Piezoelectric Micromirror Scanning for Rapid Abnormality Detection
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Solution Overview
Problem
Existing methods for detecting abnormal operations in micromirror devices, such as those used in LiDAR and HUD, are unable to do so at high speed due to the need to acquire and evaluate waveforms over one swing period, limiting their effectiveness in identifying dangerous conditions like continuous laser emission at a fixed point.
Innovation Solution
An optical scanning device with a micromirror device that swings around two orthogonal axes, utilizing piezoelectric actuators and sensors to detect fluctuations in output signals within a time interval shorter than 10% of the swing period, allowing for rapid abnormality detection through a comparator-based system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If waveform acquisition and evaluation over one swing period is performed to detect mirror amplitude, then measurement precision is improved, but detection speed deteriorates
Solution Approach 1:
The patent extracts only the essential feature needed for abnormality detection - the maximum value of the output signal during the swing period - rather than analyzing the entire waveform. This extraction approach maintains measurement precision for detecting amplitude abnormalities while enabling much faster detection compared to full waveform analysis.
Solution Approach 2:
Instead of performing complete waveform acquisition and evaluation over the entire swing period, the patent uses a simplified approach that monitors only the maximum signal value. This partial action approach provides sufficient information for abnormality detection while dramatically reducing the processing time and computational load.
2Device complexity
If current monitoring of driving piezoelectric portion is performed to detect short circuit, then detection simplicity is improved, but detection capability deteriorates
Solution Approach 1:
The patent makes the output signal monitoring serve multiple detection purposes simultaneously. By analyzing the maximum value and temporal fluctuations of the output signal from the piezoelectric element, the system can detect various types of abnormalities including but not limited to short circuits, enabling comprehensive monitoring without additional sensors.
Solution Approach 2:
The patent implements feedback monitoring by continuously comparing the output signal characteristics against expected ranges. The system uses the maximum value and fluctuation analysis to provide real-time feedback on mirror operation status, enabling reliable detection of multiple abnormal conditions while maintaining relatively simple implementation.
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
Enables rapid detection of abnormal mirror operations, preventing dangerous continuous laser emission by identifying deviations in output signals within a fraction of the swing period, thereby enhancing user safety.
Implementation Method 1
a piezoelectric element that generates and outputs an electromotive force by the swinging of the mirror
Data Source
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AI summary
Provided are an optical scanning device and an abnormality detection method with which an abnormal operation of a mirror can be detected at high speed during the operation. An optical scanning device of the present disclosure includes: a micromirror device including a mirror that has a reflecting surface for reflecting light and is swingable around at least one axis, an actuator that allows the mirror to swing, and a piezoelectric element that generates and outputs electromotive force by the swinging of the mirror; a control device configured to control an operation of the actuator; and an abnormality detection device configured to detect an abnormal operation of the mirror based on a temporal fluctuation amount in an output signal from the piezoelectric element.