CN111148652B

CN111148652B - Sensor mat providing shielding and heating

Info

Publication number: CN111148652B
Application number: CN201780095376.7A
Authority: CN
Inventors: 布莱妮·J·多尔切蒂; 菲利普·B·玛桂尔
Original assignee: Joyson Security Systems Acquires LLC
Current assignee: Joyson Security Systems Acquires LLC
Priority date: 2017-07-28
Filing date: 2017-07-28
Publication date: 2022-11-04
Anticipated expiration: 2037-07-28
Also published as: WO2019022765A1; DE112017007711T5; CN111148652A

Abstract

According to various embodiments, a sensor pad is disclosed that includes a pad substrate, a sensor electrode, and a shield electrode. On the first surface of the pad substrate, at least a portion of the sensor electrode and at least a portion of the shield electrode are spaced apart from and parallel to each other. The shield electrode is electrically connected to a voltage source to generate a capacitance between the shield electrode and the sensor electrode, and the sensor electrode is used to detect a change in the capacitance. The shielding electrodes may also be used alternately to heat the surface of the vehicle component in the vicinity of the mat. For example, the sensor may be disposed adjacent a portion of a steering wheel or seat assembly and used to sense the presence of a hand or body of an occupant adjacent the steering wheel or seat assembly.

Description

Sensor mat providing shielding and heating

Cross Reference to Related Applications

Is composed of

Background

Current heating and sensing systems for vehicles include a multi-layer mat that includes a heater mat for heating a surface adjacent the heater mat, a separate sensing mat for sensing the presence of an occupant adjacent the sensing mat, and a shielding mat disposed between the sensing mat and a frame of the vehicle component on which the sensing mat and heating mat are disposed. The shielding pad prevents parasitic capacitance from being generated between the frame and the sensing pad. However, placing multiple pads around a vehicle component is cumbersome to manufacture and requires additional cost and material.

Accordingly, there is a need in the art for an improved sensor mat that is capable of heating and avoiding the creation of parasitic capacitance of the frame of the vehicle component adjacent thereto.

Disclosure of Invention

According to various embodiments, a sensor pad disclosed herein includes a pad substrate, a sensor electrode, and a shield electrode. At least a portion of the sensor electrodes and at least a portion of the shield electrodes are spaced apart from and parallel to each other in a common plane on the first surface of the pad substrate. The shield electrode is electrically connected to a voltage source to generate a capacitance between the shield electrode and the sensor electrode, and the sensor electrode is used to detect a change in the capacitance. For example, the sensor electrodes sense changes in capacitance in response to the presence of a conductive object (e.g., a human hand) on or adjacent to the sensor electrodes. In some embodiments, the sensor mat may be wrapped around the edge of the steering wheel assembly, placed under an airbag cover or flap of the steering wheel assembly, or placed under a seat cover in the vehicle to detect the presence of an occupant and/or the occupant touching the steering wheel assembly adjacent the sensor mat.

Other various embodiments include a method of sensing operator contact with a portion of a vehicle. The method comprises the following steps: (1) providing a sensor mat adjacent a portion of a vehicle; (2) Controlling a voltage source to flow a first current through a shield electrode of a sensor pad to shield the sensor electrode from parasitic capacitance; and (3) controlling the voltage source to flow a second current through the shield electrode to heat the sensor pad. Wherein the second current is greater than the first current. The sensor pad includes a pad substrate, a sensor electrode disposed adjacent a first surface of the pad substrate, and a shield electrode disposed adjacent the first surface of the pad substrate. At least a portion of the shield electrode is spaced apart from and parallel to and in the same plane as at least a portion of the sensor electrode, and the shield electrode is electrically connected to a voltage source to create a capacitance between the shield electrode and the sensor electrode. The sensor electrodes are used to detect changes in capacitance.

Drawings

These and other features, aspects, and advantages of the present invention will become apparent from the following description and the accompanying exemplary embodiments shown in the drawings, which are briefly described below.

Fig. 1 shows a top view of a sensor mat according to an embodiment.

