Since the reinforcing material is located on the outer surfaces of the first and second electrodes, the distance between the opposing surfaces of the first and second electrodes is prevented from being narrowed by the reinforcing material, and a large stroke in the direction in which the first and second electrodes approach each other is ensured. This allows a large amount of deformation of the detection unit in response to an input in the direction in which the first and second electrodes approach each other, and the electrical output associated with the deformation of the detection unit is large, thereby improving the accuracy of pressure detection.

[0015] In the second aspect, in the surface pressure sensor sheet described in the first aspect, the first electrodes and the second electrodes are formed in multiple numbers and extend in different directions, and the detection units are configured at multiple intersecting opposing points on the first electrodes and the second electrodes.

[0016] According to the surface pressure sensor sheet constructed in accordance with this embodiment, the desired number of detection sections can be constructed using a small number of first electrodes and second electrodes, and excellent pressure detection accuracy can be achieved with a simpler structure.

[0017] In a third aspect, in the surface pressure sensor sheet described in the first or second aspect, the detection unit has an elastic sensor layer disposed between the opposing first electrode and the opposing second electrode, and the sensor elastic layer is a dielectric layer, so that pressure exerted from the outside in the opposing direction of the first electrode and the second electrode is electrically detected based on a change in capacitance caused by a change in the opposing distance between the first electrode and the second electrode.

[0018] With the surface pressure sensor sheet constructed according to this aspect, the elasticity of the sensor elastic layer can also provide resistance to local input, thereby more effectively preventing a decrease in detection accuracy due to bottoming out. Furthermore, since the sensor elastic layer is a dielectric layer and the detection unit is a capacitance-type detection element, the surface pressure distribution can be measured efficiently. Furthermore, even if an elastically deformable sensor elastic layer is disposed between the opposing first and second electrodes, the pressure dispersion effect of the reinforcing material prevents the amount of elastic deformation of the sensor elastic layer from becoming locally excessive, thereby avoiding damage to the sensor elastic layer.

[0019] A fourth aspect is a surface pressure sensor sheet according to any one of the first to third aspects, wherein the reinforcing material is arranged on the outer surface side of each of the first electrode and the second electrode.

[0020] According to the surface pressure sensor sheet constructed in accordance with this embodiment, the first electrode and the second electrode are each protected by a reinforcing material arranged on each outer surface, thereby preventing damage such as dents and cracks caused by input to the first electrode and the second electrode.

[0021] For example, when measuring the occlusal force of teeth, even if both the contact surface facing the first electrode (one occlusal surface of the tooth) and the contact surface facing the second electrode (the other occlusal surface of the tooth) are uneven, the reinforcing material prevents local deformation of the detection unit on both sides of the opposing direction of the first and second electrodes, thereby more effectively preventing a decrease in detection accuracy due to large local deformation of the detection unit.

[0022] In a fifth aspect, in the surface pressure sensor sheet described in the fourth aspect, the reinforcing material arranged on the outer surface side of one of the first electrode and the second electrode is arranged so as to overlap the reinforcing material arranged on the outer surface side of the other electrode over the entire thickness direction of the sheet.

[0023] The reduction in detection accuracy due to local deformation of the detection unit is likely to be a problem, for example, when the detection unit is sandwiched between convex portions on both sides. With the surface pressure sensor sheet structured according to this aspect, the reinforcing materials arranged on both outer surfaces of the first electrode and the second electrode are arranged so as to overlap each other over the entire surface in the sheet thickness direction, which is the input direction. This prevents the detection unit from being partially excessively deformed and thus reducing detection accuracy, even if input occurs when the detection unit is sandwiched between convex portions at the parts where the reinforcing materials are arranged.

[0024] In a sixth aspect, in the surface pressure sensor sheet described in any one of the first to fifth aspects, the reinforcing material is of a size that does not reach another adjacent detection section, and is arranged so as not to overlap with the reinforcing material arranged in the other adjacent detection section.

[0025] According to the surface pressure sensor sheet having the structure according to this aspect, interference between adjacent reinforcing members and Since interference between the reinforcing material arranged in one detection unit and other detection units adjacent to that detection unit is prevented, interference from the reinforcing material can be prevented from affecting the pressure detection of the detection unit.

[0026] In a seventh aspect, in the surface pressure sensor sheet described in any one of the first to sixth aspects, a non-detection portion is provided around the detection portion in which the first electrode and the second electrode are not arranged opposite each other, and the reinforcing material is arranged to cover the entire detection portion and extend over the non-detection portion.

[0027] In the surface pressure sensor sheet constructed according to this aspect, the entire detection section is covered with the reinforcing material, so that large local deformations in the detection section are prevented by the pressure dispersion action of the reinforcing material. Also, a non-detection section that does not detect pressure is provided around the detection section, and even if the reinforcing material that covers the entire detection section extends to the periphery of the detection section, the extending portion of the reinforcing material is located above the non-detection section, so that it is unlikely to interfere with the adjacent detection section, and it is possible to prevent the reinforcing material from affecting pressure detection.

[0028] In an eighth aspect, in the surface pressure sensor sheet described in any one of the first to seventh aspects, the reinforcing material has a deformation strength greater than that of the first base sheet on which the first electrode is laminated and the second base sheet on which the second electrode is laminated.

[0029] In the surface pressure sensor sheet constructed according to this aspect, the first and second base sheets are flexible and have a smaller deformation strength than the reinforcing material, so that the detection section effectively deforms in response to an input, ensuring the pressure detection performance of the detection section. Also, the reinforcing material is harder and has a larger deformation strength than the first and second base sheets, so that the pressure dispersion effect in response to a local input can be effectively obtained.

[0030] In a ninth aspect, in the surface pressure sensor sheet described in any one of the first to eighth aspects, at least one of the plurality of detection sections is provided with a shape-restoring layer that is located outside the reinforcing material on the outer surface side of at least one of the first electrode and the second electrode and that elastically restores its shape when a load is applied and removed.

[0031] With the surface pressure sensor sheet constructed according to this aspect, when the uneven surface is pressed against the detection unit, the concave portions of the uneven surface are filled with the shape-restoring layer, further dispersing the pressure, thereby improving detection accuracy. In particular, the pressure dispersion effect of the shape-restoring layer alleviates the concentrated load acting on the reinforcing material, preventing damage such as dents in the reinforcing material due to excessive concentrated load.

[0032] Since the shape-restoring layer elastically restores its shape when a load is applied and removed, by arranging the shape-restoring layer on the outer surface side of the reinforcing material, when the surface pressure sensor sheet is used repeatedly, the shape-restoring layer can cover up any traces of deformation from the previous use.

[0033] In a tenth aspect, in the surface pressure sensor sheet described in the ninth aspect, the reinforcing material has a total area larger than the total area of ​​the plurality of detection sections, and the shape-restoring layer has a total area larger than the total area of ​​the reinforcing material, whereby the reinforcing material is arranged to cover all of the detection sections entirely, and the shape-restoring layer is arranged to cover all of the reinforcing materials entirely.

[0034] In a surface pressure sensor sheet constructed according to this embodiment, all detection parts are entirely covered with reinforcing material, and therefore the pressure dispersion action of the reinforcing material prevents a decrease in detection accuracy due to localized large input in any detection part, thereby realizing a surface pressure sensor sheet with high detection performance.

[0035] Furthermore, since all reinforcing materials are covered entirely with a shape-restoring layer, the pressure-dispersing action of the shape-restoring layer reduces damage such as dents and scratches in all reinforcing materials, and also covers up traces of deformation.

[0036] In an eleventh aspect, in the surface pressure sensor sheet described in the ninth or tenth aspect, the shape restoration layer is made of an elastic foam made of synthetic resin, and the shape restoration layer is provided on each outer surface side of the first electrode and the second electrode.

[0037] According to the surface pressure sensor sheet constructed in accordance with this embodiment, the shape restoration layer is made of an elastic foam made of synthetic resin, which provides excellent cushioning performance (pressure dispersion effect) and makes the shape restoration layer lightweight and easy to manufacture.

