JPWO2014208294A1 - Capacitive sensor - Google Patents

Abstract

It is an object of the present invention to provide a capacitance type sensor that can suppress noise from the surroundings and that does not easily reduce detection accuracy. The capacitive sensor (1) includes a front side electrode part (FX), a back side electrode part (FY) disposed on the back side of the front side electrode part (FX), a front side electrode part (FX) and a back side electrode part (FY). And a dielectric layer (280) disposed between the sensor portion (F) and insulating spacers (250, 251) disposed on at least one of the front side and the back side of the sensor portion (F), The insulating spacers (250, 251) are arranged on the outer sides in the front and back direction, and are electrically connected to the grounding electrodes (240, 241) and the sensor unit (F) that are grounded, and apply a voltage to the sensor unit (F). And a control device (22F) to which an electric quantity related to the capacitance of the sensor unit (F) is transmitted.

Description

  The present invention relates to a capacitive sensor used as, for example, a load sensor or a touch sensor.

  For example, as shown in Patent Document 1, a capacitive sensor includes a plurality of front-side electrodes, a plurality of back-side electrodes, and a dielectric layer. The plurality of front electrodes are arranged on the front side of the dielectric layer. The plurality of backside electrodes are disposed on the backside of the dielectric layer. When viewed from the front side or the back side, the plurality of front-side electrodes and the plurality of back-side electrodes are orthogonal to each other. A plurality of detection units are set in a portion where the plurality of front-side electrodes and the plurality of back-side electrodes overlap. When a load is applied to the detection unit from the front side, the dielectric layer is compressed in the front and back direction. For this reason, the interelectrode distance between the front side electrode and back side electrode which comprises the said detection part becomes small. Therefore, the capacitance of the detection unit is increased.

  As described above, when the capacitance type sensor is used, the load applied to the detection unit can be detected based on the change in the capacitance due to the change in the distance between the electrodes. Further, the load distribution in the surface direction of the capacitive sensor can be detected by detecting the load in the plurality of detection units. For this reason, an electrostatic capacitance type sensor is used, for example in bedclothes, such as a bed and a futon, when measuring the body pressure distribution of the person who is sleeping.

JP 2012-173100 A

  However, when the capacitive sensor is arranged on the bedding, the detection accuracy of the capacitive sensor is lowered due to the influence of noise from peripheral devices (for example, an electric blanket). In this regard, noise can be suppressed by arranging a ground electrode in the capacitive sensor. However, if the ground electrode is arranged, current may escape from the detection unit of the capacitive sensor to the ground via the ground electrode. That is, the current from the detection unit that is originally used for measuring the capacitance may escape to the ground. For this reason, the detection accuracy of a capacitance type sensor will fall. SUMMARY OF THE INVENTION An object of the present invention is to provide a capacitance type sensor that can suppress noise from the surroundings and that does not easily reduce detection accuracy.

  (1) In order to solve the above problems, a capacitive sensor of the present invention includes a front side electrode part, a back side electrode part disposed on the back side of the front side electrode part, the front side electrode part, and the back side electrode part. A sensor part having a dielectric layer disposed between the insulating part, an insulating spacer disposed on at least one of the front side and the back side of the sensor part, and an earth that is disposed on the outer side in the front and back direction of the insulating spacer and is grounded An electrode and a control device that is electrically connected to the sensor unit, applies a voltage to the sensor unit, and transmits an electric quantity related to the capacitance of the sensor unit.

  The capacitive sensor of the present invention includes a ground electrode. For this reason, noise from peripheral devices can be suppressed. An insulating spacer is interposed between the ground electrode and the sensor unit. For this reason, the detection accuracy of the capacitive sensor is unlikely to decrease.

  (1-1) Preferably, in the configuration of (1), the front electrode portion includes a plurality of front electrodes arranged in parallel to each other, and the back electrode portion includes a plurality of back electrodes arranged in parallel to each other, When viewed from the front side or the back side, the plurality of front side electrodes and the plurality of back side electrodes extend in directions intersecting each other, and when viewed from the front side or the back side, the plurality of front side electrodes and the plurality of back side electrodes It is better to have a configuration in which a plurality of detection units are set in a portion where and overlap.

  According to this configuration, the load can be detected by the plurality of detection units. For this reason, the load distribution in the surface direction (direction orthogonal to the front and back directions) of the capacitive sensor can be detected.

  (2) Preferably, in the configuration of the above (1), the insulating spacer is preferably composed of a plurality of insulating films laminated in the front and back directions. According to this configuration, the thickness of the insulating spacer in the front and back direction (that is, the distance between the ground electrode and the sensor unit) can be easily adjusted by changing the number of laminated insulating films.

  (3) Preferably, in the configuration of the above (2), the insulating spacer includes a film connecting portion that partially connects the insulating films, and the insulating spacer includes a plurality of the insulating films formed by the film connecting portion. It is better to have a configuration including a constraining portion constrained to each other and a non-constraining portion in which the plurality of insulating films are not constrained to each other.

  The insulating spacer of the capacitive sensor having this configuration includes a restraining portion. For this reason, it can control that a plurality of insulating films shift mutually. In addition, the insulating spacer of the capacitive sensor of this configuration includes an unconstrained portion. For this reason, it can suppress that a deformation | transformation (for example, bending deformation) of a some insulating film restrains mutually. In addition, it is possible to allow the unconstrained portions of any one adjacent insulating film to slide with each other.

  Further, when the insulating film is bent and deformed, the amount of expansion of the outer surface in the radius direction of curvature relative to the inner surface in the radius direction of curvature is smaller as the thickness of the insulating film in the front and back direction is smaller. For example, when a load is applied to the insulating film from the front side, the extension amount of the back surface with respect to the surface of the insulating film may be smaller as the thickness of the insulating film in the front-back direction is smaller. Thus, the smaller the front and back direction thickness of the insulating film is, the easier it is for the insulating film to bend.

