FMCW LiDAR Scanning Layout With Parallel Optical Matrices
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Solution Overview
Problem
Existing FMCW-LiDAR devices struggle to collect sufficient distance information in a short time for real-time three-dimensional environmental profiling, particularly in autonomous vehicles, due to challenges in signal attenuation and noise interference in large distribution matrices.
Innovation Solution
A scanning device with multiple parallel optical processing units, each comprising a distribution matrix, free space couplers, and detectors, that minimizes signal attenuation and noise by using a common light source and polarization-sensitive components to enable simultaneous range measurements with high signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large distribution matrix with many optical switches is used to scan multiple directions, then the scanning coverage and field of view are improved, but the signal attenuation and noise interference increase, reducing measurement precision
Solution Approach 1:
The patent divides the large distribution matrix into multiple smaller distribution matrices, each handling a specific scanning sector. This segmentation reduces the number of optical switches in each matrix, minimizing signal attenuation and noise while maintaining comprehensive scanning coverage through coordinated operation of multiple matrices.
Solution Approach 2:
The patent introduces a vertical dimension by stacking multiple distribution matrices in layers, allowing optical signals to be distributed across different spatial planes. This three-dimensional arrangement enables comprehensive angular coverage while keeping each individual matrix compact, thereby reducing signal loss and improving measurement precision.
2Measurement precision
If the number of optical switches in the distribution matrix is increased to achieve higher scanning resolution, then the scanning precision is improved, but the signal loss and noise interference increase
Solution Approach 1:
The patent segments the optical switching function across multiple smaller matrices rather than using one large matrix with many switches. Each small matrix has fewer switches, reducing cumulative signal loss, while the collective arrangement of multiple matrices achieves the required scanning resolution through spatial distribution.
Solution Approach 2:
The patent uses multiple distribution matrices that collectively provide scanning resolution exceeding what a single matrix would need to provide alone. This distributed approach allows each matrix to operate with fewer switches, reducing signal loss while the combined system achieves high scanning resolution.
3Productivity
If multiple optical processing units are used to increase the pixel rate and reduce measurement time, then the productivity is improved, but the device complexity increases
Solution Approach 1:
The patent divides the optical processing function into multiple independent processing units, each capable of simultaneous operation. This segmentation enables parallel processing of optical signals from different directions, significantly increasing the pixel rate and reducing measurement time while maintaining manageable complexity through modular design.
Solution Approach 2:
The patent arranges multiple distribution matrices in vertical layers, creating a three-dimensional optical processing architecture. This spatial arrangement allows multiple processing units to operate in parallel without excessive interconnections, increasing productivity while controlling device complexity through structured spatial organization.
4Device complexity
If a single large distribution matrix is used to distribute optical signals, then the device complexity is reduced, but the signal attenuation increases and requires higher optical power
Solution Approach 1:
The patent segments the optical signal distribution function across multiple smaller matrices rather than using one large matrix. This reduces the number of switching stages in each matrix, minimizing signal attenuation and allowing operation with lower optical power while the coordinated system maintains comprehensive coverage.
Solution Approach 2:
The patent uses multiple distribution matrices that collectively provide the full distribution capability, allowing each individual matrix to have fewer switches and lower signal loss. This distributed approach reduces the optical power requirement compared to a single large matrix while achieving the same overall functionality.
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 device achieves reliable and accurate range and velocity measurements with high pixel rate and reduced signal loss, ensuring robust performance in autonomous driving applications without the need for high-intensity optical signals that could damage optical switches.
Implementation Method 1
Each free space coupler is configured to outcouple the optical output signal guided in the associated optical waveguides into the free space, and to couple an optical output signal, which was reflected on the object, into the associated optical waveguide as an optical measurement signal
Implementation Method 2
Each processing unit further comprises a detector configured to detect a superposition of the optical measurement signal with the optical output signal generated by the light source and supplied via a local oscillator light path
Implementation Method 3
a polarization sensitive light splitter directing the optical measurement signal to the detector
Implementation Method 4
a deflection optical unit configured to deflect the output signals outcoupled from the free space couplers so that they are emitted in different directions
Data Source
AI summary
A device for scanning range measurement to an object has a light source that generates an optical output signal having a varying frequency. A plurality of optical processing units are connected optically in parallel to the light source. Each processing unit has an optical distribution matrix with a plurality of optical switches that distribute the optical output signals from the light source selectively to different optical waveguides. A plurality of free space couplers outcouple the optical output signals into the free space, and couple optical output signals, which were reflected on the object, into the associated optical waveguides as optical measurement signals. A polarization sensitive light splitter directs the optical measurement signals detectors that detect a superposition of the optical measurement signals with the optical output signals supplied via a local oscillator light path.