[0038] By providing a shape-restoring layer on each of the outer surfaces of the first electrode and the second electrode, it is possible to prevent, for example, traces of the reinforcing material or dents in the detection unit caused by use from being exposed to the outside on both sides of the surface pressure sensor sheet. In addition, it is possible to obtain the pressure dispersion effect of the shape-restoring layer on both sides of the surface pressure sensor sheet, which can further improve durability and pressure detection performance. [Effects of the Invention]

[0039] According to the present invention, it is possible to solve a new problem inherent in surface pressure sensor sheets of conventional structure, such as the adverse effect on the load detection accuracy by the detection unit when a large load is input locally to the detection unit. [Brief explanation of the drawings]

[0040] [Figure 1] FIG. 1 is a plan view showing an example of an occlusal force detection device equipped with an occlusal force sensor sheet according to a first embodiment of the present invention. [Figure 2A] FIG. 2 is an enlarged longitudinal cross-sectional view of a main part of the II-II cross section in FIG. 1, showing a pressure-sensing part in the measurement sheet portion. [Figure 2B] FIG. 2 is an enlarged longitudinal cross-sectional view of a main part of the II-II cross section in FIG. 1, showing a connection sheet portion; [Figure 3] FIG. 2 is a plan view of a first electrode sheet constituting the bite force sensor sheet shown in FIG. 1; [Figure 4] A plan view of a second electrode sheet constituting the bite force sensor sheet shown in Figure 1. [Figure 5] Plan view of the dielectric layer that constitutes the bite force sensor sheet shown in Figure 1. [Figure 6] Plan view of the guard layer that constitutes the bite force sensor sheet shown in Figure 1. [Figure 7] Plan view of the reinforcing film that constitutes the bite force sensor sheet shown in Figure 1 [Figure 8] FIG. 8 is an enlarged view of part VIII of FIG. 1. [Figure 9] Plan view of the shape restoring layer that constitutes the bite force sensor sheet shown in Figure 1. [Figure 10A] Graph showing the results of a load measurement test using the surface pressure sensor sheet according to the present invention. [Figure 10B] Graph showing the results of a load measurement test using a surface pressure sensor sheet with a conventional structure [Figure 10C] Graph showing the results of a load measurement test using another surface pressure sensor sheet according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0041] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0042] FIG. 1 shows an example of an occlusal force detection device 10. The occlusal force detection device 10 includes a occlusal force sensor sheet 12, which is a first embodiment of a surface pressure sensor sheet constructed according to the present invention, and a control device 14. The occlusal force detection device 10 detects the occlusal force caused by the occlusion of the upper and lower teeth of a subject (patient) using the occlusal force sensor sheet 12. In the following description, the up-down direction generally refers to the direction of the sensor thickness, i.e., the direction perpendicular to the plane of the paper in FIG. 1, in which a first electrode 24 and a second electrode 26 (described later) face each other. Similarly, the front-to-back direction refers to the up-to-down direction in FIG. 1, which is approximately the front-to-back direction of the patient during measurement, and the direction of insertion into the patient's oral cavity is defined as the front. Furthermore, the left-to-right direction refers to the left-to-right direction in FIG. 1, which is approximately the right-to-left direction of the patient during measurement.

[0043] More specifically, the bite force sensor sheet 12 is a flexible, thin sheet overall, and in this embodiment has a shape that spreads out flatly with a substantially uniform thickness. The bite force sensor sheet 12 comprises a sensor sheet main body 16, which comprises a measurement sheet portion 18 that is inserted into the oral cavity of the subject, and a connection sheet portion 20 that extends from the measurement sheet portion 18 to the outside of the oral cavity.

[0044] The measurement sheet portion 18 has a planar shape, such as an approximately arched or wide horseshoe shape, that roughly corresponds to the planar shape of the oral cavity so that it can be inserted into the oral cavity and spread out flat. On the other hand, the connecting sheet portion 20 has a roughly rectangular shape that extends outward by a predetermined width from the curved apex of the rear side of the measurement sheet portion 18 so as to protrude from the tip of the patient's mouth to the outside of the oral cavity.

[0045] The measurement sheet portion 18 is inserted into the oral cavity and occlusal contact between the upper and lower teeth, thereby having a pressure-sensing section 22 that electrically detects the pressure (occlusal force) exerted by occlusion. As shown in FIG. 2A , the pressure-sensing section 22 includes a pair of electrodes, a first electrode 24 and a second electrode 26, arranged opposite each other in the thickness direction of the sheet, sandwiching a dielectric layer 28 serving as a sensor elastic layer. In this embodiment, the pressure-sensing section 22 is the gray-shaded area in FIG. 1 , which corresponds to the array area of ​​the cellular detection sections 68 (described later), and includes gaps between adjacent detection sections 68 (non-detection sections 86, described later). Note that the thickness of the area is exaggerated in FIG. 2A and FIG. 2B (described later) for clarity.

[0046] In the measurement sheet portion 18, there is a peripheral area around the pressure-sensing portion 22 where the first electrode 24 and the second electrode 26 are not arranged opposite each other, and this peripheral area is a wiring portion 34 in which a first conductive wire 30 as a conductive wire conducted to the first electrode 24 and a second conductive wire 32 as a conductive wire conducted to the second electrode 26 are provided.

[0047] The first and second conductive wires 30, 32 provided in the measuring sheet portion 18 extend continuously from the measuring sheet portion 18 to the connecting sheet portion 20. The connecting sheet portion 20 is connected to the measuring sheet portion 18 at one end in the longitudinal direction extending forward and backward, and is provided at the other end in the longitudinal direction with a connector portion 36 connected to an electrical circuit on the control device 14 side. In short, the connecting sheet portion 20 has the connector portion 36 and a connecting portion 38 that connects the measuring sheet portion 18 and the connector portion 36, and the connector portion 36 is formed wider than the connecting portion 38.

[0048] That is, the first and second conductive wires 30, 32 are provided extending over substantially the entire length of the connection sheet portion 20. The connection ends of the first and second conductive wires 30, 32 extending from the measurement sheet portion 18 are exposed in the connector portion 36 and are detachably connected to the connector portion on the control device 14 side, thereby being electrically connected to an external electrical circuit on the control device 14 side.

[0049] In this embodiment, the measurement sheet portion 18 and the connection sheet portion 20 have a multi-layer structure throughout. Specifically, the sensor sheet main body 16 is formed with a laminated sheet structure in which a first electrode sheet 40 (see FIG. 3), a second electrode sheet 42 (see FIG. 4), a dielectric layer 28 (see FIG. 5), and a guard electrode layer 44 (see FIG. 6) are stacked together in the sheet thickness direction. In this embodiment, the first substrate sheet 46 and the second substrate sheet 58 (described later) in the first electrode sheet 40 and the second electrode sheet 42 are transparent members. For example, in FIGS. 1 and 4, the second electrodes 26 and the second conductive wires 32 are shown through the second substrate sheet 58. For ease of understanding, in FIG. 1, the first electrodes 24 and the first conductive wires 30 are shown through the second substrate sheet 58 and the dielectric layer 28. When the first electrode sheet 40 and the second electrode sheet 42 are overlapped in the sheet thickness direction, the first and second electrode sheets 40, 42 are overlapped in the orientations shown in Figures 3 and 4. The first electrode sheet 40 and the second electrode sheet 42 are each formed by a conventionally known printing method such as silk screen printing.

[0050] As shown in FIG. 3, the first electrode sheet 40 has a structure in which the first electrode 24 is formed on the upper surface of a first base sheet 46 having electrical insulation properties.

[0051] The first base sheet 46 is a flexible sheet made of rubber, synthetic resin, elastomer, or the like, and the front part 48a constituting the measurement sheet portion 18 is arch-shaped or horseshoe-shaped in plan view according to the tooth alignment, and the rear part 48b constituting the connection sheet portion 20 has a structure in which it extends straight backward by a predetermined width at the center of the left and right of the front part 48a.

[0052] The first electrodes 24 are formed on the surface of the first base sheet 46 using a conductive paint made of a rubber material or a synthetic resin material mixed with a conductive material such as carbon or silver, and are flexible enough to deform in accordance with the deformation of the first base sheet 46. The first electrodes 24 are generally rectangular in plan view and are arranged with their longitudinal axes in the left-right direction. In this embodiment, a plurality of first electrodes 24 are provided, with nine first electrodes 24 arranged in parallel in the front-rear direction. In the following description, the first electrodes 24 will be referred to as 24a, 24b,..., 24i from the rear, but will be simply referred to as the first electrodes 24 unless there is a need to distinguish between them.

[0053] The five rows of first electrodes 24e-24i on the front side each have a portion with a substantially constant width on both the left and right sides of a recess 50 provided at the front end of the first base sheet 46, and these substantially constant width portions on both sides are connected by connecting portions 52 with a smaller width. Each connecting portion 52 is provided so as to bypass the recess 50. As a result, although the five rows of first electrodes 24e-24i on the front side have separate substantially rectangular portions on both the left and right sides, the left and right portions are connected by the connecting portions 52, and thus each is formed as a single electrode. Furthermore, the four rows of first electrodes 24a-24d on the rear side do not have connecting portions 52 and extend substantially straight in the left-right direction with a constant width.

[0054] The width of the first electrodes 24 (the substantially rectangular portions on both the left and right sides of the first electrodes 24e-24i) is not particularly limited, but is set based on, for example, the size of the occlusal surface of a typical tooth, and is preferably 2 mm to 30 mm. Furthermore, it is preferable to make the distance between adjacent first electrodes 24, 24 in the width direction as small as possible, taking into account measurement errors, manufacturing errors, etc., and is preferably, for example, 0.025 mm to 5 mm.

[0055] Furthermore, first conductive wires 30 are electrically connected to the first electrodes 24. The first conductive wires 30 are formed in a laminated state on the first base sheet 46 using a conductive paint or the like, and are narrower than the first electrodes 24. The first conductive wires 30 extend substantially the entire length of the first electrodes 24 through the approximate center in the width direction of the first electrodes 24, thereby being electrically connected to the first electrodes 24. The first conductive wires 30 have the same flexibility as the first electrodes 24 and can follow the deformation of the first base sheet 46. Furthermore, as shown in FIG. 2A , in this embodiment, the first conductive wires 30 are provided on the lower surfaces of the first electrodes 24, but the first conductive wires 30 may also be formed on the upper surfaces of the first electrodes 24.

