LiDAR Polygon Mirror Fluid Circulation for Noise Reduction
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Solution Overview
Problem
LiDAR systems using polygon mirrors require high-speed rotation, leading to significant noise and vibration due to air drag, which is not effectively mitigated by existing technologies.
Innovation Solution
Implementing a fluid circulation device around the polygon reflector to create a flow curtain that reduces air drag, noise, and vibration by directing fluid in a manner that aligns with the rotation direction, thereby minimizing wakes and vortices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the polygon mirror rotates at high speed to achieve required scanning performance, then the scanning speed and productivity are improved, but noise and vibration increase due to air drag
Solution Approach 1:
A fluid circulation device is introduced as an intermediary between the polygon mirror and the surrounding air. The device creates a controlled fluid environment (curtain) around the mirror that mediates the interaction between the rotating mirror and ambient air, reducing harmful air drag while allowing the mirror to rotate at high speeds for maintained scanning performance
Solution Approach 2:
The patent changes the physical state and flow parameters of the air surrounding the polygon mirror by implementing a fluid circulation system. The device adjusts fluid velocity, direction, and circulation patterns to optimize the aerodynamic environment, reducing drag forces that cause noise and vibration while preserving the high rotation speeds needed for scanning performance
2Manufacturing precision
If flat mirror surfaces are used to prevent beam divergence, then optical performance is improved, but aerodynamic drag increases due to inability to use aerodynamic shaping
Solution Approach 1:
The fluid circulation device acts as an intermediary that compensates for the non-aerodynamic shape of the flat mirror surfaces. By introducing a controlled fluid flow field around the mirror, the device mediates the aerodynamic interaction, allowing flat optical surfaces to be used without suffering from the full penalty of increased air drag
Solution Approach 2:
The patent applies local quality by creating a specialized fluid flow environment specifically around the polygon mirror surfaces. The fluid circulation device generates localized flow patterns that adhere to and smooth over the flat mirror surfaces, providing aerodynamic benefits locally at the mirror surfaces while maintaining the flat geometry required for optical precision
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 fluid circulation device effectively reduces noise and vibration, improving the operational performance of LiDAR systems by minimizing air drag and enhancing the aerodynamic stability of the polygon mirror during high-speed rotation.
Implementation Method 1
one or more fluid circulation devices configured to rotate about a second rotation axis to form a fluid circulation surrounding the plurality of reflective facets of the rotatable polygon reflector
Implementation Method 2
the fluid circulation is at least partially in the first rotation direction... effectively reduces noise and vibration, improving the operational performance of LiDAR systems by minimizing air drag
Data Source
AI summary
An optical scanning device for light ranging and detection (LiDAR) is provided. The optical scanning device comprises a rotatable polygon reflector having a plurality of reflective facets. The rotatable polygon reflector is configured to rotate about a first rotation axis in a first rotation direction. The optical scanning device further comprises one or more fluid circulation devices disposed alongside the rotatable polygon reflector or attached to the rotatable polygon reflector. The one or more fluid circulation devices are configured to rotate about a second rotation axis to form a fluid circulation surrounding the plurality of reflective facets of the rotatable polygon reflector. The fluid circulation is at least partially in the first rotation direction.