Interleaved Electrode Proximity Sensor for Automotive Switches
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Solution Overview
Problem
Existing proximity switches in automotive applications face challenges in distinguishing between intentional switch activation and exploratory motions, particularly in distracted driving scenarios, leading to potential premature activation of switches.
Innovation Solution
A proximity sensor assembly with interleaved electrode configurations, including first and second electrodes interdigitated with third and fourth electrodes, generates overlapping activation fields to differentiate between intended activation and exploratory motions by analyzing signal changes and thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional capacitive switches are used with separate interface areas, then switch activation detection is achieved, but premature activation occurs during exploratory motions
Solution Approach 1:
The patent merges the electrodes of adjacent capacitive switches by interleaving them into a shared electrode structure. First and second electrodes belong to a first capacitive switch, while third and fourth electrodes belong to a second capacitive switch, with all four electrodes interleaved together. This merging allows the system to detect exploration motions that affect multiple electrodes simultaneously, enabling discrimination between exploration and intentional activation.
2Ease of operation
If multiple capacitive switches are placed in close proximity, then user accessibility is improved, but discrimination between exploration and activation becomes difficult
Solution Approach 1:
Adjacent capacitive switches share interleaved electrodes, reducing the total number of separate electrode structures while maintaining multiple switch functions. The first capacitive switch uses first and second electrodes, and the second capacitive switch uses third and fourth electrodes, with all electrodes interleaved in a shared interface area.
Solution Approach 2:
The patent transitions from separate two-dimensional electrode interfaces to a three-dimensional interleaved structure where electrodes from multiple switches are stacked and interlaced vertically and horizontally, enabling complex signal patterns that encode both position and intent information.
3Measurement precision
If electrodes are interdigitated within separate interface areas, then individual switch detection is achieved, but enhanced proximity detection is limited
Solution Approach 1:
The patent combines multiple electrode pairs into a single interleaved structure where first electrodes, second electrodes, third electrodes, and fourth electrodes are all interlaced together in the same physical space, enabling the system to detect capacitive changes from multiple switch perspectives simultaneously.
Solution Approach 2:
The interleaved electrode structure serves multiple functions: it detects individual switch activation, identifies exploration motions across multiple switches, provides enhanced proximity detection, and enables discrimination between intentional and unintentional contact, all within a single unified structure.
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 unintended switch activations by allowing users to explore switch interfaces without triggering events, enhancing user safety and interface responsiveness in automotive environments.
Implementation Method 1
Capacitive switches are typically configured to detect user actuation of the switch based on comparison of the sense activation field to a threshold
Implementation Method 2
The electrode fingers are typically interdigitated, that is, dispersed one between the other and are charged to form a capacitive coupling
Data Source
AI summary
A proximity switch assembly and method for detecting activation of a proximity switch assembly is provided. The assembly includes a plurality of proximity switches each having a proximity sensor providing a sense activation field. A first proximity sensor generates a first activation field and comprises first and second electrodes having first fingers interdigitated with second fingers. A second proximity sensor generates a second activation field and comprises third and fourth electrode fingers having third fingers interdigitated with fourth fingers. The first and second electrodes are interleaved with the third and fourth electrodes.