JP6454439B1 - Pressure sensor - Google Patents

Abstract

An object of the present invention is to reduce the thickness and to increase the detection area while suppressing drift, to further increase durability, and to detect pressure or load continuously. A pressure sensor is provided. A pressure-sensitive sensor includes an upper electrode and a lower electrode facing the upper electrode with a space therebetween. The upper electrode 11 includes an upper comb tooth portion 22 that is a pair of comb-shaped members facing each other, and a frame portion 21 that connects one end of each tooth portion 23 of the upper comb tooth portion 22. The tooth portion 22 is bent toward the lower electrode 12 side. The lower electrode 12 is formed of a semiconductive resistor and has a lower comb tooth portion 31 that is a pair of comb-tooth shaped members provided at a position facing the upper comb tooth portion 22. [Selection] Figure 6

Description

  The present invention relates to a pressure-sensitive sensor whose resistance value changes according to pressure or load.

  As a pressure-sensitive sensor whose resistance value (electrical resistance value) changes according to pressure or load, a sensor in which a pressure-sensitive resistor formed of resin is provided between electrodes is disclosed in Patent Document 1. In this pressure-sensitive sensor, when pressure or a load is applied to the electrode, the contact area between the electrode and the pressure-sensitive resistor changes, and the resistance value changes accordingly.

  Patent Document 2 discloses a variable resistance switch in which a metal plate having both ends fixed to a push button so as to be bent in a U shape is opposed to a planar metal plate. In this variable resistance switch, when pressure or a load is applied to the push button, the short-circuit distance at which each metal plate is short-circuited changes, and the resistance value changes accordingly.

  Patent Document 3 discloses a switch device in which one end of a linear elastic member is fixed to a push button and the other end is brought into contact with a fixed contact arranged in parallel on a substrate. In this switch device, when pressure or a load is applied to the push button, the number of fixing members that come into contact with the elastic member changes, and ON / OFF is detected stepwise according to the number.

JP 2000-82608 A Japanese Utility Model Publication No. 61-77520 Japanese Utility Model Publication No. 5-34621

  In the pressure-sensitive sensor described in Patent Document 1, a resin having a hardness lower than that of a metal or the like is used as a material of the pressure-sensitive resistor. Therefore, when pressure or a load is continuously applied, the pressure-sensitive resistor becomes time-consuming. As a result, a phenomenon called drift occurs in which the resistance value changes with time.

  In the variable resistance switch described in Patent Document 2, both sides of the lowest point of the U-shaped bent metal plate are in contact with the flat metal plate substantially evenly, so that the change in the short-circuit distance with respect to pressure or load is large. The change in resistance value with respect to pressure or load becomes large. For this reason, if the resistance change range in which the resistance value changes is widened and an attempt is made to widen the detection area for detecting pressure or load, the size is increased. In particular, as the thickness is reduced, the change in the short-circuit distance with respect to the pressure or load increases, so that it is difficult to reduce the thickness while suppressing the increase in size.

  In the switch device described in Patent Document 3, since only one end of the linear elastic member is fixed to the push button, the load relating to the push button is biased, and as a result, the push button may be galled. There is a problem with durability. Moreover, since ON / OFF is detected according to the number of the fixing members that come into contact with the elastic member, the change in the detection value becomes stepwise. Therefore, there is also a problem that pressure or load cannot be detected continuously.

  The present invention has been made in view of the above problems, and it is possible to increase the thickness of a thin film and the detection area while suppressing an increase in size while suppressing drift, and has high durability, and An object of the present invention is to provide a pressure-sensitive sensor capable of continuously detecting pressure or load.

  The pressure-sensitive sensor according to the present invention is a pressure-sensitive sensor having an upper electrode and a lower electrode facing the upper electrode with a space therebetween, and the upper electrode is a pair of comb-shaped members facing each other. An upper comb tooth portion and a frame portion connecting one end of each tooth portion of the upper comb tooth portion, the upper comb tooth portion is bent toward the lower electrode side, and the lower electrode is The lower comb-tooth part which is a pair of comb-tooth shaped member provided in the position facing the said upper comb-tooth part is formed with a semiconductive resistor.

  According to the present invention, it is possible to reduce the film thickness and increase the detection area while suppressing the increase in size while suppressing the drift, and further, the durability is high, and the pressure or load is continuously detected. It is possible.

It is a perspective view which shows the pressure sensor of the 1st Embodiment of this invention. It is a see-through | perspective top view which shows the pressure sensor of the 1st Embodiment of this invention. FIG. 3 is a longitudinal sectional view taken along line SS in FIGS. 1 and 2. It is a perspective view which shows the structure of the upper electrode of the 1st Embodiment of this invention. It is a top view which shows the structure of the upper electrode of the 1st Embodiment of this invention. It is a figure for demonstrating operation | movement of the pressure-sensitive sensor of the 1st Embodiment of this invention. It is a top view which shows the structure of the upper electrode of the 2nd Embodiment of this invention. It is a perspective view which shows the structure of the upper electrode of the 3rd Embodiment of this invention. It is a longitudinal cross-sectional view which shows the structure of the pressure sensitive sensor of the 5th Embodiment of this invention. It is a disassembled perspective view which shows the structure of the upper part of the pressure-sensitive sensor of the 5th Embodiment of this invention. It is a longitudinal cross-sectional view which shows the structure of the pressure sensitive sensor of the 6th Embodiment of this invention. It is a disassembled perspective view which shows the structure of the upper part of the pressure sensitive sensor of the 6th Embodiment of this invention. It is a figure for demonstrating operation | movement of the pressure sensor of the 6th Embodiment of this invention. It is a longitudinal cross-sectional view which shows the pressure sensor of other embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, in each drawing, the same code | symbol is attached | subjected to what has the same function, and the description may be abbreviate | omitted.

