Integrated Sensor Mat Shielding and Heating
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Solution Overview
Problem
Current heating and sensing systems in vehicles require multiple layers of mats, including a heater mat, a sensing mat, and a shielding mat, which are cumbersome to manufacture and costly, and fail to effectively avoid parasitic capacitance between the sensing mat and the vehicle frame.
Innovation Solution
A single sensor mat with a mat substrate, a sensor electrode, and a shield electrode spaced apart and parallel to each other, where the shield electrode is electrically coupled to a voltage source to create capacitance and detect changes, also capable of heating by controlling current flow, thereby reducing the need for additional layers and preventing parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple layers of mats (heater mat, sensing mat, shielding mat) are used, then heating and sensing functions are provided, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the heater mat, sensing mat, and shielding mat into a single integrated sensor mat. The mat substrate includes both sensor electrodes for capacitance sensing and heater electrodes for heating, with the heater electrodes serving dual purposes as both heating elements and shielding elements to eliminate parasitic capacitance from the vehicle frame.
Solution Approach 2:
The heater electrodes perform multiple functions simultaneously: they provide heating to the mat substrate, act as shield electrodes to prevent parasitic capacitance between the frame and sensor electrodes, and contribute to the overall structural integrity of the mat. This multi-functionality reduces the total number of components needed.
2Adaptability or versatility
If multiple layers of mats are used, then heating and sensing functions are provided, but manufacturing cost and material usage increase
Solution Approach 1:
The patent combines the heater mat, sensing mat, and shielding mat into a single integrated sensor mat. The mat substrate includes both sensor electrodes for capacitance sensing and heater electrodes for heating, with the heater electrodes serving dual purposes as both heating elements and shielding elements to eliminate parasitic capacitance from the vehicle frame.
Solution Approach 2:
The heater electrodes perform multiple functions simultaneously: they provide heating to the mat substrate, act as shield electrodes to prevent parasitic capacitance between the frame and sensor electrodes, and contribute to the overall structural integrity of the mat. This multi-functionality reduces the total number of components needed.
3Reliability
If shielding mat is placed between sensing mat and frame, then parasitic capacitance is prevented, but device complexity increases
Solution Approach 1:
The patent combines the heater mat, sensing mat, and shielding mat into a single integrated sensor mat. The mat substrate includes both sensor electrodes for capacitance sensing and heater electrodes for heating, with the heater electrodes serving dual purposes as both heating elements and shielding elements to eliminate parasitic capacitance from the vehicle frame.
Solution Approach 2:
The heater electrodes perform multiple functions simultaneously: they provide heating to the mat substrate, act as shield electrodes to prevent parasitic capacitance between the frame and sensor electrodes, and contribute to the overall structural integrity of the mat. This multi-functionality reduces the total number of components needed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution allows for effective detection of occupant presence and heating functionality in a single layer, reducing manufacturing complexity and costs while maintaining sensing and heating capabilities without parasitic capacitance issues.
Implementation Method 1
The shield electrode is electrically coupled to a voltage source to create a capacitance between the shield electrode and the sensor electrode, and the sensor electrode is used to detect a change in the capacitance
Implementation Method 2
The shielding mat prevents parasitic capacitance between the frame and the sensing mat
Implementation Method 3
controlling the voltage source to cause a second current to flow through the shield electrode to heat the sensor mat
Data Source
AI summary
According to various implementations, a sensor mat includes a mat substrate, a sensor electrode, and a shield electrode. At least a portion of the sensor and shield electrodes are spaced apart from and parallel to each other on a first surface of the mat substrate. The shield electrode is electrically coupled to a voltage source to create a capacitance between the shield electrode and the sensor electrode, and the sensor electrode is used to detect a change in the capacitance. The shield electrode may also be alternately used for heating the surface of the vehicle part adjacent the mat. For example, the sensor may be disposed adjacent a portion of a steering wheel or a seat assembly and is used for sensing presence of an occupant's hands or body adjacent the steering wheel or seat assembly.