Capacitive Surface Force Sensor for Attached Object Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current vehicle sensors are ineffective in detecting objects attached to a vehicle's surface using magnets, tape, or adhesive, and fail to differentiate between contact and attachment, often triggering alerts for non-attached objects due to proximity sensitivity.
Innovation Solution
A capacitive structure comprising a three-layer stack or single-layer thin film sensor is applied to the vehicle's outer surface, utilizing a transparent conductor, dielectric layer, and another conductive layer to measure capacitance changes caused by compressive, tensile, or shear forces, providing a clear alert only when an object is attached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If proximity-sensitive sensors are used to detect objects near the vehicle surface, then detection sensitivity is improved, but false alarms increase due to inability to differentiate between contact and attachment
Solution Approach 1:
The patent changes the measurement parameter from simple proximity detection to capacitance measurement. The capacitive structure measures electrical capacitance between the vehicle surface and the sensor, which changes differently for contact versus attachment scenarios, enabling reliable differentiation while maintaining high detection sensitivity
Solution Approach 2:
The patent replaces mechanical contact-based detection with electrical capacitance-based detection. By using a capacitive structure with conductive layers and dielectric materials, the system detects changes in electrical field rather than mechanical force, allowing it to distinguish between temporary contact and permanent attachment based on capacitance characteristics
2Measurement precision
If multi-layer capacitive structure is applied to the vehicle surface, then measurement precision for differentiating contact and attachment is improved, but device complexity increases
Solution Approach 1:
The patent uses thin film structures for the capacitive sensor layers, including flexible conductive layers and dielectric films. This approach achieves the required measurement precision while keeping the overall device structure simple and suitable for application on vehicle surfaces
Solution Approach 2:
The patent employs composite material structures combining different conductive materials and dielectric materials in a layered capacitive structure. This composite approach enables precise differentiation between contact and attachment through tailored electrical properties while maintaining a manageable device complexity through systematic material selection
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 differentiates between contact and attachment, providing continuous alerts for attached objects while minimizing false alarms from non-touching objects, enhancing safety and monitoring capabilities.
Implementation Method 1
A capacitive structure (100) for a vehicle (10) having an outer surface (12) is disclosed. The capacitive structure (100) includes a first conductive layer (102), a dielectric layer (104), and a second conductive layer (106). A capacitance meter (410) measures capacitance of the capacitive structure (100) as a force is applied, and sometimes released, to a second side (106A2) of the second conductive layer (106A).
Data Source
AI summary
A sensor configured to sense when a force is applied to a surface includes a capacitive structure having a first conductive layer, a dielectric layer, and a second conductive layer. The dielectric layer is overlain on the first conductive layer and the second conductive layer is overlain on the dielectric layer. A glass superstrate has a first side and a second side, with the first side overlain on the second conductive layer. The force is applied to the second side of the glass superstrate. The force results from an object attached to the second side of the glass superstrate. The force causes capacitance changes between the first and second conductive layers. The force can be compressive or tensile, depending on whether the object is attached by magnet or adhesive.