(First embodiment)
FIG. 1 is a perspective view showing a pressure-sensitive sensor according to the first embodiment of the present invention, FIG. 2 is a perspective top view showing the pressure-sensitive sensor according to the first embodiment of the present invention, and FIG. FIG. 3 is a longitudinal sectional view taken along line SS in FIGS. 1 and 2.

  The pressure-sensitive sensor 100 shown in FIGS. 1 to 3 has a configuration in which an upper substrate 1 and a lower substrate 2 face each other with a spacer 3 therebetween. In FIG. 2, a configuration excluding the upper substrate 1 is shown.

  The upper substrate 1 and the lower substrate 2 are formed of an insulating material. The spacer 3 is not particularly limited as long as it is a member that allows a desired gap between the upper substrate 1 and the lower substrate 2. Hereinafter, in order to simplify the description, the pressure or load applied to the pressure-sensitive sensor 100 is simply referred to as a load.

  On the upper surface of the upper substrate 1 (surface opposite to the surface facing the lower substrate 2), a convex portion 1a that functions as a push button for applying a load to the pressure sensor 100 is provided. The convex portion 1a is desirably provided in the central portion of the upper substrate 1. The upper substrate 1 may be formed in a flat plate shape without including the convex portion 1a.

  In the illustrated example, the upper substrate 1 has a rectangular shape. The lower substrate 2 has a rectangular first portion 2a facing the upper substrate 1, and a second portion 2b extending outward from the first portion 2a. As shown in FIG. 2, the spacer 3 is disposed along the first portion 2 a of the lower substrate 2 and the outer periphery of the upper substrate 1. The spacer 3 is provided with one gap 3a, and the second portion 2b of the lower substrate 2 extends outward from the place where the gap 3a of the spacer 3 is provided.

  An upper electrode 11 is provided on the lower surface of the upper substrate 1 (surface facing the lower substrate 2), and a lower electrode 12 is provided on the upper surface of the lower substrate 2 (surface facing the upper substrate 1). The upper electrode 11 and the lower electrode 12 are provided in a portion surrounded by the spacer 3. The upper electrode 11 and the lower electrode 12 are provided so as to face each other. In the present embodiment, the upper electrode 11 and the lower electrode 12 are not in contact with each other and face each other with a space therebetween when no load is applied to the pressure sensor 100. They may be provided so as to be in contact with each other in a state where no is applied. FIG. 3 shows the pressure-sensitive sensor 100 in a no-load state in which no load is applied to the pressure-sensitive sensor 100. In FIG. 2, the upper electrode 11 is not shown.

  FIG. 4 is a perspective view showing the configuration of the upper electrode 11, and FIG. 5 is a top view showing the configuration of the upper electrode 11. The upper electrode 11 shown in FIGS. 4 and 5 is formed of a rectangular frame portion 21 and an upper comb tooth portion 22 that is a pair of comb-tooth shaped members facing each other. The pair of upper comb teeth 22 extends from each of the pair of opposite sides of the frame portion 21 in a direction facing each other (in a direction toward the inside of the frame portion 21). Accordingly, one end of each tooth portion 23 of the pair of upper comb teeth portions 22 is connected by the frame portion 21. In the present embodiment, each tooth portion 23 of the upper comb tooth portion 22 is formed of a plate member having a rectangular shape when viewed from above (Z direction), and is provided substantially parallel to each other.

  The pair of upper comb teeth 22 are inserted into each other. That is, the pair of upper comb teeth 22 is formed such that the tooth portion 23 of one upper comb tooth 22 enters the recess 24 of the other upper comb tooth 22. Therefore, the tooth part 23 of one upper comb tooth part 22 and the tooth part 23 of the other upper comb tooth part 22 intersect with the Y direction which is the extending direction in which the tooth part 23 extends (more specifically, It is formed to be adjacent in the X direction (substantially orthogonal). In addition, the recessed part 24 shows the space of the both sides of each tooth | gear part 23. FIG.

  The tooth portion 23 of the upper comb tooth portion 22 is bent toward the lower electrode 12 at or near the root portion 25 connected to the frame portion 21. Thereby, the upper comb-tooth portion 22 is bent toward the lower electrode 12 and is inclined toward the lower electrode 12 from the root portion 25 toward the tip portion 26. The bending angle (inclination angle) of the tooth portion 23 is preferably 0.1 ° to 10 °. In the present embodiment, the bending angle is approximately 3 °. In the present embodiment, the tooth portion 23 has a linear shape when viewed from the side.

  The number of teeth 23 may be two or more for the entire pair of upper comb teeth 22, and preferably three or more. In the present embodiment, the number of the tooth portions 23 is two for each of the pair of upper comb teeth portions 22, that is, four for the entire pair of upper comb teeth portions 22. Hereinafter, the number of teeth 23 represents the number of teeth 23 in the entire pair of upper comb teeth 22 unless otherwise specified.

  The upper electrode 11, that is, the frame portion 21 and the upper comb tooth portion 22 described above is formed of a conductive elastic body that is a conductive elastic body. Therefore, each tooth portion 23 of the upper comb tooth portion 22 is electrically connected via the frame portion 21. The frame portion 21 and the upper comb tooth portion 22 are desirably integrally formed as illustrated, but the separately formed frame portion 21 and the upper comb tooth portion 22 may be joined. In that case, a joining means is not specifically limited, For example, it is welding, screwing, etc. Further, when the frame portion 21 and the upper comb tooth portion 22 are formed separately, the frame portion 21 and the upper comb tooth portion 22 are preferably formed of the same material, but are formed of different materials. Also good. Moreover, as long as each tooth part 23 of the upper comb-tooth part 22 can be connected and electrically connected, other members, such as a U-shaped frame part, may be used instead of the rectangular frame part 21. .

