Rearview Mirror Auto-Dimming With Remote Ambient Light Sensing
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Solution Overview
Problem
Existing interior rearview mirror systems face challenges in accurately determining ambient light levels due to occlusion by vehicle components and darkening layers, which affects the effectiveness of auto-dimming functionality.
Innovation Solution
The system employs a remote ambient light sensor, optionally integrated with a rain sensing device, and a glare light sensor, utilizing a LIN communication bus to control the mirror's dimming, with an additional light collecting lens at the mirror head to enhance light reception and provide a visible indicator, ensuring accurate ambient light sensing and mirror dimming even in occluded areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the ambient light sensor is located at the mirror head, then the sensor can be integrated with the mirror assembly, but the sensing area is blocked or occluded by vehicle components and darkening layers
Solution Approach 1:
The patent extracts the ambient light sensor from the mirror head location and relocates it to the vehicle hood or fender area. This separation removes the sensor from the occluded zone near the mirror assembly, allowing unobstructed light reception while maintaining functional integration through electronic communication with the mirror dimming system.
Solution Approach 2:
The patent introduces an optical pathway or light guide as an intermediary between the remote sensor location and the mirror assembly. This intermediary component transmits the ambient light signal from the hood/fender area to the mirror head, enabling accurate sensing without direct sensor placement at the occluded mirror location.
2Adaptability or versatility
If a forward viewing camera module or windshield electronics module is disposed at the in-cabin side of the windshield, then these components provide additional vehicle functions, but they block or occlude the ambient light sensor area
Solution Approach 1:
The patent extracts the ambient light sensing function from the occluded windshield area and relocates it to the vehicle exterior surfaces (hood or fender) where no such occlusion occurs. This allows the windshield electronics module and forward viewing camera to remain in place, maintaining vehicle versatility while eliminating the sensing blockage problem.
3Extent of automation
If the mirror reflective element is an electro-optic variable reflectance mirror, then the mirror can automatically dim in response to glare, but the system requires accurate ambient light sensing which is compromised by occlusion
Solution Approach 1:
The patent relocates the ambient light sensor from the occluded mirror head area to an unobstructed location on the vehicle exterior. This ensures accurate ambient light measurement for the electro-optic variable reflectance mirror, enabling reliable auto-dimming operation without the interference of vehicle components or darkening layers.
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 configuration ensures reliable ambient light sensing and effective auto-dimming of the rearview mirror, preventing occlusion by vehicle components and darkening layers, while also serving as a light indicator for vehicle status, enhancing user visibility and system operation.
Implementation Method 1
an electro-optic variable reflectance mirror reflective element that is responsive to an ambient light level and a glare light level
Implementation Method 2
a light collecting lens that is disposed at and at least partially across or along a lower region of the mirror head
Data Source
AI summary
A vehicular interior rearview mirror system includes an interior rearview mirror assembly having a mirror head adjustably mounted at a mounting structure. The mirror head includes a mirror casing and an electro-optic variable reflectance mirror reflective element. A glare light sensor senses glare light emanating from headlights of another vehicle rearward of the equipped vehicle. An ambient light sensor senses ambient light at the vehicle. The ambient light sensor comprises part of a rain sensing device disposed at an in-cabin side of a windshield of the vehicle. Mirror control circuitry is operable to adjust dimming of the mirror reflective element responsive to an output from the glare light sensor and an output from the ambient light sensor. Responsive to the output from the glare light sensor and the output from the ambient light sensor, the mirror control circuitry controls dimming of the mirror reflective element.