[0056] Each first conductive wire 30 extends continuously from one longitudinal end of the first electrode 24 to the other longitudinal end, bends rearward at the other longitudinal end, and extends rearward while curving along the side edge of the front portion 48a that constitutes the measurement sheet portion 18 of the first electrode sheet 40. In particular, a connecting portion 52 is provided in the longitudinal middle portion of each of the first electrodes 24e to 24i, and the first conductive wire 30 extends over the connecting portion 52 from one longitudinal end of each of the first electrodes 24e to 24i to the other longitudinal end. Each first conductive wire 30 extends rearward in a substantially straight line in the rear portion 48b that constitutes the connection sheet portion 20 of the first electrode sheet 40, and is connected to a first terminal 54 at its rear end, which is the connection end. That is, in this embodiment, one first conductive wire 30 is provided for each first electrode 24, and the multiple first conductive wires 30 are formed to extend approximately parallel to each other from each first electrode 24 to each first terminal 54.

[0057] Each first terminal 54 is exposed to the outside at the connector portion 36 of the connection sheet portion 20, and is configured to be electrically connected to an electrical circuit on the control device 14 when the bite force sensor sheet 12 is connected to the control device 14. The sides from which the first conductive wires 30 extend from each of the first electrodes 24a-24i are alternately set left and right for the first electrodes 24a-24i arranged in the front-rear direction. This allows the width of the wiring portion 34, which is a peripheral region provided around the pressure-sensitive portion 22 and in which the first conductive wires 30 are wired, to be set small while ensuring the distance between adjacent first conductive wires 30 on both the left and right sides. Furthermore, the first terminals 54 are exposed to the outside downward through through holes provided in the first base sheet 46, for example, but may also be exposed on the upper surface of the first base sheet 46.

[0058] The first electrode 24 and the first conductive wire 30 may be made of the same material, but in this embodiment, the first electrode 24 is made of conductive paint using a carbon filler, and the first conductive wire 30 is made of conductive paint using a silver paste. As a result, the wide first electrode 24 is made of an inexpensive material, and the narrow first conductive wire 30 is made of a material with lower electrical resistance.

[0059] Furthermore, a resist layer 56 made of an insulating synthetic resin is provided on the surface (upper surface) of the first electrode sheet 40. This resist layer 56 is provided so as to cover the first electrodes 24 and the first conductive wires 30, and the resist layer 56 is provided over the entire upper surface of the first electrode sheet 40. The resist layer 56 may be formed, for example, as a transparent or opaque layer. For example, a solder resist that is generally provided on printed circuit boards may be used as this resist layer 56. In particular, since the first electrode sheet 40 is flexible and deformable, the resist layer 56 is also formed flexibly and can deform in accordance with the deformation of the first electrode sheet 40.

[0060] In this embodiment, the resist layer 56 is provided over the entire surface of the first electrode sheet 40, and therefore the resist layer 56 is also provided in the portion of the first electrode sheet 40 that constitutes the wiring portion 34 in the measurement sheet portion 18. The resist layer 56 has a certain degree of strength, and can reinforce the first conductive wires 30 arranged in the wiring portion 34. The resist layer 56 is provided not only in the measurement sheet portion 18 but also in the connection sheet portion 20, and the resist layer 56 is also provided in the connector portion 36.

[0061] On the other hand, as shown in FIG. 4, the second electrode sheet 42 has a structure in which the second electrode 26 is disposed on the lower surface of a flexible second base sheet 58 having electrical insulation properties and made of rubber, synthetic resin, elastomer, or the like.

[0062] The second base sheet 58 has a shape that is generally the same as the first base sheet 46 overall, and the front portion 60a that constitutes the measurement sheet portion 18 is arch-shaped or horseshoe-shaped in plan view according to the tooth row, and the rear portion 60b that constitutes the connection sheet portion 20 has a structure that extends rearward at the center of the left and right of the front portion 60a.

[0063] Like the first electrode 24, the second electrode 26 is formed on the surface of the second substrate sheet 58 using a conductive paint made of a rubber or synthetic resin material mixed with a conductive material such as carbon or silver, and is flexible enough to conform to the deformation of the second substrate sheet 58. Furthermore, the second electrode 26 is generally rectangular in plan view and arranged with its longitudinal axis extending in the front-to-rear direction. In this embodiment, a plurality of second electrodes 26 are provided, with ten second electrodes 26 arranged in parallel in the left-to-right direction. In the following description, the second electrodes 26 will be referred to as 26a, 26b, . . . 26j from left to right, but will simply be referred to as the second electrodes 26 unless there is a need to distinguish them. The width and spacing of the second electrodes 26 may be set to be the same as those of the first electrodes 24, for example. However, in this embodiment, the width of the second electrodes 26 is smaller than that of the first electrodes 24.

[0064] Furthermore, a second conductive wire 32 is electrically connected to the second electrode 26. Like the first conductive wire 30, the second conductive wire 32 is formed on the surface of the second base sheet 58 using a conductive paint or the like, and has flexibility that allows it to follow the deformation of the second base sheet 58. The second conductive wire 32 in this embodiment is narrower than the second electrode 26 and is electrically connected to the second electrode 26 by extending in a laminated state over the second electrode 26. In this embodiment, the second electrode 26 is formed from a conductive paint using a carbon filler, like the first electrode 24, and the second conductive wire 32 is formed from a conductive paint using a silver paste, like the first conductive wire 30. Notably, in this embodiment, the second conductive wires 32 are provided on the upper surfaces of the second electrodes 26, but they may also be formed on the lower surfaces of the second electrodes 26.

[0065] In this embodiment, a total of ten second electrodes 26a-26j are provided in parallel at a predetermined distance from each other in the left-right direction, extending in the front-rear direction with a substantially constant width. The four second electrodes 26a-26d, 26g-26j on each side are inclined toward the center in the left-right direction toward the rear along the side edges of the front portion 60a of the second electrode sheet 42 that constitutes the measurement sheet portion 18, so as to avoid the central recess 50 on the left and right. The two second electrodes 26e, 26f at the center in the left-right direction extend straight in the front-rear direction behind the recess 50.

[0066] The second conductive wires 32 are located approximately at the center of the width direction (left-right direction) of each second electrode 26a-26j and extend the entire length of the second electrode 26a-26j. The second conductive wires 32 extend rearward from the rear end of each second electrode 26 and extend along the outer periphery of the front portion 60a to the rear portion 60b that constitutes the connecting sheet portion 20. In the rear portion 60b, the multiple second conductive wires 32 are parallel to each other and extend straight rearward. A second terminal 62 is connected to the rear end, which is the connecting end of each second conductive wire 32, and is exposed to the outside at the connector portion 36 of the connecting sheet portion 20. This allows each second terminal 62 to be electrically connected to an electrical circuit on the control device 14 when the bite force sensor sheet 12 is connected to the control device 14. The second terminals 62 may be exposed to the outside through a through-hole provided in the second base sheet 58, for example, or may be exposed on the underside of the second base sheet 58.

[0067] Furthermore, a resist layer 64 made of an insulating synthetic resin is provided on the surface (lower surface) of the second electrode sheet 42. Similar to the resist layer 56 on the first electrode sheet 40, this resist layer 64 is provided so as to cover the second electrodes 26 and the second conductive wires 32, and in this embodiment, the resist layer 64 is provided over the entire lower surface of the second electrode sheet 42. The resist layer 64 may be formed, for example, as a transparent or opaque layer. The resist layer 64 is provided so as to extend from the wiring portion 34 to the pressure-sensing portion 22. In particular, in this embodiment, the resist layer 64 is provided not only on the measurement sheet portion 18 but also on the connection sheet portion 20, and the resist layer 64 is also provided on the connector portion 36.

[0068] As shown in FIG. 2A , a dielectric layer 28 is disposed between the opposing surfaces of the first electrode sheet 40 and the second electrode sheet 42. The first electrode sheet 40 and the second electrode sheet 42 are stacked in the sheet thickness direction with the dielectric layer 28 sandwiched between them. The dielectric layer 28 is a sheet made of an electrically insulating material such as rubber or synthetic resin, and is capable of elastically compressive deformation in the vertical direction, i.e., the thickness direction. As shown in FIG. 5 , the dielectric layer 28 of this embodiment has a peripheral shape and size that generally corresponds to those of the first electrode sheet 40 and the second electrode sheet 42 in a plan view. The front portion 66a constituting the measurement sheet portion 18 is generally arch-shaped or horseshoe-shaped, and the rear portion 66b constituting the connection sheet portion 20 extends rearward from the center of the front portion 66a.

[0069] In this embodiment, the first electrode sheet 40, the second electrode sheet 42, and the dielectric layer 28 are overlapped over substantially the entire surfaces of the front portions 48a, 60a, and 66a that constitute the measurement sheet portion 18. That is, the dielectric layer 28 is overlapped not only over the pressure-sensing portion 22 in the measurement sheet portion 18 but also over the wiring portion 34 in the measurement sheet portion 18, extending continuously and entirely. Because the dielectric layer 28 has a certain degree of strength, it can reinforce the first and / or second conductive wires 30, 32 arranged in the wiring portion 34. Furthermore, the rear end of the dielectric layer 28 is located rearward of the measurement sheet portion 18, specifically near the connector portion 36, which is the middle portion of the connection portion 38 in the front-rear direction of the connection sheet portion 20. Therefore, the first and second conductive wires 30, 32 are also reinforced by the dielectric layer 28 in the connection sheet portion 20. In Figure 2B, in the portion behind the dielectric layer 28, the first electrode sheet 40 and the second electrode sheet 42 are spaced apart from each other in the vertical direction, but Figures 2A and 2B are model views of the longitudinal cross section of the bite force sensor sheet 12, and the first electrode sheet 40 and the second electrode sheet 42 do not need to be spaced apart from each other, for example, by being fixed to each other at the rear end.

