JP2014190712A - Gripping state detection sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gripping state detection sensor capable of detecting in details a gripping state of a driver of a part to be gripped.SOLUTION: A gripping state detection sensor 1 includes: a first base material 20 having insulation and made of elastomer; a plurality of first front surface side electrodes X1, X2 arranged on a front surface of the first base material 20 and having electroconductivity and made of elastomer; and a plurality of first rear surface side electrodes Y1 to Y8 arranged on a rear surface of the first base material 20 and having electroconductivity and made of elastomer. The gripping state detection sensor further includes: a proximity sensor part 2 for detecting an approach of a driver to a part 8 to be gripped and coordinates of the driver based on a change of an electrostatic capacitance Ca between the first front surface side electrodes X1, X2 and the first rear surface side electrodes Y1 to Y8; and a load sensor part 3 arranged on the rear surface of the proximity sensor part 2 and detecting a pressing of the driver to the part 8 to be gripped based on a load F applied from the driver via the proximity sensor part 2.

Description

  The present invention relates to a gripping state detection sensor that detects a gripping state of a driver with respect to a gripped portion such as a steering wheel (handle) of a vehicle.

  Patent Documents 1 and 2 disclose a load sensor disposed on a steering wheel. According to the load sensor described in Patent Document 1, the load can be detected based on the change in the impedance of the conductive rubber. According to the load sensor described in Patent Document 2, a load can be detected based on a change in capacitance.

  Patent Document 3 discloses a contact sensor disposed on a steering wheel. In paragraph [0020] of the document, examples of the contact sensor include an electrostatic sensor, an infrared reflection type distance sensor, a pressure sensor, and a temperature sensor.

Japanese Patent Laid-Open No. 5-34569 JP 2007-76491 A JP 2009-248629 A

  By the way, in recent years, from the viewpoint of improving the safety of a vehicle, there is an increasing need to detect in detail the gripping state of the driver with respect to the steering wheel. That is, when the driver grips the steering wheel, first, a hand is brought close to the steering wheel, then the steering wheel is touched by hand, and finally the steering wheel is gripped by hand. There is a growing need for detailed recognition of such gripping states of non-contact, contact, and gripping.

  However, all of the steering wheels disclosed in Patent Documents 1 to 3 are provided with a single type of sensor (load sensor or pressure sensor). For this reason, the driver's gripping state with respect to the steering wheel cannot be detected in detail.

  For example, even if only a load sensor is disposed on the steering wheel, it is difficult to detect the approach of the driver to the steering wheel. On the other hand, even if only the contact sensor is arranged on the steering wheel, it is difficult to detect the driver's grip on the steering wheel.

  Accordingly, an object of the present invention is to provide a gripping state detection sensor capable of detecting in detail a gripping state of a driver with respect to a gripped portion such as a steering wheel.

  (1) In order to solve the above problems, a gripping state detection sensor of the present invention is a gripping state detection sensor disposed on a gripped portion of a vehicle gripped and operated by a driver, and has an insulating property and an elastomer. A first base material made of metal, a plurality of first front electrode electrodes made of an elastomer having conductivity and disposed on the front side of the first base material, and a back surface of the first base material having conductivity. A plurality of first backside electrodes made of elastomer, and the capacitance is changed based on a change in capacitance between the first front side electrode and the first backside electrode as the driver approaches. The proximity sensor unit that detects the approach and coordinates of the driver with respect to the gripping unit, and the back side of the proximity sensor unit, and the load applied to the gripped unit based on the load applied by the driver via the proximity sensor unit And a load sensor unit that detects the driver's depression.

  Here, “approach” includes not only non-contact but also contact. In addition, in the case of “made of elastomer”, the object (first base material, first front side electrode, first back side electrode) is made of a simple substance of the elastomer, of course, the object is a substance other than elastomer (for example, the object In the case of imparting conductivity, the case of having a conductive filler) is also included. In addition, “pushing” includes gripping and pressing on the gripped portion.

  The gripping state detection sensor of the present invention includes a proximity sensor unit and a load sensor unit. The proximity sensor unit can detect the approach of the driver (for example, the driver's hand (palm, finger), etc.) to the gripped part based on the change in capacitance. Further, the proximity sensor unit can detect the coordinate in the surface direction of the driver based on the coordinate whose capacitance has changed. Moreover, the load sensor part can detect a driver | operator's pushing with respect to a to-be-gripped part. Thus, according to the gripping state detection sensor of the present invention, the approach, push-in, and coordinates of the driver with respect to the gripped portion can be detected. That is, the gripping state of the driver with respect to the gripped portion can be detected in detail.

  The proximity sensor unit includes a first front electrode, a first base material, and a first back electrode from the front side (load input side) to the back side (however, between adjacent layers). Other layers may be present). The first front side electrode, the first base material, and the first back side electrode are all made of an elastomer that is softer than the resin. For this reason, a proximity sensor part is flexible. Therefore, even if the gripping state detection sensor is disposed on the gripped portion, there is little risk of impairing the tactile sensation inherent to the gripped portion. In addition, the flexible proximity sensor unit hardly distributes the load applied by the driver in the surface direction. For this reason, the detection accuracy of the coordinate of a surface direction is high.

  In addition, the flexible proximity sensor part has high followability to the shape of the gripped part. For this reason, the gripping state detection sensor can be arranged along the shape of the gripped portion with respect to the gripped portion of any shape. Therefore, the versatility with respect to the shape of the gripped portion is high.

  In addition, the proximity sensor part of the grip state detection sensor of the present invention can be used alone without being combined with the load sensor part.

  (1-1) Preferably, in the configuration of the above (1), the proximity sensor unit increases a capacitance between the first front electrode and the first back electrode as the driver approaches. Based on this, it is better to adopt a configuration for detecting the approach and coordinates of the driver. According to this configuration, a self-capacitance type capacitive sensor can be used as the proximity sensor unit.

  (1-2) Preferably, in the configuration of (1) above, the first front side electrode, the first base material, and the first back side electrode elastomer (elastomer simple substance excluding inclusions such as conductive filler) are Young. It is better that the rate is 30 MPa or less. According to this configuration, the proximity sensor unit becomes flexible. For this reason, even if the gripping state detection sensor is arranged on the gripped portion, there is little risk of impairing the tactile sensation inherent in the gripped portion. Moreover, the detection accuracy of the surface direction coordinate is high. Moreover, the versatility with respect to the shape of a to-be-held part is high.

  (2) Preferably, in the configuration of the above (1), the proximity sensor unit generates a capacitance between the first front electrode and the driver as the driver approaches, and the first sensor Based on the decrease in the capacitance between the front side electrode and the first back side electrode, it is preferable to detect the approach and coordinates of the driver with respect to the gripped portion. According to this configuration, a mutual capacitance type capacitive sensor can be used as the proximity sensor unit. For this reason, it is easy to cope with multi-touch (multi-point simultaneous contact).

  (3) Preferably, in the configuration of the above (1) or (2), the load sensor portion is disposed on the front side of the second base material made of an elastomer having an insulating property and the second base material. A plurality of second front-side electrodes made of elastomer, and a plurality of second back-side electrodes made of elastomer that are disposed on the back side of the second base material and have conductivity. Based on the fact that the distance between the two front electrodes and the second back electrode is shortened and the capacitance between the second front electrode and the second back electrode is increased, the gripped portion It is better to adopt a configuration that detects the driver's push against the vehicle.