FIG. 2A shows a cross-sectional view of the sensor pad of FIG. 1 taken through line 2A-2A.

FIG. 2B shows a cross-sectional view of the sensor pad of FIG. 1 taken through line 2B-2B.

Fig. 3 shows a top view of a sensor mat according to another embodiment described herein.

Fig. 4A shows a schematic electrical diagram according to an embodiment.

FIG. 4B shows a logic table implementing the circuit of FIG. 4A as described herein.

Detailed Description

According to various embodiments, the sensor pad includes a pad substrate 12, a sensor electrode 14, and a shield electrode 16. At least a portion of the sensor electrode 14 and at least a portion of the shield electrode 16 are spaced apart from and parallel to each other on the first surface 18 of the pad substrate 12 in a plane. The shield electrode 16 is electrically connected to a voltage source within the system circuitry to generate a capacitance between the shield electrode 16 and the sensor electrode 14, and the sensor electrode 14 is used to detect a change in capacitance between the electrodes. For example, the sensor electrode detects a change in capacitance in response to the presence of a conductive object (e.g., a human hand) on or near a portion of the sensor electrode parallel to the shield electrode. In some embodiments, the sensor mat 10 may be wrapped around the edge of the steering wheel assembly, placed under an airbag cover or flap of the steering wheel assembly, or placed under a seat cover in the vehicle to detect the presence of an occupant and/or the occupant touching the steering wheel assembly adjacent the sensor mat. The sensor mat described herein reduces the number of layers that need to be sensed and the number of layers that can be heated along a portion of the vehicle surface.

The detection system disclosed herein (e.g., the system of fig. 4A) may include a microcontroller 401 or any processor or Electronic Control Unit (ECU) that controls occupant detection and receives various measurements from system components (e.g., sensor electrodes 414, heater/shield electrodes 416, and associated switches 408, 410). The microcontroller 401 may be configured to interact with other vehicle systems, such as with vehicle safety systems (e.g., airbag and seat belt systems). The microcontroller may provide signals to other vehicle safety systems or auxiliary systems to monitor the vehicle occupant's experience in the vehicle. The microcontroller 401 used herein for occupant detection analysis may be integrated with a separate controller of another vehicle system (e.g., a controller for a vehicle safety system).

The

electrodes

414, 416 may be configured as shown in accordance with the

exemplary electrodes

14, 16 shown in greater detail in fig. 1 and 2A, 2B. These figures show one embodiment of a sensor mat 10 comprising a sensor electrode 14 and a shield/heater electrode 16. The sensor pad 10 includes a pad substrate 12, a sensor electrode 14, and a shield electrode 16. The pad substrate 12 has a first plane 18, and the sensor electrode 14 and the shield electrode 16 are disposed on the first plane 18. In some embodiments, the capacitance discussed in this disclosure is the capacitance between the sensor electrode 14 and the shield electrode 16, and the spacing 23 between the electrodes presents a capacitance when a voltage is applied to one of the electrodes, typically the shield electrode 16, 416 (fig. 4). In other embodiments, the dielectric material 22 may be disposed on the first planar surface 18 and/or between the

electrodes

14, 16. For example, the dielectric material 22 shown in FIG. 2A overlies the

electrodes

14, 16 and between the

electrodes

14, 16 at points where the structure of the system requires the electrode paths to intersect. In other non-limiting embodiments, the dielectric 22 may also extend over the first planar surface 18 of the pad substrate 12 on which the

electrodes

14, 16 are disposed.

In the arrangement shown in fig. 1, the pad substrate 12 has an outer perimeter 13, the outer perimeter 13 including a first end 11 and a second end 15 spaced from the first end 11. The first side 7 and the second side 9 are also opposite each other and are connected to the

ends

11, 15 of the mat base 12 to complete the perimeter 13. In some embodiments of the present disclosure, the components are described as being positioned relative to one another, and convenience is provided by providing a horizontal reference point by considering the first surface 18 of the pad substrate, without limiting the scope of the embodiments. The objects on the substrate may extend laterally along a horizontal axis from the first side 7 to the second side 9 or longitudinally from the first end 11 to the second end 15. The components on the substrate may be considered to have a height or thickness determined by the dimension extending vertically from the first surface 18 of the pad substrate 12.

