Scanner Laser Optics for Fast One-Dimensional LIDAR Scanning
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Solution Overview
Problem
Existing laser scanning projectors face challenges in maintaining the laser beam within an exit aperture during scanning and achieving a fast enough scanning rate for efficient two-dimensional raster scanning, particularly in distance determination applications.
Innovation Solution
An optical module that combines multiple laser sources to generate a combined laser beam with low divergence along the axis of movement and high divergence perpendicular to it, using a series of lenses and a MEMS mirror to create a one-dimensional scan pattern for three-dimensional mapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two-dimensional raster scanning is used, then complete scene mapping is achieved, but scanning rate becomes too slow for efficient distance determination
Solution Approach 1:
The patent extracts the scanning function to only one dimension (horizontal scanning) while relying on the inherent vertical divergence of the laser beam to cover the vertical field of view. This removes the need for vertical scanning mechanisms, dramatically increasing scanning rate while still achieving complete scene mapping through the beam's natural spread.
Solution Approach 2:
The patent transitions from two-dimensional scanning to one-dimensional scanning by utilizing the vertical divergence of the laser beam as a natural coverage mechanism. The beam's divergence in the vertical dimension replaces the need for active vertical scanning, effectively using physical beam properties to achieve dimensional coverage without mechanical complexity.
2Area of stationary object
If laser beam is scanned across wide field of view, then complete scene coverage is achieved, but beam may exit aperture and impinge on housing
Solution Approach 1:
The patent applies different divergence characteristics to different axes of the laser beam. The beam is engineered to have controlled divergence in the horizontal direction (along the scan axis) while maintaining tighter confinement in the vertical direction. This local differentiation of beam properties allows wide horizontal coverage while preventing vertical escape that would cause housing impingement.
Solution Approach 2:
The patent exploits the anisotropic divergence behavior of the laser beam, where divergence differs between horizontal and vertical dimensions. By aligning the primary scan direction with the axis of greater acceptable divergence, the system achieves wide field coverage in the scanning dimension while the perpendicular dimension naturally confines the beam within the aperture boundaries.
3Stability of the object's composition
If multiple laser sources are combined, then beam uniformity is improved, but optical complexity increases
Solution Approach 1:
The patent combines multiple laser sources into a single integrated optical module with unified beam delivery. The multiple lasers are optically coupled and scanned together as a single beam package, achieving uniform illumination and consistent beam properties while maintaining a compact, integrated structure rather than separate scanning systems for each laser.
Solution Approach 2:
The optical module is designed to perform multiple functions: combining multiple laser sources, collimating the combined beam, controlling divergence characteristics, and enabling one-dimensional scanning. This multi-functional integration achieves beam uniformity without proportionally increasing complexity, as a single optical train handles all these tasks simultaneously.
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 solution achieves a uniform, efficient laser beam that maintains beam uniformity and efficiency, allowing for compact design and effective three-dimensional mapping without impinging on the housing, with over 90% efficiency and constant irradiation pattern across varying temperatures and wavelengths.
Implementation Method 1
The optical module includes one or more laser sources and one or more microelectromechanical system (MEMS) mirrors that scan the laser beam produced by the one or more laser sources
Implementation Method 2
one or more microelectromechanical system (MEMS) mirrors that scan the laser beam produced by the one or more laser sources across the projection surface
Implementation Method 3
Optical elements may be employed along the path of the laser beam between the one or more laser sources and the one or more MEMS mirrors so as to focus or collimate the laser beam in desired ways
Data Source
AI summary
Disclosed herein is an efficient optical scanning system takes the output of a multi-laser bar emitter with high divergence and delivers a combined beam of long vertical stripes of optical power that have a nearly top hat distribution along a vertical scanning axis and a narrow width along a horizontal scanning axis. This line footprint of the combined beam is scanned by a mirror onto a scene for use as ranging light in a distance measurement system.