  According to the load sensor section of the gripping state detection sensor of this configuration, the push-in (specifically, whether there is push, the degree of push, the presence or absence of load, the degree of load, the value of load, etc.) ) Can be detected.

  Moreover, the load sensor part is provided with the 2nd front side electrode, the 2nd base material, and the 2nd back side electrode from the front side toward the back side (however, another layer intervenes between adjacent layers) You may). The second front side electrode, the second base material, and the second back side electrode are all made of an elastomer that is softer than the resin. For this reason, a load sensor part is flexible. Therefore, even if the gripping state detection sensor is disposed on the gripped portion, there is little risk of impairing the tactile sensation inherent to the gripped portion.

  In addition, the flexible load sensor unit has high followability to the shape of the gripped part. For this reason, the gripping state detection sensor can be arranged along the shape of the gripped portion with respect to the gripped portion of any shape. Therefore, the versatility with respect to the shape of the gripped portion is high.

  (3-1) Preferably, in the configuration of (3) above, the second front-side electrode, the second base material, and the second back-side electrode elastomer (elastomer alone excluding inclusions such as a conductive filler) are Young. It is better that the rate is 30 MPa or less. According to this structure, a load sensor part becomes flexible. For this reason, even if the gripping state detection sensor is arranged on the gripped portion, there is little risk of impairing the tactile sensation inherent in the gripped portion. Moreover, the versatility with respect to the shape of a to-be-held part is high.

  (4) Preferably, in the configuration of (3) above, it is better to have a configuration including an intermediate layer disposed between the proximity sensor portion and the load sensor portion and having conductivity. According to this configuration, the intermediate layer is interposed between the proximity sensor unit and the load sensor unit. The intermediate layer has conductivity. The intermediate layer is grounded. For this reason, a proximity sensor part and a load sensor part are hard to receive the bad influence of a mutual noise. Therefore, the detection accuracy of the proximity sensor unit and the load sensor unit is increased.

  (5) Preferably, in the configuration of the above (4), the intermediate layer is arranged on at least one of the front and back sides and has an insulating insulating spacer made of elastomer.

  According to this structure, the front-back direction distance (distance between electrodes) between the 1st back side electrode of a proximity sensor part and the 2nd front side electrode of a load sensor part can be lengthened. For this reason, it is possible to suppress the generation of stray capacitance between the first back side electrode and the second front side electrode. Therefore, mutual interference between the proximity sensor unit and the load sensor unit can be reduced, and the detection accuracy is increased.

  (5-1) Preferably, in the configuration of the above (5), the load sensor unit can detect the driver's coordinates with respect to the gripped portion, and the insulating spacer has the load dispersed in a surface direction. It is better to have a structure having a load dispersion suppression mechanism that suppresses this.

  In order to suppress the generation of stray capacitance between the first back-side electrode and the second front-side electrode, it is preferable that the thickness of the insulating spacer in the front-back direction is thicker. However, when the thickness of the insulating spacer is increased, the load applied by the driver is transmitted in the plane direction (specifically, the direction orthogonal to the front and back direction of the insulating spacer. The surface of the insulating spacer. Or it becomes easy to disperse | distribute to the direction where a back surface extends. For this reason, in the load sensor part on the back side of the insulating spacer, the detection accuracy of the coordinates in the surface direction is lowered.

  In this regard, the insulating spacer of this configuration includes a load dispersion suppressing mechanism. For this reason, when the load applied from the driver is transmitted through the insulating spacer, it is difficult for the load to be distributed in the surface direction. Therefore, the accuracy of detecting the coordinates in the surface direction is increased. Moreover, the load detection accuracy is increased.

  (5-2) Preferably, in the configuration of (5-1), the load sensor unit includes a plurality of the second front electrodes and a plurality of the second back electrodes as viewed from the front side or the back side. It is preferable that the load dispersion suppressing mechanism is interposed between the overlapping portions adjacent to each other in the surface direction when viewed from the front side or the back side.

  A case is assumed in which a load is input through an insulating spacer from the front side of an arbitrary overlapping portion among a plurality of overlapping portions (that is, load detecting portions) adjacent to each other in the surface direction. According to this configuration, the load dispersion suppression mechanism is interposed between an arbitrary overlapping portion and the overlapping portion adjacent to the overlapping portion. For this reason, in the insulating spacer, the load is difficult to disperse in the surface direction. Therefore, it is possible to suppress erroneous transmission of the input load to the adjacent overlapping portion.

  (5-3) Preferably, in the configuration of (5-1) or (5-2) above, the load distribution suppression mechanism is a load distribution suppression groove that is recessed in the front surface or the back surface of the insulating spacer. Is better.

  In the insulating spacer, the portion where the load dispersion suppressing groove is formed has a smaller thickness in the front and back direction than the portion where the load dispersion suppressing groove is not formed. For this reason, the spring constant in the surface direction becomes small. Therefore, it is possible to suppress the load from being dispersed in the surface direction.

  (5-4) Preferably, in the configuration of (5-1) or (5-2) above, the load distribution suppression mechanism is a load distribution suppression hole that penetrates the insulating spacer in the front-back direction. Is good.

  The portion of the insulating spacer where the load dispersion suppression hole is formed has a smaller spring constant in the surface direction than the portion where the load dispersion suppression hole is not formed. For this reason, it can suppress that a load disperse | distributes to a surface direction.

(6) Preferably, in any one of the configurations (3) to (5), the proximity sensor unit includes an elastomer first front insulating layer disposed on the front side of the plurality of first front electrodes, An elastomer-made first back-side insulating layer disposed on the back side of the plurality of first back-side electrodes, and the load sensor portion is a second elastomer-made material disposed on the front side of the plurality of second front-side electrodes. A front-side insulating layer and an elastomer-made second back-side insulating layer disposed on the back side of the plurality of second back-side electrodes, and satisfying at least one of the following (a) and (b): Better.
(A) In the proximity sensor unit, the first front electrode is printed on at least one of the first base material and the first front insulating layer, and the first back electrode is the first It is printed on at least one of the base material and the first backside insulating layer.
(B) In the load sensor unit, the second front electrode is printed on at least one of the second base material and the second front insulating layer, and the second back electrode is It is printed on at least one of the base material and the second back side insulating layer.

  According to this configuration, the first front electrode, the first back electrode, the second front electrode, and the second back electrode can be easily formed. Moreover, formation and arrangement | positioning of these electrodes can be performed simultaneously. Further, the degree of freedom in setting the shape of these electrodes is increased. Further, the accuracy of the shape of these electrodes is increased. In the case of (a), the relative alignment between the first front electrode and the first back electrode is facilitated. Similarly, in the case of (b), the relative alignment between the second front electrode and the second back electrode is facilitated.

  (7) Preferably, in any one of the configurations (1) to (6), the gripped portion is a steering wheel. According to this configuration, the gripping state of the driver with respect to the steering wheel can be detected in detail.