  In this regard, according to the present configuration, the insulating spacer is formed of a plurality of insulating films instead of a single insulating film. The insulating spacer includes a non-restraining portion. For this reason, compared with the insulating spacer consisting of a single insulating film (the thickness of the insulating film in the front and back direction is the sum of the thicknesses of the front and back sides of the plurality of insulating films), the plurality of insulating films of the insulating spacer of this configuration Each is easy to bend. Therefore, the insulating spacer of this configuration is easily bent.

  Thus, according to this configuration, the insulating spacer can be easily bent and deformed while sufficiently securing the thickness of the insulating spacer in the front and back direction (that is, the distance between the ground electrode and the sensor portion).

  (4) Preferably, in the configuration of the above (3), the film connecting portion includes a corner connecting portion disposed at a corner of the insulating spacer when viewed from the front side or the back side, and the angle viewed from the front side or the back side. It is better to have a configuration including a central coupling portion disposed inside the partial coupling portion. According to this structure, a constraining part can be locally set to an insulating spacer by a corner | angular part connection part and a center connection part.

  (5) Preferably, in the configuration of the above (4), the sensor unit is disposed on the back side of the surface of the bedding, and the central coupling unit is along the height direction of the sleeping person in the bedding, It is better to have an extended configuration.

  According to this configuration, when a person shifts from the lying position (sleeping state) to the sitting position (sitting state) or from the sitting position to the lying position, the plurality of insulating films are not easily displaced from each other. For this reason, it is difficult for people to feel uncomfortable.

  (6) Preferably, in the configuration of the above (3), the film connecting portion preferably has a plurality of strip-like connecting portions arranged in a stripe shape when viewed from the front side or the back side. According to this configuration, the band-shaped connecting portion can set the constraining portion in a striped manner on the insulating spacer.

  (7) Preferably, in the configuration of (6) above, the sensor unit is disposed on the back side of the surface of the bedding, and the band-shaped connecting unit is along the height direction of a sleeping person in the bedding, It is better to have an extended configuration.

  According to this configuration, when a person shifts from the lying position (sleeping state) to the sitting position (sitting state) or from the sitting position to the lying position, the plurality of insulating films are not easily displaced from each other. For this reason, it is difficult for people to feel uncomfortable.

  (8) Preferably, in any one of the constitutions (2) to (7), the insulating film is made of polyethylene. Polyethylene is inexpensive, has a low Young's modulus, and a low dielectric constant. For this reason, the insulating film of this structure has low manufacturing cost, is easy to bend, and has high insulation.

  (9) Preferably, in any one of the configurations (1) to (8), one of the front electrode portion and the back electrode portion is an input electrode portion to which the voltage is applied from the control device. And the other is an output side electrode part that transmits the amount of electricity to the control device, and the output side electrode part is arranged closer to the ground electrode than the input side electrode part. It is better to have a configuration.

  According to this structure, it can suppress that the noise from a peripheral device mixes in the electric quantity regarding the electrostatic capacitance of a sensor part. In addition, the earth electrode hardly affects the amount of electricity related to the capacitance of the sensor unit.

  (10) Preferably, in any one of the configurations (1) to (9), a positioning hole penetrating the sensor portion, the insulating spacer, and the ground electrode in the front and back direction, the sensor portion, the insulating spacer, And a bag-like cover that accommodates the ground electrode, and the front and back layers of the cover are preferably joined on the radially inner side of the positioning hole. According to this configuration, the sensor part, the insulating spacer, and the ground electrode inside the cover can be easily fixed and positioned with respect to the cover by joining both the front and back layers of the cover inside the positioning hole in the radial direction. .

  (10-1) Preferably, in the configuration of (10), the front and back layers of the cover are preferably welded. According to this configuration, both the front and back layers of the cover can be easily and firmly joined. Moreover, according to this structure, when joining a cover, another members, such as a clip, are unnecessary, for example. For this reason, when a person gets on the upper surface of the cover, riding comfort (for example, sitting comfort, sleeping comfort, etc.) is good.

  According to the present invention, it is possible to provide a capacitance type sensor that can suppress noise from the surroundings and that does not easily reduce detection accuracy.

FIG. 1 is a transparent top view of the capacitive sensor according to the first embodiment. 2 is a cross-sectional view in the II-II direction of FIG. FIG. 3 is an exploded perspective view of the capacitance type sensor. FIG. 4 is a block diagram of the capacitance type sensor. FIG. 5 is a transparent top view of the capacitive sensor according to the second embodiment. FIG. 6 is an exploded perspective view of the capacitance type sensor. FIG. 7 is an enlarged view in the frame VII of FIG. 8 is a cross-sectional view taken along the line VIII-VIII in FIG.

  Hereinafter, embodiments of the capacitive sensor of the present invention will be described. In the following drawings, the upper side corresponds to the “front side” of the present invention, and the lower side corresponds to the “back side” of the present invention. The front-rear direction corresponds to the “height direction of a sleeping person in the bedding” of the present invention.

<< First Embodiment >>
<Configuration of capacitive sensor>
First, the configuration of the capacitive sensor of this embodiment will be described. FIG. 1 shows a transparent top view of the capacitive sensor of the present embodiment. FIG. 2 shows a cross-sectional view in the II-II direction of FIG. FIG. 3 shows an exploded perspective view of the capacitance type sensor. FIG. 4 shows a block diagram of the capacitance type sensor.

  As shown in FIG. 1, the capacitive sensor 1 is laid under the bed sheet 9. The capacitance type sensor 1 is based on the fact that the distance between the electrodes of the detection unit CF (distance between the front electrode unit FX and the back electrode unit FY), which will be described later, changes according to the weight of the sleeping person M. The body pressure distribution of the upper body of the person M is measured. Note that another capacitive sensor (not shown) of the same type as the capacitive sensor 1 is disposed below the sheet 9. The capacitance type sensor measures the body pressure distribution of the lower body of the sleeping person M.