As shown in FIG. 2, the lower electrode 12 is a lower part that is a comb-like member having a plurality of tooth portions 32 provided at positions facing each tooth portion 23 of the upper comb tooth portion 22 of the upper electrode 11. A comb tooth portion 31 is provided. Since the upper comb-tooth portion 22 is provided in a pair facing each other, the lower comb-tooth portion 31 is also composed of a pair of members facing each other. The lower comb tooth portion 31 is formed of a semiconductive resistor. The line resistivity of the lower comb tooth portion 31 is desirably 10 Ω / mm to 10 ⁴ Ω / mm. The line resistivity indicates a resistance value per unit length.

  Each tooth 32 of the pair of lower comb teeth 31 is electrically connected by a conductive wire 33. Specifically, as the conductive wire 33, the conductive wire that electrically connects each tooth portion 32 of one lower comb tooth portion 31 and the respective tooth portion 32 of the other lower comb tooth portion 31 are electrically connected. There is a conductive line to be. The conductive line 33 is provided on the lower substrate 2, extends from the gap 3a of the spacer 3 along the second portion 2b of the lower substrate 2, and a connection terminal 33a is formed at the end thereof. The connection terminal 33 a is electrically connected to an external device (not shown), and when the pressure sensor 100 is driven, a voltage is applied from the external device to the lower electrode 12 through the connection terminal 33 a and the conductive wire 33.

  FIG. 6 is a diagram for explaining the operation of the pressure-sensitive sensor 100. In FIG. 6, the transparent side surface of the pressure-sensitive sensor 100 in a no-load state where no load is applied to the pressure-sensitive sensor 100, a weak-load state where a weak load is applied, and a strong-load state where a strong load is applied. A figure and a perspective top view are shown. In FIG. 6, the number of tooth portions of the upper comb tooth portion 22 (lower comb tooth portion 31) is two for simplification of description.

  When no load is applied to the pressure-sensitive sensor 100, in this embodiment, as shown in FIG. 6A, the upper comb teeth 22 of the upper electrode 11 and the lower comb of the lower electrode 12 are used. The tooth portions 31 are formed so as not to contact each other. For this reason, the resistance value of the pressure-sensitive sensor 100 is infinite.

  In a light load state where a weak load F1 is applied to the convex portion 1a of the upper substrate 1 of the pressure sensor 100, the upper substrate 1 bends according to the load F1, and accordingly, the upper comb tooth portion 22 of the upper electrode 11 is deformed. As shown in FIG. 6B, the lower comb teeth 31 of the lower electrode 12 come into contact. At this time, since the upper comb tooth portion 22 is inclined toward the lower electrode 12 from the root portion 25 toward the tip portion 26, the upper comb tooth portion 22 contacts the lower comb tooth portion 31 from the tip portion 26. The effective distances, which are the distances from the connecting portion between the tooth portion 32 and the conductive wire 33 to the contact portion between the tooth portion 32 and the upper comb tooth portion 22, in each tooth portion 32 of the lower comb tooth portion 31, are respectively A and B. Then, the pressure-sensitive sensor 100 has a resistance value R (A + B) corresponding to the sum A + B of the effective distances A and B.

  Furthermore, when the load F2 larger than the load F1 shown in FIG. 6B is a strong load state where the convex portion 1a of the upper substrate 1 is applied, the upper substrate 1 is further bent as shown in FIG. 6C. . Thereby, the length (the length in the Y direction in which the tooth portion 23 extends) where the upper comb tooth portion 22 and the lower comb tooth portion 31 are in contact with each other becomes longer than in the case of FIG. For this reason, when the effective distances in the tooth portions 32 of the lower comb tooth portion 31 are a and b, the sum of the effective distances a + b is more than the sum A + B of the effective distances in the lightly loaded state shown in FIG. Is also shortened. For this reason, the resistance value R (a + b) of the pressure-sensitive sensor 100 corresponding to the sum of the effective distances a and b is smaller than the resistance value R (A + B) of the pressure-sensitive sensor 100 in a light load state.

  Therefore, in the pressure-sensitive sensor 100, the resistance value changes according to the applied load. At this time, since the effective distance changes continuously according to the applied load, the resistance value also changes continuously according to the load. In addition, the resistance value of the pressure sensor 100 is actually a value obtained by adding the resistance value corresponding to the above-described effective distance and the resistance value of the upper electrode 11 or the conductive wire 33. Here, the description is simplified. Therefore, since the resistance values of the upper electrode 11 and the conductive wire 33 are constant, it is regarded as zero.

  In the pressure-sensitive sensor 100 having the above-described configuration, the upper electrode 11 is made of a hard material that can reduce drift, a thickness that is suitable for repeated use (deformation), and a low value that is suitable for changing the resistance value of the pressure-sensitive sensor 100. It is desirable to have a resistance value or the like. Specifically, the material of the upper electrode 11 is preferably a conductive metal plate for a leaf spring, or a metal or resin plate coated with a conductive paint, and the tensile strength of the upper electrode 11 is 70 MPa or more. Is preferably 0.1 mm to 1 mm and the volume resistivity is 10 μΩm or less.

  The number of teeth 23 is preferably 3 or more. This is because when the load is applied, the balance of the load applied to each tooth portion 23 is good, and the position where the load is applied deviates from the central portion of the upper substrate 1, and as a result, the load This is because even when the load direction in which the pressure is applied deviates from the Z direction (direction orthogonal to the pressure-sensitive sensor 100), variation in resistance value change in each tooth portion 23 is reduced. From the viewpoint of the balance of the load, the larger the number of teeth 23 is, the better.

