Self-standing Sandwich Structure for Automotive Capacitive Sensors
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Solution Overview
Problem
Conventional capacitive sensors and heating systems for automotive applications, particularly in steering wheels, face challenges in achieving a reliable multizone design with high operational robustness and simplified integration, due to the complex geometry of steering wheels.
Innovation Solution
A self-standing sandwich structure comprising an upper protective layer, a lower protective layer, an adhesive layer, and an electrically conductive layer, which can be easily manufactured and attached to stretchable materials, enabling close-to-surface integration and combining capacitive sensing and heating with low installation effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional capacitive sensors and heating systems are used for automotive steering wheels, then basic sensing and heating functions are achieved, but integration complexity increases and operational robustness decreases due to complex steering wheel geometry
Solution Approach 1:
The steering wheel surface is divided into multiple independent sensing zones, each with its own capacitive sensor elements. This segmentation allows each zone to operate independently, improving reliability while simplifying the overall integration process by breaking down the complex geometry into manageable segments
Solution Approach 2:
The capacitive sensor structure is designed to serve multiple functions: touch detection, heating element integration, and geometric adaptation to complex steering wheel surfaces. This multi-functionality reduces the number of separate components needed, thereby reducing integration complexity while maintaining operational robustness
2Adaptability or versatility
If capacitive sensors are integrated into steering wheels with complex geometry, then hands-on detection capability is achieved, but manufacturing and installation difficulty increases
Solution Approach 1:
The capacitive sensor utilizes flexible thin film structures that can conform to the complex geometry of steering wheels. This flexibility enables easy adaptation to different steering wheel shapes and sizes, achieving multizone functionality while simplifying manufacturing and installation processes
Solution Approach 2:
The sensor design transitions from planar two-dimensional patterns to three-dimensional conformal structures that wrap around the steering wheel geometry. This dimensional adaptation allows the sensor to maintain functionality across complex surfaces while enabling standardized manufacturing processes
3Ease of manufacture
If capacitive sensor members and heater members are combined in a single structure, then integration stress is reduced, but structural complexity increases
Solution Approach 1:
The capacitive sensor elements and heater elements are merged into a single integrated structure where both functions share common substrates, conductive layers, and protective coatings. This merging reduces the number of separate components and assembly steps, thereby reducing integration stress while the modular design keeps structural complexity manageable
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 self-standing sandwich structure facilitates a multizone functionality for detecting hands and their locations on a steering wheel, offering improved sensitivity and energy-efficient heating with reduced integration stress, enhancing the reliability of capacitive sensor and heater systems.
Implementation Method 1
A capacitive sensor or capacitive sensing device, called by some electric field sensor or proximity sensor, designates a sensor, which generates a signal responsive to the influence of what is being sensed (a person, a part of a person's body, a pet, an object, etc.) upon an electric field
Implementation Method 2
at least one antenna electrode, to which is applied an oscillating electric signal and which thereupon emits an electric field into a region of space proximate to the antenna electrode
Implementation Method 3
at least one electrically conductive layer... comprising electrically resistive material for generating electric heat during operation
Data Source
AI summary
A self-standing sandwich structure includes at least one capacitive sensor member and/or at least one heater member for automotive vehicle application. The self-standing sandwich structure includes an upper protective layer that is attached, for manufacturing and storage purposes, to a carrier film member of sufficiently low surface energy for enabling separating the carrier film member and the upper protective layer in a non-destructive manner, a lower protective layer, a bottom adhesive layer that is attached to the lower protective layer, and at least an upper electrically conductive layer arranged between the upper protective layer and the lower protective layer.