  According to the present invention, it is possible to provide a gripping state detection sensor that can detect in detail a gripping state of a driver with respect to a gripped portion such as a steering wheel.

1 is a front view of a steering wheel on which a gripping state detection sensor according to an embodiment of the present invention is disposed. It is the II-II direction sectional drawing of FIG. It is a Z direction permeation | transmission front view of the load sensor part of the sensor laminated body of the holding | grip state detection sensor. It is a Z direction exploded front view of the load sensor part. It is a Z direction transmission front view of the proximity sensor part of the sensor laminate. It is a Z direction exploded front view of the proximity sensor unit. FIG. 6 is an enlarged view of the vicinity of two overlapping portions at the left end in the X direction in FIG. 5. It is Z direction sectional drawing of the sensor laminated body. It is a block diagram of the grip state detection sensor. (A) is the enlarged view in the state where the hand is not approaching in the frame X of FIG. (B) is an enlarged view in the state where the hand is approaching in the frame X of FIG. (A) is the enlarged view in the state where the hand is not pushed in in the frame XI of FIG. (B) is an enlarged view in the state where the hand is pushed in the frame XI of FIG. It is a flowchart of the process which the control unit of the holding | grip state detection sensor performs. It is a Z direction front view of an insulating spacer of a grasping state detection sensor of other embodiments.

  Hereinafter, embodiments of the gripping state detection sensor of the present invention will be described.

[Configuration of gripping state detection sensor]
First, the configuration of the gripping state detection sensor of the present embodiment will be described. In the following drawings, the circumferential direction of the steering wheel is defined as the X direction, the circumferential direction of the radial cross section of the steering wheel is defined as the Y direction, and the radial direction of the radial cross section of the steering wheel is defined as the Z direction.

  FIG. 1 shows a front view of a steering wheel on which a gripping state detection sensor of the present embodiment is arranged. As shown in FIG. 1, three gripping state detection sensors 1 are arranged on a circular steering wheel 8. Each of the three gripping state detection sensors 1 extends in the X direction over 120 °.

  FIG. 2 shows a cross-sectional view in the II-II direction of FIG. As shown in FIG. 2, the gripping state detection sensor 1 includes a sensor stack 6 and a control unit (not shown). The sensor laminate 6 has a flexible sheet shape. The sensor laminate 6 is wound (one turn) around the core 80 of the steering wheel 8. Specifically, both ends of the sensor laminate 6 in the Y direction are in contact with each other at the radially inner end of the steering wheel 8. Further, the center of the sensor laminate 6 in the Y direction is disposed at the radially outer end of the steering wheel 8. The outer peripheral surface of the sensor laminate 6 is covered with a skin 81 of the steering wheel 8. It is the epidermis 81 that the driver directly touches.

{Sensor stack 6}
The sensor laminate 6 includes a proximity sensor unit 2, a load sensor unit 3, and an intermediate unit 4. The load sensor unit 3 covers the outer peripheral surface of the core unit 80. The proximity sensor unit 2 is disposed on the front side of the load sensor unit 3 in the Z direction (the side of the skin 81 shown in FIG. 2). The intermediate part 4 is arranged between the load sensor part 3 and the proximity sensor part 2.

(Load sensor 3)
FIG. 3 shows a Z direction transparent front view of the load sensor portion of the sensor stack of the gripping state detection sensor of the present embodiment. In FIG. 4, the Z direction exploded front view of the same load sensor part is shown. The white arrows in FIG. 4 indicate the stacking order. The hatched arrows in FIG. 4 indicate the printing order.

  As shown in FIGS. 3 and 4, the load sensor unit 3 includes a second front insulating layer 32 and eight second front sides from the Z direction front side toward the Z direction back side (core part 80 side shown in FIG. 2). Wirings a1 to a8, eight second front side electrodes y1 to y8, a second intermediate front side insulating layer 35, a second base material 30, a second intermediate back side insulating layer 36, and two second back side electrodes x1, It is formed by stacking x2, two second back-side wirings b1 and b2, and a second back-side insulating layer 33.

  The second base material 30 is made of urethane rubber and has a strip shape long in the X direction. The second base material 30 is flexible and has an insulating property.

  The second intermediate front side insulating layer 35 is made of acrylic rubber and has a strip shape that is long in the X direction. The second intermediate front side insulating layer 35 is flexible and has an insulating property. The second intermediate front side insulating layer 35 is laminated on the surface of the second base material 30.

  The eight second front electrodes y1 to y8 are each formed to include acrylic rubber and conductive carbon black. The eight second front-side electrodes y1 to y8 are each flexible and conductive. The eight second front side electrodes y <b> 1 to y <b> 8 are disposed on the front side of the second intermediate front side insulating layer 35. The eight second front-side electrodes y1 to y8 each have a barrel shape that is long in the Y direction. The eight second front electrodes y1 to y8 are arranged side by side in the X direction. The eight second front electrodes y <b> 1 to y <b> 8 are arranged symmetrically with respect to the Y-direction center line L <b> 2 of the load sensor unit 3. As shown in FIG. 2, the Y-direction center line L <b> 2 is disposed at the radially outer end of the steering wheel 8.

  The eight second front wirings a1 to a8 are each made of silver paste. The eight second front wirings a1 to a8 each have conductivity. The eight second front wirings a1 to a8 cover the surfaces of the wiring portions of the eight second front electrodes y1 to y8.

  The second front-side insulating layer 32 is made of urethane rubber and has a strip shape that is long in the X direction. The second front insulating layer 32 is flexible and has an insulating property. The second front insulating layer 32 is laminated on the surface of the second base material 30 with the eight second front wirings a1 to a8 and the eight second front electrodes y1 to y8 interposed therebetween.

  The second intermediate back side insulating layer 36 is made of acrylic rubber and has a strip shape that is long in the X direction. The second intermediate back side insulating layer 36 is flexible and has an insulating property. The second intermediate back side insulating layer 36 is laminated on the back surface of the second base material 30.

  The two second back-side electrodes x1 and x2 are each formed including acrylic rubber and conductive carbon black. The two second back-side electrodes x1 and x2 are each flexible and conductive. The two second back-side electrodes x1 and x2 are disposed on the back side of the second intermediate back-side insulating layer 36. The two second back-side electrodes x1 and x2 each have a rack shape (straight sawtooth shape) that is long in the X direction. The two second back side electrodes x1 and x2 are arranged side by side in the Y direction. The two second back-side electrodes x1 and x2 are arranged symmetrically with respect to the Y-direction center line L2 of the load sensor unit 3.

  The two second back side wires b1 and b2 are each made of silver paste. Each of the two second back-side wirings b1 and b2 has conductivity. The two second back side wires b1 and b2 cover the back surfaces of the wiring parts of the two second back side electrodes x1 and x2. The two second back side wires b1 and b2 extend over substantially the entire length in the X direction of the two second back side electrodes x1 and x2.

  The second back-side insulating layer 33 is made of urethane rubber and has a strip shape that is long in the X direction. The second back side insulating layer 33 is flexible and has an insulating property. The second back-side insulating layer 33 is laminated on the back surface of the second base material 30 with the two second back-side wirings b1 and b2 and the two second back-side electrodes x1 and x2 interposed therebetween.

