Solid-State MEMS Polygon Assembly for LiDAR Light Steering
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Solution Overview
Problem
Current light steering systems, such as mechanical polygon assemblies and micro-mirror arrays, face reliability and precision issues when aiming for a 360-degree field of view, leading to potential blind spots and reduced performance due to mechanical wear, misalignment, and synchronization challenges.
Innovation Solution
A solid-state light steering system utilizing a micro-electromechanical system (MEMS) with a polygon assembly on a silicon substrate, featuring a polygon with tilted facets and electrostatic actuators, which allows for precise rotation and extended field of view without the need for synchronization of multiple arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If mechanical polygon assemblies or micro-mirror arrays are used for light steering, then the field of view can be extended, but mechanical wear and misalignment occur leading to reduced reliability and precision
Solution Approach 1:
The patent replaces mechanical polygon assemblies and micro-mirror arrays with a solid-state MEMS-based light steering system. The MEMS device uses electrostatic actuators to rotate a polygon mirror without mechanical contacts, eliminating wear and improving reliability while maintaining the ability to achieve 360-degree field of view through precise electrostatic control of the polygon's rotation angle.
Solution Approach 2:
The patent changes the operating parameters by using electrostatic fields instead of mechanical drive mechanisms. The polygon mirror's rotation angle is controlled by applying specific voltages to electrostatic actuators, allowing precise control without mechanical wear. This parameter change from mechanical to electrostatic control resolves the contradiction between extended field of view and reliability.
2Area of stationary object
If mechanical polygon assemblies are used for light steering, then the field of view can be extended, but synchronization challenges and misalignment occur leading to reduced precision
Solution Approach 1:
The patent replaces mechanical synchronization mechanisms with electrostatic control of the polygon mirror rotation. The MEMS device uses voltage-controlled electrostatic actuators to precisely position the polygon mirror at required angles, eliminating mechanical synchronization challenges and misalignment issues while achieving precise light steering across the 360-degree field of view.
Solution Approach 2:
The patent uses a single solid-state MEMS polygon mirror to replicate the function of multiple mechanical mirror arrays, eliminating synchronization challenges. The single MEMS device can be precisely controlled to achieve the same light steering functionality without the complexity of synchronizing multiple mechanical components, thereby improving precision.
3Reliability
If electrostatic actuators are used in the MEMS device, then mechanical wear is eliminated, but the device complexity increases
Solution Approach 1:
The patent merges the polygon mirror and electrostatic actuators into a single integrated MEMS device fabricated on a silicon substrate. This integration combines multiple components into one unified structure, reducing overall device complexity while maintaining the reliability benefits of wear-free electrostatic actuation. The MEMS fabrication process naturally integrates these components, making the increased complexity manageable through standard manufacturing techniques.
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
The system provides a reliable and precise 360-degree field of view by eliminating mechanical wear and misalignment issues, enhancing the light steering system's performance and reducing blind spots through precise control of the polygon's facets.
Implementation Method 1
determine a voltage based on the target rotation angle; and apply the voltage across each actuator of the plurality of actuators, wherein the voltage causes each actuator to exert a torque on the support structure to rotate the polygon around the rotation axis
Implementation Method 2
reflect light emitted by a light source out of the LiDAR module or to reflect light received by the LiDAR module to a receiver
Data Source
AI summary
In one example, a method of fabricating a polygon assembly of a Light Detection and Ranging (LiDAR) module is provided. The method comprises: forming, on a backside surface of a first silicon-on-insulator (SOI) substrate, a multi-facet polygon of the polygon assembly; forming, on a frontside surface of the first SOI substrate, an axial portion of a support structure of the polygon assembly, the axial portion forming a stack with the polygon along a rotation axis; forming, on a frontside surface of a second SOI substrate, a plurality of radial portions of the support structure; forming, on a backside surface of the second SOI substrate, a cavity that encircles the plurality of radial portions; and bonding, based on a wafer bonding operation, the axial portion to the plurality of radial portions to form the polygon assembly.