Optical Deflection Apparatus Actuator Abnormality Detection
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Solution Overview
Problem
Existing optical deflection apparatuses for laser beams lack effective mechanisms to detect and correct abnormalities in piezoelectric drive circuits, leading to potential failures and continuous irradiation of specific spots during scanning, especially in harsh environments like vehicles.
Innovation Solution
An optical deflection apparatus with a mirror unit, actuators, a drive controller, and an abnormality detector that detects issues in the actuators and adjusts the mirror unit's position using forced piezoelectric drive circuits to prevent laser beam deviation from a prescribed range, ensuring continuous scanning and preventing spot irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If piezoelectric drive circuits are used to control the mirror unit, then the optical scanning function is achieved, but abnormalities in the piezoelectric drive circuits may occur leading to laser beam deviation and continuous irradiation of specific spots
Solution Approach 1:
The patent introduces an abnormality detection mechanism that continuously monitors the piezoelectric drive circuits and provides feedback to the control unit. When an abnormality is detected, the control unit adjusts the drive signals to compensate for the deviation, thereby maintaining reliable optical scanning while preventing harmful laser beam deviation and continuous spot irradiation.
2Area of stationary object
If the mirror unit is controlled to scan the laser beam, then the scanning coverage is improved, but the system becomes more complex requiring multiple actuators and control mechanisms
Solution Approach 1:
The patent employs a multi-functional control unit that manages multiple actuators (first and second actuators) with unified control logic. The control unit can detect abnormalities in any actuator and compensate using the other actuator, providing universal coverage capability while simplifying the overall control architecture despite the presence of multiple components.
3Reliability
If abnormality detection and correction mechanisms are added, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The control unit performs self-diagnosis and self-correction by detecting abnormalities in the piezoelectric drive circuits and automatically adjusting the drive signals without external intervention. The system uses its own resources (the control unit and remaining healthy actuators) to compensate for failures, thereby improving reliability while minimizing the increase in device complexity.
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 effectively detects and corrects abnormalities in the piezoelectric drive circuits, preventing laser beam deviation and continuous irradiation of specific spots, enhancing the reliability and efficiency of optical scanning systems, particularly in challenging environments.
Implementation Method 1
A piezoelectric circuit including a piezoelectric element is mounted on the surface of each beam. Due to the extension and contraction of the piezoelectric element, the beams elastically deform to rotate the mirror unit around the main-scanning oscillation axis
Implementation Method 2
An elastic member is provided for each base. When a voltage is applied to the elastic member, the base elastically deforms, and the mirror unit oscillates around a sub-scanning axis
Implementation Method 3
The sub-scanning oscillation unit is supported by a supporting unit through an arm so as to be rotatable in the sub-scanning direction, and the mirror unit is supported by the sub-scanning oscillation unit through a plurality of beams in a main-scanning oscillation axis so as to be rotatable around the main-scanning oscillation axis
Data Source
AI summary
An optical deflection apparatus, an image projector, an optical writing unit, and an object recognition device. The optical deflection apparatus includes a mirror unit having a reflection plane, a plurality of actuators to move the mirror unit around a prescribed axis, a drive controller to control operation of the plurality of actuators, and an abnormality detector to detect an abnormality in at least one of the plurality of actuators. When the abnormality detector detects an abnormality in at least one of the plurality of actuators, the drive controller controls another one of the plurality of actuators to deflect a light flux incident on the mirror unit. The image projector includes the optical deflection apparatus, and a light source unit to emit a laser beam. The optical deflection apparatus projects an image formed by optically scanning the laser beam emitted from the light source unit.