[0070] The dielectric layer 28 is preferably a porous elastic body having a large number of bubbles, which allows for a large capacitance to be obtained in the detection unit 68 (described later) and reduces the Young's modulus in the thickness direction. Specifically, the dielectric layer 28 is formed from a foam of various synthetic resins such as polyurethane, polyethylene, polypropylene, etc.

[0071] The first electrode sheet 40 and the second electrode sheet 42 are stacked on top of each other with the dielectric layer 28 sandwiched between them. The first electrodes 24 of the first electrode sheet 40 and the second electrodes 26 of the second electrode sheet 42 extend in different directions, and as shown in FIGS. 1 and 2A , the first electrodes 24 and the second electrodes 26 are arranged to intersect and face each other with the dielectric layer 28 sandwiched between them. Each of the intersecting opposing portions of the first electrodes 24 (the first electrodes 24e to 24i are on both the left and right sides excluding the connecting portion 52) and the second electrodes 26 serves as a detection unit 68. In this embodiment, the first electrodes 24a to 24i extend substantially in the left-right direction, and the second electrodes 26a to 26j extend substantially in the front-rear direction. Furthermore, the first electrodes 24a to 24i and the second electrodes 26a to 26j have substantially the same width. As a result, a plurality of detection units 68 are formed, each having a substantially rectangular or diamond shape in plan view.

[0072] Each detection unit 68 has a dielectric layer 28 with a high dielectric constant disposed between opposing conductive first and second electrodes 24 and 26, thereby forming a capacitor. The detection unit 68 has a structure in which one of the first electrodes 24 and one of the second electrodes 26 are superimposed on each side of the dielectric layer 28 in the thickness direction. The dielectric layer 28 is allowed to undergo elastic compressive deformation in the opposing direction (vertical direction) of the first and second electrodes 24 and 26, allowing elastic shape change in the vertical direction due to external pressure. When a detection voltage is applied between the first and second electrodes 24 and 26, the distance between the opposing first and second electrodes 24 and 26 changes due to elastic deformation of the dielectric layer 28, thereby changing the capacitance of the detection unit 68. In this embodiment, the multiple detection units 68 are arranged in a generally wide U-shape that generally corresponds to the tooth row.

[0073] Preferably, the front-to-back and left-to-right dimensions of the detecting units 68 are each 4 mm to 10 mm. Preferably, a total of 4 to 256 detecting units 68 are provided. Furthermore, in the direction orthogonal to the tooth row, particularly in the front-to-back direction in the portion corresponding to the front teeth at the center and in the left-to-right direction in the portions corresponding to the back teeth at both sides, it is preferable that four or more detecting units 68 are arranged side by side, and it is preferable that the effective width of the detecting area in which the detecting units 68 are arranged is 20 mm or more in both the front-to-back direction at the center and the left-to-right direction at both sides.

[0074] A guard electrode layer 44 is superimposed on the surface (lower surface) of the first electrode sheet 40 opposite to the surface superimposed on the dielectric layer 28. As shown in FIG. 6 , the guard electrode layer 44 has a structure in which a guard electrode 72 is formed on the upper surface of a flexible third base sheet 70 that has the same shape and is made of the same material as the first and second base sheets 46, 58. The guard electrode 72 is made of a conductive material and is flexible, like the first and second electrodes 24, 26, and has a shape that covers substantially the entirety of the multiple detecting portions 68 when projected in the vertical direction. That is, in this embodiment, the guard electrode 72 is substantially U-shaped.

[0075] Furthermore, a ground wiring 74 connected to the guard electrode 72 is formed on the guard electrode layer 44 in a laminated state superimposed on the third base sheet 70. This ground wiring 74 is electrically connected to the guard electrode 72, extends rearward from the guard electrode 72, and is connected to a ground terminal 76 provided at the rear end of the third base sheet 70. The ground wiring 74 is preferably made of a material having a lower electrical resistance than the guard electrode 72, and is also formed on the guard electrode 72. In this embodiment, a resist layer 78 similar to the resist layers 56, 64 is also provided on the guard electrode layer 44, and the resist layer 78 is provided over the entire surface (upper surface) of the guard electrode layer 44.

[0076] Furthermore, a reinforcing sheet 80 is superimposed and fixed to the connector portion 36 of the bite force sensor sheet 12. In this embodiment, as shown in FIG. 2B , the reinforcing sheet 80 is superimposed and fixed to the outer surface (upper surface) of the rear end portion of the second base sheet 58, covering the first terminal 54, the second terminal 62, and the ground terminal 76 in a plan view and partially overlapping the dielectric layer 28 in the front-to-rear direction. The reinforcing sheet 80 has a shape substantially similar to the rear ends of the first and second electrode sheets 40, 42 and is preferably made of a hard synthetic resin having greater strength than the first and second base sheets 46, 58, etc. In this embodiment, since the control device 14 is connected to the connector portion 36, the reinforcing sheet 80 is made of an insulating synthetic resin. By providing such a reinforcing sheet 80, the second conductive wires 32 provided on the second electrode sheet 42 can be reinforced in the connector portion 36 of the connection sheet portion 20. Furthermore, the reinforcing sheet 80 overlaps the dielectric layer 28 in the front-rear direction, and reinforces the first conductive wires 30 provided on the first electrode sheet 40 via the dielectric layer 28 .

[0077] In this embodiment, the dielectric layer 28 is provided from the measurement sheet portion 18 of the bite force sensor sheet 12 to the front-rear middle portion of the connection portion 38 of the connection sheet portion 20, and the reinforcing sheet 80 is provided from the front-rear middle portion of the connection portion 38 to the connector portion 36, and the dielectric layer 28 and the reinforcing sheet 80 overlap each other. Therefore, the first and second conductive wires 30, 32 can be reinforced over the entire length of the bite force sensor sheet 12 by the dielectric layer 28 and the reinforcing sheet 80. In addition, the concentration of strain and stress at the boundary portion between the dielectric layer 28 and the reinforcing sheet 80 is also alleviated.

[0078] The sensor sheet main body 16 of this embodiment is configured by stacking and bonding the first electrode sheet 40, second electrode sheet 42, dielectric layer 28, guard electrode layer 44, and reinforcing sheet 80 as described above. The first electrode sheet 40, second electrode sheet 42, dielectric layer 28, guard electrode layer 44, and reinforcing sheet 80 can be bonded by a conventionally known method, such as adhesive or welding. In this embodiment, for example, a hard holding member 82 can be attached to the rear end of the sensor sheet main body 16 to sandwich and bond the first electrode sheet 40, second electrode sheet 42, guard electrode layer 44, and reinforcing sheet 80 from both the top and bottom. By connecting this holding member 82 to the control device 14, the first terminal 54, second terminal 62, and ground terminal 76 of the connector portion 36 are electrically connected to the control device 14. For example, in FIG. 2B , the internal space formed between the opposing surfaces of the upper and lower resist layers 56, 64 may be opened rearward at the connector portion 36, and the first and second conductive wires 30, 32 may be exposed to the internal space through through-holes provided in each of the resist layers 56, 64, so that connection terminals formed in the connector portion on the control device 14 side can be inserted into the internal space to establish electrical continuity with the first and second conductive wires 30, 32.

[0079] 1, the connector portion 36 of the bite force sensor sheet 12 is connected to the control device 14. For example, the first terminal 54, the second terminal 62, and the ground terminal 76 located on the connector portion 36 are connected to the control device 14. By connecting the ground terminal 76 to the control device 14, the guard electrode 72 may be grounded and maintained at a reference potential. Furthermore, the control device 14 may include a power supply device connected to the first and second electrodes 24, 26 by the first and second conductive wires 30, 32 and applying a voltage for capacitance measurement between the first electrode 24 and the second electrode 26, a detection means for detecting the amount of change in capacitance in each detection unit 68, and an bite force calculation means for calculating the bite force based on the capacitance detection result by the detection means.

[0080] As shown in Fig. 2A, a reinforcing material 84 is attached in a laminated state to the measurement sheet portion 18 of the sensor sheet main body 16. The reinforcing material 84 is in the form of a sheet or film, and may be made of metal, but is preferably made of a synthetic resin material such as polyethylene terephthalate (PET). Because the reinforcing material 84 is overlaid on the measurement sheet portion 18 that is inserted into the oral cavity, it is desirably thin, with a thickness of, for example, 1 mm or less.