  As shown in FIGS. 1 to 4, the capacitive sensor 1 includes a sensor unit F, a connector 20 </ b> F, a harness 21 </ b> F, a control device 22 </ b> F, a cover 23, a front side ground electrode 240, and a back side ground electrode 241. The front-side insulating spacer 250, the back-side insulating spacer 251, the back-end base material 262, the four corner connecting portions 290, the three front central connecting portions 291, the three rear central connecting portions 292, and 4 Two overall connecting portions 293.

  The front side ground electrode 240 and the back side ground electrode 241 are each included in the concept of the “ground electrode” of the present invention. The front-side insulating spacer 250 and the back-side insulating spacer 251 are each included in the concept of “insulating spacer” of the present invention. The front center connecting portion 291 and the rear center connecting portion 292 are each included in the concept of “center connecting portion” of the present invention.

[Cover 23]
The cover 23 is made of a flexible soft urethane foam and has a bag shape. The cover 23 has an insulating property. Inside the cover 23, members other than the connector 20F, the harness 21F, and the control device 22F among the members constituting the capacitive sensor 1 are accommodated.

[Sensor part F]
The sensor part F includes a front side electrode part FX, nine front side wirings Fx, a back side electrode part FY, nine back side wirings Fy, a front side base material 260, a back side base material 261, and a front side cover coat 270. The rear cover coat 271, the dielectric layer 280, the reinforcing layer 281, and the detection unit CF are provided. The front side electrode portion FX corresponds to the “input side electrode portion” of the present invention. The back side electrode part FY corresponds to the “output side electrode part” of the present invention.

(Dielectric layer 280, reinforcing layer 281)
The dielectric layer 280 is made of a flexible flexible urethane foam (specifically, PORON (registered trademark of Roger Sinoac Co., Ltd.)) and has a rectangular film shape. The dielectric layer 280 has an insulating property.

  The reinforcing layer 281 is disposed below the dielectric layer 280. The reinforcing layer 281 is made of PET (polyethylene terephthalate) and has a quadrangular film shape. The reinforcing layer 281 is harder (having a higher Young's modulus) than the dielectric layer 280. The reinforcing layer 281 has an insulating property.

(Front side base material 260, front side electrode part FX, front side wiring Fx, front side cover coat 270)
The front substrate 260 is disposed on the upper side of the dielectric layer 280. The front-side base material 260 is made of PET and has a quadrangular film shape. The front side base material 260 has insulating properties.

  The nine front side wirings Fx are screen-printed on the lower surface of the front side base material 260. The front-side wiring Fx is made of silver paste and has conductivity. The front-side wiring Fx electrically connects a later-described front-side electrode FXa and a later-described connector 20F.

  The front side electrode portion FX includes nine front side electrodes FXa. The front side electrode FXa is linear, and is screen-printed on the lower surface of the front side base material 260. The front electrode FXa extends in the front-rear direction (Y direction). The nine front electrodes FXa are arranged in the left-right direction (X direction). The front electrode FXa is made of carbon paste and has conductivity. The front side electrode FXa partially covers the front side wiring Fx from the lower side. The front side wiring Fx is disposed over the entire length in the longitudinal direction of the front side electrode FXa.

  The front side cover coat 270 is made of polyester and has a quadrangular film shape. The front side cover coat 270 has an insulating property. The front side cover coat 270 is screen-printed on the lower surface of the front side base material 260. The front cover coat 270 covers nine front wirings Fx and nine front electrodes FXa from below.

(Back side base material 261, back side electrode part FY, back side wiring Fy, back side cover coat 271)
The back side substrate 261 is disposed below the reinforcing layer 281. The back side base material 261 is made of PET and has a quadrangular film shape. The back side base material 261 has an insulating property.

  The nine back side wirings Fy are screen-printed on the upper surface of the back side base material 261. The back side wiring Fy is made of silver paste and has conductivity. The back side wiring Fy electrically connects a back side electrode FYa described later and a connector 20F described later.

  The back-side electrode part FY includes nine back-side electrodes FYa. The back side electrode FYa is linear and is screen-printed on the upper surface of the back side base material 261. The back side electrode FYa extends in the left-right direction. The nine back electrodes FYa are arranged in the front-rear direction. The back electrode FYa is made of carbon paste and has conductivity. The back side electrode FYa partially covers the back side wiring Fy from above. The back side wiring Fy is disposed over the entire length in the longitudinal direction of the back side electrode FYa.

  The back side cover coat 271 is made of polyester and has a quadrangular film shape. The back side cover coat 271 has insulating properties. The back side cover coat 271 is screen-printed on the upper surface of the back side base material 261. The back side cover coat 271 covers nine back side wirings Fy and nine back side electrodes FYa from above.

(Detector CF)
When viewed from above, the nine front electrodes FXa and the nine back electrodes FYa are arranged in a lattice pattern. A detection unit CF is set in a portion where the front side electrode FXa and the back side electrode FYa overlap. A total of 81 detectors CF are arranged.

[Front-side insulating spacer 250, Front-side ground electrode 240]
The front side insulating spacer 250 is disposed on the upper side of the front side base material 260. The front-side insulating spacer 250 is made of PE (polyethylene) and has a rectangular film shape. The front insulating spacer 250 has an insulating property.

  On the upper surface (surface on the outer side in the front-back direction) of the front-side insulating spacer 250, front-side ground wiring (not shown) made of silver paste is screen-printed on the entire surface. The front-side ground electrode 240 is made of carbon paste and has a rectangular film shape. The front side ground electrode 240 has conductivity. The front side ground electrode 240 is entirely screen-printed on the upper surface of the front side ground wiring. The front side ground electrode 240 is electrically grounded via the front side ground wiring.