  On the back surface of the second front insulating layer 32, eight second front wirings a1 to a8, eight second front electrodes y1 to y8, and a second intermediate front insulating layer 35 are screen-printed. On the surface of the second back side insulating layer 33, two second back side wirings b1 and b2, two second back side electrodes x1 and x2, and a second intermediate back side insulating layer 36 are screen-printed.

  When viewed from the front side or the back side, the eight second front side electrodes y1 to y8 and the two second back side electrodes x1 and x2 overlap in the front and back direction (load transmission direction). That is, as shown by hatching in FIG. 3, a total of 16 overlapping portions α are formed between the second front side electrodes y1 to y8 and the second back side electrodes x1 and x2. That is, eight overlapping portions α are arranged in the X direction. In addition, two overlapping portions α are arranged in the Y direction.

(Proximity sensor part 2)
FIG. 5 shows a Z direction transparent front view of the proximity sensor portion of the sensor stack of the gripping state detection sensor of the present embodiment. FIG. 6 is an exploded front view of the proximity sensor unit in the Z direction. The dashed line in FIG. 5 is the outline of the overlapping portion α of the load sensor unit 3. 6 are the outlines of the second back side electrodes x1 and x2 of the load sensor unit 3. A one-dot chain line surrounding the first back side electrodes Y1 to Y8 in FIG. 6 is an outline of the second front side electrodes y1 to y8 of the load sensor unit 3. The white arrows in FIG. 6 indicate the stacking order. The hatched arrows in FIG. 6 indicate the printing order.

  As shown in FIGS. 5 and 6, the proximity sensor unit 2 includes a first front-side insulating layer 22, two first front-side electrodes X <b> 1 and X <b> 2, and two first first-side electrodes from the Z-direction front side to the Z-direction back side. By stacking the front-side wirings B1 and B2, the first base material 20, the eight first back-side wirings A1 to A8, the eight first back-side electrodes Y1 to Y8, and the first back-side insulating layer 23. Is formed.

  The first base material 20 is made of urethane rubber and has a long band shape in the X direction. The first base material 20 is flexible and has an insulating property.

  The two first front wirings B1 and B2 are each made of silver paste. Each of the two first front-side wirings B1 and B2 has conductivity. The two first front-side wirings B <b> 1 and B <b> 2 are stacked on the surface of the first base material 20.

  The two first front electrodes X1 and X2 are each formed of acrylic rubber and conductive carbon black. The two first front electrodes X1 and X2 are each flexible and conductive. The two first front-side electrodes X1 and X2 are arranged on the front side of the first base material 20 with the two first front-side wirings B1 and B2 interposed therebetween. The two first front electrodes X1, X2 each have a rack shape that is long in the X direction. The two first front electrodes X1 and X2 are arranged side by side in the Y direction. The two first front electrodes X1 and X2 are arranged symmetrically with respect to the Y-direction center line L1 of the proximity sensor unit 2. As shown in FIG. 2, the Y-direction center line L <b> 1 is disposed at the radially outer end of the steering wheel 8. The two first front-side electrodes X1 and X2 and the two second back-side electrodes x1 and x2 overlap in the front-back direction.

  The first front insulating layer 22 is made of urethane rubber, and has a strip shape that is long in the X direction. The first front insulating layer 22 is flexible and has an insulating property. The first front-side insulating layer 22 is laminated on the surface of the first base material 20 with the two first front-side electrodes X1 and X2 and the two first front-side wirings B1 and B2 interposed therebetween.

  The eight first back wirings A1 to A8 are each made of silver paste. Each of the eight first back wirings A1 to A8 has conductivity. The eight first back wirings A <b> 1 to A <b> 8 are stacked on the back surface of the first base material 20.

  The eight first back-side electrodes Y1 to Y8 are each formed including acrylic rubber and conductive carbon black. Each of the eight first backside electrodes Y1 to Y8 is flexible and conductive. The eight first back-side electrodes Y1 to Y8 are arranged on the back side of the first base material 20 with the eight first back-side wirings A1 to A8 interposed therebetween. The eight first back-side electrodes Y1 to Y8 each have a barrel shape that is long in the Y direction. The eight first back electrodes Y1 to Y8 are arranged side by side in the X direction. The eight first back-side electrodes Y1 to Y8 are arranged symmetrically with respect to the Y-direction center line L1 of the proximity sensor unit 2. The eight first back-side electrodes Y1 to Y8 and the eight second front-side electrodes y1 to y8 overlap in the front-back direction.

  The first back-side insulating layer 23 is made of urethane rubber and has a strip shape that is long in the X direction. The first back side insulating layer 23 is flexible and has an insulating property. The first back-side insulating layer 23 is laminated on the back surface of the first base material 20 with the eight first back-side electrodes Y1 to Y8 and the eight first back-side wirings A1 to A8 interposed therebetween.

  On the surface of the first base material 20, two first front wirings B1 and B2, two first front electrodes X1 and X2, and a first front insulating layer 22 are screen-printed. On the back surface of the first base material 20, eight first back wirings A1 to A8, eight first back electrodes Y1 to Y8, and a first back insulating layer 23 are screen-printed.

  FIG. 7 shows an enlarged view of the vicinity of the two overlapping portions α at the left end in the X direction of FIG. As shown in FIG. 7, the first front electrodes X1 and X2 and the first back electrode Y1 have alternating wide portions β1 having a short lateral width and narrow portions β2 having a short lateral width, respectively. Are arranged side by side. The wide portion β1 has a rhombus shape. The narrow portion β2 has a rectangular shape. The narrow portion β2 connects the adjacent wide portions β1 to each other.

  When viewed from the front side or the back side, adjacent wide portions β1 do not overlap in the front and back direction (load transmission direction). That is, as shown by hatching in FIG. 7, the plurality of wide portions β <b> 1 are arranged in a direction in which the front surface or the back surface of the first base material 20 is developed. As indicated by a dotted line in FIG. 7, an electric field γ is formed between adjacent wide portions β1.

(Intermediate part 4)
FIG. 8 is a cross-sectional view in the Z direction (specifically, a cross-sectional view in the VIII-VIII direction in FIGS. 3 and 7) of the sensor stack of the gripping state detection sensor of the present embodiment. As shown in FIGS. 2 and 8, the intermediate portion 4 is disposed between the load sensor portion 3 and the proximity sensor portion 2. The intermediate part 4 includes an intermediate layer 40 and an insulating spacer 41.

  The intermediate layer 40 is disposed behind the proximity sensor unit 2 in the Z direction. The intermediate layer 40 is made of a cloth made of a polyester fiber whose outer surface is coated with a metal, and has a long strip shape in the X direction. The intermediate layer 40 is flexible and has conductivity. The intermediate layer 40 is grounded (grounded).

  The insulating spacer 41 is disposed on the front side of the load sensor unit 3 in the Z direction. The insulating spacer 41 is made of urethane rubber and has a long band shape in the X direction. The insulating spacer 41 is flexible and has an insulating property.

{Controller unit}
FIG. 9 shows a block diagram of the gripping state detection sensor of the present embodiment. As shown in FIG. 9, the control unit 7 includes a control unit 70, a transmission unit 71, a reception unit 72, and a computer 73.

