Rearview Mirror Position Sensing With Asymmetrical Magnetic Field
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Solution Overview
Problem
Existing vehicular rearview assembly systems using permanent magnets and magnetic sensors for determining axis orientation have accuracy limitations and cannot account for background magnetic disturbances, especially when using multi-jointed mounts.
Innovation Solution
A rearview assembly with an asymmetrical magnetic unit and a sensor system that uses magnetic field information to determine the position of a main unit relative to a mount along three perpendicular axes, incorporating a pole piece to extend the magnetic field and enable accurate positioning even when the system is unpowered or stationary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If permanent magnets and magnetic sensors are used in a ball-socket joint or on the electronic board, then the system can determine position and orientation, but the accuracy is limited and background magnetic disturbances cannot be accounted for
Solution Approach 1:
The patent employs an asymmetrical magnetic field configuration using multiple magnets arranged in a specific non-symmetrical pattern. This asymmetrical arrangement creates a unique magnetic field signature that allows the sensor to distinguish between the actual mirror position and background magnetic disturbances, thereby improving measurement precision while accounting for environmental magnetic interference.
Solution Approach 2:
The patent introduces an intermediary computational process that analyzes the magnetic field data from the sensor. This intermediary processing layer distinguishes between the magnetic field signals caused by the mirror's actual position and those caused by background disturbances, effectively filtering out harmful magnetic interference while preserving accurate position information.
2Adaptability or versatility
If magnets or sensors are placed in a ball-socket joint or on the electronic board, then position sensing is enabled, but the system does not work with multi-jointed mounts
Solution Approach 1:
The patent implements a universal position sensing system that functions reliably across single-jointed and multi-jointed mount configurations. The asymmetrical magnetic field configuration and computational analysis approach are designed to be agnostic to the specific joint type, allowing the same sensor system to accurately determine mirror position and orientation regardless of whether it's mounted on a simple ball-socket or a complex multi-jointed assembly.
3Use of energy by moving object
If the magnetic field is always on, then continuous position monitoring is possible, but energy is consumed even when the mirror is stationary
Solution Approach 1:
The patent implements a periodic or on-demand magnetic field activation strategy rather than continuous operation. The magnetic field is activated only when position sensing is required, such as during mirror adjustment or when the vehicle is in use, and deactivated when the mirror is stationary and not in use. This periodic action significantly reduces energy consumption while maintaining reliable position sensing availability when needed.
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 solution provides accurate and reliable determination of the main unit's position relative to the mount across three axes, overcoming the limitations of previous systems by using an asymmetrical magnetic field to enhance sensor data and account for background disturbances.
Implementation Method 1
an asymmetrical magnetic unit including a magnet received in the cavity of the ball joint portion and a pole piece coupled with the magnet and positioned outside the cavity
Data Source
AI summary
A rearview assembly includes a mount having a first end and a second end that includes a first joint portion and a main unit including a planar front face secured to a housing. The housing has a second joint portion disposed opposite the planar front face. The socket rotatably receives the ball joint portion such that the main unit is articulable on the mount along three perpendicular axes. The assembly further includes an asymmetrical magnetic unit secured to the first joint portion. a sensor mounted in the housing of the main unit and positioned in proximity to the asymmetrical magnet unit, and a processor in communication with the sensor to receive magnetic field information from the sensor and to determine a position of the main unit in relation to the mount based on the magnetic field information.