Addressable VCSEL LiDAR Scanning for Dense Point Clouds
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Solution Overview
Problem
Current Lidar systems face challenges in achieving high-density point clouds with a small form factor, low cost, and reduced power consumption, as traditional methods either increase the system's bulkiness or complicate the design with mechanical scanners and high power consumption.
Innovation Solution
A Lidar system with a limited number of laser emitters arranged in a 1D array, fabricated monolithically on a semiconductor substrate, allows for individually addressable laser emitters and photosensors, and uses a mechanical scanner to scan horizontally while emitters are activated vertically, reducing power consumption and cross-talk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of laser emitters is increased to enhance point cloud density, then the resolution ability is improved, but the form factor increases and cost increases
Solution Approach 1:
The laser emitter array is segmented into multiple independently controllable groups or rows. Instead of activating all emitters simultaneously, the system activates only specific segments corresponding to regions of interest, thereby maintaining high point cloud density in critical areas while reducing the number of active emitters and lowering power consumption and form factor requirements.
Solution Approach 2:
The system dynamically controls which laser emitters are activated based on real-time scanning requirements and regions of interest. This dynamic activation pattern allows the Lidar to achieve high effective point cloud density where needed while keeping the overall system compact and power-efficient by not requiring all emitters to be active at once.
2Ease of operation
If all laser emitters are activated simultaneously to ease operation, then the ease of operation is improved, but the power consumption increases and cross-talk increases
Solution Approach 1:
Instead of simultaneous activation, laser emitters are activated in periodic sequences or time-multiplexed patterns. Each emitter or group of emitters is activated at different time intervals, which reduces peak power consumption and eliminates cross-talk between adjacent emitters while maintaining operational simplicity through automated sequential control.
3Measurement precision
If a 2D array of laser emitters is used to increase resolution, then the resolution ability is improved, but the power consumption increases
Solution Approach 1:
The 2D emitter array is segmented into multiple independently controllable rows or columns. The system activates only the necessary segments for each scanning frame based on the field of view requirements, rather than activating the entire 2D array. This segmentation maintains high resolution capability where needed while significantly reducing power consumption by keeping inactive segments dormant.
4Measurement precision
If mechanical scanners are used to direct laser beams to different directions, then the resolution ability is improved, but the device complexity increases and reliability decreases
Solution Approach 1:
The patent replaces mechanical scanning systems with an electronically controlled array of laser emitters. Each emitter can be independently directed to different angles through electronic control without moving parts, thereby achieving high resolution while eliminating mechanical complexity and improving reliability by removing vulnerable mechanical components.
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 high vertical resolution without significantly increasing power consumption, enabling efficient and cost-effective generation of dense point clouds with reduced crosstalk and mechanical complexity.
Implementation Method 1
Each of the plurality of VCSELs is configured to emit a respective laser beam through the semiconductor substrate in response to a forward bias voltage applied to a respective one of the plurality of VCSELs
Implementation Method 2
uses a mechanical scanner to scan horizontally while emitters are activated vertically
Data Source
Figure 1
Figure 2
Figure 3a
AI summary
A Lidar (100) for detecting distance information comprises an emitting module (110) emitting laser beams for detecting distance information and including a first array of laser emitters that are arranged along a vertical direction and separated into a plurality of banks each having a single semiconductor substrate; a scanner (125) configured to cause the first array of laser emitters to scan along a horizontal direction; and a detecting module (130) that detects returned laser beams generated by the first array of laser emitters and determines distance information based on returned laser beams, wherein the emitting module (110) is configured to activating a plurality of laser emitters for scanning an external environment in parallel, and the plurality of laser emitters are no more than one half of the first array of laser emitters.