(Control unit 70)
The control unit 70 includes a DSP (Digital Signal Processor) 700 and an SRAM (Static Random Access Memory) 701. The DSP 700 is used as a microcomputer (arithmetic unit). The SRAM 701 is used as a storage unit. The SRAM 701 includes threshold values (approach threshold value, small load threshold value, large load threshold value) for determining approach (non-contact or contact), small load (weak gripping), and large load (strong gripping). ) Is stored. The SRAM 701 stores a map for specifying coordinates in the X direction (see FIG. 1) and the Y direction (see FIG. 2) of the driver's hand H in the proximity sensor unit 2. The SRAM 701 is electrically connected to the DSP 700.

(Transmitter 71)
The transmission unit 71 includes a DAC (Digital-Analog Converter) 710, a DDS (Direct Digital Synthesizer) 711, a multiplexer 712, and two operational amplifiers 713.

  The DAC 710 converts a digital signal into an analog signal. The DAC 710 is electrically connected to the DSP 700. The DDS 711 is used as a sine wave oscillator. The DDS 711 is electrically connected to the DAC 710. The analog multiplexer 712 is electrically connected to the DDS 711. The multiplexer 712 scans and outputs the sine wave current to the two operational amplifiers 713 while sequentially switching them. Each of the two operational amplifiers 713 converts the current input from the multiplexer 712 into a voltage. That is, the two operational amplifiers 713 are each used as a current-voltage converter. The two operational amplifiers 713 are electrically connected to the two first front wirings B1 and B2 and the two first front electrodes X1 and X2.

(Receiver 72)
The receiving unit 72 includes four ADCs (Analog-Digital Converter) 720, four low-pass filters 721, four multiplexers 722, and eight operational amplifiers 723.

  The eight operational amplifiers 723 are electrically connected to the eight first back wirings A1 to A8 and the eight first back electrodes Y1 to Y8. Each of the eight operational amplifiers 723 is used as a current-voltage converter. The four analog multiplexers 722 are electrically connected to the eight operational amplifiers 723. The four multiplexers 722 are connected to the eight operational amplifiers 723 while being sequentially switched. Each of the four low-pass filters 721 cuts a high-frequency component of the voltage. The four low-pass filters 721 are electrically connected to the four multiplexers 722. The four ADCs 720 convert analog signals into digital signals. The four ADCs 720 are electrically connected to the four low-pass filters 721. The four ADCs 720 are electrically connected to the DSP 700.

(Computer 73)
The computer 73 is electrically connected to the DSP 700. The computer 73 transmits a command according to the gripping state (approach, small load input, large load input, etc.) of the driver to an actuator (not shown, for example, an alarm device).

  The control unit 7 is electrically connected to the load sensor unit 3 shown in FIG. 3 as well as the proximity sensor unit 2 shown in FIG. In other words, the voltage is sequentially supplied to the two second back-side wirings b1 and b2 and the two second back-side electrodes x1 and x2 of the load sensor unit 3 sequentially through the multiplexer. Current is output from the eight second front-side wirings a1 to a8 and the eight second front-side electrodes y1 to y8.

[Movement of proximity sensor unit 2 of gripping state detection sensor 1]
Next, the movement of the proximity sensor unit 2 of the gripping state detection sensor 1 of the present embodiment will be described. FIG. 10A shows an enlarged view of the frame X in FIG. 8 in a state where the hand is not approaching. FIG. 10B shows an enlarged view in the state where the hand is approaching, in the frame X of FIG. As shown in FIG. 10A, a capacitance Ca is generated between the first front electrode X1 and the first back electrode Y1 by the voltage supplied from the transmitter 71 shown in FIG.

  As shown in FIG. 10B, when the driver's hand (having conductivity and is grounded via the human body) H approaches the epidermis 81, the first front-side electrode X1 is placed between the hand H. In addition, a capacitance Cb is generated. For this reason, compared with the state where the hand H is not approaching (FIG. 10A), the state where the hand H is approaching (FIG. 10B) is input to the operational amplifier 723 shown in FIG. Current is reduced. Based on the change in current, the DSP 700 calculates the amount of change in capacitance between the first front electrode X1 and the first back electrode Y1.

[Motion of the load sensor 3 of the gripping state detection sensor 1]
Next, the movement of the load sensor unit 3 of the gripping state detection sensor 1 of the present embodiment will be described. FIG. 11A shows an enlarged view in the state where the hand is not pushed in the frame XI in FIG. FIG. 11B shows an enlarged view in the state where the hand is pushed in the frame XI of FIG. As shown in FIG. 11A, when the hand is not pushed in, a load is applied to the second base material 30, the second intermediate front side insulating layer 35, and the second intermediate back side insulating layer 36, which are dielectric layers. Not. The thickness in the Z direction of the second base material 30, the second intermediate front side insulating layer 35, and the second intermediate back side insulating layer 36 corresponds to the inter-electrode distance d between the second front side electrode y1 and the second back side electrode x1. To do.

  Here, as shown in FIG. 8, the members constituting the proximity sensor unit 2 and the intermediate unit 4 are both flexible. For this reason, if a hand is pushed in, the part pressed by the hand among the proximity sensor part 2 and the intermediate part 4 will immerse locally in a back side. That is, the proximity sensor unit 2 and the intermediate unit 4 are not displaced downwards entirely.

  As shown in FIG. 11B, when the hand is pushed in, the second base material 30, the second intermediate front side insulating layer 35, and the second intermediate back side insulating layer 36 are locally compressed by the load F applied from the front side. The For this reason, the inter-electrode distance d between the second front electrode y1 and the second back electrode x1 is shortened. Based on the change in the inter-electrode distance d, the DSP 700 shown in FIG. 9 calculates the amount of change in capacitance between the second front electrode y1 and the second back electrode x1.

[Method for discriminating approach, small load, and large load of gripping state detection sensor 1]
Next, a method for determining the approach, small load, and large load of the gripping state detection sensor 1 of the present embodiment will be described. FIG. 12 shows a flowchart of processing executed by the control unit of the gripping state detection sensor of this embodiment.

  As shown in FIG. 9, the control unit 7 monitors the capacitance of the proximity sensor unit 2 and the capacitance of the load sensor unit 3 at a predetermined sampling period. That is, the DSP 700 shown in FIG. 9 compares the small load threshold th1 stored in the SRAM 701 with the change amount ΔC2 of the capacitance of the load sensor unit 3 at a predetermined sampling period (FIG. 9). 12 S1 (step 1, the same applies to the following), S2).

  As a result of the comparison (hereinafter referred to as “first comparison”), if the change amount ΔC2 is smaller than the small load threshold th1, the DSP 700 determines that no load is applied to the load sensor unit 3 ( S3 in FIG. In this case, the DSP 700 shown in FIG. 9 compares the approach threshold th3 stored in the SRAM 701 with the change amount ΔC1 of the capacitance of the proximity sensor unit 2 (S4 and S5 in FIG. 12).

