Solid-State Lidar Spot Pattern Projector
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Solution Overview
Problem
Existing LIDAR systems face challenges in achieving compactness, reliability, and cost-effectiveness due to high power requirements and mechanical scanning elements, while solid-state systems with discrete spot patterns suffer from non-uniformity and speckle noise, affecting accuracy and precision.
Innovation Solution
A projector system comprising a laser array, mixing chamber, and reshaping optical system that mixes and refocuses diverging laser beams to form a uniform discrete spot pattern, reducing coherence and speckle noise, and utilizing VCSEL chips in a tile configuration to enhance robustness and production efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high power lasers are used to achieve sufficient illumination intensity, then the illumination intensity is improved, but the device complexity and cost increase significantly
Solution Approach 1:
The patent combines multiple low-power VCSEL laser beams into a single unified illumination pattern by merging their light paths through a common lens system. This allows the system to achieve high illumination intensity through aggregated optical power rather than requiring a single high-power laser, thereby reducing overall system complexity while maintaining the required illumination intensity for accurate distance measurement.
2Measurement precision
If mechanical scanning systems are used to achieve discrete spot pattern illumination, then the measurement precision is improved, but the device complexity and reliability worsen
Solution Approach 1:
The patent replaces mechanical scanning systems with a solid-state optical solution using an array of VCSEL lasers. Instead of mechanically rotating or moving components to create discrete spot patterns, the system uses a fixed array of laser diodes that directly emit light in specific directions, achieving the same discrete illumination pattern through optical means rather than mechanical motion, thereby improving reliability and reducing complexity.
3Device complexity
If individual laser light sources are used to form discrete spots, then the device complexity is reduced, but the manufacturing precision worsens due to variations in individual source properties
Solution Approach 1:
The patent addresses variations in individual laser source properties by changing the optical parameters of the system through careful lens design and positioning. By adjusting the focal lengths and arrangements of the lenses, the system compensates for differences in wavelength, beam divergence, and intensity among individual VCSEL sources, transforming the raw output into a uniform spot pattern that maintains high manufacturing precision despite variations in the individual laser components.
4Use of energy by moving object
If VCSEL chips are used to reduce power requirements, then the use of energy is improved, but the manufacturing precision worsens due to variations in chip properties
Solution Approach 1:
The patent compensates for variations in VCSEL chip properties (wavelength, beam divergence, intensity) by changing the optical system parameters, specifically the lens characteristics and their arrangements. The lens system is designed to transform the variable output of individual VCSEL chips into a standardized, uniform spot pattern, allowing the system to achieve both low energy consumption and high manufacturing precision by optimizing the optical transformation rather than requiring perfectly uniform chips.
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 improves the accuracy and precision of LIDAR systems by producing a uniform spot pattern with reduced speckle noise, enabling reliable and cost-effective operation suitable for automotive applications.
Implementation Method 1
a mixing chamber configured for allowing the first laser beams to diverge until, for each first laser beam, at least a portion of light rays of the first laser beam is overlapping with light rays of adjacent first laser beams
Implementation Method 2
a reshaping optical system configured for receiving the overlapping light rays of the first laser beams exiting the mixing chamber, refocussing the overlapping light rays, and generating a plurality of discrete second laser beams
Implementation Method 3
a projector lens system configured for receiving the second laser beams and projecting the second laser beams towards the scene, wherein the projected second laser beams are forming the discrete spot pattern
Data Source
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AI summary
The present disclosure relates to a projector for a solid-state LIDAR system for determining distances to a scene. The projector is configured for illuminating the scene with a discrete spot pattern. The projector comprises a laser array having a plurality of discrete solid-state laser light sources for simultaneously emitting a first laser beam, a mixing chamber configured for receiving and allowing propagation of each of the first laser beams until at least a portion of light rays of each first laser beam is overlapping with at least a portion of light rays of adjacent first laser beams, a reshaping optical system configured for receiving the overlapping light rays of the first laser beams and for generating a plurality of second laser beams such that each second laser beam comprises light rays originating from multiple first laser beams, and a projector lens system for projecting the discrete spot pattern formed by the second laser beams towards the scene. The disclosure is also related to a solid-state LIDAR system comprising such a projector and a light receiving device for detecting reflected laser light.