The width W _D of the tooth portion 32 of the lower comb tooth portion 31 is preferably wider than the width W _U of teeth 23 of the upper comb tooth portion 22. This is because when a load is applied to the pressure-sensitive sensor 100, even if a positional deviation occurs in the in-plane direction of the pressure-sensitive sensor 100 between the tooth portion 32 and the tooth portion 23 (direction in the XY plane), This is because the upper electrode 11 and the lower electrode 12 can be more reliably contacted.

  As described above, according to the present embodiment, the upper electrode 11 includes the upper comb tooth portion 22 which is a pair of comb-shaped members facing each other, and one end of each tooth portion 23 of the upper comb tooth portion 22. The upper comb tooth portion 22 is bent toward the lower electrode 12 side. The lower electrode 12 is formed of a semiconductive resistor and has a lower comb tooth portion 31 that is a pair of comb-tooth shaped members provided at a position facing the upper comb tooth portion 22.

  By having the said structure, since it becomes unnecessary to provide a pressure-sensitive resistor etc. with low hardness between the upper electrode 11 and the lower electrode 12, it becomes possible to suppress a drift. Moreover, since the upper comb-tooth part 22 is the structure bent to the lower electrode 12 side, when a load is applied, since the one side of the upper comb-tooth part 22 and the lower comb-tooth part 31 contact, It becomes possible to reduce the change in the short-circuit distance, and it is possible to reduce the thickness and increase the size while suppressing the increase in size. Moreover, since the upper comb-tooth part 22 has a pair of structure which mutually opposes, it becomes possible to equalize the load concerning the upper board | substrate 1 which supports the upper comb-tooth part 22. FIG. For this reason, generation | occurrence | production of a galling etc. can be suppressed and durability can be made high. Furthermore, since the contact distance between the upper comb tooth portion 22 and the lower comb tooth portion 31 can be continuously changed according to the load, the load can be detected continuously.

  Therefore, in the pressure-sensitive sensor 100 of the present embodiment, it is possible to increase the thickness and the detection area while suppressing the increase in size while suppressing the drift, and further, the durability is high and the pressure or load is increased. Can be continuously detected.

  Moreover, in this embodiment, since a pair of upper comb-tooth part 22 has mutually entered, it becomes possible to further suppress enlargement.

  Moreover, in this embodiment, the pressure-sensitive sensor 100 has the frame part 21 which connects a pair of upper comb-tooth part 22, and a pair of upper comb-tooth part 22 and the frame part 21 are integrally formed. . For this reason, it becomes possible to easily produce the upper electrode 11 having high durability.

Further, in the present embodiment, the width W _D of the tooth portion 32 of the lower comb tooth portion 31, since wider than the width W _U of teeth 23 of the upper comb tooth portion 22, contact between the upper electrode 11 and lower electrode 12 Can be performed more reliably. Moreover, since the number of the tooth parts 23 of the upper comb tooth part 22 is three or more, it becomes possible to reduce the variation in resistance value change.

(Second Embodiment)
FIG. 7 is a top view showing the configuration of the upper electrode 11a of the pressure-sensitive sensor 100 according to the second embodiment of the present invention. The upper electrode 11a shown in FIG. 7 is different from the upper electrode 11 of the first embodiment shown in FIG. 5 in that a tooth portion 23a is provided instead of the tooth portion 23 of the upper comb tooth portion 22. In addition, the other structure of the pressure-sensitive sensor 100 of this embodiment is the same as that of 1st Embodiment.

The tooth portion 23 in the first embodiment shown in FIG. 5 has a rectangular shape, but the tooth portion 23 a shown in FIG. 7 has a distal end portion 26 that is thinner than the root portion 25. More specifically, the tooth portion 23a is formed in a substantially triangular shape whose width gradually decreases from the root portion 25 toward the distal end portion 26 when viewed from above. The width W _D of the tooth portion 32 of the lower comb tooth portion 31, the maximum value of the width of the teeth portion 23a of the upper comb tooth portion 22, that is, wider than the width W _UM of the root portion 25 of the teeth 23a Is desirable.

  In the present embodiment, since the distal end portion 26 of the tooth portion 23a is thinner than the root portion 25, even when the load is small, the distal end portion 26 of the tooth portion 23a of the upper comb tooth portion 22 is easily deformed, and the lower comb tooth portion 31. Easy to touch. For this reason, a minute load can be detected, and a detection range in which the load can be detected can be widened.

(Third embodiment)
FIG. 8 is a longitudinal sectional view showing the configuration of the upper electrode 11b of the pressure-sensitive sensor 100 according to the third embodiment of the present invention. The upper electrode 11b shown in FIG. 8 is different from the upper electrode 11 shown in FIG. 3 in that a tooth portion 23b is provided instead of the tooth portion 23 in the upper comb tooth portion 22. In addition, the other structure of the pressure-sensitive sensor 100 of this embodiment is the same as that of 1st Embodiment.

  The tooth portion 23 in the first embodiment shown in FIG. 3 has a linear shape when viewed from the side surface, but the tooth portion 23b shown in FIG. 8 swells toward the lower electrode 12 side when viewed from the side surface. A curved shape (more specifically, an R shape).

  In the present embodiment, since the tooth portion 23b is curved so as to swell toward the lower electrode 12, even if the load is small, the tip portion of the tooth portion 23b is easily deformed and easily contacts the lower comb tooth portion 31. For this reason, a minute load can be detected, and a detection range in which the load can be detected can be widened.

(Fourth embodiment)
In the present embodiment, the configuration of each unit will be described in more detail.

