MEMS Mirror Current Path via Magnetic Field Interaction
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Solution Overview
Problem
Current Lidar systems face increased beam divergence due to metallic layers on mirrors, which cause stress and affect signal-to-noise ratio performance, necessitating a current path for beam orientation that does not require a metallic layer.
Innovation Solution
A mirror assembly with a conductor extending through a magnetic field parallel to the axis, allowing rotation without a metallic layer by using a path through torsion bars and crossbars, eliminating the need for a metallic backing on the mirror.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metallic layer is added to the back side of the mirror to separate it from the current, then the mirror can be rotated without direct current contact, but the metallic layer causes stresses that increase mirror curvature and beam divergence
Solution Approach 1:
The patent removes the metallic layer from the mirror back side, extracting the problematic element that caused stress and curvature. Instead, a non-contacting magnetic field interaction system is used to drive the mirror, eliminating the source of stress while maintaining rotational capability.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the current source and the mirror. The magnetic field mediates the force transmission without requiring direct physical contact or a metallic backing layer, thus avoiding stress-induced curvature while enabling controlled rotation.
2Ease of operation
If a metallic layer is added to the back side of the mirror, then current can be passed through the mirror, but the metallic layer increases mirror curvature and beam divergence
Solution Approach 1:
The patent replaces the mechanical/electrical conduction system (metallic layer carrying current) with a magnetic field interaction system. The Lorentz force generated by the magnetic field interacting with current in the torsion bars provides rotational actuation without requiring a metallic layer on the mirror.
3Ease of operation
If the mirror requires a metallic layer for current separation, then rotation can be achieved, but beam divergence increases impacting signal-to-noise ratio
Solution Approach 1:
The metallic layer is extracted from the mirror structure, eliminating the stress source that caused increased beam divergence. The mirror can still rotate through magnetic field interaction with current-carrying torsion bars that do not require a metallic backing on the mirror itself.
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 reduces beam divergence, improving the signal-to-noise ratio and maintaining the mirror's curvature, enhancing the Lidar system's object detection capabilities.
Implementation Method 1
a first current passing through the first conductor interacts with the first magnetic field to induce a first rotation of the first frame about the first axis
Implementation Method 2
a second current passing through the second conductor in the direction of the second axis interacts with the second magnetic field to induce a second rotation of the second frame about the second axis
Data Source
AI summary
A Lidar system, a mirror assembly for a Lidar system and method of operating the mirror assembly. The mirror assembly of the Lidar system includes a first frame and a first conductor. The first frame is rotatable about a first axis. The first conductor extends along the first frame to one side of the first axis. The first conductor extends through a first magnetic field on the one side of the first axis in a direction parallel to the first axis. A first current is passed through the first conductor to interact with the first magnetic field to induce a first rotation of the first frame about the first axis.