LiDAR Scanning Mirrors Array for Dense Point Clouds
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
State-of-the-art LiDAR systems face limitations in point cloud density due to a limited number of laser sources and detectors, which restricts their ability to generate dense point clouds at a reasonable frame/sweep rate, especially in applications like autonomous driving, where high resolution and field of view are crucial.
Innovation Solution
The use of a scanning mirrors array (SMA) that varies the direction of light projection and detection to maximize light capture, combined with modulation of light power or wavelength to enable unambiguous estimation of time-of-flight or phase lag, allowing for dense depth map formation with a minimal number of light sources and detectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple laser sources and detectors are used to increase point cloud density, then measurement precision and point cloud density improve, but device complexity and cost increase
Solution Approach 1:
The patent divides the scanning function into multiple independent scanning mirrors that can operate simultaneously at different angles. Each mirror handles a specific angular sector, allowing parallel light projection and detection without requiring multiple complete laser-detector pairs. This segmentation of the scanning function maintains high point cloud density while reducing the number of laser sources and detectors needed.
Solution Approach 2:
The patent introduces angular diversity as an additional dimension by using scanning mirrors to project light at multiple angles simultaneously. Instead of increasing point cloud density by adding more laser-detector pairs in the same spatial configuration, the system exploits the angular dimension to capture reflected light from multiple directions, thereby increasing density without proportionally increasing component count.
2Productivity
If laser pulsing rate is increased to improve frame rate, then productivity improves, but reliability decreases due to temperature rise and detection ambiguity
Solution Approach 1:
The patent uses periodic modulation of the laser pulse timing synchronized with the scanning mirror rotation. By issuing pulses at specific periodic intervals that correspond to known mirror positions, the system can operate at high frame rates while maintaining reliable detection. The periodic nature of the scanning motion allows the system to predict when reflected light from each pulse will return, eliminating detection ambiguity even at high pulsing rates.
Solution Approach 2:
The patent implements feedback by using the known scanning mirror positions and timing information to correlate detected reflected light with specific emitted pulses. The system continuously tracks mirror angular position and uses this feedback to determine which pulse each reflection corresponds to, enabling high-speed operation without losing the ability to unambiguously identify pulse-reflection pairs.
3Reliability
If large lenses are used to capture more reflected light, then detection capability improves, but field of view decreases due to large focal distance
Solution Approach 1:
The patent segments the field of view into multiple angular sectors, each handled by scanning mirrors oriented at different angles. Instead of using a single large lens to capture light from the entire field of view, the system uses multiple smaller optical paths, each with its own scanning mirror and detector subset. This allows the use of smaller lenses while maintaining comprehensive light capture across the full field of view through angular segmentation.
Solution Approach 2:
The patent exploits the angular dimension by using scanning mirrors to redirect light from different field of view sectors to different detectors. This allows the system to achieve wide field of view coverage without requiring large focal distances, as the angular separation is used to spatially distribute light from different directions to appropriate detection elements.
4Productivity
If multiple laser sources are assigned to each detector to increase pulsing rate, then productivity improves, but device complexity and cost increase
Solution Approach 1:
The patent segments the pulsing function across multiple scanning mirrors rather than assigning multiple lasers to each detector. Each scanning mirror can independently modulate and project light pulses at high rates in its specific angular sector. This segmentation allows the system to achieve high overall pulsing rates without requiring multiple laser sources per detector, as each mirror-detector pair operates independently at high speed.
Solution Approach 2:
The patent uses dynamic scanning mirrors that can rapidly change their angular position and timing characteristics. This dynamic capability allows a single laser source paired with a scanning mirror to effectively achieve high pulsing rates by directing pulses sequentially across multiple angular sectors, eliminating the need for multiple static laser sources while maintaining high productivity.
Data Source
AI summary
A LiDAR device that transmits a single or multiple continuous or intermittent laser beams to the environment and detects the reflected light on one or more detectors. The LiDAR device may include a scanning mirrors array composed of a single or multiple moving mirrors capable of changing the direction of the transmitted light. The scanning mirrors array may also include sensors and actuators which can be used to precisely control or measure the position of the mirrors. The LiDAR device may also include a lens that focuses the light captured by the mirror(s) onto a single or a multitude of detectors. The device may include laser sources and detectors operating in various wavelengths. The LiDAR device may also include laser power modulation mechanisms at a single or multitude of frequencies to improve signal detection performance and remove any ambiguity in range calculation.