One feature of the disclosed object sensing system is that the electrical components on the substrate, particularly the sensor electrodes 14 and the shield electrodes 16, are disposed in a non-overlapping pattern, which may be considered concentric, at least along at least a portion of the mat substrate 12. In the non-limiting example of fig. 1, the shield electrode 16 includes an outer portion 16a operatively connected to an inner portion 16 b. The outer portion 16a defines a boundary adjacent the periphery 13 of the pad substrate 12. In the embodiment shown in FIG. 1, the outer portion 16a defines a generally U-shaped boundary. The inner portion 16b of the shield electrode 16 is spaced inwardly from the outer portion 16a and is spaced apart from the outer portion 16a. In the embodiment shown in fig. 1, the inner portion 16b is also rectangular. The two leads 1ic, 1qd of the shield electrode 16 extend between the junctions of the outer 16a and inner 16b portions to the first end 11 of the pad substrate 12. Leads 1ic, 1qd are coupled to controller 20.

The sensor electrode 14 also includes an outer portion 14a and an inner portion 14b. The outer portion 14b is disposed between the inner portion 16b and the outer portion 16a of the shield electrode 16, and the inner portion 14b is disposed between inner regions constituting the shield inner portion 16 b. Two leads 14c,14d of the sensor electrode 14 extend between the junction of the outer 14a and inner 14b to the first end 11 of the pad substrate 12. Leads 14c,14d are coupled to the controller 20. Portions of the sensor electrode 14 and portions of the shield electrode 16 intersect near the first end 11 with a dielectric material 22 disposed between these portions. In other words, the shield electrode 16 and the sensor electrode 14 comprise electrode portions alternating at intermediate intervals 23 from side 7 to side 9 from shield electrode portion to sensor electrode portion. In other embodiments, this lateral arrangement of alternating sensing and shielding electrode portions may be easily arranged from one end to the other.

Along the wires of other embodiments, shield electrodes 16 and sensor electrodes 14 may be arranged in other non-rectangular arrangements, such as the sinusoidal arrangement shown in FIG. 3. Fig. 3 shows how the sensor electrode 14 and the shield/heater electrode 16 are positioned in a laterally offset relationship in a horizontal plane, wherein in fig. 1 the upper surface 18 of the sensor pad 10 is considered to be the horizontal plane and laterally offset between the first side 7 and the second side 9. The sensor pad surface supports the electrodes and extends laterally between portions of the electrodes. Other non-overlapping shapes of the sensor electrode 14 and the shield electrode 16 are also within the scope of the present disclosure and will result in a substantially flat arrangement of the sensor and shield system on the sensor mat 10 as disclosed. By placing sensor electrode 14 and shield electrode 16 in a common plane, sensor pad 10 may be configured for use in more locations of the vehicle without increasing the bulk, non-uniformity, and/or unnecessary thickness of the sensing system. The sensor mat 10 is also configured for wrapping around a vehicle component, such as a steering wheel in a vehicle. In this embodiment, the sensor mat 10 and

sensors

14, 16 are sufficiently flexible to bend and wrap without losing sensing, shielding and/or heating functionality, while properly accounting for capacitance between the electrodes. The embodiments of the present disclosure in which the

electrodes

14, 16 are referred to as being in a common plane are not meant to be limiting in any way, but rather the planes discussed herein emphasize that the location of the

electrodes

14, 16 on the pad 10 results in a flat placement sensor, wherein the sensor has a parallel and possibly uniform thickness or height dimension, which can be placed perpendicular to the upper surface 18 of the pad.

In some embodiments, the sensor electrodes 14 and the shield electrodes 16 are wires coupled to the pad substrate 12, such as by sewing them to the pad substrate 12, adhering them (e.g., gluing) to the pad substrate 12, or printing conductive ink onto the first planar surface 18 of the pad substrate 12. The sensor electrode 14 and the shield electrode 16 may also be any generally flat, flexible, elongated conductor, such as a conductor in the form of a strip or other shape that facilitates a concentric pattern on the pad 10. Fig. 1 shows that the spacing between the sensor electrode 14 and the shield electrode 16 on the pad 10 is sized and configured to create a capacitance between the non-overlapping portions of the sensor electrode 14 and the shield electrode 16 due to the electric field induced within the spacing 22.

