Flexible Sensor Film for Seamless Capacitive Vehicle Surfaces
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Solution Overview
Problem
Existing decorative and functional surfaces in vehicles, such as dashboards and seats, require numerous mechanical controls and switches that disrupt the design and are difficult to integrate with flexible and stretchable sensor systems, making intuitive operation challenging due to the complexity and inflexibility of current touch sensor technologies.
Innovation Solution
A flexible and stretchable decorative film with integrated conductive polymeric layers acting as capacitor plates, allowing for capacitive sensing without visible disruption to the surface, enabling intuitive operation by lightly touching the film and maintaining functionality under stretching conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanical controls and switches are integrated into vehicle surfaces, then operational functions are provided, but the design is disrupted and the surface appearance is compromised
Solution Approach 1:
The patent extracts the control function from physical mechanical buttons and switches, removing visible mechanical components from the surface. Instead, capacitive touch sensors are integrated directly into the decorative film layers, allowing control functions to be provided through invisible or minimally visible sensor areas that maintain the continuous surface appearance.
Solution Approach 2:
The patent replaces the mechanical control system (physical buttons, switches, and levers) with a capacitive touch sensing system. The mechanical interaction is substituted by electrical field detection through capacitive coupling, where touch input is detected through changes in capacitance rather than mechanical actuation, eliminating the need for visible mechanical components.
2Difficulty of detecting and measuring
If traditional touch sensors are used in flexible films, then sensing function is provided, but the film cannot be stretched or deformed
Solution Approach 1:
The patent uses flexible thin film structures for the sensor layers, where the sensor elements are integrated into multiple flexible layers that can be stretched and deformed. The capacitive sensor structure consists of conductive layers separated by dielectric film layers, all of which maintain their functional properties under deformation, enabling the sensor to work on flexible and stretchable substrates.
Solution Approach 2:
The patent employs composite material structures combining conductive layers, dielectric layers, and flexible substrate materials. The sensor system is built as a multi-layer composite where each layer contributes specific properties: conductive layers for charge storage, dielectric layers for insulation and mechanical flexibility, and substrate materials for stretchability. This composite structure maintains sensing functionality while enabling flexibility and deformation.
3Adaptability or versatility
If sensor layers are integrated into decorative films, then functional surfaces are created, but the manufacturing process becomes complex
Solution Approach 1:
The patent merges the sensor layer integration with the existing decorative film manufacturing process. The capacitive sensor layers are combined with the decorative film layers during the same lamination and heating process, rather than requiring separate sensor fabrication and assembly steps. This integration approach allows sensor elements to be incorporated into the film structure in a single manufacturing flow.
Solution Approach 2:
The patent creates a multi-functional film structure where the same layered construction serves both decorative and sensing functions. The conductive and dielectric layers that form the capacitive sensor are integrated within the decorative film stack, allowing the film to simultaneously provide aesthetic appearance and touch sensing capability without requiring separate specialized manufacturing processes for each function.
4Measurement precision
If capacitive sensor arrays are implemented on surfaces, then multiple touch points can be detected, but the surface requires rigid structure
Solution Approach 1:
The patent implements capacitive sensor arrays using flexible thin film layers instead of rigid substrates. The sensor array consists of conductive patterns on flexible film layers that can be stretched and deformed while maintaining electrical connectivity and sensing capability. The flexible film structure allows the sensor array to conform to curved or deformable surfaces while preserving touch detection precision.
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 provides a seamless integration of sensor functions within decorative surfaces, allowing for intuitive control of vehicle functions without visible switches, maintaining flexibility and appearance, and enabling easy application to vehicle components without distortion.
Implementation Method 1
Capacitive touch sensors are based on a capacitive coupling effect. By appropriately coating a substrate, a large number of independent touch sensors can be implemented, allowing for the simultaneous detection of multiple touch points.
Implementation Method 2
Resistive and capacitive systems are commonly used in such touch sensors. Resistive systems typically consist of two layers of electrically conductive or semiconducting material (often ITO = indium tin oxide), with the two layers separated by a thin layer of air or microdots. Applying pressure to a specific point causes contact between the two layers, altering an electrical signal transmitted through the lower layer.
Data Source
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AI summary
Flexible sheet made of polymer material, preferably a plastics-material sheet provided with a grain structure or embossing, which has functional surface-area regions designed in the form of a switching, sensor or operating element such that the sheet is of multi-layered design at least in the region of the functional surface-area regions, wherein at least one layer made of conductive polymer material is arranged in the functional surface-area regions, wherein the layer made of conductive material is spaced apart, on the rear side, from the visible surface of the sheet and is connected to an electronic control and regulating device, which detects changes in electrical properties of the sheet in the functional surface-area regions and converts these into actuating, switching or control signals.