Multifaceted LIDAR Deflector for Regular Near-Horizontal Scanning
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Solution Overview
Problem
Conventional LIDAR systems on vehicles face challenges in achieving accurate range detection and object identification due to irregular scanning patterns caused by reflective surfaces, which complicate the detection of objects, especially at near horizontal inclination/declination angles.
Innovation Solution
The use of multifaceted deflectors with blazed gratings in LIDAR systems replaces reflective surfaces, allowing for wider horizontal coverages and improved detection capabilities by deflecting optical beams at near horizontal inclination/declination angles, enhancing the system's ability to identify objects within its vicinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reflective surfaces are used in conventional LIDAR systems, then the system structure is simple, but the scanning pattern becomes irregular and detection accuracy deteriorates
Solution Approach 1:
The deflector surface is segmented into multiple facets with different orientations. Each facet is configured to deflect the optical beam at a specific angle, creating a regular scanning pattern. This segmentation of the continuous reflective surface into discrete angular zones resolves the contradiction by maintaining structural simplicity while achieving precise, regular scanning coverage.
Solution Approach 2:
Different regions of the deflector are assigned different local optical properties through varying facet orientations. Each facet's normal vector is specifically oriented to achieve the desired deflection angle for its local region, enabling regular scanning patterns while maintaining overall system simplicity through localized geometric adjustments rather than complex active control.
2Stability of the object's composition
If multifaceted deflectors with blazed gratings are used, then scanning pattern regularity improves, but device complexity increases
Solution Approach 1:
The deflector is divided into multiple facets, each with a specific orientation and blazed grating structure. This segmentation creates distinct angular zones that collectively form a regular scanning pattern, resolving the contradiction by organizing complexity into manageable, repeating geometric units rather than a monolithic complex structure.
Solution Approach 2:
The blazed grating structure introduces asymmetric surface profiles on each facet, optimized for specific diffraction angles. This asymmetric design enables precise control of the scanning pattern regularity while maintaining manufacturing simplicity through standardized asymmetric unit repetition across the deflector surface.
3Reliability
If optical beams are deflected at near horizontal inclination/declination angles, then object detection capability improves, but vertical distortion increases
Solution Approach 1:
The system transitions from purely horizontal scanning to three-dimensional angular scanning by introducing controlled vertical inclination angles. This dimensional extension allows the optical beam to access near-horizontal targets while the multifaceted structure compensates for vertical distortion through coordinated facet orientation, resolving the contradiction by operating in expanded angular space.
Solution Approach 2:
The facet orientations are specifically parameterized to achieve near-horizontal deflection angles. By adjusting the inclination and azimuth parameters of each facet's normal vector, the system optimizes detection capability for surface vehicles while compensating for vertical distortion through precise angular parameter control.
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
This configuration improves the LIDAR system's range accuracy and object detection by providing a more regular and symmetrical scanning pattern, especially beneficial for surface vehicles, with wider azimuthal fields of view and reduced vertical distortion, simplifying the identification of objects at small declination angles.
Implementation Method 1
At least one facet is covered with a grating having a facet ruling spacing selected to deflect the optical beam at the first incident angle into a deflected angle within ten degrees of the facet normal direction
Implementation Method 2
a facet of the plurality of outward facing facets is covered with an optical element having a spacing that is less than ten times the operating wavelength
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.