Dual Mode Optical Rain Sensor Eliminates Prisms
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current rain sensors for vehicles require additional components like prisms and collimating lenses, increasing cost and space, and are ineffective in detecting continuous water films or coatings on windshields.
Innovation Solution
A device using a radiation source, internal reflection sensors, and scattered reflection sensors to detect rain or substances on windshields, with a processor determining conditions based on reflected radiation magnitude and frequency, allowing for efficient control of windshield wipers and fluid application without the need for collimating lenses or prisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prisms and collimating lenses are used to guide light for total internal reflection, then the rain sensor can detect raindrops effectively, but the device complexity and cost increase due to additional components and space requirements
Solution Approach 1:
The patent removes the collimating lens and prism components from the optical path, extracting only the essential elements needed for rain detection. The simplified design uses direct light emission from the LED toward the windshield without requiring these additional optical guiding components, thereby reducing device complexity while maintaining detection functionality.
Solution Approach 2:
The windshield itself serves as the optical element that directs light to the sensor. The natural reflection and refraction properties of the windshield glass replace the need for separately installed prisms and collimating lenses, allowing the system to utilize the existing structure for its optical function.
2Measurement precision
If traditional internal reflection sensors are used, then individual raindrops can be detected, but continuous water films or coatings on the windshield cannot be detected
Solution Approach 1:
The patent enhances the sensor's capability to detect multiple types of moisture conditions - both discrete raindrops and continuous water films or coatings. By positioning the sensor to receive light reflected from the windshield at a specific angle and using signal processing to analyze reflection characteristics, the system can distinguish between different moisture conditions and respond appropriately to each.
Solution Approach 2:
The patent replaces complex mechanical optical systems with electronic signal processing to achieve versatile detection. Instead of using multiple physical sensors or complex optical arrangements to detect different moisture types, the system uses a single optical sensor combined with signal analysis to identify various moisture conditions based on their distinct reflection patterns.
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 cost-effective, space-efficient, and robust rain sensing system capable of detecting various precipitation levels and substances on windshields, enhancing the accuracy and reliability of windshield wiper operation.
Implementation Method 1
a first portion of the radiation reflects from the windshield
Implementation Method 2
a second portion of the radiation passes through the windshield
Implementation Method 3
at least some of the first portion of the radiation that reflects from the detection area on the windshield is incident on the internal reflection sensor
Implementation Method 4
at least some of the second portion of the radiation reflecting from rain near the windshield or a substance on the windshield may be incident on the scattered reflection sensor
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
An illustrative example embodiment of a device (30) for detecting rain or a substance on a windshield (22) includes at least one radiation source (32), an internal reflection sensor (42) situated to detect at least some of a first portion of the radiation (32) that reflects from the windshield (22). The internal reflection sensor (42) provides a first output that has a characteristic that differs based on whether at least one raindrop (60) is on the windshield (22). A scattered reflection sensor (44) is situated to detect at least some of a second portion of the radiation (32) reflecting from rain near the windshield (22) or a substance on the windshield (22). The scattered reflection sensor (44) provides a second output indicative of an amount of radiation (32) incident on the scattered reflection sensor (44). A processor is configured to determine a condition of the windshield (22) based on the first output and the second output.