  As a result of the comparison (hereinafter referred to as “second comparison”), when the change amount ΔC1 is equal to or greater than the approach threshold th3, the DSP 700 approaches the proximity sensor unit 2 (including contact). (S6 in FIG. 12). Further, the DSP 700 specifies the coordinates at which the hand is approaching. The DSP 700 transmits information regarding hand approach and coordinates to the computer 73. The computer 73 transmits a command corresponding to the information from the DSP 700 to the actuator. On the other hand, if the change amount ΔC1 is less than the approach threshold th3 as a result of the second comparison, the DSP 700 determines that the hand is not approaching the proximity sensor unit 2 (S10 in FIG. 12).

  On the other hand, as a result of the first comparison (S2 in FIG. 12), when the amount of change ΔC2 is equal to or greater than the small load threshold th1, the DSP 700 shown in FIG. 9 compares the large load threshold th2 stored in the SRAM 701 with the large load threshold th2. The change amount ΔC2 is compared (S7 in FIG. 12).

  As a result of the comparison (hereinafter referred to as “third comparison”), when the change amount ΔC2 is less than the large load threshold th2, the DSP 700 determines that a small load has been input by hand (S8 in FIG. 12). ). Further, the DSP 700 specifies the coordinates where the hand is pushed. The DSP 700 transmits information regarding the small hand load and coordinates to the computer 73. The computer 73 transmits a command corresponding to the information from the DSP 700 to the actuator. On the other hand, if the change amount ΔC2 is greater than or equal to the large load threshold th2 as a result of the third comparison, the DSP 700 determines that a large load has been input by hand (S9 in FIG. 12). Further, the DSP 700 specifies the coordinates where the hand is pushed. The DSP 700 transmits information regarding the heavy load and coordinates of the hand to the computer 73. The computer 73 transmits a command corresponding to the information from the DSP 700 to the actuator.

  As described above, the gripping state detection sensor 1 of the present embodiment is configured so that “the hand is separated from the gripping state detection sensor 1” or “the gripping state detection sensor” according to the gripping state of the hand with respect to the gripping state detection sensor 1. 1 that the hand is approaching and the approaching coordinates ”,“ the hand load is applied to the gripping state detection sensor 1 and the coordinates that the load is applied ”, and“ the hand is applied to the gripping state detection sensor 1 It can be determined that a large load is applied and coordinates where a load is applied.

[Function and effect]
Next, the effect of the gripping state detection sensor 1 of the present embodiment will be described. As shown in FIG. 2, the gripping state detection sensor 1 according to the present embodiment includes a proximity sensor unit 2 and a load sensor unit 3. As shown in FIGS. 10A and 10B, the proximity sensor unit 2 detects the approach of the driver's hand H to the steering wheel 8 shown in FIG. 1 based on the change in the capacitance Ca. be able to. Further, the proximity sensor unit 2 can detect the coordinates in the X direction and the Y direction of the driver's hand H based on the coordinates where the capacitance Ca has changed. Further, as shown in FIGS. 11A and 11B, the load sensor unit 3 can detect the pushing of the driver's hand H against the steering wheel 8. Thus, according to the gripping state detection sensor 1 of the present embodiment, the approach, push, and coordinates of the driver's hand H with respect to the steering wheel 8 can be detected. That is, the gripping state of the driver with respect to the steering wheel 8 can be detected in detail.

  Further, as shown in FIGS. 6 and 8, the proximity sensor unit 2 includes first front electrodes X1 and X2, a first base material 20, from the Z direction front side (load input side) toward the Z direction back side, First backside electrodes Y1 to Y8. The first front electrodes X1, X2, the first base material 20, and the first back electrodes Y1 to Y8 are all made of an elastomer that is softer than the resin. For this reason, the proximity sensor unit 2 is flexible. Therefore, even if the gripping state detection sensor 1 is arranged on the steering wheel 8, there is little risk of impairing the tactile sensation that the steering wheel 8 originally has. Further, the flexible proximity sensor unit 2 is difficult to disperse the load applied from the driver's hand H in the X direction and the Y direction. For this reason, the detection precision of the coordinate of a X direction and a Y direction is high.

  Further, the flexible proximity sensor unit 2 has high followability to the shape of the steering wheel 8. For this reason, the gripping state detection sensor 1 can be arranged along the shape of the steering wheel 8 with respect to the steering wheel 8 of any shape. Therefore, the versatility with respect to the shape of the steering wheel 8 is high.

  Note that the proximity sensor unit 2 of the gripping state detection sensor 1 of the present embodiment can be used alone without being combined with the load sensor unit 3.

  In addition, a mutual capacitance type capacitive sensor is used as the proximity sensor unit 2 of the gripping state detection sensor 1 of the present embodiment. That is, as shown in FIGS. 10A and 10B, the proximity sensor unit 2 has a capacitance Cb between the first front electrode X1 and the hand H as the driver's hand H approaches. The proximity of the hand H to the steering wheel 8 and the coordinates are detected based on the decrease in the capacitance Ca between the first front electrode X1 and the first back electrode Y1. For this reason, it is easy to cope with multi-touch (multi-point simultaneous contact).

  Further, as shown in FIGS. 11 (a) and 11 (b), according to the load sensor unit 3 of the gripping state detection sensor 1 of the present embodiment, the change in the electrostatic capacity due to the change in the inter-electrode distance d is based on the change. In addition, it is possible to detect the pressing of the hand H (specifically, the presence / absence of pressing, the degree of pressing, the presence / absence of load, the level of load, the value of load, etc.)

  As shown in FIGS. 4 and 8, the load sensor unit 3 includes the second front electrodes y1 to y8, the second base material 30, and the second back electrode x1 from the Z direction front side to the Z direction back side. , X2. The second front-side electrodes y1 to y8, the second base material 30, and the second back-side electrodes x1 and x2 are all made of an elastomer that is softer than the resin. For this reason, the load sensor unit 3 is flexible. Therefore, even if the gripping state detection sensor 1 is disposed on the steering wheel 8, there is little risk of impairing the tactile sensation that the steering wheel 8 originally has.

  Further, the flexible load sensor unit 3 has high followability to the shape of the steering wheel 8. For this reason, the gripping state detection sensor 1 can be arranged along the shape of the steering wheel 8 with respect to the steering wheel 8 of any shape. Therefore, the versatility with respect to the shape of the steering wheel 8 is high.

  As shown in FIGS. 2 and 8, an intermediate layer 40 is interposed between the proximity sensor unit 2 and the load sensor unit 3. The intermediate layer 40 has conductivity. The intermediate layer 40 is grounded. For this reason, the proximity sensor unit 2 and the load sensor unit 3 are not easily affected by the mutual noise. Therefore, the detection accuracy of the proximity sensor unit 2 and the load sensor unit 3 is increased.

  As shown in FIGS. 2 and 8, an insulating spacer 41 is interposed between the proximity sensor unit 2 and the load sensor unit 3. For this reason, the proximity sensor unit 2 and the load sensor unit 3 can be separated in the Z direction. Therefore, it is possible to suppress the generation of stray capacitance between the proximity sensor unit 2 and the load sensor unit 3. Therefore, mutual interference between the proximity sensor unit 2 and the load sensor unit 3 can be reduced, and the detection accuracy is increased.

