VCSEL LiDAR Firing Patterns to Reduce Cross-Talk
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Solution Overview
Problem
Current lidar devices face challenges in reducing cross-talk and enhancing resolution due to limitations in existing light emitters, particularly in autonomous vehicle applications, where precise object detection and navigation are critical.
Innovation Solution
The use of individually addressable vertical-cavity surface-emitting lasers (VCSELs) with a firing circuit controlled by a controller to selectively fire VCSELs, allowing for various firing patterns that mitigate cross-talk and optimize power consumption and point cloud resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional light emitters are used in lidar devices, then the device structure is simpler, but cross-talk between adjacent channels increases and resolution deteriorates
Solution Approach 1:
The patent divides the light emitter into multiple independently controllable VCSELs arranged in an array. Each VCSEL can be selectively fired to illuminate specific regions, enabling precise spatial resolution and reduced cross-talk between adjacent detection channels. This segmentation of the emitter array allows independent control of each element to achieve higher measurement precision.
Solution Approach 2:
The patent implements dynamic control of VCSEL firing patterns through a controller that selectively activates specific VCSELs based on detection requirements. The system can dynamically adjust which VCSELs are fired and in what sequences, optimizing resolution and minimizing cross-talk adaptively rather than using a fixed emission pattern.
2Reliability
If all VCSELs are fired continuously, then complete environmental coverage is achieved, but power consumption increases
Solution Approach 1:
The patent employs partial action by selectively firing only the necessary subset of VCSELs required for current detection tasks rather than activating the entire array continuously. The controller determines which VCSELs need to be fired based on the specific environmental monitoring requirements, achieving adequate coverage with reduced energy expenditure.
Solution Approach 2:
The system implements periodic scanning patterns where VCSELs are fired in sequences rather than simultaneously. Different groups of VCSELs are activated at different time intervals to cover the entire environment, allowing the system to maintain comprehensive detection coverage while significantly reducing instantaneous and average power consumption.
3Speed
If adjacent VCSELs are fired simultaneously, then scanning speed increases, but cross-talk from retroreflector reflections increases
Solution Approach 1:
The patent applies preliminary anti-action by implementing a specific firing sequence where adjacent VCSELs are not fired simultaneously but in a staggered manner. This sequencing prevents the harmful cross-talk effects caused by simultaneous reflections from retroreflectors, as each VCSEL's reflection returns at a different time, allowing the detector to distinguish between adjacent channels effectively.
Solution Approach 2:
The system performs preliminary action by pre-planning and executing ordered firing patterns before actual detection. The controller determines the optimal firing sequence in advance, ensuring that VCSELs are activated in a pattern that minimizes cross-talk while maintaining scanning speed, rather than reacting to cross-talk issues during operation.
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 approach enhances the resolution of point clouds generated by lidar devices, reduces power consumption, and improves object detection accuracy in autonomous vehicle environments by minimizing cross-talk and optimizing light pulse emission patterns.
Implementation Method 1
an array of individually addressable vertical-cavity surface-emitting lasers (VCSELs) configured to emit light pulses into an environment surrounding the lidar device
Implementation Method 2
Each detector in the plurality of detectors is configured to detect reflections of light pulses that are emitted by one or more individually addressable VCSELs in the array and reflected by one or more objects in the environment surrounding the lidar device
Data Source
AI summary
Example embodiments relate to light detection and ranging (lidar) devices having vertical-cavity surface-emitting laser (VCSEL) emitters. An example lidar device includes an array of individually addressable VCSELs configured to emit light pulses into an environment surrounding the lidar device. The lidar device also includes a firing circuit configured to selectively fire the individually addressable VCSELs in the array. In addition, the lidar device includes a controller configured to control the firing circuit using a control signal. Further, the lidar device includes a plurality of detectors. Each detector in the plurality of detectors is configured to detect reflections of light pulses that are emitted by one or more individually addressable VCSELs in the array and reflected by one or more objects in the environment surrounding the lidar device.