MEMS Laser Scanning for High-Resolution 3D TOF Mapping
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Solution Overview
Problem
Existing laser scanner systems face limitations such as bulky mechanical components, high power consumption, limited operational frequency, and restricted maximum application distance due to mechanical scanning methods and flash LIDAR's high power requirements and sensor resolution dependencies.
Innovation Solution
A laser scanner system utilizing a beam steering arrangement with microelectromechanical mirrors and sensors arranged in a grid, allowing for efficient scanning by varying light pulse directions and compensating for geometrical distortions, enabling high-resolution 3D mapping with reduced mechanical bulk and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanical scanning methods (rotating mirrors, gimbals) are used to scan laser beams, then the system can achieve 2D or 3D environmental mapping, but the system becomes bulky, consumes high power, and has limited operational frequency due to mechanical wear and inertia
Solution Approach 1:
The patent replaces mechanical scanning systems (rotating mirrors, gimbals, motors) with an optical phased array system that uses electronic phase modulation of laser beams. The beam steering is achieved through optical path difference control rather than mechanical movement, eliminating bulky mechanical components and enabling faster, wear-free operation.
Solution Approach 2:
The patent introduces a beam steering arrangement with multiple steerable beams as an intermediary between the laser source and target. This arrangement uses optical phase modulation to redirect beams electronically without mechanical moving parts, serving as a mediator that achieves scanning functionality while avoiding mechanical complexity.
2Productivity
If flash LIDAR with diffractive optics is used to illuminate full scene, then the system can capture entire environment at once, but the laser power required increases quadratically with distance and limits maximum application range to 5-10 meters
Solution Approach 1:
The patent divides the scanning task into multiple steerable laser beams that can be independently controlled and directed at different spatial locations. Instead of illuminating the entire scene simultaneously with high power, the system segments the field of view and uses multiple lower-power beams that can be sequentially or parallelly steered to cover the environment, reducing total power requirements.
Solution Approach 2:
The patent employs periodic steering of laser beams across different directions and positions. The beam steering arrangement cyclically redirects beams to scan different regions of the environment over time, enabling complete environmental mapping through time-multiplexed periodic scanning rather than simultaneous full-scene illumination.
3Measurement precision
If single laser single sensor systems use pulse time interval greater than maximum distance TOF, then the system avoids TOF measurement ambiguity, but the throughput is limited and applicability for high distances is restricted
Solution Approach 1:
The patent segments the measurement process by using multiple sensors in an array that can simultaneously detect reflected light from different spatial positions. This parallel detection capability allows the system to maintain high throughput while using shorter pulse intervals, as each sensor independently measures TOF for its corresponding beam direction without requiring long intervals to avoid ambiguity.
Solution Approach 2:
The patent adds spatial dimensionality by using a two-dimensional array of sensors that corresponds to a two-dimensional array of steerable beams. This spatial multiplexing allows simultaneous measurements across multiple directions, effectively increasing throughput by utilizing the spatial dimension rather than being constrained to sequential single-point measurements.
4Measurement precision
If array of sensors with grid arrangement is used for flash LIDAR, then the system can calculate TOF for corresponding parts of illuminated scene, but the mapping resolution depends on sensor array resolution and requires expensive high-resolution sensors
Solution Approach 1:
The patent introduces dynamic beam steering capability that allows the system to adaptively adjust beam directions and focus on regions of interest. The beam steering arrangement can dynamically reposition beams and adjust scanning patterns based on environmental features, enabling high-resolution mapping without requiring a permanently high-resolution sensor array, as resolution is achieved through temporal sampling and adaptive scanning.
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-resolution 3D mapping with improved throughput and extended maximum detection range, suitable for applications like autonomous navigation and augmented reality, while minimizing mechanical complexity and power usage.
Implementation Method 1
a first microelectromechanical, MEMS, mirror configured to oscillate around a first axis with a first oscillating angle, and a second MEMS mirror configured to oscillate around a second axis with a second oscillating angle
Implementation Method 2
a MEMS lens configured to vary the direction of transmission of the light pulses within each grid cell in the portioned FOV of the array of sensors
Implementation Method 3
configured to sense a light pulse incident thereon in response to reflection of at least one light pulse of the beam of light pulses from a field of view, FOV, region in the target and configured to provide a signal indicative of a time of incidence thereon of at least one light pulse
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An apparatus (10), comprising: a laser light source (12) configured to transmit at least one beam of light pulses (L) towards a target, projecting at least one corresponding beam spot (P) thereon, and an array of sensors (16) with a plurality of sensors (16ij) distributed according to a grid (G), a sensor (16ij) in the array of sensors (16) configured to sense a light pulse incident thereon in response to reflection of at least one light pulse (P) of the beam of light pulses (L) from a field of view, FOV, region (T) in the target, the sensor (16) of the array of sensors (16) further configured to provide a signal indicative of a time of incidence of at least one light pulse (R). A FOV region (T) of the array of sensors (16) is portioned into grid cells (gij) according to the grid (G). Each sensor (16i) in the array of sensors (16) is configured to sense at least one echo light pulse (R) reflected from a respective grid cell portion (gij) of the FOV region (T). The apparatus (10) comprises a beam steering arrangement (13, 14) configured to cyclically vary a direction of transmission of the beam of light pulses (L), projecting at least one light pulse (P) per grid cell (gij) in the portioned FOV region (T) of the array of sensors (16).