Rotatable Concave Mirror LiDAR for Compact High-Precision Scanning
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Solution Overview
Problem
Existing LiDAR systems face challenges in reducing size while maintaining high precision and increasing the optical aperture cross-section to improve signal-to-noise ratio, especially for distant objects.
Innovation Solution
A 2D scanning high precision LiDAR system using a combination of a rotatable concave reflector and light beam steering devices, including a polyhedron reflector, to steer light pulses both vertically and horizontally, enhancing the optical aperture and collection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If on-chip MEMS are used to steer light pulses, then the size of LiDAR system is reduced, but the optical aperture cross-section becomes too small (less than 5mm) to distinguish reflected light from background noise at longer distances
Solution Approach 1:
The patent combines a rotatable concave mirror and a beam steering device into a single integrated LiDAR system. The concave mirror serves dual functions: it focuses incident light to a focal point and simultaneously steers the beam in different directions through rotation. This merging of functions allows the system to achieve both compact size and sufficient optical aperture cross-section (greater than 5mm) to distinguish reflected light from background noise at distances up to 100 meters.
Solution Approach 2:
The patent employs a rotatable concave mirror that can dynamically change the direction of the light beam by rotating around an optical axis. This dynamic steering mechanism allows the system to scan the field of view while maintaining a compact form factor. The rotatable component enables the small aperture to effectively collect and direct light pulses to and from distant objects, resolving the contradiction between small size and sufficient aperture cross-section.
2Measurement precision
If a larger optical aperture cross-section is used to boost signal-to-noise ratio, then distant objects can be distinguished from background noise, but the LiDAR system becomes bulky and expensive
Solution Approach 1:
The patent utilizes a concave mirror with a curved reflective surface to focus and steer light pulses. The curved geometry of the concave mirror allows it to converge parallel light rays to a focal point and redirect them in different directions upon rotation. This curved optical element achieves effective light concentration and steering with a compact aperture cross-section, avoiding the need for large bulky components while maintaining sufficient signal-to-noise ratio for distant object detection.
3Measurement precision
If conventional LiDAR system configurations are used to achieve high precision, then measurement accuracy is improved, but the system becomes prohibitively costly to integrate with vehicles
Solution Approach 1:
The patent designs a LiDAR system with multi-functional components where the rotatable concave mirror serves both as a light-focusing element and a beam-steering mechanism. This universal component approach reduces the total number of parts needed in the system, simplifying manufacturing and integration with vehicles. The single rotatable concave mirror replaces what would traditionally require separate focusing optics and steering mechanisms, thereby reducing integration cost while maintaining high ranging precision through the coaxial illumination and detection architecture.
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 system achieves a higher resolution and improved signal-to-noise ratio by interlacing sub-frames and increasing the density of sampled points, while maintaining a compact size suitable for integration with vehicles.
Implementation Method 1
Each beam steering apparatus comprises a rotatable concave reflector... the light pulses directed by the rotatable concave reflector... can be further directed to a different direction by the light beam steering device or the rotatable concave reflector
Implementation Method 2
a light beam steering device disposed at a location such that the light pulses directed by the rotatable concave reflector... can be further directed to a different direction by the light beam steering device
Data Source
AI summary
The present disclosure describes a system and method for coaxial LiDAR scanning. The system includes a first light source configured to provide first light pulses. The system also includes one or more beam steering apparatuses optically coupled to the first light source. Each beam steering apparatus comprises a rotatable concave reflector and a light beam steering device disposed at least partially within the rotatable concave reflector. The combination of the light beam steering device and the rotatable concave reflector, when moving with respect to each other, steers the one or more first light pulses both vertically and horizontally to illuminate an object within a field-of-view; obtain one or more first returning light pulses, the one or more first returning light pulses being generated based on the steered first light pulses illuminating an object within the field-of-view, and redirects the one or more first returning light pulses.