Door Handle Capacitive Sensor Shield Layout for Lower Parasitic Capacitance
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Solution Overview
Problem
Capacitive sensors in vehicle door handles face interference from shielding elements, which disrupt detection and require significant technical effort to minimize.
Innovation Solution
A sensor device with a shielding arrangement on a multilayer printed circuit board, where distances between shielding elements and the sensor element are varied to maximize spacing and reduce parasitic capacitance, allowing flexible adaptation to electrical arrangements and optimizing capacitive detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If shielding elements are used to define a detection area on the door handle, then the detection area can be defined and controlled, but the shielding elements have a disruptive effect on the capacitive detection due to parasitic capacitance
Solution Approach 1:
The patent applies local quality by varying the distance between shielding elements and the sensor element at different locations. Specifically, the distance is increased in areas where parasitic capacitance causes disruption, while maintaining smaller distances in areas where shielding is more critical for defining the detection area. This localized adjustment of spacing optimizes the balance between shielding effectiveness and parasitic capacitance reduction.
Solution Approach 2:
The patent changes the geometric parameter of distance between the shielding elements and the sensor element. By varying this distance parameter, the patent reduces parasitic capacitance influence while maintaining effective shielding. The distance is specifically increased to at least 0.5mm in certain areas to reduce capacitive coupling and improve detection accuracy.
2Measurement precision
If the distance between shielding elements and sensor element is increased to reduce parasitic capacitance, then detection accuracy improves, but the shielding effectiveness may be reduced
Solution Approach 1:
The patent implements local quality by applying different distance configurations in different spatial regions. In regions where shielding is paramount, smaller distances are maintained, while in regions where parasitic capacitance is the primary concern, larger distances are used. This localized differentiation allows the system to optimize both shielding effectiveness and detection accuracy in their respective zones.
Solution Approach 2:
The shielding arrangement is segmented into multiple shielding elements rather than using a single continuous shield. This segmentation allows independent optimization of each shielding element's distance from the sensor element, enabling the system to reduce parasitic capacitance in critical areas while maintaining shielding effectiveness in other areas through the collective action of multiple segmented shields.
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 effectively reduces the disruptive influence of parasitic capacitance, enhancing the accuracy and reliability of capacitive detection in vehicle door handles and other applications.
Implementation Method 1
a sensor element (40) which is designed to be electrically conductive on the printed circuit board arrangement (20) in order to capacitively detect the activation action
Implementation Method 2
distances D1, D2, D3 correlating with an influence on the capacitive detection, in particular reducing parasitic capacitance
Data Source
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AI summary
The invention relates to a sensor device (10) for capacitive detection of an activation action in a vehicle (1), in particular for a door handle (2) of the vehicle (1), comprising: - a printed circuit board arrangement (20) for providing an electrical arrangement (70) of the sensor device (10), in particular for door handle electronics, - a sensor element (40) which is electrically conductive on the printed circuit board arrangement (20) to provide capacitive detection of the activation action, - a shielding arrangement (60) which is electrically conductive on the printed circuit board arrangement (20) at least two distances (D1, D2, D3) from the sensor element (40) to provide shielding at the distances (D1, D2, D3) for the sensor element (40), wherein the distances (D1, D2, D3) correlate with an influence on the capacitive detection, wherein the distances (D1, D2,D3) in particular adapted to the electrical arrangement (70), preferably are maximized to reduce the influence limited by the electrical arrangement (70).