Multifaceted LIDAR Deflector Using Blazed Gratings for Wider Scanning
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Solution Overview
Problem
Conventional LIDAR systems using reflective surfaces produce irregular scanning patterns that complicate the detection and identification of objects, especially for surface vehicles, due to issues with beam steering and scanning efficiency.
Innovation Solution
Implementing a multifaceted deflector with blazed gratings in the LIDAR system to replace reflective surfaces, allowing for wider horizontal coverages and achieving near-horizontal inclination/declination angles, thereby improving object detection and identification capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional reflective surfaces are used in LIDAR systems, then the system structure is simple, but the scanning pattern becomes irregular and object detection accuracy deteriorates
Solution Approach 1:
The deflector surface is segmented into multiple facets, each with a specific orientation angle. This segmentation allows the system to create regular scanning patterns by directing the laser beam through multiple discrete reflection paths, thereby improving object detection accuracy while maintaining a relatively simple overall structure.
Solution Approach 2:
Different regions of the deflector surface are given different local properties through varying facet orientations. Each facet is specifically angled to redirect the laser beam at predetermined angles, creating a regular scanning pattern across different spatial zones. This local differentiation enables accurate object detection at various inclination angles without requiring complex dynamic adjustment mechanisms.
2Area of stationary object
If the laser beam is directed at normal incidence to the deflector, then the system configuration is simple, but the horizontal coverage is limited
Solution Approach 1:
The system deliberately uses asymmetric incidence angles rather than normal incidence. The laser beam is directed at the deflector at specific non-normal angles, and the multifaceted surface is configured with asymmetric facet orientations. This asymmetric configuration expands the horizontal coverage area by directing the beam across a wider angular range while maintaining a relatively simple optical path without requiring additional moving components.
3Area of stationary object
If multifaceted deflectors with blazed gratings are used, then near horizontal inclination angles with wider coverage are achieved, but the manufacturing complexity increases
Solution Approach 1:
The deflector is designed with specific geometric parameters including predetermined facet orientation angles and blazed grating configurations. By optimizing these parameters during the design phase, the system achieves near horizontal inclination angles with expanded horizontal coverage. The parameters are selected to balance performance requirements with manufacturing feasibility, allowing standard fabrication techniques to produce the required 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 use of blazed gratings in the multifaceted deflector enhances scanning efficiency, providing a more symmetrical and wider azimuthal field of view while maintaining vertical symmetry, simplifying object detection and identification, especially for surface vehicles.
Implementation Method 1
each facet is covered with a reflective blazed grating having a facet ruling spacing selected to deflect the optical beam at specific angles
Implementation Method 2
each facet is covered with a reflective blazed grating
Data Source
AI summary
A system and method for scanning of coherent LIDAR. The system includes a motor, a laser source configured to generate an optical beam, and a deflector. A first facet of the plurality of facets has a facet normal direction. The deflector is coupled to the motor and is configured to rotate about a rotation axis to deflect the optical beam from the laser source. The laser source is configured to direct the optical beam such that the optical beam is incident on the deflector at a first incident angle in a first plane, wherein the first plane includes the rotation axis, wherein the first incident angle is spaced apart from the facet normal direction for the first facet. A second facet of the plurality of facets includes an optical element configured to deflect the optical beam at the first incident angle into a deflected angle.