Lidar Sensor Micro-Optical Beam Expansion
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Solution Overview
Problem
Conventional lidar sensors face limitations in range and sensitivity due to small beam diameters, leading to high absorption and scattering losses under adverse conditions, and are restricted by eye safety requirements, resulting in limited sampling frequencies and beam angles.
Innovation Solution
The use of micro-optical elements to widen the light beam, combined with a light-concentrating element, creates a larger scanning beam diameter while maintaining a smaller deflection mirror, allowing for high sampling frequencies and wide beam angles while ensuring eye safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the beam diameter is increased to reduce scattering losses and improve eye safety, then a larger deflection mirror is required, but this increases the moment of inertia and reduces sampling frequency
Solution Approach 1:
The patent divides the beam widening function into two separate stages: first, micro-optical elements create multiple divergent beams from the incident light; second, a light-concentrating element collects these divergent beams and transforms them into a parallel scanning beam with large diameter. This segmentation allows the deflection mirror to remain small while achieving the beam diameter needed for reduced scattering and improved eye safety.
Solution Approach 2:
The array of micro-optical elements acts as an intermediary between the small deflected beam and the large scanning beam. Each micro-optical element transforms the incident beam into a divergent beam, and the light-concentrating element then transforms these divergent beams into the final parallel scanning beam. This intermediary approach enables beam diameter increase without requiring a large deflection mirror.
2Object-affected harmful factors
If a macro scanning device is used to widen the beam for eye safety and reduced scattering, then the deflection mirror dimensions increase, but this limits the beam angle and frame rate
Solution Approach 1:
The patent segments the beam transformation process into two distinct functions: beam divergence creation by micro-optical elements and beam parallelization by the light-concentrating element. This allows the system to achieve large beam diameter for eye safety and reduced scattering while maintaining a small deflection mirror that can scan through large angular ranges at high frame rates.
Solution Approach 2:
The patent transforms the problem from a single-dimensional beam widening approach to a two-dimensional process: first diverging the beam in one dimension through micro-optical elements, then parallelizing it in another dimension through the light-concentrating element. This dimensional transformation enables large beam angles without requiring a large deflection mirror.
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 configuration enhances the lidar sensor's sensitivity and range by reducing scattering losses and maintaining eye safety, enabling high frame rates and large beam angles without the need for large, heavy deflection mirrors.
Implementation Method 1
an array of micro-optical elements, each one of which, in response to being impinged upon by this light beam, is widened into a divergent beam
Implementation Method 2
a light-concentrating element is configured at a distance from the array of micro-optical elements. It transforms the divergent beam into a beam which forms the scanning beam and whose beam diameter is larger than that of the deflected beam
Implementation Method 3
a movable deflection mirror for producing a scanning beam that sweeps across a monitored space by deflecting a light beam emitted by the light source
Data Source
AI summary
A lidar sensor, especially for motor vehicles, having a light source, a movable deflection mirror for producing a scanning beam that sweeps across a monitored space by deflecting a light beam emitted by the light source, and having an optical receiver for detecting light reflected by an object hit by the scanning beam in the monitored space. The light source and the deflection mirror are adapted for using the deflected light beam to scan an array of micro-optical elements, each of which, in response to being impinged upon by this light beam, widens it into a divergent beam; and, configured at a distance from the array of micro-optical elements, is a light-concentrating element that transforms the divergent beam into a beam which forms the scanning beam and whose beam diameter is larger than that of the deflected beam.