[0081] The reinforcing material 84 has a hardness, as determined by an indentation hardness test, that is harder than any of the first base sheet 46, the second base sheet 58, the third base sheet 70, and the dielectric layer 28, and has greater deformation strength against the action of an indentation force in the thickness direction, making it less likely to undergo deformation such as bending or denting due to the action of the indentation force. More preferably, the reinforcing material 84 is a hard member that has greater deformation strength against the indentation force than any of the first electrode sheet 40, the second electrode sheet 42, the guard electrode layer 44, and the dielectric layer 28. Furthermore, the reinforcing material 84 has a greater deformation strength against a compressive force in the vertical direction than the detection unit 68, and even if the reinforcing material 84 is disposed in a layered state on the outer surface of the detection unit 68, the effect of compressive deformation of the reinforcing material 84 on the measured biting force is substantially negligible.

[0082] In this embodiment, the reinforcing material 84 is thicker than the first base sheet 46 and the second base sheet 58. As a result, even if the reinforcing material 84 is made of the same material as the first and second base sheets 46, 58, the deformation strength of the reinforcing material 84 is greater than that of the first and second base sheets 46, 58. The hardness (deformation strength) of the reinforcing material 84 can be set appropriately depending on the material and the shape, such as the thickness dimension.

[0083] 2A , the reinforcing material 84 is superimposed on the upper and lower outer sides of the detection section 68 of the sensor sheet main body 16, and is disposed on the outer surface opposite to the inner surface on which the first electrode 24 and the second electrode 26 face each other. In the present embodiment, the reinforcing material 84 is disposed on each of the outer surface sides of the first electrode 24 and the second electrode 26. More specifically, the reinforcing material 84 is disposed below the first base sheet 46 to which the first electrode 24 is fixed and the guard electrode layer 44, and is fixed to the lower surface of the third base sheet 70 and to the upper surface of the second base sheet 58 to which the second electrode 26 is fixed. In the following description, the reinforcing film disposed on the outer surface side (upper side) of the second electrode 26 may be referred to as reinforcing material 84a, and the reinforcing film disposed on the outer surface side (lower side) of the first electrode 24 may be referred to as reinforcing material 84b.

[0084] 7, a plurality of reinforcing members 84 are arranged side by side on substantially the same plane, and have a shape in plan view that generally corresponds to the pressure-sensitive section 22 of the sensor sheet main body 16 as a whole. Each of the plurality of reinforcing members 84 has a planar shape that corresponds to one of the detecting sections 68. In this embodiment, since the planar shape of the detecting section 68 is generally rectangular or rhombic, the planar shape of each reinforcing member 84 is also generally rectangular or rhombic. The plurality of reinforcing members 84 are arranged in a U-shaped area in plan view that generally corresponds to the arrangement area of ​​the detecting sections 68 in the measurement sheet portion 18.

[0085] As shown in Fig. 8, each reinforcing member 84 is preferably slightly larger than the detection portion 68 in a plan view, and as also shown in Fig. 2A, it covers the entire outer surface of each detection portion 68 in the thickness direction and protrudes radially outward beyond the detection portion 68. Non-detection portions 86, in which the first electrode 24 and the second electrode 26 are not arranged opposite each other, are provided between adjacent detection portions 68, 68, and the reinforcing members 84 that protrude radially outward beyond the detection portion 68 extend into the non-detection portions 86. Therefore, the total area of ​​the reinforcing members 84 is larger than the total area of ​​the upper and lower outer surfaces of the detection portion 68. For example, the total area of ​​the reinforcing members 84 is greater than 100% and less than or equal to 110% of the total area of ​​the upper and lower outer surfaces of the detection portion 68.

[0086] The reinforcing material 84 covering the outer surface of each detecting portion 68 is sized so as not to extend over adjacent detecting portions 68, and does not overlap other detecting portions 68 in the vertical direction. Adjacent reinforcing materials 84, 84 extend into the non-detecting portions 86, do not overlap each other in the thickness direction, and are slightly spaced apart in the planar direction. Therefore, each reinforcing material 84 can be displaced independently in the thickness direction, and is less likely to affect the detection of input by each detecting portion 68. For ease of viewing, in FIG. 8 , the outline of the reinforcing material 84 is indicated by a solid line, the outline of the first and second electrodes 24, 26 is indicated by a dashed line, and the outline of the first and second conductive wires 30, 32 is indicated by a dashed line.

[0087] The reinforcing member 84a provided above the detecting portion 68 and the reinforcing member 84b provided below the detecting portion 68 have substantially the same shape and size, and are arranged so as to overlap substantially entirely in the vertical direction. However, the upper reinforcing member 84a and the lower reinforcing member 84b may have different shapes and sizes, and do not necessarily have to overlap entirely in the vertical direction.

[0088] The reinforcing material 84 has, for example, an adhesive layer on one side, and is fixed to the sensor sheet main body 16 by being attached by the adhesive layer to the outer surface of the second base sheet 58 or the third base sheet 70 that constitutes the outermost surface of the measurement sheet portion 18. Note that multiple reinforcing materials 84 arranged on the base sheet as shown in FIG. 7 can also be attached simultaneously to the surfaces of multiple detecting sections 68. The multiple reinforcing materials 84 can be formed in a pre-arranged state on the base sheet, for example, by cutting a resin sheet attached to the base sheet with a laser or the like.

[0089] By disposing relatively hard reinforcing members 84 on the outer surface side of each detecting portion 68, pressure that is concentrated in the surface direction on the reinforcing members 84 is dispersed in the surface direction and transmitted to the detecting portions 68, thereby suppressing local deformation of the detecting portions 68 in response to input in the vertical direction. In other words, when a compressive force in the vertical direction is partially input to the detecting portions 68 in a plan view, the compressive force transmitted to the detecting portions 68 via the reinforcing members 84 is dispersed over a wide range in a plan view by the hard reinforcing members 84 and applied to the detecting portions 68. Therefore, even a spot-like input acts on the detecting portions 68 as a surface pressure, suppressing large local deformation of the detecting portions 68 and causing compressive deformation over a wider range or across the entire detecting portion 68.

[0090] As shown in FIG. 2A , a shape-restoring layer 88 is provided on the outer side of the reinforcing member 84. The shape-restoring layer 88 is a spongy member made of, for example, an elastic foam made of synthetic resin. The shape-restoring layer 88 is easily deformed under load and has the elasticity to quickly restore its original shape when the load is removed. The shape-restoring layer 88 is sheet-shaped, but is thicker than the reinforcing member 84 and the first and second electrodes 24, 26, allowing for a large amount of compressive deformation in the thickness direction. As shown in FIG. 9 , the shape-restoring layer 88 is shaped to cover substantially the entire pressure-sensing section 22 in the measurement sheet portion 18 in plan view, and includes recesses 90 corresponding to the recesses 50 in the measurement sheet portion 18. In this embodiment, two shape-restoring layers 88a, 88b are overlapped on both the upper and lower outer sides of the reinforcing members 84a, 84b on both the upper and lower sides. The entire upper surfaces of all of the reinforcing materials 84a arranged on the upper surface side are covered by a single shape-restoring layer 88a, and the entire lower surfaces of all of the reinforcing materials 84b arranged on the lower surface side are covered by a single shape-restoring layer 88b. In this embodiment, the shape-restoring layer 88 is provided to extend outward from the reinforcing materials 84, and the area of ​​the shape-restoring layer 88 is larger than the total area of ​​the reinforcing materials 84. The shape-restoring layer 88 is fixed to the upper and lower outer surfaces of the reinforcing materials 84, for example, by adhesive tape having adhesive layers on both sides (double-sided tape), adhesive, or the like.

[0091] A waterproof cover 92, as shown imaginarily in FIG. 1 by a two-dot chain line, is preferably attached to the measurement sheet portion 18 of the sensor sheet main body 16, to which the reinforcing material 84 and the shape-restoring layer 88 are attached. The waterproof cover 92 is made of a synthetic resin material that is water-resistant to prevent water from passing through, corrosion-resistant to the oral environment, and harmless to the human body when placed in the oral cavity. Specifically, the waterproof cover 92 is formed into a bag shape by welding upper and lower plastic films to each other at three edges (front and left and right) of the outer periphery, and is designed to be detachably placed over the measurement sheet portion 18 from the front. A recess 94 corresponding to the recess 50 of the measurement sheet portion 18 is provided in the center of the front end of the waterproof cover 92 in the lateral direction. The waterproof cover 92 of this embodiment is designed to cover not only the measurement sheet portion 18 including the first and second electrodes 24 and 26, but also the connection sheet portion 20 and the control device 14. However, the waterproof cover 92 may cover only the measurement sheet portion 18 having the first and second electrodes 24, 26, or may have a structure that covers the measurement sheet portion 18 and the connection sheet portion 20 but does not cover the control device 14. Furthermore, the waterproof cover 92 is easily detachable from the measurement sheet portion 18, and for example, after removing the measurement sheet portion 18 covered with the waterproof cover 92 from the oral cavity of the subject, the waterproof cover 92 can be replaced with a new one, allowing the bite force sensor sheet 12 to be easily reused while keeping the measurement sheet portion 18 clean.

[0092] Below, we will explain a specific example of a method for detecting the occlusal force of a subject using the occlusal force detection device 10 equipped with the occlusal force sensor sheet 12 of this embodiment. Note that the occlusal force detection method is not limited to the method described below.

[0093] First, the first and second terminals 54, 62 and the ground terminal 76 of the bite force sensor sheet 12 are connected to the control device 14, and the waterproof cover 92 is attached to the measurement sheet portion 18. Next, the control device 14 is turned on, and the power supply of the control device 14 starts applying a detection voltage between the first and second electrodes 24, 26, and the detection means of the control device 14 starts detecting the capacitance of each detection unit 68, and the bite force calculation means starts calculating the bite force based on the capacitance value detected by the detection means.

