Rearview Mirror Camera Zones for Glare-Safe IR Occupant Monitoring
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Solution Overview
Problem
Existing interior rearview mirrors with driver monitoring systems face challenges in maintaining adequate infrared and near-infrared light transmissivity during dimming, which affects the functionality of driver and occupant monitoring systems by reducing the quality and reliability of image data capture.
Innovation Solution
The system adjusts the reflectance of the mirror reflective element to maintain a minimum threshold level of infrared and near-infrared light transmissivity by limiting dimming based on glare levels and passenger presence, and optionally increasing light emitter intensity, to ensure effective monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the variable reflectance mirror reflective element is electrically powered to dim the rearview mirror to reduce visible light reflectance, then glare reduction is improved, but infrared and near infrared light transmissivity is reduced which worsens driver monitoring system functionality
Solution Approach 1:
The patent applies local quality by implementing region-specific optical properties within the mirror assembly. The variable reflectance mirror element is configured to selectively control different wavelengths of light independently - allowing high IR/NIR transmissivity in monitoring zones while providing visible light dimming in driver viewing zones. This enables the system to maintain different optical characteristics in different regions of the same mirror assembly, resolving the contradiction between glare reduction and monitoring system functionality.
Solution Approach 2:
The patent implements dynamics by making the mirror assembly's optical properties adjustable and changeable in real-time. The system dynamically controls the reflectance and transmissivity characteristics of the mirror element based on operational conditions, allowing it to switch between glare-reducing mode and monitoring-optimized mode. This dynamic adjustment capability enables the system to adapt to different situations, resolving the fixed trade-off between visible light reduction and IR/NIR transmission.
2Illumination intensity
If the mirror reflective element reflectance is reduced to improve driver comfort during daytime, then visible light transmission is improved, but infrared light transmissivity for passenger detection is reduced
Solution Approach 1:
The patent applies local quality by creating distinct optical zones within the mirror assembly. Certain regions are optimized for visible light transmission to provide driver comfort, while other regions maintain high IR/NIR transmissivity to ensure accurate passenger detection. This spatial differentiation of optical properties allows the system to simultaneously satisfy both requirements without compromise.
Solution Approach 2:
The patent implements parameter changes by controlling the optical characteristics of the mirror element across different wavelength parameters. The system independently adjusts visible light reflectance and IR/NIR light transmissivity parameters, allowing optimization of each parameter for its specific function. This multi-parameter control resolves the contradiction by decoupling the optical performance at different wavelengths.
3Reliability
If the system increases light emitter intensity to compensate for reduced IR light transmissivity during mirror dimming, then monitoring system functionality is maintained, but energy consumption increases
Solution Approach 1:
The patent applies local quality by concentrating the light emitter's energy output in specific directional zones and wavelength ranges that maximize transmission through the mirror element's optimized regions. Rather than uniformly increasing intensity across all directions, the system targets energy delivery to areas where the mirror assembly has high IR/NIR transmissivity, reducing overall energy consumption while maintaining monitoring functionality.
Solution Approach 2:
The patent replaces the mechanical approach of uniformly increasing light emitter power with an optical system that uses the variable reflectance mirror element's wavelength-selective transmission properties. Instead of compensating for transmission loss through brute-force intensity increase, the system substitutes an optical solution that leverages the mirror's ability to selectively transmit different wavelengths, thereby maintaining functionality with lower energy input.
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 approach enhances the quality and reliability of image data capture for driver and occupant monitoring systems by optimizing light transmissivity, particularly in the presence of glare and varying environmental conditions.
Implementation Method 1
a variable reflectance mirror reflective element and reflectance of the variable reflectance mirror reflective element is adjusted responsive to an electrical current applied to the variable reflectance mirror reflective element
Implementation Method 2
A light emitter is accommodated by the mirror head and operable, when electrically powered to emit light, to emit infrared (IR) light or near infrared (NIR) light
Implementation Method 3
the camera captures image data representative of IR light or NIR light reflected from objects at the portion of the interior cabin of the vehicle that passes through the variable reflectance mirror reflective element
Data Source
AI summary
A vehicular occupant monitoring system includes a vehicular interior rearview mirror assembly having a mirror head that accommodates a variable reflectance mirror reflective element. A camera is accommodated by the mirror head and views through the variable reflectance mirror reflective element. A light emitter is accommodated by the mirror head and is operable to emit near infrared light that passes through the mirror reflective element. Responsive to detection of glare light at the variable reflectance mirror reflective element, and responsive to determining presence of a passenger in the vehicle, reflectance of a principal viewing region of the variable reflectance mirror reflective element is electrically reduced to a first reflectance level and reflectance of a camera region and a light source region of the variable reflectance mirror reflective element is electrically reduced to a second reflectance level that is a higher reflectance level than the first reflectance level.