[Back-side insulating spacer 251, back-side ground electrode 241, back-end base material 262]
The back side insulating spacer 251 is disposed below the back side base material 261. As shown in FIG. 3, the back-side insulating spacer 251 includes five insulating films 251a. The insulating film 251a is made of PE and has a quadrangular film shape. The insulating film 251a has insulating properties.

  The back end base material 262 is disposed below the back side insulating spacer 251. The back end base material 262 is made of PET and has a quadrangular film shape. The back end base material 262 has an insulating property.

  On the upper surface of the back end base material 262, a back side ground wiring (not shown) made of silver paste is screen-printed on the entire surface. The back side ground electrode 241 is made of carbon paste and has a quadrangular film shape. The back side ground electrode 241 has conductivity. The back side ground electrode 241 is screen-printed on the entire upper surface of the back side ground wiring. The back-side ground electrode 241 is disposed below the back-side insulating spacer 251 (outside in the front-back direction). The back side ground electrode 241 is electrically grounded via the back side ground wiring.

[Corner connecting portion 290, front center connecting portion 291, rear center connecting portion 292, overall connecting portion 293]
As shown by hatching in FIG. 3, the four corner connecting portions 290 are disposed at the four corners of the back-side insulating spacer 251 when viewed from above. The corner connecting portion 290 extends in a direction orthogonal to the diagonal line of the back insulating spacer 251. The corner | angular part connection part 290 is formed by welding a pair of insulating films 251a adjacent to an up-down direction.

  As shown by hatching in FIG. 3, the three front center connecting portions 291 are arranged between a corner connecting portion 290 at the left front corner and a corner connecting portion 290 at the right front corner as viewed from above. . The front side central connecting portion 291 extends in the front-rear direction (the height direction of the person M shown in FIG. 1).

  As shown by hatching in FIG. 3, the three rear center coupling portions 292 are arranged between the corner coupling portion 290 at the left rear corner and the corner coupling portion 290 at the right rear corner when viewed from above. Has been. The rear center connecting portion 292 extends in the front-rear direction.

  As described above, the five insulating films 251a are not shifted from each other in the plane direction (horizontal direction) by the four corner connecting portions 290, the three front center connecting portions 291, and the three rear center connecting portions 292. Is integrated.

  The four whole connecting portions 293 are arranged at the four corners of the front-side ground electrode 240 when viewed from above. The overall connecting portion 293 is a resin-made binding tool having retaining portions at both upper and lower ends. The entire connecting portion 293 passes through the front side ground electrode 240, the front side insulating spacer 250, the sensor unit F, the back side insulating spacer 251, the back side ground electrode 241, and the back end base material 262 from the upper side to the lower side. As described above, these members are integrated by the four overall connecting portions 293 so as not to be displaced from each other in the surface direction.

  In the back side insulating spacer 251, a portion where the four corner connecting portions 290, the three front center connecting portions 291, the three rear center connecting portions 292, and the four whole connecting portions 293 are arranged is a restraining portion 251b. . In the restraining portion 251b, the five insulating films 251a are restrained to each other. For this reason, each insulation film 251a cannot shift | deviate to a surface direction with respect to the other insulation film 251a.

  On the other hand, in the back side insulating spacer 251, a portion where the four corner connecting portions 290, the three front central connecting portions 291, the three rear central connecting portions 292, and the four overall connecting portions 293 are not arranged is a non-constraining portion. 251c. In the unconstrained portion 251c, the five insulating films 251a are not restrained from each other. For this reason, each insulating film 251a can shift | deviate to a surface direction with respect to the other insulating film 251a.

[Connector 20F, harness 21F, control device 22F]
The connector 20F is disposed at the left front corner of the capacitive sensor 1. Nine front-side wirings Fx and nine back-side wirings Fy are electrically connected to the connector 20F in a state where insulation is ensured. The harness 21F electrically connects the connector 20F and a control device 22F described later.

  The control device 22F includes a power source 220, an input side switching circuit 221, an output side switching circuit 222, and a capacitance detecting unit 223. The power supply 220 applies an alternating voltage (specifically, a rectangular wave voltage) to the nine front electrodes FXa via the nine front wirings Fx.

  The input side switching circuit 221 includes nine switches (not shown). One end of the input side switching circuit 221 is connected to the power source 220. The other end of the input side switching circuit 221 is connected to nine front side wirings Fx. The input side switching circuit 221 switches and connects the nine front side wirings Fx to the power source 220 in order.

  The output side switching circuit 222 includes nine switches (not shown). One end of the output side switching circuit 222 is connected to nine back wirings Fy. The other end of the output side switching circuit 222 is connected to the capacitance detection unit 223. The output side switching circuit 222 switches and connects the nine back side wirings Fy to the capacitance detection unit 223 in order.

  The capacitance detection unit 223 includes the detection unit CF of the total of 81 detection units CF, which is related to the front side electrode FXa to which the voltage is applied and the back side electrode FYa connected to the capacitance detection unit 223. Measure the capacitance. Specifically, the capacitance detection unit 223 converts the charging current of the detection unit CF into capacitance. And the said electrostatic capacitance is measured. The charging current is included in the concept of “amount of electricity related to capacitance” of the present invention. A total of 81 detectors CF are sequentially applied with voltages in a scanning manner. For this reason, the body pressure distribution of the upper body of the sleeping person M can be measured.

[Effects of capacitive sensor]
Next, the function and effect of the capacitive sensor of this embodiment will be described. According to the capacitive sensor 1 of the present embodiment, the sensor unit F includes a total of 81 detection units CF in the surface direction. For this reason, the body pressure distribution of the upper body of the person M can be detected.

  In addition, the capacitive sensor 1 of this embodiment includes a front-side insulating spacer 250 and a front-side ground electrode 240. For this reason, the environmental noise resulting from the bedding (for example, electric blanket etc.) hung on the person M can be suppressed. Therefore, the detection accuracy can be increased.