[0094] Then, the measurement sheet portion 18 of the bite force sensor sheet 12 is inserted between the upper and lower teeth in the oral cavity of the person to be detected, and the U-shaped arranged detection units 68 are held in a position corresponding to the tooth row of the person to be detected. The positioning of the bite force sensor sheet 12 can be achieved, for example, by a protrusion protruding from the surface of the measurement sheet portion 18, or a guide such as a scale or mark printed on the upper surface of the second base sheet 58.

[0095] The bite force sensor sheet 12 is inserted into the oral cavity of the subject with the guard electrode layer 44 facing closer to the tongue of the subject than the first and second electrode sheets 40, 42. This reduces noise caused by the tongue of the subject coming into contact with the measurement sheet portion 18 by the guard electrode 72, improving detection accuracy.

[0096] Next, the subject is instructed to bite down on the bite force sensor sheet 12, and the bite force of the subject is applied to the pressure-sensitive portion 22 of the bite force sensor sheet 12. When the subject bites down on the pressure-sensitive portion 22 of the bite force sensor sheet 12, the dielectric layer 28 of the pressure-sensitive portion 22 is compressed vertically between the upper and lower teeth of the subject, and the first electrode 24 and the second electrode 26, which are provided on either the upper or lower sides of the dielectric layer 28, are displaced closer to each other as the dielectric layer 28 elastically deforms in response to the applied bite force. As a result, in the detection portion 68 on which the bite force is applied, the capacitance increases in accordance with the magnitude of the applied bite force, and the applied bite force is electrically detected.

[0097] The change in capacitance of the detection units 68 is detected by a detection means in the control device 14, and the change in capacitance detected by the detection means is calculated as the occlusal force acting on each detection unit 68 by an occlusal force calculation means in the control device 14. The occlusal force calculated in this manner is displayed, for example, on a monitor connected to the control device 14, thereby allowing the occlusal force detection device 10 to detect the occlusal force. That is, the occlusal force acting in the opposing direction of the pair of electrodes (first and second electrodes 24, 26) is detected based on the change in capacitance due to the change in the opposing distance between the pair of electrodes (first and second electrodes 24, 26). Note that the content of the occlusal force measurement results displayed on the monitor is not particularly limited, and examples that can be used include a distribution chart showing the distribution of occlusal forces using colors or shading, a numerical value of the sum of occlusal forces detected by each detection unit 68, and a graph showing the change in the sum of occlusal forces over time.

[0098] The bite force sensor sheet 12 of this embodiment, configured as described above, can measure the bite force of the subject with greater accuracy. Because the bite surfaces of the teeth are uneven, when the subject bites the bite force sensor sheet 12, the convex portions of the bite surfaces of the teeth press strongly against the sheet in localized areas. By providing reinforcing members 84 on the upper and lower outer sides of the detection unit 68, the localized load caused by the contact of the convex portions of the bite surfaces of the teeth is dispersed by the reinforcing members 84 and transmitted to the detection unit 68. This prevents damage to the flexible detection unit 68 from the input of a large localized load. Furthermore, the distributed load acts to compress and deform a wide area or the entire dielectric layer 28, preventing bottoming out, in which the local deformation of the dielectric layer 28 due to the input reaches its deformation tolerance. This is believed to reduce errors in the detection results due to bottoming out.

[0099] In this embodiment, since the reinforcing members 84 are provided on both the upper and lower outer sides of the detecting portion 68, when the detecting portion 68 is bitten and pressed against the occlusal surfaces of the upper and lower teeth, the input load is dispersed on both the upper and lower surfaces of the detecting portion 68 via the reinforcing members 84. Therefore, even when the detecting portion 68 is sandwiched between the convex portions of the occlusal surfaces of the upper teeth (maxillary teeth) and the convex portions of the occlusal surfaces of the lower teeth (mandibular teeth), for example, and a large local load acts on the detecting portion 68 between the upper and lower convex portions, the load dispersion effect of the reinforcing members 84a, 84b on both the upper and lower sides prevents large local deformation of the detecting portion 68.

[0100] Furthermore, because the reinforcing material 84 is disposed on the upper and lower outer surfaces of the detecting portion 68 (the lower surface facing the first electrode 24 and the upper surface facing the second electrode 26), the effective length of the dielectric layer 28 in the vertical direction can be prevented from being shortened by the provision of the reinforcing material 84. This improves the detection accuracy of occlusal force, etc., and ensures a wide range of magnitudes over which occlusal force, etc. can be accurately detected. In particular, even when the reinforcing material 84 is made relatively thick to ensure its deformation strength against external forces, the reinforcing material 84 is disposed on the outside of the detecting portion 68, so that the detection performance of the detecting portion is unlikely to be affected.

[0101] The reinforcement member 84 is larger than the upper and lower outer surfaces of the detection portion 68 in a plan view, covers the entire upper and lower outer surfaces of the detection portion 68, and extends beyond the detection portion 68 to the non-detection portion 86 on the periphery. This allows the occlusal surface of the tooth to be more reliably pressed indirectly against the detection portion 68 via the reinforcement member 84, and the occlusal force is distributed across the entire detection portion 68. This effectively prevents a decrease in detection accuracy that would be caused by bottoming out, and advantageously improves the durability of the detection portion 68. Furthermore, when the convex portion of the occlusal surface of the tooth is positioned on the non-detection portion 86, the convex portion of the occlusal surface is pressed against the reinforcement member 84 that extends beyond the non-detection portion 86, and input from the convex portion of the occlusal surface can be applied to the detection portion 68 via the reinforcement member 84. As a result, occlusal force detection errors caused by the convex portion of the occlusal surface being pressed against the non-detection portion 86 are reduced, enabling stable, highly accurate detection (measurement) of occlusal force.

[0102] Adjacent reinforcing members 84, 84 that extend into the non-detection portions 86 between the detecting portions 68, 68 do not overlap in the vertical direction and are spaced apart in the planar direction. This prevents interference between adjacent reinforcing members 84, 84 from affecting the input to a detecting portion 68 covered by one reinforcing member 84 on the detection results of another detecting portion 68 covered by the other reinforcing member 84. This makes it possible for each detecting portion 68 to detect a load independently, making it possible, for example, to grasp the load distribution with high precision.

[0103] The reinforcing material 84 may be hard enough to not deform due to occlusal force. However, in this embodiment, the reinforcing material 84 is formed of a thin synthetic resin and is hard enough to be dented or broken due to occlusal force. By making the reinforcing material 84 hard enough to be deformed by an expected input load (here, occlusal force), for example, when the subject bites the pressure-sensing unit 22 to which the reinforcing material 84 is fixed, the subject can bite the pressure-sensing unit 22 with all their strength without hesitation due to the excessively hard feel of the reinforcing material 84, thereby enabling stable measurement of the subject's maximum occlusal force. Furthermore, interference between the reinforcing materials 84 is unlikely to restrict the deformation of the measurement sheet portion 18, and the measurement sheet portion 18 supporting the reinforcing material 84 can be easily inserted into the oral cavity by, for example, bending it as needed.

[0104] Furthermore, because shape-restoring layers 88 are provided on the upper and lower outer sides of the reinforcing member 84, even if the reinforcing member 84 is bent, dented, discolored, or the like due to the action of occlusal force, the reinforcing member 84 is covered by the shape-restoring layer 88, making the crease difficult to see from the outside. Therefore, when the bite force sensor sheet 12 is used repeatedly, it is unlikely to cause discomfort to the subject due to reuse, and it is expected that resistance to insertion into the oral cavity will be reduced. Furthermore, when the bite force sensor sheet 12 is bitten, the flexibly deforming shape-restoring layer 88 deforms to fill recesses on the occlusal surfaces of the teeth, thereby further dispersing the load input from the occlusal surfaces of the teeth to the detection unit 68 and more effectively preventing large localized deformation of the detection unit 68. In particular, because the load acting on the reinforcing member 84 is dispersed by the shape-restoring layer 88, the reinforcing member 84 is less likely to be dented, broken, or the like.

[0105] The shape restoring layer 88 is provided over an area larger than the total area of ​​all of the reinforcing materials 84, and is provided so as to entirely cover all of the reinforcing materials 84. Therefore, the above-mentioned effect obtained by covering the reinforcing materials 84 with the shape restoring layer 88 is effectively exerted over the entirety of all of the reinforcing materials 84.

[0106] In this embodiment, the shape restoring layers 88 are provided on both the upper and lower outer sides of the upper and lower reinforcing members 84. This allows the shape restoring layers 88 to cover and hide dents and other imperfections that occur due to use in the upper and lower reinforcing members 84, and also distributes the load caused by deformation of the shape restoring layers 88.

