Total-Reflection Rain Sensor Using Mirror for Vehicle Glass
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Solution Overview
Problem
Existing rain sensors often result in unnecessary wiper operation due to inaccurate detection of raindrops, leading to power consumption issues and potential safety hazards, as they fail to differentiate between necessary and unnecessary wiper activation.
Innovation Solution
A total reflection type rain sensor using a mirror with a light emitting unit, adhering portion, and control unit, which emits light to be incident on the vehicle's glass, receives the reflected light, and outputs a control signal to initiate wiper operation only when the detected raindrop amount exceeds a predetermined threshold, utilizing a parabolic mirror module for parallel light reflection and a sawtooth-shaped rotary prism unit for precise light direction adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If existing rain sensors are used to detect raindrops, then wiper operation can be automated, but unnecessary wiper operation occurs due to inaccurate detection
Solution Approach 1:
The glass surface is divided into multiple detection areas, each with its own light emitting unit and light receiving unit. This segmentation allows independent detection in different zones, enabling more precise localization and quantification of raindrops, thereby reducing false detections and unnecessary wiper operations while maintaining automated operation.
2Reliability
If wiper operation is activated frequently to ensure safety, then safety margin is improved, but power consumption increases
Solution Approach 1:
The system changes the parameter of wiper operation from fixed/frequent activation to variable activation based on detected raindrop amount and detection area. The control unit adjusts wiper operation parameters (whether to operate, speed, cycle) according to the severity of rainfall detected, ensuring safety by activating only when necessary while reducing power consumption by avoiding unnecessary operations during light or false detections.
3Measurement precision
If multiple detection areas are implemented to improve detection accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
Each detection area unit (light emitting unit, light receiving unit, and associated processing circuitry) is designed as a universal module that can perform multiple functions: detecting raindrops in its specific area, determining raindrop amount, and contributing to overall control decisions. This modular universal design allows the system to achieve multi-area detection precision while managing complexity through standardized, reusable components rather than entirely separate systems for each function.
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
Minimizes unnecessary wiper operation by accurately detecting raindrops and controlling wiper speed and cycle based on the amount and frequency of raindrops, enhancing power efficiency and reducing potential safety risks.
Implementation Method 1
the light receiving unit receives the light that is emitted from the light emitting unit and then reflected totally from the glass of the vehicle
Implementation Method 2
a light emitting parabolic mirror module allows the light emitted from the light emitting unit to be reflected therefrom in such a manner that (a) wavelengths of the light can be maintained in parallel with each other and (b) the light is incident at an angle that allows the light to be reflected totally from the glass of the vehicle
Data Source
AI summary
The present invention relates to a total reflection type rain sensor using a mirror, which is attached to a glass of a vehicle to detect raindrops falling onto the glass of the vehicle and outputs a signal capable of controlling speed and cycle of a wiper of the vehicle according to the amount and falling frequency of raindrops detected.