  Further, as indicated by hatching arrows in FIG. 4, eight second front wirings a <b> 1 to a <b> 8, eight second front electrodes y <b> 1 to y <b> 8, and a second intermediate front insulating layer 35 are provided on the back surface of the second front insulating layer 32. Is screen printed. On the surface of the second back side insulating layer 33, two second back side wires b1 and b2, two second back side electrodes x1 and x2, and a second intermediate back side insulating layer 36 are screen-printed. Therefore, the second front side wirings a1 to a8, the second front side electrodes y1 to y8, the second intermediate front side insulating layer 35, the second back side wirings b1 and b2, the second back side electrodes x1 and x2, and the second intermediate back side insulating layer 36. Can be easily formed. Moreover, formation and arrangement | positioning of these members can be performed simultaneously. Further, the degree of freedom in setting the shape of these members is increased. Moreover, the precision of the shape of these members becomes high. Moreover, relative alignment between these members becomes easy.

  Further, as shown by hatching arrows in FIG. 6, two first front-side wirings B <b> 1 and B <b> 2, two first front-side electrodes X <b> 1 and X <b> 2, and a first front-side insulating layer 22 are formed on the surface of the first base material 20. Screen printed. Further, on the back surface of the first base material 20, eight first back-side wirings A1 to A8, eight first back-side electrodes Y1 to Y8, and a first back-side insulating layer 23 are screen-printed. For this reason, the first front side wirings B1, B2, the first front side electrodes X1, X2, the first front side insulating layer 22, the first back side wirings A1 to A8, the first back side electrodes Y1 to Y8, the first back side insulating layer 23, It can be easily formed. Moreover, formation and arrangement | positioning of these members can be performed simultaneously. Further, the degree of freedom in setting the shape of these members is increased. Moreover, the precision of the shape of these members becomes high. Moreover, relative alignment between these members becomes easy.

<Others>
The embodiment of the grip state detection 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.

  FIG. 13 shows a front view in the Z direction of an insulating spacer of a gripping state detection sensor according to another embodiment. In addition, about the site | part corresponding to FIG. 3, it shows with the same code | symbol. As shown in FIG. 13, a load dispersion suppression groove 410 is disposed around a portion corresponding to the overlapping portion α (indicated by a one-dot chain line hatching) of the insulating spacer 41. The load dispersion suppressing groove 410 is recessed on the back surface of the insulating spacer 41. The load sensor unit of this embodiment detects the coordinates of the driver's hand.

  As shown in FIG. 8, in order to suppress the generation of stray capacitance between the proximity sensor unit 2 and the load sensor unit 3, the thickness of the insulating spacer 41 in the Z direction is preferably thicker. However, when the thickness of the insulating spacer 41 in the Z direction is increased, the load applied from the driver's hand is easily dispersed in the X direction and the Y direction when the insulating spacer 41 is transmitted. For this reason, in the load sensor part 3 on the back side in the Z direction of the insulating spacer 41, the detection accuracy of the coordinates in the X direction and the Y direction is lowered.

  In this regard, the insulating spacer 41 of the gripping state detection sensor of this embodiment includes a load dispersion suppression groove 410. A portion of the insulating spacer 41 where the load dispersion suppression groove 410 is formed has a smaller thickness in the Z direction than a portion where the load dispersion suppression groove 410 is not formed. For this reason, the spring constants in the X direction and the Y direction are reduced. Therefore, it is possible to suppress the load from being dispersed in the X direction and the Y direction.

  When the load dispersion suppressing groove 410 is arranged in the insulating spacer 41, the load applied from the driver's hand is hardly dispersed in the X direction and the Y direction when the insulating spacer 41 is transmitted. Therefore, in the load sensor unit 3, the detection accuracy of the coordinates in the X direction and the Y direction is increased. Moreover, the load detection accuracy is increased. Instead of the load dispersion suppression groove 410, a load dispersion suppression hole that penetrates the insulating spacer 41 in the Z direction may be disposed.

  In the above embodiment, the gripping state detection sensor 1 is disposed on the steering wheel 8 of the vehicle. However, a gripping state detection sensor may be arranged on an airplane control stick, a ship rudder, a bicycle or motorcycle handle, a train lever, or the like. That is, the type of gripped part is not limited.

  The type of the load sensor unit 3 is not particularly limited. It may be a resistance change type sensor that detects depression based on a change (increase or decrease) in electrical resistance, a load cell (strain gauge), a membrane switch that detects depression based on the presence or absence of conduction.

  As the proximity sensor unit 2, the mutual capacitance type (as shown in FIGS. 10A and 10B), the static electricity between the first front electrode X <b> 1 and the first back electrode Y <b> 1 as the hand approaches. A capacitive sensor of a type in which the capacitance Ca decreases) can be used. Further, a self-capacitance type (a type in which the capacitance Ca between the first front electrode X1 and the first back electrode Y1 increases as the hand approaches) can be used.

  In the above embodiment, as shown in FIG. 12, the DSP 700 indicates that “a small load is applied to the gripping state detection sensor 1 and a load is applied to the gripping state detection sensor 1 according to the hand state with respect to the gripping state detection sensor 1. "Coordinates" and "coordinates that a large load is applied from the hand to the gripping state detection sensor 1 and coordinates that the load is applied" were determined. However, the DSP 700 may calculate the load value itself.

  The arrangement pattern of the first front electrodes X1 and X2 and the first back electrodes Y1 to Y8 is not particularly limited. As shown in FIG. 7, it is only necessary that the wide portions β1 are aligned in the plane direction when viewed from the Z direction front side or the Z direction back side. The wide portion β1 may be a hexagonal shape, a polygonal shape such as an octagonal shape, a circular shape, or the like.

  The arrangement pattern of the second front side electrodes y1 to y8 and the second back side electrodes x1 and x2 is not particularly limited. As illustrated in FIG. 3, it is only necessary to form an overlapping portion α between the second front side electrodes y1 to y8 and the second back side electrodes x1 and x2 when viewed from the Z direction front side or the Z direction back side.

  As shown in FIG. 4, in the said embodiment, the 2nd front side wiring a1-a8, the 2nd front side electrodes y1-y8, and the 2nd intermediate | middle front side insulating layer 35 were screen-printed on the 2nd front side insulating layer 32. As shown in FIG. Further, the second back side wirings b1 and b2, the second back side electrodes x1 and x2, and the second intermediate back side insulating layer 36 were screen-printed on the second back side insulating layer 33. However, the second substrate 30 may be screen-printed with the second front wirings a1 to a8, the second front electrodes y1 to y8, and the second front insulating layer 32. Further, the second back side wirings b1 and b2, the second back side electrodes x1 and x2, and the second back side insulating layer 33 may be screen-printed on the second base material 30.

  As shown in FIG. 6, in the said embodiment, 1st front side wiring B1, B2, 1st front side electrode X1, X2, and the 1st front side insulating layer 22 were screen-printed on the 1st base material 20. As shown in FIG. Further, the first back side wirings A1 to A8, the first back side electrodes Y1 to Y8, and the first back side insulating layer 23 were screen-printed on the first base material 20. However, the first front wirings B1 and B2 and the first front electrodes X1 and X2 may be screen-printed on the first front insulating layer 22. Further, the first back side wirings A1 to A8 and the first back side electrodes Y1 to Y8 may be screen-printed on the first back side insulating layer 23.