[0107] FIG. 10A shows the results of a load detection experiment using the surface pressure sensor sheet according to the present invention, and FIG. 10B shows the results of a load detection experiment using a surface pressure sensor sheet with a conventional structure. In this experiment, the pressure-sensitive portion of each surface pressure sensor sheet was positioned so that it could occlude a dentition model (an upper and lower jaw with teeth) that resembled human teeth. A test load equivalent to occlusal force was input from the dentition model to each surface pressure sensor sheet, and it was confirmed whether the load value (detected load value) detected by the surface pressure sensor sheet matched the test load value. The surface pressure sensor sheet according to the present invention used in the experiment in FIG. 10A and the surface pressure sensor sheet with a conventional structure used in the experiment in FIG. 10B differed only in the presence or absence of a reinforcing material and a shape-restoring layer; the shape, size, material, and other components were identical. Furthermore, the same dentition model and the unevenness of the occlusal surface were used in both the detection experiments in FIG. 10A and FIG. 10B.

[0108] 10A shows that the load detection experiment results using the surface pressure sensor sheet according to the present invention, shown by the solid line, match with extremely high accuracy the test load value shown by the dashed line. In particular, even in the latter half of the experiment when the test load value was increased, the detected load value of the surface pressure sensor sheet and the test load value matched with high accuracy. This confirmed through the experiment that even if a large local load is input to the detection section of the surface pressure sensor sheet, a decrease in detection accuracy, which is presumably due to bottoming out of the dielectric layer, is unlikely to occur.

[0109] On the other hand, the experimental results of load detection using a surface pressure sensor sheet with a conventional structure shown in Figure 10B reveal a larger deviation between the detected load value of the surface pressure sensor sheet, shown by the solid line, and the test load value, shown by the dashed line, than the experimental results in Figure 10A. In particular, in the latter half of the experiment, when the test load value was increased, the detected load value of the surface pressure sensor sheet became smaller than the test load value. This is thought to be due to the fact that the increase in the test load acting locally on the detection section of the surface pressure sensor sheet caused the dielectric layer to locally crush at that detection section. In other words, bottoming out occurred, where the compressive deformation of the dielectric layer due to the input reached its maximum deformation tolerance, and further approach between the electrodes was restricted at the bottoming out point. This can be interpreted as a result of a smaller change in capacitance value, causing the detected load value of the surface pressure sensor sheet to become smaller than the test load value that it should normally be.

[0110] As described above, it is clear from the experimental results of FIGS. 10A and 10B that the surface pressure sensor sheet according to the present invention can detect input load more accurately than surface pressure sensor sheets of conventional structures.

[0111] 10C shows the results of a similar experiment using a surface pressure sensor sheet with a structure in which the shape-restoring layer has been removed from the surface pressure sensor sheet according to the present invention shown in FIG. 10A. The experimental results for the surface pressure sensor sheet according to the present invention shown in FIG. 10C also show that the detected load value of the surface pressure sensor sheet more accurately matches the test load value compared to the case shown in FIG. 10B, which used a surface pressure sensor sheet with a conventional structure. Thus, even a surface pressure sensor sheet with a structure including a reinforcing material but no shape-restoring layer can prevent bottoming out of the detection unit and achieve highly accurate detection. However, the experimental results in FIG. 10A show that the detected load value of the surface pressure sensor sheet more accurately follows the test load value compared to the experimental results in FIG. 10C, confirming that the shape-restoring layer can also contribute to improving detection accuracy.

[0112] A similar load detection experiment was conducted using a dental model in which the tooth that detected the maximum pressure (occlusal force) in the experiments shown in Figures 10A and 10B was removed. As a result, the error in the detected load value of the surface pressure sensor sheet according to the present invention relative to the test load value was almost unchanged from that shown in Figure 10A. This is because, with the surface pressure sensor sheet according to the present invention, bottoming out did not occur even at the location where the maximum pressure was detected in the detection experiment that yielded the results shown in Figure 10A , and it is presumed that removing the tooth with the maximum pressure hardly affected the detection accuracy. On the other hand, the error in the detected load value of the surface pressure sensor sheet with the conventional structure relative to the test load value was smaller than that shown in Figure 10B. This is because, with the surface pressure sensor sheet with the conventional structure, bottoming out occurred at the location where the maximum pressure was detected in the detection experiment that yielded the results shown in Figure 10B , and this bottoming out at that location resulted in an error between the detected load value and the test load value. However, removing the tooth that detected the maximum pressure eliminated the bottoming out at that tooth, which is presumably confirming an improvement in detection accuracy compared to the detection result shown in Figure 10B.

[0113] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the specific descriptions. For example, in the above-described embodiments, the reinforcing members 84 are provided on both the upper and lower sides of the detection unit 68. However, the reinforcing members 84 may be provided on only one side of the detection unit 68, either the upper or lower side.

[0114] Although the reinforcing material preferably covers the entire surface of the detection unit 68, it can also be provided so as to partially cover the detection unit 68. For example, taking into account the unevenness of the occlusal surface of the teeth, the reinforcing material can be partially provided on at least one of the upper and lower surfaces of the detection unit 68 in a portion where the convex portion of the occlusal surface of the teeth is expected to press. Therefore, the reinforcing material does not necessarily need to be larger than the detection unit 68 when viewed in the vertical direction (plan view), and is not limited to a structure that protrudes outward from the detection unit 68. Furthermore, for example, the reinforcing material can be made mesh-like or have through holes formed in the reinforcing material, so that the reinforcing material protrudes outward from the detection unit 68 and partially covers the detection unit 68. Note that when the reinforcing material is provided so as to partially cover the detection unit 68, the area of ​​the reinforcing material is preferably 50% or more of the area of ​​the detection unit 68 covered by the reinforcing material, so that 50% or more of the area of ​​the detection unit 68 is covered by the reinforcing material. As a result, for example, when measuring the occlusal force of teeth, the occlusal surface of the teeth is less likely to be pressed against the detection unit 68 at a position where the reinforcing material is removed, and the provision of the reinforcing material can effectively achieve effects such as improved detection accuracy.

[0115] The reinforcing material may be provided across multiple detection units 68. For example, when only the total value of occlusal force is required, a reinforcing material disposed across all detection units 68 may be used, or when the oral cavity is roughly divided into multiple regions, such as the back tooth region and the front tooth region, and the occlusal force of each region is to be determined, a reinforcing material continuous across the detection units 68 in each region may be used.

[0116] The shape restoring layer 88 is not limited to a spongy porous body, and may be made of, for example, a solid elastic body, as long as it can ensure ease of deformation when a load is applied and shape restoration when the load is removed.

[0117] In the above embodiment, the shape restoration layer 88 was provided on the outer surface of the upper and lower reinforcement materials 84a, 84b on both the upper and lower sides of the detection unit 68, but the shape restoration layer may be provided only on the outer surface of either the upper or lower reinforcement material.

[0118] In the above embodiment, an example was shown in which one shape restoring layer 88 was provided on each of the upper and lower sides, but for example, the shape restoring layer may be composed of a plurality of shape restoring bodies divided in the plane direction, and for example, the shape restoring layer may be composed of a plurality of shape restoring bodies having shapes and sizes corresponding to the reinforcing members 84 and arranged in the same manner as the reinforcing members 84. In this case, it is desirable that each shape restoring body be arranged to entirely cover the reinforcing member 84, and that the total area of ​​the shape restoring layer, which is the total area of ​​the shape restoring bodies, be equal to or greater than the total area of ​​the reinforcing members 84.

[0119] The shape-restoring layer does not need to cover the surfaces of all the reinforcement members; for example, it can be provided only on the surfaces of selected reinforcement members that are expected to receive particularly large input loads. Therefore, the total area of ​​the shape-restoring layer can be smaller than the total area of ​​all the reinforcement members. The shape-restoring layer is not essential and can be omitted. In this case, for example, by using a waterproof cover 92 that is opaque or translucent, which reduces visibility of the interior, dents in the reinforcement members due to frequent use can be covered even without the shape-restoring layer.

[0120] When the reinforcing material 84 is provided on only one of the outer surfaces of the detection section 68, a shape recovery layer 88 can be provided on the outer surface where the reinforcing material 84 is provided, and a buffer layer similar to the shape recovery layer can also be provided on the outer surface where the reinforcing material 84 is not provided.

[0121] In the above embodiment, the bite force sensor sheet 12 as a surface pressure sensor sheet was a capacitance type, but this is not limited to this. That is, the surface pressure sensor sheet of the present invention may be any flexible sheet capable of detecting force as an electrical signal. In addition to the capacitance type as in the above embodiment, it may be a piezoelectric type in which a piezoelectric layer is disposed between opposing surfaces of a pair of electrodes to detect force as an electrical signal based on a change in voltage, or a resistive type in which an elastically deformable resistive layer such as conductive rubber is disposed between opposing surfaces of a pair of electrodes to detect force as an electrical signal based on a change in electrical resistance. In the case of a surface pressure sensor sheet other than a capacitance type, the dielectric layer is not essential, and a piezoelectric layer or resistive layer made of an elastic material may be provided as the sensor elastic layer. Furthermore, in a capacitance type bite force sensor sheet 12, the dielectric layer may be formed of an air layer, as shown in, for example, JP 2012-181084 A.