  In the first to third embodiments, as shown in FIG. 6, the upper substrate 1 has flexibility and is deformed when a load is applied, whereby the applied load is applied. Is transmitted to the upper electrode 11. At this time, as a matter of course, the upper substrate 1 needs to have a strength that does not contact the upper comb-teeth portion 22 of the upper electrode 11 when a load is applied. Further, the spacer 3 is not particularly limited as described above, but it is desirable to have flexibility and elasticity. The upper substrate 1 may be configured with a member that does not have flexibility. In this case, naturally, the spacer 3 needs to have flexibility and elasticity in order to transmit the load applied to the upper substrate 1 to the upper electrode 11.

  The upper substrate 1 and the upper electrode 11 may not be bonded to each other or may be bonded to each other. When the upper substrate 1 and the upper electrode 11 are not joined to each other, the configuration of the pressure-sensitive sensor 100 can be simplified. On the other hand, when the upper substrate 1 and the upper electrode 11 are bonded to each other, it is possible to suppress the positional deviation between the upper substrate 1 and the upper electrode 11. Therefore, even if a load is repeatedly applied to the pressure sensor 100, it is possible to suppress the position of the upper substrate 1 and the upper electrode 11 from being shifted and affecting the characteristics of the pressure sensor 100. .

  When the upper substrate 1 and the upper electrode 11 are bonded to each other, the bonding method is not particularly limited. For example, the upper substrate 1 and the upper electrode 11 are bonded to each other using an adhesive, an adhesive such as a thermosetting adhesive, or the like. In the case of using an adhesive, it is possible to easily join the upper substrate 1 and the upper electrode 11 by using a double-sided tape or the like, so that the pressure sensitive sensor 100 can be easily manufactured. In addition, when an adhesive is used, since the adhesive generally does not generate hysteresis as compared with the pressure-sensitive adhesive, it is possible to suppress a difference in detection value between when the load is applied and when the load is unloaded. . Further, the upper substrate 1 and the upper electrode 11 may be joined via an elastic film having flexibility such as a PET (polyethylene terephthalate) film.

  The material and material of the lower substrate 2 are appropriately selected according to the place where the pressure sensor 100 is installed.

  The load detection range in the pressure sensor 100 changes according to the thickness of the upper electrode 11. Specifically, the detection accuracy can be increased as the upper electrode 11 becomes thinner. For this reason, it is desirable to determine the thickness of the upper electrode 11 according to a desired detection range. In contrast, as the thickness of the upper electrode 11 increases, the occurrence of drift can be suppressed.

  Further, as the bending angle of the tooth portion 23 of the upper comb tooth portion 22 in the upper electrode 11 is increased, the processing of the upper electrode 11 is facilitated, and further, the detection range can be widened. On the contrary, the pressure sensor 100 can be made thinner as the bending angle of the tooth portion 23 is smaller.

(Fifth embodiment)
FIG. 9 is a longitudinal sectional view showing the structure of the pressure-sensitive sensor 100 according to the fifth embodiment of the present invention. FIG. 10 is an exploded perspective view showing the structure of the pressure-sensitive sensor 100 according to the fifth embodiment of the present invention. FIG.

  The pressure-sensitive sensor 100 of this embodiment shown in FIGS. 9 and 10 differs from the pressure-sensitive sensor 100 of the first embodiment described in FIGS. 1 to 6 in that it further includes a pressing member 4. In the pressure sensor 100 of the present embodiment, the upper substrate 1 and the upper electrode 11 are bonded to each other with the adhesive layer 5. The pressure-sensitive adhesive layer 5 is a layer formed of a pressure-sensitive adhesive, and can be formed by using, for example, a double-sided tape. In FIG. 10, the structure of the upper part of the pressure sensor 100, specifically, the upper board | substrate 1, the press member 4, the adhesive layer 5, and the upper electrode 11 is shown.

  In the first embodiment, the spacer 3 is provided between the upper substrate 1 and the lower substrate 2. However, in this embodiment, the spacer 3 is provided between the pressing member 4 and the lower substrate 2. The lower substrate 2 is supported at an interval. The upper substrate 1 is provided on the lower surface of the pressing member 4 (the surface facing the lower substrate 2). The pressing member 4 and the upper substrate 1 may not be joined to each other or may be joined to each other. The joining method at the time of joining is not particularly limited.

  On the upper surface of the pressing member 4 (surface opposite to the surface facing the lower substrate 2), a convex portion 4a that functions as a push button for applying a load to the pressure sensor 100 is provided. It is desirable that the convex portion 4 a is provided at the central portion of the pressing member 4. The pressing member 4 may be formed in a flat plate shape without the convex portion 4a. Moreover, in this embodiment, the upper board | substrate 1 is not provided with the convex part 1a shown in FIG.

  The pressure-sensitive adhesive layer 5 is a first pressure-sensitive adhesive layer that joins the upper substrate 1 and the upper electrode 11. Specifically, the pressure-sensitive adhesive layer 5 is provided on at least a part of the frame portion 21 of the upper electrode 11, and joins the upper substrate 1 and the frame portion 21 of the upper electrode 11.

  The pressing member 4 has flexibility, and transmits the load applied to the upper substrate 1 to the upper electrode 11 by being deformed. For this reason, in the present embodiment, even when the upper substrate 1 is formed of a member having no flexibility, the spacer 3 transmits the load applied to the upper substrate 1 to the upper electrode 11. There is no need to have flexibility and elasticity.

  As described above, according to the present embodiment, the flexible pressing member 4 having the upper substrate 1 on the lower surface and the lower substrate 2 are opposed to each other with the spacer 3 spaced apart. Therefore, the upper substrate 1 is not provided with flexibility, and the spacer 3 is not required to have flexibility and elasticity. Therefore, the pressure can be easily applied without adjusting the characteristics of the upper substrate 1 and the spacer 3 precisely. It becomes possible to detect.