  Moreover, you may use inkjet printing, flexographic printing, gravure printing, pad printing, lithography, dispenser printing, etc. instead of screen printing. Moreover, you may produce the proximity sensor part 2 and the load sensor part 3 by adhere | attaching each member shape | molded previously.

  Further, the first front wirings B1 and B2, the first back wirings A1 to A8, the second front wirings a1 to a8, and the second back wirings b1 and b2 may not be arranged.

  The material of the elastomer used for the first base material 20 and the second base material 30 is not particularly limited. The elastomer may contain one or more selected from silicone rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, epichlorohydrin rubber, chlorosulfonated polyethylene, chlorinated polyethylene, and urethane rubber. If it carries out like this, the dielectric constant of the 1st substrate 20 and the 2nd substrate 30 will become high. For this reason, an electrostatic capacitance can be enlarged.

  The material of the elastomer used for the first front electrodes X1, X2, the first back electrodes Y1-Y8, the second front electrodes y1-y8, and the second back electrodes x1, x2 is not particularly limited. Elastomers include 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, etc. May be included.

  The material of the conductive filler used for the first front electrodes X1 and X2, the first back electrodes Y1 to Y8, the second front electrodes y1 to y8, and the second back electrodes x1 and x2 is not particularly limited. The conductive filler may be one or more selected from carbon materials and metals. As the metal, highly conductive silver, copper, or the like is preferable. Therefore, 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 gripping state detection sensor 1 can be reduced. Examples of the carbon material include conductive carbon black, carbon nanotubes, carbon nanotube derivatives, graphite, and conductive carbon fibers. 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 gripping state detection sensor 1 can be reduced.

  The material of the elastomer used for the first front side insulating layer 22, the first back side insulating layer 23, the second front side insulating layer 32, the second back side insulating layer 33, the second intermediate front side insulating layer 35, and the second intermediate back side insulating layer 36 is There is no particular limitation. The elastomer may include acrylic rubber, urethane rubber, silicone rubber, ethylene propylene copolymer rubber, natural rubber, styrene-butadiene rubber, acrylonitrile butadiene rubber, epichlorohydrin rubber, chlorosulfonated polyethylene, chlorinated polyethylene rubber, and the like. .

  Further, as the conductive fiber for the intermediate layer 40, a fiber containing the conductive filler may be used. Further, the intermediate layer 40 may be made of woven fabric, knitted fabric, non-woven fabric, elastomer, or the like, and may be one in which a conductive paint is applied to the outer surface thereof.

  Further, the conductive coating such that the intermediate layer 40 itself is used for, for example, the first front side electrodes X1, X2, the first back side electrodes Y1-Y8, the second front side electrodes y1-y8, the second back side electrodes x1, x2, etc. It may be made. In this case, the intermediate layer 40 may be applied (for example, screen printing) to the first back side insulating layer 23 and the insulating spacer 41.

1: A gripping state detection sensor.
2: proximity sensor part, 20: first base material, 22: first front side insulating layer, 23: first back side insulating layer.
3: load sensor part, 30: second base material, 32: second front side insulating layer, 33: second back side insulating layer, 35: second intermediate front side insulating layer, 36: second intermediate back side insulating layer.
4: intermediate part, 40: intermediate layer, 41: insulating spacer, 410: load dispersion suppressing groove.
6: Sensor laminate.
7: control unit, 70: control unit, 700: DSP, 701: SRAM, 71: transmission unit, 710: DAC, 711: DDS, 712: multiplexer, 713: operational amplifier, 72: reception unit, 720: ADC, 721: Low-pass filter, 722: multiplexer, 723: operational amplifier, 73: computer.
8: Steering wheel, 80: Core, 81: Epidermis.
α: overlapping part, β1: wide part, β2: narrow part, γ: electric field, A1 to A8: first backside wiring, B1, B2: first front side wiring, Ca: capacitance, Cb: capacitance, ΔC1: change amount, ΔC2: change amount, F: load, H: hand, L1, L2: Y direction center line, X1, X2: first front side electrode, Y1 to Y8: first back side electrode, a1 to a8: first Two front side wirings, b1, b2: second back side wiring, d: distance between electrodes, th1: small load threshold, th2: large load threshold, th3: approach threshold, x1, x2: second back side electrode , Y1 to y8: second front side electrodes.

Claims (7)

A gripping state detection sensor disposed in a gripped portion of a vehicle gripped and operated by a driver,
A first substrate made of elastomer having insulation properties;
A plurality of first front electrodes arranged on the front side of the first substrate and made of an electrically conductive elastomer;
A plurality of first backside electrodes disposed on the back side of the first substrate and made of an electrically conductive elastomer;
With
A proximity sensor for detecting the approach and coordinates of the driver with respect to the gripped part based on the change in capacitance between the first front electrode and the first back electrode as the driver approaches And
A load sensor unit that is disposed on the back side of the proximity sensor unit, and detects a push of the driver with respect to the gripped unit based on a load applied from the driver via the proximity sensor unit;
A gripping state detection sensor comprising: The proximity sensor unit is
Capacitance is generated between the first front electrode and the driver as the driver approaches, and the capacitance between the first front electrode and the first back electrode decreases. The gripping state detection sensor according to claim 1, wherein the driver's approach to the gripped part and coordinates are detected based on the gripped part. The load sensor unit is
A second substrate made of elastomer having insulation properties;
A plurality of second front electrodes arranged on the front side of the second base material and made of an elastomer having conductivity;
A plurality of second backside electrodes disposed on the back side of the second substrate and made of an electrically conductive elastomer;
With
Based on the fact that the load reduces the inter-electrode distance between the second front electrode and the second back electrode, and increases the capacitance between the second front electrode and the second back electrode. The gripping state detection sensor according to claim 1, wherein the driver's pushing against the gripped portion is detected.   The grip state detection sensor according to claim 3, further comprising an intermediate layer disposed between the proximity sensor unit and the load sensor unit and having conductivity and grounding.   The grip state detection sensor according to claim 4, wherein the grip state detection sensor is provided on at least one of the front and back sides of the intermediate layer and has an insulating insulating spacer made of elastomer. The proximity sensor unit includes an elastomer first front insulating layer disposed on the front side of the plurality of first front electrodes, and an elastomer first back insulating layer disposed on the back side of the plurality of first back electrodes. And comprising
The load sensor section includes an elastomer-made second front-side insulating layer disposed on the front side of the plurality of second front-side electrodes, and an elastomer-made second back-side insulating layer disposed on the back side of the plurality of second back-side electrodes. And comprising
The gripping state detection sensor according to any one of claims 3 to 5, wherein at least one of the following (a) and (b) is satisfied.
(A) In the proximity sensor unit, the first front electrode is printed on at least one of the first base material and the first front insulating layer, and the first back electrode is the first It is printed on at least one of the base material and the first backside insulating layer.
(B) In the load sensor unit, the second front electrode is printed on at least one of the second base material and the second front insulating layer, and the second back electrode is It is printed on at least one of the base material and the second back side insulating layer.   The gripping state detection sensor according to any one of claims 1 to 6, wherein the gripped portion is a steering wheel.

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