  Further, the capacitive sensor 1 of this embodiment includes a back side insulating spacer 251 and a back side ground electrode 241. For this reason, the environmental noise resulting from the bedding and floor which the person M has spread can be suppressed. Therefore, the detection accuracy can be increased.

  In addition, when the inter-electrode distance between the back electrode FYa and the back side ground electrode 241 is less than a certain value with respect to the capacitance Ca of the detection unit CF, the current caused by the capacitance Ca causes the back side ground electrode 241 to flow. Escape to the ground. In this regard, the capacitive sensor 1 of this embodiment includes a back-side insulating spacer 251. For this reason, the electric current resulting from the electrostatic capacitance Ca can be sent to the electrostatic capacitance detection unit 223 of the control device 22F via the back side electrode FYa and the back side wiring Fy.

  Similarly, when the inter-electrode distance between the front side electrode FXa and the front side ground electrode 240 is less than a certain value with respect to the capacitance Ca of the detection unit CF, the current caused by the capacitance Ca is the front side ground. It escapes to the ground through the electrode 240. In this regard, the capacitive sensor 1 of this embodiment includes a front-side insulating spacer 250. For this reason, the electric current resulting from the electrostatic capacitance Ca can be sent to the electrostatic capacitance detection unit 223 of the control device 22F via the back side electrode FYa and the back side wiring Fy.

  Further, according to the capacitive sensor 1 of the present embodiment, the nine front wirings Fx, the nine front electrodes FXa, and the front cover coat 270 are screen-printed on the lower surface of the front substrate 260. For this reason, the shape accuracy and position accuracy of these members increase.

  Similarly, according to the capacitive sensor 1 of the present embodiment, the nine back wirings Fy, the nine back electrodes FYa, and the back cover coat 271 are screen-printed on the upper surface of the back substrate 261. For this reason, the shape accuracy and position accuracy of these members increase.

  Further, a front side laminate including the “front side base material 260, nine front side wirings Fx, nine front side electrodes FXa, front side cover coat 270” and the above “back side base material 261, nine back side wirings Fy, 9”. The configuration of the back side laminated body including the back side electrode FYa of the book and the back side cover coat 271 "is the same. That is, when the front side laminate is turned upside down and rotated appropriately in the horizontal plane, the back side laminate is obtained. Similarly, when the back side laminate is turned upside down and rotated appropriately in the horizontal plane, the front side laminate is obtained. For this reason, the laminated body of the same structure can be used as a front side laminated body and a back side laminated body.

  Further, according to the capacitive sensor 1 of the present embodiment, the reinforcing layer 281 is disposed below the dielectric layer 280. For this reason, the durability of the dielectric layer 280 is increased. Further, as compared with the case where the reinforcing layer 281 is disposed on the upper side of the dielectric layer 280, the dielectric layer 280 can be locally compressed only in a portion to which a load is applied. For this reason, the detection accuracy of the body pressure distribution can be increased.

  Further, according to the capacitive sensor 1 of the present embodiment, wiring (over the entire surface of the electrodes (front side electrode FXa, back side electrode FYa, front side ground electrode 240, back side ground electrode 241) as viewed from the front side or the back side) Front side wiring Fx, back side wiring Fy, front side ground wiring, back side ground wiring) are arranged. The wiring has a smaller electric resistance than the electrode. For this reason, it is possible to reduce the electrical resistance of the entire electrode by spreading the wiring over the entire electrode. In addition, variation in electrical resistance of the entire electrode can be reduced. In addition, it is possible to reduce variations in detection values between a plurality of detection units CF (for example, between the detection unit CF at the front end and the detection unit CF at the rear end). Therefore, the detection accuracy of the body pressure distribution can be increased.

  Further, according to the capacitive sensor 1 of the present embodiment, the back-side insulating spacer 251 is configured by five insulating films 251a stacked in the vertical direction. For this reason, by changing the number of laminated insulating films 251a, the thickness in the vertical direction of the back side insulating spacer 251 (that is, the distance between the back side ground electrode 241 and the back side electrode FYa) can be easily adjusted. .

  Moreover, as shown in FIG. 3, the back side insulating spacer 251 of the capacitive sensor 1 of the present embodiment includes a restraining portion 251b. For this reason, it can suppress that the five insulating films 251a shift | deviate mutually. Further, the back side insulating spacer 251 includes a non-restraining portion 251c. For this reason, it can suppress that the deformation | transformation (for example, bending deformation) of the five insulating films 251a is restrained mutually. Further, it is possible to allow the unconstrained portions 251c of any one adjacent insulating film 251a to slide with each other.

  In addition, when the insulating film 251a is bent and deformed, the amount of expansion of the outer surface in the radial direction of curvature relative to the inner surface in the radial direction of curvature may be smaller as the vertical thickness of the insulating film 251a is smaller. For example, when a load is applied to the insulating film 251a from above, the extension amount of the lower surface relative to the upper surface of the insulating film 251a may be smaller as the thickness of the insulating film 251a in the vertical direction is smaller. Thus, the insulating film 251a is more likely to bend as the thickness of the insulating film 251a is smaller.

  In this regard, according to the capacitive sensor 1 of the present embodiment, the back-side insulating spacer 251 is composed of five insulating films 251a instead of a single insulating film. Further, the back side insulating spacer 251 includes a non-restraining portion 251c. For this reason, compared with the back side insulating spacer which consists of a single insulating film (the vertical thickness of the said insulating film is the sum total of the vertical thickness of the five insulating films 251a), the back side insulating spacer of this embodiment Each of the five insulating films 251a 251 is easily bent. Therefore, the back side insulating spacer 251 of this embodiment is easy to bend. Therefore, the sleeping comfort is good.

  As described above, according to the capacitive sensor 1 of the present embodiment, the vertical thickness of the back insulating spacer 251 (that is, the distance between the back ground electrode 241 and the back electrode FYa) is sufficiently secured. The bending deformation of the back side insulating spacer 251 can be facilitated.

