Capacitive Vehicle Approach Sensor Sealing Without Sensitivity Loss
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Solution Overview
Problem
Capacitive proximity sensors in approach detection devices are sensitive to environmental conditions and require specialized components, leading to increased costs and reduced detection sensitivity due to the use of insulating materials for protection, and existing sealants can cause detachment issues from vehicle body components.
Innovation Solution
A modular approach detection device with a capacitive proximity sensor system featuring a sensor carrier and carrier frame design that aligns the active capacitive surface for optimal detection, using a compressible sealant with through-openings to reduce expansion pressure and prevent interference with the sensor's detection capability, and an adhesive coating for secure attachment without additional fastening means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacitive sensor arrangement is protected by filling the space with electrically insulating material, then protection against environmental influences is improved, but detection sensitivity deteriorates due to capacitance influence from the dielectric material
Solution Approach 1:
The patent extracts the insulating material only from the detection area where the capacitive sensor's active surface is located, while maintaining protection in other areas. The sensor carrier has a recess that exposes the active surface to the environment without insulating material interference, while the sensor housing still provides overall protection against environmental influences through sealing in non-detection areas.
Solution Approach 2:
The patent applies different sealing qualities to different areas: the detection area remains open and free of insulating material to maintain sensor sensitivity, while other areas of the sensor housing are sealed to protect against environmental influences. This local differentiation allows simultaneous achievement of protection and sensitivity.
2Ease of manufacture
If compressible sealant is used for attachment to body panel, then ease of installation is improved, but detachment risk increases due to expansion pressure promoting device detachment
Solution Approach 1:
The patent uses a compressible sealant with through-openings (porous structure) that reduces expansion pressure while maintaining sealing functionality. The through-openings allow the sealant to compress without building excessive pressure that would cause detachment, while still providing adequate sealing and adhesion properties for easy installation.
3Measurement precision
If specialized components are manufactured for sensor device, then detection performance is improved, but manufacturing cost increases due to inability to use universal components
Solution Approach 1:
The patent designs the sensor carrier and sensor housing as universal components that can be used across different application scenarios. The modular sensor carrier with standardized mounting features and the adaptable sensor housing allow the same components to serve multiple functions and applications, reducing the need for specialized custom-manufactured parts while maintaining detection performance.
Solution Approach 2:
The patent segments the sensor system into modular components (sensor carrier, sensor housing, sealant) that can be independently manufactured and assembled. This segmentation allows for standardized production of individual components that can be universally applied, reducing manufacturing costs while maintaining the required detection performance through proper component design and assembly.
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 enhances the detection sensitivity and reduces the risk of detachment while allowing for universal application and cost-effective production, maintaining protection against environmental influences and simplifying attachment to various vehicle body shapes.
Implementation Method 1
the change in the capacitance of an electrode arrangement is measured, with the capacitance being dependent on the distance between a part of the user's body and the electrode arrangement
Implementation Method 2
The space between the sensor assembly and the housing wall is filled with an electrically insulating material to prevent the ingress of moisture or other foreign matter that could affect the capacitance of the sensor system
Implementation Method 3
an adhesive coating is arranged at least in sections on the surface of the fastening section of the carrier frame facing the body part of the motor vehicle, with which the proximity detection device can be fastened to the body part
Data Source
AI summary
The present invention relates to an approach detection device for motor vehicles. Known approach detection devices have the disadvantage that said devices are optimized specifically for certain detection scenarios, i.e. different devices must be used for each detection scenario. The approach detection device according to the invention comprises a sensor carrier (2) having an intake space, sensor electronics (3) arranged in the intake space of the sensor carrier (2), which sensor electronics have at least one capacitive approach sensor (4) that is coupled to an evaluation circuit, and a carrier frame (6) which comprises a fastening section (8) by which the approach detection device (1) can be mounted to a vehicle body part of the motor vehicle as well as a detection opening (9). The sensor carrier (2) is mounted to the carrier frame (2) in such a manner that the capacitive approach sensor (4) is oriented towards the detection opening and released from said detection opening, and that in the region of the detection opening (9) an intake space (10) defined by the detection opening (9) and the sensor carrier is formed. The device further comprises a sealing means (11) which is arranged in the intake space (10) on the sensor carrier at least in the region of the active capacitive surface (2) of the capacitive approach sensor (5).