  Further, in the present embodiment, the upper substrate 1 and the upper electrode 11 are joined via the adhesive layer 5 provided along the frame portion 21 of the upper electrode 11. For this reason, since it becomes possible to join the upper substrate 1 and the upper electrode 11 with a simple configuration, the configuration of the pressure-sensitive sensor 100 can be simplified.

(Sixth embodiment)
FIG. 11 is a longitudinal sectional view showing the structure of the pressure-sensitive sensor 100 according to the sixth embodiment of the present invention. FIG. 12 is an exploded perspective view showing the structure of the pressure-sensitive sensor 100 according to the sixth embodiment of the present invention. FIG.

  The pressure-sensitive sensor 100 shown in FIGS. 11 and 12 is different from the pressure-sensitive sensor 100 of the fifth embodiment shown in FIGS. 9 and 10 in the bonding method for bonding the upper substrate 1 and the upper electrode 11. Different. In the present embodiment, the upper substrate 1 and the upper electrode 11 are bonded to each other via a PET film 6 that is an elastic film. Specifically, the upper substrate 1 and the PET film 6 are bonded to each other via the pressure-sensitive adhesive layer 7, and the PET film 6 and the upper electrode 11 are bonded to each other via the pressure-sensitive adhesive layer 8. In FIG. 12, the configuration of the upper portion of the pressure sensor 100, specifically, the upper substrate 1, the pressing member 4, the PET film 6, the pressure-sensitive adhesive layers 7 and 8, and the upper electrode 11 are shown.

  The PET film 6 is an elastic film having flexibility. The PET film 6 has substantially the same shape as the upper substrate 1.

  The pressure-sensitive adhesive layer 7 is a second pressure-sensitive adhesive layer that joins the upper substrate 1 and the PET film 6. The pressure-sensitive adhesive layer 7 is provided along the X direction, which is the first direction, at a substantially central portion in the Y direction, which is the second direction, in the upper substrate 1 and the PET film 6.

  The pressure-sensitive adhesive layer 8 is a third pressure-sensitive adhesive layer that joins the PET film 6 and the upper electrode 11. The pressure-sensitive adhesive layer 8 is provided along the X direction at each of both ends of the PET film 6 and the upper electrode 11 in the Y direction. Accordingly, the pressure-sensitive adhesive layer 8 is provided along a portion extending in the X direction in the frame portion 21 of the upper electrode 11 and joins the frame portion 21 of the upper electrode 11 and the PET film 6 to each other.

  FIG. 13 is a diagram for explaining the operation of the pressure-sensitive sensor 100 in the present embodiment. FIG. 13 shows a perspective side view of the pressure-sensitive sensor 100 in an unloaded state where no load is applied and the pressure-sensitive sensor 100 in a loaded state where a load is applied.

  When no load is applied to the pressure-sensitive sensor 100, in this embodiment, as shown in FIG. 13A, the upper comb teeth 22 of the upper electrode 11 and the lower comb of the lower electrode 12 are used. The tooth portions 31 are formed so as not to contact each other.

  When the load F is applied to the convex portion 4a of the pressing member 4 of the pressure sensor 100, the load F is applied to the pressing member 4, the upper substrate 1, the adhesive layer 7, the PET film 6, and the adhesive layer 8. Via the upper electrode 11. And the upper electrode 11 bends according to the load F1, and the upper comb-tooth part 22 of the upper electrode 11 falls in connection with it, and as shown in FIG.13 (b), it contacts with the lower comb-tooth part 31 of the lower electrode 12. FIG. .

  At this time, since the upper substrate 1 and the upper electrode 11 are bonded via the PET film 6, it is possible to suppress the adhesive layer 8 from being deformed following the deformation of the upper electrode 11. Therefore, it is possible to suppress the occurrence of hysteresis due to the adhesive layer 8 being greatly deformed at both ends.

  As described above, according to this embodiment, the pressure-sensitive adhesive layer 7 that joins the upper substrate 1 and the PET film 6 is provided along the X direction at the substantially central portion of the upper substrate 1 in the Y direction. 6 and the upper electrode 11 are provided with adhesive layers 8 along the X direction at both ends of the upper electrode 11 in the Y direction. For this reason, since it becomes possible to suppress that the adhesive layers 7 and 8 deform | transform along the bending of the upper electrode 11, it becomes possible to suppress that a hysteresis generate | occur | produces in the adhesive layers 7 and 8. Become. As a result, it is possible to suppress a difference in the detection value of the pressure sensor 100 between when the load is loaded and when the load is unloaded.

Example 1
As Example 1, a pressure-sensitive sensor 100 having the configuration of the first embodiment was produced as follows.

  As the material of the upper electrode 11, a stainless steel (SUS304-CSP) plate having a thickness of 0.3 mm is prepared, and the stainless steel plate is punched to form the upper comb tooth portion 22 having four tooth portions 23 and a frame portion. 21 is formed integrally. Then, the upper electrode 11 is manufactured by bending the root portion 25 of the tooth portion 23 toward the lower electrode 12 by about 3 °.

  Also, a PET (PolyEthylene Terephthalate) sheet having a thickness of 250 μm is prepared as the lower substrate 2, and the line resistivity is 1 kΩ / mm at a position facing each tooth portion 23 of the upper electrode 11 of the lower substrate 2. A carbon paste is applied in a comb shape to form the lower electrode 12 (a pair of lower comb portions 31). At this time, the length of the lower electrode 12 (carbon paste) is made shorter than the length of the tooth portion 23 of the upper electrode 11 and the width is made wider than the width of the tooth portion 23 of the upper electrode 11. Then, the conductive wire 33 is formed with a conductive silver paste so that one side of each tooth portion 32 of the pair of lower comb tooth portions 31 is electrically connected.

  Further, the upper electrode 11 is attached to the upper substrate 1, and the upper substrate 1 and the lower substrate 2 are connected to each other with a space 3 therebetween with a gap therebetween.

