Windshield Rain Sensor Module With Index-Matched Thermal Coupling
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Solution Overview
Problem
Conventional automobile rain and temperature sensors are costly due to the use of collimating and focusing lenses, and require significant modifications for different application environments, while windshield temperature sensors have mechanical components that are expensive, space-intensive, and prone to mechanical failure.
Innovation Solution
A rain and temperature sensing module with a housing containing a printed circuit board, a light emitter, a light receiver, and a temperature sensing element, where a transparent compound with a refractive index matching the windshield provides refraction-free optical coupling and thermal conductivity, eliminating the need for lenses and mechanical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If collimating and focusing lenses are used in rain sensors, then optical performance is improved, but manufacturing cost increases
Solution Approach 1:
The patent removes the collimating and focusing lenses from the optical system, extracting only the essential light-emitting and light-receiving components. This eliminates the need for expensive lens manufacturing and assembly while maintaining sufficient optical performance for rain detection applications.
Solution Approach 2:
The invention replaces expensive, precision-manufactured lenses with simpler, cheaper optical components that can be easily manufactured and replaced if needed. The system uses basic light-emitting diodes and photodetectors without requiring high-precision optical elements.
2Measurement precision
If collimating and focusing lenses are used in rain sensors, then optical performance is improved, but device complexity increases
Solution Approach 1:
The patent extracts and removes the complex lens system from the sensor design, retaining only the essential light-emitting and light-receiving elements. This simplification reduces the number of components and assembly steps while maintaining adequate optical functionality for the intended application.
Solution Approach 2:
Instead of using lenses to focus and direct light precisely, the invention inverts the approach by using a broader light distribution pattern and detecting rain through overall light attenuation. This reverse approach eliminates the need for precision optical components and their associated complexity.
3Reliability
If mechanical components are used in windshield temperature sensors, then sensing function is achieved, but reliability decreases due to mechanical failure
Solution Approach 1:
The patent replaces mechanical temperature sensing components with a non-mechanical sensing element. The temperature sensor uses an electrical or optical sensing mechanism that has no moving parts, eliminating wear, friction, and mechanical failure modes while maintaining accurate temperature measurement capability.
Solution Approach 2:
The temperature sensing element operates without mechanical actuation or adjustment mechanisms. The sensing component passively measures temperature through electrical resistance changes or other non-mechanical physical effects, requiring no maintenance or mechanical intervention throughout its service life.
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 reduces manufacturing costs, allows for easier configuration changes, and prevents mechanical failures, while maintaining effective operation of windshield wipers and defogging systems.
Implementation Method 1
a transparent compound with a refractive index matching the windshield provides refraction-free optical coupling
Implementation Method 2
the transparent compound provides a thermally conductive medium between the cover plate and the temperature sensing element
Data Source
AI summary
A rain and temperature sensing module including a housing having a cover plate formed of a transparent material, a printed circuit board disposed within the housing and having a light emitter, a light receiver, and a temperature sensing element disposed thereon, a transparent compound disposed within the housing and covering the light emitter, the light receiver, and the temperature sensing element, the transparent compound filling a space between the printed circuit board and the cover plate, wherein the transparent compound has a refractive index that is substantially equal to a refractive index of the cover plate, and wherein the transparent compound provides a thermally conductive medium between the cover plate and the temperature sensing element.