  Moreover, as shown in FIG. 3, the three front side center connection parts 291 and the three back side center connection parts 292 are extended along the height direction (front-back direction) of the sleeping person M. As shown in FIG. For this reason, when the person M shifts from the supine position (sleeping state) to the sitting position (sitting state) or from the sitting position to the supine position, the five insulating films 251a are not easily displaced from each other. Therefore, it is difficult for the person M to feel uncomfortable.

  The insulating film 251a is made of polyethylene. Polyethylene is inexpensive, has a low Young's modulus, and a low dielectric constant. For this reason, the insulating film 251a has a low manufacturing cost, is easily bent, and has a high insulating property.

<< Second Embodiment >>
The difference between the capacitive sensor of the present embodiment and the capacitive sensor of the first embodiment is that the entire connecting portion is formed by welding the front and back layers of the cover. In addition, the insulating spacer is formed by welding five insulating films in a striped pattern. Here, differences will be mainly described.

  FIG. 5 shows a transparent top view of the capacitive sensor of this embodiment. FIG. 6 shows an exploded perspective view of the capacitance type sensor. FIG. 7 shows an enlarged view in the frame VII of FIG. FIG. 8 is a sectional view taken along the line VIII-VIII in FIG.

  In FIG. 5, members corresponding to those in FIG. 1 are denoted by the same reference numerals. In FIG. 6, members corresponding to those in FIG. 8, members corresponding to those in FIG. 2 are denoted by the same reference numerals. In FIG. 5, the sheet 9 and the person M shown in FIG. 1 are omitted.

  As shown in FIGS. 5 to 7, four cover holes 230 are formed in the cover 23 of the capacitive sensor 1. As shown in FIG. 8, the cover hole 230 penetrates both the front and back layers of the cover 23 in the vertical direction (front and back direction).

  As shown in FIGS. 6 and 8, four positioning holes 8 are formed in the members (specifically, the sensor unit F, the back side ground electrode 241, and the back side insulating spacer 251) accommodated in the cover 23. ing. As shown in FIG. 8, the positioning hole 8 penetrates the member accommodated in the cover 23 in the vertical direction (front and back direction). The hole diameter (diameter) D1 of the positioning hole 8 is larger than the hole diameter (diameter) D2 of the cover hole 230. An entire connecting portion 293 is disposed on the radially inner side of the positioning hole 8 and on the radially outer side of the cover hole 230. The entire connecting portion 293 is formed by welding both the front and back layers of the cover 23. As shown by hatching in FIG. 7, when viewed from above, the overall connecting portion 293 has an annular shape centering on the cover hole 230. The overall connecting portion 293 positions the cover 23 and the member accommodated in the cover 23. Moreover, the whole connection part 293 positions the members accommodated in the cover 23 with respect to each other.

  As shown by hatching in FIG. 6, the plurality of strip-like connecting portions 294 are arranged in a stripe shape when viewed from above. The strip-shaped connecting portion 294 extends in the front-rear direction (the height direction of the person M shown in FIG. 1). The plurality of strip-like connecting portions 294 are arranged in parallel to each other. The strip-shaped connecting portion 294 is formed by welding a pair of insulating films 251a adjacent in the vertical direction. As described above, the five insulating films 251a are integrated by the plurality of strip-shaped connecting portions 294 so as not to be displaced from each other in the plane direction (horizontal direction).

  In the back-side insulating spacer 251, the portion where the belt-like connecting portion 294 is disposed is a restraining portion 251b. In the restraining portion 251b, the five insulating films 251a are restrained to each other. For this reason, each insulation film 251a cannot shift | deviate to a surface direction with respect to the other insulation film 251a.

  On the other hand, in the back side insulating spacer 251, the part where the belt-like connecting part 294 is not disposed is the non-restraining part 251c. In the unconstrained portion 251c, the five insulating films 251a are not restrained from each other. For this reason, each insulating film 251a can shift | deviate to a surface direction with respect to the other insulating film 251a.

  The back-side insulating spacer 251 is formed by first laminating 5 sheets of raw material having a size that allows the insulating film 251a to be cut out, and then laminating the 5 laminated webs in stripes, and finally 5 It is produced by cutting a sheet of raw material into a predetermined size. In this way, the back side insulating spacer 251 can be easily manufactured.

  The capacitive sensor of the present embodiment has the same effects as the capacitive sensor of the first embodiment with respect to the parts having the same configuration. Further, according to the capacitive sensor 1 of the present embodiment, as shown in FIG. 6, the band-shaped connecting portion 294 can set the constraining portion 251 b in the back-side insulating spacer 251 in a striped manner.

  Moreover, as shown in FIG. 6, the strip | belt-shaped connection part 294 is extended along the height direction of the person M of a sleeping state. For this reason, when the person M shifts from the supine position (sleeping state) to the sitting position (sitting state) or from the sitting position to the supine position, the plurality of insulating films 251a are not easily displaced from each other. For this reason, it is difficult for the person M to feel uncomfortable.

  Further, as shown in FIG. 8, both the front and back layers of the cover 23 are welded on the radially inner side of the positioning hole 8. For this reason, it is possible to easily fix and position the sensor portion F, the back side insulating spacer 251 and the back side ground electrode 241 inside the cover 23 with respect to the cover 23. Moreover, when joining the cover 23, another member, such as a clip, is unnecessary, for example. For this reason, when the person M rides on the upper surface of the cover 23, riding comfort (for example, sitting comfort, sleeping comfort, etc.) is good.

  Further, as shown in FIG. 8, both the front and back layers of the cover 23 are welded and sealed on the radially outer side of the cover hole 230. For this reason, foreign matter (solid, liquid, etc.) can be prevented from entering the cover 23.

