Vehicle Rain Sensor Calibration via Adjustable Light Incidence
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Solution Overview
Problem
Existing rain sensors struggle with inaccurate measurement of rain quantity due to light being misdirected away from the receiver, leading to difficulty in distinguishing between no, little, or much rain on the vehicle window.
Innovation Solution
The method involves varying the incidence angle of light emitted by the transmitter without moving the transmitter or receiver, adjusting the light path to ensure sufficient light reaches the receiver, thereby enhancing measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the transmitter and receiver are arranged at a distance from each other to increase measurement accuracy, then the light path becomes more complex and may miss the receiver, but moving them for calibration increases device complexity and installation difficulty
Solution Approach 1:
The patent applies the dynamics principle by making the incidence angle adjustable rather than fixed. The calibration unit varies the incidence angle dynamically to optimize light transmission through the window, allowing the system to adapt to different installation conditions and window properties without physically relocating the transmitter or receiver. This resolves the contradiction by maintaining a fixed physical arrangement while achieving optimal measurement through parameter adjustment.
Solution Approach 2:
The patent implements parameter changes by modifying the incidence angle of light as a controllable parameter. The calibration unit changes this parameter to maximize light transmission to the receiver, thereby improving measurement accuracy without increasing device complexity or requiring physical movement of components. This directly addresses the contradiction by optimizing performance through parameter adjustment rather than structural modification.
2Ease of manufacture
If the incidence angle is fixed during installation, then the device structure is simple, but light may be misdirected away from the receiver leading to inaccurate measurements
Solution Approach 1:
The system transitions from a static fixed incidence angle to a dynamic adjustable incidence angle. The calibration unit enables the incidence angle to be varied and optimized after installation, maintaining the simplicity of the initial installation while achieving accurate measurements through subsequent parameter optimization. This resolves the contradiction between ease of manufacture and measurement precision.
Solution Approach 2:
The patent applies preliminary action by performing calibration before actual rain detection. The calibration process pre-optimizes the incidence angle to ensure proper light transmission, so that when the device is used for its intended purpose, measurements are accurate without requiring complex adjustment mechanisms during operation. This maintains manufacturing simplicity while ensuring measurement precision.
3Measurement precision
If the transmitter or receiver is moved for calibration, then light transmission to the receiver is optimized, but the calibration process becomes more complex and time-consuming
Solution Approach 1:
The patent replaces the mechanical system of physically moving the transmitter or receiver with an optical control system that adjusts the incidence angle. Instead of mechanical repositioning, the calibration unit varies the angle of light incidence to optimize transmission. This substitution significantly reduces calibration time and complexity while achieving the same optimization goal.
Solution Approach 2:
The patent changes the approach from physical position parameters to optical parameter adjustment. By varying the incidence angle parameter rather than the physical position of components, the system achieves light transmission optimization without the time and complexity associated with mechanical movement and repositioning during calibration.
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 calibration method improves the rain sensor's accuracy by ensuring consistent light transmission to the receiver, enabling precise rain detection and effective windshield wiper control.
Implementation Method 1
the window may perform multiple total reflections on the light between the transmitter and the receiver. In particular, the light gets totally reflected at window-air interfaces, in particular because the refractive index of the glass forming the window is higher than that of air.
Implementation Method 2
The receiver can be a photoelectric receiver, a photodiode, an inverted LED or any other light sensitive opto-electronic element.
Data Source
AI summary
A method for calibrating a rain sensor (3), the rain sensor (3) being configured to measure a quantity of rain on a window (101) of a vehicle (100), the rain sensor (3) including a transmitter (4) and a receiver (5), the transmitter (4) being configured to emit or transmit light to the window (101) and the receiver (5) being configured to receive measurement light that is emitted or transmitted by the transmitter (4) and guided to the receiver (5) by the window (101); the method comprising:varying (S1) an incidence angle (α) of the light emitted or transmitted by the transmitter (4) to the window (101).