Stacked Semiconductor Sensor for Vehicle Windshield Fog Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sensor arrangements for detecting fog on vehicle windshields are not compact enough and lack cost-effective designs for simultaneous temperature and humidity measurement.
Innovation Solution
A compact sensor arrangement featuring stacked semiconductor temperature and humidity sensors, with a thermopile temperature sensor enclosed between a moisture sensor and a microsystem technology cover, allowing for efficient space utilization and protection, and optionally integrated optical elements and an inert gas-filled housing for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate temperature and humidity sensors are used, then measurement accuracy is maintained, but device size and complexity increase
Solution Approach 1:
The patent combines temperature and humidity sensors into a single integrated sensor arrangement. The temperature sensor (thermopile) and humidity sensor are positioned in close proximity within a common housing, allowing both measurements to be taken from the same location without requiring separate sensor assemblies. This merging approach maintains measurement accuracy while significantly reducing overall device size.
Solution Approach 2:
The temperature sensor is nested within the housing structure that also contains the humidity sensor. The thermopile is positioned inside the housing with its sensing area oriented toward the windshield, while the humidity sensor is integrated into the same housing space. This nested arrangement allows both sensors to coexist in a compact configuration without interfering with each other's measurement functions.
2Volume of moving object
If a compact sensor design is implemented, then space utilization improves, but sensor protection and environmental sealing become more difficult
Solution Approach 1:
The patent employs a thin-film membrane structure for the humidity sensor that allows water vapor diffusion while providing environmental protection. The membrane is sufficiently thin to permit humidity measurement but sufficiently robust to protect the internal sensor components from direct environmental exposure. This flexible shell approach enables compact design while maintaining sensor reliability.
Solution Approach 2:
The housing containing both sensors can be filled with an inert gas or evacuated to create a protected environment for the temperature sensor (thermopile). This inert atmosphere prevents thermal interference from the surrounding air while allowing the sensor to accurately measure temperature variations related to fog formation on the windshield.
3Measurement precision
If multiple sensors are integrated in a small space, then fog detection capability improves, but manufacturing complexity increases
Solution Approach 1:
The sensor arrangement is segmented into distinct functional modules: a housing structure, a temperature sensor module (thermopile), and a humidity sensor module. Each module can be manufactured separately using standard techniques and then assembled together. This segmentation reduces manufacturing complexity while maintaining the integrated functionality needed for accurate fog detection.
Solution Approach 2:
The housing structure serves multiple functions simultaneously: it protects the sensors, provides mounting for both temperature and humidity sensors, facilitates air flow to the sensing areas, and can be integrated into the vehicle's existing HVAC system. This multi-functionality reduces the number of separate components needed, simplifying manufacturing while enhancing fog detection capability.
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
Enables simultaneous detection of temperature and humidity in a small space, facilitating effective fog detection and enabling timely countermeasures by vehicle ventilation or air conditioning systems.
Implementation Method 1
a non-contact temperature sensor for measuring the temperature of the inner surface
Implementation Method 2
The temperature sensor is preferably designed as a thermopile
Data Source
Figure 1
AI summary
The invention relates to a sensor arrangement (1) for detection of misting tendency on an inner surface, in particular on the side of a windscreen facing the vehicle interior, comprising a non-contact thermometer (11) for recording the temperature of the inner surface, in particular, the side of the windscreen facing the vehicle interior and a humidity sensor (12) for measuring the humidity of the air which can be particularly compact and simple in construction, whereby the temperature sensor and the humidity sensor are embodied as semiconductor components and the temperature sensor and humidity sensor are arranged in a stack one on the other.