  Further, the cover hole 230 penetrates the cover 23 in the vertical direction. For this reason, the cover hole 230 can ensure air permeability and moisture permeability in the up-down direction of the cover 23. Therefore, for example, when the cover 23 is laid, it is easy to vent the air below the cover 23. For this reason, it is easy to install the capacitive sensor 1. In addition, moisture tends to escape from the upper side to the lower side of the cover 23. For this reason, the person M on the capacitive sensor 1 is unlikely to become uncomfortable.

  Further, as shown in FIGS. 5 and 7, the cover hole 230, the positioning hole 8, and the entire connection portion 293 are arranged avoiding the front side electrode FXa and the back side electrode FYa. For this reason, the detection accuracy of the capacitive sensor 1 is unlikely to decrease.

<< Other >>
The embodiment of the capacitive sensor of the present invention has been described above. However, the embodiment is not particularly limited to the above embodiment. Various modifications and improvements that can be made by those skilled in the art are also possible.

  The configuration of the insulating film 251a is not particularly limited. An uneven shape may be imparted to at least one of the upper surface and the lower surface. Moreover, you may insert a slit in at least one among an upper surface and a lower surface. In addition, a textured sheet having an uneven shape may be used as the insulating film 251a.

  In the said embodiment, although the back side insulating spacer 251 was comprised with the some insulating film 251a, you may comprise the front side insulating spacer 250 with the some insulating film 251a.

  The number of the insulating spacers 250 and 251 is not particularly limited. The insulating spacers 250 and 251 may be arranged only on the front side or only on the back side of the sensor unit F. That is, the insulating spacers 250 and 251 may be disposed on at least one of the front and back sides of the sensor unit F. Similarly, the number of arrangement of the ground electrodes 240 and 241 is not particularly limited. The ground electrodes 240 and 241 may be disposed only on the front side or the back side of the sensor unit F. That is, the ground electrodes 240 and 241 may be disposed on at least one of the front and back sides of the sensor unit F.

  Further, the number of laminated insulating films 251a in the front-side insulating spacer 250 and the back-side insulating spacer 251 is not particularly limited. Single or multiple. In the case of a plurality, the thickness in the vertical direction of each insulating film 251a may or may not be constant.

  The structure of the corner | angular part connection part 290, the front side center connection part 291, the back side center connection part 292, and the whole connection part 293 is not specifically limited. Each member may be fixed by adhesion, a hook-and-loop fastener, an adhesive tape (for example, a double-sided tape), a stapler, a clip, or the like. The number, shape, and arrangement pattern of the film connecting portions are not particularly limited. For example, the film connecting portions may be arranged in a rectangular frame shape along the four sides of the insulating film 251a.

  Moreover, the joining method of the front and back both layers of the cover 23 shown in FIG. 8 is not specifically limited. For example, the front and back layers may be joined using an adhesive, a hook-and-loop fastener, an adhesive tape (for example, a double-sided tape), a stapler, a clip, or the like. Further, the cover hole 230 shown in FIG. Further, the position and the number of arrangement of the whole connecting portion 293 are not particularly limited.

  The number, shape, and arrangement pattern of the front side electrode FXa and the back side electrode FYa are not particularly limited. It is only necessary to set at least one detection unit CF. In the case where a plurality of detection units CF are arranged, the arrangement density of the detection units CF may not be constant over the entire detection area (area where the body pressure distribution can be detected). For example, the detection unit CF may be arranged densely in a portion where body pressure tends to concentrate and sparsely in a portion where body pressure is difficult to concentrate. Further, one of the front side electrode FXa and the back side electrode FYa may be arranged concentrically. In addition, the other may be arranged radially concentrically with one.

  In the above-described embodiment, nine front-side wirings Fx, nine front-side electrodes FXa, and a front-side cover coat 270 are screen-printed on the lower surface of the front-side base material 260. In addition, nine backside wirings Fy, nine backside electrodes FYa, and a backside cover coat 271 were screen-printed on the upper surface of the backside base material 261. However, each member may be printed by other printing methods such as an inkjet printing method, a flexographic printing method, a gravure printing method, a pad printing method, a lithography method, and a dispenser printing method. Moreover, you may arrange | position each said member by other arrangement | positioning methods, such as adhesion | attachment, sticking, and shaping | molding.

  Further, nine front-side wirings Fx, nine front-side electrodes FXa, and a front-side cover coat 270 may be printed on the upper surface of the dielectric layer 280. Similarly, nine backside wirings Fy, nine backside electrodes FYa, and a backside cover coat 271 may be printed on the lower surface of the dielectric layer 280. This increases the positional accuracy of the detection unit CF.

  Further, the front and back direction of the capacitive sensor of the present invention may not be the vertical direction. For example, the front and back direction may be the front-rear direction and the left-right direction (for example, when a capacitive sensor is arranged on a wall surface). The capacitive sensor of the present invention may be arranged on a curved surface as well as a flat surface. When arranged on a curved surface, the capacitive sensor bends along the shape of the curved surface.

  In the above embodiment, the front electrode portion FX is connected to the input side switching circuit 221 and the back side electrode portion FY is connected to the output side switching circuit 222. However, the connection destination of the front side electrode portion FX and the back side electrode portion FY is There is no particular limitation. For example, the front side electrode unit FX may be connected to the output side switching circuit 222, and the back side electrode unit FY may be connected to the input side switching circuit 221.

  Insulating member (for example, cover 23, front side insulating spacer 250, back side insulating spacer 251, front side base material 260, back side base material 261, back end base material 262, front side cover coat 270, back side cover coat 271 and dielectric layer 280 The material of the reinforcing layer 281 and the like is not particularly limited. What is necessary is just to have the softness | flexibility of the grade which curves with the weight of the person M. For example, a resin or an elastomer can be used. As the resin, PET, PE, PI (polyimide), PEN (polyethylene naphthalate), or the like can be used. Elastomers include silicone rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, epichlorohydrin rubber, chlorosulfonated polyethylene rubber, chlorinated polyethylene rubber, urethane rubber, ethylene propylene copolymer rubber, natural rubber, styrene-butadiene rubber. Etc. can be used. Further, as the material of the member having insulating properties, a resin or elastomer foam (for example, urethane foam, polyethylene foam, polystyrene foam, etc.) may be used. Further, a woven fabric or a nonwoven fabric of resin fibers (for example, polyester fibers, polyamide fibers, etc.) may be used as the material for the insulating member.

