Non-linear Springs for MEMS Mirror Array Synchronization
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Solution Overview
Problem
LiDAR systems are bulky, making it challenging to move mirrors quickly for fast scanning while maintaining light intensity, and synchronizing movement of microelectromechanical system (MEMS) mirrors in arrays is difficult, which affects the accuracy and efficiency of beam steering in autonomous vehicles.
Innovation Solution
A device for beam steering in LiDAR systems using a mirror mechanically coupled with a spring and a combdrive actuator, with a limiter to control the mirror's motion, allowing for synchronized movement of multiple MEMS mirrors to act as a single reflective surface, driven nonlinearly to match amplitude and phase, and using magnetic repulsion or hard stops to limit rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the mirror size is increased to maintain light intensity, then light intensity is improved, but scanning speed deteriorates due to increased mass
Solution Approach 1:
The patent divides a single large mirror into an array of multiple smaller MEMS mirrors. Each micro-mirror maintains sufficient size for light reflection while the collective array provides the necessary light intensity. This segmentation allows faster scanning speed for individual mirrors while the array as a whole maintains adequate light intensity for LiDAR applications.
Solution Approach 2:
The patent combines multiple smaller MEMS mirrors into a unified array that functions collectively as a single reflective surface. When synchronized, the mirrors work together to steer light beams, achieving both the light intensity of a large mirror and the scanning speed of smaller components.
2Speed
If multiple MEMS mirrors are used to increase scanning speed, then scanning speed is improved, but synchronization difficulty increases
Solution Approach 1:
The patent incorporates feedback mechanisms to monitor and adjust the motion of individual MEMS mirrors in real-time. By detecting deviations from synchronized motion and applying corrective control signals, the system maintains coordination across all mirrors despite variations in individual mirror responses.
Solution Approach 2:
The patent dynamically adjusts operating parameters such as drive frequency, amplitude, and phase for each MEMS mirror to achieve synchronization. By tuning these parameters based on detected conditions, the system coordinates the mirrors' motion to function as a unified scanning surface.
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 enables faster scanning speeds with reduced light intensity loss and improved accuracy by synchronizing the motion of multiple MEMS mirrors, enhancing the performance of LiDAR systems in autonomous vehicles.
Implementation Method 1
a spring mechanically coupled with the mirror
Implementation Method 2
a combdrive actuator configured to move the mirror
Implementation Method 3
using magnetic repulsion or hard stops to limit rotation
Data Source
AI summary
An array of micro mirrors is used to beam steer a laser for Light Detection and Ranging (LiDAR) applications. The array of micro mirrors are driven in a nonlinear motion to synchronize motion of the micro mirrors in the array.