(Example 2)
As a material for the upper electrode 11, an aluminum (A1050) plate having a thickness of 0.3 mm is prepared. Other points are the same as in the first embodiment.

Example 3
As a material for the upper electrode 11, a plate of carbon tool steel (SK85-CSP) having a thickness of 0.3 mm is prepared. Other points are the same as in the first embodiment.

(Example 4)
A carbon paste having a linear resistivity of 0.5 kΩ / mm is applied to the lower substrate 2 in a comb shape to form the lower electrode 12. Other points are the same as in the first embodiment.

(Example 5)
A carbon paste having a linear resistivity of 10 kΩ / mm is applied to the lower substrate 2 in a comb-like shape to form the lower electrode 12. Other points are the same as in the first embodiment.

(Example 6)
As a material for the upper electrode 11, an aluminum (A1050) plate having a thickness of 0.1 mm is prepared. Other points are the same as in the first embodiment.

(Example 7)
The same stainless steel plate as that of Example 1 prepared as the material of the upper electrode 11 is punched out, and the upper comb tooth portion 22 and the frame portion 21 having two tooth portions 23 are integrally formed. Other points are the same as in the first embodiment.

(Example 8)
The same stainless steel plate as that of Example 1 prepared as a material for the upper electrode 11 is punched out, and the upper comb tooth portion 22 and the frame portion 21 having three tooth portions 23 are integrally formed. Other points are the same as in the first embodiment.

Example 9
The same stainless steel plate as that of Example 1 prepared as the material for the upper electrode 11 is punched out, and the upper comb tooth portion 22 and the frame portion 21 having five tooth portions 23 are integrally formed. Other points are the same as in the first embodiment.

(Example 10)
The width of the carbon paste (tooth portion 32 of the lower comb tooth portion 31) applied to the lower substrate 2 is made narrower than the width of the tooth portion 23 of the upper electrode 11, contrary to the first embodiment. Other points are the same as in the first embodiment.

(Example 11)
The same stainless steel plate as that of Example 1 is prepared as a material for the upper electrode 11a, and the stainless steel plate is punched out so that four teeth having a substantially triangular shape whose width gradually decreases from the root portion 25 toward the tip portion 26. The upper comb-tooth portion 22 having the portion 23a and the frame portion 21 are integrally formed. Other points are the same as in the first embodiment. Note that the pressure-sensitive sensor 100 of Example 11 corresponds to the pressure-sensitive sensor 100 of the second embodiment.

(Example 12)
After the upper comb tooth portion 22 and the frame portion 21 are formed integrally as in the first embodiment, an R-shaped tooth portion 23b that is curved so as to swell toward the lower electrode 12 is formed. Other points are the same as in the first embodiment. The pressure sensor of Example 12 corresponds to the pressure sensor 100 of the third embodiment.

(Example 13)
As the material of the upper electrode 11, a PBT resin plate coated with a conductive material having a thickness of 0.3 mm is prepared. Other points are the same as in the first embodiment.

(Example 14)
A carbon paste having a linear resistivity of 13 kΩ / mm is applied to the lower substrate 2 in a comb shape to form the lower electrode 12. Other points are the same as in the first embodiment.

(Example 15)
As a material for the upper electrode 11, an aluminum (A1050) plate having a thickness of 0.05 mm is prepared. Other points are the same as in the first embodiment.

(Example 16)
As a material for the upper electrode 11, a plate of carbon tool steel (SK85-CSP) having a thickness of 1.0 mm is prepared. Other points are the same as in the first embodiment.

  In addition, in the pressure-sensitive sensor 100 produced in Examples 1-16, the tensile strength of the upper comb-tooth part 22 is 500 MPa in Examples 1, 4, 5, 7-12, and 14, Examples 2, 6, In the case of 15, 70 MPa, in Examples 3 and 16, 800 MPa, and in Example 13, 50 MPa.

(Comparative example)
As a comparative example, a conventional pressure sensor in which a pressure sensitive resistor made of resin is provided between electrodes is used. Here, the pressure sensor described in JP-A-2014-20954 is used as the conventional pressure sensor.

  Drift, noise, linearity, detection area, and power consumption were evaluated for the pressure sensitive sensors of Examples 1 to 16 and the comparative example, and the evaluation results are shown in Tables 1 and 2.

  In the evaluation of the drift, a load of 8N is applied to the pressure sensor, and the ratio “|” of the difference between the resistance value Re and the initial value Ri after 30 minutes with respect to the initial value Ri of the resistance value detected by the pressure sensor “| 1− (Re ÷ Ri) × 100 | [%] ”was measured as a drift value. In Tables 1 and 2, ◎ indicates that the drift value is less than 1%, ○ indicates that the drift value is less than 3%, Δ indicates that the drift value is less than 5%, and X indicates that the drift value is 5% or more.

  In the noise evaluation, a load of 8 N and a voltage of 5 V are applied to the pressure sensor, and a resistance value Rx (x = 0.1, 0.2,..., 60) is measured every 0.1 seconds. Then, the maximum value “Max {| 1− (Rx ÷ Rav) × 100 |} [%]” of the amplitude (ratio) of the difference between the resistance value Rx and the average value Rav with respect to the average value Rav for one minute of the resistance value Rx. Was measured as a noise value. In Tables 1 and 2, ◎ indicates a noise value of less than 1%, ◯ indicates a noise value of less than 3%, and Δ indicates a noise value of less than 5%.