  The material of the conductive member (for example, the front side electrode FXa, the back side electrode FYa, the front side wiring Fx, the back side wiring Fy, the front side ground electrode 240, the back side ground electrode 241 and the like) is not particularly limited. What is necessary is just to have the softness | flexibility of the grade which curves with the weight of the person M. For example, an electrode material in which a conductive filler is contained in an elastomer as a base material may be used. In this case, the elastomer includes silicone rubber, ethylene-propylene copolymer rubber, natural rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, epichlorohydrin rubber, chlorosulfonated polyethylene, chlorinated polyethylene. Urethane rubber or the like can be used. Moreover, as an electroconductive filler, what consists of 1 or more types chosen from a carbon material and a metal can be used. As the metal, highly conductive silver, copper, or the like is preferable. For example, as the conductive filler, fine particles such as silver and copper, or fine particles having a surface plated with silver or the like can be used. Carbon materials have good conductivity and are relatively inexpensive. For this reason, when the conductive filler made of a carbon material is used, the manufacturing cost of the capacitive sensor 1 can be reduced. As the carbon material, for example, conductive carbon black, carbon nanotubes, carbon nanotube derivatives, graphite, conductive carbon fibers, and the like can be used. In particular, conductive carbon black, graphite, and conductive carbon fiber have good conductivity and are relatively inexpensive. For this reason, when these materials are used, the manufacturing cost of the capacitive sensor 1 can be reduced. Moreover, you may use the woven fabric of a conductive fiber, a nonwoven fabric, etc. as a material of the member which has electroconductivity.

  The capacitive sensor of the present invention may be embodied as a mutual capacitive touch sensor. In this case, one of the front-side electrode portion FX and the back-side electrode portion FY may be set as the reception electrode and the other as the transmission electrode.

1: Capacitive sensor.
20F: Connector, 21F: Harness, 22F: Control device, 23: Cover, 220: Power supply, 221: Input side switching circuit, 222: Output side switching circuit, 223: Capacitance detection unit, 230: Cover hole, 240: Front side ground electrode (ground electrode), 241: Back side ground electrode (ground electrode), 250: Front side insulating spacer (insulating spacer), 251: Back side insulating spacer (insulating spacer), 251a: Insulating film, 251b: Restraint portion, 251c: Unconstrained part, 260: Front side base material, 261: Back side base material, 262: Back end base material, 270: Front side cover coat, 271: Back side cover coat, 280: Dielectric layer, 281: Reinforcement layer, 290: Corner part connection 291: Front side central coupling part (central coupling part), 292: Rear side central coupling part (central coupling part), 293: Overall coupling part, 294: Band-shaped coupling part
8: Positioning hole.
9: Sheets.
CF: detection part, D1: hole diameter, D2: hole diameter, F: sensor part, FX: front side electrode part (input side electrode part), FXa: front side electrode, FY: back side electrode part (output side electrode part), FYa: back side Electrode, Fx: front side wiring, Fy: back side wiring, M: human.

Claims (10)

A sensor unit having a front side electrode unit, a back side electrode unit disposed on the back side of the front side electrode unit, and a dielectric layer disposed between the front side electrode unit and the back side electrode unit;
An insulating spacer disposed on at least one of the front side and the back side of the sensor unit;
An earth electrode disposed on the outer side in the front and back direction of the insulating spacer and grounded;
A controller that is electrically connected to the sensor unit, applies a voltage to the sensor unit, and transmits an electrical quantity related to the capacitance of the sensor unit;
A capacitive sensor comprising:   The capacitive sensor according to claim 1, wherein the insulating spacer includes a plurality of insulating films laminated in a front-back direction. A plurality of the insulating films are partially provided with a film connecting portion that connects each other,
The insulating spacer includes a restraining portion in which the plurality of insulating films are restrained from each other by the film connecting portion, and a non-constraining portion in which the plurality of the insulating films are not restrained from each other. The capacitance type sensor described.   The film connecting portion includes a corner connecting portion disposed at a corner portion of the insulating spacer as viewed from the front side or the back side, and a central connecting portion disposed inside the corner portion connecting portion as viewed from the front side or the back side, The electrostatic capacity type sensor according to claim 3 which has. The sensor part is disposed on the back side of the surface of the bedding,
The capacitive sensor according to claim 4, wherein the central connecting portion extends along a height direction of a sleeping person in the bedding.   The capacitive sensor according to claim 3, wherein the film connecting portion includes a plurality of strip-shaped connecting portions arranged in a stripe shape when viewed from the front side or the back side. The sensor part is disposed on the back side of the surface of the bedding,
The capacitive sensor according to claim 6, wherein the belt-shaped connecting portion extends along a height direction of a sleeping person in the bedding.   The capacitive sensor according to claim 2, wherein the insulating film is made of polyethylene. Of the front-side electrode part and the back-side electrode part, one is an input-side electrode part to which the voltage is applied from the control device, and the other is an output-side electrode part that transmits the amount of electricity to the control device,
The capacitive sensor according to any one of claims 1 to 8, wherein the output side electrode portion is disposed closer to the ground electrode than the input side electrode portion. A positioning hole penetrating the sensor part, the insulating spacer, and the ground electrode in the front and back direction; and
A bag-like cover for housing the sensor unit, the insulating spacer, and the ground electrode;
With
The capacitive sensor according to any one of claims 1 to 9, wherein the front and back layers of the cover are joined on the radially inner side of the positioning hole.

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