Capacitive Transmitter Electrode With Dual Connection Points
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing capacitive sensing devices in automotive vehicles face issues with detecting failures in the connection between the transmitter electrode and the electronic sensing unit, leading to erroneous object detection and inadequate deployment of secondary restraint systems due to potential short-circuits.
Innovation Solution
The transmitter electrode is designed with a conductive sheet material featuring cut-outs and incisions within its sensing area, reducing capacitance and allowing for a longer conductive path, along with a diode at the connecting point to check the electrical integrity, ensuring accurate object detection and preventing short-circuit errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the transmitter electrode uses a simple conductive sheet material with one connecting point, then the electrode structure is simple and easy to manufacture, but the connection failure cannot be detected leading to erroneous object detection
Solution Approach 1:
The single connecting point is segmented into two separate connecting points (first connecting point and second connecting point) that are electrically separated by the incision. This segmentation allows independent connection to the electronic sensing unit, enabling detection of connection failures while maintaining manufacturing simplicity through the basic conductive sheet structure.
Solution Approach 2:
The electronic sensing unit acts as an intermediary that receives signals from both connecting points independently. By monitoring the electrical connection status at both points, the system can detect connection failures between the transmitter electrode and the electronic sensing unit, preventing erroneous object detection while keeping the electrode structure simple.
2Area of stationary object
If the transmitter electrode has large surface area to maximize sensing coverage, then the sensing coverage is improved, but the capacitance increases requiring more complex electronics
Solution Approach 1:
The electrode surface is segmented by introducing incisions that divide the continuous conductive sheet into regions separated by non-conductive paths. This segmentation reduces the effective capacitance between the transmitter electrode and vehicle floor while preserving the overall sensing coverage area, thereby simplifying the electronics requirements.
Solution Approach 2:
Different regions of the conductive sheet have different electrical properties due to the incisions. The areas between incisions maintain conductive properties for sensing, while the incision regions create electrical isolation that reduces overall capacitance. This local differentiation allows large sensing coverage with reduced capacitance, simplifying electronic requirements.
3Device complexity
If the transmitter electrode uses cut-outs to reduce capacitance, then the electronics can be lighter and smaller, but the electrode surface area and sensing coverage are reduced
Solution Approach 1:
Instead of removing material (cut-outs), the patent uses incisions (non-conductive paths) to segment the conductive sheet. This segmentation reduces the effective capacitance by creating electrical isolation regions while preserving the physical continuity and surface area of the electrode for sensing purposes, thus maintaining sensing coverage while reducing capacitance.
Solution Approach 2:
The incisions create local non-conductive regions within the conductive sheet that reduce overall capacitance without removing electrode material from the sensing area. This local modification allows the electrode to maintain full surface area for sensing while having reduced capacitance characteristics, enabling lighter and smaller electronics.
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
This design enhances the reliability of seat occupancy detection, reduces the risk of erroneous deployment, and allows for lighter, smaller, and less expensive electronics with reduced material consumption, while maintaining sensitivity and coverage.
Implementation Method 1
One approach for gathering relevant parameters of a seat occupancy is based on the detection of the capacitive coupling of a body to one or several electrodes arranged in the seat
Implementation Method 2
the capacitor formed by the transmitter electrode and the vehicle floor can be considered as a plate capacitor so that the capacitance of the formed capacitor is substantially proportional to the area of the transmitter electrode
Data Source
AI summary
A transmitter electrode (10) for a capacitive sensing device comprises a conductive sheet material (12), said conductive sheet material comprising a first connecting point (16) for connecting the electrode to an electronic sensing unit. According to the invention the conductive sheet material comprises at least one second connecting point for connecting the electrode to an electronic sensing unit, said second connecting point (16′) being arranged at a certain distance from said first connecting point so that said conductive sheet material forms a conductive path between said first and second connecting point. The first and second connecting point (16, 16′), which in use are both connected to the electronic sensing unit, enable to check the integrity of the transmitter electrode and the connection lines used to connect the transmitter electrode to the electronic sensing unit.