  In the evaluation of linearity, a resistance value Ry (y = 1, 2,..., 8) when a load is increased from 1 N to 8 N with respect to the pressure sensor is measured, and the resistance value Ry is on an ideal straight line. The maximum value “Max {| 1- (Ry ÷ Rid) × 100 |} [%]” of the difference width between each resistance value Ry and the resistance value Rid on the ideal straight line with respect to the resistance value Rid was measured as a linear value. . The ideal straight line is an approximate straight line calculated from the resistance value Ry (y = 1, 2,..., 8) using the least square method. In Tables 1 and 2, ◎ indicates a linear value of less than 1.5%, ◯ indicates a linear value of less than 3%, and x indicates a linear value of 3% or more.

  In the evaluation of the detection area, the ratio of the load corresponding to the minimum resistance value when the load was increased with respect to the pressure sensor and the load corresponding to the maximum resistance value was measured as the detection area value. In Tables 1 and 2, ◎ indicates that the detection range value is 5 times or more.

  In the evaluation of power consumption, power consumption was measured when a load with a maximum detection range and a voltage of 5 V were applied to the pressure sensor. In Tables 1 and 2, ◎ indicates that power consumption is less than 10 mW, and ◯ indicates that power consumption is less than 25 mW.

  As shown in Tables 1 and 2, in all examples, the performance is improved as compared with the comparative example.

  In each embodiment and each example described above, the illustrated configuration is merely an example, and the present invention is not limited to the configuration.

For example, the upper substrate 1 and the lower substrate 2 do not need to use the spacer 3 as long as they can face each other with a space therebetween. FIG. 14 is a longitudinal sectional view showing an example of a pressure sensitive sensor 100 that does not use the spacer 3. In the example of FIG. 14, a pressure sensor 100 is a hollow casing 9, the upper substrate 1 provided on the upper surface of the inner casing 9, by using the lower surface of the case 9 as a lower substrate 2, the upper substrate 1 and lower The substrates 2 are opposed to each other at an interval. In this case, it is desirable to expose at least a part of the upper surface of the upper substrate 1 from the case 9 by providing an opening 9 a on the upper surface of the case 9 as shown in the example of the figure. Further, the upper substrate 1 has flexibility and transmits a load applied by deformation to the upper electrode 11. The upper substrate 1 needs to have a strength that does not contact the upper comb teeth portion 22 of the upper electrode 11 when a load is applied.

1 upper substrate 2 lower substrate 2a first portion 2b second portion 3 spaces Sa <br/> 4 pressing member 5,7,8 adhesive layer 6 PET film
9 Case 11, 11a, 11b Upper electrode 12 Lower electrode 21 Frame portion 22 Upper comb tooth portion 23, 23a, 23b Tooth portion 24 Recessed portion 25 Root portion 26 Tip portion 31 Lower comb tooth portion 32 Tooth portion 33 Conductive wire 33a Connection terminal 100 Pressure sensor

Claims (14)

A pressure sensor having an upper electrode and a lower electrode facing the upper electrode with a gap therebetween,
The upper electrode includes an upper comb tooth portion that is a pair of comb-tooth shaped members facing each other, and a frame portion that connects one end of each tooth portion of the upper comb tooth portion, and the upper comb tooth The part is bent to the lower electrode side,
The said lower electrode is a pressure-sensitive sensor which has a lower comb-tooth part which is a pair of comb-tooth shaped members provided in the position facing the said upper comb-tooth part, and is formed with a semiconductive resistor.   The pressure-sensitive sensor according to claim 1, wherein the pair of upper comb teeth are inserted into each other.   The pressure sensor according to claim 1 or 2, wherein the pair of upper comb teeth and the frame are integrally formed.   The pressure-sensitive sensor according to any one of claims 1 to 3, wherein a width of each tooth portion of the lower comb tooth portion is wider than a width of each tooth portion of the upper comb tooth portion.   The pressure-sensitive sensor according to any one of claims 1 to 4, wherein the number of teeth of the pair of upper comb teeth is 3 or more as a whole.   The pressure sensor according to any one of claims 1 to 5, wherein the upper comb portion is bent at an angle of 0.1 ° to 10 ° at a base portion.   The pressure-sensitive sensor according to any one of claims 1 to 6, wherein the upper comb-tooth portion has a tensile strength of 70 MPa or more.   The pressure-sensitive sensor according to any one of claims 1 to 7, wherein a thickness of each tooth portion of the upper comb tooth portion is 0.1 mm to 1 mm. 9. The pressure-sensitive sensor according to claim 1, wherein a resistance value per unit length of the lower comb-tooth portion is 10 Ω / mm to 10 ⁴ Ω / mm.   The pressure sensor according to any one of claims 1 to 9, wherein the upper comb portion is curved so as to swell toward the lower electrode.   The pressure sensor according to any one of claims 1 to 10, wherein each tooth portion of the upper comb tooth portion has a tip portion thinner than a root portion. An upper substrate having the upper electrode on the lower surface;
A lower substrate having the lower electrode on its upper surface;
A flexible pressing member comprising the upper substrate on the lower surface;
The pressure-sensitive sensor according to claim 1, further comprising a spacer that supports the lower substrate and the pressing member with a space therebetween. A first pressure-sensitive adhesive layer that joins the upper substrate and the upper electrode;
The pressure-sensitive sensor according to claim 12, wherein the first pressure-sensitive adhesive layer is provided along a frame portion of the upper electrode. An elastic film provided between the upper substrate and the upper electrode;
A second pressure-sensitive adhesive layer that joins the upper substrate and the elastic film;
A third pressure-sensitive adhesive layer that joins the elastic film and the upper electrode;
The second pressure-sensitive adhesive layer extends along the first direction at a substantially central portion in a second direction substantially orthogonal to the first direction in which the teeth of the upper comb teeth on the upper substrate are arranged. Provided,
The pressure-sensitive sensor according to claim 12, wherein the third pressure-sensitive adhesive layer is provided along each of the both ends of the upper electrode in the second direction along the first direction.

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