Polygon Mirror Lidar Scanner Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lidar systems face challenges in reducing power requirements, heat dissipation, and physical dimensions, while also needing to improve scanning rate and data density, particularly in vehicle applications where these factors are critical.
Innovation Solution
A lidar system utilizing a polygon mirror with multiple reflective surfaces that rotates to scan a field of regard, combined with galvanometer scanners and stationary mirrors to reduce size and acoustic noise, and featuring a dual-eye configuration with angularly offset beams for increased data density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a traditional lidar scanner is used to scan a field of regard, then the scanning function is achieved, but the physical dimensions and weight of the system increase
Solution Approach 1:
The scanning function is divided into two independent parts: a stationary polygon mirror for horizontal scanning and a rotating MEMS mirror for vertical scanning. This segmentation allows each component to be optimized independently, reducing the overall volume while maintaining full scanning capability.
Solution Approach 2:
The patent transitions from a single rotating mirror performing both horizontal and vertical scanning to a two-dimensional scanning architecture where the polygon mirror handles horizontal scanning and the MEMS mirror handles vertical scanning, effectively utilizing another dimension of motion control.
2Measurement precision
If a high-power laser source is used to improve detection range, then the detection capability is improved, but heat dissipation and power requirements increase
Solution Approach 1:
The patent replaces the traditional mechanical scanning mirror with a MEMS (Micro-Electro-Mechanical Systems) mirror, which uses electrostatic actuation instead of mechanical rotation. This substitution reduces the power requirements and heat generation while maintaining scanning functionality.
3Device complexity
If a single scanning mirror is used to reduce device complexity, then the device complexity is reduced, but the scanning rate and data density decrease
Solution Approach 1:
The scanning task is segmented between two specialized mirrors: the polygon mirror with multiple reflective surfaces for rapid horizontal scanning and the MEMS mirror for precise vertical scanning. This segmentation enables higher scanning rates and greater data density while keeping each individual component relatively simple.
Solution Approach 2:
The polygon mirror serves multiple functions by using its different reflective surfaces to scan different horizontal fields of regard, allowing a single component to perform what would otherwise require multiple separate scanning elements.
4Productivity
If the polygon mirror rotates at high speed to improve scanning rate, then the scanning rate is improved, but acoustic noise increases
Solution Approach 1:
The high-speed scanning function is segmented between the polygon mirror (horizontal) and MEMS mirror (vertical), allowing the polygon mirror to rotate at optimized speeds that balance scanning rate requirements with acoustic noise generation, while the MEMS mirror handles the remaining scanning task.
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 solution enables a compact, efficient lidar system with enhanced scanning capabilities and data density, effectively addressing the limitations of existing systems in terms of size, power, and scanning performance.
Implementation Method 1
a polygon mirror that rotates during operation, so that the output beams reflect off of different reflective surfaces of the polygon mirror
Implementation Method 2
Respective galvanometer scanners or motors can impart oscillating motion to the planar mirrors
Implementation Method 3
The stationary mirrors do not rotate or oscillate. In an example implementation, the lidar system includes stationary mirrors oriented at 45 degrees relative to incident input and output beams to provide a 90-degree fold to the beams
Implementation Method 4
at least one of the polygon mirror or the bracket includes a noise-reducing feature configured to reduce acoustic noise produced when pressure waves generated by the polygon mirror during rotation are incident on one or more components of the scanner
Data Source
AI summary
A lidar system includes a light source configured to produce a beam of light, a scanner configured to scan a field of regard of the lidar system, and a receiver configured to detect light from the beam of light scattered by a remote target. The scanner includes a polygon mirror having a block with a first wall, a second wall, and several reflective surfaces angularly offset from one another along a periphery of the block, the polygon mirror configured to rotate about a scan-mirror rotation axis to scan the beam of light across the field of regard. The scanner further includes a bracket adjacent to the polygon mirror, where at least one of the polygon mirror or the bracket includes a noise-reducing feature configured to reduce acoustic noise produced when pressure waves generated by the polygon mirror during rotation are incident on one or more components of the scanner.