Transparent Capacitive Rain Sensor for Vehicle Windshield
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Solution Overview
Problem
Existing vehicle rain sensors are complex, expensive, and prone to accuracy degradation due to contamination, with optical sensors disturbing driver visibility and wire-based sensors obstructing the view, while mist on windshields disrupts driving by requiring manual air conditioner or hot-wire operation.
Innovation Solution
A vehicle sensor system featuring transparent, single-layered sensing electrodes on vehicle glass, capable of measuring raindrops and mist through capacitance variation, with a control unit that automatically operates the wiper or hot-wire for precise moisture management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical rain sensor is used with light emitting and receiving units, then rain detection capability is improved, but device complexity and production cost increase
Solution Approach 1:
The patent extracts the rain sensing function from complex optical systems and implements it using a simple capacitance-based sensor. The sensor includes a sensing electrode that directly measures capacitance changes caused by raindrops, eliminating the need for light emitting units, light receiving units, and associated optical components. This extraction of the core sensing function resolves the technical contradiction by maintaining rain detection capability while dramatically reducing structural complexity.
Solution Approach 2:
The patent replaces the optical system (mechanical/light-based) with an electrical field-based capacitance sensing system. Instead of using light emission and detection mechanisms, the invention uses a sensing electrode that detects raindrops through capacitance variation. This substitution of the underlying physical principle resolves the contradiction by achieving the same measurement function with a simpler, more cost-effective electrical system.
2Measurement precision
If optical rain sensor is installed on front glass, then rain detection is improved, but driver visibility is disturbed
Solution Approach 1:
The patent applies the principle of transparency by designing the sensing electrode to be visually imperceptible. The electrode is formed with a transparent conductive material or in a pattern that allows light to pass through, making it invisible to the driver while maintaining its electrical sensing function. This resolves the contradiction by enabling accurate rain detection on the front glass without compromising driver visibility.
3Measurement precision
If wire electrode is disposed inside windshield glass, then rain sensing is achieved, but driver sight is obstructed
Solution Approach 1:
The patent makes the sensing electrode transparent or visually imperceptible by using transparent conductive materials or designing the electrode pattern to be invisible. This allows the wire electrode to be disposed inside the windshield glass for rain sensing while maintaining driver sight, as the electrode does not obstruct the visual field.
4Productivity
If mist accumulates on vehicle windshield glass, then driving continues, but driver concentration is disturbed due to manual operation requirement
Solution Approach 1:
The patent implements automatic mist detection and removal control through feedback mechanisms. The capacitance sensor continuously monitors the windshield surface for mist accumulation, and when mist is detected, the system automatically activates the air conditioner or hot-wire to remove the mist. This feedback-based automatic control resolves the contradiction by maintaining driving continuity while eliminating the need for manual driver operation, thus preserving driver concentration.
Solution Approach 2:
The patent enables the windshield mist removal system to operate autonomously without driver intervention. The capacitance sensor automatically detects mist conditions and triggers the appropriate removal mechanism (air conditioner or hot-wire), allowing the system to service itself and maintain clear visibility without requiring the driver to manually operate controls. This self-service capability resolves the contradiction by maintaining driving continuity while keeping the driver focused on the road.
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 system provides accurate, non-intrusive detection and removal of raindrops and mist, enhancing driver convenience by maintaining visibility and automating windshield maintenance, while being cost-effective and easy to integrate.
Implementation Method 1
the sensing electrode may sense a raindrop provided on the top surface of the glass of the vehicle based on a variation of capacitance
Implementation Method 2
an amount of rainfall is determined by using an variation of intensity of light received by the light receiving unit due to the variation of a light refractive index by rain drops
Implementation Method 3
a transparent substrate interposed between the outer and inner glasses
Implementation Method 4
the sensing electrode may serve as a hot-wire electrode
Data Source
AI summary
According to one embodiment, there is provided a sensor for a vehicle, which includes: a vehicle glass; a substrate disposed on the vehicle glass; a transparent sensing electrode disposed on the substrate; and a wire electrode connected to the sensing electrode, wherein the sensing electrode comprises a first sensing electrode and a second sensing electrode spaced apart from the first sensing electrode.