3D Lidar Sensor Using Single Emitter and Mechanical Scanning
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Solution Overview
Problem
Mechanical-motion lidar sensors with multiple discrete lasers are costly and do not achieve optimal resolution, especially when the mounting platform is static, as they require scanning in planes defined by individual collimated lasers, which is not effective for applications like road or traffic monitoring.
Innovation Solution
A time-of-flight lidar sensor apparatus using a single emitter, such as a single laser or integrated multi-laser chip, coupled with optical phased arrays or diffractive/holographic optical elements, that images an elongated radiation pattern or sweeps a beam for one-dimensional sensing, combined with mechanical motion to cover the remaining dimensions, with a static external body and spinning internal components for three-dimensional sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple discrete individually packaged lasers are used, then the field of view coverage is improved, but the cost increases and resolution does not achieve optimal levels
Solution Approach 1:
The patent combines multiple laser functions into a single laser source by using optical scanning mechanisms (rotating mirrors or polygons) to direct the single laser beam across multiple angular positions, effectively replacing multiple discrete lasers with one consolidated emitter that achieves the same field of view coverage
Solution Approach 2:
The patent introduces dynamic scanning elements (rotating mirrors or polygons) that move the single laser beam through different angular positions over time, allowing the static single emitter to cover the same spatial area that would otherwise require multiple fixed emitters
2Area of stationary object
If multiple discrete individually packaged lasers are used, then the field of view coverage is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple laser emitters and their associated optical paths into a single laser source with a dynamic scanning system, reducing the number of discrete components, packaging requirements, and alignment complexities associated with multiple independent laser modules
Solution Approach 2:
The single laser source with scanning capability serves multiple functions that would otherwise require separate dedicated lasers, acting as a universal emitter that can be directed to any required angular position within the field of view
3Stability of the object's composition
If scanning is performed in planes defined by individual collimated lasers, then the mounting platform can be static, but the resolution does not achieve acceptable levels
Solution Approach 1:
The patent transitions from planar scanning within fixed laser beams to angular scanning in the elevation dimension using a rotating mirror or polygon, creating a three-dimensional scanning pattern that achieves acceptable resolution while maintaining static platform stability
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 provides cost-effective and high-resolution three-dimensional mapping and object detection without the need for multiple lasers, maintaining effectiveness even when the mounting platform is static, improving resolution and reducing costs.
Implementation Method 1
a single laser coupled to an optical phased array (OPA) that either images a radiation pattern whose envelope is elongated to provide one-dimensional sensing, or sweeps a beam in one dimension to provide one-dimensional sensing
Implementation Method 2
a single laser coupled to a diffractive optical element (DOE) ..., with either optical element imaging a radiation pattern whose envelope is elongated to provide one-dimensional sensing
Implementation Method 3
a single laser coupled to a diffractive optical element (DOE) or a holographic optical element (HOE), with either optical element imaging a radiation pattern whose envelope is elongated to provide one-dimensional sensing
Implementation Method 4
a mechanical motion (e.g., spinning or mirror/prism/lens/DOE/HOE/grating scanning) is used to cover the two dimensions not covered by the emitter, resulting in three-dimensional sensing
Implementation Method 5
measuring the time it takes photons to travel to said target or landscape and return after reflection to a receiver in the lidar module
Data Source
AI summary
An apparatus and method are used for three-dimensional sensing with a time-of-flight lidar sensor having a single emitter sensing in one dimension, at least one photodetector, and a mechanical means of scanning in two dimensions said emitter and at least one photodetector. The external case of the lidar is preferably static, and only internal components involve mechanical motion. In a preferred embodiment of said lidar when operated in the infrared, said external static case has a window that is visually opaque and essentially transparent to infrared radiation.