LiDAR Deflector Stray Light Feedback for Distance Accuracy
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Solution Overview
Problem
Existing LiDAR systems face challenges in accurately measuring object distance due to variations in machining accuracy and environmental changes affecting the deflection angle and resonance frequency of the driving mirror, leading to inaccuracies in distance measurement.
Innovation Solution
An optical apparatus that includes a deflector, a light guide, and an optical member with a reflective area to generate stray light, allowing the controller to estimate and correct the optical inclined angle and resonance frequency of the driving mirror, ensuring accurate object positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a driving mirror is used to deflect light flux, then the optical apparatus can scan objects and measure distances, but variations in machining accuracy cause individual differences in deflection angle and resonance frequency, leading to measurement inaccuracies
Solution Approach 1:
The patent introduces a feedback mechanism where the controller detects the actual resonance frequency and deflection angle of the driving mirror through stray light analysis, then adjusts control parameters to compensate for deviations from design values. This closed-loop feedback system eliminates measurement inaccuracies caused by machining variations and environmental changes.
Solution Approach 2:
The system dynamically changes control parameters (voltage, frequency) based on detected actual performance of the driving mirror. By adjusting these parameters in real-time according to the mirror's actual resonance frequency and deflection characteristics, the system maintains accurate distance measurement despite individual differences in mirror manufacturing.
2Adaptability or versatility
If the deflection angle and resonance frequency change due to environmental changes, then the optical apparatus can adapt to different conditions, but accurate distance measurement becomes difficult when these parameters deviate from design values
Solution Approach 1:
The controller continuously monitors the driving mirror's actual performance under varying environmental conditions by analyzing stray light characteristics. This real-time feedback enables the system to detect and compensate for parameter drifts caused by temperature and atmospheric pressure changes, maintaining measurement accuracy across different environments.
Solution Approach 2:
The system performs preliminary detection of the driving mirror's resonance frequency and deflection angle using stray light before actual distance measurement begins. This preliminary characterization allows the controller to pre-adjust control parameters to match the current environmental conditions, ensuring accurate measurements from the start.
3Measurement precision
If additional mechanisms are added to correct for driving mirror variations, then measurement accuracy can be maintained, but device complexity and cost increase
Solution Approach 1:
The optical apparatus uses its own stray light (which would otherwise be wasted) to automatically characterize and correct for driving mirror variations. This self-service mechanism eliminates the need for external calibration devices or additional sensors, maintaining high measurement accuracy without increasing device complexity.
Solution Approach 2:
The patent converts the harmful effect of stray light (which causes measurement errors) into a beneficial resource for characterizing the driving mirror's actual performance. By detecting and utilizing this previously harmful stray light, the system achieves automatic calibration and compensation without adding any extra components.
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 enables accurate and stable measurement of object position by detecting and correcting the optical inclined angle and resonance frequency, even under environmental changes, without the need for additional mechanisms, thus simplifying and reducing costs.
Implementation Method 1
an optical member having a reflective area that makes first light which is part of the illumination light from the deflector incident on the deflector by reflection
Data Source
AI summary
An optical apparatus includes a deflector configured to deflect illumination light from a light source to scan an object, and configured to deflect reflected light from the object, a light guide configured to guide the illumination light form the light source to the deflector, and configured to guide the reflected light from the deflector to a light receiving element, an optical member having a reflective area that makes first light which is part of the illumination light from the deflector incident on the deflector by reflection, and a controller configured to obtain information regarding the deflector on the basis of information of the first light from the reflective area. In a cross-section including the optical path from the reflective area to the light guide, a width of the reflective area is smaller than a width of the illumination light on the reflective area.