Segmented Sensor Electrode Layout Inside a Vehicle NFC Coil
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Solution Overview
Problem
The existing sensor devices for motor vehicle door handles, which combine capacitive sensors and near-field transmission devices, face challenges in minimizing installation space while maintaining sensitivity, as larger sensor elements are required for optimal performance, leading to space-intensive designs that interfere with each other's functionality.
Innovation Solution
The sensor device integrates a capacitive sensor electrode within the near-field transmission coil, with the electrode arranged in sections that connect serially and are positioned within the coil's area, minimizing space usage and reducing counter-inductance, allowing for a compact design without significant interference with the near-field transmission coil's field strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the sensor electrode is placed within the near-field transmission coil to reduce space requirements, then the installation space is minimized, but the field strength of the near-field transmission coil is reduced due to counter-inductance
Solution Approach 1:
The sensor electrode is divided into multiple sensor sections that are arranged in series within the near-field transmission coil. This segmentation allows the electrode to be positioned within the coil's area to minimize space while reducing the counter-inductance effect on the coil's field strength, as the series arrangement optimizes the electromagnetic interaction between the coil and electrode segments.
2Measurement precision
If the sensor elements are arranged side by side to maintain sensitivity, then the sensitivity is improved, but the device becomes space-intensive
Solution Approach 1:
The sensor electrode is nested within the area of the near-field transmission coil, with the electrode arranged in sections inside the coil's boundary. This nesting arrangement allows both the capacitive sensor and inductive near-field transmission device to share the same spatial area, minimizing the overall installation space while maintaining the sensitivity of both components through optimized positioning.
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 configuration enables a highly space-efficient sensor device that maintains the sensitivity of both components, reducing counter-induction and simplifying user interaction by integrating the sensor areas within the near-field transmission coil, thus minimizing the necessary installation space without compromising performance.
Implementation Method 1
The capacitive sensor includes a sensor electrode and a control and evaluation circuit. When approaching a hand of the operator, for example, the capacity of the sensor electrode is changed, whereby this change in capacity is recorded and evaluated
Implementation Method 2
A near-field transmission facility can therefore be provided for identification and legitimation testing of the user, which enables communication between the vehicle and, for example, the mobile phone in the close range. Such a near-field transmission facility can, for example, are based on the International Near Field Communication (NFC) transmission standard.
Data Source
Figure 1~2
AI summary
The invention relates to a sensor device (1) for a motor vehicle, comprising a substrate (2) on which a sensor electrode (3) of at least one capacitive sensor and a near-field transmission coil (4) with at least one turn of at least one inductive near-field transmission device are arranged in a planar manner, wherein the sensor electrode (3) is at least partially surrounded by the near-field transmission coil (4), wherein the sensor electrode (3) has a plurality of straight-running sensor sections (5) connected in series and at least one connecting section (6), wherein each connecting section (6) connects two successive sensor sections (5), so that each first sensor section (5) transitions into a second sensor section (5) following in series by means of a connecting section (6).