[0122] A guide may be provided to position the bite force sensor sheet 12 in the oral cavity. The guide may protrude upward from the second electrode sheet 42 and abut against, for example, the upper front teeth or upper lip to achieve positioning, or it may protrude downward from the first electrode sheet 40 and abut against, for example, the lower front teeth or lower lip to achieve positioning. By providing such a guide, when the bite force sensor sheet 12 is inserted into the patient's oral cavity, the patient's front teeth or lip abut against the guide, restricting further insertion of the bite force sensor sheet 12 and making the approximate center position recognizable through touch or vision. As a result, the patient can consciously or objectively, for example, position the bite force sensor sheet 12 appropriately in the oral cavity. From this position, the patient can bite down on the bite force sensor sheet 12 without it coming off the pressure-sensing portion 22, thereby applying a stable bite force to the pressure-sensing portion 22. Such guides are not limited to those that protrude outward in the vertical direction, but may be scales, marks, printed marks, etc. that indicate the position of the bite force sensor sheet in the oral cavity. Furthermore, guides may be provided on both the top and bottom of the bite force sensor sheet, and for example, two of the guides exemplified above may be used in combination.

[0123] The arrangement of the first and second electrodes is not limited to that exemplified in the above embodiment. For example, if it is not necessary to grasp the distribution of occlusal force, only one detection unit may be provided in the pressure-sensing unit. This allows, for example, the occlusal force of a specific tooth to be selectively detected by one detection unit. In this case, the first and second substrate sheets may be, for example, straight strip-shaped, and only one first and one second electrode are provided. However, by providing one first and one second electrode each with a curved shape corresponding to the tooth row, it is also possible to detect the occlusal force of the entire tooth row with one detection unit.

[0124] Furthermore, when a plurality of first electrodes are provided, the plurality of first electrodes do not necessarily have to have the same width, and may have different widths depending on, for example, the size of the teeth with which they are to come into contact. Similarly, a plurality of types of second electrodes with different widths may be employed.

[0125] Furthermore, the first electrode and the second electrode may be, for example, circular or square, provided in a spot-like shape in a plan view. Similarly, the shape of the detection unit is not limited to the rectangular or diamond shape exemplified in the above embodiment. Furthermore, the planar shape of the reinforcing material covering the upper and lower outer surfaces of each detection unit can be appropriately selected depending on the shape of the detection unit.

[0126] In the above embodiment, the first electrodes 24e to 24i are provided with a connecting portion 52 in their left-right intermediate portions, and both left and right sides are connected by the connecting portion 52, thereby forming each of the first electrodes 24e to 24i as a single electrode. However, this is not limited to such an embodiment. That is, the first electrodes 24e to 24i may be formed as a single electrode by connecting both left and right sides with first conductive wires 30 provided on the first electrodes 24e to 24i without providing the connecting portion 52. Note that the left and right sides of the first electrodes 24e to 24i in the above embodiment may be connected to separate first conductive wires 30, respectively, to form separate electrodes independent of each other. In this case, the connecting portion 52 and the first conductive wires 30 in the left-right intermediate portions connecting both left and right sides of the first electrodes 24e to 24i are not necessary.

[0127] The surface pressure sensor sheet according to the present invention is not necessarily used only for detecting the occlusal force of teeth, but can be widely used for detecting surface pressure. In particular, the surface pressure sensor sheet according to the present invention is suitably applied when, for example, the surface to be detected for surface pressure has irregularities and the protrusions of the detection surface can be pressed locally (partially in the surface direction) against the detection unit. [Explanation of symbols]

[0128] 10. Bite force detection device 12 Bite force sensor sheet (surface pressure sensor sheet) 14 Control device 16 Sensor sheet body 18 Measurement sheet part 20 Connection sheet part 22 Pressure-sensing part 24 First electrode 26 Second electrode 28 Dielectric Layer 30 First conductive wire 32 Second conductive wire 34 Wiring section 36 Connector part 38 Connection 40 First electrode sheet 42 Second electrode sheet 44 Guard electrode layer 46 First base sheet 48a Front part 48b rear part 50 recess 52 Connecting part 54 First terminal 56 Resist layer 58 Second base sheet 60a front part 60b rear part 62 Second terminal 64 resist layer 66a Front part 66b rear part 68 Detector 70 Third base sheet 72 Guard electrode 74 Ground wiring 76 Ground terminal 78 Resist layer 80 Reinforcement sheet 82 Retaining member 84 Reinforcement 86 Non-detection part 88 Shape recovery layer 90 recess 92 Waterproof cover

Claims

1. A bite force sensor sheet is provided with a plurality of detection sections that elastically change shape in response to an external bite force caused by the bite of teeth, and each detection section has a first electrode and a second electrode arranged opposite each other so that pressure can be electrically detected. A bite force sensor sheet in which, in at least one of the multiple detection sections, at least one of the first electrode and the second electrode is provided with a reinforcing material located on the outer surface opposite the inner surface where the first electrode and the second electrode face each other, to suppress local deformation of the detection section.

2. The bite force sensor sheet of claim 1, wherein the first electrodes and the second electrodes are formed in multiple lines extending in different directions, and the detection units are configured at multiple intersecting opposing points on the first electrodes and the second electrodes.

3. 3. The bite force sensor sheet according to claim 1, wherein the detection section has an elastically deformable sensor elastic layer disposed between the opposing first electrode and the opposing second electrode, and the sensor elastic layer is a dielectric layer, so that pressure exerted from the outside in the opposing direction of the first electrode and the second electrode is electrically detected based on a change in capacitance caused by a change in the opposing distance between the first electrode and the second electrode.

4. The bite force sensor sheet according to any one of claims 1 to 3, wherein the reinforcing material is disposed on each outer surface side of the first electrode and the second electrode.

5. 5. The bite force sensor sheet according to claim 4, wherein the reinforcing material arranged on the outer surface of one of the first electrode and the second electrode is arranged so as to overlap the reinforcing material arranged on the outer surface of the other electrode over the entire thickness of the sheet.

6. A bite force sensor sheet as described in any one of claims 1 to 5, wherein the reinforcing material is of a size that does not reach another adjacent detection section, and is arranged so as not to overlap with the reinforcing material arranged in the other adjacent detection section.

7. A bite force sensor sheet as described in any one of claims 1 to 6, wherein a non-detection portion in which the first electrode and the second electrode are not arranged opposite each other is provided around the detection portion, and the reinforcing material covers the entire detection portion and extends into the non-detection portion.

8. A bite force sensor sheet as described in any one of claims 1 to 7, wherein the reinforcing material has a deformation strength greater than that of the first substrate sheet on which the first electrode is laminated and the second substrate sheet on which the second electrode is laminated.

9. A bite force sensor sheet as described in any one of claims 1 to 8, wherein in at least one of the plurality of detection sections, a shape restoring layer is provided on the outer surface side of at least one of the first electrode and the second electrode, located outside the reinforcing material, and which elastically restores its shape when a load is applied and removed.

10. the reinforcing member has a total area greater than a total area of ​​the plurality of detection portions, the shape-restoring layer has a total area greater than a total area of ​​the reinforcing material; As a result, the reinforcing material is arranged to cover the entire surface of each detection section, and the shape restoring layer is arranged to cover the entire surface of each reinforcing material. This is the bite force sensor sheet described in claim 9.

11. The shape-restoring layer is made of an elastic foam made of synthetic resin, The bite force sensor sheet according to claim 9 or 10, wherein the shape restoring layer is provided on each outer surface of the first electrode and the second electrode.

12. the bite force sensor sheet has a measurement sheet portion that is inserted into the oral cavity and a connection sheet portion that extends from the measurement sheet portion to the outside of the oral cavity, the connecting sheet portion is formed in a rectangular shape extending outward from the center in the left-right direction of the measuring sheet portion, The measurement sheet portion is provided with a wiring portion in which conductive lines are arranged and are electrically connected to the electrodes and extend to the connection sheet portion, and the wiring portion is provided with a resist layer superimposed on the conductive lines, The bite force sensor sheet according to any one of claims 1 to 11, wherein the resist layer is also provided in the connection sheet portion, superimposed on the conductive wire extending from the wiring portion in the connection sheet portion.

13. the bite force sensor sheet has a measurement sheet portion that is inserted into the oral cavity and a connection sheet portion that extends from the measurement sheet portion to the outside of the oral cavity, The measurement sheet portion is provided with a wiring portion in which conductive lines are arranged and are electrically connected to the electrodes and extend to the connection sheet portion, and the wiring portion is provided with a resist layer superimposed on the conductive lines, A dielectric layer elastically deformable in the sheet thickness direction is disposed between the opposing surfaces of a pair of electrodes consisting of the first electrode and the second electrode that constitute each of the detection units, and the bite force exerted in the opposing direction of the pair of electrodes is detected based on a change in capacitance caused by a change in the opposing distance of the pair of electrodes, and a flexible first electrode sheet on which one of the pair of electrodes and the conductive wire conducted to that electrode are formed, and a flexible second electrode sheet on which the other of the pair of electrodes and the conductive wire conducted to that electrode are formed are overlapped in the sheet thickness direction with the dielectric layer sandwiched between them, and The bite force sensor sheet according to any one of claims 1 to 12, wherein the resist layer is provided on at least one of the first electrode sheet and the second electrode sheet so as to cover the electrodes and the conductive wires.

14. The bite force sensor sheet according to claim 12 or 13, wherein the wiring portions are provided so as to extend along both left and right edge portions of the measurement sheet portion.

15. The bite force sensor sheet according to any one of claims 1 to 14, wherein the detection portions are configured at intervals of 5 mm or less.

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