As shown in the embodiment of fig. 4A, the capacitance may be induced when the sensor electrode 14 and the shield electrode 16 are coupled to a controller 20 that provides a voltage source to the shield electrode 16 and receives a capacitance signal from the sensor electrode 14. The voltage source may be controlled by the controller 20 to cause either a first current or a second current to flow through the shielding electrode 16. The voltage applied to the shield electrode 16 creates a capacitance between the shield electrode 16 and the sensor electrode 14. The signals received by the controller 20 from the sensor electrodes 14 may detect a change in capacitance in the sensor electrodes 14, which may be used to determine the presence of an occupant or a portion of an occupant's body in proximity to the sensor mat 10. The first current protects the sensor electrode 14 from parasitic capacitance from the vehicle component frame or other conductive material that is not intended to be sensed by the sensor electrode 14, and the second current heats the sensor pad 10. Wherein the first current is less than the second current. For example, the first current may be less than 5mA, and the second current may be between 5A and 10A. FIG. 4B illustrates a logic table that may be used in one non-limiting embodiment to provide heating, shielding, and sensing operations, which are switched as shown to implement embodiments of the present disclosure.

It is noted that the embodiments of fig. 4A and 4B incorporate certain object presence sensor technologies by which sensor electrodes 14 are consistently configured to sense touches from vehicle occupants, conductive objects in close proximity to sensor electrodes 14 (including live occupants), or conductive objects in direct or indirect contact with sensor electrodes 14. The system described herein is operable when the occupant is indirectly touching or touching, i.e., there is a layer of material such as seat cover or steering wheel leather between the occupant and the actual electrode. In addition, the system electronics can track the capacitance displayed around the sensor electrode when there is any signal on the shield electrode, whether heating or a shield signal. However, the logical operation of the software programmed into the microcontroller 401 shown in fig. 4A ensures greater accuracy in sensing the presence of an occupant during certain time periods and providing the occupant's desired heating function during other time periods. The embodiments presented herein include all available options for data signal transmission and data multiplexing options for sensing, heating and shielding control signals, as well as various outputs on the shield sensor 16 to periodically switch between heating and shielding over a period of time while the occupant is engaged in the steering wheel or other portion of the vehicle. In yet another non-limiting example, switching between shielding and heating may occur along known and periodic time intervals programmed into the microcontroller control system. As shown in fig. 4A, the microcontroller provides input and output control signals 403, 412, 414 to activate the sensing, shielding and heating functions via sensor circuit 405 and heater circuit 406, respectively, with sensor circuit 405 and heater circuit 406 connected to the electrodes via appropriate circuitry for communicating with sensing signal 403, shielding signal 416 and heater signal 418.

In some embodiments, the shield electrode 16 is grounded to provide a reference value when modeling the capacitive response of the

sensor electrode

14, 414 and the

shield electrode

16, 416. Grounding of the shield electrode 16 will create a compensation capacitance between the sensor electrode 14 and the shield electrode 16 that operates in parallel with the variable capacitance being measured. This compensation capacitance shown as an example in fig. 3 can be eliminated as a known constant offset. Also shown in fig. 3, when the shield/

heater electrode

16, 416 is grounded, the electrodes may be configured to bridge between the sensor electrode 14 and the shield electrode 16, thereby generating a larger capacitive signal when a conductive body part (e.g., a finger) is applied to the

electrodes

14, 16.

The distance between the parallel portions of the shield electrode 16 and the sensor electrode 14 is selected to increase the sensitivity of the capacitive signal. For example, an exemplary spacing range is between 1mm and 7 mm.

