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EP-3923310-B1 - CAPACITIVE COUPLING SENSOR

EP3923310B1EP 3923310 B1EP3923310 B1EP 3923310B1EP-3923310-B1

Inventors

  • MINOSHIMA, RYO
  • KATAYAMA, KAZUTAKA
  • FUKUTA, TOMOHIRO

Dates

Publication Date
20260506
Application Date
20191219

Claims (10)

  1. A capacitive coupling sensor (1), comprising: a sensor unit (10), comprising a detection electrode layer (11) which generates capacitance between the detection electrode layer (11) and a detection target, a shield electrode layer (12), and an insulation layer (13) which is arranged between the detection electrode layer (11) and the shield electrode layer (12), the detection electrode layer (11) is embedded in the insulation layer (13), and the shield electrode layer (12) is embedded in the insulation layer (13), wherein the insulation layer (13) has a cross-linked polymer obtained by cross-linking of a thermoplastic polymer, wherein the detection electrode layer (11) and the shield electrode layer (12) are made of a conductive cloth.
  2. The capacitive coupling sensor (1) according to claim 1, wherein a thickness of the insulation layer (13) is 0.1 mm or more and 1 mm or less.
  3. The capacitive coupling sensor (1) according to claim 1 or 2, wherein the insulation layer (13) has an insulation particle having thermal conductivity of 20 W/m·K or more.
  4. The capacitive coupling sensor (1) according to any one of claims 1 to 3, further comprising a heater layer (30, 32), wherein, with a lamination direction from the detection electrode layer (11) toward the shield electrode layer (12) in the sensor unit defined as a front and back direction, the heater layer is arranged on a back side of the sensor unit (10), and the heater layer (30, 32) has a heat source and a cross-linked polymer obtained by cross-linking of a thermoplastic polymer.
  5. The capacitive coupling sensor (1) according to claim 4, wherein at least a part of the shield electrode layer (12) is embedded in the heater layer (30, 32).
  6. The capacitive coupling sensor (1) according to any one of claims 1 to 5, further comprising a skin layer (40, 42), wherein, with the lamination direction from the detection electrode layer (11) toward the shield electrode layer (12) in the sensor unit (10) defined as a front and back direction, the skin layer (40, 42) is arranged on a front side of the sensor unit (10), and the skin layer (40, 42) has a cross-linked polymer obtained by cross-linking of a thermoplastic polymer.
  7. The capacitive coupling sensor (1) according to claim 6, wherein at least a part of the detection electrode layer (11) is embedded in the skin layer (40, 42).
  8. The capacitive coupling sensor (1) according to any one of claims 1 to 3, further comprising a skin layer (40, 42) and a heater layer (30, 32), wherein, with the lamination direction from the detection electrode layer (11) toward the shield electrode layer (12) in the sensor unit (10) defined as a front and back direction, the skin layer (40, 42) is arranged on a front side of the sensor unit (10), the heater layer (30, 32) is arranged on a back side of the sensor unit (10) and has a heat source, and the insulation layer (13), the skin layer (40, 42), and the heater layer (30, 32) have the same cross-linked polymer.
  9. The capacitive coupling sensor (1) according to any one of claims 1 to 8, wherein the thermoplastic polymer has an olefin-based resin or an elastomer.
  10. The capacitive coupling sensor (1) according to any one of claims 1 to 9, which is arranged in a steering wheel (8).

Description

BACKGROUND Technical Field The present disclosure relates to a capacitive coupling sensor which is arranged in a steering wheel, interior components, and the like of a vehicle and is capable of detecting proximity, contact, and the like of a person. Related Art Various sensors that detect the state of an occupant are mounted on vehicles such as automobiles and the like. For example, Patent literatures 1 to 3 disclose a contact sensor which is arranged in a rim unit (a grip) of a steering wheel. The contact sensor includes a detection electrode layer and a shield electrode layer, and detects whether or not a driver is in contact with the steering wheel based on the change in capacitance generated between the occupant and the detection electrode layer. On the other hand, the rim unit becomes cold in winter and in cold regions. A steering wheel in which a heater is attached to the rim unit is known in order to reduce the difficulty of driving and the discomfort caused by the cold rim unit. In the steering wheel described in Patent literatures 1 to 3, the heater is arranged on a lower side (a core body side) of the contact sensor. Patent literature 5 relates to compressible, multilayer articles useful in force sensing capacitors. Patent literature 6 describes a resin composition for printed circuit board which contains a thermosetting resin and an inorganic filler containing magnesium oxide. Patent literature 7 describes an insulating board comprising a first surface layer and an intermediate layer. [Literature of related art] [Patent literature] Patent literature 1: Japanese Patent Laid-Open No. 2014-190856Patent literature 2: International Publication No. WO 2014/123222Patent literature 3: Japanese Patent Laid-Open No. 2016-165940Patent literature 4: Japanese Patent Laid-Open No. 2017-84783Patent literature 5: US 2018/134010 A1Patent literature 6: US 2015/366056 A1Patent literature 7: DE 11 2015 003461 T5 SUMMARY The claimed invention is defined by the independent claims, while preferred embodiments form the subject of the dependent claims. [Problems to be Solved] FIG. 5 shows a radial cross-sectional view of a conventional steering wheel including a contact sensor and a heater layer. As shown in FIG. 5, a steering wheel 9 includes a core body 20, a heater layer 30, a contact sensor 90, and a skin layer 40. The steering wheel 9 has a lamination structure in which a plurality of layers are laminated from the core body 20 toward the outside in the radial direction. The heater layer 30 covers an outer peripheral surface of the core body 20. The contact sensor 90 covers an outer peripheral surface of the heater layer 30. The skin layer 40 covers an outer peripheral surface of the contact sensor 90. The driver touches the skin layer 40. The contact sensor 90 has a detection electrode layer 91, a shield electrode layer 92, and an insulation layer 93. The detection electrode layer 91 is arranged on the skin layer 40 side, and generates capacitance between the detection electrode layer 91 and the driver's hand (a detection target). The shield electrode layer 92 is arranged on the heater layer 30 side, and shields noise from the heater layer 30. The insulation layer 93 is arranged between the detection electrode layer 91 and the shield electrode layer 92. An adhesive layer 94 is arranged between the detection electrode layer 91 and the insulation layer 93. An adhesive layer 95 is arranged between the shield electrode layer 92 and the insulation layer 93. The adhesive layers 94 and 95 adhere two adjacent layers. Similarly, an adhesive layer 31 is arranged between the heater layer 30 and the shield electrode layer 92. The adhesive layer 31 adheres the heater layer 30 and the shield electrode layer 92. An adhesive layer 41 is arranged between the skin layer 40 and the detection electrode layer 91. The adhesive layer 41 adheres the skin layer 40 and the detection electrode layer 91. For example, as described in Patent literature 4, the heater layer 30 is configured by arranging a heating wire of a heat source on a nonwoven fabric or the like. Because the contact sensor 90 is adjacent to the heater layer 30, it is desirable to improve heat resistance from the viewpoint of fail-safe. In addition, the contact sensor 90 is preferably as thin as possible from the viewpoint of improving the ease of gripping the steering wheel 9. Furthermore, it is also important that the heat from the heater layer 30 is efficiently transferred to the skin layer 40. In consideration of the feeling when the driver grips the steering wheel 9, a foamed resin such as a polyethylene foam or the like is used in the insulation layer 93 of the contact sensor 90. However, the heat resistance and the thermal conductive property of the foamed resin are not sufficient. In addition, if the foamed resin is made thinner, the insulation property may be lowered and the function of the sensor may be inhibited, and thus a certain degree of thickness is required fo