LiDAR Scanner Using Nodding and Polygon Mirrors for Wide Field Coverage
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Solution Overview
Problem
Conventional LiDAR devices face challenges in expanding the scan field without mechanical rotation, which leads to thermal issues and stability problems, and using diffusing lenses results in decreased measurement accuracy due to laser light diffusion.
Innovation Solution
A LiDAR device design incorporating a laser emitting unit, a nodding mirror to extend the irradiation area to a line shape, and a rotating polygon mirror to expand the area to a plane shape, allowing for efficient detection of objects at longer distances with minimal power and increased received laser light without diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a diffusing lens is used to expand the scan field, then the scan field coverage is improved, but the measurement precision deteriorates due to laser light diffusion
Solution Approach 1:
The patent replaces the optical diffusing lens with a mechanical scanning system consisting of a nodding mirror and a rotating polygon mirror. The nodding mirror scans laser light in one direction to create a line-shaped irradiation area, while the rotating polygon mirror scans in another direction to expand the coverage to a plane shape, thereby achieving wide scan field coverage without diffusing the laser light and maintaining measurement precision
Solution Approach 2:
The patent divides the scan field expansion function into two separate scanning stages: the first scanning unit (nodding mirror) expands the irradiation area in one direction to form a line, and the second scanning unit (rotating polygon mirror) expands it in another direction to form a plane. This segmentation allows each unit to focus on a specific scanning direction, achieving comprehensive coverage without compromising laser beam concentration and measurement accuracy
2Area of stationary object
If mechanical rotation of the lidar device is used to expand the scan field, then the scan field coverage is improved, but the reliability deteriorates due to thermal problems and stability issues
Solution Approach 1:
The patent segments the scanning function into two independent mirror units that rotate on fixed axes rather than rotating the entire lidar device. The nodding mirror rotates on a first axis to scan in one direction, while the rotating polygon mirror rotates on a second axis perpendicular to the first, enabling scan field expansion without mechanical rotation of the main device body, thereby avoiding thermal accumulation and stability problems
Solution Approach 2:
The patent replaces the mechanical rotation of the entire lidar device with an optical scanning system using two mirrors. This substitution eliminates the need for heavy mechanical rotation of the main device, reducing thermal problems and improving reliability while maintaining the ability to expand the scan field coverage
3Area of stationary object
If laser light is diffused to cover a wider area, then the scan field coverage is improved, but the power consumption increases to maintain detection capability at longer distances
Solution Approach 1:
The patent replaces optical diffusion with mechanical scanning using two mirrors. The nodding mirror and rotating polygon mirror systematically direct the same laser beam across different areas, achieving wide scan field coverage without diffusing the light. This approach maintains laser beam concentration and intensity, allowing detection at longer distances with minimum power consumption
Solution Approach 2:
The patent employs periodic scanning motion of the nodding mirror and rotating polygon mirror to cover the entire scan field. The mirrors oscillate and rotate in periodic cycles, systematically illuminating different regions over time. This periodic action allows the same laser power to be distributed across a wide area sequentially, achieving comprehensive coverage without increasing power consumption or diffusing the laser light
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 LiDAR device to efficiently detect objects at longer distances with improved stability and accuracy, reducing power consumption and maintaining high measurement precision by expanding the scan field using a single channel of laser light.
Implementation Method 1
the first scanner comprises nodding mirror which extend the irradiation area to a line shape by changing a travel path of the laser while nodding within a preset angle range
Implementation Method 2
the second scanner comprises a rotating polygon mirror which changes the travel path of the laser which has the line-shaped irradiation area by rotating on one axis so as to extend the irradiation area to a plane shape
Implementation Method 3
a sensor which detects a laser reflected from an object located in a scanning area by the laser projected from the second scanner
Data Source
AI summary
The present invention relates to a light detecting and ranging (LiDAR) device for obtaining information on a distance from an object using laser light. A light detection and ranging (LiDAR) device according to the present invention may include: a laser emitting unit configured to emit a laser, a first scanner configured to obtain the laser emitted by the laser emitting unit and continuously change a travel path of the laser so as to extend a irradiation area to a line shape, a second scanner configured to obtain and continuously changes the travel path of the laser projected from the first scanner which has a line-shaped irradiation area, so as to extend the irradiation area to a plane shape, and a sensor configured to detect a laser reflected from an object located in a scanning area by the laser projected from the second scanner, wherein the first scanner comprises nodding mirror which extend the irradiation area to a line shape by changing a travel path of the laser while nodding within a preset angle range, and wherein the second scanner comprises a rotating polygon mirror which changes the travel path of the laser which has the line-shaped irradiation area by rotating on one axis so as to extend the irradiation area to a plane shape.