In some embodiments, the sensor mat 10 is flexible. For example, the pad substrate 12 may be made of a flexible material, such as leather or vinyl skin, mounted on a steering wheel assembly or a seat assembly. Other exemplary materials include any non-conductive material, such as foam, felt, PET, and the like. The layer of dielectric material 22, which may be disposed in the material of the mat substrate 12 or on the first surface 18 thereof, may also be sufficiently flexible to meet the requirements of a hand-mounted installation. Any non-conductive material may be used as dielectric material 22, including ambient air between sensor electrode 14 and shield electrode 16.

As described above, the single layer configuration of the systems described herein may reduce the distance between the electrode and the surface of the vehicle component, which improves sensing and heating capabilities.

The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.

Claims

1. A sensor mat, comprising:

a pad substrate;

a sensor electrode disposed adjacent to the first surface of the pad substrate, at least a portion of the sensor electrode being disposed in a plane; and

a shield electrode disposed adjacent the first surface of the pad substrate, at least a portion of the shield electrode being spaced apart from, parallel to, and in the same plane as at least a portion of the sensor electrode,

wherein the sensor electrode comprises a sensing signal thereon and the shield electrode comprises a voltage thereon,

wherein the sensor electrode is to detect a change in a variable capacitance between the sensor electrode and the shield electrode; and

the sensor electrode also senses a conductive object in close proximity or direct contact with the sensor electrode;

wherein the distance between the shielding electrode and the parallel portion of the sensor electrode is selected to improve the sensitivity of the capacitance signal.

2. The sensor mat of claim 1, wherein a voltage source is controllable to cause a first current or a second current to flow through the shield electrode, the first current being less than the second current.

3. The sensor mat of claim 2, wherein the second current heats the sensor mat and the first current shields the sensor electrode from parasitic capacitance.

4. The sensor mat of claim 1, wherein the sensor electrode and the shield electrode are wires coupled to the mat substrate.

5. The sensor mat of claim 4, wherein the sensor electrodes and the shield electrodes are printed conductive ink printed on the mat substrate.

6. The sensor mat of claim 1, wherein at least one dielectric material is disposed adjacent to the sensor electrode and the shield electrode.

7. The sensor mat of claim 6, wherein at least a portion of the mat substrate comprises the dielectric material.

8. The sensor mat of claim 1, wherein the shield electrode defines a boundary and the sensor electrode is disposed within the boundary;

the sensor pad further comprises:

the shield electrode crosses a point of the sensor electrode; and

a dielectric material located between the sensor electrode and the grounded shield electrode.

9. The sensor mat of claim 1, wherein the sensor mat is flexible.

10. A method of sensing an operator contact with a portion of a vehicle, the method comprising: disposing a sensor mat adjacent a portion of the vehicle, the sensor mat comprising:

a pad substrate;

a sensor electrode disposed adjacent to the first surface of the pad substrate, at least a portion of the sensor electrode disposed in a plane, wherein the sensor electrode includes a sensing signal thereon; and

wherein the distance between the shield electrode and the parallel portion of the sensor electrode is selected to improve the sensitivity of the capacitive signal;

wherein the shield electrode is electrically connected to a voltage source to generate a variable capacitance between the shield electrode and the sensor electrode, the sensor electrode to detect a change in the variable capacitance; and the sensor electrode also senses a conductive object in close proximity or direct contact with the sensor electrode;

controlling the voltage source to flow a first current through the shield electrode to shield the sensor electrode from parasitic capacitance; and

controlling the voltage source to flow a second current through the shield electrode to heat the sensor pad, the second current being greater than the first current.

11. The method of claim 10, wherein the sensor electrode and the shield electrode are wires coupled to the pad substrate.

12. The method of claim 11, wherein the sensor electrode and the shield electrode are printed conductive ink printed on the pad substrate.

13. The method of claim 10, wherein at least one dielectric material is disposed adjacent to the sensor electrode and the shield electrode.

14. The method of claim 13, wherein at least a portion of the pad substrate comprises the dielectric material.

15. The method of claim 10, wherein the shield electrode defines a boundary and the sensor electrode is disposed within the boundary.

16. The method of claim 10, wherein the sensor mat is flexible.