Window Wetness Sensor Optics for Raindrop Position Sensing
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Solution Overview
Problem
Existing sensor devices for detecting wetness on vehicle windows, such as windshields, cannot differentiate the size and position of raindrops due to uneven sensitivity distribution across the detection surface.
Innovation Solution
A sensor apparatus with a radiation emitter and receiver, featuring an optical guide element with inclined lens contours on both the inlet and outlet sides, allowing for even radiation distribution and focusing onto multiple sensorially active regions, enabling precise detection of raindrop size and position by varying signal intensity across the detection surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional sensor device with uniform sensitivity distribution is used, then the device structure is simple, but the ability to differentiate raindrop size and position is lost
Solution Approach 1:
The lens arrangement is segmented into multiple lens contours (at least two) on both the inlet and outlet sides of the optical guide element. Each lens contour corresponds to a specific sensorially active region, creating distinct detection zones that enable spatial differentiation of raindrop characteristics while maintaining a relatively simple integrated structure.
Solution Approach 2:
Different regions of the detection surface are assigned different sensitivities through the lens contour arrangement. The lens contours are configured to direct radiation from specific areas onto corresponding sensorially active regions, creating local quality variations that enable precise raindrop size and position differentiation without requiring a completely complex device architecture.
2Measurement precision
If sensitivity is distributed unevenly over the detection surface, then device structure is simple, but position and size of water drops cannot be differentiated
Solution Approach 1:
The detection surface is segmented into multiple zones through the lens contour configuration, with each zone corresponding to a specific sensorially active region. This segmentation enables differentiated sensitivity across the detection surface, allowing precise determination of water drop position and size while maintaining ease of operation through the integrated lens-guide element structure.
Solution Approach 2:
The lens contours act as intermediaries between different regions of the detection surface and the sensorially active regions. They mediate the radiation paths to create the desired non-uniform sensitivity distribution, enabling water drop differentiation without requiring complex post-processing or operational adjustments.
3Measurement precision
If multiple lens contours are arranged side by side with inclined surfaces, then radiation distribution and focusing precision is improved, but manufacturing complexity increases
Solution Approach 1:
Multiple lens contours are merged into a single integrated optical guide element structure. The lens contours are arranged side by side with inclined surfaces that are manufactured as part of the monolithic guide element, reducing the number of separate components and simplifying assembly while maintaining high radiation focusing precision through the integrated design.
Solution Approach 2:
The lens contours utilize curved surfaces with specific inclinations to focus radiation precisely onto the sensorially active regions. The curved geometry of the lens contours enables accurate radiation control while being manufacturable as integrated features of the optical guide element, balancing manufacturing precision requirements with optical performance.
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
This solution allows for accurate determination of raindrop position and size, enhancing the sensitivity and statistical plausibility of measurements, thereby improving the detection of wetness on vehicle windows.
Implementation Method 1
an optical sensor apparatus may be used, for example, in which for example a radiation signal, particularly an infrared signal, is coupled into the windscreen, and then coupled out again after the radiation has traversed a track in the windscreen. It is possible to determine the percentage of total internal reflections in the windscreen
Implementation Method 2
the lens arrangement of the radiation inlet side has at least two lens contours, that the inlet surfaces of the lens contours of the radiation inlet side, through which the radiation is able to enter the guide element, are inclined towards each other
Data Source
AI summary
A sensor apparatus for detecting the wetness of window, with a radiation emitter and a radiation receiver, with an optical guide element which can be coupled to the inner side of the window, the radiation inlet side and the radiation outlet side of the guide element are each embodied as a lens arrangement, and a lens arrangement is embodied by lens contours arranged side by side. The lens arrangement on the radiation inlet side has at least two lens contours. The inlet surfaces of the lens contours on the radiation inlet side, through which the radiation is able to enter the guide element, are inclined towards each other. The lens arrangement on the radiation outlet side has at least two lens contours. The outlet surfaces of the lens contours on the radiation outlet side, through which the radiation can exit the guide element, are inclined towards each other.